Rethinking ICT4D Impact Assessments: reflections from the Siyakhula Living Lab in South Africa
- Mthoko, Hafeni, Khene, Caroline
- Authors: Mthoko, Hafeni , Khene, Caroline
- Date: 2019
- Language: English
- Type: text , conference paper
- Identifier: http://hdl.handle.net/10962/105286 , vital:32495 , https://doi.org/10.1007/978-3-030-11235-6_4
- Description: The approach to outcome and impact assessments of ICTD has often relied solely on identifying project effects in relation to project baseline data; however, such an approach limits the potential learning that could be occurring throughout a project’s lifecycle. Impact assessments should be conducted in a comprehensive manner, taking into account the evaluation data that has been captured from the initiation of the project through to its implementation, and beyond. This study sought to reflect on the implementation of an impact assessment framework that is based on a comprehensive approach to evaluation. The framework was implemented in the Siyakhula Living Lab to assess for its outcomes and impacts on the community. A pragmatic approach was applied through a reflective process, to assess the utility of the framework within this context. Semi-structured interviews with project stakeholders were conducted to further gain insight into the comprehensive approach to conducting impact assessments. It was found that a comprehensive approach to assessing impacts provided a meaningful way to understand the effects of the ICTD initiative, and provided an overview of project areas that required improvement. However, it was found that the proposed assessment framework required a customisation component in order to modify it to better suit the project context. The way in which future impact assessments are conducted can draw on the lessons gained from following a more comprehensive approach to evaluation, and thus improve learning over time.
- Full Text: false
- Date Issued: 2019
- Authors: Mthoko, Hafeni , Khene, Caroline
- Date: 2019
- Language: English
- Type: text , conference paper
- Identifier: http://hdl.handle.net/10962/105286 , vital:32495 , https://doi.org/10.1007/978-3-030-11235-6_4
- Description: The approach to outcome and impact assessments of ICTD has often relied solely on identifying project effects in relation to project baseline data; however, such an approach limits the potential learning that could be occurring throughout a project’s lifecycle. Impact assessments should be conducted in a comprehensive manner, taking into account the evaluation data that has been captured from the initiation of the project through to its implementation, and beyond. This study sought to reflect on the implementation of an impact assessment framework that is based on a comprehensive approach to evaluation. The framework was implemented in the Siyakhula Living Lab to assess for its outcomes and impacts on the community. A pragmatic approach was applied through a reflective process, to assess the utility of the framework within this context. Semi-structured interviews with project stakeholders were conducted to further gain insight into the comprehensive approach to conducting impact assessments. It was found that a comprehensive approach to assessing impacts provided a meaningful way to understand the effects of the ICTD initiative, and provided an overview of project areas that required improvement. However, it was found that the proposed assessment framework required a customisation component in order to modify it to better suit the project context. The way in which future impact assessments are conducted can draw on the lessons gained from following a more comprehensive approach to evaluation, and thus improve learning over time.
- Full Text: false
- Date Issued: 2019
Retracted COVID-19 Papers and the level of 'citation pollution': a preliminary analysis and directions for future research
- Van der Walt, Wynand, Willems, Kris A, Friedrich, Wernher, Hatsu, Sylvester, Krauss, Kirstin
- Authors: Van der Walt, Wynand , Willems, Kris A , Friedrich, Wernher , Hatsu, Sylvester , Krauss, Kirstin
- Date: 2020
- Subjects: Retraction watch , Research -- Evaluation , Bibliographical citations -- Evaluation , Science publishing -- Corrupt practices , Scholarly publishing -- Corrupt practices , Learning and scholarship -- Corrupt practices , Medical publishing -- Corrupt practices , COVID-19 (Disease) -- Publishing
- Language: English
- Type: Article , text
- Identifier: http://hdl.handle.net/10962/167732 , vital:41508 , https://www.abd-bvd.be/nl/bladen-voor-documentatie/2020-3-4/
- Description: Retraction Watch maintains a "running list" of retracted papers on Covid-19 related research. By the end of September 2020, thirty-three retracted Covid-19 papers were listed. We analysed these retracted papers, focusing specifically on how they have been cited by review papers, and subsequently how they have penetrated and potentially distorted public discourse and legitimate research on Covid-19. The study demonstrates the need for more in-depth studies that focus on the phenomenon of citation pollution. We show that the "Covid-19 publication race", amplified by a pressure-to-publish research culture, distorted published science on Covid-19. We highlight the urgency to engage popular media and critical decision makers on how to distinguish between questionable and legitimate science. We also emphasise the importance of dealing with illegitimate research in a timely manner, both from a scholarly communications and research quality perspective. , Retraction Watch maintient une "liste courante" des articles rétractés sur les recherches liées au Covid-19. Fin septembre 2020, trente-trois articles rétractés sur le Covid-19 étaient répertoriés. Nous avons analysé ces articles rétractés, en nous concentrant spécifiquement sur la façon dont ils ont été cités par d'autres articles, et ensuite sur la façon dont ils ont pénétré et potentiellement faussé le discours public et la recherche légitime sur le Covid-19. L'étude démontre le besoin d'études plus approfondies qui se concentrent sur le phénomène de la pollution des citations. Nous montrons que la "course à la publication sur le Covid-19", amplifiée par une culture de la pression à la publication de la recherche, a déformé l'information scientifique publiée sur le Covid-19. Nous soulignons l'urgence d'engager les médias populaires et les décideurs critiques sur la manière de distinguer la science douteuse de la science légitime. Nous soulignons également l'importance de traiter rapidement les recherches illégitimes, tant du point de vue de la communication scientifique que de la qualité de la recherche. , Retraction Watch houdt een "lopende lijst" bij van ingetrokken papieren over Covid-19-gerelateerd onderzoek. Eind september 2020 waren drieëndertig ingetrokken Covid-19 papieren op de lijst geplaatst. We hebben deze ingetrokken papieren geanalyseerd, waarbij we ons specifiek hebben gericht op de manier waarop ze zijn geciteerd door review papers, en vervolgens op de manier waarop ze zijn doorgedrongen en mogelijk vervormd in het publieke discours en het legitieme onderzoek naar Covid-19. De studie toont aan dat er behoefte is aan meer diepgaande studies die zich richten op het fenomeen van de citatievervuiling. We tonen aan dat de "Covid-19-publicatierace", versterkt door een druk om te publiceren onderzoekscultuur, de gepubliceerde wetenschap over Covid-19 vertekend heeft. We benadrukken de urgentie om de populaire media en kritische besluitvormers te betrekken bij het maken van een onderscheid tussen twijfelachtige en legitieme wetenschap. We benadrukken ook het belang van het tijdig aanpakken van onrechtmatig onderzoek, zowel vanuit het oogpunt van wetenschappelijke communicatie als vanuit het oogpunt van de kwaliteit van het onderzoek.
- Full Text:
- Date Issued: 2020
- Authors: Van der Walt, Wynand , Willems, Kris A , Friedrich, Wernher , Hatsu, Sylvester , Krauss, Kirstin
- Date: 2020
- Subjects: Retraction watch , Research -- Evaluation , Bibliographical citations -- Evaluation , Science publishing -- Corrupt practices , Scholarly publishing -- Corrupt practices , Learning and scholarship -- Corrupt practices , Medical publishing -- Corrupt practices , COVID-19 (Disease) -- Publishing
- Language: English
- Type: Article , text
- Identifier: http://hdl.handle.net/10962/167732 , vital:41508 , https://www.abd-bvd.be/nl/bladen-voor-documentatie/2020-3-4/
- Description: Retraction Watch maintains a "running list" of retracted papers on Covid-19 related research. By the end of September 2020, thirty-three retracted Covid-19 papers were listed. We analysed these retracted papers, focusing specifically on how they have been cited by review papers, and subsequently how they have penetrated and potentially distorted public discourse and legitimate research on Covid-19. The study demonstrates the need for more in-depth studies that focus on the phenomenon of citation pollution. We show that the "Covid-19 publication race", amplified by a pressure-to-publish research culture, distorted published science on Covid-19. We highlight the urgency to engage popular media and critical decision makers on how to distinguish between questionable and legitimate science. We also emphasise the importance of dealing with illegitimate research in a timely manner, both from a scholarly communications and research quality perspective. , Retraction Watch maintient une "liste courante" des articles rétractés sur les recherches liées au Covid-19. Fin septembre 2020, trente-trois articles rétractés sur le Covid-19 étaient répertoriés. Nous avons analysé ces articles rétractés, en nous concentrant spécifiquement sur la façon dont ils ont été cités par d'autres articles, et ensuite sur la façon dont ils ont pénétré et potentiellement faussé le discours public et la recherche légitime sur le Covid-19. L'étude démontre le besoin d'études plus approfondies qui se concentrent sur le phénomène de la pollution des citations. Nous montrons que la "course à la publication sur le Covid-19", amplifiée par une culture de la pression à la publication de la recherche, a déformé l'information scientifique publiée sur le Covid-19. Nous soulignons l'urgence d'engager les médias populaires et les décideurs critiques sur la manière de distinguer la science douteuse de la science légitime. Nous soulignons également l'importance de traiter rapidement les recherches illégitimes, tant du point de vue de la communication scientifique que de la qualité de la recherche. , Retraction Watch houdt een "lopende lijst" bij van ingetrokken papieren over Covid-19-gerelateerd onderzoek. Eind september 2020 waren drieëndertig ingetrokken Covid-19 papieren op de lijst geplaatst. We hebben deze ingetrokken papieren geanalyseerd, waarbij we ons specifiek hebben gericht op de manier waarop ze zijn geciteerd door review papers, en vervolgens op de manier waarop ze zijn doorgedrongen en mogelijk vervormd in het publieke discours en het legitieme onderzoek naar Covid-19. De studie toont aan dat er behoefte is aan meer diepgaande studies die zich richten op het fenomeen van de citatievervuiling. We tonen aan dat de "Covid-19-publicatierace", versterkt door een druk om te publiceren onderzoekscultuur, de gepubliceerde wetenschap over Covid-19 vertekend heeft. We benadrukken de urgentie om de populaire media en kritische besluitvormers te betrekken bij het maken van een onderscheid tussen twijfelachtige en legitieme wetenschap. We benadrukken ook het belang van het tijdig aanpakken van onrechtmatig onderzoek, zowel vanuit het oogpunt van wetenschappelijke communicatie als vanuit het oogpunt van de kwaliteit van het onderzoek.
- Full Text:
- Date Issued: 2020
Rhodes University 1981 Graduation Ceremonies Address
- Authors: Henderson, Derek Scott
- Date: 1981
- Language: English
- Type: text
- Identifier: vital:7428 , http://hdl.handle.net/10962/d1018305
- Full Text:
- Date Issued: 1981
- Authors: Henderson, Derek Scott
- Date: 1981
- Language: English
- Type: text
- Identifier: vital:7428 , http://hdl.handle.net/10962/d1018305
- Full Text:
- Date Issued: 1981
Rhodes University 1986 Graduation Ceremonies Address
- Authors: Henderson, Derek Scott
- Date: 1986
- Language: English
- Type: text
- Identifier: vital:7517 , http://hdl.handle.net/10962/d1018394
- Full Text:
- Date Issued: 1986
- Authors: Henderson, Derek Scott
- Date: 1986
- Language: English
- Type: text
- Identifier: vital:7517 , http://hdl.handle.net/10962/d1018394
- Full Text:
- Date Issued: 1986
Rhodes University Graduation Ceremony 1956
- Authors: Rhodes University
- Date: 1956
- Language: English
- Type: text
- Identifier: vital:8090 , http://hdl.handle.net/10962/d1004400
- Description: Rhodes University Graduation Ceremony in the University Great Hall on Friday , 6th April, 1956 at 8 p.m. [and] Graduation Ceremony held in April 1956: University College of Fort Hare. Graduation Ceremony at Fort Hare on Friday, April 27th ,1956 at 10:00a.m.
- Full Text:
- Date Issued: 1956
- Authors: Rhodes University
- Date: 1956
- Language: English
- Type: text
- Identifier: vital:8090 , http://hdl.handle.net/10962/d1004400
- Description: Rhodes University Graduation Ceremony in the University Great Hall on Friday , 6th April, 1956 at 8 p.m. [and] Graduation Ceremony held in April 1956: University College of Fort Hare. Graduation Ceremony at Fort Hare on Friday, April 27th ,1956 at 10:00a.m.
- Full Text:
- Date Issued: 1956
Riding the waves: Journalism education in post-apartheid South Africa
- Garman, Anthea, van der Merwe, Mia
- Authors: Garman, Anthea , van der Merwe, Mia
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/158405 , vital:40181 , https://0-doi.org.wam.seals.ac.za/10.1177/1077695817720679
- Description: Since 1994, South African journalism education has undergone waves of introspection about curricula and methods of teaching as educators respond to the challenging realities of the post-apartheid environment. The most recent challenge to journalism educators is the student protests which started at the end of 2015, questioning the high costs of education and demanding “decolonization” of curricula. The traditional alignment with media companies has also been upended as the drastic contraction of newsrooms removes the promise of jobs upon graduation and the swiftly shifting digital terrain rearranges the financial basis of all journalism. These factors introduce a dynamism and uncertainty into South African journalism that educators are compelled to respond to with imagination and principle.
- Full Text:
- Date Issued: 2017
- Authors: Garman, Anthea , van der Merwe, Mia
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/158405 , vital:40181 , https://0-doi.org.wam.seals.ac.za/10.1177/1077695817720679
- Description: Since 1994, South African journalism education has undergone waves of introspection about curricula and methods of teaching as educators respond to the challenging realities of the post-apartheid environment. The most recent challenge to journalism educators is the student protests which started at the end of 2015, questioning the high costs of education and demanding “decolonization” of curricula. The traditional alignment with media companies has also been upended as the drastic contraction of newsrooms removes the promise of jobs upon graduation and the swiftly shifting digital terrain rearranges the financial basis of all journalism. These factors introduce a dynamism and uncertainty into South African journalism that educators are compelled to respond to with imagination and principle.
- Full Text:
- Date Issued: 2017
Scientific frontiers in the management of coral reefs
- Aswani, Shankar, Mumby, Peter J, Baker, Andrew, Christie, Patrick, McCook, Laurence J, Steneck, Robert S, Richmond, Robert H
- Authors: Aswani, Shankar , Mumby, Peter J , Baker, Andrew , Christie, Patrick , McCook, Laurence J , Steneck, Robert S , Richmond, Robert H
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70582 , vital:29677 , https://doi.org/10.3389/fmars.2015.00050
- Description: Coral reefs are subjected globally to a variety of natural and anthropogenic stressors that often act synergistically. Today, reversing ongoing and future coral reef degradation presents significant challenges and countering this negative trend will take considerable efforts and investments. Scientific knowledge can inform and guide the requisite decision-making process and offer practical solutions to the problem of protection as the effects of climate change exacerbate. However, implementation of solutions presently lags far behind the pace required to reverse global declines, and there is a need for an urgent and significant step-up in the extent and range of strategies being implemented. In this paper, we consider scientific frontiers in natural and social science research that can help build stronger support for reef management and improve the efficacy of interventions. We cover various areas including: (1) enhancing the case for reef conservation and management, (2) dealing with local stressors on reefs, (3) addressing global climate change impacts, (4) and reviewing various approaches to the governance of coral reefs. In sum, we consider scientific frontiers in natural and social science that will require further attention in coming years as managers work toward building stronger support for reef management and improve the efficacy of local interventions.
- Full Text:
- Date Issued: 2015
- Authors: Aswani, Shankar , Mumby, Peter J , Baker, Andrew , Christie, Patrick , McCook, Laurence J , Steneck, Robert S , Richmond, Robert H
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/70582 , vital:29677 , https://doi.org/10.3389/fmars.2015.00050
- Description: Coral reefs are subjected globally to a variety of natural and anthropogenic stressors that often act synergistically. Today, reversing ongoing and future coral reef degradation presents significant challenges and countering this negative trend will take considerable efforts and investments. Scientific knowledge can inform and guide the requisite decision-making process and offer practical solutions to the problem of protection as the effects of climate change exacerbate. However, implementation of solutions presently lags far behind the pace required to reverse global declines, and there is a need for an urgent and significant step-up in the extent and range of strategies being implemented. In this paper, we consider scientific frontiers in natural and social science research that can help build stronger support for reef management and improve the efficacy of interventions. We cover various areas including: (1) enhancing the case for reef conservation and management, (2) dealing with local stressors on reefs, (3) addressing global climate change impacts, (4) and reviewing various approaches to the governance of coral reefs. In sum, we consider scientific frontiers in natural and social science that will require further attention in coming years as managers work toward building stronger support for reef management and improve the efficacy of local interventions.
- Full Text:
- Date Issued: 2015
Simultaneous liposomal encapsulation of antibiotics and proteins: co-loading and characterization of rifampicin and Human Serum Albumin in soy-liposomes
- Bapolisi, Alain M, Nkanga, Christian I, Walker, Roderick B, Krause, Rui W M
- Authors: Bapolisi, Alain M , Nkanga, Christian I , Walker, Roderick B , Krause, Rui W M
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148617 , vital:38755 , https://doi.org/10.1016/j.jddst.2020.101751
- Description: The recurrent development of resistance to antimicrobial agents threatens the ability for successful treatment of infectious diseases. Hydrophobic antibiotics such as rifampicin (Rif) are particularly affected due to poor bioavailability. On the other hand, proteins play important roles in drug delivery and release. Further, the combination of antimicrobials with therapeutic proteins and their encapsulation in liposomes seems a promising approach for improvement of antimicrobial efficacy. This study aimed to encapsulate Rif simultaneously with a large protein, Human Serum Albumin (HSA) in liposomes made from an inexpensive crude soy lecithin (CSL).
- Full Text:
- Date Issued: 2020
- Authors: Bapolisi, Alain M , Nkanga, Christian I , Walker, Roderick B , Krause, Rui W M
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148617 , vital:38755 , https://doi.org/10.1016/j.jddst.2020.101751
- Description: The recurrent development of resistance to antimicrobial agents threatens the ability for successful treatment of infectious diseases. Hydrophobic antibiotics such as rifampicin (Rif) are particularly affected due to poor bioavailability. On the other hand, proteins play important roles in drug delivery and release. Further, the combination of antimicrobials with therapeutic proteins and their encapsulation in liposomes seems a promising approach for improvement of antimicrobial efficacy. This study aimed to encapsulate Rif simultaneously with a large protein, Human Serum Albumin (HSA) in liposomes made from an inexpensive crude soy lecithin (CSL).
- Full Text:
- Date Issued: 2020
Sociodemographic inequities associated with participation in leisure-time physical activity in sub-Saharan Africa: an individual participant data meta-analysis
- Longo-Mbenza, Benjamin, Barr, Anna Louise, Partap, Uttara, Young, Elizabeth H, Agoudavi, Kokou, Balde, Naby, Kagaruki, Gibson B, Mayige, Mary T, Mutungi, Gerald, Mwalim, Omar, Wesseh, Chea S, Bahendeka, Silver K, Guwatudde, David, Jørgensen, Jutta M Adelin, Bovet, Pascal, Motala, Ayesha A, Sandhu, Manjinder S
- Authors: Longo-Mbenza, Benjamin , Barr, Anna Louise , Partap, Uttara , Young, Elizabeth H , Agoudavi, Kokou , Balde, Naby , Kagaruki, Gibson B , Mayige, Mary T , Mutungi, Gerald , Mwalim, Omar , Wesseh, Chea S , Bahendeka, Silver K , Guwatudde, David , Jørgensen, Jutta M Adelin , Bovet, Pascal , Motala, Ayesha A , Sandhu, Manjinder S
- Date: 2020-06-15
- Subjects: Recreation. Use of leisure time , Occupational therapy , Health surveys
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/3378 , vital:43337 , https://doi.org/10.1186/s12889-020-08987-w
- Description: Leisure-time physical activity (LTPA) is an important contributor to total physical activity and the focus of many interventions promoting activity in high-income populations. Little is known about LTPA in subSaharan Africa (SSA), and with expected declines in physical activity due to rapid urbanisation and lifestyle changes we aimed to assess the sociodemographic differences in the prevalence of LTPA in the adult populations of this region to identify potential barriers for equitable participation. A two-step individual participant data meta-analysis was conducted using data collected in SSA through 10 population health surveys that included the Global Physical Activity Questionnaire. For each sociodemographic characteristic, the pooled adjusted prevalence and risk ratios (RRs) for participation in LTPA were calculated using the random effects method. Between-study heterogeneity was explored through meta-regression analyses and tests for interaction. Across the 10 populations (N = 26,022), 18.9% (95%CI: 14.3, 24.1; I2 = 99.0%) of adults (≥ 18 years) participated in LTPA. Men were more likely to participate in LTPA compared with women (RR for women: 0.43; 95%CI: 0.32, 0.60; P less than 0.001; I2 = 97.5%), while age was inversely associated with participation. Higher levels of education were associated with increased LTPA participation (RR: 1.30; 95%CI: 1.09, 1.55; P = 0.004; I2 = 98.1%), with those living in rural areas or self-employed less likely to participate in LTPA. These associations remained after adjusting for time spent physically active at work or through active travel. In these populations, participation in LTPA was low, and strongly associated with sex, age, education, self-employment and urban residence. Identifying the potential barriers that reduce participation in these groups is necessary to enable equitable access to the health and social benefits associated with LTPA.
- Full Text:
- Date Issued: 2020-06-15
- Authors: Longo-Mbenza, Benjamin , Barr, Anna Louise , Partap, Uttara , Young, Elizabeth H , Agoudavi, Kokou , Balde, Naby , Kagaruki, Gibson B , Mayige, Mary T , Mutungi, Gerald , Mwalim, Omar , Wesseh, Chea S , Bahendeka, Silver K , Guwatudde, David , Jørgensen, Jutta M Adelin , Bovet, Pascal , Motala, Ayesha A , Sandhu, Manjinder S
- Date: 2020-06-15
- Subjects: Recreation. Use of leisure time , Occupational therapy , Health surveys
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/3378 , vital:43337 , https://doi.org/10.1186/s12889-020-08987-w
- Description: Leisure-time physical activity (LTPA) is an important contributor to total physical activity and the focus of many interventions promoting activity in high-income populations. Little is known about LTPA in subSaharan Africa (SSA), and with expected declines in physical activity due to rapid urbanisation and lifestyle changes we aimed to assess the sociodemographic differences in the prevalence of LTPA in the adult populations of this region to identify potential barriers for equitable participation. A two-step individual participant data meta-analysis was conducted using data collected in SSA through 10 population health surveys that included the Global Physical Activity Questionnaire. For each sociodemographic characteristic, the pooled adjusted prevalence and risk ratios (RRs) for participation in LTPA were calculated using the random effects method. Between-study heterogeneity was explored through meta-regression analyses and tests for interaction. Across the 10 populations (N = 26,022), 18.9% (95%CI: 14.3, 24.1; I2 = 99.0%) of adults (≥ 18 years) participated in LTPA. Men were more likely to participate in LTPA compared with women (RR for women: 0.43; 95%CI: 0.32, 0.60; P less than 0.001; I2 = 97.5%), while age was inversely associated with participation. Higher levels of education were associated with increased LTPA participation (RR: 1.30; 95%CI: 1.09, 1.55; P = 0.004; I2 = 98.1%), with those living in rural areas or self-employed less likely to participate in LTPA. These associations remained after adjusting for time spent physically active at work or through active travel. In these populations, participation in LTPA was low, and strongly associated with sex, age, education, self-employment and urban residence. Identifying the potential barriers that reduce participation in these groups is necessary to enable equitable access to the health and social benefits associated with LTPA.
- Full Text:
- Date Issued: 2020-06-15
South African estuaries in the Anthropocene
- Authors: Perissinotto, Renzo
- Subjects: Estuaries -- South Africa , Geology, Stratigraphic -- Anthropocene , f-sa
- Language: English
- Type: text , Lectures
- Identifier: http://hdl.handle.net/10948/20977 , vital:29424
- Description: In the new geological epoch of total human dominance of the planet, already widely referred to as the “Anthropocene”, estuaries are among the most vulnerable ecosystems to the changes that man’s activities have imposed on the coastal zone. For the non-specialist, an estuary is a “semi-enclosed coastal body of water, which has a permanent or temporary connection with the open sea, and within which sea water is diluted with fresh water from land drainage”.
- Full Text:
- Authors: Perissinotto, Renzo
- Subjects: Estuaries -- South Africa , Geology, Stratigraphic -- Anthropocene , f-sa
- Language: English
- Type: text , Lectures
- Identifier: http://hdl.handle.net/10948/20977 , vital:29424
- Description: In the new geological epoch of total human dominance of the planet, already widely referred to as the “Anthropocene”, estuaries are among the most vulnerable ecosystems to the changes that man’s activities have imposed on the coastal zone. For the non-specialist, an estuary is a “semi-enclosed coastal body of water, which has a permanent or temporary connection with the open sea, and within which sea water is diluted with fresh water from land drainage”.
- Full Text:
Spatial description of hake-directed fishing activity off the west coast of South Africa
- Fairweather, T P, Booth, Anthony J, Sauer, Warwick H H, Leslie, R W
- Authors: Fairweather, T P , Booth, Anthony J , Sauer, Warwick H H , Leslie, R W
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/127031 , vital:35945 , https://doi.10.2989/18142320609504129
- Description: Historically, the two species of Cape hakes Merluccius capensis and M. paradoxus off South Africa were commercially exploited exclusively by demersal trawling. In 1994, hake-directed demersal longline was introduced on an experimental basis, and in 1998 was initiated as a commercial fishing sector. The effect of a combined fleet composed of both trawlers and longliners on the Cape hake resource is not fully understood. Analysis of fishing intensity and catch-rate data revealed that the highest catch rates were found around the 400m and 500m isobaths for the trawl and longline fisheries respectively. Catch rates from both fishing sectors were also noted to be higher over sediments with a sand component. Differences between areas of the highest fishing intensity and highest catch rates were noted. In addition to other factors, it is suggested that a ‘friction of distance’ effect applies — vessels will trade-off higher catch rates with the increased costs associated with fishing in deeper waters.
- Full Text:
- Date Issued: 2010
- Authors: Fairweather, T P , Booth, Anthony J , Sauer, Warwick H H , Leslie, R W
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/127031 , vital:35945 , https://doi.10.2989/18142320609504129
- Description: Historically, the two species of Cape hakes Merluccius capensis and M. paradoxus off South Africa were commercially exploited exclusively by demersal trawling. In 1994, hake-directed demersal longline was introduced on an experimental basis, and in 1998 was initiated as a commercial fishing sector. The effect of a combined fleet composed of both trawlers and longliners on the Cape hake resource is not fully understood. Analysis of fishing intensity and catch-rate data revealed that the highest catch rates were found around the 400m and 500m isobaths for the trawl and longline fisheries respectively. Catch rates from both fishing sectors were also noted to be higher over sediments with a sand component. Differences between areas of the highest fishing intensity and highest catch rates were noted. In addition to other factors, it is suggested that a ‘friction of distance’ effect applies — vessels will trade-off higher catch rates with the increased costs associated with fishing in deeper waters.
- Full Text:
- Date Issued: 2010
Spatial structure of recruitment in the mussel Perna perna at local scales: effects of adults, algae and recruit size
- Erlandsson, Johan, McQuaid, Christopher D
- Authors: Erlandsson, Johan , McQuaid, Christopher D
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6898 , http://hdl.handle.net/10962/d1011660
- Description: To test the assumption that there is no spatial structure in small-scale recruitment variability of rocky shore mussels, we examined spatial dependence in the distribution of density of recruits (late plantigrades: 0.5 to 3.5 mm; larger recruits: 3.5 to 10 mm) and adults of the brown mussel Perna perna within local scales (30 lags ranging between 0.35 and 10.5 m) in mid- and upper mussel beds. Spatial heterogeneity was estimated by analyzing scaling properties of semivariograms using a fractal approach. Relationships between density of mussel recruits and adults and biomass of the red alga Gelidium pristoides at the different scales were examined by cross-semivariograms. We found that the distribution of adults showed spatial dependence at all transects, often with higher spatial heterogeneity (higher fractal dimension, D) at smaller scales (1st scaling region). The distribution of larger recruits exhibited spatial dependence at all transects, revealing a spatial structure, which was related to that of adults. In contrast, the distribution of late plantigrades showed mainly spatial independence (random pattern; 1.97 < D ≤ 2). Densities of both size classes of recruits were positively related to those of adults at all transects and scales, but the relationship was stronger for larger recruits than late plantigrades, explaining why there was clearer spatial structure of larger recruits. The relationship with algae was mainly negative for larger recruits, while it tended to be positive at many scales for late plantigrades. Thus, both adult mussels and G. pristoides are suitable habitats for plantigrades, while mussels are the main habitat for larger recruits. This may mean that recruits on algae either die or migrate to mussel clumps at a certain size. This study highlights the importance of recruit size when analyzing recruitment patchiness of mussels, and has implications for sustainable management of P. perna.
- Full Text:
- Date Issued: 2004
- Authors: Erlandsson, Johan , McQuaid, Christopher D
- Date: 2004
- Language: English
- Type: Article
- Identifier: vital:6898 , http://hdl.handle.net/10962/d1011660
- Description: To test the assumption that there is no spatial structure in small-scale recruitment variability of rocky shore mussels, we examined spatial dependence in the distribution of density of recruits (late plantigrades: 0.5 to 3.5 mm; larger recruits: 3.5 to 10 mm) and adults of the brown mussel Perna perna within local scales (30 lags ranging between 0.35 and 10.5 m) in mid- and upper mussel beds. Spatial heterogeneity was estimated by analyzing scaling properties of semivariograms using a fractal approach. Relationships between density of mussel recruits and adults and biomass of the red alga Gelidium pristoides at the different scales were examined by cross-semivariograms. We found that the distribution of adults showed spatial dependence at all transects, often with higher spatial heterogeneity (higher fractal dimension, D) at smaller scales (1st scaling region). The distribution of larger recruits exhibited spatial dependence at all transects, revealing a spatial structure, which was related to that of adults. In contrast, the distribution of late plantigrades showed mainly spatial independence (random pattern; 1.97 < D ≤ 2). Densities of both size classes of recruits were positively related to those of adults at all transects and scales, but the relationship was stronger for larger recruits than late plantigrades, explaining why there was clearer spatial structure of larger recruits. The relationship with algae was mainly negative for larger recruits, while it tended to be positive at many scales for late plantigrades. Thus, both adult mussels and G. pristoides are suitable habitats for plantigrades, while mussels are the main habitat for larger recruits. This may mean that recruits on algae either die or migrate to mussel clumps at a certain size. This study highlights the importance of recruit size when analyzing recruitment patchiness of mussels, and has implications for sustainable management of P. perna.
- Full Text:
- Date Issued: 2004
Speaking to power through newspaper editorials in Zimbabwe:
- Nyaungwa, Mathew, Garman, Anthea
- Authors: Nyaungwa, Mathew , Garman, Anthea
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/158438 , vital:40186 , https://0-doi.org.wam.seals.ac.za/10.1386/jams.11.1.51_1
- Description: This article seeks to provide an insight into the complex role that editorials – a newspaper’s institutional voice – play in highly polarised political contexts. It focuses on how the editorials of two Zimbabwean daily newspapers – The Herald, a progovernment newspaper, and NewsDay, a perceived pro-opposition newspaper – spoke to those in power at a time of transition from a government of national unity to majoritarian rule in 2013. The study also sets out to understand how both the newspapers’ editorials over this time responded to a contested political domain. Qualitative content analysis, rhetorical analysis and in-depth interviews were used to consider the tactics employed in the editorials to question and challenge the decisions and behaviours of those in positions of authority. The research findings contradict the common view in Zimbabwe that the privately–owned media blindly support the opposition while the state-owned media do the same with ZANU-PF. The findings show that in the period in question both newspapers exploited the editorial as a space to urge politicians to think of the national common good.
- Full Text:
- Date Issued: 2019
- Authors: Nyaungwa, Mathew , Garman, Anthea
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/158438 , vital:40186 , https://0-doi.org.wam.seals.ac.za/10.1386/jams.11.1.51_1
- Description: This article seeks to provide an insight into the complex role that editorials – a newspaper’s institutional voice – play in highly polarised political contexts. It focuses on how the editorials of two Zimbabwean daily newspapers – The Herald, a progovernment newspaper, and NewsDay, a perceived pro-opposition newspaper – spoke to those in power at a time of transition from a government of national unity to majoritarian rule in 2013. The study also sets out to understand how both the newspapers’ editorials over this time responded to a contested political domain. Qualitative content analysis, rhetorical analysis and in-depth interviews were used to consider the tactics employed in the editorials to question and challenge the decisions and behaviours of those in positions of authority. The research findings contradict the common view in Zimbabwe that the privately–owned media blindly support the opposition while the state-owned media do the same with ZANU-PF. The findings show that in the period in question both newspapers exploited the editorial as a space to urge politicians to think of the national common good.
- Full Text:
- Date Issued: 2019
Spermiogenesis in three species of cicadas (Hemiptera: Cicadidae)
- Chawanji, A S, Hodgson, Alan N, Villet, Martin H, Sanborn, Allen F, Phillips, P K
- Authors: Chawanji, A S , Hodgson, Alan N , Villet, Martin H , Sanborn, Allen F , Phillips, P K
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6865 , http://hdl.handle.net/10962/d1011207
- Description: Spermiogenesis in three species of cicadas representing one cicadettine (Monomatapa matoposa Boulard) and two cicadines (Diceroprocta biconica [Walker] and Kongota punctigera [Walker]) was investigated by light and electron microscopy. Although spermiogenesis was occurring in the testis of adult males of all species, earlier spermiogenic stages were observed in D. biconica only. While spermiogenesis was similar to that described for other insects, some differences were noted. For example granular material did not assemble around the centriole to form a centriolar adjunct but did accumulate in the cytoplasm of early spermatids adjacent to a region of the nuclear membrane where nuclear pores were aggregated. In late spermatids this material accumulated anterior to the mitochondrial derivatives in a developing postero-lateral nuclear groove. While this material has been named the ‘centriolar adjunct’ by previous authors, its formation away from the centriole raises questions about its true identity. Second, during acrosome maturation an ante-acrosomal region of cytoplasm develops. Although present in later spermatids, this region is lost in spermatozoa. Interspecific variations in chromatin condensation patterns and the number of microtubule layers encircling the spermatid nucleus during spermiogenesis were noted.
- Full Text:
- Date Issued: 2007
- Authors: Chawanji, A S , Hodgson, Alan N , Villet, Martin H , Sanborn, Allen F , Phillips, P K
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6865 , http://hdl.handle.net/10962/d1011207
- Description: Spermiogenesis in three species of cicadas representing one cicadettine (Monomatapa matoposa Boulard) and two cicadines (Diceroprocta biconica [Walker] and Kongota punctigera [Walker]) was investigated by light and electron microscopy. Although spermiogenesis was occurring in the testis of adult males of all species, earlier spermiogenic stages were observed in D. biconica only. While spermiogenesis was similar to that described for other insects, some differences were noted. For example granular material did not assemble around the centriole to form a centriolar adjunct but did accumulate in the cytoplasm of early spermatids adjacent to a region of the nuclear membrane where nuclear pores were aggregated. In late spermatids this material accumulated anterior to the mitochondrial derivatives in a developing postero-lateral nuclear groove. While this material has been named the ‘centriolar adjunct’ by previous authors, its formation away from the centriole raises questions about its true identity. Second, during acrosome maturation an ante-acrosomal region of cytoplasm develops. Although present in later spermatids, this region is lost in spermatozoa. Interspecific variations in chromatin condensation patterns and the number of microtubule layers encircling the spermatid nucleus during spermiogenesis were noted.
- Full Text:
- Date Issued: 2007
Stigma syndemics & symbolic (isms) in the context of HIV: ways of knowing in health care
- Authors: Naidoo, Joanne Rachel
- Subjects: Stigma (Social psychology) , HIV-positive persons -- Care , f-sa
- Language: English
- Type: text , Lectures
- Identifier: http://hdl.handle.net/10948/55010 , vital:48778
- Description: The negating effect of stigma on health outcomes has been widely established. Described as a hidden burden of disease, stigma significantly influences the inequities in health. The seminal work of Sociologist, Erving Goffman’s initially published in 1963 continue to underpin our current understanding of stigma as socially influenced through the symbolic interactions of everyday experiences that influences behaviour. Within the context of HIV, stigma remains a barrier in ending the epidemic and is associated with diminished health outcomes, health seeking patterns and poor quality of life. The significant advances in HIV treatment, has increased the life expectancy of people living with HIV, and has shifted the management of HIV as a manageable chronic illness. However the negative stigma outcomes experienced by people living with HIV remains. Moreover, the interactions of other syndemics (that is the co-existence of another disease/s, or social factors) further contributes to the stigma experienced by people living with HIV. This may refer to the co-existence of TB, depressive or other mental health disorder, younger woman, pregnancy, and occupations or work type industry, such as mini-bus taxi drivers, sex workers to name a few syndemics. Central to the health are the values and attributes of caring, towards the restorative process for sustained health and improved wellbeing. To enable care, there is a need for health care professionals to know how to care. Patterns of Knowing or Ways of Knowing developed by nurse theorist Barbra Carper (1975, 1978) and extended by Chinn and Kramer (2008) has become widely applied in nursing and health professions education and training. Ways of knowing acknowledges five inter related facets (empirical, ethical, personal, aesthetic and emancipatory) inherent in the provision of holistic care. The lecture will reflect on the syndemics associated with HIV related stigma, and the symbolic interactions with health care; in the provision of health care and in education and training of health care professionals. This will be framed against ways of knowing, how health care professionals know how to care, the inherent and learnt symbolic meanings in how care is provided, and its potential to demystify and eliminate the perpetuated HIV related stigma.
- Full Text:
- Authors: Naidoo, Joanne Rachel
- Subjects: Stigma (Social psychology) , HIV-positive persons -- Care , f-sa
- Language: English
- Type: text , Lectures
- Identifier: http://hdl.handle.net/10948/55010 , vital:48778
- Description: The negating effect of stigma on health outcomes has been widely established. Described as a hidden burden of disease, stigma significantly influences the inequities in health. The seminal work of Sociologist, Erving Goffman’s initially published in 1963 continue to underpin our current understanding of stigma as socially influenced through the symbolic interactions of everyday experiences that influences behaviour. Within the context of HIV, stigma remains a barrier in ending the epidemic and is associated with diminished health outcomes, health seeking patterns and poor quality of life. The significant advances in HIV treatment, has increased the life expectancy of people living with HIV, and has shifted the management of HIV as a manageable chronic illness. However the negative stigma outcomes experienced by people living with HIV remains. Moreover, the interactions of other syndemics (that is the co-existence of another disease/s, or social factors) further contributes to the stigma experienced by people living with HIV. This may refer to the co-existence of TB, depressive or other mental health disorder, younger woman, pregnancy, and occupations or work type industry, such as mini-bus taxi drivers, sex workers to name a few syndemics. Central to the health are the values and attributes of caring, towards the restorative process for sustained health and improved wellbeing. To enable care, there is a need for health care professionals to know how to care. Patterns of Knowing or Ways of Knowing developed by nurse theorist Barbra Carper (1975, 1978) and extended by Chinn and Kramer (2008) has become widely applied in nursing and health professions education and training. Ways of knowing acknowledges five inter related facets (empirical, ethical, personal, aesthetic and emancipatory) inherent in the provision of holistic care. The lecture will reflect on the syndemics associated with HIV related stigma, and the symbolic interactions with health care; in the provision of health care and in education and training of health care professionals. This will be framed against ways of knowing, how health care professionals know how to care, the inherent and learnt symbolic meanings in how care is provided, and its potential to demystify and eliminate the perpetuated HIV related stigma.
- Full Text:
Structure based docking and molecular dynamic studies of plasmodial cysteine proteases against a South African natural compound and its analogs:
- Musyoka, Thommas M, Kanzi, Aquillah M, Lobb, Kevin A, Tastan Bishop, Özlem
- Authors: Musyoka, Thommas M , Kanzi, Aquillah M , Lobb, Kevin A , Tastan Bishop, Özlem
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148027 , vital:38703 , DOI: 10.1038/srep23690
- Description: Identification of potential drug targets as well as development of novel antimalarial chemotherapies with unique mode of actions due to drug resistance by Plasmodium parasites are inevitable. Falcipains (falcipain-2 and falcipain-3) of Plasmodium falciparum, which catalyse the haemoglobin degradation process, are validated drug targets. Previous attempts to develop peptide based drugs against these enzymes have been futile due to the poor pharmacological profiles and susceptibility to degradation by host enzymes. This study aimed to identify potential non-peptide inhibitors against falcipains and their homologs from other Plasmodium species.
- Full Text:
- Date Issued: 2016
- Authors: Musyoka, Thommas M , Kanzi, Aquillah M , Lobb, Kevin A , Tastan Bishop, Özlem
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148027 , vital:38703 , DOI: 10.1038/srep23690
- Description: Identification of potential drug targets as well as development of novel antimalarial chemotherapies with unique mode of actions due to drug resistance by Plasmodium parasites are inevitable. Falcipains (falcipain-2 and falcipain-3) of Plasmodium falciparum, which catalyse the haemoglobin degradation process, are validated drug targets. Previous attempts to develop peptide based drugs against these enzymes have been futile due to the poor pharmacological profiles and susceptibility to degradation by host enzymes. This study aimed to identify potential non-peptide inhibitors against falcipains and their homologs from other Plasmodium species.
- Full Text:
- Date Issued: 2016
Studies in Carangid fishes No.6: key to the western Indian Ocean species of the Genus Carangoides Bleeker, 1851, with a description of Carangoides Nitidus Smith
- Authors: Smith, Margaret M
- Date: 1972
- Language: English
- Type: text , Article
- Identifier: vital:7124 , http://hdl.handle.net/10962/d1004450
- Description: From introduction: Fishes in the family Carangidae commonly known as Jacks or Kingfishes are generally characterised by a silvery ovate body with s mall insignificant cycloid scales,a lateral line with curved anterior portion and a posterior straight portion bearing scules, a moderate mouth usually with feeble teeth, no dorsal and anal finlets, and a deeply forked caudal with a slender peduncle. A horizontally forwardly directed spine from the dorsal pterygiophore visible in front of the dorsal fin in shrunken or dried specimens, and the first two anal spines separate from the third and the rest of the fin are more pronounced in juvenile specimens.
- Full Text:
- Date Issued: 1972
- Authors: Smith, Margaret M
- Date: 1972
- Language: English
- Type: text , Article
- Identifier: vital:7124 , http://hdl.handle.net/10962/d1004450
- Description: From introduction: Fishes in the family Carangidae commonly known as Jacks or Kingfishes are generally characterised by a silvery ovate body with s mall insignificant cycloid scales,a lateral line with curved anterior portion and a posterior straight portion bearing scules, a moderate mouth usually with feeble teeth, no dorsal and anal finlets, and a deeply forked caudal with a slender peduncle. A horizontally forwardly directed spine from the dorsal pterygiophore visible in front of the dorsal fin in shrunken or dried specimens, and the first two anal spines separate from the third and the rest of the fin are more pronounced in juvenile specimens.
- Full Text:
- Date Issued: 1972
Study of Star-Forming Regions in the Peculiar Galaxies NGC 660, NGC 1512, NGC 4395, and NGC 4618:
- Smirnova, K I, Wiebe, D S, Moiseev, A V, Jozsa, G I G
- Authors: Smirnova, K I , Wiebe, D S , Moiseev, A V , Jozsa, G I G
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/160456 , vital:40447 , https://0-doi.org.wam.seals.ac.za/10.1134/S199034132003013X
- Description: The star-forming regions (SFRs) in the peculiar galaxies NGC 660, NGC 1512, NGC 4395 and NGC 4618 are studied. The relationships between such characteristics of star forming regions as UV, near- and far-IR fluxes, as well as in the Hα and HI lines, surface brightness in these ranges, and the scatter of the radial velocities of ionized and neutral hydrogen are considered. It is shown that in all the galaxies considered, the IR fluxes from SFRs are less than in the “normal” galaxies, but for different reasons: in the galaxies with signs of recent interaction NGC 660 and NGC 1512, this is due to the low surface brightness of SFRs; in the lopsided galaxies NGC 4395 and NGC 4618, the low brightness of SFRs in the infrared range is due to their compact size. These differences indicate that the star formation process depends not only on the morphological type of a galaxy, but also on many other factors.
- Full Text:
- Date Issued: 2020
- Authors: Smirnova, K I , Wiebe, D S , Moiseev, A V , Jozsa, G I G
- Date: 2020
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/160456 , vital:40447 , https://0-doi.org.wam.seals.ac.za/10.1134/S199034132003013X
- Description: The star-forming regions (SFRs) in the peculiar galaxies NGC 660, NGC 1512, NGC 4395 and NGC 4618 are studied. The relationships between such characteristics of star forming regions as UV, near- and far-IR fluxes, as well as in the Hα and HI lines, surface brightness in these ranges, and the scatter of the radial velocities of ionized and neutral hydrogen are considered. It is shown that in all the galaxies considered, the IR fluxes from SFRs are less than in the “normal” galaxies, but for different reasons: in the galaxies with signs of recent interaction NGC 660 and NGC 1512, this is due to the low surface brightness of SFRs; in the lopsided galaxies NGC 4395 and NGC 4618, the low brightness of SFRs in the infrared range is due to their compact size. These differences indicate that the star formation process depends not only on the morphological type of a galaxy, but also on many other factors.
- Full Text:
- Date Issued: 2020
Submission to Press Freedom Commission (PFC) on Media Self-regulation, Co-regulation or Statutory regulation in South Africa:
- Wasserman, Herman, Steenveld, Lynette N, Strelitz, Larry N, Amner, Roderick J, Boshoff, Priscilla A, Mathurine, Jude, Garman, Anthea
- Authors: Wasserman, Herman , Steenveld, Lynette N , Strelitz, Larry N , Amner, Roderick J , Boshoff, Priscilla A , Mathurine, Jude , Garman, Anthea
- Date: 2012
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/143571 , vital:38263 , ISBN , https://www.ru.ac.za/media/rhodesuniversity/content/ruhome/documents/JMS Submission to Press Freedom Commission.pdf
- Description: Prof Duncan has outlined the relative merits and demerits of self-regulation, co-regulation and deregulation, with which we are in broad agreement. She has also ably dealt with the three functions of regulatory bodies, namely the setting of ground rules for the industry to ensure best practice; enforcement of these; and adjudication of claims and counter claims re journalistic practice (Duncan 2012, p17). Finally, she has also taken up the issue of the necessity of accepting Third Party Complaints as one of the fundamental mechanisms by which citizens can make complaints on the basis of principle, rather than being personally aggrieved. While we are in broad agreement with her on these issues, we would like to highlight some further points for consideration.
- Full Text:
- Date Issued: 2012
- Authors: Wasserman, Herman , Steenveld, Lynette N , Strelitz, Larry N , Amner, Roderick J , Boshoff, Priscilla A , Mathurine, Jude , Garman, Anthea
- Date: 2012
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/143571 , vital:38263 , ISBN , https://www.ru.ac.za/media/rhodesuniversity/content/ruhome/documents/JMS Submission to Press Freedom Commission.pdf
- Description: Prof Duncan has outlined the relative merits and demerits of self-regulation, co-regulation and deregulation, with which we are in broad agreement. She has also ably dealt with the three functions of regulatory bodies, namely the setting of ground rules for the industry to ensure best practice; enforcement of these; and adjudication of claims and counter claims re journalistic practice (Duncan 2012, p17). Finally, she has also taken up the issue of the necessity of accepting Third Party Complaints as one of the fundamental mechanisms by which citizens can make complaints on the basis of principle, rather than being personally aggrieved. While we are in broad agreement with her on these issues, we would like to highlight some further points for consideration.
- Full Text:
- Date Issued: 2012
Supply-side ecology of the brown mussel, Perna perna: an investigation of spatial and temporal variation in, and coupling between, gamete release and larval supply
- McQuaid, Christopher D, Lawrie, S M
- Authors: McQuaid, Christopher D , Lawrie, S M
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6954 , http://hdl.handle.net/10962/d1011987
- Description: Sampling of recruitment-associated variables of Perna perna was done approximately monthly for 14 months at intertidal locations 500 m apart, nested within sites 25 km apart. Paired with intertidal locations were nearshore locations, 600 m to sea. Sampling assessed spawning, densities of larvae in the water column and densities of late plantigrades and juveniles on the shore. Major events in each variable were synchronous over larger scales (10s of kilometres) while subsidiary events were synchronised at smaller scales, varying within sites (100s of metres) or even within locations (metres). This suggests that the processes driving major events operated over large scales while processes operating at much more local scales drove less intense, more localised events. A major spawning event occurred at all locations in May–June 1998. Weaker spawning events occurred at different times in different locations. Larvae were found on 80% of sampling occasions, densities peaking in January–March 1998 and 1999 at all locations. Plantigrades and juveniles showed less clear patterns, with considerable residual variation. There was no sign of strong coupling among variables with few significant direct or cross correlations. The major sources of variability shifted from time to space as one progressed from spawning, to plantigrade density to juvenile density. For spawning, time was the most important source (58%) of heterogeneity and space accounted for little (8%) of the total variance. For larvae and late plantigrades, time was still the most important source of variability (41% and 33%, respectively), but space was a much more substantial component. For juveniles, small-scale (residual) spatial variability dominated total variability (75%). This strongly suggests the importance of hydrography and its effects on variation in delivery of larvae to the intertidal from offshore. These findings also indicate greater spatial heterogeneity as recruits age, reflecting small-scale variations in larval delivery and the increasing importance of post-settlement mortality.
- Full Text:
- Date Issued: 2005
- Authors: McQuaid, Christopher D , Lawrie, S M
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6954 , http://hdl.handle.net/10962/d1011987
- Description: Sampling of recruitment-associated variables of Perna perna was done approximately monthly for 14 months at intertidal locations 500 m apart, nested within sites 25 km apart. Paired with intertidal locations were nearshore locations, 600 m to sea. Sampling assessed spawning, densities of larvae in the water column and densities of late plantigrades and juveniles on the shore. Major events in each variable were synchronous over larger scales (10s of kilometres) while subsidiary events were synchronised at smaller scales, varying within sites (100s of metres) or even within locations (metres). This suggests that the processes driving major events operated over large scales while processes operating at much more local scales drove less intense, more localised events. A major spawning event occurred at all locations in May–June 1998. Weaker spawning events occurred at different times in different locations. Larvae were found on 80% of sampling occasions, densities peaking in January–March 1998 and 1999 at all locations. Plantigrades and juveniles showed less clear patterns, with considerable residual variation. There was no sign of strong coupling among variables with few significant direct or cross correlations. The major sources of variability shifted from time to space as one progressed from spawning, to plantigrade density to juvenile density. For spawning, time was the most important source (58%) of heterogeneity and space accounted for little (8%) of the total variance. For larvae and late plantigrades, time was still the most important source of variability (41% and 33%, respectively), but space was a much more substantial component. For juveniles, small-scale (residual) spatial variability dominated total variability (75%). This strongly suggests the importance of hydrography and its effects on variation in delivery of larvae to the intertidal from offshore. These findings also indicate greater spatial heterogeneity as recruits age, reflecting small-scale variations in larval delivery and the increasing importance of post-settlement mortality.
- Full Text:
- Date Issued: 2005