1,720,972 research outputs found
Estimates of life-history and growth parameters of exploited fish species in lakes Edward and George: Implications on exploitation status, population dynamics, management, and conservation of native species
No full textAdequate knowledge is essential for responsible inland fisheries. However, many inland fisheries lack monitoring, and therefore, decision-making for fisheries management is not reliable. In this paper, we used data from surveys and literature to estimate the life-history and growth parameters of 16 exploited fish stocks in the Ugandan part of Lake Edward and Lake George (East Africa). The estimated parameters are pivotal indicators of fish stock status, particularly in data-poor fisheries. The estimated parameters included maximum length (Lmax) and mean length (Lmean) as indicators of size structure in experimental and commercial catches, coefficients of length-weight relationships, length at 50% maturity (Lm50), fecundity, von Bertalanffy parameters, total mortality (Z), and natural mortality (M). These parameters were estimated using empirical formulae, statistical methods, and analyses of length frequencies. Only two stocks of semutundu Bagrus docmak exhibited significant and increasing trends in Lmax (Lake Edward) and Lmean (Lake George). The estimates for the remaining parameters were consistent with those in FishBase and other literature resources, either for the same species or related species. This consistency indicates their reliability for application in decision-making and further assessments. Some parameters showed evidence of unsustainable fishing. For example, estimates of Lm50 for four of the assessed stocks belonging to two species (Nile tilapia Oreochromis niloticus and marbled lungfish Protopterus aethiopicus) were lower than baseline estimates in the studied waterbodies. Furthermore, the Lmean in catches for all the stocks were less than the optimum lengths (Lopt), which maximize catches with a minimal impact on biomass and size structure. No significant changes in Lmean, length-frequency distributions, and size at maturity could be attributed to the management changes implemented in 2018, probably because it is too early to observe changes in these parameters. However, there are positive signs attributable to the changes in management as shown by a high proportion of mature individuals in commercial catches for most of the stocks for which the proportion was calculated, and an increase in Lmean and Lmax for some stocks, such as B. docmak, in commercial or experimental catches. New estimates from this study will enhance decision-making and further assessments of fisheries. Routine monitoring is recommended to update and improve the estimates.FUNDING INFORMATION
This work was part of the FishBase for Africa programme funded through a framework agreement between the Royal Museum for Central Africa (RMCA) and the Belgian Development Cooperation and Humanitarian Aid (DGD). The work was executed partly within the KEAFish project (The biodiversity, biogeography, and evolutionary history of the northern basins of the Great African Lakes: the enigmatic fish faunas of lakes Kivu, Edward, and Albert revisited; B2/202/P1/ KeaFish).
ACKNOWLEDGEMENTS
Special thanks are extended to fishers on lakes Edward and George allowed us to sample their catches. We are also grateful to past and present scientists at NaFIRRI who collected the secondary data used in this study. who assisted during fish capture and those on Lake Edward wh
Strength-based approach in social work: professionals' experiences in working with refugee youth in Nakivale refugee settlement, Uganda
Get PDFThe aim of the research was to explore the area of social work practice with refugee youth in
Nakivale refugee settlement, Uganda, in relation to the use of strength-based approach. Hence,
the focus was on the professionals and their experiences in working with the youth, covering the
area of strengths and resources, both personal and those acknowledged in their clients, the
guidelines used and their approach towards youth. Moreover, on a deeper sense, I tried to
observe how professionals’ strengths, values and attitudes are transferred into practice.
The research is constructed around the sensitive contexts of refugee settlements and refugees,
with a focus on the youth and children as predominant groups in the overall population of
refugees in Uganda. The same applies for Nakivale refugee settlement. Within this context and
drawing from social work literature, the strength-based approach has been used as theoretical
framework.
The data was collected through qualitative methods, namely, semi-structured interviews, focus
group discussions and participatory observations, using ethnography as a research design. The
main sample consisted of 25 professionals from 6 organizations active in the settlement, focused
on the work with youth on different areas of practice and service provision (HIJRA –
Humanitarian Initiative Just Relief Aid, War Child Canada, ARC – American Refugee
Committee, FRC – Finnish Refugee Council, Tutapona and Windle Trust Uganda). Therefore a
purposeful sampling was used. Further on, the voices of the youth were captured through FGDs
to enriched the findings. The biggest limitation is the dimension of professionals in relation with
social work, since the field of practice includes different areas connected to social work,
humanitarian and social sciences.
The findings show that the strength-based approach is being used by professionals in their
practices. Hence, it is reflected through their attitude towards their clients, through their values,
motivations and their passion expressed both for work and humanity. They own the necessary
strengths, resources and qualities in order to overcome both personal and work related
challenges. Professionals are able to recognize the strengths and resources of their clients and
promote them. Emphasizes are made on strong and positive attitudes, genuine relationships, faith
and spirituality as a resource and the strength encountered in love, hope and dreams.
Reflections made on refugee youth highlight that they are acknowledged as resourceful and
resilient. The youth voices are strengthening and confirming the findings. Hence, I conclude that
the strength-based approach as a whole is being used by professionals in their practice with the
refugees and refugee youth and at a macro level, the aim of self-reliance policies follows the
same direction
Strength-based approach in social work: professionals' experiences in working with refugee youth in Nakivale refugee settlement, Uganda
Get PDFThe aim of the research was to explore the area of social work practice with refugee youth in
Nakivale refugee settlement, Uganda, in relation to the use of strength-based approach. Hence,
the focus was on the professionals and their experiences in working with the youth, covering the
area of strengths and resources, both personal and those acknowledged in their clients, the
guidelines used and their approach towards youth. Moreover, on a deeper sense, I tried to
observe how professionals’ strengths, values and attitudes are transferred into practice.
The research is constructed around the sensitive contexts of refugee settlements and refugees,
with a focus on the youth and children as predominant groups in the overall population of
refugees in Uganda. The same applies for Nakivale refugee settlement. Within this context and
drawing from social work literature, the strength-based approach has been used as theoretical
framework.
The data was collected through qualitative methods, namely, semi-structured interviews, focus
group discussions and participatory observations, using ethnography as a research design. The
main sample consisted of 25 professionals from 6 organizations active in the settlement, focused
on the work with youth on different areas of practice and service provision (HIJRA –
Humanitarian Initiative Just Relief Aid, War Child Canada, ARC – American Refugee
Committee, FRC – Finnish Refugee Council, Tutapona and Windle Trust Uganda). Therefore a
purposeful sampling was used. Further on, the voices of the youth were captured through FGDs
to enriched the findings. The biggest limitation is the dimension of professionals in relation with
social work, since the field of practice includes different areas connected to social work,
humanitarian and social sciences.
The findings show that the strength-based approach is being used by professionals in their
practices. Hence, it is reflected through their attitude towards their clients, through their values,
motivations and their passion expressed both for work and humanity. They own the necessary
strengths, resources and qualities in order to overcome both personal and work related
challenges. Professionals are able to recognize the strengths and resources of their clients and
promote them. Emphasizes are made on strong and positive attitudes, genuine relationships, faith
and spirituality as a resource and the strength encountered in love, hope and dreams.
Reflections made on refugee youth highlight that they are acknowledged as resourceful and
resilient. The youth voices are strengthening and confirming the findings. Hence, I conclude that
the strength-based approach as a whole is being used by professionals in their practice with the
refugees and refugee youth and at a macro level, the aim of self-reliance policies follows the
same direction
The changing ecosystem of East Africa’s Mare Nostrum: Using ichthyology collections to identify the changes in the Lake Victoria region
No full textThe East African lakes of the Lake Victoria region are vital in providing food, water and transportation to one of the continent’s most densely populated regions. These lakes, which besides Lake Victoria also contain lakes Edward, George, Albert and Kivu all support productive inland fisheries. Additionally, they are biodiversity hotspots that harbour over 700 species of endemic fishes. The majority of these belong to the genus Haplochromis, which radiated in each of these lakes in situ through explosive speciation. Because of these radiations, these lakes have served as natural laboratories in speciation research, resulting in extensive collections that are currently housed in natural history museums. Human interference has led to severe ecosystem degradation in many of these lakes. An example hereof is provided by the fishery of lakes Edward and George, which used to be almost entirely focussed on Nile Tilapia, Oreochromis niloticus. Catches of this species have dwindled to the extent that it is currently only the third-most fished species in these lakes. Using collections, we can investigate whether this change in community structure coincided with a change in trophic preferences in the fisheries target species. However, nowhere were ecosystem changes as profound as in Lake Victoria. Here, a combination of invasive species and eutrophication led to an ecosystem turnover in the 1980’s in which a complex ecosystem with many trophic interactions shifted into a simple one with a strong top-down control exerted by the invasive Nile Perch. However, there is still debate whether this change was caused by the introduction of the Nile Perch, Lates niloticus, or whether it was eutrophication that changed the ecosystem. To investigate this, we used museum collections of fishes that were compiled before and after the changes in the ecosystem occurred. We used parasites as proxies of ecosystem complexity using both collections of Lake Victoria proper as well of those of the neighbouring lakes where these stressors are naturally present. This approach allowed us to use a time-for-space approach with Nile perch being native to Lake Albert, Lake George being naturally eutrophic, while Lake Edward being most similar to historic Lake Victoria. Finally, we investigated the origin of the invasive Nile Perch by comparing specimens from Lake Victoria with those of the (potential) source populations in Lake Albert and Lake Turkana
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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