71 research outputs found
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Mesoscale movement and recursion behaviors of Namibian black rhinos.
Background:Understanding rhino movement behavior, especially their recursive movements, holds significant promise for enhancing rhino conservation efforts, and protecting their habitats and the biodiversity they support. Here we investigate the daily, biweekly, and seasonal recursion behavior of rhinos, to aid conservation applications and increase our foundational knowledge about these important ecosystem engineers. Methods:Using relocation data from 59 rhinos across northern Namibia and 8 years of sampling efforts, we investigated patterns in 24-h displacement at dawn, dusk, midday, and midnight to examine movement behaviors at an intermediate scale and across daily behavioral modes of foraging and resting. To understand recursion patterns across animals' short and long-term ranges, we built T-LoCoH time use grids to estimate recursive movement by each individual. Comparing these grids to contemporaneous MODIS imagery, we investigated productivity's influence on short-term space use and recursion. Finally, we investigated patterns of recursion within a year's home range, measuring the time to return to the most intensively used patches. Results:Twenty four-hour displacements at dawn were frequently smaller than 24-h displacements at dusk or at midday and midnight resting periods. Recursion analyses demonstrated that short-term recursion was most common in areas of median rather than maximum NDVI values. Investigated across a full year, recursion analysis showed rhinos most frequently returned to areas within 8-21 days, though visits were also seen separated by months likely suggesting seasonality in range use. Conclusions:Our results indicate that rhinos may frequently stay within the same area of their home ranges for days at a time, and possibly return to the same general area days in a row especially during morning foraging bouts. Recursion across larger time scales is also evident, and likely a contributing mechanism for maintaining open landscapes and browsing lawns of the savanna
Translocations as Experiments in the Ecological Resilience of an Asocial Mega-Herbivore
Species translocations are remarkable experiments in evolutionary ecology, and increasingly critical to biodiversity conservation. Elaborate socio-ecological hypotheses for translocation success, based on theoretical fitness relationships, are untested and lead to complex uncertainty rather than parsimonious solutions. We used an extraordinary 89 reintroduction and 102 restocking events releasing 682 black rhinoceros (Diceros bicornis) to 81 reserves in southern Africa (1981â2005) to test the influence of interacting socio-ecological and individual characters on post-release survival. We predicted that the socio-ecological context should feature more prominently after restocking than reintroduction because released rhinoceros interact with resident conspecifics. Instead, an interaction between release cohort size and habitat quality explained reintroduction success but only individuals' ages explained restocking outcomes. Achieving translocation success for many species may not be as complicated as theory suggests. Black rhino, and similarly asocial generalist herbivores without substantial predators, are likely to be resilient to ecological challenges and robust candidates for crisis management in a changing world
Home on the Range: Factors Explaining Partial Migration of African Buffalo in a Tropical Environment
Partial migration (when only some individuals in a population undertake seasonal migrations) is common in many species and geographical contexts. Despite the development of modern statistical methods for analyzing partial migration, there have been no studies on what influences partial migration in tropical environments. We present research on factors affecting partial migration in African buffalo (Syncerus caffer) in northeastern Namibia. Our dataset is derived from 32 satellite tracking collars, spans 4 years and contains over 35,000 locations. We used remotely sensed data to quantify various factors that buffalo experience in the dry season when making decisions on whether and how far to migrate, including potential man-made and natural barriers, as well as spatial and temporal heterogeneity in environmental conditions. Using an information-theoretic, non-linear regression approach, our analyses showed that buffalo in this area can be divided into 4 migratory classes: migrants, non-migrants, dispersers, and a new class that we call âexpandersâ. Multimodel inference from least-squares regressions of wet season movements showed that environmental conditions (rainfall, fires, woodland cover, vegetation biomass), distance to the nearest barrier (river, fence, cultivated area) and social factors (age, size of herd at capture) were all important in explaining variation in migratory behaviour. The relative contributions of these variables to partial migration have not previously been assessed for ungulates in the tropics. Understanding the factors driving migratory decisions of wildlife will lead to better-informed conservation and land-use decisions in this area
Africaâs drylands in a changing world : challenges for wildlife conservation under climate and land-use changes in the greater Etosha landscape
Proclaimed in 1907, Etosha National Park in northern Namibia is an iconic dryland system with a rich history of wildlife conservation and research. A recent research symposium on wildlife conservation in the Greater Etosha Landscape (GEL) highlighted increased concern of how intensification of global change will affect wildlife conservation based on participant responses to a questionnaire. The GEL includes Etosha and surrounding areas, the latter divided by a veterinary fence into large, private farms to the south and communal areas of residential and farming land to the north. Here, we leverage our knowledge of this ecosystem to provide insight into the broader challenges facing wildlife conservation in this vulnerable dryland environment. We first look backward, summarizing the history of wildlife conservation and research trends in the GEL based on a literature review, providing a broad-scale understanding of the socioecological processes that drive dryland system dynamics. We then look forward, focusing on eight key areas of challenge and opportunity for this ecosystem: climate change, water availability and quality, vegetation and fire management, adaptability of wildlife populations, disease risk, human-wildlife conflict, wildlife crime, and human dimensions of wildlife conservation. Using this model system, we summarize key lessons and identify critical threats highlighting future research needs to support wildlife management. Research in the GEL has followed a trajectory seen elsewhere reflecting an increase in complexity and integration across biological scales over time. Yet, despite these trends, a gap exists between the scope of recent research efforts and the needs of wildlife conservation to adapt to climate and land-use changes. Given the complex nature of climate change, in addition to locally existing system stressors, a framework of forward-thinking adaptive management to address these challenges, supported by integrative and multidisciplinary research could be beneficial. One critical area for growth is to better integrate research and wildlife management across land-use types. Such efforts have the potential to support wildlife conservation efforts and human development goals, while building resilience against the impacts of climate change. While our conclusions reflect the specifics of the GEL ecosystem, they have direct relevance for other African dryland systems impacted by global change.DATA ACCESSIBILITY STATEMENT:
Additional information about datasets and reports from the Etosha Ecological Institute can be obtained from Claudine Cloete ([email protected]). Additional information about the literature review can be obtained from Stéphanie Périquet ([email protected]).https://www.elsevier.com/locate/geccoMammal Research InstituteZoology and Entomolog
Why Are Outcomes Different for Registry Patients Enrolled Prospectively and Retrospectively? Insights from the Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF).
Background: Retrospective and prospective observational studies are designed to reflect real-world evidence on clinical practice, but can yield conflicting results. The GARFIELD-AF Registry includes both methods of enrolment and allows analysis of differences in patient characteristics and outcomes that may result. Methods and Results: Patients with atrial fibrillation (AF) and â„1 risk factor for stroke at diagnosis of AF were recruited either retrospectively (nâ=â5069) or prospectively (nâ=â5501) from 19 countries and then followed prospectively. The retrospectively enrolled cohort comprised patients with established AF (for a least 6, and up to 24 months before enrolment), who were identified retrospectively (and baseline and partial follow-up data were collected from the emedical records) and then followed prospectively between 0-18 months (such that the total time of follow-up was 24 months; data collection Dec-2009 and Oct-2010). In the prospectively enrolled cohort, patients with newly diagnosed AF (â€6 weeks after diagnosis) were recruited between Mar-2010 and Oct-2011 and were followed for 24 months after enrolment. Differences between the cohorts were observed in clinical characteristics, including type of AF, stroke prevention strategies, and event rates. More patients in the retrospectively identified cohort received vitamin K antagonists (62.1% vs. 53.2%) and fewer received non-vitamin K oral anticoagulants (1.8% vs . 4.2%). All-cause mortality rates per 100 person-years during the prospective follow-up (starting the first study visit up to 1 year) were significantly lower in the retrospective than prospectively identified cohort (3.04 [95% CI 2.51 to 3.67] vs . 4.05 [95% CI 3.53 to 4.63]; pâ=â0.016). Conclusions: Interpretations of data from registries that aim to evaluate the characteristics and outcomes of patients with AF must take account of differences in registry design and the impact of recall bias and survivorship bias that is incurred with retrospective enrolment. Clinical Trial Registration: - URL: http://www.clinicaltrials.gov . Unique identifier for GARFIELD-AF (NCT01090362)
Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.
BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362
Risk factors for Coronavirus disease 2019 (Covid-19) death in a population cohort study from the Western Cape province, South Africa
Risk factors for coronavirus disease 2019 (COVID-19) death in sub-Saharan Africa and the effects of human immunodeficiency virus (HIV) and tuberculosis on COVID-19 outcomes are unknown. We conducted a population cohort study using linked data from adults attending public-sector health facilities in the
Western Cape, South Africa. We used Cox proportional hazards models, adjusted for age, sex, location, and comorbidities, to examine the associations between HIV, tuberculosis, and COVID-19 death from 1 March to 9 June 2020 among (1) public-sector âactive patientsâ (â„1 visit in the 3 years before March 2020); (2) laboratory-diagnosed COVID-19 cases; and (3) hospitalized COVID-19
cases. We calculated the standardized mortality ratio (SMR) for COVID-19, comparing adults living with and without HIV using
modeled population estimates.Among 3 460 932 patients (16% living with HIV), 22 308 were diagnosed with COVID-19, of whom 625 died. COVID19 death was associated with male sex, increasing age, diabetes, hypertension, and chronic kidney disease. HIV was associated with
COVID-19 mortality (adjusted hazard ratio [aHR], 2.14; 95% confidence interval [CI], 1.70â2.70), with similar risks across strata of
viral loads and immunosuppression. Current and previous diagnoses of tuberculosis were associated with COVID-19 death (aHR,
2.70 [95% CI, 1.81â4.04] and 1.51 [95% CI, 1.18â1.93], respectively). The SMR for COVID-19 death associated with HIV was 2.39
(95% CI, 1.96â2.86); population attributable fraction 8.5% (95% CI, 6.1â11.1)
The role of the councillor and the official in the decision-making process of the municipality
Thesis (MPA)--Stellenbosch University, 2000.ENGLISH ABSTRACT: Local government is a sphere of government which consists of municipalities and
its executive and legislative authority is vested in the respective municipal
councils. The council is responsible for exercising its powers and functions on
behalf of the community it represents and it makes decisions in that regard.
A municipality as an organisation which is comprised of two main components:
on the one hand, the council as a body of elected representatives and, on the other,
officials who have been employed by the council. Whilst it is generally accepted
that it is the function of the council to determine policy and of the officials to
execute the determined policy, it is accepted that in .practice there is a degree of
interfacing between these two functions. It is further accepted that, although there
is a clear distinction between the roles of councillor and official, it is possible that
there may be a degree of misconception about their respective roles.
The purpose of this study was to determine whether councillors and officials have
misconceptions about their roles in the decision-making processes of the
municipality and whether such misconceptions have a negative impact on service
delivery.
The research was initiated by a study of decision making in general, followed by a
study of decision making in local government in order to establish a basis for the
field of study. Oostenberg Municipality was then analysed, with specific reference
to its decision-making systems as well as its macro-organisational structure. A
questionnaire was sent to the top structure of the council as well as the top management structure of the municipality; the views of these respondents were
used to determine whether there were any misconceptions about their roles.
The study found that the councillor study group presented a 30.56% degree of
misconception about their role as councillors in the decision-making process of
the municipality, and in the case of the top management structure there was a
29.86% degree of misconception. The study further established that this degree of
misconception impacted negatively on service delivery.
In VIew of the above, it is recommended that councillors be subjected to
appropriate training, that the political party caucuses be accommodated in the
formal decision-making process of the municipality, and that members of the top
management structure be subjected to dedicated training on their role in the
decision-making processes of the municipality. It is also recommended that the
top management structure of the municipality should be in possession of
appropriate academic qualifications.AFRIKAANSE OPSOMMING: Plaaslike Regering is 'n sfeer van regering wat uit munisipaliteite bestaan en ten opsigte
waarvan sy uitvoerende en wetgewende gesag in sy munisipale raad gesetel is. Die raad
is namens die gemeenskap wat hy verteenwoordig vir die uitoefening van sy magte en
funksies verantwoordelik en neem hy besluite in daardie verband.
'n Munisipaliteit as 'n organisasie bestaan uit twee komponente, te wete die raad as 'n
liggaam van verkose verteenwoordigers aan die een kant, en aan die ander kant,
amptenare wat deur die raad in diens geneem is. Terwyl dit algemeen aanvaar word dat
dit die raad se funksie is om beleid te bepaal en dit die amptenare se funksie is om die
uitvoering aan die gestelde beleid te gee, word daar ook aanvaar dat daar in die praktyk,
'n mate van interfase tussen hierdie twee funksies bestaan. Dit word voorts aanvaar dat
terwyl daar 'n duidelike onderskeid tussen die onderskeie rolle van raadslid en amptenaar
is, dit moontlik is dat daar 'n mate van wanbegrip van hul onderskeie rolle bestaan.
Die doel van hierdie studie was om te bepaal of raadslede en amptenare wanbegrip van
hul onderskeie rolle in die besluitnemingsproses van die munisipaliteit ervaar en of
sodanige wanbegrip 'n negatiewe impak op dienslewering het.
Om as basis vir die studieveld te dien is algemene besluitneming eerstens bestudeer,
gevolg deur 'n studie van besluitneming in plaaslike regering. 'n Ontleding van
Oostenberg munisipaliteit met spesifieke verwysing na sy besluitnemingsprosesse en
makro-organisatoriese struktuur is daarna uitgevoer. 'n Vraelys met as respondente die
topstruktuur van die raad sowel as die top bestuurstruktuur van die munisipaliteit was
aangewend om te bepaal of daar 'n mate van wanbegrip van onderskeie rolle bestaan. Die studie het bevind dat die raadslid studiegroep 'n graad van wanbegrip van 30.56%
ten opsigte van sy rol as raadslid in die besluitnemingsproses van die munisipaliteit toon,
en in die geval van die top bestuurstruktuur, is 'n graad van wanbegrip van 29.86%
aangetoon. Die studie het verder bevind dat die bepaalde graad van wanbegrip, negatief
op dienslewering impakteer.
Met inagneming van die voorafgaande is daar aanbeveel dat raadslede aan toepaslike
opleiding blootgestel word, die akkommodering van die politieke party koukusse in die
formele besluitnemingsprosesse van die munisipaliteit, sowel as die toepaslike opleiding
van die lede van die top bestuurstruktuur van die munisipaliteit ten opsigte van hul rol in
die besluitnemingsprosesse van die munisipaliteit. Daar is ook aanbeveel dat die lede van
die top bestuurstruktuur van die munisipaliteit oor toepaslike akademiese kwalifikasies
behoort te beskik
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