112 research outputs found
Perceptions of rule-breaking related to marine ecosystem health
Finding effective solutions to manage marine resources is high on political and conservation agendas worldwide. This is made more urgent by the rate of increase in the human population and concomitant resource pressures in coastal areas. This paper links empirical socio-economic data about perceptions of marine resource health to the breaking of marine management rules, using fisheries as a case study. The relationship between perceived rule-breaking (non-compliance with regulations controlling fishing) and perceived health of inshore marine environments was investigated through face-to-face interviews with 299 heads of households in three Tanzanian coastal communities in November and December 2011. Awareness of rules controlling fishing activity was high among all respondents. Fishers were able to describe more specific rules controlling fishing practices than non-fishers (t = 3.5, df = 297, p < 0.01). Perceived breaking of fishing regulations was reported by nearly half of all respondents, saying “some” (32% of responses) or “most” (15% of responses) people break fishing rules. Ordinal regression modelling revealed a significant linkage (z = −3.44, p < 0.001) in the relationship between respondents' perceptions of deteriorating marine health and their perception of increased rule-breaking. In this paper, inferences from an empirical study are used to identify and argue the potential for using perceptions of ecosystem health and level of rule-breaking as a means to guide management measures. When considering different management options (e.g. Marine Protected Areas), policy makers are advised to take account of and utilise likely egoistic or altruistic decision-making factors used by fishers to determine their marine activities
Spatial patterns of zooplankton distribution and abundance in relation to phytoplankton, fish catch and some water quality parameters at Shirati bay, lake victoria-Tanzania
Spatial patterns and abundance of zooplankton in aquatic habitats are important determinants for production of fish species, invertebrates and availability of phytoplankton. Weekly monitoring for zooplankton abundance was conducted in Shirati Bay, Lake Victoria, to explore their spatial patterns in relation to phytoplankton, fish catch and some water quality parameters. The vertical distribution of zooplankton was generally higher close to the bottom as compared to surface waters of the lake. Zooplankton vertical distribution positively correlated with water transparency (r = 0.680, p = 0.011). The horizontal abundance of zooplankton was not significantly different amongst the three stations (p = 0.5143). While Copepoda was the dominant group in terms of composition, Rotifera had the highest diversity indices of all the zooplankton groups obtained. The abundance of nauplius larvae was significantly higher than that of the copepodites (p = 0.022). Nile perch, Lates niloticus dominated the total catches (47%) followed by Nile tilapia, Oreochromis niloticus (29%) and haplochromines (21%). The abundance of haplochromines and juvenile fishes correlated significantly with the abundance of zooplankton (r = 0.856, p = 0.002 and r = 0.58, p = 0.038, respectively). The current study revealed that zooplankton vertical distribution at Shirati Bay is mainly controlled by water transparency and predation by juvenile Nile perch, Nile tilapia and haplochromines.Keywords: chlorophyll-a; calanoid; cyclopoid; nauplius larvae; juvenile fis
The Arclight Ophthalmoscope: A Reliable Low-Cost Alternative to the Standard Direct Ophthalmoscope.
Background. The Arclight ophthalmoscope is a low-cost alternative to standard direct ophthalmoscopes. This study compared the Arclight ophthalmoscope with the Heine K180 direct ophthalmoscope to evaluate its reliability in assessing the vertical cup disc ratio (VCDR) and its ease of use (EOU). Methods. Eight medical students used both the Arclight and the Heine ophthalmoscopes to examine the optic disc in 9 subjects. An EOU score was provided after every examination (a higher score indicating that the ophthalmoscope is easier to use). A consultant ophthalmologist provided the reference standard VCDR. Results. 288 examinations were performed. The number of examinations that yielded an estimation of the VCDR was significantly higher for the Arclight ophthalmoscope (125/144, 85%) compared to the Heine ophthalmoscope (88/144, 61%) (p < 0.001). The mean difference from the reference standard VCDR was similar for both instruments, with a mean of -0.078 (95% CI: -0.10 to -0.056) for the Arclight and -0.072 (95% CI: -0.097 to -0.046) for Heine (p = 0.69). The overall EOU score was significantly higher for the Arclight ophthalmoscope (p < 0.001). Conclusion. The Arclight ophthalmoscope performs as well as, and is easier to use than, a standard direct ophthalmoscope, suggesting it is a reliable, low-cost alternative
Fisheries Statistics for Lake Victoria, Tanzania
This research article published by Springer Nature Switzerland AG., 2017Time series fisheries statistics data mainly from Frame Surveys, Catch Assessment Surveys and Fisheries Annual Statistics Reports for Lake Victoria from 1967–2016 were collected from the Fisheries Development Division in Tanzania. These surveys and reports comprised relevant information and data on fish catches and fishing effort. The data were analysed and used to describe variations and trends in the number of fishers, number of fishing crafts, fish weight, catch per boat, total number of gillnets, beach seines, longline hooks, outboard and inboard engines. Frame Survey results showed an increasing trend in the number of fishers and fishing crafts, with the highest number of fishers and fishing crafts being 109,397 and 31,773, respectively in 2016. Longline hooks increased from 2,200,901 in 2000 to 8,163,119 hooks in 2016. In general, the catch per unit effort (CPUE) for all species was high at 39 mt/boat/year in 1967 and decreased to 8 mt/boat/year in 2014. However, CPUE for Lates niloticus has increased since the late 1980s, with the highest CPUE of 19.22 mt/boat/year being recorded in 1995, and from 2000 it decreased gradually to 7 mt/boat/year in 2014. As the fisheries statistics show an increase in fishing pressure over the years, it is evident that there is a sign of overfishing. For that matter, effective fisheries management is needed for the three riparian states to safeguard the sustainable use of fishery resources in the lake and to provide data that can be used in the evaluation of the fisheries objectives
Comparative performance of three experimental hut designs for measuring malaria vector responses to insecticides in Tanzania.
BACKGROUND: Experimental huts are simplified, standardized representations of human habitations that provide model systems to evaluate insecticides used in indoor residual spray (IRS) and long-lasting insecticidal nets (LLINs) to kill disease vectors. Hut volume, construction materials and size of entry points impact mosquito entry and exposure to insecticides. The performance of three standard experimental hut designs was compared to evaluate insecticide used in LLINs. METHODS: Field studies were conducted at the World Health Organization Pesticide Evaluation Scheme (WHOPES) testing site in Muheza, Tanzania. Three East African huts, three West African huts, and three Ifakara huts were compared using Olyset(®) and Permanet 2.0(®) versus untreated nets as a control. Outcomes measured were mortality, induced exophily (exit rate), blood feeding inhibition and deterrence (entry rate). Data were analysed using linear mixed effect regression and Bland-Altman comparison of paired differences. RESULTS: A total of 613 mosquitoes were collected in 36 nights, of which 13.5% were Anopheles gambiae sensu lato, 21% Anopheles funestus sensu stricto, 38% Mansonia species and 28% Culex species. Ifakara huts caught three times more mosquitoes than the East African and West African huts, while the West African huts caught significantly fewer mosquitoes than the other hut types. Mosquito densities were low, very little mosquito exit was measured in any of the huts with no measurable exophily caused by the use of either Olyset or Permanet. When the huts were directly compared, the West African huts measured greater exophily than other huts. As unholed nets were used in the experiments and few mosquitoes were captured, it was not possible to measure difference in feeding success either between treatments or hut types. In each of the hut types there was increased mortality when Permanet or Olyset were present inside the huts compared to the control, however this did not vary between the hut types. CONCLUSIONS: Both East African and Ifakara huts performed in a similar way although Ifakara huts allowed more mosquitoes to enter, increasing data power. The work convincingly demonstrates that the East African huts and Ifakara huts collect substantially more mosquitoes than the West African huts
Fetal Hemoglobin is Associated with Peripheral Oxygen Saturation in Sickle Cell Disease in Tanzania.
Fetal hemoglobin (HbF) and peripheral hemoglobin oxygen saturation (SpO2) both predict clinical severity in sickle cell disease (SCD), while reticulocytosis is associated with vasculopathy, but there are few data on mechanisms. HbF, SpO2 and routine clinical and laboratory measures were available in a Tanzanian cohort of 1175 SCD individuals aged≥5years and the association with SpO2 (as response variable transformed to a Poisson distribution) was assessed by negative binomial model with age and sex as covariates. Increase in HbF was associated with increased SpO2 (rate ratio, RR=1.19; 95% confidence intervals [CI] 1.04, 1.37 per natural log unit of HbF; p=0.0004). In univariable analysis, SpO2 was inversely associated with age, reticulocyte count, and log (total bilirubin) and directly with pulse, SBP, hemoglobin, and log(HbF). In multivariable regression log(HbF) (RR 1.191; 95%CI 1.04, 1.37; p=0.013), pulse (RR 1.01; 95%CI 1.00, 1.01; p=0.026), SBP (RR 1.008; 95%CI 1.00, 1.02; p=0.014), and hemoglobin (1.120; 95%CI 1.05, 1.19; p=0.001) were positively and independently associated with SpO2 while reticulocyte count (RR 0.985; 95%CI 0.97, 0.99; p=0.019) was independently inversely associated with SpO2. In SCD, improving SpO2, in part through cardiovascular compensation and associated with reduced reticulocytosis, may be a mechanism by which HbF reduces disease severity
Africa
Africa is one of the lowest contributors to greenhouse gas
emissions causing climate change, yet key development sectors have already experienced widespread losses and damages attributable to human-induced climate change, including biodiversity loss, water shortages, reduced food production, loss of lives and reduced economic growth (high confidence1).//
Between 1.5°C and 2°C global warming—assuming localised
and incremental adaptation—negative impacts are projected
to become widespread and severe with reduced food
production, reduced economic growth, increased inequality
and poverty, biodiversity loss, increased human morbidity
and mortality (high confidence). Limiting global warming
to 1.5°C is expected to substantially reduce damages to
African economies, agriculture, human health, and ecosystems
compared to higher levels of global warming (high confidence).//
Exposure and vulnerability to climate change in Africa
are multi-dimensional with socioeconomic, political and
environmental factors intersecting (very high confidence).
Africans are disproportionately employed in climate-exposed sectors: 55–62% of the sub-Saharan workforce is employed in agriculture and 95% of cropland is rainfed. In rural Africa, poor and female-headed households face greater livelihood risks from climate hazards. In urban areas, growing informal settlements without basic services increase
the vulnerability of large populations to climate hazards, especially women, children and the elderly. //
Adaptation in Africa has multiple benefits, and most assessed adaptation options have medium effectiveness at reducing risks for present-day global warming, but their efficacy at future warming levels is largely unknown (high confidence)./
Certified community forests positively impact human wellbeing and conservation effectiveness and improve the performance of nearby national protected areas
Community forests (CFs) aim to improve human wellbeing and conservation effectiveness, though their performance remains contested. A recent innovation in protected area (PA) governance is to combine CFs with forest certification. We assess (1) the impact of certified CFs on wellbeing and conservation effectiveness; (2) gender inequality and elite capture; (3) interaction effects with neighboring national PAs. We used a novel approach that integrates field data consisting of locally identified indicators representative of multidimensional wellbeing, with remotely sensed data on conservation effectiveness and statistical matching to improve causal inference. We found that CFs positively impacted wellbeing, conservation effectiveness, and reduced gender inequality, though they did not reduce elite capture. We also detected positive interaction effects between certified CFs and neighboring national PAs. Our findings suggest that locating contrasting local and national PA governance approaches next to each other may help to maximize wellbeing and conservation benefits within complex multiuse landscapes
Role of human Pegivirus infections in whole; Plasmodium falciparum; sporozoite vaccination and controlled human malaria infection in African volunteers
BACKGROUND: Diverse vaccination outcomes and protection levels among different populations pose a serious challenge to the development of an effective malaria vaccine. Co-infections are among many factors associated with immune dysfunction and sub-optimal vaccination outcomes. Chronic, asymptomatic viral infections can contribute to the modulation of vaccine efficacy through various mechanisms. Human Pegivirus-1 (HPgV-1) persists in immune cells thereby potentially modulating immune responses. We investigated whether Pegivirus infection influences vaccine-induced responses and protection in African volunteers undergoing whole P. falciparum sporozoites-based malaria vaccination and controlled human malaria infections (CHMI). METHODS: HPgV-1 prevalence was quantified by RT-qPCR in plasma samples of 96 individuals before, post vaccination with PfSPZ Vaccine and after CHMI in cohorts from Tanzania and Equatorial Guinea. The impact of HPgV-1 infection was evaluated on (1) systemic cytokine and chemokine levels measured by Luminex, (2) PfCSP-specific antibody titers quantified by ELISA, (3) asexual blood-stage parasitemia pre-patent periods and parasite multiplication rates, (4) HPgV-1 RNA levels upon asexual blood-stage parasitemia induced by CHMI. RESULTS: The prevalence of HPgV-1 was 29.2% (28/96) and sequence analysis of the 5' UTR and E2 regions revealed the predominance of genotypes 1, 2 and 5. HPgV-1 infection was associated with elevated systemic levels of IL-2 and IL-17A. Comparable vaccine-induced anti-PfCSP antibody titers, asexual blood-stage multiplication rates and pre-patent periods were observed in HPgV-1 positive and negative individuals. However, a tendency for higher protection levels was detected in the HPgV-1 positive group (62.5%) compared to the negative one (51.6%) following CHMI. HPgV-1 viremia levels were not significantly altered after CHMI. CONCLUSIONS: HPgV-1 infection did not alter PfSPZ Vaccine elicited levels of PfCSP-specific antibody responses and parasite multiplication rates. Ongoing HPgV-1 infection appears to improve to some degree protection against CHMI in PfSPZ-vaccinated individuals. This is likely through modulation of immune system activation and systemic cytokines as higher levels of IL-2 and IL17A were observed in HPgV-1 infected individuals. CHMI is safe and well tolerated in HPgV-1 infected individuals. Identification of cell types and mechanisms of both silent and productive infection in individuals will help to unravel the biology of this widely present but largely under-researched virus
Synthesis of bifunctional monomers by the palladium-catalyzed carbonylation of cardanol and its derivatives
The authors thank the Royal Society Leverhulme Africa Program for funding this project.A 1,2-bis(di-tert-butylphosphinomethyl)benzene-modified palladium catalyst has been used to synthesize bifunctional monomers of different chain lengths from cardanol. Short-chain derivatives of cardanol, such as (E)-3-(dodec-8-enyl)phenol; HOPhC12-ene, (E)-3-(undec-8-enyl)phenol; HOPhC11-ene, (E)-3-(dec-8-enyl)phenol; HOPhC10-ene, and 3-(non-8-enyl)phenol; HOPhC9-ene, were synthesized by the metathesis of cardanol with symmetrical internal alkenes. These derivatives were methoxycarbonylated to produce monomers with different chain lengths such as methyl-16-(3-hydroxyphenyl)hexadecanoate; HOPhC15COOMe, methyl-13-(3-hydroxyphenyl)tridecanoate; HOPhC12COOMe, methyl-12-(3-hydroxyphenyl)dodecanoate; HOPhC11COOMe, methyl-11-(3-hydroxyphenyl)undecanoate; HOPhC10COOMe, and methyl-10-(3-hydroxyphenyl)decanoate; HOPhC9COOMe, respectively. Polymerization of the synthesized monomers produced oligomers that consist of up to seven monomer units as confirmed by MALDI-TOF-MS. Lactone formation was also observed in some cases under polymerization conditions.PostprintPostprintPeer reviewe
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