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1.
Nat Commun ; 15(1): 549, 2024 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-38263406

RESUMO

Temperature is a fundamental driver of species distribution and ecosystem functioning. Yet, our knowledge of the microclimatic conditions experienced by organisms inside tropical forests remains limited. This is because ecological studies often rely on coarse-gridded temperature estimates representing the conditions at 2 m height in an open-air environment (i.e., macroclimate). In this study, we present a high-resolution pantropical estimate of near-ground (15 cm above the surface) temperatures inside forests. We quantify diurnal and seasonal variability, thus revealing both spatial and temporal microclimate patterns. We find that on average, understory near-ground temperatures are 1.6 °C cooler than the open-air temperatures. The diurnal temperature range is on average 1.7 °C lower inside the forests, in comparison to open-air conditions. More importantly, we demonstrate a substantial spatial variability in the microclimate characteristics of tropical forests. This variability is regulated by a combination of large-scale climate conditions, vegetation structure and topography, and hence could not be captured by existing macroclimate grids. Our results thus contribute to quantifying the actual thermal ranges experienced by organisms inside tropical forests and provide new insights into how these limits may be affected by climate change and ecosystem disturbances.


Assuntos
Ecossistema , Florestas , Temperatura , Mudança Climática , Sistemas Computacionais
2.
Sci Total Environ ; 874: 162560, 2023 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-36870488

RESUMO

Impacts of land cover conversion have been studied well from the top-of-canopy level using satellite observations. Yet, the warming or cooling impacts of land cover and management change (LCMC) from below-canopy level remain less explored. Here, we studied the below-canopy temperature change from field to landscape level across multiple LCMC in southeastern Kenya. To study this, in situ microclimate sensors, satellite observations, and high-resolution below-canopy temperature modelling approaches were used. Our results show that from field to landscape scale, forest to cropland conversion, followed by thicket to cropland change, generate higher surface temperature warming than other conversion types. At field scale, tree loss increases the mean soil temperature (measured at 6 cm below ground) more than the mean below-canopy surface temperature but its impact on the diurnal temperature range was higher on surface temperature than soil temperature in both forest to cropland and thicket to cropland/grassland conversions. At landscape scale, compared with top-of-canopy land surface temperature warming, which was estimated at Landsat overpass time (∼10:30 a.m.), forest to cropland conversion generates ∼3 °C higher below-canopy surface temperature warming. Land management change, through fencing of wildlife conservation areas and limiting mobility of mega browsers, can have an impact on woody cover and induce more below-canopy surface temperature warming than top-of-canopy in comparison with non-conservancy areas. These results indicate that human induced land changes can generate more below-canopy warming than inferred from top-of-canopy satellite observations. Together, the results highlight the importance of considering the climatic impacts of LCMC from both top-of-canopy and below-canopy level for effective mitigation of anthropogenic warming from land surface changes.

3.
J Blood Med ; 13: 275-282, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35651987

RESUMO

Background: Thrombocytopenia is a worldwide public health problem in pregnant women and is associated with significant maternal-fetal complications and mortality. Determination of burden, severity, and predictors of thrombocytopenia in pregnant women is imperative to develop intervention measures to mitigate their risk and public health impact, which is not well known in Ethiopia, particularly in the selected study area. Thus, this study aimed to determine the burden, severity, and predictors of thrombocytopenia among pregnant women in Wolkite University Specialized Hospital, southwest Ethiopia. Materials and Methods: A cross-sectional study was employed among 422 pregnant women from May to August 2021. A structured questionnaire was used to collect data on socio-demographic, reproductive, and related characteristics. Venous blood samples were collected and platelet counts were determined by Sysmex XP-300 hematology analyzer. A binary logistic regression analysis was performed using SPSS version 22 software to identify independent predictors of thrombocytopenia. The p-value <0.05 was considered statistically significant. Results: The overall burden of thrombocytopenia among pregnant women was 14.5% (95% CI: 11.4-17.8). Among them, 77%, 16.4%, and 6.6% had mild, moderate, and severe thrombocytopenia, respectively. Rural residence (AOR: 2.9, 95% CI: 1.5-5.8), increasing age (AOR: 1.9, 95% CI: 1.04-3.44), alcohol consumption (AOR: 2.48, 95% CI: 1.3-4.5), and HIV infection (AOR: 8.5, 95% CI: 1.9-18.4) were independent predictors of thrombocytopenia among the pregnant women. Conclusion: A high burden of thrombocytopenia (14.5%) was observed among the pregnant women in this study area. Rural residence, increasing age, consumption of alcohol, and HIV infection were identified as independent predictors of thrombocytopenia. The findings of this study should be taken into consideration to conduct appropriate intervention measures on identified predictors and implement routine screening of platelet count, thrombocytopenia diagnosis, and treatments to reduce the burden of morbidity and mortality among pregnant women.

4.
Proc Natl Acad Sci U S A ; 118(7)2021 02 16.
Artigo em Inglês | MEDLINE | ID: mdl-33558246

RESUMO

In the Amazon rainforest, land use following deforestation is diverse and dynamic. Mounting evidence indicates that the climatic impacts of forest loss can also vary considerably, depending on specific features of the affected areas. The size of the deforested patches, for instance, was shown to modulate the characteristics of local climatic impacts. Nonetheless, the influence of different types of land use and management strategies on the magnitude of local climatic changes remains uncertain. Here, we evaluated the impacts of large-scale commodity farming and rural settlements on surface temperature, rainfall patterns, and energy fluxes. Our results reveal that changes in land-atmosphere coupling are induced not only by deforestation size but also, by land use type and management patterns inside the deforested areas. We provide evidence that, in comparison with rural settlements, deforestation caused by large-scale commodity agriculture is more likely to reduce convective rainfall and increase land surface temperature. We demonstrate that these differences are mainly caused by a more intensive management of the land, resulting in significantly lower vegetation cover throughout the year, which reduces latent heat flux. Our findings indicate an urgent need for alternative agricultural practices, as well as forest restoration, for maintaining ecosystem processes and mitigating change in the local climates across the Amazon basin.


Assuntos
Agricultura/estatística & dados numéricos , Processos Climáticos , Conservação dos Recursos Naturais/estatística & dados numéricos , Ecossistema
5.
Sci Total Environ ; 717: 137255, 2020 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-32084691

RESUMO

Bushlands (Acacia-Commiphora) constitute the largest and one of the most threatened ecosystems in East Africa. Although several studies have investigated the climatic impacts of land changes on local and global climate, the main focus has been on forest loss and the impacts of bushland clearing thus remain poorly understood. Measuring the impacts of bushland loss on local climate is challenging given that changes often occur at fragmented and small patches. Here, we apply high-resolution satellite imagery and land surface flux modeling approaches to unveil the impacts of bushland clearing on surface biophysical properties and its associated effects on surface energy balance and land surface temperature. Our results show that bushland clearing leads to an average reduction in evapotranspiration of 0.4 mm day-1. The changes in surface biophysical properties affected the surface energy balance components with different magnitude. The reduction in latent heat flux was stronger than other surface energy fluxes and resulted in an average net increase in daytime land surface temperature (LST) of up to 1.75 K. These results demonstrate the important impact of bushland-to-cropland conversion on the local climate, as they reveal increases in LST of a magnitude comparable to those caused by forest loss. This finding highlights the necessity of bushland conservation for regulating the land surface temperature in East Africa and, at the same time, warns of the climatic impacts of clearing bushlands for agriculture.


Assuntos
Produtos Agrícolas , África Oriental , Florestas , Imagens de Satélites
6.
Vet Med Int ; 2018: 5729296, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29977494

RESUMO

Contagious bovine pleuropneumonia (CBPP) is a highly contagious disease of cattle which is one of the great plagues which continues to devastate the cattle herds on which so many people are dependent in Africa. Cross-sectional study was conducted from October 2015 to August 2016 to determine the seroprevalence of CBPP in cattle and associated risk factors in Gimbo district, Southwest Ethiopia. A total of 384 serum samples were collected and tested for the presence of specific antibodies against Mycoplasma mycoides subspecies mycoides small colony (MmmSC), using a competitive enzyme-linked immunosorbent assay (cELISA). Univariable and multivariable logistic regression analysis were performed to determine the association between risk factors and seroprevalence of CBPP. An overall seroprevalence of CBPP was 8.1% (31/384) and it was ranging from 0% to 20% across different Peasant associations (PAs). The seroprevalence of CBPP among adult animals was 8.5% (25) and in young 6.6% (6), in good body condition animals 6.6% (18) and in poor 11.5% (13), in dry season 11.9% (20) and in rainy 5.1% (11), and in highland altitude 2.5% (3), midland 3.8% (5), and lowland 17.4% (23). Among the potential predisposing factors assessed, altitude was found significantly (p = 0.02, OR = 7.3) associated with the seroprevalence of contagious bovine pleuropneumonia and other risk factors had no significant (P > 0.05) influence. The present study showed that the overall seroprevalence of CBPP in Gimbo district was high and this indicates a need for intervening and implementing control measures to prevent further spread of the disease in the district through the use of better and coordinated vaccination program.

7.
BMC Res Notes ; 11(1): 112, 2018 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-29422081

RESUMO

OBJECTIVE: The status of bluetongue disease, vectors for transmission of the disease and the serotypes involved are not clearly known in Ethiopia. This sero-epidemiological study was conducted to determine the seroprevalence and associated risk factors of bluetongue in small ruminants of South Western Ethiopia. RESULT: 422 serum samples were screened for the presence of bluetongue virus (BTV) specific antibodies using competitive enzyme-linked immunosorbent assay (c-ELISA) and 30.6% (129/422) (confidence interval CI 26.2-35%) of the sheep and goat serum samples were found positive. Multivariate analysis of several risk factors like age, sex, altitude, body condition and species of animals were studied and it was observed that species of animals, age and altitude had significant influence (P < 0.05) on seropositivity to BTV. Goats showed more seropositivity to bluetongue as compared to sheep [AOR = 2.4, 95% CI (1.5-3.9), P = 0.001], adult animals were more seropositive [AOR = 3.1, 95% CI (1.9-5.1), P = 0.001] than other age groups and animals at the lowland [AOR = 3.1, 95% CI (1.5-6.4), P = 0.002] showed more seropositivity to bluetongue than midland and high land. Sex and body condition of the animals had no statistically significant (P > 0.05) effect on seropositivity to bluetongue.


Assuntos
Vírus Bluetongue/imunologia , Bluetongue/sangue , Doenças das Cabras/sangue , Fatores Etários , Animais , Bluetongue/epidemiologia , Estudos Transversais , Etiópia/epidemiologia , Feminino , Doenças das Cabras/epidemiologia , Cabras , Masculino , Estudos Soroepidemiológicos , Ovinos
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