Soil Carbon Mineralization Kinetics as Influenced by Changes in Land Use and Soil Management in the Central Highlands of Ethiopia

አህፅሮትበመካከለኛው የኢትዮጵያ ደጋማ ቦታዎች የአፈር መብላላት (ሚንራላይዜሽን) ሂደትን ለመረዳት ኩታ ገጠም ከሆኑ 5 የመሬት አጠቃቀምና አያያዝ ዘዴዎች (የግጦሽ መሬት፣ የእርሻ ማሳ፣ ወደ በህር ዛፍ የተቀየረ የእርሻ መሬት፣ በኖራ የታከመ ማሳ እና የእዳሪ ማሳ) በተሰበሰቡ የአፈር ናሙናዎች ላይ 62 ቀናት የፈጀ የቤተ ሙከራ ጥናት ተካሂዷል፡፡ ውጤቱ እንደሚያሳየው የጥቅል ካርቦን መብላላትና እና የመብላላት ፍጥነት ከግጦሽ መሬት በሁለቱም የአፈር ጥልቀት (ከ0-10 ሳ.ሜ እና 10-20 ሳ.ሜ) መጠን ከሌሎች የመሬት  አጠቃቀም ስልቶች አንፃር ሲታይ በተከታታይነት ከፍተኛ ሆኖ ታይቷል፡፡ ጥቅል የካርቦንዳይኦክሳይድ ልቀት ሲታይ የግጦሽ ማሳ፣ የእርሻ ማሳ፣ የባህር ዛፍ ማሳ፣ የእዳሪ መሬት እና በኖራ የታከመ መሬት ቅደም ተከተላቸውን ጠብቀው ከፍተኛ መጠን ነበራቸው፡፡     ከተፈተሹት 6 የፍጥነት ሀይል ሞዴሎች ውስጥ የመጀመሪያ ደረጃው ሞዴል (ጥቅል ካርቦን ልቀት፣ እምቅ ካርቦን) (1-e-kt) የሚባለው የሙከራ አፈሮችን የካርቦን መብላላት መጠን በመግለፅ ረገድ ተመራጭ ሆኗል፡፡ የግጦሽ ማሳ በሁለቱም ጥልቀት ደረጃዎች እና የእርሻ ማሳ በ10- 20 ሳ.ሜ ጥልቀት ከሌሎች የመሬት አጠቃቀም ስልቶች  አንፃር ሲታዩ አመርቂ የሆነ እምቅ ለመብላላት የሚሆን ካርቦን እንዳላቸው ማወቅ ተችሏል፡፡በተመሳሳይ መልኩ ኖራ የተጨመረበት ማሳ እና የእዳሪ መሬት ከ1ዐ-20 ሳ.ሜ የአፈር ጥልቀት ላይ ከሌሎች መሬት አጠቃቀሞችና አያያዝ ስልቶች አንፃር ሲተይ አመርቂ የሆነ ካርቦንዳይኦክሳይድ ነበራቸው፡፡ በሌላ በኩል ደግሞ የግጦሽ ማሳን የአፈር ተፈጥሮአዊ እና ክብደተ-ህያው ካርቦን ይዘት ከኩታ ገጠም የእርሻ ማሳ፣ የባህር ዛፍ መሬት፣ በኖራ የታከመ ማሳ እና በእዳሪ ማሳ አንፃር ሲታይ በ9.9 በመቶ በአስተማማኝ ደረጃ የበለጠ መሆኑ ታይቷል፡፡ የአፈር ተፈጥሮአዊ እና ክብደተ-ህያው ካርቦን መጠን ከእምቅ መብላላት ከሚችል ካርቦን፣ የፍጥነት ኃይል እና የሁለቱ ብዜት ጋር አዎንታዊ ግኑኝነት ሲኖራቸው ከt½ እና qCO2 ጋር ግን አሉታዊ ግኑኝነት እንዳላቸው ለታዉቋል፡፡ ስለሆነም ተአካ፣ ክህካ፣ እሚካ እና qCO2 የመሬት አጠቃቀምና አያያዝ ዘዴዎችን የልዩነት ደረጃ ሁነኛ መለኪያዎች መሆናቸው ታውቋል፡፡ AbstractConversions of natural vegetation to other land use and soil management systems are often accompanied by changes in soil properties and have environmental implications. Such changes in land use and agricultural practices affect soil carbon pools and contribute to increased atmospheric CO2 concentrations. Hence, to understand carbon mineralization processes, a 62-day laboratory incubation experiment was carried out using soil samples collected from five adjacent land uses and management systems (grassland, cropland, Eucalyptus plantations, limed land, and fallow land) in the central highlands of Ethiopia. Total carbon mineralized and the mineralization rates were consistently higher in grasslands in both 0-10 cm and 10-20 cm as compared to the other land uses and management systems. The cumulative CO2 release followed the order: grassland> cropland> Eucalyptus> fallow land> limed land. Among six kinetic models tested, a first-order model [Ct = Co (1-e-kt)] was selected and fitted well to describe C mineralization of the experimental data. Grassland in both depths and cropland in the surface layer (0- 10 cm) had significantly higher mean values of potentially mineralizable carbon (Co) as compared to each depth in different land uses. Metabolic quotient (qCO2) observed in limed land and fallow land in 10 -20 cm depth was significantly higher than the other land uses and management systems. Similarly, soils under grassland had significantly (p<0.001) higher soil organic carbon (SOC) and microbial biomass carbon (MBC) than the adjacent cropland, Eucalyptus plantations, limed land and fallow land. SOC and MBC were positively correlated with Co, k and Co*k, and negatively correlated with t1/2 andqCO2. Hence, SOC, MBC, Co and qCO2 were better discriminators among different land uses and management systems, and therefore, could be used as sensitive indicators of ecosystem change in the study area.

Precision medicine and public health interventions: tuberculosis as a model?

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Birc2/Iap1 regulates endothelial cell integrity and blood vessel homeostasis.

none4noneM. SANTORO; TEMESGEN SAMUEL; TRACY MITCHEL; JOHN C. REED AND DIDIER Y. STAINIERSantoro, Massimo; Temesgen, Samuel; Tracy, Mitchel; JOHN C. REED AND DIDIER Y., Stainie

Large-scale commodity agriculture exacerbates the climatic impacts of Amazonian deforestation

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.Peer reviewe

A comparison of selected parametric and imputation methods for estimating snag density and snag quality attributes

Snags (standing dead trees) are an essential structural component of forests. Because wildlife use of snags depends on size and decay stage, snag density estimation without any information about snag quality attributes is of little value for wildlife management decision makers. Little work has been done to develop models that allow multivariate estimation of snag density by snag quality class. Using climate, topography, Landsat TM data, stand age and forest type collected for 2356 forested Forest Inventory and Analysis plots in western Washington and western Oregon, we evaluated two multivariate techniques for their abilities to estimate density of snags by three decay classes. The density of live trees and snags in three decay classes (D1: recently dead, little decay; D2: decay, without top, some branches and bark missing; D3: extensive decay, missing bark and most branches) with diameter at breast height (DBH) ≥ 12.7 cm was estimated using a nonparametric random forest nearest neighbor imputation technique (RF) and a parametric two-stage model (QPORD), for which the number of trees per hectare was estimated with a Quasipoisson model in the first stage and the probability of belonging to a tree status class (live, D1, D2, D3) was estimated with an ordinal regression model in the second stage. The presence of large snags with DBH ≥ 50 cm was predicted using a logistic regression and RF imputation. Because of the more homogenous conditions on private forest lands, snag density by decay class was predicted with higher accuracies on private forest lands than on public lands, while presence of large snags was more accurately predicted on public lands, owing to the higher prevalence of large snags on public lands. RF outperformed the QPORD model in terms of percent accurate predictions, while QPORD provided smaller root mean square errors in predicting snag density by decay class. The logistic regression model achieved more accurate presence/absence classification of large snags than the RF imputation approach. Adjusting the decision threshold to account for unequal size for presence and absence classes is more straightforward for the logistic regression than for the RF imputation approach. Overall, model accuracies were poor in this study, which can be attributed to the poor predictive quality of the explanatory variables and the large range of forest types and geographic conditions observed in the data.This is the publisher’s final pdf. The published article is copyrighted by Elsevier and can be found at: http://www.journals.elsevier.com/forest-ecology-and-managemen

A comparison of selected parametric and imputation methods for estimating snag density and snag quality attributes

Snags (standing dead trees) are an essential structural component of forests. Because wildlife use of snags depends on size and decay stage, snag density estimation without any information about snag quality attributes is of little value for wildlife management decision makers. Little work has been done to develop models that allow multivariate estimation of snag density by snag quality class. Using climate, topography, Landsat TM data, stand age and forest type collected for 2356 forested Forest Inventory and Analysis plots in western Washington and western Oregon, we evaluated two multivariate techniques for their abilities to estimate density of snags by three decay classes. The density of live trees and snags in three decay classes (D1: recently dead, little decay; D2: decay, without top, some branches and bark missing; D3: extensive decay, missing bark and most branches) with diameter at breast height (DBH) ≥ 12.7 cm was estimated using a nonparametric random forest nearest neighbor imputation technique (RF) and a parametric two-stage model (QPORD), for which the number of trees per hectare was estimated with a Quasipoisson model in the first stage and the probability of belonging to a tree status class (live, D1, D2, D3) was estimated with an ordinal regression model in the second stage. The presence of large snags with DBH ≥ 50 cm was predicted using a logistic regression and RF imputation. Because of the more homogenous conditions on private forest lands, snag density by decay class was predicted with higher accuracies on private forest lands than on public lands, while presence of large snags was more accurately predicted on public lands, owing to the higher prevalence of large snags on public lands. RF outperformed the QPORD model in terms of percent accurate predictions, while QPORD provided smaller root mean square errors in predicting snag density by decay class. The logistic regression model achieved more accurate presence/absence classification of large snags than the RF imputation approach. Adjusting the decision threshold to account for unequal size for presence and absence classes is more straightforward for the logistic regression than for the RF imputation approach. Overall, model accuracies were poor in this study, which can be attributed to the poor predictive quality of the explanatory variables and the large range of forest types and geographic conditions observed in the data.Keywords: Snag size class, Ordinal regression, Snag density, Snag decay class, Nearest neighbor imputatio

Geostatistical modeling of riparian forest microclimate and its implications for sampling

Les modèles de prédiction du microclimat pour différentes conditions de station dans les zones riveraines boisées des cours d’eau de tête de bassin sont peu développés et les procédures d’échantillonnage pour caractériser les gradients sous-jacents du microclimat riverain sont rares. Nous avons utilisé des données de microclimat riverain collectées le long de huit cours d’eau de tête de bassin dans la chaîne côtière de l’Oregon pour comparer le krigeage ordinaire (KO), le krigeage universel (KU) et le krigeage avec dérive externe (KDE) pour la prédiction localisée de la température moyenne maximale de l’air (Tair). Plusieurs caractéristiques topographiques et de la structure de la forêt ont été considérées comme paramètres spécifiques à la station. L’élévation au-dessus du cours d’eau et la distance du cours d’eau étaient les covariables les plus importantes dans les modèles de KDE qui donnaient de meilleurs résultats que le KO et le KU en termes d’écart-type. La répartition des échantillons a été optimisée sur la base de la variance de krigeage et des moyennes pondérées du critère de la plus courte distance à l’aide d’un algorithme de recuit simulé. La répartition optimisée des échantillons donnait de meilleurs résultats que la répartition systématique en termes de variance moyenne de krigeage, surtout lorsque le nombre d’échantillons était faible. Ces résultats suggèrent des méthodes pour augmenter l’efficacité du suivi du microclimat dans les zones riveraines.Predictive models of microclimate under various site conditions in forested headwater stream – riparian areas are poorly developed, and sampling designs for characterizing underlying riparian microclimate gradients are sparse. We used riparian microclimate data collected at eight headwater streams in the Oregon Coast Range to compare ordinary kriging (OK), universal kriging (UK), and kriging with external drift (KED) for point prediction of mean maximum air temperature (T air). Several topographic and forest structure characteristics were considered as site-specific parameters. Height above stream and distance to stream were the most important covariates in the KED models, which outperformed OK and UK in terms of root mean square error. Sample patterns were optimized based on the kriging variance and the weighted means of shortest distance criterion using the simulated annealing algorithm. The optimized sample patterns outperformed systematic sample patterns in terms of mean kriging variance mainly for small sample sizes. These findings suggest methods for increasing efficiency of microclimate monitoring in riparian areas

Undernutrition among Ethiopian adults living with HIV: a meta-analysis.

BackgroundMalnutrition and human immunodeficiency virus (HIV) are interlaced in a vicious cycle and worsened in low and middle-income countries. In Ethiopia, even though individuals are dually affected by both malnutrition and HIV, there is no a nationwide study showing the proportion of malnutrition among HIV-positive adults. Consequently, this review addressed the pooled burden of undernutrition among HIV-positive adults in Ethiopia.MethodsWe searched for potentially relevant studies through manual and electronic searches. An electronic search was carried out using the database of PubMed, Google Scholar, and Google for gray literature and reference lists of previous studies. A standardized data extraction checklist was used to extract the data from each original study. STATA Version 13 statistical software was used for our analysis. Descriptive summaries were presented in tables, and the quantitative result was presented in a forest plot. Heterogeneity within the included studies was examined using the Cochrane Q test statistics and I 2 test. Finally, a random-effects meta-analysis model was computed to estimate the pooled proportion of undernutrition among HIV-positive adults.ResultsAfter reviewing 418 studies, 15 studies met the inclusion criteria and were included in the meta-analysis. Findings from 15 studies revealed that the pooled percentage of undernutrition among HIV-positive adults in Ethiopia was 26% (95% CI: 22, 30%). The highest percentage of undernutrition (46.8%) was reported from Jimma University specialized hospital, whereas the lowest proportion of undernutrition (12.3%) was reported from Dilla Hospital. The subgroup analyses of this study also indicated that the percentage of undernourishment among HIV-positive adults is slightly higher in the Northern and Central parts of Ethiopia (27.5%) as compared to the Southern parts of Ethiopia (25%).ConclusionThis study noted that undernutrition among HIV-positive adults in Ethiopia was quite common. This study also revealed that undernutrition is more common among HIV-positive adults with advanced disease stage, anemia, diarrhea, CD4 count less than 200 cells/mm3, and living in rural areas. Based on our findings, we suggested that all HIV-positive adults should be assessed for nutritional status at the time of ART commencement

Teaching in Contemporary Forest Resources Curricula: Applications to Courses in Forest Measurements and Biometrics

Foresters face new and evolving challenges as society reconsiders the balance of its interests between wood production and the provision of ecosystem services in the management of forests. Whatever paths this process may take, sound and broad-based decisions will continue to require accurate and relevant measurements of current forest conditions and projections of future conditions under alternative management programs. Forest measurements and biometrics (FMB) will remain a key component of future forest management and a critical element in the education of future forest managers. As professors who both teach and do research in FMB, we offer teaching goals that we believe will improve FMB education in forestry schools to meet future needs. In the following sections, we outline teaching goals for university-level instruction in forest resources curricula and the roles of FMB in modern forestry. We then identify what we feel are the most critical challenges in teaching and learning FMB and discuss selected strategies to meet teaching objectives for FMB. A fourth section presents an overview of how selected strategies can be integrated into FMB classes, including examples and comments on the role that new technology might play in meeting the above-described challenges. The final section summarizes our main points and provides concluding remarks.This is the author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by the Society of American Foresters and can be found at: http://www.safnet.org/publications/jof/index.cfm.Keywords: forest inventory and monitoring, teaching applied statistics, Pacific Northwest, forest analysis, forest pedagog