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Characterization of Forest Degradation beyond Canopy Cover Change in Mau Forest, Kenya

Open Journal of Forestry 2022年第4期12卷 393-407页

作者： Merceline Awuor Ojwala Felix Mutua mwangi James Kinyanjui Department of Geomatic Engineering and Geospatial Information Systems Jommo Kenyatta University of Agriculture and Technology Nairobi Kenya Directorate of Resource Surveys and Remote Sensing Nairobi Kenya School of Natural Resources and Environmental Studies Karatina University Karatina Kenya

Monitoring Forest degradation is evidence enough to show a country’s commitment to monitor the forest trend both for national and local decision-making and international reporting processes. Unlike deforestation which is easier to point out, monitoring forest degradation is quite a challenge since there is no universal definition and thus no clear monitoring methods apart from the canopy cover change. This research, therefore, sought to look at the degradation trends in the Mau forest complex between 1995-2020 with the aim of finding out whether monitoring canopy density changes over time and quantifying these changes in terms of biomass loss could be a good approach in monitoring forest degradation. Forest Canopy Density (FCD) model was adopted focusing on using vegetation indices describing biophysical conditions of Vegetation, Shadow and Bareness to monitor changes in canopy density as a parameter for describing forest degradation in the forest blocks of Maasai Mau and Olpusimoru in Mau forest complex. Results indicated how different vegetation indices responded to changes in the vegetation density and eventually changes in the canopy density values which were converted in terms of biomass loss. The forest Canopy Density model proved to be a good tool for monitoring forest degradation since it combines different biophysical indices with different characteristics capturing what is happening below the canopy.

关键词： Forest Degradation Canopy Density Vegetation Indices Biomass Loss Monitoring

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Antimicrobial peptide LL-37 forms complex with bacterial DNA to facilitate blood translocation of bacterial DNA and aggravate ulcerative colitis

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Science Bulletin 2018年第20期63卷 1364-1375页

作者： Zilei Duan Yaqun Fang Yang Sun Ning Luan Xue Chen Mengrou Chen Yajun Han Yizhu Yin James mwangi Junkun Niu Kunhua Wang Yinglei Miao Zhiye Zhang Ren Lai Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province Kunming Institute .of ZoologyKunming 650223China Life Sciences College of Nanjing Agricultural University Nanjing 210095China Department of Gastroenterology The First Affiliated Hospital of Kunming Medical UniversityKunming 650032China Department of General Surgery The First Affiliated Hospital of Kunming Medical UniversityKunming 650032China Kunming College of Life Science University of Chinese Academy of SciencesKunming 650204China Sino-African Joint Research Center Kunming Institute of ZoologyChinese Academy of SciencesKunming 650223China

Bacterial DNA(bacDNA) is frequently found in serum of patient with ulcerative colitis(UC) and Crohn's disease, even blood bacterial culture is negative. How bacDNA evades immune elimination and is translocated into blood remain unclear. Here, we showed that bacDNA avoids elimination and disables bacteriakilling function of antimicrobial peptide LL-37(Cramp in mice) by forming complex with LL-37, which is inducible after culture with bacteria or bacterial products. Elevated LL-37-bacDNA complex was found in plasma and lesions of patients with UC. LL-37-bacDNA promoted inflammation by inducing Th1, Th2 and Th17 differentiation and activating toll-like receptor-9(TLR9). The complex also increased paracellular permeability, which possibly combines its inflammatory effects to promote local damage and bacDNA translocation into blood. Cramp-bacDNA aggravated mouse colitis severity while interference with the complex ameliorated the disease. The study identifies that inflammatogenic bacDNA utilizes LL-37 as a vehicle for blood translocation and to evade immune elimination. Additionally, bacteria may make a milieu by releasing bacDNA to utilize and resist host antimicrobial peptides as a ‘trojan horse'.

关键词： Ulcerative colitis Bacterial DNA LL-37 Immune elimination Chronic inflammation

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东非肯尼亚茜草科植物多样性及空间格局

东非肯尼亚茜草科植物多样性及空间格局

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作者： mwangi Njoroge Brian 中国科学院大学(中国科学院武汉植物园)

学位级别：硕士

茜草科是世界被子植物第四大科,约占所有全球开花植物的4%,广布于热带和亚热带地区,少数草本延伸至寒带。撒哈拉以南非洲,包括热带东非地区,特别是肯尼亚和坦桑尼亚的山区和沿海森林,具有大量的茜草科植物,特别是稀有和特有物种。近年来... 详细信息

茜草科是世界被子植物第四大科,约占所有全球开花植物的4%,广布于热带和亚热带地区,少数草本延伸至寒带。撒哈拉以南非洲,包括热带东非地区,特别是肯尼亚和坦桑尼亚的山区和沿海森林,具有大量的茜草科植物,特别是稀有和特有物种。近年来,一些茜草科的新类群在肯尼亚不断被发现,同时一些新记录也陆续被报道,表明该地区茜草科多样性研究还不够充分。本研究的目的是通过标本查阅和野外考察,查明肯尼亚茜草科植物的多样性,并记录其在肯尼亚47个县的详细分布,同时,依据最新的分子系统对该科植物进行修订,为编撰《肯尼亚植物志》提供本底资料。本研究对来自东非植物标本馆（EA）、英国皇家植物园植物标本馆（Kew）和中国科学院武汉植物园植物标本馆（HIB）的肯尼亚茜草科2万多份标本进行了核查和数字化,并根据最新的分类系统对所有物种进行了修订,得到肯尼亚茜草科植物的物种名录。通过所有标本的详细经纬度信息,计算各物种的空间分布以及县级的物种丰富度和特有丰富度。研究结果表明,肯尼亚茜草科植物共274种,隶属于3亚科32个族81属。在47个县级的物种丰富度分析种显示,物种丰富度最高的属是九节属（Psychotria）、大沙叶属（Pavetta）和水线草属（Oldenlandia）。物种丰富度最高的县分别是夸勒（Kwale）、基里菲（Kilifi）和泰塔塔维塔县（Taita Taveta）。肯尼亚茜草科特有种共有36种,其中仍有13种未确定,需要进一步进行野外调查。研究发现,肯尼亚的许多地区,特别是北部和东北部的县,仍然只有很少的标本收集。沿海地区的县物种丰富度最高。基于当前IUCN的濒危等级评估,肯尼亚茜草科约有2种濒临灭绝,5种易危,因此需要加大对这些物种栖息地的保护力度。本研究基于大量的标本资料,并结合当前最新的分子系统,全面研究了茜草科植物在肯尼亚的种类（包括亚科、族、属等）、特有性、以及该科植物在肯尼亚的县级分布,为《肯尼亚植物志》-茜草科卷册的编撰以及该科植物野外调查和保护提供了基础信息。

关键词：肯尼亚县茜草科物种丰富度特有性

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Mixture Ratio Estimators Using Multi-Auxiliary Variables and Attributes for Two-Phase Sampling

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Open Journal of Statistics 2014年第9期4卷 776-788页

作者： Paul mwangi Waweru John Kung’u James Kahiri Department of Statistics and Actuarial Science Kenyatta University Nairobi Kenya

In this paper, we have proposed three classes of mixture ratio estimators for estimating population mean by using information on auxiliary variables and attributes simultaneously in two-phase sampling under full, partial and no information cases and analyzed the properties of the estimators. A simulated study was carried out to compare the performance of the proposed estimators with the existing estimators of finite population mean. It has been found that the mixture ratio estimator in full information case using multiple auxiliary variables and attributes is more efficient than mean per unit, ratio estimator using one auxiliary variable and one attribute, ratio estimator using multiple auxiliary variable and multiple auxiliary attributes and mixture ratio estimators in both partial and no information case in two-phase sampling. A mixture ratio estimator in partial information case is more efficient than mixture ratio estimators in no information case.

关键词： Ratio Estimator Multiple Auxiliary Variables Multiple Auxiliary Attributes Two-Phase Sampling Bi-Serial Correlation Coefficient

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Fetal Urinary Obstruction and Intervention for Sacrococcygeal Teratoma:A Case Report From Kenya

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Maternal-Fetal Medicine 2024年第3期6卷 196-200页

作者： Maryanne Muthoni mwangi Sikolia Wanyonyi Stanley Mugambi Department of Obstetrics and Gynaecology Aga Khan UniversityNairobi 30270-00100Kenya Department of pediatric Surgery Aga Khan UniversityNairobi 30270-00100Kenya

Fetal lower urinary tract obstruction is a rare condition commonly associatedwith significant perinatalmorbidity andmortality,particularly when detected in the second *** concurrent presentation of a recto-urethral fistula with membranous urethral atresia and sacrococcygeal teratoma has not been *** describe a case of extrinsic fetal lower urinary tract obstruction related to a recto-urethral fistula,diagnosed at 33 weeks gestation and managed by serial vesicocentesis until 38 *** case,notable for its absence of hypoplasia despite late diagnosis,resulted in a term delivery of a male *** delivery,pediatric surgeons performed an abdominal perineal resection of the *** vesicocentesis remains a viable management option for patients without access to intrauterine surgical interventions.

关键词： Lower urinary tract symptom Fetal lower urinary tract obstruction Vesicocentesis Sacrococcygeal teratoma Rectourinary fistula

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Effects of Sawdust, Forest Soil and Cow Dung Mixtures on Growth Characteristics of Blue Gum (<i>Eucalyptus saligna</i>) Seedlings in South Kinangop Forest, Nyandarua, Kenya

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Open Journal of Forestry 2017年第4期7卷 373-387页

作者： Fredrick Atanas Ashiono Hellen Kamiri Wangechi mwangi James Kinyanjui Kenya Forest Service South Kinangop Forest Station Nairobi Kenya School of Natural Resources and Environmental Studies Department of Natural Resources Karatina University Karatina Kenya School of Agriculture and Biotechnology Department of Crop Science Karatina University Karatina Kenya

Forestation programs, in Kenya have been hindered by, among others, high cost of tree seedling production and longtime seedlings stay in the nursery. This has been attributed to poor quality of forest soil and unavailability of alternative growth media. Study was carried out in South Kinangop forest station to evaluate the potential of mixing sawdust and cow dung with forest soil to form a nutrient rich growth media. Using forest soil;sawdust, cow dung and mixture of these components, this study sought to determine growth characteristics of Eucalyptus saligna seedlings under different conditions available in the nursery. The experiment was laid out in a Completely Randomized Design (CRD) with six treatments comprising of Saw dust alone (Tr 1), Forest soil alone (Tr 2);Sawdust: Cow dung mixture in the ratio of 1:1 (Tr 3);Forest soil to Sawdust-Cow dung mixture (1:1) in ratio of 1:1 by weight (Tr 4);Forest soil to Sawdust-Cow dung mixture (1:1) in ratio of 1:2 by weight (Tr 5) and Forest soil to Sawdust-Cow dung (1:1) in ratio of 1:3 by weight (Tr 6). Treatments were replicated three times and an experimental unit consisted of 110 seedlings of which 15 were tagged for height and root collar diameter measurement. The remaining 95 were used for biomass determination by destructive sampling. The results showed that Sawdust: Cow dung mixtures (Tr 3) had the highest measurements for height, root collar diameter and biomass at week 20 when compared to the rest of growth mixtures. Height measurements were significantly high (13.81 cm) for the Sawdust: Cow dung mixtures while the variation in root collar diameter and biomass were not significantly different among the treatments. Sawdust alone did not favor seedling growth and recorded the lowest measurements in height, root collar diameter and biomass. Nutrient release from the growth media during the experimental period was equally high for the Saw dust: Cow dung mixture (Tr 3) which was ideal media for raising tree seedling

关键词： CowDung Forest Soil Sawdust Tree Seedling

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Natural regeneration and ecological recovery in Mau Forest complex, Kenya

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Open Journal of Ecology 2013年第6期3卷 417-422页

作者： James mwangi Kinjanjui Moses Karachi Kennedy Nyambuti Ondimu Department of Geography Egerton University Egerton Kenya Department of Natural Resources Egerton University Egerton Kenya Department of Resource Survey and Remote Sensing Nairobi Kenya

This study investigated natural ecological recovery in parts of Western and Southwestern blocks of theMauForestcomplex that had experienced varied levels of disturbance. The extent and speed of regeneration in the disturbed regions since the eviction of the setter population were not known. This study thus now provides current baseline data on plant distribution, germination of soil bank seeds, and soil nutrient content. The number of tree species recorded at different levels of disturbance were in increas- ing order: moderately disturbed (MDF) > undisturbed (UDF) > heavy disturbed forest (HDF). Forest clearing reduced forest basal area and forest stocking of big trees (dbh ≥40 cm) in the HDF by more than 4 and 6 times, respectively, than those in UDF. Tree importance values indicated a reduction in commercially valuable species in HDF. Early colonizers and fire tolerant species were predominant in the HDF whereas non-commercial species dominated MDF. Viable soil seed reserves decreased with soil depth in all forests but content between 0 -20 cmsoil depth showed a potential to support regeneration. Total N, organic C and available P decreased with increase in forest disturbance. Overall, the disturbed sites showed a general potential for ecological recovery and natural regeneration to UDF status.

关键词： Disturbance Regeneration Soil Seed Bank Germination Nutrients

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Variation in Levels of Flavonols Myricetin, Quercetin and Kaempferol—In Kenyan Tea (<i>Camellia sinensis L.</i>) with Processed Tea Types and Geographic Location

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Open Journal of Applied Sciences 2021年第6期11卷 736-749页

作者： Simon mwangi Kingori Simon Oduor Ochanda Robert Kipyegon Koech Kenya Agricultural and Livestock Research Organization Tea Research Institute (KALRO) Kericho Kenya

The aim of this study was to determine the levels of myricetin, quercetin, and kaempferol in green and black Kenyan types in relation to geographic location of production. Tea samples were extracted before chromatographic separations with a Shimadzu 20A HPLC coupled with PDA. Flavonol levels were quercetin > kaempferol > myricetin. Teas from east of rift, had quercetin 1.25-1.83 mg/g and 1.29-1.71 mg/g for green and black types, respectively. Kaempferol levels were between 1.28-1.72 mg/g in green and 1.36-1.76 mg/g in black tea. Myricetin ranged at 0.40-0.79 mg/g green and 0.12-0.38 mg/g black tea types. Total flavonols in green tea were highest at 4.28 mg/g while black tea was 3.83 mg/g. These trends agree well with those observed in teas west of the rift. For tea types, myricetin and kaempferol showed a significant difference (P

关键词： Samples Extracted Chromatographic Separations

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Modeling impacts of climate change on the potential distribution of six endemic baobab species in Madagascar

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Plant Diversity 2021年第2期43卷 117-124页

作者： Jun-Nan Wan Ndungu J.Mbari Sheng-Wei Wang Bing Liu Brian N.mwangi Jean R.E.Rasoarahona Hai-Ping Xin Ya-Dong Zhou Qing-Feng Wang Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture Wuhan Botanical GardenChinese Academy of SciencesWuhanHubei430074PR China State Key Laboratory of Systematic and Evolutionary Botany Institute of BotanyChinese Academy of SciencesBeijing100093PR China University of Chinese Academy of Sciences Beijing100049PR China Sino-Africa Joint Research Center Chinese Academy of SciencesWuhanHubei430074PR China High School of Agricultural Sciences University of AntananarivoP.O.Box 175Madagascar

Madagascar,a globally renowned biodiversity hotspot characterized by high rates of endemism,is one of the few remaining refugia for many plants and animal ***,global climate change has greatly affected the natural ecosystem and endemic species living in Madagascar,and will likely continue to influence species distribution in the *** is home to six endemic baobab(Adansonia spp.,Bombacoideae[Malvaceae])species(Adansonia grandidieri,***,***,***,***,***),which are remarkable and endangered *** study aimed to model the current distribution of suitable habitat for each baobab species endemic to Madagascar and determine the effect that climate change will have on suitable baobab habitat by the years 2050 and *** distribution was modeled using MaxEnt based on locality information of 245 occurrence sites of six species from both online database and our own field work.A total of seven climatic variables were used for the modeling *** present distribution of all six Madagascar's baobabs was largely influenced by temperature-related *** both expansion and contraction of suitable habitat are predicted for all species,loss of original suitable habitat is predicted to be *** the most widespread Madagascar baobab,***,more than 40%of its original habitat is predicted to be lost because of climate *** on these findings,we recommend that areas predicted to contract in response to climate change should be designated key protection regions for baobab conservation.

关键词： Madagascar Adansonia Climate change MaxEnt Potential distribution

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Enhancing Pneumonia Detection in Pediatric Chest X-Rays Using CGAN-Augmented Datasets and Lightweight Deep Transfer Learning Models

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Journal of Data Analysis and Information Processing 2024年第1期12卷 1-23页

作者： Coulibaly Mohamed Ronald Waweru mwangi John M. Kihoro Department of Mathematics Pan African University Institute for Basic Sciences Technology and Innovation (PAUSTI) Nairobi Kenya Department of Computing Jomo Kenyatta University of Agriculture and Technology Nairobi Kenya School of Computing and Mathematics The Cooperative University of Kenya Nairobi Kenya

Pneumonia ranks as a leading cause of mortality, particularly in children aged five and under. Detecting this disease typically requires radiologists to examine chest X-rays and report their findings to physicians, a task susceptible to human error. The application of Deep Transfer Learning (DTL) for the identification of pneumonia through chest X-rays is hindered by a shortage of available images, which has led to less than optimal DTL performance and issues with overfitting. Overfitting is characterized by a model’s learning that is too closely fitted to the training data, reducing its effectiveness on unseen data. The problem of overfitting is especially prevalent in medical image processing due to the high costs and extensive time required for image annotation, as well as the challenge of collecting substantial datasets that also respect patient privacy concerning infectious diseases such as pneumonia. To mitigate these challenges, this paper introduces the use of conditional generative adversarial networks (CGAN) to enrich the pneumonia dataset with 2690 synthesized X-ray images of the minority class, aiming to even out the dataset distribution for improved diagnostic performance. Subsequently, we applied four modified lightweight deep transfer learning models such as Xception, MobileNetV2, MobileNet, and EfficientNetB0. These models have been fine-tuned and evaluated, demonstrating remarkable detection accuracies of 99.26%, 98.23%, 97.06%, and 94.55%, respectively, across fifty epochs. The experimental results validate that the models we have proposed achieve high detection accuracy rates, with the best model reaching up to 99.26% effectiveness, outperforming other models in the diagnosis of pneumonia from X-ray images.

关键词： Pneumonia Detection Pediatric Radiology CGAN (Conditional Generative Adversarial Networks) Deep Transfer Learning Medical Image Analysis

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