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The Impacts and Causes of Land Fragmentation on Farm Productivity: Case Review of East African Countries

Open Journal of Ecology 2024年第5期14卷 455-482页

作者： Joseph Mayindo Mayele jacob b. kolleh Joel Emmanuel Sab.ri Department of Agricultural and Resource Economics The University of Tokyo Tokyo Japan Department of Forestry and Wildlife College of Natural Resources and Environmental Studies University of Juba Juba South Sudan Department of Socio-Economic and Applied Statistics Central Agricultural Research Institute (CARI) Suakoko Liberia

This report provides an overall assessment of land fragmentation prob.ems in East Africa. Many parts of East Africa have b.come highly fragmented, putting development systems and activities in these areas at risk of complete collapse. Land fragmentation occurs when land gets converted for agriculture, industrialization, or urb.nization, invaded b. non-local plants, or enclosed for individual use and b. sub.ividing farmlands into sub.equent smaller units called parcels with varying average farm sizes. Fragmentation results from inappropriate agricultural development processes and ineffective land use planning that fails to recognize how farmland is used, and the importance of its interconnected areas. Insecurity of tenure and resource rights are key factors in making this possib.e. Land fragmentation is one of the key reasons why the ab.lity of most resources in East Africa b.comes scarcer, and those remaining b.come “privatized” b. more powerful community memb.rs—keen to maintain their access to them. Such individualistic attitudes are new and disadvantage the poorest even further b. affecting the traditional customary safety nets and agricultural outputs. Neither the government nor customary governance systems effectively protect resource access for the poorest. This review summary report identifies the key causes, measures, and implications, government interventions, and the common remedies to land fragmentation prob.ems in the East African Countries of Kenya, Uganda, Rwanda, and Tanzania including neighb.ring Ethiopia, and the Sudan. The findings indicated from 2005 to 2015, the population kept increasing for all the named countries in East Africa with Rwanda and Uganda having a sub.tantial increase in population density. The study review further explores the trend in the performance of agriculture b. average farm sizes within the intervals of five years b. highlighting their strong linkages and found that the average farm size has declined drastically, especiall

关键词： Land Fragmentation Land Consolidation Farm Productivity Industrialization Impacts Causes Average Farm Size Population East Africa

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Resonant Raman scattering in GaN single crystals and GaN-b.sed heterostructures: feasib.lity for laser cooling

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Chinese Optics Letters 2013年第1期11卷 63-71页

作者： Yujie J. Ding jacob b. Khurgin Department of Electrical and Computer Engineering Lehigh University Department of Electrical and Computer Engineering The Johns Hopkins University

The recent progress on Raman scattering in GaN single crystals and GaN/A1N heterostructures is re- viewed. Anti-Stokes Raman scattering is used to determine electron-phonon scattering time and decay time constant for longitudinal-opticat phonons. In a typical high electron mob.lity transistor b.sed on GaN/A1N heterostructures, strong resonances are reached for the first-order and second-order Raman scattering processes. Therefore, b.th Stokes and anti-Stokes Raman intensities are dramatically enhanced. The feasib.lity for laser cooling of a nitride structure is studied. A further optimization will enab.e us to reach the threshold for laser cooling. Raman scattering have potential applications in up-conversion lasers and laser cooling of nitride ultrafast electronic and optoelectronic devices.

关键词： GaN Ra Resonant Raman scattering in GaN single crystals and GaN-b.sed heterostructures feasib.lity for laser cooling

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Effects of rodent ab.ndance and richness on cache pilfering

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Integrative Zoology 2018年第3期13卷 331-338页

作者： jacob W.DITTEL Stephen b.VANDER WALL Department of Fisheries and Wildlife Oregon State UniversityCorvallisOregonUSA Department of b.ology and the Program in Ecology Evolutionand Conservation BiologyUniversity of NevadaRenoNevadaUSA

Scatterhoarding is a common b.havioral strategy to conserve food during periods of scarcity,b.t this type of food storage is vulnerab.e to theft or pilferage.A variety of environmental factors and cache characteristics influence the rate of *** we investigate 2 environmental factors,which heretofore have not received much attention:the ab.ndance and species richness of scatterhoarding animals in the vicinity of scatterhoarded *** measured the rate of cache pilferage at 7 sites that differed in the numb.r and species composition of granivorous rodents in western Nevada using local native seeds and sunflower *** found that there was no difference b.tween the pilferage rate of native seeds and sunflower seeds,b.t that sites with different rodent ab.ndances had different pilferage *** rates were proportional to the ab.ndance of scatterhoarding *** rodents removed seeds at the rate of 1.3%/day/rodent *** richness of scatterhoarding rodents was not correlated with rates of *** results suggest that density-dependent competition for scatterhoarded seeds is a strong determinant of pilferage rates.

关键词： cache pilfering competition food hoarding heteromyids rodent ab.ndance scatter hoarding sciurids

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Factors controlling nutrient availab.lity to the developing fetus in ruminants

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Journal of Animal Science and b.otechnology 2015年第2期6卷 205-214页

作者： Kathrin A Dunlap jacob D b.own Ashley b.Keith M Carey Satterfield Department of Animal Science Texas A&M University2471 TAMU College Station

Inadequate delivery of nutrients results in intrauterine growth restriction （IUGR）, which is a leading cause of neonatal morb.dity and mortality in livestock. In ruminants, inadequate nutrition during pregnancy is often prevalent due to frequent utilization of exensive forage b.sed grazing systems, making them highly susceptib.e to changes in nutrient quality and availab.lity. Delivery of nutrients to the fetus is dependent on a numb.r of critical factors including placental growth and development, utero-placental b.ood flow, nutrient availab.lity, and placenta metab.lism and transport capacity. Previous findings from our lab.ratory and others, highlight essential roles for amino acids and their metab.lites in supporting normal fetal growth and development, as well as the critical role for amino acid transporters in nutrient delivery to the fetus. The focus of this review will b. on the role of materna nutrition on placental form and function as a regulator of fetal development in ruminants.

关键词： Intrauterine growth restriction Nutrient transport Placenta Ruminant

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The Mathematical Theory of Multifocal Lenses(Dedicated to Professor Haim b.ezis on the occasion of his 70th b.rthday)

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Chinese Annals of Mathematics,Series b 2017年第2期38卷 647-660页

作者： jacob RUb.NSTEIN department of mathematics TechnionHaifa 32000Israel

This paper presents the fundamental optical concepts of designing multifocal ophthalmic lenses and the mathematical methods associated with them. In particular, it is shown that the design methodology is heavily b.sed on differential geometric ideas such as Willmore surfaces. A key role is played b. Hamilton's eikonal functions. It is shown that these functions capture all the information on the local b.ur and distortion created b. the lenses. Along the way, formulas for computing the eikonal functions are derived. Finally,the author lists a few intriguing mathematical prob.ems and novel concepts in optics as future projects.

关键词： Optical design, Differential geometry, Eikonal functions,Multifocal lenses

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Integrative b.havioral ecotoxicology： b.inging together fields to estab.ish new insight to b.havioral ecology, toxicology, and conservation

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Current Zoology 2017年第2期63卷 185-194页

作者： Elizab.th K. PETERSON David b. b.CHWALTER jacob L. KERb. Matthew K. LEFAUVE Claire W. VARIAN-RAMOS John R SWADDLE Department of b.ological Sciences State University of New York-Albany Albany NY 12222 USA Department of b.ological Sciences North Carolina State University Raleigh NC 27695 USA Department of b.ology University of South Dakota Vermillion SD 57069 USA Department of b.ological Sciences George Washington University Washington DC 20052 USA Department of b.ology Colorado State University-Pueblo Pueblo CO 81001 USA b.ology Department Institute for Integrative Bird Behavior Studies College of William & Mary Williamsburg VA 23187-8795 USA

The fields of b.havioral ecology, conservation science, and environmental toxicology individually aim to protect and manage the conservation of wildlife in response to anthropogenic stressors, including widespread anthropogenic pollution. Although great emphasis in the field of toxicology has b.en placed on understanding how single pollutants affect survival, a comprehensive, interdis- ciplinary approach that includes b.havioral ecology is essential to address how anthropogenic compounds are a risk for the survival of species and populations in an increasingly polluted world. We provide an integrative framework for b.havioral ecotoxicology using Tinb.rgen＇s four postu- lates （causation and mechanism, development and ontogeny, function and fitness, and evolution- ary history and phylogenetic patterns）. The aims of this review are： 1） to promote an integrative view and re-define the field of integrative b.havioral ecotoxicology; 2） to demonstrate how study- ing ecotoxicology can promote b.havior research; and 3） to identify areas of b.havioral ecotoxicol- ogy that require further attention to promote the integration and growth of the field.

关键词： animal b.havior b.havioral ecology conservation phylogenetic pollution toxicology.

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Properties of the Secondary Hochschild Homology

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Algeb.a Colloquium 2018年第2期25卷 225-242页

作者： jacob Laub.cher Department of Mathematics St. Norbert College De Pere Wisconsin 54115 USA

In this paper we study properties of the secondary Hochschild homology of the triple （A, b. ε） with coefficients in M. We estab.ish a type of Morita equivalence b.tween two triples and show that H.（（A,b.ε）; M） is invariant under this equivalence. We also prove the existence of an exact sequence which connects the usual and the secondary Hochschild homologies in low dimension~ allowing one to perform easy computations. The functoriality of H.（（A, b. ε）; M） is also discussed.

关键词： Hochschild homology Morita equivalence

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Physiological Responses of <i>Tamarix ramosissima</i>to Extreme NaCl Concentrations

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American Journal of Plant Sciences 2011年第6期2卷 808-815页

作者： jacob M. Carter Jesse b. Nippert Division of b.ology Kansas State University Department of Ecology and Evolutionary b.ology University of Kansas Division of b.ology Kansas State University

Hydrologic alterations of river systems in western North America over the past century have increased soil salinity, contrib.ting to the estab.ishment and spread of an introduced halophytic species, Tamarix ramosissima (Ledeb.). The physiological responses of Tamarix ramosissima to salinity stress are incompletely known. To assess the salinity tolerance of this species, we measured several whole plant and leaf-level physiological responses of Tamarix ramosissima cuttings grown in a controlled environment over three NaCl concentrations (0, 15 and 40 g l-1). Tamarix ramosissima photosynthesis (A2000), stomatal conductance to water (gs), water potential (Ψw), and the maximum quantum yield of photosystem II (Fv/Fm) decreased at 15 and 40 g l-1 NaCl compared to control treatments. However, after approximately 35 days, Tamarix ramosissima had increased photosynthetic rates, maximum quantum yield of photosystem II, and stomatal conductance to water. These data suggests that physiological functioning of Tamarix ramosissima acclimated to extremely high NaCl concentrations over a relatively short period of time. Additionally, we present preliminary evidence that suggests proline synthesis may b. the mechanism b. which this species adjusts osmotically to increasing salinity.

关键词： Chlorophyll Fluorescence Gas Exchange Proline Saltcedar Salt stress Tamarisk

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Taenia solium taeniasis and cysticercosis:extinction or outb.eak

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Animal Diseases 2023年第2期3卷 90-103页

作者： jacob I.Irunde Faraja b.Luhanda Department of Mathematics Physics and InformaticsMkwawa University College of EducationIringaTanzania Department of Applied Mathematics and Computational Sciences The Nelson Mandela African Institution of Science and TechnologyArushaTanzania

Taenia solium taeniasis and cysticercosis are neglected zoonotic diseases that affect human health and economies of developing *** this work,we formulate and analyze deterministic and continuous time Markov chain(CTMC)stochastic models to determine parameters that drive Taenia solium taeniasis and cysticercosis and the likelihood of their *** b.sic reproduction numb.r R0 is computed b. the next generation matrix approach,sensitivity index of each parameter in R0 is derived b. the normalized forward sensitivity index and the likelihood of diseases’extinction is computed b. the multitype b.anching *** analysis shows that humans with Taenia solium taeniasis,infectious pork and Taenia solium eggs in the environment play an important role in the transmission of Taenia solium taeniasis and cysticercosis,and the model exhib.ts forward b.furcation at R0=*** implies that R0b.b.lity of Taenia solium taeniasis and cysticercosis extinction is high if the diseases emerge from humans with Taenia solium cysticercosis and there is an outb.eak if the diseases emerge from either humans with Taenia solium taeniasis or infectious pork or Taenia solium eggs in the *** control Taenia solium taeniasis and cysticercosis,the intervention strategies should focus on improving hygiene and sanitation for reducing shedding rate of Taenia solium eggs in the environment,inspection of pork for reducing the rate of acquiring Taenia solium taeniasis and spraying of insecticides for killing Taenia solium eggs in the environment.

关键词： Taeniasis Cysticercosis b.sic reproduction numb.r Sensitivity analysis Multitype b.anching process Stochastic model

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Mechanisms and treatment strategies of demyelinating and dysmyelinating Charcot-Marie-Tooth disease

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Neural Regeneration Research 2023年第9期18卷 1931-1939页

作者： Nadège Hertzog Claire jacob Faculty of b.ology Institute of Developmental Biology and NeurobiologyJohannes Gutenberg University MainzHanns-Dieter-Hüsch-WegMainzGermany

Schwann cells,the myelinating glia of the peripheral nervous system,wrap axons multiple times to b.ild their myelin *** is of paramount importance for axonal integrity and fast axon potential ***,myelin is lacking or dysfunctional in several neuropathies including demyelinating and dysmyelinating Charcot-M arie-To oth ***-Marie-To oth disease represents the most prevalent inherited neuropathy in humans and is classified either as axonal,demyelinating or dysmyelinating,or as *** demyelinating or dysmyelinating forms of Charcot-Marie-Tooth disease constitute the majority of the disease cases and are most frequently due to mutations in the three following myelin genes:peripheral myelin protein 22,myelin protein ze ro and gap junction b.ta 1(coding for Connexin 32) causing Charcot-M arie-Tooth disease type 1A,Charcot-Marie-Tooth disease type 1b.and X-linked Charcot-M arie-Tooth disease type 1,*** resulting perturb.tion of myelin structure and function leads to axonal demyelination or dysmyelination and causes severe disab.lities in affected *** treatment to cure or slow down the disease progression is currently availab.e on the market,howeve r,scientific discoveries led to a b.tter understanding of the pathomechanisms of the disease and to potential treatment *** this review,we describ. the features and molecular mechanisms of the three main demyelinating or dysmyelinating forms of Charcot-Marie-Tooth disease,the rodent models used in research,and the emerging therapeutic approaches to cure or counteract the progression of the disease.

关键词： Charcot-Marie-Tooth disease rodent models emerging treatments demyelination and dysmyelination endoplasmic reticulum stress gene therapy myelin repair Schwann cells unfolded protein response

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