检索结果-南通市图书馆

Correlating rodent community structure with ecological integrity, Tussen-die-Riviere Nature Reserve, Free State province, South Africa

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Integrative Zoology 2007年第4期2卷 212-219页

作者： nico l.avenant Paolo CAVAllINI Department of Mammalogy National Museumand Centre for Environmental ManagementUniversity of the Free StateBloemfonteinSouth Africa Faunalia Consulenze Pontedera PI 56025Italy

Rodents form a vital component of Free State ecosystems and monitoring them may be a relatively quick andinexpensive method of indicating healthy or unhealthy ecosystem functioning. Using removal trapping, we havestudied rodent seasonal abundance, species richness, Shannon diversity, and evenness of rodents in four habitats inthe Tussen-die-Riviere Nature Reserve, inspected the most successful sampling method for these habitats, andreport on their community structure and how it is related to an Ecological Index (≈ EI value of grassland). Bothspecies richness and Shannon diversity increased significantly with EI value. The indicator species Mastomyscoucha occurred at all plots, but contributed the largest proportion of the total captures (ca. 80%) at the plot withlowest EI value. Other results important for small mammal monitoring and collecting are that trap success andspecies richness was highest in autumn. This study also confirms that four days and nights continuous trapping isessential for the effective sampling of rodent communities in Free State grasslands. Our results partially supportexpectations that the number of specialist species increases with succession, M. coucha dominance acts as anindicator of habitat disturbance, rodent species richness conforms to Tilman’s hump-shaped curve model, and addsto a baseline of diversity indices in a variety of grassland habitats.

关键词： community structure diversity ecological integrity rodents species richness

Integrating small mammal community variables into aircraft–wildlife collision management plans at Namibian airports

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Integrative Zoology 2015年第6期10卷 515-530页

作者： Morgan l.HAUPTFlEISCH nico l.avenant Department of Agriculture and Natural Resources Sciences Polytechnic of NamibiaWindhoekNamibia Department of Mammalogy National Museumand Centre for Environmental ManagementUniversity of the Free StateBloemfonteinSouth Africa

Understanding ecosystems within and around airports can help to determine the causes and possible mitigation measures for collisions between aircraft and *** mammal communities are an important component of the semi-arid savanna ecosystems of Namibia,its productivity and its ecosystem *** are also a major direct attractant for raptors at *** present study compared the abundance and diversity of small mammals between Namibia’s 2 main airport properties(Hosea Kutako International Airport and Eros Airport),and among areas of land used for various purposes surrounding the airports.A total of 2150 small mammals(3 orders,11 species)were captured over 4 trapping *** mammal abundance was significantly higher at the end of the growing season than during the non-growing *** grass mowing regimen in current management plans at the airports resulted in a significant reduction of small mammal abundance at Hosea Kutako during the non-growing season only,thus indicating that annual mowing is effective but insufficient to reduce the overall abundance of mammal prey species for *** mammal numbers were significantly higher at Hosea Kutako Airport compared to the cattle and game farming land surrounding the airport,while no differences in small mammal densities or diversity were found for areas with different land uses at and surrounding *** study suggests that the fence around Hosea Kutako provides a refuge for small mammals,resulting in higher *** also indicates that different surrounding land use practices result in altered ecosystem function and productivity,an important consideration when identifying wildlife attractants at airports.

关键词： airport ecosystems bird strike risk Namibia small mammal indicators

Dental microwear of sympatric rodent species sampled across habitats in southern Africa: Implications for environmental influence

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Integrative Zoology 2016年第2期11卷 111-127页

作者： Jenny H.E.BURGMAN Jennifer lEICHlITER nico l.avenant Peter S.UNGAR Environmental Dynamics Program University of ArkansasFayettevilleArkansasUSA Department of Anthropology University of Colorado BoulderBoulderColoradoUSA National Museum and University of the Free State BloemfonteinSouth Africa Department of Anthropology University of ArkansasFayettevilleArkansasUSA

Dental microwear textures have proven to be a valuable tool for reconstructing the diets of a wide assortment of fossil ***,some studies have recently questioned the efficacy of this approach,suggesting that aspects of habitat unrelated to food preference,especially environmental grit load,might have a confounding effect on microwear patterning that obscures the diet *** we evaluate this hypothesis by examining microwear textures of 3 extant sympatric rodent species that vary in diet breadth and are found in a variety of habitat types:Mastomys coucha,Micaelamys namaquensis and Rhabdomys *** sample each of these species from 3 distinct environmental settings in southern Africa that differ in rainfall and vegetative cover:Nama-Karoo shrublands(semi-desert)and Dry Highveld grasslands in the Free State Province of South Africa,and Afromontane(wet)grasslands in the highlands of *** differences between habitat types are evident for some of the species,inconsistency in the pattern suggests that the microwear signal is driven by variation in foods eaten rather than grit-level per *** is clear that,at least for species and habitats sampled in the current study,environmental grit load does not swamp diet-related microwear signatures.

关键词： diet grit tooth wear

Carnivore stable carbon isotope niches reflect predator–prey size relationships in African savannas

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Integrative Zoology 2018年第2期13卷 166-179页

作者： Jacqueline CODRON nico l.avenant Corli WIGlEY-COETSEE Daryl CODRON Mammalogy Department National MuseumBloemfonteinSouth Africa Florisbad Quaternary Research Department National MuseumBloemfonteinSouth Africa Centre for Environmental Management University of the Free StateBloemfonteinSouth Africa Scientific Services SANParksSkukuzaSouth Africa School of Natural Resource Management Nelson Mandela UniversityGeorge CampusSouth Africa Institute for Geosciences Palaeontology/Sclerochronology Research GroupJohannes Gütenberg UniversityMainzGermany

Predator-prey size relationships are among the most important patterns underlying the structure and function of ecological ***,these relationships have already been shown to be important for understanding patterns of macroevolution and differential extinction in the terrestrial vertebrate fossil *** isotope analysis(SIA)is a powerful remote approach to examining animal diets and *** approach is based on the principle that isotope compositions of consumer tissues reflect those of their *** systems where resource isotope compositions are distributed along a body size gradient,SIA could be used to reconstruct predator-prey size *** analyzed stable carbon isotope distributions amongst mammalian herbivores in extant and Plio-Pleistocene African savanna assemblages,and show that the range ofδ^(13)C values among mammalian prey species(herbivores and rodents)increases with body mass(BM),because C_(4) plant feeding(essentially grazing)is more common among larger ***,δ^(13)C values of mammalian carnivores in these systems are related to species’BM,reflecting a higher average C_(4) prey component in the diets of larger-bodied *** pattern likely emerges because only the largest carnivores in these systems have regular access to the C_(4) prey base,whereas smaller carnivores do ***δ^(13)C-BM relationship observed in mammalian carnivores is a potentially powerful approach for reconstructing and parameterizing predator-prey size relationships in contemporary and fossil savanna assemblages,and for interpreting how various behavioral,ecological and environmental factors influence prey size selection.

关键词： body mass carbonate collagen hair pleistocene

Stable isotope evidence for trophic niche partitioning in a South African savanna rodent community

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Current Zoology 2015年第3期61卷 397-411页

作者： Jacqueline CODRON Kevin J DUFFY nico l.avenant Matt SPONHEIMER Jennifer lEICHlITER Oliver PAINE Paul SANDBERG Daryl CODRON Institute of Systems Science Durban University of Technology Durban South Africa Karoo Palaeontology Deparlnaent National Museum PO Box 266 Bloemfontein 9301 RSA School of Mathematics Statistics and Computer Science University of KwaZulu-Natal Private Bag X01 Scottsville 3209 RSA Denartment of Mammalogv. National Museum. PO Box 266. Bloemfontein 9301. RSA Department of Anthropology University of Colorado at Boulder Boulder CO80309 USA Florisbad Quaternary Research Department National Museum PO Box 266 Bloemfontein 9301 RSA

Species＇ partitioning of resources remains one of the most integral components for understanding community assem- bly. Analysis of stable carbon and nitrogen isotopes in animal tissues has the potential to help resolve patterns of partitioning be- cause these proxies represent the individual＇s diet and trophic niche, respectively. Using free-ranging rodents in a southern Afri- can savanna as a model community, we find that syntopic species within habitats occupy distinct isotope niches. Moreover, spe- cies with strongly overlapping isotope niches did not overlap in their spatial distribution patterns, suggesting an underlying effect of competitive exclusion. Niche conservatism appears to characterize the behaviour of most species in our sample - with little or no observed changes across habitats - with the exception of one species, Mastomys coucha. This species displayed a generalist distribution, being found in similar abundances across a variety of habitats. This spatial pattern was coupled with a generalist isotope niche that shifted across habitats, likely in response to changes in species composition over the same spatial gradient. The case for M. coucha supports contentions that past competition effects played a significant evolutionary role in shaping community structures of today, including the absence of strong interspecific niche overlaps within particular habitats. Our study highlights the value of stable isotope approaches to help resolve key questions in community ecology, and moreover introduces novel ana- lytical approaches to quantifying isotope niche breadths and niche overlaps that are easily comparable with traditional metrices

关键词： Competition Diet Niche breadth Niche overlap Sterkfontein Valley

A look at the ASEAN-NDI: building a regional health R&D innovation network

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Infectious Diseases of Poverty 2014年第1期3卷 135-144页

作者： Jaime C Montoya Carina l Rebulanan nico Angelo C Parungao Bernadette Ramirez Department of Science and Technology-Philippine Council for Health Research and Development(DOST-PCHRD) Taguig CityPhilippines UNICEF/UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases(TDR) World Health OrganizationGenevaSwitzerland

Globally,there are growing efforts to address diseases through the advancement in health research and development(R&D),strengthening of regional cooperation in science and technology(particularly on product discovery and development),and implementation of the World Health Assembly Resolution 61.21(WHA61.21)on the Global Strategy and Plan of Action on Public Health,Innovation,and Intellectual Property(GSPA-PHI).As such,the Association of Southeast Asian Nations(ASEAN)is responding to this through the establishment of the ASEAN-Network for Drugs,Diagnostics,Vaccines,and Traditional Medicines Innovation(ASEAN-NDI).This is important in the ASEAN considering that infectious tropical diseases remain prevalent,emerging,and reemerging in the *** paper looks into the evolution of the ASEAN-NDI from its inception in 2009,to how it is at present,and its plans to mitigate public health problems regionally and even globally.

关键词： ASEAN-NDI Health research and development Infectious tropical diseases Innovation network Strategic business plan

The Fusarium oxysporum Avr2-Six5 Effector Pair Alters Plasmodesmatal Exclusion Selectivity to Facilitate Cell-to-Cell Movement of Avr2

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Molecular Plant 2018年第5期11卷 691-705页

作者： lingxue Cao Mila C. Blekemolen nico Tintor Ben J.C. Cornelissen Frank l.W. Takken Molecular Plant Pathology Swammerdam Institute for Life Science University of Amsterdam 1098 XH Amsterdam the Netherlands

Pathogens use effector proteins to manipulate their hosts. During infection of tomato, the fungus Fusarium oxysporum secretes the effectors Avr2 and Six5. Whereas Avr2 suffices to trigger I-2-mediated cell death in heterologous systems, both effectors are required for I-2-mediated disease resistance in tomato. How Six5 participates in triggering resistance is unknown. Using bimolecular fluorescence complementation assays we found that Avr2 and Six5 interact at plasmodesmata. Single-cell transformation revealed that a 2xRFP marker protein and Avr2-GFP only move to neighboring cells in the presence of Six5. Six5 alone does not alter plasmodesmatal transduction as 2xRFP was only translocated in the presence of both effectors. In SIX5-expressing transgenic plants, the distribution of virally expressed Avr2-GFP, and subsequent onset of I-2-mediated cell death, differed from that in wild-type tomato. Taken together, our data show that in the presence of Six5, Avr2 moves from cell to cell, which in susceptible plants contributes to virulence, but in I-2 containing plants induces resistance.

关键词： Plasmodesmata immunity effector pathogen Fusarium disease

Improving the radiological diagnosis of hepatic artery thrombosis after liver transplantation: Current approaches and future challenges

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Transplantation 2024年第1期14卷 1-8页

作者： Cristian lindner Raúl Riquelme Rodrigo San Martín Frank Quezada Jorge Valenzuela Juan P Maureira Martín Einersen Department of Radiology Faculty of MedicineUniversity of ConcepciónConcepción 4030000Chile Department of Radiology Hospital Clínico Regional Guillermo Grant BenaventeConcepción 4030000Chile Department of Statistics Catholic University of MauleTalca 3460000Chile Neurovascular Unit Department of RadiologyHospital Clínico Regional Guillermo Grant BenaventeConcepción 4030000Chile

Hepatic artery thrombosis(HAT)is a devastating vascular complication following liver transplantation,requiring prompt diagnosis and rapid revascularization treatment to prevent graft *** present,imaging modalities such as ultrasound,computed tomography,and magnetic resonance play crucial roles in diagnosing *** imaging techniques have improved sensitivity and specificity for HAT diagnosis,they have limitations that hinder the timely diagnosis of this *** this sense,the emergence of artificial intelligence(AI)presents a transformative opportunity to address these diagnostic *** development of machine learning algorithms and deep neural networks has demonstrated the potential to enhance the precision diagnosis of liver transplant complications,enabling quicker and more accurate detection of *** article examines the current landscape of imaging diagnostic techniques for HAT and explores the emerging role of AI in addressing future challenges in the diagnosis of HAT after liver transplant.

关键词： liver transplantation Postoperative complications Hepatic artery Thrombosis Radiology Artificial intelligence

Quark-Novae Ia in the Hubble diagram: implications for dark energy

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2014年第5期14卷 497-519页

作者： Rachid Ouyed nico Koning Denis leahy Jan E.Staff Daniel T.Cassidy Department of Physics and Astronomy University of Calgary 2500 University Drive NWCalgary Alberta T2N 1N4 Canada Department of Physics and Astronomy Macquarie University NSW 2109 Australia Department of Engineering Physics McMaster University Hamilton Ontario L8S 4L7 Canada

The accelerated expansion of the Universe was proposed through the use of Type-Ia supernovae （SNe） as standard candles. The standardization depends on an empirical correlation between the stretch/color and peak luminosity of the light curves. The use of Type-Ia SNe as standard candles rests on the assumption that their properties （and this correlation） do not vary with redshift. We consider the possibility that the majority of Type-Ia SNe are in fact caused by a Quark-Nova detonation in a tight neutron-star-CO-white-dwarf binary system, which forms a Quark-Nova Ia （QN-Ia）. The spin-down energy injected by the Quark-Nova remnant （the quark star） contributes to the post-peak light curve and neatly explains the observed correlation between peak luminosity and light curve shape. We demonstrate that the parameters describing QN-Ia are NOT constant in redshift. Simulated QN-Ia light curves provide a test of the stretch/color correlation by comparing the true distance modulus with that determined using SN light curve fitters. We determine a correction between the true and fitted distance moduli, which when applied to Type-Ia SNe in the Hubble diagram recovers the ΩM = 1 cosmology. We conclude that Type-Ia SNe observations do not necessitate the need for an accelerating expansion of the Universe （if the observed SNe Ia are dominated by QNe Ia） and by association the need for dark energy.

关键词： dark energy -- cosmology observations -- supernovae general