川西亚高山暗针叶林恢复过程中岷江冷杉天然更新状况及其影响因子

在川西亚高山米亚罗林区海拔3 100~3 600 m阴坡、半阴坡, 以立地条件基本一致的箭竹和藓类林型不同恢复阶段(20~40 a生的箭竹阔叶林、50 a生的箭竹针阔混交林、160~200 a生的箭竹原始暗针叶老龄林; 20~40 a生的藓类阔叶林、50 a生的藓类针阔混交林、160~200 a生的藓类原始暗针叶老龄林)的群落为研究对象, 共设置了50个样方(20 m×20 m), 采用空间代时间的方法分析了岷江冷杉(Abies faxoniana)的天然更新状况, 并采用通径分析法对其影响因子进行分析。结果表明: 箭竹和藓类两种森林类型岷江冷杉幼苗、幼树和小树的密度偏低。对于箭竹林型不同恢复阶段, 岷江冷杉幼苗密度＜幼树密度＜小树密度; 对于藓类林型不同恢复阶段, 藓类阔叶林幼树密度大于幼苗和小树密度, 藓类针阔混交林小树密度大于幼苗和幼树密度, 而藓类原始暗针叶老龄林幼苗密度大于幼树和小树密度。藓类林型岷江冷杉天然更新状况好于箭竹林型。对箭竹林型而言, 影响岷江冷杉天然更新的关键因子为母树密度、倒木蓄积量、箭竹盖度和苔藓层厚度, 其中母树密度和倒木蓄积量对岷江冷杉天然更新起着促进作用, 箭竹盖度和苔藓层厚度对岷江冷杉天然更新起着阻碍作用; 对于藓类林型而言, 影响岷江冷杉天然更新的关键因子为灌木盖度和苔藓层厚度。灌木和苔藓有利于幼苗的发生, 但不利于幼苗向幼树、小树的过渡。     

Phylogeographic history of Patagonian lizards of the Liolaemus elongatus complex (Iguania: Liolaemini) based on mitochondrial and nuclear DNA sequences

In this study, we present a phylogeographic analysis of a group of lizards distributed in north‐western Patagonia, the Liolaemus elongatus complex. We sequenced 581 individuals for one mitochondrial gene (cytochrome‐b), and for a subset, we sequenced another mitochondrial gene (12S rRNA) and two nuclear genes: kinesin family member 24 (KIF24) and the anonymous nuclear locus LDAB1D. We estimated gene trees, mitochondrial and nuclear haploytpe networks, standard molecular diversity indices, genetic distances between lineages and Bayesian skyline plots. Our results provide evidence for recognition of seven species previously described within the L. elongatus complex: Liolaemus antumalguen, Liolaemus chillanensis, Liolaemus carlosgarini, Liolaemus burmeisteri, Liolaemus smaug, Liolaemus elongatus and Liolaemus crandalli, but we did not find sufficient evidence to support Liolaemus choique, Liolaemus shitan or Liolaemus sp. 6 as distinct species. We identified four candidate species (Liolaemus sp. 1, Liolaemus sp. 2, Liolaemus sp. 3 and Liolaemus sp. 7), and we discuss evolutionary processes that may have contributed to the origin of these lineages and their taxonomic and conservation implications.     

Evaluating the Usefulness of Compulsory Licensing in Developing Countries: A Comparative Study of Thai and Brazilian Experiences Regarding Access to Aids Treatments

While compulsory licensing (CL) is described in the TRIPS agreement as flexibility to protect public health by improving access to medicines in developing countries, a recent literature contends adversely that CL may harm public health. Therefore, this article intends to evaluate the usefulness of CL in the South through the prism of obligations and goals entrusted to patent holders (the effective and non‐abusive exploitation of patents in order to achieve industrial and health developments) and in light of experiences in Thailand and Brazil regarding access to antiretroviral drugs. In this way, it shows that the obligations assigned to patent holders were better served by the recipients of CL and brought significant health and industrial benefits in the two high middle‐income countries. In particular, CL allowed the scaling‐up of free and universal access to antiretroviral drugs by assuring the financial sustainability of these public health programs endangered by monopolistic practices from patent holders.     

Informed Consent in Health Research: Challenges and Barriers in Low‐and Middle‐Income Countries with Specific Reference to Nepal

Obtaining ‘informed consent’ from every individual participant involved in health research is a mandatory ethical practice. Informed consent is a process whereby potential participants are genuinely informed about their role, risk and rights before they are enrolled in the study. Thus, ethics committees in most countries require ‘informed consent form’ as part of an ethics application which is reviewed before granting research ethics approval. Despite a significant increase in health research activity in low‐and middle‐income countries (LMICs) in recent years, only limited work has been done to address ethical concerns. Most ethics committees in LMICs lack the authority and/or the capacity to monitor research in the field. This is important since not all research, particularly in LMICs region, complies with ethical principles, sometimes this is inadvertently or due to a lack of awareness of their importance in assuring proper research governance. With several examples from Nepal, this paper reflects on the steps required to obtain informed consents and highlights some of the major challenges and barriers to seeking informed consent from research participants. At the end of this paper, we also offer some recommendations around how can we can promote and implement optimal informed consent taking process. We believe that paper is useful for researchers and members of ethical review boards in highlighting key issues around informed consent.     

Intercontinental disjunctions between eastern Asia and western North America in vascular plants highlight the biogeographic importance of the Bering land bridge from late Cretaceous to Neogene

This review shows a close biogeographic connection between eastern Asia and western North America from the late Cretaceous to the late Neogene in major lineages of vascular plants (flowering plants, gymnosperms, ferns and lycophytes). Of the eastern Asian–North American disjuncts, conifers exhibit a high proportion of disjuncts between eastern Asia and western North America. Several lineages of ferns also show a recent disjunct pattern in the two areas. In flowering plants, the pattern is commonly shown in temperate elements between northeastern Asia and northwestern North America, as well as elements of the relict boreotropical and Neogene mesophytic and coniferous floras. The many cases of intercontinental biogeographic disjunctions between eastern Asia and western North America in plants supported by recent phylogenetic analyses highlight the importance of the Bering land bridge and/or the plant migrations across the Beringian region from the late Cretaceous to the late Neogene, especially during the Miocene. The Beringian region has permitted the filtering and migration of certain plant taxa since the Pliocene after the opening of the Bering Strait, as many conspecific taxa or closely related species occur on both sides of Beringia.     

Factors affecting seasonal variations in demersal fish assemblages at an ecocline in a tropical–subtropical estuary

Seasonal changes of fish species composition in terms of biomass, density and number of species in three areas of the main channel of the Paranaguá Estuary (axis east–west) are described in relation to seasonal fluctuations in salinity, water temperature and dissolved oxygen in the main channel. Two hundred and thirty‐four samples were collected monthly, between July 2000 and June 2001, in the main channel. Seventy‐nine species of 29 families were captured with a total estimated mean density and biomass of 1513 individuals ha^?1 and 34 kg ha^?1, respectively. The number of species and total mean density differed significantly among areas and seasons, but the total mean biomass differed only significantly throughout the ecocline (areas) of the Paranaguá Estuary. For the most abundant species, the mean densities of Stellifer rastrifer, Aspistor luniscutis, Menticirrhus americanus, Sphoeroides testudineus, Cynoscion leiarchus and Symphurus tesselatus (with the exception of Cathorops spixii and Genidens genidens) differed significantly among seasons. The mean biomass of these species, with the exception of G. genidens, S. rastrifer, A. luniscutis and S. testudineus, also differed significantly for the factor seasons. Area was a significant factor for the eight most abundant species (density and biomass), except S. testudineus (density), G. genidens, C. leiarchus and S. tesselatus (biomass). The season v. area interaction term was significant for C. leiarchus (density). Most of these differences occurred during the rainy season when fishes concentrated principally in the middle of the estuary, where the salinity remained stable. It is suggested that the salinity stability in the middle of the estuary is the main reason why the most estuarine resident fish species move downstream and remain there, regardless of the increased freshwater runoff. Moreover, canonical correspondent analysis output detected that during the late rainy season, the variable dissolved oxygen (P < 0·01) was the most important environmental variable, responsible for structuring patterns of fishes assemblages in the west–east axis of Paranaguá Estuary. During the end of the dry season, both salinity (P < 0·01) and dissolved oxygen (P < 0·05) were responsible for this ecological feature in the estuary. Finally, it was possible to detect that juveniles and adults of some important species respond differently to seasonal fluctuations of the ecocline‐determining environmental factors. This behaviour is suggested as a strategy to avoid competition and predation during the rainy season in the middle estuary. The Paranaguá Estuary did not fit with the pre‐existing models described in the tropical and subtropical estuarine fish literature since its main channel fish assemblages remained within its bounds even during the rainy season.     

The recent colonization of south Brazil by the Azores chromis Chromis limbata

The damselfish Chromis limbata is native to the Macaronesian Archipelagos (Azores, Madeira and Canaries) and the western coast of Africa between Senegal and Angola. During the austral summers of 2008 and 2009 the species was recorded for the first time in the south‐western Atlantic Ocean around Campeche and Xavier Islands, in Florianópolis, Santa Catarina State, Brazil. Here, the progression of C. limbata in southern Brazilian waters is described using visual counts and genetic surveys and changes in the density of the native congener Chromis multilineata were also investigated. Underwater visual censuses of both Chromis species were carried out from 2009 to 2014. Chromis limbata tissue samples were collected and the mtDNA control region was sequenced and compared with mtDNA haplotypes from the natural range to confirm species identity, compare genetic diversity and to infer connectivity between newly established Brazilian populations. The Brazilian population of C. limbata increased significantly over the past 5 years and the effect on C. multilineata is still an open question, longer time‐series data will be necessary to clarify possible interactions. The molecular analyses confirmed species identity, revealed strong haplotype connectivity among Brazilian study sites and showed a low genetic diversity in Brazil when compared with the native populations, suggesting few individuals started the invasion. Four hypotheses could explain this colonizing event: C. limbata was released by aquarium fish keepers; larvae or juveniles were transported via ship ballast water; the species has rafted alongside oil rigs; they crossed the Atlantic Ocean through normal larval dispersal or naturally rafting alongside drifting objects. The rafting hypotheses are favoured, but all four possibilities are plausible and could have happened in combination.     

Restoring Sage‐grouse nesting habitat through removal of early successional conifer

Conifer woodlands have expanded into sagebrush (Artemisia spp.) ecosystems and degrade habitat for sagebrush obligate species such as the Greater Sage‐grouse (Centrocercus urophasianus). Conifer management is increasing despite a lack of empirical evidence assessing outcomes to grouse and their habitat. Although assessments of vegetation recovery after conifer removal are common, comparisons of successional trends with habitat guidelines or actual data on habitat used by sage‐grouse is lacking. We assessed impacts of conifer encroachment on vegetation characteristics known to be important for sage‐grouse nesting. Using a controlled repeated measures design, we then evaluated vegetation changes for 3 years after conifer removal. We compared these results to data from 356 local sage‐grouse nests, rangewide nesting habitat estimates, and published habitat guidelines. We measured negative effects of conifer cover on many characteristics important for sage‐grouse nesting habitat including percent cover of forbs, grasses, and shrubs, and species richness of forbs and shrubs. In untreated habitat, herbaceous vegetation cover was slightly below the cover at local nest sites, while shrub cover and sagebrush cover were well below cover at the nest sites. Following conifer removal, we measured increases in herbaceous vegetation, primarily grasses, and sagebrush height. Our results indicate that conifer abundance can decrease habitat suitability for nesting sage‐grouse. Additionally, conifer removal can improve habitat suitability for nesting sage‐grouse within 3 years, and trajectories indicate that the habitat may continue to improve in the near future.     

川西卧龙国家级自然保护区树木生长对气候响应的时间稳定性评估

根据川西卧龙地区岷江冷杉(Abies faxoniana)的年轮宽度资料, 分析了该地区树木生长特征及对气候响应在最近53年(1956-2008年)的异质性特征。结果表明, 在1956-1976年时段, 树木生长速率较快, 晚冬至早春(1月到4月)温度对树木生长有着明显的促进作用, 而春末5月份的高温对于树木生长有限制性影响, 而与日照时数关系不大; 在1977-2008年时段, 树轮生长主要受冬季(11月到1月)低温的限制, 另外, 日照时数对于树木生长的限制性影响明显增强。秋季到早冬(9-12月)降水在两个时段上对树木生长均有一定的限制性影响。树轮指数在1956-1976年时段与温度序列吻合较好, 而在1977-2008年时段树轮指数明显偏低, 与温度序列出现了明显的分离。1977-2008年时段内云层覆盖量增加导致太阳辐射量显著下降, 进而树木可利用的光合有效辐射也相应地降低, 这可能是树木生长速率在此时期明显较慢的主要原因。     

Corynebacterium pseudodiphtheriticum isolated from relevant clinical sites of infection: a human pathogen overlooked in emerging countries

Aims:  To examine the occurrence of and to determine the antimicrobial susceptibility of Corynebacterium pseudodiphtheriticum among patients with bacterial infections at a teaching hospital.
Methods and Results:  A total of 113 Coryne. pseudodiphtheriticum strains identified by conventional biochemical methods and API-Coryne System were recovered from patients from different age groups: 65·48% adults (18 to ≤59 years old), 9·73% aged (≥60 years old); 14·15% infants (<18 years old); 4·42% newborns (0–7 days). Micro-organisms were mostly related to infections in the urinary (29·2%) and respiratory tracts (27·45%) and intravenous sites (18·6%). Clinical samples were obtained only from 32·7% patients (26 adults, four aged, four infants and three newborns) presenting at least one of the predisposing conditions: end-stage renal disease; renal transplant; AIDS and Mycobacterium tuberculosis infection; cancer, hepatic cirrhosis; haemodialysis and catheter use. Antimicrobial susceptibility tests identified multiresistant phenotypes. Most strains (>50%) were resistant to oxacillin, erythromycin and clindamycin.
Conclusions:  Despite significant differences in age and functional status of patients Coryne. pseudodiphtheriticum may be implicated as a cause of respiratory and nonrespiratory human infections.
Significance and Impact of the Study:  Data are valuable for practitioners indicating the occurrence of multiresistant phenotypes and the possibility of severe infections due to Coryne. pseudodiphtheriticum , a pathogen usually overlooked in emerging countries.