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61.
Much of the recent changes in North American climate have occurred during the winter months, and as result, overwintering birds represent important sentinels of anthropogenic climate change. While there is mounting evidence that bird populations are responding to a warming climate (e.g., poleward shifts) questions remain as to whether these species‐specific responses are resulting in community‐wide changes. Here, we test the hypothesis that a changing winter climate should favor the formation of winter bird communities dominated by warm‐adapted species. To do this, we quantified changes in community composition using a functional index – the Community Temperature Index (CTI) – which measures the balance between low‐ and high‐temperature dwelling species in a community. Using data from Project FeederWatch, an international citizen science program, we quantified spatiotemporal changes in winter bird communities (= 38 bird species) across eastern North America and tested the influence of changes in winter minimum temperature over a 22‐year period. We implemented a jackknife analysis to identify those species most influential in driving changes at the community level and the population dynamics (e.g., extinction or colonization) responsible for these community changes. Since 1990, we found that the winter bird community structure has changed with communities increasingly composed of warm‐adapted species. This reshuffling of winter bird communities was strongest in southerly latitudes and driven primarily by local increases in abundance and regional patterns of colonization by southerly birds. CTI tracked patterns of changing winter temperature at different temporal scales ranging from 1 to 35 years. We conclude that a shifting winter climate has provided an opportunity for smaller, southerly distributed species to colonize new regions and promote the formation of unique winter bird assemblages throughout eastern North America.  相似文献   
62.
Summary Under the ?Bois plus? scheme, the CTBA is currently developing a third party certification, based on the Scrivener law, with the aim of defending the consumers' interests. At this early stage, wood preservatives and treated wood are checked for the efficacy of treatments in order to ensure the stability and security of works in buildings and civil engineering. According to the different classes of risks in service, ?Bois plus? provides the most adeguate level of protection. In the close future, the industry is planning to incorporate, with the help of the CTBA and experts, health criteria within the frame of the ?Bois plus? certification scheme. The means could beSafety indexes, which are objectives of quality for professionals.Safety indexes are concentrations of substances in wood which can be taken as safe for humans and the general environment, while still toxic for the wood pests. This attractive experience aims to make with the brandname ?Bois plus? a synonym of efficacy and safety. This approach meets the essential requirements 1, 3, 4 of the 89/106 EEC directive: mechanical resistance and stability/hygiene, health and environment/safety in use.  相似文献   
63.
An objective, quantifiable index of structural biodiversity that could be rapidly obtained with reduced or no field effort is essential for the use of structure as universal ecological indicator for ecosystem management. Active remote sensing provides a rapid assessment tool to potentially guide land managers in highly dynamic and spatially complex landscapes. These landscapes are often dependent on frequent disturbance regimes and characterized by high endemism.We propose a modified Shannon–Wiener Index and modified Evenness Index as stand structural complexity indices for surrogates of ecosystem health. These structural indices are validated at Tall Timbers Research Station the site of one of the longest running fire ecology studies in southeastern U.S. This site is dominated by highly dynamic pine-grassland woodlands maintained with frequent fire. Once the dominant ecosystem in the Southeast, this woodland complex has been cleared for agriculture or converted to other cover types, and depends on a frequent (1- to 3-year fire return interval) low- to moderate-intensity fire regime to prevent succession to mixed hardwood forests and maintain understory species diversity. Structural evaluation of the impact of multiple disturbance regimes included height profiles and derived metrics for five different fire interval treatments; 1-year, 2-year, 3-year, mixed fire frequency (a combination of 2- and 4-year fire returns), and fire exclusion. The 3-dimensional spatial arrangement of structural elements was used to assess hardwood encroachment and changes in structural complexity. In agreement with other research, 3-year fire return interval was considered to be the best fire interval treatment for maintaining the pine-grassland woodlands, because canopy cover and vertical diversity indices were shown to be statistically higher in fire excluded and less frequently burned plots than in 1- and 2-year fire interval treatments. We developed a LiDAR-derived structural diversity index, LHDI, and propose that an ecosystem-specific threshold target for management intervention can be developed, based on significant shifts in structure and composition using this new index.Structural diversity indices can be valuable surrogates of ecosystem biodiversity, and ecosystem-specific target values can be developed as objective quantifiable goals for conservation and ecosystem integrity, particularly in remote areas.  相似文献   
64.
《Médecine Nucléaire》2014,38(1):21-30
Since its introduction 10 years ago, the urinary PCA3 test was evaluated in several studies that allowed demonstration of its diagnostic value when predicting prostate biopsy outcome. Its good specificity, notably when compared to seric PSA, offers to the urologist the opportunity to better evaluate whether prostate biopsies are warranted, especially in patients with at least one set of previous negative biopsies. Several points remain to be determined such as its true influence on prostate decision making in clinical practice and the resulting medico-economic benefit. The place of the urinary PCA3 test among other developing prostate cancer biomarkers, notably PHI index and urinary TMPRSS2:ERG fusions, has also to be defined.  相似文献   
65.
ABSTRACT

Background: The disruption of circadian rhythm has been found to associate with obesity in vivo and in vitro. Sleep duration, eating habits, total feeding time, and nightshift work can also affect circadian rhythms. This study investigated the association between misalignment of circadian rhythm and obesity in Korean men, using a cross-sectional database.

Methods: This study used data from the Korean National Health and Nutrition Examination Survey (KNHANES), whose study population was 3,658 men aged 18 to 60 years. General and abdominal obesity was defined as a body mass index (BMI) ≥ 25 kg/m2 and waist circumference ≥ 90 cm, respectively. Circadian rhythm factors were determined with a self-report questionnaire and included breakfast frequency, sleep duration, and work time. Frequency of breakfast was divided into regular breakfast (five to seven times a week) and irregular breakfast (less than five times a week). Sleep duration was divided into less than 7 hours, 7–9 hours, and over 9 hours. Working time was defined as day/evening, night shift, and other type. The adjusted odds ratios (aORs) and 95% confidence intervals (CIs) for general and abdominal obesity were calculated using multivariable logistic regression according to the number of factors that disturb the circadian rhythm.

Results: Participants with 1 (aOR 1.34, 95% Cl 1.10–1.61) and ≥2 (aOR 1.62, 95% Cl 1.29–2.05) factors disturbing circadian rhythms were associated with elevated risk for general obesity. Similarly, those with 1 (aOR 1.33, 95% Cl 1.09–1.63) and ≥2 (aOR 1.70, 95% Cl 1.32–2.20) factors had elevated risk for abdominal obesity.

Conclusions: Factors disturbing the circadian rhythm were associated with general and abdominal obesity. Additional studies are needed, and associations with metabolic diseases should be investigated.  相似文献   
66.
This communication discusses the discovery of novel reverse tricyclic pyridones as inhibitors of Janus kinase 2 (JAK2). By using a kinase cross screening approach coupled with molecular modeling, a unique inhibitor–water interaction was discovered to impart excellent broad kinase selectivity. Improvements in intrinsic potency were achieved by utilizing a rapid library approach, while targeted structural changes to lower lipophilicity led to improved rat pharmacokinetics. This multi-pronged approach led to the identification of 31, which demonstrated encouraging rat pharmacokinetics, in vivo potency, and excellent off-target kinase selectivity.  相似文献   
67.

1. 1. In this short review, previous studies regarding the modeling of lactate (La) response to exercise and its application to endurance training have been summarized.

2. 2. Additionally the result of a recent study by the present authors are shown.

3. 3. Several models for La response to step and ramp exercise are already proposed and deductions derived from them are used for practical purposes such as the prediction of race performance in middle-and long-distance runners as well as for construction of their training regimens.

4. 4. Only a limited number of models however have tried to quantify whole body La kinetics to exercise in humans concomitantly with describing physiological mechanisms underlying the observed phenomenon.

5. 5. In a recent study described further in this paper a 2 compartment model was used for the purpose of clarifying the current “La production vs degradation” controversy during La adaptation to training.

6. 6. It was determined from this investigation that the La metabolic clearance rate during recovery is enhanced by the endurance training.

7. 7. This is in accordance with another recent observation of an increased La metabolic clearance rate at high absolute work rates and all relative work rates during exercise.

Author Keywords: Lactate kinetics; training; physiological modeling  相似文献   

68.
Drug resistance is a critical obstacle to effective treatment in patients with chronic myeloid leukemia. To understand the underlying resistance mechanisms in response to imatinib mesylate (IMA) and adriamycin (ADR), the parental K562 cells were treated with low doses of IMA or ADR for 2 months to generate derivative cells with mild, intermediate, and severe resistance to the drugs as defined by their increasing resistance index. PulseDIA-based (DIA [data-independent acquisition]) quantitative proteomics was then employed to reveal the proteome changes in these resistant cells. In total, 7082 proteins from 98,232 peptides were identified and quantified from the dataset using four DIA software tools including OpenSWATH, Spectronaut, DIA-NN, and EncyclopeDIA. Sirtuin signaling pathway was found to be significantly enriched in both ADR-resistant and IMA-resistant K562 cells. In particular, isocitrate dehydrogenase (NADP(+)) 2 was identified as a potential drug target correlated with the drug resistance phenotype, and its inhibition by the antagonist AGI-6780 reversed the acquired resistance in K562 cells to either ADR or IMA. Together, our study has implicated isocitrate dehydrogenase (NADP(+)) 2 as a potential target that can be therapeutically leveraged to alleviate the drug resistance in K562 cells when treated with IMA and ADR.  相似文献   
69.
大型煤电基地(CEBs)是我国煤基能源和材料集中开发区域和国家能源战略安全重要支撑,合理评价CEBs开发生态影响是CEBs可持续协调开发、科学管理中的难点问题。研究将CEBs开发视为系统工程,与自然生态系统(NES)相关联,深入研究大型煤电基地生态系统(CEBES)的驱动行为、内在结构及主要关系、生态影响途径、生态累积过程和生态累积效应及阈值分析方法。基于CEBs空间和功能定位提出CEBs的概念、内涵和特点,融合构建的CEBES涵盖到自然资源、能源开发行为(煤、电等)、其他人类活动(农、牧、城)和大气、水、土壤及生物域;研究表明CEBES的生态累积状态受三种行为驱动和影响(自然行为、能源开发行为和其他人类活动),通过融合、传导和辐射耦合作用,表现为生态要素损伤、系统结构变化和系统状态失衡三级状态,生态累积具有影响多态性、空间多尺度和过程渐变性特点;明确了生态累积过程、累积效应和阈值及其相互关系,引入反映生态影响累积程度的生态损伤系数,提出四类生态阈值(生态要素、内部结构、系统状态和行为调控);基于系统性和实用性筛选反映生态累积相对状态的60项指标,构建具有“三力”驱动、分区要素耦合和系...  相似文献   
70.
彭加加  徐丽萍  曹翠 《生态学报》2022,42(20):8265-8275
冰川景观变化是全球环境和气候变化的共同"指示器"。随着全球气候变化加剧,干旱和半干旱地区的冰川景观将进一步变化。科学评估冰川景观格局时空演变特征,为应对冰川景观变化及其影响提供科学参考。基于1991-2017年Landsat TM/ETM+/OLI遥感影像,采用监督分类方法获取叶尔羌河流域冰川景观时空格局及变化数据,利用景观格局指数、质心迁移模型、分形维数等方法分析近26年叶尔羌河流域冰川景观格局时空演变特征。结果表明:(1)1991-2017年叶尔羌河流域冰川斑块面积呈消减趋势,但有所减缓,共减少799.50 km2(-13.09%)。冰川斑块面积消减主要集中在海拔5400-5800 m之间,相较之下,海拔4400 m以下的区域冰川斑块面积消减率最高,达63.68%;不同坡度冰川景观消减率存在差异,陡坡冰川斑块面积消减率最高(15.98%),急陡坡消减率最低(2.87%);阴阳两坡冰川景观均呈消减趋势,阳坡冰川斑块面积消减速率显著高于阴坡。(2)近26年来,叶尔羌河流域冰川斑块数量、最大斑块指数均减小,而平均形状指数、平均周长面积比、分裂指数均增加,表明冰川景观不断消减,破碎化程度增加。(3)研究期间,叶尔羌河流域冰川景观质心发生迁移,整体呈现东北偏移趋势。(4)通过分形理论对叶尔羌河流域冰川景观空间结构特征进行分析表明,该流域冰川景观消减率略微降低,但仍然处于持续消融状态。  相似文献   
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