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排序方式: 共有18条查询结果,搜索用时 62 毫秒
1.
Understanding the drivers of phenological events is vital for forecasting species’ responses to climate change. We developed flexible Bayesian survival regression models to assess a 29‐year, individual‐level time series of flowering phenology from four taxa of Japanese cherry trees (Prunus spachiana, Prunus × yedoensis, Prunus jamasakura, and Prunus lannesiana), from the Tama Forest Cherry Preservation Garden in Hachioji, Japan. Our modeling framework used time‐varying (chill and heat units) and time‐invariant (slope, aspect, and elevation) factors. We found limited differences among taxa in sensitivity to chill, but earlier flowering taxa, such as P. spachiana, were more sensitive to heat than later flowering taxa, such as P. lannesiana. Using an ensemble of three downscaled regional climate models under the A1B emissions scenario, we projected shifts in flowering timing by 2100. Projections suggest that each taxa will flower about 30 days earlier on average by 2100 with 2–6 days greater uncertainty around the species mean flowering date. Dramatic shifts in the flowering times of cherry trees may have implications for economically important cultural festivals in Japan and East Asia. The survival models used here provide a mechanistic modeling approach and are broadly applicable to any time‐to‐event phenological data, such as plant leafing, bird arrival time, and insect emergence. The ability to explicitly quantify uncertainty, examine phenological responses on a fine time scale, and incorporate conditions leading up to an event may provide future insight into phenologically driven changes in carbon balance and ecological mismatches of plants and pollinators in natural populations and horticultural crops.  相似文献   
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Zipper-interacting protein kinase (ZIPK) regulates Ca(2+)-independent phosphorylation of both smooth muscle (to regulate contraction) and non-muscle myosin (to regulate non-apoptotic cell death) through either phosphorylation and inhibition of myosin phosphatase, the myosin phosphatase inhibitor CPI17, or direct phosphorylation of myosin light chain. ZIPK is regulated by multisite phosphorylation. Phosphorylation at least three sites Thr-180, Thr-225, and Thr-265 has been shown to be essential for full activity, whereas phosphorylation at Thr-299 regulates its intracellular localization. Herein we utilized an unbiased proteomics screen of smooth muscle extracts with synthetic peptides derived from the sequence of the regulatory phosphorylation sites of the enzyme to identify the protein kinases that might regulate ZIPK activity in vivo. Discrete kinase activities toward Thr-265 and Thr-299 were defined and identified by mass spectrometry as Rho kinase 1 (ROCK1). In vitro, ROCK1 showed a high degree of substrate specificity toward native ZIPK, both stoichiometrically phosphorylating the enzyme at Thr-265 and Thr-299 as well as bringing about activation. In HeLa cells, coexpression of ZIPK with ROCK1 altered the ROCK-induced phenotype of focused stress fiber pattern to a Rho-like phenotype of parallel stress fiber pattern. This effect was also dependent upon phosphorylation at Thr-265. Our findings provide a new regulatory pathway in smooth muscle and non-muscle cells whereby ROCK1 phosphorylates and regulates ZIP kinase.  相似文献   
3.
A case of a laryngeal extensive carcinoma determining a severe obstruction is reported, where the development of a monstrous adenopathy is followed by the regression of the initial tumour until complete laryngoscopical disappearance, as well as of obstructive and general symptoms. Cytological and histological examinations of the above-mentioned lymph node demonstrated (besides metastatic cells) a peculiar cellular reaction, similar to rhinoscleroma, which represented an original anti-carcinoma defensive mode. The medical importance of this very rare case is discussed and the probable immune origin of this reactive cellular complex is explained by analogy with "Hodgkinom", where granuloma are the immune response of the body against Sternberg-Reed cell.  相似文献   
4.
Aquatic macrophytes are one of the biological quality elements in the Water Framework Directive (WFD) for which status assessments must be defined. We tested two methods to classify macrophyte species and their response to eutrophication pressure: one based on percentiles of occurrence along a phosphorous gradient and another based on trophic ranking of species using Canonical Correspondence Analyses in the ranking procedure. The methods were tested at Europe-wide, regional and national scale as well as by alkalinity category, using 1,147 lakes from 12 European states. The grouping of species as sensitive, tolerant or indifferent to eutrophication was evaluated for some taxa, such as the sensitive Chara spp. and the large isoetids, by analysing the (non-linear) response curve along a phosphorous gradient. These thresholds revealed in these response curves can be used to set boundaries among different ecological status classes. In total 48 taxa out of 114 taxa were classified identically regardless of dataset or classification method. These taxa can be considered the most consistent and reliable indicators of sensitivity or tolerance to eutrophication at European scale. Although the general response of well known indicator species seems to hold, there are many species that were evaluated differently according to the database selection and classification methods. This hampers a Europe-wide comparison of classified species lists as used for the status assessment within the WFD implementation process.  相似文献   
5.
The Water Framework Directive (WFD 2000) defines macrophytes as one of the biological groups required for the ecological assessment of European surface waters. Several indices for macrophyte assessment have been proposed or are currently in use by different European states. As a first step towards performing an intercalibration of these indices a common dataset was developed. This dataset contains abundance data on 789 macrophyte species from 316 different lake sites in ten European countries. Various common species and genera were identified as indicators of reference and impacted conditions within the dataset. Cluster analysis of macrophyte data, supported by non-metric multidimensional scaling, indicated that clusters formed were more reflective of their source country rather than lake type. This might be caused by differences in regional climate, biogeography, monitoring techniques, or a combination of these factors. A total of six national indices were applied to assign quality classes to the lakes. However, this produced results that often differed by one or two quality classes for the same site. We foresee that a more precise intercalibration exercise is necessary, and it should be based on more detailed data considering both seasonality and the latitudinal differences within the area covered.  相似文献   
6.
Satyrium favonius ontario: (W. H. Edwards) (Lepidoptera: Lycaenidae) is considered to be a rare butterfly in the northeastern United States. It receives legal protection in the state of Massachusetts as a Species of Special Concern. We studied the ecology and natural history of a colony of S. f. ontario at Great Blue Hills Reservation in Canton, Massachusetts. In addition, we assembled a database of confirmed S. f. ontario occurrences (n?=?362) and used this along with climate and oak abundance data to build a species distribution model for the northeastern portion of the butterfly’s range in the United States. The model predicts that essentially the entirety of southern New England is suitable for the species, and thus its modeled distribution extends well north of all documented colonies/localities. Just two climate variables, precipitation seasonality and minimum temperature of the coldest month, explained 95% of the model and largely determined relative suitability predictions. We make the case that the hairstreak is a canopy-dwelling insect that sporadically makes ground-level visits, and that its assumed regional rarity is due to detection difficulties rather than demographic rarity. While the butterfly may be imperiled and worthy of legal protection in portions of its range, we question the validity of population estimates and necessity of conservation efforts based on ground-level adult sightings, and recommend larval sampling using burlap bands as a more reliable method to census this butterfly. We also discuss the possibility that other Satyrium and more distantly related hairstreaks (e.g., Callophrys hesseli and Parrhasius m-album) may be additional examples of temperate, canopy-based butterflies.  相似文献   
7.
A convenient enantioselective approach for the pinacol coupling of 1‐acetylazulene involving easily accessible (R)‐ or (S)‐BINOLs as chiral additive is reported. This supposes the preformation of the chiral titanium–BINOL complex in 1:2 ratio and subsequent reduction with zinc when, 2,3‐di(azulen‐1‐yl)butane‐2,3‐diol can be isolated in around 60% enantiomeric excess. The absolute configuration of the isolated enantiomers was assigned by comparison of the experimental and Boltzmann‐weighted calculated VCD and ECD spectra and assigned as (+)‐(2S;3S)‐di(azulen‐1‐yl)butane‐2,3‐diol. Chirality 27:826–834, 2015. © 2015 Wiley Periodicals, Inc.  相似文献   
8.
The impact of exogenic testosterone (T): 1.5 and 3.0 mg/kg.bw) and 19-nortestosterone 17-decanoate (ND): 1.5 and 7.5 mg/kg.bw) in castrated male rats was evaluated based on: (a) weight increase of the androgen target tissues, respecting the Hershberger methodology; (b) the 17α and β-testosterone, 17 α and β-estradiol and 17 α and β-nortestosterone levels using the GC-MS/MS technique; and (c) observation of the serum free thyroxine levels (T4). Results revealed that T and ND significantly increased the weight of androgen target tissues as follows: ND was more influential on seminal vesicles, levator ani-bulbocavernosus muscle (LABC) and Cowper''s glands and T (at a dose of 3.0 mg/kg.bw) influenced the weight of the ventral prostate and glans penis. Serum samples analyzed for steroid hormone levels showed the presence of 17β-testosterone, 17β-estradiol and 17β-nor-testosterone, in castrated male rats injected with testosterone and nortestosterone, but no significant differences were found between thyroid responses and thyroid hormone levels. The results of this research proved the disrupting activity of T and ND when administered in high doses and the useful application of the Hershberger bioassay in the case of ND.  相似文献   
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