检索结果-南通市图书馆

Demographic trends and climate over 35 years in the Barro Colorado 50 ha plot

在线全文

学校读者我要写书评

暂无评论

Forest Ecosystems 2017年第4期4卷 273-285页

作者： richard Condit Rolando pérez Suzanne Lao Salomón Aguilar Stephen p. Hubbell Field Museum of Natural History 1400 S

Background： The first three censuses of the 50-ha plot at Barro Colorado Island spanned an unusually harsh dry season during the 1983 El Nitro. By the early 1990s, we had documented increases in tree mortality, tree growth, and large population fluctuations of many species during the 1982-1985 census interval. At the time, we asserted that increasing drought frequency would greatly affect the forest. With the benefit of five more censuses at Barro Colorado from 1995-2015, we can now put the 1980 conditions in a longer perspective and test the hypothesis that increasing droughtiness has continued to change the forest. Methods： A 50-ha forest plot on Barro Colorado Island was censused eight times, in 1982 and every five years since 1985. All free-standing woody stems were measured, mapped, and identified in each census. Results： 1） The period 1982-1992 included several extreme dry seasons, not just 1983, but since then there have been few such droughts. 2） Dbh growth declined from a peak in the early 1980s to its lowest in the early 1990s. From 1995-2015 it increased slightly, but not returning to the initial peak. Nearly every species and all dbh categories followed the same pattern. 3） The elevated stand-wide mortality rate of large trees during the 1982-1985 drought has not returned, and most individual species showed the same pattern of elevated mortality in the 1980s followed by low and fairly stable mortality after 1990. 4） Sapling mortality declined after 198,5, but rose again in the late-90s, so the 1980s drought period no longer looks unusual. Mortality of individual species＇ saplings fluctuated erratically, including cases where mortality during the drought was lower than after. 5） population sizes of individual species fluctuated in all possible directions. Some species declined precipitously during the drought, then recovered, but others did not recover. Other species increased in abundance during the drought. Conclusions＂ Droughts of the 1980s elevated tr

关键词： Demographic trends climate

Solvothermal preparation of iron phosphonate cages

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2012年第6期55卷 910-913页

作者： WINpENNY richard E. p. School of Chemistry University of Manchester Manchester M13 9PL United Kingdom The photon Science Institute University of Manchester Manchester M13 9PL United Kingdom

Three new iron（Ⅲ） phosphonate cage-like complexes with [Fe4], [Feg] and [Fe14] cores have been synthesized by solvothermal reaction with various starting materials. Magnetic studies show overall antiferromagnetic i... 详细信息

关键词： polynuclear iron coordination phosphonate magnetic properties

Efficacy of Detoxsan~? powder on diarrhea caused by gastrointestinal neuroendocrine tumors

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2019年第17期25卷 2133-2143页

作者： Thomas Langbein Wilfried Dathe Anika Deuerling richard p Baum Theranostics Center for Molecular Radiotherapy and Molecular Imaging Zentralklinik Bad Berka Scientific Managment Heck Bio-Pharma GmbH

BACKGROUND patients with neuroendocrine tumors(NETs) of the gastrointestinal tract suffer frequently from chronic diarrhea. A well characterized medical advice containing zeolite(Detoxsan~? powder) was applied to patients suffered from therapyrefractory diarrhea either by its frequency or by watery stool, despite receiving standard pharmacotherapy according to the guidelines for carcinoid syndrome and comorbidities. Detoxsan~? powder acts as an adsorbent and might reduce significantly symptoms of diarrhea in patients suffering from *** To overcome the therapy-refractory diarrhea of patients with NETs by the zeolite containing medical advice Detoxsan~? *** A total of 20 patients(12 female and 8 male) suffering from diarrhea either by its frequency or from watery stool caused by NETs were included. In each patient,the diagnosis had been confirmed by histology and somatostatin receptors expression proven by positron emission tomography/computed tomography using Ga-68-labeled somatostatin analogs. All patients received standard-of-care pharmacotherapy and were additionally given Detoxsan~? powder as an extemporaneous drug containing 90% natural Cuban zeolite and 10% magnesium aspartate. Recommended daily dosage ranges between 3 g once to three times per day. Each day dose and bowel movements were documented by the patients themselves in a pre-defined table. Additionally to the bowel movements quantitative determinations of serotonin, urea, creatinine and single ions were performed within the serum of the patients by commercially available equipment used as a matter of routine in the *** All patients enrolled in this pilot study did not only suffer from NETs, but also from comorbidities and treatment-resistant diarrhea. There was insufficient control of diarrhea, most probably due to the secretion of hormones like serotonin produced by the slowly growing and highly differentiated NETs. All patients only took Detoxsan~? powder as an antidiarrhea

关键词： Neuroendocrine tumor Diarrhea Carcinoid syndrome Treatment Clinoptilolite Mordenite Zeolite

Incorporating novelty and novel ecosystems into restoration planning and practice in the 21st century

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Ecological processes 2013年第1期2卷 175-182页

作者： Michael p perring Rachel J Standish richard J Hobbs Ecosystem Restoration and Intervention Ecology Research Group School of Plant BiologyThe University of Western Australia35 Stirling HighwayCrawleyWA 6009Australia

Novelty pervades the *** some cases,potentially irreversible abiotic and/or biotic changes have led to the crossing of thresholds and thus the formation of“novel ecosystems.”Their widespread emergence(particularly on land)and the presence of continued environmental change challenge a traditional restoration goal of restoring an historical ***,we argue that restoration could broaden its frame of reference to consider how novel ecosystems might be used to maintain global biodiversity and provide ecosystem services and,in doing so,save potentially wasted efforts in attempting to fulfil traditional *** we explore this contention in more depth by addressing:Are novel ecosystems innovative planning or lowering the bar?We show that novel ecosystems were not innovative planning in their original *** the contrary,they were recognized as ecosystems that were recalcitrant to traditional restoration approaches,coupled with an awareness that they had arisen inadvertently through deliberate human activity,either on-or *** recalcitrance to traditional restoration suggests that alternative goals may exist for these ecosystems using sometimes innovative *** management may include biodiversity conservation or restoration for ecological *** elucidate the latter aspect with reference to an experiment in the wheatbelt of Western Australia—The Ridgefield Multiple Ecosystem Services Experiment—the design of which has been informed by ecological theory and the acceptance of novelty as an ecosystem *** novel ecosystems do provide opportunities to broaden restoration planning and practice,and ultimately maintain and conserve global biodiversity in this era of environmental change,they necessarily“lower the bar”in restoration if the bar is considered to be the historical ***,in these times of flux,such a bar is increasingly ***,careful and appropriate interventions are required

关键词： No-analogue ecosystem Biodiversity conservation Ecosystem function Ecological restoration Restoration baseline Ridgefield multiple ecosystem services experiment York gum woodland

Correlation between plasmid DNA damage induced by pM_(10) and trace metals in inhalable particulate matters in Beijing air

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Earth Sciences 2006年第12期49卷 1323-1331页

作者： T. p. Jones L. Merolla R. J. richard Department of Earth Ocean and Planetary Sciences Cardiff UniversityCardiff CF10 3YE UK School of Biosciences Cardiff University PO Box 911 Cardiff CF10 3US UK

Based on the study of Beijing pM10 bioreactivity with the newly developed plasmid DNA assay method, and analysis for trace elements of pM10, the cause of plasmid DNA damage by pM10 was investigated. The study showed that plasmid DNA oxidative damages by pM10 are of difference in different seasons at various areas. The concentrations of TM50 of pM10 in whole samples respectively collected at urban and comparison sites during winter were 900 μg mL?1 and 74 μg mL?1, while those in their corresponding soluble fractions were 540 μg mL?1 and 86 μg mL?1. In contrast, TM50 contents of pM10 from summer whole samples at urban areas and comparison sites were 116 μg mL?1 and 210 μg mL?1, whereas those in their soluble fractions were 180 μg mL?1 and 306 μg mL?1. The difference of bioreactivity of Beijing pM10 resulted from the variation of trace elements. The oxidative damage of plasmid DNA caused by pb, Zn, As in pM10 (whole sample) was relatively strong. TM50 and Mn, V, Zn display stronger correlation in the soluble fraction. It implies that Zn could be the major trace element in Beijing pM10 which contributes to oxidative damage to plasmid DNA.

关键词： Beijing pM10 trace metals correlation health effect.

Worldwide practice in gastric cancer surgery

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2016年第15期22卷 4041-4048页

作者： Hylke JF Brenkman Leonie Haverkamp Jelle p Ruurda richard van Hillegersberg Department of Surgery University Medical Center Utrecht

AIM: To evaluate the current status of gastric cancer surgery ***: An international cross-sectional survey on gastric cancer surgery was performed amongst international upper gastro-intestinal surgeons. All surgical members of the International Gastric Cancer Association were invited by e-mail to participate. An English web-based survey had to be filled in with regard to their surgical preferences. Questions asked included hospital volume, the use of neoadjuvant treatment, preferred surgical approach, extent of the lymphadenectomy and preferred anastomotic technique. The invitations were sent in September 2013 and the survey was closed in January ***: The corresponding specific response rate was 227/615(37%). The majority of respondents: originated from Asia( 5 4 %), performed > 2 1 gastrectomies per year(79%) and used neoadjuvant chemotherapy(73%). An open surgical procedure was performed by the majority of surgeons for distal gastrectomy for advanced cancer(91%) and total gastrectomy for both early and advanced cancer(52% and 94%). A minimally invasive procedure was preferred for distal gastrectomy for early cancer(65%). In Asia surgeons preferred a minimally invasive procedure for total gastrectomy for early cancer also(63%). A D1+ lymphadenectomy was preferred in early gastric cancer(52% for distal, 54% for total gastrectomy) and a D 2 lymphadenectomy was preferred in advanced gastric cancer(93% for distal, 92% for total gastrectomy) CONCLUSION: Surgical preferences for gastric cancer surgery vary between surgeons worldwide. Although the majority of surgeons use neoadjuvant chemotherapy, minimally invasive techniques are still not widely adapted.

关键词： Gastric cancer Gastrectomy Laparoscopy neoplasm minimally invasive surgery

Stopover behavior of Red-eyed Vireos(Vireo olivaceus) during fall migration on the coast of the Yucatan peninsula

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Avian Research 2021年第4期12卷 491-502页

作者： richard Evan Feldman Antonio Celis-Murillo Jill L.Deppe Michael p.Ward Centro de Investigación Científica de Yucatán Unidad de Recursos NaturalesMeridaYucatánMexico prairie Research Institute Illinois Natural History SurveyUniversity of IllinoisUrbana-ChampaignIllinoisUSA U.S.Geological Survey Eastern Ecological Science CenterPatuxent Research RefugeLaurelMDUSA National Audubon Society WashingtonDCUSA Department of Natural Resources and Environmental Sciences University of IllinoisUrbana-ChampaignIllinoisUSA.

Background: For migrating birds, stopover requires spending time and energy that otherwise could be allocated to flying. Thus, birds optimally refuel their subsequent migratory flight by reducing stopover duration or foraging activ-ity in food-rich environments. In coastal habitats, birds may forego refueling and take short stopovers irrespective of local food availability. Given the paucity of studies exploring how migrants adjust stopover behavior in response to temporal variation in food availability, especially in the Neotropics, we fixed radio tags to 51 Red-eyed Vireos(Vireo olivaceous) over two years at two sites on the coast of Mexico's Yucatan ***: We applied VHF radio tags during the fall of 2016 and 2017, and tracked birds using automatic and manual receiving units. We estimated stopover duration and activity levels(one site only) for between six and fifteen birds,depending on site and year. We measured fruit availability weekly along the net lanes where we captured birds. We used a generalized linear model to estimate the relationships between stopover duration/activity level and fruit den-sity, bird body mass and year. We interpreted relationships for the model with the lowest AICc ***: We found that approximately half of the birds departed on the same day they were captured. For the birds that stayed longer, we could not discern whether they did so because they were light, or fruit density was high. On the other hand, lighter birds were more active than heavier birds but only in one of the two ***: Given our results, it is unlikely that Red-eyed Vireos refuel along the Yucatan coast. However, they still likely need to recuperate from crossing the Gulf of Mexico, which may necessitate foraging more often if in poor body condition. If the birds then move inland then stopover should be thought of as a large-scale phenomenon, where habitats with different functions may be spread out over a broad landscape.

关键词： Coastal dune Fruit Geographic barrier Gulf of Mexico phenology Stopover Time?minimization

Wildfire severity alters soil microbial exoenzyme production and fungal abundances in the southern Appalachian Mountains

在线全文

学校读者我要写书评

暂无评论

pedosphere 2024年第5期34卷 865-878页

作者： Megan L.SCHILL richard BAIRD Shawn p.BROWN Allison M.VEACH Department of Integrative Biology University of Texas at San AntonioSan Antonio TX 78249USA Biochemistry Molecular BiologyEntomology and Plant Pathology DepartmentMississippi State UniversityStarkville MS 39762USA Department of Biological Sciences The University of MemphisMemphis TN 38152USAAntonioand the University of Memphis。

Climate change has increased drought frequency and duration that are exacerbated by increased temperatures *** effect has,and will continue,to increase fire occurrence across many regions of North *** the southern Appalachian Mountains,wildfires with high burn severity occurred in 2016due to increased drought and human *** investigate the effects of burn severity on soil physicochemical properties,microbial extracellular enzyme production,and microbial abundances in a temperate region,surface soils(0-15 cm)were collected from two sites(the Great Smoky Mountains National park in Tennessee and the Nantahala National Forest in North Carolina,USA)spanning lightly,moderately,and severely burned areas,accompanied by adjacent unburned locations that act as *** soil samples were collected at three time points between 2017 and 2019(i.e.,0.5,1,and 2.5 years post-fire)among burn severity *** hydrolytic enzyme production varied over time,with severe burn plots having significantly lower enzyme production at 2.5years *** enzymes varied among burn severities and across time *** burn plots showed greater carbon-specific(β-glucosidase andβ-xylosidase)and phosphorus-specific(acid phosphatase)enzyme activities at 0.5 years post-fire,but this effect was *** 2.5 years post-fire,theβ-xylosidase and acid phosphatase activities were lower in severe or moderate burn plots relative to the *** contrast,the activity of nitrogen-specific enzyme leucyl aminopeptidase was the lowest in severe burn plots at 0.5 years post-fire,but was the lowest in light burn plots at 2.5 years *** fungi:bacteria ratio declined with burn severity,indicating that fungi are sensitive or less resilient to high burn severity during *** results suggest that wildfires alter trajectories for soil microbial structure and function within a 2.5-year timeframe,which potentially has long-term impacts on biogeochemical

关键词： burn severity extracellular enzyme fungi:bacteria ratio internal transcribed spacer microbial structure 16S rRNA

Exploring the Dynamic X-ray Universe:Scientific Opportunities for the Einstein probe Mission

在线全文

学校读者我要写书评

暂无评论

空间科学学报 2016年第2期36卷 117-138页

作者： YUAN Weimin OSBORNE Julian p ZHANG Chen WILLINGALE richard Key Laboratory for Space Astronomy and Technology National Astronomical ObservatoriesChinese Academy of Sciences School of Astronomy and Space Science University of Chinese Academy of Sciences Department of physics and Astronomy University of Leicester University

Time-domain astrophysics will enter a golden era towards the end of this decade with the advent of major facilities across the electromagnetic spectrum and in the multi-messenger realms of gravitational wave and *** the soft X-ray regime,the novel micro-pore lobster-eye optics provides a promising technology to realise,for the first time,focusing X-ray optics for wide-angle monitors to achieve a good combination of sensitivity and wide field of *** this context Einstein probe,a soft X-ray all-sky monitor mission,was proposed and selected as a candidate mission of priority in the space science programme of the Chinese Academy of *** paper reviews the most important science developments and key questions in this field towards 2020 and beyond,and how to achieve them *** also introduces the Einstein probe mission,including its key science goals and mission definition,as well as some of the key technological issues.

关键词： Time-domain astronomy High-energy astrophysics X-rays Transients Instruments