检索结果-南通市图书馆

Synthesis and Molecular Structure of A Bimetallic Salen Complex Containing Zn and La: A Disordered Nitrate Group Dancing between Two Metal Centers

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2005年第3期23卷 257-261页

作者： Leon Dyers jr Donald Van Derveer Xiu R Bu Department of Chemistry NASA Center for High Performance Polymers and Composites Clark Atlanta University Atlanta Georgia 30314 USADepartment of Chemistry Clemson University Clemson South Carolina 29634 USADepartment of Chemistry NASA Center for High Performance Polymers and Composites Clark Atlanta University Atlanta Georgia 30314 USA

A new bimetallic complex containing Zn and La was prepared from a salen ligand possessing methoxyl groups at the 3, 3′-positions. The structural feature is that one of nitrate groups is disordered and displaced between two metal centers. Crystal system: Triclinic space group:P-1, Z=2. a=0.82714(17) nm, b=1.3484(3) (1) nm, and c=1 3898(3) (1) nm, α=79.89(3)°, β=76.67(3)°, and γ=72.43(3)°. V=1 428 6(5) nm3, Dx=1.812 g·cm-3. (Δρ)max=1 510×10-3 enm3, (Δρ)min=-1.503×10-3 enm3. Accordingly, two water molecules occupy the metal centers in the apical positions via the syn-geometry.

关键词： bimetallic complex zinc lanthannm rare earths

Can a multistage approach improve individual tree mortality predictions across the complex mixed-species and managed forests of eastern North America?

在线全文

学校读者我要写书评

暂无评论

Forest Ecosystems 2023年第1期10卷 21-30页

作者： Cen Chen John Kershaw jr Aaron Weiskittel Elizabeth McGarrigle Center for Research on Sustainable Forests University of MaineOronoME04469USA Faculty of Forestry&Environmental Management University of New BrunswickFrederictonNBE3B 5A3Canada Nova Scotia Department of Natural Resources HalifaxNSB3J 3M8Canada

Tree mortality plays a fundamental role in the dynamics of forest ecosystems,yet it is one of the most difficult phenomena to accurately *** modeling strategies have been developed to improve individual tree mortality *** less explored strategy is the use of a multistage modeling *** improvements from this approach have remained largely *** this study,we developed a novel multistage approach and compared its performance in individual tree mortality predictions with a more conventional approach using an identical individual tree mortality model *** permanent plot data(n=9442)covering the Acadian Region of North America and over multiple decades(1965–2014)were used in this *** results indicated that the model behavior with the multistage approach better depicted the observed mortality and showed a notable improvement over the conventional *** difference between the observed and predicted numbers of dead trees using the multistage approach was much smaller when compared with the conventional *** addition,tree survival probabilities predicted by the multistage approach generally were not significantly different from the observations,whereas the conventional approach consistently underestimated mortality across species and overestimated tree survival probabilities over the large range of DBH in the *** new multistage approach also predictions of zero mortality in individual plots,a result not possible in conventional ***,the new approach was more tolerant of modeling errors because it based estimates on ranked tree mortality rather than error-prone predicted ***,this new multistage approach deserves to be considered and tested in future studies.

关键词： Tree mortality modeling Mortality disaggregation Mixed effect model Annualization Mixed forests

Alternative expressions for stand diameter in complex forests

在线全文

学校读者我要写书评

暂无评论

Forest Ecosystems 2023年第3期10卷 328-336页

作者： Mark J.Ducey John A.Kershaw jr. Department of Natural Resources and the Environment University of New HampshireDurhamNHUSA Faculty of Forestry and Environmental Management University of New BrunswickFrederictonNBCanada

Quadratic mean diameter is the most frequently reported descriptor of the diameter distribution of *** such,it is often used as an indicator of forest stand structure,developmental stage,and ecological and economic ***,quadratic mean diameter can be heavily influenced by the presence or absence of large numbers of small stems in lower canopy strata,and it is also sensitive to left-truncation of the diameter distribution,making its interpretation across inventories with different protocols ***,we examine three alternative expressions of stand diameter:the arithmetic and quadratic mean diameter of the thickest 100 trees per hectare,and the basal area-weighted mean *** data from the United States Forest Inventory and Analysis program for New York and New England,these alternative expressions showed closer correlation with multiple stand structural variables than did quadratic mean diameter,including merchantable cubic and board foot volume per hectare,aboveground live tree carbon per hectare,and total number of live and dead standing trees greater than 40 cm diameter at breast height per hectare(previously proposed as an index of old-growth structure).Arithmetic and quadratic mean diameter of the thickest 100 trees per hectare showed nearly identical performance,and the strongest correlations across the *** develop closed-form expressions for these variables when the diameter distribution is a Weibull,and illustrate their behavior relative to quadratic mean diameter for that *** the reasons for prevalence of quadratic mean diameter as an indicator remain valid,we suggest that these alternative measures should be more widely reported and analyzed to give a more informative depiction of stand structure and development in complex forests.

关键词： Forest structure Diameter at breast height Weibull distribution

Climate pledges versus commitment: Are policy actions of Middle-East and North African countries consistent with their emissions targets?

在线全文

学校读者我要写书评

暂无评论

Advances in Climate Change Research 2022年第4期13卷 612-621页

作者： Hermas ABUDU Presley K.WESSEH jr Boqiang LIN School of Management China Institute for Studies in Energy PolicyCollaborative Innovation Center for Energy Economics and Energy PolicyXiamen UniversityFujian361005China Belt and Road Research Institute Xiamen UniversityFujian361005China

Carbon emission is inevitable,and changes with energy consumption and economic development,presents policy options toward sustainable development ***,there is little assurance from policymakers in committing to climate change pledges:taking the Middle-East and North African(MENA)region as a specific case with using 2019 as a cut-off *** conducted an interim assessment of the Paris Agreement to ascertain whether climate actions are in tandem with emissions reduction *** use of difference-in-difference technique as a quasiexperiment supported by fixed-effects and placebo treatment models,the results point to evidence of less than 1%effective CO_(2) emissions reduction as of 2019 compared to the 2015 *** current carbon emissions reduction commitment level is far-reaching contrary to the Nationally Determined Contributions(NDCs)pledged(16.43%on average by 2030 compared to the 2015 level).The analysis suggests that achieving NDCs commitments are currently major burden on policymakers since the economic development is highly linked with nonrenewable energy ***,a more comprehensive framework when accounting for all available renewable and clean energy projects shows reduction levels in the range of 30%-40%from 2020 to *** results suggest that the Paris Agreement in MENA countries may be more effective from 2020,thus underscore the importance of capturing ongoing projects(involving renewable and clean energy technologies)into interim policy *** shared implication is that greater efforts are demanded from the region and at country levels to further decrease emissions through the use of negative emissions technologies particularly in the electricity generation sector.

关键词： Paris Agreement Carbon emissions reduction potential Carbon effciency:Climate change policy quasi-experiment MENA climate change performance

Symptomatic male with subclinical varicocele found on ultrasound evaluation

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

Asian Journal of Andrology 2016年第2期18卷 313-314页

作者： Ahmad Majzoub Edmund Sabanegh jr. Department of Urology Glickman Urological and Kidney Institute Cleveland Clinic Foundation CLeveland Ohio USA.

Scrotal pain is a commonly encountered complaint in urology practice. It occurs in around 2%-10% of patients with *** a relatively common association, the effect ofvaricocele on pain is much less investigated than its relation with infertility. Biggers and Soderdahl were the first to explore surgical treatment for pain attributed to a clinical varicocele in 1981, reporting an improvement rate of 48% after surgery.

关键词： @@

Liver-inclusive intestinal transplantation results in decreased alloimmune-mediated rejection but increased infection

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

Gastroenterology Report 2018年第1期6卷 29-37,I0001,I0002页

作者： Guosheng Wu Ruy J.Cruz jr Department of Gastrointestinal Surgery Xijing Hospital of Digestive DiseasesThe Fourth Military Medical UniversityXi’anShannxiChina Thomas E.Starzl Transplantation Institute University of Pittsburgh Medical CenterPittsburghPAUSA

Background and aims:A co-transplanted liver allograft has been thought to protect other organs from rejection-mediated injury;however,detailed analyses of co-transplanted liver on intestinal allograft outcomes have not been conducted to *** aimof the study was to compare immune-mediated injury,causes of graft failure and clinical outcomes between recipients who underwent either a liver-inclusive intestinal transplant(LITx)or liver-exclusive intestinal transplant(LETx).Methods:Between May 2000 and May 2010,212 adult patients undergoing LITx(n¼76)and LETx(n¼136)were *** underwent either liver combined intestinal or full multivisceral *** underwent either isolated intestinal or modified multivisceral ***:During 44.9631.4 months of follow-up,death-censored intestinal graft survival was significantly higher for LITx than LETx(96.9%,93.2%and 89.9%vs 91.4%,69.3%and 60.0%at 1,3 and 5 years;p¼0.0001).Incidence of graft loss due to rejection was higher in LETx than in LITx(30.9%vs 6.6%;p<0.0001),while infection was the leading cause of graft loss due to patient death in LITx(25.0%vs 5.1%;p<0.0001).Despite similar immunosuppression,the average number(0.87 vs 1.42,p¼0.02)and severity of acute cellular rejection episode(severe grade:7.9%vs 21.3%;p¼0.01)were lower in LITx than in *** of acute antibody-mediated rejection was also significantly lower in LITx than in LETx(3.6%vs 15.2%;p¼0.03).Incidence of chronic rejection was reduced in LITx(3.9%vs 24.3%;p¼0.0002).Conclusions:Intestinal allografts with a liver component appear to decrease risk of rejection but increase risk of *** findings emphasize that LITx has characteristic immunologic and clinical *** immunosuppression may need to be considered for patients who undergo LITx to attenuate increased risk of infection.

关键词： Intestinal transplant immunosuppression rejection infection

Dioxygen Affinity and Catalytic Performance of Bis-(furaldehyde) Schiff Bases Co(II) Complexes in Cyclohexene Oxidation

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

Chinese Chemical Letters 2001年第11期12卷 1043-1046页

作者： Sun, B Chen, jr Hu, JY Li, XJ Sichuan Univ Dept Chem Chengdu 610064 Peoples R China

Oxygenation constants and thermodynamic parameters DeltaH degrees and DeltaS degrees of cobalt (II) complexes with bis-(furaldehyde) Schiff bases (1, 2, 3, 4)were obtained by mearsuring saturated dioxygen uptake of these complexes in pyridine at different temperature. These complexes could activate molecular oxygen and were used as catalysts in cyclohexene oxidation. The influence of ligand structure on the dioxygen affinity and catalytic activity of the complexes were discussed.

关键词： Schiff base cobalt (II) complex oxygenation catalytic oxidation cyclohexene

Is gastric cancer after bariatric surgery on the rise?Will history repeat itself?

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Cancer Research 2023年第1期35卷 11-14页

作者： Adriana Vaz Safatle-Ribeiro Ulysses Ribeiro jr Department of Gastroenterology Instituto do Cancer do Estado de Sao PauloHospital das ClinicasFaculdade de MedicinaUniversidade de Sao Paulo(ICESP-HCFMUSP)Sao PauloSP 01246-000Brazil

Gastric cancer is the fifth most common cancer and the fourth leading cause of cancer-related death worldwide(1).Despite its decreasing incidence during the last decades,a major concern has been raised in patients submitted to bariatric surgery(2).Morbid obesity incidence has increased worldwide leading to low quality of life expectancy in children。

关键词： surgery Gastric death

Local perceptions of climate change and adaptation needs in the Ifugao Rice Terraces (Northern Philippines)

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2017年第8期14卷 1455-1472页

作者： Mario A.SORIANO jr. Johanna DIWA Srikantha HERATH Institute for the Advanced Study of Sustainability United Nations University School of Forestry and Environmental Studies Yale University

The Ifugao Rice Terraces in the Philippines is recognized worldwide as a sustainable landscape where humans live in harmony with nature. The success of the Ifugao Rice Terraces largely depends on the attunement of local farmers to their environment and their ability to adapt to perceived changes, as manifested in their complex body of traditional ecological and climatic knowledge. This paper examines the local perceptions on climate change and other challenges to sustainability through focus group discussions with farmers and traditional knowledge holders. Our main findings can be summarized as follows:(i) Ifugao farmers were able to observe climatic changes in recent years, and these changes were intimately linked with broader environmental and socio-cultural changes in the Ifugao social-ecological system;(ii) The climatic changes qualitatively observed by the farmers were in agreement with trends in datasets commonly used in scientific assessments, although this agreement depends on the spatial and temporal resolution of the dataset, and the type of statistical analysis performed, and;(iii) The Ifugaos stressed the importance of traditional knowledge and culture in climate change adaptation, and preferred measures which could increase internal adaptive capacity while addressingbroader sources of community vulnerability. Our results support calls to recognize Indigenous and Western science as equally valid ways of knowing. Discussions with the farmers revealed that in the Ifugao context, climate change may be better framed in the context of multiple stressors on rural livelihoods, with adaptation integrated into broader development objectives. Our findings also emphasize the need for greater engagement of indigenous Ifugao people in planning processes in order to identify adaptation strategies that are culturally appropriate, equitable, and effective in responding to local needs.

关键词： Ifugao Rice Terraces Climate Change Traditional Knowledge Indigenous Adaptation Social-Ecological System Sustainability