检索结果-南通市图书馆

Morphodynamic signatures derived from daily surface elevation dynamics can explain the morphodynamic development of tidal flats

中国毒理学会第六届全国毒理学大会

作者： tom HUTCHINSON School of Biological Sciences University of PlymouthDrake CircusPlymouth PL4 8AAUnited Kingdom

＜正＞The historical approach to protecting human health and ecosystem quality from the adverse effects of chemicals is focused primarily on whole animal toxicity testing with individual chemicals of *** observed recently by the OECD（2013）,due to the costs and time involved it is neither practical nor feasible to comprehensively test all synthetic chemicals that could affect human health and ecosystem quality using this traditional *** eco-toxicology developed internationally since the 1960s primarily using a whole organism approach,combined with expertise in chemistry,ecology and microbiology in order to restore polluted ecosystems and prospectively undertake toxicity testing on individual chemicals using individual model *** example in European regulatory ecotoxicology, aquatic toxicity testing has often focused upon freshwater fish,crustaceans and algae and the combined results used to derive Predicted No Effect Concentrations（PNEC） for both freshwater and marine *** are then typically compared with Predicted Exposure Concentrations （PEC） and Measured Exposure Concentrations （MEC） in order to undertake an initial environmental risk assessment of the single chemicals of *** some cases refining the environmental risk assessment may require aquatic toxicity testing using a wider range of freshwater or marine species according to the pattern of use of the chemical of interest or in view of enhanced environmental exposure information（Hutchinson et al,2013）.Extrapolation from the model species included in the OECD Test Guidelines（eg chironomids, daphnids,zebrafish,etc） to the wider ecosystem of interest is recognised to pose a major scientific challenge.A notable example of the scientific weaknesses of this historical approach is the unexpected long-term reproductive impacts on fish and invertebrates of oestrogens and other endocrine disrupting chemicals often discharged into lakes,rivers and coastal *** the pas

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Water Science and Engineering 2023年第1期16卷 14-25页

作者： Tim J.Grandjean Jaco C.de Smit Jim van Belzen Gregory S.Fivash Jeroen van Dalen tom Ysebaert Tjeerd J.Bouma Department of Estuarine and Delta Systems Royal Netherlands Institute for Sea Research(NIOZ)4401 NT YersekeThe Netherlands Faculty of Geosciences Department of Physical GeographyUtrecht University3508 TC UtrechtThe Netherlands

Understanding the sensitivity of tidal flats to environmental changes is ***,most studies rely on process-based models to systematically explain the morphodynamic evolution of tidal *** this study,we proposed an alternative empirical approach to explore tidal flat dynamics using statistical indices based on long-term time series of daily surface elevation *** elevation dynamic(SED)indices focus on the magnitude and period of surface elevation changes,while morphodynamic signature(MDS)indices relate sediment dynamics to environmental *** statistical analyses were applied to an intervention site in the Netherlands to determine the effect of recently constructed groynes on the tidal *** these analyses,we were able to(1)detect a reduction in the daily SED and(2)determine that the changes in the daily SED were predominantly caused by the reduction in wave impact between the groynes rather than the reduction in tidal ***,the presented results showed that the combination of novel statistical indices provides new insights into the trajectories of tidal flats,ecosystem functioning,and sensitivity to physical drivers(wind and tides).Finally,we suggested how the SED and MDS indices may help to explore the future trajectories and climate resilience of intertidal habitats.

关键词： Surface elevation dynamics Tidal flat trajectories Morphodynamic development Morphodynamic signature Bed level dynamics

Dispersion of neutron spin resonance mode in Ba_(0.67)K_(0.33)Fe_(2)As_(2)

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 Physics B 2021年第12期30卷 1-6页

作者： Tao Xie Chang Liu tom Fennell Uwe Stuhr Shi-Liang Li Hui-Qian Luo Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100190China Laboratory for Neutron Scattering and Imaging Paul Scherrer InstitutCH-5232 Villigen PSISwitzerland Songshan Lake Materials Laboratory Dongguan 523808China

We report an inelastic neutron scattering investigation on the spin resonance mode in the optimally hole-doped ironbased superconductor Ba_(0.67)K_(0.33)Fe_(2)As_(2)with T_c=38.2 *** the resonance is nearly two-dimensional with peak energy ER≈14 meV,it splits into two incommensurate peaks along the longitudinal direction([H,0,0])and shows an upward dispersion persisting to 26 *** dispersion breaks through the limit of total superconducting gaps△_(tot)=|△k|+|△k+Q|(about 11-17 meV)on nested Fermi surfaces measured by high resolution angle resolved photoemission spectroscopy(ARPES).These results cannot be fully understood by the magnetic exciton scenario under s^(±)-pairing symmetry of superconductivity,and suggest that the spin resonance may not be restricted by the superconducting gaps in the multi-band systems.

关键词： iron-based superconductor neutron spin resonance magnetic excitations

Population Bursts of Parvalbumin-Positive Interneurons Inhibit Spiking Pyramidal Cells in Spontaneously Active Cortical in Vitro Networks

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Chemistry and Chemical Engineering 2012年第11期6卷 1033-1042页

作者： tom Reimer Werner Baumann Jan Gimsa Department of Biophysics University of Rostock Rostock 18057 Germany

Author present the interplay between different neuron types in the spontaneous electrical activity of low density cortical in vitro networks grown on MEA （multielectrode arrays） of glass neurochips. In 10% of the networks, the continuously spiking activity of some neurons was inhibited by synchronous bursts or superbursts of the majority of the other neurons. Immunohistochemical staining subsequent to MEA recordings suggest that the synchronously bursting neurons are parvalbumin-positive interneurons with abundant axonal ramifications. Blocking chemical synaptic transmission by Ca2＋-free medium revealed that the curbed spiking neurons are intrinsically active. It is assumed that these neurons are pyramidal cells which may be inhibited by groups of synchronously bursting interneurons. It is propose that the observed burst-induced inhibition is an important principle in the temporal organization of neuronal activity as well as in the restriction of excitation, and thus essential for information processing in the cerebral cortex.

关键词： Neurochip MEA cerebral cortex cortical networks spontaneous activity inhibitory interaction parvalbumin interneurons.

Methodological challenges of cross-language qualitative research with South Asian communities living in the UK

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Family Medicine and Community Health 2016年第2期4卷 16-28页

作者： Manbinder S.Sidhu Farina Kokab Kate Jolly tom Marshall Nicola K.Gale Paramjit Gill Institute of Applied Health Research University of BirminghamEdgbastonBirminghamB152TTUK Health Services Management Centre School of Social PolicyUniversity of BirminghamEdgbastonBirminghamB152TTUK

Objective:We investigate(1)the influence of ethnic,gender,and age concordance with inter-viewers and(2)how expression of qualitative data varies between interviews delivered in English and community languages(Punjabi/Urdu)with monolingual and bilingual participants across three generations of the Indian Sikh and Pakistani Muslim communities living in the ***:We analyzed and interpreted semi-structured interview transcripts that were designed to collect data about lifestyles,disease management,community practices/beliefs,and social ***,qualitative content analysis was applied to ***,a framework was ap-plied as a guide to identify cross-language illustrations where responses varied in length,expression and ***:Participant responses differed by language and ***-generation migrants when discussing religion,culture,or family practice were far likelier to use group or community narra-tives and give a longer response,indicating familiarity with or importance of such *** and gender concordance generated greater rapport between researchers and participants centered on community values and ***,open-ended questions that were less direct were better suited for first-generation ***:Community-based researchers need more time to complete interviews in second languages,need to acknowledge that narratives can be contextualized in both personal and com-munity views,and reframe questions that may lead to greater ***,we detail a number of recommendations with regard to validating the translation of interviews from commu-nity languages to English as well as measures for testing language proficiency.

关键词： Ethnicity community concordance language South Asian qualitative interviews

Antioxidant enriched enteral nutrition and oxidative stress after major gastrointestinal tract surgery

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2008年第45期14卷 6960-6969页

作者： Mireille FM van Stijn Gerdien C Ligthart-Melis Petra G Boelens Peter G Scheffer tom Teerlink Jos WR Twisk Alexander PJ Houdijk Paul AM van Leeuwen Department of Surgery VU University Medical Center Amsterdam Amsterdam and Medical Center Alkmaar Department of Surgery VU University Medical Center Amsterdam Department of Surgery Catharina Hospital Department of Clinical Chemistry VU University Medical Center Amsterdam Department of Epidemiology and Biostatistics VU University Medical Center Amsterdam Department of Surgery Medical Center Alkmaar

AIM: To investigate the effects of an enteral supple-ment containing antioxidants on circulating levels of antioxidants and indicators of oxidative stress after major gastrointestinal ***: Twenty-one patients undergoing major upper gastrointestinal tract surgery were randomised in a single centre, open label study on the effect of postoperative enteral nutrition supplementedwith antioxidants. The effect on circulating levels of antioxidants and indicators of oxidative stress, such as F2-isoprostane, was studied. RESULTS: The antioxidant enteral supplement showed no adverse effects and was well tolerated. After surgery a decrease in the circulating levels of antioxidant parameters was observed. Only selenium and glutamine levels were restored to pre-operative values one week after surgery. F2-isoprostane increased in the first three postoperative days only in the antioxidant supplemented group. Lipopolysaccharide binding protein (LBP) levels decreased faster in the antioxidant group after ***: Despite lower antioxidant levels there was no increase in the circulating markers of oxidative stress on the first day after major abdominal surgery. The rise in F2-isoprostane in patients receiving the antioxidant supplement may be related to the conversion of antioxidants to oxidants which raises questions on antioxidant supplementation. Module AOX restored the postoperative decrease in selenium levels. The rapid decrease in LBP levels in the antioxidant group suggests a possible protective effect on gut wall integrity. Further studies are needed on the role of oxidative stress on outcome and the use of antioxidants in patients undergoing major abdominal surgery.

关键词： Antioxidants Critical illness Enteral nutrition Oxidative stress Surgery Upper gastrointestinal tract

Spatial and Temporal Habitat Use by GPS Collared Male Cheetahs in Modified Bushland Habitat

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Forestry 2016年第4期6卷 269-280页

作者： Matti Nghikembua Jacob Harris tom Tregenza Laurie Marker Cheetah Conservation Fund Otjiwarongo Namibia University of Exeter Penryn Campus Cornwall United Kingdom

Cheetahs and other apex predators are threatened by human-wildlife conflict and habitat degradation. Bush encroachment creates one of the biggest forms of habitat change, thus it is important to understand the impact this has on habitat use. We investigated habitat preferences of five male cheetahs in Namibian farmlands degraded by bush encroachment. Cheetahs were tracked using satellite based Global System for Mobile (GSM) collars providing a higher resolution on ranging behavior. We aimed to investigate: 1) habitat characteristics;2) evidence for habitat selection;3) temporal activity partitioning;and 4) whether revisits to locations were related to habitat type. There were differences in habitat characteristics, showing that cheetahs were able to utilise different habitats. Fecal pellet counts revealed that warthog, oryx, scrub hare and kudu were most abundant. The cheetahs spent more time in high visibility shrubland, suggesting they selected rewarding patches within predominantly bush-encroached landscapes. The usage in marginal habitat was strikingly influenced by habitat type, with both previously cleared and open vegetated areas showing high proportions in edge use. Individuals exhibited significant temporal activity partitioning, showing peaks between late afternoon and early morning hours. This finding could be key to managing human-wildlife conflict by showing that increased protection such as the use of herders and livestock guarding dogs should be used as mitigation methods to minimize the impact of cheetah specific temporal patterns at all times as defined in this research. Visits to the same locations were not correlated to habitat type;revisits may be dictated by other reasons such as social interaction, prey density or avoidance of other predators. Findings from this study will help build existing knowledge on the effects bush encroachment has on cheetah habitat preference.

关键词： Bush Encroachment Cheetah Conservation Land Use Management

Melanotic Neuroectodermal Tumor of Infancy —A Rare Case of an Encapsulated Tumor

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Stomatology 2022年第4期12卷 130-136页

作者： tom Osundwa Mary Mungania Safari Paterne Nelson Oduor Department of Oral and Maxillofacial Surgery University of Nairobi Nairobi Kenya Kenyatta National and Referral Hospital Nairobi Kenya Gertrude’s Children’s Hospital Nairobi Kenya Department of Surgery University of Nairobi Nairobi Kenya

Melanotic neuroectodermal tumor of infancy (MNTI) is a rare benign, locally invasive neoplasm afflicting the infant more often in the craniofacial region. The current understanding is that this tumor’s origin is neural crest cells. The typical presentation is that a rapidly growing non-ulcerated anterior maxillary mass occurs in an infant usually less than six months old. This tumor may involve other areas including the ovaries, epididymis, femur, mandible, and brain. We present that an 8-month-old infant with a maxillary lesion of MNTI appeared encapsulated, which is a hitherto unreported feature. Investigations leading to the diagnosis and the management of the case are also presented. The need to report cases of this rare entity cannot be overemphasized as this will go a long way in adding new knowledge about its biological nature.

关键词： Melanotic Neuroectodermal Tumor Infancy

Endoscopic ultrasound-guided biliary drainage:Are we there yet?

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastrointestinal Endoscopy 2021年第8期13卷 302-318页

作者： Rishi Pawa Troy Pleasant Chloe tom Swati Pawa Department of Internal Medicine Section of Gastroenterology and HepatologyWake Forest Baptist Medical CenterWinston-SalemNC 27157United States Department of Medicine Wake Forest School of MedicineWinston-SalemNC 27101United States

Endoscopic retrograde cholangiopancreatography(ERCP)is the mainstay procedure of choice for management of obstructive biliary *** ERCP is widely performed with high success rates,the procedure is not feasible in every patient such as cases of non-accessible *** the setting of unsuccessful ERCP,endoscopic ultrasound-guided biliary drainage(EUS-BD)has become a promising alternative to surgical bypass and percutaneous biliary drainage(PTBD).A variety of different forms of EUS-BD have been described,allowing for both intrahepatic and extrahepatic *** studies have reported high success rates utilizing EUS-BD for both transpapillary and transluminal drainage,with fewer adverse events when compared to *** in novel technologies designed specifically for EUS-BD have led to increased success rates as well as improved safety profile for the *** techniques of EUS-BD are yet to be fully standardized and are currently performed by highly trained advanced *** aim of our review is to highlight the different EUSguided interventions for achieving biliary drainage and to both assess the progress that has been made in the field as well as consider what the future may hold.

关键词： Endoscopic ultrasound-guided biliary drainage Endoscopic ultrasound-guided rendezvous Endoscopic ultrasound-guided choledochoduodenostomy Endoscopic ultrasound-guided hepaticogastrostomy Endoscopic ultrasound-guided gallbladder drainage Endoscopic ultrasound-directed transgastric endoscopic retrograde cholangiopancreatography