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Late Ordovician Mass Extinction: Earth, fire and ice

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National Science Review 2024年第1期11卷 51-65页

作者： david A.t.Harper Palaeoecosystems Group Department of Earth SciencesDurham University

the Late Ordovician Mass Extinction was the earliest of the ‘big' five extinction events and the earliest to affect the trajectory of metazoan life. two phases have been identified near the start of the Hirnantian period and in the middle. It was a massive taxonomic extinction, a weak phylogenetic extinction and a relatively benign ecological extinction. A rapid cooling, triggering a major ice age that reduced the temperature of surface waters, prompted a drop in sea level of some 100 m and introduced toxic bottom waters onto the shelves. these symptoms of more fundamental planetary processes have been associated with a range of factors with an underlying driver identified as volcanicity. Volcanic eruptions, and other products, may have extended back in time to at least the Sandbian and early Katian, suggesting the extinctions were more protracted and influential than hitherto documented.

关键词： Ordovician LOME paleoecology palaeobiogeography biotas

Combining innovative science and policy to improve air quality in cities with refining and chemicals manufacturing： the case study of Houston, texas, USA

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Frontiers of Chemical Science and Engineering 2017年第3期11卷 293-304页

作者： david t. Allen University of texas Austin Department of Chemical Engineering and Center for Energy and Environmental Resources Austin TX 78759 USA

In Houston, a combination of urban emissions from a city of 4 million people, coupled with emissions from extensive petroleum refining and chemical manufacturing, leads to conditions for photochemistry that are unique in the United States, and historically, the city had experienced some of the highest ozone concentrations recorded in the United States. Large air quality field studies （the texas Air Quality Studies or texAQS I and II） were conducted to determine root causes of the high ozone concentrations. Hundreds of air quality investigators, from around the world, deployed instruments on aircraft, on ships, and at fixed ground sites to make extensive air quality measurements; detailed photochemical modeling was used to interpret and assess the implications of the measurements. the texas Air Quality Studies revealed that both continuous and episodic emissions of light alkenes, which came to be called highly reactive volatile organic compounds, played a critical role in the formation of ozone and other photochemical oxidants in the region. Under- standing and quantifying the role of these emissions in regional air quality required innovations in characterizing emissions and in photochemical modeling. Reducing emissions required innovative policy approaches. these coupled scientific and policy innovations are described, and the result, substantially cleaner air for Houston, is documented. the lessons learned from the Houston air quality experience are relevant to cities with similar population and industrial profiles around the world.

关键词： ozone air quality highly reactive volatile organic compounds Houston

Pathologic response to preoperative transarte- rial chemoembolization for resectable hepatocellular carcinoma may not predict recurrence after liver resection

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Hepatobiliary & Pancreatic Diseases International 2016年第2期15卷 122-124页

作者： Kwang Yeol paik Eung Kook Kim Department of Surgery Yeouido St.Mary’s Hospital The Catholic University of Korea College of Medicine

Hepatocellular carcinoma （HCC） is one of the most frequent complications in patients with .liver cirrhosis. HCC without cirrhosis is rareand obviously a different entity. treatment depends on tumor stage, liver function and general performance. Results of locoregional treatment, resection or liver transplantation are superior to those of medical therapy. Surgical approaches are potentially curative. Underlying cirrhosis is usually the limiting factor for the extent of resection and persists after resection. Liver transplantation eliminates both cirrhosis and, potentially, the tumor. Whereas surgery （functional liver capacity provided） may be performed even in advanced tumors, liver transplantation is advocated in less advanced （t2） tumors in order to keep the rate of recurrent tumor low. Responsible use of scarce grafts requires sticking to this rule.

关键词： recurrence cirrhosis preoperative frequent extrahepatic cirrhotic dissemination potentially metastases necrotic

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Influence of incubation temperature on sea turtle hatchling quality

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Integrative Zoology 2017年第5期12卷 352-360页

作者： david t.BOOtH School of Biological Sciences The University of QueenslandSt LuciaQueenslandAustralia

Since the 1980s it has been known that incubation temperature influences the sex ratio of sea turtle hatchlings emerging from their nests,and there has been much speculation on how global climate change might threaten sea turtle populations by raising nest temperatures and causing highly female-biased hatchling sex *** recently,studies have indicated that incubation temperature can also influence the size and locomotor performance of sea turtle *** I review recent studies that have explored the influence of incubation temperature on sea turtle hatchling quality in terms of hatchling morphology and locomotor performance.I also discuss the likely underlying mechanisms responsible for incubation temperature-induced differences in hatchling locomotor performance,and how an increase in nest temperature associated with global warming might affect recruitment of sea turtle hatchlings.

关键词： locomotor performance nest temperature phenotype sea turtle hatchling

Dielectric properties of amorphous Zr-Al-O and Zr-Si-O thin films

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Journal of Advanced Dielectrics 2015年第1期5卷 71-78页

作者： t.A.Naoi Hanjong paik M.L.Green R.B.van Dover Department of Materials Science and Engineering Cornell University IthacaNew York 14853USA National Institute of Standards and technology Gaithersburg Maryland 20899USA

We have systematically studied the composition dependence of the dielectric properties of Zr_(1-x)Al_(x)O_(2-x/2)and Zr_(1-x)Si_(x)O_(2).An essentially linear variation of the static dielectric constant,ε_(s),was observed as a function of composition,x,for compositions rich in the p-block element,i.e.,x>0.4,for both chemical *** an abrupt change inε_(s)is found near x≈0.35,associated with the onset of crystallinity in as-deposited *** fields do not show a comparable composition *** of the index of refraction at optical frequencies,combined with a simple Clausius-Mossotti interpretation,indicates that low-frequency(ionic)contributions to the polarizability exhibit systematic deviation with respect to values linearly interpolated from the *** trends are not consistently affected by the presence of crystalline order,but are related to changes associated with heterogeneous local oxygen coordination and bonding.

关键词： Permitivitty amorphous zirconia

Public Risk Perception Attitude and Information-Seeking Efficacy on Floods:A Formative Study for Disaster Preparation Campaigns and Policies

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International Journal of Disaster Risk Science 2020年第5期11卷 592-601页

作者： Do Kyun david Kim t.Phillip Madison Department of Communication University of Louisiana at LafayetteLafayette.LA 70503USA

Floods are among the most frequent and devastating natural hazards and disasters in many southern states in the United *** study examined the relationship and reciprocal predictability between two theoretical constructs-risk perception attitude(RPA)and informationseeking efficacy(ISE)——in regard to pluvial *** addition,this study extended these theoretical constructs to investigate differences in RPA and ISE among potential audience segments,providing practitioners with applicable insights for designing effective flood prevention and risk management *** of data from 716 residents in south Louisiana revealed a statistically strong relationship between RPA and *** research also identified specific audience segments that would benefit from an increase in RPA and ISE concerning *** meaningful findings infonn a discussion of the theoretical and practical implications of the relationship between RPA and ISE and guide future disaster preparation campaigns and policies.

关键词： Communication campaign Disaster preparation Flood victims Information-seeking efficacy Pluvial flood Risk perception attitude

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Biobanking and omics

Frontiers in Biology 2018年第4期13卷 287-292页

作者： david t. Harris Executive Director Biorepository University of Arizona PO Box 245221. AHSC 6122 Tucson AZ 85724 USA

BACKGROUND： the ＂Era of Big Data＂ and ＂Precision Medicine＂ is now upon us. that is, interrogation of large data sets obtained from groups of similar patients or from the patient themselves over time will now hypothetically permit therapies to be designed to provide maximal efficacy with minimal side effects. However, such discoveries depend upon recruitment of very large numbers of subjects （tens of thousands） along with their associated biospecimens and medical records. When considering the establishment of a biobank or the refocusing of an existing repository for the purpose of＂omics＂ research （i.e., genomics, metabolomics, proteomics, microbiomics, etc.） and/or precision medicine, there are a number of considerations to ponder. Each of these facets is discussed. OBJECtIVE： the objective of this review is to describe best practices for the establishment and operations ofa biobank that will be used for omics （genomics, proteomics, metabolomics, microbiomics） analyses based on published literature and our own practical experiences. MEtHODS： We describe the most commonly described approaches to a variety of biobanking issues, including our own practical experiences over the past 5 years. RESULtS： Based on the particular biobanking situation and downstream application, we have described best practices based on the literature and own experience, taking into consideration ease of application and costs. CONCLUSIONS： the banking of various types of clinical biospecimens has many valuable uses but often depends on overall costs versus sample utility. In addition, specimen flexibility is important but is influenced by the ease or difficulty of the application. It is always preferable to collect and stored a biospecimen in a format that allows for multiple types of downstream analyses, but that often requires additional expertise, equipment and reagents that can increase overall costs. We have described the methodologies most successfully applied to many situations.

关键词： biobanking genomics metabolomics microbiomics methodology precision medicine big data

Super-hydrophobic stearic acid layer formed on anodized high purified magnesium for improving corrosion resistance of bioabsorbable implants

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Journal of Magnesium and Alloys 2018年第4期6卷 327-336页

作者： Sohrab Khalifeh t.david Burleigh Materials&Metallurgical Engineering Department New Mexico Institute of Mining&TechnologySocorroNM 87123USA

Magnesium and its alloys are ideal candidates for bioabsorbable ***,they can dissolve too rapidly in the human body for most *** this research,high purified magnesium(HP-Mg)was coated with stearic acid(SA)to slow the corrosion rate of magnesium in simulated body fluid at 37±1°***-Mg was anodized(AC and DC voltages)to form an oxide/hydroxide layer,and then it was immersed in a SA *** SA coated layer surface,anodized layer,and the thickness of the oxide/hydroxide layer were investigated with Scanning Electron Microscopy(SEM).Electrochemical impedance spectroscopy(EIS)and potentiodynamic polarization(PDP)were used to estimate the corrosion rate of HP-Mg *** results confirm that the hydrophobic coating can decrease the corrosion rate of HP-Mg by more than *** protectiveness of coated layer for anodized specimens with AC voltage continue for 2 and 3 *** the HP-Mg coated anodized with DC voltage,the coated layer could improve the corrosion resistance for only a few days.

关键词： Magnesium Biomaterials Hydrophobic layer Stearic acid Simulated body fluid Electrochemical impedance spectroscopy

Quality measures of reconstruction filters for stereoscopic volume rendering

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Computational Visual Media 2016年第1期2卷 19-30页

作者： david A.t.Roberts Ioannis Ivrissimtzis School of Engineering and Computing Sciences Durham University

In direct volume rendering(DVR), the choice of reconstruction filter can have a significant effect on the visual appearance of the images produced and thus, on the perceived quality of a DVR rendered scene. this paper presents the results of a subjective experiment where participants stereoscopically viewed DVR rendered scenes and rated their subjective *** statistical analysis of the results focuses on the relationship between the quality of the stereoscopic scene and properties of the filters such as post-aliasing and smoothing, as well as the relationship between the quality of the stereoscopic scene and properties of the rendered images such as shape *** experiment evaluated five reconstruction filters on four different volumetric datasets. Participants rated the stereoscopic scenes on four quality measures:depth quality, depth layout, lack of jaggyness, and sharpness. the results show that the correlation between the quality measures and post-aliasing and smoothing, which are properties associated with each reconstruction filter, is moderate and statistically insignificant. On the other hand, the correlation between the quality measures and compactness, which is a property specific to each rendered image, is strong and statistically significant.

关键词： direct volume rendering(DVR) reconstruction filters stereoscopic user evaluations

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