6,249 research outputs found
Mapping functional traits: comparing abundance and presence-absence estimates at large spatial scales
Efforts to quantify the composition of biological communities increasingly focus on functional traits. The composition of communities in terms of traits can be summarized in several ways. Ecologists are beginning to map the geographic distribution of trait-based metrics from various sources of data, but the maps have not been tested against independent data. Using data for birds of the Western Hemisphere, we test for the first time the most commonly used method for mapping community trait composition â overlaying range maps, which assumes that the local abundance of a given species is unrelated to the traits in question â and three new methods that as well as the range maps include varying degrees of information about interspecific and geographic variation in abundance. For each method, and for four traits (body mass, generation length, migratory behaviour, diet) we calculated community-weighted mean of trait values, functional richness and functional divergence. The maps based on species ranges and limited abundance data were compared with independent data on community species composition from the American Christmas Bird Count (CBC) scheme coupled with data on traits. The correspondence with observed community composition at the CBC sites was mostly positive (62/73 correlations) but varied widely depending on the metric of community composition and method used (R2: 5.6Ă10â7 to 0.82, with a median of 0.12). Importantly, the commonly-used range-overlap method resulted in the best fit (21/22 correlations positive; R2: 0.004 to 0.8, with a median of 0.33). Given the paucity of data on the local abundance of species, overlaying range maps appears to be the best available method for estimating patterns of community composition, but the poor fit for some metrics suggests that local abundance data are urgently needed to allow more accurate estimates of the composition of communities
Toward More Efficient Organic Solar Cells: A Detailed Study of Loss Pathway and Its Impact on Overall Device Performance in LowâOffset Organic Solar Cells
Low-offset organic solar cell systems have attracted great interest since nonfullerene acceptors came into the picture. While numerous studies have focused on the charge generation process in these low-offset systems, only a few studies have focused on the details of each loss channel in the charge generation process and their impact on the overall device performance. Here, several nonfullerene acceptors are blended with the same polymer donor to form a series of low-offset organic solar cell systems where significant variation in device performance is observed. Through detailed analyses of loss pathways, it is found that: i) the donor:acceptor interfaces of PM6:Y6 and PM6:TPT10 are close to the optimum energetic condition, ii) energetics at the donor:acceptor interface are the most important factor to the overall device performance, iii) exciton dissociation yield can be field-dependent owing to the sufficiently small energetic offset at the donor:acceptor interface, and iv) the change in substituents in the terminal group of Y-series acceptors in this work mainly affects energetics at the donor:acceptor interface instead of the interface density in the active layer. In general, this work presents a path toward more efficient organic solar cells
International Market Segmentation across Consumption and Communication Categories: Identity, Demographics, and Consumer Decisions and Online Habits
In this chapter we will discuss the different approaches to market segmentation and selection and explore how the selection process influences the companyâs culture, its brand positioning, and how it is impacted upon by the overall marketing and communication strategy and vice versa. Some questions this chapter considers and discusses are: Which segments should firmsâ international marketing activities (including financial, human resources, and the firmâs capabilities) focus on? How do multinationals decide if segmentation efforts are effective? Finally, we will explore how organizations1 can monitor and control the various activities and outcomes, in order to ensure sustainable competitive advantage(s) in a highly competitive marketplace and online marketspace
The Use of Palliative Performance Score in Patients with End-Stage Liver Disease
â Palliative Care services are often underutilized in patients with End-Stage Liver Disease (ESLD) and often only initiated at the end of life
â The Palliative Performance Score (PPS) is an important tool used in Palliative Care to assess functional status
â PPS has five functional dimensions: ambulation, activity level and evidence of disease, self-care, oral intake, and level of consciousness
â The aim of this study is to determine if there is a correlation between Model for End-Stage Liver Disease (MELD) score and PPS in ESLD patients
â MELD is used to predict mortality and to prioritize liver transplant allocation in ESLD patientshttps://jdc.jefferson.edu/medposters/1011/thumbnail.jp
The peculiar B-type supergiant HD327083
Coude spectroscopic data of a poorly-studied peculiar supergiant, HD327083,
are presented. Halpha and Hbeta line profiles have been fitted employing a
non-LTE code adequate for spherically expanding atmospheres. Line fits lead to
estimates of physical parameters. These parameters suggest that HD327083 may be
close to the Luminous Blue Variable phase but it is also possible that it could
be a B[e] Supergiant.Comment: 4 pages, 4 figures, Accepted for publication in A&A Lette
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Validity of the National Death Index to ascertain the date and cause of death in men having undergone prostatectomy for prostate cancer.
BackgroundThe National Death Index (NDI) is a centralized database containing information from death certificates that are frequently referenced by health and medical investigators to ascertain vital statistics. Yet, it commonly includes misclassified causes of death. Since the NDI is frequently relied upon in studies that evaluate outcomes following radical prostatectomy (RP) for prostate cancer (PC), we evaluated its validity by referencing mortality data from the Shared Equal Access Regional Cancer Hospital (SEARCH) database which is a prospectively managed database of 5009 Veterans who underwent a RP at eight Veterans Affairs medical centers between 1982 and 2016.MethodsWe compared vital status, cause of death and date of death from the SEARCH database with the NDI.ResultsA total of 1312 men in SEARCH were deceased, yet the NDI reported 17% (219) of those men as still alive. Among the 1093 men who had concordant vital status in both SEARCH and NDI, the date of death was an exact match within one day, a week, or 31 days in 94%, 97%, 99%, and 100%, respectively. Of those men coded as dying from prostate cancer in the SEARCH database (nâ=â105), 12% were coded as having died from non-PC causes in the NDI. Meanwhile, among patients coded by the NDI as having died of PC (nâ=â139), 34% were coded in SEARCH as having died of non-PC causes.ConclusionsThese findings demonstrate that the NDI provides accurate dates of death, but frequently misclassifies whether a death was due to prostate cancer. Studies that rely upon death certificates, as captured in the NDI, may be unreliable to report prostate cancer-specific mortality rates after prostatectomy
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