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Beta diversity quantifies the spatial structuring of ecological communities and is a fundamental partition of biodiversity, central to understanding many macroecological phenomena in modern biology and paleobiology. Despite its common application in ecology, studies of beta diversity in the fossil record are relatively limited at regional spatial scales that are important for understanding macroevolutionary processes. The spatial scaling of beta diversity in the fossil record is poorly understood, but has significant implications due to temporal variation in the spatial distribution of fossil collections and the large spatiotemporal scales typically employed. Here we test the spatial scaling of several common measures of beta diversity using the Cenozoic shallow-marine molluscan fossil record of New Zealand and derive a spatially standardized time series of beta diversity. To measure spatial scaling, we use and compare grid-cell occupancy based on an equal-area grid and summed minimum spanning tree length, both based on reconstructed paleocoordinates of fossil collections. We find that beta diversity is spatially dependent at local to regional scales, regardless of the metric or spatial scaling utilized, and that spatial standardization significantly changes apparent temporal trends of beta diversity and, therefore, inferences about processes driving diversity change.
Quantifying true patterns of biodiversity change over the Cenozoic has major implications for all of biology and paleontology but is still a source of significant debate. The problem centers on the magnitude and nature of several well-known sampling effects and analytical biases in the fossil record, including the Pull of the Recent. We test the effect of the Pull of the Recent at both generic and species levels on the exemplary New Zealand Cenozoic marine mollusk fossil record. We examine several biological traits of species to determine whether particular attributes of taxa control their likely presence or absence in the youngest fossil record (<2.4 Ma). We demonstrate that, for a tectonically active region, the Pull of the Recent does not exert a strong effect on apparent diversity patterns of genera and species over the Cenozoic at temporal scales typically used in global and regional biodiversity analyses. This result agrees with previous studies quantifying the effect of the Pull of the Recent in the marine and terrestrial realms at the genus level. The effect of the Pull of the Recent, although small, is greatest for the youngest fossil record (<2.4 Ma), particularly for species. This increase cannot easily be explained by effects related to shell mineralogical composition, size, habitat, taxonomic class, or lithification. The small effect that the Pull of the Recent exerts on the New Zealand molluscan fossil record implies that the apparent rise in regional marine diversity during the Cenozoic represents a true biological signal and/or reflects other confounding effects not considered here.
It is not clear to what extent associations between schizophrenia, cannabis use and cigarette use are due to a shared genetic etiology. We, therefore, examined whether schizophrenia genetic risk associates with longitudinal patterns of cigarette and cannabis use in adolescence and mediating pathways for any association to inform potential reduction strategies.
Associations between schizophrenia polygenic scores and longitudinal latent classes of cigarette and cannabis use from ages 14 to 19 years were investigated in up to 3925 individuals in the Avon Longitudinal Study of Parents and Children. Mediation models were estimated to assess the potential mediating effects of a range of cognitive, emotional, and behavioral phenotypes.
The schizophrenia polygenic score, based on single nucleotide polymorphisms meeting a training-set p threshold of 0.05, was associated with late-onset cannabis use (OR = 1.23; 95% CI = 1.08,1.41), but not with cigarette or early-onset cannabis use classes. This association was not mediated through lower IQ, victimization, emotional difficulties, antisocial behavior, impulsivity, or poorer social relationships during childhood. Sensitivity analyses adjusting for genetic liability to cannabis or cigarette use, using polygenic scores excluding the CHRNA5-A3-B4 gene cluster, or basing scores on a 0.5 training-set p threshold, provided results consistent with our main analyses.
Our study provides evidence that genetic risk for schizophrenia is associated with patterns of cannabis use during adolescence. Investigation of pathways other than the cognitive, emotional, and behavioral phenotypes examined here is required to identify modifiable targets to reduce the public health burden of cannabis use in the population.
Remarkably few attempts have been made to estimate contemporary effective population size (Ne) for parasitic species, despite the valuable perspectives it can offer on the tempo and pace of parasite evolution as well as coevolutionary dynamics of host–parasite interactions. In this study, we utilized multi-locus microsatellite data to derive single-sample and temporal estimates of contemporary Ne for a cestode parasite (Schistocephalus solidus) as well as three-spined stickleback hosts (Gasterosteus aculeatus) in lakes across Alaska. Consistent with prior studies, both approaches recovered small and highly variable estimates of parasite and host Ne. We also found that estimates of host Ne and parasite Ne were sensitive to assumptions about population genetic structure and connectivity. And, while prior work on the stickleback–cestode system indicates that physiographic factors external to stickleback hosts largely govern genetic variation in S. solidus, our findings indicate that stickleback host attributes and factors internal to the host – namely body length, genetic diversity and infection – shape contemporary Ne of cestode parasites.
Studies involving clinically recruited samples show that genetic liability to schizophrenia overlaps with that for several psychiatric disorders including bipolar disorder, major depression and, in a population study, anxiety disorder and negative symptoms in adolescence.
We examined whether, at a population level, association between schizophrenia liability and anxiety disorders continues into adulthood, for specific anxiety disorders and as a group. We explored in an epidemiologically based cohort the nature of adult psychopathology sharing liability to schizophrenia.
Schizophrenia polygenic risk scores (PRSs) were calculated for 590 European-descent individuals from the Christchurch Health and Development Study. Logistic regression was used to examine associations between schizophrenia PRS and four anxiety disorders (social phobia, specific phobia, panic disorder and generalised anxiety disorder), schizophrenia/schizophreniform disorder, manic/hypomanic episode, alcohol dependence, major depression, and – using linear regression – total number of anxiety disorders. A novel population-level association with hypomania was tested in a UK birth cohort (Avon Longitudinal Study of Parents and Children).
Schizophrenia PRS was associated with total number of anxiety disorders and with generalised anxiety disorder and panic disorder. We show a novel population-level association between schizophrenia PRS and manic/hypomanic episode.
The relationship between schizophrenia liability and anxiety disorders is not restricted to psychopathology in adolescence but is present in adulthood and specifically linked to generalised anxiety disorder and panic disorder. We suggest that the association between schizophrenia liability and hypomanic/manic episodes found in clinical samples may not be due to bias.
Traditionally, personalised nutrition was delivered at an individual level. However, the concept of delivering tailored dietary advice at a group level through the identification of metabotypes or groups of metabolically similar individuals has emerged. Although this approach to personalised nutrition looks promising, further work is needed to examine this concept across a wider population group. Therefore, the objectives of this study are to: (1) identify metabotypes in a European population and (2) develop targeted dietary advice solutions for these metabotypes. Using data from the Food4Me study (n 1607), k-means cluster analysis revealed the presence of three metabolically distinct clusters based on twenty-seven metabolic markers including cholesterol, individual fatty acids and carotenoids. Cluster 2 was identified as a metabolically healthy metabotype as these individuals had the highest Omega-3 Index (6·56 (sd 1·29) %), carotenoids (2·15 (sd 0·71) µm) and lowest total saturated fat levels. On the basis of its fatty acid profile, cluster 1 was characterised as a metabolically unhealthy cluster. Targeted dietary advice solutions were developed per cluster using a decision tree approach. Testing of the approach was performed by comparison with the personalised dietary advice, delivered by nutritionists to Food4Me study participants (n 180). Excellent agreement was observed between the targeted and individualised approaches with an average match of 82 % at the level of delivery of the same dietary message. Future work should ascertain whether this proposed method could be utilised in a healthcare setting, for the rapid and efficient delivery of tailored dietary advice solutions.
Progress in ultrafast terahertz (THz) communications has been limited due to the lack of picosecond switchable modulators with sufficient modulation depth. Gallium arsenide nanowires are ideal candidates for THz modulators as they absorb THz radiation, only when photoexcited – giving the potential for picosecend speed switching and high modulation depth. By embedding the nanowires in a polymer matrix and laminating together several nanowire–polymer films, we increase the areal density of nanowires, resulting in greater modulation of THz radiation. In this paper, we compare PDMS and Parylene C polymers for nanowire encapsulation and show that a high modulation depth is possible using Parylene C due to its thinness and its ability to be laminated. We characterize the modulator behavior and switching speed using optical pump–THz probe spectroscopy, and demonstrate a parylene–nanowire THz modulator with 13.5% modulation depth and 1ps switching speed.
To determine whether use of contact precautions on hospital ward patients is associated with patient adverse events
Individually matched prospective cohort study
The University of Maryland Medical Center, a tertiary care hospital in Baltimore, Maryland
A total of 296 medical or surgical inpatients admitted to non–intensive care unit hospital wards were enrolled at admission from January to November 2010. Patients on contact precautions were individually matched by hospital unit after an initial 3-day length of stay to patients not on contact precautions. Adverse events were detected by physician chart review and categorized as noninfectious, preventable and severe noninfectious, and infectious adverse events during the patient’s stay using the standardized Institute for Healthcare Improvement’s Global Trigger Tool.
The cohort of 148 patients on contact precautions at admission was matched with a cohort of 148 patients not on contact precautions. Of the total 296 subjects, 104 (35.1%) experienced at least 1 adverse event during their hospital stay. Contact precautions were associated with fewer noninfectious adverse events (rate ratio [RtR], 0.70; 95% confidence interval [CI], 0.51–0.95; P=.02) and although not statistically significant, with fewer severe adverse events (RtR, 0.69; 95% CI, 0.46–1.03; P=.07). Preventable adverse events did not significantly differ between patients on contact precautions and patients not on contact precautions (RtR, 0.85; 95% CI, 0.59–1.24; P=.41).
Hospital ward patients on contact precautions were less likely to experience noninfectious adverse events during their hospital stay than patients not on contact precautions.
Infect. Control Hosp. Epidemiol. 2015;36(11):1268–1274
Food records or diaries, dietary recalls and FFQ are methods traditionally used to measure dietary intake; however, advancing technologies and growing awareness in personalised health have heightened interest in the application of new technologies to assess dietary intake. Dietary intake data can be used in epidemiology, dietary interventions and in the delivery of personalised nutrition advice. Compared with traditional dietary assessment methods, new technologies have many advantages, including their ability to automatically process data and provide personalised dietary feedback advice. This review examines the new technologies presently under development for the assessment of dietary intakes, and their utilisation and efficacy for personalising dietary advice. New technology-based methods of dietary assessment can broadly be categorised into three key areas: online (web-based) methods, mobile methods and sensor technologies. Several studies have demonstrated that utilising new technologies to provide tailored advice can result in positive dietary changes and have a significant impact on selected nutrient and food group intakes. However, comparison across studies indicates that the magnitude of change is variable and may be influenced by several factors, including the frequency and type of feedback provided. Future work should establish the most effective combinations of these factors in facilitating dietary changes across different population groups.
We report an experimental study of photocarrier lifetime, transport, and excitation spectra in silicon-on-insulator doped with sulfur far above thermodynamic saturation. The spectral dependence of photocurrent in coplanar structures is consistent with photocarrier generation throughout the hyperdoped and undoped sub-layers, limited by collection of holes transported along the undoped layer. Holes photoexcited in the hyperdoped layer are able to diffuse to the undoped layer, implying (μτ)h ∼ 5 × 10−9 cm2/V. Although high absorptance of hyperdoped silicon is observed from 1200 to 2000 nm in transmission experiments, the number of collected electrons per absorbed photon is 10−4 of the above-bandgap response of the device, consistent with (μτ)e < 1 × 10−7cm2/V.
Patients in the emergency department (ED) who have been admitted to hospital (inpatient “boarders”) are associated with ED overcrowding. They are also a symptom of a hospital-wide imbalance between demand and supply of resources. We analyzed the trends of inpatient admissions, ED boarding volumes, lengths of stay and bed resources of 3 major admitting services at our teaching institution.
We used hospital databases from Jan. 1, 2004, to Dec. 31, 2007, to analyze ED visits that resulted in admission to hospital.
During the study period, 21 986 ED patients were admitted to hospital. The percentage of cancer-related admissions to the oncology admitting service decreased from 48% in 2004 to 24% in 2007, and admissions to general internal medicine (GIM) increased nearly 2-fold, from 28% in 2004 to 54% in 2007. In addition, GIM admitted about 10% more myocardial infarction and heart failure patients than did cardiology. General internal medicine constituted the majority of ED boarders and had a median boarding length of stay of approximately 15 hours. Inpatient beds on oncology and cardiology services remained static.
Without bed capacity to admit more patients, our specialty services relied on GIM to serve as a safety net. At the same time, GIM was cited as a main source of ED congestion as their patients occupied more ED beds for longer periods than any other admitting service. The data presented in this study has helped effect positive change within our institution. Other hospitals running at or near capacity and faced with similar ED congestion may apply the methods we used in this study to analyze the cause and nature of their situation.
To describe an outbreak of infections with permanent cuffed hemodialysis catheters recognized through ongoing surveillance and related to a specific malfunctioning permanent catheter.
The outbreak was suspected from the results of prospective infection surveillance and confirmed by a retrospective cohort study using medical records for patients receiving dialysis between April 1,1999, and March 31, 2000.
Integrated network of six outpatient hemodialysis facilities in southern Idaho and eastern Oregon.
Outpatients receiving long-term hemodialysis.
During the 18 months prior to the outbreak, the overall infection rate was 4.1 infections per 1,000 dialysis sessions with a catheter rate of 8.9 per 1,000 dialysis sessions. During the 7 months of the outbreak, the overall rate increased to 5.8 per 1,000 dialysis sessions, whereas the catheter rate increased to 18.1 per 1,000 dialysis sessions. Reports of malfunctioning “Brand A” catheters prompted discontinuation of their placement. A manufacturer recall occurred in April 2000. During the 14 months after the outbreak, the overall infection rate decreased to 3.3 per 1,000 dialysis sessions and the catheter rate to 10.8 per 1,000 dialysis sessions. A 12-month retrospective cohort study recognized 96 patients with an identifiable catheter brand and 48 infections. Of these, 27 (56%) occurred in patients with Brand A catheters. The relative risk for infection when compared with other catheter brands was 1.96 (95% confidence interval, 1.32 to 2.92; P < .001).
Ongoing infection surveillance in hemodialysis facilities can identify specific device-related outbreaks of infections and promote interventions to reduce infectious complications and promote patient safety. Surveillance for vascular access site infections is recommended as a routine activity in hemodialysis facilities.
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