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The smr and qacA/B genes in Staphylococcus aureus confer tolerance to antiseptics and are associated with nosocomial acquisition of infection and underlying medical conditions. Such antiseptic tolerance (AT) genes have also been reported in coagulase-negative staphylococci (CoNS) and enterococci, however, few data are available regarding their prevalence. We sought to describe the frequency of AT genes among bloodstream isolates of S. aureus, CoNS and enterococci at Texas Children’s Hospital (TCH).
Banked CoNS, S. aureus and enterococci isolated from blood cultures collected bewteen October 1, 2016, and October 1, 2017, were obtained from the TCH clinical microbiology laboratory. All isolates underwent polymerase chain reaction (PCR) assay for the qacA/B and smr genes. Medical records were reviewed for all cases.
In total, 103 CoNS, 19 Enterococcus spp, and 119 S. aureus isolates were included in the study, and 80.6% of the CoNS possessed at least 1 AT gene compared to 37% of S. aureus and 43.8% of E. faecalis isolates (P < .001). Among CoNS bloodstream isolates, the presence of either AT gene was strongly associated with nosocomial infection (P < .001). The AT genes in S. aureus were associated with nosocomial infection (P = .025) as well as the diagnosis of central-line–associated bloodstream infection (CLABSI; P = .04) and recent hospitalizations (P < .001). We found no correlation with genotypic AT in E. faecalis and any clinical variable we examined.
Antiseptic tolerance is common among bloodstream staphylococci and E. faecalis isolates at TCH. Among CoNS, the presence of AT genes is strongly correlated with nosocomial acquisition of infection, consistent with previous studies in S. aureus. These data suggest that the healthcare environment contributes to AT among staphylococci.
The southern Cape of South Africa is important to understanding regional climate because it straddles the transition between the winter and summer rainfall zones. We examine late Quaternary changes in rainfall seasonality and aridity through analysis of micromammal assemblages from three sites: Boomplaas Cave and Nelson Bay Cave in the aseasonal rainfall zone and Byneskranskop 1 in the winter rainfall zone. Our interpretation is based on analysis of 123 modern micromammal assemblages accumulated by barn owls (Tyto alba), which empirically links species composition to climate. The Pleistocene record (∼65 to 12 ka) from Boomplaas Cave, together with the last glacial maximum (LGM) samples from Nelson Bay Cave, indicates enhanced winter rainfall, especially during the LGM. Boomplaas Cave documents progressive aridification from the LGM to the earliest Holocene, followed by a return to moderately humid conditions through the Holocene. Byneskranskop 1 indicates a dominance of winter rains over the last 17 ka and a shift from an arid middle Holocene to a humid later Holocene. Agreement between the micromammal record and other local and regional proxies reinforces the potential of southern African micromammal assemblages as paleoclimate indicators.
This paper analyses a series of high-quality continuous records from southeastern Africa to study the spatiotemporal patterning of Holocene hydroclimatic anomalies in the region. Results indicate dominant frequencies of variability at millennial time scales, and a series of anomalies broadly common to all records. Of particular interest, data from the southern Cape coast exhibit periods of wetter/drier conditions that are out of phase with the sites less than 150 km away in the adjacent interior, but in phase with sites in tropical regions over 1000 km to the northeast. To explain such spatial patterns and gradients, we propose that the Agulhas Current may be a critical vector by which tropical climatic signals are propagated along the littoral zone, exerting a dominant, highly localized influence on near-coastal environmental conditions. Limitations in the data available do not allow for a detailed examination of the climatic dynamics related to these phenomena, but this paper highlights a series of avenues for future research to clarify the spatial extent and stability of the patterns observed.
Escherichia coli O157 are zoonotic bacteria for which cattle are an important reservoir. Prevalence estimates for E. coli O157 in British cattle for human consumption are over 10 years old. A new baseline is needed to inform current human health risk. The British E. coli O157 in Cattle Study (BECS) ran between September 2014 and November 2015 on 270 farms across Scotland and England & Wales. This is the first study to be conducted contemporaneously across Great Britain, thus enabling comparison between Scotland and England & Wales. Herd-level prevalence estimates for E. coli O157 did not differ significantly for Scotland (0·236, 95% CI 0·166–0·325) and England & Wales (0·213, 95% CI 0·156–0·283) (P = 0·65). The majority of isolates were verocytotoxin positive. A higher proportion of samples from Scotland were in the super-shedder category, though there was no difference between the surveys in the likelihood of a positive farm having at least one super-shedder sample. E. coli O157 continues to be common in British beef cattle, reaffirming public health policy that contact with cattle and their environments is a potential infection source.
Data obtained by the AS&E X-ray Telescope Experiment during the first Skylab mission have revealed a variety of temporal changes in both the form and brightness of coronal structures. Dynamical changes have been noted in active regions, in large scale coronal structures, and in coronal bright points. The coronal activity accompanying a series of Hα flares and prominence activity between 0800 and 1600 UT on 10 June 1973 in active region 137 (NOAA) at the east limb is shown in Figure 1. It is characterized by increases in the brightness and temperature of active region loops and a dramatic change in the shape and brightness of a loop structure. Figure 2 shows the reconfiguration of an apparent polar crown filament cavity between 1923 UT on 12 June 1973 and 1537 UT on 13 June 1973. A ridge of emitting material which attains a peak brightness at least four times that of the surrounding coronal structures appears within the cavity during the course of the event. Typical X-ray photographs with filters passing relatively soft X-ray wavelengths (3–32, 44–54 Å) show 90 to 100 X-ray bright points (Vaiana et al., 1973). On twelve occasions in the data from the first mission, such bright points were seen to increase in intensity by two orders of magnitude in less than 4 min. Such an event is shown in Figure 3.
Weeds represent a major cause of agricultural losses worldwide. Most weeds
share a common set of life history characteristics that predispose them to
weediness, two of which are self-compatibility, which allows for ease of
colonization through reproductive assurance, and high trait plasticity,
which allows for tolerance of a wide variety of environments and abiotic
conditions. However, self-fertilization typically comes at the cost of
inbreeding depression. This study investigates the role of inbreeding
depression and trait plasticity under abiotic stress in the tall
morningglory, a widespread self-compatible agricultural weed in the
southeastern United States. Results show very little inbreeding depression
in this species, likely due to purging of deleterious alleles through
repeated founder events in agricultural landscapes. In contrast, abiotic
stress induced substantial plasticity in ecophysiological traits,
reproductive traits, and biomass allocation. In terms of performance,
drought sharply impacted reproduction but not vegetative growth, and
nitrogen limitation sharply impacted both. These findings are applicable to
the control of weedy morningglory and underscore the usefulness of
evolutionary ecology to weed management.
The objective of this study was to evaluate the impact of a brief parenting intervention, ‘Parents Make the Difference‘(PMD), on parenting behaviors, quality of parent-child interactions, children's cognitive, emotional, and behavioral wellbeing, and malaria prevention behaviors in rural, post-conflict Liberia.
A sample of 270 caregivers of children ages 3–7 were randomized into an immediate treatment group that received a 10-session parent training intervention or a wait-list control condition (1:1 allocation). Interviewers administered baseline and 1-month post-intervention surveys and conducted child-caregiver observations. Intent-to-treat estimates of the average treatment effects were calculated using ordinary least squares regression. This study was pre-registered at ClinicalTrials.gov (NCT01829815).
The program led to a 55.5% reduction in caregiver-reported use of harsh punishment practices (p < 0.001). The program also increased the use of positive behavior management strategies and improved caregiver–child interactions. The average caregiver in the treatment group reported a 4.4% increase in positive interactions (p < 0.05), while the average child of a caregiver assigned to the treatment group reported a 17.5% increase (p < 0.01). The program did not have a measurable impact on child wellbeing, cognitive skills, or household adoption of malaria prevention behaviors.
PMD is a promising approach for preventing child abuse and promoting positive parent-child relationships in low-resource settings.
The use of airborne LiDAR (Light Detection and Ranging) in western Belize, Central America, has revolutionized our understanding of the spatial dynamics of the ancient Maya. This technology has enabled researchers to successfully demonstrate the large-scale human modifications made to the ancient tropical landscape, providing insight on broader regional settlement. Before the advent of this laser-based technology, heavily forested cover prevented full coverage and documentation of Maya sites. Mayanists could not fully recover or document the extent of ancient occupation and could never be sure how representative their mapped and excavated samples were relative to ancient settlement. Employing LiDAR in tropical and subtropical environments, like that of the Maya, effectively provides ground, as well as forest cover information, leading to a much fuller documentation of the complexities involved in the ancient human-nature interface. Airborne LiDAR was first flown over a 200 km2 area of the archaeological site of Caracol, Belize, in April 2009. In April and May 2013 an additional 1,057 km2 were flown with LiDAR, permitting the contextualization of the city of Caracol within its broader region and polity. The use of this technology has transformed our understanding of regional archaeology in the Maya area.
Migrations of most animal taxa are declining as a result of anthropogenic pressures and land-use transformation. Here, we document and characterize a previously unknown multi-country migration of Burchell's zebra Equus quagga that is the longest of all recorded large mammal migrations in Africa. Our data from eight adult female zebras collared on the border of Namibia and Botswana show that in December 2012 all individuals crossed the Chobe River and moved due south to Nxai Pan National Park in Botswana, where they spent a mean duration of 10 weeks before returning, less directly, to their dry season floodplain habitat. The same southward movements were also observed in December 2013. Nxai Pan appeared to have similar environmental conditions to several possible alternative wet season destinations that were closer to the dry season habitat on the Chobe River, and water availability, but not habitat or vegetation biomass, was associated with higher-use areas along the migratory pathway. These results suggest a genetic and/or cultural basis for the choice of migration destination, rather than an environmental one. Regardless of the cause, the round-trip, straight-line migration distance of 500 km is greater than that covered by wildebeest Connochaetes taurinus during their well-known seasonal journey in the Serengeti ecosystem. It merits conservation attention, given the decline of large-scale ecological processes such as animal migrations.
Negative biases in emotional processing are well recognised in people who are currently depressed but are less well described in those with a history of depression, where such biases may contribute to vulnerability to relapse.
To compare accuracy, discrimination and bias in face emotion recognition in those with current and remitted depression.
The sample comprised a control group (n = 101), a currently depressed group (n = 30) and a remitted depression group (n = 99). Participants provided valid data after receiving a computerised face emotion recognition task following standardised assessment of diagnosis and mood symptoms.
In the control group women were more accurate in recognising emotions than men owing to greater discrimination. Among participants with depression, those in remission correctly identified more emotions than controls owing to increased response bias, whereas those currently depressed recognised fewer emotions owing to decreased discrimination. These effects were most marked for anger, fear and sadness but there was no significant emotion × group interaction, and a similar pattern tended to be seen for happiness although not for surprise or disgust. These differences were confined to participants who were antidepressant-free, with those taking antidepressants having similar results to the control group.
Abnormalities in face emotion recognition differ between people with current depression and those in remission. Reduced discrimination in depressed participants may reflect withdrawal from the emotions of others, whereas the increased bias in those with a history of depression could contribute to vulnerability to relapse. The normal face emotion recognition seen in those taking medication may relate to the known effects of antidepressants on emotional processing and could contribute to their ability to protect against depressive relapse.
Study of relevant types has led to the conclusion that Gagea kunawurensis (Royle) Greuter (Liliaceae) is the correct name for what has recently been known as G. stipitata Merckl. ex Bunge; that G. gageoides (Zucc.) Vved. is the correct name for G. persica Boiss., and that G. kashmirensis Turrill should be reduced to synonymy of G. tenera Pascher. Anatomical and morphological data are presented for these and the related species Gagea dschungarica Regel and G. afghanica A.Terracc., and a key given to allow their discrimination.
Raman scattering measurements of Bi clusters formed on disordered C films at 110K exhibit a phase transformation from nanocrystalline rhombohedral structure to a suggested disordered phase. XPS measurements on this phase indicate core level shifts attributed to intrinsic, initial state effects on cluster electronic states.
Raman scattering measurements in alkali—fullerene alloys in ultrathin and thin films provide evidence for variations in electron—phonon coupling. For x — 3similar behavior of Rb3 C60 films of different thickness support substantial electron—phonon induced damping of specific Hg(i) modes derived from intramolecular modes of C60. In 400A thick films a reduction of induced scattering from Raman inactive C60 modes substantiates the importance ofHg(2), but not Hg(3) modes for phonon—mediated superconductivity. In contrast to RbxC60 and KxC60 ultrathin film solid solutions, similar Raman spectra for NaxC60 indicate substantially reduced coupling consistent with the absence of superconductivity in this system.
Si nanocrystallites have been prepared by ultrasonicating thin sections of porous silicon. The materials produced from 20 and 49 wt % HF are characterized and compared. Samples were characterized by optical absorption and photoluminescence spectroscopy, and HRTEM.
Density of states changes in the valence and conduction band of silicon nanoclusters were monitored using soft x-ray emission and absorption spectroscopy as a function of cluster size. A progressive increase in the valence band edge toward lower energy is found for clusters with decreasing diameters. A similar but smaller shift is observed in the near-edge x-ray absorption data of the silicon nanoclusters.
Laser ablation and post annealing was employed for the synthesis of silicon (Si) clusters on highly oriented pyrolytic graphite surfaces in an ultra high-vacuum environment. The size distribution of the clusters was determined as a function of annealing time and temperature using an in situ scanning tunneling microscope (STM). Pure Si clusters with sizes ranging from 1 to 10 nm showed no detectable photoluminescence (PL) in the visible range. Exposure of these clusters to oxygen at 10−6 Torr and for up to 8 hours showed adsorption of oxygen on the surface of the clusters without Si oxide formation and no detectable PL. Hydrogen termination of these clusters was accomplished by exposing them to atomic hydrogen beam but did not result in any detection of the PL spectra either. Prolonged exposure of these clusters to ambient air, however, resulted in strong PL spectra with color ranging from red to greenish-blue depending on average cluster size. Auger electron spectra (AES) revealed the existence of partially oxidized Si clusters for these samples. This PL could be due to either an oxide phase or to quantum confined Si inner cores.
Si nanoclusters with average size of a few nanometers have been synthesized by thermal vaporization of Si in an Ar buffer gas, and passivated with oxygen or atomic hydrogen. High resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) revealed that these nanoclusters were crystalline. All samples showed strong infrared and/or visible photoluminescence (PL) with varying decay times from nanoseconds to microseconds depending on synthesis conditions. Absorption mainly in the Si cores was observed by photoluminescence excitation (PLE) spectroscopy. The visible components of PL spectra were noted to blue shift and broaden as the size of the Si nanocrystals (nc-Si) was reduced, and there were differences in PL spectra for hydrogen and oxygen passivated nc-Si. Our data can be explained best by a model involving absorption between quantum confined states in the Si cores and emission by surface/interface states.
Presented here are stable nitrogen isotope data from a rock hyrax (Procavia capensis) middens from northwestern Namibia that record a series of rapid aridification events beginning at ca. 3800 cal yr BP, and which mark a progressive decrease in regional humidity across the Holocene. Strong correlations exist between this record and other terrestrial and marine archives from southern Africa, indicating that the observed pattern of climate change is regionally coherent. Combined, these data indicate hemispheric synchrony in tropical African climate change during the Holocene, with similar trends characterising the termination of the ‘African Humid Period’ (AHP) in both the northern and southern tropics. These findings run counter to the widely accepted model of direct low-latitude insolation forcing, which requires an anti-phase relationship to exist between the hemispheres. The combined dataset highlights: 1) the importance of forcing mechanisms influencing the high northern latitudes in effecting low-latitude climate change in Africa, and 2) the potential importance of solar forcing and variations in the Earth's geomagnetic shield in determining both long-term and rapid centennial-scale climate changes, identifying a possible mechanism for the variations marking the AHP termination in both the southern and northern tropics.