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The effort to develop metallic alloys with increased structural strength and improved radiation performance has focused on the incorporation of either solute elements or microstructural inhomogeneities to mitigate damage. The recent discovery and development of single-phase concentrated solid-solution alloys (SP-CSAs) has prompted fundamental questions that challenge established theories and models currently applicable to conventional alloys. The current understanding of electronic and atomic effects, defect evolution, and microstructure progression suggests that radiation energy dissipates in SP-CSAs at different interaction strengths via energy carriers (electrons, phonons, and magnons). Modification of electronic- and atomic-level heterogeneities and tailoring of atomic transport processes can be realized through tuning of the chemical complexity of SP-CSAs by the selection of appropriate elements and their concentrations. Fundamental understanding of controlling energy dissipation via site-to-site chemical complexity reveals new design principles for predictive discovery and guided synthesis of new alloys with targeted functionalities, including radiation tolerance.
Sorghum (Sorghum bicolor (L.) Moench) is an important resource to the national economy and it is essential to assess the genetic diversity in existing sorghum germplasm for better conservation, utilization and crop improvement. The aim of this study was to evaluate the level of genetic diversity within and among sorghum germplasms collected from diverse institutes in Nigeria and Mali using Single Nucleotide Polymorphic markers. Genetic diversity among the germplasm was low with an average polymorphism information content value of 0.24. Analysis of Molecular Variation revealed 6% variation among germplasm and 94% within germplasms. Dendrogram revealed three groups of clustering which indicate variations within the germplasms. Private alleles identified in the sorghum accessions from National Center for Genetic Resources and Biotechnology, Ibadan, Nigeria and International Crop Research Institute for the Semi-Arid Tropics, Kano, Nigeria shows their prospect for sorghum improvement and discovery of new agronomic traits. The presence of private alleles and genetic variation within the germplasms indicates that the accessions are valuable resources for future breeding programs.
Multiple studies have demonstrated that daily chlorhexidine gluconate (CHG) bathing is associated with a significant reduction in infections caused by gram-positive pathogens. However, there are limited data on the effectiveness of daily CHG bathing on gram-negative infections. The aim of this study was to determine whether daily CHG bathing is effective in reducing the rate of gram-negative infections in adult intensive care unit (ICU) patients.
We searched MEDLINE and 3 other databases for original studies comparing daily bathing with and without CHG. Two investigators extracted data independently on baseline characteristics, study design, form and concentration of CHG, incidence, and outcomes related to gram-negative infections. Data were combined using a random-effects model and pooled relative risk ratios (RRs), and 95% confidence intervals (CIs) were derived.
In total, 15 studies (n = 34,895 patients) met inclusion criteria. Daily CHG bathing was not significantly associated with a lower risk of gram-negative infections compared with controls (RR, 0.89; 95% CI, 0.73–1.08; P = .24). Subgroup analysis demonstrated that daily CHG bathing was not effective for reducing the risk of gram-negative infections caused by Acinetobacter, Escherichia coli, Klebsiella, Enterobacter, or Pseudomonas spp.
The use of daily CHG bathing was not associated with a lower risk of gram-negative infections. Further, better designed trials with adequate power and with gram-negative infections as the primary end point are needed.
Contaminated hands of healthcare workers (HCWs) are an important source of transmission of healthcare-associated infections. Alcohol-based hand sanitizers, while effective, do not provide sustained antimicrobial activity. The objective of this study was to compare the immediate and persistent activity of 2 hand hygiene products (ethanol [61% w/v] plus chlorhexidine gluconate [CHG; 1.0% solution] and ethanol only [70% v/v]) when used in an intensive care unit (ICU).
Prospective, randomized, double-blinded, crossover study
Three ICUs at a large teaching hospital
In total, 51 HCWs involved in direct patient care were enrolled in and completed the study.
All HCWs were randomized 1:1 to either product. Hand prints were obtained immediately after the product was applied and again after spending 4–7 minutes in the ICU common areas prior to entering a patient room or leaving the area. The numbers of aerobic colony-forming units (CFU) were compared for the 2 groups after log transformation. Each participant tested the alternative product after a 3-day washout period.
On bare hands, use of ethanol plus CHG was associated with significantly lower recovery of aerobic CFU, both immediately after use (0.27 ± 0.05 and 0.88 ± 0.08 log10 CFU; P = .035) and after spending time in ICU common areas (1.81 ± 0.07 and 2.17 ± 0.05 log10 CFU; P<.0001). Both the antiseptics were well tolerated by HCWs.
In comparison to the ethanol-only product, the ethanol plus CHG sanitizer was associated with significantly lower aerobic bacterial counts on hands of HCWs, both immediately after use and after spending time in ICU common areas.
We observed single pulses from PSR J0034-0721 (B0031-07) simultaneously at the MWA (185 MHz) and the GMRT (610 MHz). Correlation analyses reveal that the phase difference of the average profiles at the two frequencies differs from the phase difference observed between individual subpulses, indicating that the individual emission columns above the pulsar’s rotating carousel of sparks do not evolve in frequency in the same way that the global magnetosphere does. This hints at a possible departure from the dipolar field geometry in this pulsar’s emission region. Moreover, the discrepancy depends on the drift mode, suggestive of a way to constrain the emission heights associated with each drift mode.
To determine the impact of an environmental disinfection intervention on the incidence of healthcare-associated Clostridium difficile infection (CDI).
A multicenter randomized trial.
In total,16 acute-care hospitals in northeastern Ohio participated in the study.
We conducted a 12-month randomized trial to compare standard cleaning to enhanced cleaning that included monitoring of environmental services (EVS) personnel performance with feedback to EVS and infection control staff. We assessed the thoroughness of cleaning based on fluorescent marker removal from high-touch surfaces and the effectiveness of disinfection based on environmental cultures for C. difficile. A linear mixed model was used to compare CDI rates in the intervention and postintervention periods for control and intervention hospitals. The primary outcome was the incidence of healthcare-associated CDI.
Overall, 7 intervention hospitals and 8 control hospitals completed the study. The intervention resulted in significantly increased fluorescent marker removal in CDI and non-CDI rooms and decreased recovery of C. difficile from high-touch surfaces in CDI rooms. However, no reduction was observed in the incidence of healthcare-associated CDI in the intervention hospitals during the intervention and postintervention periods. Moreover, there was no correlation between the percentage of positive cultures after cleaning of CDI or non-CDI rooms and the incidence of healthcare-associated CDI.
An environmental disinfection intervention improved the thoroughness and effectiveness of cleaning but did not reduce the incidence of healthcare-associated CDI. Thus, interventions that focus only on improving cleaning may not be sufficient to control healthcare-associated CDI.
There is a need for clinical tools to identify cultural issues in diagnostic assessment.
To assess the feasibility, acceptability and clinical utility of the DSM-5 Cultural Formulation Interview (CFI) in routine clinical practice.
Mixed-methods evaluation of field trial data from six countries. The CFI was administered to diagnostically diverse psychiatric out-patients during a diagnostic interview. In post-evaluation sessions, patients and clinicians completed debriefing qualitative interviews and Likert-scale questionnaires. The duration of CFI administration and the full diagnostic session were monitored.
Mixed-methods data from 318 patients and 75 clinicians found the CFI feasible, acceptable and useful. Clinician feasibility ratings were significantly lower than patient ratings and other clinician-assessed outcomes. After administering one CFI, however, clinician feasibility ratings improved significantly and subsequent interviews required less time.
The CFI was included in DSM-5 as a feasible, acceptable and useful cultural assessment tool.
We have compiled a catalogue of H ii regions detected with the Murchison Widefield Array between 72 and 231 MHz. The multiple frequency bands provided by the Murchison Widefield Array allow us identify the characteristic spectrum generated by the thermal Bremsstrahlung process in H ii regions. We detect 306 H ii regions between 260° < l < 340° and report on the positions, sizes, peak, integrated flux density, and spectral indices of these H ii regions. By identifying the point at which H ii regions transition from the optically thin to thick regime, we derive the physical properties including the electron density, ionised gas mass, and ionising photon flux, towards 61 H ii regions. This catalogue of H ii regions represents the most extensive and uniform low frequency survey of H ii regions in the Galaxy to date.
Using a national database, we report an increasing trend in Clostridium difficile incidence among hospitalized children in the United States from 2003 to 2012. The incidence rate of CDI increased from 24.0 to 58.0 per 10,000 discharges per year (P<0.001) across all age groups, with the greatest increase in children 15 years and older.
Infect. Control Hosp. Epidemiol. 2015;37(1):104–106
We compare first-order (refractive) ionospheric effects seen by the MWA with the ionosphere as inferred from GPS data. The first-order ionosphere manifests itself as a bulk position shift of the observed sources across an MWA field of view. These effects can be computed from global ionosphere maps provided by GPS analysis centres, namely the CODE. However, for precision radio astronomy applications, data from local GPS networks needs to be incorporated into ionospheric modelling. For GPS observations, the ionospheric parameters are biased by GPS receiver instrument delays, among other effects, also known as receiver DCBs. The receiver DCBs need to be estimated for any non-CODE GPS station used for ionosphere modelling. In this work, single GPS station-based ionospheric modelling is performed at a time resolution of 10 min. Also the receiver DCBs are estimated for selected Geoscience Australia GPS receivers, located at Murchison Radio Observatory, Yarragadee, Mount Magnet and Wiluna. The ionospheric gradients estimated from GPS are compared with that inferred from MWA. The ionospheric gradients at all the GPS stations show a correlation with the gradients observed with the MWA. The ionosphere estimates obtained using GPS measurements show promise in terms of providing calibration information for the MWA.
GLEAM, the GaLactic and Extragalactic All-sky MWA survey, is a survey of the entire radio sky south of declination + 25° at frequencies between 72 and 231 MHz, made with the MWA using a drift scan method that makes efficient use of the MWA’s very large field-of-view. We present the observation details, imaging strategies, and theoretical sensitivity for GLEAM. The survey ran for two years, the first year using 40-kHz frequency resolution and 0.5-s time resolution; the second year using 10-kHz frequency resolution and 2 s time resolution. The resulting image resolution and sensitivity depends on observing frequency, sky pointing, and image weighting scheme. At 154 MHz, the image resolution is approximately 2.5 × 2.2/cos (δ + 26.7°) arcmin with sensitivity to structures up to ~ 10° in angular size. We provide tables to calculate the expected thermal noise for GLEAM mosaics depending on pointing and frequency and discuss limitations to achieving theoretical noise in Stokes I images. We discuss challenges, and their solutions, that arise for GLEAM including ionospheric effects on source positions and linearly polarised emission, and the instrumental polarisation effects inherent to the MWA’s primary beam.
The Murchison Widefield Array is a Square Kilometre Array Precursor. The telescope is located at the Murchison Radio–astronomy Observatory in Western Australia. The MWA consists of 4 096 dipoles arranged into 128 dual polarisation aperture arrays forming a connected element interferometer that cross-correlates signals from all 256 inputs. A hybrid approach to the correlation task is employed, with some processing stages being performed by bespoke hardware, based on Field Programmable Gate Arrays, and others by Graphics Processing Units housed in general purpose rack mounted servers. The correlation capability required is approximately 8 tera floating point operations per second. The MWA has commenced operations and the correlator is generating 8.3 TB day−1 of correlation products, that are subsequently transferred 700 km from the MRO to Perth (WA) in real-time for storage and offline processing. In this paper, we outline the correlator design, signal path, and processing elements and present the data format for the internal and external interfaces.
The Murchison Widefield Array is a new low-frequency interferometric radio telescope built in Western Australia at one of the locations of the future Square Kilometre Array. We describe the automated radio-frequency interference detection strategy implemented for the Murchison Widefield Array, which is based on the aoflagger platform, and present 72–231 MHz radio-frequency interference statistics from 10 observing nights. Radio-frequency interference detection removes 1.1% of the data. Radio-frequency interference from digital TV is observed 3% of the time due to occasional ionospheric or atmospheric propagation. After radio-frequency interference detection and excision, almost all data can be calibrated and imaged without further radio-frequency interference mitigation efforts, including observations within the FM and digital TV bands. The results are compared to a previously published Low-Frequency Array radio-frequency interference survey. The remote location of the Murchison Widefield Array results in a substantially cleaner radio-frequency interference environment compared to Low-Frequency Array’s radio environment, but adequate detection of radio-frequency interference is still required before data can be analysed. We include specific recommendations designed to make the Square Kilometre Array more robust to radio-frequency interference, including: the availability of sufficient computing power for radio-frequency interference detection; accounting for radio-frequency interference in the receiver design; a smooth band-pass response; and the capability of radio-frequency interference detection at high time and frequency resolution (second and kHz-scale respectively).
The science cases for incorporating high time resolution capabilities into modern radio telescopes are as numerous as they are compelling. Science targets range from exotic sources such as pulsars, to our Sun, to recently detected possible extragalactic bursts of radio emission, the so-called fast radio bursts (FRBs). Originally conceived purely as an imaging telescope, the initial design of the Murchison Widefield Array (MWA) did not include the ability to access high time and frequency resolution voltage data. However, the flexibility of the MWA’s software correlator allowed an off-the-shelf solution for adding this capability. This paper describes the system that records the 100 μs and 10 kHz resolution voltage data from the MWA. Example science applications, where this capability is critical, are presented, as well as accompanying commissioning results from this mode to demonstrate verification.
An estimated 20–30% of patients with primary Clostridium difficile infection (CDI) develop recurrent CDI (rCDI) within 2 weeks of completion of therapy. While the actual mechanism of recurrence remains unknown, a variety of risk factors have been suggested and studied. The aim of this systematic review and meta-analysis was to evaluate current evidence on the risk factors for rCDI.
We searched MEDLINE and 5 other databases for subject headings and text related to rCDI. All studies investigating risk factors of rCDI in a multivariate model were eligible. Information on study design, patient population, and assessed risk factors were collected. Data were combined using a random-effects model and pooled relative risk ratios (RRs) were calculated.
A total of 33 studies (n=18,530) met the inclusion criteria. The most frequent independent risk factors associated with rCDI were age≥65 years (risk ratio [RR], 1.63; 95% confidence interval [CI], 1.24–2.14; P=.0005), additional antibiotics during follow-up (RR, 1.76; 95% CI, 1.52–2.05; P<.00001), use of proton-pump inhibitors (PPIs) (RR, 1.58; 95% CI, 1.13–2.21; P=.008), and renal insufficiency (RR, 1.59; 95% CI, 1.14–2.23; P=.007). The risk was also greater in patients previously on fluoroquinolones (RR, 1.42; 95% CI, 1.28–1.57; P<.00001).
Multiple risk factors are associated with the development of rCDI. Identification of modifiable risk factors and judicious use of antibiotics and PPI can play an important role in the prevention of rCDI.
We present the results of an approximately 6 100 deg2 104–196 MHz radio sky survey performed with the Murchison Widefield Array during instrument commissioning between 2012 September and 2012 December: the MWACS. The data were taken as meridian drift scans with two different 32-antenna sub-arrays that were available during the commissioning period. The survey covers approximately 20.5 h < RA < 8.5 h, − 58° < Dec < −14°over three frequency bands centred on 119, 150 and 180 MHz, with image resolutions of 6–3 arcmin. The catalogue has 3 arcmin angular resolution and a typical noise level of 40 mJy beam− 1, with reduced sensitivity near the field boundaries and bright sources. We describe the data reduction strategy, based upon mosaicked snapshots, flux density calibration, and source-finding method. We present a catalogue of flux density and spectral index measurements for 14 110 sources, extracted from the mosaic, 1 247 of which are sub-components of complexes of sources.
OxyCide Daily Disinfectant Cleaner, a novel peracetic acid/hydrogen peroxide–based sporicidal disinfectant, was as effective as sodium hypochlorite for in vitro killing of Clostridium difficile spores, methicillin-resistant Staphylococcus aureus, and vancomcyin-resistant enterococci. OxyCide was minimally affected by organic load and was effective in reducing pathogen contamination in isolation rooms
Infect Control Hosp Epidemiol 2014;35(11):1414–1416