Size effects in ion-neutral complex-mediated alkane eliminations from ionized aliphatic ethers

AbstractThe effects of the size of the ionic and neutral partners on ion-neutral complex-mediated alkane eliminations from ionized aliphatic ethers were determined by obtaining metastable decomposition spectra and photoionization ionization efficiency curves. Increasing the size of the ionic partner decreases the competitiveness of alkane elimination with alkyl loss. This is attributed to decreasing attraction between the partners with increasing distance between the neutral partner and the center of charge in the associated ion. Increasing the size of the neutral partner lowers the threshold for alkane elimination relative to that for simple dissociation when the first threshold is above ΔHf(products). This is attributed to increasing attraction between the partners with increasing polarizability of the radical in the complex. Adding a CH2 to the radical in a complex seems to increase the attraction between the partners by about 24 kJ mol−1

Course-based Science Research Promotes Learning in Diverse Students at Diverse Institutions

Course-based research experiences (CREs) are powerful strategies for spreading learning and improving persistence for all students, both science majors and nonscience majors. Here we address the crucial components of CREs (context, discovery, ownership, iteration, communication, presentation) found across a broad range of such courses at a variety of academic institutions. We also address how the design of a CRE should vary according to the background of student participants; no single CRE format is perfect. We provide a framework for implementing CREs across multiple institutional types and several disciplines throughout the typical four years of undergraduate work, designed to a variety of student backgrounds. Our experiences implementing CREs also provide guidance on overcoming barriers to their implementation

Radio Frequency Tag Satellite: Backscatter Communication in Low Earth Orbit

Wireless sensor communication can evaluate the structural integrity of a system while reducing the danger and cost of installation and maintenance on satellites. This is needed at the International Space Station as well as other satellites. The objective of this mission is to perform a demonstration using backscatter Radio Frequency Identification (RFID) Tag technology as a method of wireless communication in extremely low earth orbit. While RFID tag communication has been used on earth for many practical applications the technology has yet to be tested in space. A 3U Cubesat was selected as the configuration to house the experiment. This project utilizes an electrical power system, an interface board custom built around a microcontroller, and two radio communication systems to run the RFID experiment to be designed by a Georgia Tech engineering team. The RFID tag will be mounted to a carbon fiber boom that can be extended out one meter to incrementally collect data. This satellite will need to be strong enough to pass a series of vibration and heat tests to be qualified for flight. It will be programmed to maintain its own power, take data, and communicate the data back to earth via the Globalstar Network

Cytotoxic edema associated with hemorrhage predicts poor outcome after traumatic brain injury

Magnetic resonance imaging (MRI) is rarely used in the acute evaluation of traumatic brain injury (TBI), but may identify findings of clinical importance not detected by computed tomography (CT). We aimed to characterize the association of cytotoxic edema and hemorrhage, including traumatic microbleeds, on MRI obtained within hours of acute head trauma and investigated the relationship to clinical outcomes. Patients prospectively enrolled in the Traumatic Head Injury Neuroimaging Classification study (NCT01132937) with evidence of diffusion-related findings or hemorrhage on neuroimaging were included. Blinded interpretation of MRI for diffusion-weighted imaging and hemorrhage was conducted, with subsequent quantification of apparent diffusion coefficient (ADC) values. Of 161 who met criteria, 82 patients had conspicuous hyperintense lesions on diffusion-weighted imaging (DWI) with corresponding regions of hypointense ADC in proximity to hemorrhage. Median time from injury to MRI was 21 (10-30) hours. Median ADC values per patient grouped by time from injury to MRI were lowest within 24 hours after injury. ADC values associated with hemorrhagic lesions are lowest early after injury, with an increase in diffusion during the subacute period, suggesting transformation from cytotoxic to vasogenic edema during the subacute post-injury period. Of 118 patients with outcome data, 60 had Glasgow Outcome Scale Extended <6 at 30/90 days post-injury. Cytotoxic edema on MRI (OR 2.91 [1.32-6.37], P=0.008) and TBI severity (OR 2.51 [1.32-4.74], P=0.005) were independent predictors of outcome. These findings suggest that in TBI patients with findings of hemorrhage on CT, patients with DWI/ADC lesions on MRI are more likely to do worse

NHS Health Check Programme rapid evidence synthesis

Background: The NHS Health Check programme is the largest current prevention initiative in England. Since its introduction in 2009 a growing literature has been published evaluating the first eight years of the programme. These have been summarised in reports published by Public Health England but, to date, no synthesis has been performed. There is, therefore, a need for an independent, comprehensive, rapid evidence synthesis to identify what has been learnt about the NHS Health Check programme so far. Aims and Objectives: To provide a rapid synthesis of the published research evidence on NHS Health Checks, specifically addressing the six research questions posed by Public Health England: 1. Who is and who is not having an NHS Health Check? 2. What are the factors that increase take-up among the population and sub-groups? 3. Why do people not take up an offer of an NHS Health Check? 4. How is primary care managing people identified as being at risk of cardiovascular disease or with abnormal risk factor results? 5. What are patients’ experiences of having an NHS Health Check? 6. What is the effect of the NHS Health Check on disease detection, changing behaviours, referrals to local risk management services, reductions in individual risk factor prevalence, reducing cardiovascular disease risk and on statin and antihypertensive prescribing? Design: A systematic review with descriptive synthesis of quantitative data and thematic synthesis of qualitative data. Data sources: Medline, PubMed, Embase, Health Management Information Consortium (HMIC), Cumulative Index of Nursing and Allied Health Literature (CINAHL), Global Health, PsycInfo, Web of Science, the Cochrane Library, NHS Evidence, Google Scholar, Google, OpenGrey, Clinical Trials.gov, the ISRCTN registry, and article reference lists. Study selection: Studies identified by the searches were selected for inclusion in the review by two reviewers in a two-step process. First, studies relevant to the NHS Health Check were identified. These were then screened against predefined inclusion and exclusion criteria for each of the six research questions. Data extraction: At least two researchers assessed eligibility, extracted data, and assessed the quality of the included studies. Key findings: Coverage varies substantially across regions and in different settings. Multiple definitions used interchangeably make comparisons difficult. It is consistently higher in older people, females and more deprived populations but this may reflect targeting. Outreach services in the community can reach particular socio-demographic groups but better descriptions and robust evaluations are needed. There is a lack of national level studies reporting the characteristics of those who take-up the invitation to an NHS Health Check. Regional studies report uptake between 27% and 53%, similar to national reported uptake (48.3%). Older people, women in younger age groups and men in older age groups, and those from least deprived areas are more likely to take up invitations. Promising methods to increase uptake are modifications to the invitation (3-4% increase), and text message invites or reminders (up to 9% increase). There is a lack of quantitative evidence for the effect of community settings on uptake but qualitative evidence highlights their convenience and the value of community ambassadors. People do not take up the offer of an NHS Health Check due to lack of awareness or knowledge, competing priorities, misunderstanding the purpose, an aversion to preventive medicine, difficulty getting an appointment with a GP, and concerns about privacy and confidentiality of pharmacies. Amongst attendees there are high levels of satisfaction (over 80%). Some reported attendance had acted as a wake-up call and precipitant for lifestyle changes. Others were left with feelings of unmet expectations, were confused about or unable to remember their risk scores, and found lifestyle advice too simplistic and un-personalised. There are wide variations in the process, delivery and content of NHS Health Checks across the country, in part due to different local implementation. Regardless of region or setting those delivering NHS Health Checks reported challenges with workload, IT, funding, and training. Amongst general practice professionals there were concerns about inequality of uptake and doubts about the evidence underpinning the programme and the cost-effectiveness. NHS Health Checks are associated with small increases in disease detection. There is very little data on behaviour change or referrals to lifestyle services. NHS Health Checks are associated with a 3-4% increase in prescribing of statins

Fiber Attachment Module Experiment (FAME): Using a Multiplexed Miniature Hollow Fiber Membrane Bioreactor Solution for Rapid Process Testing

Bioreactor research is mostly limited to continuous stirred-tank reactors (CSTRs) which are not an option for microgravity (g) applications due to the lack of a gravity gradient to drive aeration as described by the Archimedes principle. Bioreactors and filtration systems for treating wastewater in g could avoid the need for harsh pretreatment chemicals and improve overall water recovery. Solution: Membrane Aerated Bioreactors (MABRs) for g applications, including possible use for wastewater treatment systems for the International Space Station (ISS)

Natural variation and dosage of the HEI10 meiotic E3 ligase control Arabidopsis crossover recombination

During meiosis, homologous chromosomes undergo crossover recombination, which creates genetic diversity and balances homolog segregation. Despite these critical functions, crossover frequency varies extensively within and between species. Although natural crossover recombination modifier loci have been detected in plants, causal genes have remained elusive. Using natural Arabidopsis thaliana accessions, we identified two major recombination quantitative trait loci (rQTLs) that explain 56.9% of crossover variation in ColxLer F2 populations. We mapped rQTL1 to semidominant polymorphisms in HEI10, which encodes a conserved ubiquitin E3 ligase that regulates crossovers. Null hei10 mutants are haploinsufficient, and, using genome-wide mapping and immunocytology, we show that transformation of additional HEI10 copies is sufficient to more than double euchromatic crossovers. However, heterochromatic centromeres remained recombination-suppressed. The strongest HEI10-mediated crossover increases occur in subtelomeric euchromatin, which is reminiscent of sex differences in Arabidopsis recombination. Our work reveals that HEI10 naturally limits Arabidopsis crossovers and has the potential to influence the response to selection

The local FIR Galaxy Colour-Luminosity distribution: A reference for BLAST, and Herschel/SPIRE sub-mm surveys

We measure the local galaxy far-infrared (FIR) 60-to-100 um colour-luminosity distribution using an all-sky IRAS survey. This distribution is an important reference for the next generation of FIR--submillimetre surveys that have and will conduct deep extra-galactic surveys at 250--500 um. With the peak in dust-obscured star-forming activity leading to present-day giant ellipticals now believed to occur in sub-mm galaxies near z~2.5, these new FIR--submillimetre surveys will directly sample the SEDs of these distant objects at rest-frame FIR wavelengths similar to those at which local galaxies were observed by IRAS. We have taken care to correct for temperature bias and evolution effects in our IRAS 60 um-selected sample. We verify that our colour-luminosity distribution is consistent with measurements of the local FIR luminosity function, before applying it to the higher-redshift Universe. We compare our colour-luminosity correlation with recent dust-temperature measurements of sub-mm galaxies and find evidence for pure luminosity evolution of the form (1+z)^3. This distribution will be useful for the development of evolutionary models for BLAST and SPIRE surveys as it provides a statistical distribution of rest-frame dust temperatures for galaxies as a function of luminosity.Comment: 12 pages, 7 figures. MNRAS in press. This revision matches final published version. Fixes typos in footnote 1 and equation 8. Minor modifications to text and references. Final results unchange

Diarrhea as a potential cause and consequence of reduced gut microbial diversity among undernourished children in Peru

BACKGROUND: Detrimental effects of diarrhea on child growth and survival are well documented, but details of the underlying mechanisms remain poorly understood. Recent evidence demonstrates that perturbations to normal development of the gut microbiota in early life may contribute to growth faltering and susceptibility to related childhood diseases. We assessed associations between diarrhea, gut microbiota configuration, and childhood growth in the Peruvian Amazon. METHODS: Growth, diarrhea incidence, illness, pathogen infection, and antibiotic exposure were assessed monthly in a birth cohort of 271 children aged 0-24 months. Gut bacterial diversity and abundances of specific bacterial taxa were quantified by sequencing 16S rRNA genes in fecal samples collected at 6, 12, 18, and 24 months. Linear and generalized linear models were used to determine whether diarrhea was associated with altered microbiota and, in turn, if features of the microbiota were associated with the subsequent risk of diarrhea. RESULTS: Diarrheal frequency, duration, and severity were negatively associated with bacterial diversity and richness (P \u3c .05). Children born stunted (length-for-age z-score [LAZ] ≤ -2) who were also severely stunted (LAZ ≤ -3) at the time of sampling exhibited the greatest degree of diarrhea-associated reductions in bacterial diversity and the slowest recovery of bacterial diversity after episodes of diarrhea. Increased bacterial diversity was predictive of reduced subsequent diarrhea from age 6 to 18 months. CONCLUSIONS: Persistent, severe growth faltering may reduce the gut microbiota\u27s resistance and resilience to diarrhea, leading to greater losses of diversity and longer recovery times. This phenotype, in turn, denotes an increased risk of future diarrheal disease and growth faltering

The star formation history of mass-selected galaxies from the VIDEO survey

© 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical SocietyWe measure star formation rates (SFRs) and specific SFRs (SSFRs) of Ks-selected galaxies from the VISTA Deep Extragalactic Observations survey by stacking 1.4 GHz Very Large Array data.We split the sample, which spans 0 < z<3 and stellar masses 108.0 < M*/M⊙ < 1011.5, into elliptical, irregular or starburst galaxies based on their spectral energy distributions. We find that SSFR falls with stellar mass, in agreement with the 'downsizing' paradigm. We consider the dependence of the SSFR-mass slope on redshift: for our full and elliptical samples the slope flattens, but for the irregular and starburst samples the slope is independent of redshift. The rate of SSFR evolution reduces slightly with stellar mass for ellipticals, but irregulars and starbursts co-evolve across stellar masses. Our results for SSFR as a function of stellar mass and redshift are in agreement with those derived from other radio-stacking measurements of mass-selected passive and star-forming galaxies, but inconsistent with those generated from semi-analytic models, which tend to underestimate SFRs and SSFRs. There is a need for deeper high-resolution radio surveys such as those from telescopes like the next-generation MeerKAT in order to probe lower masses at earlier times and to permit direct detections, i.e. to study individual galaxies in detail.Peer reviewe