SDSS J142625.71+575218.3: A Prototype for A New Class of Variable White Dwarf

We present the results of a search for pulsations in six of the recently discovered carbon-atmosphere white dwarf ("hot DQ") stars. On the basis of our theoretical calculations, the star SDSS J142625.71 + 575218.3 is the only object expected to pulsate. We observe this star to be variable, with significant power at 417.7 s and 208.8 s ( first harmonic), making it a strong candidate as the first member of a new class of pulsating white dwarf stars, the DQVs. Its folded pulse shape, however, is quite different from that of other white dwarf variables and shows similarities with that of the cataclysmic variable AM CVn, raising the possibility that this star may be a carbon-transferring analog of AM CVn stars. In either case, these observations represent the discovery of a new and exciting class of object.NSF AST-0507639, AST-0602288, AST-0607480, AST-0307321Astronom

Investigating five key predictive text entry with combined distance and keystroke modelling

This paper investigates text entry on mobile devices using only five-keys. Primarily to support text entry on smaller devices than mobile phones, this method can also be used to maximise screen space on mobile phones. Reported combined Fitt's law and keystroke modelling predicts similar performance with bigram prediction using a five-key keypad as is currently achieved on standard mobile phones using unigram prediction. User studies reported here show similar user performance on five-key pads as found elsewhere for novice nine-key pad users

The impact of co-located NHS walk-in centres on emergency departments

Objectives: To determine the impact of establishing walk-in centres alongside emergency departments on attendance rates, visit duration, process, costs and outcome of care. Methods: Eight hospitals with co-located emergency departments and walk-in centres were compared with eight matched emergency departments without walk-in centres. Site visits were conducted. Routine data about attendance numbers and use of resources were analysed. A random sample of records of patients attending before and after walk-in centres opened were also assessed. Patients who had not been admitted to hospital were sent a postal questionnaire. Results: In most sites, the walk-in centres did not have a distinct identity and there were few differences in the way services were provided compared with control sites. Overall, there was no evidence of an increase in attendance at sites with walk-in centres, but considerable variability across sites. The proportion of patients managed within the four-hour NHS target improved at sites both with and without walk-in centres. There was no evidence of any difference in re-consultation rates, costs of care or patient outcomes at sites with or without walk-in centres. Conclusions: Most hospitals in this study implemented the walk-in centre concept to a very limited extent. Consequently there was no evidence of any impact on attendance rates, process, costs or outcome of care

Comparing care at walk-in centres and at accident and emergency departments: an exploration of patient choice, preference and satisfaction

Objectives: To explore the impact of establishing walk-in centres alongside emergency departments on patient choice, preference and satisfaction. Methods: A controlled, mixed-method study comparing eight emergency departments with co-located walk-in centres with the same number of ‘traditional’ emergency departments. This paper focuses on the results of a cross-sectional questionnaire survey of users. Results: Survey data demonstrated that patients were frequently unable to distinguish between being treated at a walk-in centre or an A&E department, and even where this was the case, opportunities to exercise choice about their preferred care provider were often limited. Few made an active choice to attend a co-located walk-in centre. Patients attending walk-in centres were just as likely to be satisfied overall with the care they received as their counterparts who were treated in the co-located A&E facility, although a small proportion of walk-in centre users did report greater satisfaction with some specific aspects of their care and consultation. Conclusions: Whilst one of the key policy goals underpinning the co-location of walk-in centres next to an A&E department was to provide patients with more options for accessing healthcare and greater choice, leading in turn to increased satisfaction, this evaluation was able to provide little evidence to support this. The high percentage of patients expressing a preference for care in an established emergency department compared to a new walk-in centre facility raises questions for future policy development. Further consideration should therefore be given to the role that A&E focused walk-in centres play in the Department of Health’s current policy agenda, as far as patient choice is concerned

A Comparison of the Storage-Only Deficit and Joint Mechanism Deficit Hypotheses of the Verbal Working Memory Storage Capacity Limitation of Children with Developmental Language Disorder

Purpose: The storage-only deficit and joint mechanism deficit hypotheses are two possible explanations of the verbal working memory (vWM) storage capacity limitation of school-age children with developmental language disorder (DLD). We assessed the merits of each hypothesis in a large group of children with DLD and a group of same-age typically developing (TD) children. Method: Participants were 117 children with DLD and 117 propensity-matched TD children 7-11 years of age. Children completed tasks indexing vWM capacity, verbal short-term storage, sustained attention, attention switching, and lexical long-term memory (LTM). Results: For the DLD group, all of the mechanisms jointly explained 26.5% of total variance. Storage accounted for the greatest portion (13.7%), followed by controlled attention (primarily sustained attention 6.5%), and then lexical LTM (5.6%). For the TD group, all three mechanisms together explained 43.9% of total variance. Storage accounted for the most variance (19.6%), followed by lexical LTM (16.0%), sustained attention (5.4%), and attention switching (3.0%). There was a significant LTM by Group interaction in which stronger LTM scores were associated with significantly higher vWM capacity scores for the TD group as compared to the DLD group. Conclusions: Results support a joint mechanism deficit account of the vWM capacity limitation of children with DLD. Results provide substantively new insights into the underlying factors of the vWM capacity limitation in DLD

The dryas iulia genome supports multiple gains of a W chromosome from a B chromosome in butterflies

In butterflies and moths, which exhibit highly variable sex determination mechanisms, the homogametic Z chromosome is deeply conserved and is featured in many genome assemblies. The evolution and origin of the female W sex chromosome, however, remains mostly unknown. Previous studies have proposed that a ZZ/Z0 sex determination system is ancestral to Lepidoptera, and that W chromosomes may originate from sex-linked B chromosomes. Here, we sequence and assemble the female Dryas iulia genome into 32 highly contiguous ordered and oriented chromosomes, including the Z and W sex chromosomes. We then use sex-specific Hi-C, ATAC-seq, PRO-seq, and whole-genome DNA sequence data sets to test if features of the D. iulia W chromosome are consistent with a hypothesized B chromosome origin. We show that the putative W chromosome displays female-associated DNA sequence, gene expression, and chromatin accessibility to confirm the sex-linked function of the W sequence. In contrast with expectations from studies of homologous sex chromosomes, highly repetitive DNA content on the W chromosome, the sole presence of domesticated repetitive elements in functional DNA, and lack of sequence homology with the Z chromosome or autosomes is most consistent with a B chromosome origin for the W, although it remains challenging to rule out extensive sequence divergence. Synteny analysis of the D. iulia W chromosome with other female lepidopteran genome assemblies shows no homology between W chromosomes and suggests multiple, independent origins of the W chromosome from a B chromosome likely occurred in butterflies

Night feeding to reduce bird predation in feedlots

During times of heavy infestations by birds, feedlots can have 25 to 30% increases in feed usage, thereby resulting in large economic losses. Because starlings, blackbirds, grackles, and other avian pests normally feed during daylight hours, we hypothesized that feeding cattle at night would minimize feed contamination and feed loss due to bird infestation. Crossbred beef heifers (n=96; 770 lb) were used to evaluate the effects of feeding at night on performance and carcass characteristics. Heifers were fed for 107 days during the months of November to March, when large bird populations were observed. Feed was delivered once daily at approximately 10:00 a.m. for heifers with continuous access to feed and 30 minutes before dusk for heifers that had access to feed only at night. Feed calls for heifers fed at night were managed so that no feed remained in the bunk at dawn, whereas the control heifers were allowed ad libitum access to feed. Daily feed deliveries per animal (21.51 vs. 18.15 lb for heifers fed continuously or only at night, respectively) were decreased by 16% (P<0.01) when cattle were provided access to feed only at night, but daily gain was not different. Feed efficiency was improved by 14% (P=0.05) with night time feeding, but carcass weights and dressing percentage remained similar. Overall, feeding cattle only during hours of darkness yielded similar growth performance compared to cattle fed continuously. However, feed efficiency was improved substantially, which we attribute to reduced theft by birds

Does Access to Health Care Impact Survival Time after Diagnosis of AIDS?

Lack of access to health care is often blamed for poor health outcomes, but this effect is not supported by existing HIV/AIDS literature. The authors examined the association between access to care and survival time after progression to AIDS, using survival analysis methods. This study combined data from two CDC sponsored studies of HIV-infected persons, a cross-sectional interview study and a longitudinal medical record review study. Study subjects included 752 persons who progressed to AIDS before December 31, 1999, and were patients at either of two major HIV care facilities in Detroit, MIchigan. Separate statistical models were used to test associations between survival time after meeting the criteria for AIDS and two indicators of access to health care: (1) perceived access to health care and (2) health care utilization patterns. Perceived access was not associated with survival time after AIDS, but patterns of health care utilization were significantly associated with survival time after AIDS (HR = 2.04, p < 0.001). Individuals who received a greater proportion of their care in the ER had a worse survival prognosis than those who received more of their health care in an outpatient clinic setting. It is crucial that we provide HIV-infected populations with tools that enable them to access a regular source of health care.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63272/1/10872910252972276.pd

Chromosome fusion affects genetic diversity and evolutionary turnover of functional loci, but consistently depends on chromosome size

Major changes in chromosome number and structure are linked to a series of evolutionary phenomena, including intrinsic barriers to gene flow or suppression of recombination due to chromosomal rearrangements. However, chromosome rearrangements can also affect the fundamental dynamics of molecular evolution within populations by changing relationships between linked loci and altering rates of recombination. Here, we build chromosome-level assembly Eueides isabella and, together with a recent chromosome-level assembly of Dryas iulia, examine the evolutionary consequences of multiple chromosome fusions in Heliconius butterflies. These assemblies pinpoint fusion points on 10 of the 20 autosomal chromosomes and reveal striking differences in the characteristics of fused and unfused chromosomes. The ten smallest autosomes in D. iulia and E. isabella, which have each fused to a longer chromosome in Heliconius, have higher repeat and GC content, and longer introns than predicted by their chromosome length. When fused, these characteristics change to become more in line with chromosome length. The fusions also led to reduced diversity, which likely reflects increased background selection and selection against introgression between diverging populations, following a reduction in per-base recombination rate. We further show that chromosome size and fusion impact turnover rates of functional loci at a macroevolutionary scale. Together these results provide further evidence that chromosome fusion in Heliconius likely had dramatic effects on population level processes shaping rates of neutral and adaptive divergence. These effects may have impacted patterns of diversification in Heliconius, a classic example of an adaptive radiation

Smoothed Particle Hydrodynamics Simulations of Apsidal and Nodal Superhumps

In recent years a handful of systems have been observed to show "negative" (nodal) superhumps, with periods slightly shorter than the orbital period. It has been suggested that these modes are a consequence of the slow retrograde precession of the line of nodes in a disk tilted with respect to the orbital plane. Our simulations confirm and refine this model: they suggest a roughly axisymmetric, retrogradely-precessing, tilted disk that is driven at a period slightly less than half the orbital period as the tidal field of the orbiting secondary encounters in turn the two halves of the disk above and below the midplane. Each of these passings leads to viscous dissipation on one face of an optically-thick disk -- observers on opposite sides of the disk would each observe one brightening per orbit, but 180 degrees out of phase with each other.Comment: 11 pages. Accepted for publication in The ApJ Letter