Task Attention Facilitates Learning of Task-Irrelevant Stimuli

Attention plays a fundamental role in visual learning and memory. One highly established principle of visual attention is that the harder a central task is, the more attentional resources are used to perform the task and the smaller amount of attention is allocated to peripheral processing because of limited attention capacity. Here we show that this principle holds true in a dual-task setting but not in a paradigm of task-irrelevant perceptual learning. In Experiment 1, eight participants were asked to identify either bright or dim number targets at the screen center and to remember concurrently presented scene backgrounds. Their recognition performances for scenes paired with dim/hard targets were worse than those for scenes paired with bright/easy targets. In Experiment 2, eight participants were asked to identify either bright or dim letter targets at the screen center while a task-irrelevant coherent motion was concurrently presented in the background. After five days of training on letter identification, participants improved their motion sensitivity to the direction paired with hard/dim targets improved but not to the direction paired with easy/bright targets. Taken together, these results suggest that task-irrelevant stimuli are not subject to the attentional control mechanisms that task-relevant stimuli abide

A prospective study of decline in fat free mass and skeletal muscle strength in chronic obstructive pulmonary disease

BACKGROUND: Skeletal muscle depletion is an important complication of chronic obstructive pulmonary disease (COPD) but little prospective data exists about the rate at which it occurs and the factors that promote its development. We therefore prospectively investigated the impact of disease severity, exacerbation frequency and treatment with corticosteroids on change in body composition and maximum isometric quadriceps strength (QMVC) over one year. METHODS: 64 patients with stable COPD (FEV(1 )mean (SD) 35.8(18.4) %predicted) were recruited from clinic and studied on two occasions one year apart. Fat free mass was determined using bioelectrical impedance analysis and a disease specific regression equation. RESULTS: QMVC fell from 34.8(1.5) kg to 33.3(1.5) kg (p = 0.04). The decline in quadriceps strength was greatest in those with the highest strength at baseline (R -0.28 p = 0.02) and was not correlated with lung function, exacerbation frequency or steroid treatment. Decline in fat free mass was similarly higher in those with largest FFM at baseline (R = -0.31 p = 0.01) but was more strongly correlated with greater gas trapping (R = -0.4 p = 0.001). Patients with frequent exacerbations (>1 per year) (n = 36) experienced a greater decline in fat free mass compared to infrequent exacerbators (n = 28) -1.3(3.7)kg vs. +1.2(3.1)kg (p = 0.005), as did patients on maintenance oral steroids (n = 8) -2.8(3.3) kg vs. +0.2(3.5) kg (p = 0.024) whereas in those who stopped smoking (n = 7) fat free mass increased; +2.7(3.1) kg vs. -0.51(3.5) kg (p = 0.026). CONCLUSION: Decline in fat free mass in COPD is associated with worse lung function, continued cigarette consumption and frequent exacerbations. Factors predicting progression of quadriceps weakness could not be identified from the present cohort

Contrasting patterns of evolutionary constraint and novelty revealed by comparative sperm proteomic analysis in Lepidoptera

Background: Rapid evolution is a hallmark of reproductive genetic systems and arises through the combined processes of sequence divergence, gene gain and loss, and changes in gene and protein expression. While studies aiming to disentangle the molecular ramifications of these processes are progressing, we still know little about the genetic basis of evolutionary transitions in reproductive systems. Here we conduct the first comparative analysis of sperm proteomes in Lepidoptera, a group that exhibits dichotomous spermatogenesis, in which males produce a functional fertilization-competent sperm (eupyrene) and an incompetent sperm morph lacking nuclear DNA (apyrene). Through the integrated application of evolutionary proteomics and genomics, we characterize the genomic patterns potentially associated with the origination and evolution of this unique spermatogenic process and assess the importance of genetic novelty in Lepidopteran sperm biology. Results: Comparison of the newly characterized Monarch butterfly (Danaus plexippus) sperm proteome to those of the Carolina sphinx moth (Manduca sexta) and the fruit fly (Drosophila melanogaster) demonstrated conservation at the level of protein abundance and post-translational modification within Lepidoptera. In contrast, comparative genomic analyses across insects reveals significant divergence at two levels that differentiate the genetic architecture of sperm in Lepidoptera from other insects. First, a significant reduction in orthology among Monarch sperm genes relative to the remainder of the genome in non-Lepidopteran insect species was observed. Second, a substantial number of sperm proteins were found to be specific to Lepidoptera, in that they lack detectable homology to the genomes of more distantly related insects. Lastly, the functional importance of Lepidoptera specific sperm proteins is broadly supported by their increased abundance relative to proteins conserved across insects. Conclusions: Our results identify a burst of genetic novelty amongst sperm proteins that may be associated with the origin of heteromorphic spermatogenesis in ancestral Lepidoptera and/or the subsequent evolution of this system. This pattern of genomic diversification is distinct from the remainder of the genome and thus suggests that this transition has had a marked impact on lepidopteran genome evolution. The identification of abundant sperm proteins unique to Lepidoptera, including proteins distinct between specific lineages, will accelerate future functional studies aiming to understand the developmental origin of dichotomous spermatogenesis and the functional diversification of the fertilization incompetent apyrene sperm morph

Frequency of macroscopic intradural hemorrhage with and without subdural hemorrhage in early childhood autopsies.

Some authors have suggested that in the fetus, neonate and infant, intradural hemorrhage (IDH) is relatively common and often presents alongside subdural hemorrhage (SDH). These authors have theorized that pediatric SDH may result from an IDH due to blood leakage from a dural vascular plexus. In this study, we report the inter-observer variation for detection of IDH from a retrospectively collected series of pediatric autopsy photographs, with and without SDH. Autopsy photographs of the falx and tentorium from 27 neonatal, infant and early childhood autopsies were assessed by two independent consultant forensic pathologists blinded to all case histories for the presence and extent (focal or diffuse) of IDH. Inter-observer agreement between the pathologists was calculated using Cohen's kappa coefficient. The occurrence of subdural hemorrhage was also recorded at autopsy. A kappa coefficient value of 0.669 (p = 0.001), indicated a substantial level of agreement for the presence/absence of IDH between the pathologists. For the extent of IDH a kappa coefficient value of 0.6 (p = 0.038) indicated a moderate level of agreement. The pathologists agreed on the presence of IDH in 10 of the 27 cases. Subdural hemorrhage was recorded for 8 out of 27 cases. Of these 8 cases, it was agreed that 4 had IDH. Using standardized methods of image capture and assessment, inter-observer agreement for the presence/absence of IDH was substantial. In this paper, we report a much lower frequency of macroscopic IDH occurring alongside SDH than previous studies, which included both gross observation of IDH and histological examination

Born in Bradford, a cohort study of babies born in Bradford, and their parents: protocol for the recruitment phase

BACKGROUND: Bradford, one of the most deprived cities in the United Kingdom, has a wide range of public health problems associated with socioeconomic deprivation, including an infant mortality rate almost double that for England and Wales. Infant mortality is highest for babies of Pakistani origin, who comprise almost half the babies born in Bradford. The Born in Bradford cohort study aims to examine environmental, psychological and genetic factors that impact on health and development perinatally, during childhood and subsequent adult life, and those that influence their parents' health and wellbeing. This protocol outlines methods for the recruitment phase of the study. METHODS: Most Bradford women attend for antenatal care and give birth at the Bradford Royal Infirmary, which has approximately 5,800 births per year. Women are eligible for recruitment if they plan to give birth here. Babies born from March 2007 are eligible to participate, recruitment is planned to continue until 2010. Fathers of babies recruited are invited to participate. Women are usually recruited when they attend for a routine oral glucose tolerance test at 26-28 weeks gestation. Recruitment of babies is at birth. Fathers are recruited whenever possible during the antenatal period, or soon after the birth. The aim is to recruit 10,000 women, their babies, and the babies' fathers. At recruitment women have blood samples taken, are interviewed to complete a semi-structured questionnaire, weighed, and have height, arm circumference and triceps skinfold measured. Umbilical cord blood is collected at birth. Within two weeks of birth babies have their head, arm and abdominal circumference measured, along with subscapular and triceps skinfold thickness. Fathers self-complete a questionnaire at recruitment, have height and weight measured, and provide a saliva sample. Participants are allocated a unique study number. NHS numbers will be used to facilitate record linkage and access to routine data. A wide range of hospital and community sources is being accessed to provide data for the women and children. Data are checked for accuracy and consistency. CONCLUSION: Born in Bradford will increase understanding of the factors that contribute to health and wellbeing, and identify factors that influence differences in them between people of Pakistani and European origin