From z>6 to z~2: Unearthing Galaxies at the Edge of the Dark Ages

Galaxies undergoing formation and evolution can now be observed over a time baseline of some 12 Gyr. An inherent difficulty with high-redshift observations is that the objects are very faint and the best resolution (HST) is only ~0.5 kpc. Such studies thereby combine in a highly synergistic way with the great detail that can be obtained for nearby galaxies. 3 new developments are highlighted. First is the derivation of stellar masses for galaxies from SEDs using HST and now Spitzer data, and dynamical masses from both sub-mm observations of CO lines and near-IR observations of optical lines like Halpha. A major step has been taken with evidence that points to the z~2-3 LBGs having masses that are a few x 10^10 Msolar. Second is the discovery of a population of evolved red galaxies at z~2-3 which appear to be the progenitors of the more massive early-type galaxies of today, with dynamical masses around a few x 10^11 Msolar. Third are the remarkable advances that have occurred in characterizing dropout galaxies to z~6 and beyond, < 1 Gyr from recombination. The HST ACS has played a key role here, with the dropout technique being applied to i & z images in several deep ACS fields, yielding large samples of these objects. This has allowed a detailed determination of their properties and meaningful comparisons against lower-z samples. The use of cloning techniques has overcome many of the strong selection biases affecting the study of these objects. A clear trend of size with redshift has been identified, and its impact on the luminosity density and SFR estimated. There is a significant though modest decrease in the SFR from z~2.5 to z~6. The latest data also allow for the first robust determination of the LF at z~6. Finally, the latest UDF ACS and NICMOS data has resulted in the detection of some galaxies at z~7-8.Comment: 18 pages, 8 figures. To appear in Penetrating Bars through Masks of Cosmic Dust: The Hubble Tuning Fork Strikes a New Note, eds. D. Block, K. Freeman, R. Groess, I. Puerari, & E.K. Block (Dordrecht: Kluwer), in pres

Heterochronic faecal transplantation boosts gut germinal centres in aged mice

Ageing is a complex multifactorial process associated with a plethora of disorders, which contribute significantly to morbidity worldwide. One of the organs significantly affected by age is the gut. Age-dependent changes of the gut-associated microbiome have been linked to increased frailty and systemic inflammation. This change in microbial composition with age occurs in parallel with a decline in function of the gut immune system, however it is not clear if there is a causal link between the two. Here we report that the defective germinal centre reaction in Peyer’s patches of aged mice can be rescued by faecal transfers from younger adults into aged mice and by immunisations with cholera toxin, without affecting germinal centre reactions in peripheral lymph nodes. This demonstrates that the poor germinal centre reaction in aged animals is not irreversible, and that it is possible to improve this response in older individuals by providing appropriate stimuli

Bmi-1 dependence distinguishes neural stem cell self-renewal from progenitor proliferation

Stem cells persist throughout life by self-renewing in numerous tissues including the central(1) and peripheral(2) nervous systems. This raises the issue of whether there is a conserved mechanism to effect self-renewing divisions. Deficiency in the polycomb family transcriptional repressor Bmi-1 leads to progressive postnatal growth retardation and neurological defects(3). Here we show that Bmi-1 is required for the self-renewal of stem cells in the peripheral and central nervous systems but not for their survival or differentiation. The reduced self-renewal of Bmi-1-deficient neural stem cells leads to their postnatal depletion. In the absence of Bmi-1, the cyclin-dependent kinase inhibitor gene p16(Ink4a) is upregulated in neural stem cells, reducing the rate of proliferation. p16(Ink4a) deficiency partially reverses the self-renewal defect in Bmi-1(-/-) neural stem cells. This conserved requirement for Bmi-1 to promote self-renewal and to repress p16(Ink4a) expression suggests that a common mechanism regulates the self-renewal and postnatal persistence of diverse types of stem cell. Restricted neural progenitors from the gut and forebrain proliferate normally in the absence of Bmi-1. Thus, Bmi-1 dependence distinguishes stem cell self-renewal from restricted progenitor proliferation in these tissues.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62726/1/nature02060.pd

Psychosocial factors during the first year after a coronary heart disease event in cases and referents. Secondary Prevention in Uppsala Primary Health Care Project (SUPRIM)

<p>Abstract</p> <p>Background</p> <p>A large number of studies have reported on the psychosocial risk factor pattern prior to coronary heart disease events, but few have investigated the situation during the first year after an event, and none has been controlled. We therefore performed a case-referent study in which the prevalence of a number of psychosocial factors was evaluated.</p> <p>Methods</p> <p>Three hundred and forty-six coronary heart disease male and female cases no more than 75 years of age, discharged from hospital within the past 12 months, and 1038 referents from the general population, matched to the cases by age, sex and place of living, received a postal questionnaire in which information on lifestyle, psychosocial and quality of life measures were sought.</p> <p>Results</p> <p>The cases were, as expected, on sick leave to a larger extent than the referents, reported poorer fitness, poorer perceived health, fewer leisure time activities, but unexpectedly reported better social support, and more optimistic views of the future than the referents. There were no significant case-referent differences in everyday life stress, stressful life events, vital exhaustion, depressive mood, coping or life orientation test. However, women reported less favourable situations than men regarding stressful life events affecting others, vital exhaustion, depressive mood, coping, self-esteem, sleep, and symptom reporting, and female cases reported the most unfavourable situation of all groups.</p> <p>Conclusion</p> <p>In this first controlled study of the situation during the first year after a CHD event disease and gender status both appeared to be determinants of psychological well-being, with gender status apparently the strongest. This may have implications for cardiac rehabilitation programmes.</p

Living Alone, Patient Sex and Mortality After Acute Myocardial Infarction

BACKGROUND: Psychosocial factors, including social support, affect outcomes of cardiovascular disease, but can be difficult to measure. Whether these factors have different effects on mortality post-acute myocardial infarction (AMI) in men and women is not clear. OBJECTIVE: To examine the association between living alone, a proxy for social support, and mortality postdischarge AMI and to explore whether this association is modified by patient sex. DESIGN: Historical cohort study. PARTICIPANTS/SETTING: All patients discharged with a primary diagnosis of AMI in a major urban center during the 1998–1999 fiscal year. MEASUREMENTS: Patients’ sociodemographic and clinical characteristics were obtained by standardized chart review and linked to vital statistics data through December 2001. RESULTS: Of 880 patients, 164 (18.6%) were living alone at admission and they were significantly more likely to be older and female than those living with others. Living alone was independently associated with mortality [adjusted hazard ratio (HR) 1.6, 95% confidence interval (CI) 1.0–2.5], but interacted with patient sex. Men living alone had the highest mortality risk (adjusted HR 2.0, 95% CI 1.1–3.7), followed by women living alone (adjusted HR 1.2, 95% CI 0.7–2.2), men living with others (reference, HR 1.0), and women living with others (adjusted HR 0.9, 95% CI 0.5–1.5). CONCLUSIONS: Living alone, an easily measured psychosocial factor, is associated with significantly increased longer-term mortality for men following AMI. Further prospective studies are needed to confirm the usefulness of living alone as a prognostic factor and to identify the potentially modifiable mechanisms underlying this increased risk

Effects and predictors of shoulder muscle massage for patients with posterior shoulder tightness

Background: Clinical approaches like mobilization, stretching, and/or massage may decrease shoulder tightness and improve symptoms in subjects with stiff shoulders. We investigated the effect and predictors of effectiveness of massage in the treatment of patients with posterior shoulder tightness. ;Methods: A randomized controlled trial was conducted in a hospital-based outpatient practice (orthopedic and rehabilitation). Forty-three women and 17 men (mean age = 54 years, range 43-73 years) with posterior shoulder tightness participated and were randomized into massage and control groups (n = 30 per group). A physical therapist provided the massage on the posterior deltoid, infraspinatus, and teres minor of the involved shoulder for 18 minutes [about 6 minutes for each muscle] two times a week for 4 weeks. For the control group, one therapist applied light hand touch on the muscles 10 minutes two times a week for 4 weeks. Glenohumeral internal rotation ROM, functional status, and muscle tightness were the main outcomes. Additionally, the potential factors on the effectiveness of massage were analyzed by multivariate logistic regression. For this analysis, patients with functional score improvement at least 20% after massage were considered responsive, and the others were considered nonresponsive. ;Results: Fifty-two patients completed the study (29 for the massage and 23 for the control). The overall mean internal rotation ROM increased significantly in the massage group compared to the control (54.9 degrees v.s. 34.9 degrees; P &lt;= 0.001). There were 21 patients in the responsive group and 8 in the nonresponsive group. Among the factors, duration of symptoms, functional score, and posterior deltoid tightness were significant predictors of effectiveness of massage. ;Conclusions: Massage was an effective treatment for patients with posterior shoulder tightness, but was less effective in patients with longer duration of symptoms, higher functional limitation, and less posterior deltoid tightness

Hydrodynamics of fossil fishes

Fromtheir earliest origins, fishes have developed a suite of adaptations for locomotion in water, which determine performance and ultimately fitness. Even without data from behaviour, soft tissue and extant relatives, it is possible to infer a wealth of palaeobiological and palaeoecological information. As in extant species, aspects of gross morphology such as streamlining, fin position and tail type are optimized even in the earliest fishes, indicating similar life strategies have been present throughout their evolutionary history. As hydrodynamical studies become more sophisticated, increasingly complex fluid movement can be modelled, including vortex formation and boundary layer control. Drag-reducing riblets ornamenting the scales of fast-moving sharks have been subjected to particularly intense research, but this has not been extended to extinct forms. Riblets are a convergent adaptation seen in many Palaeozoic fishes, and probably served a similar hydrodynamic purpose. Conversely, structures which appear to increase skin friction may act as turbulisors, reducing overall dragwhile serving a protective function. Here,we examine the diverse adaptions that contribute to drag reduction in modern fishes and review the few attempts to elucidate the hydrodynamics of extinct forms

TRY plant trait database - enhanced coverage and open access

Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives