Spatial Grain Size Sorting in Eolian Ripples and Estimation of Wind Conditions on Planetary Surfaces: Application to Meridiani Planum, Mars

The landscape seen by the Mars Exploration Rover (MER) Opportunity at Meridiani Planum is dominated by eolian (wind-blown) ripples with concentrated surface lags of hematitic spherules and fragments. These ripples exhibit profound spatial grain size sorting, with well-sorted coarse-grained crests and poorly sorted, generally finer-grained troughs. These ripples were the most common bed form encountered by Opportunity in its traverse from Eagle Crater to Endurance Crater. Field measurements from White Sands National Monument, New Mexico, show that such coarse-grained ripples form by the different transport modes of coarse- and fine-grain fractions. On the basis of our field study, and simple theoretical and experimental considerations, we show how surface deposits of coarse-grained ripples can be used to place tight constraints on formative wind conditions on planetary surfaces. Activation of Meridiani Planum coarse-grained ripples requires a wind velocity of 70 m/s (at a reference elevation of 1 m above the bed). From images by the Mars Orbiter Camera (MOC) of reversing dust streaks, we estimate that modern surface winds reach a velocity of at least 40 m/s and hence may occasionally activate these ripples. The presence of hematite at Meridiani Planum is ultimately related to formation of concretions during aqueous diagenesis in groundwater environments; however, the eolian concentration of these durable particles may have led to the recognition from orbit of this environmentally significant landing site

How does cholecystectomy influence recurrence of idiopathic acute pancreatitis?

BackgroundIdiopathic acute pancreatitis is diagnosed in approximately 10–30 % of cases of acute pancreatitis. While there is evidence to suggest that the cause in many of these patients is microlithiasis, this fact has not been translated into a resource efficient treatment strategy that is proven to reduce recurrence rates. The aim of this study was to examine the value of prophylactic cholecystectomy following an episode of acute pancreatitis in patients with no history of alcohol abuse and no stones found on ultrasound.MethodsThis was a retrospective study of 2236 patients who presented to a regional Australian hospital. Patients were included when diagnosed with acute pancreatitis with no confirmed cause. Recurrence of acute pancreatitis was compared between those that did and did not undergo cholecystectomy.ResultsOne hundred ninety-five consecutive patients met the study definition of “idiopathic” acute pancreatitis. 33.8 % (66/195) underwent cholecystectomy. The patients who had cholecystectomy had a recurrence rate of 19.7 % (13/66) whereas, of those managed expectantly, 42.8 % (68/159) had at least one recurrence of acute pancreatitis (P = 0.001).ConclusionsFollowing an episode of acute pancreatitis with no identifiable cause, in patients fit for surgery, cholecystectomy should be considered to reduce the risk of recurrent episodes of pancreatitis

Migration experiences, employment status and psychological distress among Somali immigrants: a mixed-method international study

Background: The discourse about mental health problems among migrants and refugees tends to focus on adverse pre-migration experiences; there is less investigation of the environmental conditions in which refugee migrants live, and the contrasts between these situations in different countries. This cross-national study of two samples of Somali refugees living in London (UK) and Minneapolis, Minnesota, (USA) helps to fill a gap in the literature, and is unusual in being able to compare information collected in the same way in two cities in different countries. Methods: There were two parts to the study, focus groups to gather in-depth qualitative data and a survey of health status and quantifiable demographic and material factors. Three of the focus groups involved nineteen Somali professionals and five groups included twenty-eight lay Somalis who were living in London and Minneapolis. The quantitative survey was done with 189 Somali respondents, also living in London and Minneapolis. We used the MINI International Neuropsychiatric Interview (MINI) to assess ICD-10 and Results: The overall qualitative and quantitative results suggested that challenges to masculinity, thwarted aspirations, devalued refugee identity, unemployment, legal uncertainties and longer duration of stay in the host country account for poor psychological well-being and psychiatric disorders among this group. Conclusion: The use of a mixed-methods approach in this international study was essential since the quantitative and qualitative data provide different layers and depth of meaning and complement each other to provide a fuller picture of complex and multi-faceted life situations of refugees and asylum seekers. The comparison between the UK and US suggests that greater flexibility of access to labour markets for this refugee group might help to promote opportunities for better integration and mental well-being

Alinhamento interpessoal, representacional e morfossintático na Gramática Discursivo-Funcional

Este artigo se debruça sobre o mapeamento entre os Níveis Interpessoal, Representacional e Morfossintático da gramática, o chamado alinhamento, segundo o arcabouço da Gramática Discursivo-Funcional (GDF). Propõe uma tipologia das línguas baseada no que a sua organização morfossintática codifica: distinções pragmáticas (p.ex. em Tagalo), distinções semânticas (p.ex. em Achém), ou distinções inerentes à morfossintaxe (p.ex. em Inglês, Basco ou a língua Kham). A inclusão tanto do Sujeito como do Objeto e de línguas tanto acusativas como ergativas no tratamento do alinhamento morfossintático permitiu-nos abranger tipos tipologicamente mais variáveis e demonstrar o potencial da GDF para a análise contrastiva das línguas.<br>Within the framework of Functional Discourse Grammar (FDG), alignment concerns the relations between the Interpersonal, Representational and Morphosyntactic Levels of grammar. This article proposes a typology of languages based upon what we find to be encoded in their morphosyntactic organization: pragmatic distinctions (as in Tagalog), semantic distinctions (as in Acheh), or distinctions inherent to the morphosyntax (as in English, Basque and Kham). By including both subject and object, and both accusative and ergative languages in our treatment of morphosyntactic alignment, we provide a better coverage of typological variation and show the potential of FDG for cross-linguistic analysis

Emergency and critical care services in Tanzania: a survey of ten hospitals.

While there is a need for good quality care for patients with serious reversible disease in all countries in the world, Emergency and Critical Care tends to be one of the weakest parts of health systems in low-income countries. We assessed the structure and availability of resources for Emergency and Critical Care in Tanzania in order to identify the priorities for improving care in this neglected specialty. Ten hospitals in four regions of Tanzania were assessed using a structured data collection tool. Quality was evaluated with standards developed from the literature and expert opinion. Important deficits were identified in infrastructure, routines and training. Only 30% of the hospitals had an emergency room for adult and paediatric patients. None of the seven district and regional hospitals had a triage area or intensive care unit for adults. Only 40% of the hospitals had formal systems for adult triage and in less than one third were critically ill patients seen by clinicians more than once daily. In 80% of the hospitals there were no staff trained in adult triage or critical care. In contrast, a majority of equipment and drugs necessary for emergency and critical care were available in the hospitals (median 90% and 100% respectively. The referral/private hospitals tended to have a greater overall availability of resources (median 89.7%) than district/regional hospitals (median 70.6). Many of the structures necessary for Emergency and Critical Care are lacking in hospitals in Tanzania. Particular weaknesses are infrastructure, routines and training, whereas the availability of drugs and equipment is generally good. Policies to improve hospital systems for the care of emergency and critically ill patients should be prioritised

Does a SLAP lesion affect shoulder muscle recruitment as measured by EMG activity during a rugby tackle?

Background: The study objective was to assess the influence of a SLAP lesion on onset of EMG activity in shoulder muscles during a front on rugby football tackle within professional rugby players. Methods: Mixed cross-sectional study evaluating between and within group differences in EMG onset times. Testing was carried out within the physiotherapy department of a university sports medicine clinic. The test group consisted of 7 players with clinically diagnosed SLAP lesions, later verified on arthroscopy. The reference group consisted of 15 uninjured and full time professional rugby players from within the same playing squad. Controlled tackles were performed against a tackle dummy. Onset of EMG activity was assessed from surface EMG of Pectorialis Major, Biceps Brachii, Latissimus Dorsi, Serratus Anterior and Infraspinatus muscles relative to time of impact. Analysis of differences in activation timing between muscles and limbs (injured versus non-injured side and non injured side versus matched reference group). Results: Serratus Anterior was activated prior to all other muscles in all (P = 0.001-0.03) subjects. In the SLAP injured shoulder Biceps was activated later than in the non-injured side. Onset times of all muscles of the noninjured shoulder in the injured player were consistently earlier compared with the reference group. Whereas, within the injured shoulder, all muscle activation timings were later than in the reference group. Conclusions: This study shows that in shoulders with a SLAP lesion there is a trend towards delay in activation time of Biceps and other muscles with the exception of an associated earlier onset of activation of Serratus anterior, possibly due to a coping strategy to protect glenohumeral stability and thoraco-scapular stability. This trend was not statistically significant in all cases

First-Year Spectroscopy for the SDSS-II Supernova Survey

This paper presents spectroscopy of supernovae discovered in the first season of the Sloan Digital Sky Survey-II Supernova Survey. This program searches for and measures multi-band light curves of supernovae in the redshift range z = 0.05 - 0.4, complementing existing surveys at lower and higher redshifts. Our goal is to better characterize the supernova population, with a particular focus on SNe Ia, improving their utility as cosmological distance indicators and as probes of dark energy. Our supernova spectroscopy program features rapid-response observations using telescopes of a range of apertures, and provides confirmation of the supernova and host-galaxy types as well as precise redshifts. We describe here the target identification and prioritization, data reduction, redshift measurement, and classification of 129 SNe Ia, 16 spectroscopically probable SNe Ia, 7 SNe Ib/c, and 11 SNe II from the first season. We also describe our efforts to measure and remove the substantial host galaxy contamination existing in the majority of our SN spectra.Comment: Accepted for publication in The Astronomical Journal(47pages, 9 figures

Explosive volcanism in complex impact craters on Mercury and the Moon: influence of tectonic regime on depth of magmatic intrusion

Vents and deposits attributed to explosive volcanism occur within numerous impact craters on both the Moon and Mercury. Given the similarities between the two bodies it is probable that similar processes control this spatial association on both. However, the precise morphology and localization of the activity differs on the two bodies, indicating that the nature of structures beneath impact craters and/or volcanic activity may also be different. To explore this, we analyze sites of explosive volcanism within complex impact craters on the Moon and Mercury, comparing the scale and localization of volcanic activity and evidence for post-formation modification of the host crater. We show that the scale of vents and deposits is consistently greater on Mercury than on the Moon, indicating greater eruption energy, powered by a higher concentration of volatiles. Additionally, while the floors of lunar craters hosting explosive volcanism are commonly fractured, those on Mercury are not. The most probable explanation for these differences is that the state of regional compression acting on Mercury's crust through most of the planet's history results in deeper magma storage beneath craters on Mercury than on the Moon. The probable role of the regional stress regime in dictating the depth of intrusion on Mercury suggests that it may also play a role in the depth of sub-crater intrusion on the Moon and on other planetary bodies. Examples on the Moon (and also on Mars) commonly occur at locations where flexural extension may facilitate shallower intrusion than would be driven by the buoyancy of the magma alone