Evolutionary Signatures In The Formation Of Low-Mass Protostars. II. Toward Reconciling Models And Observations

A long-standing problem in low-mass star formation is the "luminosity problem," whereby protostars are underluminous compared to the accretion luminosity expected both from theoretical collapse calculations and arguments based on the minimum accretion rate necessary to form a star within the embedded phase duration. Motivated by this luminosity problem, we present a set of evolutionary models describing the collapse of low-mass, dense cores into protostars. We use as our starting point the evolutionary model following the inside-out collapse of a singular isothermal sphere as presented by Young & Evans. We calculate the radiative transfer of the collapsing core throughout the full duration of the collapse in two dimensions. From the resulting spectral energy distributions, we calculate standard observational signatures (L(bol), T(bol), L(bol)/L(smm)) to directly compare to observations. We incorporate several modifications and additions to the original Young & Evans model in an effort to better match observations with model predictions; we include (1) the opacity from scattering in the radiative transfer, (2) a circumstellar disk directly in the two-dimensional radiative transfer, (3) a two-dimensional envelope structure, taking into account the effects of rotation, (4) mass-loss and the opening of outflow cavities, and (5) a simple treatment of episodic mass accretion. We find that scattering, two-dimensional geometry, mass-loss, and outflow cavities all affect the model predictions, as expected, but none resolve the luminosity problem. On the other hand, we find that a cycle of episodic mass accretion similar to that predicted by recent theoretical work can resolve this problem and bring the model predictions into better agreement with observations. Standard assumptions about the interplay between mass accretion and mass loss in our model give star formation efficiencies consistent with recent observations that compare the core mass function and stellar initial mass function. Finally, the combination of outflow cavities and episodic mass accretion reduces the connection between observational class and physical stage to the point where neither of the two commonly used observational signatures (T(bol) and L(bol)/L(smm)) can be considered reliable indicators of physical stage.NASA 1224608, 1288664, 1288658, RSA 1377304, NNX 07-AJ72GNSF AST0607793UT Austin University Continuing FellowshipAstronom

Symbolic Reachability Analysis of B through ProB and LTSmin

We present a symbolic reachability analysis approach for B that can provide a significant speedup over traditional explicit state model checking. The symbolic analysis is implemented by linking ProB to LTSmin, a high-performance language independent model checker. The link is achieved via LTSmin's PINS interface, allowing ProB to benefit from LTSmin's analysis algorithms, while only writing a few hundred lines of glue-code, along with a bridge between ProB and C using ZeroMQ. ProB supports model checking of several formal specification languages such as B, Event-B, Z and TLA. Our experiments are based on a wide variety of B-Method and Event-B models to demonstrate the efficiency of the new link. Among the tested categories are state space generation and deadlock detection; but action detection and invariant checking are also feasible in principle. In many cases we observe speedups of several orders of magnitude. We also compare the results with other approaches for improving model checking, such as partial order reduction or symmetry reduction. We thus provide a new scalable, symbolic analysis algorithm for the B-Method and Event-B, along with a platform to integrate other model checking improvements via LTSmin in the future

TMS-Induced Central Motor Conduction Time at the Non-Infarcted Hemisphere Is Associated with Spontaneous Motor Recovery of the Paretic Upper Limb after Severe Stroke

Background: Stroke affects the neuronal networks of the non-infarcted hemisphere. The central motor conduction time (CMCT) induced by transcranial magnetic stimulation (TMS) could be used to determine the conduction time of the corticospinal tract of the non-infarcted hemisphere after a stroke. Objectives: Our primary aim was to demonstrate the existence of prolonged CMCT in the non-infarcted hemisphere, measured within the first 48 h when compared to normative data, and secondly, if the severity of motor impairment of the affected upper limb was significantly associated with prolonged CMCTs in the non-infarcted hemisphere when measured within the first 2 weeks post stroke. Methods: CMCT in the non-infarcted hemisphere was measured in 50 patients within 48 h and at 11 days after a first-ever ischemic stroke. Patients lacking significant spontaneous motor recovery, so-called non-recoverers, were defined as those who started below 18 points on the FM-UE and showed less than 6 points (10%) improvement within 6 months. Results: CMCT in the non-infarcted hemisphere was prolonged in 30/50 (60%) patients within 48 h and still in 24/49 (49%) patients at 11 days. Sustained prolonged CMCT in the non-infarcted hemisphere was significantly more frequent in non-recoverers following FM-UE. Conclusions: The current study suggests that CMCT in the non-infarcted hemisphere is significantly prolonged in 60% of severely affected, is-chemic stroke patients when measured within the first 48 h post stroke. The likelihood of CMCT is significantly higher in non-recoverers when compared to those that show spontaneous motor recovery early post stroke

Living with a Hereditary Form of Cancer: Experiences and Needs of MEN 2 Patients and Their Families

Unlike the purely medical research done in multiple endocrine neoplasia type 2 (MEN 2) families, little work has been done on the psychosocial aspects of the disease. To assess the severely stressful influences and the consequences of that stress on the family network, a small-scale survey was carried out during a national meeting. The goal of the study was to obtain more information about the experiences and needs of MEN 2 patients and their relatives. Of the 59 respondents, 85% were satisfied with the medical information provided, 81% were satisfied with the medical knowledge of the specialist, but only 12% were satisfied with the medical knowledge of the general practitioner regarding MEN 2. Furthermore, 63% of the parents had difficulties in talking about the disease with their children. The need expressed for contact with fellow sufferers and their families is expected to lead to the establishment of an interest group for MEN 2 families

Force budget: III, Application to three-dimensional flow of Byrd Glacier, Antarctica

This is the published version, also available here: http://dx.doi.org/10.3189/002214389793701554.Stresses at the surface and at depth are calculated for a stretch of Byrd Glacier, Antarctica. The calculations are based on photogrammetrically determined velocities and elevations, and on radio-echo-determined ice thicknesses. The results are maps of drags from each valley wall, of normal forces laterally and longitudinally. and of basal drag. Special challenges in the calculation are the numerical gridding of velocity, ensuring that unreasonable short-wavelength features do not develop in the calculation, and inference of ice thickness where there are no data. The results show important variations in basal drag. For the floating part, basal drag is near zero, as expected. Within the grounded part. longitudinal components of basal drag are very variable, reaching 300 kPa with a dominant wavelength of 13 km. Generally. these drag maxima correlate with maxima in driving stress. Usually the across-glacier component of basal drag is small. An important exception occurs in the center of the grounded part of the glacier where the flow shows major deviations from the axis of the valley. Other results are that side drag is roughly constant at 250 kPa along both margins of the glacier, tension from the ice shelf is about 100 kPa, and tension in the grounded part cycles between 250 and 150 kPa. Calculated deep velocities are too large and this is attributed to deficiencies in the conventional isotropic flow law used

Epidemiology of burn patients admitted in the Netherlands:: a nationwide registry study investigating incidence rates and hospital admission from 2014 to 2018

PURPOSE: The aim of this study was to gain insight into the epidemiology of burn patients admitted to a hospital without a burn center or referred to a burn center. METHODS: This retrospective, nationwide, cohort study included patients with burns or inhalation trauma, admitted between 2014 and 2018, from a national trauma registry. The primary outcome measure was admission to a hospital with or without a burn center. Secondary outcome measures were patient and injury characteristics, Intensive Care Unit (ICU) admission and length of stay, and hospital length of stay (HLOS). RESULTS: Of the 5524 included patients, 2787 (50.4%) were treated at a non-burn center, 1745 (31.6%) were subsequently transferred to a burn center, and 992 (18.0%) were primarily presented and treated at a burn center. The annual number of patients decreased from 1199 to 1055 (− 12.4%). At all admission locations, a clear incidence peak was observed in children ≤ 4 years and in patients of ≥ 80 years. The number of ICU admissions for the entire population increased from 201 to 233 (33.0%). The mean HLOS for the entire population was 8 (SD 14) days per patient. This number remained stable over the years in all groups. CONCLUSION: Half of all burn patients were admitted in a non-burn center and the other half in a burn center. The number and incidence rate of patients admitted with burns or inhalation trauma decreased over time. An increased incidence rate was found in children and elderly. The number of patients admitted to the ICU increased, whereas mean hospital length of stay remained stable. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00068-021-01777-y

The ResPig program as a tool for identifying risk factors affecting technical performance and post-mortem results at the slaughterhouse on Dutch pig farms and for restrictive antibiotic use

The pig industry nowadays faces more complex diseases than ever before, such as Porcine Multi Systemic Wasting Syndrome and Porcine Respiratory Disease Complex. These disease entities are often caused by multiple infections combined with suboptimal conditions in the field of environment, management, biosecurity climatic conditions and more. Successful preventive plans include the identification of infectious and non infectious factors and preventive interventions based on this. Regarding PMWS, Madec formulated a list of 20 management measures and this was already quite successful in reducing the impact of that syndrome

Should Patients with Medullary Thyroid Carcinoma Undergo Extensive Lymph Node (Re)Operation to Improve Long-term Survival?

To investigate the role of primary and/or secondary modified radical neck dissection (MRND) in patients with medullary thyroid carcinoma (MTC), follow-up data on 43 patients operated on between 1972 and 1983 were analyzed retrospectively; patients included 16 with sporadic MTC (group 1) and 27 with multiple endocrine neoplasia type 2 (group 2). Primary surgical therapy consisted of (near-) total thyroidectomy and limited lymph node dissection: one patient in group 1 and two in group 2 underwent primary MRND. Positive nodes were found in nine patients of group 1 and in 12 of group 2. Calcitonin (CT) was raised postoperatively in 11 group 1 patients, who all died (four after additional MRND). Postoperative CT was normal in the four survivors of group 1. In group 2. postoperative CT was raised in 15 patients, including those who had MRND and in four apparently nodenegative patients. Three of them underwent additional MRND, which was successful in one case. One patient in this group died of the disease: two patients developed elevated CT levels during follow-up, whereas in one, CT normalized spontaneously. In conclusion, the role of extensive lymph node surgery in patients with more than limited lymph node involvement or elevated postoperative CT levels remains to be established