Resolving the ISM at the Peak of Cosmic Star Formation with ALMA: The Distribution of CO and Dust Continuum in z ∼ 2.5 Submillimeter Galaxies

We use Atacama Large Millimeter Array (ALMA) observations of four submillimeter galaxies (SMGs) at z ~ 2–3 to investigate the spatially resolved properties of the interstellar medium (ISM) at scales of 1–5 kpc (0farcs1–0farcs6). The velocity fields of our sources, traced by the 12CO(J = 3–2) emission, are consistent with disk rotation to the first order, implying average dynamical masses of ~3 × 1011 ${M}_{\odot }$ within two half-light radii. Through a Bayesian approach we investigate the uncertainties inherent to dynamically constraining total gas masses. We explore the covariance between the stellar mass-to-light ratio and CO-to-H2 conversion factor, α CO, finding values of ${\alpha }_{\mathrm{CO}}={1.1}_{-0.7}^{+0.8}$ for dark matter fractions of 15%. We show that the resolved spatial distribution of the gas and dust continuum can be uncorrelated to the stellar emission, challenging energy balance assumptions in global SED fitting. Through a stacking analysis of the resolved radial profiles of the CO(3–2), stellar, and dust continuum emission in SMG samples, we find that the cool molecular gas emission in these sources (radii ~5–14 kpc) is clearly more extended than the rest-frame ~250 μm dust continuum by a factor >2. We propose that assuming a constant dust-to-gas ratio, this apparent difference in sizes can be explained by temperature and optical depth gradients alone. Our results suggest that caution must be exercised when extrapolating morphological properties of dust continuum observations to conclusions about the molecular gas phase of the interstellar medium (ISM)

An ALMA survey of submillimetre galaxies in the Extended Chandra Deep Field-South: detection of [C II] at z = 4.4

We present Atacama Large Millimeter Array (ALMA) 870-μm (345-GHz) observations of two submillimetre galaxies (SMGs) drawn from an ALMA study of the 126 submillimetre sources from the LABOCA Extended Chandra Deep Field-South Survey (LESS). The ALMA data identify the counterparts to these previously unidentified submillimetre sources and serendipitously detect bright emission lines in their spectra which we show are most likely to be [CII] 157.74 μm emission yielding redshifts of z = 4.42 and 4.44. This blind detection rate within the 7.5-GHz bandpass of ALMA is consistent with the previously derived photometric redshift distribution of SMGs and suggests a modest, but not dominant (≲25 per cent), tail of 870-μm selected SMGs at z ≳ 4. We find that the ratio of L[C II]/LFIR in these SMGs is much higher than seen for similarly far-infrared-luminous galaxies at z ˜ 0, which is attributed to the more extended gas reservoirs in these high-redshift ultraluminous infrared galaxies (ULIRGs). Indeed, in one system we show that the [C II] emission shows hints of extended emission on ≳ 3 kpc scales. Finally, we use the volume probed by our ALMA survey to show that the bright end of the [C II] luminosity function evolves strongly between z = 0 and ˜4.4, reflecting the increased interstellar medium cooling in galaxies as a result of their higher star formation rates. These observations demonstrate that even with short integrations, ALMA is able to detect the dominant fine-structure cooling lines from high-redshift ULIRGs, measure their energetics and spatially resolved properties and trace their evolution with redshift

No relation between body temperature and arterial recanalization at three days in patients with acute ischaemic stroke

Background: Recanalization of an occluded intracranial artery is influenced by temperature-dependent enzymes, including alteplase. We assessed the relation between body temperature on admission and recanalization. Methods: We included 278 patients with acute ischaemic stroke within nine hours after symptom onset, who had an intracranial arterial occlusion on admission CT angiography, in 13 participating centres. We calculated the relation per every 0.1°Celsius increase in admission body temperature and recanalization at three days. Results: Recanalization occurred in 80% of occluded arteries. There was no relation between body temperature and recanalization at three days after adjustments for age, NIHSS score on admission and treatment with alteplase (adjusted odds ratio per 0.1°Celsius, 0.99; 95% confidence interval, 0.94-1.05; p = 0.70). Results for patients treated or not treated with alteplase were essentially the same. Conclusions: Our findings suggest that in patients with acute ischaemic stroke there is no relation between body temperature on admission and recanalization of an occluded intracranial artery three days later, irrespective of treatment with alteplase

Diagnostic yield and accuracy of CT angiography, MR angiography, and digital subtraction angiography for detection of macrovascular causes of intracerebral haemorrhage: Prospective, multicentre cohort study

Study question What are the diagnostic yield and accuracy of early computed tomography (CT) angiography followed by magnetic resonance imaging/angiography (MRI/MRA) and digital subtraction angiography (DSA) in patients with non-traumatic intracerebral haemorrhage? Methods This prospective diagnostic study enrolled 298 adults (18-70 years) treated in 22 hospitals in the Netherlands over six years. CT angiography was performed within seven days of haemorrhage. If the result was negative, MRI/MRA was performed four to eight weeks later. DSA was performed when the CT angiography or MRI/MRA results were inconclusive or negative. The main outcome was a macrovascular cause, including arteriovenous malformation, aneurysm, dural arteriovenous fistula, and cavernoma. Three blinded neuroradiologists independently evaluated the images for macrovascular causes of haemorrhage. The reference standard was the best available evidence from all findings during one year's follow-up. Study answer and limitations A macrovascular cause was identified in 69 patients (23%). 291 patients (98%) underwent CT angiography; 214 with a negative result underwent additional MRI/MRA and 97 with a negative result for both CT angiography and MRI/MRA underwent DSA. Early CT angiography detected 51 macrovascular causes (yield 17%, 95% confidence interval 13% to 22%). CT angiography with MRI/MRA identified two additional macrovascular causes (18%, 14% to 23%) and these modalities combined with DSA another 15 (23%, 18% to 28%). This last extensive strategy failed to detect a cavernoma, which was identified on MRI during follow-up (reference strategy). The positive predictive value of CT angiography was 72% (60% to 82%), of additional MRI/MRA was 35% (14% to 62%), and of additional DSA was 100% (75% to 100%). None of the patients experienced complications with CT angiography or MRI/MRA; 0.6% of patients who underwent DSA experienced p

Temporal profile of body temperature in acute ischemic stroke: Relation to infarct size and outcome

Background: High body temperatures after ischemic stroke have been associated with larger infarct size, but the temporal profile of this relation is unknown. We assess the relation between temporal profile of body temperature and infarct size and functional outcome in patients with acute ischemic stroke. Methods: In 419 patients with acute ischemic stroke we assessed the relation between body temperature on admission and during the first 3 days with both infarct size and functional outcome. Infarct size was measured in milliliters on CT or MRI after 3 days. Poor functional outcome was defined as a modified Rankin Scale score ≥3 at 3 months. Results: Body temperature on admission was not associated with infarct size or poor outcome in adjusted analyses. By contrast, each additional 1.0 °C in body temperature on day 1 was associated with 0.31 ml larger infarct size (95% confidence interval (CI) 0.04-0.59), on day 2 with 1.13 ml larger infarct size(95% CI, 0.83-1.43), and on day 3 with 0.80 ml larger infarct size (95% CI, 0.48-1.12), in adjusted linear regression analyses. Higher peak body temperatures on days two and three were also associated with poor outcome (adjusted relative risks per additional 1.0 °C in body temperature, 1.52 (95% CI, 1.17-1.99) and 1.47 (95% CI, 1.22-1.77), respectively). Conclusions: Higher peak body temperatures during the first days after ischemic stroke, rather than on admission, are associated with larger infarct size and poor functional outcome. This suggests that prevention of high temperatures may improve outcome if continued for at least 3 days

A Virtual Testing Approach for Laminated Composites Based on Micromechanics

International audienceThe chapter deals with a crucial question for the design of composite structures: how can one predict the evolution of damage up to and including final fracture? Virtual testing, whose goal is to drastically reduce the huge number of industrial tests involved in current characterization procedures, constitutes one of today’s main industrial challenges. In this work, one revisits our multiscale modeling answer through its practical aspects. Some complements regarding identification, kinking, and crack initiation are also given. Finally, the current capabilities and limits of this approach are discussed, as well as the computational challenges that are inherent to “Virtual Structural Testing.

The Danish High Risk and Resilience Study-VIA 11: Study Protocol for the First Follow-Up of the VIA 7 Cohort -522 Children Born to Parents With Schizophrenia Spectrum Disorders or Bipolar Disorder and Controls Being Re-examined for the First Time at Age 11.

Introduction: Offspring of parents with severe mental illness have an increased risk of developing mental illnesses themselves. Familial high risk cohorts give a unique opportunity for studying the development over time, both the illness that the individual is predisposed for and any other diagnoses. These studies can also increase our knowledge of etiology of severe mental illness and provide knowledge about the underlying mechanisms before illness develops. Interventions targeting this group are often proposed due to the potential possibility of prevention, but evidence about timing and content is lacking. Method: A large, representative cohort of 522 7-year old children born to parents with schizophrenia, bipolar disorder or controls was established based on Danish registers. A comprehensive baseline assessment including neurocognition, motor functioning, psychopathology, home environment, sociodemographic data, and genetic information was conducted from January 1, 2013 to January 31, 2016. This study is the first follow-up of the cohort, carried out when the children turn 11 years of age. By assessing the cohort at this age, we will evaluate the children twice before puberty. All instruments have been selected with a longitudinal perspective and most of them are identical to those used at inclusion into the study at age 7. A diagnostic interview, motor tests, and a large cognitive battery are conducted along with home visits and information from teachers. This time we examine the children's brains by magnetic resonance scans and electroencephalograms. Measures of physical activity and sleep are captured by a chip placed on the body, while we obtain biological assays by collecting blood samples from the children. Discussion: Findings from the VIA 7 study revealed large variations across domains between children born to parents with schizophrenia, bipolar and controls, respectively. This study will further determine whether the children at familial risk reveal delayed developmental courses, but catch up at age 11, or whether the discrepancies between the groups have grown even larger. We will compare subgroups within each of the familial high risk groups in order to investigate aspects of resilience. Data on brain structure and physical parameters will add a neurobiological dimension to the study

Intracranial Cerebrospinal Fluid Volume as a Predictor of Malignant Middle Cerebral Artery Infarction

Background and Purpose— Predicting malignant middle cerebral artery (MCA) infarction can help to identify patients who may benefit from preventive decompressive surgery. We aimed to investigate the association between the ratio of intracranial cerebrospinal fluid (CSF) volume to intracranial volume (ICV) and malignant MCA infarction. Methods— Patients with an occlusion proximal to the M3 segment of the MCA were selected from the DUST (Dutch Acute Stroke Study). Admission imaging included noncontrast computed tomography (CT), CT perfusion, and CT angiography. Patient characteristics and CT findings were collected. The ratio of intracranial CSF volume to ICV (CSF/ICV) was quantified on admission thin-slice noncontrast CT. Malignant MCA infarction was defined as a midline shift of >5 mm on follow-up noncontrast CT, which was performed 3 days after the stroke or in case of clinical deterioration. To test the association between CSF/ICV and malignant MCA infarction, odds ratios and 95% CIs were calculated for 3 multivariable models by using binary logistic regression. Model performances were compared by using the likelihood ratio test. Results— Of the 286 included patients, 35 (12%) developed malignant MCA infarction. CSF/ICV was independently associated with malignant MCA infarction in 3 multivariable models: (1) with age and admission National Institutes of Health Stroke Scale (odds ratio, 3.3; 95% CI, 1.1–11.1), (2) with admission National Institutes of Health Stroke Scale and poor collateral score (odds ratio, 7.0; 95% CI, 2.6–21.3), and (3) with terminal internal carotid artery or proximal M1 occlusion and poor collateral score (odds ratio, 7.7; 95% CI, 2.8–23.9). The performance of model 1 (areas under the receiver operating characteristic curves, 0.795 versus 0.824; P=0.033), model 2 (areas under the receiver operating characteristic curves, 0.813 versus 0.850; P<0.001), and model 3 (areas under the receiver operating characteristic curves, 0.811 versus 0.856; P<0.001) improved significantly after adding CSF/ICV. Conclusions— The CSF/ICV ratio is associated with malignant MCA infarction and has added value to clinical and imaging prediction models in limited numbers of patients

Untangling the effects of overexploration and overexploitation on organizational performance: The moderating role of environmental dynamism

Because a firm's optimal knowledge search behavior is determined by unique firm and industry conditions, organizational performance should be contingent oil the degree to which a firm's actual level of knowledge search deviates from the optimal level. It is thus hypothesized that deviation from the optimal search, in the form of either overexploitation or overexploration, is detrimental to organizational performance. Furthermore, the negative effect of search deviation oil organizational performance varies with environmental dynamism: that is, overexploitation is expected to become more harmful. whereas overexploration becomes less so with all increase in environmental dynamism. The empirical analyses yield results consistent with these arguments. Implications for research and practice are correspondingly discussed

Alien plant species that invade high elevations are generalists: support for the directional ecological filtering hypothesis

Questions: The richness of invasive alien plant species tends to decrease with increasing elevation. This pattern may be due to alien plant species requiring traits allowing survival at high elevations (the Abiotic Limitation Hypothesis; ALH). In contrast, the more recent Directional Ecological Filtering Hypothesis (DEFH) suggests that only species with broad environmental tolerances will successfully spread from lowlands (where most introductions occur) to high elevations. Here we test support for the DEFH and ALH along an elevational gradient by asking: (1) are alien species that occur at higher elevations generalists; and (2) do alien species occurring at higher elevations exhibit traits that distinguishes them fromlowland alien species? Location: Sani Pass, Maloti-Drakensberg Transfrontier Conservation Area, South Africa. Methods: A nestedness analysis was conducted to test whether alien species were nested along the elevational gradient, and ANOVA and Chi2 tests (supplemented by resampling procedures) were used to determine if functional traits differed between high- and low-elevation alien species. Results: Significant nestedness of the alien flora indicates that alien species occurring at high elevations are generalists, being widespread across the elevational gradient. Compared to low-elevation aliens, plant height was lower and cold toleranceweaker for high-elevation species. Conclusion: We found support for the DEFH, with the majority of high-elevation aliens being widespread generalists. Overall only two of the 11 functional traits differed between high- and low-elevation alien species, with only one trait supporting the ALH: shorter plant stature at higher elevations. Therefore, complementing nestedness analyses with trait data provides a more nuanced insight into the determinants of alien richness patterns along elevational gradients, and highlights how the two contemporary hypotheses might not be mutually exclusive