Evolution of the Halpha luminosity function

The Smithsonian Hectospec Lensing Survey (SHELS) is a window on the star formation history over the last 4 Gyr. SHELS is a spectroscopically complete survey for Rtot < 20.3 over 4 square degrees. We use the 10k spectra to select a sample of pure star forming galaxies based on their Halpha emission line. We use the spectroscopy to determine extinction corrections for individual galaxies and to remove active galaxies in order to reduce systematic uncertainties. We use the large volume of SHELS with the depth of a narrowband survey for Halpha galaxies at z ~ 0.24 to make a combined determination of the Halpha luminosity function at z ~ 0.24. The large area covered by SHELS yields a survey volume big enough to determine the bright end of the Halpha luminosity function from redshift 0.100 to 0.377 for an assumed fixed faint-end slope alpha = -1.20. The bright end evolves: the characteristic luminosity L* increases by 0.84 dex over this redshift range. Similarly, the star formation density increases by 0.11 dex. The fraction of galaxies with a close neighbor increases by a factor of 2-5 for L(Halpha) >~ L* in each of the redshift bins. We conclude that triggered star formation is an important influence for star forming galaxies with Halpha emission.Comment: 26 pages, 23 figures, submitted to ApJ; version with high resolution figures available at http://www.cfa.harvard.edu/~ewestra/publications

Multi-Object Near-IR H-alpha Spectroscopy of z~1 star-forming galaxies in the HDF-N

We present preliminary results from a programme to obtain multi-object near-infrared spectroscopy of galaxies at redshifts $0.7<z<1.5$. We are using the instrument CIRPASS (the Cambridge Infra-Red PAnoramic Survey Spectrograph), in multi-object mode, to survey H-alpha in galaxies at $z\sim1$. We aim to address the true star formation history of the universe at this epoch: potentially the peak period of star formation activity. H-alpha is the same star formation measure used at low redshift, and hence we can trace star formation without the systematic uncertainties of using different calibrators in different redshift bins, or the extreme dust extinction in the rest-UV. CIRPASS has been successfully demonstrated in multi-object mode on the AAT and WHT. Here we present preliminary results from one of our fields, the Hubble Deep Field North, observed with the WHT. With 150 fibres deployed over an unvignetted field of $\sim15$arcmin, we have several detections of H-alpha from star forming galaxies at $0.8<z<1.0$ and present spectra of the seven brightest of these. By pre-selecting galaxies with redshifts such that H-alpha will appear between the OH sky lines, we can detect star formation rates of $5 h^{-2}_{70} M_{\odot} {\rm yr}^{-1}$ ($5 \sigma$ in 3-hours, $\Omega_M=0.3$, $\Omega_{\Lambda}=0.7$). It appears that star formation rates inferred from H-alpha are, on average, a factor of more than two higher than those based on the UV continuum alone.Comment: 6 pages, 3 figures, accepted for publication in MNRAS Letter

GLP-1 action in the mouse bed nucleus of the stria terminalis

Glucagon-like peptide-1 (GLP-1) injected into the brain reduces food intake. Similarly, activation of preproglucagon (PPG) cells in the hindbrain which synthesize GLP-1, reduces food intake. However, it is far from clear whether this happens because of satiety, nausea, reduced reward, or even stress. Here we explore the role of the bed nucleus of the stria terminalis (BNST), an area involved in feeding control as well as stress responses, in GLP-1 responses. Using cre-expressing mice we visualized projections of NTS PPG neurons and GLP-1R-expressing BNST cells with AAV-driven Channelrhodopsin-YFP expression. The BNST displayed many varicose YFP+ PPG axons in the ventral and less in the dorsal regions. Mice which express RFP in GLP-1R neurons had RFP+ cells throughout the BNST with the highest density in the dorsal part, suggesting that PPG neuron-derived GLP-1 acts in the BNST. Indeed, injection of GLP-1 into the BNST reduced chow intake during the dark phase, whereas injection of the GLP-1 receptor antagonist Ex9 increased feeding. BNST-specific GLP-1-induced food suppression was less effective in mice on high fat (HF, 60%) diet, and Ex9 had no effect. Restraint stress-induced hypophagia was attenuated by BNST Ex9 treatment, further supporting a role for endogenous brain GLP-1. Finally, whole-cell patch clamp recordings of RFP+ BNST neurons demonstrated that GLP-1 elicited either a depolarizing or hyperpolarizing reversible response that was of opposite polarity to that under dopamine. Our data support a physiological role for BNST GLP-1R in feeding, and suggest complex cellular responses to GLP-1 in this nucleus

The K20 survey. VI. The Distribution of the Stellar Masses in Galaxies up to z~2

We present a detailed analysis of the stellar mass content of galaxies up to z=2.5 in the K20 galaxy sample, that has a 92% spectroscopic completeness and a complete $UBVRIzJK_s$ multicolor coverage. We find that the M/L ratio decreases with redshift: in particular, the average M/L ratio of early type galaxies decreases with $z$, with a scatter that is indicative of a range of star--formation time-scales and redshift of formation. More important, the typical M/L of massive early type galaxies is larger than that of less massive ones, suggesting that their stellar population formed at higher z. The final K20 galaxy sample spans a range of stellar masses from M*=10^9Msun to M*=10^12Msun, with massive galaxies ($M*>10^11Msun) detected up to z~2. We compute the Galaxy Stellar Mass Function at various z, of which we observe only a mild evolution (i.e. by 20-30%) up to z~1. At z>1, the evolution of the GSMF appears to be much faster: at z~2, about 35% of the present day stellar mass in objects with M*~10^11Msun appear to have assembled. We also detect a change in the physical nature of the most massive galaxies, since at z>1 a population of massive star--forming galaxies progressively appears. We finally analyze our results in the framework of Lambda-CDM hierarchical models. First, we show that the large number of massive galaxies detected at high z does not violate any fundamental Lambda-CDM constraint based on the number of massive DM halos. Then, we compare our results with the predictions of renditions of both semianalytic and hydro-dynamical models, that range from severe underestimates to slight overestimates of the observed mass density at z<~2. We discuss how the differences among these models are due to the different implementation of the main physical processes. (Abridged)Comment: Accepted for publication on Astronomy & Astrophysic

The impact of preexisting and post-transplant diabetes mellitus on outcomes following liver transplantation

Background: Diabetes mellitus (DM) is said to adversely affect transplant outcomes. The aim of this study was to investigate the impact of pre-existing and post-transplant DM on liver transplant (LT) recipients.Method: A single centre retrospective analysis of prospectively collected data of LT recipients (1990–2015) was undertaken.Results: Of the 2,209 patients, 13% (n=298) had Pre-DM, 16% (n=362) developed PTDM, 5% (n=118) developed transient hyperglycemia (t-HG) post-LT, and 65% (n=1,431) never developed DM (no DM). Baseline clinical characteristics of patients with PTDM was similar to that of patients with pre-DM. Incidence of PTDM peaked during first-year (87%) and plateaued thereafter. On multivariate analysis (Bonferroni-corrected), non-alcoholic fatty liver disease and the use of Tacrolimus and Sirolimus use were independently associated with PTDM development. Both Pre-DM and PTDM patients had satisfactory and comparable glycaemic control throughout the follow-up period. Those who developed t-HG seems to have a unique characteristic compared to others. Overall, 9%, 5%, and 8% developed end-stage renal disease (ESRD), major cardiovascular event (mCVE), and de novo cancer, respectively. Both Pre-DM and PTDM did not adversely affect patient survival, re-LT, or de novo cancer. The risks of ESRD and mCVE were significantly higher in patients with Pre-DM followed by PTDM and no DM.Conclusions: In this largest non-registry study, patients with pre-DM and PTDM share similar baseline clinical characteristics. Pre-DM increases the risk of ESRD and mCVE; however, patient survival was comparable to those with PTDM and without diabetes. Understanding the impact of PTDM would need prolonged follow-up

Discerning suicide in drug intoxication deaths: Paucity and primacy of suicide notes and psychiatric history

Objective A paucity of corroborative psychological and psychiatric evidence may be inhibiting detection of drug intoxication suicides in the United States. We evaluated the relative importance of suicide notes and psychiatric history in the classification of suicide by drug intoxication versus firearm (gunshot wound) plus hanging/suffocation—the other two major, but overtly violent methods. Methods This observational multilevel (individual/county), multivariable study employed a generalized linear mixed model (GLMM) to analyze pooled suicides and undetermined intent deaths, as possible suicides, among the population aged 15 years and older in the 17 states participating in the National Violent Death Reporting System throughout 2011–2013. The outcome measure was relative odds of suicide versus undetermined classification, adjusted for demographics, precipitating circumstances, and investigation characteristics. Results A suicide note, prior suicide attempt, or affective disorder was documented in less than one-third of suicides and one-quarter of undetermined deaths. The prevalence gaps were larger among drug intoxication cases than gunshot/hanging cases. The latter were more likely than intoxication cases to be classified as suicide versus undetermined manner of death (adjusted odds ratio [OR], 41.14; 95% CI, 34.43–49.15), as were cases documenting a suicide note (OR, 33.90; 95% CI, 26.11–44.05), prior suicide attempt (OR, 2.42; 95% CI, 2.11–2.77), or depression (OR, 1.61; 95% CI, 1.38 to 1.88), or bipolar disorder (OR, 1.41; 95% CI, 1.10–1.81). Stratification by mechanism/cause intensified the association between a note and suicide classification for intoxication cases (OR, 45.43; 95% CI, 31.06–66.58). Prior suicide attempt (OR, 2.64; 95% CI, 2.19–3.18) and depression (OR, 1.48; 95% CI, 1.17–1.87) were associated with suicide classification in intoxication but not gunshot/hanging cases. Conclusions Without psychological/psychiatric evidence contributing to manner of death classification, suicide by drug intoxication in the US is likely profoundly under-reported. Findings harbor adverse implications for surveillance, etiologic understanding, and prevention of suicides and drug deaths

Editor's Choice - The Impact of Centralisation and Endovascular Aneurysm Repair on Treatment of Ruptured Abdominal Aortic Aneurysms Based on International Registries

Objectives: Current management of ruptured abdominal aortic aneurysms (RAAA) varies among centres and countries, particularly in the degree of implementation of endovascular aneurysm repair (EVAR) and levels of vascular surgery centralisation. This study assesses these variations and the impact they have on outcomes. Materials and methods: RAAA repairs from vascular surgical registries in 11 countries, 2010-2013, were investigated. Data were analysed overall, per country, per treatment modality (EVAR or open aortic repair [OAR]), centre volume (quintiles IV), and whether centres were predominantly EVAR (>= 50% of RAAA performed with EVAR [EVAR(p)]) or predominantly OAR [OAR(p)]. Primary outcome was peri-operative mortality. Data are presented as either mean values or percentages with 95% CI within parentheses, and compared with chi-square tests, as well as with adjusted OR. Results: There were 9273 patients included. Mean age was 74.7 (74.5-74.9) years, and 82.7% of patients were men (81.9-83.6). Mean AAA diameter at rupture was 7.6 cm (7.5-7.6). Of these aneurysms, 10.7% (10.0-11.4) were less than 5.5 cm. EVAR was performed in 23.1% (22.3-24.0). There were 6817 procedures performed in OAR(p) centres and 1217 performed in EVAR(p) centres. Overall peri-operative mortality was 28.8% (27.9-29.8). Peri-operative mortality for OAR was 32.1% (31.0-33.2) and for EVAR 17.9% (16.3-19.6), p 22 repairs per year), 23.3% (21.2-25.4) than in QII-V, 30.0% (28.9-31.1), p <.001. Peri-operative mortality after OAR was lower in high volume centres compared with the other centres, 25.3% (23.0-27.6) and 34.0% (32.7-35.4), respectively, p <.001. There was no significant difference in peri-operative mortality after EVAR between centres based on volume. Conclusions: Peri-operative mortality is lower in centres with a primary EVAR approach or with high case volume. Most repairs, however, are still performed in low volume centres and in centres with a primary OAR strategy. Reorganisation of acute vascular surgical services may improve outcomes of RAAA repair. (C) 2018 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.Peer reviewe

Outcomes of Radiofrequency Ablation as First-Line Therapy for Hepatocellular Carcinoma less than 3 cm in Potentially Transplantable Patients

© 2019 European Association for the Study of the Liver Background & Aims: Radiofrequency ablation (RFA) is an effective treatment for single hepatocellular carcinoma (HCC) ≤3 cm. Disease recurrence is common, and in some patients will occur outside transplant criteria. We aimed to assess the incidence and risk factors for recurrence beyond Milan criteria in potentially transplantable patients treated with RFA as first-line therapy. Methods: We performed a retrospective cohort study of potentially transplantable patients with new diagnoses of unifocal HCC ≤3 cm that underwent RFA as first-line therapy between 2000-2015. We defined potentially transplantable patients as those aged 2 cm). Competing risks Cox regression was used to identify predictors of recurrence beyond Milan criteria. Results: We included 301 patients (167 HCC ≤2 cm and 134 HCC >2 cm). Recurrence beyond Milan criteria occurred in 36 (21.6%) and 47 (35.1%) patients in the HCC ≤2 cm and the HCC >2 cm groups, respectively (p = 0.01). The 1-, 3- and 5-year actuarial survival rates after RFA were 98.2%, 86.2% and 79.0% in the HCC ≤2 cm group vs. 93.3%, 77.6% and 70.9% in the HCC >2 cm group (p = 0.01). Tumor size >2 cm (hazard ratio 1.94; 95% CI 1.25–3.02) and alpha-fetoprotein levels at the time of ablation (100–1,000 ng/ml: hazard ratio 2.05; 95% CI 1.10–3.83) were found to be predictors of post-RFA recurrence outside Milan criteria. Conclusion: RFA for single HCC ≤3 cm provides excellent short- to medium-term survival. However, we identified patients at higher risk of recurrence beyond Milan criteria. For these patients, liver transplantation should be considered immediately after the first HCC recurrence following RFA. Lay summary: Radiofrequency ablation and liver transplantation are treatment options for early stages of hepatocellular carcinoma (HCC). After ablation some patients will experience recurrence or metastatic spread of the initial tumor or may develop new tumors within the liver. Despite close follow-up, these recurrences can progress rapidly and exceed transplant criteria, preventing the patient from receiving a transplant. We identified that patients with HCC >2 cm and higher serum alpha-fetoprotein are at greater risk of recurrence beyond the transplant criteria. These data suggest that liver transplantation should be considered immediately after the first HCC recurrence for these patients

An HST Morphological Survey of Faint EROs

We present the results from a survey for Extremely Red Objects (EROs) in deep, high resolution optical images taken from the Hubble Space Telescope (HST) Medium Deep Survey. We have surveyed 35 deep F814W HST/WFPC2 fields in the near-infrared to a typical depth of K~20. From a total area of 206 arcmin^2 and to a limit of K=20.0 we identify 224 EROs ((1.14+/-0.08) arcmin^-2) with (I_{814}-K)=>4.0 and 83 ((0.41+/-0.05) arcmin^-2) with (I_{814}-K)=>5.0. We find that the slope of the number counts of the (I_{814}-K)=>4.0 EROs flattens beyond K~19, in line with results from previous surveys, and the typical colours of the EROs become redder beyond the break magnitude. We morphologically classify our ERO sample using visual and quantitative schemes and find that 35% of our sample exhibit clear disk components, 15% are disturbed or irregular, a further 30% are either spheroidal or compact and the remaining 20% are unclassifiable. Using a quantitative measure of morphology, we find that the ERO morphological distribution evolves across the break in their counts, such that low concentration (disk-like) galaxies decline. We relate the morphological and colour information for our EROs and conclude that those EROs morphologically classified as bulges do indeed possess SEDs consistent with passive stellar populations; while EROs with dusty star-forming SEDs are mostly associated with disk-like and peculiar galaxies. However, ~30% of disk EROs reside in the passive region of I/J/K colour-colour space. These could be either genuinely passive systems, lower redshift contaminants to the high-z ERO population, or systems with composite star-forming and passive SEDs.Comment: 20 pages, 14 figures. MNRAS submitted, revised in response to referee's comment

Soils and palaeo-climate based evidence for irrigation requirements in Norse Greenland

Establishing and sustaining agricultural production was a key factor in the success of Norse settlements during the landnám colonisation across the North Atlantic. In light of the occurrence of channel features in several abandoned home-field areas of the Norse Eastern Settlement of Greenland, and the irrigation requirements of present-day Greenlandic sheep-farmers questions are raised: was irrigation used by the Norse settlers of Greenland on their home-field areas? and, if so, how frequently? Modelling of soil chemical, physical and soil-water hydraulic properties integrated with contemporary high-resolution climatic data demonstrate a frequent requirement for irrigation. Soil moisture deficits are related to the duration and intensity of winter temperature. Using the winter Dye 3 ice core δ18O record as a climatic proxy, the frequency of moisture deficits, based on comparing mean winter temperatures, indicates that there was a frequent irrigation requirement to maintain home-field productivity, increasing throughout the period of settlement until the 14th Century