2,714 research outputs found

    Who Are Social Entrepreneurs? Connecting the Stories of Women in the Global Textile and Apparel Industry

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    Current definitions of social entrepreneurs appear limited in view, delineating social-entrepreneurs as outside elites with special qualities and their work to be complex and lavish. Definitions of social entrepreneurs fail to capture and illustrate the multitudes and diversity of social entrepreneurship. Thus, social entrepreneurship needs refashioning to address the multiple types of intentions (feasibility and desirability) to act, opportunities, and capacities. The present interpretation lacks a holistic standpoint. Using a scenario of analysis of the textile and apparel industry, it becomes evident that micro-entrepreneurs engage daily in solving the complex problem of poverty, unemployment, exploitation, and other social issues through self-employment. They are by their very nature practicing social entrepreneurship. The purpose of this concept paper is not to dispute current definitions of social entrepreneurs but to help make definitions more holistic, by recognizing the contributions of the multiple types of people and organization who attempt to solve societal concerns

    ZFIRE: The Evolution of the Stellar Mass Tully-Fisher Relation to Redshift 2.0 < Z < 2.5 with MOSFIRE

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    Using observations made with MOSFIRE on Keck I as part of the ZFIRE survey, we present the stellar mass Tully-Fisher relation at 2.0 < z < 2.5. The sample was drawn from a stellar mass limited, Ks-band selected catalog from ZFOURGE over the CANDELS area in the COSMOS field. We model the shear of the Halpha emission line to derive rotational velocities at 2.2X the scale radius of an exponential disk (V2.2). We correct for the blurring effect of a two-dimensional PSF and the fact that the MOSFIRE PSF is better approximated by a Moffat than a Gaussian, which is more typically assumed for natural seeing. We find for the Tully-Fisher relation at 2.0 < z < 2.5 that logV2.2 =(2.18 +/- 0.051)+(0.193 +/- 0.108)(logM/Msun - 10) and infer an evolution of the zeropoint of Delta M/Msun = -0.25 +/- 0.16 dex or Delta M/Msun = -0.39 +/- 0.21 dex compared to z = 0 when adopting a fixed slope of 0.29 or 1/4.5, respectively. We also derive the alternative kinematic estimator S0.5, with a best-fit relation logS0.5 =(2.06 +/- 0.032)+(0.211 +/- 0.086)(logM/Msun - 10), and infer an evolution of Delta M/Msun= -0.45 +/- 0.13 dex compared to z < 1.2 if we adopt a fixed slope. We investigate and review various systematics, ranging from PSF effects, projection effects, systematics related to stellar mass derivation, selection biases and slope. We find that discrepancies between the various literature values are reduced when taking these into account. Our observations correspond well with the gradual evolution predicted by semi-analytic models.Comment: 21 pages, 14 figures, 1 appendix. Accepted for publication by Apj, February 28, 201

    Validation of treatment escalation as a definition of atopic eczema flares.

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    BACKGROUND: Atopic eczema (AE) is a chronic disease with flares and remissions. Long-term control of AE flares has been identified as a core outcome domain for AE trials. However, it is unclear how flares should be defined and measured. OBJECTIVE: To validate two concepts of AE flares based on daily reports of topical medication use: (i) escalation of treatment and (ii) days of topical anti-inflammatory medication use (topical corticosteroids and/or calcineurin inhibitors). METHODS: Data from two published AE studies (studies A (n=336) and B (n=60)) were analysed separately. Validity and feasibility of flare definitions were assessed using daily global bother (scale 0 to 10) as the reference standard. Intra-class correlations were reported for continuous variables, and odds ratios and area under the receiver operator characteristic (ROC) curve for binary outcome measures. RESULTS: Good agreement was found between both AE flare definitions and change in global bother: area under the ROC curve for treatment escalation of 0.70 and 0.73 in studies A and B respectively, and area under the ROC curve of 0.69 for topical anti-inflammatory medication use (Study A only). Significant positive relationships were found between validated severity scales (POEM, SASSAD, TIS) and the duration of AE flares occurring in the previous week - POEM and SASSAD rose by half a point for each unit increase in number of days in flare. Smaller increases were observed on the TIS scale. Completeness of daily diaries was 95% for Study A and 60% for Study B over 16 weeks). CONCLUSION: Both definitions were good proxy indicators of AE flares. We found no evidence that 'escalation of treatment' was a better measure of AE flares than 'use of topical anti-inflammatory medications'. Capturing disease flares in AE trials through daily recording of medication use is feasible and appears to be a good indicator of long-term control. TRIAL REGISTRATION: Current Controlled Trials ISRCTN71423189 (Study A)

    ZFOURGE: Using Composite Spectral Energy Distributions to Characterize Galaxy Populations at 1<z<4

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    We investigate the properties of galaxies as they shut off star formation over the 4 billion years surrounding peak cosmic star formation. To do this we categorize 7000\sim7000 galaxies from 1<z<41<z<4 into 9090 groups based on the shape of their spectral energy distributions (SEDs) and build composite SEDs with R50R\sim 50 resolution. These composite SEDs show a variety of spectral shapes and also show trends in parameters such as color, mass, star formation rate, and emission line equivalent width. Using emission line equivalent widths and strength of the 4000\AA\ break, D(4000)D(4000), we categorize the composite SEDs into five classes: extreme emission line, star-forming, transitioning, post-starburst, and quiescent galaxies. The transitioning population of galaxies show modest Hα\alpha emission (EWREST40EW_{\rm REST}\sim40\AA) compared to more typical star-forming composite SEDs at log10(M/M)10.5\log_{10}(M/M_\odot)\sim10.5 (EWREST80EW_{\rm REST}\sim80\AA). Together with their smaller sizes (3 kpc vs. 4 kpc) and higher S\'ersic indices (2.7 vs. 1.5), this indicates that morphological changes initiate before the cessation of star formation. The transitional group shows a strong increase of over one dex in number density from z3z\sim3 to z1z\sim1, similar to the growth in the quiescent population, while post-starburst galaxies become rarer at z1.5z\lesssim1.5. We calculate average quenching timescales of 1.6 Gyr at z1.5z\sim1.5 and 0.9 Gyr at z2.5z\sim2.5 and conclude that a fast quenching mechanism producing post-starbursts dominated the quenching of galaxies at early times, while a slower process has become more common since z2z\sim2.Comment: Accepted for publication in The Astrophysical Journa

    The distribution of satellites around massive galaxies at 1<z<3 in ZFOURGE/CANDELS: dependence on star formation activity

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    We study the statistical distribution of satellites around star-forming and quiescent central galaxies at 1<z<3 using imaging from the FourStar Galaxy Evolution Survey (ZFOURGE) and the Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey (CANDELS). The deep near-IR data select satellites down to log(M/M)>9\log(M/M_\odot)>9 at z<3. The radial satellite distribution around centrals is consistent with a projected NFW profile. Massive quiescent centrals, log(M/M)>10.78\log(M/M_\odot)>10.78, have \sim2 times the number of satellites compared to star-forming centrals with a significance of 2.7σ\sigma even after accounting for differences in the centrals' stellar-mass distributions. We find no statistical difference in the satellite distributions of intermediate-mass quiescent and star-forming centrals, 10.48<log(M/M)<10.7810.48<\log(M/M_\odot)<10.78. Comparing to the Guo2011 semi-analytic model, the excess number of satellites indicates that quiescent centrals have halo masses 0.3 dex larger than star-forming centrals, even when the stellar-mass distributions are fixed. We use a simple toy model that relates halo mass and quenching, which roughly reproduces the observed quenched fractions and the differences in halo mass between star-forming and quenched galaxies only if galaxies have a quenching probability that increases with halo mass from \sim0 for log(Mh/M)\log(M_h/M_\odot)\sim11 to \sim1 for log(Mh/M)\log(M_h/M_\odot)\sim13.5. A single halo-mass quenching threshold is unable to reproduce the quiescent fraction and satellite distribution of centrals. Therefore, while halo quenching may be an important mechanism, it is unlikely to be the only factor driving quenching. It remains unclear why a high fraction of centrals remain star-forming even in relatively massive halos.Comment: 19 pages, 17 figures, accepted by ApJ. Information on ZFOURGE can be found at http://zfourge.tamu.ed

    Hypercalcemia of Malignancy Attributed to Cosecretion of PTH and PTHRP in Lung Adenocarcinoma

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    Introduction: Hypercalcemia of malignancy (HCM) portends a very poor prognosis, and no established guidelines exist regarding its management. Most instances of HCM are due to local osteolysis or secretion of parathyroid hormone related-peptide, while less than 1% of all cases are due to ectopic secretion of parathyroid hormone. Case report: We present an unusual case of HCM due to proposed cosecretion of both parathyroid hormone and parathyroid hormone-related protein in a 36-year-old man with a poorly differentiated lung adenocarcinoma. The patient\u27s hypercalcemia was refractory to conventional measures, including intravenous bisphosphonate therapy (zoledronic acid), and was improved with administration of denosumab. Conclusion: This is the youngest and first case of hypercalcemia of malignancy attributed to cosecretion of PTH and PTHrP from an adenocarcinoma. In refractory cases of HCM, denosumab is a potential option when other conventional measures are unsuccessful

    Beyond UVJ: Color Selection of Galaxies in the JWST Era

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    We present a new rest-frame color-color selection method using "synthetic usgsu_s-g_s and gsisg_s-i_s'', (ugi)s(ugi)_s colors to identify star-forming and quiescent galaxies. Our method is similar to the widely-used UVU-V versus VJV-J (UVJUVJ) diagram. However, UVJUVJ suffers known systematics. Spectroscopic campaigns have shown that UVJUVJ-selected quiescent samples at z3z \gtrsim 3 include 1030%\sim 10-30\% contamination from galaxies with dust-obscured star formation and strong emission lines. Moreover, at z>3z>3, UVJUVJ colors are extrapolated because the rest-frame J-band shifts beyond the coverage of the deepest bandpasses at <5 μm< 5~\mu m (typically SpitzerSpitzer/IRAC 4.5 μm\mu m or future JWSTJWST/NIRCam observations). We demonstrate that (ugi)s(ugi)_s offers improvements to UVJUVJ at z>3z>3, and can be applied to galaxies in the JWSTJWST era. We apply (ugi)s(ugi)_s selection to galaxies at 0.5<z<60.5<z<6 from the (observed) 3D-HST and UltraVISTA catalogs, and to the (simulated) JAGUAR catalogs. We show that extrapolation can affect (VJ)0(V-J)_0 color by up to 1 magnitude, but changes (usis)0(u_s-i_s)_0 color by \leq 0.2 mag, even at z6z\simeq 6. While (ugi)s(ugi)_s-selected quiescent samples are comparable to UVJUVJ in completeness (both achieve \sim85-90% at z=33.5z=3-3.5), (ugi)s(ugi)_s reduces contamination in quiescent samples by nearly a factor of two, from \simeq35% to \simeq17% at z=3z=3, and from \simeq 60% to \simeq 33% at z=6z=6. This leads to improvements in the true-to-false-positive ratio (TP/FP), where we find TP/FP \gtrsim 2.2 for (ugi)s(ugi)_s at z3.56z \simeq 3.5 - 6, compared to TP/FP << 1 for UVJUVJ-selected samples. This indicates that contaminants will outnumber true quiescent galaxies in UVJUVJ at these redshifts, while (ugi)s(ugi)_s will provide higher-fidelity samples.Comment: Submitted to Ap

    A massive, quiescent galaxy at redshift of z=3.717

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    In the early Universe finding massive galaxies that have stopped forming stars present an observational challenge as their rest-frame ultraviolet emission is negligible and they can only be reliably identified by extremely deep near-infrared surveys. These have revealed the presence of massive, quiescent early-type galaxies appearing in the universe as early as z\sim2, an epoch 3 Gyr after the Big Bang. Their age and formation processes have now been explained by an improved generation of galaxy formation models where they form rapidly at z\sim3-4, consistent with the typical masses and ages derived from their observations. Deeper surveys have now reported evidence for populations of massive, quiescent galaxies at even higher redshifts and earlier times, however the evidence for their existence, and redshift, has relied entirely on coarsely sampled photometry. These early massive, quiescent galaxies are not predicted by the latest generation of theoretical models. Here, we report the spectroscopic confirmation of one of these galaxies at redshift z=3.717 with a stellar mass of 1.7×\times1011^{11} M_\odot whose absorption line spectrum shows no current star-formation and which has a derived age of nearly half the age of the Universe at this redshift. The observations demonstrates that the galaxy must have quickly formed the majority of its stars within the first billion years of cosmic history in an extreme and short starburst. This ancestral event is similar to those starting to be found by sub-mm wavelength surveys pointing to a possible connection between these two populations. Early formation of such massive systems is likely to require significant revisions to our picture of early galaxy assembly.Comment: 6 pages, 7 figures. This is the final preprint corresponding closely to the published version. Uploaded 6 months after publication in accordance with Nature polic

    Exploration of wheat and pathogen transcriptomes during tan spot infection

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    Objectives: The fungus Pyrenophora tritici-repentis is the causal agent of tan spot, a major disease of wheat (Triticum aestivum). Here, we used RNA sequencing to generate transcriptional datasets for both the host and pathogen during infection and during in vitro pathogen growth stages. Data description: To capture gene expression during wheat infection with the P. tritici-repentis isolate M4, RNA datasets were generated for wheat inoculated with P. tritici-repentis (infection) and a mock (control) at 3 and 4 days post-infection, when scorable leaf disease symptoms manifest. The P. tritici-repentis isolate M4 was also RNA sequenced to capture gene expression in vitro at two different growth stages: 7-day old vegetative mycelia and 9-day old sporulating mycelia, to coincide with a latent growth stage and early sporulation respectively. In total, 6 RNA datasets are available to aid in the validation of predicted genes of P. tritici-repentis and wheat. The datasets generated offer an insight into the transcriptomic profile of the host-pathogen interaction and can be used to investigate the expression of a subset of transcripts or targeted genes prior to designing cost-intensive RNA sequencing experiments, that would be best further explored with replication and a time series analysis
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