584 research outputs found

    Evidence of very low metallicity and high ionization state in a strongly lensed, star-forming dwarf galaxy at z=3.417

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    We investigate the gas-phase metallicity and Lyman Continuum (LyC) escape fraction of a strongly gravitationally lensed, extreme emission-line galaxy at z=3.417, J1000+0221S, recently discovered by the CANDELS team. We derive ionization and metallicity sensitive emission-line ratios from H+K band LBT/LUCI medium resolution spectroscopy. J1000+0221S shows high ionization conditions, as evidenced by its enhanced [OIII]/[OII] and [OIII]/Hbeta ratios. Consistently, strong-line methods based on the available line ratios suggest that J1000+0221S is an extremely metal-poor galaxy, with a metallicity of 12+log(O/H) < 7.44 (< 5% solar), placing it among the most metal-poor star-forming galaxies at z > 3 discovered so far. In combination with its low stellar mass (2x10^8 Msun) and high star formation rate (5 Msun/yr), the metallicity of J1000+0221S is consistent with the extrapolation to low masses of the mass-metallicity relation traced by Lyman-break galaxies at z > 3, but it is 0.55 dex lower than predicted by the fundamental metallicity relation at z < 2.5. These observations suggest the picture of a rapidly growing galaxy, possibly fed by the massive accretion of pristine gas. Additionally, deep LBT/LBC in the UGR bands are used to derive a limit to the LyC escape fraction, thus allowing us to explore for the first time the regime of sub-L* galaxies at z > 3. We find a 1sigma upper limit to the escape fraction of 23%, which adds a new observational constraint to recent theoretical models predicting that sub-L* galaxies at high-z have high escape fractions and thus are the responsible for the reioization of the Universe.Comment: 5 pages, 3 figures and 1 table. Accepted for publication in ApJ Letter

    Body composition changes after covering on foot the Way of Saint James

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    Con este estudio, se pretende comprobar la existencia de cambios y variaciones en la composición corporal de un grupo de adultos después de la realización a pie de 5 etapas del Camino Primitivo de Santiago de Compostela que discurre por la Provincia de Lugo. En él participaron 22 personas de edades comprendidas entre los 21 y los 48 años, siendo el 22,72% varones y el 77,27% mujeres. Se realizaron medidas de bioimpedancia eléctrica con la TANITA BC-418 en dos momentos diferentes (antes y después de realizar las etapas del Camino de Santiago). Las modificaciones de las diferentes variables medidas se analizaron y trataron con el paquete estadístico SPSS 20.0. Los resultados encontrados muestran que con este tipo de trabajo aeróbico y esta duración, en cierta medida se modificó la composición corporal de los sujetos participantes. Sin embargo, se propone que para futuros estudios el tiempo de trabajo sea mayor y que la intensidad varíe, con el fin de comprobar si se obtienen más resultados significativosWith this research, we want to check body composition changes and variations in a group of adults after covering on foot 5 stages of the Primitive Way of Saint James, which runs through the Lugo province. This research involved 22 people between 21-48 years-old, 22.72% males and 77.27% females. Measurements were performed with the bio-impedance TANITA BC-418 at two different moments (before and after covering the Saint James` Way stages). Changes in different measured variables were analyzed and treated with the SPSS Statistics 20.0. Results show that, with this type of aerobic work and this duration, body composition of people involved had some changes. However, it is propose to increase work time and to vary intensity in future researches, with the intention of prove if more significant results are obtainedS

    Discovery of a Quadruple Lens in CANDELS with a Record Lens Redshift z=1.53

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    Using spectroscopy from the Large Binocular Telescope and imaging from the Hubble Space Telescope we discovered the first strong galaxy lens at z(lens)>1. The lens has a secure photometric redshift of z=1.53+/-0.09 and the source is spectroscopically confirmed at z=3.417. The Einstein radius (0.35"; 3.0 kpc) encloses 7.6 x 10^10 Msol, with an upper limit on the dark matter fraction of 60%. The highly magnified (40x) source galaxy has a very small stellar mass (~10^8 Msol) and shows an extremely strong [OIII]_5007A emission line (EW_0 ~ 1000A) bolstering the evidence that intense starbursts among very low-mass galaxies are common at high redshift.Comment: accepted for publication in ApJ Letter

    Characteristics of a Microcystin-Degrading Bacterium under Alkaline Environmental Conditions

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    The pH of the water associated with toxic blooms of cyanobacteria is typically in the alkaline range; however, previously only microcystin-degrading bacteria growing in neutral pH conditions have been isolated. Therefore, we sought to isolate and characterize an alkali-tolerant microcystin-degrading bacterium from a water bloom using microcystin-LR. Analysis of the 16S rRNA gene sequence revealed that the isolated bacterium belonged to the genus Sphingopyxis, and the strain was named C-1. Sphingopyxis sp. C-1 can grow; at pH 11.0; however, the optimum pH for growth was pH 7.0. The microcystin degradation activity of the bacterium was the greatest between pH 6.52 and pH 8.45 but was also detected at pH 10.0. The mlrA homolog encoding the microcystin-degrading enzyme in the C-1 strain was conserved. We concluded that alkali-tolerant microcystin-degrading bacterium played a key role in triggering the rapid degradation of microcystin, leading to the disappearance of toxic water blooms in aquatic environments

    Pain as a mediator in the temperament-alexithymia relationship in individuals suffering from rheumatoid arthritis

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    [Abstract] OBJECTIVE: The study aims to establish a relationship between temperament traits, symptoms of alexithymia, and pain intensity in rheumatoid arthritis. Despite the significant progress seen in the area of RA treatment, pain, often life-long, remains the predominant symptom. This constant pain and progressing disability, as well as dependence upon other people cause RA patients to experience psychological stress that can be modified by individual patient traits. Recently, several authors have underlined the need to relate personality and temperament constructs to neurobiological processes that may underlie individual differences. It seems then that patient characteristics may play a significant role in the course of the disease. PATIENTS AND METHODS: The study was performed on a group of patients (N=317) with rheumatoid arthritis diagnosed according to the current criteria of the American-European Consensus of 2010. All patients expressed voluntary consent to participate, and the study protocol was approved by the Local Ethics Committee. This was a survey-based study. It involved the application of the adult version of the Buss and Plomin EAS Temperament Questionnaire (EAS-D), which tests 3 main temperament domains: sociability, activity, and emotionality. The pain was measured on the Visual Analogue Scale (VAS). VAS is used to measure pain intensity. The level of alexithymia was tested using the Toronto Alexithymia Scale-20. The scale consists of 20 statements and includes 3 subscales that measure difficulty in describing feelings/emotions, difficulty in identifying feelings/emotions, and operational externally oriented thinking. RESULTS: The analysis revealed that alexithymia is positively correlated only with one dimension of temperament, i.e., emotionality, and with pain intensity. Moreover, high emotionality was positively correlated with pain. A simple mediation analysis revealed that pain intensity functioned as a mediator in the emotionality-alexithymia relationship. CONCLUSIONS: The observed correlations indicate that RA patients with a high level of emotionality exhibit high alexithymia as they perceive pain related to the disease symptoms more intensely. The observed mediation is partial, meaning that there are also other mediating factors in this relationship

    Boards of directors in SMEs: An empirical evidence of board task performance

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    This paper seeks to provide a better understanding of what makes boards effective. We analyse the relationships between board demography and company performance and between working structures and board tasks in small and medium-sized enterprises (SMEs). We test our hypotheses on a sample of 307 Spanish SMEs. The main empirical result is the negative impact that the proportion of outside directors and the board size have on firm performance. We also find a negative impact of outsiders’ presence and a positive impact of director tenure on the board’s service role. Our analysis of the role of board control highlights the negative relationship between this variable and CEO tenure

    Prevalence of and Risk Factors for Biliary Carriage of Bacteria Showing Worrisome and Unexpected Resistance Traits

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    Data on biliary carriage of bacteria and, specifically, of bacteria with worrisome and unexpected resistance traits (URB) are lacking. A prospective study (April 2010 to December 2011) was performed that included all patients admitted for<48 h for elective laparoscopic cholecystectomy in a Spanish hospital. Bile samples were cultured and epidemiological/clinical data recorded. Logistic regression models (stepwise) were performed using bactobilia or bactobilia by URB as dependent variables. Models (P< 0.001) showing the highest R2 values were considered. A total of 198 patients (40.4% males; age, 55.3 17.3 years) were included. Bactobilia was found in 44 of them (22.2%). The presence of bactobilia was associated (R2 Cox, 0.30) with previous biliary endoscopic retrograde cholangiopancreatography (ERCP) (odds ratio [OR], 8.95; 95% confidence interval [CI], 2.96 to 27.06; P< 0.001), previous admission (OR, 2.82; 95% CI, 1.10 to 7.24; P 0.031), and age (OR, 1.09 per year; 95% CI, 1.05 to 1.12; P< 0.001). Ten out of the 44 (22.7%) patients with bactobilia carried URB: 1 Escherichia coli isolate (CTX-M), 1 Klebsiella pneumoniae isolate (OXA-48), 3 high-level gentamicin-resistant enterococci, 1 vancomycin-resistant Enterococcus isolate, 3 Enterobacter cloacae strains, and 1 imipenem-resistant Pseudomonas aeruginosa strain. Bactobilia by URB (versus those by non-URB) was only associated (R2 Cox, 0.19) with previous ERCP (OR, 11.11; 95% CI, 1.98 to 62.47; P 0.006). For analyses of patients with bactobilia by URB versus the remaining patients, previous ERCP (OR, 35.284; 95% CI, 5.320 to 234.016; P<0.001), previous intake of antibiotics (OR, 7.200; 95% CI, 0.962 to 53.906; P 0.050), and age (OR, 1.113 per year of age; 95% CI, 1.028 to 1.206; P 0.009) were associated with bactobilia by URB (R2 Cox, 0.19; P<0.001). Previous antibiotic exposure (in addition to age and previous ERCP) was a risk driver for bactobilia by URB. This may have implications in prophylactic/therapeutic measures

    3D-HST+CANDELS : the evolution of the galaxy size-mass distribution since z=3

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    Spectroscopic+photometric redshifts, stellar mass estimates, and rest-frame colors from the 3D-HST survey are combined with structural parameter measurements from CANDELS imaging to determine the galaxy size-mass distribution over the redshift range 0 < z < 3. Separating early- and late-type galaxies on the basis of star-formation activity, we confirm that early-type galaxies are on average smaller than late-type galaxies at all redshifts, and we find a significantly different rate of average size evolution at fixed galaxy mass, with fast evolution for the early-type population, R eff∝(1 + z)–1.48, and moderate evolution for the late-type population, R eff∝(1 + z)-0.75Peer reviewedFinal Accepted Versio
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