Constraints on feedback processes during the formation of early-type galaxies

Galaxies are found to obey scaling relations between a number of observables. These relations follow different trends at the low- and the high-mass ends. The processes driving the curvature of scaling relations remain uncertain. In this letter, we focus on the specific family of early-type galaxies, deriving the star formation histories of a complete sample of visually classified galaxies from SDSS-DR7 over the redshift range 0.01<z<0.025, covering a stellar mass interval from 10^9 to 3 x 10^11 Msun. Our sample features the characteristic "knee" in the surface brightness vs. mass distribution at Mstar~3 x 10^10 Msun. We find a clear difference between the age and metallicity distributions of the stellar populations above and beyond this knee, which suggests a sudden transition from a constant, highly efficient mode of star formation in high-mass galaxies, gradually decreasing towards the low-mass end of the sample. At fixed mass, our early-type sample is more efficient in building up the stellar content at early times in comparison to the general population of galaxies, with half of the stars already in place by redshift z~2 for all masses. The metallicity-age trend in low-mass galaxies is not compatible with infall of metal-poor gas, suggesting instead an outflow-driven relation.Comment: 12 pages,3 figures, accepted for publication in ApJ

Expressão de Marcadores de Qualidade Seminal e Fertilidade de Garanhões da Raça Crioula.

Background: Mammalian spermatozoa contain a complex RNA population able to regulate spermatogenesis and play a role in the fertilization process. However, little is known about genetic factors and their role in fertility. Discovering novel molecular markers is necessary because semen quality parameters and routine exams still fail at detecting cases of subfertility.  The objective of this study was to assess the relationship between the expression of the genes SPA17, TNF and TIMP2 by spermatozoa and semen quality, fertility, and motility parameters of sperm cells after thawing in stallions of the Crioulo breed. Materials, Methods &amp; Results: Analysis were performed on ejaculates from 40 stallions whose fertility was evaluated by checking their reproductive history, considering 30 inseminations for each animal. One mL of each ejaculate was reserved for fresh semen analysis, and the remaining volume was split into 2 samples; 1 of these samples was stored for gene expression analysis, and the other was cryopreserved. Sperm cell motility was analyzed using the computer-assisted semen analysis system. Sperm pathology analyses, hypoosmotic tests, and fluorescence tests were also performed. For gene expression analysis, mRNA was extracted for quantitation of expression of genes of interest by quantitative real-time polymerase chain reaction (qPCR). The results from qPCR assays were determined using an absolute standard curve [formula=10^(target ct - standard CT)/slope]. Statistical analysis was performed using Pearson correlation. Expression of SPA17 was positively correlated with functional integrity of the plasma membrane (r = 0.602; P = 0.004), structural integrity of the plasma membrane (r = 0.590; P = 0.004), conception rate (r = 0.454; P = 0,007), and total motility (r = 0.522; P = 0.001); it was negatively correlated with immobile sperm cells (r = -0.558; P = 0.006), and sperm cells with major defects (r = 0.4907; P = 0.012). Expression of TNF in sperm cells thawed after cryopreservation was positively correlated with curvilinear velocity (VCL) [r = 0.5147; P = 0.02], straight-line velocity (VSL) [r = 0.4714; P = 0.03], and average path velocity (VAP) [r = 0.4907; P = 0.02]. A positive correlation between TIMP2 expression and beat-cross frequency (BCF) was found [r = 0.408; P = 0.02]. Discussion: The positive correlations between SPA17 expression and the parameters total motility and conception rate may be related to the previously reported interaction of SPA17 with the zona pellucida, which facilitates penetration of the sperm cell into the oocyte. The positive correlations between expression of SPA17 and the parameters structural integrity of the plasma membrane and functionality of the plasma membrane are connected to characteristics important for viability of the sperm cell at the moment of conception, such as avoiding thermal shock and maintaining fluidity of the plasma membrane. Expression of TNF was positively correlated with sperm cell velocities after cryopreservation. TNF exerts a series of biological activities in different cell types. TNF regulates energy metabolism, especially in lipid homeostasis; it can be involved with plasma membrane phospholipid metabolism and reduce damage to the sperm cell during the cryopreservation process. We conclude that expression of SPA17 in equine sperm cells can be used as a biomarker for semen quality and fertility of stallions, while expression of TIMP2 can be used as a biomarker for beat-cross frequency. Expression of TNF was associated with better sperm cell survival rates after the cryopreservation process. Keywords: stallion, fertility, concept rate, seminal quality, expression gene. Título: Expressão de marcadores de qualidade seminal e fertilidade de garanhões da raça Crioula Descritores: garanhão, fertilidade, taxa de prenhez, qualidade seminal, expressão gênica.Background: Mammalian spermatozoa contain a complex RNA population able to regulate spermatogenesis and play a role in the fertilization process. However, little is known about genetic factors and their role in fertility. Discovering novel molecular markers is necessary because semen quality parameters and routine exams still fail at detecting cases of subfertility. &nbsp;The objective of this study was to assess the relationship between the expression of the genes SPA17,TNF and TIMP2 by spermatozoa and sêmen quality, fertility, and motility parameters of sperm cells after thawing in stallions of the Crioulo breed. Materials, Methods &amp; Results: Analyses were performed on ejaculates from 40 stallions whose fertility was evaluated by checking their reproductive history, considering 30 inseminations for each animal. One mL of each ejaculate was reserved for fresh semen analysis, and the remaining volume was split into two samples; one of these samples was stored for gene expression analysis, and the other was cryopreserved. Sperm cell motility was analyzed using the AndroVision® computer-aided sperm analysis (CASA) system. Sperm pathology analyses, hypoosmotic tests, and fluorescence tests were also performed. For gene expression analysis, mRNA was extracted for quantitation of expression of genes of interest by quantitative real-time polymerase chain reaction (qPCR). The results from qPCR assays were determined using an absolute standard curve (formula=10^((target ct – standard CT)/slope). Statistical analysis was performed using Pearson correlation. Expression of SPA17 was positively correlated with functional integrity of the plasma membrane (r=0.602; p&lt;0.004), structural integrity of the plasma membrane (r=0.590; p&lt;0.004), conception rate (r=0.454; p&lt;0,007), and total motility (r=0,522;p&lt;0,001); it was negatively correlated with immobile sperm cells (r=-0.558; p&lt;0.006), and sperm cells with major defects (r=0.4907; p&lt;0.012). Expression of TNF in sperm cells thawed after cryopreservation was positively correlated with curvilinear velocity (VCL) (r=0.5147; p&lt;0.02), straight-line velocity (VSL) (r=0.4714; p&lt;0.03), and average path velocity (VAP) (r=0.4907; p&lt;0.02). A positive correlation between TIMP2 expression and beat-cross frequency (BCF) was found (r=0.408; p&lt;0.02). Discussion: The positive correlations between SPA17 expression and the parameters total motility and conception rate may be related to the previously reported interaction of SPA17 with the zona pellucida, which facilitates penetration of the sperm cell into the oocyte. The positive correlations between expression of SPA17 and the parameters structural integrity of the plasma membrane and functionality of the plasma membrane are connected to characteristics important for viability of the sperm cell at the moment of conception, such as avoiding thermal shock and maintaining fluidity of the plasma membrane. Expression of TNF was positively correlated with sperm cell velocities after cryopreservation. TNF exerts a series of biological activities in different cell types. TNF regulates energy metabolism, especially in lipid homeostasis; it can be involved with plasma membrane phospholipid metabolism and reduce damage to the sperm cell during the cryopreservation process. We conclude that expression of SPA17 in equine sperm cells can be used as a biomarker for semen quality and fertility of stallions, while expression of TIMP2 can be used as a biomarker for beat-cross frequency. Expression of TNF was associated with better sperm cell survival rates after the cryopreservation process

Segregation Effects According to the Evolutionary Stage of Galaxy Groups

We study segregation phenomena in 57 groups selected from the 2PIGG catalog of galaxy groups. The sample corresponds to those systems located in areas of at least 80% redshift coverage out to 10 times the radius of the groups. The dynamical state of the galaxy systems was determined after studying their velocity distributions. We have used the Anderson-Darling test to distinguish relaxed and non-relaxed systems. This analysis indicates that 84% of groups have galaxy velocities consistent with the normal distribution, while 16% of them have more complex underlying distributions. Properties of the member galaxies are investigated taking into account this classification. Our results indicate that galaxies in Gaussian groups are significantly more evolved than galaxies in non-relaxed systems out to distances of about 4R200, presenting signficantly redder (B-R) color. We also find evidence that galaxies with M_R < -21.5 in Gaussian groups are closer to the condition of energy equipartition.Comment: 5 pages, 4 figures, accepted for publication in the MNRAS Letter

Efficacy and tolerability of a gatifloxacin/prednisolone acetate fixed combination for topical prophylaxis and control of inflammation in phacoemulsification: a 20-day-double-blind comparison to its individual components

OBJECTIVE: To compare the efficacy and tolerability of a fixed combination of 0.3% gatifloxacin and 1% prednisolone (Zypred®) versus the individual components used separately (Zypred® and Predfort®) for infection prophylaxis and inflammation control after cataract surgery with intraocular lens implantation. METHODS: A prospective, randomized, double-blind, parallel-group study of 108 patients who underwent phacoemulsification and intraocular lens implantation was conducted. After random assignment, 47 eyes received the fixed combination of topical 0.3% gatifloxacin/1% prednisolone drops, and 61 eyes received the same doses of the individual components as separate solutions four times a day for 15 days. Baseline and postoperative assessments were made on postoperative days 1, 7, 15, and 20. RESULTS: All objective (best corrected visual acuity, sign of active ocular inflammation, central and incisional corneal edema, the number of cells per high-power field in the anterior chamber, and intraocular pressure) and subjective (eye pain, photophobia, burning sensation, itching, and foreign body sensation) criteria of efficacy were similar in both groups, with no significant differences. Group I included 47 eyes that received the fixed combination of gatifloxacin/prednisolone acetate eye drops and a placebo eye drop solution. Group II included 61 eyes that were treated with 0.3% gatifloxacin and 1% prednisolone acetate eye drops separately. The intraocular pressure was slightly higher in Group II (

Decision Tree Classifiers for Star/Galaxy Separation

We study the star/galaxy classification efficiency of 13 different decision tree algorithms applied to photometric objects in the Sloan Digital Sky Survey Data Release Seven (SDSS DR7). Each algorithm is defined by a set of parameters which, when varied, produce different final classification trees. We extensively explore the parameter space of each algorithm, using the set of $884,126$ SDSS objects with spectroscopic data as the training set. The efficiency of star-galaxy separation is measured using the completeness function. We find that the Functional Tree algorithm (FT) yields the best results as measured by the mean completeness in two magnitude intervals: $14\le r\le21$ ($85.2$) and $r\ge19$ ($82.1$). We compare the performance of the tree generated with the optimal FT configuration to the classifications provided by the SDSS parametric classifier, 2DPHOT and Ball et al. (2006). We find that our FT classifier is comparable or better in completeness over the full magnitude range $15\le r\le21$, with much lower contamination than all but the Ball et al. classifier. At the faintest magnitudes ($r>19$), our classifier is the only one able to maintain high completeness ($>$80%) while still achieving low contamination ($\sim2.5$). Finally, we apply our FT classifier to separate stars from galaxies in the full set of $69,545,326$ SDSS photometric objects in the magnitude range $14\le r\le21$.Comment: Submitted to A

Stellar Population Properties of ETGs in Compact Groups of Galaxies

We present results on the study of the stellar population in Early-Type galaxies (ETGs) belonging to 151 Compact Groups (CGs). We also selected a field sample composed of 846 ETGs to investigate environmental effects on galaxy evolution. We find that the dependences of mean stellar ages, [Z/H] and [$\alpha$/Fe] on central stellar velocity dispersion are similar, regardless where the ETG resides, CGs or field. When compared to the sample of centrals and satellites from the literature, we find that ETGs in GCs behave similarly to centrals, especially those embedded in low-mass haloes ($M_{h} < 10^ {12.5}M_{\odot}$). Except for the low-mass limit, where field galaxies present a Starforming signature, not seen in CGs, the ionization agent of the gas in CG and field galaxies seem to be similar and due to hot, evolved low-mass stars. However, field ETGs present an excess of H$\alpha$ emission relative to ETGs in CGs. Additionally, we performed a dynamical analysis, which shows that CGs present a bimodality in the group velocity dispersion distribution - a high and low-$\sigma$ mode. Our results indicate that high-$\sigma$ groups have a smaller fraction of spirals, shorter crossing times, and a more luminous population of galaxies than the low $\sigma$ groups. It is important to emphasize that our findings point to a small environmental impact on galaxies located in CGs. The only evidence we find is the change in gas content, suggesting environmentally-driven gas loss.Comment: 21 pages, 18 Figure

Combined Before-and-After Workplace Intervention to Promote Healthy Lifestyles in Healthcare Workers (STI-VI Study): Short-Term Assessment

Health care workers (HCWs) are prone to a heavy psycho-physical workload. Health promotion programs can help prevent the onset of chronic and work-related diseases. The aim of the STI-VI 'before-and-after' study, with assessments scheduled at 6 and 12 months, was to improve the lifestyle of HCWs with at least one cardiovascular risk factor. A tailored motivational counseling intervention, focusing on dietary habits and physical activity (PA) was administered to 167 HCWs (53 males; 114 females). BMI, waist circumference, blood pressure, and cholesterol, triglyceride, and blood glucose levels were measured before and after the intervention. The 6-month results (total sample and by gender) showed a marked effect on lifestyle: PA improved (+121.2 MET, p = 0.01), and diets became more similar to the Mediterranean model (+0.8, p < 0.001). BMI dropped (-0.2, p < 0.03), and waist circumference improved even more (-2.5 cm; p < 0.001). Other variables improved significantly: total and LDL cholesterol (-12.8 and -9.4 mg/dL, p < 0.001); systolic and diastolic blood pressure (-4.4 and -2.5 mmHg, p < 0.001); blood glucose (-1.5 mg/dL, p = 0.05); and triglycerides (significant only in women), (-8.7 mg/dL, p = 0.008); but HDL cholesterol levels dropped too. If consolidated at 12 months, these results indicate that our intervention can help HCWs maintain a healthy lifestyle and work ability