16,527 research outputs found

    Multichromatic colour-magnitude diagrams of the globular cluster NGC 6366

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    We present multichromatic isochrone fits to the colour-magnitude data of the globular cluster NGC 6366, based on Hubble Space Telescope Advanced Camera for Surveys/Wide Field Channel and Southern Astrophysical Research photometric data. We corrected the photometric data for differential reddening and calculated the mean ridge line of the colour-magnitude diagrams. We compared the isochrones of Dartmouth Stellar Evolution Database and PAdova and TRieste Stellar Evolution Code both with microscopic diffusion starting on the main sequence. Bracketing all previous determinations of this cluster, we tested metallicities from [Fe/H]=-1.00 to [Fe/H]=-0.50, and ages from 9 to 13 Gyr. After determining the total to selective extinction ratio only from stars belonging to this cluster, R_V=3.06+/-0.14, we found the parameters for this cluster to be E(B-V)=0.69+/-0.02(int)+/-0.04(ext), (m-M)_V=15.02+/-0.07(int)+/-0.13(ext), Age=11+/-1.15 Gyr. Evolutionary models fail to reproduce the low-Teff sequence in multiband colour-magnitude diagrams, indicating that they still have an incomplete physics. We found that the Dartmouth Stellar Evolution Database isochrones better fit the subgiant branch and low main sequence than the PAdova and TRieste Stellar Evolution Code.Comment: 9 pages, 5 figure

    Factors associated with postharvest ripening heterogeneity of "Hass" avocados (Persea americana Mill)

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    Indexación: Web of ScienceIntroduction. 'Hass' is the main avocado cultivar commercialized worldwide. The extended flowering period, very low percentage of fruit set and inability to ripen on the tree renders the fruit heterogeneous and unpredictable during postharvest management. The "triggered" and "ready-to-eat" growing markets for 'Hass' avocados are affected by the variable postharvest ripening or ripening heterogeneity which creates severe logistical problems for marketers and inconsistent quality delivery to consumers. Synthesis. The dry matter content, the current avocado harvest index that correlates very well with oil content, has been extensively used to harvest 'Hass' avocados to comply with the minimum standards to guarantee consumer satisfaction. However, previous work and empirical experience demonstrate that dry matter does not correlate on a fruit-to-fruit basis with time to reach edible ripeness. Thus, avocados of very different ages are harvested from individual trees, resulting in heterogeneous postharvest ripening of fruit within a specific batch. Several preharvest factors related to environmental and growing conditions and crop management as well as postharvest technology strategies influence the observed variability of postharvest ripening. Conclusion. Modern approaches based on studying the composition of individual fruits displaying contrasting postharvest ripening behavior, combined with non-destructive phenotyping techniques, seem to offer practical solutions for the fresh supply chain of avocados to sort fruit based on their ripening capacity.http://www.pubhort.org/fruits/2016/5/fruits160045.ht

    Personality styles and defense mechanisms in a community sample of adolescents: An exploratory study

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    This study aimed to test if the preference for using certain types of defense mechanisms, according to Ihilevich and Gleser’s (1969, 1986) perspective, is associated with personality styles, proposed by Millon (1993), and also, aimed to test if both constructs give a contribution to the identification of global types of psychological functioning in adolescents. Eight hundred and thirty adolescents, ranging in age from 14 to 19 years (M = 16.64, SD = 1.9) participated in the study. The Portuguese versions of the Defense Mechanisms Inventory for Adolescents and the Millon Adolescents Clinical Inventory were administered. Multiple linear regression analysis and principal component analysis were computed. Results demonstrate an association between defense mechanisms and personality styles and both constructs contribute to the identification of two types of psychological functioning in adolescents: an internalizing type and an externalizing type

    Critical phenomena of thick branes in warped spacetimes

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    We have investigated the effects of a generic bulk first-order phase transition on thick Minkowski branes in warped geometries. As occurs in Euclidean space, when the system is brought near the phase transition an interface separating two ordered phases splits into two interfaces with a disordered phase in between. A remarkable and distinctive feature is that the critical temperature of the phase transition is lowered due to pure geometrical effects. We have studied a variety of critical exponents and the evolution of the transverse-traceless sector of the metric fluctuations.Comment: revtex4, 4 pages, 4 figures, some comments added, typos corrected, published in PR

    Testing Models Relating Rejection, Depression, Interpersonal Needs, and Psychache to Suicide Risk in Nonclinical Individuals

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    Objectives: Using structural equation modeling, we tested a primary model of suicide risk and 3 competing, alternative models based on 4 psychological variables deemed important in the literature (perception of parental rejection, depression, interpersonal needs comprising perceived burdensomeness and thwarted belongingness, and psychache), in a nonclinical sample of Portuguese adults. Method: A convenience sample of 203 adults (100men, 103women; aged18–65 years) participated in this study. Results: Analyses demonstrated that the proposed primary model had the best fit to the observed data. The differences in fit indexes for this model and one of the alternative models, however, were not substantial. Conclusion: Perceived parental rejection related directly to suicide risk and indirectly via depression and interpersonal needs. Depression linked indirectly to suicide risk via interpersonal needs and psychache. Interpersonal needs related directly to suicide risk and indirectly via psychache, which related directly to suicide risk

    Suicide risk in a Portuguese non-clinical sample of adults

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    Background and Objectives: This exploratory study simultaneously tests the contribution of socio-demographic, clinical, distress, and personality variables for identifying suicide risk in a non-clinical sample. Methods: A convenience sample of 810 adults ranging in age from 19 to 67 years (M = 36.34, SD = 12.46) and living in various Portuguese regions participated. Their education varied from 6 to 21 years of schooling (M = 11.74, SD = 5.14). Participants responded to sociodemographic questions, the Depressive Experiences Questionnaire, the Center for the Epidemiological Studies of Depression Scale, and the Suicide Behaviors Questionnaire-Revised. Results: In the present sample, 4.3% of participants indicated past suicide attempts, 27.9% reported some lifetime suicide ideation, and 6.4% indicated a past suicide plan. Depressive symptoms, having seen a psychologist or psychiatrist, self-criticism, and education discriminated between participants who had attempted suicide (n = 35) and those who had not attempted to die by suicide (n = 775). Depressive symptoms, having seen a psychologist or psychiatrist, self-criticism, psychiatric disease and age discriminated between participants who scored below (n = 650) and who scored equal to or above (n = 160) the cut-off score for the Suicide Behaviors Questionnaire-Revised. Conclusions: Results have implications for the assessment of suicide risk

    Effect of flocculation and sedimentation times on the removal of polystyrene microplastics from water

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    A novel high-throughput analytical method to quantify microplastics in water by flow cytometry

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    Microplastics (MPs) are pervasive contaminants with unclear toxicological impacts. Current research on MP pollution relies on low-throughput methodologies, which are time-consuming and cannot directly measure MP concentration in suspensions. This study presents a qualitative and quantitative flow cytometry-based method for analysing MPs in water, offering a faster and more sustainable alternative. The method involves density separation to remove interfering particles, UV irradiation to eliminate microorganisms, and filtration to remove particles above 100 µm. The sensitivity of the method for different types of MPs, such as polystyrene (PS), polypropylene (PP), polyvinyl chloride (PVC), polyethylene terephthalate (PET), and polyamide (PA) microbeads, ranges from 2 µg/L to 1 mg/L. For these MPs, good linearity was found in matrix-matched calibration where the most concentrated standard was 5 mg/L (R2 0.9820–0.9989) although the linear range can be larger (e.g. 42 mg MP/L for PS microbeads). The repeatability and reproducibility of the method for the model PS MP were <17.0% and 8.5%, respectively. The sample treatment method consisting of density separation and UV pretreatment, when carried out independently, led to 95.0% and 93.4% recoveries. The overall trueness of the optimized method for various sizes and compositions of microbeads is about 97%, according to validation supported by microscopy analysis. This method can substitute the traditional quantitative analytical approach based on counting microbeads with microscopy
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