Childhood emotional trauma and cyberbullying perpetration among emerging adults: a multiple mediation model of the role of problematic social media use and psychopathology

Research suggests that a small minority of social media users experience problems as a result of their online use. The purpose of the present study was to examine the association of cyberbullying perpetration and problematic social media use with childhood emotional trauma, Cluster B (narcissistic, histrionic, antisocial, and borderline) personality traits, dissociative experiences (DEs), depression, and self-esteem in a nonclinical undergraduate sample. A total of 344 university students volunteered to complete a questionnaire that included measures on the aforementioned dimensions. Thirty-eight percent of the participants had emotional neglect and 27% had emotional abuse, while 44% of them demonstrated at least one cyberbullying perpetration behavior. Results indicated that cyberbullying perpetrators had higher scores on problematic social media use, dissociative experiences, Cluster B traits, depression and childhood emotional trauma, and lower on self-esteem. Path analysis demonstrated that, while adjusting for gender and age, childhood emotional trauma was directly and indirectly associated with cyberbullying perpetration via Cluster B traits. Moreover, depression and dissociation were directly associated with problematic social media use. The findings of this study emphasize the important direct role of childhood emotional trauma and pathological personality traits on cyberbullying perpetration

Anuran responses to spatial patterns of agricultural landscapes in Argentina

Context: Amphibians are declining worldwide and land use change to agriculture is recognized as a leading cause. Argentina is undergoing an agriculturalization process with rapid changes in landscape structure. Objectives: We evaluated anuran response to landscape composition and configuration in two landscapes of east-central Argentina with different degrees of agriculturalization. We identified sensitive species and evaluated landscape influence on communities and individual species at two spatial scales. Methods: We compared anuran richness, frequency of occurrence, and activity between landscapes using call surveys data from 120 sampling points from 2007 to 2009. We evaluated anuran responses to landscape structure variables estimated within 250 and 500-m radius buffers using canonical correspondence analysis and multimodel inference from a set of candidate models. Results: Anuran richness was lower in the landscape with greater level of agriculturalization with reduced amount of forest cover and stream length. This pattern was driven by the lower occurrence and calling activity of seven out of the sixteen recorded species. Four species responded positively to the amount of forest cover and stream habitat. Three species responded positively to forest cohesion and negatively to rural housing. Two responded negatively to crop area and diversity of cover classes. Conclusions: Anurans within agricultural landscapes of east-central Argentina are responding to landscape structure. Responses varied depending on species and study scale. Life-history traits contribute to responses differences. Our study offers a better understanding of landscape effects on anurans and can be used for land management in other areas experiencing a similar agriculturalization process.Facultad de Ciencias ExactasCentro de Investigaciones del Medioambient

Effects of different feeding time and frequency on metabolic conditions and milk production in heat-stressed dairy cows

The aim of this paper was to evaluate the effects of three different feeding management (FM) schedules on physiological markers of heat stress (HS), metabolic conditions, milk yield and quality during hot season in dairy cows. The study involved 27 mid-lactating cows, subdivided in 3 homogeneous groups differing for feeding time and frequency: total mixed ration (TMR) delivered once daily in the morning (M); twice daily, half in the morning and half in the evening (ME); once daily in the evening (E). During the trial blood samples were collected in the morning (a.m.) and in the evening (p.m.), breathing rate (BR), rectal temperature (RT), and milk yield were recorded and individual milk samples were collected. Microclimate data indicated that cows were subjected to mild-moderate HS. During the hotter days, cows in M treatment showed higher values of RT (38.97 \ub0C vs. 38.68 \ub0C and 38.62 \ub0C, in ME and E) and BR (71.44 vs. 66.52 and 65.26 breaths min-1, in ME and E), a.m. plasma glucose was lower in M (3.69 vs. 3.83 and 3.83 mmol L-1, in ME and E) and a.m. plasma urea was lower in E (4.82 vs. 5.48 and 5.35 mmol L-1, in M and ME). Milk yield was unaffected by FM, as well as milk composition and cheese-making properties. Only milk protein content and yield were higher in M (3.42 vs. 3.36 and 3.27%; and 1.11 vs 1.08 and 1.02 kg d-1, for ME and E). Our results on cow physiology indicate how M seems the less suitable FM to match cow welfare during the summer season

Evidence for a decline of PCBs and PAHs in rural vegetation and air in the United Kingdom.

RELIABLE data on persistent organic contaminants in the environment are needed to evaluate strategies to limit their dispersal. Long-term data are often not available, however, because the chemicals in question were not routinely analysed in the past. Although attempts have been made to assess temporal trends by analysis of environmental samples deposited in discrete or identifiable layers (in sediment or peat cores)1–3, these media may be disturbed in situ or give poor temporal resolution, or the contaminants may be subject to post-depositional changes. Polychlorinated biphenyls (PCBs) and polyaromatic hydrocarbons (PAHs) are persistent and toxic4–9 contaminants for which no long-term global ambient monitoring data exist. Plant foliage is a reliable monitor of ambient levels of vapour-phase compounds in air10–16 and here we present an analysis of archived herbage samples (1965–89) which shows that air concentrations of lower chlorinated PCBs in rural England have decreased by up to a factor of 50 between 1965–69 and 1985–89. High-molecular-weight PCBs and PAHs have also decreased in concentration, but not to such a great extent