154 research outputs found
Do I feel ill because I crave for work or do I crave for work because I feel ill? A longitudinal analysis of work craving, self-regulation, and health
Background The theory of work craving defines workaholism as a pathological work addiction which comprises: (a) obsessive–compulsive desire to work, (b) anticipation of self-worth compensatory incentives from working, (c) anticipation of reduction of negative emotions or withdrawal symptoms from working, and (d) neurotic perfectionism. Research has shown that workaholism is associated with adverse health outcomes. However, the antecedents of workaholism and the causal direction of the relationship with health have been largely neglected. Aims In the present longitudinal study, we expect that work craving is predicted by deficits in emotional self-regulation (i.e., low action orientation) and mediates the relationship between self-regulation deficits and symptoms of psychological distress. We expected work craving to have an effect on later psychological distress symptoms, but not psychological distress symptoms to have an effect on later work craving. Methods In a sample of 170 German employees, a half-longitudinal design using two times of measurement was implemented to specify the paths of two different structural equation models of mediation: (a) action orientation to later work craving and work craving to later psychological distress, and alternatively, (b) the temporal order of action orientation to later distress and distress to later work craving. Results Our data indicated that work craving partially mediated the relationship between self-regulation deficits and psychological distress, but psychological distress symptoms were not found to increase later work craving. Conclusions The presented longitudinal study indicates important mechanisms of work craving, especially by highlighting the influence of self-regulation deficits on work craving and, in turn, psychological distress
Drag och motdrag - Strategisk interaktion i Afghanistan 2001-2007
Det amerikanska anfallet mot Afghanistan 2001 lyckades på relativt kort tid tvinga den rådande talibanregimen från makten. Sju år senare vållar en revitaliserad och svårdefinierad upprorsrörelse den afghanska regeringen betydande problem. Denna uppsats syftar till att belysa denna problematik ur ett strategiskt perspektiv. I uppsatsen analyseras den strategiska interaktion som präglat konflikten åren 2001-2007 utifrån Ivan Arreguin-Tofts teori om asymmetriska krig. Den tillhandahåller även en introduktion till den pågående diskussionen om upprorsrörelsens ursprung och attribut. En diskussion som präglas av betydande oenighet. Undersökningen finner att teorin om strategisk interaktion lämpar sig väl som förklaring till utgången av det inledande kriget 2001-2002, som präglades av en likartad strategisk interaktion, men att bilden därefter blir mer oklar och att teorins roll behöver ifrågasättas när den skall appliceras på pågående insatser
I avsaknad av vägledning? En undersökning av den reglerade våldsanvändningen i moderna fredsfrämjande insatser
Sedan 1999 har antalet fredsfrämjande interventioner som fått tydliga mandat att aktivt skydda civilbefolkningen kraftigt ökat. Att använda militärt våld för humanitära syften är dock inte oproblematiskt. Denna uppsats undersöker den reglerade våldsanvändningen, i form av Rules of engagement, i moderna fredsfrämjande insatser med utgångspunkt ur frågan om beskydd för civila. Den undersöker, med hjälp av bl.a. offentliga dokument och en fallstudie om insatsen i Tchad 2008, hur dessa regler sätts och försöker dessutom utmynna om utformningen av ROE påverkats av frågan om beskydd. Konceptet med skydd av civila har ställt nya krav på fredsstyrkor idag, men denna undersökning visar bland annat att det inte är helt självklart hur denna uppgift skall förstås, då intervenerande nationer och organisationer ofta saknar tydliga verktyg för operationaliserandet av beskydd för civilbefolkningen. Vidare finner uppsatsen att själva utformandet av Rules of engagement spelar mindre roll än dess faktiska tolkning och fredsstyrkans kapacitet
A Search for Metal-poor Stars Pre-enriched by Pair-instability Supernovae I. A Pilot Study for Target Selection from Sloan Digital Sky Survey (SDSS)
We report on a pilot study on identifying metal-poor stars pre-enriched by
Pair-Instability Supernovae (PISNe). Very massive, first generation (Population
III) stars (140M\odot \leq M \leq 260M\odot) end their lives as PISNe, which
have been predicted by theories, but no relics of PISNe have been observed yet.
Among the distinct characteristics of the yields of PISN, as predicted by
theoretical calculations, are a strong odd-even effect, and a strong
overabundance of Ca with respect to iron and the Solar ratio. We use the latter
characteristic to identify metal-poor stars in the Galactic halo that have been
pre-enriched by PISN, by comparing metallicites derived from strong, co-added
Fe lines detected in low-resolution (i.e., R \sim 2000) spectra of the Sloan
Digital Sky Survey (SDSS), with metallicities determined by the SDSS Stellar
Parameters Pipeline (SSPP). The latter are based on the strength of the Ca II K
line and assumptions on the Ca/Fe abundance ratio. Stars are selected as
candidates if their metallicity derived from Fe lines is significantly lower
than the SSPP metallicities. In a sample of 12,300 stars for which SDSS
spectroscopy is available, we have identified 18 candidate stars. Higher
resolution and signal-to-noise ratio spectra of these candidates are being
obtained with the Very Large Telescope of the European Southern Observatory and
the XSHOOTER spectrograph, to determine their abundance patterns, and to verify
our selection method. We plan to apply our method to the data base of several
million stellar spectra to be acquired with the LAMOST telescope in the next
five years.Comment: Accepted by RA
Recommended from our members
Characterization and intercomparison of aerosol absorption photometers: Result of two intercomparison workshops
Absorption photometers for real time application have been available since the 1980s, but the use of filter-based instruments to derive information on aerosol properties (absorption coefficient and black carbon, BC) is still a matter of debate. Several workshops have been conducted to investigate the performance of individual instruments over the intervening years. Two workshops with large sets of aerosol absorption photometers were conducted in 2005 and 2007. The data from these instruments were corrected using existing methods before further analysis. The inter-comparison shows a large variation between the responses to absorbing aerosol particles for different types of instruments. The unit to unit variability between instruments can be up to 30% for Particle Soot Absorption Photometers (PSAPs) and Aethalometers. Multi Angle Absorption Photometers (MAAPs) showed a variability of less than 5%. Reasons for the high variability were identified to be variations in sample flow and spot size. It was observed that different flow rates influence system performance with respect to response to absorption and instrumental noise. Measurements with non absorbing particles showed that the current corrections of a cross sensitivity to particle scattering are not sufficient. Remaining cross sensitivities were found to be a function of the total particle load on the filter. The large variation between the response to absorbing aerosol particles for different types of instruments indicates that current correction functions for absorption photometers are not adequate
Minería de datos para el descubrimiento de patrones en enfermedades respiratorias en Bogotá, Colombia
Trabajo de InvestigaciónEl presente proyecto se basa en la aplicación de minería de datos mediante el algoritmo de clustering K- means que permita la generación de un modelo descriptivo con el análisis de los datos y con el objetivo de identificar posibles comportamientos en enfermedades respiratorias en la ciudad de Bogotá.
El conjunto de clústeres generados por la herramienta RapidMiner es la
recopilación de datos de un periodo de cinco años de 2012 a 2016, en donde se contemplan el número de casos asociados a 184 diagnósticos de enfermedades respiratorias y la edad de los pacientes corresponde de 0 a 5 años.Trabajo de Investigación1. GENERALIDADES
2. OBJETIVOS
3. JUSTIFICACIÓN
4. DELIMITACIÓN
5. MARCO REFERENCIAL
6. METODOLOGÍA
7. FUENTES DE EXTRACCIÓN Y SUS VARIABLES
8. DISEÑO
9. SELECCIÓN DE ALGORITMOS DE CLUSTERING
10. RECONOCER PATRONES A PARTIR DE LA INFORMACIÓN RECOPILADA
11. CONCLUSIONES
12. TRABAJOS FUTUROS 13. REFERENCIAS BIBLIOGRÁFICAS
14. ANEXOSPregradoIngeniero de Sistema
Significant Association of Estrogen Receptor Binding Site Variation with Bipolar Disorder in Females
Major depression is nearly twice as prevalent in women compared to men. In bipolar disorder, depressive episodes have been reported to be more common amongst female patients. Furthermore, periods of depression often correlate with periods of hormonal fluctuations. A link between hormone signaling and these mood disorders has, therefore, been suggested to exist in many studies. Estrogen, one of the primary female sex hormones, mediates its effect mostly by binding to estrogen receptors (ERs). Nuclear ERs function as transcription factors and regulate gene transcription by binding to specific DNA sequences. A nucleotide change in the binding sequence might alter the binding efficiency, which could affect transcription levels of nearby genes. In order to investigate if variation in ER DNA-binding sequences may be involved in mood disorders, we conducted a genome-wide study of ER DNA-binding in patients diagnosed with major depression or bipolar disorder. Association studies were performed within each gender separately and the results were corrected for multiple testing by the Bonferroni method. In the female bipolar disorder material a significant association result was found for rs6023059 (corrected p-value = 0.023; odds ratio (OR) 0.681, 95% confidence interval (CI) 0.570–0.814), a single nucleotide polymorphism (SNP) placed downstream of the gene coding for transglutaminase 2 (TGM2). Thus, females with a specific genotype at this SNP may be more vulnerable to fluctuating estrogen levels, which may then act as a triggering factor for bipolar disorder
Enhanced sampling in molecular dynamics using metadynamics, replica-exchange, and temperature-acceleration
We review a selection of methods for performing enhanced sampling in molecular dynamics simulations. We consider methods based on collective variable biasing and on tempering, and offer both historical and contemporary perspectives. In collective-variable biasing, we first discuss methods stemming from thermodynamic integration that use mean force biasing, including the adaptive biasing force algorithm and temperature acceleration. We then turn to methods that use bias potentials, including umbrella sampling and metadynamics. We next consider parallel tempering and replica-exchange methods. We conclude with a brief presentation of some combination methods. \ua9 2013 by the author; licensee MDPI, Basel, Switzerland
Phage Therapy and Photodynamic Therapy: Low Environmental Impact Approaches to Inactivate Microorganisms in Fish Farming Plants
Owing to the increasing importance of aquaculture to compensate for the progressive worldwide reduction of natural fish and to the fact that several fish farming plants often suffer from heavy financial losses due to the development of infections caused by microbial pathogens, including multidrug resistant bacteria, more environmentally-friendly strategies to control fish infections are urgently needed to make the aquaculture industry more sustainable. The aim of this review is to briefly present the typical fish farming diseases and their threats and discuss the present state of chemotherapy to inactivate microorganisms in fish farming plants as well as to examine the new environmentally friendly approaches to control fish infection namely phage therapy and photodynamic antimicrobial therapy
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