172 research outputs found
Alignments of Voids in the Cosmic Web
We investigate the shapes and mutual alignment of voids in the large scale
matter distribution of a LCDM cosmology simulation. The voids are identified
using the novel WVF void finder technique. The identified voids are quite
nonspherical and slightly prolate, with axis ratios in the order of c:b:a
approx. 0.5:0.7:1. Their orientations are strongly correlated with significant
alignments spanning scales >30 Mpc/h.
We also find an intimate link between the cosmic tidal field and the void
orientations. Over a very wide range of scales we find a coherent and strong
alignment of the voids with the tidal field computed from the smoothed density
distribution. This orientation-tide alignment remains significant on scales
exceeding twice the typical void size, which shows that the long range external
field is responsible for the alignment of the voids. This confirms the view
that the large scale tidal force field is the main agent for the large scale
spatial organization of the Cosmic Web.Comment: 10 pages, 4 figures, submitted to MNRAS, for high resolution version,
see http://www.astro.rug.nl/~weygaert/tim1publication/voidshape.pd
Risk of criminal victimisation in outpatients with common mental health disorders
Crime victimisation is a serious problem in psychiatric patients. However, research has focused on patients with severe mental illness and few studies exist that address victimisation in other outpatient groups, such as patients with depression. Due to large differences in methodology of the studies that address crime victimisation, a comparison of prevalence between psychiatric diagnostic groups is hard to make. Objectives of this study were to determine and compare one-year prevalence of violent and non-violent criminal victimisation among outpatients from different diagnostic psychiatric groups and to examine prevalence differences with the general population.Criminal victimisation prevalence was measured in 300 outpatients living in Amsterdam, The Netherlands. Face-to-face interviews were conducted with outpatients with depressive disorder (n = 102), substance use disorder (SUD, n = 106) and severe mental illness (SMI, n = 92) using a National Crime Victimisation Survey, and compared with a matched general population sample (n = 10865).Of all outpatients, 61% reported experiencing some kind of victimisation over the past year; 33% reported violent victimisation (3.5 times more than the general population) and 36% reported property crimes (1.2 times more than the general population). Outpatients with depression (67%) and SUD (76%) were victimised more often than SMI outpatients (39%). Younger age and hostile behaviour were associated with violent victimisation, while being male and living alone were associated with non-violent victimisation. Moreover, SUD was associated with both violent and non-violent victimisation.Outpatients with depression, SUD, and SMI are at increased risk of victimisation compared to the general population. Furthermore, our results indicate that victimisation of violent and non-violent crimes is more common in outpatients with depression and SUD than in outpatients with SMI living independently in the community
Spin alignment of dark matter haloes in filaments and walls
The MMF technique is used to segment the cosmic web as seen in a cosmological
N-body simulation into wall-like and filament-like structures. We find that the
spins and shapes of dark matter haloes are significantly correlated with each
other and with the orientation of their host structures. The shape orientation
is such that the halo minor axes tend to lie perpendicular to the host
structure, be it a wall or filament. The orientation of the halo spin vector is
mass dependent. Low mass haloes in walls and filaments have a tendency to have
their spins oriented within the parent structure, while higher mass haloes in
filaments have spins that tend to lie perpendicular to the parent structure.Comment: 4 pages, 2 figure
Electrophysiological method for recording intracellular voltage responses of Drosophila photoreceptors and interneurons to light stimuli in vivo
Voltage responses of insect photoreceptors and visual interneurons can be accurately recorded
with conventional sharp microelectrodes. The method described here enables the investigator
to measure long-lasting (from minutes to hours) high-quality intracellular responses from single
Drosophila R1-R6 photoreceptors and Large Monopolar Cells (LMCs) to light stimuli. Because
the recording system has low noise, it can be used to study variability among individual cells in
the fly eye, and how their outputs reflect the physical properties of the visual environment. We
outline all key steps in performing this technique. The basic steps in constructing an
appropriate electrophysiology set-up for recording, such as design and selection of the
experimental equipment are described. We also explain how to prepare for recording by
making appropriate (sharp) recording and (blunt) reference electrodes. Details are given on
how to fix an intact fly in a bespoke fly-holder, prepare a small window in its eye and insert a
recording electrode through this hole with minimal damage. We explain how to localize the center of a cell’s receptive field, dark - or light-adapt the studied cell, and to record its voltage
responses to dynamic light stimuli. Finally, we describe the criteria for stable normal recordings,
show characteristic high-quality voltage responses of individual cells to different light stimuli,
and briefly define how to quantify their signaling performance. Many aspects of the method are
technically challenging and require practice and patience to master. But once learned and
optimized for the investigator’s experimental objectives, it grants outstanding in vivo
neurophysiological data
Spatiotemporal endothelial cell-pericyte association in tumors as shown by high resolution 4D intravital imaging
Endothelial cells and pericytes are integral cellular components of the vasculature with distinct interactive functionalities. To study dynamic interactions between these two cells we created two transgenic animal lines. A truncated eNOS (endothelial nitric oxide synthase) construct was used as a GFP tag for endothelial cell evaluation and an inducible Cre-lox recombination, under control of the Pdgfrb (platelet derived growth factor receptor beta) promoter, was created for pericyte assessment. Also, eNOStag-GFP animals were crossed with the already established Cspg4-DsRed mice expressing DsRed fluorescent protein in pericytes. For intravital imaging we used tumors implanted in the dorsal skinfold of these transgenic animals. This setup allowed us to study time and space dependent complexities, such as distribution, morphology, motility, and association between both vascular cell types in all angiogenetic stages, without the need for additional labeling. Moreover, as fluorescence was still clearly detectable after fixation, it is possible to perform comparative histology following intravital evaluation. These transgenic mouse lines form an excellent model to capture collective and individual cellular and subcellular endothelial cell-pericyte dynamics and will help answer key questions on the cellular and molecular relationship between these two cells
Формування світогляду О. Кониського
Crime victimisation is a serious problem in psychiatric patients. However, research has focused on patients with severe mental illness and few studies exist that address victimisation in other outpatient groups, such as patients with depression. Due to large differences in methodology of the studies that address crime victimisation, a comparison of prevalence between psychiatric diagnostic groups is hard to make. Objectives of this study were to determine and compare one-year prevalence of violent and non-violent criminal victimisation among outpatients from different diagnostic psychiatric groups and to examine prevalence differences with the general population.Criminal victimisation prevalence was measured in 300 outpatients living in Amsterdam, The Netherlands. Face-to-face interviews were conducted with outpatients with depressive disorder (n = 102), substance use disorder (SUD, n = 106) and severe mental illness (SMI, n = 92) using a National Crime Victimisation Survey, and compared with a matched general population sample (n = 10865).Of all outpatients, 61% reported experiencing some kind of victimisation over the past year; 33% reported violent victimisation (3.5 times more than the general population) and 36% reported property crimes (1.2 times more than the general population). Outpatients with depression (67%) and SUD (76%) were victimised more often than SMI outpatients (39%). Younger age and hostile behaviour were associated with violent victimisation, while being male and living alone were associated with non-violent victimisation. Moreover, SUD was associated with both violent and non-violent victimisation.Outpatients with depression, SUD, and SMI are at increased risk of victimisation compared to the general population. Furthermore, our results indicate that victimisation of violent and non-violent crimes is more common in outpatients with depression and SUD than in outpatients with SMI living independently in the community
Predicting infant–father attachment: the role of pre- and postnatal triadic family alliance and paternal testosterone levels
This longitudinal study examined whether prenatal family alliance and prenatal paternal testosterone levels predicted infant–mother and infant–father attachment security and whether this association was mediated by postnatal family alliance and postnatal paternal testosterone levels. In 105 couples expecting their first child, family alliance was assessed in the third trimester of pregnancy with the prenatal version of the Lausanne Trilogue Play (LTP). Family alliance was measured again 6 months postnatally, using the LTP. Fathers provided testosterone samples prenatally and at 6 months postnatally. Infant–parent attachment was assessed with the Attachment Q-Sort (AQS) at 24 months. Results indicated an increase in paternal testosterone levels from the pre- to the postnatal period. A more positive prenatal family alliance predicted higher infant–father attachment security at 24 months, but not infant–mother attachment security. The association between prenatal family alliance and attachment security was not mediated by postnatal family alliance or postnatal paternal testosterone levels. This study highlights the significance of prenatal family relation
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Ecological consequences of the expansion of N₂‑fixing plants in cold biomes
Research in warm-climate biomes has shown that invasion by symbiotic dinitrogen (N₂)-fixing plants can transform ecosystems in ways analogous to the transformations observed as a consequence of anthropogenic, atmospheric nitrogen (N) deposition: declines in biodiversity, soil acidification, and alterations to carbon and nutrient cycling, including increased N losses through nitrate leaching and emissions of the powerful greenhouse gas nitrous oxide (N₂O). Here, we used literature review and case study approaches to assess the evidence for similar transformations in cold-climate ecosystems of the boreal, subarctic and upper montane-temperate life zones. Our assessment focuses on the plant genera Lupinus and Alnus, which have become invasive largely as a consequence of deliberate introductions and/or reduced land management. These cold biomes are commonly located in remote areas with low anthropogenic N inputs, and the environmental impacts of N₂-fixer invasion appear to be as severe as those from anthropogenic N deposition in highly N polluted areas. Hence, inputs of N from N₂ fixation can affect ecosystems as dramatically or even more strongly than N inputs from atmospheric deposition, and biomes in cold climates represent no exception with regard to the risk of being invaded by N₂-fixing species. In particular, the cold biomes studied here show both a strong potential to be transformed by N₂-fixing plants and a rapid subsequent saturation in the ecosystem’s capacity to retain N. Therefore, analogous to increases in N deposition, N₂-fixing plant invasions must be deemed significant threats to biodiversity and to environmental quality.Keywords: Carbon, Lupinus, Biodiversity, Invasive, Nitrogen, Alnu
Victimization of patients with severe psychiatric disorders: prevalence, risk factors, protective factors and consequences for mental health. A longitudinal study
<p>Abstract</p> <p>Background</p> <p>Victimization among people with a Severe Mental Illness is a common phenomenon. The objectives of this study proposal are: to delineate the extent and kind of victimization in a representative sample of chronic psychiatric patients; to contribute to the development and validation of a set of instruments registering victimization of psychiatric patients; to determine risk factors and protective factors; and to gain insight into the possible consequences of victimization.</p> <p>Methods/Design</p> <p>An extensive data set of 323 patients with Sever Mental Illness (assessed 4 years ago) is used. In 2010 a second measurement will be performed, enabling longitudinal research on the predictors and consequences of victimization.</p> <p>Discussion</p> <p>The consequences of (re)victimization have barely been subjected to analysis, partially due to the lack of a comprehensive, conceptual model for victimization. This research project will contribute significantly to the scientific development of the conceptual model of victimization in chronic psychiatric patients.</p
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