835 research outputs found
Discriminating faunal assemblages and their palaeoecology based on museum collections : the Carboniferous Hurlet and Index limestones of western Scotland
Historical collections of Scottish Carboniferous macrofossils stored at the British Geological Survey (BGS), Edinburgh include the sole remaining sources of palaeontological data from numerous localities. Exploratory numerical analyses of such collections from the Hurlet and Index limestones of Ayrshire compare favourably with published qualitative assessments of faunal assemblages and palaeoenvironments; demonstrating that old collections can still be used in modern palaeoecological investigations. Macrofaunas from these formations comprise mainly brachiopods and molluscs and were collected from 67 localities that yielded 20 and 94 samples from the Hurlet and Index limestones respectively. Limitations of the presence/absence data were partly overcome by consolidation and restriction of aspects of the data set. Seriation indicates the lithological and environmental gradients of taxa. Cluster analysis reveals groups of samples linked to lithofacies. Principal Components Analysis (PCA) of diversity data derived from the data set in terms of numbers of genera in higher taxa highlights differences in gross taxonomic composition in terms of trophic structure, lithology and environment.
Supplementary material: lists of localities taxa and sample lithologies used in this study are available at http://www.geolsoc.org.uk/SUP1840
Minimal model for aeolian sand dunes
We present a minimal model for the formation and migration of aeolian sand
dunes. It combines a perturbative description of the turbulent wind velocity
field above the dune with a continuum saltation model that allows for
saturation transients in the sand flux. The latter are shown to provide the
characteristic length scale. The model can explain the origin of important
features of dunes, such as the formation of a slip face, the broken scale
invariance, and the existence of a minimum dune size. It also predicts the
longitudinal shape and aspect ratio of dunes and heaps, their migration
velocity and shape relaxation dynamics. Although the minimal model employs
non-local expressions for the wind shear stress as well as for the sand flux,
it is simple enough to serve as a very efficient tool for analytical and
numerical investigations and to open up the way to simulations of large scale
desert topographies.Comment: 19 pages, 22 figure
Ethephon use and application timing of abscisic acid for improving color of 'Rubi' table grape
Literature review – assessing groundwater recharge estimates under conventional tillage and conservation agriculture
The purpose of this review is to identify studies from across the world that evaluated the impact of
conservation agriculture (CA) on potential groundwater recharge in comparison to conventional tillage
(CT), taking into consideration the techniques that have been used in measuring the soil or
groundwater fluxes. In this review, we quantify case studies in which direct and indirect methods have
been used to calculate a direct or proxy value of groundwater recharge under the different agricultural
treatments of CA and CT.
This review revealed that CA systems have the potential to improve infiltration or deep drainage and
therefore potential recharge to the groundwater as evidenced by 54% of the case studies, including
all studies (n=5) in the SADC region, however significant proportion of studies, mainly from the
Americas and Europe, also reported either reduced potential recharge or no significant difference
under different treatments. A majority of these studies used infiltration rates as a proxy. This review
demonstrates that consideration on the methods used in estimating infiltration rates is important
when evaluating the impact of agricultural systems on groundwater recharge in different climate
zones. Issues such as the infiltration measurement technique used, timing of the measurements
within the season, rainfall intensity, and soil type, are some of the parameters that must be carefully
stated in studies to allow the infiltration rates within and across treatments to be comparable.
The review revealed a gap in the literature for studies that used direct methods of recharge estimation
to evaluate the impact of CA vs CT treatments. Unsaturated zone techniques provide only estimates
of potential recharge based on drainage rates below the root zone and in some cases, drainage is
diverted laterally and does not reach the water table. Use of direct methods that allow collection of
data from the saturated zone such as groundwater level fluctuations in monitoring boreholes and
environmental tracers such as Cl and stable isotopes of water, would be greatly beneficial to further
our understanding of groundwater recharge processes beneath CA and CT systems. However, direct
observations are more challenging to acquire and do have limitations
Mesoscale subduction at the Almeria-Oran front. Part 2: biophysical interactions.
This paper presents a detailed diagnostic analysis of hydrographic and current meter data from three, rapidly repeated, fine-scale surveys of the Almeria–Oran front. Instability of the frontal boundary, between surface waters of Atlantic and Mediterranean origin, is shown to provide a mechanism for significant heat transfer from the surface layers to the deep ocean in winter. The data were collected during the second observational phase of the EU funded OMEGA project on RRS Discovery cruise 224 during December 1996. High resolution hydrographic measurements using the towed undulating CTD vehicle, SeaSoar, traced the subduction of Mediterranean Surface Water across the Almeria–Oran front. This subduction is shown to result from a significant baroclinic component to the instability of the frontal jet. The Q-vector formulation of the omega equation is combined with a scale analysis to quantitatively diagnose vertical transport resulting from mesoscale ageostrophic circulation. The analyses are presented and discussed in the presence of satellite and airborne remotely sensed data; which provide the basis for a thorough and novel approach to the determination of observational error
Association Between Schizophrenia-Related Polygenic Liability and the Occurrence and Level of Mood-Incongruent Psychotic Symptoms in Bipolar Disorder
Importance
Bipolar disorder (BD) overlaps schizophrenia in its clinical presentation and genetic liability. Alternative approaches to patient stratification beyond current diagnostic categories are needed to understand the underlying disease processes/mechanisms.
Objectives
To investigate the relationship between common-variant liability for schizophrenia, indexed by polygenic risk scores (PRS) and psychotic presentations of BD, using clinical descriptions which consider both occurrence and level of mood-incongruent psychotic features.
Design
Case-control design: using multinomial logistic regression, to estimate differential associations of PRS across categories of cases and controls.
Settings & Participants
4399 BD cases, 2966 (67%) female, mean age-at-interview 46 [sd 12] years, from the BD Research Network (BDRN) were included in the final analyses. For comparison genotypic data for 4976 schizophrenia cases and 9012 controls from the Type-1 diabetes genetics consortium and Generation Scotland were included.
Exposure
Standardised PRS, calculated using alleles with an association p-value threshold < 0.05 in the second Psychiatric Genomics Consortium genome-wide association study of schizophrenia, adjusted for the first 10 population principal components and genotyping-platform.
Main outcome measure
Multinomial logit models estimated PRS associations with BD stratified by (1) Research Diagnostic Criteria (RDC) BD subtypes (2) Lifetime occurrence of psychosis.(3) Lifetime mood-incongruent psychotic features and (4) ordinal logistic regression examined PRS associations across levels of mood-incongruence. Ratings were derived from the Schedule for Clinical Assessment in Neuropsychiatry interview (SCAN) and the Bipolar Affective Disorder Dimension Scale (BADDS).
Results
Across clinical phenotypes, there was an exposure-response gradient with the strongest PRS association for schizophrenia (RR=1.94, (95% C.I. 1.86, 2.01)), then schizoaffective BD (RR=1.37, (95% C.I. 1.22, 1.54)), BD I (RR= 1.30, (95% C.I. 1.24, 1.36)) and BD II (RR=1.04, (95% C.I. 0.97, 1.11)). Within BD cases, there was an effect gradient, indexed by the nature of psychosis, with prominent mood-incongruent psychotic features having the strongest association (RR=1.46, (95% C.I. 1.36, 1.57)), followed by mood-congruent psychosis (RR= 1.24, (95% C.I. 1.17, 1.33)) and lastly, BD cases with no history of psychosis (RR=1.09, (95% C.I. 1.04, 1.15)).
Conclusion
We show for the first time a polygenic-risk gradient, across schizophrenia and bipolar disorder, indexed by the occurrence and level of mood-incongruent psychotic symptoms
Developing a relational approach to energy demand: A methodological and conceptual guide
In a recent review of research on the role of social relations in shaping energy demand, authors documented increasing interest in relational approaches to energy [1]. Relational approaches to energy conceive of human behaviour as produced and reproduced by social relations and interactions, placing relationships at the centre of inquiry, as well as understanding these relationships in the context of infrastructure and the built environment. In this paper, we build on a relational approach in new economic sociology, and on our research project about the social relations of energy retrofit, to offer a methodological and conceptual guide to those working on energy demand topics. We detail the ontological and epistemological starting points of our relational approach, and articulate how research can be designed to capture the role of social relations in shaping decision-making on energy, as well as to offer innovative insights for policy-makers and practitioners. We use our experience in a research project on energy retrofit as a case study, reflecting on the practical aspects of this research approach to provide suggestions for research design for those interested in doing similar work. This includes defining key concepts and the way they interact in a conceptual framework for a relational approach to energy. We also offer some conceptually driven research questions as a starting point for energy research projects. We finish by discussing the potential for further application of these ideas in research, policy and practice
Genetic and Phenotypic Features of Schizophrenia in the UK Biobank
IMPORTANCE Large-scale biobanks provide important opportunities for mental health
research, but selection biases raise questions regarding the comparability of individuals
with those in clinical research settings.
OBJECTIVE To compare the genetic liability to psychiatric disorders in individuals with
schizophrenia in the UK Biobank with individuals in the Psychiatric Genomics Consortium
(PGC) and to compare genetic liability and phenotypic features with participants recruited
from clinical settings.
DESIGN, SETTING, AND PARTICIPANTS This cross-sectional study included participants from
the population-based UK Biobank and schizophrenia samples recruited from clinical settings
(CLOZUK, CardiffCOGS, Cardiff F-Series, and Cardiff Affected Sib-Pairs). Data were collected
between January 1993 and July 2021. Data analysis was conducted between July 2021
and June 2023.
MAIN OUTCOMES AND MEASURES A genome-wide association study of UK Biobank
schizophrenia case-control status was conducted, and the results were compared with
those from the PGC via genetic correlations. To test for differences with the clinical samples,
polygenic risk scores (PRS) were calculated for schizophrenia, bipolar disorder, depression,
and intelligence using PRS-CS. PRS and phenotypic comparisons were conducted using
pairwise logistic regressions. The proportions of individuals with copy number variants
associated with schizophrenia were compared using Firth logistic regression.
RESULTS The sample of 517 375 participants included 1438 UK Biobank participants with
schizophrenia (550 [38.2%] female; mean [SD] age, 54.7 [8.3] years), 499 475 UK Biobank
controls (271 884 [54.4%] female; mean [SD] age, 56.5 [8.1] years), and 4 schizophrenia
research samples (4758 [28.9%] female; mean [SD] age, 38.2 [21.0] years). Liability to
schizophrenia in UK Biobank was highly correlated with the latest genome-wide association
study from the PGC (genetic correlation, 0.98; SE, 0.18) and showed the expected patterns
of correlations with other psychiatric disorders. The schizophrenia PRS explained 6.8% of the
variance in liability for schizophrenia case status in UK Biobank. UK Biobank participants with
schizophrenia had significantly lower schizophrenia PRS than 3 of the clinically ascertained
samples and significantly lower rates of schizophrenia-associated copy number variants than
the CLOZUK sample. UK Biobank participants with schizophrenia had higher educational
attainment and employment rates than the clinically ascertained schizophrenia samples,
lower rates of smoking, and a later age of onset of psychosis.
CONCLUSIONS AND RELEVANCE Individuals with schizophrenia in the UK Biobank, and likely
other volunteer-based biobanks, represent those less severely affected. Their inclusion in
wider studies should enhance the representation of the full spectrum of illness severity
Determination of the Deep Inelastic Contribution to the Generalised Gerasimov-Drell-Hearn Integral for the Proton and Neutron
The virtual photon absorption cross section differences [sigma_1/2-sigma_3/2]
for the proton and neutron have been determined from measurements of polarised
cross section asymmetries in deep inelastic scattering of 27.5 GeV
longitudinally polarised positrons from polarised 1H and 3He internal gas
targets. The data were collected in the region above the nucleon resonances in
the kinematic range nu < 23.5 GeV and 0.8 GeV**2 < Q**2 < 12 GeV**2. For the
proton the contribution to the generalised Gerasimov-Drell-Hearn integral was
found to be substantial and must be included for an accurate determination of
the full integral. Furthermore the data are consistent with a QCD
next-to-leading order fit based on previous deep inelastic scattering data.
Therefore higher twist effects do not appear significant.Comment: 6 pages, 3 figures, 1 table, revte
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