901 research outputs found
Gene polymorphisms for elucidating the genetic structure of the heavy-metal hyperaccumulating trait in Thlaspi caerulescens and their cross-genera amplification in Brassicaceae.
Genetic polymorphism was investigated in Thlaspi caerulescens J. & C. Presl at 15 gene regions, of which seven have been identified to putatively play a role in heavy-metal tolerance or hyperaccumulation. Single nucleotide and length polymorphisms were assessed at four cleaved amplified polymorphic sequences (CAPS) and 11 simple sequence repeat (microsatellite) loci, respectively. The utility of these loci for genetic studies in T. caerulescens was measured among seven natural populations (135 individuals). Fourteen loci rendered polymorphism, and the number of alleles per locus varied from 2 to 5 and 1 to 27 for CAPS and microsatellites, respectively. Up to 12 alleles per locus were detected in a population. The global observed heterozygosity per population varied between 0.01 and 0.31. Additionally, cross-species/genera amplification of loci was investigated on eight other Brassicaceae (five individuals per population). Overall, 70% of the cross-species/genera amplifications were successful, and among them, more than 40% provided intraspecific polymorphisms within a single population. This indicates that such markers may, as well, allow comparative population genetic or mapping studies between and within several Brassicaceae, particularly for genes involved in traits such as heavy-metal tolerance and/or hyperaccumulation
Gene polymorphisms for elucidating the genetic structure of the heavy-metal hyperaccumulating trait in Thlaspi caerulescens and their cross-genera amplification in Brassicaceae
Genetic polymorphism was investigated in Thlaspi caerulescens J. & C. Presl at 15 gene regions, of which seven have been identified to putatively play a role in heavy-metal tolerance or hyperaccumulation. Single nucleotide and length polymorphisms were assessed at four cleaved amplified polymorphic sequences (CAPS) and 11 simple sequence repeat (microsatellite) loci, respectively. The utility of these loci for genetic studies in T. caerulescens was measured among seven natural populations (135 individuals). Fourteen loci rendered polymorphism, and the number of alleles per locus varied from 2 to 5 and 1 to 27 for CAPS and microsatellites, respectively. Up to 12 alleles per locus were detected in a population. The global observed heterozygosity per population varied between 0.01 and 0.31. Additionally, cross-species/genera amplification of loci was investigated on eight other Brassicaceae (five individuals per population). Overall, 70% of the cross-species/genera amplifications were successful, and among them, more than 40% provided intraspecific polymorphisms within a single population. This indicates that such markers may, as well, allow comparative population genetic or mapping studies between and within several Brassicaceae, particularly for genes involved in traits such as heavy-metal tolerance and/or hyperaccumulatio
The Lorentzian distance formula in noncommutative geometry
For almost twenty years, a search for a Lorentzian version of the well-known
Connes' distance formula has been undertaken. Several authors have contributed
to this search, providing important milestones, and the time has now come to
put those elements together in order to get a valid and functional formula.
This paper presents a historical review of the construction and the proof of a
Lorentzian distance formula suitable for noncommutative geometry.Comment: 16 pages, final form, few references adde
Theory of Mind and Empathy in Preclinical and Clinical Huntington's Disease
We investigated cognitive and affective Theory of Mind (ToM) and empathy in patients with premanifest and manifest Huntington\u27s disease (HD). The relation between ToM performance and executive skills was also examined.
16 preclinical and 23 clinical HD patients, and 39 healthy subjects divided in 2 control groups were given a French adaptation of the Yoni test (Shamay-Tsoory and Aharon-Peretz, 2007) that examines first and second-order cognitive and affective ToM processing in separate conditions with a physical control condition. Participants were also given questionnaires of empathy and cognitive tests which mainly assessed executive functions (inhibition and mental flexibility).
Clinical HD patients made significantly more errors than their controls in the first-and second-order cognitive and affective ToM conditions of the Yoni task, but exhibited no empathy deficits. However, there was no evidence that ToM impairment was related to cognitive deficits in these patients. Preclinical HD patients were unimpaired in ToM tasks and empathy measures compared to their controls.
Our results are consistent with the idea that impaired affective and cognitive mentalising emerges with the clinical manifestation of HD, but is not necessarily part of the preclinical stage. Furthermore, these impairments appear independent of executive dysfunction and empathy
Breaking of the Bancroft rule for multiple emulsions stabilized by a single stimulable polymer
International audienceWe investigated emulsions of water and toluene stabilized by (co)polymers consisting of styrene (S) and 2-(dimethylamino)ethyl methacrylate (DMAEMA) monomer units with different compositions and structures such as a PDMAEMA homopolymer, a P(S-co-DMAEMA) random copolymer and various PS-b-PDMAEMA and PS-b-(S-co-DMAEMA) block copolymers. The model system is used to study the fundamental conditions under which the different kinds of polymer-stabilized emulsions (direct oil in water, inverse water in oil and multiple emulsions) are stabilized or destabilized by pH change (at constant temperature). Polymer properties like chain conformation at the toluene-water interface as probed by SANS and neutron reflectivity at the liquid-liquid interface, the oil-water partitioning of the polymer chains (Bancroft's rule of thumb) as determined by UV spectroscopy and interfacial tensions measured by the rising and spinning drop techniques are determined. Overall, results evidence that the curvature sign, as defined by positive and negative values as the chain segments occupy preferentially the water and toluene sides of the interface respectively, reliably predicts the emulsion kind. In contrast, the Bancroft rule failed at foreseeing the emulsion type. In the region of near zero curvature the crossover from direct to inverse emulsions occurs through the formation of either unstable coexisting direct and inverse emulsions (i) or multiple emulsions (ii). The high compact adsorption of the chains at the interface as shown by low interfacial tension values does not allow to discriminate between both cases. However, the toluene-water partitioning of the polymeric emulsifier is still a key factor driving the formation of (i) or (ii) emulsions. Interestingly, the stabilization of the multiple emulsions can be tuned to a large extent as the toluene-water polymer partitioning can be adjusted using quite a large number of physico-chemical parameters linked to polymer architecture like diblock length ratio or polymer total molar mass, for example. Moreover, we show that monitoring the oil-water partitioning aspect of the emulsion system can also be used to lower the interfacial tension at low pH to values slightly higher than 0.01 mN m-1, irrespective of the curvature sign
Polyploidy in the Olive Complex (Olea europaea): Evidence from Flow Cytometry and Nuclear Microsatellite Analyses
Background Phylogenetic and phylogeographic investigations have been previously performed to study the evolution of the olive tree complex (Olea europaea). A particularly high genomic diversity has been found in north-west Africa. However, to date no exhaustive study has been addressed to infer putative polyploidization events and their evolutionary significance in the diversification of the olive tree and its relatives. Methods Representatives of the six olive subspecies were investigated using (a) flow cytometry to estimate genome content, and (b) six highly variable nuclear microsatellites to assess the presence of multiple alleles at co-dominant loci. In addition, nine individuals from a controlled cross between two individuals of O. europaea subsp. maroccana were characterized with microsatellites to check for chromosome inheritance. Key Results Based on flow cytometry and genetic analyses, strong evidence for polyploidy was obtained in subspp. cerasiformis (tetraploid) and maroccana (hexaploid), whereas the other subspecies appeared to be diploids. Agreement between flow cytometry and genetic analyses gives an alternative approach to chromosome counting to determine ploidy level of trees. Lastly, abnormalities in chromosomes inheritance leading to aneuploid formation were revealed using microsatellite analyses in the offspring from the controlled cross in subsp. maroccana. Conclusions This study constitutes the first report for multiple polyploidy in olive tree relatives. Formation of tetraploids and hexaploids may have played a major role in the diversification of the olive complex in north-west Africa. The fact that polyploidy is found in narrow endemic subspecies from Madeira (subsp. cerasiformis) and the Agadir Mountains (subsp. maroccana) suggests that polyploidization has been favoured to overcome inbreeding depression. Lastly, based on previous phylogenetic analyses, we hypothesize that subsp. cerasiformis resulted from hybridization between ancestors of subspp. guanchica and europae
Reconstruction of Hydraulic Data by Machine Learning
Numerical simulation models associated with hydraulic engineering take a wide
array of data into account to produce predictions: rainfall contribution to the
drainage basin (characterized by soil nature, infiltration capacity and
moisture), current water height in the river, topography, nature and geometry
of the river bed, etc. This data is tainted with uncertainties related to an
imperfect knowledge of the field, measurement errors on the physical parameters
calibrating the equations of physics, an approximation of the latter, etc.
These uncertainties can lead the model to overestimate or underestimate the
flow and height of the river. Moreover, complex assimilation models often
require numerous evaluations of physical solvers to evaluate these
uncertainties, limiting their use for some real-time operational applications.
In this study, we explore the possibility of building a predictor for river
height at an observation point based on drainage basin time series data. An
array of data-driven techniques is assessed for this task, including
statistical models, machine learning techniques and deep neural network
approaches. These are assessed on several metrics, offering an overview of the
possibilities related to hydraulic time-series. An important finding is that
for the same hydraulic quantity, the best predictors vary depending on whether
the data is produced using a physical model or real observations.Comment: Submitted to SimHydro 201
Environmental dependency phenomena in schizophrenia: a pilot study
INTRODUCTION: Environmental dependency phenomena refer to the enslavement of patients\u27 performances under the characteristics of the tasks and were first described in case of prefrontal lobe damage. Two forms of environmental dependency, executive and social, may be dissociated, which involve respectively dorsolateral and orbital prefrontal cortex (PFC) dysfunction. Schizophrenia is widely considered to be caused by PFC dysfunction, but no study to date has addressed environmental dependency in this pathology.
METHODS: We compared patients (N = 17) and healthy controls (N = 28) on a task dedicated to the study of environmental dependency.
RESULTS: Our results demonstrate the presence of environmental dependency in schizophrenia. Each form of environmental dependency can be highlighted independently, as previously demonstrated by studies with prefrontal patients.
CONCLUSIONS: These findings suggest specific prefrontal dysfunction for each subgroup of patients and demonstrate a dissociation between socio-cognitive and neurocognitive performance in schizophrenia. Additionally, we found relationships between symptomatology and environmental dependency. This pilot study supports the relevance of studying environmental dependency to highlight specific patterns of prefrontal disorders in schizophrenia, which may contribute to a better understanding of PFC dysfunction in schizophrenia
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