6,082 research outputs found
Prompt photon, Drell-Yan and Bethe-Heitler processes in hard photoproduction
We present prospects and requirements for the study at HERA of hard photon
processes which generate high photons in the final state, and processes
which generate Drell-Yan lepton pairs.Comment: 6 pages, 3 embedded figures. To appear in the proceedings of the
workshop "Future physics at HERA
QCD Physics with ZEUS and H1 at HERA
A review is presented of recent results in QCD from the H1 and ZEUS
experiments at HERA, emphasizing the use of higher order calculations to
describe the data.Comment: 12 pages, 15 figures, invited review paper for Mod. Phys. Lett
Discrimination of computer-graphic stimuli by mice: a method for the behavioral characterization of transgenic and gene-knockout models.
An automated method is described for the behavioral testing of mice in an apparatus that allows computer-graphic stimulus material to be presented. Mice responded to these stimuli by making a nose-poke toward a computer monitor that was equipped with a touchscreen attachment for detecting responses. It was found that C57BL/6 mice were able to solve single-pair visual discriminations as well as 3-pair concurrent visual discriminations. The finding that mice are capable of complex visual discriminations introduces the possibility of testing mice on nonspatial tasks that are similar to those used with rats, monkeys, and humans. Furthermore, the method seems particularly well suited to the comprehensive behavioral assessment of transgenic and gene-knockout models
PERFORMANCE OF TRANSGENIC TgTau-P301L MICE IN A 5-CHOICE SERIAL REACTION TIME TASK (5-CSRTT) AS A MODEL OF ALZHEIMER’S DISEASE
Alzheimer’s disease is increasing to epidemic levels with an estimated 36 million people affected worldwide (Wimo 2010). The
aetiology of the disease is not known, which is hindering the progression of the treatment. This study is a longitudinal investigation
into the performance of TgTauP301L mice as an animal model of Alzheimer’s disease on the computer automated touchscreen 5-
choice serial reaction time task (5-CSRTT). TgTauP301L mice have a single tau mutation in the P301L gene and develop the tau
pathology that represents the observed tauopathy in patients with Alzheimer’s disease.
The aim of the investigation is to observe if tau pathology in the TgTauP301L mice causes a cognitive impairment in attention
and executive function and at what stage this can be identified by the 5-CSRTT task. This will establish if the animals can be used as
a therapeutic model for pre-clinical drug trials and help to identify an early indicator and intervention point in patients with
Alzheimer’s disease. The animals have previously been studied at 5-months and no differences between performances of the
TgTauP301L mice and wild type mice were found (unpublished data). This study measured the performance of the animals at 7-
months which is when the tauopathy begins to develop in TgTauP301L mice (Murakami 2005). The results of this study showed that
there was no deficit in the performance of the TgTauP301L compared to the wild type mice and there had been no change in the
animals’ performance compared to at 5-months. The animals will be retested at 12-months once the pathology has extensively spread
to see if the tauopathy causes a deficit in performance
Adult hippocampal neurogenesis and its role in cognition.
UNLABELLED: Adult hippocampal neurogenesis (AHN) has intrigued neuroscientists for decades. Several lines of evidence show that adult-born neurons in the hippocampus are functionally integrated and contribute to cognitive function, in particular learning and memory processes. Biological properties of immature hippocampal neurons indicate that these cells are more easily excitable compared with mature neurons, and demonstrate enhanced structural plasticity. The structure in which adult-born hippocampal neurons are situated-the dentate gyrus-is thought to contribute to hippocampus function by disambiguating similar input patterns, a process referred to as pattern separation. Several ideas about AHN function have been put forward; currently there is good evidence in favor of a role for AHN in pattern separation. This function of AHN may be understood within a 'representational-hierarchical' view of brain organization. WIREs Cogn Sci 2014, 5:573-587. doi: 10.1002/wcs.1304 For further resources related to this article, please visit the WIREs website. CONFLICT OF INTEREST: The authors have declared no conflicts of interest for this article.The discovery of neurogenesis in the brain of adult mammals1-3
, including humans4
, received
considerable attention as it challenged the prevailing dogma that the brain is ‘post-mitotic’ and as
such is endowed with limited regenerative capacity. In the mammalian brain, adult neurogenesis is
restricted to two regions: 1. the DG, at the border of the granule cell layer and hilus (the subgranular
zone) where adult neurogenesis gives rise to the primary granule cells (GCs), and 2. the
subventricular zone of the lateral ventricles; cells born here subsequently migrate to the olfactory
bulb5-7
. Given the well-established role of the hippocampus in learning and memory8
, it was soon
suggested that AHN may contribute to these functions in some way. This idea was supported by the
finding that memory demand correlated with AHN in birds9
and that in rats AHN could be stimulated
by learning a spatial task10. In this manuscript, we will review some of the biological properties of
adult-born hippocampal neurons and provide an overview of the structure in which adult-born
hippocampal neurons are situated, the dentate gyrus. This is followed by an overview of studies that
have addressed a putative role of AHN in learning and memory function and a discussion of the ideas
on how adult-born hippocampal neurons may contribute to hippocampus function.This is the author accepted manuscript. The final version is available from Wiley at http://onlinelibrary.wiley.com/doi/10.1002/wcs.1304/abstract
The role of the dorsal hippocampus in two versions of the touchscreen automated paired associates learning (PAL) task for mice.
RATIONALE: The CANTAB object-location paired-associate learning (PAL) test can detect cognitive deficits in schizophrenia and Alzheimer's disease. A rodent version of touch screen PAL (dPAL) has been developed, but the underlying neural mechanisms are not fully understood. Although there is evidence that inactivation of the hippocampus following training leads to impairments in rats, this has not been tested in mice. Furthermore, it is not known whether acquisition, as opposed to performance, of the rodent version depends on the hippocampus. This is critical as many mouse models may have hippocampal dysfunction prior to the onset of task training. OBJECTIVES: The objectives of this study are to examine the effects of dorsal hippocampal (dHp) dysfunction on both performance and acquisition of mouse dPAL and to determine if hippocampal task sensitivity could be increased using a newly developed context-disambiguated PAL (cdPAL) paradigm. METHODS: In experiment 1, C57Bl/6 mice received post-acquisition dHp infusions of the GABA agonist muscimol. In experiment 2, C57Bl/6 mice received excitotoxic dHp lesions prior to dPAL/cdPAL acquisition. RESULTS: Post-acquisition muscimol dose-dependently impaired dPAL and cdPAL performance. Pre-acquisition dHp lesions had only mild effects on both PAL tasks. Behavioural challenges including addition of objects and degradation of the visual stimuli with noise did not reveal any further impairments. CONCLUSIONS: dPAL and cdPAL performance is hippocampus-dependent in the mouse, but both tasks can be learned in the absence of a functional dHp.CHK received funding from the Korean Health
Technology R&D Project, Ministry of Health & Welfare, Republic of
Korea (HI11C1183). CJH, LMS and TJB were funded by Medical Research
Council/Wellcome Trust grant 089703/Z/09/Z. BAK was funded
by a Gates-Cambridge Fellowship. LMS and TJB also received funding
from the Innovative Medicine Initiative Joint Undertaking under grant
agreement no 115008 of which resources are composed of EFPIA inkind
contribution and financial contribution from the European Union’s
Seventh Framework Programme (FP7/2007-2013).This is the final published version. It first appeared from Springer at http://dx.doi.org/10.1007/s00213-015-3949-
Primakoff effect in eta-photoproduction off protons
We analyse data on forward eta-meson photoproduction off a proton target and
extract the eta to gamma gamma decay width utilizing the Primakoff effect. The
hadronic amplitude that enters into our analysis is strongly constrained
because it is fixed from a global fit to available gamma p to p eta data for
differential cross sections and polarizations. We compare our results with
present information on the two-photon eta-decay from the literature. We provide
predictions for future PrimEx experiments at Jefferson Laboratory in order to
motivate further studies.Comment: 5 pages, 6 figures, gamma-gamma*-eta form factor included, version to
appear in Eur. Phys. J. A
Central exclusive production of longlived gluinos at the LHC
We examine the possibility of producing gluino pairs at the LHC via the
exclusive reaction pp -> p+gluino+gluino+p in the case where the gluinos are
long lived. Such long lived gluinos are possible if the scalar super-partners
have large enough masses. We show that it may be possible to observe the
gluinos via their conversion to R-hadron jets and measure their mass to better
than 1% accuracy for masses below 350 GeV with 300/fb of data.Comment: 13 pages, 9 figures. Minor corrections to version
Double dissociation between the effects of peri-postrhinal cortex and hippocampal lesions on tests of object recognition and spatial memory: heterogeneity of function within the temporal lobe.
It is widely believed that declarative memory is mediated by a medial temporal lobe memory system consisting of several distinct structures, including the hippocampus and perirhinal cortex. The strong version of this view assumes a high degree of functional homogeneity and serial organization within the medial temporal lobe, such that double dissociations between individual structures should not be possible. In the present study, we tested for a functional double dissociation between the hippocampus and peri-postrhinal cortex in a single experiment. Rats with bilateral excitotoxic lesions of either the hippocampus or peri-postrhinal cortex were assessed in tests of spatial memory (radial maze) and object recognition memory. For the latter, the spontaneous object recognition task was conducted in a modified apparatus designed to minimize the potentially confounding influence of spatial and contextual factors. A clear functional double dissociation was observed: rats with hippocampal lesions were impaired relative to controls and those with peripostrhinal cortex lesions on the spatial memory task, whereas rats with peri-postrhinal lesions were impaired relative to the hippocampal and control groups in object recognition. These results provide strong evidence in favor of heterogeneity and independence of function within the temporal lobe
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Diabetes and disordered eating behaviours in a community-based sample of australian adolescents
Background:People with diabetes have been shown to be at risk for disordered eating compared to their non-diabetic peers. However, the majority of studies have been conducted in relatively small samples drawn from clinical diabetes settings or registries. Community-based samples are required to better understand disordered eating behaviours in this population. In a large community-based population sample of Australian adolescents, this study aimed to (1) investigate disordered eating behaviours in adolescents reporting a diagnosis of diabetes compared to their non-diabetic peers and (2) test associations between disordered eating behaviours and insulin restriction.Methods:Secondary school students (n = 4854; mean (SD) age 14.4 (1.6) years; 47% boys) completed an online survey, including self-reported presence of diabetes, demographics, weight status, substance use, insulin restriction and disordered eating behaviours. Clinically meaningful cut-offs for disordered eating behaviours were generated for analysis.Results:Disordered eating behaviours, specifically self-induced vomiting (diabetes 19.2%, no diabetes 3.3%; p p p p Conclusion:There was a high rate of disordered eating behaviours in adolescents with diabetes compared to their peers without diabetes. The findings of this study may have the potential to inform future health promotion, prevention, and early intervention approaches for those with comorbid diabetes and disordered eating behaviours. Future longitudinal studies are required to evaluate disordered eating behaviours in those with diabetes over time in community-based samples
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