183 research outputs found
Total Cerebral Small Vessel Disease MRI Score Is Associated with Cognitive Decline in Executive Function in Patients with Hypertension
Objectives: Hypertension is a major risk factor for white matter hyperintensities (WMH), lacunes, cerebral microbleeds, and perivascular spaces, which are MRI markers of cerebral small vessel disease (SVD). Studies have shown associations between these individual MRI markers and cognitive functioning and decline. Recently, a âtotal SVD scoreâ was proposed in which the different MRI markers were combined into one measure of SVD, to capture total SVD-related brain damage. We investigated if this SVD score was associated with cognitive decline over 4 years in patients with hypertension. Methods: In this longitudinal cohort study, 130 hypertensive patients (91 patients with uncomplicated hypertension and 39 hypertensive patients with a lacunar stroke) were included. They underwent a neuropsychological assessment at baseline and after 4 years. The presence of WMH, lacunes, cerebral microbleeds, and perivascular spaces were rated on baseline MRI. Presence of each individual marker was added to calculate the total SVD score (range 0â4) in each patient. Results: Uncorrected linear regression analyses showed associations between SVD score and decline in overall cognition (p = 0.017), executive functioning (p < 0.001) and information processing speed (p = 0.037), but not with memory (p = 0.911). The association between SVD score and decline in overall cognition and executive function remained significant after adjustment for age, sex, education, anxiety and depression score, potential vascular risk factors, patient group, and baseline cognitive performance. Conclusion: Our study shows that a total SVD score can predict cognitive decline, specifically in executive function, over 4 years in hypertensive patients. This emphasizes the importance of considering total brain damage due to SVD
Charged-Particle Multiplicities in Charged-Current Neutrino-- and Anti-Neutrino--Nucleus Interactions
The CHORUS experiment, designed to search for
oscillations, consists of a nuclear emulsion target and electronic detectors.
In this paper, results on the production of charged particles in a small sample
of charged-current neutrino-- and anti-neutrino--nucleus interactions at high
energy are presented. For each event, the emission angle and the ionization
features of the charged particles produced in the interaction are recorded,
while the standard kinematic variables are reconstructed using the electronic
detectors. The average multiplicities for charged tracks, the pseudo-rapidity
distributions, the dispersion in the multiplicity of charged particles and the
KNO scaling are studied in different kinematical regions. A study of
quasi-elastic topologies performed for the first time in nuclear emulsions is
also reported. The results are presented in a form suitable for use in the
validation of Monte Carlo generators of neutrino--nucleus interactions.Comment: 17 pages, 5 figure
The trigger system of the CHORUS experiment
A new apparatus for detection of oscillation has been successfully constructed and operated by the CHORUS Collaboration for the CERN-WA95 experiment. The design , implementation and performance of the electronic trigger system is described. A trigger efficiency of 99 was measured for charged current events and 90 for neutral current e vents
The data acquisition system of the CHORUS experiment
In the years 1994-1998 the CHORUS Collaboration has recorded data in the CERN WA95 experiment. Here we describe the data acquisition system that has been used, featuring concurrent hierarchical state machines, a remote operating system, a buffer manager, a dispatcher, a control panel and a supervisor
The data acquisition system of the CHORUS experiment
In the years 1994--1998 the CHORUS Collaboration has recorded data in the CERN WA95 experiment. Here we describe the data acquisition system that has been used, featuring concurrent hierarchical state machines, a remote operating system, a buffer manager, a dispatcher, a control panel and a supervisor
Observation of weak neutral current neutrino production of
Observation of \jpsi production by neutrinos in the calorimeter of the CHORUS detector exposed to the CERN SPS wide-band \numu beam is reported. A spectrum-averaged cross-section = (6.3 3.0) is obtained for 20 GeV 200 GeV. The data are compared with the theoretical model based on the QCD Z-gluon fusion mechanism
The CHORUS neutrino oscillation search experiment
The CHORUS experiment has successfully finished run I (320~000 recorded \numu\ CC in 94/95) and performed half of run II (225~000 \numu\ CC in 96). The analysis chain was exercised on a small data sample for the muonic \tdecay\ search using for the first time fully automatic emulsion scanning. This pilot analysis, resulting in a limit \sintth \leq 3 \cdot 10^{-2}, confirms that the CHORUS proposal sensitivity (\sintth \leq 3 \cdot 10^{-4}) is within reach in two years
Glycemia but not the Metabolic Syndrome is Associated with Cognitive Decline: Findings from the European Male Ageing Study
© 2017 American Association for Geriatric Psychiatry. Objective Previous research has indicated that components of the metabolic syndrome (MetS), such as hyperglycemia and hypertension, are negatively associated with cognition. However, evidence that MetS itself is related to cognitive performance has been inconsistent. This longitudinal study investigates whether MetS or its components affect cognitive decline in aging men and whether any interaction with inflammation exists. Methods Over a mean of 4.4 years (SDâ±â0.3), men aged 40â79 years from the multicenter European Male Ageing Study were recruited. Cognitive functioning was assessed using the Rey-Osterrieth Complex Figure (ROCF), the Camden Topographical Recognition Memory (CTRM) task, and the Digit Symbol Substitution Test (DSST). High-sensitivity C-reactive protein (hs-CRP) levels were measured using a chemiluminescent immunometric assay. Results Overall, 1,913 participants contributed data to the ROCF analyses and 1,965 subjects contributed to the CTRM and DSST analyses. In multiple regression models the presence of baseline MetS was not associated with cognitive decline over time (pâ > â0.05). However, logistic ordinal regressions indicated that high glucose levels were related to a greater risk of decline on the ROCF Copy (ÎČâ=ââ0.42, pâ < â0.05) and the DSST (ÎČâ=ââ0.39, pâ < â0.001). There was neither a main effect of hs-CRP levels nor an interaction effect of hs-CRP and MetS at baseline on cognitive decline. Conclusion No evidence was found for a relationship between MetS or inflammation and cognitive decline in this sample of aging men. However, glycemia was negatively associated with visuoconstructional abilities and processing speed
Detection and reconstruction of short-lived particles produced by neutrino interactions in emulsion
In this dissertation, several different topics related to the chorus experiment are pre- sented. The chorus experiment has been used to study neutrino oscillations using the neutrino beam at cern. The neutrino oscillation hypothesis provided an explanation for the lower than expected fluxes of solar and atmospheric neutrinos. There are three neutrino species in nature corresponding to different weak eigenstates, namely, the elec- tron neutrino (Îœe ), the muon neutrino (ΜΌ ), and the tau neutrino (ÎœÏ ). The lower fluxes could be interpreted as spontaneous oscillations between electron and muon neutrinos and between muon and tau neutrinos. The chorus experiment was designed to detect oscillation of muon neutrinos into tau neutrinos with small mixing probability down to 2 · 10â4 and a mass difference square between ΜΌ and ÎœÏ larger than 0.5 eV2 . In the last decade, several disappearance experiments have confirmed the neutrino oscillation hypothesis and showed that oscillations occur between mass eigenstates with mass differences of 8 · 10â5 eV2 and 2.5 · 10â3 eV2 . The observed oscillations correspond to almost maximal mixing probability. Current and future efforts focus on detecting the remaining sub-dominant mixing. In the chorus experiment, one looks for the typical decay signature of a Ï particle in a large stack of nuclear emulsion plates. Emulsion can record with very high resolution the tracks and decays of short-lived particles, like Ï leptons and charmed mesons. A hybrid setup is used consisting of electronic detectors downstream of a 770 kg emulsion target. The electronic detectors consist of an accurate tracking station followed by a hadron spectrometer, a calorimeter, and a muon spectrometer. These detectors are used to measure particle momenta and to select one track per event for scanning the emulsion. Hybrid detectors combined with automated microscopes have greatly increased the amount of emulsion that can be scanned and the information that can be extracted. The fken laboratory in Nagoya developed designated hardware that can find a track with known angle in a 100 ÎŒm slice of emulsion. Further upgraded new hardware can find all tracks with slopes within a given angular range. The hardware is used to locate the neutrino vertex by following an electronically measured track from one plate to the next. The new hardware is then used to reconstruct all tracks and vertices of the event. This is done by combining track segments found in the 100 ÎŒm upstream layers of the eight plates around the interaction point. The suppression of background in the chorus experiment relies on the measurement of hadron momenta in the hadron spectrometer. A honeycomb drift-tube tracker was added to the detector to improve this measurement. This made it possible to reconstruct independently 3-d track segments in the hadron spectrometer. This improved the uncer- tainty on hadron momenta from âp/p = 0.352 + 0.38p/GeV to 0.352 + 0.25p/GeV, where the constant term is due to multiple scattering. The read-out of this detector is based on a continuous sampling of the overâthreshold signal of all wires. Because all transitions of a wireâs signal are recorded, both leading edge and pulse length can be recovered. The bit-stream of samples is stored in four phases in separate memory banks. Failure of some memory banks does not destroy the hit information but only lowers its timing accuracy. summary A new automatic emulsion scanning system was developed at cern. For this, new microscope optics with a large field of view were deployed and emulsion scanning was implemented in software. Using software for track finding in emulsion images requires an algorithm capable of handling of the order of 105 3-d hits in a few seconds. An algorithm was developed that searches a network of connected hits. The connection graph links hits in close proximity with a predefined restriction. In this case, the link should possibly be part of a track. This graph is created by sorting the hits in k -dimensional space using a specially designed ordered container with logarithmic search time. The track-finding algorithm considers any connection between two hits as a possible track and builds longer segments using a limited depth-first search of the connection graph. Although originally written for track finding in emulsion, the track-finding algorithm can work in any dimension and is decoupled from the actual hit and track model. The track model and the acceptance of hits in a track are handled by a specific implementation of an abstract acceptance class. The track-finding implementation has been used to find bent tracks in the harp time-projection chamber. In the chorus emulsion application, it has enabled improvements in the vertex location efficiency. It can also be used to reduce human confirmation of secondary vertices by applying it to data taken over the full emulsion thickness. An emulsion-specific algorithm was developed to look for tracks with a known direction. The algorithm is based on moving hits along the track direction and summing the number of hits in its angular acceptance region. Searching for hits in these acceptance regions can be done in logarithmic time using the aforementioned containers. The track-finding algorithm is then used to verify the existence of a track in the small volumes defined by a track-trigger sum over threshold. The k -d space ordering containers have been used throughout the work described in this dissertation, for example in several alignment procedures. The emulsion volume, scanned around the neutrino vertex, defines a decay space for short-lived particles. The maximum decay length is about 4.5 mm along the beam di- rection. In the chorus experiment, 1048 charged-current ΜΌ interactions, identified by a ÎŒâ from the primary vertex, with a secondary decay vertex from a D0 meson have been reconstructed. These events were used to study Dâ+ resonance production. The decay Dâ+ â D0 Ï + can be identified using the Ï + momentum measured in the hadron spectrometer and the direction of both the D0 and Ï + measured in the emulsion. From the observed 22.1 ± 5.5 events, the cross-section ratio for hadronization of a charm quark into Dâ+ and D0 is derived: Ï (Dâ+ ) /Ï D0 = 0.38 ± 0.09(stat) ± 0.05(syst). The production cross-section of Dâ+ with respect to the total charged-current cross-section is Ï (Dâ+ ) /Ï (CC) = [1.02 ± 0.25(stat) ± 0.15(syst)] %
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