626 research outputs found
Assessing Cognitive-Motor Integration in Middle-Aged Athletes: The Effects of Dementia Risk & Concussion
We investigated the relationship between dementia risk and concussion history in a physically active, middle-aged adult population (between the ages of 30 and 65). These participants either had one of the following: a family history of Alzheimer's disease, a history of concussion(s), both histories, or no histories. We know from previous work in our lab that those with dementia or concussion history performed poorly when asked to make skilled movements when having to think simultaneously (cognitive-motor integration, CMI). Here we conducted a cognitive-motor assessment on middle-aged recreational athletes (male and female) using a computer tablet-based task. Data collected included kinematics such as reaction and movement time, path length, accuracy, precision. We predicted that those who either have a concussion history and/or family history of dementia will perform poorly when compared to controls, and that this effect will be exacerbated in those individuals with both factors. On an exploratory basis, these data will provide insight into lifestyle factors that may affect cognitive-motor integration in middle-aged adults, an ability often important for functioning safely at work and sport. We found that those with both histories have impairments in movement pathlength when compared to those with only concussion history and no histories, suggesting an additive effect of both histories on CMI performance. But activity level does not seem to be protective with regards to CMI decline in those with brain health issues
Probing the evolution of galaxy clusters with the SZ effect
In galaxy clusters the thermal Sunyaev-Zel'dovich (SZ) effect from the hot intracluster medium (ICM) provides a direct, self-contained measure of the pressure integrated over crossing lines of sight, that is intrinsically independent of redshift and well suited for evolutionary studies. We show in detail how the size of the effect and its pattern on the sky plane are directly related to the entropy levels in the ICM, and how they characterize the cluster cores and outskirts independently. We find that at redshifts z 72 0.3 the signals to be expected in the cores considerably exceed those detected at 10' resolution with the Planck satellite. We propose that at 1' resolutions as implemented on recent ground instrumentation for mapping features in individual clusters, the average patterns of the SZ signals can provide a direct and effective way to find and count cool, low-entropy cores and hot, high-entropy outskirts out to z ~ 2. Such counts will tell the timing and the mode of the processes that drive the evolution of the ICM from the distant to the local cluster population
Intracluster Entropy from Joint X-ray and Sunyaev-Zel'dovich Observations
The temperature and density of the hot diffuse medium pervading galaxy groups and clusters combine into one significant quantity, the entropy. Here we express the entropy levels and profiles in model-independent forms by joining two observables, the X-ray luminosity and the change in the CMB intensity due to the Sunyaev-Zel'dovich (SZ) effect. Thus we present both global scaling relations for the entropy levels from clusters and groups, and a simple expression yielding the entropy profiles in individual clusters from resolved X-ray surface brightness and SZ spatial distributions. We propose that our approach provides two useful tools for comparing large data samples with models, in order to probe the processes that govern the thermal state of the hot intracluster medium. The feasibility of using such a diagnostic for the entropy is quantitatively assessed, based on current X-ray and upcoming SZ measurements
Use of balloon catheter dilation and steroid-eluting stent in light and severe rhinosinusitis of frontal sinus: a multicenter retrospective randomized study
OBJECTIVE: Frontal sinus surgery has an increased rate of re-stenosis, if compared to other sinuses, that mainly depends on recurrent inflammation and abnormal scarring at the frontal recess; its reduction represents one of the keys of therapeutic success. Balloon catheter dilation (BCD) and implantable sinus stents/spacers represent strategies to improve sinus ventilation respecting the integrity of mucosa and reducing abnormal post-surgical scarring. The purpose of this study is to evaluate the effectiveness, safety and correct indication for the use of BCD and a non-absorbable stent (Relieva Stratus™ MicroFlow spacer) in the management of chronic rhinosinusitis (CRS) of the frontal sinus. PATIENTS AND METHODS: In this multicentric retrospective study we included a population of 76 frontal sinuses with non-polypoid CRS. Forty-one frontal sinuses were treated with BCD alone and 35 with BCD + Spacer. We analysed both radiological (Lund-McKay CT scoring modified by Zienrich) and symptomatologic results (SNOT-20 questionnaire) before surgery and after 12 months, dividing patients in two main groups: group “L” (light/mild frontal CRS) and group “S” (moderate/severe frontal CRS). RESULTS: Our results confirm a good safety and effectiveness of BCD in management of frontal CRS and show a good safety, although without significant effectiveness, of Relieva Stratus™ MicroFlow spacer when added to BCD in the management of light and severe frontal CRS. CONCLUSIONS: BCD is an option in management of frontal CRS; the use of stents/spacers could become a new and effective tool in management of CSR, both in addition to standard therapies and in patients where the use of systemic drugs is contraindicated
The Blazar PG 1553+113 as a Binary System of Supermassive Black Holes
The BL Lac PG 1553+113 has been continuously monitored in gamma rays with
Fermi-LAT for over 9 years. Its updated light curve now includes 5 iterations
of a main pattern comprising a high peak and a longer trough, with a period P
\sim 2.2 yr. Our analysis of 2015-2017 data confirms the occurrence in January
2017 of a new peak fitting in the previous trend. In addition, we identify
secondary peaks ("twin peaks") that occur in closely symmetric pairs on both
sides of most main peaks, including the last one; their occurrence is supported
by correlated X-ray outbursts. We stress that the above features strongly point
to binary dynamics in a system of two black holes (BHs) of some 10^8 and 10^7
M_sun. At periastron the smaller BH periodically stresses the jet j_1 launched
by the heavier companion, and triggers MHD-kinetic tearing instabilities. These
lead to magnetic reconnections and to acceleration of electrons that produce
synchrotron emission from the optical to X-ray bands, and inverse Compton
scattering into the GeV range. For the origin of the twin peaks we discuss two
possibilities: a single-jet model, based on added instabilities induced in j_1
by the smaller companion BH on its inner orbital arc; and a two-jet model with
the smaller BH supporting its own, precessing jet j_2 that contributes lower,
specific GeV emissions. Such behaviors combining time stability with amplitude
variations betray plasma instabilities driven in either jet by binary dynamics,
and can provide a double signature of the long-sought supermassive BH binaries.Comment: 15 pages, 5 figures, accepeted by ApJ on December 21, 201
Functional Connectivity Substrates for tDCS Response in Minimally Conscious State Patients
peer reviewedTranscranial direct current stimulation (tDCS) is a non-invasive technique recently employed in disorders of consciousness, and determining a transitory recovery of signs of consciousness in almost half of minimally conscious state (MCS) patients. Although the rising evidences about its possible role in the treatment of many neurological and psychiatric conditions exist, no evidences exist about brain functional connectivity substrates underlying tDCS response. We retrospectively evaluated resting state functional Magnetic Resonance Imaging (fMRI) of 16 sub-acute and chronic MCS patients (6 tDCS responders) who successively received a single left dorsolateral prefrontal cortex (DLPFC) tDCS in a double-blind randomized cross-over trial. A seed-based approach for regions of left extrinsic control network (ECN) and default-mode network (DMN) was performed. tDCS responders showed an increased left intra-network connectivity for regions co-activated with left DLPFC, and significantly with left inferior frontal gyrus. Non-responders (NR) MCS patients showed an increased connectivity between left DLPFC and midline cortical structures, including anterior cingulate cortex and precuneus. Our findings suggest that a prior high connectivity with regions belonging to ECN can facilitate transitory recovery of consciousness in a subgroup of MCS patients that underwent tDCS treatment. Therefore, resting state-fMRI could be very valuable in detecting the neuronal conditions necessary for tDCS to improve behavior in MCS
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