77 research outputs found
Search for Gravitational Waves from Intermediate Mass Binary Black Holes
We present the results of a weakly modeled burst search for gravitational
waves from mergers of non-spinning intermediate mass black holes (IMBH) in the
total mass range 100--450 solar masses and with the component mass ratios
between 1:1 and 4:1. The search was conducted on data collected by the LIGO and
Virgo detectors between November of 2005 and October of 2007. No plausible
signals were observed by the search which constrains the astrophysical rates of
the IMBH mergers as a function of the component masses. In the most efficiently
detected bin centered on 88+88 solar masses, for non-spinning sources, the rate
density upper limit is 0.13 per Mpc^3 per Myr at the 90% confidence level.Comment: 13 pages, 4 figures: data for plots and archived public version at
https://dcc.ligo.org/cgi-bin/DocDB/ShowDocument?docid=62326, see also the
public announcement at http://www.ligo.org/science/Publication-S5IMBH
All-sky search for gravitational-wave bursts in the second joint LIGO-Virgo run
We present results from a search for gravitational-wave bursts in the data
collected by the LIGO and Virgo detectors between July 7, 2009 and October 20,
2010: data are analyzed when at least two of the three LIGO-Virgo detectors are
in coincident operation, with a total observation time of 207 days. The
analysis searches for transients of duration < 1 s over the frequency band
64-5000 Hz, without other assumptions on the signal waveform, polarization,
direction or occurrence time. All identified events are consistent with the
expected accidental background. We set frequentist upper limits on the rate of
gravitational-wave bursts by combining this search with the previous LIGO-Virgo
search on the data collected between November 2005 and October 2007. The upper
limit on the rate of strong gravitational-wave bursts at the Earth is 1.3
events per year at 90% confidence. We also present upper limits on source rate
density per year and Mpc^3 for sample populations of standard-candle sources.
As in the previous joint run, typical sensitivities of the search in terms of
the root-sum-squared strain amplitude for these waveforms lie in the range 5
10^-22 Hz^-1/2 to 1 10^-20 Hz^-1/2. The combination of the two joint runs
entails the most sensitive all-sky search for generic gravitational-wave bursts
and synthesizes the results achieved by the initial generation of
interferometric detectors.Comment: 15 pages, 7 figures: data for plots and archived public version at
https://dcc.ligo.org/cgi-bin/DocDB/ShowDocument?docid=70814&version=19, see
also the public announcement at
http://www.ligo.org/science/Publication-S6BurstAllSky
Does continuous positive airway pressure treatment affect autonomic nervous system in patients with severe obstructive sleep apnea?
OBJECTIVE:
This study is aimed at evaluating whether Continuous Positive Airway Pressure treatment (CPAP) may affect autonomic nervous system (ANS) in male patients with severe obstructive sleep apnea (OSAS).
METHODS:
We compared autonomic symptoms of de novo severe OSAS patients, OSAS patients on chronic CPAP treatment and healthy controls, using the Scales for Outcome in Parkinson disease-Autonomic (SCOPA-AUT) questionnaire. All groups underwent cardiovascular function tests including head-up tilt test (HUTT), Valsalva maneuver, deep breathing, hand grip and cold face tests. Statistical significance was set at p < 0.05.
RESULTS:
Twelve de novo severe OSAS patients, 17 male OSAS on CPAP and 14 controls were studied. The mean SCOPA-AUT total score was significantly higher in de novo OSAS patients compared with controls. Regarding the distinct domains, both de novo OSAS and CPAP group had abnormalities in respect of controls in urinary sphere. In supine rest condition the baseline values of systolic blood pressure were significantly increased in untreated OSAS patients compared with controls, whereas the basal values of diastolic blood pressure were significantly higher in CPAP patients with respect to controls. After ten min of HUTT, diastolic blood pressure changes were significantly higher in controls compared to both OSAS groups. Untreated OSAS patients showed significant different responses at deep breathing compared to controls. Both OSAS groups had a significant reduction of reflex bradycardia at cold face test.
CONCLUSIONS:
Our study shows that both treated and untreated OSAS patients complain of subjective autonomic symptoms like other sleep disorders reinforcing the close relationship between sleep and autonomic activity. Furthermore, cardiovascular reflexes indicate a tendency to hypertension and a reduced sensitivity to stimuli during wakefulness even in OSA patients on CPAP treatment, suggesting potentially permanent autonomic function deficits
Chronic dopaminergic treatment in restless legs syndrome: Does it affect the autonomic nervous system?
Objective: The link between the autonomic nervous system and restless legs syndrome (RLS) has been recently postulated. Since dopaminergic agents are used as first-line treatment for RLS, the purpose of our study is to verify whether chronic pramipexole treatment could influence the autonomic control of cardiovascular reflexes and heart rate variability (HRV) in RLS during wakefulness. Methods: Consecutive drug naive RLS patients underwent polysomnography (PSG), subjective scales, and cardiovascular function tests including head-up tilt test (HUTT), Valsalva maneuver, deep breathing, handgrip and cold face before and after 3-month pramipexole therapy. HRV analysis was performed in the frequency domain using both autoregressive and fast Fourier transform algorithms in rest supine condition and during HUTT. Results: Twenty RLS patients reported a significant reduction of RLS symptoms after pramipexole treatment, while PSG did not show significant improvements except for periodic limb movement index. Pramipexole induced a trend to a lower systolic blood pressure and a significant higher variation of systolic and diastolic blood pressure at HUTT. Cardiovascular responses to the other tests were unchanged. No significant differences in HRV spectral analysis between drug naive and treated patients were observed. Moreover, the within-group analysis of HRV between orthostatic and supine position did not show any significant change in sympathetic and parasympathetic components both in the drug naive and pramipexole groups. Conclusions: Chronic pramipexole treatment does not seem to affect autonomic balance during wakefulness. Considering that neither PSG data nor autonomic parameters are significantly modified by pramipexole, we hypothesize a non-dopaminergic autonomic dysfunction in RLS
Refinement of the SPG9 locus on chromosome 10q23.3-24.2 and exclusion of candidate genes.
BACKGROUND AND PURPOSE: The hereditary spastic paraplegias (HSPs) are a heterogeneous group of neurodegenerative disorders, characterized by a progressive spasticity of the lower limbs. So far, 33 different loci (SPGs) have been mapped and the 15 genes responsible have been identified. We mapped a locus responsible for a form of spastic paraplegia, complicated by bilateral cataracts, gastroesophageal reflux with persisting vomiting and amyotrophy to chromosome 10q23.3-q24.2, in an Italian family. The critical region was in a 12 cm chromosomal interval between markers D10S564 and D10S603 (SPG9, MIM601162). In the same region, two other forms of HSP have been recently mapped: SPG27 and SPG33. In the latter case, the gene responsible has been identified. MATERIALS AND METHODS: To better characterize this region, we genotyped individuals from SPG9-linked families using additional markers and reduced the candidate region to a 4.8 Mb, excluding several genes by positional cloning. RESULTS: The refined SPG9 locus is positioned completely within SPG27 and does not include the SPG33 gene. DISCUSSION: Fifty-two transcripts are present in the refined critical region and 25 strong candidates have been excluded as disease causing genes by direct sequencing. Six of them were also excluded as responsible for SPG27
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