212 research outputs found
The use of a SQUID magnetometer for middle ear research
A new technique is described for the measurement of vibrations in the temporal bones of an isolated middle ear. The precise recording of vibrations in the middle ear is of importance for the construction and improvement of a middle ear prosthesis.1 The method of measurement is based on a transformation of mechanical vibrations into magnetic flux variations. This is performed by attaching a small piece of permanent magnetic material to the eardrum or middle ear ossicles. The magnetic flux variations caused by vibrations of the eardrum or ossicles during application of sound can be measured by means of a SQUID magnetometer.\ud
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Measurements showed that it is possible to measure vibratory displacement amplitudes of the eardrum down to about 10−10 m in a frequency range between 200 Hz and 10 kHz, although the acoustical and magnetometer conditions were not optimal. The method offers several advantages compared to already existing methods.2–5,
Ensayo clínico aleatorizado de una intervención intensiva sobre los estilos de vida de pacientes con hiperfibrinogenemia en prevención primaria de las enfermedades cardiovasculares en el ámbito de la atención primaria de salud
ObjetivosEstudiar el efecto de un programa intensivo de modificación del estilo de vida en los valores de fibrinógeno plasmático en pacientes sin enfermedad cardiovascular, con fibrinógeno elevado y valores normales de colesterol. Analizar si el efecto sobre el fibrinógeno es independiente del efecto sobre los lípidos.DiseñoEnsayo clínico controlado y aleatorizado.EmplazamientoOnce áreas básicas de L’Hospitalet de Llobregat y Barcelona.ParticipantesSe incluirá a 436 pacientes, 218 en cada grupo, de 35-75 años, sin enfermedad cardiovascular (cardiopatía isquémica, accidente cerebrovascular y arteriopatía periférica) con hiperfibrinogenemia (fibrinógeno > 300 mg/dl) y colesterol plasmático < 250 mg/dl.IntervencionesUn grupo de pacientes recibirá una intervención intensiva (en frecuencia e intensidad del consejo y tratamiento) sobre cambios de estilo de vida: dejar de fumar, dieta hipocalórica en caso de sobrepeso u obesidad y ejercicio físico. El seguimento del grupo intervención se realizará cada 2 meses. El grupo control seguirá los cuidados habituales.MedicionesSe determinarán los valores de fibrinógeno plasmático. Además, se registrarán otros acontecimientos de interés (modificación de los factores de riesgo, cambios en la calidad de vida, acontecimientos cardiovasculares y muerte) durante un seguimiento de 2 años.DiscusiónLa instauración de una intervención intensiva de prevención primaria (cambios de estilo de vida) en los pacientes que presentan hiperfibrinogenemia podría ser una medida más eficaz que la intervención habitual para reducir las cifras de fibrinógeno plasmático. Además, estas medidas podrían traducirse en una disminución del riesgo cardiovascular y en una mejora de la calidad de vida del paciente.ObjectivesTo study the effect of an intensive programme to modify life-style on levels of plasma fibrinogen in patients without cardiovascular pathology, with high fibrinogen and normal cholesterol levels. To analyse whether the effect on fibrinogen is independent, or otherwise, of the effect on lipids.DesignRandomised clinical trial with a control.Setting11 health districts in L’Hospitalet de Llobregat and Barcelona.Participants436 patients will be included, 218 individuals between 35 and 75 years old in each group, and without cardiovascular pathology (ischaemic cardiopathy, cerebral vascular accident or peripheral arteriopathy), with hyperfibrinogenaemia (fibrinogen ›300 mg/dL) and with plasma control ‹250 mg/dL.InterventionsOne group of patients will receive an intensive intervention (in frequency and intensity of counselling and treatment) for life-style changes, i.e. stopping smoking, low-calorie diet in case of overweight or obesity, and physical exercise. The follow-up of the intervention group will be every 2 months. The control group will follow customary treatments.MeasurementsLevels of plasma fibrinogen. In addition, other relevant events will be recorded over a 2-year monitoring period: modification of risk factors, changes in quality of life, cardiovascular events or death.DiscussionThe introduction of an intensive primary prevention intervention (life-style changes) in patients with hyperfibrinogenaemia could be a more effective measure than the habitual intervention for reducing plasma fibrinogen figures. In addition, these measures could be translated into a reduction of cardiovascular risk and an improvement in the patient́s quality of life
Ototopical drops containing a novel antibacterial synthetic peptide: safety and efficacy in adults with chronic suppurative otitis media
ObjectiveChronic suppurative otitis media (CSOM) is a chronic infectious disease with worldwide prevalence that causes hearing loss and decreased quality of life. As current (antibiotic) treatments often unsuccessful and antibiotic resistance is emerging, alternative agents and/or strategies are urgently needed. We considered the synthetic antimicrobial and anti-biofilm peptide P60.4Ac to be an interesting candidate because it also displays anti-inflammatory activities including lipopolysaccharide-neutralizing activity. The aim of the present study was to investigate the safety and efficacy of ototopical drops containing P60.4Ac in adults with CSOM without cholesteatoma.MethodsWe conducted a range-finding study in 16 subjects followed by a randomized, double blinded, placebo-controlled, multicentre phase IIa study in 34 subjects. P60.4Ac-containing ototopical drops or placebo drops were applied twice a day for 2 weeks and adverse events (AEs) and medication use were recorded. Laboratory tests, swabs from the middle ear and throat for bacterial cultures, and audiometry were performed at intervals up to 10 weeks after therapy. Response to treatment was assessed by blinded symptom scoring on otoscopy.ResultsApplication of P60.4Ac-containing ototopical drops (0.25-2.0 mg of peptide/ml) in the ear canal of patients suffering from CSOM was found to be safe and well-tolerated. The optimal dose (0.5 mg of peptide/ml) was selected for the subsequent phase IIa study. Safety evaluation revealed only a few AEs that were unlikely related to study treatment and all, except one, were of mild to moderate intensity. In addition to this excellent safety profile, P60.4Ac ototopical drops resulted in a treatment success in 47% of cases versus 6% in the placebo group.ConclusionThe efficacy/safety balance assessed in the present study provides a compelling justification for continued clinical development of P60.4Ac in therapy-resistant CSOM.Development and application of statistical models for medical scientific researc
A First Search for coincident Gravitational Waves and High Energy Neutrinos using LIGO, Virgo and ANTARES data from 2007
We present the results of the first search for gravitational wave bursts
associated with high energy neutrinos. Together, these messengers could reveal
new, hidden sources that are not observed by conventional photon astronomy,
particularly at high energy. Our search uses neutrinos detected by the
underwater neutrino telescope ANTARES in its 5 line configuration during the
period January - September 2007, which coincided with the fifth and first
science runs of LIGO and Virgo, respectively. The LIGO-Virgo data were analysed
for candidate gravitational-wave signals coincident in time and direction with
the neutrino events. No significant coincident events were observed. We place
limits on the density of joint high energy neutrino - gravitational wave
emission events in the local universe, and compare them with densities of
merger and core-collapse events.Comment: 19 pages, 8 figures, science summary page at
http://www.ligo.org/science/Publication-S5LV_ANTARES/index.php. Public access
area to figures, tables at
https://dcc.ligo.org/cgi-bin/DocDB/ShowDocument?docid=p120000
Fragmentation and Multifragmentation of 10.6A GeV Gold Nuclei
We present the results of a study performed on the interactions of 10.6A GeV
gold nuclei in nuclear emulsions. In a minimum bias sample of 1311 interac-
tions, 5260 helium nuclei and 2622 heavy fragments were observed as Au projec-
tile fragments. The experimental data are analyzed with particular emphasis of
target separation interactions in emulsions and study of criticalexponents.
Multiplicity distributions of the fast-moving projectile fragments are inves-
tigated. Charged fragment moments, conditional moments as well as two and three
-body asymmetries of the fast moving projectile particles are determined in
terms of the total charge remaining bound in the multiply charged projectile
fragments. Some differences in the average yields of helium nuclei and heavier
fragments are observed, which may be attributed to a target effect. However,
two and three-body asymmetries and conditional moments indicate that the
breakup mechanism of the projectile seems to be independent of target mass. We
looked for evidence of critical point observable in finite nuclei by study the
resulting charged fragments distributions. We have obtained the values for the
critical exponents gamma, beta and tau and compare our results with those at
lower energy experiment (1.0A GeV data). The values suggest that a phase
transition like behavior, is observed.Comment: latex, revtex, 28 pages, 12 figures, 3tables, submitted to Europysics
Journal
Search for gravitational waves from Scorpius X-1 in the second Advanced LIGO observing run with an improved hidden Markov model
We present results from a semicoherent search for continuous gravitational waves from the low-mass x-ray binary Scorpius X-1, using a hidden Markov model (HMM) to track spin wandering. This search improves on previous HMM-based searches of LIGO data by using an improved frequency domain matched filter, the J-statistic, and by analyzing data from Advanced LIGO's second observing run. In the frequency range searched, from 60 to 650 Hz, we find no evidence of gravitational radiation. At 194.6 Hz, the most sensitive search frequency, we report an upper limit on gravitational wave strain (at 95% confidence) of h095%=3.47×10-25 when marginalizing over source inclination angle. This is the most sensitive search for Scorpius X-1, to date, that is specifically designed to be robust in the presence of spin wandering. © 2019 American Physical Society
All-sky search for long-duration gravitational wave transients with initial LIGO
We present the results of a search for long-duration gravitational wave transients in two sets of data collected by the LIGO Hanford and LIGO Livingston detectors between November 5, 2005 and September 30, 2007, and July 7, 2009 and October 20, 2010, with a total observational time of 283.0 days and 132.9 days, respectively. The search targets gravitational wave transients of duration 10-500 s in a frequency band of 40-1000 Hz, with minimal assumptions about the signal waveform, polarization, source direction, or time of occurrence. All candidate triggers were consistent with the expected background; as a result we set 90% confidence upper limits on the rate of long-duration gravitational wave transients for different types of gravitational wave signals. For signals from black hole accretion disk instabilities, we set upper limits on the source rate density between 3.4×10-5 and 9.4×10-4 Mpc-3 yr-1 at 90% confidence. These are the first results from an all-sky search for unmodeled long-duration transient gravitational waves. © 2016 American Physical Society
All-sky search for long-duration gravitational wave transients with initial LIGO
We present the results of a search for long-duration gravitational wave transients in two sets of data collected by the LIGO Hanford and LIGO Livingston detectors between November 5, 2005 and September 30, 2007, and July 7, 2009 and October 20, 2010, with a total observational time of 283.0 days and 132.9 days, respectively. The search targets gravitational wave transients of duration 10-500 s in a frequency band of 40-1000 Hz, with minimal assumptions about the signal waveform, polarization, source direction, or time of occurrence. All candidate triggers were consistent with the expected background; as a result we set 90% confidence upper limits on the rate of long-duration gravitational wave transients for different types of gravitational wave signals. For signals from black hole accretion disk instabilities, we set upper limits on the source rate density between 3.4×10-5 and 9.4×10-4 Mpc-3 yr-1 at 90% confidence. These are the first results from an all-sky search for unmodeled long-duration transient gravitational waves. © 2016 American Physical Society
Search for Tensor, Vector, and Scalar Polarizations in the Stochastic Gravitational-Wave Background
The detection of gravitational waves with Advanced LIGO and Advanced Virgo has enabled novel tests of general relativity, including direct study of the polarization of gravitational waves. While general relativity allows for only two tensor gravitational-wave polarizations, general metric theories can additionally predict two vector and two scalar polarizations. The polarization of gravitational waves is encoded in the spectral shape of the stochastic gravitational-wave background, formed by the superposition of cosmological and individually unresolved astrophysical sources. Using data recorded by Advanced LIGO during its first observing run, we search for a stochastic background of generically polarized gravitational waves. We find no evidence for a background of any polarization, and place the first direct bounds on the contributions of vector and scalar polarizations to the stochastic background. Under log-uniform priors for the energy in each polarization, we limit the energy densities of tensor, vector, and scalar modes at 95% credibility to Ω0T<5.58×10-8, Ω0V<6.35×10-8, and Ω0S<1.08×10-7 at a reference frequency f0=25 Hz. © 2018 American Physical Society
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