439 research outputs found
On the three-dimensional temporal spectrum of stretched vortices
The three-dimensional stability problem of a stretched stationary vortex is
addressed in this letter. More specifically, we prove that the discrete part of
the temporal spectrum is only associated with two-dimensional perturbations.Comment: 4 pages, RevTeX, submitted to PR
Suppression of Hydrogen Emission in an X-Class White-Light Solar Flare
We present unique NUV observations of a well-observed X-class flare from NOAA
12087 obtained at Ond\v{r}ejov Observatory. The flare shows a strong
white-light continuum but no detectable emission in the higher Balmer and Lyman
lines. RHESSI and Fermi observations indicate an extremely hard X-ray spectrum
and gamma-ray emission. We use the RADYN radiative hydrodynamic code to perform
two type of simulations. One where an energy of 3 x 10^11 erg/cm^2/s is
deposited by an electron beam with a spectral index of ~3 and a second where
the same energy is applied directly to the photosphere. The combination of
observations and simulations allow us to conclude that the white-light emission
and the suppression or complete lack of hydrogen emission lines is best
explained by a model where the dominant energy deposition layer is located in
the lower layers of the solar atmosphere rather than the chromosphere.Comment: 13 page
Forward Physics at the LHC (Elba 2010)
The papers review the main theoretical and experimental aspects of the
Forward Physics at the Large Hadron Collider
Bardet-Biedl Syndrome ciliopathy is linked to altered hematopoiesis and dysregulated self-tolerance
BardetâBiedl Syndrome (BBS) is a pleiotropic genetic disease caused by the dysfunction of primary cilia. The immune system of patients with ciliopathies has not been investigated. However, there are multiple indications that the impairment of the processes typically associated with cilia may have influence on the hematopoietic compartment and immunity. In this study, we analyze clinical data of BBS patients and corresponding mouse models carrying mutations in Bbs4 or Bbs18. We find that BBS patients have a higher prevalence of certain autoimmune diseases. Both BBS patients and animal models have altered red blood cell and platelet compartments, as well as elevated white blood cell levels. Some of the hematopoietic system alterations are associated with BBSâinduced obesity. Moreover, we observe that the development and homeostasis of B cells in mice is regulated by the transport complex BBSome, whose dysfunction is a common cause of BBS. The BBSome limits canonical WNT signaling and increases CXCL12 levels in bone marrow stromal cells. Taken together, our study reveals a connection between a ciliopathy and dysregulated immune and hematopoietic systems
\b{eta}-delayed three-proton decay of 31Ar
The beta decay of 31Ar, produced by fragmentation of a 36Ar beam at 880
MeV/nucleon, was investigated. Identified ions of 31Ar were stopped in a
gaseous time projection chamber with optical readout allowing to record decay
events with emission of protons. In addition to \b{eta}-delayed emission of one
and two protons we have clearly observed the beta-delayed three-proton branch.
The branching ratio for this channel in 31Ar is found to be 0.07(2)%.Comment: 5 pages, 3 figures, submitted to Physical Rev.
How Does Cryotherapy Effect Ankle Proprioception in Healthy Individuals?
Objectives: To investigate how a 15 minute Cryotherapy intervention effects proprioception by measuring Joint positional Sense (JPS) and static single legged balance. Design: Repeated measures design. Setting: Laboratory. Participants: Eighteen healthy university sports team students (11 males, 7 females) aged between 20-21 years. Main Outcome Measures: Participants were treated with 15 minutes Aircast Cryo-cuff. The subjectâs skin temperature was measured before and immediately after 15 minutes Cryotherapy treatment. Ankle active joint positional sense (A-JPS) and passive joint positional sense (P-JPS) was measured at pre-test, immediately post-test and 5 minutes post-test. Static balance was measured by Centre of Pressure (CoP) mean path length, medial-lateral (ML) CoP mean Deviation and anterior-posterior (AP) CoP mean Deviation and mean time-to-boundary (TtB) Minima for AP and ML directions. Results: No significant differences found for the variables of JPS and static single balance testing after 15 minutes Cryotherapy treatment. However, mean differences for CoP mean path length and ML mean deviation were shown to improve following Cryotherapy treatment, results not previously found in the literature. Conclusion: Results suggest that 15 minute Cryo-cuff treatment doesnât significantly affect proprioception. Although the effect of Cryotherapy on proprioception depends on cooling modality used, time frame applied and joint applied to
The LLP risk model: an individual risk prediction model for lung cancer
Using a model-based approach, we estimated the probability that an individual, with a specified combination of risk factors, would develop lung cancer within a 5-year period
Why do patients want to have their blood tested? A qualitative study of patient expectations in general practice
BACKGROUND: General practitioners often take their impression of patients' expectations into account in their decision to have blood tests done. It is commonly recommended to involve patients in decision-making during consultations. The study aimed to obtain detailed information on patients' expectations about blood tests. METHODS: Qualitative study among patients in waiting rooms of general practices. Each patient was presented with a short questionnaire about their preferences in terms of diagnostics. Patients who would like blood tests to be done were interviewed. RESULTS: Fifty-seven (26%) of the 224 respondents wanted blood tests. Twenty-two were interviewed. Patients overestimated the qualities of blood tests. Favourable test results were regarded as proof of good health. Patients regarded blood tests as a useful instrument to screen for serious disorders, and were confirmed in this belief by people in their social environment and by the media. Many patients expected their GP to take an active test ordering approach, though some indicated that they might be convinced if their GP proposed a wait-and-see policy. CONCLUSIONS: GPs' perceptions about patient expectations seem justified: patients appear to have high hopes for testing as a diagnostic tool. They expect diagnostic certainty without mistakes and a proof of good health. The question is whether it would be desirable to remove patients' misconceptions, allowing them to participate in policy decisions on the basis of sound information, or whether it would be better to leave the misconceptions uncontested, in order to retain the 'magic' of additional tests and reassure patients. We expect that clarifying the precise nature of patients' expectations by the GP may be helpful in creating a diagnostic strategy that satisfies both patients and GPs. GPs will have to balance the benefits of reassuring their patients by means of blood tests which may be unnecessary against the benefits of avoiding unnecessary tests. Further research is needed into the effects of different types of patient information and the effects of testing on satisfaction and anxiety
Two-Neutron Halo is Unveiled in ^{29}F
We report the measurement of reaction cross sections (Ï_{R}^{ex}) of ^{27,29}F with a carbon target at RIKEN. The unexpectedly large Ï_{R}^{ex} and derived matter radius identify ^{29}F as the heaviest two-neutron Borromean halo to date. The halo is attributed to neutrons occupying the 2p_{3/2} orbital, thereby vanishing the shell closure associated with the neutron number N=20. The results are explained by state-of-the-art shell model calculations. Coupled-cluster computations based on effective field theories of the strong nuclear force describe the matter radius of ^{27}F but are challenged for ^{29}F
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