1,538 research outputs found
A theorem for the beam splitter entangler
It is conjectured that the an entanglement output states from a beam splitter
requires the nonclassicality in the input state(M.S. Kim, W. Son, V. Buzek and
P. L. Knight, Phys. Rev. A, 65, 032323(2002)). Here we give a proof for this
conjecture.Comment: Two relevant literatures added. To appear in Phys. Rev.
Properties of a beam splitter entangler with Gaussian input states
An explicit formula is given for the quantity of entanglement in the output
state of a beam splitter, given the squeezed vacuum states input in each mode.Comment: To appear in Phys. Rev.
Listening to MEMS: An acoustic vibrometer
new way to characterize vibrating MEMS devices is presented. Using an acoustic particle velocity sensor the coupled sound field is measured, which is a measure for the movement of the MEMS device. We present several possible applications of this measurement method. It can be used as a read-out system for a mass flow sensor, and for characterization of in- and out-of-plane movements of MEMS devices. The method is an interesting alternative to laser scanning vibrometry due to its small size and low complexity; furthermore, it allows the user to `listen' directly to MEMS devices
Modified gravity without dark matter
On an empirical level, the most successful alternative to dark matter in
bound gravitational systems is the modified Newtonian dynamics, or MOND,
proposed by Milgrom. Here I discuss the attempts to formulate MOND as a
modification of General Relativity. I begin with a summary of the
phenomenological successes of MOND and then discuss the various covariant
theories that have been proposed as a basis for the idea. I show why these
proposals have led inevitably to a multi-field theory. I describe in some
detail TeVeS, the tensor-vector-scalar theory proposed by Bekenstein, and
discuss its successes and shortcomings. This lecture is primarily pedagogical
and directed to those with some, but not a deep, background in General
RelativityComment: 28 pages, 10 figures, lecture given at Third Aegean Summer School,
The Invisible Universe: Dark Matter and Dark Energy, minor errors corrected,
references update
Miniature large range multi-axis force-torque sensor for biomechanical applications
A miniature force sensor for the measurement of forces and moments at a human fingertip is designed and realized. Thin silicon pillars inside the sensor provide in-plane guidance for shear force measurement and provide the spring constant in normal direction. A corrugated silicon ring around the force sensitive area provides the spring constant in shear direction and seals the interior of the sensor. To detect all load components, capacitive read-out is used. A novel electrode pattern results in a large shear force sensitivity. The fingertip force sensor has a wide force range of up to 60 N in normal direction, ± 30 N in shear direction and a torque range of ± 25 N mm
Neurological Dysfunction in Coeliac Disease and Non-Coeliac Gluten Sensitivity
OBJECTIVES: Non-coeliac gluten sensitivity (NCGS) refers to patients with primarily gastrointestinal symptoms
without enteropathy that symptomatically benefi t from gluten-free diet (GFD). Little is known about
its pathophysiology, propensity to neurological manifestations, and if these differ from patients with
coeliac disease (CD). We investigated the clinical and immunological characteristics of patients
presenting with neurological manifestations with CD and those with NCGS.
METHODS: We compared clinical, neurophysiological, and imaging data of patients with CD and NCGS
presenting with neurological dysfunction assessed and followed up regularly over a period of
20 years.
RESULTS: Out of 700 patients, 562 were included. Exclusion criteria included no bowel biopsy to confi rm
CD, no HLA type available, and failure to adhere to GFD. All patients presented with neurological
dysfunction and had circulating anti-gliadin antibodies. Out of 562 patients, 228 (41%) had
evidence of enteropathy (Group 1, CD) and 334 (59%) did not (Group 2, NCGS). The most common
neurological manifestations were cerebellar ataxia, peripheral neuropathy, and encephalopathy. There
was a greater proportion of patients with encephalopathy in Group 1 and with a greater proportion
of neuropathy in Group 2. The severity of ataxia did not differ between the two groups. Patients in
Group 1 had more severe neuropathy. All patients from both groups responded to gluten-free diet.
Anti-tissue transglutaminase (TG2) antibodies were found in 91% of patients in Group 1 and in
29% of patients in Group 2. Comparison between those patients in Group 2 with HLA-DQ2/DQ8 and
those without as well as those with positive TG2 compared with those with negative TG2 antibodies
identifi ed no differences within these subgroups. Serological positivity for TG6 antibodies was similar
in the two groups (67 and 60%).
CONCLUSIONS: The neurological manifestations of CD and NCGS are similar and equally responsive to a GFD
suggestive of common pathophysiological mechanisms
Circumstellar interaction in supernovae in dense environments - an observational perspective
In a supernova explosion, the ejecta interacting with the surrounding
circumstellar medium (CSM) give rise to variety of radiation. Since CSM is
created from the mass lost from the progenitor star, it carries footprints of
the late time evolution of the star. This is one of the unique ways to get a
handle on the nature of the progenitor star system. Here, I will focus mainly
on the supernovae (SNe) exploding in dense environments, a.k.a. Type IIn SNe.
Radio and X-ray emission from this class of SNe have revealed important
modifications in their radiation properties, due to the presence of high
density CSM. Forward shock dominance of the X-ray emission, internal free-free
absorption of the radio emission, episodic or non-steady mass loss rate,
asymmetry in the explosion seem to be common properties of this class of SNe.Comment: Fixed minor typos. 31 pages, 9 figures, accepted for publication in
Space Science Reviews. Chapter in International Space Science Institute
(ISSI) Book on "Supernovae" to be published in Space Science Reviews by
Springe
Bedrijfsvoering zit in de weg : Landbouw slechts beperkt inzetbaar voor natuur- en landschapsbehoud
Het rijk wil natuurdoelen realiseren met een grotere inzet van agrariërs. Er is echter veel kritiek op de effectiviteit van agrarisch natuurbeheer. Agrariërs blijken meestal de lichtere pakketten uit de subsidiiregelingen te kiezen, terwijl vooral zware pakketten nodig zijn om de beoogde natuurdoelen te halen. Ook het landschapsbeheer is onvoldoende om het landschap te behouden. Wij constateren dat voor natuur- en landschapsbehoud grote aanpassingen in de bedrijfsvoering nodig zijn waarvoor de subsidieregelingen geen vergoedingen bieden
Neurologic deficits in patients with newly diagnosed celiac disease are frequent and linked with autoimmunity to TG6
Background & Aims
Celiac disease is an autoimmune disorder induced by ingestion of gluten that affects 1% of the population and is characterized by gastrointestinal symptoms, weight loss, and anemia. We evaluated the presence of neurologic deficits and investigated whether the presence of antibodies to TG6 increases the risk of neurologic defects in patients with a new diagnosis of celiac disease.
Methods
We performed a prospective cohort study at a secondary-care gastroenterology center of 100 consecutive patients who received a new diagnosis of celiac disease based on gastroscopy and duodenal biopsy. We collected data on neurologic history, and patients were evaluated in a clinical examination along with magnetic resonance imaging (MRI) of the brain, MR spectroscopy of the cerebellum, and measurements of antibodies against TG6 in serum samples. The first 52 patients recruited underwent repeat MR spectroscopy at 1 year after a gluten-free diet (GFD). The primary aim was to establish if detection of antibodies against TG6 can be used to identify patients with celiac disease and neurologic dysfunction.
Results
Gait instability was reported in 24% of the patients, persisting sensory symptoms in 12%, and frequent headaches in 42%. Gait ataxia was found in 29% of patients, nystagmus in 11%, and distal sensory loss in 10%. Sixty percent of patients had abnormal results from the MRI, 47% had abnormal results from MR spectroscopy of the cerebellum, and 25% had brain white matter lesions beyond that expected for their age group. Antibodies against TG6 were detected in serum samples from 40% of patients–these patients had significant atrophy of subcortical brain regions compared to patients without TG6 autoantibodies. In patients with abnormal results from MR spectroscopy of the cerebellum, those on the GFD had improvements detected in the repeat MR spectroscopy 1 year later.
Conclusions
In a prospective cohort study of patients with a new diagnosis of celiac disease at a gastroenterology clinic, neurological deficits were common and 40% had circulating antibodies against TG6. We observed a significant reduction in volume of specific brain regions in patients with TG6 autoantibodies, providing evidence for a link between autoimmunity to TG6 and brain atrophy in patients with celiac disease. There is a need for early diagnosis, increased awareness of the neurological manifestations amongst clinicians and reinforcement of adherence to a strict GFD by patients in order to avoid permanent neurological disability
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