1,141 research outputs found
A violation of the uncertainty principle implies a violation of the second law of thermodynamics
Uncertainty relations state that there exist certain incompatible
measurements, to which the outcomes cannot be simultaneously predicted. While
the exact incompatibility of quantum measurements dictated by such uncertainty
relations can be inferred from the mathematical formalism of quantum theory,
the question remains whether there is any more fundamental reason for the
uncertainty relations to have this exact form. What, if any, would be the
operational consequences if we were able to go beyond any of these uncertainty
relations? We give a strong argument that justifies uncertainty relations in
quantum theory by showing that violating them implies that it is also possible
to violate the second law of thermodynamics. More precisely, we show that
violating the uncertainty relations in quantum mechanics leads to a
thermodynamic cycle with positive net work gain, which is very unlikely to
exist in nature.Comment: 8 pages, revte
Bell Correlations and the Common Future
Reichenbach's principle states that in a causal structure, correlations of
classical information can stem from a common cause in the common past or a
direct influence from one of the events in correlation to the other. The
difficulty of explaining Bell correlations through a mechanism in that spirit
can be read as questioning either the principle or even its basis: causality.
In the former case, the principle can be replaced by its quantum version,
accepting as a common cause an entangled state, leaving the phenomenon as
mysterious as ever on the classical level (on which, after all, it occurs). If,
more radically, the causal structure is questioned in principle, closed
space-time curves may become possible that, as is argued in the present note,
can give rise to non-local correlations if to-be-correlated pieces of classical
information meet in the common future --- which they need to if the correlation
is to be detected in the first place. The result is a view resembling Brassard
and Raymond-Robichaud's parallel-lives variant of Hermann's and Everett's
relative-state formalism, avoiding "multiple realities."Comment: 8 pages, 5 figure
Colliding Hadrons as Cosmic Membranes and Possible Signatures of Lost Momentum
We argue that in the TeV-gravity scenario high energy hadrons colliding on
the 3-brane embedded in D=4+n-dimensional spacetime, with n dimensions smaller
than the hadron size, can be considered as cosmic membranes. In the
5-dimensional case these cosmic membranes produce effects similar to cosmic
strings in the 4-dimensional world. We calculate the corrections to the eikonal
approximation for the gravitational scattering of partons due to the presence
of effective hadron cosmic membranes. Cosmic membranes dominate the momentum
lost in the longitudinal direction for colliding particles that opens new
channels for particle decays.Comment: 15 pages, Late
Preparation of distilled and purified continuous variable entangled states
The distribution of entangled states of light over long distances is a major
challenge in the field of quantum information. Optical losses, phase diffusion
and mixing with thermal states lead to decoherence and destroy the
non-classical states after some finite transmission-line length. Quantum
repeater protocols, which combine quantum memory, entanglement distillation and
entanglement swapping, were proposed to overcome this problem. Here we report
on the experimental demonstration of entanglement distillation in the
continuous-variable regime. Entangled states were first disturbed by random
phase fluctuations and then distilled and purified using interference on beam
splitters and homodyne detection. Measurements of covariance matrices clearly
indicate a regained strength of entanglement and purity of the distilled
states. In contrast to previous demonstrations of entanglement distillation in
the complementary discrete-variable regime, our scheme achieved the actual
preparation of the distilled states, which might therefore be used to improve
the quality of downstream applications such as quantum teleportation
Annotation of two large contiguous regions from the Haemonchus contortus genome using RNA-seq and comparative analysis with Caenorhabditis elegans
The genomes of numerous parasitic nematodes are currently being sequenced, but their complexity and size, together with high levels of intra-specific sequence variation and a lack of reference genomes, makes their assembly and annotation a challenging task. Haemonchus contortus is an economically significant parasite of livestock that is widely used for basic research as well as for vaccine development and drug discovery. It is one of many medically and economically important parasites within the strongylid nematode group. This group of parasites has the closest phylogenetic relationship with the model organism Caenorhabditis elegans, making comparative analysis a potentially powerful tool for genome annotation and functional studies. To investigate this hypothesis, we sequenced two contiguous fragments from the H. contortus genome and undertook detailed annotation and comparative analysis with C. elegans. The adult H. contortus transcriptome was sequenced using an Illumina platform and RNA-seq was used to annotate a 409 kb overlapping BAC tiling path relating to the X chromosome and a 181 kb BAC insert relating to chromosome I. In total, 40 genes and 12 putative transposable elements were identified. 97.5% of the annotated genes had detectable homologues in C. elegans of which 60% had putative orthologues, significantly higher than previous analyses based on EST analysis. Gene density appears to be less in H. contortus than in C. elegans, with annotated H. contortus genes being an average of two-to-three times larger than their putative C. elegans orthologues due to a greater intron number and size. Synteny appears high but gene order is generally poorly conserved, although areas of conserved microsynteny are apparent. C. elegans operons appear to be partially conserved in H. contortus. Our findings suggest that a combination of RNA-seq and comparative analysis with C. elegans is a powerful approach for the annotation and analysis of strongylid nematode genomes
Intraoperative radiotherapy (IORT) is an option for patients with localized breast recurrences after previous external-beam radiotherapy
<p>Abstract</p> <p>Background</p> <p>For patients suffering of recurrent breast cancer within the irradiated breast, generally mastectomy is recommended. The normal tissue tolerance does not permit a second full-dose course of radiotherapy to the entire breast after a second breast-conserving surgery (BCS). A novel option is to treat these patients with partial breast irradiation (PBI). This approach is based on the hypothesis that re-irradiation of a limited volume will be effective and result in an acceptable frequency of side effects. The following report presents a single center experience with intraoperative radiotherapy (IORT) during excision of recurrent breast cancer in the previously irradiated breast.</p> <p>Methods</p> <p>Between 4/02 and 11/06, 15 patients were treated for in-breast recurrences at a median of 10 years (3â25) after previous EBRT (10 recurrences in the initial tumor bed, 3 elsewhere in-breast failures, 2 invasive recurrences after previous DCIS). Additional 2 patients were selected for IORT with new primary breast cancer after previous partial breast EBRT for treatment of Hodgkin's disease. IORT with a single dose of 14.7 â 20 Gy 50 kV X-rays at the applicator surface was delivered with the Intrabeamâą-device (Carl Zeiss, Oberkochen, Germany).</p> <p>Results</p> <p>After a median follow-up of 26 months (1â60), no local recurrence occurred. 14 out of 17 patients are alive and free of disease progression. Two patients are alive with distant metastases. One patient died 26 months after BCS/IORT due to pulmonary metastases diagnosed 19 months after BCS/IORT. Acute toxicity after IORT was mild with no Grade 3/4 toxicities and cosmetic outcome showed excellent/good/fair results in 7/7/3 cases.</p> <p>Conclusion</p> <p>IORT for recurrent breast cancer using low energy X-rays is a valuable option for patients with recurrent breast cancer after previous radiotherapy.</p
RPPAML/RIMS: A metadata format and an information management system for reverse phase protein arrays
<p>Abstract</p> <p>Background</p> <p>Reverse Phase Protein Arrays (RPPA) are convenient assay platforms to investigate the presence of biomarkers in tissue lysates. As with other high-throughput technologies, substantial amounts of analytical data are generated. Over 1000 samples may be printed on a single nitrocellulose slide. Up to 100 different proteins may be assessed using immunoperoxidase or immunoflorescence techniques in order to determine relative amounts of protein expression in the samples of interest.</p> <p>Results</p> <p>In this report an RPPA Information Management System (RIMS) is described and made available with open source software. In order to implement the proposed system, we propose a metadata format known as reverse phase protein array markup language (RPPAML). RPPAML would enable researchers to describe, document and disseminate RPPA data. The complexity of the data structure needed to describe the results and the graphic tools necessary to visualize them require a software deployment distributed between a client and a server application. This was achieved without sacrificing interoperability between individual deployments through the use of an open source semantic database, S3DB. This data service backbone is available to multiple client side applications that can also access other server side deployments. The RIMS platform was designed to interoperate with other data analysis and data visualization tools such as Cytoscape.</p> <p>Conclusion</p> <p>The proposed RPPAML data format hopes to standardize RPPA data. Standardization of data would result in diverse client applications being able to operate on the same set of data. Additionally, having data in a standard format would enable data dissemination and data analysis.</p
Entropic Uncertainty Relations in Quantum Physics
Uncertainty relations have become the trademark of quantum theory since they
were formulated by Bohr and Heisenberg. This review covers various
generalizations and extensions of the uncertainty relations in quantum theory
that involve the R\'enyi and the Shannon entropies. The advantages of these
entropic uncertainty relations are pointed out and their more direct connection
to the observed phenomena is emphasized. Several remaining open problems are
mentionedComment: 35 pages, review pape
Impact of movement training on upper limb motor strategies in persons with shoulder impingement syndrome
<p>Abstract</p> <p>Background</p> <p>Movement deficits, such as changes in the magnitude of scapulohumeral and scapulathoracic muscle activations or perturbations in the kinematics of the glenohumeral, sternoclavicular and scapulothoracic joints, have been observed in people with shoulder impingement syndrome. Movement training has been suggested as a mean to contribute to the improvement of the motor performance in persons with musculoskeletal impairments. However, the impact of movement training on the movement deficits of persons with shoulder impingement syndrome is still unknown. The aim of this study was to evaluate the short-term effects of supervised movement training with feedback on the motor strategies of persons with shoulder impingement syndrome.</p> <p>Methods</p> <p>Thirty-three subjects with shoulder impingement were recruited. They were involved in two visits, one day apart. During the first visit, supervised movement training with feedback was performed. The upper limb motor strategies were evaluated before, during, immediately after and 24 hours after movement training. They were characterized during reaching movements in the frontal plane by EMG activity of seven shoulder muscles and total excursion and final position of the wrist, elbow, shoulder, clavicle and trunk. Movement training consisted of reaching movements performed under the supervision of a physiotherapist who gave feedback aimed at restoring shoulder movements. One-way repeated measures ANOVAs were run to analyze the effect of movement training.</p> <p>Results</p> <p>During, immediately after and 24 hours after movement training with feedback, the EMG activity was significantly decreased compared to the baseline level. For the kinematics, total joint excursion of the trunk and final joint position of the trunk, shoulder and clavicle were significantly improved during and immediately after training compared to baseline. Twenty-four hours after supervised movement training, the kinematics of trunk, shoulder and clavicle were back to the baseline level.</p> <p>Conclusion</p> <p>Movement training with feedback brought changes in motor strategies and improved temporarily some aspects of the kinematics. However, one training session was not enough to bring permanent improvement in the kinematic patterns. These results demonstrate the potential of movement training in the rehabilitation of movement deficits associated with shoulder impingement syndrome.</p
The Drosophila melanogaster PeptideAtlas facilitates the use of peptide data for improved fly proteomics and genome annotation
<p>Abstract</p> <p>Background</p> <p>Crucial foundations of any quantitative systems biology experiment are correct genome and proteome annotations. Protein databases compiled from high quality empirical protein identifications that are in turn based on correct gene models increase the correctness, sensitivity, and quantitative accuracy of systems biology genome-scale experiments.</p> <p>Results</p> <p>In this manuscript, we present the <it>Drosophila melanogaster </it>PeptideAtlas, a fly proteomics and genomics resource of unsurpassed depth. Based on peptide mass spectrometry data collected in our laboratory the portal <url>http://www.drosophila-peptideatlas.org</url> allows querying fly protein data observed with respect to gene model confirmation and splice site verification as well as for the identification of proteotypic peptides suited for targeted proteomics studies. Additionally, the database provides consensus mass spectra for observed peptides along with qualitative and quantitative information about the number of observations of a particular peptide and the sample(s) in which it was observed.</p> <p>Conclusion</p> <p>PeptideAtlas is an open access database for the <it>Drosophila </it>community that has several features and applications that support (1) reduction of the complexity inherently associated with performing targeted proteomic studies, (2) designing and accelerating shotgun proteomics experiments, (3) confirming or questioning gene models, and (4) adjusting gene models such that they are in line with observed <it>Drosophila </it>peptides. While the database consists of proteomic data it is not required that the user is a proteomics expert.</p
- âŠ