2,920 research outputs found
Two-batch liar games on a general bounded channel
We consider an extension of the 2-person R\'enyi-Ulam liar game in which lies
are governed by a channel , a set of allowable lie strings of maximum length
. Carole selects , and Paul makes -ary queries to uniquely
determine . In each of rounds, Paul weakly partitions and asks for such that . Carole responds with some
, and if , then accumulates a lie . Carole's string of
lies for must be in the channel . Paul wins if he determines within
rounds. We further restrict Paul to ask his questions in two off-line
batches. We show that for a range of sizes of the second batch, the maximum
size of the search space for which Paul can guarantee finding the
distinguished element is as ,
where is the number of lie strings in of maximum length . This
generalizes previous work of Dumitriu and Spencer, and of Ahlswede, Cicalese,
and Deppe. We extend Paul's strategy to solve also the pathological liar
variant, in a unified manner which gives the existence of asymptotically
perfect two-batch adaptive codes for the channel .Comment: 26 page
Oxygen vacancy segregation and space-charge effects in grain boundaries of dry and hydrated BaZrO3
A space-charge model is applied to describe the equilibrium effects of
segregation of double-donor oxygen vacancies to grain boundaries in dry and wet
acceptor-doped samples of the perovskite oxide BaZrO3. The grain boundary core
vacancy concentrations and electrostatic potential barriers resulting from
different vacancy segregation energies are evaluated. Density-functional
calculations on vacancy segregation to the mirror-symmetric \Sigma 3 (112)
[-110] tilt grain boundary are also presented. Our results indicate that oxygen
vacancy segregation can be responsible for the low grain boundary proton
conductivity in BaZrO3 reported in the literature
Variants of the human PPARG locus and the susceptibility to chronic periodontitis
Apart from its regulatory function in lipid and glucose metabolism, peroxisome proliferator-activated receptor (PPAR)γ has impact on the regulation of inflammation and bone metabolism. The aim of the study was to investigate the association of five polymorphisms (rs10865710, rs2067819, rs3892175, rs1801282, rs3856806) within the PPARG gene with chronic periodontitis. The study population comprised 402 periodontitis patients and 793 healthy individuals. Genotyping of the PPARG gene polymorphisms was performed by PCR and melting curve analysis. Comparison of frequency distribution of genotypes between individuals with periodontal disease and healthy controls for the polymorphism rs3856806 showed a P-value of 0.04 but failed to reach significance after correction for multiple testing (P  0.90). A 3-site analysis (rs2067819-rs1801282-rs3856860) revealed five haplotypes with a frequency of ≥1% among cases and controls. Following adjustment for age, gender and smoking, none of the haplotypes was significantly different between periodontitis and healthy controls after Bonferroni correction. This study could not show a significant association between PPARG gene variants and chronic periodontitis
The evolutionary state of the southern dense core Cha-MMS1
Aims: Our goal is to set constraints on the evolutionary state of the dense
core Cha-MMS1 in the Chamaeleon I molecular cloud. Methods: We analyze
molecular line observations carried out with the new submillimeter telescope
APEX. We look for outflow signatures around the dense core and probe its
chemical structure, which we compare to predictions of models of gas-phase
chemistry. We also use the public database of the Spitzer Space Telescope (SST)
to compare Cha-MMS1 with the two Class 0 protostars IRAM 04191 and L1521F,
which are at the same distance. Results: We measure a large deuterium
fractionation for N2H+ (11 +/- 3 %), intermediate between the prestellar core
L1544 and the very young Class 0 protostar L1521F. It is larger than for HCO+
(2.5 +/- 0.9 %), which is probably the result of depletion removing HCO+ from
the high-density inner region. Our CO(3-2) map reveals the presence of a
bipolar outflow driven by the Class I protostar Ced 110 IRS 4 but we do not
find evidence for an outflow powered by Cha-MMS1. We also report the detection
of Cha-MMS1 at 24, 70 and 160 microns by the instrument MIPS of the SST, at a
level nearly an order of magnitude lower than IRAM 04191 and L1521F.
Conclusions: Cha-MMS1 appears to have already formed a compact object, either
the first hydrostatic core at the very end of the prestellar phase, or an
extremely young protostar that has not yet powered any outflow, at the very
beginning of the Class 0 accretion phase.Comment: Accepted by Astronomy & Astrophysics as a letter, to appear in the
special issue on the APEX first result
Tapered-amplified AR-coated laser diodes for Potassium and Rubidium atomic-physics experiments
We present a system of room-temperature extended-cavity grating-diode lasers
(ECDL) for production of light in the range 760-790nm. The extension of the
tuning range towards the blue is permitted by the weak feedback in the cavity:
the diodes are anti-reflection coated, and the grating has just 10%
reflectance. The light is then amplified using semiconductor tapered amplifiers
to give more than 400mW of power. The outputs are shown to be suitable for
atomic physics experiments with potassium (767nm), rubidium (780nm) or both, of
particular relevance to doubly-degenerate boson-fermion mixtures
REXEBIS the Electron Beam Ion Source for the REX-ISOLDE project
The REXEBIS is an Electron Beam Ion Source (EBIS) developed especially to trap and further ionise the sometimes rare and short-lived isotopes that are produced in the ISOLDE separator for the Radioactive beam EXperiment at ISOLDE (REX-ISOLDE). By promoting the single-charged ions to a high charge-state the ions are more efficiently accelerated in the following linear accelerator. The EBIS uses an electron gun capable of producing a 0.5 A electron beam. The electron gun is immersed in a magnetic field of 0.2 T, and the electron beam is compressed to a current density of >200 A/cm2 inside a 2 T superconducting solenoid. The EBIS is situated on a high voltage (HV) platform with an initial electric potential of 60 kV allowing cooled and bunched 60 keV ions extracted from a Penning trap to be captured. After a period of confinement in the electron beam (<20 ms), the single-charged ions have been ionised to a charge-to-mass ratio of approximately ¼. During this confinement period, the platform potential is decreased to about 20 kV, and an axial potential barrier is lowered to allow the now highly charged ions to be extracted from the EBIS at an energy matching the requirement of the Radio Frequency Quadrupole (RFQ). Several different topics are presented in this report, all connected with the design and construction of an EBIS. Old 'truths' have also been scrutinised, for instance alignment tolerances. A large part is devoted to the description of a novel EBIS simulation implementation. A complete injection, breeding and extraction cycle has been simulated to certify high injection and extraction efficiencies. The entire EBIS was modelled in an ion-tracing program called SIMION, and the accepted and emitted phase spaces were determined. Beam optics parameters such as lens positions, voltages, accepted beam-tilt and displacement tolerances at the focal points were also settled using SIMION. An analytically derived acceptance formula was verified with simulations, and general conclusions on acceptance, emittance and energy spread of an EBIS are presented in this report. Any possible correlation between the two transverse phase spaces was shown to be insignificant. Furthermore, continuous injection, and maximal obtainable efficiency for such an injection mode were studied theoretically. The electron reflection and back-scattering in the collector was simulated using a combination of EGUN and SIMION. The result showed that a much lower degree of electron back-scattering may be obtained with this design as compared to previously published estimations. Furthermore, the Penning trapping of electrons at the trap barrier (or the post anode) was addressed, and techniques to avoid it were evaluated. Vacuum considerations for residual gas in the warm-bore magnet chamber, and the back-flow of Ar cooling gas from the Penning trap, have also been addressed since there is a risk of outnumbering the small number of radioactive ions. Simulated extraction spectra for different pressure scenarios are presented. All different REXEBIS elements (magnet, electron gun, inner structure, collector etc) are described from a design and performance perspective, and preliminary investigations of the platform high voltage switching and the beam diagnostics are included as well. A very elegant and simple method to align the solenoid within the iron yoke was developed and used. The high experimental emittance value obtained for electron beam ion source at MSL in Stockholm (4 times larger than the absolute upper theoretical value) was reproduced in simulations and could be justified by aberrations in the small einzel lens following the collector. The result of this simulation also verified the validity of the developed EBIS code
Mass spectrometry-based proteomic exploration of the human immune system : focus on the inflammasome, global protein secretion, and T cells
Introduction: The immune system is our defense system against microbial infections and tissue injury, and understanding how it works in detail is essential for developing drugs for different diseases. Mass spectrometry-based proteomics can provide in-depth information on the molecular mechanisms involved in immune responses.Areas covered: Summarized are the key immunology findings obtained with MS-based proteomics in the past five years, with a focus on inflammasome activation, global protein secretion, mucosal immunology, immunopeptidome and T cells. Special focus is on extracellular vesicle-mediated protein secretion and its role in immune responses.Expert commentary: Proteomics is an essential part of modern omics-scale immunology research. To date, MS-based proteomics has been used in immunology to study protein expression levels, their subcellular localization, secretion, post-translational modifications, and interactions in immune cells upon activation by different stimuli. These studies have made major contributions to understanding the molecular mechanisms involved in innate and adaptive immune responses. New developments in proteomics offer constantly novel possibilities for exploring the immune system. Examples of these techniques include mass cytometry and different MS-based imaging approaches which can be widely used in immunology.Peer reviewe
Physical properties of Southern infrared dark clouds
It is commonly assumed that cold and dense Infrared Dark Clouds (IRDCs)
likely represent the birth sites massive stars. Therefore, this class of
objects gets increasing attention. To enlarge the sample of well-characterised
IRDCs in the southern hemisphere, we have set up a program to study the gas and
dust of southern IRDCs. The present paper aims at characterizing the continuuum
properties of this sample of objects. We cross-correlated 1.2 mm continuum data
from SIMBA@SEST with Spitzer/GLIMPSE images to establish the connection between
emission sources at millimeter wavelengths and the IRDCs we see at 8 m in
absorption against the bright PAH background. Analysing the dust emission and
extinction leads to a determination of masses and column densities, which are
important quantities in characterizing the initial conditions of massive star
formation. The total masses of the IRDCs were found to range from 150 to 1150
(emission data) and from 300 to 1750 (extinction
data). We derived peak column densities between 0.9 and 4.6
cm (emission data) and 2.1 and 5.4 cm
(extinction data). We demonstrate that the extinction method fails for very
high extinction values (and column densities) beyond A values of
roughly 75 mag according to the Weingartner & Draine (2001) extinction relation
model B. The derived column densities, taking into account
the spatial resolution effects, are beyond the column density threshold of 3.0
cm required by theoretical considerations for massive
star formation. We conclude that the values for column densities derived for
the selected IRDC sample make these objects excellent candidates for objects in
the earliest stages of massive star formation.Comment: Accepted for publication in Astronomy & Astrophysic
Massachusetts Adult Tobacco Survey: Tobacco Use and Attitudes After Seven Years of The Massachusetts Tobacco Control Program, Technical Report & Tables 1993 — 2000
The Massachusetts Tobacco Control Program was launched in October of 1993. At that time, the Center for Survey Research conducted the Massachusetts Tobacco Survey (MTS), a comprehensive survey of adults and teens living in Massachusetts. The purpose of the survey was to collect baseline data on the prevalence of tobacco use among adults and teens in the Commonwealth and on issues related to the likelihood of smoking cessation or initiation. The survey also assessed the prevalence of restrictive smoking policies, and attitudes about tobacco control measures. The baseline data serve as a standard against which the impact of various programs sponsored by the Department of Public Health can be assessed. Technical details about the MTS and reports of the results are available from the Massachusetts Department of Public Health.
In January, 1995 the Department of Public Health contracted with the Center for Survey Research to carry out a second survey monitoring tobacco use and related attitudes and behaviors among adults in the Commonwealth. This second survey, known as the Massachusetts Adult Tobacco Survey (MATS), has been carried out monthly since March of 1995. Data are aggregated at the end of each calendar year. MATS is similar to the MTS in that initial screening interviews are carried out with a household member who provides demographic and smoking status information about other adults in the household. One member of the household is then randomly selected for extended interview. The annual sample for this survey is smaller than that used for the MTS and does not include teens. It also differs from the MTS in that smokers were not over-sampled, nor were members of minority groups. The sample was geographically stratified as was the MTS. (More details on the sampling design are presented in Chapter I.)
Technical Reports are available for the 1993 MTS survey, and for the 1995 through 1999 MATS surveys. Please refer to those reports for descriptions of the respective surveys and a more general discussion of the use of the telephone survey for data collection. This report presents methodological details of the 2000 MATS. It contains an appendix of tables of major results for data collected each year. Nontechnical reports describing the major results are available from the Massachusetts Department of Public Health
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