2,037 research outputs found
Development of conformal coating materials
New polymeric compositions appear useful as coatings on electronic circuitry operating in rigorous environments. Formulation of their compositions is based on nitrosofluorocarbon polymers having active cure sites
High-fidelity state detection and tomography of a single ion Zeeman qubit
We demonstrate high-fidelity Zeeman qubit state detection in a single trapped
88 Sr+ ion. Qubit readout is performed by shelving one of the qubit states to a
metastable level using a narrow linewidth diode laser at 674 nm followed by
state-selective fluorescence detection. The average fidelity reached for the
readout of the qubit state is 0.9989(1). We then measure the fidelity of state
tomography, averaged over all possible single-qubit states, which is 0.9979(2).
We also fully characterize the detection process using quantum process
tomography. This readout fidelity is compatible with recent estimates of the
detection error-threshold required for fault-tolerant computation, whereas
high-fidelity state tomography opens the way for high-precision quantum process
tomography
The Labour Market Value of Liberal Arts and Applied Education Programs: Evidence from British Columbia
In this article, labour market outcomes of British Columbia graduates from liberal arts and applied education programs are investigated by examining the 1996 cohort of baccalaureate graduates one year and five years after graduation. We argue that the individual return to education has to be analyzed from a multi-dimensional perspective, in relation to initial educational and career goals of graduates who have anticipated both intellectual challenges and economic rewards from their investment in education. The study reveals differences in outcomes (i.e., employment, earnings) by program type, gender and age. Our main conclusion is that graduates from applied education programs experience a more rapid integration into the labour market as compared to graduates from liberal arts education programs. Although earning differences by program type and age either decrease or even disappear over time, earning differences by gender are enhanced five years after graduation. Also, we conclude that graduates from applied education programs establish and accomplish more focused educational and career goals, while graduates from liberal education programs establish broader educational and career goals.On examinera les débouchés sur le marché de travail qui s’ouvrent aux jeunes issus des études post-secondaires professionnelles ou généralistes, à l’aide des données sur la cohorte de bacheliers de 1996, obtenues un an et cinq après la fi n de leurs études. Nous affirmons que le retour individuel vers l’éducation doit être examiné dans une perspective multidimensionnelle, en rapport avec les buts éducationnels et la carrière des bacheliers, qui ont anticipé à la fois des diffi cultés intellectuelles et des récompenses financières de leur investissement dans le processus d’éducation. L’analyse montre des différences au niveau des débouchés (par exemple emploi, salaire), en fonction du type de programme scolaire suivi, de l’âge et du sexe. Notre conclusion principale est que les jeunes qui ont poursuivi des études professionnelles s’adaptent plus rapidement aux demandes du marché du travail que ceux issus des études généralistes. Alors que la relation de dépendance entre les différences de salaire et le type d’étude ou l’âge diminue, voire disparaît avec le temps, la relation de dépendance entre différences des salaires et sexe augmente cinq ans après la fin des études. On conclut aussi que les jeunes ayant poursuivi des études professionnelles envisagent et réalisent des buts éducationnels et de carrière plus précis, alors que ceux qui ont fini des études généralistes envisagent des buts éducationnels et de carrière plus larges
Delayed protection by ESAT-6–specific effector CD4+ T cells after airborne M. tuberculosis infection
Mycobacterium tuberculosis infection induces complex CD4 T cell responses that include T helper type 1 (Th1) cells and regulatory T cells. Although Th1 cells control infection, they are unable to fully eliminate M. tuberculosis, suggesting that Th1-mediated immunity is restrained from its full sterilizing potential. Investigation into T cell–mediated defense is hindered by difficulties in expanding M. tuberculosis–specific T cells. To circumvent this problem, we cloned CD4+ T cells from M. tuberculosis–infected B6 mice and generated transgenic mice expressing a T cell receptor specific for the immunodominant antigen early secreted antigenic target 6 (ESAT-6). Adoptively transferred naive ESAT-6–specific CD4+ T cells are activated in pulmonary lymph nodes between 7 and 10 d after aerosol infection and undergo robust expansion before trafficking to the lung. Adoptive transfer of activated ESAT-6–specific Th1 cells into naive recipients before aerosol M. tuberculosis infection dramatically enhances resistance, resulting in 100-fold fewer bacteria in infected lungs. However, despite large numbers of Th1 cells in the lungs of mice at the time of M. tuberculosis challenge, protection was not manifested until after 7 d following infection. Our results demonstrate that pathogen-specific Th1 cells can provide protection against inhaled M. tuberculosis, but only after the first week of infection
How to Choose a Champion
League competition is investigated using random processes and scaling
techniques. In our model, a weak team can upset a strong team with a fixed
probability. Teams play an equal number of head-to-head matches and the team
with the largest number of wins is declared to be the champion. The total
number of games needed for the best team to win the championship with high
certainty, T, grows as the cube of the number of teams, N, i.e., T ~ N^3. This
number can be substantially reduced using preliminary rounds where teams play a
small number of games and subsequently, only the top teams advance to the next
round. When there are k rounds, the total number of games needed for the best
team to emerge as champion, T_k, scales as follows, T_k ~N^(\gamma_k) with
gamma_k=1/[1-(2/3)^(k+1)]. For example, gamma_k=9/5,27/19,81/65 for k=1,2,3.
These results suggest an algorithm for how to infer the best team using a
schedule that is linear in N. We conclude that league format is an ineffective
method of determining the best team, and that sequential elimination from the
bottom up is fair and efficient.Comment: 6 pages, 3 figure
Lung sound amplitude measured by vibration response imaging is influenced by the presence of secretions
Are Patients With Longer Emergency Department Wait Times Less Likely to Consent to Research?
Objectives: There are unique challenges to enrolling patients in emergency department (ED) clinical
research studies, including the time-sensitive nature of emergency conditions, the acute care environ-
ment, and the lack of an established relationship with patients. Prolonged ED wait times have been asso-
ciated with a variety of adverse effects on patient care. The objective of this study was to assess the
effect of ED wait times on patient participation in ED clinical research. The hypothesis was that
increased ED wait times would be associated with reduced ED clinical research consent rates.
Methods: This was a retrospective cohort study of all patients eligible for two diagnostic clinical research
studies from January 1, 2008, through December 31, 2008, in an urban academic ED. Sex, age, race, study
eligibility, and research consent decisions were recorded by trained study personnel. The wait times to
registration and to be seen by a physician were obtained from administrative databases and compared
between consenters and nonconsenters. An analysis of association between patient wait times for the
outcome of consent to participate was performed using a multivariate logistic regression model.
Results: A total of 903 patients were eligible for enrollment and were asked for consent. Overall, 589
eligible patients (65%) gave consent to research participation. The consent rates did not change when
patients were stratified by the highest and lowest quartile wait times for both time from arrival to regis-
tration (68% vs. 65%, p = 0.35) and time to be seen by a physician (65% vs. 66%, p = 0.58). After adjusting
for patient demographics (age, race, and sex) and study, there was still no relationship between wait
times and consent (p > 0.4 for both wait times). Furthermore, median time from arrival to registration did
not differ between those who consented to participate (15 minutes; interquartile range [IQR] = 9 to
36 minutes) versus those who did not (15.5 minutes; IQR = 10 to 39 minutes; p = 0.80; odds ratio
[OR] = 1.00, 95% confidence interval [CI] = 0.99 to 1.01). Similarly, there was no difference in the median
time to be seen by a physician between those who consented (25 minutes; IQR = 15 to 55 minutes) versus
those who did not (25 minutes; IQR = 15 to 56 minutes; p = 0.70; OR = 1.00, 95% CI = 0.99 to 1.01).
Conclusions: Regardless of wait times, nearly two-thirds of eligible patients were willing to consent to
diagnostic research studies in the ED. These findings suggest that effective enrollment in clinical
research is possible in the ED, despite challenges with prolonged wait times
Interaction of CarD with RNA polymerase mediates Mycobacterium tuberculosis viability, rifampin resistance, and pathogenesis
Mycobacterium tuberculosis infection continues to cause substantial human suffering. New chemotherapeutic strategies, which require insight into the pathways essential for M. tuberculosis pathogenesis, are imperative. We previously reported that depletion of the CarD protein in mycobacteria compromises viability, resistance to oxidative stress and fluoroquinolones, and pathogenesis. CarD associates with the RNA polymerase (RNAP), but it has been unknown which of the diverse functions of CarD are mediated through the RNAP; this question must be answered to understand the CarD mechanism of action. Herein, we describe the interaction between the M. tuberculosis CarD and the RNAP β subunit and identify point mutations that weaken this interaction. The characterization of mycobacterial strains with attenuated CarD/RNAP β interactions demonstrates that the CarD/RNAP β association is required for viability and resistance to oxidative stress but not for fluoroquinolone resistance. Weakening the CarD/RNAP β interaction also increases the sensitivity of mycobacteria to rifampin and streptomycin. Surprisingly, depletion of the CarD protein did not affect sensitivity to rifampin. These findings define the CarD/RNAP interaction as a new target for chemotherapeutic intervention that could also improve the efficacy of rifampin treatment of tuberculosis. In addition, our data demonstrate that weakening the CarD/RNAP β interaction does not completely phenocopy the depletion of CarD and support the existence of functions for CarD independent of direct RNAP binding
Converting genetic network oscillations into somite spatial pattern
In most vertebrate species, the body axis is generated by the formation of
repeated transient structures called somites. This spatial periodicity in
somitogenesis has been related to the temporally sustained oscillations in
certain mRNAs and their associated gene products in the cells forming the
presomatic mesoderm. The mechanism underlying these oscillations have been
identified as due to the delays involved in the synthesis of mRNA and
translation into protein molecules [J. Lewis, Current Biol. {\bf 13}, 1398
(2003)]. In addition, in the zebrafish embryo intercellular Notch signalling
couples these oscillators and a longitudinal positional information signal in
the form of an Fgf8 gradient exists that could be used to transform these
coupled temporal oscillations into the observed spatial periodicity of somites.
Here we consider a simple model based on this known biology and study its
consequences for somitogenesis. Comparison is made with the known properties of
somite formation in the zebrafish embryo . We also study the effects of
localized Fgf8 perturbations on somite patterning.Comment: 7 pages, 7 figure
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