1,677 research outputs found
The cost and risk impacts of rerouting railroad shipments of hazardous materials
Cataloged from PDF version of article.Rail shipments of hazardous materials expose the population near the routes to the possibility of an accident resulting in a spill. Rail routes are
determined by economic concerns such as route length and the revenue generated for the originating carrier. In this paper we consider an alternate
routing strategy that takes accident risks into account. We employ a model to quantify rail transport risk and then use a weighted combination of
cost and risk and generate alternate routes. In some cases the alternate routes achieve significantly lower risk values than the practical routes at a
small incremental cost. While there are generally fewer rerouting alternatives for rail than for road transport, considering the possible consequences
of a train derailment we argue that risk should be taken into account when selecting rail routes and that the cost–risk tradeoffs should be evaluated.
© 2007 Elsevier Ltd. All rights reserved
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
Proteasome Lid Bridges Mitochondrial Stress with Cdc53/Cullin1 NEDDylation Status
Cycles of Cdc53/Cullin1 rubylation (a.k.a NEDDylation) protect ubiquitin-E3 SCF (Skp1-Cullin1-F-box protein) complexes from self-destruction and play an important role in mediating the ubiquitination of key protein substrates involved in cell cycle progression, development, and survival. Cul1 rubylation is balanced by the COP9 signalosome (CSN), a multi-subunit derubylase that shows 1:1 paralogy to the 26 S proteasome lid. The turnover of SCF substrates and their relevance to various diseases is well studied, yet, the extent by which environmental perturbations influence Cul1 rubylation/derubylation cycles per se is still unclear. In this study, we show that the level of cellular oxidation serves as a molecular switch, determining Cullin1 rubylation/derubylation ratio. We describe a mutant of the proteasome lid subunit, Rpn11 that exhibits accumulated levels of Cullin1-Rub1 conjugates, a characteristic phenotype of csn mutants. By dissecting between distinct phenotypes of rpn11 mutants, proteasome and mitochondria dysfunction, we were able to recognize the high reactive oxygen species (ROS) production during the transition of cells into mitochondrial respiration, as a checkpoint of Cullin1 rubylation in a reversible manner. Thus, the study adds the rubylation cascade to the list of cellular pathways regulated by redox homeostasis
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
Supporting Recovery in the Deaf Community: Creating Continuum of Behavioral Health Care in Central Massachusetts
Across the U.S., there is a paucity of mental health and substance abuse services for Deaf individuals. Without the availability of communication accommodations and specialized clinical expertise, Deaf individuals seeking behavioral health services contend with access limitations, misdiagnoses, and superficial treatments. Moreover, while the assessment and treatment of co-occurring disorders and the infusion of trauma-informed care are key components of effective treatment in the mainstream literature, the investigation and application of these initiatives to the Deaf population has not yet occurred. The proposed poster will outline the current state of specialized behavioral health services for Deaf individuals in Central Massachusetts, identify gaps in the continuum of behavioral health care for this population, and offer recommendations for future behavioral health programming.
Currently, Central Massachusetts is home to two specialized programs for Deaf individuals seeking behavioral health services, the Center for Living and Working’s Deaf Independent Living Services and the DMH Inpatient Deaf Services at Worcester State Recovery Center and Hospital. Unfortunately, even with these programs, it is challenging to find appropriate outpatient placement and services that meet the range of psychiatric, intellectual, linguistic, and cultural needs of Deaf individuals. Connections between inpatient units and specialized outpatient services for the Deaf need to be developed or enhanced to increase continuity of care and reduce rehospitalization of Deaf individuals.
At the current time, specialized outpatient psychotherapy and psychiatry services for Deaf individuals are not available in this region. Lack of funding for AA/NA interpreters and the recent closure of a Deaf-accessible substance abuse treatment agency highlight the need for the development of programs that provide accessible substance abuse treatment. Culturally-affirmative, linguistically-accessible, trauma-informed outpatient behavioral health services that are tailored to the Deaf population are vital to promoting the wellness and recovery of the Deaf community
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
Fission yeast 26S proteasome mutants are multi-drug resistant due to stabilization of the pap1 transcription factor
Here we report the result of a genetic screen for mutants resistant to the microtubule poison methyl benzimidazol-2-yl carbamate (MBC) that were also temperature sensitive for growth. In total the isolated mutants were distributed in ten complementation groups. Cloning experiments revealed that most of the mutants were in essential genes encoding various 26S proteasome subunits. We found that the proteasome mutants are multi-drug resistant due to stabilization of the stress-activated transcription factor Pap1. We show that the ubiquitylation and ultimately the degradation of Pap1 depend on the Rhp6/Ubc2 E2 ubiquitin conjugating enzyme and the Ubr1 E3 ubiquitin-protein ligase. Accordingly, mutants lacking Rhp6 or Ubr1 display drug-resistant phenotypes
Capacity of deep‐sea corals to obtain nutrition from cold seeps aligned with microbiome reorganization
Cold seeps in the deep sea harbor various animals that have adapted to utilize seepage chemicals with the aid of chemosynthetic microbes that serve as primary producers. Corals are among the animals that live near seep habitats and yet, there is a lack of evidence that corals gain benefits and/or incur costs from cold seeps. Here, we focused on Callogorgia delta and Paramuricea sp. type B3 that live near and far from visual signs of currently active seepage at five sites in the deep Gulf of Mexico. We tested whether these corals rely on chemosynthetically-derived food in seep habitats and how the proximity to cold seeps may influence; (i) coral colony traits (i.e., health status, growth rate, regrowth after sampling, and branch loss) and associated epifauna, (ii) associated microbiome, and (iii) host transcriptomes. Stable isotope data showed that many coral colonies utilized chemosynthetically derived food, but the feeding strategy differed by coral species. The microbiome composition of C. delta, unlike Paramuricea sp., varied significantly between seep and non-seep colonies and both coral species were associated with various sulfur-oxidizing bacteria (SUP05). Interestingly, the relative abundances of SUP05 varied among seep and non-seep colonies and were strongly correlated with carbon and nitrogen stable isotope values. In contrast, the proximity to cold seeps did not have a measurable effect on gene expression, colony traits, or associated epifauna in coral species. Our work provides the first evidence that some corals may gain benefits from living near cold seeps with apparently limited costs to the colonies. Cold seeps provide not only hard substrate but also food to cold-water corals. Furthermore, restructuring of the microbiome communities (particularly SUP05) is likely the key adaptive process to aid corals in utilizing seepage-derived carbon. This highlights that those deep-sea corals may upregulate particular microbial symbiont communities to cope with environmental gradients
Quasielastic 12C(e,e'p) Reaction at High Momentum Transfer
We measured the 12C(e,e'p) cross section as a function of missing energy in
parallel kinematics for (q,w) = (970 MeV/c, 330 MeV) and (990 MeV/c, 475 MeV).
At w=475 MeV, at the maximum of the quasielastic peak, there is a large
continuum (E_m > 50 MeV) cross section extending out to the deepest missing
energy measured, amounting to almost 50% of the measured cross section. The
ratio of data to DWIA calculation is 0.4 for both the p- and s-shells. At w=330
MeV, well below the maximum of the quasielastic peak, the continuum cross
section is much smaller and the ratio of data to DWIA calculation is 0.85 for
the p-shell and 1.0 for the s-shell. We infer that one or more mechanisms that
increase with transform some of the single-nucleon-knockout into
multinucleon knockout, decreasing the valence knockout cross section and
increasing the continuum cross section.Comment: 14 pages, 7 figures, Revtex (multicol, prc and aps styles), to appear
in Phys Rev
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