797 research outputs found
Improved Algorithm for Degree Bounded Survivable Network Design Problem
We consider the Degree-Bounded Survivable Network Design Problem: the
objective is to find a minimum cost subgraph satisfying the given connectivity
requirements as well as the degree bounds on the vertices. If we denote the
upper bound on the degree of a vertex v by b(v), then we present an algorithm
that finds a solution whose cost is at most twice the cost of the optimal
solution while the degree of a degree constrained vertex v is at most 2b(v) +
2. This improves upon the results of Lau and Singh and that of Lau, Naor,
Salavatipour and Singh
Metabolic and Subjective Results Review of the Integrated Suit Test Series
Crewmembers will perform a variety of exploration and construction activities on the lunar surface. These activities will be performed while inside an extravehicular activity (EVA) spacesuit. In most cases, human performance is compromised while inside an EVA suit as compared to a crewmember s unsuited performance baseline. Subjects completed different EVA type tasks, ranging from ambulation to geology and construction activities, in different lunar analog environments including overhead suspension, underwater and 1-g lunar-like terrain, in both suited and unsuited conditions. In the suited condition, the Mark III (MKIII) EVA technology demonstrator suit was used and suit pressure and suit weight were parameters tested. In the unsuited conditions, weight, mass, center of gravity (CG), terrain type and navigation were the parameters. To the extent possible, one parameter was varied while all others were held constant. Tests were not fully crossed, but rather one parameter was varied while all others were left in the most nominal setting. Oxygen consumption (VO2), modified Cooper-Harper (CH) ratings of operator compensation and ratings of perceived exertion (RPE) were measured for each trial. For each variable, a lower value correlates to more efficient task performance. Due to a low sample size, statistical significance was not attainable. Initial findings indicate that suit weight, CG and the operational environment can have a large impact on human performance during EVA. Systematic, prospective testing series such as those performed to date will enable a better understanding of the crucial interactions of the human and the EVA suit system and their environment. However, work remains to be done to confirm these findings. These data have been collected using only unsuited subjects and one EVA suit prototype that is known to fit poorly on a large demographic of the astronaut population. Key findings need to be retested using an EVA suit prototype better suited to a larger anthropometric portion of the astronaut population, and elements tested only in the unsuited condition need to be evaluated with an EVA suit and appropriate analog environment
Quantitative nitric oxide measurements by means of laser-induced fluorescence in a heavy-duty Diesel engine
Quantitative in-cylinder laser-induced fluorescence measurements ofnitric oxide in a heavy-duty Diesel engine are presented. Special attention is paid to experimental techniques to assess the attenuation of the laser beam and the fluorescence signal by the cylinder contents.This attenuation can be considerable at certain stages in the combustionstroke. The temperature and pressure dependence of the fluorescence signal is described in various models. In this study, LIFsim was used.Finally, calibration was realized by concentration measurements in the exhaust gas
Resistance distance, information centrality, node vulnerability and vibrations in complex networks
We discuss three seemingly unrelated quantities that have been introduced in different fields of science for complex networks. The three quantities are the resistance distance, the information centrality and the node displacement. We first prove various relations among them. Then we focus on the node displacement, showing its usefulness as an index of node vulnerability.We argue that the node displacement has a better resolution as a measure of node vulnerability than the degree and the information centrality
Bispecific PD1-IL2v and anti-PD-L1 break tumor immunity resistance by enhancing stem-like tumor-reactive CD8<sup>+</sup> T cells and reprogramming macrophages.
Immunotherapies have shown remarkable, albeit tumor-selective, therapeutic benefits in the clinic. Most patients respond transiently at best, highlighting the importance of understanding mechanisms underlying resistance. Herein, we evaluated the effects of the engineered immunocytokine PD1-IL2v in a mouse model of de novo pancreatic neuroendocrine cancer that is resistant to checkpoint and other immunotherapies. PD1-IL2v utilizes anti-PD-1 as a targeting moiety fused to an immuno-stimulatory IL-2 cytokine variant (IL2v) to precisely deliver IL2v to PD-1 <sup>+</sup> T cells in the tumor microenvironment. PD1-IL2v elicited substantial infiltration by stem-like CD8 <sup>+</sup> T cells, resulting in tumor regression and enhanced survival in mice. Combining anti-PD-L1 with PD1-IL2v sustained the response phase, improving therapeutic efficacy both by reprogramming immunosuppressive tumor-associated macrophages and enhancing T cell receptor (TCR) immune repertoire diversity. These data provide a rationale for clinical trials to evaluate the combination therapy of PD1-IL2v and anti-PD-L1, particularly in immunotherapy-resistant tumors infiltrated with PD-1 <sup>+</sup> stem-like T cells
On the Quantum Invariant for the Spherical Seifert Manifold
We study the Witten--Reshetikhin--Turaev SU(2) invariant for the Seifert
manifold where is a finite subgroup of SU(2). We show
that the WRT invariants can be written in terms of the Eichler integral of the
modular forms with half-integral weight, and we give an exact asymptotic
expansion of the invariants by use of the nearly modular property of the
Eichler integral. We further discuss that those modular forms have a direct
connection with the polyhedral group by showing that the invariant polynomials
of modular forms satisfy the polyhedral equations associated to .Comment: 36 page
The torsion cosmology in Kaluza-Klein theory
We have studied the torsion cosmology model in Kaluza-Klein theory. We
considered two simple models in which the torsion vectors are
and ,
respectively. For the first model, the accelerating expansion of the Universe
can be not explained without dark energy which is similar to that in the
standard cosmology. But for the second model, we find that without dark energy
the effect of torsion can give rise to the accelerating expansion of the
universe and the alleviation of the well-known age problem of the three old
objects for appropriated value of the model parameter . These
outstanding features of the second torsion cosmology model have been supported
by the Type Ia supernovae (SNIa) data.Comment: 12 pages, 2 figures. Accepted for publication in JCA
New exact solution of Dirac-Coulomb equation with exact boundary condition
It usually writes the boundary condition of the wave equation in the Coulomb
field as a rough form without considering the size of the atomic nucleus. The
rough expression brings on that the solutions of the Klein-Gordon equation and
the Dirac equation with the Coulomb potential are divergent at the origin of
the coordinates, also the virtual energies, when the nuclear charges number Z >
137, meaning the original solutions do not satisfy the conditions for
determining solution. Any divergences of the wave functions also imply that the
probability density of the meson or the electron would rapidly increase when
they are closing to the atomic nucleus. What it predicts is not a truth that
the atom in ground state would rapidly collapse to the neutron-like. We
consider that the atomic nucleus has definite radius and write the exact
boundary condition for the hydrogen and hydrogen-like atom, then newly solve
the radial Dirac-Coulomb equation and obtain a new exact solution without any
mathematical and physical difficulties. Unexpectedly, the K value constructed
by Dirac is naturally written in the barrier width or the equivalent radius of
the atomic nucleus in solving the Dirac equation with the exact boundary
condition, and it is independent of the quantum energy. Without any divergent
wave function and the virtual energies, we obtain a new formula of the energy
levels that is different from the Dirac formula of the energy levels in the
Coulomb field.Comment: 12 pages,no figure
Geriatric Screening, Triage Urgency, and 30-Day Mortality in Older Emergency Department Patients
BACKGROUND: Urgency triage in the emergency department (ED) is important for early identification of potentially lethal conditions and extensive resource utilization. However, in older patients, urgency triage systems could be improved by taking geriatric vulnerability into account. We investigated the association of geriatric vulnerability screening in addition to triage urgency levels with 30-day mortality in older ED patients. DESIGN: Secondary analysis of the observational multicenter Acutely Presenting Older Patient (APOP) study. SETTING: EDs within four Dutch hospitals. PARTICIPANTS: Consecutive patients, aged 70 years or older, who were prospectively included. MEASUREMENTS: Patients were triaged using the Manchester Triage System (MTS). In addition, the APOP screener was used as a geriatric screening tool. The primary outcome was 30-day mortality. Comparison was made between mortality within the geriatric high- and low-risk screened patients in every urgency triage category. We calculated the difference in explained variance of mortality by adding the geriatric screener (APOP) to triage urgency (MTS) by calculating Nagelkerke R2. RESULTS: We included 2,608 patients with a median age of 79 (interquartile range = 74-84) years, of whom 521 (20.0%) patients were categorized as high risk accor
Knowledge about systemic inflammatory response syndrome and sepsis: a survey among Dutch emergency department nurses
__Background:__ Sepsis has a high mortality. Early recognition and timely treatment are essential for patient survival. The aim of this study is to examine the factors that influence the knowledge and recognition of systemic inflammatory response syndrome (SIRS) criteria and sepsis by emergency department (ED) nurses.
__Methods:__ A prospective, multi-center study including 216 ED nurses from 11 hospitals and academic medical centers in The Netherlands was conducted in 2013. A validated questionnaire was used to evaluate ED nurses’ knowledge about SIRS and sepsis. Questions about demographic characteristics were also included, to investigate factors that may contribute to the knowledge about SIRS and sepsis.
__Results:__ The mean total score was 15.9 points, with a maximum possible score of 29 points. ED nurses employed at hospitals with a level 3 intensive care unit (ICU) scored significantly higher than their colleagues employed at hospitals with a level 1 or 2 ICU. Recently completed education in sepsis was associated with a higher score. The employees in low ICU level hospitals who reported recent education did not score significantly lower than their ICU level 3 colleagues. ED nurses over the age of 50 scored significantly lower than their younger colleagues.
__Conclusions:__ The knowledge of ED nurses concerning SIRS and sepsis rises proportionally with the level of ICU in hospitals. Recent education in sepsis raises knowledge level as well. We recommend that when there is a low exposure rate to SIRS and sepsis, more emphasis should be placed on regular education
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