12,327 research outputs found
The effect of age on referral to and use of specialist palliative care services in adult cancer patients: a systematic review
Objective: to investigate variations in the use of specialist palliative care (SPC) services for adult cancer patients, in relation to age.Design: systematic review of studies examining use of or referral to SPC services in adult cancer patients.Search strategy and selection criteria: six electronic databases (Medline, Embase, Web of Science, HMIC, SIGLE and AgeInfo) were searched for studies published between 1966 and March 2005, and references in the articles identified were also examined. Inclusion criteria were all studies which provided data on age in relation to use of or referral to SPC. Two reviewers independently selected studies, extracted data and assessed methodological quality according to defined criteria.Main outcome measures: use of or referral to SPC services, determined from all sources of report (patient, informal carer, health care professional, health care records).Results: 14 studies were identified. All reported a statistically significant lower use of SPC among older cancer patients (65 and above or older) at a univariate level [crude odds ratios ranged from 0.33 (0.15-0.72) to 0.82 (0.80-0.82)]. However, there were important methodological weaknesses in all of the studies identified; most crucially, studies failed to consider variations in use in relation to need for SPC.Conclusions: there is some evidence that older people are less likely to be referred to, or to use, SPC. These findings require confirmation in studies using prospectively collected data which control for patient's need for SPC
Fabrication techniques developed for small- diameter, thin-wall tungsten and tungsten alloy tubing
Report describes methods for the fabrication of tungsten and tungsten alloys into small-diameter, thin-wall tubing of nuclear quality. The tungsten, or tungsten alloy tube blanks are produced by double extrusion. Plug-drawing has emerged as an excellent secondary fabrication technique for the reduction of the overall tube dimensions
Non-circular features in Saturn's D ring: D68
D68 is a narrow ringlet located only 67,627 km (1.12 planetary radii) from
Saturn's spin axis. Images of this ringlet obtained by the Cassini spacecraft
reveal that this ringlet exhibits persistent longitudinal brightness variations
and a substantial eccentricity (ae=25+/-1 km). By comparing observations made
at different times, we confirm that the brightness variations revolve around
the planet at approximately the local orbital rate (1751.6 degrees/day), and
that the ringlet's pericenter precesses at 38.243+/-0.008 degrees/day,
consistent with the expected apsidal precession rate at this location due to
Saturn's higher-order gravitational harmonics. Surprisingly, we also find that
the ringlet's semi-major axis appears to be decreasing with time at a rate of
2.4+/-0.4 km/year between 2005 and 2013. A closer look at these measurements,
along with a consideration of earlier Voyager observations of this same
ringlet, suggests that the mean radius of D68 moves back and forth, perhaps
with a period of around 15 Earth years or about half a Saturn year. These
observations could place important constraints on both the ringlet's local
dynamical environment and the planet's gravitational field.Comment: 39 Pages, 11 Figures accepted for publication in Icarus Text slightly
modified to match corrections to proof
Romantic Partnerships and the Dispersion of Social Ties: A Network Analysis of Relationship Status on Facebook
A crucial task in the analysis of on-line social-networking systems is to
identify important people --- those linked by strong social ties --- within an
individual's network neighborhood. Here we investigate this question for a
particular category of strong ties, those involving spouses or romantic
partners. We organize our analysis around a basic question: given all the
connections among a person's friends, can you recognize his or her romantic
partner from the network structure alone? Using data from a large sample of
Facebook users, we find that this task can be accomplished with high accuracy,
but doing so requires the development of a new measure of tie strength that we
term `dispersion' --- the extent to which two people's mutual friends are not
themselves well-connected. The results offer methods for identifying types of
structurally significant people in on-line applications, and suggest a
potential expansion of existing theories of tie strength.Comment: Proc. 17th ACM Conference on Computer Supported Cooperative Work and
Social Computing (CSCW), 201
Entangled and disentangled evolution for a single atom in a driven cavity
For an atom in an externally driven cavity, we show that special initial
states lead to near-disentangled atom-field evolution, and superpositions of
these can lead to near maximally-entangled states. Somewhat counterintutively,
we find that (moderate) spontaneous emission in this system actually leads to a
transient increase in entanglement beyond the steady-state value. We also show
that a particular field correlation function could be used, in an experimental
setting, to track the time evolution of this entanglement
A comparison of once versus twice per week training on leg press strength in women
The purpose of this study was to compare strength differences between 2 groups of untrained women, who performed a single set of the leg press exercise once or twice per week. Methods. Twenty-one women were divided randomly into 2 groups: Group 1 (n=10) performed a single set of the leg press exercise once per week, while Group 2 (n=11) performed a single set of the leg press exercise twice per week for a period of 8 weeks. Throughout the duration of the study, an amount of resistance was utilized that allowed for a single set of 6 to 10 repetitions to muscular failure. At the conclusion of the study, subjects were tested for their 6-RM strength. A 2x2 ANOVA was used to compare strength differences. The a level was set at 0.05 in order for differences to be considered significant. Results. The 2X2 ANOVA demonstrated that strength increases were significant between tests {P=0.0001), but not significant between groups (P=0.757). Conclusion. These results indicate that performing a single set of the leg press once or twice per week results in statistically similar strength gains in untrained women
Relational Leadership: Reconceptualizing How School Districts Address Teacher Attrition
American education is in crisis. Teacher attrition rates are astronomical and continue to rise post-pandemic. In his executive summary, Pelfrey (2020), a policy and research analyst in the Georgia governor\u27s office, revealed that new teachers are abandoning their careers at steadily increasing rates within the first five years of service. As such, we must further examine teacher retention and the influence of school administrators. In this capacity, this study utilized a qualitative methodology to examine teacher attrition in a high school in Georgia. Specifically, narrative inquiry provided the framework to examine the lived experiences of teachers in this southern school. Although multiple findings emerged from the data analysis, this article focuses on relational leadership and its impact on teacher retention
Emotional Strategies as Catalysts for Cooperation in Signed Networks
The evolution of unconditional cooperation is one of the fundamental problems
in science. A new solution is proposed to solve this puzzle. We treat this
issue with an evolutionary model in which agents play the Prisoner's Dilemma on
signed networks. The topology is allowed to co-evolve with relational signs as
well as with agent strategies. We introduce a strategy that is conditional on
the emotional content embedded in network signs. We show that this strategy
acts as a catalyst and creates favorable conditions for the spread of
unconditional cooperation. In line with the literature, we found evidence that
the evolution of cooperation most likely occurs in networks with relatively
high chances of rewiring and with low likelihood of strategy adoption. While a
low likelihood of rewiring enhances cooperation, a very high likelihood seems
to limit its diffusion. Furthermore, unlike in non-signed networks, cooperation
becomes more prevalent in denser topologies.Comment: 24 pages, Accepted for publication in Advances in Complex System
Stabilizing All Geometric Moduli in Heterotic Calabi-Yau Vacua
We propose a scenario to stabilize all geometric moduli - that is, the
complex structure, Kahler moduli and the dilaton - in smooth heterotic
Calabi-Yau compactifications without Neveu-Schwarz three-form flux. This is
accomplished using the gauge bundle required in any heterotic compactification,
whose perturbative effects on the moduli are combined with non-perturbative
corrections. We argue that, for appropriate gauge bundles, all complex
structure and a large number of other moduli can be perturbatively stabilized -
in the most restrictive case, leaving only one combination of Kahler moduli and
the dilaton as a flat direction. At this stage, the remaining moduli space
consists of Minkowski vacua. That is, the perturbative superpotential vanishes
in the vacuum without the necessity to fine-tune flux. Finally, we incorporate
non-perturbative effects such as gaugino condensation and/or instantons. These
are strongly constrained by the anomalous U(1) symmetries which arise from the
required bundle constructions. We present a specific example, with a consistent
choice of non-perturbative effects, where all remaining flat directions are
stabilized in an AdS vacuum.Comment: 24 pages, 2 figure
Integrated electrical and mechanical modelling of integrated-full-electric-propulsion systems
Integrated Full Electric Propulsion (IFEP) systems are the subject of much interest at present. Current research is focused on analysing and improving aspects of subsystem and system performance. However, there is a great need to look more widely at the `multi-physics' problem of characterising the dynamic interactions between the electrical and mechanical systems. This paper will discuss the changing nature of modelling and simulation to aid research into IFEP systems, outlining the alternative angle taken by the Advanced Marine Electrical Propulsion Systems (AMEPS) project to characterise and investigate electrical-mechanical system interactions. The paper will describe this approach and highlight the unique challenges associated with the problem, discussing the suitable methods that will be adopted to address these challenges. Finally, an overview of the present and future research opportunities facilitated via the AMEPS project will be presented
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