4,463 research outputs found
Transmitter switch for high-power microwave output
Combiner system can be used for combining output powers of two transmitters or for switching from one to the other. This can be done when pair of transmitters operate on same frequency and carriers are phase coherent as by excitation from single exciter
A Cross-cohort Description of Young Peopleās Housing Experience in Britain over 30 Years: An Application of Sequence Analysis
Methods. Sequence Analysis supported by Event History Analysis. Key Findings. Despite only 12 years separating both cohorts, the younger 1970 cohort exhibited very different patterns of housing including a slower progression out of the parental home and into stable tenure, and an increased reliance on privately rented housing. Returns to the parental home occurred across the twenties and into the thirties in both cohorts, although occurred more frequently and were more concentrated among certain groups in the 1970 cohort compared to the 1958 cohort. Although fewer cohort members in the 1970 cohort experienced social housing, and did so at a later age, social housing was also associated with greater tenure immobility in this younger cohort. Conclusions. The housing experiences of the younger cohort became associated with more unstable tenure (privately rented housing) for the majority. Leaving the parental home was observed to be a process, as opposed to a one-off event, and several returns to the parental home were documented, more so for the 1970 cohort. These findings are not unrelated, and in the current environment of rising house prices, collapses in the (youth) labour market and rising costs of higher education, are likely to increase in prevalence across subsequent cohorts
Extreme Supernova Models for the Superluminous Transient ASASSN-15lh
The recent discovery of the unprecedentedly superluminous transient
ASASSN-15lh (or SN 2015L) with its UV-bright secondary peak challenges all the
power-input models that have been proposed for superluminous supernovae. Here
we examine some of the few viable interpretations of ASASSN-15lh in the context
of a stellar explosion, involving combinations of one or more power inputs. We
model the lightcurve of ASASSN-15lh with a hybrid model that includes
contributions from magnetar spin-down energy and hydrogen-poor circumstellar
interaction. We also investigate models of pure circumstellar interaction with
a massive hydrogen-deficient shell and discuss the lack of interaction features
in the observed spectra. We find that, as a supernova ASASSN-15lh can be best
modeled by the energetic core-collapse of a ~40 Msun star interacting with a
hydrogen-poor shell of ~20 Msun. The circumstellar shell and progenitor mass
are consistent with a rapidly rotating pulsational pair-instability supernova
progenitor as required for strong interaction following the final supernova
explosion. Additional energy injection by a magnetar with initial period of 1-2
ms and magnetic field of 0.1-1 x 10^14 G may supply the excess luminosity
required to overcome the deficit in single-component models, but this requires
more fine-tuning and extreme parameters for the magnetar, as well as the
assumption of efficient conversion of magnetar energy into radiation. We thus
favor a single-input model where the reverse shock formed in a strong SN
ejecta-CSM interaction following a very powerful core-collapse SN explosion can
supply the luminosity needed to reproduce the late-time UV-bright plateau.Comment: 8 pages, 3 figure
Transit-Oriented Development: The Quest for Sustainable Cities in the Age of the Automobile
During the early and mid-twentieth century the automobile captured the imagination of the American public. Superhighways, which were the vision, became the reality with the promise of speedy and safe travel. During this visioning, little attention was given to the impacts the highway system would have on urban America. Of course, by the end of the century the impacts were quite clear and distressing. Traffic congestion and air pollution became, and now are, among the most challenging aspects of life in American cities. In contemplating measures to alleviate the negative effects of these twin challenges, federal, state, and local agencies, encouraged by the environmental movement and transit advocacy, have promoted transit-oriented development (āTODā) as a potential remedy. Paralleling efforts in foreign cities like Munich and Singapore, U.S. cities including Denver, Atlanta, Indianapolis, San Diego, and Somerville (MA) have all invested themselves in urban development projects built at public transit nodes aimed at building walkable, bikeable communities that provide mobility from home to work and recreational sites without the use of automobiles. In the process, TOD has had to deal with its own set of issues from funding and value capture to zoning and low-income housing. This Article provides an in-depth study of five American and two international TOD projects in an attempt to discover the variety among approaches to TOD and some of the issues TOD raises
Some Empirical Criteria for Attributing Creativity to a Computer Program
Peer reviewedPostprin
Fractal templates in the escape dynamics of trapped ultracold atoms
We consider the dynamic escape of a small packet of ultracold atoms launched
from within an optical dipole trap. Based on a theoretical analysis of the
underlying nonlinear dynamics, we predict that fractal behavior can be seen in
the escape data. This data would be collected by measuring the time-dependent
escape rate for packets launched over a range of angles. This fractal pattern
is particularly well resolved below the Bose-Einstein transition temperature--a
direct result of the extreme phase space localization of the condensate. We
predict that several self-similar layers of this novel fractal should be
measurable and we explain how this fractal pattern can be predicted and
analyzed with recently developed techniques in symbolic dynamics.Comment: 11 pages with 5 figure
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Psychological distress after stroke and aphasia: the first six months
Objective: We explored the factors that predicted psychological distress in the first six months post stroke in a sample including people with aphasia.
Design: Prospective longitudinal observational study.
Setting and subjects: Participants with a first stroke from two acute stroke units were assessed while still in hospital (baseline) and at three and six months post stroke.
Main measures: Distress was assessed with the General Health Questionnaire-12. Other measures included: NIH Stroke Scale, Barthel Index, Frenchay Aphasia Screening Test, Frenchay Activities Index, MOS Social Support Scale and social network indicators. Logistic regression was used to identify predictors of distress at each stage post stroke; and to determine what baseline factors predicted distress at six months.
Results: Eighty-seven participants were able to self-report on measures used, of whom 32 (37%) had aphasia. 71 (82%) were seen at six months, including 11 (16%) with aphasia. Predictors of distress were: stroke severity at baseline; low social support at three months; and loneliness and low satisfaction with social network at six months. The baseline factors that predicted distress at six months were psychological distress, loneliness and low satisfaction with social network (Nagelkerke R2 = 0.49). Aphasia was not a predictor of distress at any time point. Yet, at three months post stroke 93% of those with aphasia experienced high distress, as opposed to 50% of those without aphasia (Ļ2 (1) = 8.61, P<0.01).
Conclusions: Factors contributing to distress after stroke vary across time. Loneliness and low satisfaction with oneās social network are particularly important and contribute to long-term psychological distress
A Domestic Consequence of the Government Spying on Its Citizens: The Guilty Go Free
In recent years, a seemingly endless stream of headlines have alerted people to the steady and relentless government encroachment on their civil liberties. Consider, for example, headlines such as āU.S. Directs Agents to Cover Up Program Used to Investigate Americans,ā āDEA Admits to Keeping Secret Database of Phone Calls,ā or āNo Morsel Too Miniscule for All-Consuming N.S.A.ā Of concern is not only the U.S. governmentās collection of data on its citizens, but also how that information is aggregated, stored, and used. The Fourth Amendment protects citizens from unreasonable searches and seizures by the government. While the drafters of the Fourth Amendment could not have foreseen the advent of contemporary electronic surveillance measures, it has been suggested that some forms of electronic surveillance come within the protection of the Amendment and trigger the requirement that such a search be reasonable. If the Fourteenth Amendment applies to electronic surveillance, then so does the exclusionary rule, which excludes evidence of guilt that has been obtained as a result of an unlawful search and seizure.
A question to consider when assessing the reach of the exclusionary rule is whether it can be used in response to the militaryās unlawful surveillance of civilians. Such was the question at issue in the Ninth Circuitās decision in United States v. Dreyer, a case involving the conviction of a child pornographer who was first brought to the attention of local authorities through information shared by the military. In September 2014, a three-judge panel of the Ninth Circuit found the militaryās involvement in civilian affairs to be especially troubling, since such involvement is specifically curtailed by the Posse Comitatus Act, and the court ruled in favor of applying the exclusionary rule to suppress the evidence. Although the Ninth Circuit ultimately reversed in an en banc decision, the courtās initial ruling remains instructive for its application of the exclusionary rule in a situation of perceived military overreach, and that initial ruling remains the focus of this article as evidence of the need for Congress to provide clear guidance in this area.
It was the first federal appeals court case to invoke the exclusionary rule as a response to a PCA violation since the enactment of the PCA in 1878. Moreover, recent Supreme Court jurisprudence suggests that the exclusionary rule is losing favor. In light of this shift, an important question emerges: Was the Ninthās Circuitās ruling in Dreyer simply an anomaly, or was it the beginning of a trend of courts policing government overreach? This article argues that, in a post-9/11 society in which constitutional protections are increasingly uncertain, congressional action is necessary to ensure effective enforcement of the PCA. Dreyer indicates that in lieu of legislation clarifying the applicability of the PCA, the judiciary will be forced to assume the role of gatekeeper of individual liberties. It has been said that ā[p]ower tends to corrupt and absolute power corrupts absolutely.ā The Ninth Circuitās stinging response to the governmentās defense in Dreyer illustrates the courtās belief that the judiciary has a responsibility to curtail the governmentās assertion of a broad set of surveillance powers over its citizens. Against the backdrop of an unprecedented amount of governmental spying on citizens and recent reports of covert sharing of information between the National Security Agency (NSA) and the Drug Enforcement Agency (DEA), the Ninth Circuit has made clear that absent self-restraint by government agents, it will step in to curtail abuses by rejecting evidence seized through government overreach
A Domestic Consequence of the Government Spying on Its Citizens: The Guilty Go Free
In recent years, a seemingly endless stream of headlines have alerted people to the steady and relentless government encroachment on their civil liberties. Consider, for example, headlines such as āU.S. Directs Agents to Cover Up Program Used to Investigate Americans,ā āDEA Admits to Keeping Secret Database of Phone Calls,ā or āNo Morsel Too Miniscule for All-Consuming N.S.A.ā Of concern is not only the U.S. governmentās collection of data on its citizens, but also how that information is aggregated, stored, and used. The Fourth Amendment protects citizens from unreasonable searches and seizures by the government. While the drafters of the Fourth Amendment could not have foreseen the advent of contemporary electronic surveillance measures, it has been suggested that some forms of electronic surveillance come within the protection of the Amendment and trigger the requirement that such a search be reasonable. If the Fourteenth Amendment applies to electronic surveillance, then so does the exclusionary rule, which excludes evidence of guilt that has been obtained as a result of an unlawful search and seizure.
A question to consider when assessing the reach of the exclusionary rule is whether it can be used in response to the militaryās unlawful surveillance of civilians. Such was the question at issue in the Ninth Circuitās decision in United States v. Dreyer, a case involving the conviction of a child pornographer who was first brought to the attention of local authorities through information shared by the military. In September 2014, a three-judge panel of the Ninth Circuit found the militaryās involvement in civilian affairs to be especially troubling, since such involvement is specifically curtailed by the Posse Comitatus Act, and the court ruled in favor of applying the exclusionary rule to suppress the evidence. Although the Ninth Circuit ultimately reversed in an en banc decision, the courtās initial ruling remains instructive for its application of the exclusionary rule in a situation of perceived military overreach, and that initial ruling remains the focus of this article as evidence of the need for Congress to provide clear guidance in this area.
It was the first federal appeals court case to invoke the exclusionary rule as a response to a PCA violation since the enactment of the PCA in 1878. Moreover, recent Supreme Court jurisprudence suggests that the exclusionary rule is losing favor. In light of this shift, an important question emerges: Was the Ninthās Circuitās ruling in Dreyer simply an anomaly, or was it the beginning of a trend of courts policing government overreach? This article argues that, in a post-9/11 society in which constitutional protections are increasingly uncertain, congressional action is necessary to ensure effective enforcement of the PCA. Dreyer indicates that in lieu of legislation clarifying the applicability of the PCA, the judiciary will be forced to assume the role of gatekeeper of individual liberties. It has been said that ā[p]ower tends to corrupt and absolute power corrupts absolutely.ā The Ninth Circuitās stinging response to the governmentās defense in Dreyer illustrates the courtās belief that the judiciary has a responsibility to curtail the governmentās assertion of a broad set of surveillance powers over its citizens. Against the backdrop of an unprecedented amount of governmental spying on citizens and recent reports of covert sharing of information between the National Security Agency (NSA) and the Drug Enforcement Agency (DEA), the Ninth Circuit has made clear that absent self-restraint by government agents, it will step in to curtail abuses by rejecting evidence seized through government overreach
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