380 research outputs found
Public Policy for Suburban Integration...The Case for New Communities
In this Article we examine the integration experience of one type of suburban community - new communities developed from the ground up - to determine whether integration has been beneficial to blacks and low- and moderate-income households, whether it is acceptable to the affluent white majority, and whether new community development is a desirable means of fostering integration
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Family Health Development in Life Course Research: A Scoping Review of Family Functioning Measures.
BACKGROUND AND OBJECTIVES: Our objective is to identify common family functioning measurement tools and assess their compatibility with family-health development and life-course perspectives. METHODS: Data sources include PubMed, ERIC, CINAHL, Families and Societies Worldwide, PsychInfo, Web of Science, PsychNet, and Health and Psychosocial Instruments. Title and abstract screening and full-text review of articles were conducted by multiple reviewers based on prespecified inclusion criteria. Data extraction focused on features of identified measurements tools, including: (1) name (2) domains of family functioning measured, (3) established psychometric properties, and (4) original context of psychometric evaluation (eg, details about the study sample). RESULTS: Of the 50 measurement tools identified, 94% measured organizational patterns (eg, flexibility, connectedness, or resources), 46% measured belief systems (eg, making meaning of adversity, or positive outlook), and 54% measured communication processes (eg, open emotional sharing, or collaborative problem-solving). CONCLUSIONS: Existing measures of family functioning can aid life-course researchers in understanding family processes as contexts for health and well-being. There also remain opportunities to refine or develop measures of family functioning more compatible with a life-course perspective that assess family processes (1) at various life stages; (2) with various backgrounds, identities, structures, and experiences; and (3) embedded in or impacted by various contexts that may facilitate or hinder family functioning
Coherence control for qubits
We study the influence of an external driving field on the coherence
properties of a qubit under the influence of bit-flip noise. In the presence of
driving, two paradigmatic cases are considered: (i) a field that results for a
suitable choice of the parameters in so-called coherent destruction of
tunneling and (ii) one that commutes with the static qubit Hamiltonian. In each
case, we give for high-frequency driving a lower bound for the coherence time.
This reveals the conditions under which the external fields can be used for
coherence stabilization.Comment: 15 pages, 1 figur
Temperature effects on zoeal morphometric traits and intraspecific variability in the hairy crab Cancer setosus across latitude
International audiencePhenotypic plasticity is an important but often ignored ability that enables organisms, within species-specific physiological limits, to respond to gradual or sudden extrinsic changes in their environment. In the marine realm, the early ontogeny of decapod crustaceans is among the best known examples to demonstrate a temperature-dependent phenotypic response. Here, we present morphometric results of larvae of the hairy crab , the embryonic development of which took place at different temperatures at two different sites (Antofagasta, 23°45′ S; Puerto Montt, 41°44′ S) along the Chilean Coast. Zoea I larvae from Puerto Montt were significantly larger than those from Antofagasta, when considering embryonic development at the same temperature. Larvae from Puerto Montt reared at 12 and 16°C did not differ morphometrically, but sizes of larvae from Antofagasta kept at 16 and 20°C did, being larger at the colder temperature. Zoea II larvae reared in Antofagasta at three temperatures (16, 20, and 24°C) showed the same pattern, with larger larvae at colder temperatures. Furthermore, larvae reared at 24°C, showed deformations, suggesting that 24°C, which coincides with temperatures found during strong EL Niño events, is indicative of the upper larval thermal tolerance limit.  is exposed to a wide temperature range across its distribution range of about 40° of latitude. Phenotypic plasticity in larval offspring does furthermore enable this species to locally respond to the inter-decadal warming induced by El Niño. Morphological plasticity in this species does support previously reported energetic trade-offs with temperature throughout early ontogeny of this species, indicating that plasticity may be a key to a species' success to occupy a wide distribution range and/or to thrive under highly variable habitat conditions
The barycentric motion of exoplanet host stars: tests of solar spin-orbit coupling
Empirical evidence suggests a tantalising but unproven link between various
indicators of solar activity and the barycentric motion of the Sun. The latter
is exemplified by transitions between regular and more disordered motion
modulated by the motions of the giant planets, and rare periods of retrograde
motion with negative orbital angular momentum. An examination of the
barycentric motion of exoplanet host stars, and their stellar activity cycles,
has the potential of proving or disproving the Sun's motion as an underlying
factor in the complex patterns of short- and long-term solar variability
indices, by establishing whether such correlations exist in other planetary
systems. A variety of complex patterns of barycentric motions of exoplanet host
stars is demonstrated, depending on the number, masses and orbits of the
planets. Each of the behavioural types proposed to correlate with solar
activity are also evident in exoplanet host stars: repetitive patterns
influenced by massive multiple planets, epochs of rapid change in orbital
angular momentum, and intervals of negative orbital angular momentum. The study
provides the basis for independent investigations of the widely-studied but
unproven suggestion that the Sun's motion is somehow linked to various
indicators of solar activity. We show that, because of the nature of their
barycentric motions, the host stars HD168443 and HD74156 offer particularly
powerful tests of this hypothesis.Comment: 7 pages, 3 figures. Accepted for publication in A&
Molecular and atomic line surveys of galaxies I: the dense, star-forming phase as a beacon
We predict the space density of molecular gas reservoirs in the Universe, and
place a lower limit on the number counts of carbon monoxide (CO), hydrogen
cyanide (HCN) molecular and [CII] atomic emission lines in blind redshift
surveys in the submillimeter-centimeter spectral regime. Our model uses: (a)
recently available HCN Spectral Line Energy Distributions (SLEDs) of local
Luminous Infrared Galaxies (LIRGs, L_IR>10^11 L_sun), (b) a value for
epsilon=SFR/M_dense(H_2) provided by new developments in the study of star
formation feedback on the interstellar medium and (c) a model for the evolution
of the infrared luminosity density. Minimal 'emergent' CO SLEDs from the dense
gas reservoirs expected in all star-forming systems in the Universe are then
computed from the HCN SLEDs since warm, HCN-bright gas will necessarily be
CO-bright, with the dense star-forming gas phase setting an obvious minimum to
the total molecular gas mass of any star-forming galaxy. We include [CII] as
the most important of the far-infrared cooling lines. Optimal blind surveys
with the Atacama Large Millimeter Array (ALMA) could potentially detect very
distant (z~10-12) [CII] emitters in the >ULIRG galaxy class at a rate of ~0.1-1
per hour (although this prediction is strongly dependent on the star formation
and enrichment history at this early epoch), whereas the (high-frequency)
Square Kilometer Array (SKA) will be capable of blindly detecting z>3 low-J CO
emitters at a rate of ~40-70 per hour. The [CII] line holds special promise for
the detection of metal-poor systems with extensive reservoirs of CO-dark
molecular gas where detection rates with ALMA can reach up to 2-7 per hour in
Bands 4-6.Comment: 16 pages, 9 figures, accepted for publication in Ap
Phase diffusion as a model for coherent suppression of tunneling in the presence of noise
We study the stabilization of coherent suppression of tunneling in a driven
double-well system subject to random periodic function ``kicks''. We
model dissipation due to this stochastic process as a phase diffusion process
for an effective two-level system and derive a corresponding set of Bloch
equations with phase damping terms that agree with the periodically kicked
system at discrete times. We demonstrate that the ability of noise to localize
the system on either side of the double-well potenital arises from overdamping
of the phase of oscillation and not from any cooperative effect between the
noise and the driving field. The model is investigated with a square wave
drive, which has qualitatively similar features to the widely studied
cosinusoidal drive, but has the additional advantage of allowing one to derive
exact analytic expressions.Comment: 17 pages, 4 figures, submitted to Phys. Rev.
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