2,798 research outputs found
Weak values and the Leggett-Garg inequality in solid-state qubits
An implementation of weak values is investigated in solid-state qubits. We
demonstrate that a weak value can be non-classical if and only if a
Leggett-Garg inequality can also be violated. Generalized weak values are
described, where post-selection on a range of weak measurement results.
Imposing classical weak values permits the derivation of Leggett-Garg
inequalities for bounded operators. Our analysis is presented in terms of
kicked quantum nondemolition measurements on a quantum double-dot charge qubit.Comment: 4 pages, 2 figure
Continuous phase amplification with a Sagnac interferometer
We describe a weak value inspired phase amplification technique in a Sagnac
interferometer. We monitor the relative phase between two paths of a slightly
misaligned interferometer by measuring the average position of a split-Gaussian
mode in the dark port. Although we monitor only the dark port, we show that the
signal varies linearly with phase and that we can obtain similar sensitivity to
balanced homodyne detection. We derive the source of the amplification both
with classical wave optics and as an inverse weak value.Comment: 5 pages, 4 figures, previously submitted for publicatio
Large-scale instabilities in a non-rotating turbulent convection
Formation of large-scale coherent structures in a turbulent convection via
excitation of large-scale instability is studied. The redistribution of the
turbulent heat flux due to non-uniform large-scale motions plays a crucial role
in the formation of the coherent large-scale structures in the turbulent
convection. The modification of the turbulent heat flux results in strong
reduction of the critical Rayleigh number (based on the eddy viscosity and
turbulent temperature diffusivity) required for the excitation of the
large-scale instability. The mean-field equations which describe the
large-scale instability, are solved numerically. We determine the key
parameters that affect formation of the large-scale coherent structures in the
turbulent convection. In particular, the degree of thermal anisotropy and the
lateral background heat flux strongly modify the growth rates of the
large-scale instability, the frequencies of the generated convective-shear
waves and change the thresholds required for the excitation of the large-scale
instability. This study elucidates the origins of the large-scale circulations
and rolls in the atmospheric convective boundary layers and the meso-granular
structures in the solar convection.Comment: 13 pages, 13 figures, Physics of Fluids, in pres
Koori voices: Self-harm, suicide attempts, arrests and substance use among Aboriginal and Torres Strait Islander adolescents following residential treatment
Background: Complex interacting social, economic and historical factors influence the availability and uptake of alcohol and drugs, including among Indigenous communities. Self-harm and suicide as well as homelessness and incarceration, can both precede and result from drug and alcohol use. Rates of self-harm, suicide and incarceration among Aboriginal and Torres Strait Islander people in Australia are among the highest in the world and drug and alcohol treatment programs need to address these underlying complexities. This study examines whether an 'holistic' residential drug and alcohol treatment program for adolescents, with over 30% of clients identifying as Aboriginal and Torres Strait Islander, can improve outcomes post-discharge, including reducing self-harm, suicide attempts, arrests and alcohol and drug use. The program addresses substance use, mental health, employment, accommodation, social/community and family life. Program admission and 3 months' post-discharge data from 2007 to 2016 were analysed. Results: From 2007 to 2016, 619 Aboriginal and Torres Strait Islander young people were admitted to the program; 247 stayed in the program for 30 days or more; 89 were successfully followed up three months post-discharge to determine whether there was a significant improvement from baseline using the McNemar's Test and the Wilcoxon Signed Ranks Test. On admission, 18 people (20%) of the study population reported attempting suicide in the last 3 months and 23 people (30%) reported self-harm. Most had been engaged in the criminal justice system, with 67 people (75%) having been to court and 62 people (70%) arrested one or more times in the past 3 months, with 35 people (41%) in unstable housing, reporting having lived in three or more places in the previous 6 months. At 3 months post-treatment, all (n = 18) who reported suicide attempts in the 3 months prior to admission reported no attempts in the prior 3 months at follow-up. There was also a significant reduction in self-harm with 23 young people out of the 27 who reported self-harm at baseline not reporting self-harm at follow up (85%) and in the proportion of adolescents who reported using cannabis, amphetamines and alcohol, as well as a reduction in the proportion who reported being arrested. Conclusions: The findings provide support for an 'holistic' residential treatment program as an approach to improve health and related outcomes for Aboriginal and Torres Strait Islander young people. In addition to a focus on multiple aspects of a young person's life in treatment, culturally relevant modes of treatment and support should be a future focus to further strengthen programs when Aboriginal and Torres Strait Islander young people are over-represented in the client group
Mortality among young people seeking residential treatment for problematic drug and alcohol use: A data linkage study.
Background
Young people with problematic alcohol and other drug (AOD) use are often referred to residential treatment. Subsequent mortality rates among this high-risk group is not known. This study estimates mortality rates and determines causes of death amongst young people referred to residential treatment in Sydney, Australia.
Design
Retrospective data linkage study. Data of young people (13–18 years) referred to a residential treatment service 2001–2015 (n = 3256) linked with Australian death registration data, and followed up to 16 years (2001–2016).
Methods
Mortality rates (CMRs) and standardised mortality ratios (SMRs, age-, gender-, calendar-year-adjusted) calculated using population mortality rates. Causes of death were analysed using ICD-10 codes for AOD-induced, AOD as contributory and non-AOD related causes.
Results
During follow-up of the cohort (28,838 person-years), 63 people died (71.4 % males; 48 % Indigenous; median age at death = 21.9 years; median follow-up = 5.1years), with 76 % dying before aged 25 years. Overall mortality (SMR = 4.91, 95 % CI: 3.8−6.2; CMR = 2.18/1000 person-years, 95 % CI: 1.7−2.8) was significantly higher than age-gender-matched general population, particularly in females (SMR = 9.55; males: SMR = 4.11; RR: 2.3, 95 % CI: 1.3–4.1). SMRs were not significantly different between treatment groups (SMRs>5.5) and non-attend group (SMR = 3.7) (p = 0.359). Two-thirds of deaths involved AOD, with AOD-induced deaths comprising 42 % and AOD as contributory for 22 % deaths. Overdose, mainly opioids (including opiates), suicide, and transport accidents were major causes of deaths.
Conclusion
Very high mortality rates, particularly among females, and the high incidence of overdose and suicide emphasise early screening for those at high-risk, targeted and culturally appropriate interventions, and maximised continuing after-care accessible to young people
Continuous Phase Amplification with a Sagnac Interferometer
We describe a phase-amplification technique using a Sagnac interferometer. We monitor the relative phase between two paths of a precisely misaligned interferometer by measuring the average position of a split-Gaussian mode in the dark port. Although we monitor only the dark port, we show that the signal varies linearly with phase and that we can obtain similar sensitivity to balanced homodyne detection. We derive the source of the amplification using classical wave optics
Spectropolarimetry of SN 2011dh in M51: geometric insights on a Type IIb supernova progenitor and explosion
We present seven epochs of spectropolarimetry of the Type IIb supernova (SN)
2011dh in M51, spanning 86 days of its evolution. The first epoch was obtained
9 days after the explosion, when the photosphere was still in the depleted
hydrogen layer of the stripped-envelope progenitor. Continuum polarization is
securely detected at the level of P~0.5% through day 14 and appears to diminish
by day 30, which is different from the prevailing trends suggested by studies
of other core-collapse SNe. Time-variable modulations in P and position angle
are detected across P-Cygni line features. H-alpha and HeI polarization peak
after 30 days and exhibit position angles roughly aligned with the earlier
continuum, while OI and CaII appear to be geometrically distinct. We discuss
several possibilities to explain the evolution of the continuum and line
polarization, including the potential effects of a tidally deformed progenitor
star, aspherical radioactive heating by fast-rising plumes of Ni-56 from the
core, oblique shock breakout, or scattering by circumstellar material. While
these possibilities are plausible and guided by theoretical expectations, they
are not unique solutions to the data. The construction of more detailed
hydrodynamic and radiative-transfer models that incorporate complex aspherical
geometries will be required to further elucidate the nature of the polarized
radiation from SN 2011dh and other Type IIb supernovae.Comment: Post-proof edit. Accepted to MNRAS 2015 Aug 1
Perceived Dangerousness Mediates Punitive Attitudes Toward Sex Offenders: Results From a Vignette Experiment
The current study used an experimental vignette (n = 1,093) to examine the effects of perpetrator sex and age, and victim sex and age, on simulated juror sentencing recommendations for individuals convicted of sexual offenses (ICSO). Path analyses were used to see if differences in punitive attitudes could be explained by perceptions of dangerousness participants attached to experimentally manipulated variables, as hypothesized by attribution theorists. Results show that participants consistently recommended longer sentences, higher fines, and indicated greater support for post-release sanctions for male offenders, older perpetrators, and for offenders who victimized younger adolescents. Path analysis demonstrated that perceptions of dangerousness partially mediated the relationship between experimentally manipulated predictor variables and recommended sentence length, providing partial support for attribution theory
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