284 research outputs found
Aspects of ex-nuptiality in New Zealand : toward a social demography of marriage and the family since the second world war
Traditionally in most Western countries religiously based social
norms have held that sexual activity should be engaged in only within
formally celebrated marital unions, which in turn should be regarded
as lifelong. Nowhere have these norms ever been universally adhered
to, especially by men, but in the last two to three decades they have
been rejected on an unprecedented scale. Rising levels of nonmarital
pregnancy, marital breakdown, and, more recently, informal
cohabitation have been held in some quarters to greatly endanger the
institutions of marriage and the family.
Recognising the ease with which they can be misinterpreted, this
thesis provides a comprehensive analysis of socio-demographic data
pertaining to changing patterns of nonmarital sexual behaviour and
changing attitudes to marriage and the family in New Zealand since the
Second World War. Trends in nonmarital (and in particular premarital)
pregnancy and childbearing, marriage and coresidence at marriage, and
divorce are examined in detail. The study also explores changes in
the pattern of placement of children born ex-nuptially, some of the
personal consequences of childbearing following ex-nuptial conception,
factors associated with divorce, and trends in the involvement of
children in divorce. The drawing together of these phenomena within a
single conceptual framework emphasises their joint reflection of
forces for social change which have been operating in New Zealand.
The evolutionary character of social change is stressed at
several points. The wresting of control over courtship, mate selection, and the decision when to marry from parents by young people
of the affluent 1950s is seen as having in many ways initiated the
process. Among the forces recognised as having built on this
foundation are the assumption of further generational independence by
the young, pressure for, and achievement of, greater equality and
independence by women, major improvements in women’s ability to
control their fertility, and arisng out of these things a much more
individualistic central set of values.
Evidence presented suggests that by the latter half of the 1970s
the more permissive sexual morality which successive youth cohorts
have developed had acquired a certain maturity. It was being
practised more openly and with greater ideological conviction. It was
also leading less frequently to unplanned parenthood and early
marriage. Indeed marriage was generally being approached much more
cautiously, and had possibly been rejected altogether in some
quarters. The former tendency may augur well for marital stability in
the future, and due allowance must be made for the fact that recent
instability has been partly the product of a unique, and temporary,
combination of circumstances. On the other hand values and priorities
which have assumed increased importance in domestic relations have in
the process rendered marriage and the family inherently more fragile
institutions
Nonequilibrium and Nonlinear Dynamics in Geomaterials I : The Low Strain Regime
Members of a wide class of geomaterials are known to display complex and
fascinating nonlinear and nonequilibrium dynamical behaviors over a wide range
of bulk strains, down to surprisingly low values, e.g., 10^{-7}. In this paper
we investigate two sandstones, Berea and Fontainebleau, and characterize their
behavior under the influence of very small external forces via carefully
controlled resonant bar experiments. By reducing environmental effects due to
temperature and humidity variations, we are able to systematically and
reproducibly study dynamical behavior at strains as low as 10^{-9}. Our study
establishes the existence of two strain thresholds, the first, epsilon_L, below
which the material is essentially linear, and the second, epsilon_M, below
which the material is nonlinear but where quasiequilibrium thermodynamics still
applies as evidenced by the success of Landau theory and a simple macroscopic
description based on the Duffing oscillator. At strains above epsilon_M the
behavior becomes truly nonequilibrium -- as demonstrated by the existence of
material conditioning -- and Landau theory no longer applies. The main focus of
this paper is the study of the region below the second threshold, but we also
comment on how our work clarifies and resolves previous experimental conflicts,
as well as suggest new directions of research.Comment: 14 pages, 15 figure
Hydrological and associated biogeochemical consequences of rapid global warming during the Paleocene-Eocene Thermal Maximum
The Paleocene-Eocene Thermal Maximum (PETM) hyperthermal, ~ 56 million years ago (Ma), is the most dramatic example of abrupt Cenozoic global warming. During the PETM surface temperatures increased between 5 and 9 °C and the onset likely took < 20 kyr. The PETM provides a case study of the impacts of rapid global warming on the Earth system, including both hydrological and associated biogeochemical feedbacks, and proxy data from the PETM can provide constraints on changes in warm climate hydrology simulated by general circulation models (GCMs). In this paper, we provide a critical review of biological and geochemical signatures interpreted as direct or indirect indicators of hydrological change at the PETM, explore the importance of adopting multi-proxy approaches, and present a preliminary model-data comparison. Hydrological records complement those of temperature and indicate that the climatic response at the PETM was complex, with significant regional and temporal variability. This is further illustrated by the biogeochemical consequences of inferred changes in hydrology and, in fact, changes in precipitation and the biogeochemical consequences are often conflated in geochemical signatures. There is also strong evidence in many regions for changes in the episodic and/or intra-annual distribution of precipitation that has not widely been considered when comparing proxy data to GCM output. Crucially, GCM simulations indicate that the response of the hydrological cycle to the PETM was heterogeneous – some regions are associated with increased precipitation – evaporation (P – E), whilst others are characterised by a decrease. Interestingly, the majority of proxy data come from the regions where GCMs predict an increase in PETM precipitation. We propose that comparison of hydrological proxies to GCM output can be an important test of model skill, but this will be enhanced by further data from regions of model-simulated aridity and simulation of extreme precipitation events
Terrestrial environmental change across the onset of the PETM and the associated impact on biomarker proxies:A cautionary tale
The following supplementary information includes one dataset which contains 3 tables:
Biomarker distributions and proxies at Cobham, UK
Bulk and compound specific isotope data at Cobham (UK)
Model-derived mean annual surface temperature and precipitation estimates as a function of CO2 at Cobham (UK)
Competitive stochastic noises in coherently driven two-level atoms and quantum interference
A system of coherently-driven two-level atoms is analyzed in presence of two
independent stochastic perturbations: one due to collisions and a second one
due to phase fluctuations of the driving field. The behaviour of the quantum
interference induced by the collisional noise is considered in detail. The
quantum-trajectory method is utilized to reveal the phase correlations between
the dressed states involved in the interfering transition channels. It is shown
that the quantum interference induced by the collisional noise is remarkably
robust against phase noise. This effect is due to the fact that the phase
noise, similarly to collisions, stabilizes the phase-difference between the
dressed states.Comment: accepted for publication in J. Opt.
Hyperspectral remote sensing of cyanobacterial pigments as indicators for cell populations and toxins in eutrophic lakes
The growth of mass populations of toxin-producing cyanobacteria is a serious concern for the ecological
status of inland waterbodies and for human and animal health. In this study we examined the performance
of four semi-analytical algorithms for the retrieval of chlorophyll a (Chl a) and phycocyanin (C-PC) from data
acquired by the Compact Airborne Spectrographic Imager-2 (CASI-2) and the Airborne Imaging Spectrometer
for Applications (AISA) Eagle sensor. The retrieval accuracies of the semi-analytical models were
compared to those returned by optimally calibrated empirical band-ratio algorithms. The best-performing
algorithm for the retrieval of Chl a was an empirical band-ratio model based on a quadratic function of the
ratio of re!ectance at 710 and 670 nm (R2=0.832; RMSE=29.8%). However, this model only provided a
marginally better retrieval than the best semi-analytical algorithm. The best-performing model for the
retrieval of C-PC was a semi-analytical nested band-ratio model (R2=0.984; RMSE=3.98 mg m−3). The
concentrations of C-PC retrieved using the semi-analytical model were correlated with cyanobacterial cell
numbers (R2=0.380) and the particulate and total (particulate plus dissolved) pools of microcystins
(R2=0.858 and 0.896 respectively). Importantly, both the empirical and semi-analytical algorithms were
able to retrieve the concentration of C-PC at cyanobacterial cell concentrations below current warning
thresholds for cyanobacteria in waterbodies. This demonstrates the potential of remote sensing to contribute
to early-warning detection and monitoring of cyanobacterial blooms for human health protection at regional
and global scales
Justification of the symmetric damping model of the dynamical Casimir effect in a cavity with a semiconductor mirror
A "microscopic" justification of the "symmetric damping" model of a quantum
oscillator with time-dependent frequency and time-dependent damping is given.
This model is used to predict results of experiments on simulating the
dynamical Casimir effect in a cavity with a photo-excited semiconductor mirror.
It is shown that the most general bilinear time-dependent coupling of a
selected oscillator (field mode) to a bath of harmonic oscillators results in
two equal friction coefficients for the both quadratures, provided all the
coupling coefficients are proportional to a single arbitrary function of time
whose duration is much shorter than the periods of all oscillators. The choice
of coupling in the rotating wave approximation form leads to the "mimimum
noise" model of the quantum damped oscillator, introduced earlier in a pure
phenomenological way.Comment: 9 pages, typos corrected, corresponds to the published version,
except for the reference styl
Decomposing socioeconomic inequality for binary health outcomes: an improved estimation that does not vary by choice of reference group
BACKGROUND Decomposition of concentration indices yields useful information regarding the relative importance of various determinants of inequitable health outcomes. But the two estimation approaches to decomposition in current use are not suitable for binary outcomes. FINDINGS The paper compares three estimation approaches for decomposition of inequality concentration indices: Ordinary Least Squares (OLS), probit, and the Generalized Linear Model (GLM) binomial distribution and identity link. Data are from the Thai Health and Welfare Survey 2003. The OLS estimates do not take into account the binary nature of the outcome and the probit estimates depend on the choice of reference groups, whereas the GLM binomial identity approach has neither of these problems. CONCLUSIONS The GLM with binomial distribution and identity link allows the inequality decomposition model to hold, and produces valid estimates of determinants that do not vary according to choice of reference groups. This GLM approach is readily available in standard statistical packages.The study was conducted under the auspices of the overarching project "The Thai Health-Risk Transition: a National Cohort Study", funded by the Wellcome Trust UK (GR071587 MA) and the Australian National Health and Medical Research Council (268055)
Going to sleep in the supine position is a modifiable risk factor for late pregnancy stillbirth; findings from the New Zealand multicentre stillbirth case-control study
Objective: Our objective was to test the primary hypothesis that maternal non-left, in particular supine going-to-sleep position, would be a risk factor for late stillbirth (≥28 weeks of gestation). Methods: A multicentre case-control study was conducted in seven New Zealand health regions, between February 2012 and December 2015. Cases (n=164) were women with singleton pregnancies and late stillbirth, without congenital abnormality. Controls (n=569) were women with on-going singleton pregnancies, randomly selected and frequency matched for health region and gestation. The primary outcome was adjusted odds of late stillbirth associated with self-reported going-to-sleep position, on the last night. The last night was the night before the late stillbirth was thought to have occurred or the night before interview for controls. Going to- sleep position on the last night was categorised as: supine, left-side, right-side, propped or restless. Multivariable logistic regression adjusted for known confounders. Results: Supine going-to-sleep position on the last night was associated with increased late stillbirth risk (adjusted odds ratios (aOR) 3.67, 95% confidence interval (CI) 1.74 to 7.78) with a population attributable risk of 9.4%. Other independent risk factors for late stillbirth (aOR, 95% CI) were: BMI (1.04, 1.01 to 1.08) per unit, maternal age ≥40 (2.88, 1.31 to 6.32), birthweight <10th customised centile (2.76, 1.59 to 4.80), and <6 hours sleep on the last night (1.81, 1.14 to 2.88). The risk associated with supine-going-to sleep position was greater for term (aOR 10.26, 3.00 to 35.04) than preterm stillbirths (aOR 3.12, 0.97 to 10.05). Conclusions: Supine going-to-sleep position is associated with a 3.7 fold increase in overall late stillbirth risk, independent of other common risk factors. A public health campaign encouraging women not to go-to-sleep supine in the third trimester has potential to reduce late stillbirth by approximately 9%
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