1,879 research outputs found
A model for the screen printing of Newtonian fluids
A preliminary investigation into aspects of the off-contact screen-printing process is presented. A mathematical model for the printing of a thin film of Newtonian fluid is proposed, in which the screen is modelled as a permeable membrane, and the entire region above and below the screen is flooded. By drawing upon widely used industrial circuit printing practices, the distinguished limit of greatest interest to this industry is identified. Numerical and asymptotic solutions of this distinguished limit are presented that reproduce many of the features observed in industrial screen-printing
Probing Spectral Line Gradients Beyond One Effective Radius in NGC 3610
The outer region (0.75--1.25 r_e in the B-band) of the merger-remnant
elliptical NGC 3610 is studied using extremely high signal to noise Keck
spectra, with a supplementary spectrum of the galaxy center. Stellar population
parameters -- age, [Z/H], [/Fe] -- are measured in several apertures
along the slit. Using the multi-index simultaneous fitting method of Proctor et
al. (2004), no significant stellar population gradients are detected in the
outer parts of the galaxy. The overall gradients relative to the galaxy center
are consistent with those found in many other early-type galaxies, though the
metallicity gradient is much steeper than would be expected if NGC 3610 formed
in a major merger event. Standard analysis methods using the H index are
found to produce spurious radially variable gradients.Comment: 15 pages, 9 figures, accepted by A
A Qualitative Analysis of Women's Short Accounts of Labour and Birth in a Western Australian Public Tertiary Hospital
This paper reports the findings of the postnatal qualitative arm of a larger study,which investigated women's prenatal and postnatal levels of childbirth fear. Women's expectations and experiences of labour and birth in a Western Australian public tertiary hospital were identified following thematic analysis of short written accounts from 141 participants who had given birth in the previous 6 to 14 weeks. Four major categories emerged to describe features and mediating factors in the trajectory of childbirth and the early puerperium "Anticipating Labour and Birth", "Labour and birth Depicted", "Mediating Factors and their consequences" and "Evaluating, Resolving, and Looking Ahead" portray women's comparative reflections on expectations and realities of birth, on mediating influences, and on moving on from their experience. These findings will provide maternity care professionals with insight into the personal and environmental features of the childbirth setting which colours women's recollections. Being aware of what women value during labour and birth will reinforce the need for professionals to provide care using a mindful approach that considers the potential psychological, emotional and behavioural implications of events
Slow-Speed Supernovae from the Palomar Transient Factory: Two Channels
Since the discovery of the unusual prototype SN 2002cx, the eponymous class
of low-velocity, hydrogen-poor supernovae has grown to include at most another
two dozen members identified from several heterogeneous surveys, in some cases
ambiguously. Here we present the results of a systematic study of 1077
hydrogen-poor supernovae discovered by the Palomar Transient Factory, leading
to nine new members of this peculiar class. Moreover we find there are two
distinct subclasses based on their spectroscopic, photometric, and host galaxy
properties: The "SN 2002cx-like" supernovae tend to be in later-type or more
irregular hosts, have more varied and generally dimmer luminosities, have
longer rise times, and lack a Ti II trough when compared to the "SN
2002es-like" supernovae. None of our objects show helium, and we counter a
previous claim of two such events. We also find that these transients comprise
5.6+17-3.7% (90% confidence) of all SNe Ia, lower compared to earlier
estimates. Combining our objects with the literature sample, we propose that
these subclasses have two distinct physical origins.Comment: 49 pages, 36 figures, submitted to Ap
Oscillation mode frequencies of 61 main sequence and subgiant stars observed by Kepler
Solar-like oscillations have been observed by Kepler and CoRoT in several
solar-type stars, thereby providing a way to probe the stars using
asteroseismology.
We provide the mode frequencies of the oscillations of various stars required
to perform a comparison with those obtained from stellar modelling.
We used a time series of nine months of data for each star. The 61 stars
observed were categorised in three groups: simple, F-like and mixed-mode. The
simple group includes stars for which the identification of the mode degree is
obvious. The F-like group includes stars for which the identification of the
degree is ambiguous. The mixed-mode group includes evolved stars for which the
modes do not follow the asymptotic relation of low-degree frequencies.
Following this categorisation, the power spectra of the 61 main sequence and
subgiant stars were analysed using both maximum likelihood estimators and
Bayesian estimators, providing individual mode characteristics such as
frequencies, linewidths, and mode heights. We developed and describe a
methodology for extracting a single set of mode frequencies from multiple sets
derived by different methods and individual scientists. We report on how one
can assess the quality of the fitted parameters using the likelihood ratio test
and the posterior probabilities.
We provide the mode frequencies of 61 stars (with their 1-sigma error bars),
as well as their associated echelle diagrams.Comment: 83 pages, 17 figures, 61 tables, paper accepted by Astronomy and
Astrophysic
Generating mixtures of spatial qubits
In a recent letter [Phys. Rev. Lett. 94, 100501 (2005)], we presented a
scheme for generating pure entangled states of spatial qudits (-dimensional
quantum systems) by using the momentum transverse correlation of the parametric
down-converted photons. In this work we discuss a generalization of this
process to enable the creation of mixed states. With the technique proposed we
experimentally generated a mixture of two spatial qubits.Comment: To appear in Optics Communication
Asteroseismology of solar-type stars with K2
We present the first detections by the NASA K2 Mission of oscillations in
solar-type stars, using short-cadence data collected during K2 Campaign\,1
(C1). We understand the asteroseismic detection thresholds for C1-like levels
of photometric performance, and we can detect oscillations in subgiants having
dominant oscillation frequencies around . Changes to the
operation of the fine-guidance sensors are expected to give significant
improvements in the high-frequency performance from C3 onwards. A reduction in
the excess high-frequency noise by a factor of two-and-a-half in amplitude
would bring main-sequence stars with dominant oscillation frequencies as high
as into play as potential asteroseismic targets for
K2.Comment: Accepted for publication in PASP; 16 pages, 2 figure
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âDead people donât claimâ: A psychopolitical autopsy of UK austerity suicides
One of the symptoms of post financial crisis austerity in the UK has been an increase in the numbers of suicides, especially by people who have experienced welfare reform. This article develops and utilises an analytic framework of psychopolitical autopsy to explore media coverage of âausterity suicideâ and to take seriously the psychic life of austerity (internalisation, shame, anxiety), embedding it in a context of social dis-ease.
Drawing on three distinct yet interrelated areas of literature (the politics of affect and psychosocial dynamics of welfare, post and anti-colonial psychopolitics, and critical suicidology), the article aims to better understand how austerity âkillsâ. Key findings include understanding austerity suicides as embedded within an affective economy of the anxiety caused by punitive welfare retrenchment, the stigmatisation of being a recipient of benefits, and the internalisation of market logic that assigns value through âproductivityâ and conceptualises welfare entitlement as economic âburdenâ. The significance of this approach lies in its ability to widen analytic framing of suicide from an individual and psychocentric focus, to illuminate culpability of government reforms while still retaining the complexity of suicide, and thus to provide relevant policy insights about welfare reform
Kepler-432: a red giant interacting with one of its two long period giant planets
We report the discovery of Kepler-432b, a giant planet ()
transiting an evolved star with an orbital period of days. Radial velocities (RVs) reveal that
Kepler-432b orbits its parent star with an eccentricity of , which we also measure independently with
asterodensity profiling (AP; ), thereby confirming
the validity of AP on this particular evolved star. The well-determined
planetary properties and unusually large mass also make this planet an
important benchmark for theoretical models of super-Jupiter formation.
Long-term RV monitoring detected the presence of a non-transiting outer planet
(Kepler-432c; days), and adaptive optics imaging revealed a nearby
(0\farcs87), faint companion (Kepler-432B) that is a physically bound M dwarf.
The host star exhibits high signal-to-noise asteroseismic oscillations, which
enable precise measurements of the stellar mass, radius and age. Analysis of
the rotational splitting of the oscillation modes additionally reveals the
stellar spin axis to be nearly edge-on, which suggests that the stellar spin is
likely well-aligned with the orbit of the transiting planet. Despite its long
period, the obliquity of the 52.5-day orbit may have been shaped by star-planet
interaction in a manner similar to hot Jupiter systems, and we present
observational and theoretical evidence to support this scenario. Finally, as a
short-period outlier among giant planets orbiting giant stars, study of
Kepler-432b may help explain the distribution of massive planets orbiting giant
stars interior to 1 AU.Comment: 22 pages, 19 figures, 5 tables. Accepted to ApJ on Jan 24, 2015
(submitted Nov 11, 2014). Updated with minor changes to match published
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