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We use simultaneous multi-wavelength BVRI-JHK photometric observations of cataclysmic variables (CVs) to determine the inclination angles of the systems, together with phase-resolved spectroscopy to calculate the K2 and vsini. We then calculate the masses of the system components. We are using these data to construct mass-radius diagrams of the secondaries in an effort to resolve some of the debate over their evolutionary history.
We combine HST and ground-based parallaxes for cataclysmic variables (CVs) to examine their outburst energetics, as well as the nature of their secondary stars. Harrison et al. (2004) have recently published parallaxes for WZ Sge, YZ Cnc, and RU Peg, and have reanalyzed the HST parallaxes for U Gem, SS Aur, and SS Cyg. Combined with existing HST parallaxes for RW Tri (MeArthur et al. 1999), TV Col (MeArthur et al. 2001), EX Hya and V1223 Sgr (Beuermann et al. 2004a,b), ten high-quality parallaxes are available to constrain the various types of outbursts of CVs. In addition, Thorstensen (2003) has published ground-based parallaxes for fourteen CV systems.
During the four years the Sample Preparation Laboratory (SPL) at the National Ocean Sciences Accelerator Mass Spectrometer (NOSAMS) Facilty has been in operation we have accumulated much data from which we can assess our progress. We evaluate our procedural blanks here and describe modifications in our procedures that have improved our analyses of older samples. In the SPL, we convert three distinct types of samples—seawater, CaCO3 and organic carbon—to CO2 prior to preparing graphite for the accelerator and have distinct procedural blanks for each procedure. Dissolved inorganic carbon (∑CO2) is extracted from acidified seawater samples by sparging with a nitrogen carrier gas. We routinely analyze “line blanks” by processing CO2 from a 14C-dead source through the entire stripping procedure. Our hydrolysis blank, IAEA C-1, is prepared by acidifying in vacuo with 100% H3PO4 at 60° overnight, identical to our sample preparation. We use a dead graphite, NBS-21, or a commercially available carbon powder for our organic combustion blank; organic samples are combusted at 850° for 5 h using CuO to provide the oxidant. Analysis of our water stripping data suggests that one step in the procedure contributes the major portion of the line blank. At present, the contribution from the line blank has no effect on our seawater analyses (fraction modern (fm) between 0.7 and 1.2). Our hydrolysis blanks can have an fm value as low as 0.0006, but are more routinely between 0.0020 and 0.0025. The fm of our best organic combustion blanks is higher than those routinely achieved in other laboratories and we are currently altering our methods to reduce it.
We have compiled the largest magnitude limited sample of candidate substellar Pleiads to date. We fit King profiles to their spatial distribution to determine the Pleiades brown dwarf core radius to be Subsequently we have used our improved spatial model to place stringent limits on the shape of the cluster mass function across and below the stellar/substellar regime. We find this to be a power law with index α = 0.41±0.08 (0.3M⊙ ≥M≥ 0.035M⊙). Extrapolation of this mass function to M= 0.012M⊙ indicates that brown dwarfs contribute only ~ 2% to the total mass of the cluster hence we conclude that brown dwarfs do not contribute significantly to disk dark matter.
We report on the Hubble Space Telescope (HST) observation of the polar, QS Tel, made during 1994 June. Orbital modulation is present in both the continuum and lines. A narrow dip is observed in the continuum folded light curve. The spectrum of the occulted source during this dip is broadly consistent in shape with the Rayleigh-Jeans tail of the EUV source.
Polar deciduous forests were an important biome during much of the Mesozoic and Paleogene, occupying upwards of 40% of the total land surface. Little is known about their physiological ecology, however, because these types of forests do not exist for study today. Furthermore, the role of high atmospheric CO2 levels in modulating the physiological response of ancient polar forests is poorly known. Here we report detailed measurements of whole-tree net carbon uptake over a full annual cycle for five tree species whose close ancestors were components of Cretaceous and Paleogene polar forests. Measurements were made on both evergreen and deciduous species after two years growth in a simulated Mesozoic polar (69°N) environment at either ambient (400 ppmv) or elevated (800 ppmv) levels of CO2. The deciduous species exhibited a significant pulse in carbon uptake during the late summer and early autumn (August to mid-October) that enabled them to achieve annual carbon budgets similar to those of evergreen trees, despite incurring higher carbon losses through annual leaf shedding. Area-based photosynthetic rates dropped progressively in all species during the polar summer (June to mid-July), resulting in decreases in whole-tree carbon uptake late in the polar summer. The high-CO2-grown trees were more strongly affected by this polar summer depression than the low-CO2-grown trees. Our results indicate that, from a carbon balance perspective, deciduous taxa have no clear advantage over evergreens. Moreover, the seasonal patterns reported here suggest that at latitudes poleward of 69°, evergreens will be even more strongly favored. The consideration of factors not directly related to carbon budgeting is probably therefore required to fully understand the adaptive significance of the deciduous leaf habit in ancient polar forests.
The all-sky radio continuum map at 408 MHz presented at this symposium by Haslam et al. can be interpreted in terms of the large-scale 3-dimensional distribution of synchrotron emissivity in the Galaxy when due allowance is made for the thermal emission. Its derivation from a 2-dimensional map must involve a number of assumptions so it is instructive to compare the results of alternative approaches (described in detail in forthcoming papers by the present authors). In both cases the variation of emissivity in the galactic plane is obtained from the observed intensity profile at b=0o and then the z-variation is chosen to give the best fit to the complete map. The observed profile is shown in the figure with and without the contributions of catalogued supernova remnants and HII regions.
In traditional transit timing variations (TTVs) analysis of multi-planetary systems, the individual TTVs are first derived from transit fitting and later modelled using n-body dynamic simulations to constrain planetary masses. We show that fitting simultaneously the transit light curves with the system dynamics (photo-dynamical model) increases the precision of the TTV measurements and helps constrain the system architecture. We exemplify the advantages of applying this photo-dynamical model to a multi-planetary system found in K2 data very close to 3:2 mean motion resonance, K2-19. In this case the period of the larger TTV variations (libration period) is much longer (>1.5 years) than the duration of the K2 observations (80 days). However, our method allows to detect the short period TTVs produced by the orbital conjunctions between the planets that in turn permits to uniquely characterise the system. Therefore, our method can be used to constrain the masses of near-resonant systems even when the full libration curve is not observed.
Little is known about the relative extent of crime against people with
severe mental illness (SMI).
To assess the prevalence and impact of crime among people with SMI
compared with the general population.
A total of 361 psychiatric patients were interviewed using the national
crime survey questionnaire, and findings compared with those from 3138
general population controls participating in the contemporaneous national
Past-year crime was experienced by 40% of patients v.
14% of controls (adjusted odds ratio (OR) = 2.8, 95% CI 2.0–3.8); and
violent assaults by 19% of patients v. 3% of controls
(adjusted OR = 5.3, 95% CI 3.1–8.8). Women with SMI had four-, ten- and
four-fold increases in the odds of experiencing domestic, community and
sexual violence, respectively. Victims with SMI were more likely to
report psychosocial morbidity following violence than victims from the
People with SMI are at greatly increased risk of crime and associated
morbidity. Violence prevention policies should be particularly focused on
people with SMI.
Domestic and sexual violence are significant public health problems but little is known about the extent to which men and women with severe mental illness (SMI) are at risk compared with the general population. We aimed to compare the prevalence and impact of violence against SMI patients and the general population.
Three hundred and three randomly recruited psychiatric patients, in contact with community services for ⩾1 year, were interviewed using the British Crime Survey domestic/sexual violence questionnaire. Prevalence and correlates of violence in this sample were compared with those from 22 606 general population controls participating in the contemporaneous 2011/12 national crime survey.
Past-year domestic violence was reported by 27% v. 9% of SMI and control women, respectively [odds ratio (OR) adjusted for socio-demographics, aOR 2.7, 95% confidence interval (CI) 1.7–4.0], and by 13% v. 5% of SMI and control men, respectively (aOR 1.6, 95% CI 1.0–2.8). Past-year sexual violence was reported by 10% v. 2.0% of SMI and control women respectively (aOR 2.9, 95% CI 1.4–5.8). Family (non-partner) violence comprised a greater proportion of overall domestic violence among SMI than control victims (63% v. 35%, p < 0.01). Adulthood serious sexual assault led to attempted suicide more often among SMI than control female victims (53% v. 3.4%, p < 0.001).
Compared to the general population, patients with SMI are at substantially increased risk of domestic and sexual violence, with a relative excess of family violence and adverse health impact following victimization. Psychiatric services, and public health and criminal justice policies, need to address domestic and sexual violence in this at-risk group.
The link between the experience of peer victimization (PV) and future psychological maladjustment has been consistently documented; however, little is known about intermediary cognitive processes that underlie this relation or how these processes vary across childhood. The present study examined the prospective relations between physical and relational PV and the development of negative and positive automatic thoughts and self-cognitions. Self-reports of cognitions and peer nomination measures of victimization were obtained from 1,242 children and young adolescents (Grades 3 through 6) in a two-wave longitudinal study. The results revealed that PV predicted significant increases in negative views of the self, world, and future and decreases in self-perceived competence for girls under 11 years of age, with the effect being stronger for younger girls. PV was not significantly associated with changes in positive or negative self-cognitions for older girls or for boys of any age. These findings support the hypothesis that PV may be linked to future psychopathology through its influence on self-cognitions, but only for girls.
The small mission A-STAR (All-Sky Transient Astrophysics Reporter) aims to locate the
X-ray counterparts to ALIGO and other gravitational wave detector sources, to study the
poorly-understood low luminosity gamma-ray bursts, and to find a wide variety of transient
high-energy source types, A-STAR will survey the entire available sky twice per 24 hours.
The payload consists of a coded mask instrument, Owl, operating in the novel low energy
band 4−150 keV, and a sensitive wide-field focussing soft X-ray instrument, Lobster,
working over 0.15−5 keV. A-STAR will trigger on ~100 GRBs/yr, rapidly
distributing their locations.
Complex nonlinear optical materials comprising elemental, compound or alloy quantum dots embedded in appropriate dielectric or semiconducting hosts may be suitable for deployment in photonic devices. Ion implantation, ion exchange followed by ion implantation, and pulsed laser deposition have all been used to synthesize these materials. However, the correlation between the parameters of energetic-beam synthesis and the nonlinear optical properties is still very rudimentary when one starts to ask what is happening at nanoscale dimensions. Systems integration of corplex nonlinear optical materials requires that the mesoscale materials science be well understood within the context of device structures. We discuss the effects of beam energy and energy density on quantum-dot size and spatial distribution, thermal conductivity, quantum-dot composition, crystallinity and defects — and, in turn, on the third-order optical susceptibility of the composite material. Examples from recent work in our laboratories are used to illustrate these effects.
Recent results from inelastic neutron scattering studies on Ce0.9Th0.1 are used to demonstrate the importance of electron-phonon coupling to the physical properties of f-electron bonded metals. In the case of Ce0.9Th0.1, the phonon density of states (DOS) of α-phase shows a significant softening when heated but shows no change across the α-γ transition despite the 11% volume change. This is supported by analysis of the magnetic spectra showing that most of the transition entropy can be accounted for with the crystal field and spin fluctuations. The precursor phonon softening, the lack of any phonon change across the transition, the magnetic spectra, and the volume transition itself can all be explained in terms of the atomic displacement sensitivity of the hybridization of the local f-electrons with conduction electrons. The electron-phonon coupling resulting from these displacement-sensitive electronic states appears to be essential to understanding cerium. Some of the behavior characteristic of these states, a large volume changes and precursor phonon softening, occurs in many other f-electron bonded metals suggesting that the phenomena is not unique to cerium.
Tropical wetlands are of great ecological importance and are worthy of widespread and vigorous conservation efforts. They are, however, very susceptible to environmental changes which often result from human activities. Waigani swamp near Port Moresby, Papua New Guinea, comprises a number of small, shallow lakes, the largest of which, Waigani Lake, has a surface area of 120 ha. This Lake now has nutrient-rich water with very high phytoplankton populations owing to sewage effluent disposal.
Changes in the macrophyte flora and vegetation of Waigani Lake are documented in aerial photographs taken between 1942 and 1981. From 1942 to 1956 the Lake was dominated by emergent vegetation, and there was very little open water. Between 1956 and 1966 this emergent vegetation was replaced by dense stands of nymphaeids. In 1965, sewage disposal into Waigani Lake began and by 1974 only a few small stands of nymphaeids remained. By 1978 no nymphaeids could be found in Waigani Lake. The decline in the nymphaeid cover of Waigani Lake was accompanied by a regression of the surrounding reed-swamp. Two other lakes near Port Moresby are nutrient-poor and have a dominant and diverse macrophyte flora, being probably more comparable with Waigani Lake prior to its enrichment—apart from a recent takeover by a pestiferous free-floating water-fern.