Family Environment, Affect, Ambivalence and Decisions About Unplanned Adolescent Pregnancy

This study investigated the relationships among family environment, demographic measures, the decisions made by unintentionally pregnant adolescents regarding post-delivery plans (stay single, get married, adoption), and the certainty with which these decisions were made. The Information Sheet, Family Environment Scale (Moos & Moos, 1981), and Multiple Affect Adjective Check List (Zuckerman & Lubin, 1965a) were administered to 17 5 pregnant adolescents, ages 14 through 22, who intended to carry their pregnancies to term. Pearson product-moment correlations and multiple regression analyses were utilized to assess the relationships between family environment and certainty of decision and between family environment and negative affect. Greater uncertainty was associated with nonwhite racial status and living with both natural parents or mother only. Higher levels of negative affect were related to lower levels of perceived family cohesion, independence, expressiveness, and intellectualcultural orientation. The demographic variables of age, trimester of pregnancy, and family constellation were also found to be useful in predicting levels of negative affect. Subjects who were older, further along in their pregnancies, and living with both natural parents or mother only tended to report greater negative affect. Findings of greater uncertainty and negative affect associated with living with the natural mother are consistent with previous reports of disturbed mother-daughter relationships among this population. Discriminant analysis revealed that subjects choosing adoption were more likely to be older and to be white than those choosing to keep the child. They also tended to perceive higher levels of expressiveness and independence in their families. Comparisons between the present sample and "normal" families revealed differences which were statistically significant, but quite small in terms of raw score units. Indeed, these groups may be more similar than has often been assumed. The implications of these findings for the delivery of services and for future research efforts in this area were discussed. More intensive assessment of family functioning is needed. Based upon present results, further investigation of the family constellation variable is warranted

On Near-Infrared H-Alpha Searches for High-Redshift Galaxies

The lack of success of Lyman-alpha searches for high-redshift (z>2) field galaxies may be due to extinction by dust, suggesting that surveys based on lines of longer wavelength, particularly H-alpha, may be more effective. To test the dust hypothesis we have undertaken deep broad- (K') and narrow-band (5000 km/s, 2.177 micron) imaging of the field towards the quasar PHL957, in an attempt to detect H-alpha emission from a known galaxy of redshift z=2.313. We cover an area of 4.9 square arcmin (0.28 h^{-2}Mpc^2) to a 4-sigma limiting narrow-band flux f=2.7x10^{-16}erg/s/cm^2, a factor of several deeper than previously published surveys. We detect the H-alpha+[N II] emission line in this galaxy at the 3.3-sigma level, inferring a star formation rate of 18 h^{-2} solar masses per year. This is a factor only a few times larger than the rate seen in some Sc galaxies today. The faint flux level reached in this work demonstrates the promise of narrow-band imaging in the near-infrared as a technique for finding normal galaxies at high redshifts.Comment: 6 pages of LaTex using mn.sty (MNRAS style). Figure 1 is an image obtainable from the Authors by FTP. Contact [email protected] for more details. Figure 2 is a Z-compressed, uuencoded postscript graph

Limits on the star formation rates of z>2 damped Ly-alpha systems from H-alpha spectroscopy

We present the results of a long-slit K-band spectroscopic search with CGS4 on UKIRT for H-alpha emission from the objects responsible for high-redshift (z > 2) damped Ly-alpha absorption systems. The objective was to measure the star-formation rates in these systems. However, no H-alpha emission was detected above our 3-sigma limits of f < 10E-19 W/m**2, corresponding to star formation rates < 10 M_sun/yr/h**2 (q_0=0.5). These upper limits are more meaningful than those from searches for Ly-alpha emission because the H-alpha line is unaffected by resonant scattering. For q_0=0.5 our limits are in conflict with the star formation rates predicted under the assumption that the high-z DLAs are the fully-formed galactic-disk counterparts of today's massive spiral galaxies. Deeper spectroscopy is needed to test this picture for q_0=0.0. A programme of NICMOS imaging observations currently underway, combined with VLT spectroscopy, will provide a detailed picture of the link between DLAs and young galaxies.Comment: 5 pages, LaTex, includes 1 encapsulated postscript figure. To appear in the proceedings of the workshop on "NICMOS and the VLT: A New Era of High Resolution Near Infrared Imaging and Spectroscopy", held in Pula, Sardinia (26-27 May 1998), eds. Wolfram Freudling et al. Uses aspconf.sty and epsf.st

Features of turbulence during wildland fires in forested and grassland environments

Fire-induced turbulence and the feedback into the fire, following ambient changes, differ for forested (sub-canopy) and grassland environments. Here, we synthesize observations from multiple experimental surface fires: two sub-canopy backing fires, one sub-canopy heading fire, and a grassland heading fire. We identify and compare the most essential coherent structures and processes of each case from the turbulent momentum fluxes and turbulent kinetic energy (TKE) budget terms. In the sub-canopy burns, turbulent eddies are strongest near the canopy top: high streamwise turbulent flux accompanies low cross-stream turbulent flux and vice versa. In the grassland fire, both streamwise and cross-stream eddies strengthen simultaneously until a certain height, informing a vertical length scale for the fire-influence. Moreover, the forward sweep from streamwise eddies assists in the fire spread by pushing hot gases towards unburnt fuel. In the sub-canopy fires, shear production and buoyancy production are more substantial near the canopy top for more intense fires, while their magnitudes decrease with decreasing fire intensity. At mid-canopy-height scales, buoyancy production dominates shear production, becoming the key mechanism for vertical transport of TKE. In the grassland fire, shear production dominates buoyancy production near the surface and is insignificant beyond a certain height relative to the flame length, while buoyancy production increases with height, becoming substantial further away from the surface. Turbulent transport terms are also active in both environments. For intense sub-canopy fires, there is a loss in TKE due to its expulsion to the boundary layer aloft via the transport term, compensated by a reversal process: TKE influx via the transport term. In the grassland fire, the transport term mimics this behavior until a certain height. The insights into the relative significance of the respective turbulent fluxes and TKE budget terms in each environment can help simplify the complex system of equations governing fire physics

Predicting Distribution of Aedes Aegypti and Culex Pipiens Complex, Potential Vectors of Rift Valley Fever Virus in Relation to Disease Epidemics in East Africa.

The East African region has experienced several Rift Valley fever (RVF) outbreaks since the 1930s. The objective of this study was to identify distributions of potential disease vectors in relation to disease epidemics. Understanding disease vector potential distributions is a major concern for disease transmission dynamics. DIVERSE ECOLOGICAL NICHE MODELLING TECHNIQUES HAVE BEEN DEVELOPED FOR THIS PURPOSE: we present a maximum entropy (Maxent) approach for estimating distributions of potential RVF vectors in un-sampled areas in East Africa. We modelled the distribution of two species of mosquitoes (Aedes aegypti and Culex pipiens complex) responsible for potential maintenance and amplification of the virus, respectively. Predicted distributions of environmentally suitable areas in East Africa were based on the presence-only occurrence data derived from our entomological study in Ngorongoro District in northern Tanzania. Our model predicted potential suitable areas with high success rates of 90.9% for A. aegypti and 91.6% for C. pipiens complex. Model performance was statistically significantly better than random for both species. Most suitable sites for the two vectors were predicted in central and northwestern Tanzania with previous disease epidemics. Other important risk areas include western Lake Victoria, northern parts of Lake Malawi, and the Rift Valley region of Kenya. Findings from this study show distributions of vectors had biological and epidemiological significance in relation to disease outbreak hotspots, and hence provide guidance for the selection of sampling areas for RVF vectors during inter-epidemic periods

Diffuse Hard X-ray Emission in Starburst Galaxies as Synchrotron from Very High Energy Electrons

[Abdriged] The origin of the diffuse hard X-ray (2 - 10 keV) emission from starburst galaxies is a long-standing problem. We suggest that synchrotron emission of 10 - 100 TeV electrons and positrons (e+/-) can contribute to this emission, because starbursts have strong magnetic fields. We consider three sources of e+/- at these energies: (1) primary electrons directly accelerated by supernova remnants; (2) pionic secondary e+/- created by inelastic collisions between CR protons and gas nuclei in the dense ISMs of starbursts; (3) pair e+/- produced between the interactions between 10 - 100 TeV gamma-rays and the intense far-infrared (FIR) radiation fields of starbursts. We create one-zone steady-state models of the CR population in the Galactic Center (R <= 112 pc), NGC 253, M82, and Arp 220's nuclei, assuming a power law injection spectrum for electrons and protons. We compare these models to extant radio and GeV and TeV gamma-ray data for these starbursts, and calculate the diffuse synchrotron X-ray and Inverse Compton (IC) luminosities of these starbursts. If the primary electron spectrum extends to ~PeV energies and has a proton/electron injection ratio similar to the Galactic value, we find that synchrotron contributes 2 - 20% of their unresolved, diffuse hard X-ray emission. Inverse Compton emission is likewise a minority of the unresolved X-ray emission in these starbursts, from 0.1% in the Galactic Center to 10% in Arp 220's nuclei. We also model generic starbursts, including submillimeter galaxies, in the context of the FIR--X-ray relation, finding that up to 2% in the densest starbursts with our fiducial assumptions. Neutrino and TeV gamma-ray data can further constrain the synchrotron X-ray emission of starbursts. Our models do not constrain hard synchrotron X-ray emission from any additional hard components of primary e+/- from sources like pulsars in starbursts.Comment: Accepted by ApJ; 31 pages, emulateapj forma

Optical techniques for 3D surface reconstruction in computer-assisted laparoscopic surgery

One of the main challenges for computer-assisted surgery (CAS) is to determine the intra-opera- tive morphology and motion of soft-tissues. This information is prerequisite to the registration of multi-modal patient-specific data for enhancing the surgeon’s navigation capabilites by observ- ing beyond exposed tissue surfaces and for providing intelligent control of robotic-assisted in- struments. In minimally invasive surgery (MIS), optical techniques are an increasingly attractive approach for in vivo 3D reconstruction of the soft-tissue surface geometry. This paper reviews the state-of-the-art methods for optical intra-operative 3D reconstruction in laparoscopic surgery and discusses the technical challenges and future perspectives towards clinical translation. With the recent paradigm shift of surgical practice towards MIS and new developments in 3D opti- cal imaging, this is a timely discussion about technologies that could facilitate complex CAS procedures in dynamic and deformable anatomical regions

A close relationship at z~2: submillimetre galaxies and BzK-selected galaxies

We investigate the relationship between two massive star-forming galaxy populations at redshift z~ 2; i.e. submillimetre galaxies (SMGs) and BzK-selected galaxies (BzKs). Out of 60 SMGs found in the Subaru/XMM-Newton deep field, we collect optical--NIR photometry of 28 radio counterparts for 24 SMGs, based on refined sky positions with a radio map for 35 SMGs (Ivison et al. 2007). We find a correlation between their K-band magnitudes and BzK [= (z-K)-(B-z)] colours: almost all of the K-faint (K_AB > 21.3) radio-detected SMGs have BzK>-0.2, and therefore BzKs. This result gives strong support to perform direct optical identification of SMGs by searching for BzKs around SMGs. We calculate the formal significance (P' value) for each of the BzK associations around radio-undetected SMGs, and find 6 new robust identifications, including one double identification. From this analysis, we obtain the current best estimate on the surface density of BzK-selected SMGs, which indicates that only ~1 per cent of BzKs are SMGs. If BzKs are normal disk-like galaxies at z~ 2 as indicated by the correlation between their star formation rate (SFR) and stellar mass and also by dynamical properties, SMGs are likely to be merging BzKs. In this case, a typical enhancement of SFR due to merging is only a factor of ~ 3, which is an order of magnitude lower than that of local ULIRGs. This may indicate that most of the merging BzKs could be observed as SMGs. Considering a possible high fraction of mergers at z~ 2 (at least it would be higher than the fraction at z> 1 of ~ 10 per cent), it is rather puzzling to find such a low fraction of SMGs in the progenitor population, i.e. BzKs.Comment: 12 pages, 7 figures, accepted for publication in MNRA