Forest Islands in a Sea of Urban Habitat

Urban forests are poorly defined as ecological communities. Substantive links between anthropogenic landscape features and forest ecology are lacking. ‘Urbaness’ is commonly defined by human population density or land use classifications, but their use is inconsistent throughout the literature, and rarely is linked with ecological processes. Furthermore, it is unknown whether urban forests are functioning parts of a patchy urban woodland system or isolated islands amidst an ocean of unsuitable habitat. I first used digital satellite imagery and publicly available U.S. National Park data to link urban land use with forest processes. I then linked those land use classifications with the potential for urban forests to regenerate by investigating tree recruitment in the greater Buffalo, NY (U.S.) metropolitan area. If urban forests link with the greater regional forest ecosystem, then tree species richness should resemble the regional forests. However, if the urban forest patches are isolated, they should contain a subset of the regional forest richness with recruitment limited by forest patch size. Heavy urban cover predicted reduced tree and seedling richness and abundance. Moreover, tree seedling richness decreased with increasing urban land use. Tree seedling richness and abundance both declined when invasive species were present, suggesting invasive species may act as a barrier to tree recruitment. Tree recruitment was more strongly linked with forest patch size than the regional species pool, and active dispersal was limited to wind-dispersed species between urban forests. These results suggest that urban forests are isolated forest islands surrounded by an ocean of urban habitat

Intravaginal cytomegalovirus (CMV) challenge elicits maternal viremia and results in congenital transmission in a guinea pig model

<p>Abstract</p> <p>Background</p> <p>The objective of this study was to compare intravaginal (ivg) and subcutaneous (sc) administration of the guinea pig cytomegalovirus (GPCMV) in pregnant and non-pregnant guinea pigs. These studies tested the hypotheses that ivg infection would elicit immune responses, produce maternal viremia, and lead to vertical transmission, with an efficiency similar to the traditionally employed sc route.</p> <p>Results</p> <p>Four groups of age- and size-matched guinea pigs were studied. Two groups were pregnant, and two groups were not pregnant. Animals received 5x10⁵plaque-forming units (PFU) of a GPCMV reconstituted from an infectious bacterial artificial chromosome (BAC) construct containing the full-length GPCMV genome. Seroconversion was compared by IgG ELISA, and viremia (DNAemia) was monitored by PCR. In both pregnant and non-pregnant animals, sc inoculation resulted in significantly higher serum ELISA titers than ivg inoculation at 8 and 12 weeks post-infection. Patterns of viremia (DNAemia) were similar in animals inoculated by either sc or ivg route. However, in pregnant guinea pigs, animals inoculated by both routes experienced an earlier onset of DNAemia than did non-pregnant animals. Neither the percentage of dead pups nor the percentage of GPCMV positive placentas differed by inoculation route.</p> <p>Conclusions</p> <p>In the guinea pig model of congenital CMV infection, the ivg route is as efficient at causing congenital infection as the conventional but non-physiologic sc route. This finding could facilitate future experimental evaluation of vaccines and antiviral interventions in this highly relevant animal model.</p

Modeling of Shock Tunnel Aeroheating Data on the Mars Science Laboratory Aeroshell

A series of shots are run in the T5 shock tunnel at California Institute of Technology to measure heating levels on a 70 blunt cone at angle of attack in an environment representative of the Mars Science Laboratory entry. Twenty shots are obtained in CO₂ over a range of enthalpies and pressures chosen to span the laminar and turbulent flow regimes. The data indicate that the lee side turbulent heating augmentation predicted by flight simulations is valid and must be accounted for during the design of the thermal protection system. Computational fluid dynamic simulations are generally in good agreement with the laminar data when employing a supercatalytic wall model, whereas turbulent simulations are in reasonable agreement when a noncatalytic wall model is used. The reasons for this discrepancy are unknown at this time. The turbulent heating augmentation is shown to be inversely related to freestream enthalpy. Changes in angle of attack between 11 and 16 are shown to have minimal impact on measured and computed heating. A transition criterion based on momentum thickness Reynolds number, analogous to that used in flight predictions, predicts onset with reasonable accuracy, although transition is observed to occur later than the current design criterion indicates

Systems Analysis for a Venus Aerocapture Mission

Previous high level analysis has indicated that significant mass savings may be possible for planetary science missions if aerocapture is employed to place a spacecraft in orbit. In 2001 the In-Space Propulsion program identified aerocapture as one of the top three propulsion technologies for planetary exploration but that higher fidelity analysis was required to verify the favorable results and to determine if any supporting technology gaps exist that would enable or enhance aerocapture missions. A series of three studies has been conducted to assess, from an overall system point of view, the merit of using aerocapture at Titan, Neptune and Venus. These were chosen as representative of a moon with an atmosphere, an outer giant gas planet and an inner planet. The Venus mission, based on desirable science from plans for Solar System Exploration and Principal Investigator proposals, to place a spacecraft in a 300km polar orbit was examined and the details of the study are presented in this paper

Preliminary Convective-Radiative Heating Environments for a Neptune Aerocapture Mission

Convective and radiative heating environments have been computed for a three-dimensional ellipsled configuration which would perform an aerocapture maneuver at Neptune. This work was performed as part of a one-year Neptune aerocapture spacecraft systems study that also included analyses of trajectories, atmospheric modeling, aerodynamics, structural design, and other disciplines. Complementary heating analyses were conducted by separate teams using independent sets of aerothermodynamic modeling tools (i.e. Navier-Stokes and radiation transport codes). Environments were generated for a large 5.50 m length ellipsled and a small 2.88 m length ellipsled. Radiative heating was found to contribute up to 80% of the total heating rate at the ellipsled nose depending on the trajectory point. Good agreement between convective heating predictions from the two Navier-Stokes solvers was obtained. However, the radiation analysis revealed several uncertainties in the computational models employed in both sets of codes, as well as large differences between the predicted radiative heating rates

Case Report Botulinum Toxin Injections for Simple Partial Motor Seizures Associated with Pain

Intractable epilepsy with painful partial motor seizures is a relatively rare and difficult disorder to treat. We evaluated the usefulness of botulinum toxin to reduce ictal pain. Two patients received two or four botulinum toxin (BTX) injections at one-to-two-month intervals. Patient 1 had painful seizures of the right arm and hand. Patient 2 had painful seizures involving the left foot and leg. Injections were discontinued after improved seizure control following resective surgery. Both patients received significant pain relief from the injections with analgesia lasting at least two months. Seizure severity was reduced, but seizure frequency and duration were unaffected. For these patients, BTX was effective in temporarily relieving pain associated with muscle contraction in simple partial motor seizures. Our findings do not support the hypothesis that modulation of motor end-organ feedback affects focal seizure generation. BTX is a safe and reversible treatment that should be considered as part of adjunctive therapy after failure to achieve control of painful partial motor seizures

Botulinum Toxin Injections for Simple Partial Motor Seizures Associated with Pain

Intractable epilepsy with painful partial motor seizures is a relatively rare and difficult disorder to treat. We evaluated the usefulness of botulinum toxin to reduce ictal pain. Two patients received two or four botulinum toxin (BTX) injections at one-to-two-month intervals. Patient 1 had painful seizures of the right arm and hand. Patient 2 had painful seizures involving the left foot and leg. Injections were discontinued after improved seizure control following resective surgery. Both patients received significant pain relief from the injections with analgesia lasting at least two months. Seizure severity was reduced, but seizure frequency and duration were unaffected. For these patients, BTX was effective in temporarily relieving pain associated with muscle contraction in simple partial motor seizures. Our findings do not support the hypothesis that modulation of motor end-organ feedback affects focal seizure generation. BTX is a safe and reversible treatment that should be considered as part of adjunctive therapy after failure to achieve control of painful partial motor seizures