Interspecific crosses were made between perennial sowthistle (Sonchus arvensis L.) and annual sowthistle (Sonchus oleraceus L.). Flower head size, leaf type, and creeping root growth of the hybrid were intermediate to those same morphological characteristics of the parents. Backcrosses to the parents produced plants which resembled annual or perennial sowthistle more closely than did the F1 hybrids. Annual sowthistle and backcrosses to annual sowthistle were more tolerant to (2,4-dichlorophenoxy)acetic acid (2,4-D) and 3,6-dichloro-o-anisic acid (dicamba) than were perennial sowthistle or backcrosses to perennial sowthistle. However, annual and perennial sowthistle were similar to each other in response to 4-amino-3,5,6-trichloropicolinic acid (picloram). Natural crosses between annual and perennial sowthistles may account for some of the variability in herbicide response found in perennial sowthistle.

Introduction: On August 29, 2005, Hurricane Katrina made landfall along the US Gulf Coast, resulting in the evacuation of >1.5 million people, including nearly 6000 physicians. This article examines the relocation patterns of physicians following the storm, determines the impact that the disaster had on their lives and practices, and identifies lessons learned.

Methods: An Internet-based survey was conducted among licensed physicians reporting addresses within Federal Emergency Management Agency–designated disaster zones in Louisiana and Mississippi. Descriptive data analysis was used to describe respondent characteristics. Multivariate logistic regression was performed to identify the factors associated with physician nonreturn to original practice. For those remaining relocated out of state, bivariate analysis with χ2 or Fisher exact test was used to determine factors associated with plans to return to original practice.

Results: A total of 312 eligible responses were collected. Among disaster zone respondents, 85.6% lived in Louisiana and 14.4% resided in Mississippi before the hurricane struck. By spring 2006, 75.6% (n = 236) of the respondents had returned to their original homes, whereas 24.4% (n = 76) remained displaced. Factors associated with nonreturn to original employment included family or general medicine practice (OR 0.42, 95% CI 0.17–1.04; P = .059) and severe or complete damage to the workplace (OR 0.24, 95% CI 0.13–0.42; P < .001).

Conclusions: A sizeable proportion of physicians remain displaced after Hurricane Katrina, along with a lasting decrease in the number of physicians serving in the areas affected by the disaster. Programs designed to address identified physician needs in the aftermath of the storm may give confidence to displaced physicians to return. (Disaster Med Public Health Preparedness. 2007;1:21–26)

Light emitting electroluminescent devices have been studied in which the conjugated light emitting polymer is separated on both sides from the device electrodes by a film of nonconducting polyaniline. The devices operate under an AC applied potential.Aluminum, copper or gold serve as the metal electrodes. Flexible, completely organic polymer dispersed liquid crystal light valves have been fabricated from transparent plastic substrates on which a conducting film of polypyrrole has been deposited. A new concept, “microcontact printing”, is being investigated for patterning the polypyrrole.

We describe bilayer structures comprised of a poly (p-phenylene vinylene) (PPV) layer and a trap-free diaryldiamine (TPD) doped in polycarbonate (PC) layer, sandwiched between indium-tin-oxide (ITO) and aluminum (Al) contacts. Two critical phenomena in the operation of polymer based electroluminescent devices, interface injection and carrier range, are investigated. It is established that the ITO/PPV contact is capable of sustaining dark current under trap-free space-charge-limited (TFSCL) conditions into a hole transporting TPD:PC layer. TFSCL currents are not observed in devices without the PPV layer. Upon increasing the thickness of the PPV layer a deviation from the TFSCL regime is observed which is attributed to trapping of the injected holes within PPV. These observations suggest a novel method for estimating the trapping Mobility-lifetime product μτ for holes in PPV. By this means we estimate μτ ∼ 10−9 cm2/V.

Multilayer thin film heterostrutuctures comprised of alternating layers of a poly (phenylene vinylene) (PPV) precursor and various polyanions were fabricated using a new self-assembly technique. Thermal treatment of these films produced multilayers of the fully conjugated form of PPV. Alternating Multilayers fabricated with inert polyanions such as sulfonated polystyrene exhibited a very strong photoluminescence whereas alternating multilayers fabricated with electron acceptor polyanions such as sulfonated C?O and poly (thiophene acetic acid) displayed a highly quenched luminescence. This latter behavior suggests that self-assembled Multilayers can be used to examine photoinduced charge transfer interactions between PPV and various electron acceptors.

Orientation ordered high-Tc oxide films of Y1Ba2Cu3O7 were prepared by molecular beam epitaxy on SrTiO3 substrates. A combination of effusion cells and e-beam evaporators was used with the addition of an oxygen jet. The superconducting phase is formed by further O2 anneal at temperatures ≥800° C. For SrTiO3 (100), the Y1Ba2Cu3O7 films grow in the orientation of either the c-axis or the a-axis perpendicular to the film plane. Films with predominant “c⊥” orientation exhibit a high degree of crystalline order with a rocking curve 0.3° wide. The Jc is about two times higher than those with the “a⊥” orientation of a comparable Tc (R=0). For a typical film of 9000Å thickness, a Tc (R=O) of 87K, and a Jc of 7 × 104 A/cm2 at 77K were reproducibly achieved. For SrTiO3 (110), X-ray showed twinning of (110) and (103) orientations in Y1Ba2Cu3O7, thus precluding the observation of anisotropy expected for the in-plane axes of [001] and [110].

Boron diffusion profiles in single crystal silicon from highly doped polysilicon sources have been measured using SIMS after diffusion at 950°C for various times. These data have been analyzed to determine D(c) of boron in the single crystal. It is ncrmally assumed that at high boron concentrations D increases linearly with concentration. However, the shape of these profiles indicates that for a polysilicon source, this behavior does not appear to hold. Using Bolzmann-Matano analysis, D(c) was found to be insensitive to boron concentrations above 3.0E19 atoms/cm3. The results of this analysis were confirmed by using them as input to a diffusion simulation computer program and excellent agreement with the experimental profiles was obtained. The value of D was found to be unusually high at all concentrations in the single crystal and increased almost linearly with the doping level of the polysilicon. The effect of the furnace ramp-down cycle on the profiles near the crystal surface have also been investigated.