238 research outputs found
Enhanced Eshelby twist on thin wurtzite InP nanowires and measurement of local crystal rotation
We have performed a detailed study of the lattice distortions of InP wurtzite nanowires containing an axial screw dislocation. Eshelby predicted that this kind of system should show a crystal rotation due to the dislocation induced torque. We have measured the twisting rate and the dislocation Burgers vector on individual wires, revealing that nanowires with a 10-nm radius have a twist up to 100% larger than estimated from elasticity theory. The strain induced by the deformation has a Mexican-hat-like geometry, which may create a tube-like potential well for carriers
Integrating modes of policy analysis and strategic management practice : requisite elements and dilemmas
There is a need to bring methods to bear on public problems that are inclusive, analytic, and quick. This paper describes the efforts of three pairs of academics working from three different though complementary theoretical foundations and intervention backgrounds (i.e., ways of working) who set out together to meet this challenge. Each of the three pairs had conducted dozens of interventions that had been regarded as successful or very successful by the client groups in dealing with complex policy and strategic problems. One approach focused on leadership issues and stakeholders, another on negotiating competitive strategic intent with attention to stakeholder responses, and the third on analysis of feedback ramifications in developing policies. This paper describes the 10 year longitudinal research project designed to address the above challenge. The important outcomes are reported: the requisite elements of a general integrated approach and the enduring puzzles and tensions that arose from seeking to design a wide-ranging multi-method approach
Impacts of dielectric screening on the luminescence of monolayer WSe
Single layers of transition metal dichalcogenides, such as WSe have
gathered increasing attention due to their intense electron-hole interactions,
being considered promising candidates for developing novel optical
applications. Within the few-layer regime, these systems become highly
sensitive to the surrounding environment, enabling the possibility of using a
proper substrate to tune desired aspects of these atomically-thin
semiconductors. In this scenario, the dielectric environment provided by the
substrates exerts significant influence on electronic and optical properties of
these layered materials, affecting the electronic band-gap and the exciton
binding energy. However, the corresponding effect on the luminescence of
transition metal dichalcogenides is still under discussion. To elucidate these
impacts, we used a broad set of materials as substrates for single-layers of
WSe, enabling the observation of these effects over a wide range of
electrical permittivities. Our results demonstrate that an increasing
permittivity induces a systematic red-shift of the optical band-gap of WSe,
intrinsically related to a considerable reduction of the luminescence
intensity. Moreover, we annealed the samples to ensure a tight coupling between
WSeand its substrates, reducing the effect of undesired adsorbates trapped
in the interface. Ultimately, our findings reveal how critical the annealing
temperature can be, indicating that above a certain threshold, the heating
treatment can induce adverse impacts on the luminescence. Furthermore, our
conclusions highlight the influence the dielectric properties of the substrate
have on the luminescence of WSe, showing that a low electrical permittivity
favours preserving the native properties of the adjacent monolayerComment: 16 pages, 8 figure
Post-emergence selectivity of metribuzin to carrot.
The objective of this study was to evaluate the selectivity of the herbicide metribuzin to carrot plants as a function of genotype, dose, and plant growth stage at the time of application. Two experiments were carried out, one in a greenhouse and another in the field
Tumor biopsy and patient enrollment in clinical trials for advanced hepatocellular carcinoma
Tumor biopsies may help to reliably distinguish hepatocellular carcinoma (HCC) from other tumors, mostly cholangiocarcinoma as well as to identify the patient populations who most benefit from target-driven HCC treatments, in order to improve the success rate of experimental therapies. Clarifying tumor biology may also lead to identify biomarkers with prognostic role and/or enabling to predict response or resistance to therapies. Recently, clinical trials have more efficiently included biomarker endpoints and increasingly collected tumor tissue from enrolled patients. Due to their frail status and sometimes fast-progressing disease, the performance status of patients with HCC progressing on first-line therapy can deteriorate quickly, preventing their enrollment in clinical trials. However, the challenge of identifying the proper patient at the proper time can be overcome by periodic inter-department meetings involving the key specialists taking care of HCC patients, and solid networks between research centers and referring institutions. An early planned biopsy would also facilitate timely inclusion of patients in biology-driven clinical trials. Ultimately, institution of multidisciplinary teams can optimize treatment choice, biopsy timing, and quick enrollment of patients in clinical trials, before their performance status deteriorates
- âŠ