Inflaton potential reconstruction in the braneworld scenario

We consider inflaton potential reconstruction in the context of the simplest braneworld scenario, where both the Friedmann equation and the form of scalar and tensor perturbations are modified at high energies. We derive the reconstruction equations, and analyze them analytically in the high-energy limit and numerically for the general case. As previously shown by Huey and Lidsey, the consistency equation between scalar and tensor perturbations is unchanged in the braneworld scenario. We show that this leads to a perfect degeneracy in reconstruction, whereby a different viable potential can be obtained for any value of the brane tension $\lambda$. Accordingly, the initial perturbations alone cannot be used to distinguish the braneworld scenario from the usual Einstein gravity case.Comment: 5 pages RevTeX4 file with four figures incorporated; minor addition to discussio

Gravitino production in the warm inflationary scenario

We estimate the production of gravitinos during and after the end of a period of warm inflation, a model in which radiation is produced continuously as the field rolls down the potential producing dissipation. We find that gravitino production is efficient for models in the strong dissipation regime, with the result that standard nucleosynthesis is disrupted unless the magnitude of the inflaton potential is very small. Combining this with the constraint from the thermal production of adiabatic density perturbations we find the dissipation rate must be extraordinarily strong, or that the potential is very flat.Comment: 7 pages, 3 figures, submitted to Phys Rev

Linear feedback stabilization of a dispersively monitored qubit

The state of a continuously monitored qubit evolves stochastically, exhibiting competition between coherent Hamiltonian dynamics and diffusive partial collapse dynamics that follow the measurement record. We couple these distinct types of dynamics together by linearly feeding the collected record for dispersive energy measurements directly back into a coherent Rabi drive amplitude. Such feedback turns the competition cooperative, and effectively stabilizes the qubit state near a target state. We derive the conditions for obtaining such dispersive state stabilization and verify the stabilization conditions numerically. We include common experimental nonidealities, such as energy decay, environmental dephasing, detector efficiency, and feedback delay, and show that the feedback delay has the most significant negative effect on the feedback protocol. Setting the measurement collapse timescale to be long compared to the feedback delay yields the best stabilization.Comment: 16 pages, 7 figure

Climate change and Pacific Island food systems

Climate change in Pacific Island countries and territories (PICTs) is projected to have significant impacts, including rising sea-levels, more violent tropical cyclones and droughts. Fish stocks in the tropical regions of the Pacific are expected to be directly affected by any changes that may occur in the ocean’s ecosystem. The four alternative scenarios of the future of the Pacific food systems that are reported in this booklet provide important insights into the different dimensions of the food system, including fisheries and forests, trade, affordability and consumption, and public health. The scenarios offer essential information for policy-makers, in order for them to be able to test and take steps toward developing policies that enhance resilience and strengthen adaptation to climate change among fishers and farmers in the Pacific region

Quantitative characterization of viscoelastic behavior in tissue-mimicking phantoms and ex vivo animal tissues.

Viscoelasticity of soft tissue is often related to pathology, and therefore, has become an important diagnostic indicator in the clinical assessment of suspect tissue. Surgeons, particularly within head and neck subsites, typically use palpation techniques for intra-operative tumor detection. This detection method, however, is highly subjective and often fails to detect small or deep abnormalities. Vibroacoustography (VA) and similar methods have previously been used to distinguish tissue with high-contrast, but a firm understanding of the main contrast mechanism has yet to be verified. The contributions of tissue mechanical properties in VA images have been difficult to verify given the limited literature on viscoelastic properties of various normal and diseased tissue. This paper aims to investigate viscoelasticity theory and present a detailed description of viscoelastic experimental results obtained in tissue-mimicking phantoms (TMPs) and ex vivo tissues to verify the main contrast mechanism in VA and similar imaging modalities. A spherical-tip micro-indentation technique was employed with the Hertzian model to acquire absolute, quantitative, point measurements of the elastic modulus (E), long term shear modulus (η), and time constant (τ) in homogeneous TMPs and ex vivo tissue in rat liver and porcine liver and gallbladder. Viscoelastic differences observed between porcine liver and gallbladder tissue suggest that imaging modalities which utilize the mechanical properties of tissue as a primary contrast mechanism can potentially be used to quantitatively differentiate between proximate organs in a clinical setting. These results may facilitate more accurate tissue modeling and add information not currently available to the field of systems characterization and biomedical research

Effect of Lean Processes on Surgical Wait Times and Efficiency in a Tertiary Care Veterans Affairs Medical Center

Importance There are an increasing number of veterans in the United States, and the current delay and wait times prevent Veterans Affairs institutions from fully meeting the needs of current and former service members. Concrete strategies to improve throughput at these facilities have been sparse. Objective To identify whether lean processes can be used to improve wait times for surgical procedures in Veterans Affairs hospitals. Design, Setting, and Participants Databases in the Veterans Integrated Service Network 11 Data Warehouse, Veterans Health Administration Support Service Center, and Veterans Information Systems and Technology Architecture/Dynamic Host Configuration Protocol were queried to assess changes in wait times for elective general surgical procedures and clinical volume before, during, and after implementation of lean processes over 3 fiscal years (FYs) at a tertiary care Veterans Affairs medical center. All patients evaluated by the general surgery department through outpatient clinics, clinical video teleconferencing, and e-consultations from October 2011 through September 2014 were included. Patients evaluated through the emergency department or as inpatient consults were excluded. Exposures The surgery service and systems redesign service held a value stream analysis in FY 2013, culminating in multiple rapid process improvement workshops. Multidisciplinary teams identified systemic inefficiencies and strategies to improve interdepartmental and patient communication to reduce canceled consultations and cases, diagnostic rework, and no-shows. High-priority triage with enhanced operating room flexibility was instituted to reduce scheduling wait times. General surgery department pilot projects were then implemented mid-FY 2013. Main Outcomes and Measures Planned outcome measures included wait time, clinic and telehealth volume, number of no-shows, and operative volume. Paired t tests were used to identify differences in outcome measures after the institution of reforms. Results Following rapid process improvement workshop project rollouts, mean (SD) patient wait times for elective general surgical procedures decreased from 33.4 (8.3) days in FY 2012 to 26.0 (9.5) days in FY 2013 (P = .02). In FY 2014, mean (SD) wait times were half the value of the previous FY at 12.0 (2.1) days (P = .07). This was a 3-fold decrease from wait times in FY 2012 (P = .02). Operative volume increased from 931 patients in FY 2012 to 1090 in FY 2013 and 1072 in FY 2014. Combined clinic, telehealth, and e-consultation encounters increased from 3131 in FY 2012 to 3460 in FY 2013 and 3517 in FY 2014, while the number of no-shows decreased from 366 in FY 2012 to 227 in FY 2014 (P = .02). Conclusions and Relevance Improvement in the overall surgical patient experience can stem from multidisciplinary collaboration among systems redesign personnel, clinicians, and surgical staff to reduce systemic inefficiencies. Monitoring and follow-up of system efficiency measures and the employment of lean practices and process improvements can have positive short- and long-term effects on wait times, clinical throughput, and patient care and satisfaction