Estimating the reproductive number, total outbreak size, and reporting rates for Zika epidemics in South and Central America

As South and Central American countries prepare for increased birth defects from Zika virus outbreaks and plan for mitigation strategies to minimize ongoing and future outbreaks, understanding important characteristics of Zika outbreaks and how they vary across regions is a challenging and important problem. We developed a mathematical model for the 2015 Zika virus outbreak dynamics in Colombia, El Salvador, and Suriname. We fit the model to publicly available data provided by the Pan American Health Organization, using Approximate Bayesian Computation to estimate parameter distributions and provide uncertainty quantification. An important model input is the at-risk susceptible population, which can vary with a number of factors including climate, elevation, population density, and socio-economic status. We informed this initial condition using the highest historically reported dengue incidence modified by the probable dengue reporting rates in the chosen countries. The model indicated that a country-level analysis was not appropriate for Colombia. We then estimated the basic reproduction number, or the expected number of new human infections arising from a single infected human, to range between 4 and 6 for El Salvador and Suriname with a median of 4.3 and 5.3, respectively. We estimated the reporting rate to be around 16% in El Salvador and 18% in Suriname with estimated total outbreak sizes of 73,395 and 21,647 people, respectively. The uncertainty in parameter estimates highlights a need for research and data collection that will better constrain parameter ranges.Comment: 35 pages, 16 figure

Performance and Fundamental Processes at Low Energy in a Two-Phase Liquid Xenon Dark Matter Detector

We extend the study of the performance of a prototype two-phase liquid xenon WIMP dark matter detector to recoil energies below 20 keV. We demonstrate a new method for obtaining the best estimate of the energies of events using a calibrated sum of charge and light signals and introduce the corresponding discrimination parameter, giving its mean value at 4 kV/cm for electron and nuclear recoils up to 300 and 100 keV, respectively. We show that fluctuations in recombination limit discrimination for most energies, and reveal an improvement in discrimination below 20 keV due to a surprising increase in ionization yield for low energy electron recoils. This improvement is crucial for a high-sensitivity dark matter search.Comment: 4 pages, 6 figures, submitted to DM06 conference proceedings in Nucl Phys

Scintillation Pulse Shape Discrimination in a Two-Phase Xenon Time Projection Chamber

The energy and electric field dependence of pulse shape discrimination in liquid xenon have been measured in a 10 gm two-phase xenon time projection chamber. We have demonstrated the use of the pulse shape and charge-to-light ratio simultaneously to obtain a leakage below that achievable by either discriminant alone. A Monte Carlo is used to show that the dominant fluctuation in the pulse shape quantity is statistical in nature, and project the performance of these techniques in larger detectors. Although the performance is generally weak at low energies relevant to elastic WIMP recoil searches, the pulse shape can be used in probing for higher energy inelastic WIMP recoils.Comment: 7 pages, 11 figure

HARVEST TIME AND SUGAR COMPOSITION OF EARLY AND LATE CULTIVATED STAPLE-TYPE SWEET POTATO (Ipomoea batatas (L) Lam) CULTIVARS ON THE JOS PLATEAU, NIGERIA

Sweet potato (Ipomoea batatas (L) Lam) is a Staple – type food source on the Jos Plateau. A study was carried out to assay for its carbohydrate and soluble sugars at different harvest times. The improved varieties CIP4400168, Ex-Igbariam, Tanzania, TIS 8164 and TIS 87/0087 and local landraces, Jandankali I, Jandankali II, Jandankali III local varieties were collected from farmers on the Jos Plateau. These were planted within Jos, harvested after 4 and 6 months, processed into chips of 1 x 1 x 6mm dimension, dried in Air ovendrier, milled and sieved to fine flours. One gram (1.0g) of the flour was dissolved in 50ml of distilled water, shaken in 250ml flask to extract its constituents, tested for carbohydrate and soluble sugars qualitatively and quantitatively for glucose, fructose, maltose and sucrose.&nbsp

Repeated Restraint and Sampling Results in Reduced Corticosterone Levels in Developing and Adult Captive American Kestrels (Falco sparverius)

Presents a study which evaluated the effects of repeated restraint on the ability of postnatally developing chicks and adults to respond to a repeated standardized stressor of capture and handling in a semialtricial raptorial species, the American kestrel. Blood sampling and general procedure; Corticosterone radioimmunoassay analysis; Corticosterone levels in postnatally developing chicks and adults

Background discrimination capabilities of a heat and ionization germanium cryogenic detector

The discrimination capabilities of a 70 g heat and ionization Ge bolometer are studied. This first prototype has been used by the EDELWEISS Dark Matter experiment, installed in the Laboratoire Souterrain de Modane, for direct detection of WIMPs. Gamma and neutron calibrations demonstrate that this type of detector is able to reject more than 99.6% of the background while retaining 95% of the signal, provided that the background events distribution is not biased towards the surface of the Ge crystal. However, the 1.17 kg.day of data taken in a relatively important radioactive environment show an extra population slightly overlapping the signal. This background is likely due to interactions of low energy photons or electrons near the surface of the crystal, and is somewhat reduced by applying a higher charge-collecting inverse bias voltage (-6 V instead of -2 V) to the Ge diode. Despite this contamination, more than 98% of the background can be rejected while retaining 50% of the signal. This yields a conservative upper limit of 0.7 event.day^{-1}.kg^{-1}.keV^{-1}_{recoil} at 90% confidence level in the 15-45 keV recoil energy interval; the present sensitivity appears to be limited by the fast ambient neutrons. Upgrades in progress on the installation are summarized.Comment: Submitted to Astroparticle Physics, 14 page

ROT OF SEED POTATO (SOLANUM TUBEROSUM L.) TUBERS AFFECTED BY STORAGE CONDITIONS AND STORAGE DURATION IN JOS, PLATEAU STATE, NIGERIA

A study was carried out at the National Root Crops Research Institute (NRCRI), Potato Programme Kuru, Jos Plateau State, Nigeria (Longitude 08oE 47l, Latitude 09oN 441and 1,239 meters above sea level (msl)) during three seasons to investigate ‘the rot of potato (Solanum tuberosum L.) seed tubersas affected by storage conditions and storage duration.’ Five potato varieties (Nicola, Bertita, Diamant, BR63-18 and Roslin Ruaka) were stored for three durations (12, 24 and 32 weeks) in three kinds of stores (room temperature store (RTS), diffused light store (DLS) and air conditioned store (ACS). The experimental design used was completely randomized design in factorial combination of 5 potato varieties forming the main plots, three storage conditions and three storage durations constituting the split plots. There were 45 treatment combinations replicated 3 times. Weekly temperatures and relative humidity were recorded in each type of store.For percentage tuber rot, the result showed that all main effects were significant (P<0.05) except the main effect of variety and store type during season 2. All the varieties had similar percentage tuber rot except the variety Nicola which showed significantly lower tuber rot. RTS and DLS resulted in significantly higher tuber rot than the ACS. Tuber rot (%) was lowest at 24 weeks of storage in all the 3 seasons while 32 weeks of storage resulted in significantly higher rot than the other periods. All interactions were significant in the first cropping season, only the interaction of variety X storage duration was significant in the second cropping season, while inthe third cropping season, all interactions were significant except the interaction of store type X storage duration. For number of whole tubers left after storage, all the main effects and interactions were significant. Variety Nicola resulted in the highest number of whole tubers leftwhile Roslin Ruaka had the lowest tubers left in cropping seasons 1 and 2 and variety Diamant had lowest tubers left in cropping season 3. The number of tubers left decreased with storage period with the lowest number of tubers left after 32 weeks of storage. Tuber storage in ACS resulted in highest number of tubers left while RTS was lowest. The RTS and DLS characterized by higher temperature enhanced rot of tubers while the ACS with lower temperature reduced rot of tubers, it is therefore suggested that for prolong storage (8-9 months), the ACS should be use

Exclusion limits on the WIMP-nucleon cross-section from the Cryogenic Dark Matter Search

The Cryogenic Dark Matter Search (CDMS) employs low-temperature Ge and Si detectors to search for Weakly Interacting Massive Particles (WIMPs) via their elastic-scattering interactions with nuclei while discriminating against interactions of background particles. For recoil energies above 10 keV, events due to background photons are rejected with >99.9% efficiency, and surface events are rejected with >95% efficiency. The estimate of the background due to neutrons is based primarily on the observation of multiple-scatter events that should all be neutrons. Data selection is determined primarily by examining calibration data and vetoed events. Resulting efficiencies should be accurate to about 10%. Results of CDMS data from 1998 and 1999 with a relaxed fiducial-volume cut (resulting in 15.8 kg-days exposure on Ge) are consistent with an earlier analysis with a more restrictive fiducial-volume cut. Twenty-three WIMP candidate events are observed, but these events are consistent with a background from neutrons in all ways tested. Resulting limits on the spin-independent WIMP-nucleon elastic-scattering cross-section exclude unexplored parameter space for WIMPs with masses between 10-70 GeV c^{-2}. These limits border, but do not exclude, parameter space allowed by supersymmetry models and accelerator constraints. Results are compatible with some regions reported as allowed at 3-sigma by the annual-modulation measurement of the DAMA collaboration. However, under the assumptions of standard WIMP interactions and a standard halo, the results are incompatible with the DAMA most likely value at >99.9% CL, and are incompatible with the model-independent annual-modulation signal of DAMA at 99.99% CL in the asymptotic limit.Comment: 40 pages, 49 figures (4 in color), submitted to Phys. Rev. D; v.2:clarified conclusions, added content and references based on referee's and readers' comments; v.3: clarified introductory sections, added figure based on referee's comment