5,590 research outputs found

    Insect Resistance Management for Bt Corn : An Assessment of Community Refuge Schemes

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    Because of Bt corn's efficacy in controlling European corn borer, farmers are required to implement an insect resistance management (IRM) program that constrains each farmer to plant no more than 80% of the farm s corn to Bt varieties. This refuge must be planted within a half-mile of Bt corn and must be contained on the same farm. Community refuge schemes, those which allow the refuge area to be planted on a neighboring farm, have been proposed. In this analysis, we estimate the potential gains to all farms in the community in two representative locations: Pennsylvania and Iowa. The results of a decision analysis model show that the potential gains are very small; the greatest is only 652overa2000acrecommunity(652 over a 2000-acre community (0.33 per acre). This gain would almost certainly be offset by the costs of developing such a community.Includes bibliographical reference

    Validating constraints with partial information: research overview

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    We are interested in the problem of validating the consistency of integrity constraints when data is modified. In particular, we consider how constraints can be checked with only "partial information". Partial information may include: (1) the constraint specifications only, (2) the constraint specifications and the modified data, or (3) the constraint specifications, the modified data, and portions ofthe existing data. Methods for constraint checking with partía! ínformation can be much more efficient than traditional constraint checking methods ( e.g. because work is done at compile time, or because less data is accessed). Partial information methods also enable constraint checking in scenarios where tradítíonal constraint checking methods fail (e.g. in distributed environments where not all data is accessible). We explain how existing methods and results for query containment and for independeñce can be applied to problems (1) and (2) above, and we give an overview of our research into problem (3)

    Bioavailability of Cadmium in Inexpensive Jewelry

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    Objectives: We evaluated the bioavailability of Cd in 86 components of 57 jewelry items found to contain high levels of Cd (> 10,000 ppm) by X-ray fluorescence (XRF), using extractions that simulate mouthing or swallowing of jewelry items

    The Design and Operation of The Keck Observatory Archive

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    The Infrared Processing and Analysis Center (IPAC) and the W. M. Keck Observatory (WMKO) operate an archive for the Keck Observatory. At the end of 2013, KOA completed the ingestion of data from all eight active observatory instruments. KOA will continue to ingest all newly obtained observations, at an anticipated volume of 4 TB per year. The data are transmitted electronically from WMKO to IPAC for storage and curation. Access to data is governed by a data use policy, and approximately two-thirds of the data in the archive are public.Comment: 12 pages, 4 figs, 4 tables. Presented at Software and Cyberinfrastructure for Astronomy III, SPIE Astronomical Telescopes + Instrumentation 2014. June 2014, Montreal, Canad

    Use of a Pressure Guidewire to Assess Pulmonary Artery Band Adequacy in the Hybrid Stage I Procedure for High‐risk Neonates with Hypoplastic Left Heart Syndrome and Variants

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    Objective The hybrid stage I procedure is an alternative palliative strategy for patients with hypoplastic left heart syndrome who traditionally have undergone the N orwood operation. At our institution, the hybrid stage I procedure is employed only for patients with high operative risk. Our objective was to describe our use of a pressure guidewire during the hybrid stage I procedure to assess quantitatively pulmonary artery band adequacy. Design After reviewing the charts on all high‐risk patients who underwent a hybrid stage I procedure at our institution, we compared two groups of patients: those who underwent the standard hybrid stage I palliation (standard cohort) and those with pressure wire‐facilitated assessment of distal branch pulmonary artery pressure (pressure wire cohort) to evaluate the impact of pressure guidewire use on procedural risk, radiation time, patient outcomes, and need for reoperation for pulmonary artery band adjustment. Results The pressure guidewire was used in 8 of 14 patients at the time of hybrid stage I procedure and was successful and without complication in all attempts. In the standard cohort, 67% of patients needed reoperation for pulmonary artery band adjustment, compared to 12.5% of patients in the pressure wire cohort ( P =.09). Procedure time, radiation exposure, and survival to hospital discharge were not different between groups. Conclusions This novel use of a pressure guidewire to assess quantitatively pulmonary artery band adequacy at the time of placement is feasible, safe and may decrease the need for reoperation for pulmonary artery band adjustment.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97511/1/chd12005.pd

    Expression of neurogenin3 reveals an islet cell precursor population in the pancreas

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    Differentiation of early gut endoderm cells into the endocrine cells forming the pancreatic islets of Langerhans depends on a cascade of gene activation events controlled by transcription factors including the basic helix-loop-helix (bHLH) proteins. To delineate this cascade, we began by establishing the position of neurogenin3, a bHLH factor found in the pancreas during fetal development. We detect neurogenin3 immunoreactivity transiently in scattered ductal cells in the fetal mouse pancreas, peaking at embryonic day 15.5. Although not detected in cells expressing islet hormones or the islet transcription factors Isl1, Brn4, Pax6 or PDX1, neurogenin3 is detected along with early islet differentiation factors Nkx6.1 and Nkx2.2, establishing that it is expressed in immature cells in the islet lineage. Analysis of transcription factor-deficient mice demonstrates that neurogenin3 expression is not dependent on neuroD1/BETA2, Mash1, Nkx2.2, Nkx6.1, or Pax6. Furthermore, early expression of neurogenin3 under control of the Pdx1 promoter is alone sufficient to drive early and ectopic differentiation of islet cells, a capability shared by the pancreatic bHLH factor, neuroD1/BETA2, but not by the muscle bHLH factor, MyoD. However, the islet cells produced in these transgenic experiments are overwhelmingly α cells, suggesting that factors other than the bHLH factors are required to deviate from a default α cell fate. These data support a model in which neurogenin3 acts upstream of other islet differentiation factors, initiating the differentiation of endocrine cells, but switching off prior to final differentiation. The ability to uniquely identify islet cell precursors by neurogenin3 expression allows us to determine the position of other islet transcription factors in the differentiation cascade and to propose a map for the islet cell differentiation pathway

    Small Spacecraft Sample Return Mission Concept to Support Gateway and Lunar Science

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    Sustaining long-term presence at the Moon will likely require innovative and cost-effective approaches for frequent and affordable payload return. NASA Ames Research Center and the Deep Space Logistics team at Kennedy Space Center (which manages the Gateway Logistics Services missions) have investigated the development of a small spacecraft-based sample return capability to complement the limited sample return capacity available with the early Orion missions. The goal is to demonstrate a cost-effective capability as part of an early Deep Space Logistics mission and provide up to 10 kg (~ 4 L volume) of scientific payload returned from the Gateway. The mission concept envisions the progressive addition of sample return capabilities, including returning temperature- and acceleration- sensitive payloads, and evolution into a commercially provided service, similar to existing International Space Station payload return logistics. An overview of payload science and technology use cases and small spacecraft mission concepts will be presented to engage scientists, payload developers and mission planners who are considering Lunar exploration activities that will require the return of high-value samples from the Gateway and/or the lunar surface

    HIV Testing Policies in Florida

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    To combat the HIV/AIDS epidemic, strong policies that promote HIV testing are a primary mechanism for helping public health officials to understand the populations at risk, informing prevention initiatives, and linking infected individuals to the timely care they need. This paper describes HIV testing policies with the goal of improving early diagnosis and treatment of Floridians

    A new and unusual LBV-like outburst from a Wolf–Rayet star in the outskirts of M33

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    MCA-1B (also called UIT003) is a luminous hot star in the western outskirts of M33, classified over 20 yr ago with a spectral type of Ofpe/WN9 and identified then as a candidate luminous blue variable (LBV). Palomar Transient Factory data reveal that this star brightened in 2010, with a light curve resembling that of the classic LBV star AF And in M31. Other Ofpe/WN9 stars have erupted as LBVs, but MCA-1B was unusual because it remained hot. It showed a WN-type spectrum throughout its eruption, whereas LBVs usually get much cooler. MCA-1B showed an almost four-fold increase in bolometric luminosity and a doubling of its radius, but its temperature stayed ≳29 kK. As it faded, it shifted to even hotter temperatures, exhibiting a WN7/WN8-type spectrum, and doubling its wind speed. MCA-1B is reminiscent of some supernova impostors, and its location resembles the isolated environment of SN 2009ip. It is most similar to HD 5980 (in the Small Magellanic Cloud) and GR 290 (also in M33). Whereas these two LBVs exhibited B-type spectra in eruption, MCA-1B is the first clear case where a Wolf–Rayet (WR) spectrum persisted at all times. Together, MCA-1B, HD 5980, and GR 290 constitute a class of WN-type LBVs, distinct from S Doradus LBVs. They are most interesting in the context of LBVs at low metallicity, a possible post-LBV/WR transition in binaries, and as likely Type Ibn supernova progenitors
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