Automated Tour Design in the Saturnian System

Future missions to Enceladus would benefit from multi-moon tours that leverage V-infinity on resonant orbits to progressively transfer between moons. Such "resonance family hopping" trajectories present a vast search space for global optimization due to the different combinations of available resonances and flyby speeds. The proposed multi-objective tour design algorithm optimizes entire moon tours from Titan to Enceladus via grid-based dynamic programming, in which the computation time is significantly reduced by utilizing a database of V-infinity-leveraging transfers. The result unveils a complete trade space of the moon tour design to Enceladus in a tractable computation time and global optimality.Comment: 19 pages, 11 figures, 8 table

Preventing Voltage-dependent Gating of Anthrax Toxin Channels Using Engineered Disulfides

The channel-forming component of anthrax toxin, (PA63)7, is a heptameric water-soluble protein at neutral pH, but under acidic conditions it spontaneously inserts into lipid bilayers to form a 14-stranded β-barrel ion-conducting channel. This channel plays a vital role in anthrax pathogenesis because it serves as a conduit for the membrane translocation of the two enzymatic components of anthrax toxin, lethal factor and edema factor. Anthrax channels open and close in response to changes in transmembrane voltage, a property shared by several other pore-forming toxins. We have discovered an unexpected phenomenon in cysteine-substituted channels that provides a window into this gating process: their normal voltage-dependent gating can be abolished by reaction with methanethiosulfonate (MTS) reagents or exposure to oxidizing conditions. Remarkably, this perturbation is seen with cysteines substituted at sites all along the ∼100 Å length of the channel's β-barrel. In contrast, reaction with N-ethylmaleimide, a thiol-reactive compound that does not form a mixed disulfide, does not affect gating at any of the sites tested. These findings, coupled with our biochemical detection of dimers, have led us to conclude that MTS reagents are catalyzing the formation of intersubunit disulfide bonds that lock channels in a conducting state, and that voltage gating requires a conformational change that involves the entire β-barrel

Pig production feeding and management of the brood sow and litter

Successful pork production depends first upon selection of good breeding stock. The breeding stock selected should have the inherent ability to produce and nurse a large litter that will use feed efficiently. Equally important are proper feeding and management of the brood sow and her litter. It is a good plan to separate the gilts from the fattening hogs at 4 to 5 months of age and feed them a growing ration. Whole oats or a mixture of one-half oats and barley or wheat coarsely ground, self-fed, constitute a good foundation for a ration. Enough corn should be fed, probably a couple of ears daily, to each gilt to keep her gaining. One-half gallon of skimmilk daily or 1/2 pound of protein concentrate will furnish sufficient protein for one gilt in addition to what she obtains from grain and pasture. (The protein concentrate may be hand-fed or mixed with the grain on the basis of 5 pounds to each 100 pounds of grain.

Phylogenetic Origins and Age-Based Proportions of Malacho (Elops smithi) Relative to Ladyfish (Elops saurus): Species on the Move in the Western Gulf of Mexico

Two species of ladyfish occur in the Gulf of Mexico (GOM), Elops saurus and Elops smithi, that are morphologically indistinguishable except for vertebral counts but can also be identified by mitochondrial DNA haplotypes. Here we expand on previous work, most of which has occurred in Florida, and examine the demography, phylogenetics, geographic distribution, and age—structure of ladyfishes in Texas estuaries. Fishery—independent gill net data demonstrated that ladyfishes increase in abundance from north to south along the Texas coast. The abundance of ladyfishes also increased in Texas waters from 1982–2021, which coincides with recent trends of warmer winters. Genetic data confirmed that both E. saurus and E. smithi occur in Texas waters; however, E. smithi was far less common. Contrary to previous research, we observed higher levels of genetic diversity in E. saurus due to larger sample size and thorough sampling of the western portion of its geographic range. Phylogenetic analysis supported the existence of E. saurus as a distinct species but indicated that E. smithi may be paraphyletic with other species of Elops. Otolith analysis showed that the ages of E. saurus and E. smithi ranged from 0–3 years. The lack of individuals \u3e age—3 suggests that ladyfishes migrate to the offshore GOM at age 3 and do not return to coastal areas. This study enhances knowledge of the biology of ladyfishes in inshore waters of the northwestern GOM. Future management would benefit from expanding this research to the entire geographic range of the genus Elops

Archaeological Investigations Under Texas Antiquities Permit No. 4925 for the Texas Department of Transportation, Fort Bend, Galveston, and Harris Counties, Texas

In May 2008, PBSJ (now Atkins North America, Inc.), was contracted by the Texas Department of Transportation (TxDOT), to conduct archaeological impact evaluations and surveys for the Houston and Beaumont Districts under Contract 578-XX-SA004. This contract was for on-demand services, with specific work defined by individual work authorizations. However, all investigations were subsumed under a single Texas Antiquities Permit (No. 4925) for the contract, with Michael Nash serving as Principal Investigator during fieldwork. Four work authorizations were issued, but only three surveys were conducted due to a refusal of Right-of-Entry on one job. All fieldwork was conducted between October 2008 and April 2010. Projects were located in Fort Bend, Galveston, and Harris Counties. Following completion of the fieldwork and the majority of reporting, the permit was transferred to TxDOT, with James T. Abbott serving as Principal Investigator. Final preparation of this report was performed by Abbott, based upon a draft provided by Atkins. WA 1 authorized survey of a planned detention pond adjacent to Farm to Market Road (FM) 2978, between 0.065 and 0.145 south of Bogs Road in Harris County. An intensive survey of the 4.13-acre site was conducted on October 2, 2008 by Rebecca Sager and Ephriam McDowell. Four shovel tests were excavated during the survey, all of which were negative for cultural material. No cultural resources were encountered during the survey, and Atkins recommended that no further investigations were warranted and the project receive archaeological clearance. WA 2 authorized a survey prior to construction of beach stabilization structures along a 4.7- mile length of SH 87 in Galveston County. The archaeological project area designated in the scope of work consisted of 35 acres of existing right-of-way (ROW) within an overall 70.0 acres of existing ROW. A visual inspection of the project area and excavation of one shovel test was conducted on February 4 and 5, 2009, by Damon Burden and Joe Craig. No cultural resources encountered during the survey, the survey area was found to be heavily disturbed, and Atkins recommended that no further investigations were warranted. WA 3 was a proposed realignment of Conroe-Hufsmith Road at FM 2978 in Montgomery County. The project would have required 2.0 acres of new ROW, and the APE would have included the new ROW as well as any existing ROW along the project length. However, permission to conduct archaeological investigations was denied by the affected landowner, and the Work Authorization was cancelled. WA 4 was issued for an intensive survey in advance of improvements to FM 1464 at New Home Cemetery in Fort Bend County. An initial survey was conducted at the location, but due to a contractual dispute between Atkins and TxDOT regarding the scope of services, not all work associated with the project was completed by Atkins. This report describes the work that was completed under this permit

Magnetour: Surfing Planetary Systems on Electromagnetic and Multi-Body Gravity Fields

In this NIAC Phase One study, we propose a new mission concept, named Magnetour, to facilitate the exploration of outer planet systems and address both power and propulsion challenges. Our approach would enable a single spacecraft to orbit and travel between multiple moons of an outer planet, with no propellant required. Our approach would enable a single spacecraft to orbit and travel between multiple moons of an outer planet, with no propellant nor onboard power source required. To achieve this free-lunch _Grand Tour', we exploit the unexplored combination of magnetic and multi-body gravitational fields of planetary systems, with a unique focus on using a bare tether for power and propulsion. The main objective of the study is to develop this conceptually novel mission architecture, explore its design space, and investigate its feasibility and applicability to enhance the exploration of planetary systems within a 10-year timeframe. Propellantless propulsion technology offers enormous potential to transform the way NASA conducts outer planet missions. We hope to demonstrate that our free-lunch tour concept can replace heavy, costly, traditional chemical-based missions and can open up a new variety of trajectories around outer planets. Leveraging the powerful magnetic and multi-body gravity fields of planetary systems to travel freely among planetary moons would allow for long-term missions and provide unique scientific capabilities and flagship-class science for a fraction of the mass and cost of traditional concepts. New mission design techniques are needed to fully exploit the potential of this new concept.This final report contains the results and findings of the Phase One study, and is organized as follows. First, an overview of the Magnetour mission concept is presented. Then, the research methodology adopted for this Phase One study is described, followed by a brief outline of the main findings and their correspondence with the original Phase One task plan. Next, an overview of the environment of outer planets is provided, including magnetosphere, radiation belt and planetary moons. Then performance of electrodynamic tethers is assessed, as well as other electromagnetic systems. A method to exploit multi-body dynamics is given next. These analyses allow us to carry out a Jovian mission design to gain insight in the benefits of Magnetour. In addition, a spacecraft configuration is presented that fully incorporates the tether in the design. Finally technology roadmap considerations are discussed

Endoscopic capacity in West Africa

Background: Levels of endoscopic demand and capacity in West Africa are unclear.Objectives: This paper aims to: 1. describe the current labor and endoscopic capacity, 2. quantify the impact of a mixed-methods endoscopy course on healthcare professionals in West Africa, and 3. quantify the types of diagnoses encountered.Methods: In a three-day course, healthcare professionals were surveyed on endoscopic resources and capacity and were taught through active observation of live cases, case discussion, simulator experience and didactics. Before and after didactics, multiplechoice exams as well as questionnaires were administered to assess for course efficacy. Also, a case series of 23 patients needing upper GI endoscopy was done.Results: In surveying physicians, less than half had resources to perform an EGD and none could perform an ERCP, while waiting time for emergency endoscopy in urban populations was at least one day. In assessing improvement in medical knowledge among participants after didactics, objective data paired with subjective responses was more useful than either alone. Of 23 patients who received endoscopy, 7 required endoscopic intervention with 6 having gastric or esophageal varices. Currently the endoscopic capacity in West Africa is not sufficient. A formal GI course with simulation and didactics improves gastrointestinal knowledge amongst participants.Keywords: Endoscopic capacity, endoscopic demand, West Africa, training cours

Longitudinal Analysis of Memory B and T Cell Responses to Dengue Virus in a 5-Year Prospective Cohort Study in Thailand

Prior exposure to dengue virus (DENV) has a profound impact on the outcome of infection, which varies according to the interval between infections. Antibodies secreted by B cells and cytokines secreted by T cells are thought to contribute both to protective immunity against DENV and the pathogenesis of dengue disease. We analyzed peripheral blood mononuclear cells (PBMC) collected from Thai children over a 5-year prospective cohort study to define the dynamics of DENV-specific memory B and T cell responses and the impact of symptomatic or subclinical DENV infections. To measure B cell responses, PBMC were stimulated with IL-2 plus R848 and culture supernatants were tested for DENV-binding antibodies by ELISA. To measure T cell responses, PBMC were stimulated in dual-color ELISPOT assays with overlapping peptide pools of structural and non-structural proteins from the four DENV types. B cell responses were low to one or more DENV types prior to symptomatic infection and increased with reactivity to all four types after infection. Subjects who had a subclinical infection or who did not experience a DENV infection during the study period showed strong memory B cell responses to all four DENV types. T cell responses to DENV peptides demonstrated a cytokine hierarchy of IFN-γ \u3e IL-2 \u3e IFN-γ/IL-2. T cell responses were low or absent prior to secondary infections. The trends in T cell responses to DENV peptides over 3 year post-infection were highly variable, but subjects who had experienced a secondary DENV1 infection showed higher cytokine responses compared to subjects who had experienced a secondary DENV2 or subclinical infection. The longitudinal nature of our study demonstrates persistent memory B cell responses over years and a lasting but variable impact of secondary DENV infection on DENV-specific T cell responses