Advanced Gun System (AGS) Backfit

U.S. Navy, Naval Sea Systems Command and Program Executive Office SHIPS, PMS 500 DD X Progra

Structural loading of cross deck connections for trimaran vessels

CIVINS (Civilian Institutions) Thesis documentThis work investigates the fundamental relationships of wave loading on cross deck structures for trimaran vessels. In contrast with a monohull ship, trimaran vessels experience several possible structural loading cases including: longitudinal bending, transverse bending, torsional bending, spreading and squeezing of hulls, inner and outer hull slam pressures, wet deck slam pressures, loading from ship's motions, and whipping of slender hulls. This work investigates wave loading cases that result in transverse and torsional bending of the cross deck structure. The wave loading cases investigated include: side hull troughing and cresting in longitudinal waves, side hull torsion in longitudinal waves, and transverse hogging and sagging. For each of these load cases, a design load using a fully statistical sea state was derived using an analytical model of a trimaran represented by rigidly connected box barges. The design loadings with a reliability index of 5 for almost 500 trimaran configurations were calculated varying main hull length, side hull length, side hull transverse placement, and side hull longitudinal placement. The design loadings were curve fit to a fourth order polynomial in the three independent variables. The load predictions of the analytical box model of a trimaran were applied to a trimaran vessel with a realistic hull form using the finite element ship structural analysis program MAESTRO. Given the number of approximations and assumptions in the analytical model, the forces predicted by analytical model agreed closely with the finite element model's results. The fitted curve of design loadings allows an initial design stage loading estimate for cross deck structural loading, given general characteristics of length and spacing of a trimaran's hulls.http://archive.org/details/structuralloadin1094511043CIVIN

Heat stress causes oxidative stress but not inflammatory signaling in porcine skeletal muscle

Heat stress is associated with death and other maladaptions including muscle dysfunction and impaired growth across species. Despite this common observation, the molecular effects leading to these pathologic changes remain unclear. The purpose of this study was to determine the extent to which heat stress disrupted redox balance and initiated an inflammatory response in oxidative and glycolytic skeletal muscle. Female pigs (5–6/group) were subjected to thermoneutral (20 °C) or heat stress (35 °C) conditions for 1 or 3 days and the semitendinosus removed and dissected into red (STR) and white (STW) portions. After 1 day of heat stress, relative abundance of proteins modified by malondialdehyde, a measure of oxidative damage, was increased 2.5-fold (P \u3c 0.05) compared with thermoneutral in the STR but not the STW, before returning to thermoneutral conditions following 3 days of heat stress. This corresponded with increased catalase and superoxide dismutase-1 gene expression (P \u3c 0.05) and superoxide dismutase-1 protein abundance (P \u3c 0.05) in the STR but not the STW. In the STR catalase and total superoxide dismutase activity were increased by ~30% and ~130%, respectively (P \u3c 0.05), after 1 day of heat stress and returned to thermoneutral levels by day 3. One or 3 days of heat stress did not increase inflammatory signaling through the NF-κB pathway in the STR or STW. These data suggest that oxidative muscle is more susceptible to heat stress-mediated changes in redox balance than glycolytic muscle during chronic heat stress

Exploring the NRO Opportunity for a Hubble-sized Wide-field Near-IR Space Telescope -- NEW WFIRST

We discuss scientific, technical and programmatic issues related to the use of an NRO 2.4m telescope for the WFIRST initiative of the 2010 Decadal Survey. We show that this implementation of WFIRST, which we call "NEW WFIRST," would achieve the goals of the NWNH Decadal Survey for the WFIRST core programs of Dark Energy and Microlensing Planet Finding, with the crucial benefit of deeper and/or wider near-IR surveys for GO science and a potentially Hubble-like Guest Observer program. NEW WFIRST could also include a coronagraphic imager for direct detection of dust disks and planets around neighboring stars, a high-priority science and technology precursor for future ambitious programs to image Earth-like planets around neighboring stars.Comment: 76 pages, 26 figures -- associated with the Princeton "New Telescope Meeting

Heat Stress Alters Ovarian Insulin-Mediated Phosphatidylinositol-3 Kinase and Steroidogenic Signaling in Gilt Ovaries

Heat Stress (HS) compromises a variety of reproductive functions in several mammalian species. Inexplicably, HS animals are frequently hyperinsulinemic despite marked hyperthermia-induced hypophagia. Our objectives were to determine the effects of HS on insulin signaling and components essential to steroid biosynthesis in the pig ovary. Female pigs (35±4 kg) were exposed to constant thermal neutral (TN; 20°C; 35-50% humidity; n = 6) or HS conditions (35°C; 20-35% humidity; n = 6) for either 7 (n = 10) or 35 d (n = 12). After 7d, HS increased (P \u3c 0.05) ovarian mRNA abundance of the insulin receptor (INSR), insulin receptor substrate 1 (IRS1), protein kinase B subunit 1 (AKT1), low density lipoprotein receptor (LDLR), luteinizing hormone receptor (LHCGR), and aromatase (CYP19a). After 35d, HS increased INSR, IRS1, AKT1, LDLR, LHCGR, CYP19a, and steroidogenic acute regulatory protein (STAR) ovarian mRNA abundance. In addition, after 35d, HS increased ovarian phosphorylated IRS1 (pIRS1), phosphorylated AKT (pAKT), STAR and CYP19a protein abundance. Immunostaining analysis revealed similar localization of INSR and pAKT1 in the cytoplasmic membrane and oocyte cytoplasm, respectively, of all stage follicles, and in theca and granulosa cells. Collectively, these results demonstrate that HS alters ovarian insulin mediated-PI3K signaling pathway members which likely impacts follicle activation and viability. In summary, environmentally-induced HS is an endocrine disrupting exposure that modifies ovarian physiology and potentially compromises production of ovarian hormones essential for fertility and pregnancy maintenance

Effects of heat stress during porcine reproductive and respiratory syndrome virus infection on metabolic responses in growing pigs

Heat stress and immune challenges negatively impact nutrient allocation and metabolism in swine, especially due to elevated heat load. In order to assess the effects of heat stress during porcine reproductive and respiratory syndrome virus (PRRSV) infection on metabolism, 9-week old crossbred barrows were individually housed, fed ad libitum, divided into four treatments: thermo-neutral (TN), thermo-neutral PRRSV infected (TP), heat stress (HS), and heat stress PRRSV infected (HP), and subjected to two experimental phases. Phase one occurred in TN conditions (22°C) where half the animals were infected with PRRS virus (n=12), while the other half (n=11) remained uninfected. Phase two began, after 10 days with half of the uninfected (n=6) and infected groups (n=6) transported to heated rooms (35°C) for three days of continuous heat, while the rest remained in TN conditions. Blood samples were collected prior to each phase and at trial completion before sacrifice. PPRS viral load indicated only infected animals were infected. Individual rectal temperature (Tr), respiration rates (RR), and feed intakes (FI) were determined daily. Pigs exposed to either challenge had an increased Tr, (P \u3c 0.0001) whereas RR increased (P \u3c 0.0001) with heat stress, compared to TN. Average daily gain (ADG) and body weight (BW) decreased with challenges compared to TN, with the greatest loss to HP pigs. Markers of muscle degradation such as creatine kinase, creatinine, and urea nitrogen were elevated during challenges. Blood glucose levels tended to decrease in HS pigs. Heat stress tended to decrease WBC and lymphocytes and increase monocytes and eosinophils during HS. However, neutrophils were significantly increased (P \u3c 0.01) during HP. Metabolic flexibility tended to decrease in PRRS infected pigs as well as HS pigs. Fatty acid oxidation measured by CO2 production decreased in HP pigs. Taken together, these data demonstrate the additive effects of the HP challenge compared to either PRRSV or heat stress alone

Gestational Heat Stress Alters Postnatal Offspring Body Composition Indices and Metabolic Parameters in Pigs

The study objectives were to test the hypothesis that heat stress (HS) during gestational development alters postnatal growth, body composition, and biological response to HS conditions in pigs. To investigate this, 14 first parity crossbred gilts were exposed to one of four environmental treatments (TNTN, TNHS, HSTN, or HSHS) during gestation. TNTN and HSHS dams were exposed to thermal neutral (TN, cyclical 18–22°C) or HS conditions (cyclical 28–34°C) during the entire gestation, respectively. Dams assigned to HSTN and TNHS treatments were heat-stressed for the first or second half of gestation, respectively. Postnatal offspring were exposed to one of two thermal environments for an acute (24 h) or chronic (five weeks) duration in either constant TN (21°C) or HS (35°C) environment. Exposure to chronic HS during their growth phase resulted in decreased longissimus dorsi cross-sectional area (LDA) in offspring from HSHS and HSTN treated dams whereas LDA was larger in offspring from dams in TNTN and TNHS conditions. Irrespective of HS during prepubertal postnatal growth, pigs from dams that experienced HS during the first half of gestation (HSHS and HSTN) had increased (13.9%) subcutaneous fat thickness compared to pigs from dams exposed to TN conditions during the first half of gestation. This metabolic repartitioning towards increased fat deposition in pigs from dams heat-stressed during the first half of gestation was accompanied by elevated blood insulin concentrations (33%; P = 0.01). Together, these results demonstrate HS during the first half of gestation altered metabolic and body composition parameters during future development and in biological responses to a subsequent HS challenge