Potential for Electropositive Metal to Reduce the Interactions of Atlantic Sturgeon with Fishing Gear

Atlantic sturgeon (Acipenser oxyrhynchus) populations have been declared either endangered or threatened under the U.S. Endangered Species Act. Effective measures to repel sturgeon from fishing gear would be beneficial to both fish and fishers because they could reduce both fishery‐associated mortality and the need for seasonal and area closures of specific fisheries. Some chondrostean fishes (e.g., sturgeons and paddlefishes) can detect weak electric field gradients (possibly as low as 5 Μv/cm) due to arrays of electroreceptors (ampullae of Lorenzini) on their snout and gill covers. Weak electric fields, such as those produced by electropositive metals (typically mixtures of the lanthanide elements), could therefore potentially be used as a deterrent. To test this idea, we recorded the behavioral responses of juvenile Atlantic sturgeon (31–43 cm fork length) to electropositive metal (primarily a mixture of the lanthanide elements neodymium and praseodymium) both in the presence and absence of food stimuli. Trials were conducted in an approximately 2.5 m diameter × 0.3 m deep tank, and fish behaviors were recorded with an overhead digital video camera. Video records were subsequently digitized (x, y coordinate system), the distance between the fish and the electropositive metal calculated, and data summarized by compiling frequency distributions with 5‐cm bins. Juvenile sturgeon showed clear avoidance of electropositive metal but only when food was present. On the basis of our results, we conclude that the electropositive metals, or other sources of weak electric fields, may eventually be used to reduce the interactions of Atlantic sturgeon with fishing gear, but further investigation is needed. El Potencial del Metal Electropositivo para Reducir las Interacciones del Esturión Atlántico con Instrumentos de Pesca Bouyoucos, Bushnell & Brill 13–003 Resumen Las poblaciones del esturión atlántico ( Acipenser oxyrhynchus ) han sido declaradas como en peligro o amenazadas bajo el Acta de Especies en Peligro de los Estados Unidos. Las medidas efectivas para repeler a los esturiones de los instrumentos de pesca serían benéficas para los peces y los pescadores ya que podrían reducir la mortalidad asociada a la pesca y la necesidad de los cierres temporales y de área de pesquerías específicas. Algunos peces chondrosteos (p. ej.: esturiones y peces espátula) pueden detectar gradientes débiles de campos eléctricos (posiblemente tan bajos como 5 μV cm −1 ) debido a grupos de electroreceptores (ámpulas de Lorenzini) en su hocico y opérculos. Los campos eléctricos débiles, como aquellos producidos por metales electropositivos (comúnmente mezcla de elementos lantánidos), podrían entonces ser usados potencialmente como un disuasivo. Para probar esta idea, filmamos las respuestas conductuales de esturiones juveniles (31 – 43 cm de largo) a metales electropositivos (principalmente una mezcla de los elementos lantánidos neodimio y praseodimio) tanto en la presencia como en la ausencia de estímulos de alimento. Las pruebas se realizaron en un tanque de ≈ 2.5 metros de diámetro x 0.3 m de profundidad, y las conductas de los peces se filmaron con una cámara digital de video colocada sobre el tanque. Las filmaciones después se digitaron (sistema de coordenadas x, y), se calculó la distancia entre los peces y el metal electropositivo y se resumió la información al compilar las distribuciones de la frecuencia con contenedores de 5 cm. Los esturiones juveniles mostraron clara evitación del metal electropositivo pero sólo cuando el alimento estaba presente. Basándonos en nuestros resultados, concluimos que los metales electropositivos, u otras fuentes de campos eléctricos débiles, puede ser usada eventualmente para reducir las interacciones del esturión atlántico con los instrumentos de pesca, pero es necesario llevar a cabo más investigaciones.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/102646/1/cobi12200.pd

Liver X receptor-dependent inhibition of microglial nitric oxide synthase 2

Background The nuclear receptor liver X receptor (LXR) exerts transcriptional control over lipid metabolism and inflammatory response in cells of the myeloid lineage, suggesting that LXR may be a potential target in a number of chronic neuroinflammatory and neurodegenerative diseases where persistent microglial activation has been implicated in the pathogenesis. Methods The effect of LXR activation on microglia and central nervous system (CNS) inflammation was studied using a synthetic LXR agonist in cultured microglia, a microglial cell line and experimental allergic encephalomyelitis (EAE), an animal model of CNS inflammation. Results LXR activation inhibited nitric oxide synthase 2, inducible (Nos2) expression and nitric oxide production in lipopolysaccharide (LPS)-stimulated microglia. Inhibition of microglial activation in response to interferon-γ was less reliable. In LPS-stimulated cells, LXR activation did not inhibit nuclear translocation of NF-kappaB1 p50. Instead, LXR-dependent Nos2 repression was associated with inhibition of histone 4 acetylation and inhibition of NF-kappaB1 p50 binding at the Nos2 promoter. Histone acetylation and NF-kappaB1 p50 binding were mechanistically linked, and histone deacetylase (HDAC) activity appeared to be important for LXR-dependent transcriptional repression of Nos2. Analysis of CNS gene expression in animals undergoing EAE showed that the expressions of Lxr and LXR-dependent genes were downregulated during CNS inflammation. Nevertheless, administration of LXR agonist GW3965 during the effector phase of EAE delayed the onset of clinical disease and reversed the diminished expression of LXR-dependent reverse cholesterol transport genes. However, the CNS expressions of Nos2 and other inflammatory genes were not significantly inhibited by LXR activation in EAE, and clinical disease severity was comparable to vehicle controls at later time points in LXR agonist treated animals. Conclusions LXR can be targeted to modulate microglial activation. LXR-dependent repression of inflammatory genes may be stimulus-dependent and impaired by HDAC inhibition. Endogenous LXR activity does not appear to modulate CNS inflammation, but LXR activity can be partially restored in the CNS by administration of exogenous LXR agonist with an impact on clinical disease severity at early, but not late, time points in EAE

Validation of the Equations Used in Determining Dry Matter Intake, and Metabolizable Protein Requirements for Finishing Lambs as used in the Sheep Companion Module to BRaNDS

The growth equations published in the 2006 NRC “Nutrient Requirements of Small Ruminants” along with the additions added to these equations when used in the Sheep Companion Module to BRaNDS appear to provide reasonable estimations of performance of feeder lambs

Efficacy of Grazing Stockpiled Perennial Forages for Winter Maintenance of Beef Cows

In a three year study, wintering systems utilizing the grazing of stockpiled perennial hay crop forages or corn crop residues were compared to maintaining cows in a drylot. In the summer of 1992, two cuttings of hay were harvested (June 22 and August 2) from three 10-acre fields containing “Johnstone” endophyte-free tall fescue and “Spreador II” alfalfa, and one cutting of hay was harvested from three 10- acre fields of smooth brome grass. “Arlington” red clover was frost-seeded into the smooth bromegrass fields in 1993 and into tall fescue-alfalfa and smooth bromegrass fields into 1994. Two cuttings of hay were harvested from all fields in subsequent years, and three-year average hay yields for tall fescue-alfalfa and smooth bromegrass-red clover were 4,336 and 3,481 pounds per acre, respectively. Regrowth of the forage following the August hay harvest of each year was accumulated for winter grazing. Following a killing frost in each year, two fields of each stockpiled forage were stocked with cows in midgestation at two acres per cow. Two 10-acre fields of corn crop residues were also stocked at two acres per cow, following the grain harvest. Mean dry matter forage yields at the initiation of grazing were 1,853, 2,173 and 5,797 pounds per acre for fields containing tall fescue-alfalfa, smooth bromegrass-red clover, and cornstalks, respectively. A drylot was stocked with 18 cows in 1992 and 1993 and 10 cows in 1994. All cows were fed hay as necessary to maintain a body condition score of five. During grazing, mean losses of organic matter were -6.4, -7.6, and -10.7 pounds per acre per cow from tall fescue-alfalfa, smooth bromegrass-red clover, and cornstalk fields. Average organic matter loss rates from stockpiled forages due to weathering alone were equal to only 30% of the weathering losses of the corn crop residues. In vitro digestibility of both stockpiled forages and cornstalks decreased at equal rates during grazing each year, with respective annual loss rates of .14, .08, and .06% per day. Cows grazing corn crop residues required an average of 1,321 pounds per cow less hay than cows maintained in the drylot to maintain equivalent body condition during the grazing season. Cows grazing tall fescue-alfalfa or smooth bromegrass-red clover had body weight gains and condition score changes equal to cows maintained in a drylot but required 64% and 62% less harvested hay than cows in the drylot during the grazing season. Over the entire stored forage cows grazing tall fescue-alfalfa and smooth bromegrass-red clover required an average of 2,390 and 2,337 pounds per cow less than those maintained in the drylot. Because less hay was needed to maintain cows grazing stockpiled forages, average annual excesses of 5,629 and 3,868 pounds of hay dry matter per cow remained in the stockpiled tall fescue-alfalfa and smooth bromegrass-red clover systems

Evaluation of a Year-Round Grazing System: Winter Progress Report

The winter component of a year-round grazing system involving grazing of corn crop residues followed by grazing stockpiled grass legume forages was compared at the McNay Research Farm with that of the winter component of a minimal land system that maintained cows in drylot,. In the summer of 1995, two cuttings of hay were harvested from two 15-acre fields containing “Johnston” endophyte-free tall fescue and red clover, and two cuttings of hay were taken from two 15-acre fields of smooth bromegrass and red clover. Hay yields were 4,236 and 4,600 pounds of dry matter per acre for the tall fescue--red clover and smooth bromegrass--red clover. Following grain harvest four 7.5-acre fields containing corn crop residue were stocked with cows at midgestation at an allowance of 1.5 acres per cow. Forage yields at the initiation of corn crop grazing were 3,766pounds of dry matter per acre for corn crop residue, 1,748 pounds for tall fescue--red clover, and 1,.880 pounds for smooth bromegrass--red clover. Corn crop residues and stockpiled forages were grazed in a strip stocking system. For comparison, 20 cows were placed in two drylots simultaneously to the initiation of corn crop grazing where they remained throughout the winter and spring grazing seasons. Cows maintained in drylot or grazing corn crop residue and stockpiled forages were supplemented with hay as large round bales to maintain a body condition score of five. No seasonal differences in body weight and body condition were observed between grazing cows or cows maintained in drylot, but grazing cows required 87% and 84% less harvested hay than cows in drylot during the winter and spring respectively. Because less hay was needed to maintain grazing cows, an excess of 11,905 and 12,803 pounds of hay dry matter per cow remained in the year-round grazing system. During corn crop grazing, organic matter yield decreased at 27.3 pounds of organic matter per day from grazed areas of corn crop residue. Organic matter losses due to weathering were 9.4, 12.9, and 15.8 pounds per day in corn crop residue, tall fescue-red clover and smooth bromegrass-red clover. Organic matter losses from grazed and ungrazed areas during stockpiled grazing were 7.3 and 6.9 for tall fescue--red clover and 2.1, 2.9 for smooth bromegrass--red clover

Evaluation of a Year-Round Grazing System: Summer Cow-Calf Progress Report

A comparison was made between two different summer grazing systems. One system was the summer component of a year-round grazing system, involving the rotational stocking of smooth bromegrass--orchardgrass--birdsfoot trefoil pastures and winter stockpiles pastures with cowcalf pairs co-grazing with stocker yearlings at .75 animal units per acre. That system was compared with a minimal land system involving the rotational stocking of smooth bromegrass--orchardgrass-- birdsfoot trefoil summer pastures with cow-calf pairs grazing at .64 animal units per acre and hay removal from 25% of the pasture. Stocker yearlings or hay removal were used as management tools to remove excess forage and optimize forage quality. Hay was removed once from three fourths of the winter stockpiled pastures and one fourth of the allocated summer pastures. Cow-calf pairs grazing in the year-round system utilized on fourth of the winter stockpile pastures due to lack of forage, whereas cow-calf pairs grazing with hay removal were supplemented with harvested hay for two weeks during the summer. Grazing system did not affect cow body weight, condition score, or daily calf weight gain. Growing animal production per acre was affected by grazing system, with the minimal land system having a higher production level

Evaluation of Year-round Forage Management Systems for Spring- and Fall-Calving Beef Cows

Stored feeds make up almost half the cost of production for cow–calf enterprises in Iowa. Therefore, any reduction in the amount of stored feeds needed to maintain cows through the winter can have an impact on overall costs of maintaining the herd. Two resources that may be used to reduce the use of stored feeds are corn-crop residues and stockpiled perennial forages, which may be grazed during the winter. The objective of this experiment was to design and evaluate grazing systems to utilize such resources

The effect of acquisition and analysis automation failure in a low-fidelity multitasking system

Research into the effect of automation on human multitasking performance is primarily focused on Decision Automation (a machine suggesting a certain course of action for a human operator to take) and Action Automation (a machine carrying out a certain course of action on behalf of the human operator) while Acquisition Automation (a machine provides assistance which helps a human operator in sensing information) and Analysis Automation (a machine provides information predicting the future state of a system) have been acknowledged as types of automation but largely ignored. The inclusion of the former in systems which require human multitasking is beneficial, while the effects of the latter are unclear. In order to determine said effects a study was conducted using a low fidelity simulation of a multitasking system with No Automation, Acquisition Automation, and Analysis Automation states, as well as failure states for those systems with automation included. Results show no statistically significant difference in performance between systems with the automation enabled versus those with the automation in a failed state, nor was there any statistically significant difference between the performance of groups with no automation present and those with automation present (in both active and failed states)