1,739 research outputs found

    Neuroenhancement of exposure therapy in anxiety disorders

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    Although exposure-based treatments and anxiolytic medications are more effective than placebo for treating anxiety disorders, there is still considerable room for further improvement. Interestingly, combining these two modalities is usually not more effective than the monotherapies. Recent translational research has identified a number of novel approaches for treating anxiety disorders using agents that serve as neuroenhancers (also known as cognitive enhancers). Several of these agents have been studied to determine their efficacy at improving treatment outcome for patients with anxiety and other psychiatric disorders. In this review, we examine d-cycloserine, yohimbine, cortisol, catecholamines, oxytocin, modafinil, and nutrients such as caffeine and amino fatty acids as potential neuroenhancers. Of these agents, d-cycloserine shows the most promise as an effective neuroenhancer for extinction learning and exposure therapy. Yet, the optimal dosing and dose timing for drug administration remains uncertain. There is partial support for cortisol, catecholamines, yohimbine and oxytocin for improving extinction learning and exposure therapy. There is less evidence to indicate that modafinil and nutrients such as caffeine and amino fatty acids are effective neuroenhancers. More research is needed to determine their long term efficacy and clinical utility of these agents.R34 MH086668 - NIMH NIH HHS; R01 AT007257 - NCCIH NIH HHS; R21 MH101567 - NIMH NIH HHS; R34 MH099311 - NIMH NIH HHS; R21 MH102646 - NIMH NIH HHS; K23 MH100259 - NIMH NIH HHS; R01 MH099021 - NIMH NIH HH

    Optical excitations in organic molecules, clusters and defects studied by first-principles Green's function methods

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    Spectroscopic and optical properties of nanosystems and point defects are discussed within the framework of Green's function methods. We use an approach based on evaluating the self-energy in the so-called GW approximation and solving the Bethe-Salpeter equation in the space of single-particle transitions. Plasmon-pole models or numerical energy integration, which have been used in most of the previous GW calculations, are not used. Fourier transforms of the dielectric function are also avoided. This approach is applied to benzene, naphthalene, passivated silicon clusters (containing more than one hundred atoms), and the F center in LiCl. In the latter, excitonic effects and the 1s2p1s \to 2p defect line are identified in the energy-resolved dielectric function. We also compare optical spectra obtained by solving the Bethe-Salpeter equation and by using time-dependent density functional theory in the local, adiabatic approximation. From this comparison, we conclude that both methods give similar predictions for optical excitations in benzene and naphthalene, but they differ in the spectra of small silicon clusters. As cluster size increases, both methods predict very low cross section for photoabsorption in the optical and near ultra-violet ranges. For the larger clusters, the computed cross section shows a slow increase as function of photon frequency. Ionization potentials and electron affinities of molecules and clusters are also calculated.Comment: 9 figures, 5 tables, to appear in Phys. Rev. B, 200

    Ultrasonic cavitation near a tissue layer

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    AbstractIn this paper we examine the dynamics of an initially stable bubble due to ultrasonic forcing by an acoustic wave. A tissue layer is modelled as a density interface acted upon by surface tension to mimic membrane effects. The effect of a rigid backing to the thin tissue layer is investigated. We are interested in ultrasound contrast agent type bubbles which have immediate biomedical applications such as the delivery of drugs and the instigation of sonoporation. We use the axisymmetric boundary integral technique detailed in Curtiss et al. (J. Comput. Phys., 2013, submitted) to model the interaction between a single bubble and the tissue layer. We have identified a new peeling mechanism whereby the re-expansion of a toroidal bubble can peel away tissue from a rigid backing. We explore the problem over a large range of parameters including tissue layer depth, interfacial tension and ultrasonic forcing.</jats:p

    Van der Waals forces in density functional theory: perturbational long-range electron interaction corrections

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    Long-range exchange and correlation effects, responsible for the failure of currently used approximate density functionals in describing van der Waals forces, are taken into account explicitly after a separation of the electron-electron interaction in the Hamiltonian into short- and long-range components. We propose a "range-separated hybrid" functional based on a local density approximation for the short-range exchange-correlation energy, combined with a long-range exact exchange energy. Long-range correlation effects are added by a second-order perturbational treatment. The resulting scheme is general and is particularly well-adapted to describe van der Waals complexes, like rare gas dimers.Comment: 8 pages, 1 figure, submitted to Phys. Rev.

    Sugar beet growing

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    The interest that attaches to beet growing in Iowa induced this station to conduct an experiment embracing conditions common to this industry by the farmer. Seed of German (Klein Wanzlebener) and French (Dippes Vilmorin) varieties were obtained from the Department of Agriculture; also a French variety called Desprez from Oxnard Bros., Grand Island, Nebraska. The ground selected was a piece of fall plowing adjoining timber. Some of it had been recently cleared. The piece comprised the following varieties of soil: Upland, sandy loam, low rich loam, medium sandy loam, timber clay loam, and stiff timber clay, all comparatively new. In order to ascertain the best time to plant sugar beets we begun April 15 and planted once each week, until May 25. We also desired to ascertain what benefit, if any, would be derived from fertilizing. Lime was used. A commercial fertilizer containing ammonia, phosphoric acid, and potash, valued especially for sugar cane in the South, was used; also ammoniated super-phosphate

    Effect of feed upon the quality of milk

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    The teachings of some of our prominent agricultural chemists upon this subject— teachings which have received wide circulation only so recently that they will be new to most of our readers— may be stated as follows: First, In general— that while quantity of milk is largely dependent upon the kind of feed consumed, quality (i. e. composition) is almost independent of it; in other words that the quality of milk cannot be materially changed by varying the kind or composition of the feed. Second, In detail— that neither the percentage of fat nor o f total solids in the milk is materially influenced by the kind or the composition of feed consumed; that these percentages are fixed by the constitution or individuality of each animal, and so firmly fixed that to change them to any considerable extent and for any length of time, by feeding, is impossible

    Hog experiment No. 1

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    The result of this experiment shows that 2000 pounds of grain produced 6263/4 pounds live weight, or 17.3 pounds of growth for every bushel of corn and equivalent; that we can approximate one dollar per bushel for corn when pork is five and one-half cents per pound; that the dam can be made to increase in flesh during the suckling period; that the proper balancing of the ration is necessary to secure these results. The object of this experiment is to determine the most profitable development of a litter of pigs and the maintenance of the dam. In other words to produce the greatest possible live weight with a given quantity of grain without detriment to the vigor and constitution of the growing animal. The experiment, therefore, involves two points, namely, increase of flesh and fat in proper balance with increase of bone and skin. The subject is a registered Poland China sow, two years old. She was purchased of W. M. McFadden, West Liberty, Iowa. She scored second in points of excellence at the State Fair one year ago. So we have a good animal to start with. She farrowed March 3, 1891. Her litter consisted of four pigs, three boars and one sow. The pigs and dam were weighed when the pigs were thirty-six hours old. The weight of the pigs, was thirteen and one-fourth pounds; weight of dam, 348 pounds. The weighing was done March 4, at two o’ clock p. m . The supplementary feed was prepared by mixing ground barley, oil meal, corn and cob meal and bran, the mixture being soaked thirty-six hours in cold water before feeding. The principal feed was ear corn, and shelled corn soaked. The sow was fed three times a day during the first two periods and twice a day thereafter

    Calf feeding experiments

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    The state of Iowa has within a few years developed dairying in many counties to such an extent that great interest attaches to methods of feeding calves during the first four months of their lives, and until they have reached the age when grains, grasses and fodders will carry them on through the rearing period. Our farmers adopt various methods in calf raising. Special beef producers permit the calf to follow the dam until it is five or six months old, others yard the calves, and admit the cows twice a day. Those who want milk as a feature of profit resort to various methods. Some farmers require one cow to suckle two calves, while they milk the other cow. Others milk the cows, and after the calf has reached a certain age, varying with varying opinions of the proper time to stop feeding new milk, they raise the calf on skim milk, with different grains added. Still others, feed skim milk from the beginning, caring little for the calf, and relying for profit on the milk. What is most economical has not been demonstrated. The state has such great abundance of corn and other grains, such fine grasses and fodders that, the production of beef will always be a leading industry. It is also well settled that, the average farmer can not afford to give all of a cow’s milk for a year, to the raising of her calf, and cows that suckle seldom give milk long after the calf is removed. Our farmers who desire to make milk a profitable feature of the farm are leaning more and more to the belief that the calf must be raised by hand

    A feeding experiment for milk

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    This Feeding experiment indicates that corn meal fed with corn fodder, or corn ensilage, results in the more rapid decrease of milk, and its fat, and solids, than the advance in the period of lactation justifies. That corn meal fed with sorghum ensilage results in very rapid decrease in milk, and milk fat and solids, and that the combination is not profitable. That corn meal fed with roots and clover hay is palatable and gives good results, without considering the cost of feeds, that was not normal during the experiment

    Experiment in feeding for milk

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    For the purpose of learning the comparative value of Iowa feeding stuffs for milk, an experiment has been conducted with eight cows during a space of sixty days. Upon taking possession of the Station and Farm the present management found corn fodder, corn ensilage, cane ensilage and roots, at their disposal, and resolved to begin a system of investigation that is intended to embrace everything grown on Iowa soils that can be profitably turned into milk and meats. We desired to study the farm animals with a view to learning their value, make tests of the yield of all the cows as regards quality and quantity of milk, so as to select, and reject, with intelligence, and put the herds upon the highest plane of usefulness. The Station and Farm had about thirty cows giving milk, and from these we selected eight whose milking seasons would not terminate during the time they would be under trial. Of the six distinct breeds on the grounds, we selected two thoroughbred Holsteins, Nos. 114 and 115, a grade Holstein No. 64, a thoroughbred Short horn No. 219, a grade Ayrshire and short horn No. 40, a grade Jersey No. 38, and two grade Short horns Nos. 3 and 37. The numbers are the names of the cows, all grades being numbered between one and one hundred, Holsteins between one hundred and two hundred, Short horns between two hundred and three hun-hundred, and, as we will use some of these cows in other experiments for future reports, we retain the numbers by which all the farm workmen know them
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