2,245 research outputs found

    Assessing the Treatment of Airborne Tactical High Energy Lasers in Combat Simulations

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    In March 2000, the High Energy Laser Executive Review Panel presented the Department of Defense Laser Master Plan, which reported that HEL weapons are ready for offensive and defensive applications. One candidate platform capable of performing some of the reported applications is the Advanced Tactical Laser (ATL), an Advanced Concept Technology Demonstration program which places a high energy laser weapon on a tactical aircraft, such as the V-22, C-130, or H-47. A way of assessing the utility of a new weapon system and the benefits of its inclusion in the force structure is the use of combat models. This research examines, by example, issues involved with modeling an airborne tactical high energy laser weapon in a mission level combat simulation, and evaluates possibilities to aggregate simulation results into higher level, campaign models

    EVALUATION OF THE ANTIOXIDANT ACTIVITY OF THE FLAVONOIDS ISOLATED FROM HELIOTROPIUM SINUATUM RESIN USING ORACFL, DPPH AND ESR METHODOLOGIES

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    Indexación: Web of Science; Scielo.The antioxidant capacity has been determined for a number of flavonoid compounds from Heliotropium sinuatum, a plant that grows in arid areas in the north of Chile. The methodologies used were: ORAC(FL) (oxygen radical absorbance capacity - fluorescein), DPPH (2,2-diphenyl-2-picrylhydrazyl) bleaching and electron spin resonance (ESR). These compounds were studied in homogeneous and heterogeneous media. The results showed that the 7-o-methyleriodictiol and 3-o-methylisorhamnetin are those with the highest antioxidant capacity.http://ref.scielo.org/m82cz

    Modeling of a Cantilever-Based Near-Field Scanning Microwave Microscope

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    We present a detailed modeling and characterization of our scalable microwave nanoprobe, which is a micro-fabricated cantilever-based scanning microwave probe with separated excitation and sensing electrodes. Using finite-element analysis, the tip-sample interaction is modeled as small impedance changes between the tip electrode and the ground at our working frequencies near 1GHz. The equivalent lumped elements of the cantilever can be determined by transmission line simulation of the matching network, which routes the cantilever signals to 50 Ohm feed lines. In the microwave electronics, the background common-mode signal is cancelled before the amplifier stage so that high sensitivity (below 1 atto-Farad capacitance changes) is obtained. Experimental characterization of the microwave probes was performed on ion-implanted Si wafers and patterned semiconductor samples. Pure electrical or topographical signals can be realized using different reflection modes of the probe.Comment: 7 figure

    Balanced Allocation on Graphs: A Random Walk Approach

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    In this paper we propose algorithms for allocating nn sequential balls into nn bins that are interconnected as a dd-regular nn-vertex graph GG, where d3d\ge3 can be any integer.Let ll be a given positive integer. In each round tt, 1tn1\le t\le n, ball tt picks a node of GG uniformly at random and performs a non-backtracking random walk of length ll from the chosen node.Then it allocates itself on one of the visited nodes with minimum load (ties are broken uniformly at random). Suppose that GG has a sufficiently large girth and d=ω(logn)d=\omega(\log n). Then we establish an upper bound for the maximum number of balls at any bin after allocating nn balls by the algorithm, called {\it maximum load}, in terms of ll with high probability. We also show that the upper bound is at most an O(loglogn)O(\log\log n) factor above the lower bound that is proved for the algorithm. In particular, we show that if we set l=(logn)1+ϵ2l=\lfloor(\log n)^{\frac{1+\epsilon}{2}}\rfloor, for every constant ϵ(0,1)\epsilon\in (0, 1), and GG has girth at least ω(l)\omega(l), then the maximum load attained by the algorithm is bounded by O(1/ϵ)O(1/\epsilon) with high probability.Finally, we slightly modify the algorithm to have similar results for balanced allocation on dd-regular graph with d[3,O(logn)]d\in[3, O(\log n)] and sufficiently large girth

    RNA-Seq identifies genes whose proteins are upregulated during syncytia development in murine C2C12 myoblasts and human BeWo trophoblasts

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    The fusion of villous cytotrophoblasts into the multinucleated syncytiotrophoblast is critical for the essential functions of the mammalian placenta. Using RNA-Seq gene expression, quantitative protein expression, and siRNA knockdown we identified genes and their cognate proteins which are similarly upregulated in two cellular models of mammalian syncytia development (human BeWo cytotrophoblast to syncytiotrophoblast and murine C2C12 myoblast to myotube). These include DYSF, PDE4DIP, SPIRE2, NDRG1, PLEC, GPR146, HSPB8, DHCR7, and HDAC5. These findings provide avenues for further understanding of the mechanisms underlying mammalian placental syncytiotrophoblast development

    Connecting the Lines between Hypogonadism and Atherosclerosis

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    Epidemiological studies show that atherosclerotic cardiovascular disease is a leading cause of morbidity and mortality worldwide and point to gender differences with ageing males being at highest risk. Atherosclerosis is a complex process that has several risk factors and mediators. Hypogonadism is a commonly undiagnosed disease that has been associated with many of the events, and risk factors leading to atherosclerosis. The mechanistic relations between testosterone levels, atherosclerotic events, and risk factors are poorly understood in many instances, but the links are clear. In this paper, we summarize the research journey that explains the link between hypogonadism, each of the atherosclerotic events, and risk factors. We look into the different areas from which lessons could be learned, including epidemiological studies, animal and laboratory experiments, studies on androgen deprivation therapy patients, and studies on testosterone-treated patients. We finish by providing recommendations for the clinician and needs for future research

    Ultimate Ownership and Bank Competition

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    We use a uniquely extensive branch-level dataset on deposit account interest rates, maintenance fees, and fee thresholds, and document substantial time-series and cross-sectional variation in these prices. We then examine whether variation in bank concentration helps explain the variation in prices. The standard measure of concentration, the HHI, is not correlated with any of the outcome variables. We then construct a generalized HHI (GHHI) that captures both common ownership (the degree to which banks are commonly owned by the same investors) and cross-ownership (the extent to which banks own shares in each other). The GHHI is strongly correlated with all prices. We use the growth of index funds as an arguably exogenous source of cross-sectional variation of county-level common ownership growth to suggest a causal link from the GHHI to higher prices for banking products

    A Supercooled Spin Liquid State in the Frustrated Pyrochlore Dy2Ti2O7

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    A "supercooled" liquid develops when a fluid does not crystallize upon cooling below its ordering temperature. Instead, the microscopic relaxation times diverge so rapidly that, upon further cooling, equilibration eventually becomes impossible and glass formation occurs. Classic supercooled liquids exhibit specific identifiers including microscopic relaxation times diverging on a Vogel-Tammann-Fulcher (VTF) trajectory, a Havriliak-Negami (HN) form for the dielectric function, and a general Kohlrausch-Williams-Watts (KWW) form for time-domain relaxation. Recently, the pyrochlore Dy2Ti2O7 has become of interest because its frustrated magnetic interactions may, in theory, lead to highly exotic magnetic fluids. However, its true magnetic state at low temperatures has proven very difficult to identify unambiguously. Here we introduce high-precision, boundary-free magnetization transport techniques based upon toroidal geometries and gain a fundamentally new understanding of the time- and frequency-dependent magnetization dynamics of Dy2Ti2O7. We demonstrate a virtually universal HN form for the magnetic susceptibility, a general KWW form for the real-time magnetic relaxation, and a divergence of the microscopic magnetic relaxation rates with precisely the VTF trajectory. Low temperature Dy2Ti2O7 therefore exhibits the characteristics of a supercooled magnetic liquid; the consequent implication is that this translationally invariant lattice of strongly correlated spins is evolving towards an unprecedented magnetic glass state, perhaps due to many-body localization of spin.Comment: Version 2 updates: added legend for data in Figures 4A and 4B; corrected equation reference in caption for Figure 4

    MAKING HEADS OR TAILS: AN ICONOGRAPHIC ANALYSIS OF LATE MISSISSIPPIAN RIM-EFFIGY BOWLS IN THE CENTRAL MISSISSIPPI RIVER VALLEY

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    Symbolically charged ceramic rim-effigy bowls, characterized by figural head and tail adornments, are hallmarks of the Late Mississippian period in the central Mississippi River valley (CMV). Hundreds of whole rim-effigy bowls, most often depicting serpents, birds, or humans, have been collected at sites from southeastern Missouri to northwestern Mississippi. However, a comprehensive iconographic analysis of the CMV rim-effigy bowl corpus – specifically focused on visual style and theme – has never been conducted. A systematic review of the corpus’s imagery suggests that CMV rim-effigy bowls acted as materializations of the Mississippian cosmos, reinforcing the principle of cosmic balance. Further, given discrete concentrations of bowl styles and themes across the region, localized religious collectives – perhaps sodalities – may have produced their own rim-effigy bowls for use during charter rites or ceremonies. More broadly, by reviewing an understudied ceramic corpus, this study furthers understandings of Mississippian art and iconography in the CMV and beyond.Master of Art
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