cssi/SciSciGPT-SciSciNet huggingface dataset:
Is the window of opportunity closing for Brazilian youth? Labor market trends and business cycle effects

Brazilian youth today face enormous difficulties in penetrating the labor market, a situation much different from the one 25 years ago. While females have entered the labor market and increased their employment rate many are unemployed. Youth unemployment reached 19.1 percent in 2002; up from 4.5 percent in 1978. This paper analyzes long-run trends, as well as the impact of business cycles, on Brazilian youth in the labor market. To do this, the paper uses Brazilian household data (PNAD) spanning 1978-2002 and covering 290,000-530,000 individuals per year. Two main findings are presented: first, the labor market situation for youth has deteriorated and did especially so in the 1990s. In particular, labor force participation and employment have been decreasing relatively more for youth than for adults, but also wages decreased and unemployment increased for youth. Second, Brazilian youth were adversely impacted by business cycle fluctuations. During recessions youth lost ground compared to adults in the labor market in terms of labor force participation, employment, and to some extent unemployment. During expansions youth did not catch up on adults; in fact, the gap continued to widen.
A methodology for custom VLSI layout

In this paper, we present a new methodology for custom VLSI layout which aims at a low turnaround time and a high quality of design. VLSI circuits are highly complex, and to speed up the design process we exploit the hierarchical structure of a design, splitting the problem domain into several levels. The process of layout at each level is divided into steps such as placement of rectangular blocks, determining block dimensions, determining interconnection paths, etc. In order to obtain high quality designs, we have systematically analyzed the relationship among the parameters being computed at various steps and have accordingly organized the flow of data and control through these steps. There are two novel features in our scheme. First, we do not follow the usual pure top-down or pure bottom-up approach, so as to take into account the influence of design decisions at the higher levels on design decisions made at the lower levels, as well as vice versa. For example, we determine the geometry of a block taking into consideration the context in which it is placed, as well as the geometries of the lower level blocks it encloses. Second, we perform a look-ahead operation when the values of some parameters are needed before they are actually deterministically computable by the process. For example, at the time of placement, the area required for routing is estimated statistically (before doing the actual routing) so that a more routable placement can be obtained, thereby avoiding some unnecessary iterations.
‘I don't have anything to hide, but … ': the challenges and negotiations of social and mobile media privacy for non-dominant youth

Drawing from interviews and focus groups with teens in a low-income and ethnically diverse high school in central Texas, this paper explores the unique social privacy challenges and strategies of low-income and non-dominant youth. Situating the research in a broader context in which non-dominant teens are increasingly surveilled, I demonstrate how teens manage social privacy in at least three ways. First, they negotiate liminal boundaries of what constitutes a communal or shareable mobile device, which are structured around financial constraints. Second, through nonuse, they actively resist the ways mobile and social media reconfigure social and physical spaces. Third, they deliberately use multiple platforms as a way to cope with evolving privacy settings, social norms, and technological affordances; this is a deliberate strategy intended to resist social convergence. Because low-income and non-dominant youth are increasingly surveilled by adults, peers, and institutions, it is imperative that they find ...
Exchange energy and generalized polarization in the presence of spin-orbit coupling in two dimensions

We discuss a general form of the exchange energy for a homogeneous system of interacting electrons in two spatial dimensions, which is particularly suited in the presence of a generic spin-orbit interaction. The theory is best formulated in terms of a generalized fractional electronic polarization. Remarkably, we find that a net generalized polarization does not necessarily translate into an increase in the magnitude of the exchange energy, a fact that, in turn, favors unpolarized states. Our results account qualitatively for the findings of recent experimental investigations.
Levodopa-Induced dopamine receptor hypersensitivity

Chronic administration of levodopa with a dopa decarboxylase inhibitor to young guinea pigs resulted in increased behavioral response to levodopa itself as well as to d-amphetamine and apomorphine. The chronic levodopa pretreatment resulted in a decreased threshold for stereotyped behavior for all three types of dopamine agonists. Our results suggest that chronic agonism with levodopa can produce postsynaptic dopaminergic hypersensitivity within the striatum. These experiments act as a model of levodopa-induced dyskinesia in patients receiving long-term levodopa therapy. The results reported here suggest that receptor site hypersensitivity may play a role in levodopa-induced dyskinesias and that chronic levodopa (dopamine) agonism may itself be involved in the pathogenesis of this movement disorder.
Radiation effects in magnetic and superconducting materials

Many of the newly developed materials, such as rare-earth permanent magnets, amorphous alloys and oxide superconductors, have important applications in radiation environments. These environments can have various negative or beneficial effects on the properties, depending on the amount of radiation and the nature of material. Properties such as the critical current in superconductors can actually be increased by radiation, while critical temperature is decreased. More detailed study of the mechanisms responsible for such radiation-induced changes may lead to materials with greater stability in these challenging environments.
Measurement of the Lense-Thirring drag on high-altitude, laser-ranged artificial satellites

We describe a new method of measuring the Lense-Thirring relativistic nodal drag using LAGEOS together with another high-altitude, laser-ranged, similar satellite with appropriately chosen orbital parameters. We propose, for this purpose, that a future satellite such as LAGEOS II have an inclination supplementary to that of LAGEOS. The experiment proposed here would provide a method for experimental verification of the general relativistic formulation of Mach's principle and measurement of the gravitomagnetic field.
An Electro-Optic Direction Sensor

A single-axis star sensor is described in which a wave plate having direction-dependent retardation, together with an electro-optic modulator, provides the basis for indicating the direction of a distant point source of light. An alternating current photosignal is obtained, thus avoiding problems associated with detector drift. An analysis of the nominal sensor performance is compared with measurement and found to be in good agreement. The effect of varying the optical geometry on field of view is calculated. The effective noise input is evaluated. Satisfactory tracking of a + 1 magnitude star with a 1 cm aperture and a photomultiplier detector was demonstrated, showing a signal-to-noise ratio of about 50 on an rms basis.
Combinatorial invariants of multidimensional topological network data

Modern applications of algebraic topology to point-cloud data analysis have motivated active investigation of combinatorial clique complexes — multidimensional extensions of combinatorial graphs. We show that meaningful invariants of such spaces are reflected in the combinatorial properties of an associated family of linear matroids and discuss matroid-theoretic approaches to several problems in computational topology. Our results allow us to derive estimates of the summary statistics of related constructs for random point cloud data, which we discuss for several sampling distributions in R2 and R3.
Hollow waveguides for sensor applications

Hollow waveguides offer applications in remote thermometry and spectroscopy because they transmit infrared radiation and possess chemical and mechanical durability, coupled with high melting points. As in solid dielectric optical fiber, the radiation is propagated by total internal reflection when the refractive index of the cladding is less than that of the air core (n© (1991) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Quaternary glaciations and environments of northern Isla Chiloé, Chile

Author9s Note. I should like to preface this paper with a few remarks, as the work of Richard Foster Flint, who died in June 1976, was a major key to interpreting the Quaternary of Isla Chiloe. Fortunately, he was well along on preparing a map of the glacial deposits, and the geological substance of this paper is drawn from this map and the careful and systematic notes he took in the field. Our field time was during January and February 1976. For Richard Foster Flint, the study was looked upon as an opportunity to relate the glacial events that he and Francisco Fidalgo described at the same latitude on the east side of the Andes in Argentina. For me, the study was a rare sequel to previous studies of Quaternary stratigraphic palynology in southern Chile. The lowland of northern Isla Chiloe was glaciated by piedmont glaciers of Andean origin. Three offlapping layers of drift are, respectively, thoroughly weathered (Fuerte San Antonio), partly weathered (Intermediate), and fresh (Llanquihue). The coldest climatic regime, shown by the stratigraphic palynology, prevailed when the Fuerte San Antonio drift was deposited. The Intermediate drift dates from at least 57,000 yr B.P. and the Llanquihue from at least 43,000 yr B.P.
Formation of nets of corner-shared bicapped gold squares in SrAu3Ge: how a BaAl4-type derivative reconciles fewer valence electrons and the origin of its uniaxial negative thermal expansion.

SrAu3Ge was synthesized by direct fusion of the mixed elements at high temperature followed by annealing treatments, and its structure was determined by single crystal X-ray diffraction means in space group (Pearson symbol: tP10) P4/nmm, a = 6.264(1) A, c = 5.5082(9) A, Z = 2 at room temperature. The structure of SrAu3Ge, a reapportioned √2 × √2 × 1 superstructure of CeMg2Si2 (P4/mmm), exhibits checkerboard nets of corner-shared bicapped Au squares (or corner-shared Au(Au4/2)Ge octahedra), in which the apical Au–Ge pairs in adjoining nets are strongly interbonded in the c direction. This motif contrasts with that of the common BaAl4 (I4/mmm) prototype in which Al squares in comparable layers are alternately monocapped by Al from the top or the bottom. Typical examples show valence electron counts (vec) between 12 and 16 for the BaAl4 type and that for CeMg2Si2 is similar, 15. The special stability of SrAu3Ge, with vec = 9, derives from significant relativistic contribution of the Au 5d10 states to the Au–...
Ability-Tracking, Instructional Time, and Better Pedagogy: The Effect of Double-Dose Algebra on Student Achievement †

This paper provides new evidence on tracking by studying an innovative curriculum implemented by Chicago Public Schools (CPS). In 2003, CPS enacted a double-dose algebra policy requiring 9th grade students with 8th grade math scores below the national median to take two periods of algebra instead of one. This policy led schools to sort students into algebra classes by math ability, so that tracking increased in all algebra classes. We show that double-dosed students are exposed to a much lower-skilled group of peers in their algebra classes but nonetheless benefit substantially from the additional instructional time and improved pedagogy.
The Evolving Role of HIV Counseling and Testing in Resource-limited Settings: HIV Prevention and Linkage to Expanding HIV Care Access.

The role of voluntary counseling and testing (VCT)of HIV in resource-limited settings has recently broadened from primarily that of a prevention intervention to its identification as the key entry point into expanding access to life-saving antiretroviral therapy, additional HIV-specific medical care, and other support services. To fulfill this expanded mandate, calls for routine counseling and testing in diverse health care settings, in addition to other innovative approaches to traditional VCT, are emerging. The efficacy and cost-effectiveness of traditional facility-based VCT with respect to risk-behavior reduction of HIV have been demonstrated rigorously in resource-limited settings. Additional research is needed urgently to evaluate the feasibility, acceptability, and effectiveness of streamlined counseling and testing interventions that seek to reach as many individuals as possible to meet dual prevention and treatment goals.
Geometric invariants of spaces with isolated flats

Abstract We study those groups that act properly discontinuously, cocompactly, and isometrically on CAT ( 0 ) spaces with isolated flats. The groups in question include word hyperbolic CAT ( 0 ) groups as well as geometrically finite Kleinian groups and numerous two-dimensional CAT ( 0 ) groups. For such a group we show that there is an intrinsic notion of a quasiconvex subgroup which is equivalent to the subgroup being undistorted. We also show that the visual boundary of the CAT ( 0 ) space is actually an invariant of the group. More generally, we show that each quasiconvex subgroup of such a group has a canonical limit set which is independent of the choice of overgroup. The main results in this article were established by Gromov and Short in the word hyperbolic setting and do not extend to arbitrary CAT ( 0 ) groups.
A General Circulation Model for Gaseous Exoplanets with Double-gray Radiative Transfer

We present a new version of our code for modeling the atmospheric circulation on gaseous exoplanets, now employing a 'double-gray' radiative transfer scheme, which self-consistently solves for fluxes and heating throughout the atmosphere, including the emerging (observable) infrared flux. We separate the radiation into infrared and optical components, each with its own absorption coefficient, and solve standard two-stream radiative transfer equations. We use a constant optical absorption coefficient, while the infrared coefficient can scale as a power law with pressure; however, for simplicity, the results shown in this paper use a constant infrared coefficient. Here we describe our new code in detail and demonstrate its utility by presenting a generic hot Jupiter model. We discuss issues related to modeling the deepest pressures of the atmosphere and describe our use of the diffusion approximation for radiative fluxes at high optical depths. In addition, we present new models using a simple form for magnetic drag on the atmosphere. We calculate emitted thermal phase curves and find that our drag-free model has the brightest region of the atmosphere offset by {approx}12 Degree-Sign from the substellar point and a minimum flux that is 17% of the maximum, while the model with the strongest magneticmore » drag has an offset of only {approx}2 Degree-Sign and a ratio of 13%. Finally, we calculate rates of numerical loss of kinetic energy at {approx}15% for every model except for our strong-drag model, where there is no measurable loss; we speculate that this is due to the much decreased wind speeds in that model.« less
The Currency Union Effect on Trade: Early Evidence from EMU

In this paper we estimate the early effect of the European Monetary Union (EMU) on trade. We use a panel data set that includes the most recent information on bilateral trade for 22 developed countries from 1992 through 2002. During this period 12 European countries formally entered into a currency union. This is a unique event that allows us to study the effect of currency union among a relatively homogeneous group of industrial countries. Controlling for a host of other factors, we find that the effect of EMU on bilateral trade between member countries ranges between 5 and 10 percent, when compared to trade between all other pairs of countries, and between 9 and 20 percent, when compared to trade among non-EMU countries. In addition, we find no evidence of trade diversion. If anything, our results suggest that monetary union increases trade not just with EMU countries, but also with the rest of the world.
Solid-state photodimerization of 2-phenylethenyl enamides

Abstract Enamides 3a-c and 6 crystallize in α-packing modes with short intermolecular distances of 3.7–4.0 A between alkene carbon atoms of adjacent molecules related by a center of symmetry. Irradiation at 350 nm of these crystalline tertiary phenylethenyl enamides affords head-to-tail dimers 8a-c and 9, respectively, in 87–92% yield, in marked contrast to the E to Z isomerization that is the exclusive reaction upon solution irradiation of enamides 3a and 6.
Synthetic studies directed toward guianolides: an organoiron route to the 5,7,5 tricyclic ring system

A diastereoselective route to the 5,7,5-tricyclic core of the guianolides is presented. This route relies on Cope rearrangement of a divinylcyclopropane prepared by alkenyl Grignard addition to a (pentadienyl)iron(+1) cation, followed by oxidative decomplexation. An additional key reaction involves oxidative rearrangement of a 3,4-epoxy-1,7-diol to generate a γ-lactone. The relative stereochemistry of this product was established by X-ray crystallography.
N-Prolinylanthranilic acid derivatives as bifunctional organocatalysts for asymmetric aldol reactions

Several N-prolinylanthranilic acid derivatives were prepared and tested as bifunctional organocatalysts in the direct asymmetric aldol reaction of cyclohexanone with p-nitrobenzaldehyde. It was found that methyl substitution ortho to the carboxylic acid improves enantioselectivity, but substitution ortho to the anilide group does not. The catalyst derived from 2-amino-6-methylbenzoic acid was tested over a range of direct asymmetric aldol reactions and its overall performance is equal to or better than many of the known prolinamide catalysts in terms of yield, diastereoselectivity, and enantioselectivity.
Topological analysis of network attack vulnerability

This talk will discuss issues and methods for survivability of systems under malicious attacks. To protect from such attacks, it is necessary to take steps to prevent attacks from succeeding. At the same time, it is important to recognize that not all attacks can be averted at the outset; attacks that are successful to some degree must be recognized as unavoidable and comprehensive support for identifying and responding to attacks is required.In my talk, I will describe the recent research on attack graphs that represent known attack sequences attackers can use to penetrate computer networks. I will show how attack graphs can be used to compute actual sets of hardening measures that guarantee the safety of given critical resources. Attack graphs can also be used to correlate received alerts, hypothesize missing alerts, and predict future alerts, all at the same time. Thus, they offer a promising solution for administrators to monitor and predict the progress of an intrusion, and take appropriate countermeasures in a timely manner.
Relativistic D-brane scattering is extremely inelastic

We study the effects of quantum production of open strings on the relativistic scattering of D-branes. We find strong corrections to the brane trajectory from copious production of highly-excited open strings, whose typical oscillator level is proportional to the square of the rapidity. In the corrected trajectory, the branes rapidly coincide and remain trapped in a configuration with enhanced symmetry. This is a purely stringy effect which makes relativistic brane collisions exceptionally inelastic. We trace this effect to velocity-dependent corrections to the open string mass, which render open strings between relativistic D-branes surprisingly light. We observe that pair-creation of open strings could play an important role in cosmological scenarios in which branes approach each other at very high speeds.
A new carbon-carbon bond forming reaction in indole chemistry. C3-Arylation and alkylation with phenyl (β-indolyl) iodonium trifluoroacetate

Abstract Phenyl(β-indolyl)iodonium trifluoroacetate was reacted with various alkyl and aryllithiums (CH 3 , n -C 4 H 9 , C 3 H 5 , C 6 H 5 ) in BF 3 Et 2 O/THF to yield C 3 -alkylation and arylation of the indole nucleus with reductive elimination of iodobenzene.
A Longitudinal Study of Technological Obsolescence

(1975). A Longitudinal Study of Technological Obsolescence. Research Management: Vol. 18, No. 6, pp. 22-28.
Astrometry with Virtual Observatories

With the advent of virtual observatories, most astrometry-oriented projects being currently developed—and those to come in the near future—will be greatly enriched. Among these projects it is worth mentioning double stars and multiple systems, proper-motion detections, identification of lost high-proper-motion stars, a detailed census of open cluster members, and precovery of natural satellites, minor planets and comets. A brief discussion of some of these studies is presented. To accomplish the goals proposed by the virtual observatories concept, a massive amount of high-quality astrometric data is needed in advance. It is shown that today's astrometry is about to ready to face these new challenges.
Chern-Simons Theory, Matrix Integrals, and Perturbative Three-Manifold Invariants

The universal perturbative invariants of rational homology spheres can be extracted from the Chern-Simons partition function by combining perturbative and nonperturbative results. We spell out the general procedure to compute these invariants, and we work out in detail the case of Seifert spaces. By extending some previous results of Lawrence and Rozansky, the Chern-Simons partition function with arbitrary simply-laced group for these spaces is written in terms of matrix integrals. The analysis of the perturbative expansion amounts to the evaluation of averages in a Gaussian ensemble of random matrices. As a result, explicit expressions for the universal perturbative invariants of Seifert homology spheres up to order five are presented.
Some nonlinear response characteristics of collapsing composite shells

Conclusions This preliminary study shows the advantages of the strand in increased toughness at the expense of loss of stiffness, a characteristic quite typical of biological structures. The "design" of the latter is such that any increase in toughness is at the cost of some reduction in stiffness. Whether man-made structures can adapt this principle is an open question but is worth further examination. In so far as use of such strandlike or ropelike fibers in composites is concerned, we continue to look into the question of behavior in compression to examine buckling and bird-caging problems. Even when those issues are resolved satisfactorily, there is of course the larger question of manufacturability. Nevertheless, the concept appears attractive and deserves further scrutiny by interested researchers.
Origin of density fluctuations in extended inflation.

The density fluctuations (both curvature and isocurvature) that arise due to quantum fluctuations in a simple model of extended inflation based upon the Jordan-Brans-Dicke theory are calculated. Curvature fluctuations arise due to quantum fluctuations in the Brans-Dicke field, in general have a nonscale-invariant spectrum, and can have an amplitude that is cosmologically acceptable and interesting without having to tune any coupling constant to a very small value. The density perturbations that arise due to the inflation field are subdominant. If there are other massless fields in the theory, e.g., an axion or an ilion, then isocurvature fluctuations arise in these fields too. Production of gravitational waves and the massless particles associated with excitations of the Brans-Dicke field are also discussed. Several attempts at more realistic models of extended inflation are also analyzed. The importance of the Einstein conformal frame in calculating curvature fluctuations is emphasized. When viewed in this frame, extended inflation closely resembles slow-rollover inflation with an exponential potential and the usual formula for the amplitude of curvature perturbations applies.
Effects of type A personality and leisure ethic on Chinese college students' leisure activities and academic performance.

Abstract The purpose of the present study was to examine the effects of Type A personality and leisure ethic on students' leisure activities and academic performance. Chinese college students in the Republic of China were classified as either Type A or Type B, and as either high leisure ethic or low leisure ethic, based on the median-split in their scores on Type A and leisure ethic measures. The results of 2 × 2 analyses of variance suggested that high leisure ethic subjects had significantly higher reported frequencies of going to movies and live concerts than had low leisure ethic subjects. Type As had a significantly higher rate of going to live concerts than had Type Bs. Type As with a high leisure ethic endorsement attended more live concerts than the average of the other three groups. Type As with a low leisure ethic had a significantly better total academic performance than the average of the other three groups. For Type Bs, however, the results failed to reach significance. Individuals' Type A pe...
Enumerating Maximal Bicliques from a Large Graph Using MapReduce

We consider the enumeration of maximal bipartite cliques (bicliques) from a large graph, a task central to many data mining problems arising in social network analysis and bioinformatics. We present novel parallel algorithms for the MapReduce framework, and an experimental evaluation using Hadoop MapReduce. Our algorithm is based on clustering the input graph into smaller subgraphs, followed by processing different subgraphs in parallel. Our algorithm uses two ideas that enable it to scale to large graphs: (1) the redundancy in work between different subgraph explorations is minimized through a careful pruning of the search space, and (2) the load on different reducers is balanced through a task assignment that is based on an appropriate total order among the vertices. We show theoretically that our algorithm is work optimal, i.e., it performs the same total work as its sequential counterpart. We present a detailed evaluation which shows that the algorithm scales to large graphs with millions of edges and tens of millions of maximal bicliques. To our knowledge, this is the first work on maximal biclique enumeration for graphs of this scale.
Synthesis of phosphaformamidines and phosphaformamidinates.

A large-scale synthetic route to a variety of phosphaformamidines and phosphaformamidinates, a type of derivative that was not accessible by the methods previously known for preparing phosphaamidines and phosphaamidinates, is reported. Thermally stable ethyl N-arylformimidates 1 (ArNCH(OEt), Ar=2,4,6-(Me)3Ph or 2,6-(iPr)2Ph) readily reacted with lithium dialkyl- and diarylphosphanides to afford the corresponding N-aryl phosphaformamidines in 80 and 60 % yield, respectively, whereas with lithium (aryl)(silyl)phosphanide, the N-aryl-N-silylphosphaformamidine (60 % yield) was obtained. Addition of primary lithium arylphosphanides to 1 followed by addition of a stoichiometric amount of nBuLi gave rise to the respective phosphaformamidinates (70–88 % yield). Methanolysis of the products afforded the N-aryl-N-hydrogenophosphaformamidines (90–95 % yield). The solid-state structure of one of the phosphaformamidinates is also presented.
Constrained Relative Attitude Determination for Two-Vehicle Formations

This paper studies constrained relative attitude determination of a formation of two vehicles. A deterministic solution for the relative attitude between the two vehicles with line-of-sight measurements between them and a common object observed by both vehicles is presented. The solution represents the minimum number of measurements required to determine the relative attitudes and no ambiguities are present. To quantify the performance of the algorithm the covariance of the attitude error is derived using a linearized error model from a least-squares point of view. Simulation results are also provided to assess the performance of the proposed new approach.
The Kissing Problem: How to End a Gathering When Everyone Kisses Everyone Else Goodbye

This paper introduces the kissing problem: given a rectangular room with n people in it, what is the most efficient way for each pair of people to kiss each other goodbye? The room is viewed as a set of pixels that form a subset of the integer grid. At most one person can stand on a pixel at once, and people move horizontally or vertically. In order to move into a pixel in time step t, the pixel must be empty in time step t1. The paper gives one algorithm for kissing everyone goodbye. This paper gives optimal solutions for small cases, which were found using a heuristic state space search (IDA*).
The effects of therapy on the developmental scores of iron-deficient infants.

To test the hypothesis that iron deficiency in infants and children is associated with behavioral alterations, 24 infants with iron deficiency anemia, ages 9 to 26 months, were randomly assigned to a treatment and control group. Bayley Scales of Infant Development were administered before treatment with intramuscular iron or placebo; the test was readministered in five to eight days. Children treated with iron showed a significant increase in their scores on the Mental Development Index averaging a mean gain of 13.6 points in a mean time of 6.8 days. The treated group was also found to become more alert and responsive and demonstrated improvement in tests of gross and fine motor coordination. These findings support the hypothesis that iron deficiency in infants produces developmental alterations and that these changes are rapidly reversible with iron therapy.
Finite element analysis of an ultralight aircraft

A finite element analysis was conducted to determine the structural integrity of a high-wing cable-tsupported ultralight aircraft. A simple, symmetrical, half-structure macromodel was analyzed and subjected to level flight loading and two-wheel-landing loading conditions. Flexural and bending stiffness for the supported and unsupported wing were also determined. A preliminary damage tolerance analysis was conducted in which selected cable elements and wing compression struts were removed, the redistributed loads calculated, and possible aircraft flight configurations examined. The model can generate all cable loads, displacement of each structural node (for each loading condition), generate displacement plots, and locate potential highly stressed regions.
Force Transmission in the Actin Cytoskeleton

The actin cytoskeleton plays a crucial role in transmitting forces generated by molecular processes to cellular length scales to control the morphological and physical behaviors of cells. Force transmission from the molecular to cellular scale is well understood in the context of myosin II-mediated forces occurring in highly organized myofibrils found in striated muscle. However, diverse actomyosin organization found in non-muscle cells and utilized to effect shape change and force generation in cell adhesion, migration and division. The mechanical behaviors of such disordered actomyosin networks and bundles are not well understood. Our lab has developed approaches to study these questions by comparing quantitative biophysical measurements on live cells and in vitro reconstitutions with simulation and theory. I will discuss our recent data on force transmission in disordered actomyosin assemblies in the context of cell adhesion and migration.
Under What Conditions do Public Managers Favor and Pursue Organizational Change

Managerial leaders play a prominent role in organizational change--as champions for change and as key players in its implementation. This study seeks to understand why public managers choose to support change and initiate it within their organizations. A model of change-related attitude and behavior is developed and tested in the study. The results indicate that a complex pattern of internal and external factors influence a public manager's attitude and behavior relating to change. The results also suggest that top-down and bottom-up drivers of change work simultaneously to influence a public manager's decision to assume the role of a change agent
Angular Distributions as Lifetime Probes

If new TeV scale particles are discovered, it will be important to determine their width. There is, however, a problematic region, where the width is too small to be determined directly, and too large to generate a secondary vertex. For a collection of colored, spin polarized particles, hadronization depolarizes the particles prior to their decay. The amount of depolarization can be used to probe the lifetime in the problematic region. In this paper we apply this method to a realistic scenario of a top-like particle that can be produced at the LHC. We study how depolarization affects the angular distributions of the decay products and derive an equation for the distributions that is sensitive to the lifetime.
Na5Sn13: A New Zintl Phase with a Complex Network Structure Constructed from Tin Pentagons

The compound Na5Sn13 forms in the sodium−tin system in high yield following prolonged reaction of a quenched mixture at 280 °C in a Ta container. The compound exhibits a complex three-dimensional structure (29 independent atoms) built mainly of 4-bonded tin atoms in interbonded pentagons (orthorhombic, space group Cmcm (No. 63); a = 8.979(1) A, b = 19.448(6) A, c = 50.43(2) A, Z = 16). According to Zintl−Klemm electron-counting formalisms, the compound has a closed-shell electronic configuration with the number of 3-bonded Sn- equal to the number of sodium cations. Property measurements show that the compound is diamagnetic.
Dynamical Mass Estimates of Large-Scale Filaments in Redshift Surveys

We propose a new method to measure the mass of large-scale filaments in galaxy redshift surveys. The method is based on the fact that the mass per unit length of isothermal filaments depends only on their transverse velocity dispersion. Filaments that lie perpendicular to the line of sight may therefore have their mass per unit length measured from their thickness in redshift space. We present preliminary tests of the method and find that it predicts the mass per unit length of filaments in an N-body simulation to an accuracy of ~35%. Applying the method to a select region of the Perseus-Pisces supercluster yields a mass-to-light ratio of M/LB ≈ 450 h in solar units to within a factor of 2. The method measures the mass-to-light ratio on mass scales up to 10 times that of clusters of galaxies and could thereby yield new information on the behavior of the dark matter on large scales.
Distortion of globular clusters by galactic bulges

One of the external fields that influences the population of globular clusters is that resulting from galactic bulges. In extreme situations, at perigalactic distances rp≤ 100 pc, globular clusters could suffer total disruption in a single passage. A more common scenario is that for cluster orbits with rp≥ 200 pc. We investigate the effects of tidal forces from a bulge on the shape of globular clusters for this type of encounter. We find distortions characterized by `twisting isophotes' and consider the potential for observability of this effect. In the Milky Way, a typical globular cluster must pass within several hundred pc of the centre to experience substantial distortion, and it is possible that this has happened recently to one or two present-day clusters. We estimate that this distortion could be observed even for globulars in dense fields towards the bulge. In more extreme environments such as giant ellipticals or merger products with newly formed globulars, this effect could be more common, extending out to orbits that pass within 1 kpc of the bulge centre. This would lead to a substantial shift in the eccentricity distribution of globulars in those galaxies.
Malignant tumors of the nasal cavity and paranasal sinuses.

Purpose To evaluate the role of radiation therapy in patients with nasal cavity and paranasal sinus tumors. Materials and Methods Between October 1964 and July 1998, 78 patients with malignant tumors of the nasal cavity (48 patients), ethmoid sinus (24 patients), sphenoid sinus (5 patients), or frontal sinus (1 patient) were treated with curative intent by radiation therapy alone or in the adjuvant setting. There were 25 squamous cell carcinomas, 14 undifferentiated carcinomas, 31 minor salivary gland tumors (adenocarcinoma, adenoid cystic carcinoma, and mucoepidermoid carcinoma), 8 esthesioneuroblastomas, and 1 transitional cell carcinoma. Forty-seven patients were treated with irradiation alone, 25 with surgery and postoperative irradiation, 2 with preoperative irradiation and surgery, and 4 with chemotherapy in combination with irradiation with or without surgery. Results The 5-year actuarial local control rate for stage I (limited to the site of origin; 22 patients) was 86%; for stage II (extension to adjacent sites (eg, adjacent sinuses, orbit, pterygomaxillary fossa, nasopharynx; 21 patients) was 65%; and for stage III (destruction of skull base or pterygoid plates, or intracranial extension; 35 patients) was 34%. The 5-year actuarial local control rate for patients receiving postoperative irradiation was 79% and for patients receiving irradiation alone was 49% (p = .05). The 5-, 10-, 15-, and 20-year ultimate local control rates for all 78 patients were 60%, 56%, 48%, and 48%, respectively. The 5-, 10-, 15-, and 20-year cause-specific survival rates for all 78 patients were 56%, 45%, 39%, and 39%, respectively. The 5-, 10-, 15-, and 20-year absolute survival rates for all 78 patients were 50%, 31%, 21%, and 16%, respectively. Of the 67 (86%) patients who were initially seen with node-negative disease, 39 (58%) received no elective neck treatment, and 28 (42%) received elective neck irradiation. Of the 39 patients who received no elective neck treatment, 33 (85%) did not experience recurrence in the neck compared with 25 (89%) of 28 patients who received elective neck irradiation. Most patients who received elective neck irradiation (57%) had stage III disease. Twenty-one (27%) of 78 patients had unilateral blindness develop secondary to radiation retinopathy or optic neuropathy; the complication was anticipated in most of these patients, because the ipsilateral eye was irradiated to a high dose. Four patients (5%) unexpectedly had bilateral blindness develop because of optic neuropathy. All four of these patients received irradiation alone. Conclusion Surgery and postoperative radiation therapy may result in improved local control, absolute survival, and complications when compared with radiation therapy alone. Elective neck irradiation is probably unnecessary for patients with early-stage disease. © 2002 Wiley Periodicals, Inc. Head Neck 24: 821–829, 2002
Use of replicated Latin hypercube sampling to estimate sampling variance in uncertainty and sensitivity analysis results for the geologic disposal of radioactive waste

Abstract The 2008 performance assessment (PA) for the proposed repository for high-level radioactive waste at Yucca Mountain (YM), Nevada, used a Latin hypercube sample (LHS) of size 300 in the propagation of the epistemic uncertainty present in 392 analysis input variables. To assess the adequacy of this sample size, the 2008 YM PA was repeated with three independently generated (i.e., replicated) LHSs of size 300 from the indicated 392 input variables and their associated distributions. Comparison of the uncertainty and sensitivity analysis results obtained with the three replicated LHSs showed that the three samples lead to similar results and that the use of any one of three samples would have produced the same assessment of the effects and implications of epistemic uncertainty. Uncertainty and sensitivity analysis results obtained with the three LHSs were compared by (i) simple visual inspection, (ii) use of the t-distribution to provide a formal representation of sample-to-sample variability in the determination of expected values over epistemic uncertainty and other distributional quantities, and (iii) use of the top down coefficient of concordance to determine agreement with respect to the importance of individual variables indicated in sensitivity analyses performed with the replicated samples. The presented analyses established that an LHS of size 300 was adequate for the propagation and analysis of the effects and implications of epistemic uncertainty in the 2008 YM PA.
A solution to the lower dimensional Busemann-Petty problem in the hyperbolic space

The lower dimensional Busemann-Petty problem asks whether origin symmetric convex bodies in ℝn with smaller volume of all k-dimensional sections necessarily have smaller volume. As proved by Bourgain and Zhang, the answer to this question is negative if k>3. The problem is still open for k = 2, 3. In this article we formulate and completely solve the lower dimensional Busemann-Petty problem in the hyperbolic space ℍn.
A nonsmooth program for jamming hard spheres

We study packings of $$n$$ hard spheres of equal radius in the $$d$$ -dimensional unit cube. We present a nonsmooth function whose local extrema are the radii of jammed packings (where no subset of spheres can be moved keeping all others fixed) and show that for a fixed number of spheres there are only finitely many radii of such jammed configurations. We propose an algorithm for the maximization of this maximal radius function and present examples for five to eight disks in the unit square and four to six spheres in the unit cube. The method allows straightforward generalization to packings of spheres in other compact containers.
Correlation of Zeno (Z = 1) line for supercritical fluids with vapor-liquid rectilinear diameters

For a wide range of substances, extending well beyond the regime of corresponding states behavior, the contour in the temperature-density plane along which the compressibility factor Z = P/{rho}kT is the same as for an ideal gas is nearly linear. This Z = 1 contour, termed the Zeno line, begins deep in the liquid region and ascends as the density decreases to the Boyle point of the supercritical fluid, specified by the temperature T{sub B} for which (dZ/d{rho}){sub T} = 0 as {rho} {r_arrow} 0; equivalent, at T{sub B} the second virial coefficient vanishes. The slope of the Z = 1 line is {minus}B{sub 3}/(dB{sub 2}/dT), in terms of the third virial coefficient and the derivative of the second, evaluated at T{sub B}. Previous work has examined the Zeno line as a means to extend corresponding states and to enhance other practical approximations. Here the authors call attention to another striking aspect, a strong correlation with the line of rectilinear diameters defined by the average of the subcritical vapor and liquid densities. This correlation is obeyed well by empirical data for many substances and computer simulations for a Lennard-jones potential; the ratios of the intercepts and slopes for the Zenomore » and rectilinear diameter liens are remarkably close to those predicted by the van der Waals equation, 8/9 and 16/9, respectively. Properties of the slightly imperfect fluid far above the critical point thus implicitly determine the diameter of the vapor-liquid coexistence curve below the critical point.« less
Electron-phonon coupling in a two-dimensional inhomogeneous electron gas : consequences for surface spectral properties

We investigate the coupling of an inhomogeneous electron system to phonons. The properties of an electronic system composed of a mixture of microscopic ordered and disordered islands are changed fundamentally by a phonon mode. In high-Tc cuprates, such a phase separation scenario is supported by recent STM and nuclear quadrupole resonance studies. We show that even a weak or moderate electron–phonon coupling can be sufficient to produce dramatic changes in the electronic state of the inhomogeneous electron gas. The spectral properties calculated in our approach provide a natural explanation of the low-energy nodal ARPES features and exhibit a novel non-Fermi-liquid state stabilized through electron–phonon coupling.
Quantum corrections in collective field theory

Abstract We review and extend the computation of scattering amplitudes of tachyons in the c = 1 matrix model using a manifestly finite prescription for the collective field hamiltonian. We give further arguments for the exactness of the cubic hamiltonian by demonstrating the equality of the loop corrections in the collective field theory with those calculated in the fermionic picture.
Distributed collaborative environments for systems engineering

Distributed collaboration is an emerging technology for the 21/sup st/ century that will significantly change how business is conducted In the defense and commercial sectors. Collaboration involves two or more geographically dispersed individuals working together to create a "product" by sharing and exchanging data, information, and knowledge. A product is defined broadly to Include, for example, writing a report, creating software, designing hardware, or implementing robust systems engineering processes In an organization. Collaborative environments provide the framework and Integrate models, simulations, domain specific tools, and virtual test beds to facilitate collaboration between the multiple disciplines needed in the enterprise. The Air Force Research Laboratory (AFRL) Is conducting a leading edge program in developing distributed collaborative technologies targeted to the Air Force's implementation of systems engineering for simulation-aided acquisition and test process and capability-based planning. The research Is focusing on the open systems agent-based framework, product and process modeling, structural architecture, and the integration technologies - the glue to integrate the software components. In past four years, two live assessment events have been conducted to demonstrate the technology in support of Air Force Agile Acquisition that included capabilities for system engineering. The AFRL Collaborative Environment concept will foster a major cultural change In how the acquisition, training, and operational communities conduct business.
A generalized object display processor architecture

The features and organization of a hardware architecture that is designed to facilitate the real-time display and manipulation of a single three-dimensional object on a raster-scan video display are briefly summarized. The author then outlines the major features of an extension to the architecture that will permit the high-speed display and manipulation of multiple, independent, shaded three-dimensional objects represented as a voxel (volume-element) database with gray scale. The objective is to provide many useful capabilities at or near video rates facilitating extensive real-time interaction. The architecture is highly modular, permitting a cost tradeoff to be made to achieve a given level of performance. It also includes a great deal of regularity in its structure, making it directly suitable for VLSI implementation. A key feature is that no computational operations more complex than adds, shifts, and comparisons are required in real time. The display characteristics for each object are controlled by a concise object descriptor table, which contains all of the control parameters required to process that object.