cssi/SciSciGPT-SciSciNet huggingface dataset:
Parallel Successive Convex Approximation for Nonsmooth Nonconvex Optimization

Consider the problem of minimizing the sum of a smooth (possibly non-convex) and a convex (possibly nonsmooth) function involving a large number of variables. A popular approach to solve this problem is the block coordinate descent (BCD) method whereby at each iteration only one variable block is updated while the remaining variables are held fixed. With the recent advances in the developments of the multi-core parallel processing technology, it is desirable to parallelize the BCD method by allowing multiple blocks to be updated simultaneously at each iteration of the algorithm. In this work, we propose an inexact parallel BCD approach where at each iteration, a subset of the variables is updated in parallel by minimizing convex approximations of the original objective function. We investigate the convergence of this parallel BCD method for both randomized and cyclic variable selection rules. We analyze the asymptotic and non-asymptotic convergence behavior of the algorithm for both convex and non-convex objective functions. The numerical experiments suggest that for a special case of Lasso minimization problem, the cyclic block selection rule can outperform the randomized rule.
Pixel scaling in infrared focal plane arrays

We discuss effects that arise in pixels of IR focal plane arrays (FPAs) when pixel size scales down to approach the wavelength of the incident radiation. To study these effects, we perform first-principles electromagnetic simulations of pixel structures based on a mercury–cadmium–telluride photoconductor for use in FPAs. Specifically, we calculate the pixel quantum efficiency and crosstalk as pixel size scales from 16 μm, which is in the range of current detectors, down to 0.75 μm, corresponding to subwavelength detectors. Our numerical results indicate the possibility of wavelength-size (∼4 μm) and even subwavelength-size (∼1 μm) pixels for IR FPAs. In addition, we explore opportunities that emerge for controlling light with subwavelength structures inside FPA pixels. As an illustration, we find that the low-pass filtering effect of a metal film aperture can exemplify the impact and the possible role that wavelength-scale optics plays in very small pixels.
A complete model of low-scale gauge mediation

Recent signs of a Standard Model-like Higgs at 125 GeV point towards large A-terms in the MSSM. This presents special challenges for gauge mediation, which by itself predicts vanishing A-terms at the messenger scale. In this paper, we review the general problems that arise when extending gauge mediation to achieve large A-terms, and the mechanisms that exist to overcome them. Using these mechanisms, we construct weakly-coupled models of low-scale gauge mediation with extended Higgs-messenger couplings that generate large A-terms at the messenger scale and viable μ/B μ -terms. Our models are simple, economical, and complete realizations of supersymmetry at the weak scale.
A computer-based productivity and quality management system for cellular manufacturing

An integrated computer-based system which supports the technical and social requirements of cellular manufacturing was designed, developed and implemented at an ailing aircraft component manufacturer to improve productivity and quality. Major challenges faced by the plant included a maturing workforce, excessive scrap, rework, lack of coordination, poor delivery performance, and a general lack of technical processes and product understanding. Processes were out of control and as a result, productivity and quality suffered. This developmental case illustrates the need for a sociotechnical systems approach to cellular manufacturing, where personnel and technological requirements are jointly met.
Identity, Contingency and Rigidity. The (counter-)hegemonic constructions of the identity of the media professional

This article uses key notions of the discourse theory of Laclau and Mouffe to analyze the identity of the media professional. Within their post-structural framework, this identity is seen as over-determined, contingent and constructed but at the same time subjected to a hegemonic articulation, based on four nodal points: objectivity, autonomy, management of resources and employee-employer relations. Combined with a theoretical discussion on the (counter-)hegemonic articulations, this allows for the field of discursivity that surrounds the identity of the media professional to be (re)constructed, resulting in four dimensions that offer potential points of identification. This field of discursivity is then used and put to the test as a series of sensitizing concepts for the analysis of the seven phone-in broadcasts the program Ter Zake (on VRT - the North Belgian public broadcasting company) has organized, illustrating both the contingency of the identity of the media professional and the rigidity of the he...
On integral sum graphs

A graph G is said to be an integral sum graph if its nodes can be given a labeling f with distinct integers, so that for any two distinct nodes u and v of G, uv is an edge of G if and only if f(u)+f(v)=f(w) for some node w in G. A node of G is called a saturated node if it is adjacent to every other node of G. We show that any integral sum graph which is not K"3 has at most two saturated nodes. We determine the structure for all integral sum graphs with exactly two saturated nodes, and give an upper bound for the number of edges of a connected integral sum graph with no saturated nodes. We introduce a method of identification on constructing new connected integral sum graphs from given integral sum graphs with a saturated node. Moreover, we show that every graph is an induced subgraph of a connected integral sum graph. Miscellaneous related results are also presented.
Mass transport in chalcogenide electrolyte films - materials and applications

Certain metals can be added to thin films of chalcogenide glasses by photodissolution to create materials with unique morphology and properties. When Ag is combined in this fashion with Ge–Se or Ge–S glasses, the resulting ternary contains a dispersed nanocrystalline Ag2S(e) phase that has large quantities of mobile metal ions. The presence of these ions allows the ternaries to act as solid electrolytes. If an anode which has an oxidizable form of the ionic metal and an inert cathode are applied in contact with such a phase-separated electrolyte, an ion current can flow under an applied bias in excess of a few hundred millivolt. Electrons from the cathode reduce the excess metal due to the ion flux and an electrodeposit forms on or in the electrolyte. Utilizing this effect, we developed programmable metallization cell (PMC) technology which offers new functionality for such materials. Based on mass transport driven by electrochemical processes, PMC technology may be applied in solid state electronics, integrated optics, microelectromechanical systems (MEMS), and microfluidics. This paper is a review of the unique materials aspects of thin film solid electrolytes formed by photodissolution of metal into a chalcogenide base glass and the demonstrated applications of this technology.
Information, School Choice, and Academic Achievement: Evidence from Two Experiments

We examine a natural experiment and a field experiment that provided direct information on school test scores to lower-income families in a public school choice plan. Receiving information significantly increases the fraction of parents choosing higher-performing schools. Parents with high-scoring alternatives nearby were more likely to choose nonguaranteed schools with higher test scores. Using random variation from each experiment, we find that attending a higher-scoring school increases student test scores. The results imply that school choice will most effectively increase academic achievement for disadvantaged students when parents have easy access to test score information and good options from which to choose.
Who Gets on Top in Democracy - Elections as Filters

Economic models of politics usually assume that all politicians maximize their narrow self-interest, so the constitution and other laws should be designed to constrain the worst people. In contrast, I assume that different politicians have different traits of character, so the constitution and other laws should be designed to promote the best and demote the worst. Successful filtering of politicians partly determines whether a country enjoys good or bad government. In my model, each election serves as a filter, so, up to a point, more elections filter better. Countries that suffer bad government do so partly because politicians face too few elections for the citizens to identify the worst characters and remove them from office. These countries, however, should not necessarily shorten the term of office in order to have more frequent elections. Rather, these countries should reduce the depth of administration and create a federal structure with more elected governments. Similarly, these countries should ti...
Expression of P63 in Primary Cutaneous Adnexal Neoplasms and Adenocarcinoma Metastatic to the Skin

p63, a recently identified homologue of p53 gene, has been reported to be essential in the development of epithelia and is mainly expressed by basal and myoepithelial cells. The purpose of this study was to investigate the pattern of p63 expression in cutaneous adnexal neoplasms and to assess its possible value in the differential diagnosis of primary cutaneous neoplasms versus adenocarcinomas metastatic to the skin. Immunohistochemical analysis using p63 monoclonal antibody (clone 4A4) was performed on formalin-fixed, paraffin-embedded archival tissue from 20 benign adnexal tumors, 10 malignant adnexal tumors, and 14 adenocarcinomas metastatic to the skin. The expression of p63 was evaluated in epidermal cells, skin appendages and metastatic tumor cells. p63 was consistently expressed in the basal/suprabasal cells of epidermis and cutaneous appendages, including the basal/myoepithelial cells of sweat glands. Thirteen out of 20 (65%) benign adnexal tumors showed strong p63 expression; the remaining 7(35%) cases had over 50% p63-positive nuclei. All primary cutaneous carcinomas, including adenocarcinomas, expressed p63. In contrast, none of the metastatic adenocarcinomas to the skin was positive for p63 (p < 0.0001). Based on our findings, analysis of p63 expression may be a helpful tool in the differential diagnosis of primary versus metastatic cutaneous adenocarcinomas.
Indentation of Ceramics with Spheres: A Century after Hertz

In this article we review the nature and mechanics of damage induced in ceramics by spherical indenters, from the classical studies of Hertz over a century ago to the present day. Basic descriptions of continuum elastic and elastic-plastic contact stress fields are first given. Two distinct modes of damage are then identified: Hertzian cone cracks, in relatively hard, homogeneous materials, such as glasses, single crystals, fine-grain ceramics (tensile, brittle mode); and diffuse subsurface damage zones, in relatively tough ceramics with heterogeneous microstructures (shear, quasi-plastic mode). Ceramographic evidence is presented for the two damage types in a broad range of materials, illustrating how an effective brittle-ductile transition can be engineered by coarsening and weakening the grain structure. Continuum analyses for cone fracture and quasi plasticity, using Griffith-Irwin fracture mechanics and yield theory, respectively, are surveyed. Recent micromechanical models of the quasi-plastic mode are also considered, in terms of grain-localized shear faults with extensile wing cracks. The effect of contact-induced damage on the ensuing strength properties of both brittle and quasi-plastic ceramics is examined. Whereas cone cracking causes abrupt losses in strength, the effect of quasi-plastic damage is more gradual-so that more heterogeneous ceramics are more damage tolerant. On the other hand, quasi-plastic ceramics are subject to accelerated strength losses in extreme cyclic conditions (contact fatigue), because of coalescence of attendant microcracks, with implications concerning wear resistance and machinability. Extension of Hertzian contact testing to novel layer structures with hard, brittle outer layers and soft, tough underlayers, designed to impart high toughness while preserving wear resistance, is described.
Shelf Circulation and Cross-Shelf Transport out of a Bay Driven by Eddies from an Open-Ocean Current. Part I: Interaction between a Barotropic Vortex and a Steplike Topography

AbstractThis paper examines interaction between a barotropic point vortex and a steplike topography with a bay-shaped shelf. The interaction is governed by two mechanisms: propagation of topographic Rossby waves and advection by the forcing vortex. Topographic waves are supported by the potential vorticity (PV) jump across the topography and propagate along the step only in one direction, having higher PV on the right. Near one side boundary of the bay, which is in the wave propagation direction and has a narrow shelf, waves are blocked by the boundary, inducing strong out-of-bay transport in the form of detached crests. The wave–boundary interaction as well as out-of-bay transport is strengthened as the minimum shelf width is decreased. The two control mechanisms are related differently in anticyclone- and cyclone-induced interactions. In anticyclone-induced interactions, the PV front deformations are moved in opposite directions by the point vortex and topographic waves; a topographic cyclone forms out ...
Call and response: experiments in sampling the environment

Monitoring of environmental phenomena with embedded networked sensing confronts the challenges of both unpredictable variability in the spatial distribution of phenomena, coupled with demands for a high spatial sampling rate in three dimensions. For example, low distortion mapping of critical solar radiation properties in forest environments may require two-dimensional spatial sampling rates of greater than 10 samples/m2 over transects exceeding 1000 m2. Clearly, adequate sampling coverage of such a transect requires an impractically large number of sensing nodes. This paper describes a new approach where the deployment of a combination of autonomous-articulated and static sensor nodes enables sufficient spatiotemporal sampling densityo ver large transects to meet a general set of environmental mapping demands.To achieve this we have developed an embedded networked sensor architecture that merges sensing and articulation with adaptive algorithms that are responsive to both variabilityin environmental phenomena discovered bythe mobile sensors and to discrete events discovered byst atic sensors. We begin byde scribing the class of important driving applications, the statistical foundations for this new approach, and task allocation. We then describe our experimental implementation of adaptive, event aware, exploration algorithms, which exploit our wireless, articulated sensors operating with deterministic motion over large areas. Results of experimental measurements and the relationship among sampling methods, event arrival rate, and sampling performance are presented.
APPLICATION OF THE 2-AZAALLYL ANION CYCLOADDITION METHOD TO AN ENANTIOSELECTIVE TOTAL SYNTHESIS OF (+)-COCCININE

A highly functionalized perhydroindole is formed by the intramolecular [π4s+π2s] cycloaddition of a 2-azaallyl anion with a vinyl sulfide [Eq. (a)]. This is the key step in the total synthesis of (+)-coccinine, the enantiomer of the Amaryllidaceae alkaloid (-)-coccinine.
A fast higher-order time-domain finite element-boundary integral method for 3-D electromagnetic scattering analysis

A novel hybrid time-domain finite element-boundary integral method for analyzing three-dimensional (3-D) electromagnetic scattering phenomena is presented. The method couples finite element and boundary integral field representations in a way that results in a sparse system matrix and solutions that are devoid of spurious modes. To accurately represent the unknown fields, the scheme employs higher-order vector basis functions defined on curvilinear tetrahedral elements. To handle problems involving electrically large objects, the multilevel plane-wave time-domain algorithm is used to accelerate the evaluation of the boundary integrals. Numerical results demonstrate the accuracy and versatility of the proposed scheme.
Least-cost control of agricultural nutrient contributions to the Gulf of Mexico hypoxic zone

In 2008, the hypoxic zone in the Gulf of Mexico, measuring 20 720 km2, was one of the two largest reported since measurement of the zone began in 1985. The extent of the hypoxic zone is related to nitrogen and phosphorous loadings originating on agricultural fields in the upper Midwest. This study combines the tools of evolutionary computation with a water quality model and cost data to develop a trade-off frontier for the Upper Mississippi River Basin specifying the least cost of achieving nutrient reductions and the location of the agricultural conservation practices needed. The frontier allows policymakers and stakeholders to explicitly see the trade-offs between cost and nutrient reductions. For example, the cost of reducing annual nitrate-N loadings by 30% is estimated to be US$1.4 billion/year, with a concomitant 36% reduction in P and the cost of reducing annual P loadings by 30% is estimated to be US$370 million/year, with a concomitant 9% reduction in nitrate-N.
Charmed spectroscopy from a nonperturbatively determined relativistic heavy quark action in full QCD

We present a preliminary calculation of the charmed meson spectrum using the 2+1 flavor domain wall fermion lattice configurations currently being generated by the RBC and UKQCD collaborations. The calculation is performed using the 3-parameter, relativistic heavy quark action with nonperturbatively determined coefficients. We will also demonstrate a step-scaling procedure for determining these coefficients nonperturbatively using a series of quenched, gauge field ensembles generated for three different lattice spacings.
On the Nuclear Norm and the Singular Value Decomposition of Tensors

Finding the rank of a tensor is a problem that has many applications. Unfortunately, it is often very difficult to determine the rank of a given tensor. Inspired by the heuristics of convex relaxation, we consider the nuclear norm instead of the rank of a tensor. We determine the nuclear norm of various tensors of interest. Along the way, we also do a systematic study various measures of orthogonality in tensor product spaces and we give a new generalization of the singular value decomposition to higher-order tensors.
Absolute stability criteria for multiple slope-restricted monotonic nonlinearities

Absolute stability criteria such as the classical Popov criterion guarantee stability for a class of sector-bounded nonlinearities. Although the sector restriction bounds the admissible class of the nonlinearities, the local slope of the nonlinearity may be arbitrarily large. In this paper the authors derive absolute stability criteria for multiple slope-restricted time-invariant monotonic nonlinearities. Like the Popov criterion, in the single-input/single-output case the authors' results provide a simple graphical interpretation involving a straight line in a modified Popov plane. >
Counseling patients exposed to ionizing radiation during pregnancy

Health physicists and knowledgeable clinicians have the responsibility to counsel women of reproductive age about the reproductive risks of ionizing radiation exposure before conception or during pregnancy. It is important to realize that lay individuals have many misconceptions about the reproductive risks of ionizing radiation. Many patients who have already had or will undergo some type of radiological test are apprehensive about the reproductive and developmental risks of diagnostic radiological procedures. Epidemiological studies and animal studies indicate that high exposures of ionizing radiation can cause miscarriage, congenital malformations, growth retardation, stillbirth, and cancer. With the exception of cancer, there are threshold exposures for those outcomes, with exposures below certain radiation doses not increasing the reproductive or developmental risks. The threshold exposure for birth defects at the most sensitive stage of development is 0.2 Gy, and the threshold for growth retardation and miscarriage is even higher. However, embryonic loss can occur from low exposures during the preimplantation and presomite stages of development ("the all or none period"). This is a stage when the embryo is more likely to die than survive malformed. The most sensitive period for the induction of mental retardation is from the 8th week to the 15th week of gestation. The threshold for deterministic effects increases after early organogenesis and also as the exposure is protracted, e.g., with radionuclides or multiple radiological procedures. Awareness that the threshold dose for developmental effects increases as the fetus develops complicates counseling because we do not have definitive data on threshold exposures at all stages of gestation. Ionizing radiation exposures prior to pregnancy represent a very low risk for the increased incidence of genetic disease in the offspring of the parents who have had radiation exposures to the ovary or testes. Counseling patients requires knowledge of embryology, genetics, radiation teratology, and the principles of teratology in order for the counselor to provide sympathetic, accurate, scholarly advice.
Rational Ignorance at the Patent Office

It is common to assert that the Patent and Trademark Office does a bad job of examining patents, and that it should spend more time and money weeding out bad patents. In this article, Professor Lemley challenges that conventional wisdom. Using available data regarding the cost and incidence of patent prosecution, litigation, licensing and other uses of patents, he demonstrates that strengthening the examination process is not cost effective. The core insight is that very few patents are actually litigated or licensed; most simply sit on a shelf unused, or are used only for noncontroversial purposes like financing. Because of this, society would be better off spending its resources in a more searching judicial inquiry into validity in those few cases in which it matters than paying for a more protracted examination of all patents ex ante. In economic terms, the patent office is rationally ignorant of the objective validity of the patents it issues.
Optimal Capacity Overbooking for the Regular Treatment of Chronic Conditions

Patients suffering from a chronic condition often require periodic treatment. For example, patients with End-Stage Renal Disease (ESRD) require dialysis three times a week. These patients are also frequently hospitalized for complications from their treatment, resulting in idle capacity at the clinic. These temporary patient absences make overbooking at the clinic attractive. This paper develops a semiclosed migration network to capture patient flow into the clinic and between the clinic and hospital. We consider a simple class of stationary control policies for patient admissions and provide algorithms for selecting one that maximizes long-run average earnings. Local diffusion approximations were constructed to provide square-root loading formulas for the optimal capacity level and patient overbooking level: as the total patient arrival rate increases, the deviation between the optimal and fluid-limit capacity and overbooking levels scale up with the square root of the total arrival rate. We find that high hospitalization rates and long inpatient stays allow for more overbooking. Numerical examples based on the typical dialysis clinic in the United States suggest an increase in earnings of 11%--14% over policies derived from traditional M/M/N models that do not account for hospitalizations and do not allow overbooking, while keeping the probability of capacity shortage arbitrarily small.
A Scale Analysis Based Theoretical Force Balance Model for Critical Heat Flux (CHF) During Saturated Flow Boiling in Microchannels and Minichannels

Accurate prediction of critical heat flux (CHF) in microchannels and minichannels is of great interest in estimating the safe operational limits of cooling systems employing flow boiling. Scale analysis is applied to identify the relevant forces leading to the CHF condition. Using these forces, a local parameter model is developed to predict the flow boiling CHF. The theoretical model is an extension of an earlier pool boiling CHF model and incorporates force balance among the evaporation momentum, surface tension, inertia, and viscous forces. Weber number, capillary number, and a new nondimensional group introduced earlier by Kandlikar (2004, "Heat Transfer Mechanisms During Flow Boiling in Microchannels, " ASME J. Heat Transfer, 126, pp. 8―16), K 2 , representing the ratio of evaporation momentum to surface tension forces, emerged as main groups in quantifying the narrow channel effects on CHF. The constants in the model were calculated from the available experimental data. The mean error with ten data sets is 19.7% with 76% data falling within ±30% error band and 93% within ±50% error band. The length to diameter ratio emerged as a parameter indicating a stepwise regime change. The success of the model indicates that flow boiling CHF can be modeled as a local phenomenon and the scale analysis is able to reveal important information regarding fundamental mechanisms leading to the CHF condition.
Use of digital front-end electronics for optimization of a modular PET detector

The sensitivity and resolution of a new 3D modular BGO detector system for positron emission tomography (PET) was examined in terms of its effect on the signal to noise ratio in the final image. The detector system uses custom hardware and firmware to adjust sensitivity and resolution to achieve optimum performance. This system utilizes lookup up tables (LUT) containing individually tailored positioning and energy windows to assure that events are correctly distributed among the detector elements. Without customizing the LUT, and for a common energy window, sensitivity was found to vary as much as a factor of 3.5 and resolution as much as 50% from center to edge within a single detector module. Eight different LUT configurations were tested, varying both energy window and positioning criteria. Typical intrinsic resolutions and sensitivities of the detector elements were determined in all configurations. The effect of nonuniformity of sensitivity of the detector system on image noise was evaluated by imaging uniform cylinders over a wide range of accumulated events. The effect of counting statistics in the measurement of detector sensitivities for the normalization of sinogram data was determined independently. The best of the LUT configurations provided an 16% improvement in effective sensitivity, while also providing a 10% improvement in the average intrinsic spatial resolution relative to the default configuration of the PET system. >
Dealing with blocking in supervisory control of discrete-event systems

The issue of blocking in the context of a general supervisory control problem with blocking which was introduced in a previous work is studied. The admissible solutions of this problem are characterized, and their properties are analyzed. Strategies to improve the performance of a given blocking supervisor are discussed. Performance is characterized in terms of two sets called the satisficing measure and the blocking measure. Techniques for improving each of these two conflicting measures are presented. Techniques to improve both measures successively in order to optimize a given supervisor are presented. >
The effects of temperature, humidity, and barometric pressure on short-sprint race times

A numerical model of 100 m and 200 m world class sprinting performances is modified using standard hydrodynamic principles to include effects of air temperature, pressure, and humidity levels on ae...
K-factors in parton cascades at RHIC and SPS

Abstract Different treatments for the inclusion of higher-order perturbative QCD corrections in parton based transport models of relativistic heavy-ion collisions are studied and their influence on experimental observables is investigated. At RHIC, particle multiplicities may vary by more than 30%, depending on the correction scheme. A detailed analysis of the squared relative momentum transfers Q2 to be expected in parton (re)scatterings at RHIC casts doubt on the applicability of pQCD based transport approaches at the SPS and rules out the application of higher-order correction schemes based on a rescaling of Q2 in the running coupling constant αs at all energies.
Aero-Optic Effects of a Wing Tip Vortex

For an airborne optical system carried by a helicopter, aero-optic aberrations originate primarily from blade tip vortices that pass through the system field of view; these aberrations result from the reduced pressure and density in the vortex cores and the associated variations in the index-of-refraction. Using the weakly compressible model (WCM) previously developed at Notre Dame, aero-optic effects for realistic tip-vortex flows are computed using the Lamb-Oseen vortex model as well as experimental velocity fields, and compared to measured wavefronts. Scaling relations are developed that enable the prediction of the aero-optic aberrations for full-scale flight vehicles.
Designing Router Scheduling Policies: A Privacy Perspective

We study the privacy compromise due to a queuing side channel which arises when a resource is shared between two users in the context of packet networks. The adversary tries to learn about the legitimate user's activities by sending a small but frequent probe stream to the shared resource (e.g., a router). We show that for current frequently used scheduling policies, the waiting time of the adversary is highly correlated with traffic pattern of the legitimate user, thus compromising user privacy. Through precise modeling of the constituent flows and the scheduling policy of the shared resource, we develop a dynamic program to compute the optimal privacy preserving policy that minimizes the correlation between user's traffic and adversary's waiting times. While the explosion of state-space for the problem prohibits us from characterizing the optimal policy, we derive a suboptimal policy using a myopic approximation to the problem. Through simulation results, we show that indeed the suboptimal policy does very well in the high traffic regime. Adapting the intuition from the myopic policy, we propose scheduling policies that demonstrate good tradeoff between privacy and delay in the low and medium traffic regime as well.
Comparative analysis of push-pull query strategies for wireless sensor networks

We present a comparative mathematical analysis of two important distinct approaches to hybrid push-pull querying in wireless sensor networks: structured hash-based data-centric storage (DCS) and the unstructured comb-needle (CN) rendezvous mechanism. Our analysis yields several interesting insights. For ALL-type queries pertaining to information about all events corresponding to a given attribute, we examine the conditions under which the two approaches outperform each other in terms of the average query and event rates. For the case of ANY-type queries where it is sufficient to obtain information from any one of the desired events for a given attribute, we propose and analyze a modified sequential comb-needle technique (SCN) to compare with DCS. We find that DCS generally performs better than CN/SCN for high query rates and low event rates, while CN/SCN perform better for high event rates. Surprisingly, for the cases of ALL-type aggregated queries and ANY-type queries, we find that there exist “magic number” event rate thresholds, independent of network size or query probability, which dictate the choice of querying protocol. While our analysis is based on a single-sink square-grid deployment, we believe the insights can be generalized to random deployments.
Metabolic futile cycles and their functions: a systems analysis of energy and control

It has long been hypothesised that futile cycles in cellular metabolism are involved in the regulation of biochemical pathways. Following the work of Newsholme and Crabtree, a quantitative theory was developed for this idea based on open-system thermodynamics and metabolic control analysis. It is shown that the stoichiometric sensitivity of an intermediary metabolite concentration with respect to changes in steady-state flux is governed by the effective equilibrium constant of the intermediate formation, and the equilibrium can be regulated by a futile cycle. The direction of the shift in the effective equilibrium constant depends on the direction of operation of the futile cycle. High stoichiometric sensitivity corresponds to ultrasensitivity of an intermediate concentration to net flow through a pathway; low stoichiometric sensitivity corresponds to super-robustness of concentration with respect to changes in flux. Both cases potentially play important roles in metabolic regulation. Futile cycles actively shift the effective equilibrium by expending energy; the magnitude of changes in effective equilibria and sensitivities is a function of the amount of energy used by a futile cycle. This proposed mechanism for control by futile cycles works remarkably similar to kinetic proofreading in biosynthesis. The sensitivity of the system is also intimately related to the rate of concentration fluctuations of intermediate metabolites. The possibility of different roles for the two major mechanisms within cellular biochemical regulation, namely reversible chemical modifications via futile cycles and shifting equilibrium by macromolecular binding, are discussed.
Generalized Cut-Set Bounds for Broadcast Networks

An explicit characterization of the capacity region of the general network coding problem is one of the best known open problems in information theory. A simple set of bounds that is often used in the literature to show that certain rate tuples are infeasible are based on the graph-theoretic notion of cut. The standard cut-set bounds, however, are known to be loose in general when there are multiple messages to be communicated in the network. This paper focuses on broadcast networks, for which the standard cut-set bounds are closely related to union as a specific set operation to combine different simple cuts of the network. A new set of explicit network coding bounds, which combine different simple cuts of the network via a variety of set operations (not just the union), are established via their connections to extremal inequalities for submodular functions. The tightness of these bounds are demonstrated via applications to combination networks.
Phase separation of saturated and mono-unsaturated lipids as determined from a microscopic model

A molecular model is proposed of a bilayer consisting of fully saturated dipalmitoylphosphatidylcholine (DPPC) and mono-unsaturated dioleoylphosphatidylcholine (DOPC). The model not only encompasses the constant density within the hydrophobic core of the bilayer, but also the tendency of chain segments to align. It is solved within self-consistent field theory. A model bilayer of DPPC undergoes a main-chain transition to a gel phase, while a bilayer of DOPC does not do so above zero degrees centigrade because of the double bond which disrupts order. We examine structural and thermodynamic properties of these membranes and find our results in reasonable accord with experiment. In particular, order-parameter profiles are in good agreement with NMR experiments. A phase diagram is obtained for mixtures of these lipids in a membrane at zero tension. The system undergoes phase separation below the main-chain transition temperature of the saturated lipid. Extensions to the ternary DPPC, DOPC, and cholesterol system are outlined.
Loopy Belief Propagation in the Presence of Determinism

It is well known that loopy Belief propagation (LBP) performs poorly on probabilistic graphical models (PGMs) with determinism. In this paper, we propose a new method for remedying this problem. The key idea in our method is finding a reparameterization of the graphical model such that LBP, when run on the reparameterization, is likely to have better convergence properties than LBP on the original graphical model. We propose several schemes for finding such reparameterizations, all of which leverage unique properties of zeros as well as research on LBP convergence done over the last decade. Our experimental evaluation on a variety of PGMs clearly demonstrates the promise of our method ‐ it often yields accuracy and convergence time improvements of an order of magnitude or more over LBP.
The health care debate in Canada: one Canadian radiologist's view.

Perception often is confused with fact. On each side of the CanadianeUS border Canadians and Americans traditionally have held that each other’s own style of health care provision is better than the other, just needing a few tweaks to get it perfect. Of late, the reality faced by both countries is that business as usual cannot be sustained, and that changes will be introduced either through research and discussion, or will be thrust upon us as the money runs out. There has been a noticeable upsurge in the interest of many US physicians in the Canadian model, fueled in part by the looming apprehension that the US system needs improvement. The alarming increase in the American debt as well as the other stressors on the health care system of which we are so well aware (aging population, expensive technologies, more informed and demanding population, inadequate care for the working poor, and so forth) warns of a brick wall up ahead. In addition, Michael Moore’s recent movie Sicko has shocked those who care about the system by showing half truths: that the American system is callous, inefficient, profit driven, and unfair, while other systems including those of Canada, Britain, and France are sanctuaries of compassion, accessibility, affordability, and serene satisfaction for its citizens. It is not within my knowledge or prerogative to comment on the limitations of the American health care system, except to acknowledge what we all knowdthat some of the finest medical institutions of higher learning and care in the world reside there. Nor am I in a position to speak with understanding of the systems in Great Britain or France. I have practiced radiology for 28 years in Canada in 4 provinces, and before that was trained in Canadian medical schools and residency programs. I have been a patient within the Canadian system, and have ongoing interactions with the system at this level for myself and my family. Our system is good, but far from perfect. To discuss the Canadian System, I
Drivers of national innovation in transition: Evidence from a panel of Eastern European countries

Abstract Innovation plays a crucial role in determining today’s economic growth patterns. But what enables some countries to innovate more than others? This study attempts to answer this question by analyzing in premiere a panel of sixteen Eastern European transition countries. It provides a detailed description of innovation identifying regional differences in terms of historical heritage, technological specialization, commitments and main actors involved in this process, before and after the fall of communism. Secondly, it explores empirically the main drivers of their innovative output, proxied by patents, using a variety of econometric techniques and control variables. The results confirm the crucial role of universities and existing national knowledge base complemented by R&D commitments from both public and private sources. Policy measures, such as intellectual property rights protection or a favorable business climate, increase significantly the propensity to patent, while measures of transitional downturn and industrial restructuring diminish it. Finally, globalization contributes to developing new innovations in these countries through inflows of foreign investment and trade.
NHC‐Cu‐Catalyzed Enantioselective Hydroboration of Acyclic and Exocyclic 1,1‐Disubstituted Aryl Alkenes

New chiral bidentate N-heterocyclic carbene—copper complexes (I) promote the enantioselective hydroboration of acyclic alkenes (II)/(V) and exocyclic 1,1-disubstituted alkenes (VII).
Foliations and Global Inversion

We consider topological conditions under which a locally invertible map admits a global inverse. Our main theorem states that a local diffeomorphism f : M → R is bijective if and only if Hn−1(M) = 0 and the pre-image of every affine hyperplane is non-empty and acyclic. The proof is based on some geometric constructions involving foliations and tools from intersection theory. This topological result generalizes in finite dimensions the classical analytic theorem of Hadamard-Plastock, including its recent improvement by Nollet-Xavier. The main theorem also relates to a conjecture of the aforementioned authors, involving the well known Jacobian Conjecture in algebraic geometry.
In situ measurements of the plasma bulk velocity near the Io flux tube

The flow around the Io flux tube was studied by analyzing the eleven spectra taken by the Voyager 1 Plasma Science (PLS) experiment in its vicinity. The bulk plasma parameters were determined using a procedure that uses the full response function of the instrument and the data in all four PLS sensors. The mass density of the plasma in the vicinity of Io is found to be 22,500 + or - 2,500 amu/cu cm and its electron density is found to be 1500 + or - 200/cu cm. The Alfven speed was determined using three independent methods; the values obtained are consistent and taken together yield V sub A = 300 + or - 50 km/sec, corresponding to an Alfven Mach number of 0.19 + or - 0.02. For the flow pattern, good agreement was found with the model of Neubauer (1980), and it was concluded that the plasma flows around the flux tube with a pattern similar to the flow of an incompressible fluid around a long cylinder obstacle of radius 1.26 + or - 0.1 R sub Io.
A generalized target-driven cache replacement policy for mobile environments

Caching frequently accessed data items on the client side is an effective technique to improve the system performance in wireless networks. Due to cache size limitations, cache replacement algorithms are used to find a suitable subset of items for eviction from the cache. Many existing cache replacement algorithms employ a value function of different factors such as time since last access, entry time of the item in the cache, transfer time, item expiration time and so on. However, most of the existing algorithms are designed for WWW environment under weak consistency model. Their choices of value functions are based on experience and on a value function which only works for a specific performance metric. In this paper, we propose a generalized value function for cache replacement algorithms for wireless networks under a strong consistency model. The distinctive feature of our value function is that it is generalized and can be used for various performance metrics by making the necessary changes. Further, we prove that the proposed value function can optimize the access cost in our system model. To demonstrate the practical effectiveness of the generalized value function, we derive two specific functions and evaluate them by setting up two different targets: minimizing the query delay and minimizing the downlink traffic. Compared to previous schemes, our algorithm significantly improves the performance in terms of query delay or in terms of bandwidth utilization depending on the specified target.
On the intrinsic Rent parameter and spectra-based partitioning methodologies

The complexity of circuit designs has necessitated a top-down approach to layout synthesis. A large body of work shows that a good layout hierarchy, or partitioning tree, as measured by the associated Rent parameter, will correspond to an area-efficient layout. We define the intrinsic Rent parameter of a netlist to be the minimum possible Rent parameter of any partitioning tree for the netlist. Experimental results show that spectra-based ratio cut partitioning algorithms yield partitioning trees with the lowest observed Rent parameter over all benchmarks and over all algorithms tested. For examples where the intrinsic Rent parameter is known, spectral ratio cut partitioning yields a partitioning tree with Rent parameter essentially identical to this theoretical optimum. These results have deep implications with respect to both the choice of partitioning algorithms for top-down layout, as well as new approaches to layout area estimation. The paper concludes with directions for future research, including several promising techniques for fast estimation of the (intrinsic) Rent parameter. >
The Kac Model Coupled to a Thermostat

In this paper we study a model of randomly colliding particles interacting with a thermal bath. Collisions between particles are modeled via the Kac master equation while the thermostat is seen as an infinite gas at thermal equilibrium at inverse temperature \(\beta \). The system admits the canonical distribution at inverse temperature \(\beta \) as the unique equilibrium state. We prove that any initial distribution approaches the equilibrium distribution exponentially fast both by computing the gap of the generator of the evolution, in a proper function space, as well as by proving exponential decay in relative entropy. We also show that the evolution propagates chaos and that the one particle marginal, in the large system limit, satisfies an effective Boltzmann-type equation.
Globalization of Financial Institutions: Evidence from Cross-Border Banking Performance

We address the causes, consequences, and implications of the cross-border consolidation of financial institutions by reviewing several hundred studies, providing comparative international data, and estimating cross-border banking efficiency in France, Germany, Spain, the U.K., and the U.S. during the 1990s. We find that, on average, domestic banks have higher profit efficiency than foreign banks. However, banks from at least one country (the U.S.) appear to operate with relatively high efficiency both at home and abroad. If these results continue to hold, they do not preclude successful international expansion by some financial firms, but they do suggest limits to global consolidation.
Optimal Descending Mechanisms for Constrained Procurement

Descending mechanisms for procurement (or, ascending mechanisms for selling) have been well-recognized for their simplicity from the viewpoint of bidders—they require less bidder sophistication as compared to sealed-bid mechanisms. In this study, we consider procurement under each of two types of constraints: (1) Individual/Group Capacities: limitations on the amounts that can be sourced from individual and/or subsets of suppliers, and (2) Business Rules: lower and upper bounds on the number of suppliers to source from, and on the amount that can be sourced from any single supplier. We analyze two procurement problems, one that incorporates individual/group capacities and another that incorporates business rules. In each problem, we consider a buyer who wants to procure a fixed quantity of a product from a set of suppliers, where each supplier is endowed with a privately known constant marginal cost. The buyer's objective is to minimize her total expected procurement cost. For both problems, we present descending auction mechanisms that are optimal mechanisms. We then show that these two problems belong to a larger class of mechanism design problems with constraints specified by polymatroids, for which we prove that optimal mechanisms can be implemented as descending mechanisms