cssi/SciSciGPT-SciSciNet huggingface dataset:
A scalable low-latency cache invalidation strategy for mobile environments

Caching frequently accessed data items on the client side is an effective technique for improving performance in a mobile environment. Classical cache invalidation strategies are not suitable for mobile environments due to frequent disconnections and mobility of the clients. One attractive cache invalidation technique is based on invalidation reports (IRs). However, the IR-based cache invalidation solution has two major drawbacks, which have not been addressed in previous research. First, there is a long query latency associated with this solution since a client cannot answer the query until the next IR interval. Second, when the server updates a hot data item, all clients have to query the server and get the data from the server separately, which wastes a large amount of bandwidth. In this paper, we propose an IR-based cache invalidation algorithm, which can significantly reduce the query latency and efficiently utilize the broadcast bandwidth. Detailed analytical analysis and simulation experiments are carried out to evaluate the proposed methodology. Compared to previous IR-based schemes, our scheme can significantly improve the throughput and reduce the query latency, the number of uplink request, and the broadcast bandwidth requirements.
An apparatus to control and monitor the para-D2 concentration in a solid deuterium, superthermal source of ultra-cold neutrons

Abstract Controlling and measuring the concentration of para-D 2 is an essential step toward realizing solid deuterium as an intense ultra-cold neutron source. To this end, we implemented an experimental technique to convert para- to ortho-deuterium molecules by flowing D 2 gas through a cryogenic cell filled with paramagnetic hydrous ferric oxide granules. This process efficiently reduced the para-D 2 concentration from 33.3% to 1.5%. Rotational Raman spectroscopy was applied to measure the residual para-D 2 contamination to better than 2 parts in 10 3 , and the hydrogen contamination to 1 part in 10 3 . We also contrast our optical technique to conventional thermal conductivity measurements of the para-D 2 concentration, reporting some of the relevant strengths and weaknesses of our implementation of each technique.
Generalized Discrete Fourier Transform With Nonlinear Phase

Constant modulus transforms like discrete Fourier transform (DFT), Walsh transform, and Gold codes have been successfully used over several decades in several engineering applications, including discrete multi-tone (DMT), orthogonal frequency division multiplexing (OFDM) and code division multiple access (CDMA) communications systems. In this paper, we present a generalized framework for DFT called Generalized DFT (GDFT) with nonlinear phase by exploiting the phase space. We show that GDFT offers sizable correlation improvements over DFT, Walsh, Oppermann and Gold codes, leading to better performance in all multi-carrier communications scenarios investigated. We also highlight how known constant modulus orthogonal transforms are special solutions of the proposed GDFT framework. Moreover, we introduce practical design methods offering computationally efficient implementations of GDFT as enhancements to DFT. We conclude the paper with examples of communications applications where GDFT is shown to outperform DFT and other known constant modulus bases.
Preparation and reactions of 1,1-zinc, boron and 1,1-copper, boron alkenyl bimetallics

Abstract Pinacol α-iodoalkenylboronates 8 , readily prepared by the hydroboration of 1-iodoalkynes, were converted to 1,1-bimetallics of boron and zinc or copper which react with a wide range of electrophiles affording polyfunctional boronic esters. After H 2 O 2 oxidation (30% H 2 O 2 , sat.aq. NaOAc), polyfunctional ketones were produced in good to excellent yields.
Baroclinic Motions and Energetics as Measured by Altimeters

Small surface displacements appearing in tide gauge and altimetric records are used to detect hydrostatic baroclinic modes in the ocean. Those deflections are a small fraction of the interior isopycnal vertical displacements and are dependent directly upon the in situ stratification. Conversion of surface height to interior amplitudes and energies encounters significant spatial and seasonal shifts that need to be accounted for in quantitative use. This technical article analyzes the global-scale spatial variations in the relationship between surface deflections and interior motions. Similar considerations make it possible to use altimetric data to estimate the deep interior temperature variability as a function of position, calculations having a strong influence on abyssal trend determination in the presence of eddies.
Tone Discrimination as a Window Into Acoustic Perceptual Deficits in Parkinson’s Disease

Purpose Deficits in auditory perception compromise a range of linguistic processes in persons with Parkinson’s disease (PD), including speech perception and sensitivity to affective and linguistic ...
The electrical state of the Sun

The magnetic field due to the rotation of our galaxy is calculated, and it is shown (a) that electricity cannot be annihilated in the sun or stars; (b) that the net electrical charge on the sun or a typical star cannot exceed 1 coulomb. The electric fields, space-charge, and potentials of the solar atmosphere are calculated from data relating to the solar anomalous rotation and numerical values given. The negative surface charge on the sun is calculated to be of the order of 109 e.m.u. The problem of the maintenance of the solar electric field is touched upon. (The paper is published in full in Phys. Rev., v. 37, 983–989, April 15, 1931.)
Resource Allocation in the Brain

When an individual performs several tasks simultaneously, processing resources must be allocated to dierent brain systems to produce energy for neurons to re. Following the evidence from neuroscience, we model the brain as an organization in which a coordinator allocates limited resources to the brain systems responsible for the dierent tasks. Systems are privately informed about the amount of resources necessary to perform their task and compete to obtain the resources. The coordinator arbitrates the demands while satisfying the resource constraint. We show that the optimal mechanism is to impose to each system with privately known needs a cap in resources that depends negatively on the amount of resources requested by the other system. This allocation can be implemented using a biologically plausible mechanism. Finally, we provide some implications of our theory: (i) performance can be awless for suciently simple tasks, (ii) the dynamic allocation rule exhibits inertia (current allocations are increasing in past needs), and (iii) dierent cognitive tasks are performed by dierent systems only if the tasks are suciently important.
2',2'-Ligation Demonstrates the Thermal Dependence of DNA-Directed Positional Control.

Abstract An oligodeoxynucleotide (ODN) containing a 2′-aminoalkylmercaptouridine was ligated chemically with another ODN containing a 2′-carboxyalkylmercaptouridine to produce a 2′,2′-amide linked conjugate. Templation by a DNA hairpin resulted in ligation yields of >95%. At room temperature, similar yields were obtained for amide ligations between pendent nucleotides located adjacent to each other or separated by three nucleotides. However, at 4 °C, ligation was vastly favored for the case where the pendent amine and carboxylate were attached to adjacent residues (i.e., at the 3′- and 5′-terminus of the two ODNs). No reaction was observed to occur either at 4 °C or at room temperature between pendent nucleotides separated by nine nucleotides. Denaturing gel electrophoresis, MALDI-TOF MS, and full nuclease digestion coupled with LC–MS were used to characterize the reaction products.
Wear reduction through piezoelectrically-assisted ultrasonic lubrication

Traditional lubricants are undesirable in harsh aerospace environments and certain automotive applications. Ultrasonic vibrations can be used to reduce and modulate the effective friction coefficient between two sliding surfaces. This paper investigates the relationship between friction force reduction and wear reduction in ultrasonically lubricated surfaces. A pin-on-disc tribometer is modified through the addition of a piezoelectric transducer which vibrates the pin at 22 kHz in the direction perpendicular to the rotating disc surface. Friction and wear metrics including volume loss, surface roughness, friction forces and apparent stick-slip effects are measured without and with ultrasonic vibrations at three different sliding velocities. SEM imaging and 3D profilometry are used to characterize the wear surfaces and guide model development. Over the range of speeds considered, ultrasonic vibrations reduce the effective friction force up to 62% along with a wear reduction of up to 49%. A simple cube model previously developed to quantify friction force reduction is implemented which describes wear reduction within 15% of the experimental data.
Impact of low k dielectrics on electromigration reliability for Cu interconnects

Multi-link statistical test structures were used to study the effect of low k dielectrics on EM reliability of Cu interconnects. Experiments were performed on dual-damascen e Cu interconnects integrated with oxide, CVD low k, porous MSQ, and organic polymer ILD. The EM activation energy for Cu structures was found to be between 0.8 and 1.0 eV, indicating mass transport is dominated by diffusion at the Cu/SiNx cap-layer interface, independent of ILD. Compared with oxide, the decrease in lifetime and (jL)c observed for low-k structures can be attributed to less dielectric confinement in the low k structures. An effective modulus B obtained by finite element analysis was used to account for the dielectric confinement effect on EM. For all the ILDs studied, (jL)c showed no temperature dependence.
CHARACTERIZATION AND PROPERTIES OF SOME DIALKYL-1-(N,N-DIALKYLAMINO)-ALKYLPHOSPHONATES AND THEIR HYDROCHLORIDE SALTS

Abstract Several new dialkyl-1-(N,N- dialkylamino)alkylphosphonates were synthesized1a as well as their hydrochloride salts. These compounds, along with two previously reported compounds, have been characterized by spectroscopic methods as well as elemental analysis. Spectral analysis indicates that the molecules assume an oriented posture in solution which can influence their reactivity. Additionally, the hydrochloride salts of the diethyl-1-(N,N-dimethylamino)alkylphosphonates have shown anti-viral activity.
An addition—cyclization—elimination mechanism for dehydro Diels-Alder reactions

Abstract Vinylacetylene 1 undergoes reactions with dienophiles by a mechanism involving initial addition of acids to the triple bond, cycloaddition, and elimination of acid.
Two Factors Along the Yield Curve

Are all two-factor term structure models the same? We specify three models and estimate each on different parts of the U.S. yield curve. The exercise provides insights on reconciling the term structure's time series with its cross-section and on relating it to fundamentals. Our evidence favours models where one factor reverts to a time-varying mean. One such model explains shorter-term yields and another longer-term yields. The models differ primarily because mean reversion is much faster near the yield curve's short end than near its long end. The factors seem to capture mean reversion in inflation and the Fed's target rate.
Parameter estimation for coupled multivariable error models

An adaptive algorithm is developed for estimating the parameters of a linear multivariable error model with coupled dynamics, using estimation errors for coupling inputs. Coupled dynamics in an error equation lead to a new type of error models which have different regressors but the same parameter error. A total cost function is used to derive a desired adaptive law for updating the parameter estimates. As an application, this algorithm is employed for control and identification of multivariable systems with actuator uncertainties.
Challenges in the Deployment of Visuo-Haptic Virtual Environments on the Internet

Haptic sensory feedback has been shown to complement the visual and auditory senses, improve user performance and provide a greater sense of togetherness in collaborative and interactive virtual environments. However, we are faced with numerous challenges when deploying these systems over the present day Internet. The most significant of these challenges are the network performance limitations of the Wide Area Networks. In this paper, we offer a structured examination of the current challenges in the deployment of haptic-based distributed systems by analyzing the recent advances in the understanding of these challenges and the progress that has been made to overcome them.
Motivations, Obstacles, and Resources: The Adoption Of The General-Purpose Local Option Sales Tax in Georgia Counties

Local governments in Georgia have been authorized since the 1970s to levy a 1 percent general-purpose Local Option Sales Tax (LOST), which is earmarked for property tax relief. Using data during 1975 to 2002, this study examines the adoption of the LOST through a discrete-time event history analysis. The dependent variable is the probability that an eligible county will adopt it in a particular year. This probability is negatively related to the obstacles prohibiting the innovation and positively related to (1) the motivations to innovate and (2) the resources for overcoming the obstacles. The findings suggest that the motivations are higher in counties with higher property tax millage rates and the potential of sales tax exportation; the obstacles include high existing sales tax rates and severe tax competition; and the major resource for overcoming these obstacles is the adoption of the LOST in other Georgia counties.
A practical ontology for the large-scale modeling of scholarly artifacts and their usage

The large-scale analysis of scholarly artifact usage is constrained primarily by current practices in usage data archiving, privacy issues concerned with the dissemination of usage data, and the lack of a practical ontology for modeling the usage domain. As a remedy to the third constraint, this article presents a scholarly ontology that was engineered to represent those classes for which large-scale bibliographic and usage data exists, supports usage research, and whose instantiation is scalable to the order of 50 million articles along with their associated artifacts (e.g. authors and journals) and an accompanying 1 billion usage events. The real world instantiation of the presented abstract ontology is a semantic network model of the scholarly community which lends the scholarly process to statistical analysis and computational support. We present the ontology, discuss its instantiation, and provide some example inference rules for calculating various scholarly artifact metrics.
Properties of the composite quadratic Lyapunov functions

A composite quadratic Lyapunov function introduced recently was shown to be very useful in the study of set invariance properties for linear systems with input and state constraints and for systems with a class of convex/concave nonlinearities. In this note, more properties about this function are revealed. In particular, we study the continuity of the optimal parameter involved in this function. This continuity is crucial in the construction of a continuous feedback law which makes the convex hull of a group of ellipsoids invariant.
Convenient syntheses of 2,3,4,5-tetrahydro-1,4-benzothiazepines, -1,4-benzoxazepines and -1,4-benzodiazepines

4-Benzotriazolylmethyl-2,3,4,5-tetrahydro-1,4-benzothiazepines 5a,b, -1,4-benzoxazepine (12) and -1,4-benzodiazepine (20) are obtained via aluminium chloride mediated intramolecular cyclizations of N,N-bis(1H-1,2,3-benzotriazol-1-ylmethyl)-2-(arylthio)ethan-1-amines 4a,b, -2-(phenoxy)ethan-1-amine (11) and -N-[2-(N′-methylanilino)ethyl]amine (19), respectively. Subsequent nucleophilic substitutions of the benzotriazolyl group in 5a,b, 12 and 20 succeeded with Grignard reagents, triethyl phosphite, sodium borohydride, and a silyl enol ether to give novel 2,3,4,5-tetrahydro-1,4-benzothiazepines 6–9, -1,4-benzoxazepines 13 and 14, and -1,4-benzodiazepines 21–23 in good yields.
Starting from Scratch Building Community Support for Labor Organizing in Indianapolis

This study compares how two union organizing campaigns have attempted to mobilize community support by examining the opportunity structure for organizing in Indianapolis, comparing the community ou...
Optimal estimation with limited measurements

This paper introduces a sequential estimation problem with two decision makers, or agents, who work as members of a team. One of the agents sits at an observation post, and makes sequential observations about the state of an underlying stochastic process for a fixed period of time. The observer agent upon observing the process makes a decision as to whether or not to disclose some information about the process to the other agent who acts as an estimator. The estimator agent sequentially estimates the state of the process. The agents have the common objective of minimising a performance criterion with the constraint that the observer agent may only act a limited number of times.
Drawing planar graphs with circular arcs

In this paper we address the problem of drawing planar graphs with circular arcs while maintaining good angular resolution and small drawing area. We present a lower bound on the area of drawings in which edges are drawn using exactly one circular arc. We also give an algorithm for drawing n-vertex planar graphs such that the edges are sequences of two continuous circular arcs. The algorithm runs in O(n) time and embeds the graph on the O(n) × O(n) grid, while maintaining ?(1/d(v)) angular resolution, where d(v) is the degree of vertex v. Since in this case we use circular arcs of infinite radius, this is also the first algorithm that simultaneously achieves good angular resolution, small area, and at most one bend per edge using straight-line segments. Finally, we show how to create drawings in which edges are smooth C1-continuous curves, represented by a sequence of at most three circular arcs.
Algorithmically Random Functions and Effective Capacities

We continue the investigation of algorithmically random functions and closed sets, and in particular the connection with the notion of capacity. We study notions of random continuous functions given in terms of a family of computable measures called symmetric Bernoulli measures. We isolate one particular class of random functions that we refer to as random online functions \(F\), where the value of \(y(n)\) for \(y = F(x)\) may be computed from the values of \(x(0),\dots ,x(n)\). We show that random online functions are neither onto nor one-to-one. We give a necessary condition on the members of the ranges of random online functions in terms of initial segment complexity and the associated computable capacity. Lastly, we introduce the notion of Martin-Lof random online partial function on \(2^\omega \) and give a family of online partial random functions the ranges of which are precisely the random closed sets introduced in [2].
Advances towards a general-purpose societal-scale human-collective problem-solving engine

Human collective intelligence has proved itself as an important factor in a society's ability to accomplish large-scale behavioral feats. As societies have grown in population-size, individuals have seen a decrease in their ability to actively participate in the problem-solving processes of the group. Representative decision-making structures have been used as a modern solution to society's inadequate information-processing infrastructure. With computer and network technologies being further embedded, within the fabric of society, the implementation of a general-purpose societal-scale human-collective problem-solving engine is envisioned as a means of furthering the collective-intelligence potential of society. This paper provides both a novel framework for creating collective intelligence systems and a method for implementing a representative and expertise system based on social-network theory
Decadal-scale sensitivity of Northeast Greenland ice flow to errors in surface mass balance using ISSM

The behavior of the Greenland Ice Sheet, which is considered a major contributor to sea level changes, is best understood on century and longer time scales. However, on decadal time scales, its response is less predictable due to the difficulty of modeling surface climate, as well as incomplete understanding of the dynamic processes responsible for ice flow. Therefore, it is imperative to understand how modeling advancements, such as increased spatial resolution or more comprehensive ice flow equations, might improve projections of ice sheet response to climatic trends. Here we examine how a finely resolved climate forcing influences a high-resolution ice stream model that considers longitudinal stresses. We simulate ice flow using a two-dimensional Shelfy-Stream Approximation implemented within the Ice Sheet System Model (ISSM) and use uncertainty quantification tools embedded within the model to calculate the sensitivity of ice flow within the Northeast Greenland Ice Stream to errors in surface mass balance (SMB) forcing. Our results suggest that the model tends to smooth ice velocities even when forced with extreme errors in SMB. Indeed, errors propagate linearly through the model, resulting in discharge uncertainty of 16% or 1.9 Gt/yr. We find that mass flux is most sensitive to local errors but is also affected by errors hundreds of kilometers away; thus, an accurate SMB map of the entire basin is critical for realistic simulation. Furthermore, sensitivity analyses indicate that SMB forcing needs to be provided at a resolution of at least 40 km.
Spin dynamics and transport in gapped one-dimensional Heisenberg antiferromagnets at nonzero temperatures

We discuss the theory of the nonzero temperature $(T)$ spin dynamics and transport in one-dimensional Heisenberg antiferromagnets with a gap $\ensuremath{\Delta}$. For $T\ensuremath{\ll}\ensuremath{\Delta}$, we develop a semiclassical picture of thermally excited particles. Multiple inelastic collisions between the particles are crucial, and are described by a two-particle $\mathcal{S}$ matrix which is shown to have a superuniversal form at low momenta. This is established by computations on the $O(3)$ $\ensuremath{\sigma}$ model, and strong- and weak-coupling expansions (the latter using a Majorana fermion representation) for the two-leg $S=1/2$ Heisenberg antiferromagnetic ladder. As an aside, we note that the strong-coupling calculation reveals an $S=1$, two-particle bound state which leads to the presence of a second peak in the $T=0$ inelastic neutron-scattering (INS) cross section for a range of values of momentum transfer. We obtain exact, or numerically exact, universal expressions for the thermal broadening of the quasiparticle peak in the INS cross section, the spin diffusivity, and for the field dependence of the NMR relaxation rate ${1/T}_{1}$ of the effective semiclassical model; these are expected to be asymptotically exact for the quantum antiferromagnets in the limit $T\ensuremath{\ll}\ensuremath{\Delta}$. The results for ${1/T}_{1}$ are compared with the experimental findings of Takigawa et al. [Phys. Rev. Lett. 76, 2173 (1996)] and the agreement is quite good. In the regime $\ensuremath{\Delta}lTl$(a typical microscopic exchange) and we argue that a complementary description in terms of semiclassical waves applies, and give some exact results for the thermodynamics and dynamics.
The colored Eulerian descent algebra

Using a new colored analogue of $$P$$P-partitions, we prove the existence of a colored Eulerian descent algebra which is a subalgebra of the Mantaci---Reutenauer algebra. This algebra has a basis consisting of formal sums of colored permutations with the same number of descents (using Steingrimsson's definition of the descent set of a colored permutation). The colored Eulerian descent algebra extends familiar Eulerian descent algebras from the symmetric group algebra and the hyperoctahedral group algebra to colored permutation group algebras. We also describe orthogonal idempotents that span the colored Eulerian descent algebra and include, as a special case, the familiar Eulerian idempotents in the group algebra of the symmetric group.
Probabilistic databases with MarkoViews

Most of the work on query evaluation in probabilistic databases has focused on the simple tuple-independent data model, where tuples are independent random events. Several efficient query evaluation techniques exists in this setting, such as safe plans, algorithms based on OBDDs, tree-decomposition and a variety of approximation algorithms. However, complex data analytics tasks often require complex correlations, and query evaluation then is significantly more expensive, or more restrictive.In this paper, we propose MVDB as a framework both for representing complex correlations and for efficient query evaluation. An MVDB specifies correlations by views, called MarkoViews, on the probabilistic relations and declaring the weights of the view's outputs. An MVDB is a (very large) Markov Logic Network. We make two sets of contributions. First, we show that query evaluation on an MVDB is equivalent to evaluating a Union of Conjunctive Query(UCQ) over a tuple-independent database. The translation is exact (thus allowing the techniques developed for tuple independent databases to be carried over to MVDB), yet it is novel and quite non-obvious (some resulting probabilities may be negative!).This translation in itself though may not lead to much gain since the translated query gets complicated as we try to capture more correlations. Our second contribution is to propose a new query evaluation strategy that exploits offline compilation to speed up online query evaluation. Here we utilize and extend our prior work on compilation of UCQ. We validate experimentally our techniques on a large probabilistic database with MarkoViews inferred from the DBLP data.
Instantaneous Two-Dimensional Gas Concentration Measurements by Light Scattering

A light-scatteri ng technique which makes it possible to map out the instantaneous concentration field at 104 points in a thin sheet intersecting a nonreacting turbulent flow is described. The concentration is inferred from the intensity of the Lorenz/Mie scattered radiation from a seeded flow. The signal is detected by a computer- controlled, low-light-level TV camera and the resulting data have the advantage of being both quantitative and visually interpretable. The technique can be modified to obtain temporal as well as spatial information. In addition, the use of other scattering mechanisms for similar measurements is discussed. ITH the realization of the importance of coherent structures in turbulent flows, there has been an increased interest in experimental means of obtaining in- formation on the nature of these structures. The use of multipoint probes, conditional sampling techniques, and flow visualization has provided much new data. The picture is still incomplete, however, since most simultaneous multipoint measurements have been limited to a relatively small number of points, usually along a single line. Also, flow visualization, which provides a large amount of information, is generally only qualitative. In order to provide a large number of simultaneous, quantitative measurements, a nonintrusive light-scattering technique has been developed which makes it possible to measure gas concentration at 10,000 points within a plane intersecting a nonreacting turbulent flow. The technique used is an extension of one first developed by Rosensweig1 and later employed by several other researchers. A thorough review of the method has been given by Becker.2 The technique is based on the fact that, if a gas is seeded with light-scattering particles having dimensions so small that there is negligible "slip" between trie particles and the surrounding gas, each unit mass of the seeded gas will be marked by ap- proximately the same number of aerosols in the course of its motion. (The size of the particles is sufficiently large so that there is negligible Brownian diffusion of particles due to molecular agitation. A precise estimate of how well the particles follow the fluid motion is given later.) If the seeded gas mixes with a second unseeded gas, the number of scat- tering particles in each unit volume of the mixture will be reduced and the scattered radiation will be proportionall y less. Early experiments of this type used a bright lamp to illuminate a smoke-laden flow. Later, Shaughnessy and Morton3 found that using a laser as the illumination source improved the signal/noise ratio. By a system of lenses and slits, the scattering from a small volume of seeded gas was collected and focused onto a photomultiplie r tube (PMT). The PMT output was then shown to be proportional to the seeded gas concentration, and it was possible to measure average concentration, concentration fluctuations, and power spectra at a single point. Our experiments invoke the same principle but, rather than measuring the time evolution of the
Interpreting the Cosmic Infrared Background: Constraints on the Evolution of the Dust-enshrouded Star Formation Rate

The mid-infrared local luminosity function is evolved with redshift to —t the spectrum of the cosmic infrared background (CIRB) at j[ 5 km and the galaxy counts from various surveys at mid-infrared, far-infrared, and submillimeter wavelengths. A variety of evolutionary models provide satisfactory —ts to the CIRB and the number counts. The degeneracy in the range of models cannot be broken by current observations. However, the diUerent evolutionary models yield approximately the same comoving number density of infrared luminous galaxies as a function of redshift. Since the spectrum of the cosmic background at j[ 200 km is quite sensitive to the evolution at high redshift, i.e., z [ 1, all models that —t the counts require a —attening at z D 0.8 to avoid overproducing the CIRB. About 80% of the 140 km CIRB is produced at 0 \ z \ 1.5, while only about 30% of the 850 km background is produced within the same redshift range. The nature of the evolution is then translated into a measure of the dustenshrouded star formation rate (SFR) density as a function of redshift and compared with estimates from rest-frame optical/ultraviolet surveys. The dust-enshrouded SFR density appears to peak at z \ 0.8 ^ 0.1, much sooner than previously thought, with a value of yr~1 Mpc~3, and remains almost 0.25 ~0.10.12 M _ constant up to z D 2. At least 70% of this star formation takes place in infrared luminous galaxies with The long-wavelength observations that constrain our evolutionary models do not strongL IR [ 1011 L _ . ly trace the evolution at z [ 2 and a drop-oU in the dust-enshrouded SFR density is consistent with both the CIRB spectrum and the number counts. However, a comparison with the infrared luminosity function derived from extinction-corrected rest-frame optical/ultraviolet observations of the Lyman break galaxy population at z D 3 suggests that the almost —at comoving SFR density seen between redshifts of 0.8 and 2 extends up to a redshift of z D 4. (%)
Closed-Loop Input Shaping for Flexible Structures Using Time-Delay Control

Input shaping techniques reduce the residual vibration in flexible structures by convolving the command input with a sequence of impulses. The exact cancellation of the residual structural vibration via input shaping is dependent on the amplitudes and instances of impulse application. A majority of the current input shaping schemes are inherently open-loop where impulse application at inaccurate instances can lead to system performance degradation. In this paper, we develop a closed-loop control design framework for input shaped systems. This framework is based on the realization that the dynamics of input shaped systems give rise to time delays in the input. Thus, we exploit the feedback control theory of time delay systems for the closed-loop control of input shaped flexible structures. A Riccati equation-based and a linear matrix inequality-based frameworks are developed for the stabilization of systems with uncertain, multiple input delays. Next, the aforementioned framework is applied to two input shaped flexible structure systems. This framework guarantees closed-loop system stability and performance when the impulse train is applied at inaccurate instances. Two illustrative numerical examples demonstrate the efficacy of the proposed closed-loop input shaping controller.
Design of a VHF-band RF photoinjector with megahertz beam repetition rate

New generation accelerator-based X-ray light sources require high quality beams with high average brightness. Normal conducting L- and S-band photo injectors are limited in repetition rate and D-C (photo)injectors are limited in field strength at the cathode. We propose a low frequency normal-conducting cavity, operating at 50 to 100 MHz CW, to provide beam bunches of up to the cavity frequency. The photoinjector uses a re-entrant cavity structure, requiring less than 100 kW CW, with a peak wall power density less than 10 W/cm2. The cavity will support a vacuum down to 10 picoTorr, with a load-lock mechanism for easy replacement of photocathodes. The photocathode can be embedded in a magnetic field to provide correlations useful for emittance exchange. Beam dynamics simulations indicate that normalized emittances smaller than 1 mm-mrad are possible with gap voltage of 750 kV, with fields up to 20 MV/m at the photocathode, for 1 nanocoulomb charge per bunch after acceleration and emittance compensation. Long-bunch operation (10's of picosecond) is made possible by the low cavity frequency, permitting low bunch current at the 750 kV gap voltage.
Earnings Estimates, Predictor Specification, and Measurement Error

Increased use of expectational data for modeling stock returns places a spotlight on the specification of predictor variables. Choices between alternative specifications of a given predictor such as E/P or earnings trend, for example, can have wide-ranging effects on portfolio selection and quantitative modeling. Investigation here indicates that the importance of predictor specification may vary depending upon the predictor and the investment strategy, and that the relationship between predictors and returns may vary across types of stocks.
The Reciprocity Law for Dedekind Sums via the Constant Ehrhart Coefficient

These sums appear in various branches of mathematics: number theory, algebraic geometry, and topology; they have consequently been studied extensively in various contexts. These include the quadratic reciprocity law [13], random number generators [12], group actions on complex manifolds [9], and lattice point problems ([14] or [5]). Dedekind was the first to show the following reciprocity law [3]:
A metal–organic framework material that functions as an enantioselective catalyst for olefin epoxidation

A new microporous metal–organic framework compound featuring chiral (salen)Mn struts is highly effective as an asymmetric catalyst for olefin epoxidation, yielding enantiomeric excesses that rival those of the free molecular analogue. Framework confinement of the manganese salen entity enhances catalyst stability, imparts substrate size selectivity, and permits catalyst separation and reuse.
Country Size, International Trade, and Aggregate Fluctuations in Granular Economies

This paper proposes a new mechanism by which country size and international trade affect macroeconomic volatility. We study a model with heterogeneous firms that are subject to idiosyncratic firm-specific shocks, calibrated to data for the 50 largest economies in the world. When the firm size distribution follows a power law with an exponent close to minus one, idiosyncratic shocks to large firms have an impact on aggregate volatility. Smaller countries have fewer firms and, thus, higher volatility. Trade opening makes the large firms more important, thus raising macroeconomic volatility. Trade can increase aggregate volatility by 15–20 percent in some small open economies.
Simulation-Based Distributions of Earthquake Recurrence Times on the San Andreas Fault System

Earthquakes on a specified fault (or fault segment) with magnitudes greater than a specified value have a statistical distribution of recurrence times. The mean recurrence time can be related to the rate of strain accumulation and the strength of the fault. Very few faults have a recorded history of earthquakes that define a distribution well. For hazard assessment, in general, a statistical distribution of recurrence times is assumed along with parameter values. Assumed distributions include the Weibull (stretched exponential) distribution, the lognormal distribution, and the Brownian passage-time (inverse Gaussian) distribution. The distribution of earthquake waiting times is the conditional probability that an earthquake will occur at a time in the future if it has not occurred for a specified time in the past. The distribution of waiting times is very sensitive to the distribution of recurrence times. An exponential distribution of recurrence times is Poissonian, so there is no memory of the last event. The distribution of recurrence times must be thinner than the exponential if the mean waiting time is to decrease as the time since the last earthquake increases. Neither the lognormal or the Brownian passage time distribution satisfies this requirement. We use the “Virtual California” model for earthquake occurrence on the San Andreas fault system to produce a synthetic distribution of earthquake recurrence times on various faults in the San Andreas system. We find that the synthetic data are well represented by Weibull distributions. We also show that the Weibull distribution follows from both damage mechanics and statistical physics.
The role of flow in green chemistry and engineering

Flow chemistry and continuous processing can offer many ways to make synthesis a more sustainable practice. These technologies help bridge the large gap between academic and industrial settings by often providing a more reproducible, scalable, safe and efficient option for performing chemical reactions. In this review, we use selected examples to demonstrate how continuous methods of synthesis can be greener than batch synthesis on a small and a large scale.
Interception of comets and asteroids on collision course with Earth

I derive expressions for the weight and range of applicability of interceptors capable of deflecting a comet or asteroid on collision course with Earth. The expressions use a fairly general relationship between the energy deposited and the mass of material blown off the astral assailant. To assess the probability that the astral assailant will fracture, I also calculate the fraction of the astral assailant's mass that will be blown off. The interaction is calculated for both kinetic-energy deflection and nuclear-explosive deflection. In the nuclear-explosive case, I calculate the interceptor mass and cratering effect for detonations above the surface and below the surface as well as directly on the surface of the astral assailant. Because the wide range of densities and material properties that the astral assailant may possess, the principal value of this work is to show the relationships among the salient parameters of the problem.
Capital versus Performance Covenants in Debt Contracts

We study the contracting role of financial covenants classified into two types. We argue that capital covenants control agency problems by maintaining sufficient equity capital and hence aligning debtholder-shareholder incentives, whereas performance covenants serve as tripwires that facilitate early transfers of control and renegotiations when performance deteriorates. We find that capital and performance covenants are negatively correlated but are not used interchangeably. Performance covenants are strong predictors of future contract renegotiations, while this is not the case for capital covenants. Further, restrictions on certain managerial actions are less common in conjunction with capital covenants, in line with their incentives alignment effect. We also study how the contracting value of accounting information affects covenant package design. We predict and find that performance covenants are contracted on when accounting information is descriptive of credit quality, while the opposite holds for capital covenants. This relation implies that properties of accounting information have a sizable effect on the design of financial contracts.
If It's Useful and You Know It, Do You Eat? Preschoolers Refrain from Instrumental Food

Marketers, educators, and caregivers often refer to instrumental benefits to convince preschoolers to eat (e.g., “This food will make you strong”). We propose that preschoolers infer that if food is instrumental to achieve a goal, it is less tasty, and therefore they consume less of it. Accordingly, we find that preschoolers (3–5.5 years old) rated crackers as less tasty and consumed fewer of them when the crackers were presented as instrumental to achieving a health goal (studies 1–2). In addition, preschoolers consumed fewer carrots and crackers when these were presented as instrumental to knowing how to read (study 3) and to count (studies 4–5). This research supports an inference account for the negative impact of certain persuasive messages on consumption: preschoolers who are exposed to one association (e.g., between eating carrots and intellectual performance) infer another association (e.g., between carrots and taste) must be weaker.
Some issues in gauge mediation

Abstract After briefly reviewing some arguments in favor of high scale and low scale supersymmetry breaking, I discuss a possible solution of the μ-problem of gauge mediated models.
Native–Exotic Species Richness Relationships Across Spatial Scales in a Prairie Restoration Matrix

In highly invaded ecosystems, restoration of native plant communities is dependent upon reducing exotic species relative to native species. Even so, in monitoring, the native–exotic species richness ratio has been shown to be scale-dependent. Measurement at small spatial scales (<1 m2) can reveal a negative native–exotic richness relationship, where niche occupation may prevent invasion. Conversely, at larger scales, a positive correlation may exist, where environmental heterogeneity and equally favorable conditions may drive native–exotic relationships. Here, we compare slopes of native–exotic relationships across spatial scales in a prairie undergoing active restoration. The observed native–exotic richness ratios varied considerably over scales ranging from 1 to 1,000 m2, emphasizing the importance of choosing a measurement scale that is most pertinent to the treatment and ecological mechanism used to evaluate restoration success. Our native–exotic richness slopes were positive over all scales, but lower than would be expected in a random community assembly, suggesting the influence of niche-based competition. Correspondingly, our native–exotic cover slope was more negative than a null model; however, areas of frequent fire treatments showed a significant deviation from null only for richness, indicating that burning may enhance native–exotic competitive dynamics for number of species but not cover. The negative native–exotic cover relationships appear to be driven in this system mainly by exotic graminoids, across burn treatments and native functional groups, supporting the concept that frequent burning can alter the dominant competitive mechanism from coverage of these exotic grasses to an improved environment for germination and dispersal of more native species.
Emergency Preparedness and Public Health: The Lessons of Hurricane Sandy

When Hurricane Sandy hit downtown Manhattan, three neighboring hospitals each made different decisions about when to evacuate. Across the metro region, more than five hospitals and over 20 nursing and assisted living facilities were evacuated, making this the central public health challenge of this calamitous event. It is a familiar story — a super storm comes ashore, infrastructure is overwhelmed, and healthcare facilities evacuate patients, with major delays in returning to normal functioning. Afterwards, policy makers evaluate lessons learned for the next disaster, but similar missteps are often repeated.Although not identical, it is instructive to compare Hurricane Katrina with the still unfolding events of Sandy. Unlike in Katrina, New York hospitals had more detailed emergency plans. What seemed to be missing, however, were clear and consistent criteria to guide evacuation decisions. Evacuation decisions are complex — a decision to evacuate prematurely places patients at risk, while waiting too long can have devastating consequences. Public officials, in collaboration with facilities, should decide whether to shelter in place or risk transfer of fragile patients. Governors should consider early emergency declarations, including request for a formal “public health emergency declaration”, to reduce legal concerns and regulatory constraints. Federal, state, and municipal authorities can better prepare for the next disaster and have a duty to do so.
Discovery of an M9.5 Candidate Brown Dwarf in the TW Hydrae Association: DENIS J124514.1–442907*

We report the discovery of a fifth candidate substellar system in the ~5-10 Myr TW Hydrae association: DENIS J124514.1-442907. This object has a NIR spectrum remarkably similar to that of 2MASS J1139511-315921, a known TW Hydrae brown dwarf, with low surface gravity features such as a triangular-shaped H band, deep H_2O absorption, weak alkali lines, and weak hydride bands. We find an optical spectral type of M9.5 and estimate a mass of ≾24 M_(Jup), assuming an age of ~5-10 Myr. While the measured proper motion for DENIS J124514.1-442907 is inconclusive as a test for membership, its position in the sky is coincident with the TW Hydrae association. A more accurate proper-motion measurement, higher resolution spectroscopy for radial velocity, and a parallax measurement are needed to derive the true space motion and to confirm its membership.