cssi/SciSciGPT-SciSciNet huggingface dataset:
Is there a connection between no-hair behavior and universality in gravitational collapse?

Abstract We apply linear perturbation theory to the study of the universality and criticality first observed by Choptuik in gravitational collapse. Since these are essentially nonlinear phenomena our approach provides a rough approximation. In spite of this, universal behavior of the final black hole mass is observed with an exponent only slightly higher than the observed value of 0.367. The universal behavior is based on the unique form that in-falling perturbations on black holes have at the horizon.
Integrated synthesis of assembly and fixture scheme for properly constrained assembly

This paper presents an integrated approach to design an assembly, fixture schemes, and an assembly sequence, such that the dimensional integrity of the assembly is insensitive to the dimensional variations of individual parts. The adjustability of critical dimensions and the proper constraining of parts during assembly process are the keys in achieving the dimensional integrity of the final assembly. A top-down design method is developed which recursively decomposes a lump of initial product geometry and fixture elements matching critical dimensions into parts and fixtures. At each recursion, joints are assigned to the interfaces between two subassemblies to ensure that parts and fixtures are properly constrained at every assembly step. A case study on a simple frame structure is presented to demonstrate the method. Note to Practitioners-Achieving dimensional integrity of complex assemblies is a very demanding task due to the dimensional variations of parts and their propagation. Keys to achieving the goal are to adjust critical dimensions using proper fixtures and joint configurations and to minimize unpredictable deformations caused by overconstrained parts, such that assembled products can be robust to dimensional variations of parts. Equally important are arranging fixtures and sequencing assembly steps as these are what really define which critical dimension is adjusted and which subassemblies are put together on what fixture at each assembly step. In this paper, we propose a top-down decomposition-based approach that generates assembly design, assembly sequence, and fixture plan ensuring adjustability for critical dimensions and properly constrained subassemblies at every assembly step. The method does not only prevent costly trial and error following bottom-up approaches, but also enumerates all feasible solutions for a given product geometry and critical dimensions. As the number of solutions can be fairly large, for real-word application, it is crucial to incorporate practical constraints and to identify other important criteria to search optimal designs.
Dirty Paper Coding for the MIMO cognitive radio channel with imperfect CSIT

A Dirty Paper Coding (DPC) based transmission scheme for the Gaussian multiple-input multiple-output (MIMO) cognitive radio channel (CRC) is studied when there is imperfect and perfect channel knowledge at the transmitters (CSIT) and the receivers, respectively. In particular, the problem of optimizing the sum-rate of the MIMO CRC over the transmit covariance matrices is dealt with. Such an optimization, under the DPC-based transmission strategy, needs to be performed jointly with an optimization over the inflation factor. To this end, first the problem of determination of inflation factor over the MIMO channel Y = H 1 X +H 2 S +Z with imperfect CSIT is investigated. For this problem, two iterative algorithms, which generalize the corresponding algorithms proposed for the channel Y = H(X +S)+Z, are developed. Later, the necessary conditions for maximizing the sum-rate of the MIMO CRC over the transmit covariances for a given choice of inflation factor are derived. Using these necessary conditions and the algorithms for the determination of the inflation factor, an iterative, numerical algorithm for the joint optimization is proposed. Some interesting observations are made from the numerical results obtained from the algorithm. Furthermore, the high-SNR sum-rate scaling factor achievable over the CRC with imperfect CSIT is obtained.
Measuring Social Networks' Effects on Agricultural Technology Adoption

Technological improvements, perhaps especially in agriculture, drive sustainable advances in labor productivity, incomes, food security and general economic growth. But improved technologies are not adopted immediately, randomly or completely throughout a population...
The LiftLT: fast-lapped transforms via lifting steps

This paper introduces a class of multiband linear phase-lapped biorthogonal transforms with fast, VLSI-friendly implementations via lifting steps called the LiftLT. The transform is based on a lattice structure that robustly enforces both linear phase and perfect reconstruction properties. The lattice coefficients are parameterized as a series of lifting steps, providing fast, efficient, in-place computation of the transform coefficients. The new transform is designed for applications in image and video coding. Compared to the popular 8/spl times/8 DCT, the 8/spl times/16 LiftLT only requires one more multiplication, 22 more additions, and six more shifting operations. However, image coding examples show that the LiftLT is far superior to the DCT in both objective and subjective coding performance. Thanks to properly designed overlapping basis functions, the LiftLT can completely eliminate annoying blocking artifacts. In fact, the novel LT's coding performance consistently surpasses that of the much more complex 9/7-tap biorthogonal wavelet with floating-point coefficients. More importantly, the transform's block-based nature facilitates one-pass sequential block coding, region-of-interest coding/decoding, and parallel processing.
NEUROCOGNITION IN FIRST-EPISODE SCHIZOPHRENIA: A META-ANALYTIC REVIEW

Compromised neurocognition is a core feature of schizophrenia. Following Heinrichs and Zakzanis's (1998) seminal meta-analysis of middle-aged and predominantly chronic schizophrenia samples, the aim of this study is to provide a meta-analysis of neurocognitive findings from 47 studies of first-episode (FE) schizophrenia published through October 2007. The meta-analysis uses 43 separate samples of 2,204 FE patients with a mean age of 25.5 and 2,775 largely age- and gender-matched control participants. FE samples demonstrated medium-to-large impairments across 10 neurocognitive domains (mean effect sizes from -0.64 to -1.20). Findings indicate that impairments are reliably and broadly present by the FE, approach or match the degree of deficit shown in well-established illness, and are maximal in immediate verbal memory and processing speed. Larger IQ impairments in the FE compared to the premorbid period, but comparable to later phases of illness suggests deterioration between premorbid and FE phases followed by deficit stability at the group level. Considerable heterogeneity of effect sizes across studies, however, underscores variability in manifestations of the illness and a need for improved reporting of sample characteristics to support moderator variable analyses.
Expanders via random spanning trees

Motivated by the problem of routing reliably and scalably in a graph, we introduce the notion of a splicer, the union of spanning trees of a graph. We prove that for any bounded-degree n-vertex graph, the union of two random spanning trees approximates the expansion of every cut of the graph to within a factor of O(log n). For the random graph Gn, p, for p = Ω(log n/n), we give a randomized algorithm for constructing two spanning trees whose union is an expander. This is suggested by the case of the complete graph, where we prove that two random spanning trees give an expander. The construction of the splicer is elementary; each spanning tree can be produced independently using an algorithm by Aldous and Broder: A random walk in the graph with edges leading to previously unvisited vertices included in the tree. Splicers also turn out to have applications to graph cut-sparsification where the goal is to approximate every cut using only a small subgraph of the original graph. For random graphs, splicers provide simple algorithms for sparsifiers of size O(n) that approximate every cut to within a factor of O(log n).
Earnings, performance, and nationality discrimination in a highly competitive labor market as an analysis of the English professional soccer league.

This article tests for the existence of nationality discrimination in the English professional soccer league. Although wage equations have typically been used by labor economists to identify discrimination, the approach may be plagued by unobserved productivity characteristics that are correlated with race and ethnicity, resulting in biased estimates of discrimination. This paper utilizes a "market test" approach to determine the existence of nationality discrimination. The results provide some evidence that players from South America may receive preferential labor market treatment, but this is only evident in the Premier (or highest) division of the league. In addition, this labor market discrimination appears to be a rational response from owners who observe increased attendance with a larger presence of South American players.
Sensitivity of International Blocs' Trade Effect to Alternative Specifications of the Gravity Equation

There are so many versions of the gravity model in the international trade literature that their results on trade effects inevitably vary even for the same international blocs. This paper evaluates...
A Framework for Efficient and Composable Oblivious Transfer

We propose a simple and general framework for constructing oblivious transfer (OT) protocols that are efficient, universally composable, and generally realizableunder any one of a variety of standard number-theoretic assumptions, including the decisional Diffie-Hellman assumption, the quadratic residuosity and decisional composite residuosity assumptions, and worst-caselattice assumptions. Our OT protocols are round-optimal (one message each way), quite efficient in computation and communication, and can use a single common string for an unbounded number of executions between the same sender and receiver. Furthermore, the protocols can provide statisticalsecurity to either the sender or the receiver, simply by changing the distribution of the common string. For certain instantiations of the protocol, even a common uniformly randomstring suffices. Our key technical contribution is a simple abstraction that we call a dual-modecryptosystem. We implement dual-mode cryptosystems by taking a unified view of several cryptosystems that have what we call "messy" public keys, whose defining property is that a ciphertext encrypted under such a key carries no information(statistically) about the encrypted message. As a contribution of independent interest, we also provide a multi-bit amortizedversion of Regev's lattice-based cryptosystem (STOC 2005) whose time and space complexity are improved by a linear factor in the security parameter n. The resulting amortized encryption and decryption times are only $\tilde{O}(n)$ bit operations per message bit, and the ciphertext expansion can be made as small as a constant; the public key size and underlying lattice assumption remain essentially the same.
Representing boolean functions using polynomials: more can offer less

Polynomial threshold gates are basic processing units of an artificial neural network. When the input vectors are binary vectors, these gates correspond to Boolean functions and can be analyzed via their polynomial representations. In practical applications, it is desirable to find a polynomial representation with the smallest number of terms possible, in order to use the least possible number of input lines to the unit under consideration. For this purpose, instead of an exact polynomial representation, usually the sign representation of a Boolean function is considered. The non-uniqueness of the sign representation allows the possibility for using a smaller number of monomials by solving a minimization problem. This minimization problem is combinatorial in nature, and so far the best known deterministic algorithm claims the use of at most 0.75 × 2n of the 2n total possible monomials. In this paper, the basic methods of representing a Boolean function by polynomials are examined, and an alternative approach to this problem is proposed. It is shown that it is possible to use at most 0.5 × 2n = 2n-1 monomials based on the {0, 1} binary inputs by introducing extra variables, and at the same time keeping the degree upper bound at n. An algorithm for further reduction of the number of terms that used in a polynomial representation is provided. Examples show that in certain applications, the improvement achieved by the proposed method over the existing methods is significant.
Asymptotics of the Energy of Sections of Greedy Energy Sequences on the Unit Circle, and Some Conjectures for General Sequences

In this paper we investigate the asymptotic behavior of the Riesz s-energy of the first N points of a greedy s-energy sequence on the unit circle, for all values of s in the range $$0\le s<\infty $$ (identifying as usual the case $$s=0$$ with the logarithmic energy). In the context of the unit circle, greedy s-energy sequences coincide with the classical Leja sequences constructed using the logarithmic potential. We obtain first-order and second-order asymptotic results. The key idea is to express the Riesz s-energy of the first N points of a greedy s-energy sequence in terms of the binary representation of N. Motivated by our results, we pose some conjectures for general sequences on the unit circle.
The many roles of computing on the campus

At Dartmouth College the "computer" has become an essential component of the university community comparable to the library in importance, size, and diversity of application. While such a statement no longer raises eyebrows, in few other cases has the extent of the infusion of computing into the life of the university community been as great, or as painless, as at Dartmouth. The purpose of this paper is to report some of the many ways in which computing has been found useful in teaching and research at Dartmouth, and to claim that these almost revolutionary (though almost painless) developments were generated primarily by having freely available to all students and faculty a general purpose time-sharing system equipped with a simple and easy to learn language (BASIC), and a simple and friendly user interface.
History of electric vehicles in General Motors

The propulsion systems being used by General Motors in different electric vehicle projects are described, and the performances achieved are presented. The past projects discussed are electrovan, an electric truck for military application, STIR-LEC I (a Stirling electric hybrid car), the GM512 series car. The AT&T van, and the Electrovette. Current projects such as IMPACT and the electric shuttle bus are also discussed. The IMPACT was developed because of a concern for air quality. The technology of impact is based on advanced propulsion system technology and is suitable for mass production at affordable costs. >
The Conscription of Wealth: Mass Warfare and the Demand for Progressive Taxation

The dominant narrative of the politics of redistribution in political sci- ence and economics highlights the signature role of the rise of electoral democracy and the development of political parties that mobilize working-class groups+ We argue in this article that this narrative ignores the critical role played by mass warfare in the development of redistributive public policies+ Focusing attention on the determi- nants of progressive taxation, we argue that mobilization for mass warfare led to demands for increased taxation of the wealthy to more fairly distribute the burden for the war effort+ We then show empirically that during the past century, mass mobi- lization for war has been associated with a notable increase in tax progressivity+ In the absence of war, neither the establishment of universal suffrage, nor the arrival of political control by parties of the left is systematically associated with large increases in tax progressivity+ In making these arguments, we devote particular attention to a "difference-in-differences" comparison of participants and nonparticipants in World War I+ Those who have made fortunes out of the war must pay for the war; and Labour will insist upon heavily graduated direct taxation with a raising of the exemption limit+ That is what Labour means by the Conscription of Wealth+
Topological approach to Alice electrodynamics

We analyze the unlocalized “Cheshire charge” carried by “Alice strings.” The magnetic charge on a string loop is carefully defined, and the transfer of magnetic charge from a monopole to a string loop is analyzed using global topological methods. A semiclassical theory of electric charge transfer is also described.
Novel 2-amino-4-oxo-5-arylthio-substituted-pyrrolo[2,3-d]pyrimidines as nonclassical antifolate inhibitors of thymidylate synthase.

Abstract A series of 17 novel 2-amino-4-oxo-5-[(substituted phenyl)thio]pyrrolo[2,3- d ]pyrimidines were synthesized as potential inhibitors of thymidylate synthase (TS) and as antitumor agents. The analogues contain a variety of electron withdrawing substituents on the phenyl ring of the side chain and were evaluated as inhibitors of human TS (hTS) and Escherichia coli TS and of human and E. coli dihydrofolate reductase (DHFR). The analogues 14 , 17 , and 18 were potent inhibitors of hTS with IC 50 values of 0.28, 0.21, and 0.22 μM, respectively, and were more potent than the clinically used ZD1694, 2 and LY231514, 3 against human TS.
Shielding Heterogeneous MPSoCs From Untrustworthy 3PIPs Through Security- Driven Task Scheduling

Multiprocessor system-on-chip (MPSoC) platforms face some of the most demanding security concerns, as they process, store, and communicate sensitive information using third-party intellectual property (3PIP) cores. The complexity of MPSoC makes it expensive and time consuming to fully analyze and test during the design stage. This has given rise to the trend of outsourcing design and fabrication of 3PIP components, that may not be trustworthy. To protect MPSoCs against malicious modifications, we impose a set of security-driven diversity constraints into the task scheduling step of the MPSoC design process, enabling the system to detect the presence of malicious modifications or to mute their effects during application execution. We pose the security-constrained MPSoC task scheduling as a multidimensional optimization problem, and propose a set of heuristics to ensure that the introduced security constraints can be fulfilled with a minimum impact on the other design goals such as performance and hardware. Experimental results show that without any extra cores, security constraints can be fulfilled within four vendors and 81% overhead in schedule length.
Azido-Containing aryl β-Diketo acid HIV-1 integrase inhibitors

Aryl β-diketo acids (ADK) comprise a general class of potent HIV-1 integrase (IN) inhibitors, which can exhibit selective inhibition of strand transfer reactions in extracellular recombinant IN assays and provide potent antiviral effects in HIV-infected cells. Recent studies have shown that polycyclic aryl or aryl rings bearing aryl-containing substituents are components of potent members of this class. Reported herein is the first use of azido functionality as an aryl replacement in β-diketo acid IN inhibitors. The ability of azido-containing inhibitors to exhibit potent inhibition of IN and antiviral protection in HIV-infected cells, renders the azide group of potential value in the further development of ADK-based IN inhibitors.
Regiocontrolled synthesis of (hetero)aryl and alkenyl dehydropyrrolidines, dehydropiperidines and azepenes by Ru-catalyzed, heteroatom-directed α-C-H activation/cross-coupling of cyclic enamides with boronic acids.

The synthesis of α-aryl and alkenyl pyrrolidine-, piperidine-, and azepane derivatives, through the intermediacy of cyclic enamides is described. The desired outcome is achieved through ruthenium-catalyzed, site-selective sp2 C–H activation/cross-coupling with aryl and alkenyl boronic acids. The regioselectivity (α-sp2vs. α-sp3vs. β-sp2 C–H functionalization) is governed by the rate differences between sp2 and sp3 C–H activation and the necessity for chelation between the ruthenium metal and the carbonyl directing group.
Revisiting the Impacts of Teachers

Author(s): Rothstein, Jesse | Abstract: Chetty, Friedman, and Rockoff (2014a, 2014b) study value-added (VA) measures of teacher effectiveness. CFR (2014a) exploits teacher switching as a quasi-experiment, concluding that student sorting creates negligible bias in VA scores. CFR (2014b) finds VA scores are useful proxies for teachers’ effects on students’ long-run outcomes. I successfully reproduce each in North Carolina data. But I find that the quasi-experiment is invalid, as teacher switching is correlated with changes in student preparedness. Adjusting for this, I find moderate bias in VA scores, perhaps 10-35% as large, in variance terms, as teachers’ causal effects. Long-run results are sensitive to controls and cannot support strong conclusions.
Building authentic power: a study of the campaign to repeal Connecticut's death penalty

ABSTRACTPersistent public support for capital punishment and constraints on political elites in the US breed skepticism over grassroots campaigns’ ability to have much impact on this policy. Andrew Hammel advances this point in his study of successful efforts in Europe to repeal the death penalty and the lack of success in the US, where opportunities for repeal seem minimal. We challenge this view by offering the 2012 campaign to repeal Connecticut's death penalty as a counterexample. Drawing on legislative, campaign, and media source documents, we provide a case study of this campaign. Particularly important in the Connecticut campaign was the participation of murder victims’ families and communities of color, who exercised what we term authentic power: the extent that a group harmed by a policy can get policy-makers and other government officials to acknowledge this harm and, ultimately, to change the policy to the group's benefit. Elites face limits in their ability to end the death penalty and enact c...
PhaseLift is robust to a constant fraction of arbitrary errors

Abstract Consider the task of recovering an unknown n-vector from phaseless linear measurements. This nonconvex problem may be convexified into a semidefinite rank-one matrix recovery problem, known as PhaseLift. Under a linear number of Gaussian measurements, PhaseLift recovers the unknown vector exactly with high probability. Under noisy measurements, the solution to a variant of PhaseLift has error proportional to the l 1 norm of the noise. In the present paper, we study the robustness of this variant of PhaseLift to gross, arbitrary corruptions. We prove that PhaseLift can tolerate noise and a small, fixed fraction of gross errors, even in the highly underdetermined regime where there are only O ( n ) measurements. The lifted phase retrieval problem can be viewed as a rank-one robust Principal Component Analysis (PCA) problem under generic rank-one measurements. From this perspective, the proposed convex program is simpler than the semidefinite version of the sparse-plus-low-rank formulation standard in the robust PCA literature. Specifically, the rank penalization through a trace term is unnecessary, and the resulting optimization program has no parameters that need to be chosen.
Probing the fermionic Higgs portal at lepton colliders

We study the sensitivity of future electron-positron colliders to UV completions of the fermionic Higgs portal operator $$ {H}^{\dagger }{H}_{\overline{\chi}\chi } $$ . Measurements of precision electroweak S and T parameters and the e + e − → Zh cross-section at the CEPC, FCC-ee, and ILC are considered. The scalar completion of the fermionic Higgs portal is closely related to the scalar Higgs portal, and we summarize existing results. We devote the bulk of our analysis to a singlet-doublet fermion completion. Assuming the doublet is sufficiently heavy, we construct the effective field theory (EFT) at dimension-6 in order to compute contributions to the observables. We also provide full one-loop results for S and T in the general mass parameter space. In both completions, future precision measurements can probe the new states at the (multi-)TeV scale, beyond the direct reach of the LHC.
How I Approach Retroflexion and Prevention of Right-Sided Colon Cancer Following Colonoscopy.

How I Approach Retroflexion and Prevention of Right-Sided Colon Cancer Following Colonoscopy
Network Coding over SATCOM: Lessons Learned

Satellite networks provide unique challenges that can restrict users’ quality of service. For example, high packet erasure rates and large latencies can cause significant disruptions to applications such as video streaming or voice-over-IP. Network coding is one promising technique that has been shown to help improve performance, especially in these environments. However, implementing any form of network code can be challenging. This paper will use an example of a generation-based network code and a sliding-window network code to help highlight the benefits and drawbacks of using one over the other. In-order packet delivery delay, as well as network efficiency, will be used as metrics to help differentiate between the two approaches. Furthermore, lessoned learned during the course of our research will be provided in an attempt to help the reader understand when and where network coding provides its benefits.
CONTEMPORARY BONE LOSS OPTIONS: REBUILD, REINFORCE AND AUGMENT

The amount of bone loss due to implant failure, loosening, or osteolysis can vary greatly and can have a major impact on reconstructive options during revision total knee arthroplasty. Massive bone loss can threaten ligamentous attachments in the vicinity of the knee and may require use of components with additional constraint to compensate for associated ligamentous instability. Classification of bone defects can be helpful in predicting the complexity of the reconstruction required and in facilitating preoperative planning and implant selection. One very helpful classification of bone loss associated with TKA is the Anderson Orthopaedic Research Institute (AORI) Bone Defect Classification System. This system provides the means to compare the location and extent of femoral and tibial bone loss encountered during revision surgery. In general, the higher grade defects (Type IIb or III) on both the femoral and tibial sides are more likely to require stemmed components, and may require the use of either structural graft or large augments to restore support for currently available modular revision components. Custom prostheses were previously utilised for massive defects of this sort, but more recently have been supplanted by revision TKA component systems with or without special metal augments or structural allograft. Options for bone defect management are as follows: 1) fill with cement, 2) fill with cement supplemented by screws or K-wires, 3) Morsellised bone grafting (for smaller, especially contained cavitary defects), 4) Small segment structural bone graft, 5) Impaction grafting, 6) Large prosthetic augments (cones), 7) Massive structural allograft-prosthetic composites (APC), 8) Custom implants. It is very helpful for revision surgeons to have a variety of reconstructive options available, even despite a well thought-out preoperative plan. Preoperative planning is important but the plan that results may require alteration during the course of the surgery to accommodate bone defects which are either less or more severe than thought pre-operatively, and to adjust to variable quality and extent of host bone remaining, as this provides the mechanical platform for the reconstruction. Maximising support on intact host bone is a fundamental principle to successful reconstruction and frequently requires extending fixation to the adjacent diaphysis. Bone defect management during revision total knee arthroplasty can provide a wide range of challenges from relatively trivial problems with small defects manageable with cement or small amounts of cancellous graft to massive deficiencies that may defy reconstruction except with allograft prosthetic components or large segmental replacing tumor-type implants. The more common Type II deficiencies increasingly seen in the context of particulate driven osteolysis demand a wide range of implant and bone graft options so that an individualised reconstruction can be accomplished for that particular patient based on bone defect size, location, quality of bone remaining, ligamentous status, and anticipated patient demands.
Speculation and Volatility Spillover in the Crude Oil and Agricultural Commodity Markets: A Bayesian Analysis

This paper assesses factors that potentially influence the volatility of crude oil prices and the possible linkage between this volatility and agricultural commodity markets. Stochastic volatility models are applied to weekly crude oil, corn, and wheat futures prices from November 1998 to January 2009. Model parameters are estimated using Bayesian Markov Chain Monte Carlo methods. Speculation, scalping, and petroleum inventories are found to be important in explaining the volatility of crude oil prices. Several properties of crude oil price dynamics are established, including mean-reversion, an asymmetry between returns and volatility, volatility clustering, and infrequent compound jumps. We find evidence of volatility spillover among crude oil, corn, and wheat markets after the fall of 2006. This can be largely explained by tightened interdependence between crude oil and these commodity markets induced by ethanol production.
Generating Configurable Hardware from Parallel Patterns

In recent years the computing landscape has seen an increasing shift towards specialized accelerators. Field programmable gate arrays (FPGAs) are particularly promising for the implementation of these accelerators, as they offer significant performance and energy improvements over CPUs for a wide class of applications and are far more flexible than fixed-function ASICs. However, FPGAs are difficult to program. Traditional programming models for reconfigurable logic use low-level hardware description languages like Verilog and VHDL, which have none of the productivity features of modern software languages but produce very efficient designs, and low-level software languages like C and OpenCL coupled with high-level synthesis (HLS) tools that typically produce designs that are far less efficient. Functional languages with parallel patterns are a better fit for hardware generation because they provide high-level abstractions to programmers with little experience in hardware design and avoid many of the problems faced when generating hardware from imperative languages. In this paper, we identify two important optimizations for using parallel patterns to generate efficient hardware: tiling and metapipelining. We present a general representation of tiled parallel patterns, and provide rules for automatically tiling patterns and generating metapipelines. We demonstrate experimentally that these optimizations result in speedups up to 39.4× on a set of benchmarks from the data analytics domain.
Coastal Ecosystem Services of the Gulf of Mexico: Does their Value Depend on the Providing Habitat?

Our study is the first to test whether ecosystem service values depend on the providing habitat and is the first study using primary data to compare value estimates across locations which are ex ante more likely to yield similar value estimates than locations in existing studies. We find that about half of value estimate comparisons across locations result in a rejection of value equality when the providing habitat is held constant and that about one fourth of comparisons across habitats but within the same location result in a rejection of equality.
Polarization Control via He-Ion Beam Induced Nanofabrication in Layered Ferroelectric Semiconductors

Rapid advances in nanoscience rely on continuous improvements of material manipulation at near-atomic scales. Currently, the workhorse of nanofabrication is resist-based lithography and its various derivatives. However, the use of local electron, ion, and physical probe methods is expanding, driven largely by the need for fabrication without the multistep preparation processes that can result in contamination from resists and solvents. Furthermore, probe-based methods extend beyond nanofabrication to nanomanipulation and to imaging which are all vital for a rapid transition to the prototyping and testing of devices. In this work we study helium ion interactions with the surface of bulk copper indium thiophosphate CuM(III)P2X6 (M = Cr, In; X= S, Se), a novel layered 2D material, with a Helium Ion Microscope (HIM). Using this technique, we are able to control ferrielectric domains and grow conical nanostructures with enhanced conductivity whose material volumes scale with the beam dosage. Compared to the copper indium thiophosphate (CITP) from which they grow, the nanostructures are oxygen rich, sulfur poor, and with virtually unchanged copper concentration as confirmed by energy-dispersive X-ray spectroscopy (EDX). Scanning electron microscopy (SEM) imaging contrast as well as scanning microwave microscopy (SMM) measurements suggest enhanced conductivity in the formed particles, whereas atomic force microscopy (AFM) measurements indicate that the produced structures have lower dissipation and are softer as compared to the CITP.
Through-the-wall radar detection analysis via numerical modeling of Maxwell's equations

The problem of through-the-wall imaging is considered. A numerical method for Maxwell's Equations is developed and implemented with the goal of generating an approximate solution to this problem. The forward problem is solved using the Yee Scheme, and this solver is used in the inverse problem of detecting and analyzing objects inside a room, with no direct vision of the inside. It is shown how different sizes and shapes of objects have different responses to source waves, and these differences can be used to approximate the object. Numerical results show that this reconstruction procedure gives an accurate approximation to the boundary of the object. FDTD solver for Through-the-Wall imaging is developed.Perfectly Matched Layers and Subpixel smoothing are implemented to maintain accuracy.Inverse problem of object detection is analyzed.Objects of differing sizes and shapes are detected with this method.
A Tale of the Good and Bad: Remodeling of the Microtubule Network in the Brain by Cdk5

Cdk5, a cyclin-dependent kinase family member, is a global orchestrator of neuronal cytoskeletal dynamics. During embryogenesis, Cdk5 is indispensable for brain development. In adults, it is essential for numerous neuronal processes, including higher cognitive functions such as learning and memory formation, drug addiction, pain signaling, and long-term behavior changes through long-term potentiation and long-term depression, all of which rely on rapid alterations in the cytoskeleton. Cdk5 activity becomes deregulated in various brain disorders, including Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, attention-deficit hyperactivity disorder, epilepsy, schizophrenia, and ischemic stroke; these all result in profound remodeling of the neuronal cytoskeleton. This Commentary specifically focuses on the pleiotropic contribution of Cdk5 in regulating neuronal microtubule remodeling. Because the vast majority of the physiological substrates of Cdk5 are associated with the neuronal cytoskeleton, our emphasis is on the Cdk5 substrates, such as CRMP2, stathmin, drebrin, dixdc1, axin, MAP2, MAP1B, doublecortin, kinesin-5, and tau, that have allowed to unravel the molecular mechanisms through which Cdk5 exerts its divergent roles in regulating neuronal microtubule dynamics, both in healthy and disease states.
Theory and Modeling of Asymmetric Catalytic Reactions

ConspectusModern density functional theory and powerful contemporary computers have made it possible to explore complex reactions of value in organic synthesis. We describe recent explorations of mechanisms and origins of stereoselectivities with density functional theory calculations. The specific functionals and basis sets that are routinely used in computational studies of stereoselectivities of organic and organometallic reactions in our group are described, followed by our recent studies that uncovered the origins of stereocontrol in reactions catalyzed by (1) vicinal diamines, including cinchona alkaloid-derived primary amines, (2) vicinal amidophosphines, and (3) organo-transition-metal complexes. Two common cyclic models account for the stereoselectivity of aldol reactions of metal enolates (Zimmerman–Traxler) or those catalyzed by the organocatalyst proline (Houk–List). Three other models were derived from computational studies described in this Account.Cinchona alkaloid-derived primary amines an...
Trade-Time Measures of Liquidity

Dramatic microstructure changes in equity markets have made standard liquidity measures less accurate proxies for trading costs. We develop trade-time liquidity measures that reflect per-dollar price impacts of fixed-dollar volumes. Our measures better capture institutional trading costs and better explain the cross-section of returns than do standard measures, especially in recent years. Despite improvements in measures of market quality, expected trading costs have explanatory power for the cross-section of expected returns: we obtain monthly liquidity premium estimates of 5.3 bp for expected returns and 2.4 bp for risk-adjusted returns. Estimated premiums rise after the financial crisis and remain high thereafter.
A one-pot method for the preparation of 2,5-diarylthiophene-1-oxides from arylacetylenes

Abstract 2,5-Diarylthiophene-1-oxides have been prepared from readily available arylacetylene precursors via zirconacyclopentadiene intermediates. The isolated yields of the desired thiophene-1-oxides are comparable to those obtained from the oxidation of thiophene derivatives while avoiding the formation of over-oxidation products. Furthermore, this route offers broader versatility than commonly used methods by providing products outfitted with electron-donating or electron-withdrawing groups with very little variation in isolated product yields. Finally, this strategy provides access to products containing functional groups that are not compatible with oxidation conditions.
Silicone Rubber: A New Diffusion Property Useful for General Anesthesia

Ether, nitrous oxide, halothane, and cyclopropane diffuse through silicone rubber. General anesthesia can be produced in dogs by passing the vapors of any of these anesthetic agents through a coil of silicone rubber tubing, each end of which is placed in an artery and vein. Potential applications include a new method for general anesthesia and a simple accurate vaporizer for halothane.
LiCa3As2H and Ca14As6X7 (X = C, H, N): Two New Arsenide Hydride Phases Grown from Ca/Li Metal Flux

The reaction of arsenic with sources of light elements in a Ca/Li melt leads to the formation of two new arsenide hydride phases. The predominant phase Ca14As6X7 (X = C4–, N3–, H–) exhibits a new tetragonal structure type in the space group P4/mbm (a = 15.749(1) A, c = 9.1062(9) A, Z = 4, R1 = 0.0150). The minor phase LiCa3As2H also has a new structure type in the orthorhombic space group Pnma (a = 11.4064(7) A, b = 4.2702(3) A, c = 11.8762(8)A, Z = 4, R1 = 0.0135). Both phases feature hydride and arsenide anions separated by calcium cations. The red color of these compounds indicates they should be charge-balanced. DOS calculations on LiCa3As2H confirm a band gap of 1.4 eV; UV–vis spectroscopy on Ca14As6X7 shows a band gap of 1.6 eV. Single-crystal neutron diffraction studies were necessary to determine the mixed occupancy of carbon, nitrogen, and hydrogen anions on the six light-element sites in Ca14As6X7; these data indicated an overall stoichiometry of Ca14As6C0.445N1.135H4.915.
Pharmacophore-Based Similarity Scoring for DOCK

Pharmacophore modeling incorporates geometric and chemical features of known inhibitors and/or targeted binding sites to rationally identify and design new drug leads. In this study, we have encoded a three-dimensional pharmacophore matching similarity (FMS) scoring function into the structure-based design program DOCK. Validation and characterization of the method are presented through pose reproduction, crossdocking, and enrichment studies. When used alone, FMS scoring dramatically improves pose reproduction success to 93.5% (∼20% increase) and reduces sampling failures to 3.7% (∼6% drop) compared to the standard energy score (SGE) across 1043 protein–ligand complexes. The combined FMS+SGE function further improves success to 98.3%. Crossdocking experiments using FMS and FMS+SGE scoring, for six diverse protein families, similarly showed improvements in success, provided proper pharmacophore references are employed. For enrichment, incorporating pharmacophores during sampling and scoring, in most cases,...
The daphniphyllum alkaloids: total synthesis of (-)-calyciphylline N.

Presented here is a full account on the development of a strategy culminating in the first total synthesis of the architecturally complex daphniphyllum alkaloid, (−)-calyciphylline N. Highlights of the approach include a highly diastereoselective, intramolecular Diels–Alder reaction of a silicon-tethered acrylate; an efficient Stille carbonylation of a sterically encumbered vinyl triflate; a one-pot Nazarov cyclization/proto-desilylation sequence; and the chemoselective hydrogenation of a fully substituted diene ester.
γ,δ,ε-C(sp3)–H Functionalization through Directed Radical H-Abstraction

Aliphatic amides are selectively functionalized at the γ- and δ-positions through directed radical 1,5 and 1,6 H-abstractions, respectively. The initially formed γ- or δ-lactams are intercepted by N-iodosuccinimide and trimethylsilyl azide, leading to double and triple C–H functionalizations at the γ-, δ-, and e-positions. This new reactivity is exploited to convert alkyls into amino alcohols and allylic amines.
Biometric Systems for User Authentication

Authenticating the identity of users is a critical issue in information security. Biometrics is known for recognizing users based on their physiological or behavioral traits as identifiers and these cannot be easily stolen unlike passwords or ID cards. Biometrics could be employed as the primary means for authentication, called user identification, as well as a complementary (secondary) method for authentication, known as user verification. Biometric traits that cannot be easily forged and are supposedly unique for each user can form the basis of techniques for user identification. Biometric traits need not be unique for each user, but, can be used to validate whether a user is whom he/she claims to be form the basis for user verification techniques. The first half of the chapter describes several biometric techniques used for identification and verification and compares them with respect to different operating parameters. In addition, the different components (constituent blocks) of a biometric system and the performance metrics used to analyze the effectiveness of biometric systems are also discussed. The second half of the chapter focuses on the security aspects of biometric systems, especially spoofing attacks and a solution to enhance the security and effectiveness through multi-biometric systems.
Approach to dark spin cooling in a diamond nanocrystal.

Using a Hartman–Hahn protocol, we demonstrate spin polarization transfer from a single, optically polarized nitrogen-vacancy (NV) center to the ensemble of paramagnetic defects hosted by an individual diamond nanocrystal. Owing to the strong NV–bath coupling, the transfer takes place on a short, microsecond time scale. Upon fast repetition of the pulse sequence, we observe strong polarization transfer blockade, which we interpret as an indication of spin bath cooling. Numerical simulations indicate that the spin bath polarization is nonuniform throughout the nanoparticle, averaging approximately 5% over the crystal volume, but reaching up to 25% in the immediate vicinity of the NV. These observations may prove relevant to the planning of future bath-assisted magnetometry tests.
Transformation of Energy by Rubber

Abstract The data which have been presented indicate that elasticity is a property of rubber which persists through vulcanization and is not created to any great extent. The physical state of the rubber after any period of cure depends on the balance between suppression of plastic properties either directly or indirectly through the influence of combination of sulfur, and the creation of plastic properties through the influence of heat. It is probable that sulfur also combines at a slower rate with the elastic portion of the rubber and finally results in a product of almost no mechanical strength. The transformation of energy by rubber depends upon the condition of the rubber as well as on the condition of the test. Heat liberated by elastic strain can be transformed almost quantitatively into mechanical work. Heat due to internal-frictional resistance which will be caused by both plastic and elastic flow is not reversible. Any reduction in time required for the transfer of energy reduces the amount lost ...
Catalytic Anti-Markovnikov Hydrobromination of Alkynes

We have developed the first catalytic method for anti-Markovnikov hydrobromination of alkynes. The reaction affords terminal E-alkenyl bromides in high yield and with excellent regio- and diastereoselectivity. Both aryl- and alkyl-substituted terminal alkynes can be used as substrates. Furthermore, the reaction conditions are compatible with a wide range of functional groups, including esters, nitriles, epoxides, aryl boronic esters, terminal alkenes, silyl ethers, aryl halides, and alkyl halides. A preliminary study of the reaction mechanism suggests that the hydrobromination reaction involves hydrocupration of an alkyne, followed by the bromination of the alkenyl copper intermediate. This study also suggests that 2-tert-butyl potassium phenoxide functions as a mild catalyst turnover reagent and provides a better understanding of the unique effectiveness of (BrCl2C)2 among brominating reagents.
Discovery and optimization of non-steroidal FXR agonists from natural product-like libraries.

The efficient regulation of cholesterol biosynthesis, metabolism, acquisition, and transport is an essential component of lipid homeostasis. The farnesoid X receptor (FXR) is a transcriptional sensor for bile acids, the primary product of cholesterol metabolism. Accordingly, the development of potent, selective, small molecule agonists, partial agonists, and antagonists of FXR would be an important step in further deconvoluting FXR physiology. Herein, we describe the development of four novel classes of potent FXR activators originating from natural product-like libraries. Initial screening of a 10000-membered, diversity-orientated library of benzopyran containing small molecules for FXR activation utilizing a cell-based reporter assay led to the identification of several lead compounds possessing low micromolar activity (EC50's = 5–10 µM). These compounds were systematically optimized employing parallel solution-phase synthesis and solid-phase synthesis to provide four classes of compounds that potently activate FXR. Two series of compounds, bearing stilbene or biaryl moieties, contain members that are the most potent FXR agonists reported to date in cell-based assays. These compounds may find future utility as chemical tools in studies aimed at further defining the physiological role of FXR and discovering potential therapeutic agents for the treatment of diseases linked to cholesterol and bile acid metabolism and homeostasis.