cssi/SciSciGPT-SciSciNet huggingface dataset:
Productive dialog during collaborative problem solving

Collaboration is an important problem-solving skill; however, novice collaboration generally benefits from some kind of support. One possibility for supporting productive conversations between collaborators is to encourage pairs of students to provide explanations for their problem-solving steps. To test this possibility, we contrasted individuals who were instructed to self-explain problem-solving steps with dyads who were instructed to jointly explain problem-solving steps in the context of an intelligent tutoring system (ITS). The results suggest that collaboratively developed explanations prompted students to remediate their errors in dialog, as opposed to relying on the ITS for assistance, which is provided in the form of on-demand hints. The paper concludes with a discussion about implications for combining proven learning interventions.
The Impact of Infrared Array Technology on Astronomy

Over the past ten years a technological revolution has occurred in the development of two-dimensional infrared array detectors for astronomical observations. The wide application of these arrays for both ground-based and space observations has resulted in a profound change in the capabilities and perspective for infrared astronomy, resulting in new views of the infrared sky. A review will be presented describing these detectors, the numerous advantages they provide for astronomical observations, the present state of array technology, and the potential for future growth.
Symmetric Capacity of the Gaussian Interference Channel With an Out-of-Band Relay to Within 1.15 Bits

This paper studies the Gaussian interference channel (IC) with a relay, which transmits and receives in a band that is orthogonal to the IC. The channel associated with the relay is thus an out-of-band relay channel (OBRC). The focus is on a symmetric channel model, in order to assess the fundamental impact of the OBRC on the signal interaction of the IC, in the simplest possible setting. First, the linear deterministic model is investigated and the sum capacity of this channel is established for all possible channel parameters. In particular, it is observed that the impact of OBRC, as its links get stronger, is similar to that of output feedback for the IC. The insights obtained from the deterministic model are then used to design achievable schemes for the Gaussian model. The interference links are classified as extremely strong, very strong, strong, moderate, weak, and very weak. For strong and moderate interference, separate encoding is near optimal. For very strong and extremely strong interference, the interference links provide side information to the destinations, which can help the transmission through the OBRC. For weak or very weak interference, an extension of the Han-Kobayashi scheme for the IC is utilized, where the messages are split into common and private. To achieve higher rates, it is beneficial to further split the common message into two parts, and the OBRC plays an important role in decoding the common message. It is shown that our strategy achieves the symmetric capacity to within 1.14625 bits per channel use with duplexing factor 0.5, and 1.27125 bits per channel use for arbitrary duplexing factors, for all channel parameters. An important observation from the constant gap result is that strong interference can be beneficial with the presence of an OBR.
Superconducting Magnet System for the Spirit Cosmic Ray Space Telescope

The identity of the source of the cosmic radiation is one of the oldest and most interesting unanswered questions of 20th-century physics. While it has become increasingly clear that these energetic particles owe their existence to some of the most violent processes that occur in our galaxy (e.g., supernovae), a detailed understanding of the cosmic ray source and the conditions of galactic propagation has not been achieved. Of particular interest in this regard is the isotopic composition of the cosmic radiation since nuclear abundance anomalies would provide the most exciting clues as to their nuclear origin. The iron isotopes provide the most fruitful candidates for such a study since they are both abundant and are least modified by galactic transport. To date the most accurate isotopic studies of the iron group cosmic rays [1]have ruled out large deviations from solar system source composition. In order to achieve a convincing separation of the isotopes of iron it is necessary to design an instrument which can collect over 104 iron nuclei and achieve a mass resolution of σ ≲ 0.15 amu.
Gaugino condensation, loop corrections and S-duality constraint

Amongst the candidates for fundamental unified theories, heterotic superstring theory with gauge group E 8 × E 8 seems to be the most promising one. This is because the spectrum of the theory easily accomodates the Standard Model spectrum and gauge structure. In addition, the underlying gauge group contains an extra factor of E 8 which provides an ‘hidden sector’, which couples to the observable sector only through gravity, and, as will be discussed below, plays a crucial role in the mechanism of supersymmetry breaking. Furthermore, the effective theories that describe the heterotic string in 4 dimensions below the Planck scale are (nonrenormalizable) locally supersymmetric effective field theories. Indeed, requiring supersymmetry at energies well above M w in order to stabilize the gauge hierarchy, in some sense forces one to consider locally supersymmetric theories: A unified field theory must include gravity. Within the framework of General Relativity, a supersymmetric theory has to be locally supersymmetric. This follows from the fact that the supersymmetry transformation on the metric, or on the vielbein must include general coordinate transformations. Supergravity theories are nonrenormalizable, but can be consistently viewed as low-energy effective field theories (LEEFT) for the massless modes of superstring.
Self‐assembled fibrillar networks and molecular gels employing 12‐hydroxystearic acid and its isomers and derivatives

Self-assembly of small molecules can lead to many different types of objects and phases. This mini-review concentrates on the formation of one-dimensional objects and their transformation into gels from solutions/sols of 12-hydroxystearic acid, a molecule derived from the castor bean, and its derivatives in a wide variety of liquids. It is shown how the molecular packing within the one-dimensional objects and the nature of the derived gels can be correlated with systematic variations of the gelator structure and the type of liquid. Copyright © 2013 John Wiley & Sons, Ltd.
On Zero-Sum Optimal Stopping Games

On a filtered probability space \((\Omega ,\mathcal {F},P,\mathbb {F}=(\mathcal {F}_t)_{t=0,\ldots ,T})\), we consider stopping games \(\overline{V}:=\inf _{{\varvec{\rho }}\in \mathbb {T}^{ii}}\sup _{\tau \in \mathcal {T}}\mathbb {E}[U({\varvec{\rho }}(\tau ),\tau )]\) and \(\underline{V}:=\sup _{{\varvec{\tau }}\in \mathbb {T}^i}\inf _{\rho \in \mathcal {T}}\mathbb {E}[U(\rho ,{\varvec{\tau }}(\rho ))]\) in discrete time, where U(s, t) is \(\mathcal {F}_{s\vee t}\)-measurable instead of \(\mathcal {F}_{s\wedge t}\)-measurable as is assumed in the literature on Dynkin games, \(\mathcal {T}\) is the set of stopping times, and \(\mathbb {T}^i\) and \(\mathbb {T}^{ii}\) are sets of mappings from \(\mathcal {T}\) to \(\mathcal {T}\) satisfying certain non-anticipativity conditions. We will see in an example that there is no room for stopping strategies in classical Dynkin games unlike the new stopping game we are introducing. We convert the problems into an alternative Dynkin game, and show that \(\overline{V}=\underline{V}=V\), where V is the value of the Dynkin game. We also get optimal \({\varvec{\rho }}\in \mathbb {T}^{ii}\) and \({\varvec{\tau }}\in \mathbb {T}^i\) for \(\overline{V}\) and \(\underline{V}\) respectively.
Improvement of systems management policies using hybrid reinforcement learning

Reinforcement Learning (RL) holds particular promise in an emerging application domain of performance management of computing systems. In recent work, online RL yielded effective server allocation policies in a prototype Data Center, without explicit system models or built-in domain knowledge. This paper presents a substantially improved and more practical “hybrid” approach, in which RL trains offline on data collected while a queuing-theoretic policy controls the system. This approach avoids potentially poor performance in live online training. Additionally we use nonlinear function approximators instead of tabular value functions; this greatly improves scalability, and surprisingly, eliminated the need for exploratory actions. In experiments using both open-loop and closed-loop traffic as well as large switching delays, our results show significant performance improvement over state-of-art queuing model policies.
Wrap-Up: a trainable discourse module for information extraction

The vast amounts of on-line text now available have led to renewed interest in information extraction (IE) systems that analyze unrestricted text, producing a structured representation of selected information from the text. This paper presents a novel approach that uses machine learning to acquire knowledge for some of the higher level IE processing. Wrap-Up is a trainable IE discourse component that makes intersentential inferences and identifies logical relations among information extracted from the text. Previous corpus-based approaches were limited to lower level processing such as part-of-speech tagging, lexical disambiguation, and dictionary construction. Wrap-Up is fully trainable, and not only automatically decides what classifiers are needed, but even derives the feature set for each classifier automatically. Performance equals that of a partially trainable discourse module requiring manual customization for each domain.
Near Maximum-Likelihood Detector and Channel Estimator for Uplink Multiuser Massive MIMO Systems With One-Bit ADCs

In massive multiple-input multiple-output (MIMO) systems, it may not be power efficient to have a pair of high-resolution analog-to-digital converters (ADCs) for each antenna element. In this paper, a near maximum likelihood (nML) detector for uplink multiuser massive MIMO systems is proposed where each antenna is connected to a pair of one-bit ADCs, i.e., one for each real and imaginary component of the baseband signal. The exhaustive search over all the possible transmitted vectors required in the original maximum likelihood (ML) detection problem is relaxed to formulate an ML estimation problem. Then, the ML estimation problem is converted into a convex optimization problem which can be efficiently solved. Using the solution, the base station can perform simple symbol-by-symbol detection for the transmitted signals from multiple users. To further improve detection performance, we also develop a two-stage nML detector that exploits the structures of both the original ML and the proposed (one-stage) nML detectors. Numerical results show that the proposed nML detectors are efficient enough to simultaneously support multiple uplink users adopting higher-order constellations, e.g., 16 quadrature amplitude modulation. Since our detectors exploit the channel state information as part of the detection, an ML channel estimation technique with one-bit ADCs that shares the same structure with our proposed nML detector is also developed. The proposed detectors and channel estimator provide a complete low power solution for the uplink of a massive MIMO system.
Caregiving experiences predict changes in spiritual well-being among family caregivers of cancer patients.

Objective Although enhanced spiritual well-being has been linked to positive mental health outcomes among family caregivers of cancer patients, little is known regarding predictors of spiritual well-being in this population. The current study aimed to examine caregiving experiences as predictors of change in family caregivers' spiritual well-being during the initial months following the patient's cancer diagnosis. Methods Seventy family caregivers of newly diagnosed cancer patients (74% female, mean age = 59 years) participated in this longitudinal survey. Caregivers completed baseline questionnaires shortly before staying with the patient at an American Cancer Society Hope Lodge. Baseline questionnaires assessed caregiving experiences (i.e., self-esteem related to caregiving, family support for providing care, impact of caregiving on finances, and impact of caregiving on one's schedule). In addition, caregivers' spiritual well-being (i.e., meaning in life, peace, and faith) was assessed at baseline and 4-month follow-up. Results In univariate analyses, all caregiving experiences studied were associated with one or more aspects of spiritual well-being at 4-month follow-up. However, in the multivariate analysis, the only caregiving experience associated with aspects of spiritual well-being at 4-month follow-up was caregivers' perceptions of family support. Specifically, lack of family support was associated with lower levels of meaning and peace. Conclusions Findings point to the importance of family support in facilitating the search for meaning and peace shortly after a loved one's cancer diagnosis and suggest that interventions targeting caregivers' support system may enhance their spiritual well-being. Copyright © 2014 John Wiley & Sons, Ltd.
Estimating poverty in the absence of consumption data : the case of Liberia

In much of the developing world, the demand for high frequency quality household data for poverty monitoring and program design far outstrips the capacity of the statistics bureau to provide such data. In these environments, all available data sources must be leveraged. Most surveys, however, do not collect the detailed consumption data necessary to construct aggregates and poverty lines to measure poverty directly. This paper benefits from a shared listing exercise for two large-scale national household surveys conducted in Liberia in 2007 to explore alternative methodologies to estimate poverty indirectly. The first is an asset-based model that is commonly used in Demographic and Health Surveys. The second is a survey-to-survey imputation that makes use of small area estimation techniques. In addition to a standard base model, separate models are estimated for urban and rural areas and an expanded model that includes climatic variables. Special attention is paid to the inclusion of cell phones, with implications for other assets whose cost and availability may be changing rapidly. The results demonstrate substantial limitations with asset-based indexes, but also leave questions as to the accuracy and stability of imputation models.
Hospital Acquisition of Physician Groups: On the Road to Value-Based or Higher-Priced Care?

An important goal of the Affordable Care Act is to transform the US health care system from one characterized by high costs, poor quality, and fragmented care to one focused on comprehensive, coordinated, and efficient care.
Alcohols as alkylating agents in heteroarene C-H functionalization

The biochemical process of spin-centre shift is used to accomplish mild, non-traditional alkylation reactions using alcohols as radical precursors; this represents the first broadly applicable use of unactivated alcohols as latent alkylating reagents, achieved via the successful merger of photoredox and hydrogen atom transfer catalysis. A central reaction in DNA biosynthesis is ribonucleotide deoxygenation via the radical-mediated elimination of H2O, which is an example of 'spin-centre shift' (SCS), during which an alcohol C–O bond is cleaved to produce in a carbon-centred radical intermediate. Although SCS is a well-understood biochemical process, it is underutilized by the synthetic organic chemistry community. Here Jian Jin and David MacMillan show that it is possible to take advantage of this naturally occurring process to accomplish mild, non-traditional alkylations using alcohols as radical precursors. This method represents the first broadly applicable use of unactivated alcohols as latent alkylating reagents, achieved via the merger of photoredox and hydrogen atom transfer catalysis. Redox processes and radical intermediates are found in many biochemical processes, including deoxyribonucleotide synthesis and oxidative DNA damage1. One of the core principles underlying DNA biosynthesis is the radical-mediated elimination of H2O to deoxygenate ribonucleotides, an example of ‘spin-centre shift’2, during which an alcohol C–O bond is cleaved, resulting in a carbon-centred radical intermediate. Although spin-centre shift is a well-understood biochemical process, it is underused by the synthetic organic chemistry community. We wondered whether it would be possible to take advantage of this naturally occurring process to accomplish mild, non-traditional alkylation reactions using alcohols as radical precursors. Because conventional radical-based alkylation methods require the use of stoichiometric oxidants, increased temperatures or peroxides3,4,5,6,7, a mild protocol using simple and abundant alkylating agents would have considerable use in the synthesis of diversely functionalized pharmacophores. Here we describe the development of a dual catalytic alkylation of heteroarenes, using alcohols as mild alkylating reagents. This method represents the first, to our knowledge, broadly applicable use of unactivated alcohols as latent alkylating reagents, achieved via the successful merger of photoredox and hydrogen atom transfer catalysis. The value of this multi-catalytic protocol has been demonstrated through the late-stage functionalization of the medicinal agents, fasudil and milrinone.
Isospin transfer modes in exotic nuclei

This work presents an approach to nuclear spin-isospin response, which is capable of describing the overall strength distribution up to high excitation energies, including the fine structure of the low-lying strength, and resolving the long-standing quenching problem. The model is a covariant realization of the nuclear field theory and based on the self-consistent extensions of the covariant energy density functional (CEDF) theory. Results of the recent calculations for spin-isospin response of ordinary and exotic medium-mass nuclei are presented and discussed.
Experiments on initial and boundary conditions

Experimentalists have learnt to appreciate the importance of a proper installation, a careful calibration of instruments, and an analysis of environmental interferences. Data obtained by the Wright brothers in their historic wind tunnel enabled them to evaluate the possibility of flying; by current standards they would probably not even fit in what engineers call the “ballpark” range. The designer’s problem is efficiency; errors larger than 1% in basic information should not be tolerated.
Grameen bank lending : does group liability matter ?

Competing theories increasingly support the positive role of social capital in small loan default costs of group lending; at the same time, potential group collusion may increase loan delinquencies. Findings from the available literature are mixed on the role of the various attributes of group lending. But past studies suffer from estimation bias due to the unobserved sorting behavior of group members and their other attributes. This paper attempts to resolve that estimation bias by utilizing longitudinal data from 297 Grameen Bank groups since their inceptions. A dynamic lagged dependent model with correction for time-varying heterogeneity of group and individual behavior is applied to estimate the effect of group liability in the Grameen Bank. The results suggest that group liability matters in both loan disbursement and repayment, with women less of a credit risk than men and women's groups more homogeneous than men's. Finally, the benefits of social capital outweigh the costs of group collusion, especially for women's groups, thereby reducing overall default rates. The risk-pooling behavior of diverse men's groups increases men's repayment behavior. Overall, group lending as practiced by Grameen Bank appears to increase repayment rates.
Finite-temperature mechanical instability in disordered lattices

Mechanical instability takes different forms in various ordered and disordered systems and little is known about how thermal fluctuations affect different classes of mechanical instabilities. We develop an analytic theory involving renormalization of rigidity and coherent potential approximation that can be used to understand finite-temperature mechanical stabilities in various disordered systems. We use this theory to study two disordered lattices: a randomly diluted triangular lattice and a randomly braced square lattice. These two lattices belong to two different universality classes as they approach mechanical instability at T=0. We show that thermal fluctuations stabilize both lattices. In particular, the triangular lattice displays a critical regime in which the shear modulus scales as G∼T(1/2), whereas the square lattice shows G∼T(2/3). We discuss generic scaling laws for finite-T mechanical instabilities and relate them to experimental systems.
ECA: High Dimensional Elliptical Component Analysis in non-Gaussian Distributions

ABSTRACTWe present a robust alternative to principal component analysis (PCA)—called elliptical component analysis (ECA)—for analyzing high-dimensional, elliptically distributed data. ECA estimates the eigenspace of the covariance matrix of the elliptical data. To cope with heavy-tailed elliptical distributions, a multivariate rank statistic is exploited. At the model-level, we consider two settings: either that the leading eigenvectors of the covariance matrix are nonsparse or that they are sparse. Methodologically, we propose ECA procedures for both nonsparse and sparse settings. Theoretically, we provide both nonasymptotic and asymptotic analyses quantifying the theoretical performances of ECA. In the nonsparse setting, we show that ECA’s performance is highly related to the effective rank of the covariance matrix. In the sparse setting, the results are twofold: (i) we show that the sparse ECA estimator based on a combinatoric program attains the optimal rate of convergence; (ii) based on some recent d...
Can subjective questions on economic welfare be trusted ? evidence for three developing countries

While self-assessments of welfare have become popular for measuring poverty and estimating welfare effects, the methods can be deceptive given systematic heterogeneity in respondents' scales. Little is known about this problem. This study uses specially-designed surveys in three countries, Tajikistan, Guatemala, and Tanzania, to study scale heterogeneity. Respondents were asked to score stylized vignettes, as well as their own household. Diverse scales are in evidence, casting considerable doubt on the meaning of widely-used summary measures such as subjective poverty rates. Nonetheless, under the identifying assumptions of the study, only small biases are induced in the coefficients on widely-used regressors for subjective poverty and welfare.
Galaxies with Spiral Structure up to z 0.87: Limits on M/L and the Stellar Velocity Dispersion

We consider seven distant galaxies with clearly evident spiral structure from Hubble Space Telescope images. We place upper limits on their mass-to-light ratios (M/L) by computing M/LB for a maximal disk. We find that these galaxies have maximal-disk mass-to-light ratios M/LB = 1.5–3.5 (M/LB)⊙ at the low end, but within the range seen in nearby galaxies. The mass-to-light ratios are low enough to suggest that the galaxies contain a young, rapidly formed stellar population. By using a Toomre stability criterion for formation of spiral structure, we place constraints on the ratio of M/L to the stellar velocity dispersion. If these galaxies have maximal disks, they would have to be nearly unstable so as to have small enough velocity dispersions that their disks are not unrealistically thick. This suggests that either a fraction of the light originates from a component of stars in a thick disk or bulge not strongly affected by the spiral structure, or there is a substantial amount of dark matter present in the luminous regions of the galaxy.
Biosynthesis via carbocations: Theoretical studies on terpene formation

Covering: up to the end of 2010 This review describes applications of quantum chemical calculations in the field of terpene biosynthesis, with a focus on insights into the mechanisms of terpene-forming carbocation rearrangements arising from theoretical studies.
Fiber-optic tunable microwave transversal filter

Existing adaptive signal processors are typically implemented by using digital circuits and techniques and so are limited to 1 GHz or less. Fiber-optic signal processing, capable of much higher frequencies, has seen recent rapid development. Transversal filters are reconfigured by weight and/or time-delay control and typically require a plurality of control signals to set the weight or time delay of each signal to be summed. Here we demonstrate the performance of a novel tunable fiber-optic finite-impulse-response (FIR) filter with continuously variable unit time delays (Fig. 1). The FIR filter utilizes several taps with varying net chromatic dispersion (a fiber-optic prism) and an externally modulated wavelength-tunable source.1
Evolution of the clinical review station for enterprise-wide multimedia radiology reporting

Efforts to develop Picture Archiving and Communications Systems (PACS) for the last ten years have concentrated mainly on developing systems for primary interpretation of digital radiological images. Much less attention has been paid to the clinical aspects of the radiology process. Clinical radiology services are an important component of the overall care delivery process, providing information and consultation services to referring physicians, the customers of radiology, in a timely fashion to aid in care decisions. Information management systems (IMS) are playing an increasingly central role in the care delivery process. No suitable commercial PACS or IMS products were available that could effectively provide for the requirements of the clinicians. We endeavored to fill this void at our institution by developing a system to deliver images and text reports electronically on-demand to the referring physicians. This system has evolved substantially since initial deployment eight years ago. As new technologies become available they are evaluated and integrated as appropriate to improve system performance and manageability. Not surprisingly, the internet and World Wide Web (WWW) technology has had the greatest impact on system design in recent years. Additional features have been added over time to provide services for teleradiology, teaching, and research needs. We also discovered that these value-added services give us a competitive edge in attracting new business to our department. Commercial web-based products are now becoming available which do a satisfactory job of providing many of these clinical services. These products are evaluated for integration into our system as they mature. The result is a system that impacts positively on patient care.
Engendering a Clinic: Lessons Learned from a Domestic Violence Clinical Course in Qatar

Domestic violence, a serious problem around the world, remains a hidden concern among the Islamic Gulf States. Yet signs indicate the situation is changing. A team of American lawyers and professors, responding to student initiative and the Qatari development strategy, recently initiated Qatar's first law school clinic, focusing exclusively on domestic violence. By highlighting the students' experience, this article outlines the issues involved and the problems that were encountered, and resolved, during the development of this clinic. The students first studied the issue of domestic violence, then made presentations to the larger community to raise awareness of the topic. Subsequent to a review of international law, the Qatari criminal code and model domestic violence statutes from other jurisdictions, the students drafted legislation designed to criminalize domestic violence in Qatar. Finally, they developed what they called An Action Plan to Stop Domestic Violence in Qatar. This article also explores how the clinic's work was informed by the sex-segregated educational environment, by Islamic culture at large, and by feminist and traditional interpretations of the Qur'an. The authors offer reflections on the lessons they learned and propose suggestions about how such pedagogy might proceed in future. KEYWORDS: domestic violence, gender relations, clinical legal education, Qatari legal and educational systems, Islamic interpretation Language: en
Asymmetric copper(I)-catalyzed Henry reaction with an aminoindanol-derived bisoxazolidine ligand.

Bisoxazolidine 1 is an effective ligand in the Me2Zn-promoted and the Cu(I)-catalyzed Henry reaction. While a wide range of nitroaldol products are obtained in high yields and ee’s in both cases, the replacement of dimethylzinc with copper(I) acetate results in a complete reversal of the sense of asymmetric induction. The Cu(I)-catalyzed enantioselective addition of nitromethane to methyl 4-oxobutanoate followed by hydrogenation and spontaneous lactamization gives (S)-5-hydroxypiperidin-2-one in 72% overall yield and 98% ee which compares favorably with previously reported methods.
ARMA parameter estimation using only output cumulants

Several algorithms are developed to estimate the parameters of a causal nonminimum-phase autoregressive moving average (ARMA) (p,q) system which is excited by an unobservable independently identically distributed non-Gaussian process. The output is contaminated by additive colored Gaussian noise of unknown power spectral density. A fundamental result is presented pertaining to the identifiability of AR parameters, based on the Yule-Walker equations drawn from a (specific) set of (p+1) 1-D slices of the kth (k>2) order output cumulant. Several MA parameter estimation algorithms are developed: one method uses q 1-D slices of the output cumulant; a second method uses only two 1-D cumulant slices. These methods do not involve computation of the residual (i.e. AR compensated) time series or polynomial factorization. Multidimensional versions of the various algorithms are presented. A simulation study demonstrating the effectiveness of the algorithms is included. >
The Kagomé-staircase lattice: magnetic ordering in Ni3V2O8 and CO3V2O8

Abstract Ni3V2O8 and Co3V2O8 have spin-1 and spin- 3 /2 magnetic lattices that are a new anisotropic variant of the Kagome net, wherein edge-sharing MO6 octahedra form the rises and rungs of a ‘Kagome staircase’. The anisotropy largely relieves the geometric frustration, but results in rich magnetic behavior. Characterization of the magnetization of polycrystalline samples reveals that the compounds are ferrimagnetic in character. Heat capacity measurements show the presence of four magnetic phase transitions below 9 K for Ni3V2O8 and two below 11 K for Co3V2O8. Comparison to the low temperature heat capacity of isostructural nonmagnetic Zn3V2O8 provides an estimate of the magnetic entropy involved with the phase transitions. The results suggest that Co3V2O8 may display magnetic transitions below 2 K.
Quantized compute and forward: A low-complexity architecture for distributed antenna systems

We consider a low-complexity version of the Compute and Forward scheme that involves only scaling, offset (dithering removal) and scalar quantization at the relays. The proposed scheme is suited for the uplink of a distributed antenna system where the antenna elements must be very simple and are connected to a joint processor via orthogonal perfect links of given rate R 0 . We consider the design of non-binary LDPC codes naturally matched to the proposed scheme. Each antenna element performs individual (decentralized) Belief Propagation decoding of its own quantized signal, and sends a linear combination of the users' information messages via the noiseless link to the joint processor, which retrieves the users' messages by Gaussian elimination. The complexity of this scheme is linear in the coding block length and polynomial in the system size (number of relays).
Highly selective supramolecular catalyzed allylic alcohol isomerization.

A supramolecular tetrahedral assembly Na12[Ga4L6] (L = 1,5-bis-catecholamide naphthalene) has been found to selectively encapsulate monocationic rhodium complexes of the appropriate size and shape. Encapsulation within the chiral environment of the host directly affects the symmetry of the rhodium guest and can be well characterized by NMR spectroscopy. The rhodium complexes were found to be catalytically active for the isomerization of allylic alcohols. Investigations into the catalytic activity of the encapsulated rhodium guests have shown that the constrained cavity of the host exerts a strong influence on the reactivity at the metal center. The supramolecular host prevents substrates of the wrong size and shape from entering the host cavity and reacting with the encapsulated metal center, while substrates of the correct dimensions are allowed ready access. These results suggest that the metal center remains in the active site of the host while reactants and products freely and rapidly access the host ...
Thermoelectric properties of the incommensurate layered semiconductor GexNbTe2

The compounds GexNbTe2 (0.39 ≤ x ≤ 0.53) have been studied for their thermoelectric properties. By changing x, the carrier concentration can be adjusted so that the material changes from a p-type metal to a p-type semiconductor. The maximum germanium concentration at about Ge0.5NbTe2 is also the most semiconducting composition. High- and low-temperature electrical resistivity, Hall effect, Seebeck coefficient, and thermal conductivity were measured. Evidence of electronic ordering was found in some samples. The thermal conductivity is reasonably low and glasslike with room temperature values around 20–25 mW/cm K. However, the power factor is too low to compete with state-of-the-art materials. The maximum thermoelectric figure of merit, ZT found in these compounds is about 0.12. The low ZT can be traced to the low carrier mobility of about 10 cm2 /Vs. The related compounds Si0.5NbTe2 and Ge0.5TaTe2 were also studied.
Oxygen and I

Abstract Oxygen is a remarkable element and without it in its triplet, more stable state, complex life on earth would not be possible. The singlet carbon-hydrogen bond does not react readily with oxygen because of the spin barrier. Nature has, however, solved this problem by using iron based enzymes either of the heme-type (porphyrin ligand) or of the non-heme type. The P 450 enzymes are illustrative of the first kind. Methane monooxygenase (MMO) is a good example of the second type. Recent work on the selective functionalization of saturated hydrocarbons has provided a system which, like MMO, has a μ-oxo-di-iron center with obligatory carboxylate complexation. In this system, two manifolds, Fe II Fe IV and Fe III Fe V provide two different processes for the selective conversion of saturated hydrocarbons into ketones.
On the sum of k largest singular values of graphs and matrices

In the recent years, the trace norm of graphs has been extensively studied under the name of graph energy. The trace norm is just one of the Ky Fan k-norms, given by the sum of the k largest singular values, which are studied more generally in the present paper. Several relations to chromatic number, spectral radius, spread, and to other fundamental parameters are outlined. Some results are extended to more general matrices.
Properties and morphology of barium germanate glasses

The density, thermal expansion behavior, and transformationrange viscosity of barium germanate glasses containing 0 to 9 mol% BaO were measured. The addition of BaO to GeO/sub 2/ resulted in phase separation at all BaO concentrations. The results of the property measurements indicate that glasses containing up to 3 mol% BaO consist of a matrix of essentially pure GeO/sub 2/ with barium-rich droplets. Glasses containing 6 mol% BaO or more consist of two interconnected vitreous phases. The morphology of glasses containing between approximately 3.5 and 5.5 mol% BaO can be altered from the droplet/matrix form to that of two continuous phases by the appropriate heat treatment.
Stereocontrolled Second Generation Syntheses of the ABC and FG Ring Systems of Brevetoxin B

Abstract Stereocontrolled, second generation syntheses of the ABC and FG ring systems of brevetoxin B (1) are described. The two key intermediates 2 and 3 , representing the ABC and FG ring frameworks, were prepared from 2-deoxy-D-ribose via short and efficient sequences. The synthesis of 2 proceeded via the epoxy alcohol cyclization precursors 6 and 7 , and the Horner-Emmons cyclization precursor 5 , to give the desired tricyclic system in 3.6% overall yield. The synthesis of 3 proceeded via the epoxy alcohol cyclization precursors 10 and 11 to give the desired bicyclic system in a 11.5% overall yield. Both syntheses represent improvements over the previous procedures and allow for rapid and facile entries into the ABC and FG ring systems of this complex natural product.
Estimation of the Lunar Physical Librations

The recent long-term integration of JPL ephemeris DE403/LE403 yielded lunar physical librations covering 6000 years. A Fourier analysis of a 718-year subset of this span produced estimates of the component frequencies of the forced and free librations. A subsequent iterative least-squares estimation procedure provided precise values for phases and for time-varying amplitudes and frequencies. Two free libration modes were found; presence of a third is possible but close to the noise.
Evaluating the utility of anonymized network traces for intrusion detection

To intelligently create policies governing the anonymization of network logs, one must analyze the effects of anonymization on both the security and utility of sanitized data. In this paper, we focus on analyzing the utility of network traces post-anonymization. Any measure of utility is subjective to the type of analysis being performed. This work focuses on utility for the task of attack detection since attack detection is an important part of an incident responders daily responsibilities. We employ a methodology we developed that analyzes the effect of anonymization on Intrusion Detection Systems (IDS), and we provide the first rigorous analysis of single field anonymization on IDS effectiveness. Through this work we can begin to answer the questions of whether the field affects anonymization more than the algorithm; which fields have a larger impact on utility; and which anonymization algorithms have a larger impact on utility.
Bifunctional Asymmetric Catalysis: A Tandem Nucleophile/Lewis Acid Promoted Synthesis of β-Lactams

We describe a superior procedure for the catalytic, asymmetric synthesis of β-lactams using a bifunctional catalyst system consisting of a chiral nucleophile and an achiral Lewis acid.
The entropy in groups – a clue to galaxy formation

Abstract The entropy in the hot X-ray gas in groups of galaxies is a fossil of the process of galaxy formation The amount of entropy in these low mass systems considerably exceeds that predicted from structure formation models. To explain these results requires “extra” energy which is a relic of the process of star formation and active galaxy heating. We present new XMM results on the entropy and entropy profiles. These results are inconsistent with pre-heating scenarios which have been developed to explain the entropy floor in groups but are broadly consistent with models of structure formation which include the effects of heating and/or the cooling of the gas. The total entropy in these systems provides a strong constraint on all models of galaxy and group formation, and on the poorly defined feedback process which controls the transformation of gas into stars and thus the formation of structure in the universe.
Fabrication and characterization of amorphous lithium electrolyte thin films and rechargeable thin-film batteries

Amorphous oxide and oxynitride lithium electrolyte thin films were synthesized by r.f. magnetron sputtering of lithium silicates and lithium phosphates in Ar, Ar + O2, Ar + N2, or N2. The composition, structure, and electrical properties of the films were characterized using ion and electron beam, X-ray, optical, photoelectron, and a.c. impedance techniques. For the lithium phosphosilicate films, lithium ion conductivities as high as 1.4 × 10−6 S/cm at 25 °C were observed, but none of these films selected for extended testing were stable in contact with lithium. On the other hand, a new thin-film lithium phosphorus oxynitride electrolyte, synthesized by sputtering Li3PO4 in pure N2, was found to have a conductivity of 2 × 10-6 S/cm at 25 °C and excellent long-term stability in contact with lithium. Thin-films cells consisting of a 1 μm thick amorphous V2O5 cathode, a 1 μm thick oxynitride electrolyte film, and a 5 μm thick lithium anode were cycled between 3.7 and 1.5 V using discharge rates of up to 100 μA/cm2 and charge rates of up to 20 μA/cm2. The open-circuit voltage of 3.6 to 3.7 V of fully-charged cells remained virtually unchanged after months of storage.
A Simple Estimator for Binary Choice Models with Endogenous Regressors

This paper provides a few variants of a simple estimator for binary choice models with endogenous or mismeasured regressors, or with heteroskedastic errors, or with panel fixed effects. Unlike control function methods, which are generally only valid when endogenous regressors are continuous, the estimators proposed here can be used with limited, censored, continuous, or discrete endogenous regressors, and they allow for latent errors having heteroskedasticity of unknown form, including random coefficients. The variants of special regressor based estimators we provide are numerically trivial to implement. We illustrate these methods with an empirical application estimating migration probabilities within the US.
N = 1 dualities of SO and USp gauge theories and T-duality of string theory

Abstract Extending recent work on SO gauge theory, we engineer local string models for N = 1 four-dimensional SO and USp gauge theories coupled to matter in the fundamental. The local models are type IIB orientifolds with D7 branes on a curved orientifold 7-plane, and matter realized by adding D3 branes on the orientifold plane. The Higgs branches of the SO and USp theories can be matched with the moduli spaces of SO and USp instantons on the compact four-dimensional part of the D7 branes world-volume. The R -charge of the gauge theories is identified with a U (1) symmetry on the world-volume of an Euclidean D3 brane instanton. We argue that the quantum field theory dualities of these gauge theories arise from T -dualities of type IIB strings exchanging D7 and D3 charges. A crucial role is played by the induced D3 charge of D7 branes and an orientifold 7-plane, both partially compactified on a Z 2 orbifold of K 3.
Almost-bipartite distance-regular graphs with the Q-polynomial property

Let Γ denote a Q-polynomial distance-regular graph with diameter D ≥ 4. Assume that the intersection numbers of Γ satisfy ai = 0 for 0 ≤ i ≤ D - 1 and aD ≠ 0. We show that Γ is a polygon, a folded cube, or an Odd graph.
PUBLIC HEALTH LAW: POWER, DUTY, RESTRAINT

(2001). PUBLIC HEALTH LAW: POWER, DUTY, RESTRAINT. Journal of Legal Medicine: Vol. 22, No. 4, pp. 581-588.
BLACK HOLE SPIN AND THE RADIO LOUD/QUIET DICHOTOMY OF ACTIVE GALACTIC NUCLEI

Radio loud active galactic nuclei (AGNs) are on average 1000 times brighter in the radio band compared to radio quiet AGNs. We investigate whether this radio loud/quiet dichotomy can be due to differences in the spin of the central black holes (BHs) that power the radio-emitting jets. Using general relativistic magnetohydrodynamic simulations, we construct steady state axisymmetric numerical models for a wide range of BH spins (dimensionless spin parameter 0.1 <= a <= 0.9999) and a variety of jet geometries. We assume that the total magnetic flux through the BH horizon at radius r{sub H}(a) is held constant. If the BH is surrounded by a thin accretion disk, we find that the total BH power output depends approximately quadratically on the angular frequency of the hole, P {proportional_to} OMEGA{sup 2}{sub H} {proportional_to} (a/r{sub H}){sup 2}. We conclude that, in this scenario, differences in the BH spin can produce power variations of only a few tens at most. However, if the disk is thick such that the jet subtends a narrow solid angle around the polar axis, then the power dependence becomes much steeper, P {proportional_to} OMEGA{sup 4}{sub H} or even {proportional_to}OMEGA{sup 6}{sub H}. Power variations of 1000 are then possiblemore » for realistic BH spin distributions. We derive an analytic solution that accurately reproduces the steeper scaling of jet power with OMEGA{sub H} and we provide a numerical fitting formula that reproduces all our simulation results. We discuss other physical effects that might contribute to the observed radio loud/quiet dichotomy of AGNs.« less
Combustion control using a multiplexed diode-laser sensor system

A multiplexed diode-laser sensor system, comprised of two InGaAsP diode lasers and fiber-optic components, has been developed to nonintrusively measure temperature and species concentration over a single path for closed-loop process control using laser absorption spectroscopy techniques. The system was applied to measure and control the gas temperature in the postflame gases 6 mm above the surface of a Hencken burner (for multiple CH 4 -air diffusion flames). The wavelengths of the lasers were independently current tuned across H 2 O transitions near 1343 nm ( ν 1 + ν 3 band) and 1392 nm (2 ν 1 , ν 1 + ν 3 bands). Temperature was determined from the ratio of measured peak absorption coefficients. H 2 O concentration was determined from the measured absorption coefficient of one transition set at the measured temperature. The mean temperatures recorded compared well with those measured by a thermocouple. Temperature fluctuations up to 250 Hz were measured accurately with the sensor system, demonstrating the high bandwidth of the measurement technique. A computer-controlled, closed-loop feedback circuit controlled the flame temperature in the probed region by adjusting the fuel flow in response to the difference between the measured and the desired gas temperature. The results obtained with this first-generation system demonstrate the potential of multiplexed diode lasers for rapid, continuous, nonintrusive, in situ measurements and control of combustion environments.
Optical fiber modal noise in the 0.8 to 1.5 micron region and implications for near infrared precision radial velocity measurements

Modal noise in fibers has been shown to limit the signal-to-noise ratio achievable in fiber-coupled, high-resolution spectrographs if it is not mitigated via modal scrambling techniques. Modal noise become significantly more important as the wavelength increases and presents a risk to the new generation of near-infrared precision radial spectrographs under construction or being proposed to search for planets around cool M-dwarf stars, which emit most of their light in the NIR. We present experimental results of tests at Penn State University characterizing modal noise in the far visible out to 1.5 microns and the degree of modal scrambling we obtained using mechanical scramblers. These efforts are part of a risk mitigation effort for the Habitable Zone Planet Finder spectrograph currently under development at Penn State University.