cssi/SciSciGPT-SciSciNet huggingface dataset:
The twilight of hierarchy: speculations on the global information society

The paper examines the consequences of the "informatization" of society, a term originated in France which describes what is happening to some of our key concepts and conceptions as the convergence of computers and telecommunications makes information the dominant resource in post–industrial society. The inherent characteristics of information provide some clues as to what that portends for the future. Information is expandable, is not resource–hungry, is substitutable, transportable, diffusive and can be shared. We will make trouble for ourselves by carrying over into our thinking about information, concepts developed for the management of things (property, depletion, depreciation, monopoly, unfairnesses in distribution, geopolitics, the class struggle and top–down leadership). Because we can no longer rely on old assumptions, the new information environment is likely to modify our inherited thinking about rule, power, and authority. In the past the inherent characteristics of physical resources made possible the development of hierarchies of power based on control, hierarchies of influence based on secrecy, hierarchies of class based on ownership, of privilege based on early access to valuable resources and of politics based on geography. These five bases for discrimination and unfairness are crumbling today and will force changes in some long–standing hierarchical forms of social organization. Information technologies will be assimilated without turmoil only if scholars recognize the need to rethink their disciplines in light of the erosion of societies based on material resources and industrial production, if citizens get used to the responsibility that goes with the influence and power almost casually available to them through access to information, and if generalist leaders are able to rethink the nature of leadership.
Compactified Jacobians and q,t-Catalan numbers, I

J. Piontkowski described the homology of the Jacobi factor of a plane curve singularity with one Puiseux pair. We discuss the combinatorial structure of his answer, in particular, relate it to the bigraded deformation of Catalan numbers introduced by A. Garsia and M. Haiman.
Enantioselective Synthesis of 2-Arylbicyclo[1.1.0]butane Carboxylates

The rhodium-catalyzed reaction of 2-diazo-5-arylpent-4-enoates can be controlled by the appropriate choice of catalyst and catalyst loading to form either 2-arylbicyclo[1.1.0]butane carboxylates or cyclohexene derivatives. Both products are produced in a highly diastereoselective manner, with 2-arylbicyclo[1.1.0]butane carboxylates preferentially formed under low catalyst loadings. When the reaction is catalyzed by Rh2(R-BTPCP)4, the 2-arylbicyclo[1.1.0]butane carboxylates are generated with high levels of asymmetric induction (70–94% ee).
The Twentieth International Mathematical Olympiad

Andrew Bernoff Daniel Bloch Randall Dougherty Mark Kleiman Victor Milenkovic David Montana Ehud Reiter Charles Walter Upper Dublin High School Bellport High School W. T. Woodson High School Stuyvesant High School New Trier East High School Lawrenceville School T.S. Woo tton High School Centennial High School Fort Washington, Pa. Brookhaven, N.Y. Fairfax, Va. New York City, N.Y. Winnetka, 111. Lawrenceville, N.J. Rockville, Md. Champaign, 111.
Stress Strain Isotherms for Poly-(Dimethylsiloxane) Networks

Stress—strain isotherms are presented for poly‐(dimethylsiloxane) networks of different degrees of cross linking, swollen to various extents by a diluent. Results are interpreted in terms of the equation f*v213V*/(α−α−2)=2C1+2C2α−1, where f* is the tension per unit initial area (unswollen) exhibited by a network when swollen to a polymer volume fraction v2 and elongated to the relative length α, 2C1 is a parameter of the network structure established by the molecular theory of rubber elasticity, and 2C2 is an additional parameter found to give a better representation of experimental data. Values of C2 obtained for networks are found to decrease as the degree of cross linking is decreased, and the degree of swelling is increased.
The first Cu(I)-mediated nucleophilic trifluoromethylation reactions using (trifluoromethyl)trimethylsilane in ionic liquids

The new ionic liquids (5a–8a) were used as reaction media for nucleophilic trifluoromethylation reactions of trifluoromethyl(trimethyl)silane with (1) aryl, allyl, benzyl, and alkyl halides in Cu(I)-mediated C–C bond formation reactions, and (2) carbonyl functionalities catalyzed with Ph3P or CsF. In addition, conversion of benzyl bromide as a model compound to benzyl fluoride was examined in 6a using CsF as the fluorinating reagent. The morpholinium-based ionic liquid (6a) stood out as an efficient solvent system comparable to organic solvents and superior to the other new ionic liquids prepared in this work as well as to [bmim]+[PF6]−. Neat reactions of N-methyloxazolidine (1), N-methylmorpholine (2), N-methylimidazole (3) or N-methyltriazole (4) with 2-(2-ethoxyethoxy)ethyl bromide (BrCH2CH2OCH2CH2OCH2CH3, 9) or 2-bromoethyl methyl ether (BrCH2CH2OCH3, 10) at 75 or 105 °C gave the N-(2-ethoxyethoxy)ethyl- or N-methoxyethyl-substituted oxazolidinium, morpholinium, imidazolium and triazolium quaternary bromides (1a–4a, 1b–4b) which were metathesized with LiN(SO2CF3)2 to form the respective room-temperature liquid bis(trifluoromethanesulfonyl)amides 5a–8a and 5b–8b in high yields with transition or melting points 310 °C as determined by thermogravimetric analyses (TGA). Densities range between 1.29 and 1.53 g cm−3 at 25 °C.
Regioselective Synthesis of 2H-Indazoles Using a Mild, One-Pot Condensation–Cadogan Reductive Cyclization

An operationally simple and efficient one-pot synthesis of 2H-indazoles from commercially available reagents is reported. Ortho-imino-nitrobenzene substrates, generated via condensation, undergo reductive cyclization promoted by tri-n-butylphosophine to afford substituted 2H-indazoles under mild reaction conditions. A variety of electronically diverse ortho-nitrobenzaldehydes and anilines were examined. To further extend the scope of the transformation, aliphatic amines were also employed to form N2-alkyl indazoles selectively under the optimized reaction conditions.
Conjugated amplifying polymers for optical sensing applications.

Thanks to their unique optical and electrochemical properties, conjugated polymers have attracted considerable attention over the last two decades and resulted in numerous technological innovations. In particular, their implementation in sensing schemes and devices was widely investigated and produced a multitude of sensory systems and transduction mechanisms. Conjugated polymers possess numerous attractive features that make them particularly suitable for a broad variety of sensing tasks. They display sensory signal amplification (compared to their small-molecule counterparts) and their structures can easily be tailored to adjust solubility, absorption/emission wavelengths, energy offsets for excited state electron transfer, and/or for use in solution or in the solid state. This versatility has made conjugated polymers a fluorescence sensory platform of choice in the recent years. In this review, we highlight a variety of conjugated polymer-based sensory mechanisms together with selected examples from th...
Investment‐Based Corporate Bond Pricing

A standard assumption of structural models of default is that firms' assets evolve exogenously. In this paper, we examine the importance of accounting for investment options in models of credit risk. In the presence of financing and investment frictions, firm-level variables that proxy for asset composition are significant determinants of credit spreads beyond leverage and asset volatility, because they capture the systematic risk of firms' assets. Cross-sectional studies of credit spreads that fail to control for the interdependence of leverage and investment decisions are unlikely to be very informative. Such frictions also give rise to a realistic term structure of credit spreads in a production economy.
Pullorum Disease in the Mature Turkey

Abstract The presence of Pullorum Disease among avian species other than chickens has been noted by a few investigators. Although the principal host of the organism has been found to be the chicken, other avian species may play an important part in its dissemination. Hewitt1 reports on the isolation of Bact. pullorum from baby turkeys. He examined two small turkeys which had been hatched in an incubator used previously for hatching chicks. Gross lesions were not seen upon autopsy. Bact. pullorum was recovered from the heart blood and liver of the poults. The organism was of the aerogenic type attacking dextrose, mannite and galactose. Lactose, sucrose, maltose, dextrin and dulcite broth were not changed. The organism was found to be of low virulence when tested on rabbits, guinea pigs and chickens. Although the source of the infection was not determined the incubator was suspected. Hendrickson2 isolated Bact. pullorum from poults. The . . .
Another Look at Blow-Out Fractures of the Orbit

Thirty cases of orbital floor blow-out fractures proven by tomography were retrospectively reviewed to determine the accuracy of the plain films. Using the maximum diameter from the tomograms, the area and volume of the fractures were calculated and correlated with the presence of diplopia and enophthalmos at the time of presentation and at subsequent follow-up. Nine of the 30 cases underwent surgical repair. Orbital floor fractures were recognized in 29 of 30 cases using only the 28° Caldwell and Waters views. Routine tomography is unnecessary and should be reserved as a preoperative evaluation in patients with enophthalmos to establish the presence of a significant associated medial wall prolapse.
La producción de géneros específicos en contextos condicionados

Uno de los efectos mas notables del feminismo es que nos ha obligado a examinar la conducta social del hombre hacia la mujer. Lo que antes del movimiento feminista o no se cuestionaba o se explicaba y justificaba como simple inercia de costumbres centenarias, ahora se escudrina, se sanciona, se pone en tela de juicio, se acusa. Hasta el piropo -forma milenaria pero unilateral de expresar admiracion por los atributos femeninos- se ha venido atacando como instrumento de agresion masculina para dominar a la mujer. En los momentos mas algidos de la confrontacion machismo~feminismo, no han faltado mujeres que les hayan silbado a los hombres en signo de falsa admiracion; y hasta hubo mujeres que, para dramatizar la humillacion a la que han sido sometidas, llegaron al pellizco en zonas que hacen ruborizar al mas convencido de los "machos".
Two Concepts of ‘Politicization’

Recent discussions of public affairs have frequently pointed to a ‘politicization’ of institutions, groups, and issues, such as the universities, the young and the black, and the quality of life. Insight into the concept of ‘politicization’ is often prevented by personal positions on the issues (or sympathies for particular parties to the dispute in question, or general psychic postures on political questions in general) and thus insight into the issues themselves is often obscured by narrow or unidirectional interpretation. In this essay I propose to identify and explore the meanings and nuances involved in the concept. I suggest, first, that there are two conflicting meanings of the term in use, and second, that the very use of the term, in either meaning, tends to take a position on several inevitable important problems of political of policy analysis.
IS LINEAR PENETRATION AN ACCURATE SURROGATE MEASURE FOR VOLUMETRIC WEAR IN TKR TIBIAL LINERS

Introduction Failure of total knee replacements due to the generation of polyethylene wear debris remains a crucial issue in orthopedics. Unlike the hip, it is difficult to accurately determine knee implant wear rates from retrieved components. Several studies have relied on thickness measurements to estimate penetration, but the complicated geometry of contemporary tibial liners poses a challenge to accurately assess wear. In this study we address the question whether linear penetration can serve as a surrogate measure for volumetric material loss. Methods Eighty-one retrieved UHMWPE NexGen cruciate-retaining tibial liners (Zimmer, Warsaw, IN) with an average time in situ of 5.27±2.89 years were included in the study. Metrology data for the surfaces of the tibial liners were obtained with a coordinate measuring machine (OGP, Rochester, NY). Using a laser scanner with two micrometer depth accuracy, at least 400,000 measurement points were taken by investigator #1. Areal thickness changes were mapped for the lateral and medial sides with the help of an autonomous mathematical reconstruction algorithm and volume loss was calculated based on wear scar area and local thickness change. Investigator #2, blinded from these results, measured the minimum thickness of the medial and lateral tibial plateau using a dial indicator with a spherical tip radius of 3mm. Twenty-three short term retrievals (3 to 4 per implant size), removed due to infection and without any signs of wear, served as “unused” reference. Linear penetration was then calculated by subtracting the minimum thickness of each plateau from the average thickness of the reference components. Results The autonomous reconstruction algorithm delivered results for all investigated components and wear maps could be generated in 100% of the cases. There was a linear association between volume loss and time in situ for the medial and lateral tibial plateau, respectively (R2=0.23, p Discussion There is a reasonable global correlation between linear penetration and volume loss. However, the uncertainty in obtaining a wear volume from an individual penetration value is relatively high. For example a penetration of 0.5 mm on the medial side correlates to a wear volume of 40 to 160 mm3. The large uncertainty might be because the location of the thickness minimum after wear does no longer coincide with the manufactured minimum of this device (Fig. 2). In conclusion, the results suggest that penetration is not a good surrogate measure for estimating wear volume of individual TKR polyethylene components, but might be a useful surrogate for large cohort studies.
Enhanced PET resolution by combining pinhole collimation and coincidence detection

Spatial resolution of clinical PET scanners is limited by detector design and photon non-colinearity. Although dedicated small animal PET scanners using specialized high-resolution detectors have been developed, enhancing the spatial resolution of clinical PET scanners is of interest as a more available alternative. Multi-pinhole 511 keV SPECT is capable of high spatial resolution but requires heavily shielded collimators to avoid significant background counts. A practical approach with clinical PET detectors is to combine multi-pinhole collimation with coincidence detection. In this new hybrid modality, there are three locations associated with each event, namely those of the two detected photons and the pinhole aperture. These three locations over-determine the line of response and provide redundant information that is superior to coincidence detection or pinhole collimation alone. Multi-pinhole collimation provides high resolution and avoids non-colinearity error but is subject to collimator penetration and artifacts from overlapping projections. However the coincidence information, though at lower resolution, is valuable for determining whether the photon passed near a pinhole within the cone acceptance angle and for identifying through which pinhole the photon passed. This information allows most photons penetrating through the collimator to be rejected and avoids overlapping projections. With much improved event rejection, a collimator with minimal shielding may be used, and a lightweight add-on collimator for high resolution imaging is feasible for use with a clinical PET scanner. Monte Carlo simulations were performed of a (18)F hot rods phantom and a 54-pinhole unfocused whole-body mouse collimator with a clinical PET scanner. Based on coincidence information and pinhole geometry, events were accepted or rejected, and pinhole-specific crystal-map projections were generated. Tomographic images then were reconstructed using a conventional pinhole SPECT algorithm. Hot rods of 1.4 mm diameter were resolved easily in a simulated phantom. System sensitivity was 0.09% for a simulated 70-mm line source corresponding to the NEMA NU-4 mouse phantom. Higher resolution is expected with further optimization of pinhole design, and higher sensitivity is expected with a focused and denser pinhole configuration. The simulations demonstrate high spatial resolution and feasibility of small animal imaging with an add-on multi-pinhole collimator for a clinical PET scanner. Further work is needed to develop geometric calibration and quantitative data corrections and, eventually, to construct a prototype device and produce images with physical phantoms.
Shockley-Ramo theorem and long-range photocurrent response in gapless materials

Scanning photocurrent maps of gapless materials, such as graphene, often exhibit complex patterns of hot spots positioned far from current-collecting contacts. We develop a general formalism that helps to explain the unusual features of the observed patterns, such as the directional effect and the global character of photoresponse. We show that this behavior is captured by a simple Shockley-Ramo-type framework. We examine specific examples and show that the photoresponse patterns can serve as a powerful tool to extract information about symmetry breaking, inhomogeneity, chirality, and other local characteristics of the system.
National Policy in the Promotion of Health

(1979). National Policy in the Promotion of Health. Journal of the Institute of Health Education: Vol. 17, No. 3, pp. 91-98.
Design, Synthesis, and Study of Fluorinated Proteins

Highly fluorinated analogs of hydrophobic amino acids have proven to be generally effective in increasing the thermodynamic stability of proteins. These non-proteogenic amino acids can be incorporated into both α-helix and β-sheet structural motifs and generally enhance protein stability towards unfolding by heat and chemical denaturants, and retard their degradation by proteases. Recent detailed structural and thermodynamic studies have demonstrated that the increase in buried hydrophobic surface area that accompanies fluorination is primarily responsible for the stabilizing properties of fluorinated side chains. Fluorination appears to be a particularly useful strategy for increasing protein stability because fluorinated amino acids closely retain the shape of the side chain, and are thus minimally perturbing to protein structure and function. The first part of this chapter discusses some examples of highly fluorinated model proteins designed by our laboratory and protocols for their synthesis. In the second part, methods for determining their thermodynamic stability, along with conditions that have proven to be useful for crystallizing these proteins, are presented.
Economic Potential for Distributed Manufacturing of Adaptive Aids for Arthritis Patients in the U.S

By 2040, more than a quarter of the U.S. population will have diagnosed arthritic conditions. Adults with arthritis and other rheumatic conditions earn less than average yet have medical care expenditures that are over 12% of average household income. Adaptive aids can help arthritis patients continue to maintain independence and quality of life; however, their high costs limit accessibility for older people and the poor. One method used for consumer price reduction is distributed manufacturing with 3-D printers. In order to assess if such a method would be financially beneficial, this study evaluates the techno-economic viability of distributed manufacturing of adaptive aids for arthritis patients. Twenty freely accessible designs for 3-D printable adaptive aids were successfully fabricated on low-cost desktop 3-D printers and performed their functions adequately. The financial savings averaged >94% compared to commercially-available products. Overall, twenty adaptive aids were printed for US$20 of plastic; while on average, each adaptive aid would save over US$20. As printing a tiny subset of the adaptive aids needed by a single patient would recover the full capital and operational costs of a low-cost 3-D printer, it can be concluded that there is considerable potential for distributed manufacturing to assist arthritis patients.
Market Efficiency and Arbitrage Opportunities for Russian Depositary Receipts Cross-Listed on the London Stock Exchange

This study examines the Russian stock market efficiency from two perspectives. First, we document that for the sample of Russian firms cross-listed on the Main Market of the London Stock Exchange (LSE) as Global Depositary Receipts (GDRs), the return series obtained from both the local market and the LSE are time-invariant and hence, predictable. This suggests that the market is inefficient with respect to pricing Russian GDRs and that investors are likely to make systematic nonzero profits. Second, we document profitable arbitrage opportunity surrounding the announcement to adopt IFRS, which is an additional evidence of market inefficiency. The significant pricing spread observed on this key date was due to the differential market reaction to IFRS adoption — neutral on the local MICEX exchange dominated by individual traders and significantly negative on the LSE dominated by institutional investors. This finding can be explained by (i) informational advantages of the local investors due to geographic proximity, (ii) differential expectations with respect to governance norms and listing requirements, and (iii) difference in portfolio composition of the two investor groups.
An Incentive-Compatible Scheme for Electricity Cooperatives: An Axiomatic Approach

This paper introduces a new scheme for autonomous electricity cooperatives, called predictive cooperative, which aggregates commercial and residential electricity consumers and participates in the electricity market on behalf of its members. An axiomatic approach is proposed to calculate the day-ahead bid and to disaggregate the collective cost among participating consumers. The resulting formulation is shown to keep the members incentivized to both participate in the cooperative and remain truthful in reporting their expected loads. The scheme is implemented using PJM (world’s largest wholesale electricity market) real-time and day-ahead price data for 2015 and a collection of residential and commercial load profiles. The model performance of this framework is compared to that of the real-time pricing scheme, in which wholesale market prices are directly applied to individual consumers. The results show truthful load announcement by consumers, reduction in electricity price variation for all consumers, and comparative benefits for participants.
Automating Carotid Intima-Media Thickness Video Interpretation with Convolutional Neural Networks

Cardiovascular disease (CVD) is the leading cause of mortality yet largely preventable, but the key to prevention is to identify at-risk individuals before adverse events. For predicting individual CVD risk, carotid intima-media thickness (CIMT), a noninvasive ultrasound method, has proven to be valuable, offering several advantages over CT coronary artery calcium score. However, each CIMT examination includes several ultrasound videos, and interpreting each of these CIMT videos involves three operations: (1) select three end-diastolic ultrasound frames (EUF) in the video, (2) localize a region of interest (ROI) in each selected frame, and (3) trace the lumen-intima interface and the media-adventitia interface in each ROI to measure CIMT. These operations are tedious, laborious, and time consuming, a serious limitation that hinders the widespread utilization of CIMT in clinical practice. To overcome this limitation, this paper presents a new system to automate CIMT video interpretation. Our extensive experiments demonstrate that the suggested system performs reliably. The reliable performance is attributable to our unified framework based on convolutional neural networks (CNNs) coupled with our informative image representation and effective post-processing of the CNN outputs, which are uniquely designed for each of the above three operations.
Analysis of Scanned Probe Images for Magnetic Focusing in Graphene

We have used cooled scanning probe microscopy (SPM) to study electron motion in nanoscale devices. The charged tip of the microscope was raster-scanned at constant height above the surface as the conductance of the device was measured. The image charge scatters electrons away, changing the path of electrons through the sample. Using this technique, we imaged cyclotron orbits that flow between two narrow contacts in the magnetic focusing regime for ballistic hBN–graphene–hBN devices. We present herein an analysis of our magnetic focusing imaging results based on the effects of the tip-created charge density dip on the motion of ballistic electrons. The density dip locally reduces the Fermi energy, creating a force that pushes electrons away from the tip. When the tip is above the cyclotron orbit, electrons are deflected away from the receiving contact, creating an image by reducing the transmission between contacts. The data and our analysis suggest that the graphene edge is rather rough, and electrons scattering off the edge bounce in random directions. However, when the tip is close to the edge, it can enhance transmission by bouncing electrons away from the edge, toward the receiving contact. Our results demonstrate that cooled SPM is a promising tool to investigate the motion of electrons in ballistic graphene devices.
A General Approach to Catalytic Alkene Anti-Markovnikov Hydrofunctionalization Reactions via Acridinium Photoredox Catalysis

ConspectusThe development of methods for anti-Markovnikov alkene hydrofunctionalization has been a focal point of catalysis research for several decades. The vast majority of work on the control of regioselectivity for this reaction class has hinged on transition metal catalyst activation of olefin substrates. While progress has been realized, there are significant limitations to this approach, and a general solution for catalysis of anti-Markovnikov hydrofunctionalization reactions of olefins does not presently exist.In the past several years, this research lab has focused on alkene activation by single electron oxidation using organic photoredox catalysts to facilitate anti-Markovnikov hydrofunctionalization. By accessing reactive cation radical intermediates, we have realized a truly general approach to anti-Markovnikov olefin hydrofunctionalization reactions. We have identified a dual organic catalyst system consisting of an acridinium photooxidant, first reported by Fukuzumi, and a redox-active hydro...
Calculational Design of Information Flow Monitors

Fine grained information flow monitoring can in principle address a wide range of security and privacy goals, for example in web applications. But it is very difficult to achieve sound monitoring with acceptable runtime cost and sufficient precision to avoid impractical restrictions on programs and policies. We present a systematic technique for design of monitors that are correct by construction. It encompasses policies with downgrading. The technique is based on abstract interpretation which is a standard basis for static analysis of programs. This should enable integration of a wide range of analysis techniques, enabling more sophisticated engineering of monitors to address the challenges of precision and scaling to widely used programming languages.
Stability of two-dimensional BN-Si structures

Two-dimensional (2D) ${\mathrm{BNSi}}_{2}$ has been recently proposed to be a viable candidate material with a graphenelike structure. We have carried out ab initio evolutionary ground state searches and uncovered a number of 2D structures in the $(\mathrm{BN}){}_{x}{\mathrm{Si}}_{1\ensuremath{-}x}$ pseudobinary system with considerably lower energies. Nevertheless, our formation energy analysis shows that none of these or previously proposed polymorphs are stable with respect to phase separation into 2D Si and BN. Examination of the related CSi, ${\mathrm{BNC}}_{2}$, and ${\mathrm{BNSi}}_{2}$ 2D compounds indicates that the lack of miscibility in the last two systems is due to limited involvement of nitrogen electronic states in the covalent bonding.
Integration and utilization of modern technologies in nephrolithiasis research

Nephrolithiasis, or stones, is one of the oldest urological diseases, with descriptions and treatment strategies dating back to ancient times. Despite the enormous number of patients affected by stones, a surprising lack of conceptual understanding of many aspects of this disease still exists. This lack of understanding includes mechanisms of stone formation and retention, the clinical relevance of different stone compositions and that of formation patterns and associated pathological features to the overall course of the condition. Fortunately, a number of new tools are available to assist in answering such questions. New renal endoscopes enable kidney visualization in much higher definition than was previously possible, while micro-CT imaging is the optimal technique for assessment of stone microstructure and mineral composition in a nondestructive fashion. Together, these tools have the potential to provide novel insights into the aetiology of stone formation that might unlock new prevention and treatment strategies, and enable more effective management of patients with nephrolithiasis.
Manifestations of isospin in nearest neighbor spacing distributions for the f-p model space

The strong interactions are charge independent. If we limit ourselves to the strong interactions, we have the isospin T as a good quantum number. Here, we consider the lack of level repulsion of st...
Learning from Errors.

Although error avoidance during learning appears to be the rule in American classrooms, laboratory studies suggest that it may be a counterproductive strategy, at least for neurologically typical students. Experimental investigations indicate that errorful learning followed by corrective feedback is beneficial to learning. Interestingly, the beneficial effects are particularly salient when individuals strongly believe that their error is correct: Errors committed with high confidence are corrected more readily than low-confidence errors. Corrective feedback, including analysis of the reasoning leading up to the mistake, is crucial. Aside from the direct benefit to learners, teachers gain valuable information from errors, and error tolerance encourages students’ active, exploratory, generative engagement. If the goal is optimal performance in high-stakes situations, it may be worthwhile to allow and even encourage students to commit and correct errors while they are in low-stakes learning situations rather...
The allure of the hidden: How product unveiling confers value☆

Abstract Different package designs call for different ways of revealing the product. In this research, we demonstrate that packaging that calls for unveiling—the removal of the cover of a concealed, stationary object—enhances the perceived value of the product compared to other forms of product revelation. Drawing on theories of grounded associations, shared meaning, and contagion, we theorize that the act of unveiling is associated with revealing a protected and thus pristine object, which is consequently perceived to be valuable. We begin the empirical investigation by exploring consumer associations with product unveiling across American and South Korean consumers (pilot study 1). We then demonstrate that the unveiling effect arises with both imagined (pilot study 2) and real objects and is mediated by beliefs about the pristine condition of the object (studies 1–3). We conclude with a discussion of the theoretical contributions, implications for managers, and directions for future research.
Comorbid Chronic Pain and Depression: Patient Perspectives on Empathy.

Abstract Clinician empathy is a well-documented component of effective patient/provider communication. Evidence surrounding the association between patient perspectives on clinician empathy and perception of pain management is currently limited, particularly among patients with chronic pain and depression. The aim of this study was to analyze patients' perspectives on the emergent theme of empathy and describe how patients construct their experiences and expectations surrounding empathic interactions. A secondary analysis of focus group data was designed using grounded theory methodology. Veterans Affairs (VA) and University Primary Care Clinics. Respondents with chronic pain and comorbid depression (N = 18) were 27 to 84 years old (mean 54.8 years), 61% women, 22% black, and 74% white. Study participants highly valued empathy and two types of empathic interactions: empathic listening and empathic action. Patients who provided examples of empathic interactions claimed that others understood, valued, and cared for them. In contrast, patients who perceived a lack of empathy and empathic interactions felt frustrated and uncared for by others (including their physicians) physically and emotionally. Patients with chronic pain and depression claimed that empathy helped them feel understood, believed, taken seriously, and that their needs were met. In demonstrating empathy and engaging in empathic interactions with patients, providers relate better to patients, better understand their life experience, and provide patient-centered care that is meaningful for patients, providers, and the health care systems within which they interact. Future research is needed to purposefully study the effects of empathic interactions on outcomes for patients with chronic pain and comorbid depression.
Trees, Paths, Stars, Caterpillars and Spiders

For any $$k \ge 2$$ , deciding whether the linear arboricity, star arboricity, caterpillar arboricity, spider arboricity, track number, unit track number, and subchromatic index, respectively, of a bipartite graph are at most k are all NP-complete.
Traumatic brain injury stimulates neural stem cell proliferation via mammalian target of rapamycin signaling pathway activation

Neural stem cells in the adult brain possess the ability to remain quiescent until needed in tissue homeostasis or repair. It was previously shown that traumatic brain injury (TBI) stimulated neural stem cell (NSC) proliferation in the adult hippocampus, indicating an innate repair mechanism, but it is unknown how TBI promotes NSC proliferation. In the present study, we observed dramatic activation of mammalian target of rapamycin complex 1 (mTORC1) in the hippocampus of mice with TBI from controlled cortical impact (CCI). The peak of mTORC1 activation in the hippocampal subgranular zone, where NSCs reside, is 24-48 h after trauma, correlating with the peak of TBI-enhanced NSC proliferation. By use of a Nestin-GFP transgenic mouse, in which GFP is ectopically expressed in the NSCs, we found that TBI activated mTORC1 in NSCs. With 5-bromo-2'-deoxyuridine labeling, we observed that TBI increased mTORC1 activation in proliferating NSCs. Furthermore, administration of rapamycin abolished TBI-promoted NSC proliferation. Taken together, these data indicate that mTORC1 activation is required for NSC proliferation postinjury, and thus might serve as a therapeutic target for interventions to augment neurogenesis for brain repair after TBI.
Providing expert advice by analogy for on-line help

One of the principal problems of online help is the mismatch between the specialized knowledge and technical vocabulary of experts who are providing the help, and the relative naivete of novices, who usually are often not in a position to understand solutions expressed by the expert in their own terms. Most of the interfaces are plagued by recurrent key problems: 1) elicitation - how to ask questions that enable the helper to make decisions, and at the same time, are understandable to the novice, and 2) explanation - how to explain rationale behind expert decisions in terms that the user can understand. One of the best ways to do this is for the expert to provide analogies in terms of Commonsense knowledge, which provide metaphors that help novices learn problem-solving skills. SuggestDesk is a system that acts as an advisor to an online technical support person. It uses a large Commonsense knowledge base to search for analogies between known technical problem-solution pairs, and situations and events in everyday life that can be used to explain them.
Black hole shadows in fourth-order conformal Weyl gravity

We calculate the characteristics of the “black hole shadow” for a rotating, neutral black hole in fourth-order conformal Weyl gravity. It is shown that the morphology is not significantly affected ...
A Model for Approximately Stretched-Exponential Relaxation with Continuously Varying Stretching Exponents

Relaxation in glasses is often approximated by a stretched-exponential form: $$f(t) = A \exp [-(t/\tau )^{\beta }]$$ . Here, we show that the relaxation in a model of sheared non-Brownian suspensions developed by Corte et al. (Nat Phys 4:420–424, 2008) can be well approximated by a stretched exponential with an exponent $$\beta $$ that depends on the strain amplitude: $$0.25< \beta < 1$$ . In a one-dimensional version of the model, we show how the relaxation originates from density fluctuations in the initial particle configurations. Our analysis is in good agreement with numerical simulations and reveals a functional form for the relaxation that is distinct from, but well approximated by, a stretched-exponential function.
Sentiment during Recessions

This paper studies the effect of sentiment on asset prices during the 20th century (1905 to 2005). As a proxy for sentiment, we use the fraction of positive and negative words in two columns of financial news from the New York Times. The main contribution of the paper is to show that, controlling for other well-known time-series patterns, the predictability of stock returns using news' content is concentrated in recessions. A one standard deviation shock to our news measure during recessions predicts a change in the conditional average return on the DJIA of 12 basis points over one day.
Transient stability enhancement of doubly fed induction machine-based wind generator by bridge-type fault current limiter

Transient stability is a major concern for doubly fed induction machine (DFIM). A DFIM based wind generator is readily affected by faults at the grid side, as it's stator windings are interfaced to grid. However, the wind generators need to remain connected and continue operation during faults at the grid side according to the grid code requirements. Therefore it is important to enhance the transient stability of the DFIM based wind generators. To achieve enhanced transient stability of the DFIM, a bridge-type fault current limiter (BFCL) is proposed in this work. Symmetrical as well as unsymmetrical faults were applied to the test system to check the efficacy of the BFCL in transient stability enhancement. Simulations were carried out in Matlab/Simulink environment. To demonstrate the effectiveness of the proposed BFCL, its performance is compared with that of the series dynamic braking resistor (SDBR). Simulation results show that the BFCL is a very effective device to attain better stabilization of the DFIM and outperforms the SDBR in all aspects.
Manifolds with many hyperbolic planes

Abstract We construct examples of complete Riemannian manifolds having the property that every geodesic lies in a totally geodesic hyperbolic plane. Despite the abundance of totally geodesic hyperbolic planes, these examples are not locally homogeneous.
Branching bandits and Klimov's problem: achievable region and side constraints

We consider the average cost branching bandits problem and its special case known as Klimov's problem. We consider the vector n whose components are the mean number of bandits (or customers) of each type that are present. We characterize fully the achievable region, that is, the set of all possible vectors n that can be obtained by considering all possible policies. While the original description of the achievable region involves exponentially many constraints, we also develop an alternative description that involves only O(R/sup 2/) variables and constraints, where R is the number of bandit types (or customer classes). We then consider the problem of minimizing a linear function of n subject to L additional linear constraints on n. We show that optimal policies can be obtained by randomizing between L+1 strict priority policies that can be found efficiently (in polynomial time) using linear programming techniques.
Quasi-variational inequalities with non-compact sets

In this paper, we first generalize a foundational quasi-variational inequality (Theorem 3) which plays a key role throughout this paper by relaxing the compactness condition. Then we set up general forms of (generalized) quasi-variational inequalities and obtain a series of existence theorems without the compactness assumption. Also, since many other quasi-variational inequalities in the literature are special cases of ours, they can be generalized by our results.
The Performance of Successive Interference Cancellation in Random Wireless Networks

This paper provides a unified framework to study the performance of successive interference cancellation (SIC) in wireless networks with arbitrary fading distribution and powerlaw path loss. An analytical characterization of the performance of SIC is given as a function of different system parameters. The results suggest that the marginal benefit of enabling the receiver to successively decode k users diminishes very fast with k, especially in networks of high dimensions and small path loss exponent. On the other hand, SIC is highly beneficial when the users are clustered around the receiver and/or very low-rate codes are used. In addition, with multiple packet reception, a lower per-user information rate always results in higher aggregate throughput in interference-limited networks. In contrast, there exists a positive optimal per-user rate that maximizes the aggregate throughput in noisy networks. The analytical results serve as useful tools to understand the potential gain of SIC in heterogeneous cellular networks (HCNs). Using these tools, this paper quantifies the gain of SIC on the coverage probability in HCNs with nonaccessible base stations. An interesting observation is that, for contemporary wireless systems (e.g., LTE and WiFi), most of the gain of SIC is achieved by canceling a single interferer.
MIMO Wireless Communications Under Statistical Queueing Constraints

The performance of multiple-input multiple-output (MIMO) wireless systems is investigated in the presence of statistical queueing constraints. Queuing constraints are imposed as limitations on buffer violation probabilities. The performance under such constraints is captured through the effective capacity formulation. A detailed analysis of the effective capacity is carried out in the low-power, wideband, and high signal-to-noise ratio (SNR) regimes. In the low-power analysis, expressions for the first and second derivatives of the effective capacity with respect to SNR at SNR = 0 are obtained under various assumptions on the degree of channel state information at the transmitter. Transmission strategies that are optimal in the sense of achieving the first and second derivatives are identified. It is shown that while the first derivative does not get affected by the presence of queueing constraints, the second derivative gets smaller as the constraints become more stringent. Through the energy efficiency analysis, this is shown to imply that the minimum bit energy requirements do not change with more strict limitations but the wideband slope diminishes. Similar results are obtained in the wideband regime if rich multipath fading is being experienced. On the other hand, sparse multipath fading with bounded number of degrees of freedom is shown to increase the minimum bit energy requirements in the presence of queueing constraints. Following the low-SNR study, the impact of buffer limitations on the high-SNR performance is quantified by analyzing the high-SNR slope and the power offset in Rayleigh fading channels. Finally, numerical results are provided to illustrate the theoretical findings, and to demonstrate the interactions between the queueing constraints and spatial dimensions over a wide range of SNR values.
Maximizing the impact of climate finance: Funding projects or pilot projects?

Abstract When and how should public agencies provide finance to the private sector in support of climate change mitigation and adaptation? We distinguish theoretically between pilot projects, whose main objective is to obtain information about the desirability of a climate-related project, and full projects, which are at-scale and are often quite risky. When a successful project has distinct private and public benefits, a publicly-funded subsidy may be warranted to induce a pilot project, a full project, or both. We draw on insights about the value of experimentation for entrepreneurship and raising private capital to derive insights about when subsidizing projects or pilots is more efficient. We find that pilot projects have many virtues not previously examined, and these often render them the optimal target of public subsidies to the private sector.
Charmonium spectrum and diffractive production in a light-front Hamiltonian approach

Abstract We study exclusive charmonium production in diffractive deep inelastic scattering and ultra-peripheral heavy-ion collisions within the dipole picture. The mass spectrum and light-front wavefunctions of charmonium are obtained from the basis light-front quantization approach, using the one-gluon exchange interaction plus a confining potential inspired by light-front holography. We apply these light-front wavefunctions to exclusive charmonium production. The resulting cross sections are in reasonable agreement with electron-proton collision data at HERA and ultra-peripheral nucleus collision measurements at RHIC and LHC. The charmonium cross-section has model dependence on the dipole model. We observe that the cross-section ratio of excited states to the ground state has a weaker dependence than the cross-section itself. We suggest that measurements of excited states of heavy quarkonium production in future electron-ion collision experiments will impose rigorous constraints on heavy quarkonium light-front wave-functions, thus improving our understanding of meson structure, which eventually will help us develop a precise description of the gluon distribution function in the small-x regime.
Resolution, overlay, and field size for lithography systems

Resolution, overlay, and field size limits for UV, X-ray, electron beam, and ion beam lithography are described. The following conclusions emerge in the discussion. 1) At 1-µm linewidth, contrast for optical projection can be higher than that for electron beam. 2) Optical cameras using mirror optics and deep UV radiation can potentially produce linewidths approaching 0.5 µm. 3) For the purpose of comparing the resolution of electron beam and optical exposure, it is useful to define the minimum linewidth as twice the linewidth at which the contrast of the exposure system has fallen to 30 percent. 4) X-ray lithography offers the highest contrast and resist aspect ratio for linewidths above about 0.1 µm, but for dimensions below 0.1 µm, highest aspect ratio is obtained with electron beam. 5) With electron beam exposure on a bulk sample, contrast for a 50-nm linewidth is the same as that for 1-µm linewidth, provided the resist is thin. Higher accelerating voltages make it easier to correct for proximity effects and to maintain resolution with thick resist. 6) Ultimately the range of secondary electrons limits resolution in electron beam lithography, just as the range of photoelectrons limits resolution in X-ray lithography. In both cases, minimum linewidth and spacing in dense patterns is about 20 nm. Resolution with ion beams will probably be about the same because the interaction range of the ions will be similar to the electrons.