Miracle-dz/UniFAR-FTUs huggingface dataset:
Weighted geometric set cover problems revisited

We study several set cover problems in low dimensional geometric settings. Specifically, we describe a PTAS for the problem of computing a minimum cover of given points by a set of weighted fat objects. Here, we allow the objects to expand by some prespecified δ-fraction of their diameter. Next, we show that the problem of computing a minimum weight cover of points by weighted halfplanes (without expansion) can be solved exactly in the plane. We also study the problem of covering ℝ d by weighted halfspaces, and provide approximation algorithms and hardness results. We also investigate the dual settings of computing minimum weight simplex that covers a given target point. Finally, we provide a near linear time algorithm for the problem of solving a LP minimizing the total weight of violated constraints needed to be removed to make it feasible.
Adaptive modulation using orthogonal STBC in MIMO Nakagami fading channels

Orthogonal space-time block coding (STBC) provides a full diversity gain over the MIMO fading channel while allowing simple linear decoding at the receiver. We consider adaptive modulation (AM) using STBC in the presence of Nakagami fading. For this type of fading channel, we first derive the outage and Shannon (ergodic) capacities of the STBC diversity scheme. We then assess the performance of AM using M-ary quadrature amplitude modulation (M-QAM) in terms of three metrics, namely, the outage probability, the average bit error rate (BER), and the average spectral efficiency. As a reference point, we also derive the average BER for nonadaptive binary phase shift keying (BPSK) used in conjunction with STBC. It is shown that AM allows the Shannon capacity of STBC to be approached and yields a significant performance enhancement compared to fixed modulation schemes.
Is integer arithmetic fundamental to mental processing?: the mind's secret arithmetic

Unlike the ability to acquire our native language, we struggle to learn multiplication and division. It may then come as a surprise that the mental machinery for performing lightning–fast integer arithmetic calculations could be within us all even though it cannot be readily accessed, nor do we have any idea of its primary function. We are led to this provocative hypothesis by analysing the extraordinary skills of autistic savants. In our view such individuals have privileged access to lower levels of information not normally available through introspection.
A new proof of Nash's Theorem via exchangeable equilibria

We give a novel proof of the existence of Nash equilibria in all finite games without using fixed point theorems or path following arguments. Our approach relies on a new notion intermediate between Nash and correlated equilibria called exchangeable equilibria, which are correlated equilibria with certain symmetry and factorization properties. We prove these exist by a duality argument, using Hart and Schmeidler’s proof of correlated equilibrium existence as a first step. In an appropriate limit exchangeable equilibria converge to the convex hull of Nash equilibria, proving that these exist as well. Exchangeable equilibria are defined in terms of symmetries of the game, so this method automatically proves the stronger statement that a symmetric game has a symmetric Nash equilibrium. The case without symmetries follows by a symmetrization argument.
Effects of thunderstorm‐driven runaway electrons in the conjugate hemisphere: Purple sprites, ionization enhancements, and gamma rays

The presence of energetic runaway electron beams above thunderstorms is suggested by observations of terrestrial gamma ray flashes [Fishman et al., 1994], as well as by theoretical work [Roussel-Dupre and Gurevich, 1996; Lehtinen et al., 1999], although such beams have not been directly measured. In this paper we consider possible measurable effects of such beams in the conjugate hemisphere as a means to confirm their existence and quantify their properties. High-density relativistic runaway electron beams, driven upward by intense lightning-generated mesospheric quasi-static electric fields, have been predicted [Lehtinen et al., 2000] to be isotropized and thermalized during their interhemispherical traverse along the Earth's magnetic field lines so that only ∼10% of the electrons which are below the loss cone should arrive at the geomagnetically conjugate ionosphere. As they encounter the Earth's atmosphere, the energetic electrons would be scattered and produce light and ionization, much like a beam of precipitating auroral electrons. A Monte Carlo approach is used to model the interaction of the downgoing electrons with the conjugate atmosphere, including the backscattering of electrons, as well as production of optical and gamma ray emissions and enhanced secondary ionization. Results indicate that these conjugate ionospheric effects of the runaway electron beam are detectable and thus may be used to quantify the runaway electron mechanism.
Ethnicity, Idiocentrism–Allocentrism, and Intergroup Attitudes1

The study examined the relationships among ethnicity, idiocentrism–allocentrism and intergroup attitudes in Singapore. Thirty Malay and 30 Chinese students completed questionnaires which measured in-group and out-group attitudes and attitudes toward ethnic-based community development groups. Intergroup attitudes were analyzed by a 2 × 2 × 2 (Subject Ethnicity × Target Group Ethnicity × Idiocentrism–Allocentrism) analysis of variance. A 2 × 2 interaction revealed that both Malay and Chinese subjects expressed ethnocentric biases; however, planned comparisons indicated that this was due to the responses of allocentrics. A separate 2 × 2 (Subject Ethnicity × Idiocentrism-Allocentrism) ANOVA further revealed that allocentrics had more favorable attitudes toward ethnic-based community development groups than did idiocentrics.
Endogenous Separation, Wage Rigidity and the Dynamics of Unemployment

This paper shows that the Mortensen-Pissarides (MP) model requires endogenous separation to explain the volatility of unemployment. I estimate a version of the MP model with wage rigidity and permanent shocks to match productivity. The model generates sufficient volatility in unemployment, vacancies, job-finding and job-separation despite relatively low worker outside options. I then re-estimate the model while restricting the separation rate to be constant and show that, even though the estimation procedure finds the best fitting model, the model predicts too little variance in unemployment and too much variance in the job-finding rate. Based on this result I conclude that models of unemployment fluctuations need endogenous separation rates to explain unemployment fluctuations.
Combination of image descriptors for the exploration of cultural photographic collections

Abstract. The rapid growth of image digitization and collections in recent years makes it challenging and burdensome to organize, categorize, and retrieve similar images from voluminous collections. Content-based image retrieval (CBIR) is immensely convenient in this context. A considerable number of local feature detectors and descriptors are present in the literature of CBIR. We propose a model to anticipate the best feature combinations for image retrieval-related applications. Several spatial complementarity criteria of local feature detectors are analyzed and then engaged in a regression framework to find the optimal combination of detectors for a given dataset and are better adapted for each given image; the proposed model is also useful to optimally fix some other parameters, such as the k in k-nearest neighbor retrieval. Three public datasets of various contents and sizes are employed to evaluate the proposal, which is legitimized by improving the quality of retrieval notably facing classical approaches. Finally, the proposed image search engine is applied to the cultural photographic collections of a French museum, where it demonstrates its added value for the exploration and promotion of these contents at different levels from their archiving up to their exhibition in or ex situ.
Robot homing based on corner tracking in a sequence of panoramic images

In robotics, homing can be defined as that behavior which enables a robot to return to its initial (home) position, after traveling a certain distance along an arbitrary path. Odometry has traditionally been used for the implementation of such a behavior, but it has been shown to be an unreliable source of information. In this work, a novel method for visual homing is proposed, based on a panoramic camera. As the robot departs from its initial position, it tracks characteristic features of the environment (corners). As soon as homing is activated, the robot selects intermediate target positions on the original path. These intermediate positions (IPs) are then visited sequentially, until the home position is reached. For the robot to move between two consecutive IPs, it is only required to establish correspondence among at least three corners. This correspondence is obtained through a feature tracking mechanism. The proposed homing scheme is based on the extraction of very low-level sensory information, namely the bearing angles of corners, and has been implemented on a robotic platform. Experimental results show that the proposed scheme achieves homing with a remarkable accuracy, which is not affected by the distance traveled by the robot.
Proinflammatory Cytokines and Early Neurological Worsening in Ischemic Stroke

Background and Purpose The mechanisms for clinical deterioration in patients with ischemic stroke are not completely understood. Several proinflammatory cytokines are released early after the onset of brain ischemia, but it is unknown whether inflammation predisposes to neurological deterioration. We assessed the implication of interleukin (IL)-6 and tumor necrosis factor (TNF)-&agr; in early neurological worsening in ischemic stroke. Methods Two hundred thirty-one patients consecutively admitted with first-ever ischemic cerebral infarction within the first 24 hours from onset were included. Neurological worsening was defined when the Canadian Stroke Scale (CSS) score fell at least 1 point during the first 48 hours after admission. IL-6 and TNF-&agr; were determined in plasma and cerebrospinal fluid (CSF; n=81) obtained on admission. Results Eighty-three patients (35.9%) deteriorated within the first 48 hours. IL-6 in plasma (>21.5 pg/mL; OR 37.7, CI 11.9 to 118.8) or in CSF (>6.3 pg/mL; OR 13.1, CI 2.2 to 77.3) were independent factors for early clinical worsening, with multiple logistic regression. The association was statistically significant in all ischemic stroke subtypes as well as in subjects with cortical or subcortical infarctions. IL-6 in plasma was highly correlated with body temperature, glucose, fibrinogen, and infarct volume. CSF and plasma concentrations of TNF-&agr; were also higher in patients who deteriorated, but the differences observed did not remain significant on multivariate analysis. Conclusions In addition to participating in the acute-phase response that follows focal cerebral ischemia, IL-6 levels on admission are associated with early clinical deterioration. The association between IL-6 and early neurological worsening prevails without regard to the initial size, topography, or mechanism of the ischemic infarction.
Rhythmic chewing with oral jaws in teleost fishes: a comparison with amniotes

SUMMARY Intra-oral prey processing (chewing) using the mandibular jaws occurs more extensively among teleost fishes than previously documented. The lack of muscle spindles, γ-motoneurons and periodontal afferents in fishes makes them useful for testing hypotheses regarding the relationship between these sensorimotor components and rhythmic chewing in vertebrates. Electromyography (EMG) data from the adductor mandibulae (AM) were used to quantify variation in chew cycle duration in the bowfin Amia, three osteoglossomorphs (bony-tongues), four salmonids and one esocid (pike). All species chewed prey using their oral jaw in repetitive trains of between 3 and 30 consecutive chews, a pattern that resembles cyclic chewing in amniote vertebrates. Variance in rhythmicity was compared within and between lineages using coefficients of variation and Levene's test for homogeneity of variance. These comparisons revealed that some teleosts exhibit degrees of rhythmicity that are comparable to mammalian mastication and higher than in lepidosaurs. Moreover, chew cycle durations in fishes, as in mammals, scale positively with mandible length. Chewing among basal teleosts may be rhythmic because it is stereotyped and inflexible, the result of patterned interactions between sensory feedback and a central pattern generator, because the lack of a fleshy tongue renders jaw–tongue coordination unnecessary and/or because stereotyped opening and closing movements are important for controlling fluid flow in the oral cavity.
Repeated implantation of skeletal myoblast in a swine model of chronic myocardial infarction.

AIMS Although transplantation of skeletal myoblast (SkM) in models of chronic myocardial infarction (MI) induces an improvement in cardiac function, the limited engraftment remains a major limitation. We analyse in a pre-clinical model whether the sequential transplantation of autologous SkM by percutaneous delivery was associated with increased cell engraftment and functional benefit. METHODS AND RESULTS Chronically infarcted Goettingen minipigs (n = 20) were divided in four groups that received either media control or one, two, or three doses of SkM (mean of 329.6 x 10(6) cells per dose) at intervals of 6 weeks and were followed for a total of 7 months. At the time of sacrifice, cardiac function was significantly better in animals treated with SkM in comparison with the control group. A significantly greater increase in the DeltaLVEF was detected in animals that received three doses vs. a single dose of SkM. A correlation between the total number of transplanted cells and the improvement in LVEF and DeltaLVEF was found (P < 0.05). Skeletal myoblast transplant was associated with an increase in tissue vasculogenesis and decreased fibrosis (collagen vascular fraction) and these effects were greater in animals receiving three doses of cells. CONCLUSION Repeated injection of SkM in a model of chronic MI is feasible and safe and induces a significant improvement in cardiac function.
Active site amino acid sequence of the bovine O6-methylguanine-DNA methyltransferase

An O6-methylguanine-DNA methyltransferase has been partially purified from calf thymus by conventional biochemical techniques. The enzyme was specifically radioactively labelled at the cysteine residue of the active site and further purified by attachment to a solid support. Following digestion with trypsin, a radioactive peptide containing the active site region of the protein was purified by size fractionation, ion exchange chromatography and reverse phase HPLC. The technique yielded an essentially homogeneous oligopeptide which was subjected to amino acid sequencing. The sequence adjacent to the acceptor cysteine residue of the bovine protein exhibits striking homology to the C-terminal methyl acceptor site of the E. coli Ada protein and the proposed acceptor sites of the E. coli Ogt and the B. subtilis Dat1 proteins.
Sectoral H-plane SBFSS-SIW horn antenna

A sectoral H-plane SIW horn antenna based on Stop-Band Frequency Selective Surface Substrate Integrated Waveguide technology is presented. The FSS operating in Stop-Band that replace the original metal conductor plates of the horn, increase the versatility of these structures, by making the direct integration of biased active and passive devices on its surface possible. The return losses, the radiation patterns and the E-field distribution on the surface of the proposed antenna have been compared with those of its counterpart SIW horn, to demonstrated that the new antenna can be used in the same role as the SIW horn with the advantage of having electrically isolated pads from ground on its surface.
Leptin inhibits amyloid β‐protein fibrillogenesis by decreasing GM1 gangliosides on the neuronal cell surface through PI3K/Akt/mTOR pathway

Leptin is a centrally acting hormone that controls metabolic pathways. Recent epidemiological studies suggest that plasma leptin is protective against Alzheimer's disease. However, the mechanism that underlies this effect remains uncertain. To investigate whether leptin inhibits the assembly of amyloid β‐protein (Aβ) on the cell surface of neurons, we treated primary neurons with leptin. Leptin treatment decreased the GM1 ganglioside (GM1) levels in the detergent‐resistant membrane microdomains (DRMs) of neurons. The increase in GM1 expression induced by leptin was inhibited after pre‐treatment with inhibitors of phosphatidylinositol 3‐kinase (LY294002), Akt (triciribine) and the mammalian target of rapamycin (i.e. rapamycin), but not by an inhibitor of extracellular signal‐regulated kinase (PD98059). In addition, pre‐treatment with these reagents blocked the induction of GM1 in DRMs by leptin. Furthermore, Aβ assembly on the cell surface of neurons was inhibited greatly after treatment with leptin. This reduction was markedly inhibited after pre‐treatment with LY294002, triciribine, and rapamycin. These results suggest that leptin significantly inhibits Aβ assembly by decreasing GM1 expression in DRMs of the neuronal surface through the phosphatidylinositol 3‐kinase/Akt/mammalian target of rapamycin pathway.
A model-driven framework for runtime adaptation of web service compositions

Many different approaches have been proposed towards the goal of flexible distributed heterogeneous interoperation of software systems using service composition techniques. Recent approaches are described in terms of higher level models rather than be coded at low level. Current practice, however, sees the service process specifications, written in BPEL or other languages, again as being largely hard-coded rather than exploiting the potential flexibility offered. We propose an approach that is influenced by related fields of model-driven development, conceptual modeling of business processes and workflows, semantic process descriptions and service matching through constraint satisfaction. They can be utilized in a complementary way to support dynamic, instance-based selection and composition of Web services, during runtime and extends this to provide self-modifying adaptation when circumstances change.
Your Relevance Feedback Is Essential: Enhancing the Learning to Rank Using the Virtual Feature Based Logistic Regression

Information retrieval applications have to publish their output in the form of ranked lists. Such a requirement motivates researchers to develop methods that can automatically learn effective ranking models. Many existing methods usually perform analysis on multidimensional features of query-document pairs directly and don't take users' interactive feedback information into account. They thus incur the high computation overhead and low retrieval performance due to an indefinite query expression. In this paper, we propose a Virtual Feature based Logistic Regression (VFLR) ranking method that conducts the logistic regression on a set of essential but independent variables, called virtual features (VF). They are extracted via the principal component analysis (PCA) method with the user's relevance feedback. We then predict the ranking score of each queried document to produce a ranked list. We systematically evaluate our method using the LETOR 4.0 benchmark datasets. The experimental results demonstrate that the proposal outperforms the state-of-the-art methods in terms of the Mean Average Precision (MAP), the Precision at position k (P@k), and the Normalized Discounted Cumulative Gain at position k (NDCG@k).
Preliminary UK experience of dexmedetomidine, a novel agent for postoperative sedation in the intensive care unit

Dexmedetomidine, a highly selective and potent α2‐adrenergic agonist, has a potentially useful role as a sedative agent in patients requiring intensive care. As part of a larger European multicentre trial, a total of 119 postoperative cardiac and general surgical patients requiring ventilation and sedation in an intensive care unit were enrolled in four centres in the United Kingdom. One hundred and five patients were randomly allocated to receive either dexmedetomidine or placebo with rescue sedation and analgesia provided by midazolam and morphine, respectively. Compared with the control group, intubated patients receiving dexmedetomidine required 80% less midazolam [mean 4.9 (5.8) μg. kg−1.h−1 vs. 23.7 (27.5) μg. kg−1.h−1, p < 0.0001], and 50% less morphine [11.2 (13.4) μg. kg−1.h−1 vs. 21.5 (19.4) μg. kg−1.h−1,p = 0.0006]. Cardiovascular effects and adverse events could be predicted from the known properties of alpha‐2 agonists. In conclusion, dexmedetomidine is a useful agent for the provision of postoperative analgesia and sedation.
Characteristics of the Work Environment Related to Older Employees' Willingness to Continue Working: Intrinsic Motivation as a Mediator:

Summary The relationships between older employees' willingness to continue working and characteristics of the work environment for older workers were investigated, as well as a possible mediation by intrinsic motivation. 103 employees ages 50 to 65 years, from various sectors of the Dutch labor market, completed questionnaires that measured willingness to continue working, intrinsic motivation, organizational stimulation, work variety, work challenge, and job autonomy. Hierarchical regression analyses showed organizational stimulation, as well as the various job characteristics, were positively related to employees' willingness to continue working. Moreover, intrinsic motivation fully mediated the relationship of work variety with willingness to continue working and partially mediated the relationships of organizational stimulation, work challenge, and job autonomy with willingness to continue working. It was concluded that organizations can encourage older workers to work until age 65 and beyond by shift.
The Level and Nature of Autistic

Autistics are presumed to be characterized by cognitive impairment, and their cognitive strengths (e.g., in Block Design performance) are frequently interpreted as low-level by-products of high-level deficits, not as direct manifestations of intelligence. Recent attempts to identify the neuroanatomical and neurofunctional signature of autism have been positioned on this universal, but untest- ed, assumption. We therefore assessed a broad sample of 38 autistic children on the preeminent test of fluid intelli- gence, Raven's Progressive Matrices. Their scores were, on average, 30 percentile points, and in some cases more than 70 percentile points, higher than their scores on the Wechsler scales of intelligence. Typically developing con- trol children showed no such discrepancy, and a similar contrastwasobservedwhenasampleofautisticadultswas comparedwithasampleofnonautisticadults.Weconclude that intelligence has been underestimated in autistics.