Miracle-dz/UniFAR-FTUs huggingface dataset:
From convex optimization to randomized mechanisms: toward optimal combinatorial auctions

We design an expected polynomial time, truthful in expectation, (1-1/e)-approximation mechanism for welfare maximization in a fundamental class of combinatorial auctions. Our results apply to bidders with valuations that are matroid rank sums (MRS), which encompass most concrete examples of submodular functions studied in this context, including coverage functions and matroid weighted-rank functions. Our approximation factor is the best possible, even for known and explicitly given coverage valuations, assuming P ≠ NP. Ours is the first truthful-in-expectation and polynomial-time mechanism to achieve a constant-factor approximation for an NP-hard welfare maximization problem in combinatorial auctions with heterogeneous goods and restricted valuations. Our mechanism is an instantiation of a new framework for designing approximation mechanisms based on randomized rounding algorithms. A typical such algorithm first optimizes over a fractional relaxation of the original problem, and then randomly rounds the fractional solution to an integral one. With rare exceptions, such algorithms cannot be converted into truthful mechanisms. The high-level idea of our mechanism design framework is to optimize directly over the (random) output of the rounding algorithm, rather than over the input to the rounding algorithm. This approach leads to truthful-in-expectation mechanisms, and these mechanisms can be implemented efficiently when the corresponding objective function is concave. For bidders with MRS valuations, we give a novel randomized rounding algorithm that leads to both a concave objective function and a (1-1/e)-approximation of the optimal welfare.
Psychophysical and cognitive aspects of categorical perception: A critical overview

Categorization is a very basic cognitive activity. It is involved in any task that calls for differential responding, from operant discrimination to pattern recognition to naming and describing objects and states-of-affairs. Explanations of categorization range from nativist theories denying that any nontrivial categories are acquired by learning to inductivist theories claiming that most categories are learned. "Categorical perception" (CP) is the name given to a suggestive perceptual phenomenon that may serve as a useful model for categorization in general: For certain perceptual categories, within-category differences look much smaller than between-category differences even when they are of the same size physically. For example, in color perception, differences between reds and differences between yellows look much smaller than equal-sized differences that cross the red/yellow boundary; the same is true of the phoneme categories /ba/ and /da/. Indeed, the effect of the category boundary is not merely quantitative, but qualitative.
Perceived Credibility of Male Versus Female Television Newscasters

Biological sex impacts people's perceptions of others, including their perceptions of how credible another person is. The purpose of this study was to determine if male or female television newscasters would be rated differently in their credibility when delivering the same message. After the researchers controlled for the physical attractiveness of the newscasters, a male and female newscaster were selected to read a 30-second weather-related newscast. Two groups of undergraduate students (N = 232) viewed a video of either a male or female newscaster reading the newscast, and then completed credibility measures. Results indicated that male newscasters were rated higher in competence, composure, and extroversion. No differences were found in character or sociability. Future research should address what about the sexes (e.g., attractiveness, vocal quality, traditional sex role expectations) influences perceptions of credibility.
Trade Agreements, Political Economy and Endogenously Incomplete Contracts

We develop a political economy model of trade agreements following along the line of Grossman and Helpman (1995a) yet incorporating contracting costs, uncertainty and multiple policy instruments. We show that rent-seeking efforts do not affect tariff rates as they are offset by the substitution effect of domestic production subsidies. Similar to Horn et al (2010), we find the coexistence of uncertainty and contracting costs make optimal trade agreements incomplete contracts. Our model helps explain differential treatment on subsidies, countervailing duties, and the national treatment principle - all key provisions of the current WTO agreement.
Geography and Electronic Commerce: Measuring Convenience, Selection, and Price

We develop a formal model of online-offline retail channel substitution to identify three factors that drive consumers to purchase online: convenience, selection, and price. This model builds hypotheses on how features of offline retail supply impact online purchasing. We then examine how the local availability of offline retail options drives use of the online channel and consequently how the convenience, selection, and price advantages of the online channel may vary by geographic location. In particular, we examine the effect of local store openings on online book purchases in that location. We explore this problem using data from Amazon on the top selling books for 1501 unique locations in the US for 10 months ending in January 2006. In addition to this data, we use information on changes in local retail competition as measured by openings of large bookstores such as Borders or Barnes & Noble and discount stores such as Wal-Mart or Target. We show that even controlling for product-specific preferences by location, changes in local retail options have substantial effects on online purchases. We demonstrate how the convenience, selection, and price benefits of the Internet are different for consumers in different types of locations. More generally, we show that geography significantly impacts the benefit that consumers derive from electronic markets.
Perception spatiale et compétences motrice : approche développement et neuropsychologique

Les theories qui modelisent la perception spatiale chez l'adulte s'accordent a postuler l'existence de liens forts entre la perception et l'action(James, 1892 ; Poincare, 1902 ; Gibson, 1979 ; Noe, 2004). Une vaste collection de donnees montre egalement que ces liens sont presents dans le developpement ontogenetique. Ce travail de these vise a examiner les implications de tels liens dans le developpement de la perception spatiale et d'en identifier les determinants chez l'enfant. Nous avons mene une serie d'experiences, basee sur l'utilisation des paradigmes d'atteignabilite et d'amorcage visuomoteur, autour de la problematique de l'elaboration et l'utilisation des representations perceptives et sensorimotrices dans la perception spatiale. Nous avons mene ces experiences chez une population d'adultes et d'enfants âgees de 7 a 13 ans avec l'objectif d'evaluer la trajectoire developpementale de la perception spatiale. Les resultats obtenus mettent en evidence des discontinuites dans les trajectoires developpementales des differentes tâches proposees. Nous avons mis en evidence les marqueurs de ces changements developpementaux dans les performances des tâches d'atteignabilite, d'imagerie motrice et egalement d'amorcage visuomoteur. Nous interpretons ces resultats comme relevant d'un changement qualitatif de la perception spatiale durant cette periode. D'une maniere generale, les travaux presentes dans cette these apportent des donnees nouvelles sur le developpement de la perception spatiale chez l'enfant, et sont mis en relation avec la litterature en psychologie et en neurosciences du developpement.
Commitment as a moderator of the goal−performance relation: a case for clearer construct definition

A central assumption in the goal theory literature is that the degree of commitment to the assigned goal moderates the effectiveness of the goal-setting procedure. However, attempts to empirically verify commitment's moderating role have generally met with failure, calling into question either widely used measures of goal commitment, the moderating assumption itself, or both. Three studies are described that address this issue. Results indicated that the moderation assumption is valid but is only relevant to one of three closely related motivational concepts that are commonly discussed under the heading of commitment: prechoice attitudes, the subsequent choice of a personal goal, and the maintenance of that choice
The potential therapeutic value of therapist stuckness in systemic practice

Theory development and research within the sphere of family therapy is an expression of who we are, where we are, and where our next horizon may lead us. The dialogical perspective introduces a new horizon to the systemic paradigm, a shift that supports new ways of observing practice. This project explored therapist stuckness, one aspect of the impasse phenomena, through this new lens. In response, the project introduced an alternative consultation model. The task of the model is to support a therapist when they encounter a stuck phase in therapy. Thus, the principal aim of this qualitative project was to ascertain if a consultation model influenced by the aforementioned perspective supports a therapist who is experiencing a stuck phase and if the stuck phenomenon is of value to the therapeutic process. Action Research methodology directed this inquiry. The research followed an action/reflexive cyclical trajectory with a marked responsiveness to the participant’s ideas and experiences as they engaged in the consultation and the participant/researcher dialogue. Hence, the primary method of data gathering entailed the engagement of family therapists in a consultation lead by the model. Each participant engaged in one consultation and one post consultation review. The analysis was directed through a synergy of lenses, namely: Interpretative Phenomenology Analysis, a dialogical lens and a Gadamerian Hermeneutic reflexive framework. The outcome of the analysis was translated through the Action Research lens with the outcome modifying the model format as required. The findings revealed that therapist stuckness could be described as a multi-positioned, responsive process. This description demonstrates the complex relationship between the therapist and client group. The description points towards the need to address stuckness in a way that observes how the therapist and client group connect and participate in the therapeutic trajectory. The developed Dialogical Consultation Model attempts to address this task. From this research, it is envisaged that the developed consultation model will provide a platform to develop a more advanced reflexive supervisory tool for use in systemic training and general systemic practice
Coming to America: challenges and difficulties faced by African student athletes

There is a considerable lack of literature on international student athletes despite the extent to which colleges and universities are increasingly relying on them to heighten the winning reputation of their sports programs. This research focuses on international student athletes from Africa. Based on interviews of 16 student athletes from seven different African countries, the range of their experiences upon entering universities in the United States, particularly their challenges, were identified. Many of the serious issues affecting the student athletes were matters related to the host environment's underestimations about the African student athletes’ desires to learn, misunderstandings about their culture and religions and other negative assumptions that undermined their academic success. We also found that the vast majority of these student athletes experienced negative stereotypes and discrimination based on their race and their region of origin.
Contract platform and tools

This paper describes a specification language for platforms using contracts. We provide the intuitive explanation of what a contract-based platform is as well as the formal analysis. By using Satisfiability Modulo Theories tools, architectures or detailed designs derived from such platforms can be verified automatically. A tool is presented that allows users to design platform components and rules and verify designs based on such platforms. The tool also assists users to identify possible design changes that enable automatic verification. The approach is illustrated using an example electrical power system.
Effects of Corporate Social Responsibility on Corporate Financial Performance: A Competitive-Action Perspective

We attempt to provide a more nuanced view of the relationship between corporate social responsibility (CSR) and firm financial performance using a competitive-action perspective. We argue that competitive action should be considered as an important contingency that determines the effects of CSR activities on firm financial performance. Using data for 113 publicly listed U.S. firms in the software industry between 2000 and 2005, we found that socially responsible activities (positive CSR) enhance firm financial performance when the firm’s competitive-action level is high, whereas socially irresponsible activities (negative CSR) actually improve firm financial performance when the competitive-action level is low. By introducing competitive action as an important contingency, this study contributes to the literature on CSR and strategic management.
That's Our Turf! Identity Domains and Competitive Dynamics

We examine the effects of organizational identity on the competitive dynamics of firms. Identity increases the awareness, motivation, and capability to respond to competitors' actions within the firm's identity domain, defined as cognitive competitive space that holds psychological value for a focal firm's management. Because of the psychological and motivational importance of a firm's identity, we predict that the actions and reactions within an identity domain may not adhere to traditional economically based explanations of managerial behavior.
Better matching with fewer features: The selection of useful features in large database recognition problems

There has been recent progress on the problem of recognizing specific objects in very large datasets. The most common approach has been based on the bag-of-words (BOW) method, in which local image features are clustered into visual words. This can provide significant savings in memory compared to storing and matching each feature independently. In this paper we take an additional step to reducing memory requirements by selecting only a small subset of the training features to use for recognition. This is based on the observation that many local features are unreliable or represent irrelevant clutter. We are able to select “useful” features, which are both robust and distinctive, by an unsupervised preprocessing step that identifies correctly matching features among the training images. We demonstrate that this selection approach allows an average of 4% of the original features per image to provide matching performance that is as accurate as the full set. In addition, we employ a graph to represent the matching relationships between images. Doing so enables us to effectively augment the feature set for each image through merging of useful features of neighboring images. We demonstrate adjacent and 2-adjacent augmentation, both of which give a substantial boost in performance.
The P300 Wave of the Human Event‐Related Potential

The P300 wave is a positive deflection in the human event-related potential. It is most commonly elicited in an “oddball” paradigm when a subject detects an occasional “target” stimulus in a regular train of standard stimuli. The P300 wave only occurs if the subject is actively engaged in the task of detecting the targets. Its amplitude varies with the improbability of the targets. Its latency varies with the difficulty of discriminating the target stimulus from the standard stimuli. A typical peak latency when a young adult subject makes a simple discrimination is 300 ms. In patients with decreased cognitive ability, the P300 is smaller and later than in age-matched normal subjects. The intracerebral origin of the P300 wave is not known and its role in cognition not clearly understood. The P300 may have multiple intracerebral generators, with the hippocampus and various association areas of the neocortex all contributing to the scalp-recorded potential. The P300 wave may represent the transfer of information to consciousness, a process that involves many different regions of the brain.
Peripheral Flow Response to Transient Arterial Forearm Occlusion Does Not Reflect Myocardial Perfusion Reserve

Background —Ultrasonographic evaluation of systemic arterial function is widely available, and a close relation of endothelial function in the coronary and brachial arteries has been documented. It is unknown, however, whether a similar correlation exists for their 2 microcirculatory territories and thus whether assessment of the systemic microcirculation can be used similarly as a surrogate marker of myocardial perfusion. Methods and Results —Twenty-three patients with documented coronary artery disease (CAD; 66±9 years old, 18 men), 16 patients with syndrome X (SX; 56±5 years old, 13 women), and 45 healthy control subjects (C; 34±9 years old, 22 men) were studied. Myocardial perfusion was measured at rest and after dipyridamole (0.56 mg · kg−1 · min−1 over 4 minutes) by PET, and brachial artery blood flow was measured at rest and after transient forearm ischemia by standard Doppler ultrasound techniques. Dipyridamole increased myocardial perfusion in all groups (mL · g−1 · min−1: CAD, 0.89±0.27 versus 1.62±0.67, P <0.001; SX, 0.82±0.16 versus 1.67±0.49, P <0.001; and C, 0.82±0.15 versus 2.32±0.64, P <0.001). Postocclusion forearm flow increased similarly in all groups (CAD, 52±18 versus 174±77 mL/min, P <0.001; SX, 49±29 versus 202±82 mL/min, P <0.001; and C, 61±34 versus 229±108 mL/min, P <0.001). No significant correlations were found between peripheral and myocardial microcirculatory beds for either resting flow, hyperemic flow, or flow reserve in any of the groups (r2<0.1, P =NS). Conclusions —The peripheral perfusion responses to transient forearm ischemia do not correlate with dipyridamole-induced myocardial hyperemia. The lack of correlation indicates different mechanisms of microvascular activation or regulation and confirms that extrapolations between findings in the 2 vascular beds are not suitable.
Analyzing Disclosure Practice of Religious Nonprofit Organizations using Partial Disclosure Index

This study examines the relevance of disclosure practices in improving the accountability and transparency of religious nonprofit organizations (RNPOs). The assessment of disclosure is based on the annual returns of RNPOs for the financial year 2010. In order to quantify the information disclosed in the annual returns, partial disclosure indexes of basic information (BI) disclosure index, financial information (FI) disclosure index and governance information (GI) disclosure index have been built which takes into account the content of information items in the annual returns. The empirical evidence obtained revealed low disclosure practices among RNPOs in the sample. The multiple regression results showed that the organizational attribute of the board size appeared to be the most significant predictor for both partial index on the extent of BI disclosure index, and FI disclosure index. On the other hand, the extent of financial information disclosure is related to the amount of donation received by RNPOs. On GI disclosure index, the existence of an external audit appeared to be significant variable. This study has contributed to the academic literature in providing empirical evidence of the disclosure practices among RNPOs. Keywords—disclosure, index, partial, NPOs, religious
Relationship of hypersensitivity to anxiety and depression in children with high‐functioning pervasive developmental disorders

Aims: Sensory–perceptual abnormalities, which include hyper‐ and hyposensitivity, have been identified by numerous researchers as prevalent in individuals with pervasive developmental disorders (PDD). Hypersensitivity has a greater impact on PDD patients' daily lives than hyposensitivity. The purpose of the present study was to clarify the relationship of hypersensitivity to anxiety, depression and other psychopathology in children with PDD.
Preventing Ventilator-Associated Pneumonia: An Evidence-Based Approach of Modifiable Risk Factors

There is considerable evidence to suggest that specific interventions can be effectively employed to prevent hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP). These interventions consist of pharmacological and nonpharmacological strategies that focus on prevention of aerodigestive tract colonization and the prevention of aspiration of contaminated secretions, the major pathogenetic mechanisms leading to HAP. Important components of effective preventive strategies focus on basic infection control principles like handwashing, adequate intensive care unit (ICU) staff education, and optimal resource utilization. Measures to prevent HAP/VAP extend into all aspects of daily intensive care practice, including antibiotic selection and duration of use, preferred routes of intubation, limitation of sedation, protocolized weaning, optimal use of noninvasive mask ventilation, patient positioning, ventilator circuit management, transfusion practices, nutritional support issues, stress ulcer prophylaxis, and glycemic control. Local programs encompassing these interventions should be applied at a multidisciplinary level, involve all caregivers, and include local surveillance programs for antibiotic-resistant bacteria. The importance of implementing preventive strategies is amplified by the anticipated limited availability of new antimicrobial drug classes for the foreseeable future. Effective implementation of these preventive principles can result in significant cost savings for society and reduce hospital mortality and morbidity for individual patients.
Movements to some purpose? An exploration of international retirement migration in the European Union

Drawing on a set of 210 qualitative interviews conducted in six European countries, this article explores the dynamics of international retirement migration (IRM) in relation to EU nationals within Europe. Initially, the extent of such migration is briefly considered. The main body of the article provides a more detailed exploration of the motivational factors that influence retired EU migrants’ decisions to relocate. Using qualitative data some important factors that precipitate movement are considered. Specific attention is given to the impact that concerns about accessing welfare, in particular health/care and pensions systems, may have on older citizens’ movements within Europe.
Fathers and Their Children After Divorce

The long-term tendency for numbers of divorces to rise and, as a consequence, for the percentage of families headed by mothers to rise, is creating a problem with respect to the material support of children without fathers, because in almost 99 percent of cases children remain with their mothers. The heightened risk of poverty for children in incomplete families is linked, in no small measure, to the inadequate amount and, very often, the irregularity of alimony and child-support payments that are intended, at least in part, to make up for the family's reduced income after a divorce.1