Miracle-dz/UniFAR-FTUs huggingface dataset:
Model-free Variable Selection in Reproducing Kernel Hilbert Space

Variable selection is popular in high-dimensional data analysis to identify the truly informative variables. Many variable selection methods have been developed under various model assumptions. Whereas success has been widely reported in literature, their performances largely depend on validity of the assumed models, such as the linear or additive models. This article introduces a model-free variable selection method via learning the gradient functions. The idea is based on the equivalence between whether a variable is informative and whether its corresponding gradient function is substantially non-zero. The proposed variable selection method is then formulated in a framework of learning gradients in a flexible reproducing kernel Hilbert space. The key advantage of the proposed method is that it requires no explicit model assumption and allows for general variable effects. Its asymptotic estimation and selection consistencies are studied, which establish the convergence rate of the estimated sparse gradients and assure that the truly informative variables are correctly identified in probability. The effectiveness of the proposed method is also supported by a variety of simulated examples and two real-life examples.
Inheritance and Labor Supply

Using data from the Michigan Panel Study of Income Dynamics and from Federal Estate Tax returns, this paper investigates the labor disincentive caused by inheritance. The results are of interest for several reasons. Whether or not inheritances are a strong labor disincentive figures prominently in the controversy surrounding the relative importance of inheritances and life-cycle savings as sources of U.S. wealth. Also, the size of the disincentive is important in determining the relationship between inheritance and inequality. Our results indicate that inheritances do not lead to large reductions in the labor supply of men and married women. Family consumption increases after an inheritance, but again the effect is small.
Comparing Machine Learning Classifiers and Linear/Logistic Regression to Explore the Relationship between Hand Dimensions and Demographic Characteristics

Understanding the relationship between physiological measurements from human subjects and their demographic data is important within both the biometric and forensic domains. In this paper we explore the relationship between measurements of the human hand and a range of demographic features. We assess the ability of linear regression and machine learning classifiers to predict demographics from hand features, thereby providing evidence on both the strength of relationship and the key features underpinning this relationship. Our results show that we are able to predict sex, height, weight and foot size accurately within various data-range bin sizes, with machine learning classification algorithms out-performing linear regression in most situations. In addition, we identify the features used to provide these relationships applicable across multiple applications.
Parameter estimation of K distribution based on second-kind statistics

The parameters of K distribution are estimated in this paper, and the log-cumulant estimator is proposed based on second-kind statistics. The performance of the log-cumulant estimator is tested on the Monte Carlo simulations. Parameter estimation results demonstrate that the log-cumulant estimator leads to high estimation accuracy for the small values of the shape parameter.
Construction of weakly mixing diffeomorphisms preserving measurable Riemannian metric and smooth measure

We describe in detail a construction of weakly mixing $C^\infty$ diffeomorphisms preserving a smooth measure and a measurable Riemannian metric as well as ${\mathbb} Z^k$ actions with similar properties. We construct those as a perturbation of elements of a nontrivial non-transitive circle action. Our construction works on all compact manifolds admitting a nontrivial circle action. It is shown in the appendix that a Riemannian metric preserved by a weakly mixing diffeomorphism can not be square integrable.
Agricultural Credit and Economic Growth in Rural Areas

Purpose - – In this paper, the authors set out to establish if there is a link between finance and economic growth in rural areas. The purpose of this paper is to evaluate the relation between credit by major lenders in rural areas – commercial banks and Farm Credit System (FCS) institutions – and economic growth for the period 1991-2010. Design/methodology/approach - – The motivation for this work comes from empirical studies showing a link between economic development and financial system development as well as from work which highlights the positive role of long-term finance provided by banks. The authors use two alternative panel data sets and fixed effects models to estimate the causal effect of credit supply (with lagged explanatory variables) on agricultural GDP growth per rural resident. Findings - – The authors find a positive association between agricultural lending and agricultural GDP growth per rural resident with additional billion in loans (about a third of the actual average) associated with 7-10 percent higher state growth rate with this association stronger during the 1990s. Regional data confirm these results. The results point to a positive link between credit and economic growth in rural areas during that period, attributable to the lending by FCS institutions and by commercial banks. Research limitations/implications - – Data availability limits the scope of this paper. The authors use state level balance sheet data available for the 1991-2003 period and annual data for 2003-2010 period. An additional regional data set is constructed for 1991-2010 with more aggregated data for the ten USDA agricultural production regions. The small number of panels limits the ability to use more sophisticated econometric models and the choice of dependent variables that captures economic growth. Practical implications - – By provides evidence that agricultural finance and in particular lending contribute significantly to the growth of US agriculture, this paper contributes to the policy debate on weather support for agricultural finance initiatives is justified. Originality/value - – The authors are not aware of another study that has linked agricultural lending by commercial banks and FCS institutions to growth in rural areas in the USA.
Repetitive Transcranial Magnetic Stimulation in Cervical Dystonia: Effect of Site and Repetition in a Randomized Pilot Trial

Dystonia is characterized by abnormal posturing due to sustained muscle contraction, which leads to pain and significant disability. New therapeutic targets are needed in this disorder. The objective of this randomized, sham-controlled, blinded exploratory study is to identify a specific motor system target for non-invasive neuromodulation and to evaluate this target in terms of safety and tolerability in the cervical dystonia (CD) population. Eight CD subjects were given 15-minute sessions of low-frequency (0.2 Hz) repetitive transcranial magnetic stimulation (rTMS) over the primary motor cortex (MC), dorsal premotor cortex (dPM), supplementary motor area (SMA), anterior cingulate cortex (ACC) and a sham condition with each session separated by at least two days. The Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) score was rated in a blinded fashion immediately pre- and post-intervention. Secondary outcomes included physiology and tolerability ratings. The mean change in TWSTRS severity score by site was 0.25 ± 1.7 (ACC), -2.9 ± 3.4 (dPM), -3.0 ± 4.8 (MC), -0.5 ± 1.1 (SHAM), and -1.5 ± 3.2 (SMA) with negative numbers indicating improvement in symptom control. TWSTRS scores decreased from Session 1 (15.1 ± 5.1) to Session 5 (11.0 ± 7.6). The treatment was tolerable and safe. Physiology data were acquired on 6 of 8 subjects and showed no change over time. These results suggest rTMS can modulate CD symptoms. Both dPM and MC are areas to be targeted in further rTMS studies. The improvement in TWSTRS scores over time with multiple rTMS sessions deserves further evaluation. Trial Registration ClinicalTrials.gov NCT01859247
A Dynamic Volume–Return Relation and Investors' Positive Feedback Trading

With individual stocks, a larger increase in trading volume indicates a stronger short-term return persistence. A reason for this short-horizon ‘volume–return relation’ is that it can signal the existence of fundamental news, which can be gradually incorporated into stock price. In this study, we present another plausible explanation by considering investors' short-term positive feedback trading. First, through empirical analysis, we show that the volume–return relation remains strong among stocks for which there is little fundamental news. Through a model-based analysis, we demonstrate that positive feedback trading can cause this relation even when there is no news. Our findings raise the possibility that the short-horizon volume–return relation is also caused by short-term positive feedback trading.
A new algorithm for computing certified numerical approximations of the roots of a zero-dimensional system

This paper provides a new method for computing numerical approximations of the roots of a zero-dimensional system. It works on general systems, even those with multiple roots, and avoids any arbitrary choice of linear combination of the multiplication operators. It works by computing eigenvectors (or a basis of the full invariant subspaces). The sparsity/structure of the multiplication operators by one variable can also be taken into account.
On the Hansen-Jagannathan Distance with a No-Arbitrage Constraint

We provide an in-depth analysis of the theoretical and statistical properties of the Hansen-Jagannathan (HJ) distance that incorporates a no-arbitrage constraint. We show that for stochastic discount factors (SDF) that are spanned by the returns on the test assets, testing the equality of HJ distances with no-arbitrage constraints is the same as testing the equality of HJ distances without no-arbitrage constraints. A discrepancy can exist only when at least one SDF is a function of factors that are poorly mimicked by the returns on the test assets. Under a joint normality assumption on the SDF and the returns, we derive explicit solutions for the HJ distance with a no-arbitrage constraint, the associated Lagrange multipliers, and the SDF parameters in the case of linear SDFs. This solution allows us to show that nontrivial differences between HJ distances with and without no-arbitrage constraints can arise only when the volatility of the unspanned component of an SDF is large and the Sharpe ratio of the tangency portfolio of the test assets is very high. Finally, we present the appropriate limiting theory for estimation, testing, and comparison of SDFs using the HJ distance with a no-arbitrage constraint.
What Explains Minimal Usage of Minimum Tillage Practices in Zambia? Evidence from District-Representative Data.

Conservation farming (CF) practices are widely considered to be important components of sustainable agricultural development in Sub-Saharan Africa because of their potential to raise farm productivity and incomes while maintaining or improving soil quality and reducing vulnerability to variable climatic conditions. CF in Zambia can be traced to the 1980s when government, private sector, and donor communities started promoting CF as an alternative set of agronomic practices for Zambian smallholders (Haggblade and Tembo 2003).
Do Funds of Hedge Funds Add Value ? Evidence from their holdings ! !

We examine the value of fund of funds (FoFs) using a new database of the funds’ hedge fund holdings. This data allows a first ever look at the types of hedge funds that FoFs select, as well the ability to gauge the FoFs’ skill at hiring and firing hedge fund managers. We find that FoFs hire larger, younger, and more illiquid hedge funds that have positive past performance. FoFs select hedge funds with complementary contract features to their own (e.g., liquidity.) However, we are unable to detect skillful fund selection by FoFs. The hedge funds selected by FoFs significantly outperform their peers prior to being hired by a FoF. After they are hired however, these hedge funds perform no better than comparable funds. The lack of skill in hedge fund selection suggests FoFs add value through other channels. We find evidence that one of the primary sources of value added by FoFs comes via skillful monitoring of their underlying hedge fund investments. Specifically we find that hedge funds fired by FoFs subsequently perform significantly worse than other hedge funds. Additionally funds that are held by FoFs are less likely to fail. The hazard rate for hedge funds held by FoFs is 57% lower than other comparable hedge funds, and funds fired by FoFs have a 25% greater likelihood of failure than other funds.
A solar surface dynamo

Context. Observations indicate that the “quiet” solar photosphere outside active regions contains considerable amounts of magnetic energy and magnetic flux, with mixed polarity on small scales. The origin of this flux is unclear. Aims. We test whether local dynamo action of the near-surface convection (granulation) can generate a significant contribution to the observed magnetic flux. Methods. We have carried out MHD simulations of solar surface convection, including the effects of strong stratification, compressibility, partial ionization, radiative transfer, as well as an open lower boundary. Results. Exponential growth of a weak magnetic seed field (with vanishing net flux through the computational box) is found in a simulation run with a magnetic Reynolds number of about 2600. The magnetic energy approaches saturation at a level of a few percent of the total kinetic energy of the convective motions. Near the visible solar surface, the (unsigned) magnetic flux density reaches at least a value of about 25 G. Conclusions. A realistic flow topology of stratified, compressible, non-helical surface convection without enforced recirculation is capable of turbulent local dynamo action near the solar surface.
Changes in inventory management and the business cycle

“I remember one day in the summer of 1975 when a CBO [Congressional Budget Office] staffer returnedfrom a congressional hearing with some amazing news, Alan Greenspan, then President Gerald Ford’s chief economic adviseti hadjust testified that the recession was mostly an inventory correction. We all snickered at the idea that what was, up to then, the deepest recession since the Great Depression could have been ‘only’an inventory cycle. When I subsequently studied the data more carefully, howeverç I learned that Greenspan had been right. Like most of the recessions before and since, the 1973-5 contraction was dominated by changes in inventory investment,”
Physical Exercise Restores the Generation of Newborn Neurons in an Animal Model of Chronic Epilepsy

Neurogenesis impairment is associated with the chronic phase of the epilepsy in humans and also observed in animal models. Recent studies with animal models have shown that physical exercise is capable of improving neurogenesis in adult subjects, alleviating cognitive impairment and depression. Here, we show that there is a reduction in the generation of newborn granule cells in the dentate gyrus of adult rats subjected to a chronic model of epilepsy during the postnatal period of brain development. We also show that the physical exercise was capable to restore the number of newborn granule cells in this animals to the level observed in the control group. Notably, a larger number of newborn granule cells exhibiting morphological characteristics indicative of correct targeting into the hippocampal circuitry and the absence of basal dendrite projections was also observed in the epileptic animals subjected to physical exercise compared to the epileptic animals. The results described here could represent a positive interference of the physical exercise on the neurogenesis process in subjects with chronic epilepsy. The results may also help to reinterpret the benefits of the physical exercise in alleviating symptoms of depression and cognitive dysfunction.
The patient-provider relationship: attachment theory and adherence to treatment in diabetes.

OBJECTIVE Lack of adherence to diabetic self-management regimens is associated with a high risk of diabetes complications. Previous research has shown that the quality of the patient-provider relationship is associated with adherence to diabetes treatment. This study attempts to improve understanding of both patient and provider factors involved in lack of adherence to treatment in diabetic patients by using the conceptual model of attachment theory. METHOD Instruments that assessed attachment, treatment adherence, depression, diabetes severity, patient-provider communication, and demographic data were administered to 367 patients with type 1 and 2 diabetes in a health maintenance organization primary care setting. Glucose control, medical comorbidity, and adherence to medications and clinic appointments were determined from automated data. Analyses of covariance were used to determine if attachment style and quality of patient-provider communication were associated with adherence to treatment. RESULTS Patients who exhibited dismissing attachment had significantly worse glucose control than patients with preoccupied or secure attachment. An interaction between attachment and communication quality was significantly associated with glycosylated hemoglobin (Hb A(1c)) levels. Among the patients with a dismissing attachment style, there was a significant difference in glycosylated hemoglobin levels between those who rated their patient-provider communication as poor (mean=8.50%, SD=1.55%) and those who rated this communication as good (mean=7.49%, SD=1. 33%). Among all patients who were taking oral hypoglycemics, adherence to medications and glucose monitoring was significantly worse in patients who exhibited dismissing attachment and rated their patient-provider communication as poor. CONCLUSIONS Dismissing attachment in the setting of poor patient-provider communication is associated with poorer treatment adherence in patients with diabetes.
Dynamic Capital Structure and Stochastic Interest Rates

This study develops a model of dynamic capital structure in the presence of stochastic interest rates. Having separated the impact of firm characteristics, the paper shows that the optimal leverage and maturity are positively related to the short-term interest rates and negatively associated with the long-term interest rates. The volatility of interest rates affects the optimal leverage negatively. The optimal maturity is related to the volatility positively (negatively) when the yield curve is normal (inverted). The aforementioned are due to the changes in the firm's tax shields, bankruptcy costs and recapitalization costs caused by interest rate movements.
Power Allocation in Multi-Carrier Networks with Unicast and Multicast Services

Since the provision of both unicast and multicast services is expected for the next generation of multi-carrier wireless systems, the allocation of resources for this combination of services is a relevant topic, which may have a significant impact on the system performance. The focus of this work lies on the allocation of power to the different downlink subchannels of a multi-carrier system containing both unicast and multicast users. The power allocation problem is analyzed considering on the one hand the maximization of the sum throughput and on the other hand the maximization of the minimum SNR. The solution of the former is presented, which depends on numerical optimization, and an algorithm similar to the waterfilling hypothesis testing is proposed for reducing the processing time, while for the latter a closed-form solution is demonstrated. A simplified power allocation algorithm based on multicast group quality criteria is also evaluated and shown to approximate the maximal achievable performance under certain circumstances.
Software Architecture in Industrial Applications

To help us identify and focus on pragmatic and concrete issues related to the role of software architecture in large systems, we conducted a survey of a variety of software systems used in industrial applications. Our premise, which guided the examination of these systems, was that software architecture is concerned with capturing the structures of a system and the relationships among the elements both within and between structures. The structures we found fell into several broad categories: conceptual architecture, module interconnection architecture, code architecture, and execution architecture. These categories address different engineering concerns. The separation of such concerns, combined with specialized implementation techniques, decreased the complexity of implementation, and improved reuse and reconfiguration.
Reporting organisational performance in managing human resources: Intellectual capital or stakeholder perspectives?

Purpose – To examine how the performance of organisations in managing and utilising their human resources is disclosed through key performance indicator (KPI) reporting.Design/methodology/approach – Utilises intellectual capital (IC) and corporate social responsibility (CSR)/stakeholder perspectives in performing a content analysis of KPIs reported by Australian banks.Findings – Examining KPI reporting in relation to human resources across the sample of Australian banks indicates significant differences in the amount of KPIs reported and the focus of the KPIs reported, with the emphasis varying from disclosing the value derived from human capital to the value provided to employees and the broader society. Overall, the findings suggest the popularity of a stakeholder perspective in reporting on the management of human resources.Practical implications – Policy formulators and researchers need to investigate the benefits and cost of mandating or providing further guidance for extended performance reporting, .
Inter-Sector Relations in the Portuguese Economy: an Application of Contingent

1 Financial Stability Report November 2010 | Banco de Portugal * The author is thankful to Ana Cristina Leal, Nuno Alves, Mario Centeno, Nuno Ribeiro and Antonio Antunes for comments and suggestions. The author is also in debt to the Statistics Department of the Banco de Portugal for providing information on fi nancial accounts. The analysis, opinions and fi ndings of this article represent the views of the author, which are not necessarily those of Banco de Portugal or the Eurosystem. All errors and omissions are the sole responsibility of the author. ** Banco de Portugal, Economics and Research Department. INTER-SECTOR RELATIONS IN THE PORTUGUESE ECONOMY: AN APPLICATION OF CONTINGENT CLAIM ANALYSIS