Miracle-dz/UniFAR-FTUs huggingface dataset:
Texture segmentation using globally active contours model and Cauchy-Schwarz distance

We present a new unsupervised segmentation based active contours model and local region texture descriptor. The proposed local region texture descriptor intrinsically describes the geometry of textural regions using the shape operator defined in Beltrami framework. The local texture descriptor is incorporated in the active contours using the Cauchy-Schwarz distance. The texture is discriminated by maximizing distance between the probability density functions which leads to distinguish textural objects of interest and background. We propose a fast Bregman split implementation of our segmentation algorithm based on the dual formulation of the Total Variation norm. Finally, we show results on some challenging images to illustrate segmentations that are possible.
Earnings Restatements, the Sarbanes-Oxley Act and the Disciplining of Chief Financial Officers

We investigate involuntary chief financial officer (CFO) turnover following earnings restatements, the labor market penalties imposed on former restatement-firm CFOs, and whether these disciplinary consequences have increased following the passage of the Sarbanes-Oxley Act of 2002 (SOX). Our results suggest that, relative to a control group of non-restating firms, firms restating earnings have higher rates of involuntary CFO turnover, and that former restatement-firm CFOs face stiff labor market penalties. We generally find that the passage of SOX has not increased involuntary CFO turnover rates following restatements. However, we find that labor market penalties for former CFOs of restatement firms are more severe in the post-SOX period, suggesting that SOX has increased ex post settling up costs. Our results suggest that the influence of SOX on the labor market has resulted in CFOs being held more accountable for their actions.
Some conversational challenges of talking with machines

A surge of interest in the capabilities of so-called 'conversational' technologies—both from research and industrial contexts—furnishes CSCW and HCI with opportunities to enrich and leverage its historic connection to conversation analysis (and relatedly, ethnomethodology) in novel ways. This paper explores a number of preliminary interactional troubles one might encounter when 'talking to' conversational agents, and in doing so sketches out possible routes forward in the empirical study of agents as collaborative technologies, as well as touching on further conceptual challenges that face research in this area.
Homophily or Influence ? An Empirical Analysis of Purchase within a Social Network

Consumers that are close to one another in a social network are known to have similar behaviors. The focus of this study is the extent to which such observed similarity is driven by homophily or social influence. Homophily refers to the similarity in product preferences between individuals who are connected. Social influence is the dependence of consumers’ purchase decisions on their communication with others. We construct a hierarchical Bayesian model to study both the timing and choice of consumer purchases within a social network. Our model is estimated using a unique social network dataset obtained from a large Indian telecom operator for the purchase of caller ringer-back tones. We find strong social influence effects in both the purchase-timing and product-choice decisions of consumers. In the purchase-timing decision, we find that consumers are three times more likely to be influenced by network neighbors than by other people. In the product-choice decision we find a strong homophily effect. We show that ignoring either homophily or social influence will result in overestimated effects of the other factor. Furthermore, we show that detailed communication data is crucial for measuring influence effect, and influence effect can be either overor underestimated when such data is not available. Finally, we conduct policy simulations on a variety of target marketing schemes to show that promotions targeted using network information is superior. For example, we find a 4-21% improvement on purchase probability, and an 11-35% improvement for promoting a specific product.
Analysis of Short-term Selection Experiments: 1. Least-squares Approaches

This chapter examines short-term (a few generations) selection response in the mean of a trait. Traditionally, such experiments are analyzed using least-squares (LS) approaches. While ordinary LS (OLS) is often used, genetic drift causes the residual to be both correlated and heteroscedastic, resulting in the sampling variances given by OLS being too small. This chapter details the appropriate general LS (GLS) approaches to properly account for this residual error structure. It also reviews some of the common features observed in short-term selection experiments and examines experimental designs, such as the use of a control population versus a divergence-selection approach. It concludes by discussing another linear model used mainly by plant breeders, generation-means analysis (GMA), wherein remnant seed for several generations of response are crossed and then grown in a common garden. Such an analysis can provide insight into the genetic nature of any response.
Leptin Promotes cPLA2 Gene Expression through Activation of the MAPK/NF-κB/p300 Cascade

Hyperplasia or hypertrophy of adipose tissues plays a crucial role in obesity, which is accompanied by the release of leptin. Recently, obesity was determined to be associated with various pulmonary diseases including asthma, acute lung injury, and chronic obstructive pulmonary disease. However, how obesity contributes to pulmonary diseases and whether leptin directly regulates lung inflammation remains unclear. We used cell and animal models to study the mechanisms of leptin mediation of pulmonary inflammation. We found that leptin activated de novo synthesis of cytosolic phospholipase A2-α (cPLA2-α) in vitro in the lung alveolar type II cells, A549, and in vivo in ICR mice. Upregulated cPLA2-α protein was attenuated by pretreatment with an OB-R blocking antibody, U0126, SB202190, SP600125, Bay11-7086, garcinol, and p300 siRNA, suggesting roles of p42/p44 MAPK, p38 MAPK, JNK1/2, NF-κB, and p300 in leptin effects. Leptin enhanced the activities of p42/p44 MAPK, p38 MAPK, JNK1/2, and p65 NF-κB in a time-dependent manner. Additional studies have suggested the participation of OB-R, p42/p44 MAPK, and JNK1/2 in leptin-increased p65 phosphorylation. Furthermore, p300 phosphorylation and histone H4 acetylation were reduced by blockage of OB-R, p42/p44 MAPK, p38 MAPK, JNK1/2, and NF-κB in leptin-stimulated cells. Similarly, blockage of the MAPKs/NF-κB/p300 cascade significantly inhibited leptin-mediated cPLA2-α mRNA expression. Our data as a whole showed that leptin contributed to lung cPLA2-α expression through OB-R-dependent activation of the MAPKs/NF-κB/p300 cascade.
Simulating the Seasonal Cycle of the Northern Hemisphere Storm Tracks Using Idealized Nonlinear Storm-Track Models

Abstract In this study, an idealized nonlinear model is used to investigate whether dry dynamical factors alone are sufficient for explaining the observed seasonal modulation of the Northern Hemisphere storm tracks during the cool season. By construction, the model does an excellent job simulating the seasonal evolution of the climatological stationary waves. Yet even under this realistic mean flow, the seasonal modulation in storm-track amplitude predicted by the model is deficient over both ocean basins. The model exhibits a stronger sensitivity to the mean flow baroclinicity than observed, producing too-large midwinter eddy amplitudes compared to fall and spring. This is the case not only over the Pacific, where the observed midwinter minimum is barely apparent in the model simulations, but also over the Atlantic, where the October/April eddy amplitudes are also too weak when the January amplitude is tuned to be about right. The nonlinear model generally produces stronger eddy amplitude with stronger b.
The E ¤ ect of Country Labor Regulation on Corporate Group A ¢ liation : Evidence from Europe

This paper investigates the e¤ect of country labor regulation on the formation of corporate groups. While employment regulations in some European countries impose substantial constraints on external labor markets, these regulations do not apply to internal labor markets of corporate groups. Using a comprehensive rm-level dataset covering 15 West-European countries, we test whether internal labor market considerations a¤ect the propensity of rms to belong to corporate groups. We nd that countries with high employment regulations have a higher percentage of group a¢ liates in industries with higher rate of labor turnover. This result is especially strong for a¢ liates of large and diversi ed groups. By assessing the strategic response of rms to increased country regulations, we identify conditions under which both rm large size and active internal labor markets may be the source of long-term competitive advantage. Keywords: Internal labor markets, country labor regulations, corporate group a¢ liation JEL Classi cation: J08, J40, L22, M51
Open/Closed String Dualities and Seiberg Duality from Geometric Transitions in M-theory

We propose a general method to study open/closed string dualities from transitions in M theory which is valid for a large class of geometrical configurations. By T-duality we can transform geometrically engineered configurations into = 1 brane configurations and study the transitions of the corresponding branes by lifting the configurations to M-theory. We describe the transformed degenerated M5 branes and extract the field theory information on gluino condensation by factorization of the Seiberg-Witten curve. We also include massive flavors and orientifolds and discuss Seiberg duality which appears in this case as a birational flop. After the transition, the Seiberg duality becomes an abelian electric-magnetic duality.
Spiral shocks, triggering of star formation and the velocity dispersion in giant molecular clouds

We present numerical simulations of the passage of gas through a galactic spiral shock and the subsequent formation of giant molecular clouds (GMCs), and the triggering of star formation. In these simulations, we take account of the observed inhomogeneity, or clumpiness, of the pre-shock interstellar medium. As might be expected, the spiral shock forms dense clouds while dissipating kinetic energy, producing regions that are locally gravitationally bound and collapse to form stars. But the effect of the clumpiness of gas as it passes through the shock is to generate chaotic internal motions in the gas. The kinematics of these motions are found to agree with the observed velocity-dispersion/size relation found in star-forming regions. In contrast to the standard picture where continuously driven turbulence generates the density inhomogeneities in star-forming clouds, we find here that it is the clumpiness of the interstellar gas that produces the chaotic motions as it passes through the spiral shock and initiates the star formation process. The velocity dispersion can be understood as being due to the random mass loading of clumps as they converge in the spiral shock. Within these clouds both the timescale for the decay of these motions, and the timescale for forming stars, are comparable to the clouds’ dynamical lifetimes. In this model there is no need for any internal or external continuous driving mechanism for the ’turbulence’. In addition, the coupling of the clouds’ internal kinematics to their externally triggered formation removes the need for the clouds to be self-gravitating. Indeed, while clearly some parts of the clouds are self-gravitating and able to form stars, most of the molecular material remains gravitationally unbound. This can provide a simple explanation for the low efficiency of star formation.
American Journal of Epidemiology Original Contribution Serum Levels of Perfluorooctanoic Acid and Perfluorooctane Sulfonate and Pregnancy Outcome

The authors examined the association of serum perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) with self-reported pregnancy outcome in Mid-Ohio Valley residents (2000–2006) highly exposed to PFOA. Data on 1,845 pregnancies within the 5 years preceding exposure measurement were analyzed for PFOA, and data on 5,262 pregnancies were analyzed for PFOS. Generalized estimating equations were used to calculate adjusted odds ratios and 95% confidence intervals. Neither PFOA nor PFOS showed any association with miscarriage or preterm birth. Preeclampsia was weakly associated with PFOA (adjusted odds ratio ¼ 1.3, 95% confidence interval: 0.9, 1.9) and PFOS (adjusted odds ratio ¼ 1.3, 95% confidence interval: 1.1, 1.7) exposures above the median. PFOA was not associated with an increase in low birth weight, but PFOS showed an increased risk above the median (adjusted odds ratio ¼ 1.5, 95% confidence interval: 1.1, 1.9) and a dose-response gradient. Birth defects were weakly associated with PFOA exposures above the 90th percentile (adjusted odds ratio ¼ 1.7, 95% confidence interval: 0.8, 3.6). This study identified modest associations of PFOA with preeclampsia and birth defects and of PFOS with preeclampsia and low birth weight, but associations were small, limited in precision, and based solely on self-reported health outcomes. Perfluorooctanoic acid (PFOA) is a synthetic chemical that has been used in the manufacture of fluoropolymers since the 1950s (1) and may also result from the breakdown of a related group of chemicals called fluorinated telomers (2). Fluoropolymers are used in nonstick cookware and clothing made from waterproof, breathable fabric (2). PFOA and another perfluorinated compound (PFC) with comparable industrial uses—perfluorooctane sulfonate (PFOS)—are persistent environmental pollutants that have been detected worldwide in both wildlife and humans, with higher exposure closer to urbanized and industrialized regions (3). In the general US population, PFOA and PFOS were detected in all serum samples from geometric mean values were measured at 5.2 ng/mL for PFOA and 30.4 ng/mL for PFOS (4). These values dropped to 3.9 ng/mL and 20.7 ng/ mL, respectively, in the 2003–2004 survey (5). PFOA and PFOS have been detected in maternal and umbilical cord blood (6–8) and breast milk (9–13). The serum elimination half-life is approximately 4 years for PFOA and 5 years for PFOS (14). Toxicology studies highlight the potential for these PFCs to affect fetal growth and development. A series of studies suggest that in utero exposure to PFCs is associated with a range of nonspecific adverse infant …
Gastroesophageal Reflux in Neurologically Impaired Children: What Are the Risk Factors?

Background/Aims Neurologically impaired patients frequently suffer from gastrointestinal tract problems, such as gastroesophageal reflux disease (GERD). In this study, we aimed to define the risk factors for GERD in neurologically impaired children. Methods From May 2006 to March 2014, 101 neurologically impaired children who received 24-hour esophageal pH monitoring at Severance Children’s Hospital were enrolled in the study. The esophageal pH finding and the clinical characteristics of the patients were analyzed. Results The reflux index was higher in patients with abnormal electroencephalography (EEG) results than in those with normal EEG results (p=0.027). Mitochondrial disease was associated with a higher reflux index than were epileptic disorders or cerebral palsy (p=0.009). Patient gender, feeding method, scoliosis, tracheostomy, and baclofen use did not lead to statistical differences in reflux index. Age of onset of neurological impairment was inversely correlated with DeMeester score and reflux index. Age at the time of examination, the duration of the disease, and the number of antiepileptic drugs were not correlated with GER severity. Conclusions Early-onset neurological impairment, abnormal EEG results, and mitochondrial disease are risk factors for severe GERD.
Two-dimensional spatiotemporal coding of linear acceleration in vestibular nuclei neurons

Response properties of vertical (VC) and horizontal (HC) canal/otolith- convergent vestibular nuclei neurons were studied in decerebrate rats during stimulation with sinusoidal linear accelerations (0.2–1.4 Hz) along different directions in the head horizontal plane. A novel characteristic of the majority of tested neurons was the nonzero response often elicited during stimulation along the “null” direction (i.e., the direction perpendicular to the maximum sensitivity vector, Smax). The tuning ratio (Smin gain/Smax gain), a measure of the two- dimensional spatial sensitivity, depended on stimulus frequency. For most vestibular nuclei neurons, the tuning ratio was small at the lowest stimulus frequencies and progressively increased with frequency. Specifically, HC neurons were characterized by a flat Smax gain and an approximately 10-fold increase of Smin gain per frequency decade. Thus, these neurons encode linear acceleration when stimulated along their maximum sensitivity direction, and the rate of change of linear acceleration (jerk) when stimulated along their minimum sensitivity direction. While the Smax vectors were distributed throughout the horizontal plane, the Smin vectors were concentrated mainly ipsilaterally with respect to head acceleration and clustered around the naso-occipital head axis. The properties of VC neurons were distinctly different from those of HC cells. The majority of VC cells showed decreasing Smax gains and small, relatively flat, Smin gains as a function of frequency. The Smax vectors were distributed ipsilaterally relative to the induced (apparent) head tilt. In type I anterior or posterior VC neurons, Smax vectors were clustered around the projection of the respective ipsilateral canal plane onto the horizontal head plane. These distinct spatial and temporal properties of HC and VC neurons during linear acceleration are compatible with the spatiotemporal organization of the horizontal and the vertical/torsional ocular responses, respectively, elicited in the rat during linear translation in the horizontal head plane. In addition, the data suggest a spatially and temporally specific and selective otolith/canal convergence. We propose that the central otolith system is organized in canal coordinates such that there is a close alignment between the plane of angular acceleration (canal) sensitivity and the plane of linear acceleration (otolith) sensitivity in otolith/canal- convergent vestibular nuclei neurons.
The Nature of Student Thinking and Its Implications for the Use of Learning Progressions to Inform Classroom Instruction

Underlying much of the work on learning progressions (LPs) is a strong though often tacit assumption that student thinking is theory-like and context-independent. In this work-in-progress, we use both theoretical perspectives on the nature of novices’ knowledge and empirical evidence of the context-dependent variability of students’ reasoning in physics to question this assumption and to argue that characterizing students in terms of LP “levels” inadequately captures their understanding of force and motion. We then analyze one teacher’s use of LP-based data to reason about student thinking and instructional responses. While the teacher reasoned fluidly using LP levels, he more frequently used finer-grained knowledge elements and contextual factors to interpret student thinking; and these finer-grained interpretations led to more actionable instructional implications. Thus, while recognizing LPs as models (imperfect representations) of student thinking, we argue that their assumption of “levels” of student understanding may limit their utility for classroom decision-making.
Robust Dissipativity of Interval Uncertain Linear Systems

In this paper we are concerned with the problem of robust dissipativity of linear systems with parameters affected by box uncertainty; our major goal is to evaluate the largest uncertainty level for which all perturbed instances share a common dissipativity certificate. While it is NP-hard to compute this quantity exactly, we demonstrate that under favorable circumstances one can build an O(1)-tight lower bound of this "intractable" quantity by solving an explicit semidefinite program of the size polynomial in the size of the system. We consider a number of applications, including the robust versions of the problems of extracting nearly optimal available storage, providing nearly optimal required supply, Lyapunov stability analysis, and linear-quadratic control.
On the thermodynamic stability of a charged arginine side chain in a transmembrane helix

Biological membranes consist of bilayer arrangements of lipids forming a hydrophobic core that presents a physical barrier to all polar and charged molecules. This long-held notion has recently been challenged by biological translocon-based experiments that report small apparent free energies to insert charged side chains near the center of a transmembrane (TM) helix. We have carried out fully atomistic simulations to provide the free-energy profile for moving a TM helix containing a protonated Arg side chain across a lipid bilayer. Our results reveal the fundamental thermodynamics governing the stability of charged side chains in membranes and the microscopic interactions involved. Despite local membrane deformations, where large amounts of water and lipid head groups are pulled into the bilayer to interact with Arg, the free-energy barrier is 17 kcal/mol. We provide a rationale for the differences in our microscopic free energies and cell biological experiments using free-energy calculations that indicate that a protonated Arg at the central residue of a TM helix of the Leader peptidase might reside close to the interface and not at the membrane center. Our findings have implications for the gating mechanisms of voltage-gated ion channels, suggesting that movements of protonated Arg residues through the membrane will be prohibited.
Water column biogeochemistry of oxygen minimum zones in the eastern tropical North Atlantic and eastern tropical South Pacific oceans

Abstract. Recent modeling results suggest that oceanic oxygen levels will decrease significantly over the next decades to centuries in response to climate change and altered ocean circulation. Hence, the future ocean may experience major shifts in nutrient cycling triggered by the expansion and intensification of tropical oxygen minimum zones (OMZs), which are connected to the most productive upwelling systems in the ocean. There are numerous feedbacks among oxygen concentrations, nutrient cycling and biological productivity; however, existing knowledge is insufficient to understand physical, chemical and biological interactions in order to adequately assess past and potential future changes. In the following, we summarize one decade of research performed in the framework of the Collaborative Research Center 754 (SFB754) focusing on climate–biogeochemistry interactions in tropical OMZs. We investigated the influence of low environmental oxygen conditions on biogeochemical cycles, organic matter formation and remineralization, greenhouse gas production and the ecology in OMZ regions of the eastern tropical South Pacific compared to the weaker OMZ of the eastern tropical North Atlantic. Based on our findings, a coupling of primary production and organic matter export via the nitrogen cycle is proposed, which may, however, be impacted by several additional factors, e.g., micronutrients, particles acting as microniches, vertical and horizontal transport of organic material and the role of zooplankton and viruses therein.