Miracle-dz/UniFAR-FTUs huggingface dataset:
From economies of density and network scale to multioutput economies of scale and scope: a synthesis

For more than twenty years transport industry structure in general, and that of the airline industry in particular, has been analyzed with the help of indices like Returns to Density (RTD) and Returns to Scale with variable network size (RTS). Along this period, caveats, corrections and improvements to calculate these measures have arisen. Nevertheless, both RTD and RTS have been established as the textbook indices to study, from a cost perspective, important issues like merging, optimal network size and shape, and the scope for competition. The objective of this paper is to organize this discussion, offering a synthesis of many years of research, and to prescribe what is, in our view, the best way to go about the empirical analysis of industry structure. We conclude that recently suggested methods to calculate i)(corrected) economies of density, ii) the multiproduct degree of economies of scale and iii) the degree of economies of scope, should be used. Both RTD and RTS are defined as scale concepts and calculated as the inverse of the sum of certain product elasticities of costs. Regarding RTD, the basic idea is to analyze the effect on costs of product growth holding network size constant. Yet, in some cases, some authors introduce (many times implicitly) a second condition, namely holding the route structure constant. This introduces ambiguities about what the index is really capturing. On the other hand, RTS is aimed at analyzing costs as both output and the network grow. Both concepts are usually applied within the context of product specified as a vector of aggregate descriptors, but no general consensus about what descriptors should be used has been reached. This generates a second source of ambiguity regarding the use of these indices, as different authors consider different aggregate elasticities. In our paper, we note that the aggregate descriptors are a function of the many transport flows that firms move from many origins to many destinations. We then argue analytically that, in transport, the multiproduct degree of returns to scale gives raise to two different indices, one of which correspond to an improved version of what is currently understood as RTD, while the second -though informative- has not been identified yet. Finally, we sustain that the calculation of economies of spatial scope should replace the calculation of RTS. For the covering abstract see ITRD E135582.
CEO Hedging Opportunities and the Weighting of Performance Measures in Compensation Contracts

Ideally, managerial ownership and short-sale constraints make managers bear firm-specific risk, leading them to prioritize shareholder interests. However, corporate managers can easily hedge their ownership positions, thereby avoiding firm-specific risk. In the context of managerial hedging, we examine whether corporate boards take advantage of accounting-based performance measures, which can be observed ex post, to develop efficient incentive schemes ex ante that will induce managers to take desired actions. We first investigate the effect of CEO hedging opportunities or hedging cost and performance measures on compensation, considering the relative weighting of accountingand stock-based performance measures. We find that when managerial hedging cost is low, compensation is more sensitive to accounting-based than stock-based performance measures. Additionally, the effect of the interaction between managerial hedging opportunities and accounting-based performance measures on compensation increases with managerial hedging needs (represented by managerial ownership and firm-specific risk). Overall, our study relies on the contract theory to provide evidence that given managerial hedging, accounting information plays an important role in compensation design.
Ascorbate biosynthesis in Arabidopsis cell suspension culture.

The biosynthesis of L-ascorbic acid (L-AA) in an Arabidopsis (L.) Heynh. cell suspension culture was studied by quantifying the effects of incubation with a range of potential biosynthetic precursors, analogs, and inhibitors on the intracellular levels of reduced and oxidized forms of L-AA. Our results support the recently published biosynthetic pathway of L-AA from L-galactose (G.L. Wheeler, M.A. Jones, N. Smirnoff [1998] Nature 393: 365-369), but suggest that Arabidopsis cell suspension culture simultaneously contains two other routes leading to L-AA. The possible physiological significance of these alternate routes is discussed.
The 2-phase case-control design: an efficient way to use expert-time.

OBJECTIVES The objective of this paper is to show the benefits of using a 2-phase case-control (2PCC) design in identifying dose-response relationships between cumulative occupational exposure as assessed by experts and lung cancer incidence in an actual study. METHODS A population-based case-control study including 246 cases and 531 controls was conducted in an area with high lung cancer rates in Northeast France. Detailed occupational and personal risk factors were obtained in face-to-face interviews. Cumulative expert-based exposure scores were obtained from a subset of 215 cases and 269 controls stratified on smoking and a prior algorithmic exposure score for asbestos, crystalline silica, and polycyclic aromatic hydrocarbons (PAH) in the framework of a 2PCC design. This subset deliberately under-sampled large strata among controls but not among cases. Logistic regression models adapted to 2PCC studies were applied and corresponding computations of attributable fractions and their confidence intervals developed. RESULTS Based on this 2PCC design, statistically significant dose-response relationships were obtained for asbestos, crystalline silica, PAH, and diesel motor exhaust. Simulations within this study showed that 2PCC studies were always more powerful than random samples. CONCLUSION The 2PCC design may be the design of choice when resources allow only a limited number of subjects with a full expert-based exposure assessment.
Importance of Anatomical Landmarks on Axillary Neurovascular Territories for Surgery

The anatomy of axillary neurovascular architechture is very important for neurosurgeon, plastic and cardiovascular surgeons, and also radiologists to aid in diagnosis, treatment and planning surgical procedure. Walsh and Willar were firstly described brachial plexus (BP) anatomy in details from 1877 (Akboru et al, 2010). After rapid development of microsurgical approaches, variations and injuries of the plexus, their diagnosis and treatment were searched by many authors. Inspite of the belief that BP malformations together with the vascular malformations, variations of BP may be encountered without arterial or venous abnormalities. Variations of axillary vessels and BP are of importance for clinicians either the diagnostic interventions or the surgical applications. The knowledge of the anatomical variations of the vascular and BP can help to give explanation when encountering incomprehensible and extraordinary clinical signs. While planning flap surgery, the surface landmarks on axillary skin area and variations of the neurovasculatures are of significance for surgeons. Iatrogenic BP injuries have been reported during infraclavicular and transaxillary biopsy, general anesthesia and resection of space occupying lesions in axillary region. Cause of iatrogenic injuries include needle trauma and haematoma during central venous catheterization due to neural ischaemia may be encountered. The vein catheterization is more likely with multiple needle passes and generally affects BP (Zhang et al, 2011).
The Signature: A Never-Sent Letter to the Editors of Neurology, Updated With Commentary and Guidelines for the Future

A recent paper in Neurology by Annette Schrag et al. [1,2] with an accompanying editorial by D.L. Gilbert and R. Kurlan [2] caught my attention as being a perfect example of what modern medicine is doing, right and wrong in its current policies regarding the statistical treatment of patient data. Schrag et al. did a magnificent job surveying a database of 678,862 UK patients to search for associations between streptococcal infection and certain neuropsychiatric disorders including tics, Tourette syndrome and obsessive-compulsive disorder collectively termed PANDAS (Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcus B infection; Swedo et al. [3]). Schrag et al. [1] used conditional logistic regression to identify controls matched for age and sex and wound up with 254 cases and 2,211 controls. They sliced and diced this data for such other variables as antibiotic treatment and ethnicity, but in the end could not confirm a statistically significant association between streptococcal infection and the PANDAS [1].
Breast lesion localization: a freehand, interactive MR imaging-guided technique.

PURPOSE To evaluate interactive magnetic resonance (MR) imaging-guided preoperative needle localization and hookwire placement in the noncompressed breast in patients in the prone position. MATERIALS AND METHODS Nineteen MR imaging-guided breast lesion localization procedures were performed in 17 patients aged 38-70 years (mean age, 48 years) by using an open-platform breast coil in either a 1.5-T, closed-bore imager (n = 14) or a 0.5-T, open-bore imager (n = 5). Rapid imaging (fast spin-echo, water-selective fast spin-echo, or water-specific three-point Dixon gradient-echo) was alternated with freehand manipulation of an MR-compatible needle to achieve accurate needle placement. RESULTS Up to three manipulations of the needle were required during an average of 9 minutes to reach the target lesion. MR imaging findings confirmed the final needle position within 9 mm of the target in all cases. The accuracy of 10 localizations was independently corroborated either at mammography or at ultrasonography. Nine lesions were visible on MR images only. CONCLUSION Interactive MR imaging-guided, freehand needle localization is simple, accurate, and requires no special stereotactic equipment. Lesions throughout the breast, including those in the anterior part of the breast and those near the chest wall, which can be inaccessible with standard grid or compression-plate techniques, can be localized. A variety of needle trajectories in addition to the horizontal path are possible, including circumareolar approaches and tangential needle paths designed to avoid puncture of implants.
Clinical Implications The long-term clinical performance of various ceramic systems placed by multiple practitioners in a group practice provides clinically based evidence of complications and the long-term management of these restorations

Results. Fifty-nine patients (41 women, 18 men) with 226 single teeth and implants restored with single ceramic crowns were identified. The mean duration from insertion date to study examination date was 6.1 years. Thirteen restorations (6%) were replaced at a mean 3.3 years after insertion date (range, 0.1-6.1 years). Estimated replacement-free survival rates (95% confidence interval [CI]; number of teeth/implants still at risk) at 5 years after insertion datewere 95.1% (95%CI, 92.2-98.1; 153) and at 10 years were 92.8% (95% CI, 89.1-96.8; 8). The most common reason for replacement was fracture to the core of posterior layered ceramic crowns. Themost commonly used luting agent was resin-modified ionomer cement.Most restorations exhibited clinically acceptable marginal integrity, shade, no caries recurrence, and no periapical pathology.
The Vocal Cord Polyp

A variety of clinical synonyms exists for the vocal cord polyp. These include teacher's, singer's, preacher's and screamer's nodes, chorditis tuberosa and nodosa. As will be shown, polyps, nodes and polypoidal degenerations are histologically identical non-neoplastic swellings of the membranous cord. Polyps by definition are pedunculated, nodes sessile and polypoidal degenerations diffuse. There is no justification whatsoever
Zirconia versus Co-Cr Femoral Heads in Total Hip Arthroplasty: Early Assessment of Wear

Polyethylene wear and associated osteolysis are major limitations to the long-term success of total hip arthroplasty. In vitro laboratory studies suggest polyethylene wear in THA may be substantially reduced with ceramic femoral heads. We evaluated the potential value of zirconia ceramic on conventional polyethylene as an “alternative bearing” for total hip arthroplasty in a prospective, randomized clinical trial in comparison with femoral heads made of Co-Cr-Mo. Patients were evaluated with standardized clinical outcome instruments, and measurement of head penetration was performed with computerized wear measurement software. Study enrollment was halted because of a recall of the zirconia heads. At that time, 30 total hip arthroplasties with Co-Cr-Mo heads and 30 total hip arthroplasties with zirconia heads had been performed. Mean followup was similar for both groups (Co-Cr-Mo = 51.7 months; zirconia = 51.2 months). The mean annual head penetration rate was low and similar for both groups (Co-Cr-Mo = 0.060 mm/year; and zirconia = 0.055 mm/year). In view of the recently reported potential for zirconia ceramics to undergo monoclinic phase transformation in vivo, with resultant increased fracture risk and degradation of wear properties, we do not recommend use of zirconia femoral heads as an “alternative bearing” for total hip arthroplasty.Level of Evidence: Level II, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.
External validation of the DASH prediction rule: a retrospective cohort study

Essentials Predicting recurrences may guide therapy after unprovoked venous thromboembolism (VTE). We evaluated the DASH score in 827 patients with unprovoked VTE to verify prediction accuracy. A DASH score ≤ 1 had a cumulative recurrence risk at 1 year of 3.6%, as predicted by the model. The DASH score performed better in younger (< 65 years old) subjects.
The Ponzo illusion affects grip-force but not grip-aperture scaling during prehension movements.

Contextual cues such as linear perspective and relative size can exert a powerful effect on the perception of objects. This fact is demonstrated by the illusory effects that can be induced by such cues (e.g., the Ponzo railway track and Titchener circles illusions). Several recent studies have reported, however, that visual illusions based on such cues have little or no influence on the visuomotor mechanisms used to guide hand action. Furthermore, evidence of this sort has been cited in support of a distinction between visual perception and the visual control of action. In the current study, the authors investigated the effect of the Ponzo visual illusion on the control of hand action, specifically, the scaling of grip force and grip aperture during prehension movements. The results demonstrate that grip force scaling is significantly influenced by the Ponzo visual illusion, whereas the scaling of grip aperture is unaffected by the illusion.
An in situ crosslinked compression coat comprised of pectin and calcium chloride for colon-specific delivery of indomethacin

Abstract The use of pectin for colon-specific drug delivery has been extensively investigated; however, when used alone, pectin is often compromised due to its high solubility. This study explored the feasibility of using an in situ compression-coated crosslinking system, composed of pectin and calcium chloride, for colon-specific drug delivery. A pectin/calcium chloride (P/Ca) coating was compressed onto a core tablet. The colon specificity of the compression-coated tablet was verified by dissolution, pharmacokinetics and scintigraphy with 99mTc labeling. The in situ pectin and calcium chloride gel slowed the release of indomethacin. The lag time varied between 3 h and 7 h depending on the amount of calcium chloride and the coating weight. Pectinase triggered the release of indomethacin from the compression-coated tablet, which was then accelerated by the calcium chloride in the coating layer. The compression-coated tablet had a prolonged tmax and apparent t1/2, as well as a decreased Cmax and AUC0–t, compared with the core tablet counterpart. Evaluation with γ-scintigraphy verified colon-specific delivery of the compression-coated tablet. In conclusion, the P/Ca in situ crosslinking system worked well for colon-specific drug delivery.
The ultrastructure of cultivable treponemes. 2. Treponema calligyrum, Treponema minutum and Treponema microdentium.

Treponema phagedenis, Treponema vincentii, and Treponema refringens were studied in the electron microscope by means of negative staining and sectioning techniques. The length and width of the cells were within the same limits for all three strains examined. Statistical analysis, however, demonstrated a difference in the wavelengths of the cells. Organisms of T. phagedenis and T. vincentii had blunt ends and possessed cell wall surface layers in which a regular substructure was only occasionally revealed, while cells of T. refringens had tapered ends and a distinctly structured cell wall surface layer. Generally, cells of the strains investigated had 4–6 flagella inserted at each end. Two bundles of flagella, one from each end of the cell, wound around the organism and overlapped in the middle of the cell. The flagella with their insertion organelles were identical for the three strains studied. Two bundles of cytoplasmic tubules were detected in the interior of the treponemes after treatment with either sodium deoxycholate or Myxobacter AL-1 protease 1. The two bundles of cytoplasmic tubules overlapped in the middle of the cell. The results of the present morphological study are compared with results obtained by other investigators studying other characteristics of these strains and it is concluded that the three strains studied belong to three different species.
Chelyabinsk Airburst, Damage Assessment, Meteorite Recovery, and Characterization

Deep Impact? On 15 February 2013, the Russian district of Chelyabinsk, with a population of more than 1 million, suffered the impact and atmospheric explosion of a 20-meter-wide asteroid—the largest impact on Earth by an asteroid since 1908. Popova et al. (p. 1069, published online 7 November; see the Perspective by Chapman) provide a comprehensive description of this event and of the body that caused it, including detailed information on the asteroid orbit and atmospheric trajectory, damage assessment, and meteorite recovery and characterization. A detailed study of a recent asteroid impact provides an opportunity to calibrate the damage caused by these rare events. [Also see Perspective by Chapman] The asteroid impact near the Russian city of Chelyabinsk on 15 February 2013 was the largest airburst on Earth since the 1908 Tunguska event, causing a natural disaster in an area with a population exceeding one million. Because it occurred in an era with modern consumer electronics, field sensors, and laboratory techniques, unprecedented measurements were made of the impact event and the meteoroid that caused it. Here, we document the account of what happened, as understood now, using comprehensive data obtained from astronomy, planetary science, geophysics, meteorology, meteoritics, and cosmochemistry and from social science surveys. A good understanding of the Chelyabinsk incident provides an opportunity to calibrate the event, with implications for the study of near-Earth objects and developing hazard mitigation strategies for planetary protection.
Best-of-five Contest: An Experiment on Gender Differences

Abstract Prior gender literature has focused on whether men and women differ in their willingness to enter competition. We conduct a laboratory study to examine, instead, gender differences while in competition. We analyze effort choices in a best-of-five probabilistic contest. The longer contest and the careful manipulation of the gender composition allow us to identify gender differences in competitiveness in an environment where success requires repeated interaction. We find that women exert significantly greater effort only when competing against other women, but for men the gender of the opponent is of no consequence. Our multi-battle structure also enables us to identify the psychological impact of immediate prior outcomes and the strategic impact of early round wins or losses, as well as their differential impact on genders. Across both genders, we find evidence supporting strategic momentum, but not psychological momentum. Finally, subjects who exhibit lower level of confidence and those who have higher utility of winning choose higher effort levels.
Learning through creating learning objects: experiences with a class project in a distributed systems course

An alternative to a final programming project in a Distributed Systems course is presented. The alternative project, which can easily be adapted to several Computer Science courses, consists in assigning different course topics to pairs of students, for them to develop an interactive learning object to help their classmates and future students of the class understand the subject. The project was well received by the students of the class, and their comments and survey results suggest that their knowledge on the subject improved both by using the learning objects of their peers and by working in developing their own.
The Predictive Impact of Biological and Sociocultural Factors on Executive Processing: The Role of Age, Education, and Frequency of Reading and Writing Habits

Although the impact of education and age on executive functions (EF) has been widely studied, the influence of daily cognitive stimulation on EF has not been sufficiently investigated. Therefore, the aim of the present study was to evaluate whether the age, education, and frequency of reading and writing habits (FRWH) of healthy adults could predict their performance on measures of inhibition and cognitive flexibility. Inhibition speed, inhibitory control, and set shifting were assessed using speed, accuracy, and discrepancy scores on the Trail-Making Test (TMT) and Hayling Test. Demographic characteristics and the FRWH were assessed using specialized questionnaires. Regression analyses showed that age and the FRWH predicted speed and accuracy on the TMT. The FRWH predicted both speed and accuracy on the Hayling Test, for which speed and accuracy scores were also partly explained by age and education, respectively. Surprisingly, only the FRWH was associated with Hayling Test discrepancy scores, considered one of the purest EF measures. This highlights the importance of regular cognitive stimulation over the number of years of formal education on EF tasks. Further studies are required to investigate the role of the FRWH so as to better comprehend its relationship with EF and general cognition.