LLukas22/scidocs huggingface dataset:
Pseudo-Mathematics and Financial Charlatanism: The Effects of Backtest Overfitting on Out-of-Sample Performance

Recent computational advances allow investment managers to search for profitable investment strategies. In many instances, that search involves a pseudo-mathematical argument, which is spuriously validated through a simulation of its historical performance (also called backtest). We prove that high performance is easily achievable after backtesting a relatively small number of alternative strategy configurations, a practice we denote “backtest overfitting.” The higher the number of configurations tried, the greater is the probability that the backtest is overfit. Because financial analysts rarely report the number of configurations tried for a given backtest, investors cannot evaluate the degree of overfitting in most investment proposals. The implication is that investors can be easily misled into allocating capital to strategies that appear to be mathematically sound and empirically supported by an outstanding backtest. This practice is particularly pernicious, because due to the nature of financial time series, backtest overfitting has a detrimental effect on the future strategy’s performance.
The pleasing end result after DIEP flap breast reconstruction: a review of additional operations.

BACKGROUND
Breast reconstruction with deep inferior epigastric perforator (DIEP) flaps is typically a three-stage procedure, but additional operations may be required to deal with complications or to improve the aesthetic result. The purpose of this study was to evaluate the total number of operations needed after DIEP flap breast reconstruction to achieve a satisfactory end result for the patient.


PATIENTS AND METHODS
From December 2002 to October 2006, 99 DIEP flap breast reconstructions obtained an end result in 72 patients. Data were collected in a structured database. Additional operations and complications were evaluated for the entire group. A study-specific questionnaire was used to evaluate patient satisfaction.


RESULTS
The mean number of additional operations was 1.4 per patient. Patients with complications required more operations than patients without complications. Women who chose nipple reconstruction were younger than women who did not and were more likely to have had a primary or secondary than a tertiary reconstruction. The number of additional aesthetic operations was neither related to the occurrence of complications during the initial reconstruction, nor to patient satisfaction. Overall, patients were very satisfied with the end result.


CONCLUSIONS
Completion of DIEP flap breast reconstruction involved the initial reconstruction and an average of 1.4 additional operations. Patients were generally very satisfied with the end result.
Effects of sleep deprivation on procedural errors.

In a large sample (N = 234), we tested effects of 24-hr of sleep deprivation on error rates in a procedural task that requires memory maintenance of task-relevant information. In the evening, participants completed the task under double-blind conditions and then either stayed awake in the lab overnight or slept at home. In the morning, participants completed the task again. Sleep-deprived participants were more likely to suffer a general breakdown in ability (or willingness) to meet a modest accuracy criterion they had met the night before. Among sleep-deprived participants who could still perform the task, error rates were elevated, and errors reflecting memory failures increased with time-on-task. The results suggest that sleep-deprived individuals should not perform procedural tasks associated with interruptions and costly errors-or, if they must, they should perform such tasks only for short periods. (PsycINFO Database Record (c) 2018 APA, all rights reserved).
Designing functionally graded materials with superior load-bearing properties.

Ceramic prostheses often fail from fracture and wear. We hypothesize that these failures may be substantially mitigated by an appropriate grading of elastic modulus at the ceramic surface. In this study, we elucidate the effect of elastic modulus profile on the flexural damage resistance of functionally graded materials (FGMs), providing theoretical guidelines for designing FGMs with superior load-bearing property. The Young's modulus of the graded structure is assumed to vary in a power-law relation with a scaling exponent n; this is in accordance with experimental observations from our laboratory and elsewhere. Based on the theory for bending of graded beams, we examine the effect of n value and bulk-to-surface modulus ratio (E(b)/E(s)) on stress distribution through the graded layer. Theory predicts that a low exponent (0.15<n<0.5), coupled with a relatively small modulus ratio (3<E(b)/E(s)<6), is most desirable for reducing the maximum stress and transferring it into the interior, while keeping the surface stress low. Experimentally, we demonstrate that elastically graded materials with various n values and E(b)/E(s) ratios can be fabricated by infiltrating alumina and zirconia with a low-modulus glass. Flexural tests show that graded alumina and zirconia with suitable values of these parameters exhibit superior load-bearing capacity, 20-50% higher than their homogeneous counterparts. Improving load-bearing capacity of ceramic materials could have broad impacts on biomedical, civil, structural, and an array of other engineering applications.
Effect of Waon therapy on oxidative stress in chronic heart failure.

BACKGROUND
A previous report by our team showed that Waon therapy, using a far infrared-ray dry sauna at 60°C, improves cardiac and vascular function in patients with chronic heart failure (CHF). The purpose of the present study was to clarify the effect of Waon therapy on oxidative stress in CHF patients and investigate its mechanism by animal experiments.


METHODS AND RESULTS
Forty patients with CHF were divided into control (n=20) and Waon therapy (n=20) groups. All patients received standard optimal medications for CHF. Waon therapy group was treated with Waon therapy daily for 4 weeks. After 4 weeks of Waon therapy, concentrations of hydroperoxide and brain natriuretic peptide (BNP) decreased significantly (hydroperoxide, 422±116 to 327±88U.CARR, P<0.001; BNP, 402±221 to 225±137pg/ml, P<0.001), and the nitric oxide metabolites increased (71.2±35.4 to 92.0±40.5mmol/L, P<0.05). In contrast, none of these variables changed over the 4-week interval in the control group. Furthermore, animal experiments were performed using TO-2 cardiomyopathic hamsters. On immunohistochemistry, cardiac expression of 4-hydroxy-2-nonenal, a marker of oxidative stress, was decreased in the 4-week Waon therapy compared to untreated hamsters. On Western blotting, cardiac expressions of heat shock protein (HSP) 27, manganese superoxide dismutase and HSP32, which reduce oxidative stress, were significantly upregulated in the 4-week Waon therapy compared to untreated hamsters.


CONCLUSIONS
Waon therapy decreases oxidative stress in patients and hamsters with heart failure.
Predictors of response and remission in a large cohort of rheumatoid arthritis patients treated with tocilizumab in clinical practice.

OBJECTIVE
The objective of this study was to identify predictors of response and remission to tocilizumab (TCZ) in RA patients seen in daily routine clinical practice.


METHODS
The efficacy of TCZ was evaluated after 12 and 24 weeks of treatment by the European League Against Rheumatism (EULAR) response criteria. Regression analysis was performed to study the association between remission or EULAR response and the following characteristics: gender, age, current smokers, prior cardiovascular disease (CVD), 28-joint disease activity score (DAS28), CRP, RF or ACPA positivity, combination therapy with DMARDs and TCZ as the first biological therapy or after failure of at least one biological therapy.


RESULTS
In total, 204 patients were included with a mean DAS28 score of 5.14. EULAR response and remission were obtained in 86.1% and 40% of patients, respectively, at week 24. In multiple regression analysis, a high baseline CRP level [odds ratio (OR) 4.454 (95% CI 1.446, 13.726)] was significantly associated with EULAR response at week 24 and, inversely, age >55 years [OR 0.285 (95% CI 0.086, 0.950)] and prior CVD [OR 0.305 (95% CI 0.113, 0.825)] were significantly associated with lower EULAR response at week 24. Older age was also associated with less remission at week 24 [OR 0.948 (95% CI 0.920, 0.978)]. No additional effectiveness was found when TCZ was used in combination with a DMARD or when patients were naive to biological agents.


CONCLUSION
In daily practice we identified three predictors of a better response for TCZ therapy in RA: a younger age, a high baseline CRP level and no history of CVD.
Robust estimation of protein expression ratios with lysate microarray technology

MOTIVATION
The protein lysate microarray is a developing proteomic technology for measuring protein expression levels in a large number of biological samples simultaneously. A challenge for accurate quantification is the relatively narrow dynamic range associated with the commonly used chromogenic signal detection system. To facilitate accurate measurement of the relative expression levels, each sample is serially diluted and each diluted version is spotted on a nitrocellulose-coated slide in triplicate. Thus, each sample yields multiple measurements in different dynamic ranges of the detection system. This study aims to develop suitable algorithms that yield accurate representations of the relative expression levels in different samples from multiple data points.


RESULTS
We evaluated two algorithms for estimating relative protein expression in different samples on the lysate microarray by means of a cross-validation procedure. For this purpose as well as for quality control we designed a 1440-spot lysate microarray containing 80 identical samples of purified bovine serum albumin, printed in triplicate with six 2-fold dilutions. Our analysis showed that the algorithm based on a robust least squares estimator provided the most accurate quantification of the protein lysate microarray data. We also demonstrated our methods by estimating relative expression levels of p53 and p21 in either p53(+/+) or p53(-/-) HCT116 colon cancer cells after two drug treatments and their combinations on another lysate microarray.


AVAILABILITY
http://www.cs.tut.fi/~mirceanc/lysate_array_bioinformatics.htm
Nutrients and antinutrients in cowpea and horse gram flours in comparison to chickpea flour: Evaluation of their flour functionality

The nutrient composition, antinutritional factors and flour functionality of cowpea and horse gram flours were evaluated in comparison to chickpea flour characteristics. Protein content of these flours was in the range of 22.5 24.1%. Fat content was highest in chickpea (4.8%) and lowest in horse gram (1.4%). Resistant starch and phytic acid were significantly higher in cowpea flour. Compared to chickpea and cowpea, horse gram has more carbohydrate, dietary fibre, polyphenols and trypsin inhibitor activity and less oligosaccharides. Horse gram and chickpea flours had the highest water and oil absorption capacities with values of 148.1% and 109.3%, respectively. Although emulsion activity (58.1%) and stability (52.0%) were superior in horse gram, foaming capacity and foam stability were significantly higher in chickpea and cowpea flours, respectively. These results suggest the potential utility of cowpea and horse gram flours as substitutes for chickpea flour in some food products formulations. 2011 Elsevier Ltd. All rights reserved.
Blindness and vision impairment in a rural south Indian population: the Aravind Comprehensive Eye Survey.

OBJECTIVE
To determine the prevalence of blindness and vision impairment in a rural population of southern India.


DESIGN
A population-based cross-sectional study.


PARTICIPANTS
A total of 17200 subjects aged 6 years or older, including 5150 subjects aged 40 years or older from 50 clusters representative of three southern districts of Tamil Nadu in southern India.


METHODS
All participants had preliminary screenings consisting of vision using a LogMAR illiterate E chart and anterior segment hand light examinations at the village level. Subjects aged 40 years or older were offered comprehensive eye examinations at the base hospital, including visual acuity using LogMAR illiterate E charts and refraction, slit-lamp biomicroscopy, gonioscopy, applanation tonometry, dilated fundus examinations, and automated Humphrey central 24-2 full threshold perimetry; subjects younger than 40 years of age who had any signs or symptoms of ocular disease were also offered comparable examinations at the base hospital.


MAIN OUTCOME MEASURES
Visual impairment was defined as best-corrected visual acuity <6/18, and blindness was defined using both Indian (<6/60) and World Health Organization (<3/60) definitions.


RESULTS
Comprehensive examinations at the base hospital were performed on 5150 (96.5%) of 5337 persons 40 years of age or older. Among those 40 years of age and older, presenting visual acuity at the <3/60 level was present in 4.3% (95% confidence interval [CI]: 3.8, 4.9) and 11.4% (95% CI: 10.6, 12.3) at the <6/60 level. After best correction, the corresponding figures were 1.0% (95% CI: 0.79, 1.2) and 2.1% (95% CI: 1.7, 2.5). Over 70% of subjects improved their vision by at least one line, and nearly a third by three lines after refraction. Age-related cataract was the most common potentially reversible blinding disorder (72.0%) among eyes presenting with blindness.


CONCLUSIONS
Blindness and vision impairment remain major public health problems in India that need to be addressed. Cataracts and refractive errors remain the major reversible causes for the burden of vision impairment in this rural population.
Pearson’s correlation coefficient

Researchers investigated the relation between the number of involuntary admissions (detentions) for mental disorders a year under the Mental Health Act 1983 and the number of NHS psychiatric beds each year in England. They used hospital episode statistics from 1996 to 2006 in a retrospective analysis. For each year they obtained the number of available NHS psychiatric beds—defined as those beds for patients with mental disorders or learning disabilities—and the number of involuntary admissions for mental disorders in NHS hospital and private facilities combined. 1
Discrete unbounded sets in a finite dimensional space and beyond

Abstract Discrete infinite sets in a finite dimensional space, i.e., infinite sets without finite limit points appear in various branches of analysis (zero and pole sets of meromorphic functions, various models in the mathematical theory of quasicrystals, and so on). Here we introduce some notions and present some new theorems connected with such sets.
The meaningful identity: A longitudinal look at the interplay between identity and meaning in life in adolescence.

Identity formation in adolescence is closely linked to searching for and acquiring meaning in one's life. To date little is known about the manner in which these 2 constructs may be related in this developmental stage. In order to shed more light on their longitudinal links, we conducted a 3-wave longitudinal study, investigating how identity processes and meaning in life dimensions are interconnected across time, testing the moderating effects of gender and age. Participants were 1,062 adolescents (59.4% female), who filled in measures of identity and meaning in life at 3 measurement waves during 1 school year. Cross-lagged models highlighted positive reciprocal associations between (a) commitment processes and presence of meaning and (b) exploration processes and search for meaning. These results were not moderated by adolescents' gender or age. Strong identification with present commitments and reduced ruminative exploration helped adolescents in having a clear sense of meaning in their lives. We also highlighted the dual nature of search for meaning. This dimension was sustained by exploration in breadth and ruminative exploration, and it positively predicted all exploration processes. We clarified the potential for a strong sense of meaning to support identity commitments and that the process of seeking life meaning sustains identity exploration across time. (PsycINFO Database Record
Radial extracorporeal shock wave therapy (rESWT) in the treatment of spasticity in cerebral palsy: a randomized, placebo-controlled clinical trial.

AIM
The aim of this study was to evaluate the efficacy and safety of radial extracorporeal shock wave therapy (rESWT) in the treatment of spasticity in patients with cerebral palsy.


METHODS
Fifteen patients with spastic cerebral palsy, 12 men and 3 women, aged 10-46 years (mean age 31). The 15 patients presented 40 spastic muscles that were divided in three groups using a computerized random-number generator. The first group, received rESWT in spastic muscle. The second group received rESWT in spastic muscle + rESWT in antagonist muscle. The third group received placebo. Range of motion and Ashworth Scale were performed. This study is a randomized, placebo-controlled clinical trial. The patients were treated in 3 sessions at intervals of one week.


RESULTS
There are significant differences between groups treated with rESWT and group placebo. A significant decrease in the Ashworth Scale, an increase in the range of motion, were observed in all patients that were treated with rESWT. Positive results were maintained for at least 2 months after treatment.


INTERPRETATION
The treatment with rESWT is more effective than placebo in decreasing spasticity of patients with CP.
Real-world lessons from the implementation of a depression screening protocol in acute myocardial infarction patients: implications for the American Heart Association depression screening advisory.

BACKGROUND
The American Heart Association (AHA) statement has recommended routine screening for depression in coronary artery disease with a 2-stage implementation of the Patient Health Questionnaire (PHQ). Because there is little evidence on feasibility, accuracy, and impact of such a program on depression recognition in coronary patients, the AHA recommendation has met substantial debate and criticism.


METHODS AND RESULTS
Before the AHA statement was released, the Mid America Heart and Vascular Institute (MAHVI) had implemented a depression screening protocol for patients with acute myocardial infarction that was virtually identical to the AHA recommendations. To (1) evaluate this MAHVI quality improvement initiative, (2) compare MAHVI depression recognition rates with those of other hospitals, and (3) examine health care providers' implementation feedback, we compared the results of the MAHVI screening program with data from a parallel prospective acute myocardial infarction registry and interviewed MAHVI providers. Depressive symptoms (PHQ-2, PHQ-9) were assessed among 503 MAHVI acute myocardial infarction patients and compared with concurrent depression assessments among 3533 patients at 23 US centers without a screening protocol. A qualitative summary of providers' suggestions for improvement was also generated. A total of 135 (26.8%) eligible MAHVI patients did not get screened. Among screened patients, 90.9% depressed (PHQ-9 ≥10) patients were recognized. The agreement between the screening and registry data using the full PHQ-9 was 61.5% for positive cases (PHQ-9 ≥10) but only 35.6% for the PHQ-2 alone. Although MAHVI had a slightly higher overall depression recognition rate (38.3%) than other centers not using a depression screening protocol (31.5%), the difference was not statistically significant (P=0.31). Staff feedback suggested that a single-stage screening protocol with continuous feedback could improve compliance.


CONCLUSIONS
In this early effort to implement a depression screening protocol, a large proportion of patients did not get screened, and only a modest impact on depression recognition rates was realized. Simplifying the protocol by using the PHQ-9 alone and providing more support and feedback may improve the rates of depression detection and treatment.
Tweet, but verify: epistemic study of information verification on Twitter

While Twitter provides an unprecedented opportunity to learn about breaking news and current events as they happen, it often produces skepticism among users as not all the information is accurate but also hoaxes are sometimes spread. While avoiding the diffusion of hoaxes is a major concern during fast-paced events such as natural disasters, the study of how users trust and verify information from tweets in these contexts has received little attention so far. We survey users on credibility perceptions regarding witness pictures posted on Twitter related to Hurricane Sandy. By examining credibility perceptions on features suggested for information verification in the field of epistemology, we evaluate their accuracy in determining whether pictures were real or fake compared to professional evaluations performed by experts. Our study unveils insight about tweet presentation, as well as features that users should look at when assessing the veracity of tweets in the context of fast-paced events. Some of our main findings include that while author details not readily available on Twitter feeds should be emphasized in order to facilitate verification of tweets, showing multiple tweets corroborating a fact misleads users to trusting what actually is a hoax. We contrast some of the behavioral patterns found on tweets with literature in psychology research.
Intrarectal lidocaine is an effective treatment for abdominal pain associated with diarrhea-predominant irritable bowel syndrome.

UNLABELLED
Irritable bowel syndrome (IBS) is one of the most common disorders seen by gastroenterologists. Visceral hypersensitivity is now well recognized as a clinical marker for the disease. Intrarectal lidocaine has been previously shown to decrease pain report from rectal distension in patients with IBS without any significant serum lidocaine levels. We conducted a prospective, double-blind, crossover trial on 10 patients with IBS to evaluate the effects of 300 mg intrarectal lidocaine jelly on abdominal pain. Ten Caucasian premenopausal women who met the Rome II criteria for diarrhea-predominant IBS were recruited into the study. All of the patients that participated had intermittent left lower quadrant pain and diarrhea. Each patient participated in 2 sessions in which saline jelly (placebo) and lidocaine jelly was administered on a double-blind, crossover basis. Patients participated in these sessions at a time when their ongoing pain was at least 3 on a 0 to 10 visual analogue scale. In comparison to placebo saline jelly, lidocaine jelly significantly decreased abdominal pain (P < .02) for at least 4 hours. None of the patients experienced any side effects. Intrarectal lidocaine may be a potentially useful treatment for chronic abdominal pain in IBS.


PERSPECTIVE
The possible presence of abnormal sodium channels in the rectal and or colonic visceral afferents of patients with IBS might serve as a clue as to the effectiveness of rectal lidocaine. The dose of lidocaine used in this study may be of sufficient strength to normalize aberrant sodium channels that may be present in the colon of patients with IBS without affecting normal sodium channels of either IBS or control subjects.