Confounding Factors in Keystroke Dynamics

2015 ◽  
pp. 192-199
Author(s):  
Osvaldo Andrés Pérez-García
Keyword(s):  
Confounding Factors ◽  
Keystroke Dynamics

A Strategy for Analysing Multiple Risk Factors with Application to Cervical Pain Syndrome

1989 ◽  
Vol 28 (01) ◽  
pp. 14-19 ◽  
Author(s):  
J. F. Dartigues ◽  
Ph. Peytour ◽  
E. Puymirat ◽  
P. Henry ◽  
M. Gagnon ◽  
...  
Keyword(s):  
Risk Factors ◽  
Low Power ◽  
Head Trauma ◽  
Pain Syndrome ◽  
Psychological Status ◽  
Confounding Factors ◽  
Cervical Pain ◽  
Extreme Form ◽  
Explanatory Variables ◽  
Multiple Risk Factors

Abstract:When studying the possible effects of several factors in a given disease, two major problems arise: (1) confounding, and (2) multiplicity of tests. Frequently, in order to cope with the problem of confounding factors, models with multiple explanatory variables are used. However, the correlation structure of the variables may be such that the corresponding tests have low power: in its extreme form this situation is coined by the term “multicollinearity”. As the problem of multiplicity is still relevant in these models, the interpretation of results is, in most cases, very hazardous. We propose a strategy - based on a tree structure of the variables - which provides a guide to the interpretation and controls the risk of erroneously rejecting null hypotheses. The strategy was applied to a study of cervical pain syndrome involving 990 subjects and 17 variables. Age, sex, head trauma, posture at work and psychological status were all found to be important risk factors.

Establishing Standard Protocols for Bacterial Culture in Biological Research in Canisters (BRIC) Hardware

2020 ◽  
Vol 4 (2) ◽  
pp. 58-69 ◽  
Author(s):  
Patricia Fajardo-Cavazos ◽  
Wayne L. Nicholson
Keyword(s):  
Gene Expression ◽  
Bacterial Culture ◽  
Culture Conditions ◽  
Media Culture ◽  
Ground Control ◽  
Biological Research ◽  
Confounding Factors ◽  
Cross Experiment ◽  
Spaceflight Experiments ◽  
Control Samples

AbstractThe NASA GeneLab Data System (GLDS) was recently developed to facilitate cross-experiment comparisons in order to understand the response of microorganisms to the human spaceflight environment. However, prior spaceflight experiments have been conducted using a wide variety of different hardware, media, culture conditions, and procedures. Such confounding factors could potentially mask true differences in gene expression between spaceflight and ground control samples. In an attempt to mitigate such confounding factors, we describe here the development of a standardized set of hardware, media, and protocols for liquid cultivation of microbes in Biological Research in Canisters (BRIC) spaceflight hardware, using the model bacteria Bacillus subtilis strain 168 and Staphylococcus aureus strain UAMS-1 as examples.

scholarly journals Age and Gender as Cyber Attribution Features in Keystroke Dynamic-Based User Classification Processes

Electronics ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 835
Author(s):  
Ioannis Tsimperidis ◽  
Cagatay Yucel ◽  
Vasilios Katos
Keyword(s):  
High Accuracy ◽  
Keystroke Dynamics ◽  
Time Intervals ◽  
Age And Gender ◽  
Common Features ◽  
User Classification ◽  
Gender And Age ◽  
And Gender ◽  
Keystroke Dynamic

Keystroke dynamics are used to authenticate users, to reveal some of their inherent or acquired characteristics and to assess their mental and physical states. The most common features utilized are the time intervals that the keys remain pressed and the time intervals that are required to use two consecutive keys. This paper examines which of these features are the most important and how utilization of these features can lead to better classification results. To achieve this, an existing dataset consisting of 387 logfiles is used, five classifiers are exploited and users are classified by gender and age. The results, while demonstrating the application of these two characteristics jointly on classifiers with high accuracy, answer the question of which keystroke dynamics features are more appropriate for classification with common classifiers.

Methamphetamine use and psychotic symptoms: findings from a New Zealand longitudinal birth cohort

2021 ◽  
pp. 1-8
Author(s):  
Joseph M. Boden ◽  
James A. Foulds ◽  
Giles Newton-Howes ◽  
Rebecca McKetin
Keyword(s):  
New Zealand ◽  
General Population ◽  
Birth Cohort ◽  
Individual Characteristics ◽  
Psychotic Symptoms ◽  
Confounding Factors ◽  
Long Term Effects ◽  
Methamphetamine Use ◽  
Increased Risk ◽  
Psychosis Risk

Abstract Background This study examined the association between methamphetamine use and psychotic symptoms in a New Zealand general population birth cohort (n = 1265 at birth). Methods At age 18, 21, 25, 30, and 35, participants reported on their methamphetamine use and psychotic symptoms in the period since the previous interview. Generalized estimating equations modelled the association between methamphetamine use and psychotic symptoms (percentage reporting any symptom, and number of symptoms per participant). Confounding factors included childhood individual characteristics, family socioeconomic circumstances and family functioning. Long term effects of methamphetamine use on psychotic symptoms were assessed by comparing the incidence of psychotic symptoms at age 30–35 for those with and without a history of methamphetamine use prior to age 30. Results After adjusting for confounding factors and time-varying covariate factors including concurrent cannabis use, methamphetamine use was associated with a modest increase in psychosis risk over five waves of data (adjusted odds ratio (OR) 1.33, 95% confidence interval (CI) 1.03–1.72 for the percentage measure; and IRR 1.24, 95% CI 1.02–1.50 for the symptom count measure). The increased risk of psychotic symptoms was concentrated among participants who had used at least weekly at any point (adjusted OR 2.85, 95% CI 1.21–6.69). Use of methamphetamine less than weekly was not associated with increased psychosis risk. We found no evidence for a persistent vulnerability to psychosis in the absence of continuing methamphetamine use. Conclusion Methamphetamine use is associated with increased risk of psychotic symptoms in the general population. Increased risk is chiefly confined to people who ever used regularly (at least weekly), and recently.

scholarly journals Polyphenol-Rich and Alcoholic Beverages and Metabolic Status in Adults Living in Sicily, Southern Italy

Foods ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 383
Author(s):  
Agnieszka Micek ◽  
Justyna Godos ◽  
Achille Cernigliaro ◽  
Raffaele Ivan Cincione ◽  
Silvio Buscemi ◽  
...  
Keyword(s):  
Risk Factors ◽  
Southern Italy ◽  
Scientific Evidence ◽  
Alcoholic Beverage ◽  
Metabolic Risk Factors ◽  
Metabolic Status ◽  
Alcoholic Beverages ◽  
Metabolic Risk ◽  
Confounding Factors ◽  
Beverage Consumption

Polyphenol-rich beverage consumption is not univocally accepted as a risk modulator for cardio-metabolic risk factors, despite mechanistic and epidemiological evidence suggesting otherwise. The aim of this study was to assess whether an association between polyphenol-rich beverage consumption and metabolic status could be observed in a Mediterranean cohort with relatively low intake of tea, coffee, red and white wine, beer, and fresh citrus juice. Demographic and dietary characteristics of 2044 adults living in southern Italy were analyzed. Multivariate logistic regression analyses were used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) of the association between polyphenol-rich and alcoholic beverage consumption and metabolic status adjusted for potential confounding factors. Specific polyphenol-rich beverages were associated, to a various extent, with metabolic outcomes. Individuals with a higher total polyphenol-rich beverages had higher polyphenols intake and were less likely to have hypertension, type-2 diabetes, and dyslipidemia (OR = 0.57, 95% CI: 0.44–0.73; OR = 0.41, 95% CI: 0.26–0.66; and OR = 0.41, 95% CI: 0.29–0.57, respectively). However, when adjusted for potential confounding factors, only the association with hypertension remained significant (OR = 0.69, 95% CI: 0.50–0.94). Current scientific evidence suggests that such beverages may play a role on cardio-metabolic risk factors, especially when consumed within the context of a dietary pattern characterized by an intake of a plurality of them. However, these associations might be mediated by an overall healthier lifestyle.

scholarly journals Antithrombotic drugs have a minimal effect on intraoperative blood loss during emergency surgery for generalized peritonitis: a nationwide retrospective cohort study in Japan

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Tadashi Matsuoka ◽  
Nao Ichihara ◽  
Hiroharu Shinozaki ◽  
Kenji Kobayashi ◽  
Alan Kawarai Lefor ◽  
...  
Keyword(s):  
Cohort Study ◽  
Propensity Score ◽  
Blood Loss ◽  
Emergency Surgery ◽  
Retrospective Cohort ◽  
Confounding Factors ◽  
Intraoperative Blood Loss ◽  
Antithrombotic Drugs ◽  
Generalized Peritonitis ◽  
Blood Loss Volume

Abstract Background The effect of antithrombotic drugs on intraoperative operative blood loss volume in patients undergoing emergency surgery for generalized peritonitis is not well defined. The purpose of this study was to investigate the effect of antithrombotic drugs on intraoperative blood loss in patients with generalized peritonitis using a nationwide surgical registry in Japan. Method This retrospective cohort study used a nationwide surgical registry data from 2011 to 2017 in Japan. Propensity score matching for the use of antithrombotic drugs was used for the adjustment of age, gender, comorbidities, frailty, preoperative state, types of surgery, surgical approach, laboratory data, and others. The main outcome was intraoperative blood loss: comparison of intraoperative blood loss, ratio of intraoperative blood loss after adjusted for confounding factors, and variable importance of all covariates. Results A total of 70,105 of the eligible 75,666 patients were included in this study, and 2947 patients were taking antithrombotic drugs. Propensity score matching yielded 2864 well-balanced pairs. The blood loss volume was slightly higher in the antithrombotic drug group (100 [10–349] vs 70 [10–299] ml). After adjustment for confounding factors, the use of antithrombotic drugs was related to a 1.30-fold increase in intraoperative blood loss compared to non-use of antithrombotic drugs (95% CI, 1.16–1.45). The variable importance revealed that the effect of the use of antithrombotic drugs was minimal compared with surgical approach or type of surgery. Conclusion This study shows that while taking antithrombotic drugs is associated with a slight increase in intraoperative blood loss in patients undergoing emergency surgery for generalized peritonitis, the effect is likely of minimal clinical significance.

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