The effects of language proficiency and awareness of time limit in animated vs. text-based situational judgment tests.

BACKGROUND: Situational Judgment Tests (SJTs) are commonly used in medical school admissions. However, it has been consistently found that native speakers tend to score higher on SJTs than non-native speakers, which can be particularly problematic in the admission context due to the potential risk of limited fairness. Besides type of SJT, awareness of time limit may play a role in subgroup differences in the context of cognitive load theory. This study examined the influence of SJT type and awareness of time limit against the background of language proficiency in a quasi high-stakes setting. METHODS: Participants (N = 875), applicants and students in healthcare-related study programs, completed an online study that involved two SJTs: one with a text-based stimulus and response format (HAM-SJT) and another with a video-animated stimulus and media-supported response format (Social Shapes Test, SST). They were randomly assigned to a test condition in which they were either informed about a time limit or not. In a multilevel model analysis, we examined the main effects and interactions of the predictors (test type, language proficiency and awareness of time limit) on test performance (overall, response percentage). RESULTS: There were significant main effects on overall test performance for language proficiency in favor of native speakers and for awareness of time limit in favor of being aware of the time limit. Furthermore, an interaction between language proficiency and test type was found, indicating that subgroup differences are smaller for the animated SJT than for the text-based SJT. No interaction effects on overall test performance were found that included awareness of time limit. CONCLUSION: A SJT with video-animated stimuli and a media-supported response format can reduce subgroup differences in overall test performance between native and non-native speakers in a quasi high-stakes setting. Awareness of time limit is equally important for high and low performance, regardless of language proficiency or test type.

Perceived job insecurity and task performance: what aspect of performance is related to which facet of job insecurity.

Employee task performance is considered to be of crucial importance for organizational survival and growth, at the same time, the struggle for organizational survival and growth most especially in the current economic climate gives rise to perceptions of job insecurity among employees thereby making the perception of job insecurity a relevant topic. This study examined the effect of perceived job insecurity on task performance. In addition, the effect of both quantitative and qualitative facets of job insecurity on the different components of task performance, was investigated. By making use of the multi-stage sampling technique, a total of 342 employees with age range of 23 to 46 years were proportionately selected from the cluster that represents each bank. Furthermore, the close ended and structured questionnaire was utilized in a descriptive cross-sectional research design to elicit responses from these employees. Based on the regression analysis conducted, it was revealed that while perceived job insecurity as a uni-dimensional construct exercise a significant and negative effect on task performance, both quantitative and qualitative job insecurity also have a significant and negative effect on this performance with the later, found to exercise a stronger negative impact. Furthermore, results also indicate that while quantitative job insecurity is more negatively related with the job quality component of performance, both job quantity and job time limit are more negatively related with qualitative job insecurity. To conclude, recommendations were made on the need for organizations to focus intervention on antecedents of job insecurity which have been classified as macro level, micro level and personality factors with the view of reducing the incidence of perceived job insecurity. It was also recommended that managers should endeavor to concentrate more resources on those employees who suffer from qualitative job insecurity whenever there is a need to make use of these interventions, while also being in cognizant of the fact that a different level of intervention is required for employees with different level of job quality, job quantity and job time limit.

Differences in attention, hand dexterity, and lower extremity activities in the presence or absence of a time limit.

[Purpose] The purpose of this study was to investigate how a time limit affects day-to-day tasks such as attention, hand dexterity, and sit to standing and sitting activity. The grounds for using a time limit as a method of learning tasks related to daily living are examined based on the results of this investigation. [Subjects and Methods] The subjects consisted of 51 healthy college students (20 males and 31 females). The task performance time for SESSION 1, in which there was no time limit, was measured and the task duration privately recorded. The task performance for SESSION 2 was then measured with a time limit of the same duration as the time recorded for SESSION 1. Attention was measured using the trail-making test, hand dexterity using the Purdue pegboard test, and lower extremity activity using the sit to standing and sitting test. [Results] The levels for the attention, hand dexterity, and lower extremity activities were high in the environment in which a time limit was set. The differences between the genders depending on the presence or absence of a time limit was insignificant. [Conclusion] A time limit environment can be used as a task-training method for attention, hand dexterity, and lower extremity activities.

Uncontrolled Web-based administration of surveys on factual health-related knowledge: a randomized study of untimed versus timed quizzing.

BACKGROUND: Health knowledge and literacy are among the main determinants of health. Assessment of these issues via Web-based surveys is growing continuously. Research has suggested that approximately one-fifth of respondents submit cribbed answers, or cheat, on factual knowledge items, which may lead to measurement error. However, little is known about methods of discouraging cheating in Web-based surveys on health knowledge. OBJECTIVE: This study aimed at exploring the usefulness of imposing a survey time limit to prevent help-seeking and cheating. METHODS: On the basis of sample size estimation, 94 undergraduate students were randomly assigned in a 1:1 ratio to complete a Web-based survey on nutrition knowledge, with or without a time limit of 15 minutes (30 seconds per item); the topic of nutrition was chosen because of its particular relevance to public health. The questionnaire consisted of two parts. The first was the validated consumer-oriented nutrition knowledge scale (CoNKS) consisting of 20 true/false items; the second was an ad hoc questionnaire (AHQ) containing 10 questions that would be very difficult for people without health care qualifications to answer correctly. It therefore aimed at measuring cribbing and not nutrition knowledge. AHQ items were somewhat encyclopedic and amenable to Web searching, while CoNKS items had more complex wording, so that simple copying/pasting of a question in a search string would not produce an immediate correct answer. RESULTS: A total of 72 of the 94 subjects started the survey. Dropout rates were similar in both groups (11%, 4/35 and 14%, 5/37 in the untimed and timed groups, respectively). Most participants completed the survey from portable devices, such as mobile phones and tablets. To complete the survey, participants in the untimed group took a median 2.3 minutes longer than those in the timed group; the effect size was small (Cohen's r=.29). Subjects in the untimed group scored significantly higher on CoNKS (mean difference of 1.2 points, P=.008) and the effect size was medium (Cohen's d=0.67). By contrast, no significant between-group difference in AHQ scores was documented. Unexpectedly high AHQ scores were recorded in 23% (7/31) and 19% (6/32) untimed and timed respondents, respectively, very probably owing to "e-cheating". CONCLUSIONS: Cribbing answers to health knowledge items in researcher-uncontrolled conditions is likely to lead to overestimation of people's knowledge; this should be considered during the design and implementation of Web-based surveys. Setting a time limit alone may not completely prevent cheating, as some cheats may be very fast in Web searching. More complex and contextualized wording of items and checking for the "findability" properties of items before implementing a Web-based health knowledge survey may discourage help-seeking, thus reducing measurement error. Studies with larger sample sizes and diverse populations are needed to confirm our results.

Improving and Extending STERGM Approximations Based on Cross-Sectional Data and Tie Durations.

Temporal exponential-family random graph models (TERGMs) are a flexible class of models for network ties that change over time. Separable TERGMs (STERGMs) are a subclass of TERGMs in which the dynamics of tie formation and dissolution can be separated within each discrete time step and may depend on different factors. The Carnegie et al. (2015) approximation improves estimation efficiency for a subclass of STERGMs, allowing them to be reliably estimated from inexpensive cross-sectional study designs. This approximation adapts to cross-sectional data by attempting to construct a STERGM with two specific properties: a cross-sectional equilibrium distribution defined by an exponential-family random graph model (ERGM) for the network structure, and geometric tie duration distributions defined by constant hazards for tie dissolution. In this paper we focus on approaches for improving the behavior of the Carnegie et al. approximation and increasing its scope of application. We begin with Carnegie et al.'s observation that the exact result is tractable when the ERGM is dyad-independent, and then show that taking the sparse limit of the exact result leads to a different approximation than the one they presented. We show that the new approximation outperforms theirs for sparse, dyad-independent models, and observe that the errors tend to increase with the strength of dependence for dyad-dependent models. We then develop theoretical results in the dyad-dependent case, showing that when the ERGM is allowed to have arbitrary dyad-dependent terms and some dyad-dependent constraints, both the old and new approximations are asymptotically exact as the size of the STERGM time step goes to zero. We note that the continuous-time limit of the discrete-time approximations has the desired cross-sectional equilibrium distribution and exponential tie duration distributions with the desired means. We show that our results extend to hypergraphs, and we propose an extension of the Carnegie et al. framework to dissolution hazards that depend on tie age.

The Impact of ABAWD Time Limit Reinstatement on SNAP Participation and Employment.

OBJECTIVE: Estimate the impact of the Supplemental Nutrition Assistance Program (SNAP) time limit for able-bodied adults without dependents (ABAWD) on SNAP participation, employment, and earnings. DESIGN: A quasi-experimental study using state administrative SNAP and earnings data to compare outcomes for SNAP participants before and after the time limit went into effect. PARTICIPANTS: Supplemental Nutrition Assistance Program participants in the study cohorts in Colorado, Missouri, and Pennsylvania (N = 153,599). MAIN OUTCOME MEASURES: Monthly SNAP participation, quarterly employment, annual earnings. ANALYSIS: Logistic and ordinary least squares multivariate regression models. RESULTS: Time limit reinstatement reduced SNAP participation by 7 to 32 percentage points in the 12th month of time limit reinstatement but did not generate evidence of improved employment or annual earnings (1 year after time limit reinstatement, employment decreased by 2 to 7 percentage points and annual earnings decreased by $247 to $1,230). CONCLUSIONS AND IMPLICATIONS: The ABAWD time limit reduced SNAP participation but did not improve employment and earnings. SNAP may provide helpful support to participants as they seek to enter or re-enter employment, and removing this support may be detrimental to their employment prospects. These findings can inform decisions about requesting waivers or pursuing changes to ABAWD legislation or regulations.

Remembering Sets: Capacity Limit and Time Limit of Ensemble Representations in Working Memory.

In a constantly changing visual environment, the ability to extract and store ensemble representations plays a crucial role in efficiently processing and remembering complex visual information. However, how working memory maintains these ensemble representations remains unclear. Therefore, the present study aimed to investigate the limits and characteristics of ensemble representations in working memory using a change detection paradigm. Participants were presented with multiple sets of circles grouped by spatial proximity and were asked to memorize the mean diameter of the circles in each set. Results showed that working memory could stably maintain mean sizes of approximately two sets for at least four seconds. Moreover, the memory performance of ensembles was not affected by the number of circles within a set, suggesting that individual details were not stored in working memory. These results suggest that the visual system can effectively store ensembles in working memory without preserving detailed individual information.

Time limit and V̇O2 kinetics at maximal aerobic velocity: Continuous vs. intermittent swimming trials.

The time sustained during exercise with oxygen uptake (V̇O2) reaching maximal rates (V̇O2peak) or near peak responses (i.e., above second ventilatory threshold [t@VT2) or 90% V̇O2peak (t@90%V̇O2peak)] is recognized as the training pace required to enhance aerobic power and exercise tolerance in the severe domain (time-limit, tLim). This study compared physiological and performance indexes during continuous and intermittent trials at maximal aerobic velocity (MAV) to analyze each exercise schedule, supporting their roles in conditioning planning. Twenty-two well-trained swimmers completed a discontinuous incremental step-test for V̇O2peak, VT2, and MAV assessments. Two other tests were performed in randomized order, to compare continuous (CT) vs. intermittent trials (IT100) at MAV until exhaustion, to determine peak oxygen uptake (Peak-V̇O2) and V̇O2 kinetics (V̇O2K). Distance and time variables were registered to determine the tLim, t@VT2, and t@90%V̇O2peak tests. Blood lactate concentration ([La-]) was analyzed, and rate of perceived exertion (RPE) was recorded. The tests were conducted using a breath-by-breath apparatus connected to a snorkel for pulmonary gas sampling, with pacing controlled by an underwater visual pacer. V̇O2peak (55.2 ± 5.6 ml·kg·min-1) was only reached in CT (100.7 ± 3.1 %V̇O2peak). In addition, high V̇O2 values were reached at IT100 (96.4 ± 4.2 %V̇O2peak). V̇O2peak was highly correlated with Peak-V̇O2 during CT (r = 0.95, p < 0.01) and IT100 (r = 0.91, p < 0.01). Compared with CT, the IT100 presented significantly higher values for tLim (1,013.6 ± 496.6 vs. 256.2 ± 60.3 s), distance (1,277.3 ± 638.1 vs. 315.9 ± 63.3 m), t@VT2 (448.1 ± 211.1 vs. 144.1 ± 78.8 s), and t@90%V̇O2peak (321.9 ± 208.7 vs. 127.5 ± 77.1 s). V̇O2K time constants (IT100: 25.9 ± 9.4 vs. CT: 26.5 ± 7.5 s) were correlated between tests (r = 0.76, p < 0.01). Between CT and IT100, tLim were not related, and RPE (8.9 ± 0.9 vs. 9.4 ± 0.8) and [La-] (7.8 ± 2.7 vs. 7.8 ± 2.8 mmol·l-1) did not differ between tests. MAV is suitable for planning swimming intensities requiring V̇O2peak rates, whatever the exercise schedule (continuous or intermittent). Therefore, the results suggest IT100 as a preferable training schedule rather than the CT for aerobic capacity training since IT100 presented a significantly higher tLim, t@VT2, and t@90%V̇O2peak (∼757, ∼304, and ∼194 s more, respectively), without differing regards to [La-] and RPE. The V̇O2K seemed not to influence tLim and times spent near V̇O2peak in both workout modes.

Ephemerality in Social Media: Unpacking the Personal and Social Characteristics of Time Limit Users on WeChat Moments.

Social media platforms increasingly give users the option of ephemerality through settings that delete or hide posted content after a set period of time. Many individuals apply these settings to manage their posting history and, in turn, reduce concerns about self-presentation. Despite the growing popularity of this feature, few studies have empirically explored it. This study examines the Time Limit setting on WeChat Moments as an example and investigates how users using the Time Limit setting differ from nonusers in terms of personal characteristics (demographics, personality traits, psychological factors, and previous behavioral patterns) and social characteristics (audience size and audience diversity). Compared with nonusers, users using Time Limit setting scored significantly higher on posting frequency and privacy setting use and scored significantly lower on audience size. We also examine how personal and social characteristics vary between user groups with different degrees of ephemerality (i.e., low, medium, or high). Our findings show that users using the Time Limit setting who scored higher on measures of life changes, self-monitoring, posting frequency, and audience size and lower on perceived stress were more likely to opt for the low (i.e., 6months) rather than the medium (i.e., 1month) or high (i.e., 3days) degree of ephemerality. Our work contributes to the understanding of ephemerality settings on social media platforms and provides insights that help practitioners design more effective platforms.

The Impact of Embryo Storage Time on Pregnancy and Perinatal Outcomes and the Time Limit of Vitrification: A Retrospective Cohort Study.

Background: The technique of embryo cryopreservation has been increasingly applied in clinical settings. However, there has been a concern about the safety and efficacy of long-term freezing of embryos. Therefore, the aim of this study was to evaluate whether storage time of vitrification had any effects on pregnancy as well as perinatal outcomes, further, to explore the appropriate time limit of vitrification. Methods: The study included women who underwent at least one frozen-thawed cycle with single embryo transfer between January 1st, 2016 and September 30th, 2019. Patients were assigned into 3 groups according to the storage time (<3 months, 3-12 months and >12 months) to evaluate the impact of embryo storage time on pregnancy and perinatal outcomes. To further investigate the time limit of vitrification, propensity score matching was used to compare the primary outcomes of patients with storage time of 1-3 years, 3-5 years, and >5 years to those stored for ≤1 year. Results: A total of 9806 frozen-thawed embryo transfer cycles were included in our study. After adjustment for confounding variables, no significant differences were found in pregnancy outcomes among groups. However, postponement of transfer increased the risks of large for gestational age and placenta previa. In addition, after propensity score matching, 171 cycles with storage time >5 years were matched with those ≤1 year, both the clinical pregnancy rate and live birth rate decreased significantly when the storage time exceeded 5 years. Conclusions: The duration of vitrification did not significantly affect the pregnancy outcomes within 5 years period. However, the clinical pregnancy rate and live birth rate both decreased significantly when the duration of vitrification exceeded 5 years. It is worth noting that the conclusion was drawn from a small sample study after propensity score matching and should be treated with caution. In addition, the cycles were from different time periods, which could have an impact on the results.

The effect of an Olympic distance triathlon on the respiratory muscle strength and endurance in triathletes.

High-intensity exercise, marathons, and long distances triathlons have been shown to induce the fatigue of respiratory muscles (RMs). Never-theless, fatigue and the recovery period have not been studied in re-sponse of an Olympic distance triathlon (1.5-km swim, 40-km bike, 10-km run: short-distance triathlon). The aim of this study was to evaluate the RM fatigue induced by an Olympic distance triathlon. Nine male triath-letes (24±1.1 years) underwent spirometric testing and the assessment of RM performance. Respiratory function tests were conducted in sit-ting position. Spirometric parameters, maximal inspiratory and expirato-ry pressures, and RM endurance assessed by measuring the time limit were evaluated before (pre-T), after (post-T), and the day following the triathlon (post-T-24 hr). Residual volume increased: pre-T vs. post-T (P<0.002), maximal inspiratory pressure significantly decreased from 127.4±17.2 (pre-T) to 121.6±18.5 cmH2O (post-T) (P<0.001) and returned to the pre-T value 24 hr after the race (125.0±18.6). RM endurance sig-nificantly decreased from 4:51±0:8 (pre-T) to 3:13±0:7 min (post-T, P< 0.001) and then remained decreased for 24 hr after the race from 4:51± 0:8 (pre-T) to 3:39±0:4 min 24 hr after (P<0.002). Both, strength and en-durance of inspiratory muscles decrease after Olympic distance triath-lon. Furthermore, the impaired of inspiratory muscle endurance 24 hr after the race suggested a slow recovery and persistence of inspiratory muscle fatigue.

How Do Time Limits Affect Our Psychotherapies? A Literature Review.

The application of time limits (i.e. restricting the amount of sessions before the beginning of psychotherapy) has become ingrained in psychotherapy research and in the context of managed care, mostly due to pragmatic and economic reasons. However, little is know on how this technique interferes with the psychotherapeutic process. Although several theorists have considered the possible advantages and drawbacks of the technique, research explaining these mechanisms is scattered. By conducting this review, we strived to answer two questions: (1) Does a time limit alter the psychotherapeutic process? And (2) In what way? In doing so, this study aspires to grant more insight into the mechanisms of time limited psychotherapy and aimes to contribute to a first understanding of the dynamics of a time restricted therapy process. We searched for articles in the databases of Web of Science and Pubmed. Our review identified 28 studies that provide empirical grounds to explain processes involved when applying a time limit to psychotherapy. Qualitative research suggests that a time limit exerts pressure on the therapy process and creates an expectancy effect, which can have both positive and negative consequences. Additionally, time limits can be associated to therapists taking on a more directive role in therapy. Results show that a time limit is anything but a neutral intervention; it is a technique that complexly interacts with therapy processes on multiple grounds. Further research is vital to determine which environment is appropriate for its application.

Using Response Times to Model Not-Reached Items due to Time Limits.

Missing values at the end of a test typically are the result of test takers running out of time and can as such be understood by studying test takers' working speed. As testing moves to computer-based assessment, response times become available allowing to simulatenously model speed and ability. Integrating research on response time modeling with research on modeling missing responses, we propose using response times to model missing values due to time limits. We identify similarities between approaches used to account for not-reached items (Rose et al. in ETS Res Rep Ser 2010:i-53, 2010) and the speed-accuracy (SA) model for joint modeling of effective speed and effective ability as proposed by van der Linden (Psychometrika 72(3):287-308, 2007). In a simulation, we show (a) that the SA model can recover parameters in the presence of missing values due to time limits and (b) that the response time model, using item-level timing information rather than a count of not-reached items, results in person parameter estimates that differ from missing data IRT models applied to not-reached items. We propose using the SA model to model the missing data process and to use both, ability and speed, to describe the performance of test takers. We illustrate the application of the model in an empirical analysis.

A Speed-Accuracy Tradeoff Hierarchical Model Based on Cognitive Experiment.

Most tests are administered within an allocated time. Due to the time limit, examinees might have different trade-offs on different items. In educational testing, the traditional hierarchical model cannot adequately account for the tradeoffs between response time and accuracy. Because of this, some joint models were developed as an extension of the traditional hierarchical model based on covariance. However, they cannot directly reflect the dynamic relationship between response time and accuracy. In contrast, response moderation models took the residual response time as the independent variable of the response model. Nevertheless, the models enlarge the time effect. Alternatively, the speed-accuracy tradeoff (SAT) model is superior to other experimental models in the SAT experiment. Therefore, this paper incorporates the SAT model with the traditional hierarchical model to establish a SAT hierarchical model. The results demonstrated that the Bayesian Markov chain Monte Carlo (MCMC) algorithm performed well in the SAT hierarchical model of parameters by using simulation. Finally, the deviance information criterion (DIC) more preferred the SAT hierarchical model than other models in empirical data. This means that it is indispensable to add the effect of response time on accuracy, but likewise should limit the effect on the empirical data.

Does the Effect of a Time Limit for Testing Impair Structural Investigations by Means of Confirmatory Factor Models?

The article reports three simulation studies conducted to find out whether the effect of a time limit for testing impairs model fit in investigations of structural validity, whether the representation of the assumed source of the effect prevents impairment of model fit and whether it is possible to identify and discriminate this method effect from another method effect. Omissions due to the time limit for testing were not considered as missing data but as information on the participants' processing speed. In simulated data the presence of a time-limit effect impaired comparative fit index and nonnormed fit index whereas normed chi-square, root mean square error of approximation, and standardized root mean square residual indicated good model fit. The explicit consideration of the effect due to the time limit by an additional component of the model improved model fit. Effect-specific assumptions included in the model of measurement enabled the discrimination of the effect due to the time limit from another possible method effect.

Effects of transcranial direct current stimulation on time limit and ratings of perceived exertion in physically active women.

The limiting factors of maximum performance in humans have been extensively investigated. The aim of this study was to verify the acute effects of transcranial direct current stimulation on time limit (i.e., the time by which an individual is able to sustain a certain intensity of effort) at 100% of peak power (tlim@100%PP) and ratings of perceived exertion (RPE). Eleven moderately active women underwent an anthropometric evaluation and a maximal incremental test in the cycle ergometer, in order to obtain peak power (PP). At the two subsequent visits, which were separated by 48-72h, participants were randomly assigned to two experimental conditions: anodal stimulation (a-tDCS) and sham. In the a-tDCS condition, the stimulus was applied in the left dorsolateral prefrontal cortex (DLPFC), with intensity of 2mA for 20min. In the sham condition, the equipment was switched off after 30s of stimulation. Immediately after the conditions, participants performed the tlim@100%PP. Immediately after the tlim@100%PP test, the RPE scale was applied. The results demonstrated that the tlim@100%PP was higher in a-tDCS condition compared to sham condition (p=0.005). No difference was found between the conditions (a-tDCS vs sham) for the RPE (p=0.52). The anodal stimulus increased the tolerance to the exercise performed in the cycloergometer with maximum load, having some ergogenic effect in exercises of cyclic characteristics.

The relationship between the changes of electrocardiogram QRS duration features and the occurrence of adverse cardiac events in patients with heart failure / 中国基层医药

Objective:To investigate the relationship between the changes of electrocardiogram QRS duration features and the occurrence of adverse cardiac events in patients with heart failure.Methods:The clinical data of 298 patients with heart failure who received treatment in Lishui City People's Hospital from June 2021 to June 2022 were retrospectively analyzed. According to the type of heart failure, they were divided into the diastolic heart failure group ( n = 158) and the systolic heart failure group ( n= 140). According to whether having cardiac events, they were divided into a cardiac event group ( n = 97) and a non-cardiac event group ( n = 201) group. An additional 120 patients who concurrently received health examinations were included in the control group. QRS wave duration and cardiac function indicators were analyzed. QRS wave duration and cardiac function indicators were compared between heart failure and control groups. Changes in QRS wave duration and cardiac function indicators were compared between diastolic heart failure and systolic heart failure groups. Changes in QRS wave duration and cardiac function indicators were compared between cardiac event and non-cardiac event groups. The value of the receiver operating characteristic curve in predicting adverse cardiac events was analyzed. Pearson correlation analysis was performed to analyze the correlation between QRS wave duration and cardiac function. Results:QRS wave duration in the heart failure group was (125.42 ± 14.35) ms, which was significantly longer than (78.82 ± 6.49) ms in the control group ( t = 34.17, P < 0.001). Left ventricular end-systolic volume (LVESV) and left ventricular end-diastolic volume (LVEDV) in the heart failure group were (156.24 ± 21.42) mL and (78.28 ± 9.43) mL, respectively, which were significantly higher than (107.48 ± 19.23) mL and (45.62 ± 5.42) mL, respectively in the control group ( t = 21.66, 35.63, both P < 0.01). Left ventricular ejection fraction (LVEF) in the heart failure group was (46.98 ± 4.25)%, which was significantly lower than (67.94 ± 5.46)% in the control group ( t = 41.88, P < 0.001). QRS wave duration in the systolic heart failure group was (140.21 ± 18.57) ms, which was significantly longer than (112.31 ± 13.42) ms in the diastolic heart failure group ( t = 16.29, P < 0.001). LVESV and LVEDV in the systolic heart failure group were (183.36 ± 27.67) mL and (95.39 ± 12.13) mL, respectively, which were significantly higher than (132.21 ± 18.98) mL and (63.12 ± 7.84) mL in the diastolic heart failure group ( t = 20.30, 29.61, both P < 0.001). LVEF in the systolic heart failure group was (38.19 ± 4.61)%, which was significantly lower than (54.77 ± 4.92)% in the diastolic heart failure group ( t = 34.18, P < 0.001). QRS wave duration in the cardiac event group was (169.37 ± 17.43) ms, which was significantly longer than (104.21 ± 12.49) ms in the non-cardiac event group ( t = 36.91, P < 0.001). LVESV and LVEDV in the cardiac event group were (199.30 ± 23.41) mL and (105.22 ± 15.64) mL, respectively which were significantly higher than (135.46 ± 15.46) mL and (65.28 ± 6.92) mL in the non-cardiac event group ( t = 28.04, 30.57, both P < 0.001). LVEF in the cardiac event group was (32.97 ± 5.16)%, which was significantly lower than (53.74 ± 4.52)% in the non-cardiac event group ( t = 35.46, P < 0.001). The receiver operating characteristic curve analysis showed that the sensitivity and specificity of QRS wave duration in predicting adverse cardiac events were 88.7% and 86.6%, respectively. Pearson analysis showed that QRS wave duration, LVESV, and LVEDV were positively correlated with the occurrence of adverse cardiac events ( r = 0.684, 0.546, 0.518, all P < 0.05), while LVEF was negatively correlated with the occurrence of adverse cardiac events ( r = -0.627, P < 0.05). Conclusion:QRS wave duration in patients with heart failure is significantly prolonged, and it is obviously related to the occurrence of adverse cardiac events.

Physiological Responses During the Time Limit at 100% of the Peak Velocity in the Carminatti's Test in Futsal Players.

The aim of this study was to investigate the physiological responses during the time limit at the intensity of the peak velocity of the Carminatti's test (T-CAR). Ten professional futsal players (age, 27.4 ± 5.8 years, body mass, 78.8 ± 8.5 kg, body height, 175.8 ± 6.8 cm, body fat mass, 14.1 ± 2.6%) took part in the study. The players performed three tests, with an interval of at least 48 hours, as follows: the T-CAR to determine the peak velocity and the maximal heart rate; an incremental treadmill protocol to determine the maximal physiological responses; and a time limit running test at the peak velocity reached in the T-CAR. During the last two tests, a portable gas analyzer was used for direct measurement of cardiorespiratory variables. It was shown that the peak velocity was not significantly different from the maximal aerobic speed achieved in the laboratory (p = 0.213). All athletes reached their maximum oxygen uptake during the time limit test. The maximum oxygen uptake achieved during the time limit test was not different from that observed in the laboratory condition (51.1 ± 4.7 vs. 49.6 ± 4.7 ml·kg-1·min-1, respectively, p = 0.100). In addition, Bland and Altman plots evidenced acceptable agreement between them. On average, athletes took ~140 s to achieve maximum oxygen uptake and maintained it for ~180 s. Therefore, the peak velocity intensity can be used as an indicator of maximal aerobic power of futsal athletes and the time limit can be used as a reference for training prescription.

Symmetry of the gradient profile as second experimental dimension in the short-time expansion of the apparent diffusion coefficient as measured with NMR diffusometry.

The time-dependent apparent diffusion coefficient as measured by pulsed gradient NMR can be used to estimate parameters of porous structures including the surface-to-volume ratio and the mean curvature of pores. In this work, the short-time diffusion limit and in particular the influence of the temporal profile of diffusion gradients on the expansion as proposed by Mitra et al. (1993) is investigated. It is shown that flow-compensated waveforms, i.e. those whose first moment is zero, are blind to the term linear in observation time, which is the term that is proportional to mean curvature and surface permeability. A gradient waveform that smoothly interpolates between flow-compensated and bipolar waveform is proposed and the degree of flow-compensation is used as a second experimental dimension. This two-dimensional ansatz is shown to yield an improved precision when characterizing the confining domain. This technique is demonstrated with simulations and in experiments performed with cylindrical capillaries of 100 µm radius.