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PubMed2006

Influence of the contact time on coupling time and a simple method to measure coupling time.

The enhancement of performance in stretch shortening cycle (SSC) exercises has been attributed to the recoil of elastic energy stored during the stretching phase and depends on the duration of the coupling time (T(coupling)) i.e., the duration of the isometric phase occurring between the stretch and the shortening of the muscle. However, instead of T(coupling), the contact time (T(contact))--i.e., the sum of T(coupling) plus the duration of the stretching and shortening phases that precede and follow T(coupling)--is more easily and often measured. The aim of this study was to investigate the T(coupling) changes within a large range of T(contact), in order to propose a possible relationship between T(coupling) and T(contact), thus allowing the accurate measurement of T(coupling )only from a tachometer and force data obtained classically in vertical jumps, jumps on sledge apparatus and running on force treadmills. Eleven subjects performed SSC exercises on a sledge apparatus with a large range of T(contact) (400, 700, 1,000, 1,500, 2,000 and 2,500 ms). The T(coupling) and T(contact) values were measured individually, from force platform recordings and the velocity of the carriage seat obtained by a tachometer. For the longest T(contact) (i.e., from 850 to 2,500 ms), we observed a significant linear relationship between T(contact) and T(coupling). This transition between T(contact) shorter or longer than about 850 ms seems to be important and to correspond to T(coupling) close to 300 ms. This limit observed in the present study could be explained physiologically due to a possible modification of the cross-bridges formation.

Adult↗
PubMed1980

Filling time versus affective response to the activity that fills the time: independent effects on time judgment?

Previous time perception research has confounded manipulations intended to evoke different affective reactions to the task with different levels of nontemporal processing demands. An attempt was made to separate these dimensions by a social comparison procedure aimed at making the same concurrent task (card sorting) appear differentially interesting to two groups of college students. Response uncertainty varied within the task to that processing demands could be compared while reported interest in the task varied between groups. Magnitude of time estimates related inversely to response uncertainty, but reported interest in the task made no independent contribution to the variance of estimates.

Affect↗
PubMed1999

Inverse relation of body-surface activation-recovery interval and recovery time to activation time in normal subjects: stronger correlation and more heterogeneous distribution in activation-recovery interval than in recovery time.

The activation-recovery interval (ARI), measured directly from the myocardium, has shown a good correlation with the action potential duration (APD) in experiments. APD has been reported to be inversely related to the activation time (AT). However, no studies have examined the correlation between the body-surface ARI and AT in normal subjects. Fifty normal subjects (25 men and 25 women) were studied to elucidate the relationship between the body-surface ARI and AT. The body-surface AT was defined as the duration between the QRS onset and the minimum dV/dt of the QRS wave, and ARI as the interval between the minimum dV/dt of the QRS wave and the maximum dV/dt of the T wave in each lead of an 87 unipolar lead system. We also measured the recovery time (RT) defined as the duration between the QRS onset and the maximum dV/dt of the T wave. ARI was inversely correlated with AT (r = -0.73). RT was also inversely correlated with AT (r = -0.61), however, RT had a less heterogeneous distribution than ARI (148 ms vs 159 ms). There were no differences between male and female subjects in the relation between ARI and RT or in the body-surface distribution of ARI and RT. These findings suggest that the body-surface ARI may reflect recovery properties over the cardiac surface and that APD may distribute inhomogeneously over the human cardiac surface with a longer RT over an area with a shorter AT. ARI calculated from body-surface ECG may be a useful noninvasive and repeatedly measurable estimate of APD.

Adolescent↗
PubMed2006

Optimal timing of injection of once-daily insulin glargine in people with Type 1 diabetes using insulin lispro at meal-times.

AIMS: To compare blood glucose control when insulin glargine is given at lunch-time, dinner-time, and bed-time in people with Type 1 diabetes using insulin lispro at meal-times. METHODS: In this 16-week, three-way, cross-over study, 23 people with Type 1 diabetes were randomized to insulin glargine injection at lunch-time (L) [mean 12.37 +/- 00.34 (+/- sd) h], dinner-time (D) (18.12 +/- 00.40 h), or bed-time (B) (22.29 +/- 00.40 h), each plus meal-time insulin lispro. Each 4-week treatment period concluded with a 24-h inpatient metabolic profile. RESULTS: Insulin doses, HbA(1c), and fructosamine concentration did not differ between treatment periods. Pre-breakfast self-monitored blood glucose (SMBG) concentration was higher with injection of glargine at lunch-time than at other times [L: 9.2 +/- 0.3 (+/- se) vs. D: 8.2 +/- 0.3 or B: 8.0 +/- 0.3 mmol/l, P = 0.016], as probably was pre-lunch SMBG (L: 8.6 +/- 0.7 vs. D: 6.4 +/- 0.7 or B: 6.4 +/- 0.8 mmol/l, P = 0.051). Pre-dinner SMBG level was higher with dinner-time glargine than other injection times (D: 9.4 +/- 0.9 vs. L: 4.9 +/- 0.9 or B: 7.4 +/- 1.1 mmol/l, P = 0.007). For 22.00 to 02.00 h, mean inpatient plasma glucose concentration was higher with injection of glargine at bed-time than other times (B: 9.1 +/- 0.6 vs. L: 7.8 +/- 0.6 or D: 6.7 +/- 0.6 mmol/l, P = 0.023). Plasma free insulin concentration was lower at the end of the afternoon with dinner-time glargine than other injection times (D: 11.5 +/- 1.4 vs. L: 20.2 +/- 1.3 or B: 16.5 +/- 1.3 mU/l, P < 0.001). Frequency of hypoglycaemia was not different, but timing of hypoglycaemia differed between treatment periods. CONCLUSIONS: Blood glucose levels rise around the time of injection of insulin glargine whether given at lunch-time, dinner-time or bed-time. Bed-time injection leads to hyperglycaemia in the early part of the night which is improved by giving insulin glargine at lunch-time or dinner-time.

Adolescent↗
PubMed2006

Time well spent? Relating television use to children's free-time activities.

OBJECTIVES: This study assessed the claim that children's television use interferes with time spent in more developmentally appropriate activities. METHODS: Data came from the first wave of the Child Development Supplement, a nationally representative sample of children aged 0 to 12 in 1997 (N = 1712). Twenty-four-hour time-use diaries from 1 randomly chosen weekday and 1 randomly chosen weekend day were used to assess children's time spent watching television, time spent with parents, time spent with siblings, time spent reading (or being read to), time spent doing homework, time spent in creative play, and time spent in active play. Ordinary least squares multiple regression was used to assess the relationship between children's television use and time spent pursuing other activities. RESULTS: Results indicated that time spent watching television both with and without parents or siblings was negatively related to time spent with parents or siblings, respectively, in other activities. Television viewing also was negatively related to time spent doing homework for 7- to 12-year-olds and negatively related to creative play, especially among very young children (younger than 5 years). There was no relationship between time spent watching television and time spent reading (or being read to) or to time spent in active play. CONCLUSIONS: The results of this study are among the first to provide empirical support for the assumptions made by the American Academy of Pediatrics in their screen time recommendations. Time spent viewing television both with and without parents and siblings present was strongly negatively related to time spent interacting with parents or siblings. Television viewing was associated with decreased homework time and decreased time in creative play. Conversely, there was no support for the widespread belief that television interferes with time spent reading or in active play.

Child↗
PubMed2002

Use of a time-flow study to improve patient waiting times at an inner-city academic pediatric practice.

OBJECTIVES: To use findings from a time-flow study at an academic pediatric practice to restructure practice patterns and to repeat the time-flow study to evaluate consequent changes in patient waiting times, total visit times, and room and nursing time usage rates. DESIGN: A before-and-after time-flow evaluation of patient waiting times, total visit times, and room and nursing time usage rates. SETTING: An inner-city academic pediatric practice located at a community health center affiliated with a major urban academic teaching hospital. PATIENTS: All patients visiting the pediatric practice during the weeks of April 26 through 30, 1999, and March 24 through 28, 2000. INTERVENTIONS: Initial time-flow findings generated in telephone messaging, provider scheduling, nursing location, and provider and preceptor documentation. MAIN OUTCOME MEASURES: Patient waiting times, total visit times, room usage rates, and nursing time usage rates. RESULTS: After the implementing of practice changes, mean total visit time declined from 91.9 to 78.3 minutes. Mean waiting time to be called by the nurse decreased 3.2 minutes, mean time spent with the provider decreased 4.6 minutes, and mean time to wait for a preceptor decreased by 8.8 minutes. Multivariate analysis controlling for visit type, provider type, and the type of postvisit interventions found that mean time of visit decreased by 13.6 minutes. Room and nursing time usage rates, resident satisfaction, and quality-of-care indicators remained largely unchanged. CONCLUSIONS: Time-flow studies can be useful instruments for academic ambulatory practices to identify and ameliorate practice inefficiencies without sacrificing quality of teaching or patient care.

Academic Medical Centers↗
PubMed2001

Productivity, quality, and patient satisfaction: comparison of part-time and full-time primary care physicians.

CONTEXT: Although few data are available, many believe that part-time primary care physicians (PCPs) are less productive and provide lower quality care than full-time PCPs. Some insurers exclude part-time PCPs from their provider networks. OBJECTIVE: To compare productivity, quality of preventive care, patient satisfaction, and risk-adjusted resource utilization of part-time and full-time PCPs. DESIGN: Retrospective cohort study. SETTING: Boston. PARTICIPANTS: PCPs affiliated with 2 academic outpatient primary care networks. MEASUREMENTS: PCP productivity, patient satisfaction, resource utilization, and compliance with screening guidelines. RESULTS: Part-time PCP productivity was greater than that of full-time PCPs (2.1 work relative value units (RVUs)/bookable clinical hour versus 1.3 work RVUs/bookable clinical hour, P< .01). A similar proportion of part-time PCPs (80%) and full-time PCPs (75%) met targets for mammography, Pap smears, and cholesterol screening (P = .67). After adjusting for clinical case mix, practice location, gender, board certification status, and years in practice, resource utilization of part-time PCPs (138 dollars [95% confidence interval (CI), 108 dollars to 167 dollars]) was similar to that of full-time PCPs (139 dollars [95% CI, 108 dollars to 170 dollars], P = .92). Patient satisfaction was similar for part-time and full-time PCPs. CONCLUSIONS: In these academic primary care practices, rates of patient satisfaction, compliance with screening guidelines, and resource utilization were similar for part-time PCPs compared to full-time PCPs. Productivity per clinical hour was markedly higher for part-time PCPs. Despite study limitations, these data suggest that academic part-time PCPs are at least as efficient as full-time PCPs and that the quality of their work is similar.

Academic Medical Centers↗
PubMedDate not supplied

Operating room start times and turnover times in a university hospital.

STUDY OBJECTIVE: To measure the start time for the first case of the day and the turnover times for subsequent cases in the operating rooms (ORs) at an academic hospital. DESIGN: Prospective study. SETTING: ORs at a university medical center. PATIENTS: All patients undergoing an operative procedure that started between 7 A.M. and 5 P.M. weekdays for the period January 1, 1989, through June 30, 1989. INTERVENTIONS: For each patient, the following times were recorded: OR ready, patient enters OR, anesthesia induction complete, surgery start, surgery end, patient leaves OR. MEASUREMENTS AND MAIN RESULTS: Patients were brought into the OR just before the scheduled start time. Surgical incision was made 21 to 49 minutes after the patient was brought into the OR. Room turnover time (time from patient in to patient out) was almost uniformly 36 minutes. Patient turnover time (time from end of surgery in one patient to end of induction of next patient) was generally 1 hour. Turnover times were shorter for those ORs in which primarily monitored anesthesia care was provided and longer in ORs in which patients routinely required invasive monitoring. CONCLUSIONS: The scheduled start time for the first case of the day was generally the time the patient was brought into the OR. Because of the variable amount of time required for anesthesia induction and surgical preparation and draping, incision occurred 21 to 49 minutes later. The time between cases when no surgery was occurring was significantly longer than room turnover time because of the need to wake up one patient and induce the following patient. Because of a lack of standardized definitions, there is probably a strong perceptual difference among anesthesiologists, OR nurses, and surgeons when viewing start and turnover times. At our own teaching institution, shortening turnover times would increase the amount of elective OR time available, but the impact would not be significant because the number of procedures done per OR each day is low.

Anesthesia↗
PubMed2004

Times for healing: towards a typology of time-frames in Swiss alcohol and drug clinics.

AIM: To translate theoretical dimensions of 'social time' and 'clock time' in addiction treatment settings into empirical measures and to develop a typology of institutional time perspectives. METHOD: From November 2001 to February 2002, a mail survey was conducted with directors of 57 alcohol and drug clinics in the German-speaking part of Switzerland. Items measured the past and future orientation of the treatment programmes, elements of social time and clock time as part of organizational life and 'time bargaining' between therapists and clients. FINDINGS: Four clusters of temporal orientations emerged: 'clock time keepers' (who emphasize time control and future pessimism); 'nostalgic time riders' (focus on the 'good old days' but individualized planning); 'optimist speeders' (fast pacing, future control); and 'relaxed future optimists' (also future oriented but not sharing the idea of linear time). The time-frame also influences the negotiation of time in treatment between staff and patients: 'relaxed future optimists' most frequently report diverging views, while 'optimist speeders' seem to harmonize the views of patients and treatment staff more easily. Finally, the introduction of the harm reduction policy seems to covary with the ways in which time is viewed and used in treatment organizations. CONCLUSIONS: Treatment programmes differ in their view and use of time. Organizational times with varying dynamics, future-past orientations and time control interact with the organizational structure and socio-environmental factors. The capacity of programmes to adapt to changes in treatment policy and in the treatment system depends to some extent on organizational time orientation.

Attitude of Health Personnel↗
PubMed2006

Door-to-drug and door-to-balloon times: where can we improve? Time to reperfusion therapy in patients with ST-segment elevation myocardial infarction (STEMI).

BACKGROUND: To better understand hospital performance in door-to-drug and door-to-balloon times for patients with STEMI, we examined hospital-level variation in key subintervals of door-to-drug time (door-to-electrocardiogram [ECG] and ECG-to-drug) and of door-to-balloon time (door-to-ECG, ECG-to-lab, lab-to-balloon). We sought to identify achievable subinterval times based on the experience of top performing hospitals. METHODS: We conducted a cross-sectional analysis, using data from the National Registry of Myocardial Infarction, of admissions between January 1, 2001, and December 31, 2002 (20435 patients receiving fibrinolytic therapy in 693 hospitals, and 13387 patients receiving percutaneous coronary intervention in 340 hospitals). Using hierarchical regression modeling, we estimated hospital-level geometric means of each subinterval, adjusted for patient clinical characteristics. We ranked hospitals based on the proportion of patients treated within 30 minutes for door-to-drug time and 90 minutes for door-to-balloon times and compared adjusted subinterval times across these groups. RESULTS: The higher performing hospitals (top 20%) in door-to-drug time and door-to-balloon times had significantly shorter times in nearly all subintervals compared with other hospitals, adjusted for patient clinical characteristics. Adjusted mean subinterval times in higher performing hospitals in door-to-drug time were 6.8 minutes (SD = 1.7) for door-to-ECG and 18.7 minutes (SD = 3.5) for ECG-to-drug. Adjusted mean subinterval times in higher performing hospitals in door-to-balloon time were 7.9 minutes (SD = 1.7) for door-to-ECG, 47.8 minutes (SD = 7.1) for ECG-to-lab, and 29.0 minutes (5.4) for lab-to-balloon, adjusted for patient clinical characteristics. CONCLUSIONS: Substantial national attention is being directed at improving time to treatment of patients with STEMI. These data suggest achievable subinterval times for hospitals seeking to improve performance in this important quality indicator.

Aged↗
PubMed1996

Determination of individual ultrafiltration time (APEX) and purification phosphate time by peritoneal equilibration test: application to individual peritoneal dialysis modality prescription in children.

Efficiency of peritoneal dialysis (PD) is dependent on adequate ultrafiltration (UF) and purification (solute clearance). These two goals apparently seem to conflict in terms of duration of dwells: short dwell time enhances UF capacity and, conversely, long dwell time enhances solute clearance. Peritoneal equilibration test (PET) allows an approach to the ultrafiltration time: the point at which the over time dialysate urea saturation and glucose desaturation curves cross, call APEX time. PET also allows an approach to the purification time: the point at which dialysate-to-plasma (D/P) concentration ratios over time are high. Because of the value of phosphate as a uremic factor of morbidity, we have chosen the time at which D/P phosphate is equal to 0.6 as a purification phosphate dwell time (PPT). A total of 17 patients were studied, over a five-year period, allowing 142 determinations. APEX times (range 18-71 min) and PPT (range 105-238 min) were spread over a wide distribution. PPT and APEX times were significantly shorter in children younger than three years of age than in children older than ten years of age. PPT were nearly four times longer than APEX times. Knowledge of these conflicting ultrafiltration and purification times should help, in our view, in the individual choice of the PD modality: if UF is the major goal, short dwell times should be used (automated PD); if purification is the major goal, long dwell times should be used, as in continuous ambulatory peritoneal dialysis; if both are the target goal, tidal PD should be discussed.

Adolescent↗
PubMed2006

Time is a rubberband: neuronal activity in monkey motor cortex in relation to time estimation.

Anticipation of predictable events is crucial for organizing motor performance. Using instructed delay tasks, it has been shown that even when delay duration is kept constant, reaction time fluctuates from trial to trial. As time estimation is at the core of anticipatory behavior, it is reasonable to speculate whether neuronal delay activity correlates with the subjective estimate of time. As a consequence of the scalar property of time estimation processes, the variability in time estimation increases continuously as time passes during the delay. This scalar property may then be reflected in the increasing variability in neuronal delay activity. We thus studied the influence of temporal prior information on neuronal delay activity in monkey motor cortex in two conceptually different tasks in which two equally probable delay durations were randomly presented. We hypothesized that if one considers the animal's subjective time as the time which elapses between the first (instruction) signal and movement onset, then, by suppressing this temporal variability, across-trial variability in neuronal discharge should decrease. We thus defined a new time scale in each trial such that, after rescaling, the time between the instruction signal and movement onset was identical in all trials. Each spike was then displaced in time accordingly. As expected, the variability in the timing of neuronal peak discharges no longer increased during the trial. This suggests a direct link between the temporal profile of spiking activity and time estimation. The timing of motor cortical activity reflected the 'elasticity' of the animal's subjective time.

Action Potentials↗