Incidence of West Nile virus infection in the Dallas-Fort Worth metropolitan area during the 2012 epidemic.

The 2012 West Nile virus (WNV) epidemic was the largest since 2003 and the North Texas region was the most heavily impacted. We conducted a serosurvey of blood donors from four counties in the Dallas-Fort Worth area to characterize the epidemic. Blood donor specimens collected in November 2012 were tested for WNV-specific antibodies. Donors positive for WNV-specific IgG, IgM, and neutralizing antibodies were considered to have been infected in 2012. This number was adjusted using a multi-step process that accounted for timing of IgM seroreversion determined from previous longitudinal studies of WNV-infected donors. Of 4971 donations screened, 139 (2·8%) were confirmed WNV IgG positive, and 69 (1·4%) had IgM indicating infection in 2012. After adjusting for timing of sampling and potential seroreversion, we estimated that 1·8% [95% confidence interval (CI) 1·5-2·2] of the adult population in the Dallas-Fort Worth area were infected during 2012. The resulting overall estimate for the ratio of infections to reported WNV neuroinvasive disease (WNND) cases was 238:1 (95% CI 192-290), with significantly increased risk of WNND in older age groups. These findings were very similar to previous estimates of infections per WNND case, indicating no change in virulence as WNV evolved into an endemic infection in the United States.

The role of primary tumour resection in patients with stage IV colorectal cancer.

OBJECTIVE: The management of stage IV colorectal cancer is controversial. Resection of the primary tumour to prevent obstruction, bleeding or perforation is the traditional approach, although survival benefit is undetermined. Management consisting of diverting ostomy, enteric bypass, laser recanalization or endoscopic stenting is an alternative to radical resection. The purpose of this study was to determine the role of resection of the primary tumour in patients with stage IV colorectal cancer, with specific attention paid to survival benefit and safety. METHOD: This was a retrospective review of all stage IV colon and rectal cancer patients in our tumour registry between 1991 and 2002. Data collected included patient demographics, presenting symptoms, detail from the hospital course including diagnostic data and operative management, complications and survival time (days). Survival analysis was performed to assess the effect of primary tumour resection on long-term survival. RESULTS: 109 patients were studied. Sixty-two (57%) patients (group I) underwent resection of the primary tumour, whereas 47 (43%) patients (group II) were managed without resection. Median survival times for groups I and II were 375 (IQR: 179-759) and 138 (IQR: 35-262) days respectively (P < 0.0001). After controlling for age, sex, tumour location and level of liver involvement as well as liver function, patients who underwent resection still survived longer (HR = 0.34, 95% CI: 0.21-0.55). CONCLUSION: Palliative resection of the primary tumour plays an essential role in the management of stage IV colorectal cancer. Resection can offer increased survival and is indicated in certain patients with incurable disease. Limited metastatic tumour burden of the liver was associated with better survival in such patients.

Temporal characteristics of slot machine play in recreational gamblers.

The present study examined the temporal characteristics of play exhibited by recreational slot machine players. 12 women (M = 24 yr., range 22-28) played a computerized version of a slot machine with probability of payoff, i.e., a winning spin, ranging from .2 to .6. Intertrial intervals or the time between the termination of one trial to the initiation of the next trial varied within subjects as a function of wins and losses. Winning trials were associated with larger intertrial intervals and losing trials with smaller intertrial intervals for 10 of the 12 women. No differences were found across probability levels between subjects. Results are discussed in terms of the post-reinforcement pause that occurs on specific schedules of reinforcement.

Functional analysis and treatment of inappropriate verbal behavior.

The present study examined the possible function of inappropriate verbal behavior of an adult man who had been diagnosed with both mental retardation and psychosis. Results of a functional analysis indicated that inappropriate verbal utterances were maintained by attention. An intervention consisting of the differential reinforcement of appropriate verbal behavior effectively reduced the inappropriate behavior.

Self-control in children with autism: response allocation during delays to reinforcement.

This study examined the use of a progressive-delay schedule of reinforcement to increase self-control and decrease disruptive behavior in children with autism. When initially given the choice between an immediate smaller reinforcer and a larger delayed reinforcer, all participants chose the smaller reinforcer. When access to the larger reinforcer required either no activity or engaging in a concurrent task during the delay, all participants demonstrated both self-control and preference for a response requirement. Disruptive behavior decreased during delays that required a concurrent task compared to sessions without an activity requirement.

A procedure to teach self-control to children with attention deficit hyperactivity disorder.

This study examined the use of a progressive delay procedure combined with verbal mediation to teach self-control to children with attention deficit disorder. Results showed that when participants were initially given the choice between an immediate smaller reinforcer and a larger delayed reinforcer, all participants chose the smaller reinforcer. When slight delays to obtain a larger reinforcer were instated in conjunction with intervening verbal activity, all participants demonstrated self-control regardless of the content of the verbal activity.

Unipedal stance testing as an indicator of fall risk among older outpatients.

OBJECTIVE: To test the hypothesis that a decreased unipedal stance time (UST) is associated with a history of falling among older persons. DESIGN: Fifty-three subjects underwent a standardized history and physical examination and three trials of timed unipedal stance. SETTING: The electroneuromyography laboratories of tertiary care Veterans Administration and university hospitals. SUBJECTS: Ambulatory outpatients 50 years and older referred for electrodiagnostic studies. OUTCOME MEASURES: UST and fall histories during the previous year. RESULTS: Twenty subjects (38%) reported falling. Compared with the subjects who had not fallen, those who fell had a significantly shorter UST (9.6 [SD 11.6] vs 31.3 [SD 16.3] seconds, using the longest of the three trials, p < .00001). An abnormal UST (<30sec) was associated with an increased risk of having fallen on univariate analysis and in a regression model (odds ratio 108; 95% confidence interval 3.8, >100; p < .007). The sensitivity of an abnormal UST in the regression model was 91% and the specificity 75%. When UST was considered age was not a predictor of a history of falls. CONCLUSIONS: UST of <30sec in an older ambulatory outpatient population is associated with a history of falling, while a UST of > or = 30sec is associated with a low risk of falling.

Teaching self-control to small groups of dually diagnosed adults.

The present study examined the use of a progressive delay procedure to teach self-control to two groups of dually diagnosed adults. When given a choice between an immediate smaller reinforcer and a larger delayed reinforcer, both groups chose the smaller reinforcer during baseline. During treatment, progressive increases in work requirements for gaining access to a larger reinforcer resulted in both groups selecting larger delayed reinforcers. The results are discussed with respect to increasing cooperative work behavior and self-control.

A computerized slot machine simulation to investigate the variables involved in gambling behavior.

The present paper describes a computerized slot machine simulation designed to examine many of the potential variables involved in gambling behavior. This program was created in Visual Basic Version 6.0 and is designed to run on any Windows 95 or higher equipped computer. The program allows for experimenter manipulation of probabilities of payoffs, visual display of potential winning symbols, exact sequences of wins and losses, as well as pose run time questions to the subject on prespecified trials. The program records data on a trial-by-trial basis to a text file for easy importation into many data analysis and statistical programs. Conceptual and experimental questions that may be addressed with the described program are also discussed.

Using a self-control training procedure to increase appropriate behavior.

The present study evaluated a technique for teaching self-control and increasing desirable behaviors among adults with developmental disabilities. Results showed that when participants were initially given the choice between an immediate smaller reinforcer and a larger delayed reinforcer, all participants repeatedly chose the smaller reinforcer. Concurrent fixed-duration/progressive-duration reinforcement schedules then were introduced in which initially both the smaller and larger reinforcers were available immediately. Thereafter, progressively increasing delays were introduced for the schedule associated with the larger reinforcer only. When initial short-duration requirements for access to the larger reinforcer were gradually increased, participants repeatedly selected the larger reinforcer, thereby demonstrating increased self-control.

Engaging in "illusory control" during repeated risk-taking.

Risk-taking behavior occurs when an individual chooses to engage in a game of chance. Although the outcomes of these games are completely random, many individuals believe that they can exercise some control over the outcomes. The present study examined the extent to which five undergraduate roulette players would pay additional money for opportunities to engage in an illusory activity that had no influence on the game's outcome, i.e., choosing random numbers rather than having the experimenter choose them. All five subjects engaged in this type of activity and the extent to which they did was linearly related to the player's winnings. These findings may suggest why people continue to gamble when the odds of winning are against them.