The effect of tennis racket string vibration dampers on racket handle vibrations and discomfort following impacts.

In this study, we evaluated the effect of the use of tennis racket string vibration dampers on racket handle vibrations, and perceptions of hand and arm discomfort experienced by tennis players owing to stationary racket impacts. Twenty tennis players (10 males, 10 females) aged 18-29 years volunteered for the study. Two different racket models were impacted at the geometric centre of the racket face and 100 mm distal to the centre both with and without string vibration dampers in place. The participants could neither see nor hear the impacts, and they indicated their discomfort immediately after each impact using a visual analogue scale. An analysis of variance (2 x 2 x 2 factorial) was performed on the scaled discomfort ratings with the factors damping condition, racket type and impact location. No significant differences in discomfort ratings between damped and undamped impacts or between the two racket types were found. Also, central impacts were found to be more comfortable than impacts 100 mm distal to the centre (P< 0.05). There were no significant interaction effects. Vibration traces from an accelerometer mounted on the racket handle revealed that string vibration dampers quickly absorbed high-frequency string vibration without attenuating the lower-frequency frame vibration. In conclusion, we found no evidence to support the contention that string vibration dampers reduce hand and arm impact discomfort.     

The Douglas County Model in Western Colorado

ABSTRACT

In 2012 the Marmot Library Network implemented the Douglas County Library Model of ebook collection and circulation. By 2014 Marmot had loaded 838 ebooks purchased direct from publishers and independent authors to an Adobe Content Server, and made them available in an open source discovery layer based on VuFind. In late 2015, after 3 years of disappointing circulation and tedious acquisition processes, Marmot decided to move some of this collection to OverDrive and abandon the local ACS. This article reports lessons learned from that experiment.

Column Editor’s Note This column focuses on formal collaboration and networking among libraries through consortia. It offers in-depth examinations of issues facing modern library consortia including (but not limited to) e-resource licensing, ebooks, next generation integrated library systems, shared print programs, shared digital repositories, governance, cooperative services and other relevant topics. Contributions are accepted for this column and must be submitted to George Machovec (george@coalliance.org). Contact the column editor for suggested topics, deadlines and formatting.     

NEWS AND NOTES

The purpose of this column is to keep religious educators abreast of the relevant significant research in the general field of psychology. Its implications for methods and materials in religious education are clear. Religious educators may well take advantage of every new finding in scientific research.

Bach abstract or group is preceded by an evaluation and interpretative comment, which aims to guide the reader in understanding the research reported.

All of these abstracts are from PSYCHOLOGICAL ABSTRACTS, and used by permission of that periodical. The abstract number is Volume 29, Number 1, February, 1955.     

Acute Exposure of College Basketball Players to Moderate Altitude: Selected Physiological Responses

Ten basketball players and two coaches ([Vdot]O₂ max = 51.08 ml/kg · min) were studied at their place of residence in Chadron, Nebraska (1,000 m, P_B = 661 mm Hg), and 6 days later in Laramie, Wyoming (2,200 m, P_B = 584 mm Hg). Subjects rode the bicycle ergometer through several submaximal workloads until voluntary exhaustion. Laramie tests took place within 8 hours after arrival and at the same time of day as the Chadron tests. Submaximal heart rate, oxygen consumption, pulmonary ventilation, carbon dioxide production, respiratory quotient, and perceived exertion were not significantly altered by the altitude change; however, ventilatory equivalent was significantly higher in Laramie (p < .05). The hypoxia-induced decrease in the anaerobic threshold ( workload = 906 kpm/min at both sites) which was hypothesized was not observed. Likewise, resting hematocrit and hemoglobin were not affected by the 1,200 m altitude increment (44.88 vs. 44.53% and 15.39 vs. 15.01 gm%, respectively). Maximum aerobic power, heart rate, and ventilation were not statistically significant. Maximum ventilatory equivalent increased and vital capacity decreased significantly in Laramie. In general, basketball players with moderately high aerobic power who reside at an altitude of 1,000 m do not display the hypoxic response to an altitude of 2,200 m expected of sea level residents and aerobically trained athletes.     

Identifying substance abusing delivering women: consequences for child maltreatment reports

OBJECTIVE: The major objective was to determine how and the extent to which SB2669, which requires the identification of substance abusing delivering women, affected the number of children reported for abuse or neglect in several California counties. METHOD: A monthly time-series model from April 1988 to December 1995 was constructed. The idea underlying the model was that month-to-month changes in the number of child maltreatment reports was a response to the presence of SB2669 in addition to various demographic, social, and economic factors. By separately estimating each county's number of reports, it was assumed that SB2669 did not necessarily affect each county's reports by the same amount, perhaps partially because of different counties' implementation strategies or general policies. Our sampling size consisted of seven high prevalence counties. RESULTS: The results suggest that the effects of SB2669 on the number of child maltreatment reports are mixed. On an aggregate level, all else constant, and at least for a few years after the passage of SB2669, SB2669 is associated with a decrease in child maltreatment reports in two of the participating counties. This decrease may be due to conscientious implementation of the legislation in these counties. This mixed finding is expected mainly because SB2669, although mandated, was never enforced. Moreover, from the process component of the study we learned that the implementation practices of this legislation vary substantially between and even within counties' hospitals. CONCLUSIONS/FUTURE DIRECTIONS: A decrease in maltreatment reports in the presence of SB2669 is not necessarily the most desirable outcome in the light of what we know about the relationship between substance abuse and child maltreatment. Law makers need to rethink the purpose of the law and provide the necessary language, tools and training to ensure that the goals of identifying substance abusing mothers and their families are met. Provisions also need to be made that somehow enforce this legislation. These provisions could lessen county-level and hospital-level variability in implementing the law.     

Effects of Item Wording on Sex Bias

This study examined the effects of gender-related item-wording changes on the performance of male and female examinees. Mathematics word problems and English language items were created in neuter, male, and female versions. Items were administered to randomly equivalent samples of about 300 high school juniors and seniors. Loglinear analysis was used to assess the impact of item gender and its interaction with examinee sex on the difficulty and discrimination of each item in each context. No items were found to have sex bias in either context. Mathematics items did not have different difficulty or discrimination in the three gender versions. Neither mathematics nor English items had different discrimination levels in the three gender-related versions. Some English items, however, were found to have different difficulty levels in the three gender-related versions. These difficulty differences were not systematic." none of the three gender versions appeared consistently more or less difficult than the others.     

Should Tougher Basic Skills Requirements Be Viewed as a Means of Strengthening the Teaching Force?

The study assesses the criterion-related validity of one state's set of basic skills requirements for teacher licensure. Though all 186 participants met the basic skills requirements in place when enrolled as teacher education students, the PPST Reading scores of 77 participants and the PPST Mathematics scores of 67 do not meet the state's current requirements. The magnitude of correlations between the participants' basic skills scores and their performance in student teaching provides no criterion-related support for the current requirements, and the correlations involving reading and mathematics raise questions regarding the minimal competency assumption that positive relationships exist between teaching performance and scores below the qualifying levels on basic skills tests.