High-impact Group Research Articles

Early citation counts correlate with accumulated impact

The present paper addresses the objective of developing forward indicators of research performance using bibliometric information on the UK science base. Most research indicators rely primarily on historical time series relating to inputs to, activity within and outputs from the research system. Policy makers wish to be able to monitor changing research profiles in a more timely fashion, the better to determine where new investment is having the greatest effect. Initial (e.g. 12 months from publication) citation counts might be useful as a forward indicator of the long-term (e.g. 10 years from publication) quality of research publications, but - although there is literature on citation-time functions - no study to evaluate this specifically has been carried out by Thomson ISI or any other analysts. Here, I describe the outcomes of a preliminary study to explore these citation relationships, drawing on the UK National Citation Report held by Evidence Ltd under licence from Thomson ISI for OST policy use. Annual citation counts typically peak at around the third year after publication. I show that there is a statistically highly significant correlation between initial (years 1-2) and later (years 3-10) citations in six research categories across the life and physical sciences. The relationship holds over a wide range of initial citation counts. Papers that attract more than a definable but field dependent threshold of citations in the initial period after publication are usually among the top 1p (the most highly cited papers) for their field and year. Some papers may take off slowly but can later join the high impact group. It is important to recognise that the statistical relationship is applicable to groups of publications. The citation profiles of individual articles may be quite different. Nonetheless, it seems reasonable to conclude that leading indicators of research excellence could be developed. This initial study should now be extended across a wider range fields to test the initial outcomes: earlier papers suggest the model holds in economics. Additional statistical tests should be applied to explore and model the relationship between initial, later and total citation counts and thus to create a general tool for policy application.

The Dose of Exposure and Prevalence Rates of Post Traumatic Stress Disorder in a Sample of Turkish Children Eleven Months After the 1999 Marmara Earthquakes

Since Turkey is a centrally prime earthquake zone, Turkey’s children are at risk for developing Post Traumatic Stress Disorder (PTSD) caused by earthquake exposures and threats of anticipated earthquakes. Given the gaps in the literature and the risk to children living in Turkey, the present study was undertaken to investigate the severity and prevalence of PTSD in 4th and 5th grade Turkish children after the notorious 1999 earthquakes in the city of Sakarya. Data were collected in May 2000. The research focus was to compare results between high-impact trauma and low-impact trauma groups according to percentage, severity and the frequency of PTSD diagnosis. Group means were compared for mild, moderate, severe and very severe categories of PTSD diagnosis. High and low impact groups were not significantly different in any category; the number of children who met the PTSD requirement was almost the same in both groups in number and severity.

The Effect of Competitive Sport Specific Activity Participation on Bone Mineral Density and Muscular Strength

1080 Athletes apparently self-select their sport of choice based on activities in which they excel. This natural self-selection may be in-part be based on their genetic physiological capabilities and/or the sport participation may enhance their pre-existing condition. Purpose: This study was designed to compare the relationship of bone mineral density, body composition, muscle function, and muscular strength to sport specific activities. Methods: Thirty-seven females (age 20.6 ± 3 yr; mass 63.9 ± 11.1 kg; height 167 ± 11.4 cm), representing high impact (volleyball, basketball, n = 9), medium impact (track, soccer, n = 9), low impact sports (swimming, n = 11), and a sedentary control group (n = 8) volunteered to undergo a DEXA scan, vertical jump tests, and knee extension/flexion exercise at 80 degrees/sec on a Cybex 6000 isokinetic dynamometer. All athletes completed at least two full seasons of intercollegiate sport competition, but most had competed for more than eight seasons in their respective sport. Measurements obtained from the DEXA assessment included bone mineral density, % fat, fat mass (FM), and fat-free mass (FFM). Results: Statistical analysis by ANOVA (P<.05) revealed significant differences between the high impact and low impact sport activity groups in bone mineral density. The high impact group also demonstrated greater strength and vertical jump performance (P<.05) than all other groups. Conclusion: Females who engage in high impact activity reveal differences in bone mineral density in many of the weight bearing skeletal structures, which seems to be associated with the enhanced muscular strength and power inherent in high-impact sport activity.

Induction of chondrocyte apoptosis following impact load.

To investigate the presence and extent of chondrocyte apoptosis following impact load of articular cartilage in an in vivo model. An in vivo animal model, using a pendulum device and New Zealand White rabbits, was designed to study the effects of impact load on the development of chondrocyte apoptosis. Animals were placed into either a High Impact group or a Low Impact group, and the right medial femoral condyle was impacted with a single impact load. A sham operation was performed on the left limb, and this cartilage served as the control. Academic medical center. New Zealand White rabbits (3 months). Impact load to the right medial femoral condyle. Three different methods were used to assess the presence and extent of chondrocyte apoptosis: 1) light microscopy (hematoxylin and eosin and terminal dUTP nick end labeling staining); 2) transmission electron microscopy; and 3) fluorescent microscopy with Hoechst 33342 staining. Secondary outcome measures included determination of the magnitude of impact force and time to peak force. Light microscopy demonstrated chondrocytes with changes consistent with apoptosis including condensed nuclei, deep eosinophilic cytoplasmic staining, and vacuolization within the impacted specimens. Terminal dUTP nick end labeling staining-stained specimens had a high degree of positively stained cells (60%) in both injured and uninjured specimens. Transmission electron microscopy of the impacted specimens demonstrated numerous chondrocytes with changes characteristic of apoptosis, including nuclear and cellular fragmentation, volume shrinkage, and cytoplasmic vacuolization. Eleven percent of the cells in the High Impact group had changes consistent with apoptosis, versus 3% for the low impact group and <1% for the sham specimens. The High Impact group received a statistically significant greater stress than the Low Impact group. Impact group (P < 0.05), and the average time to peak force was 0.021 seconds for each impact group. The current data strongly indicate that in vivo chondrocyte apoptosis can be stimulated by the application of a single, rapid impact load and that the extent of chondrocyte apoptosis is related to the amount of load applied. The contribution chondrocyte apoptosis makes to the development of posttraumatic arthritis following joint injury or intra-articular fracture still remains to be determined.

ADOLESCENT PHYSICAL ACTIVITY AND ADULT BONE MINERAL STATUS

Previous studies have shown a positive effect of physical activity on bone mineral density; however, most of these studies have used retrospective approaches and most did not differentiate physical activities based on impact loading on bone. PURPOSE The purpose of this study was to examine the relationship between self-reported physical activity during adolescence and adult bone mineral density (BMD) in 58 males from the Saskatchewan Growth and Development Study (SGDS). METHODS As part of the SGDS, detailed physical activity patterns were assessed annually from 1971 to 1973 (subjects were 14–16 years of age). An impact loading score was calculated based on the estimated loads of the various self-reported activities. An average score was then computed for these 3 years and subjects were placed into tertiles of physical activity impact categories: low; moderate; high. The original SGDS subjects were followed-up in 1997–98, when they were 38–40 years of age. At this time, BMD of the lumbar spine (LS) and femoral neck (FN) were measured using dual energy x-ray absorptiometry (Hologic 2000, array mode). RESULTS At follow-up, there were no differences among groups in adult height, weight, physical fitness, or physical activity scores (p < .05). BMD data were analyzed using a MANOVA procedure, and post-hoc comparisons done with a LSD test. Results showed a positive and significant difference (p < .05) between the low and the high impact group, and the moderate and high impact group at the FN. There were no differences at the LS. CONCLUSION The results of this study are consistent with others that have shown a significant relationship between adolescent physical activity and adult femoral BMD. These data support the theory that physical activity during adolescence is related to adult skeletal health. Supported by CIHR Grant MOP-57671

Salivary cortisol, posttraumatic stress symptoms, and general health in the acute phase and during 9-month follow-up

Background: Because traumatic events are unpredictable, there are few studies of psychobiological states immediately following such events. Our study aimed to determine the relation of salivary cortisol to psychologic distress immediately after a traumatic event and then during follow-up. Methods: Measurement of morning and evening salivary cortisol and ratings of psychologic distress (using the Impact of Events Scale [IES], the Post Traumatic Symptom Scale, and the General Health Questionnaire) were performed with 31 United Nations soldiers at three time points—5 days and 2 and 9 months—following a mine accident in Lebanon. Results: Five days after the accident, 15 subjects reported substantial posttraumatic distress according to the IES, as well as significantly lower morning and higher evening cortisol levels compared with the low-impact group. Within 9 months, the posttraumatic distress of the high-impact group was reduced, accompanied by an increase in morning and a decrease in evening cortisol levels. There were significant relationships between evening cortisol and all rating scales at the first and third time points. Conclusions: Subclinical posttraumatic stress following an adverse event can be measured biologically via salivary cortisol levels soon after the event.

Successful is Innovation: The Contingent Contributions of Innovation Characteristics and Implementation Process

This paper unifies two apparently competing theories of information systems (IS) implementation by developing a model in which the contributions of innovation characteristics and implementation process theories are contingent upon the implementation context. To do this, we identify the different assumptions regarding the implementation context implicit in the two theories and, based on these differences, develop a contingent model within which to integrate the two theories. A partial test of the model within one particular context is reported using data collected from the end-users of an IS innovation introduced in a State health system in Australia. As hypothesized, we find that, within the context, characterized by high individual level impact and low group level impact, the contribution of innovation characteristics to implementation success is higher than that of implementation process.

Successful IS innovation: the contingent contributions of innovation characteristics and implementation process

This paper unifies two apparently competing theories of information systems (IS) implementation by developing a model in which the contributions of innovation characteristics and implementation process theories are contingent upon the implementation context. To do this, we identify the different assumptions regarding the implementation context implicit in the two theories and, based on these differences, develop a contingent model within which to integrate the two theories. A partial test of the model within one particular context is reported using data collected from the end-users of an IS innovation introduced in a State health system in Australia. As hypothesized, we find that, within the context, characterized by high individual level impact and low group level impact, the contribution of innovation characteristics to implementation success is higher than that of implementation process.

Does prolonged high-impact activity contribute to later urinary incontinence? A retrospective cohort study of female olympians

To determine whether women engaged in strenuous, provocative exercise are more likely to be incontinent in future life than similarly fit women who participated in less provocative exercise. In this retrospective cohort study, female American Olympians who competed in swimming (low-impact group) and in gymnastics and track and field (high-impact group) between 1960 and 1976 completed a structured questionnaire. Primary outcome measures included the prevalence of the symptoms of stress and urge incontinence. Statistical analyses of results included chi2, Fisher exact test, two-tailed t tests, Wilcoxon rank sum test, and stepwise multiple logistic regression. P < .05 was considered significant. One hundred four women responded (response rate 51.2%). High-impact athletes were older (46.2 compared with 42.4 years) and were more likely to report incontinence when they were doing their sport as Olympians (35.8% compared with 4.5%) than low-impact athletes; low-impact athletes were more likely to be parous (83.3% compared with 60.7%). There was no difference in the prevalence of the symptom of stress incontinence between the high- versus low-impact groups: any incontinence, 41.1% compared with 50%; daily or weekly incontinence, 10.7% compared with 8.3%; and incontinence that bothered them moderately or greatly, 10.7% compared with 4.2%. With our sample size, this study had 80% power to detect a fourfold difference in daily or weekly incontinence between groups, but only a 30% power to detect a twofold difference, given a baseline prevalence of 10%. When age, body mass index (BMI), parity, Olympic sport group, and incontinence during Olympic sport were entered into stepwise logistic regression analyses, only BMI was significantly associated with regular stress or urge incontinence symptoms. Participation in regular, strenuous, high-impact activity when younger did not predispose women to a markedly higher rate of clinically significant urinary incontinence in later life.