bluuebunny/crossref_metadata_2025 huggingface dataset:
Theoretical Formulation of Collision Rate and Collision Efficiency of Hydrodynamically Interacting Cloud Droplets in Turbulent Atmosphere
Authors: Wang Lian-Ping , Ayala Orlando , Kasprzak Scott E. , Grabowski Wojciech W.
Published: August 2005

A methodology for conducting direct numerical simulations (DNSs) of hydrodynamically interacting droplets in the context of cloud microphysics has been developed and used to validate a new kinematic formulation capable of describing the collision rate and collision efficiency of cloud droplets in turbulent air. The theoretical formulation is formally the same as the formulation recently developed for geometrical collision rate of finite-inertia, nonsettling particles. It is shown that its application to hydrodynamically interacting droplets requires corrections because of a nonoverlap requirement. An approximate method for correcting the kinematic properties has been developed and validated against DNS data. The formulation presented here is more general and accurate than previously published formulations that, in most cases, are some extension to the description of hydrodynamic–gravitational collision. General dynamic and kinematic representations of the properly defined collision efficiency in a turbulent flow have been discussed. In addition to augmenting the geometric collision rate, air turbulence has been found to enhance the collision efficiency because, in a turbulent flow, hydrodynamic interactions become less effective in reducing the average relative radial velocity. The level of increase in the collision efficiency depends on the flow dissipation rate. For example, the collision efficiency between droplets of 20 and 25 μm in radii is increased by 59% and 10% by air turbulence at dissipation rates of 400 and 100 cm2 s−3, respectively. It is also shown that hydrodynamic interactions lead to higher droplet concentration fluctuations. The formulation presented here separates the effect of turbulence on collision efficiency from the previously observed effect of turbulence on the geometric collision rate.
Evolution of a Florida Cirrus Anvil
Authors: Garrett T. J. , Navarro B. C. , Twohy C. H. , Jensen E. J. , Baumgardner D. G. , Bui P. T. , Gerber H. , Herman R. L. , Heymsfield A. J. , Lawson P. , Minnis P. , Nguyen L. , Poellot M. , Pope S. K. , Valero F. P. J. , Weinstock E. M.
Published: August 2005

This paper presents a detailed study of a single thunderstorm anvil cirrus cloud measured on 21 July 2002 near southern Florida during the Cirrus Regional Study of Tropical Anvils and Cirrus Layers–Florida Area Cirrus Experiment (CRYSTAL-FACE). NASA WB-57F and University of North Dakota Citation aircraft tracked the microphysical and radiative development of the anvil for 3 h. Measurements showed that the cloud mass that was advected downwind from the thunderstorm was separated vertically into two layers: a cirrus anvil with cloud-top temperatures of −45°C lay below a second, thin tropopause cirrus (TTC) layer with the same horizontal dimensions as the anvil and temperatures near −70°C. In both cloud layers, ice crystals smaller than 50 μm across dominated the size distributions and cloud radiative properties. In the anvil, ice crystals larger than 50 μm aggregated and precipitated while small ice crystals increasingly dominated the size distributions; as a consequence, measured ice water contents and ice crystal effective radii decreased with time. Meanwhile, the anvil thinned vertically and maintained a stratification similar to its environment. Because effective radii were small, radiative heating and cooling were concentrated in layers approximately 100 m thick at the anvil top and base. A simple analysis suggests that the anvil cirrus spread laterally because mixing in these radiatively driven layers created horizontal pressure gradients between the cloud and its stratified environment. The TTC layer also spread but, unlike the anvil, did not dissipate—perhaps because the anvil shielded the TTC from terrestrial infrared heating. Calculations of top-of-troposphere radiative forcing above the anvil and TTC showed strong cooling that tapered as the anvil evolved.
A Topographic Drag Closure Built on an Analytical Base Flux
Authors: Garner Stephen T.
Published: August 2005

Topographic drag schemes depend on grid-scale representations of the average height, width, and orientation of the subgrid topography. Until now, these representations have been based on a combination of statistics and dimensional analysis. However, under certain physical assumptions, linear analysis provides the exact amplitude and orientation of the drag for arbitrary topography. The author proposes a computationally practical closure based on this analysis.

Also proposed is a nonlinear correction for nonpropagating base flux. This is patterned after existing schemes but is better constrained to match the linear solution because it assumes a correlation between mountain height and width. When the correction is interpreted as a formula for the transition to saturation in the wave train, it also provides a way of estimating the vertical distribution of the momentum forcing. The explicit subgrid height distribution causes a natural broadening of the layers experiencing the forcing. Linear drag due to simple oscillating flow over topography, which is relevant to ocean tides, has almost the same form as for the stationary atmospheric problem. However, dimensional analysis suggests that the nonpropagating drag in this situation is mostly due to topographic length scales that are small enough to keep the steady-state assumption satisfied.
A Simulation of a Supercell Thunderstorm with Emulated Radiative Cooling beneath the Anvil
Authors: Markowski Paul M. , Harrington Jerry Y.
Published: August 2005

This note reports the preliminary results of an ongoing numerical study designed to investigate what effects, if any, radiative transfer processes can have on the evolution of convective storms. A pair of idealized three-dimensional simulations are conducted to demonstrate the potential dynamical importance of shortwave radiation reductions within the large shadows cast by storms. One of the simulations (the control) is run without surface physics and radiation. In the other simulation, radiative cooling due to cloud shading is emulated by prescribing a cooling rate to the skin temperature at any grid point at which cloud water was present overhead. The imposed skin cooling rate is consistent with past observations. Low-level air temperatures are coupled to the skin cooling in this second simulation by the inclusion of surface sensible heat fluxes using simple bulk aerodynamic drag laws (latent and soil heat fluxes are not included). Significant differences are observed between the two simulated storms, particularly in the evolution of the vertical vorticity field and gust fronts. The storm simulated with emulated cloud shading develops substantially weaker low-level rotation than the storm in the control simulation.
Sensitivity of the Simulated Monsoons of 1987 and 1988 to Convective Parameterization Schemes in MM5
Authors: Ratnam J. Venkata , Kumar K. Krishna
Published: August 2005

In this study the fifth-generation Pennsylvania State University–National Center for Atmospheric Research (PSU–NCAR) Mesoscale Model (MM5) version 3.5.2 was used to simulate the Indian summer monsoon during the two contrasting years of 1987 and 1988, a dry year and a wet year, respectively. Three different convection parameterization schemes of Betts–Miller–Janjic, Kain–Fritsch, and Grell were used to study the sensitivity of monsoon to cumulus effects. The model was integrated for a period of 6 months, starting from three different initial conditions of 0000 UTC on 1, 2, and 3 May of each year using the NCEP–NCAR reanalysis data as input. The 6-hourly reanalysis data were used to provide the lateral boundary conditions, and the observed weekly Reynolds sea surface temperature, linearly interpolated to 6 h, was used as the lower boundary forcing. The results show that all three cumulus schemes were able to simulate the interannual and intraseasonal variabilities in the monsoon with reasonable accuracy. However, the spatial distribution of the rainfall and its quantity were different in all the schemes. The Grell scheme underestimated the rainfall in both the years. The Kain–Fritsch scheme simulated the observed rainfall well during July and August, the peak monsoon months, of the year 1988 but overestimated the rainfall in June and September of 1988 and throughout the monsoon season of 1987. The Betts–Miller–Janjic scheme simulated less rainfall in the drought year of 1987 and overestimated the rainfall in June and July of 1988. The circulation patterns simulated by the Betts–Miller–Janjic and Kain–Fritsch schemes are comparable to the observed patterns.
High Clouds over Oceans in the ECMWF 15- and 45-Yr Reanalyses
Authors: Chevallier Frédéric , Kelly Graeme , Simmons Adrian J. , Uppala Sakari , Hernandez Angeles
Published: August 2005

The reanalysis programs of numerical weather prediction (NWP) centers provide global, comprehensive descriptions of the atmosphere and of the earth’s surface over long periods of time. The high realism of their representation of key NWP parameters, like temperature and winds, implies some realism for less emblematic parameters, such as cloud cover, but the degree of this realism needs to be documented.

This study aims to evaluate the high clouds over open oceans in the ECMWF 15- and 45-yr reanalyses. The assessment is based on a new 23-yr climatology of monthly frequencies of high-cloud occurrence retrieved from the infrared radiances measured by operational polar satellites. It is complemented by data from the International Satellite Cloud Climatology Project.

It is shown that the 45-yr ECMWF reanalysis dramatically improves on the previous 15-yr reanalysis for the realism of seasonal and interannual variations in high clouds, despite remaining systematic errors. More than 60% of the observed anomalies during the January 1979–February 2002 period over large oceanic basins are captured by the latest reanalysis. However the realism of the analyses in the areas and in the years with sparse observations appears to be poor. Consequently, the interannual variations may not be reliable before January 1979 in most parts of the world. Possible improvements of the handling of assimilated satellite observations before and after this date are suggested.
Impact of the Diurnal Cycle of Solar Radiation on Intraseasonal SST Variability in the Western Equatorial Pacific
Authors: Shinoda Toshiaki
Published: August 2005

The mechanism by which the diurnal cycle of solar radiation modulates intraseasonal SST variability in the western Pacific warm pool is investigated using a one-dimensional mixed layer model. SSTs in the model experiments forced with hourly surface fluxes during the calm–sunny phase of intraseasonal oscillation are significantly warmer than those with daily mean surface fluxes. The difference in two experiments is explained by upper-ocean mixing processes during nighttime. Surface warming during daytime creates a shallow diurnal warm layer near the surface (0–3 m), which can be easily eroded by surface cooling during nighttime. Further cooling, however, requires a substantial amount of energy because deeper waters need to be entrained into the mixed layer. Since the shallow diurnal layer is not formed in the experiment with daily mean surface fluxes, the SST for the hourly forcing case is warmer most of the time due to the diurnally varying solar radiation.

Sensitivity of the intraseasonal SST variation to the penetrative component of solar radiation is examined, showing that the diurnal cycle plays an important role in the sensitivity. Solar radiation absorbed in the upper few meters significantly influences intraseasonal SST variations through changes in amplitude of diurnal SST variation.
The Recurrence Time of Dansgaard–Oeschger Events and Limits on the Possible Periodic Component
Authors: Ditlevsen Peter D. , Kristensen Mikkel S. , Andersen Katrine K.
Published: August 2005

By comparing the high-resolution isotopic records from the Greenland Ice Core Project (GRIP) and the North Greenland Ice Core Project (NGRIP) ice cores, the common climate signal in the records has been approximately separated from local noise. From this, an objective criterion for defining Dansgaard–Oeschger (DO) events is achieved. The analysis identifies several additional short-lasting events, increasing the total number of DO events to 27 in the period 12–90 kyr before present (BP). The quasi-regular occurrence of the DO events could indicate a stochastic or coherent resonance mechanism governing their origin. From the distribution of waiting times, a statistical upper bound on the strength of a possible periodic forcing is obtained. This finding indicates that the climate shifts are purely noise driven with no underlying periodicity.
Arctic Surface, Cloud, and Radiation Properties Based on the AVHRR Polar Pathfinder Dataset. Part II: Recent Trends
Authors: Wang Xuanji , Key Jeffrey R.
Published: August 2005

Over the past 20 yr, some Arctic surface and cloud properties have changed significantly. Results of an analysis of satellite data show that the Arctic has warmed and become cloudier in spring and summer but has cooled and become less cloudy in winter. The annual rate of surface temperature change is 0.057°C for the Arctic region north of 60°N. The surface broadband albedo has decreased significantly in autumn, especially over the Arctic Ocean, indicating a later freeze-up and snowfall. The surface albedo has decreased at an annual rate of −0.15% (absolute). Cloud fraction has decreased at an annual rate of −0.6% (absolute) in winter and increased at annual rates of 0.32% and 0.16% in spring and summer, respectively. On an annual time scale, there is no trend in cloud fraction. During spring and summer, changes in sea ice albedo that result from surface warming tend to modulate the radiative effect of increasing cloud cover. On an annual time scale, the all-wave cloud forcing at the surface has decreased at an annual rate of –0.335 W m−2, indicating an increased cooling by clouds. There are large correlations between surface temperature anomalies and climate indices such as the Arctic Oscillation (AO) index for some areas, implying linkages between global climate change and Arctic climate change.
On Using Global Climate Model Simulations to Assess the Accuracy of MSU Retrieval Methods for Tropospheric Warming Trends
Authors: Kiehl Jeffrey T. , Caron Julie M. , Hack James J.
Published: August 2005

Climate model simulations of the latter part of the twentieth century indicate a warming of the troposphere that is equal to or larger than the warming at the surface, while satellite observations from the Microwave Sounding Unit (MSU) indicate little warming of the troposphere relative to surface observations. Recently, Fu et al. proposed a new approach to retrieving free tropospheric temperature trends from MSU data that better accounts for stratospheric cooling, which contaminates the tropospheric signal and leads to a smaller trend in tropospheric warming. In this study, climate model simulations are used as a self-consistent dataset to test these retrieval algorithms. The two methods of retrieving tropospheric temperature trends are applied to three climate model simulations of the twentieth century. The Fu et al. algorithm is found to be in very good agreement with the model-simulated tropospheric warming, indicating that it accurately accounts for cooling from the lower stratosphere.
When schooling fails
Authors: Jeffrey Craig , Jeffery Patricia , Jeffery Roger
Published: August 2005

Scholarly discussions of formal education in the global South are increasingly moving away from a narrow focus on human capital to consider the meanings that people attach to ‘being educated’. This article advances current debates on the social construction of educational value in South Asia by examining how educated Chamar (Dalit) young men reflect on their education in the face of poor occupational outcomes. Since the 1960s, Dalits’ investment in formal education in rural Uttar Pradesh (UP) has seen a marked rise, in part through emulation of higher castes. The pro–Dalit Bahujan Samaj Party (BSP) has also been instrumental in promoting a vision of empowerment through formal education and entry into white–collar employment. Our research in rural Bijnor district suggests that the most recent generation of high school and college graduates amongst the Chamars has failed to find salaried employment. Some young men respond to this exclusion by reaffirming their faith in the BSP's model of progress and establishing them–selves as local political figures (netas). Other young men voice a growing alienation from the BSP's vision of empowerment and speak of themselves as people ‘trapped’ by education. Nevertheless, both these sets of young men continue to value education as a source of ‘cultural distinction’, sign of their ‘modern’ status, and means of challenging caste–based notions of difference.
Challenging traditional authority
Authors: Froerer Peggy
Published: August 2005

This article is an examination of the relationship between traditional authority and the state, using a leadership dispute in a rural adivasi village as the ethnographic backdrop. The primary objective of the article is to examine how traditional authority continues to be reproduced in the context of local notions of political and cosmological legitimacy. It shows how the state can simultaneously buttress and transform traditional authority. By looking at the processes by which the state is experienced by local people, the article also illuminates the relationship that people have with lower–level state officials. Finally, the article sheds light on one way in which Hindu nationalism is making inroads into this particular adivasi community, and addresses the implications of how the RSS, acting as an extra–state power, is used to enforce accountability at a lower level.
Raiding the dreaded past
Authors: Zou David Vumlallian
Published: August 2005

This article looks at the diverse and rich representations of headhunting in north–east India, especially in the European translations of this tribal practice into ethnographic ‘writings’ during the late imperial age. Colonial concern and anxiety to ‘civilise’ the headhunter and ‘control’ this ‘savage’ practice in the hills is characterised by inner contradictions at every level of its articulation and operation. Headhunting is a history, a heritage, a rhetorical trope, a discursive practice, a philosophy, a returning gaze from the ‘other’, and a space for contesting masculinity. Moreover, it is a textual ‘record’ of colonial knowledge about vanishing societies for the benefit of the human sciences as well as frontier administrators in the region. But the vanishing object of salvage ethno–graphy itself appears to be a colonial construct of the anthropologising world and its legitimising representational practice. Headhunting is often neither the subject nor the object of study: it is a prolific site of discourse where the coloniser, the ethnographer, and even the local people engage in representing and translating the ‘other’ as well as them–selves, with diverse intentions.
The kinship, marriage and gender experiences of Tamil women in Sri Lanka's tea plantations
Authors: Philips Amali
Published: August 2005

The organisation of labour on tea plantations in Sri Lanka is based on a spatial, functional and ideological integration of kinship, marriage and ritual practices within a capitalist system of plantation production. This article foregrounds the household, kinship, and work experiences of women who constitute one half of the community of plantation workers of south Indian origin, to provide a balanced perspective to the discourse on south Indian kinship systems and practices. Its focus is on the reinforcement of kinship and gender inequalities within households and within the plantation labour organisation. In privileging women's experiences of kinship and marriage, this article adds to recent studies on kinship and gender in India that challenge the more traditional accounts based on androcentric perspectives, geographical generalisations, and the essentialisation of women.
Injuries in Female Soccer Players
Authors: Faude Oliver , Junge Astrid , Kindermann Wilfried , Dvorak Jiri
Published: August 2005

Background

In contrast to the high number of studies about soccer injuries in men, epidemiologic data in high-level female soccer players are scarce.

Purpose

Analysis of injury incidence in elite female soccer players.

Study Design

Descriptive epidemiology study.

Methods

There were 165 female soccer players (age, 22.4 ± 5.0 years) from 9 teams competing in the German national league, who were followed for one complete outdoor season. Their trainers documented the exposure to soccer on a weekly basis for each player, and the team physical therapists reported all injuries with regard to location, type, and circumstances of occurrence. An injury was defined as any physical complaint associated with soccer that limited sports participation for at least 1 day.

Results

There were 241 injuries sustained by 115 players (70%) reported; 39 injuries (16%) were owing to overuse, and 202 injuries (84%) were traumatic. Overall, 42% of the traumatic injuries occurred during training (2.8/1000 hours of training; 95% confidence interval, 2.2-3.4) and 58% during matches (23.3/1000 match hours; 95% confidence interval, 19.1-27.5); 102 of the traumatic injuries were caused by a contact situation, whereas 95 occurred without any contact. Most injuries (80%) were located at the lower extremities, concerning mainly the thigh (n = 44), knee (n = 45), and ankle (n = 43). Ankle sprain (n = 37) was the most often diagnosed injury. There were 51% minor injuries, 36% moderate injuries, and 13% major injuries. Eleven anterior cruciate ligament ruptures were observed during the season.

Conclusion

The results revealed a high injury incidence rate in games as well as a comparably low incidence rate during training. An important finding of this investigation was the frequent occurrence of anterior cruciate ligament ruptures. Preventive measures should thus focus on the high prevalence of anterior cruciate ligament tears, mostly occurring in noncontact situations.
Biochemical and Biomechanical Properties of Lesion and Adjacent Articular Cartilage after Chondral Defect Repair in an Equine Model
Authors: Strauss Eric J. , Goodrich Laurie R. , Chen Chih-Tung , Hidaka Chisa , Nixon Alan J.
Published: August 2005

Background

Chondral defects may lead to degradative changes in the surrounding cartilage, predisposing patients to developing osteoarthritis.

Purpose

To quantify changes in the biomechanical and biochemical properties of the articular cartilage adjacent to chondral defects after experimental defect repair.

Study Design

Controlled laboratory study.

Methods

Specimens were harvested from tissue within (lesion), immediately adjacent to, and at a distance from (remote area) a full-thickness cartilage defect 8 months after cartilage repair with genetically modified chondrocytes expressing insulin-like growth factor-I or unmodified, control chondrocytes. Biomechanical properties, including instantaneous Young's and equilibrium aggregate moduli, were determined by confined compression testing. Biochemical properties, such as water and proteoglycan content, were also measured.

Results

The instantaneous Young's modulus, equilibrium modulus, and proteoglycan content increased, whereas water content decreased with increasing distance from the repaired lesion. The instantaneous Young's and equilibrium moduli of the adjacent articular cartilage were 80% and 50% that of remote area samples, respectively, whereas water content increased 0.9% and proteoglycan content was decreased by 35%. No significant changes in biomechanical and biochemical properties were found either in the lesion tissue or in adjacent cartilage with genetic modification of the chondrocytes.

Conclusion

Articular cartilage adjacent to repaired chondral defects showed significant remodeling 8 months after chondral defect repair, regardless of whether genetically modified or unmodified cells were implanted.

Clinical Relevance

Changes in the biochemical and biomechanical properties of articular cartilage adjacent to repaired chondral defects may represent remodeling as part of an adaptive process or degeneration secondary to an altered distribution of joint forces. Quantification of these changes could provide important parameters for assessing progress after operative chondral defect repair.
Impact of Measurement Error in the Analysis of Bone Tunnel Enlargement after Anterior Cruciate Ligament Reconstruction
Authors: Webster Kate E. , Chiu James J. , Feller Julian A.
Published: August 2005

Background

Radiographic bone tunnel enlargement after anterior cruciate ligament reconstruction is frequently reported. The error associated with measuring tunnels on radiographs has not been established and may be substantial.

Hypothesis

Measurement error influences interpretation of bone tunnel enlargement.

Study Design

Cohort study (Diagnosis); Level of evidence, 2.

Methods

Radiographs and clinical outcomes were obtained from 76 subjects who had undergone hamstring tendon anterior cruciate ligament reconstruction. Tunnel enlargement was determined by measuring the widths of the femoral and tibial tunnels with a digital caliper in lateral and anteroposterior radiographs. Measurements were corrected for magnification; the percentage change in tunnel widths was recorded relative to the diameters drilled at surgery. One examiner measured all radiographs and repeated the procedure for 20 randomly selected radiographs 12 months later. A second examiner measured the same 20 radiographs. Intraclass correlation coefficients and 95% confidence intervals for intrarater and interrater measurement errors were calculated. Confidence intervals were used to divide subjects into 2 groups according to whether bone tunnel enlargement was within (unenlarged tunnel group) or greater than (enlarged tunnel group) the 95% confidence interval for measurement error; clinical comparisons between these groups were made for each view of tibial and femoral tunnels.

Results

Measurement errors for tunnel enlargement ranged from 17% to 26% for intrarater measurements and 24% to 38% for interrater measurements. For the lateral view of the tibial tunnel, there was a significant positive association between tunnel enlargement and anterior knee laxity. There was no relationship between femoral tunnel enlargement and anterior knee laxity.

Conclusion

There was considerable error associated with bone tunnel measurement. A relationship between tibial tunnel enlargement on the lateral radiograph and anterior knee laxity was evident once enlargement was defined as a change that exceeded measurement error.

Clinical Relevance

Measurement of bone tunnels on radiographs is useful for interpreting large changes; caution should be used when small changes are observed.
Suture Plication, Thermal Shrinkage, and Sclerosing Agents
Authors: Aneja Arun , Karas Spero G. , Weinhold Paul S. , Afshari Hessam M. , Dahners Laurence E.
Published: August 2005

Background

Shortening or tightening of dense, collagenous tissues is often desirable in the treatment of laxity.

Purpose

To compare the effect of stress-protection suture, radiofrequency thermal shrinkage combined with stress-protection suture, and a 5% sodium morrhuate sclerosing injection on the length and biomechanical strength of the rat patellar tendon.

Hypothesis

Sclerosing agents will increase tendon mechanical strength. Thermal shrinkage combined with stress-protection suture and stress-protection suture only will cause a short-term decrease in tendon strength. All 3 methods will produce equivalent shortening of the tendon.

Study Design

Controlled laboratory study.

Methods

Forty-six female retired breeder rats were split into 4 groups, each receiving 1 of the 3 aforementioned treatments plus a control group that received a saline injection. After 4 weeks’ survival, the length and biomechanical properties of the patellar tendons were measured and compared to the contralateral untreated tendon.

Results

Rats treated with stress-protection suture had shorter tendons. Radiofrequency thermal shrinkage combined with stress-protection suture yielded tendons that were both shorter and stronger than were the untreated contralateral tendons. The sodium morrhuate-injected tendons were stronger whereas the saline-treated tendons were weaker than were their respective untreated contralateral tendons.

Conclusion

Surgical stress-protection suture without radiofrequency shrinkage is most effective at shortening the length of the rat patellar tendon, whereas radiofrequency thermal shrinkage combined with stress-protection suture as well as sodium morrhuate are effective at increasing the strength of rat patellar tendons.

Clinical Relevance

Judicious use of thermal shrinkage in combination with stress protection may improve ligament strength and decrease laxity.
Articular Cartilage Repair in Soccer Players with Autologous Chondrocyte Transplantation
Authors: Mithöfer Kai , Peterson Lars , Mandelbaum Bert R. , Minas Tom
Published: August 2005

Background

The ability of autologous chondrocyte transplantation to produce and maintain an effective articular cartilage repair under high mechanical demands has not been investigated.

Hypothesis

Autologous chondrocyte transplantation provides a reliable and durable repair of full-thickness knee articular cartilage lesions in high-demand athletes.

Study Design

Case series; Level of evidence, 4.

Methods

A total of 45 soccer players were evaluated 41 ± 4 months after autologous chondrocyte transplantation for their ability to return to soccer, the timing of their return, skill level, and functional outcome rating by the Tegner activity rating scale score and Brittberg score. The factors influencing the return to sport were analyzed.

Results

Of these players, 72% reported good to excellent results, with significant overall improvement of Tegner activity rating scale scores; 33% returned to soccer, including 83% of competitive-level players and 16% of recreational players. Of the returning players, 80% returned to the same skill level and 87% maintained their ability to play soccer at 52 ± 8 months postoperatively. Players who successfully returned to soccer were significantly younger and had a shorter preoperative duration of symptoms than did patients who did not return to the sport. Concomitant adjuvant procedures did not adversely affect the ability to return to soccer.

Conclusion

Repair of knee articular cartilage lesions by autologous chondrocyte transplantation in high-performance athletes is particularly successful in younger, competitive athletes with limited preoperative intervals.
Revision Anterior Cruciate Ligament Reconstruction Using a 2-Stage Technique with Bone Grafting of the Tibial Tunnel
Authors: Thomas Neil P. , Kankate Raghu , Wandless Felicity , Pandit Hemant
Published: August 2005

Background

Revision anterior cruciate ligament surgery is often considered a salvage procedure with limited goals. However, this limitation need not be the case. Similar to primary reconstruction, the goal should be to choose an appropriate graft and place it in an anatomical position in a good quality bone. The issue of good quality bone seems to have been ignored.

Hypothesis

A 2-stage anterior cruciate ligament revision reconstruction with bone grafting of the tibial tunnel and the use of a different femoral tunnel will produce measured knee laxity and International Knee Documentation Committee scores similar to a primary anterior cruciate ligament reconstruction.

Study Design

Case control study; Level of evidence, 3.

Methods

This prospective study involved 49 consecutive 2-stage anterior cruciate ligament revisions (group R) performed by a single surgeon from 1993 to 2000. Two-stage revision surgery was performed if the tibial tunnel from a previous reconstruction surgery would overlap (either partially or fully) the correctly placed revision tunnel. The first stage consisted of removal of the old graft and interfering metalwork, together with bone grafting of the tibial tunnel. After ensuring adequate bone graft incorporation using computed tomography scan, the second stage revision was undertaken. This stage comprised harvesting the autograft, its anatomical placement, and its adequate fixation. The results were compared with the results of a matched group of patients with primary anterior cruciate ligament reconstruction (group P).

Results

In group R, as meniscal and chondral lesions were more common, the International Knee Documentation Committee scores were lower than those of group P (61.2 for group R and 72.8 for group P; P =. 006). Objective laxity measurement was similar in both groups (1.36 mm for group R and 1.2 mm for group P; P =. 25).

Conclusion

This study establishes that the laxity measurements achieved with a 2-stage revision anterior cruciate ligament reconstruction can be similar to those achieved after primary anterior cruciate ligament reconstruction, although the International Knee Documentation Committee rating is lower.
Meaning and Explanations of Mental Illness
Authors: Dixit Shikha
Published: August 2005

The notion of mental illness may be closely related to the social values pertinent in any social context. The meaning of mental illness rooted in everyday social psychological processes may be different from scientific and clinical understanding. In order to examine the common meaning of mental illness, the relationship between individual knowledge and implicit social knowledge needs to be explored. This can be achieved by studying the social representation of mental illness. This paper provides an understanding of the content of social representation of mental illness among a group of engineering students, and extends the findings to the broader social context of educated urban middle class youth. A qualitative study was conducted within the theoretical context of the social representations framework. The findings revealed that social representation of mental illness was structured in terms of social understanding of the causes and consequences of mental illness. Further, mental illness derived its meaning from the expectations and norms of society. Mental illness was generally labelled as a form of social deviance and viewed as including an element of volition. The social definition of mental illness appeared to be rooted in the social value that non–normative behaviours that are not in line with the expectations of society are related to mental illness. An interesting feature that was observed was the use of narratives to explain the meaning of mental illness.
Acculturation Attitudes and Adaptation among Portuguese Immigrants in Germany
Authors: Neto FÉlix , Barros JosÉ , Schmitz Paul G.
Published: August 2005

This study aims to understand preferences in acculturation strategies among Portuguese immigrants in Germany. The sample comprised 118 adults (mean age 41.9 years; SD 11.5). The average length of residence in Germany was 20.4 years (SD 9.1). Responses to the questionnaire revealed that integration was the most preferred acculturation strategy. Subjects who adopted an integration strategy manifested greater acculturation experience with German culture than those who adopted separation. Subjects who chose integration and separation strategies did not differ in their degree of cultural maintenance. Immigrants who chose an integration mode experienced lower levels of social adaptation difficulties than those who favoured a separation mode, but these two strategies did not reveal different levels of psychological adaptation. Understanding the complex relationships between demographic, intercultural and psychosocial adjustment factors, and acculturation strategies can help social scientists develop and apply adequate intervention strategies and give suggestions for the development of adequate sociopolitical acculturation programmes.
Parent–Adolescent Relationships in the Context of Interpersonal Disagreements
Authors: Kapadia Shagufa , Miller Joan
Published: August 2005

The paper is based on a study that aims to understand adolescent–parent relationships in the context of interpersonal disagreements. The issue of disagreements or disputes between parents and adolescents is of interest because of its relevance to understanding universal versus culturally variable features of adolescent development and parent–adolescent relationships. The study focused on understanding the dynamics of dispute resolution in Indian families, particularly the strategies of resolution and the patterns of reasoning involved in the same. A sample of 60 adolescents and their parents from nuclear, Hindu, upper middle class urban families was interviewed to examine their understanding of adolescence, perceptions of mutual expectations, and views on resolving two hypothetical disagreements on marriage partner selection and heterosexual relationships. The findings revealed little acknowledgement of adolescence as a clearly demarcated stage of development. In general, both adolescents and parents had positive perceptions of themselves as adolescents and parents of adolescents. Resolution of disagreements included the active involvement of all parties. Mutual accommodation was the most commonly used strategy for resolving disagreements. Adolescents endorsed resolutions favouring compromise with parents, based on the reasoning that parents had the welfare of their children in mind. Parents on their part adopted an open–minded attitude toward the adolescents’ activities and allowed them space to articulate their own views. A primary motivation to sustain the values of family interdependence and harmony was clearly reflected in the sample.
Identifying a Framework for Initiating, Sustaining and Managing Innovations in Schools
Authors: Sharma Rajeev
Published: August 2005

Innovations in educational organisations have not been researched as intensely as business and industrial organisations in India. If innovations are to flourish in schools, it is critical that the mechanisms which can sustain and encourage them be understood clearly. The present study examined the innovations adopted in four schools and thereby uncovered the system and processes which were conducive to their sustenance. The four schools located in different parts of the country, have utilised a range of innovations at school level in the areas of pedagogy, curriculum, evaluation, administration and resource mobilisation. Findings indicated the important role of leadership in adopting innovations in schools. Subsequently, openness in vertical and horizontal communication and establishing a wide network with individuals and institutions outside also appeared to be critical. The innovative schools had also developed a well–defined and documented system of review and monitoring, and mobilising community support. These schools had established pro–cedures for teachers’ training and growth, and instituted decentralised and participative systems of management. Implications of these findings for management of innovations in schools are discussed.
The Impact of Hospitalists on the Cost and Quality of Inpatient Care in the United States: A Research Synthesis
Authors: Coffman Janet , Rundall Thomas G.
Published: August 2005

There is substantial disagreement regarding the impact of hospitalists on costs, quality, and satisfaction with inpatient care. The authors reviewed 21 evaluations of the use of hospitalists in U.S. hospitals. Most evaluations found that patients managed by hospitalists had lower total costs or charges than patients in comparison groups and that these savings were achieved primarily by reducing length of stay. Most evaluations found no statistically significant differences in quality of care or satisfaction. However, lack of random assignment limits the ability to draw causal inferences from many of the evaluations. All randomized studies were conducted in teaching hospitals, raising questions as to the generalizability of findings to nonteaching hospitals. Further research is needed to better identify the mechanisms by which hospitalists reduce length of stay and to ascertain which types of hospitalist programs are most effective and which patients are most likely to benefit.
Employment-Based Health Insurance: Analysis of Rural-Urban Differences in One State
Authors: Ketsche Patricia
Published: August 2005

This study estimates the propensity of firms to offer health insurance in a simultaneous equation model to control for the endogeneity between wages and health insurance. Previous research finds differences in rural and urban employer behavior with respect to health insurance benefits fully explained by differences in wages and firm size. In contrast, this study finds residual unexplained differences in the propensity to offer coverage that may be attributable to differences in plan supply, plan distribution, or differences in availability of substitutes for coverage (safety net care). Rural worker participation in offered coverage is more responsive to wage level than is the participation decision of urban workers. Together, these results imply that some of the differences in health insurance coverage rates for rural workers could be amenable to policy interventions.
An Empirical Assessment of High-Performing Medical Groups: Results from a National Study
Authors: Shortell Stephen M. , Schmittdiel Julie , Wang Margaret C. , Li Rui , Gillies Robin R. , Casalino Lawrence P. , Bodenheimer Thomas , Rundall Thomas G.
Published: August 2005

The performance of medical groups is receiving increased attention. Relatively little conceptual or empirical work exists that examines the various dimensions of medical group performance. Using a national database of 693 medical groups, this article develops a scorecard approach to assessing group performance and presents a theory-driven framework for differentiating between high-performing versus low-performingmedical groups. The clinical quality of care, financial performance, and organizational learning capability of medical groups are assessed in relation to environmental forces, resource acquisition and resource deployment factors, and a quality-centered culture. Findings support the utility of the performance scorecard approach and identification of a number of key factors differentiating high-performing from low-performing groups including, in particular, the importance of a quality-centered culture and the requirement of outside reporting from third party organizations. The findings hold a number of important implications for policy and practice, and the framework presented provides a foundation for future research.
Health-related quality of life in patients with pulmonary arterial hypertension
Authors: Taichman Darren B , Shin Jennifer , Hud Laryssa , Archer-Chicko Christine , Kaplan Sandra , Sager Jeffery S , Gallop Robert , Christie Jason , Hansen-Flaschen John , Palevsky Harold
Published: August 2005

Background

Improved outcomes with expanding treatment options for patients with pulmonary arterial hypertension present the opportunity to consider additional end-points in approaching therapy, including factors that influence health-related quality of life. However, comparatively little is known about health-related quality of life and its determinants in patients with pulmonary arterial hypertension.

Methods

Health-related quality of life was evaluated in a cross sectional study of 155 outpatients with pulmonary arterial hypertension using generic and respiratory-disease specific measurement tools. Most patients had either World Health Organization functional Class II or III symptoms. Demographic, hemodynamic and treatment variables were assessed for association with health-related quality of life scores.

Results

Patients with pulmonary arterial hypertension suffered severe impairments in both physical and emotional domains of health-related quality of life. Patients with idiopathic ("primary") pulmonary arterial hypertension had the best, and those with systemic sclerosis the worst health-related quality of life. Greater six-minute walk distance correlated with better health-related quality of life scores, as did functional Class II versus Class III symptoms. Hemodynamic measurements, however, did not correlate with health-related quality of life scores. No differences in health-related quality of life were found between patients who were being treated with calcium channel antagonists, bosentan or continuously infused epoprostenol at the time of quality of life assessment.

Conclusion

Health-related quality of life is severely impaired in patients with pulmonary arterial hypertension and is associated with measures of functional status. Specific associations with impaired health-related quality of life suggest potential areas for targeted intervention.
Which resources should be used to identify RCT/CCTs for systematic reviews: a systematic review
Authors: Crumley Ellen T , Wiebe Natasha , Cramer Kristie , Klassen Terry P , Hartling Lisa
Published: August 2005

Background

Systematic reviewers seek to comprehensively search for relevant studies and summarize these to present the most valid estimate of intervention effectiveness. The more resources searched, the higher the yield, and thus time and costs required to conduct a systematic review. While there is an abundance of evidence to suggest how extensive a search for randomized controlled trials (RCTs) should be, it is neither conclusive nor consistent. This systematic review was conducted in order to assess the value of different resources to identify trials for inclusion in systematic reviews.

Methods

Seven electronic databases, four journals and Cochrane Colloquia were searched. Key authors were contacted and references of relevant articles screened. Included studies compared two or more sources to find RCTs or controlled clinical trials (CCTs). A checklist was developed and applied to assess quality of reporting. Data were extracted by one reviewer and checked by a second. Medians and ranges for precision and recall were calculated; results were grouped by comparison. Meta-analysis was not performed due to large heterogeneity. Subgroup analyses were conducted for: search strategy (Cochrane,Simple,Complex,Index), expertise of the searcher (Cochrane, librarian, non-librarian), and study design (RCT and CCT).

Results

Sixty-four studies representing 13 electronic databases met inclusion criteria. The most common comparisons were MEDLINE vs. handsearching (n = 23), MEDLINE vs. MEDLINE+handsearching (n = 13), and MEDLINE vs. reference standard (n = 13). Quality was low, particularly for the reporting of study selection methodology. Overall, recall and precision varied substantially by comparison and ranged from 0 to 100% and 0 to 99%, respectively. The trial registries performed the best with median recall of 89% (range 84, 95) and median precision of 96.5% (96, 97), although these results are based on a small number of studies. Inadequate or inappropriate indexing was the reason most cited for missing studies.ComplexandCochranesearch strategies (SS) performed better thanSimpleSS.

Conclusion

Multiple-source comprehensive searches are necessary to identify all RCTs for a systematic review, although indexing needs to be improved. Although trial registries demonstrated the highest recall and precision, theCochraneSS or aComplexSS in consultation with a librarian are recommended. Continued efforts to develop CENTRAL should be supported.