Subsequent Time Periods Research Articles

The 1989 Dallas Conference on Morbidity and Mortality in Dialysis

I will attempt to recall, as best as my memory allows, what we learned from the 1989 Dallas Conference on Morbidity and Mortality and Prescription of Dialysis. These thoughts and opinions are my remembrance in the subsequent time period and therefore subject to the limitations of recall. Opinions expressed are my personal beliefs and cannot be verified by hardcore scientific data. Accept the thought process on the basis of recollection and my individual assessment of the issues discussed. It is surprising to me, in retrospect, what has occurred in the past 50 yr. It really is the history of clinical dialysis and kidney transplantation. Many of you may not be familiar with some of the earlier events, so I cover them briefly by decades. It will be difficult for many of us to realize that there were no self-defined nephrologists in the early part of the 1960s but only renal physiologists in some medical schools. The exceptions to this arrangement were led by a few brave pioneers, such as John Merrill in Boston, Belding Scribner in Seattle, and George Schreiner in Washington, DC. These men ignored the scorn of their academic colleagues and actually looked after patients with renal failure. The early effort of these individuals showed that it was possible to have patients recover from acute renal failure or even survive if their condition were chronic. Their results were exciting, capturing the public interests and making the cover of many national magazines, so the Public Health Service, in the mid-1960s, decided to offer 5-yr grants to determine whether chronic dialysis could be applied to the population at large. We obtained one of those grants in 1967 in Dallas. Finally, to close out the decade, a few courageous souls went into private practice as nephrologists, which became a board-certified specialty …

A comparative analysis of hotspot identification methods

The identification of crash hotspots is the first step of the highway safety management process. Errors in hotspot identification may result in the inefficient use of resources for safety improvements and may reduce the global effectiveness of the safety management process. Despite the importance of using effective hotspot identification (HSID) methods, only a few researchers have compared the performance of various methods. In this research, seven commonly applied HSID methods were compared against four robust and informative quantitative evaluation criteria. The following HSID methods were compared: crash frequency (CF), equivalent property damage only (EPDO) crash frequency, crash rate (CR), proportion method (P), empirical Bayes estimate of total-crash frequency (EB), empirical Bayes estimate of severe-crash frequency (EBs), and potential for improvement (PFI). The HSID methods were compared using the site consistency test, the method consistency test, the total rank differences test, and the total score test. These tests evaluate each HSID method's performance in a variety of areas, such as efficiency in identifying sites that show consistently poor safety performance, reliability in identifying the same hotspots in subsequent time periods, and ranking consistency. To evaluate the HSID methods, five years of crash data from the Italian motorway A16 were used. The quantitative evaluation tests showed that the EB method performs better than the other HSID methods. Test results highlight that the EB method is the most consistent and reliable method for identifying priority investigation locations. The EB expected frequency of total-crashes (EB) performed better than the EB expected frequency of severe-crashes (EBs), although the results differed only slightly when the number of identified hotspots increased. The CF method performed better than other HSID methods with more appealing theoretical arguments. In particular, the CF method performed better than the CR method. This result is quite alarming, since many agencies use the CR method. The PFI and EPDO methods were largely inconsistent. The proportion method performed worst in all of the tests. Overall, these results are consistent with the results of previous studies. The identification of engineering countermeasures that may reduce crashes was successful in all of the hotspots identified with the EB method; this finding shows that the identified hotspots can also be corrected. The advantages associated with the EB method were based on crash data from one Italian motorway, and the relative performances of HSID methods may change when using other crash data. However, the study results are very significant and are consistent with earlier findings. To further clarify the benefits of the EB method, this study should be replicated in other countries. Nevertheless, the study results, combined with previous research results, strongly suggest that the EB method should be the standard in the identification of hotspots.

Cold-Water Dousing with Ice Massage to Treat Exertional Heat Stroke: A Case Series

We sought to determine the rate of cooling via a novel water ice therapy (WIT) as an alternative to cold-water immersion for the acute treatment of exertional heat stroke (EHS). Observations were made at the 2004-2008 Marine Corps Marathons (mean +/- SD: 16.3 +/- 4.9 degrees C dry bulb, 32 +/- 6% RH). Nine (seven men, two women) EHS patients (33 +/- 6 yr of age; 268 +/- 54 min average race time for six who finished) were observed during on-site treatment. Patients were treated while lying supine on a porous stretcher resting on a tub filled with cold water (approximately 10-12 degrees C). Medical personnel monitored T(re), doused the patient with water and massaged major muscle groups with ice bags until T(re) decreased to 38.9 degrees C. Patients were not immersed in water. Serial T(re) and time were used to calculate cooling rates. Final T(re) (39.12 +/- 0.63 degrees C) was significantly lower than initial T(re) (41.43 +/- 0.71 degrees C, P < 0.05). Cooling rates were 0.13 +/- 0.04 degrees C min(-1). The decrease in T(re) for the initial 6 min of WIT (0.38 +/- 0.13 degrees C) was significantly less than for the subsequent 6-min time period (1.31 +/- 0.34 degrees C, P < 0.001). Cooling rates for these time periods were significantly different (0.06 +/- 0.02 degrees C x min(-1) and 0.22 +/- 0.06 degrees C x min(-1), respectively, P < 0.05). Initial T(re) was not correlated with overall cooling rate (r = 0.434, P = 0.244), or total cooling time required (17 +/- 4 min; r = 0.207, P = 0.593). Survival rate was 100%. WIT provided cooling rates that were 70% as effective as those published for cold-water immersion with 8 degrees C water (0.19 degrees C x min(-1)) and resulted in 100% patient survival.

Incorporating Laparoscopy in the Practice of a Gynecologic Oncology Service: Actual Impact Beyond Clinical Trials Data

Feasibility and safety of laparoscopic management of gynecologic cancers have been established by numerous clinical trials. However, the degree to which such results are achievable outside the context of formal research programs and the actual extent of laparoscopy uptake since its introduction are unclear. Purpose of this study was to examine the impact upon operative and cancer outcomes of the incorporation of laparoscopy into the surgical practice of our gynecologic oncology service. Data from 383 consecutive women undergoing surgery for the treatment of an apparently early-stage gynecologic cancer between 2000 and 2008 were analyzed. Integration of minimally access surgery for the treatment of invasive malignancies began with borderline ovarian tumors in 2001 and proceeded sequentially to include endometrial, ovarian, and cervical cancer patients. The annual proportion of laparoscopic cases has increased significantly over the study period from 7.7% in 2001 to 90.9% in 2008 (P < 0.0001 for trend). A temporal trend toward reduction in estimated blood loss was observed in both endometrial cancer and cervical cancer patients (P < 0.0001). There was a significant decrease in the percentage of patients requiring blood transfusions [18 (17.1%) during the period 2000-2002, 19 (13.6%) during 2003-2005, and 8 (5.8%) during 2006-2008; P = 0.005 for trend]. Length of hospital stay has decreased significantly over time for all disease sites (P < 0.0001 for endometrial and cervical cancer; P = 0.02 for ovarian cancer). No difference was found in median operative time, number of lymph nodes harvested, complication rates, 1- and 2-year disease-free survival, and overall survival when data of subsequent time periods were compared. Substantial utilization of laparoscopy in the existing practice of a gynecologic oncology service provided benefits to patients without detrimental effects on clinical outcomes. The relatively short follow-up time of laparoscopic cases disallows firm conclusions on long-term survival.

A time-periodic approach for fluid-structure interaction in distensible vessels

The analysis of periodic unsteady incompressible flow inside compliant vessels is of considerable interest for the simulation of blood flow in arteries. Weakly coupled fluid-structure interaction (FSI) models seem to be most suitable for this purpose. For weakly coupled solution methods, however, often convergence may not be achieved for compliant vessels with an axial length scale that is large compared to the characteristic radius. In this study, a time-periodic method for weakly coupled FSI models is presented. Approximate solutions of subsequent time-periods are obtained using the solution of the previous time-period as an initial solution. For the first period, not only suitable boundary conditions are derived from a 1-D wave propagation model, but also the initial axial pressure distribution. The time-periodic method was successfully applied to straight, curved and bifurcating geometries. The new approach proves to have a far better computational stability than weakly coupled methods based on timestep-wise coupling, especially in vessels with a length that is an order of magnitude larger than the radius.

Recent trends in acute lung injury mortality: 1996-2005.

Studies from single centers have suggested that mortality from acute lung injury (ALI) has declined over time. However, recent trends in ALI mortality from centers across the United States are unknown. We sought to determine whether recent advances in the treatment of ALI and related critical illnesses have resulted in decreased mortality from ALI. Retrospective cohort study of patients enrolled in the Acute Respiratory Distress Syndrome (ARDS) Network randomized controlled trials. Adult intensive care units participating in the ARDS Network trials. 2,451 mechanically ventilated patients with ALI enrolled in the ARDS Network randomized controlled trials between 1996 and 2005. Crude mortality was 35% in 1996-1997 and declined during each subsequent time period to a low of 26% in 2004-2005 (test for trend p < 0.0005). After adjusting for demographic and clinical covariates, including receipt of lower tidal volume ventilation and severity of illness, the temporal trend persisted (test for trend p = 0.002). When analyzed by individual causes of lung injury, there were not any statistically significant temporal trends in 60-day mortality for the most common causes of lung injury (pneumonia, sepsis, aspiration, and trauma). Over the past decade, there seems to be a clear temporal improvement in survival among patients with ALI treated at ARDS Network centers. Our findings strongly suggest that other advancements in critical care, aside from lower tidal volume ventilation, accounted for this improvement in mortality.

Effect of Acid Treatment on the High-Temperature Surface Oxidation Behavior of FeCrAlloy Foil Used for Methane Combustion Catalyst Support

The effect of acid treatment on the high-temperature oxidation behavior of Fe−Cr−Al alloy has been examined with oxidation tests and various characterization techniques. Acid treatment effectively improves the stability of the alloy in a high-temperature oxidation environment. After the treatment, the alloy oxidizes at a higher rate in the induction period and a lower rate in the subsequent time period. A passivative oxide layer was determined to be better formed during high-temperature oxidation on the surface of the acid-treated alloy, which suppressed further oxidation. It was observed that the oxidation rate of the alloy at high temperature can be described precisely by the Quadakkers equation.

Use of New Technology, But Not Study Participation Increases Adenoma Detection: A Comparative Study On 4700 Screening Colonoscopies (Berlin Colonoscopy Project 4, BECOP-4)

Background: It has never been examined whether use of new generation endoscopes with various technological improvements also improve colonoscopy outcome. Such an effect could be overrun by a general quality improvement effect caused by study participation per se. Methods: Adenoma detection rates (ADR; all adenomas/all patients) of 4747 persons undergoing screening colonoscopy in 5 private Berlin gastroenterology offices were analyzed for 3 subsequent similar time periods: Cases done under routine quality control documentation (group I; retrospective analysis; n=2091), and cases from two prospective studies: a general quality assessment study using the same standard colonoscopes as in group I (group II; n = 1400) and a subsequent study uniformly using high definition television (HDTV) imaging (group III; n=1256). Main outcome parameter was the difference in ADR between these three settings. Results: There was no difference between the groups in terms withdrawal time, which was only measured in studies II/III (8.0 vs. 8.2 min). ADR was significantly higher in the HDTV study (III: 0.33) than in the two periods before (I: 0.30; II: 0.27; p<0.01). Adenomas with high-grade dysplasia were also found more frequently in study III (1.3%) versus the other two periods (I: 0.7%; II: 0.6%), but this difference was statistically only significant for group II versus III. Conclusions: The uniform use of a new technology (HDTV) improved overall adenoma detection rates by 15%; risk lesions such as high grade dysplastic adenomas may be found more frequently. This effect was not due to study participation per se.

A Method for Standardizing Procedures in Rehabilitation: Use in the Extremity Constraint Induced Therapy Evaluation Multisite Randomized Controlled Trial

Morris DM, Taub E, Macrina DM, Cook EW, Geiger BF. A method for standardizing procedures in rehabilitation: use in the Extremity Constraint Induced Therapy Evaluation multisite randomized controlled trial. Objective An enduring problem in the field of rehabilitation has been the lack of standardization in the protocols of treatments and tests. To develop a process evaluation method to standardize the administration of rehabilitation procedures used in the Extremity Constraint Induced Therapy Evaluation (EXCITE) Trial, a randomized controlled trial of upper-extremity constraint-induced therapy implemented across 7 sites. Design Process evaluation. Setting Research laboratory. Participants Convenience sample or research personnel. Interventions Not applicable. Main Outcome Measures Checklist scoring sheets were developed to rate videotapes using systematic application of prescribed steps for each of 5 procedures across 3 time periods. Time periods were immediately after training, and 1 and 2 years later. A performance score of at least 90% was required before individual research personnel were allowed to participate in the trial. Results Overall performance scores ranged from 85.8% to 95% of performance items correctly executed. There was a significant improvement in standard performance of procedures between the first time period (immediately after training) and each of the subsequent time periods for all but 1 procedure. The scoring of standardized performance when carried out with routine participant testing and training did not differ significantly from scoring from videotaped sessions submitted for standardization rating for 2 of the procedures, suggesting adequate validity of scoring from videotape. Conclusions The present method was successful in assessing protocol fidelity for the EXCITE research personnel and represents 1 means of addressing the longstanding problem in rehabilitation of the lack of standardization in administering different treatments and tests.

The Effects of Non-Employment in Early Work-Life on Subsequent Employment Chances of Individuals in The Netherlands

In this article, the effects of non-employment in early work-life on subsequent employment chances of individuals in the Netherlands are examined. A main concern is whether the experience of non-employment in the beginning of the career (permanently) damages a worker’s later employment opportunities (that is, the likelihood of exit out of and re-entry into employment). The empirical analysis is based on five retrospective life-history surveys collected in the Netherlands in the period 1992–2003, with full information on employment histories of individuals. The analytic sample consists of 7,761 respondents, who left education since the 1950s. The results of the empirical analysis first of all show that the duration of non-employment in the first 3 years after leaving education (and not the number of non-employment spells in that period) increases the likelihood of exiting employment in the subsequent time period (up until 15 years after leaving education). This finding holds for both men and women. Second, a negative duration effect of non-employment on the likelihood of re-entering employment after a job loss is found, but for men only. These results imply that non-employment in early work-life indeed has a scarring effect on subsequent employment chances of individuals in the Dutch labour market.

Sources of water vapour contributing to the Elbe flood in August 2002—A tagging study in a mesoscale model

AbstractIn this study we investigate the contribution of various moisture sources to the Elbe flood that occurred in Central Europe during August 2002. An 8‐day simulation with the mesoscale numerical weather prediction model CHRM, including newly implemented water vapour tracers, has been performed. According to the simulation, rather than drawing moisture from one single dominant source region, water vapour from widely separated moisture sources contributed to the extreme precipitation in the most affected area, notably at distinct, subsequent periods of time, and each in significant amounts. These moisture sources include the Atlantic and Mediterranean ocean areas inside the model domain, evapotranspiration from land areas, and long‐range advection from subtropical areas outside the model domain.The results highlight the importance of the concurrent upper‐level circulation and the mesoscale flow structures associated with the cyclone for producing extreme precipitation in parts of Germany, Austria, and the Czech Republic during that period. Furthermore, the numerical and technical problems of implementing water vapour tracers into a limited‐area model are discussed, including conservative tracer advection, initialization, boundary treatment, and the handling of precipitation parametrizations. An evaluation of the consistency of the method in terms of water vapour, cloud water, and precipitation is provided, with generally satisfying results. The model with its detailed water vapour tracer implementation can now be used for further case‐studies and climatological simulations, and serve as a reference for evaluating the performance of other moisture tracking methods, such as those based on backward trajectories. Copyright © 2009 Royal Meteorological Society

迅速測図をはじめとする各種地図のＧＩＳ解析による茨城県南部における農村土地利用の時系列変化の研究

In order to carry out a time-series analysis of rural land use change covering 120 years in a research area in southern Ibaraki Prefecture, this study carried out a GIS overlay analysis of maps representing the 1880s, 1910s, 1950s, 1980s, and 2000s. The earliest were the Rapid Survey Maps and the latest were the Ministry of Environment vegetation maps. Land use changes that occurred between time periods were classified into no change, change among rural land uses (such as between woodland and fields), and change into urban land uses. From the 1880s to the 1950s, most land use changes occurred between rural land uses. From the 1950s, land use change into urban uses became prominent. The rural land uses differed in the temporal trends of increase or decrease, and in the time periods when they reached the maximum proportion in the map area. Large grasslands appear prominently in the study area in the 1880s, but no longer appear in subsequent time periods. Woodlands and rice paddy reach the highest proportion of the study area in the 1910s, fields in the 1950s, and residential areas in the 2000s.

Bias adjustment techniques for improving ozone air quality forecasts

In this study, we apply two bias adjustment techniques to help improve forecast accuracy by postprocessing air quality forecast model outputs. These techniques are applied to modeled ozone (O3) forecasts over the continental United States during the summer of 2005. The first technique, referred to as the hybrid forecast (HF), combines the most recent observed ozone with model‐predicted ozone tendency for the subsequent forecast time period. The second technique applied here is the Kalman filter (KF), which is a recursive, linear, and adaptive method that takes into account the temporal variation of forecast errors at a specific location. Two modifications to the Kalman filter are investigated. A key parameter in the KF approach is the error ratio, which determines the relative weighting of observed and forecast ozone values. This parameter is optimized to improve the prediction of ozone based on time series data at individual monitoring sites in the Aerometric Information Retrieval Now network. The optimal error ratios inherent in the KF algorithm implementation are found to vary across space; however, comparisons of the resultant KF‐adjusted forecasts using a single fixed value of this parameter with those using the optimal values determined for each individual site reveal similar results, suggesting that the uncertainty in the estimation of this parameter does not have a significant impact on the final bias‐adjusted predictions. The KF postprocessing is also combined with the Kolmogorov‐Zurbenko filter, which extracts the intraday variability in the observed ozone time series; the results indicate a significant improvement in the ozone forecasts at locations in the Pacific coast region, but not as much at locations across the rest of the continental U.S. domain. Both HF and KF bias adjustment techniques help significantly reduce the systematic errors in ozone forecasts. For most of the global performance metrics examined, the KF approach performed better than the HF method. For the given model applications, both methods are effective in reducing biases at low ozone mixing ratio levels, but not as well at the high mixing ratio levels. This is due in part to the fact that high ambient ozone levels occur much less frequently than low to moderate levels for which the current model exhibits a systematic high bias. Additionally, the 12 km model grid structure is often unable to adequately capture the magnitude of peak O3 levels. Thus, these extreme events at discrete monitor locations are more difficult to predict.

Determinants of open source software project success: A longitudinal study

In this paper, we investigate open source software (OSS) success using longitudinal data on OSS projects. We find that restrictive OSS licenses have an adverse impact on OSS success. On further analysis, restrictive OSS license is found to be negatively associated with developer interest, but is positively associated with the interest of non-developer users and project administrators. We also show that developer and non-developer interest in the OSS project and the project activity levels in any time period significantly affect the project success measures in subsequent time period. The implications of our findings for OSS research and practice are discussed.

Systemic Endocrine Instigation of Indolent Tumor Growth Requires Osteopontin

The effects of primary tumors on the host systemic environment and resulting contributions of the host to tumor growth are poorly understood. Here, we find that human breast carcinomas instigate the growth of otherwise-indolent tumor cells, micrometastases, and human tumor surgical specimens located at distant anatomical sites. This systemic instigation is accompanied by incorporation of bone-marrow cells (BMCs) into the stroma of the distant, once-indolent tumors. We find that BMCs of hosts bearing instigating tumors are functionally activated prior to their mobilization; hence, when coinjected with indolent cells, these activated BMCs mimic the systemic effects imparted by instigating tumors. Secretion of osteopontin by instigating tumors is necessary for BMC activation and the subsequent outgrowth of the distant otherwise-indolent tumors. These results reveal that outgrowth of indolent tumors can be governed on a systemic level by endocrine factors released by certain instigating tumors, and hold important experimental and therapeutic implications.

Time-lapse seismic modeling assisted by numerical reservoir simulation of water and gas flooding scenarios in oil reservoirs

In this project, we link fluid flow simulation results to time-lapse seismic through rock physics and modeling. Our goal is to examine the main effects of permeability barriers on seismic response using fluid flow simulations to generate pressure and saturation fields. To explore this problem, we have carried out water and gas injection numerical experiments in a simple reservoir model which has vertical and horizontal variations of porosity as well as permeability barriers. In each experiment, we change the barrier permeability values. By using fluid substitution theory, Gassmann and patchy models, and Batzle and Wang's empirical relationship we model the main seismic parameters, such as acoustic impedance and compressional velocity. After that, we generate synthetics seismograms and some contrast sections to compare the seismic images prior and after fluid injection events in subsequent time periods to analyze possible differences in the seismic parameters due to changes in barriers properties. The results show that barriers can increase fluid pore pressure changing the bulk modulus in the regions with barriers. The results also show that water flow does not have significant impact on seismic response when the barrier is present. On the other hand, gas flow and the degree of impermeability of the barrier can help us to understand how the barriers act on the seismic response and thus to reduce uncertainty. Finally, this paper presents a methodology to examine barriers effects on seismic response.

Application of time-lapse ERT imaging to watershed characterization

Time-lapse electrical resistivity tomography (ERT) has many practical applications to the study of subsurface properties and processes. When inverting time-lapse ERT data, it is useful to proceed beyond straightforward inversion of data differences and take advantage of the time-lapse nature of the data. We assess various approaches for inverting and interpreting time-lapse ERT data and determine that two approaches work well. The first approach is model subtraction after separate inversion of the data from two time periods, and the second approach is to use the inverted model from a base data set as the reference model or prior information for subsequent time periods. We prefer this second approach. Data inversion methodology should be consideredwhen designing data acquisition; i.e., to utilize the second approach, it is important to collect one or more data sets for which the bulk of the subsurface is in a background or relatively unperturbed state. A third and commonly used approach to time-lapse inversion, inverting the difference between two data sets, localizes the regions of the model in which change has occurred; however, varying noise levels between the two data sets can be problematic. To further assess the various time-lapse inversion approaches, we acquired field data from a catchment within the Dry Creek Experimental Watershed near Boise, Idaho, U.S.A. We combined the complimentary information from individual static ERT inversions, time-lapse ERT images, and available hydrologic data in a robust interpretation scheme to aid in quantifying seasonal variations in subsurface moisture content.

Hope and Spiritual Well-Being in Adolescents With Cancer

This study examines the relationships of hope and spiritual well-being (SWB)--and its dimensions, religious well-being (RWB) and existential well-being (EWB)--to time since diagnosis among adolescents with cancer. A descriptive cross-sectional design was used. The sample of 78 adolescents diagnosed with cancer was recruited from two pediatric oncology clinics. Adolescents in the first two time periods reported significantly higher levels of SWB, RWB, and EWB than those in subsequent time periods. Hope did not significantly vary over time. Hence, time since diagnosis may influence adolescents' levels of SWB and its dimensions during the cancer experience. Adolescents' use of SWB, RWB, and EWB as coping resources should be examined in longitudinal studies from diagnosis through survivorship.

Erratum: NICU lactation consultant increases percentage of outborn versus inborn babies receiving human milk

Correction to: Journal of Perinatology (2008) 28, 136–140. doi:10.1038/sj.jp.7211888. Following the publication of the above paper, the author identified the following error in the text: In the figure 1 caption, it should read ‘Time 3:1 July 2003 to 30 September (subsequent 3-month time period afterIBCLC hire)’ instead of ‘Time 3:1 January 2003 to 30 September (subsequent 3-month time period after IBCLC hire).

Infant Mortality in the Lower Mississippi Delta: Geography, Poverty and Race

The objectives of this study were to explore regional, economic and racial disparities in infant mortality rates between geographic sub-regions within the eight states containing the Delta and to test hypotheses that regional disparities would decrease over time while county poverty level and racial composition would remain significant predictors of infant mortality rates. The study used secondary data analysis of county level rates, including descriptive statistics, hierarchical multiple regression with interaction effects and linear multiple regression. Models testing the impact of sub-regional geographic differences, percent of poverty, percent of black population and interaction effects were conducted at three time periods, the late 1970s, late 1980s and late 1990s. In the first time period, regional differences, percent of poverty, percent of black population and the interaction of region and poverty were all predictive of infant mortality (R(2) = 0.31, P < 0.0001). In the subsequent time periods, only percent of poverty and percent of black population were significant predictors (R(2) = 0.20, P < 0.0001 and R(2) = 0.26, P < 0.0001). During the late 1970s and early 1980s, region, poverty and racial composition of counties all played an important part in predicting life chances for infants born in these eight states. Furthermore, Central Delta infants in counties with poverty levels of 30% or greater were significantly more likely to die than infants in other areas with the same rates of poverty, even after controlling for racial composition. The impact of regional differences was no longer significant at the ends of the subsequent two decades. Both medical and policy changes during these decades may have contributed to the decreased impact of region. However, both poverty and racial composition continue as important factors, accounting for more variance in the late 1990s than a decade before.