The role of fertility and population in economic growth: empirical research from aggregate cross-national data.
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Demography↗
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Results for “Data Aggregation”
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Pathways of behavioural and emotional symptoms in kindergarten children: what is the role of pro-social behaviour?
The study investigated the predictive value of pro-social behaviour for developmental pathways of behavioural and emotional problems at kindergarten age. One hundred and sixty children participated in the study at the ages of 5 and 6. Teachers and parents completed the Strengths and Difficulties Questionnaire; children completed the Berkeley Puppet Interview at both assessment points. Single-informant data were aggregated to enhance the reliability and validity of data. Gender and parental educational status were controlled. Symptoms (conduct problems, hyperactivity and emotional symptoms) and pro-social behaviour were moderately stable over time. Compared to girls, boys showed higher levels and increases of conduct problems and hyperactivity and lower levels of pro-social behaviour. Lower parental educational level was associated with higher levels and increases in hyperactivity. Although pro-social behaviour was cross-sectionally associated with behavioural and emotional symptoms, pro-social behaviour did not predict changes in conduct problems or hyperactivity over time. However, children with above average emotional symptoms and above average pro-social behaviour at Age_5 showed the highest level of emotional symptoms at Age_6. The results indicate that low levels of pro-social behaviour are associated with children's externalising behaviour problems, but that for children with high levels of emotional symptoms, higher levels of pro-social behaviour should also be considered as a risk factor. In sum, our results suggest mainly homotypic pathways of internalising and externalising symptoms across kindergarten age, but indicate that the assessment of pro-social behaviour yields additional information regarding the developmental pathways of emotional symptoms.
Adult↗
Interrelation of platelet aggregation, release reaction and thromboxane A2 production.
Aggregation of platelets, stimulated by different agonists, was inhibited by omitting sample stirring or by preincubation of platelets with a monoclonal antibody against glycoproteins IIb-IIIa or with a pentapeptide containing the sequence Arg-Gly-Asp-Ser. In platelets stimulated by collagen, ADP and epinephrine, the inhibition of aggregation paralleled a reduction of both release reaction and thromboxane A2 formation. When thrombin was the stimulus, ATP release and thromboxane A2 production were unaffected (or only slightly modified) by the inhibition of platelet aggregation. These data add further evidence to the hypothesis that aggregation supports the activation of platelets stimulated by weak agonists.
Adenosine Diphosphate↗
Hard and soft data on anti-aggregating agents.
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Clinical Trials as Topic↗
Dynamic scaling in colloidal aggregation: Comparison of experimental data with results of a stochastic simulation.
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Journal Article↗
The thrombin receptor extracellular domain contains sites crucial for peptide ligand-induced activation.
A thrombin receptor (TR) demonstrating a unique activation mechanism has recently been isolated from a megakaryocytic (Dami) cell line. To further study determinants of peptide ligand-mediated activation phenomenon, we have isolated, cloned, and stably expressed the identical receptor from a human umbilical vein endothelial cell (HUVEC) library. Chinese hamster ovary (CHO) cells expressing a functional TR (CHO-TR), platelets, and HUVECs were then used to specifically characterize alpha-thrombin- and peptide ligand-induced activation responses using two different antibodies: anti-TR34-52 directed against a 20-amino acid peptide spanning the thrombin cleavage site, and anti-TR1-160 generated against the NH2-terminal 160 amino acids of the TR expressed as a chimeric protein in Escherichia coli. Activation-dependent responses to both alpha-thrombin (10 nM) and peptide ligand (20 microM) were studied using fura 2-loaded cells and microspectrofluorimetry. Whereas preincubation of CHO-TR with anti-TR34-52 abolished only alpha-thrombin-induced [Ca2+]i transients, preincubation with anti-TR1-160 abrogated both alpha-thrombin- and peptide ligand-induced responses. This latter inhibitory effect was dose dependent and similar for both agonists, with an EC50 of approximately 90 micrograms/ml. Anti-TR1-160 similarly abolished peptide ligand-induced [Ca2+]i transients in platelets and HUVECs, whereas qualitatively different responses characterized by delayed but sustained elevations in [Ca2+]i transients were evident using alpha-thrombin. Platelet aggregation to low concentrations of both ligands was nearly abolished by anti-TR1-160, although some shape change remained; anti-TR34-52 only inhibited alpha-thrombin-induced aggregation. These data establish that a critical recognition sequence for peptide ligand-mediated receptor activation is contained on the NH2-terminal portion of the receptor, upstream from the first transmembrane domain. Furthermore, alpha-thrombin-induced activation of HUVECs and platelets may be partially mediated by an alternative mechanism(s) or receptor(s).
Animals↗
National marriage data: a re-aggregation of John Rickman's marriage returns.
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Demography↗
Drug Treatment as a Crime Fighting Tool.
BACKGROUND: The primary approach to reducing crime in the US has been through the criminal justice system. However, drug treatment may be an effective tool in reducing crime. In order to make better use of treatment as an alternative approach, one needs to know if reducing drug use through treatment results in decreased crime. AIMS OF THE STUDY: The objective of this paper is to model and empirically investigate the extent to which a change in drug use that results from treatment reduces crime and whether a change in drug use is causally related to change in crime. We focus on crime-for-profit. METHODS: We use a multi-site dataset of 3,502 inner-city drug users entering treatment. We analyze the change in drug use and crime pre and post treatment. We take first differences to address the omitted variable problem. RESULTS: We find that treatment reduces drug use and that, in turn, reduced drug use has a significant impact on crime. For our study population, reduced drug use seems to be causally related to reduced crime. This finding is robust to specification and subsamples. We estimate that reduced drug use due to treatment is associated with 54% fewer days of crime for profit, ceteris paribus. DISCUSSION: We use a longitudinal data set and a novel approach to analyze the relationship between crime and drugs. We analyze a low-income, inner-city, drug-addicted sample. We use self-reported crime. For our purposes, the use of individual data is an improvement over the use of aggregate level data that has been used in much of the related literature. Limitations of our paper include that we do not have a random sample and that our measure is self-reported in the previous 30 days. IMPLICATIONS FOR HEALTH POLICIES: Our findings suggest that drug treatment may be an effective crime-fighting tool. Treatment reduces not only the crime of drug possession, but also crime-for-profit. Current public policy emphasizes use of the criminal justice system, incarceration in particular, as a mechanism to combat crime. Given the huge and growing expense of the criminal justice system, drug treatment might be cost-effective relative to incarceration. California s so called Proposition 36 is based on this yet to be proven premise. Although additional research is required, our findings may help inform the debate on treatment versus criminal justice. We have provided empirically-based findings that reduced drug use due to treatment can result in important reductions in crime. Our findings can serve as a building block for policy development.
Journal Article↗
Morbidity surveillance after Hurricane Katrina--Arkansas, Louisiana, Mississippi, and Texas, September 2005.
Hurricane Katrina made landfall on the U.S. Gulf Coast on August 29, 2005. Thousands of Gulf Coast residents evacuated and dispersed across the country, moving into hotels, private homes, and evacuation centers (ECs) in 30 states and the District of Columbia (DC). One goal of public health responders was to identify and prevent hurricane-related morbidity and mortality among affected populations, especially among those with limited access to health care and those who were living in crowded conditions. This report summarizes the challenges of conducting national surveillance after Hurricane Katrina, focusing on the role of CDC in coordinating surveillance and consolidating and interpreting morbidity data from jurisdictions that used diverse surveillance approaches. Aggregate morbidity data that were reported through Arkansas, Louisiana, Mississippi, and Texas to CDC during September 1-22, 2005 (before the Gulf Coast landfall of Hurricane Rita on September 24) are presented from ECs and health-care facilities (HCFs) that served affected populations in these states. Chronic diseases and injuries were the most common conditions reported by ECs and HCFs, respectively. To better prepare for future large-scale disasters with widespread impact, public health agencies and other partners are actively working to establish standardized guidelines and tools for morbidity surveillance. These guidelines will facilitate the interpretation and exchange of health information among multiple jurisdictions and public and private agencies during a disaster response to identify outbreaks and monitor health concerns.
Arkansas↗
Quality assurance measurements in departments of pathology and laboratory medicine.
Previously, characteristics of the quality assurance program in each department of pathology and laboratory medicine were the uniqueness of the monitors selected, the thresholds set for activity, and definitions of good performance. In 1989, members of the College of American Pathologists developed and implemented the first nationwide quality assurance program for pathology and laboratory medicine. This program, Q-Probes, has been expanded for 1990; after completion of planning under way for 1991, indicators will be in place for all steps in the total testing process. More than 1100 institutions had subscribed by the first quarter of 1990. Input forms for measurements of clinical indicators of quality are distributed to participants and, after completion, submitted to a central computer facility where keypunching and data manipulations occur. The interpretation of results is enhanced by peer comparisons of the participant data collected. In many circumstances studied, a large proportion of the data are aggregated at extreme ends of the distribution. Because data distributions are nongaussian for the indicators studied, it is recommended that peer comparisons use the 10% to 90% range and that the central tendency be described as the median. Despite large databases for some indicators that exceed by more than 10- to 100-fold those previously reported, extensive categorization may preclude percentile ranking of participants. Critiques are distributed describing practices and suggestions for improvement. Steady improvement of each participant and of nationwide practice patterns are documented by remeasurements.
Data Collection↗
[Erythrocyte aggregation and retinal vein occlusion. Preliminary data for a randomized study on the efficacy of anti-erythrocyte aggregation (troxerutin) in retinal vein occlusion].
Erythrocyte aggregation (EAg) is one of the principal determinants of blood viscosity at low shearing rates (slow flow). The retinal venous circulation, characterised by a slow circulatory rate and a high resistance to flow, creates a favourable environment for the formation of erythrocyte aggregates. EAg and other laboratory parameters (haematocrit, fibrinogen, plasma proteins, clotting) were measured in 64 patients presenting with retinal vein occlusion (RVO) and 64 controls matched for age, sex, risk factors (HT, diabetes, smoking) and concomitant vascular disease. Statistical analysis of the results demonstrated a significant difference between the RVO group and the control group for fibrinogen (p = 0.03) and erythrocyte aggregation (p = 0.00003 for the aggregation index at 10 sec and p = 0.0002 for the threshold of partial dissociation). The rise in the fibrinogen level alone cannot explain the increased erythrocyte aggregation. These results demonstrate that the increased EAg largely explains the hyperviscosity reported by other authors and suggest that it plays an important role in the pathogenesis of RVO.
Adult↗
Roles of extracellular matrix components in differentiating teratocarcinoma cells.
F9 embryonal carcinoma cells treated with 5 X 10(-8) M retinoic acid and cultured in suspension for 8 days form aggregates consisting of an outer epithelial layer of alpha-fetoprotein-producing visceral endoderm cells. We have previously shown (Grover, A., Oshima, R. G., and Adamson, E. D. (1983) J. Cell Biol. 96, 1690-1696) that the differentiation of F9 cells to visceral endoderm is accompanied by the activation of several genes, and increased laminin synthesis is one of the earliest events. Here we analyze in detail the syntheses and secretion of fibronectin, type IV collagen, and laminin during the 8-day process. Employing immunoprecipitation and enzyme-linked immunosorbent assay, we show that the levels of all three components change with different patterns. Unstimulated F9 cells synthesize and secrete relatively high levels of fibronectin and low levels of type IV collagen. Fibronectin synthesis and secretion decreases to 10% of its original level whereas type IV collagen synthesis rises approximately 3-fold during the differentiation process. Laminin synthesis also rises at least 2-fold, and the proportions of its subunits change as the syntheses of B1 and A accelerate starting on day 2. However, unlike fibronectin and type IV collagen, laminin is largely accumulated in the aggregates. The data suggest that fibronectin has a role in aggregation whereas laminin is important in the differentiation process.
Animals↗
Co-clustering of beta 1 integrins, cytoskeletal proteins, and tyrosine-phosphorylated substrates during integrin-mediated leukocyte aggregation.
The involvement of the VLA-4 integrin in an alternative leukocyte homotypic adhesion mechanism that is LFA-1/ICAM-1 independent, has been previously reported. We describe here the localization of beta 1 and alpha 4 integrin subunits at sites of cell-cell contact, on both beta 1- and alpha 4-induced aggregates of B lymphoblastoid Ramos cells. Moreover, the distribution of different VLA-alpha subunits was also examined on beta 1-induced cell aggregates of alpha 2- and alpha 4-transfected K-562 cells. Both alpha 2 and alpha 4 integrin subunits were mainly localized at sites of intercellular boundaries, suggesting a possible role for these integrins in leukocyte intercellular adhesion. The fibronectin receptor alpha 5 subunit was either diffuse throughout the plasma membrane, or displayed some accumulation at sites of cell-cell contact. Even though homotypic aggregation of U-937 cells was induced with the anti-alpha 5 P1D6 mAb, the alpha 5 subunit showed only partial redistribution to regions of cell-cell contact, compared with the complete redistribution of the alpha 4 subunit in the alpha 4-induced aggregates. The reorganization of the actin-cytoskeleton was observed at sites of intercellular boundaries in both the anti-beta 1- and anti-alpha 4-induced cell aggregates. Hence, F-actin and the cytoskeletal protein talin co-localized with beta 1 and alpha 4 integrin clusters at sites of cell-cell contact. Signal transduction during VLA-mediated homotypic cell adhesion has also been investigated. We found co-localization of beta 1 and alpha 4 subunits with tyrosine-phosphorylated proteins at cell-cell contact regions during cell aggregation. These data indicate that VLA integrin-mediated leukocyte aggregation results in clustering of beta 1-integrins at sites of cell-cell contact, together with co-localization of cytoskeletal proteins. These results also suggest that protein tyrosine phosphorylation is an important signal transduction mechanism when VLA integrins participate in intercellular contacts.
Actins↗
The production of dialysis by for-profit versus not-for-profit freestanding renal dialysis facilities.
OBJECTIVE: A study was conducted to determine whether for-profit and not-for-profit freestanding renal dialysis facilities differ with respect to efficiency in the production of dialysis treatments. DATA SOURCES/STUDY SETTING: National data on 1,224 Medicare-certified freestanding dialysis facilities were obtained from the Health Care Financing Administration's (HCFA) 1990 Independent Renal Dialysis Facility Cost Report. Data on Medicare patients receiving care at these facilities during 1990 were obtained from HCFA's End Stage Renal Disease (ESRD) Program Management and Medical Information System (PMMIS). STUDY DESIGN: Ordinary least squares regression (OLS) was used to estimate the association between monthly output of dialysis treatments in 1990 and (a) facility capital and labor inputs, (b) facility ownership characteristics, and (c) case-mix characteristics. DATA COLLECTION/EXTRACTION METHODS: Facility and patient level data were extracted from the Facility Cost Report and the PMMIS databases, respectively. Patient level data were aggregated by facility and merged with facility level data. PRINCIPAL FINDINGS: For-profit sole proprietorships, for-profit partnerships and for-profit corporations each produced significantly more dialysis treatments per month than not-for-profits, adjusting for quantities of resource inputs and case-mix characteristics. CONCLUSION: For-profit facilities appear to be more efficient producers of dialysis treatments than not-for-profits. Further study should address whether other factors such as differences in severity of disease or in quality of care are responsible for these observations.
Ambulatory Care Facilities↗
Does hospital procedure-specific volume affect treatment costs? A national study of knee replacement surgery.
OBJECTIVE: The long-run cost savings potential of private sector reform efforts, such as selective contracts with providers, depends in part on the relationship between procedure-specific volume and average hospital resources that are consumed in treating patients associated with that specific procedure. Study examines a model that estimates the relationship between hospital procedure-specific volume and average hospital treatment costs, using an elective surgical procedure as an example. DATA SOURCES: Medicare Provider Analysis and Review (MedPAR) files for 1989 for hospitalizations in which a Medicare beneficiary received a knee replacement (KR) surgery during 1989. Hospital information was obtained from the American Hospital Association's 1989 Annual Survey. All patient-level data were aggregated to the hospital level to create a data file, with the hospital as the unit of observation. STUDY DESIGN: This study used administrative claims data and regression analysis to estimate the effect of hospital procedure-specific volume on average hospital treatment costs of patients receiving KR surgery. We also examined the stability of the volume-cost relationship across hospitals of different sizes. PRINCIPAL FINDING: The average treatment costs associated with KR surgery are inversely related to a hospital's KR volume in the regression equation estimated using all hospitals performing KR surgery. The inverse relationship between cost and volume is found to be robust for different-size hospitals. CONCLUSIONS: The potential cost savings associated with performing KR surgery at incrementally higher hospital volume level can amount to as much as 10 percent of the hospital's average treatment cost. However, the incremental cost savings associated with increased patient volume depends on the hospital's current volume level and its size.
Aged↗
A quantitative evaluation of sex differences in implicit personality theories.
An investigation is conducted into whether male and female perceivers hold substantially different implicit theories of personality. 24 male and 24 female subjects were asked to sort a set of 36 trait names into groups of similar traits. On the basis of these data, proximities between trait names and proximities between groupings (or partitions) were computed and subjected to a differential statistical analysis. Neither a global test for sex-specific groupings of trait names nor tests at the level of perceived pairwise trait relationships yielded significant differences. It is concluded that aggregation of sorting data over both male and female perceivers is warranted without too big a loss of information. On the methodological side, this paper demonstrates the feasibility of a quantitative approach to handling the problem of data aggregation in the context of studies using the sorting method as a data-gathering technique.
Adult↗
From GCM grid cell to agricultural plot: scale issues affecting modelling of climate impact.
General circulation models (GCM) are increasingly capable of making relevant predictions of seasonal and long-term climate variability, thus improving prospects of predicting impact on crop yields. This is particularly important for semi-arid West Africa where climate variability and drought threaten food security. Translating GCM outputs into attainable crop yields is difficult because GCM grid boxes are of larger scale than the processes governing yield, involving partitioning of rain among runoff, evaporation, transpiration, drainage and storage at plot scale. This study analyses the bias introduced to crop simulation when climatic data is aggregated spatially or in time, resulting in loss of relevant variation. A detailed case study was conducted using historical weather data for Senegal, applied to the crop model SARRA-H (version for millet). The study was then extended to a 10 degrees N-17 degrees N climatic gradient and a 31 year climate sequence to evaluate yield sensitivity to the variability of solar radiation and rainfall. Finally, a down-scaling model called LGO (Lebel-Guillot-Onibon), generating local rain patterns from grid cell means, was used to restore the variability lost by aggregation. Results indicate that forcing the crop model with spatially aggregated rainfall causes yield overestimations of 10-50% in dry latitudes, but nearly none in humid zones, due to a biased fraction of rainfall available for crop transpiration. Aggregation of solar radiation data caused significant bias in wetter zones where radiation was limiting yield. Where climatic gradients are steep, these two situations can occur within the same GCM grid cell. Disaggregation of grid cell means into a pattern of virtual synoptic stations having high-resolution rainfall distribution removed much of the bias caused by aggregation and gave realistic simulations of yield. It is concluded that coupling of GCM outputs with plot level crop models can cause large systematic errors due to scale incompatibility. These errors can be avoided by transforming GCM outputs, especially rainfall, to simulate the variability found at plot level.
Africa, Western↗
A suitable method for identifying cell aggregates in laser scanning cytometry listmode data for analyzing disaggregated cell suspensions obtained from human cancers.
BACKGROUND: The presence of cell aggregates in cell suspensions obtained from human solid tumors can interfere with the measurement of cell DNA content of cell singlets, and can confound multiparameter analysis of other measurements on the same cells. Flow cytometric corrections for cell aggregates based on signal pulse shape have not proven to be reliable. Mathematical models have been developed to correct for cell aggregates in binned DNA histogram data, but they are not suitable for the correction of correlated non-DNA measurements obtained on the same cells. METHODS: A total of 21 samples representing a variety of normal and malignant human cell types, including normal lymphocytes, normal sputum, human breast cancer cell lines, and mechanically disaggregated cell suspensions from primary breast cancers and nonsmall cell lung cancers, were studied by laser scanning cytometry (LSC) using the CompuCyte laser scanning cytometer (Cambridge, MA). Nuclear area, nuclear perimeter, and an LSC-based cell texture parameter were measured on approximately 400 cells in each sample, using an air-cooled, violet laser emitting at a wavelength of 405 nm for DAPI excitation, and each cell was classified as a singlet or aggregate by its appearance under direct observation. A "saddle function" provided by CompuCyte was used, together with an algorithm based on the measurements of nuclear area, perimeter, and cell texture (the APT algorithm), to identify cell aggregates and exclude them from the listmode data file. RESULTS: Proportions of cell aggregates in the uncorrected samples ranging from 6 to 56% (mean, 20%) were reduced to proportions ranging from 0 to 7% (mean, 2.4%) after correction. The discriminant function was "tuned" to maintain both average cell singlet purity and average cell singlet yield at >70% over a broad range of cell DNA contents. CONCLUSIONS: A combined approach to cell aggregate detection, which utilizes both the saddle function and the APT algorithm, produces list mode data files that exclude >80% of cell aggregates from samples of disaggregated cell suspensions of human tumors and other sources of clinical material. Such data files are suitable for multiparameter analysis.
Algorithms↗