Search

This paper examines the mechanical response of precast panel pavement repair joints under static aircraft loadings using the finite-element method. Three-dimensional finite-element models were developed using the Abaqus software code, and their results were compared to and validated against results of full-scale field tests and theoretical calculations. Unlike previous pavement repair modelling efforts for precast panels and dowel retrofitting studies, all parts of the repair joint were modelled, including the dowels, dowel slot material, parent concrete, precast panel and pavement sublayers. Results show that high stress concentrations occur in the dowel slot material and that the current panel design is likely to be improved by modifying the dowel diameter.

S-phase kinase-associated protein 2 (SKP2) is an important cell cycle regulator, targeting the cyclin-dependent kinase (CDK) inhibitor p27 for degradation, and is frequently overexpressed in breast cancer. p27 regulates G1 /S transition by abrogating the activity of cyclin/CDK complexes. p27 can undergo phosphorylation at serine 10 (pSer10p27). This phosphorylation event is associated with increased cell proliferation and poor prognosis in patients with glioma. The relationship between SKP2 and pSer10p27 in breast cancer has not been previously investigated. Immunohistochemistry (IHC) of SKP2, p27, pSer10p27, and other genes involved in this pathway, was analyzed in 188 breast tumors and 50 benign reduction mammoplasty samples. IHC showed SKP2 to be more highly expressed in estrogen receptor α (ERα)-negative breast cancers and demonstrated that triple-negative tumors were more likely to have high expression of SKP2 than were non-triple negative, ERα-negative tumors. A significant positive relationship was discovered for SKP2 and pSer10p27. High levels of SKP2 and pSer10p27 were observed significantly more often in ERα-negative and triple-negative than in ERα-positive breast cancers. Use of the triple-negative TMX2-28 breast cancer cell line to address the role of SKP2 in cell cycle progression confirmed that SKP2 contributes to a more rapid cell cycle progression and may regulates pSer10p27 levels. Together, the results indicate that presence of high SKP2 plus high pSer10p27 levels in triple-negative breast cancers is associated with aggressive growth, and highlight the validity of using SKP2 inhibitors as a therapeutic approach for treating this subset of breast cancers.

Matting systems are used for temporary applications on soft soils to reduce ground pressure exerted by aircraft, heavy equipment, vehicles, and construction material. They have been used for military airfields, construction platforms, and similar applications. Previous evaluation studies of matting systems have typically consisted of full-scale testing, with only a limited amount of numerical modeling found in the literature. This paper presents results of full-scale accelerated testing of 21 test sections encompassing five matting systems, five soil-support conditions, and two aircraft loadings. One of the soil-support conditions was instrumented and tested in conjunction with three matting systems and one aircraft loading. Three-dimensional finite-element modeling was performed on the instrumented sections using the measured test data for calibration. Good matches of measured soil stresses were obtained with the model for two of the mats, whereas the model underpredicted stresses in the third mat. Modeling of the type performed in this paper was capable of correctly ranking the performance of the matting systems modeled relative to the full-scale test results.

To evaluate how the calculation of a crystal energy landscape can be used in the solid-form screening of pharmaceuticals, a Knowledge Transfer Secondment between GlaxoSmithKline (GSK) and University College London was established to carry out computational crystal structure prediction (CSP) and further guided experimentation on a molecule from GSK’s compound collection. The molecule chosen was 6-[(5-chloro-2-([(4-chloro-2-fluorophenyl)methyl]oxy)phenyl)methyl]-2-pyridinecarboxylic acid (GSK269984B) since the preliminary thermodynamic form screening had only identified one anhydrate, Form I. The calculations confirmed that Form I is the most thermodynamically stable form. The thermodynamically competitive computed structures all had very different conformations of GSK269984B, and further experiments were designed to attempt to generate these conformations in solution and hence the crystalline solid. The experimental screening generated four novel solvates which all eventually transformed to Form I, two of ...

Accurately identifying women at increased risk of developing breast cancer will provide greater opportunity for early detection and prevention. DNA promoter methylation is a promising biomarker for assessing breast cancer risk. Breast milk contains large numbers of exfoliated epithelial cells that are ideal for methylation analyses. Exfoliated epithelial cells were isolated from the milk obtained from each breast of 134 women with a history of a non-proliferative benign breast biopsy (Biopsy Group). Promoter methylation of three tumor suppressor genes, RASSF1, SFRP1 and GSTP1, was assessed by pyrosequencing of bisulfite-modified DNA. Methylation scores from the milk of the 134 women in the Biopsy Group were compared to scores from 102 women for whom a breast biopsy was not a recruitment requirement (Reference Group). Mean methylation scores for RASSF1 and GSTP1 were significantly higher in the Biopsy than in the Reference Group. For all three genes the percentage of outlier scores was greater in the Biopsy than in the Reference Group but reached statistical significance only for GSTP1. A comparison between the biopsied and non-biopsied breasts of the Biopsy Group revealed higher mean methylation and a greater number of outlier scores in the biopsied breast for both SFRP1 and RASSF1, but not for GSTP1. This is the first evidence of CpG island methylation in tumor suppressor genes of women who may be at increased risk of developing breast cancer based on having had a prior breast biopsy.

Over the past 20 years, numerous research studies have been published indicating that lesbian, gay, and bisexual (LGB) individuals, LGB couples, and family members of LGB individuals are experiencing religious identity/sexual orientation identity conflict. In addition, many of these same studies have included in the findings resolution strategies utilized by participants to negotiate this type of conflict. This article presents a review of the religious identity/sexual orientation identity conflict research and links it to cognitive dissonance theory. Subsequently, implications for counselors and future research are offered in light of this literature review.

Manipulation of ploidy in switchgrass has potential to accelerate inbred production and to provide insight about genome structure through either sequencing or cytogenetic approaches. We have identified two dihaploid individuals isolated from among the progeny of a controlled cross between two individuals of the cultivars Alamo and Kanlow. The dihaploid lines were initially distinguished from the parental lines by their reduced heterozygosity and were subsequently confirmed through estimation of C values by flow cytometry and chromosome counts of metaphase root tip squash preparations. These plants are functionally sterile, with floral bracts that remain closed and inviable pollen. They can be easily distinguished from tetraploid individuals by their reduced stature, smaller epidermal cell size, and lower number of chloroplasts per guard cell. Aberrant meiosis in these individuals is evidenced by a lack of regular pairing at diakinesis and metaphase I and suggests that the non-homologous genomes are distinct from one another. The reduced genome size of these dihaploids will facilitate basic genome studies and genetic analyses that are impossible or problematic in polyploid accessions.

The focus of this work was to evaluate the use of commercially available matting systems to sustain C-130 and C-17 transport aircraft loads over soil bases having different California bearing ratio (CBR) ranges. Test sections were constructed using three range of CBR: high (CBR=40–50), medium (CBR=8–10), and low (CBR=5–6). Testing began with the C-130 load cart and six different matting systems. The C-130 was the lesser of the two aircraft loads examined and this initial testing was used as an "elimination round" for the various matting systems chosen. Matting systems deemed suitable for the C-130 were further tested under the C-17 load cart. Systems were evaluated based on logistical and assembly requirements, mat damage sustained during traffic, and accumulated deformation of the mats and soil during traffic. The latter are shown in line plots of passes versus plastic rut formation. Summary information on each matting system tested and the test sections themselves is presented. Conclusions on the matting systems tested and their application are discussed.

Purpose Poor living conditions are posited as an underlying cause of American Indian (AI) infant mortality, which is unusually high in the postneonatal period. We explore whether the effects of neighborhood poverty on AI infant death are identifiable by using observational data. Methods Vital records for infants born between 1990 and 1999 to AI women in a metropolitan area (n = 4751) are linked with tract-level poverty data. A counterfactual framework, an explicit causal contrast study design, and propensity score matching methods were used. For each comparison, we created exchangeable groups by matching infants with the same probability of exposure to poverty when one was exposed and the other was not. Results Our results suggest that neighborhood poverty has little effect on AI infant death outcomes. Importantly, the study design makes transparent the challenge of identifying appropriate analytic comparison groups in studies of neighborhood poverty and health. Conclusions Collecting additional data will likely not overcome the fact that AIs with a high probability of living in poverty rarely reside in low-poverty neighborhoods. Yet, some of them must if a meaningful counterfactual comparison is to be made and the effects of neighborhood poverty on AI infant death are to be identified.

In this study, we investigate the extent to which women and men differ in patterns of medication use, based on quantitative and qualitative data from a household survey in Western Massachusetts. Using a broad definition of medications, 96% of the sample reported taking one or more medications in the month preceding the survey (86% if vitamins, supplements, and alternative medications are excluded). Twenty-one percent of respondents reported taking five or more medications, and women were significantly more likely to report taking five or more medications in the month preceding the survey. For both sexes, analgesics and vitamins were the most commonly used medications, but women were more likely to report having taken hormones, supplements, and antihistamines. The likelihood of medicating reported health conditions did not differ by sex, but the frequency of reporting health conditions was higher among women, and the difference was significant for body aches and psychosomatic conditions. Analyses of qualitative data indicate that female networks of relatives and friends are an important source of advice on medications for both men and women. Responses to open-ended questions suggest that women's discourse about the effect of medications differs from men's in terms of the range and detail of descriptions of symptoms and side effects.

Historical mortality analysis is often confounded by changing disease environments, diagnostic criteria, and terminology. Recorded causes of death are shaped by these local and historical contexts. We analyze changing literal causes of death during the shift from miasmatic to germ theories of disease using death records from two Massachusetts towns for selected years spanning 1850 to 1912. This analysis demonstrates that (1) International Classification of Diseases (ICD) classifications are more stable, yet potentially less informative, than the literal causes recorded in death accounts, (2) recorded causes of death often include additional qualifications and elaborations beyond basic literal causes of death, and the use of such qualifiers rose dramatically during the late nineteenth century, (3) social biases are clearly evident in the extent to which causes of death were further described or qualified, and (4) the additional descriptive qualification of deaths during this period of often ambiguous historical causes of death can potentially aid in efforts to classify causes of death and derive robust estimates of cause-specific mortality trends.

The present paper focuses on the economic evaluation of the observed differences in maternal productivity of different genetic lines in Angus cattle that were managed under contrasting nutritional regimes typical of southern Australia. Five hundred Angus cows were managed concurrently at two locations in southern Australia. On each site, the cows were managed under the following two different nutritional treatments: High and Low, to simulate different stocking rates. Cows selected for a divergence in either carcass rib-fat depth or residual feed intake based on mid-parent estimated breeding values for those traits, were allocated in replicate groups to either High- or Low-nutrition treatments. By design, the supplementary feeding regime was the same for the High and Low genetic lines to ensure genetic differences were not confounded with management differences. Animal productivity results from the experiment were used as input data to evaluate the economic performance of the four genetic lines under the two nutritional treatments. Two methods were used; the first was a gross-margin calculation of income minus variable costs as AU$ per breeding cow for a 1000-cow herd; the second was a whole-farm linear programming model maximising the gross margin. Stocking rates were optimised by matching the energy requirements for the whole herd with the energy available from pasture and supplementary feed on a representative 700-ha farm. Using the two methods of calculating gross margin (per cow and optimised per hectare), including examination of sensitivity to changes in prices of cattle and supplementary feed, the present study demonstrated that genetically leaner cows due to selection of low fat or low residual feed intake, had gross margins superior to those of genetically fatter cows. They generated more income by selling more liveweight due to heavier weights and higher stocking rates. The results are affected by the management system utilised and some confounding with growth (leaner genetic lines had higher growth estimated breeding values), but will assist producers to make more informed decisions about how to manage animal breeding and nutritional interactions.

A finite-element analysis was conducted of flexible pavement test sections subjected to a moving aircraft tire. The test sections failed primarily as a result of shear in the base course. Excavation of the test sections at the end of the tests revealed that there was transverse shear flow of the base as a result of repetitive loading. Deflections at various depths were recorded with multidepth deflectometers. These deflections were used to calibrate the finite-element model. Subsequently, excellent agreement was obtained between measured and predicted time histories of deflections at the various depths. Also, excellent agreement was obtained between predicted and accumulated rutting. The analysis predicted that the shear stress in the base would equal the shear strength, which confirms the mode of failure observed in the test sections.

Erythropoietin enhances vascular responsiveness to norepinephrine in renal failure. The mechanism of hypertension induced by recombinant human erythropoietin (rHuEPO) is unclear but may include an increase in peripheral vascular resistance. We studied changes of arterial pressure and plasma endothelin in nine consecutive hemodialysis patients before, and 6 and 12 weeks after, starting rHuEPO. In six patients, changes in cardiac index (CI), stroke index (SI) and total peripheral resistance index (TPRI) were measured by bioimpedance, and forearm vascular responsiveness to intra-arterial norepinephrine (30 to 240 pmol/min) and endothelin-1 (5 pmol/min) were assessed. Six healthy age and sex matched subjects also underwent assessment of forearm vascular responsiveness to norepinephrine and endothelin-1. Treatment with rHuEPO significantly increased hemoglobin and mean arterial pressure (MAP). TPRI also increased by 35 ± 11%. Plasma endothelin, although elevated basally, remained unchanged. Intra-arterial infusion of norepinephrine caused a maximal increase in forearm vascular resistance (FVR) of 17 ± 9% before rHuEPO, significantly less than the 32 ± 5% increase in healthy control subjects (P = 0.04). The response increased to 65 ± 15% (P = 0.03) after 12 weeks rHuEPO treatment (P = 0.51 vs. controls). Endothelin-1 caused a maximal increase of FVR at 60 minutes of 45 ± 24% before rHuEPO, which was not significantly different from controls, and tended to decrease with rHuEPO therapy. The response to endothelin-1, but not norepinephrine, correlated inversely with MAP (r = -0.52; P = 0.03) and TPRI (r = -0.51; P = 0.04). In conclusion, these studies show that anemia in chronic renal failure is associated with depressed vascular responsiveness to norepinephrine which is restored by rHuEPO therapy. In contrast, vascular responses to endothelin-1 tend to reduce with rHuEPO therapy. The change in vascular responsiveness to norepinephrine may contribute to the increase in arterial pressure associated with rHuEPO therapy.

Research addressing “environmental equity” and “environmental racism” claims that facilities for treatment, storage, and disposal of hazardous wastes (TSDFs) are located disproportionately in minority areas. In the first comprehensive study of TSDFs to use census tract-level data, we find no nationally consistent and statistically significant differences between the racial or ethnic composition of tracts which contain commercial TSDFs and those which do not. TSDFs are more likely to be found in tracts with Hispanic groups, primarily in regions with the greatest percentage of Hispanics. Different geographic units of analysis elaborate on, but are consistent with, these results.

To investigate the trunk strength of elite rowers and the impact of low back pain on these measures in order to determine if asymmetries or weakness were present.Twenty two elite rowers were recruited: 13 reported previous low back pain, five current low back pain, and the remainder had no history of low back pain. All subjects were scanned during simulated rowing in an interventional open magnetic resonance imaging scanner. In each simulated rowing position, axial scans were obtained at the level of the L4-5 and L5-S1 disc interspace to determine the cross sectional area of the posterior trunk muscles.Considerable differences were observed between the three groups of rowers. In contrast with expectations and previous literature, the trunk muscles of rowers with low back pain had significantly larger cross sectional areas (p0.001). No left/right asymmetries were observed and no differences between oarside and non-oarside in terms of muscle cross sectional area.These findings suggest that low back pain in rowers does not arise as a result of muscle weakness.

Promoter methylation analysis of genes frequently silenced in breast cancer is a promising indicator of breast cancer risk, as these methylation events are thought to occur long before presentation of disease. The numerous exfoliated epithelial cells present in breast milk may provide the breast epithelial DNA needed for detailed methylation analysis and assessment of breast cancer risk. Fresh breast milk samples and health, lifestyle, and reproductive history questionnaires were collected from 111 women. Pyrosequencing analysis was conducted on DNA isolated from the exfoliated epithelial cells immunomagnetically separated from the total cell population in the breast milk of 102 women. A total of 65 CpG sites were examined in six tumor suppressor genes: PYCARD (also known as ASC or TMS1), CDH1, GSTP1, RBP1 (also known as CRBP1), SFRP1, and RASSF1. A sufficient quantity of DNA was obtained for meaningful analysis of promoter methylation; women donated an average of 86 ml of milk with a mean yield of 32,700 epithelial cells per ml. Methylation scores were in general low as expected of benign tissue, but analysis of outlier methylation scores revealed a significant relationship between breast cancer risk, as indicated by previous biopsy, and methylation score for several CpG sites in CDH1, GSTP1, SFRP1, and RBP1. Methylation of RASSF1 was positively correlated with women's age irrespective of her reproductive history. Promoter methylation patterns in DNA from breast milk epithelial cells can likely be used to assess breast cancer risk. Additional studies of women at high breast cancer risk are warranted.

Many local agencies that provide services to the homeless have only limited data and resources to estimate the extent of need or the size of the local population at risk of requiring the services they provide. Methods exist, however, that are capable of providing reasonable estimates of underlying service populations with minimal record keeping. In this paper one group of such models, first‐capture models, is discussed as a resource‐efficient technique for estimating the underlying population consistently at risk ("residents") and those occasionally at risk ("transients") of requiring agency services.

This paper evaluates age, period, and cohort effects on marital fertility during onset of the Utah fertility transition (1880–1909). Computerized genealogies are used to derive age–period–cohort fertility rates for 49,842 once-married couples. Age, period and cohort effects on marital fertility are then estimated using Johnson's (1985) relational model. Declining marital fertility in Utah is shown to be explained by both lower fertility levels across periods and increasing age-specific limitation across cohorts. Direct cohort effects on fertility are insignificant. These results are consistent with prior research, and the view that fertility levels were adaptive (in part through birth spacing across ages) to immediate contexts of childbearing while age-specific fertility truncation increased across cohorts (in part through the more general diffusion of contraceptive innovations).

Research addressing "environmental equity" and "environmental racism" claims that facilities for treatment, storage, and disposal of hazardous wastes (TSDFs) are located disproportionately in minority areas. In the first comprehensive study of TSDFs to use census tract-level data, we find no nationally consistent and statistically significant differences between the racial or ethnic composition of tracts which contain commercial TSDFs and those which do not. TSDFs are more likely to be found in tracts with Hispanic groups, primarily in regions with the greatest percentage of Hispanics. Different geographic units of analysis elaborate on, but are consistent with, these results.

"This paper evaluates age, period, and cohort effects on marital fertility during onset of the Utah fertility transition (1880-1900). Computerized genealogies are used to derive age-period-cohort fertility rates for 49,842 once-married couples. Age, period and cohort effects on marital fertility are then estimated using Johnson's (1985) relational model. Declining marital fertility in Utah is shown to be explained by both lower fertility levels across periods and increasing age-specific limitation across cohorts. Direct cohort effects on fertility are insignificant. These results are consistent with prior research, and the view that fertility levels were adaptive (in part through birth spacing across ages) to immediate contexts of childbearing while age-specific fertility truncation increased across cohorts (in part through the more general diffusion of contraceptive innovations)."

Average yield of wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) in the high rainfall cropping zone (>750 mm) of south Western Australia from 1996 to 2001 was 2.5 t/ha. This is far below the water-limited potential yield (water losses of 110 mm, transpiration efficiency of 20 kg/ha.mm) of 6–8 t/ha. Nutrition of the cereal crops has been regarded as one constraint to reaching the potential yield, although grain yield increases (responses) under conventional management practices (a series of full cultivation operations) have been inconsistent. Three experiments, with a total of five trial sites conducted over two seasons, were carried out to test the response of wheat and barley to fertiliser applications of nitrogen (N), phosphorus (P), potassium (K), sulfur (S) and trace elements (TE). Various combinations of nutrients were applied. These ranged from no fertiliser (nil), to farmer practice (N at rates at 34–82 kg/ha, P at 3–17 kg/ha, K at 0–50 kg/ha and S at 4–11 kg/ha), to nutrients calculated to supply the needs of a 6–8 t/ha cereal crop (N, P, K, S, TE). The aim was to determine whether the supply of non-limiting levels of crop nutrients could raise yields to the potential yield as determined by seasonal rainfall. In the drier seasons experienced in 2001 and 2002 at Arthur River and Cranbrook, with growing season rainfall (May–November) up to about 350 mm, it was possible to raise grain yields to levels at or above the calculated rainfall-limited potential with increased nutrition (4.2 t/ha for barley and 4.5 t/ha for wheat). However, in the wetter environment of Boyup Brook in 2002, where seasonal rainfall was greater than 500 mm, extra nutrition by itself was not sufficient to reach the water-limited potential, even where the yields were increased from 3.5 to 5.2 t/ha for wheat and from 3.9 to 4.5 t/ha for barley. Further experimentation is required to clarify the factors limiting responses to nutrition when the growing season rainfall is greater than 500 mm and thus allow greater confidence in extrapolating these results in the high rainfall cropping zone of Western Australia. In wheat, the highest profits were obtained from the complete fertiliser strategy (N, P, K, S, TE). However, for barley, the greatest profits were not obtained with the highest grain yields and fertiliser strategies due to decreased grain quality.

This article presents an analysis of the effect that urban secularization of religious pronatalism had upon established birth spacing behavior over the course of the fertility transition in the population of 19th century Utah. A model of variance in birth intervals attributable to age at marriage age of childbearing termination and completed family size over the duration of childbearing thus defined is presented. The simple analytical model achieves a reasonable fit for birth interval data. In addition the model demonstrates the relative dependence of birth intervals upon the fertility achieved over the duration of childbearing rather than upon deliberate control over the beginning or ending of the childbearing interval. Variations in age at marriage become more important in explaining birth intervals than do variation in age at last birth. The model is elaborated by incorporating 5 specific hypotheses concerning the effects of urbanism secularization and their interaction upon interbirth intervals. 2 principal conclusions were derived. 1) Birth interval differentials among subcohorts defined by religiosity and urbanism are generally consistent with fertility effects of traditional urbanism and secularization perspectives. 2) There is however no consistent evidence that this frontier population was as heterogeneous in the secularization of traditional pronatalism as is often the case in either European or 3rd world settings. Although a pattern of urban secularization is found uniformity of social and behavioral changes suggestsa that relatively homogeneous demographic behavior was produced on the frontier by the largely external locus of secularizing influences in the mainstream eastern American community.

Data from a large survey of federal employees is utilized to compare three broad competing perspectives that suggest effects on sexual harassment within organizations. Three different viewpoints stress power differentials, minority status, and diffuse master status characteristics. Results of the study indicate that intraorganizational theories emphasizing either power inequalities or work group compositional heterogeneities are unable to account for the reported sexual harassment without considering diffuse master status characteristics developed and maintained outside the organization.

Summary— A group of 128 consecutive patients was identified on whom renal isotope studies had been performed during the first 2 months after renal transplantation and within 7 days of transplant biopsy. The prospective renogram and biopsy reports were reviewed and graded into 4 categories: severe rejection, predominant rejection, predominant acute tubular necrosis (ATN) and pure ATN. Two extreme patterns of renogram were identified: a sharp rise with a fast decline in the first min, attributed to ATN, and a slowly rising curve with no early peak occurring in severe rejection although not specific to this condition. There was a continuous intermediate spectrum. There was no inter-observer variation in gradings at the 2 ends of the spectrum. In the middle part the difference between 2 independent observers never exceeded more than 1 grade. There was good correlation between the biopsy and renogram gradings, with a discrepancy of more than 1 grade in only 5 patients; 2 of these, with severe rejection on the renogram, showed predominant ATN on biopsy, but the final clinical diagnosis was severe rejection (false positive biopsies). Two patients with biopsies showing severe rejection had a sharp initial up-slope in the renograms but a slower down-slope (over 4 min compared with 1 min in true ATN). With better definition of the criteria these renograms would not have been graded as ATN. There was 1 patient in whom no satisfactory explanation for the discrepancy was found (presumed false positive renogram). When properly defined criteria are used to interpret renograms, this simple test is at least as reliable as renal biopsy in differentiating ATN from rejection in the early post-transplant period, especially in the presence of anuria or severe oligurea.

Postural changes in plasma renin activity were studied in three groups of age and duration-matched male diabetics (potent, impotent and with postural hypotension) and in non-diabetic control subjects. Those diabetic subjects with postural hypotension due to automatic neuropathy had no increase in plasma renin activity to the erect posture whereas both the potent and impotent groups had similar plasma renin activity responses to the control subjects. There was a significant inverse correlation between the rise in plasma renin activity on standing and the postural drop in blood pressure (r = 0.476, P less than 0.01) but no correlation with other tests of autonomic reflex function such as the Valsalva manoeuvre and blood pressure response to sustained handgrip. The results suggested that the lesion responsible for the postural hypotension is in the efferent sympathetic pathway. However, neuropathy per se did not wholly explain the decreased postural plasma renin activity response. Diabetic nephropathy, with involvement of cells of juxtaglomerular apparatus, may also be implicated.

Some 200 ML of water are reused tn Los Angeles and Orange counties each day for a variety of uses. Spurred by a statewide drought some two years ago, area water and wastewater utilities conducted the Orange and Los Angeles Counties Water Reuse Study, which revealed that long-term reuse potential for the region is 1150 ML/d. The study spawned a lo-year project plan that would expand reuse applications and make water reuse an official part of the California Water Plan.

The sampling designs used in organizational research have been less than consistent across different reported studies. In this analysis we examine the reported relationships among several key organizational variables in ten separate previously published studies to determine the degree to which major differences in sample designs have influenced findings. We isolate that portion of reported associations due to unique characteristics of the samples and report the association these ‘sample design effects’ have with particular sample designs. Results indicate homogeneous samples of organizations inflate reported relationships yet leave significant sources of variation uncontrolled in sample selection. an alternative to sampling of homogeneous organizations is suggested by the fact that larger and probabilitistically selected samples are also associated with larger reported relationships among organizational variables.

The results of a longitudinal study assessing the impact of internal constraints upon both organizational responsiveness to the environment and efforts to change structures for symbolic signaling of policy are presented. The causal model used is developed from a theoretical elaboration of Williamson, Thompson, and Meyer. The implications of the analysis for the signaling metaphor of organizational change are emphasized. The data indicate (i) that the varying resistance to change observed within core dimensions of organizational structure may be largely due to durable capital investments, (ii) that within capitalized dimensions of organizational structure, the resulting resistance to change leads to a longitudinal persistence of centralized decision making, and (iii) that failure to incorporate such constraints in analyses of organizational change leads to misleading results.

Intermarriage among heterogeneous social groups has often been studied as a process of assimilation. The present paper extends this research through a unique application of macro-structural propositions of intermarriage (Blau et al., 1982) to a nineteenth century American frontier population. Variants of these propositions are presented, used to address age patterns of nuptiality, and tested through a longitudinal application. Results support the utility of macro-structural theories in analyses encompassing initial community formation as well as assimilation of later arriving immigrants. Analyses illustrate both the assimilation of initially arriving immigrant groups on the frontier and the initial emergence of new heterogeneities in the established native population and later arriving immigrants.

The fall in blood base occurring after the administration of secretin and the aspiration of duodenal contents was assessed in normal patients and in patients with chronic pancreatitis. In contrast to normal patients, those with chronic pancreatitis showed only a small fall or no fall in blood base level. There was no correlation between the amount of bicarbonate as determined by aspiration and that calculated from the blood base change. In 3 normal patients the magnitude of the renal compensatory mechanism in the post-secretin hour was found to be insignificant.

The antiplatelet drug ticlopidine was assessed as an agent for improving the patency of Brescia-Cimino arteriovenous fistulas as access for hemodialysis. In a double-blind randomized study over 1 month, two of six fistulas in the ticlopidine group and five of nine in the placebo group failed. A further one placebo and two ticlopidine patients still had functioning fistulas at the time of withdrawal for technical reasons from the trial. Ticlopidine appears, therefore, to enhance the efficacy of Brescia-Cimino fistulas, at least in the short term.