Time and dose dependency of bone-sarcomas in patients injected with radium-224

The time course and dose dependency of the incidence of bone-sarcomas among 900 German patients treated with high doses of radium-224 is analysed in terms of a proportional hazards model with a log-normal dependency of time to tumor and a linear-quadratic dose relation. The deduced dose dependency agrees well with a previous analysis in terms of a non-parametric proportional hazards model, and confirms the temporal distribution which has been used in the Radioepidemiological Tables of NIH. However, the linear-quadratic dose-response model gives a risk estimate for low doses which is somewhat less than half that obtained under the assumption of linearity. Dedicated to Prof. W. Jacobi on the occasion of his 60th birthday Work performed under Euratom contracts BI6-D-083-D, BI6-F-111-D, U.S. Department of Energy contract DE-AC 02-76 EV-00119, the U.S. National Cancer Institut

Evaluation of cover crops in high tunnel vegetable rotation

Organic vegetable production within high tunnels allows for an extended growing season, crop protection, and environmental control. The USDA National Organic Program (NOP) standards mandate evidence that the soil has been maintained and improved over the course of production. Previous studies have indicated the potential of cover crops for reducing competitive vegetation, and improving soil quality, thus resulting in greater plant growth, nutrient uptake, and yield. However, there has been limited work in the confines of high tunnels as part of a tunnel-system rotation. Ten nitrogen-fixing and ten non-legume cover crops were established under a high tunnel and evaluated for their effects on the yield of ‘De Cicco’ broccoli (Brassica oleracea L. var. italica) and ‘Champion’ collards (Brassica oleracea L. var. acephala), aboveground biomass, and plant C and N contents. All treatments received recommended levels of appropriate certified organic fertilizers, water status was maintained, and vegetables received standard organic maintenance for insects and disease. The cover crops hairy indigo (Indigofera hirsuta L.), Catjang cowpea (Viana unguicalata L.), and Sunn hemp (Crotalaria juncea L.) consistently produced higher yields than Tifleaf III hybrid pearl millet (Pennisetum glaucum L.), Dairymaster brown midrib (BMR) hybrid grain sorghum (Sorghum spp.), and Wild Game Food sorghum (Sorghum bicolor L.). Nitrogenfixing legumes produced horticulturally significantly higher yields than the non-nitrogen-fixing grass species. This experiment demonstrated that not all cover crops are equal; they created variation in response. Cover crops provide a viable option for organic producers to maintain or improve soil quality over the course of production

Solute Transport and U(VI) Reactivity in Natural Heterogeneous Sediments

The primary goal of this research was to determine the relationship between sedimentary geology and solute transport parameters. The overall hypothesis was that the transport of reactive and nonreactive solutes can be predicted using observable sedimentary depositional characteristics. The objective was to test this hypothesis by performing a variety of quantitative transport experiments in intact layered sediment samples. In this study, I used natural materials to explore 1) how mineralogical composition influenced the fate and transport of uranium(VI), 2) the relationship between heterogeneous sedimentary layering and preference for direction of flow, and 3) the mechanisms of solute transport in a partially-saturated cross-bedded sand. In Chapter 2, uranium(VI) sorption to siliciclastic and carbonate sediments was quantified using batch isotherm, kinetic, and miscible displacement experiments. Uranium(VI) sorption was small (Kd \u3c 1), most likely due to the formation of stable anionic and neutral U(VI)-CO3 complexes and competition for sorption sites by dissolved carbonate. Sorption to carbonate- containing sediments was consistently greater than to siliciclastic sediments. Selective extractions and kinetic studies suggested that U(VI) may have co-precipitated with calcite in carbonate sediments, while X-ray absorption spectroscopy suggested that U(VI) reversibly adsorbed to iron oxides and clay minerals in siliciclastic sediments. In Chapter 3, saturated miscible displacement was applied to intact flow bedding parallel (pb) and flow across bedding (xb) samples from six different sedimentary facies. Hydraulic and transport parameters varied over 4 orders of magnitude. Hydraulic and transport parameters (dispersivity, hydraulic conductivity) were slightly anisotropic, i.e., varied with direction of flow with respect to sedimentary bedding. Anisotropy increased predictably with the proportion of fine-grained material, suggesting that flow and/or solute transport across fine-grained beds may have been restricted in comparison to parallel to bedding. In Chapter 4, solute transport in partially-saturated, fine-grained and cross-bedded sediments was influenced by local-scale perching associated with flow across sedimentary layering. The arrivals of the wetting front and nonreactive tracers were concurrent, but the elution of tracers occurred well before the cores became fully saturated. This was suggestive of preferential flow, but changes in the volume of water inside the cores prevented the confirmation of such mechanisms. A reversed pattern of multiple nonreactive tracers was observed, which was characteristic of flow through restrictive media, i.e., media with low hydraulic conductivity. Overall, these results provided quantitative evidence to relate subsurface geology and contaminant transport. My findings will improve the conceptual and quantitative understanding of flow and transport in vadose zones composed of complex layered sediments

Explaining the persistent dominance of the Greek medical profession across successive health care system reforms from 1983 to the present

The Greek medical profession played an important role at the start of the Greek National Health System (NHS) in 1983 and became intrinsic to its later development. In particular, junior hospital doctors firmly established their position and rights as a result of the new NHS. Using archival sources and interviews with elite participants, this article investigates the specific patterns of power and influence that Greek NHS doctors have exerted from the establishment of the Greek NHS through the latest major attempt at reform in 2001 to the present. Hospital doctors, in particular, have been able consistently to resist any health care system reforms that might affect their dominant position. Their unchallenged position in the system derives from both the particularities of the Greek state and society (in particular, the former’s founding institutional arrangements and the latter’s clientelistic social relations) and the key role that junior doctors played in the early stages of the Greek NHS. As a result, the system is highly path dependent in that the initial implementation of the NHS during the 1980s ensured that subsequent reforms consistently favored the self-interest of medical doctors. Though challenges to the unaccountable power of the medical profession have emerged in Greece following the financial crisis of 2009, including the beginnings of a popular critique of the medical profession, it is too soon to tell whether these will succeed in bringing about significant change

African American women in public higher education administrative leadership in the state of Missouri: perspectives on a half century of progress

This study explores the lived experiences of six African American female administrators in Missouri public higher educational institutions. The Black Feminist Thought theory as espoused by Patricia Collins is the framework with which this research examines their leadership. The conceptual lens of race, gender, and class offers an opportunity to see strength and empowerment as these women face oppression with a conqueror's attitude. The ways in which these women are empowered to employ leadership and use their positional authority is reflected in the three themes, knowledge, consciousness, and the politics of empowerment. Interviews were conducted with the participants using open-ended questions. They were questions about their positional authority, the cultural climate, political climate, and challenges as African American female administrators. They were also asked to make recommendations to Missouri institutions. The themes that emerged where: 1) racism, 2) sexism, 3) gender equity, 4) disrespect of knowledge, 5) lack of diversity, 6) isolation, and 7) lack of recruitment and retention efforts . Yet, with these emerging themes, the participants were empowered to continue to perform their duties, because students need what they have to offer, perseverance, advocacy, and role models

New Zealand's new health sector reforms: back to the future?

New Zealand attracted much international attention in the late 1980s and 1990s for its radical economic and social reforms. This reforming tendency shows no signs of abating. In late 1999 the national (conservative) government was replaced by a Labour led coalition, which is rapidly and significantly changing the way publicly financed health services are organised. Before the general election, Labour had criticised the national government's quasimarket system for its narrow focus on the production of services rather than the improvement of health, for having fragmented a public service, for fostering inappropriate commercial behaviour, for increasing transaction costs, and for lacking local democratic input. These problems were attributed to the "corporate model" of public hospital provision and a single, national purchasing agency. Both will now be replaced with a system promoted as allowing greater community "voice" in health sector decision making and "putting the public back into the public health system." This paper reviews New Zealand's experience with the quasimarket model and appraises the rationale for another round of structural change. We identify challenges policymakers face in achieving their goals, consider the general lessons provided by New Zealand's frequent U-turns in policy, and offer a set of criteria against which the new system might be assessed

Designing a Successful Practice-Based Research Network in Public Health: Key Concepts

Successful public health practice-based research networks (PBRNs) will require organizational, financial, and intellectual resources that allow practitioners and researchers to mount relevant studies in real-world public health settings. This brief outlines characteristics likely to be important to the success of public health PBRNs, based on the experience of PBRNs in other practice setting

Interpretations of referral appropriateness by senior health managers in five PCT areas in England: a qualitative investigation

AIM: To explore interpretations of "appropriate" and "inappropriate" elective referral from primary to secondary surgical care among senior clinical and non-clinical managers in five purposively sampled primary care trusts (PCTs) and their main associated acute hospitals in the English National Health Service (NHS). METHODS: Semi-structured face-to-face interviews were undertaken with senior managerial staff from clinical and non-clinical backgrounds. Interviews were tape-recorded, transcribed and analysed according to the Framework approach developed at the National Centre for Social Research using N6 (NUD*IST6) qualitative data analysis software. RESULTS: Twenty-two people of 23 approached were interviewed (between three and five respondents per PCT and associated acute hospital). Three attributes relating to appropriateness of referral were identified: necessity: whether a patient with given characteristics was believed suitable for referral; destination or level: where or to whom a patient should be referred; and quality (or process): how a referral was carried out, including (eg, investigations undertaken before referral, information contained in the referral and extent of patient involvement in the referral decision. Attributes were hierarchical. "Necessity" was viewed as the most fundamental attribute, followed by "destination" and, finally, "quality". In general, but not always, all three attributes were perceived as necessary for a referral to be defined as appropriate. CONCLUSIONS: For senior clinical and non-clinical managers at the local level in the English NHS, three hierarchical attributes (necessity, appropriateness of destination and quality of referral process) contributed to the overall concept of appropriateness of referral from primary to secondary surgical care