Effects of old landfills on groundwater quality. Phase 2, investigation of the Thriplow landfill 1996–1997

Disused sand and gravel excavations overlying the major Chalk aquifer at Thriplow in Cambridgeshire have been filled with domestic waste in two phases. One area (Phase 1) was filled between 1957–77 with little compaction of the refuse and was left uncapped, while Phase 2 was deposited between 1981–87 and capped with clay. Aerial photography and surface resistivity surveys indicate that the site geometry is complex, with several phases of landfilling into excavations of differing depths. Drilling through the waste indicates that leachate production and waste stabilisation proceed at different rates in capped and uncapped landfills. Analysis of leachate obtained by centrifugation or squeezing appears to give more insight into the pollution potential than do leach tests with distilled water. The Biological Methane Potential (BMP) of the waste appears to be related to the quantity of decomposable material but the chemical oxygen demand (COD) values are distorted by the presence of reduced metals. Too few boreholes have been drilled to define the leachate source in terms of its spatial distribution and little is known of how its composition has changed with time. However, hydraulic conductivity measurements on the landfill caps suggest that it is sufficiently permeable for all rainfall to potentially infiltrate the waste. Boreholes outside the landfill penetrate the Upper and Lower Chalk, and identify the Melbourn Rock and underlying Plenus Marls at the junction of the two formations about 20 m below ground level (bgl). Surface resistivity surveys using the BGS RESCAN system, confirm aerial photographs of the extent of the landfill and also suggest that leachate has migrated beyond the base of the landfill. Evidence of leachate migration in pre-existing screened boreholes completed above and below the Plenus Marls suggests that leachate is flowing above the Plenus Marls. Hydraulic head measurements whilst drilling a borehole to the base of the lower Chalk approx. 70 m bgl revealed the potential for upward groundwater flow through the Plenus Marls. Thus, previously-drilled boreholes penetrating the Plenus Marls are expected to recharge upwards into the shallow aquifer above the Plenus Marls diluting any leachate in the upper aquifer and distorting the flow regime. Several of these boreholes have subsequently been modified to stem the flow across the Plenus Marls. One borehole down-gradient to the west of the site revealed a large thickness of drift composed of both sand and clay rich material. This suggests the existence of a buried channel, the hydrogeological significance of which has yet to be assessed. Groundwater chemistry appears to be influenced by three major factors. (a) the landfill leachate (b) the composition of shallow groundwater in the top 10 m of the Chalk, and (c) the composition of water from the Lower Chalk. Limited groundwater monitoring data appear to display a cyclic variation in chloride concentration. The origin for this is not clear but it may correlate with cyclic variations in groundwater levels when the water table rises into the waste. Cyclic flushing of the landfill may release leachate into the aquifer giving rise to pulses of chloride. Alternatively changes in chloride may arise by the changing direction of groundwater flow which as yet has not been assessed. A conceptual hydrogeological model in which flow is limited to above the Plenus Marls has been used to develop a more appropriate groundwater flow and solute transport model. However, the model lacks data on aquifer properties, on contaminant inputs concentrations, fluxes and spatial variations, and there is a paucity of monitoring data for calibration. Nonetheless preliminary transport modelling using an equivalent porous medium approach shows that an effective porosity of about 5% best fits the regional data. Since this is much less than the total porosity of about 40% for the Chalk, it would appear that only part of the Chalk is available for flow but that matrix diffusion could play an important role in leachate attenuation. Discrete fracture modelling using the FRACTRAN code has allowed some scoping to be made of the hydraulic properties of the aquifer by comparison with chloride hydrographs, but these again need to be better conditioned by in-situ measurement of fracture distributions and transmissivities. A number of additional activities are required to improve the understanding of flow and contaminant transport at the site. These include better spatial definition of the waste distribution, improved data on the hydraulic properties of the Chalk aquifer, and the use of automatic monitoring to record temporal changes in groundwater chemistry and groundwater levels

Mixed response to immunotherapy in patients with metastatic melanoma

Background Immunotherapy has improved overall survival in metastatic melanoma. Response to therapy can be difficult to evaluate as the traditionally used RECIST 1.1 criteria do not capture heterogeneous responses. Here we describe the clinical characterization of melanoma patients with a clinically defined mixed response to immunotherapy. Methods This was a single institution, retrospective analysis of stage IV melanoma patients who received first-line anti-CTLA-4, anti-PD1, or combination anti-CTLA-4/anti-PD1. Therapy response was assessed via clinical definitions, which consisted of cross-sectional imaging combined with clinical exam. Course of disease, clinicopathological characteristics, and management in patients with a mixed clinical response were analyzed. Results In 292 patients (anti-CTLA4 = 63; anti-PD1 = 148, anti-CTLA4/anti-PD1 = 81), 103 were responders (35%), 64 mixed responders (22%), and 125 patients had progressive disease (43%). Of patients with a mixed response, 56% eventually had response to therapy (mixed response followed by response, MR-R), while 31% progressed on therapy (MR-NR). MR-NR patients had higher median LDH (p = 3 organ sites with metastases. Surgical treatment for highly selected patients with a mixed response was associated with improved outcomes.Surgical oncolog

Differences in the pattern and regulation of mineral deposition in human cell lines of osteogenic and non-osteogenic origin

Bone marrow-derived mesenchymal stem cells (MSCs) are widely used as a cellular model of bone formation, and can mineralize in vitro in response to osteogenic medium (OM). It is unclear, however, whether this property is specific to cells of mesenchymal origin. We analysed the OM response in 3 non-osteogenic lines, HEK293, HeLa and NTera, compared to MSCs. Whereas HEK293 cells failed to respond to OM conditions, the 2 carcinoma-derived lines NTera and HeLa deposited a calcium phosphate mineral comparable to that present in MSC cultures. However, unlike MSCs, HeLa and NTera cultures did so in the absence of dexamethasone. This discrepancy was confirmed, as bone morphogenetic protein inhibition obliterated the OM response in MSCs but not in HeLa or NTera, indicating that these 2 models can deposit mineral through a mechanism independent of established dexamethasone or bone morphogenetic protein signalling

Why is management research irrelevant?

At least since 1980, there has been a practically continuous, but somewhat fragmented discussion on the relevance of management research. This discussion has addressed practically all fields of management; here, besides general management, operations management, project management and construction management are examined in more detail. Although many different proposals have been made to rectify the situation, no definitive resolution has been found. In this paper, it is argued that prior analyses have not reached the root causes of the irrelevance problem. By an analysis of the recent history of management research, the following novel findings are reached. First, the root cause of the irrelevance is argued to lie in the 1959 reports on American business education, written by Pierson and Gordon & Howell. Second, while the proposed direction in the 1959 reports was deficient in several ways, the rejection of production as an integral part of organizations and management has been perhaps the most damaging feature of those reports. Third, current research on management suffers from a variety of immediate causes for irrelevance, insufficiently recognized by the scholarly community. It is suggested that reaching the root causes for irrelevance will facilitate finding suitable cures

Analysis of shared heritability in common disorders of the brain

Paroxysmal Cerebral Disorder

The Cholecystectomy As A Day Case (CAAD) Score: A Validated Score of Preoperative Predictors of Successful Day-Case Cholecystectomy Using the CholeS Data Set

Background Day-case surgery is associated with significant patient and cost benefits. However, only 43% of cholecystectomy patients are discharged home the same day. One hypothesis is day-case cholecystectomy rates, defined as patients discharged the same day as their operation, may be improved by better assessment of patients using standard preoperative variables. Methods Data were extracted from a prospectively collected data set of cholecystectomy patients from 166 UK and Irish hospitals (CholeS). Cholecystectomies performed as elective procedures were divided into main (75%) and validation (25%) data sets. Preoperative predictors were identified, and a risk score of failed day case was devised using multivariate logistic regression. Receiver operating curve analysis was used to validate the score in the validation data set. Results Of the 7426 elective cholecystectomies performed, 49% of these were discharged home the same day. Same-day discharge following cholecystectomy was less likely with older patients (OR 0.18, 95% CI 0.15–0.23), higher ASA scores (OR 0.19, 95% CI 0.15–0.23), complicated cholelithiasis (OR 0.38, 95% CI 0.31 to 0.48), male gender (OR 0.66, 95% CI 0.58–0.74), previous acute gallstone-related admissions (OR 0.54, 95% CI 0.48–0.60) and preoperative endoscopic intervention (OR 0.40, 95% CI 0.34–0.47). The CAAD score was developed using these variables. When applied to the validation subgroup, a CAAD score of ≤5 was associated with 80.8% successful day-case cholecystectomy compared with 19.2% associated with a CAAD score >5 (p < 0.001). Conclusions The CAAD score which utilises data readily available from clinic letters and electronic sources can predict same-day discharges following cholecystectomy

Farmers' organizations, poverty and the envrionment in the Sertao, North-East Brazil

Item does not contain fulltext23 september 1997Promotor : Kleinpenning, J.M.G. Co-promotor : Ros-Tonen, M.A.F.232 p

Farmers' organizations, poverty and the envrionment in the Sertao, North-East Brazil

Item does not contain fulltext23 september 1997Promotor : Kleinpenning, J.M.G. Co-promotor : Ros-Tonen, M.A.F.232 p

Non-governmental organisations in development

Item does not contain fulltex