1,800 research outputs found

    Mobilisation or dilution? Nitrate response of karst springs to high rainfall events

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    peer-reviewedNitrate (NO3−) contamination of groundwater associated with agronomic activity is of major concern in many countries. Where agriculture, thin free draining soils and karst aquifers coincide, groundwater is highly vulnerable to nitrate contamination. As residence times and denitrification potential in such systems are typically low, nitrate can discharge to surface waters unabated. However, such systems also react quickest to agricultural management changes that aim to improve water quality. In response to storm events, nitrate concentrations can alter significantly, i.e. rapidly decreasing or increasing concentrations. The current study examines the response of a specific karst spring situated on a grassland farm in South Ireland to rainfall events utilising high-resolution nitrate and discharge data together with on-farm borehole groundwater fluctuation data. Specifically, the objectives of the study are to formulate a scientific hypothesis of possible scenarios relating to nitrate responses during storm events, and to verify this hypothesis using additional case studies from the literature. This elucidates the controlling key factors that lead to mobilisation and/or dilution of nitrate concentrations during storm events. These were land use, hydrological condition and karstification, which in combination can lead to differential responses of mobilised and/or diluted nitrate concentrations. Furthermore, the results indicate that nitrate response in karst is strongly dependent on nutrient source, whether mobilisation and/or dilution occur and on the pathway taken. This will have consequences for the delivery of nitrate to a surface water receptor. The current study improves our understanding of nitrate responses in karst systems and therefore can guide environmental modellers, policy makers and drinking water managers with respect to the regulations of the European Union (EU) Water Framework Directive (WFD). In future, more research should focus on the high-resolution monitoring of karst aquifers to capture the high variability of hydrochemical processes, which occur at time intervals of hours to days.Teagasc Walsh Fellowship Programm

    Fair and Square?: An examination of the relationships among classroom justice and relational teaching messages

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    Students and instructors acknowledge the importance of the instructor–student relationship in the classroom. Despite the importance of the instructor–student interpersonal relationship, there can also be unexpected or undesirable outcomes associated with relational teaching. Using the theoretical framework of leader–member exchange, we explored relational teaching messages to understand how they may relate positively or negatively to student perceptions of classroom justice. Participants (N = 124) completed measures about relational communication strategies (i.e., rapport, confirmation, and affinity-seeking) and classroom justice (i.e., procedural, interactional, and distributive). Results indicate the enjoyable interaction dimension of rapport positively predicted perceptions of all three types of justice. The response to questions dimension of confirmation positively predicted perceptions of procedural and interactional justice

    Relationship between vascularity, age and survival in non-small-cell lung cancer.

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    Lung tumours in the elderly show reduced growth potential; impaired angiogenesis may contribute to this phenomenon. Recent studies have suggested that the angiogenic potential of a tumour may be inferred by the vascularity measured in histological sections. The purpose of this study has been to determine whether vascularity is related to age, survival or other clinical parameters in resected non-small-cell lung cancer (NSCLC). A group of 88 consecutive patients with a follow-up period of at least 5 years was selected. The group exhibited a wide age range (37-78 years) and similar survival characteristics to those of the general NSCLC population. Tumour sections were stained with a pan-endothelial antibody (vWF) and vascularity was quantitated, without knowledge of the clinical details, by three methods: highest microvascular density; average microvascular density; and average microvascular volume. The results were analysed by non-parametric statistical tests. A correlation was found between all three methods of quantitation. Vascularity was not associated with age, sex, tumour type, stage, volume, size (TNM-T) nodal status (TNM-N) or survival. However, survival time was generally longer for patients with higher vascularity, reaching borderline significance (P = 0.06) for the average microvascular density values. Higher tumour volume (P = 0.02) and stage (P = 0.05) were associated with lower survival times. Using multivariate survival analysis, tumour volume was the only factor related to survival. We conclude that vascularity is not associated with age and has no significant prognostic value in NSCLC

    The relationship between psychological distress and multiple tender points across the adult lifespan

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    Multiple tender points are common in the population and, in studies of mid-life adults, are strongly associated with high levels of psychological distress. Whether this relationship occurs in older adults is unclear. This cross-sectional study investigated whether high levels of psychological distress would be associated with a high tender point count and whether the relationship would be moderated by age. Three thousand three hundred and seventy-nine individuals were mailed a questionnaire which included the Hospital Anxiety and Depression (HAD) scale, the Pain Catastrophising Scale (PCS), the Brief Illness Perception Questionnaire (Brief IPQ), and the Pittsburgh Sleep Quality Index (PSQI). A random sample of approximately 10% of subjects who returned the questionnaire undertook a physical assessment, including a manual tender point count assessment.A total of 2385 (71%) subjects completed the questionnaire, of whom 798 (33%) were invited to take part in the physical assessment and 290 (12%) participated. Of the 290 participants the median age was 64 years (range 34-97) and 63% were female. The median HAD score was 9 (IQR 5-14) and the median number of tender points was 3 (range 0-7).Increasing HAD score was positively and significantly associated with tender point count, but this relationship was not moderated by age. In a final multivariable model, sex, HAD score and PSQI score were independent predictors of multiple tender points.Psychological distress was associated with multiple tender points independent of age. Psychological distress and trouble sleeping were important, potentially modifiable factors associated with the outcome

    Management of Colonic Trauma: Six-Year Experience at Henry Ford Hospital

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    Surgical management of 114 patients with colonic injuries related to trauma who were treated over a six-year period is reviewed. Eighty-three (73%) injuries were secondary to gunshot wounds. Twenty-six patients (24%) had isolated colonic injuries. The majority of patients (60%)) were treated with colostomies: exteriorization of the injury, repair with proximal colostomy, or resection with colostomy and mucous fistula. Exteriorization of repaired colon, primary repair, and resection with primary anastomosis were performed in 40% of the patients. Six patients (5.3%) in our series died, and 24% had complications directly related to the colon injury. Based on this study, no standard method for treatment of colonic trauma is advised. Colostomy is recommended for patients with massive multiple intra-abdominal injuries and gross fecal contamination. In selected patients, primary repair may be performed

    First Experimental Demonstration of Full-Duplex Optical Communications on a Single Laser Beam

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    We present the results of the first experimental demonstration a novel communications architecture that will be deployed on a Space Shuttle mission in 2003. This architecture can provide a very lightweight, low power consumption, low data rate communications link between the earth and LEO satellites. A unique characteristic of this system is that it provides full-duplex communications on a single beam is presented. The results of first experiments demonstrating this full duplex communications architecture are presented

    'Tumour volume' as a predictor of survival after resection of non-small-cell lung cancer (NSCLC)

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    Many factors have been individually related to outcome in populations of non-small-cell lung cancer (NSCLC) patients. Factors responsible for the outcome of an individual after surgical resection are poorly understood. We have examined the importance of 'tumour volume' in determining prognosis of patients following resection of NSCLC in a multivariate model. Cox's proportional hazard analysis was used to determine the relative prognostic significance of stage, patient age, gender, tumour cell-type, nodal score and estimated 'tumour volume' in 669 cases with NSCLC treated with surgical resection, of which 280 had died. All factors (except tumour cell-type, P = 0.33) were individually related to survival (P < 0.05). When examined together, survival time was significantly and independently related to 'tumour volume' and stage (P < 0.001), and other factors ceased to be significant. In cases with stage I or II tumours, risk of death was found to increase significantly with increasing estimated 'tumour volume' (23.8% relative increase in hazard to death per doubling of 'tumour volume', 95% confidence interval 13.2-35.2%, P < 0.001 stage I; P < 0.006 stage II). In cases with stage IIIa tumours this factor alone was the significant prognostic variable. In conclusion, an estimate of 'tumour volume' significantly improves prediction of prognosis for individual NSCLC patients with UICC stage I or II tumours
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