Development of Simplified Models of Water Quality in Lignite Mining Areas

The development of complex decision support model systems for the analysis of regional water policies for regions with intense socio-economic development effecting and being affected by the water resources system is of increasing importance. One of the most illustrative examples are regions with open-pit lignite mining. Such model systems have to be based on appropriate submodels e.g. for water quality processes. The paper describes submodel for groundwater and surface water quality with special regard to open-pit lignite mining regions. We consider the discharge of acid ferruginous water into rivers as having the most important impact on water quality in open-pit lignite mining areas. One goal of the model system is the choice of the necessary degree of purification for mine water treatment plants, taking into account self-purification in rivers and remaining pits as well as the water quality demand of down-stream water users. Based on comprehensive water quality models, the development of which is described in the paper, the possibilities for the derivation of reduced models are described. Those model have been elaborated for groundwater, as the source of pollution, mine water treatment plants as control units, river sections with an intake of acid ferruginous water, and remaining pits, which can also serve as effective control units. Related with each other, these models form the complex system model, a system of differential equations. They were numerically solved. The computer program is included in the paper

Antifactor Xa activity in critically ill patients receiving antithrombotic prophylaxis with standard dosages of certoparin: a prospective, clinical study

INTRODUCTION: Deep venous thrombosis with subsequent pulmonary embolism or post-thrombotic syndrome is a feared complication in the intensive care unit. Therefore, routine prophylactic anticoagulation is widely recommended. Aside from unfractionated heparin, low molecular weight heparins, such as certoparin, have become increasingly used for prophylactic anticoagulation in critically ill patients. In this prospective study, we evaluated the potency of 3,000 IU certoparin administered once daily to reach antithrombotic antifactor Xa (aFXa) levels of 0.1 to 0.3 IU/ml in 62 critically ill patients. METHODS: AFXa levels were determined 4, 12 and 24 h after injection of certoparin. Prothrombin time, activated partial thromboplastin time, antithrombin, fibrinogen, hemoglobin, platelet count, serum urea and creatinine concentrations were documented before and 12 and 24 h after injection of certoparin. RESULTS: Four hours after certoparin injection (n = 32), 28% of patients were within the antithrombotic aFXa range. After 12 and 24 h, 6% achieved antithrombotic aFXa levels. Because of a severe pulmonary embolism in one study patient, an interim analysis was performed, and the dosage of certoparin was increased to 3,000 IU twice daily. This regime attained recommended antithrombotic aFXa levels in 47%, 27%, 40% and 30% of patients at 4, 12, 16 and 24 h, respectively, after twice daily certoparin injection (n = 30). Antithrombin and fibrinogen concentrations slightly increased during the observation period. Low antithrombin concentrations before certoparin were independently correlated with underdosing of certoparin. Patients with aFXa levels <0.1 IU/ml 4 h after certoparin injection required vasopressors more often and had lower serum concentrations of creatinine and urea than patients with antithrombotic aFXa levels. CONCLUSION: Standard dosages of certoparin of 3,000 IU given once or twice daily are ineffective for attaining the recommended aFXa levels of 0.1 to 0.3 IU/ml in critically ill patients. Low antithrombin levels before certoparin administration were independently associated with low aFXa levels. Renal function and vasopressor therapy may further influence the effectiveness of certoparin in ensuring adequate antithrombotic prophylaxis

Paraphrases and summaries: A means of clarification or a vehicle for articulating a preferred version of student accounts?

The use of group discussions as a means to facilitate learning from experiences is well documented in adventure education literature. Priest and Naismith (1993) assert that the use of the circular discussion method, where the leader poses questions to the participants, is the most common form of facilitation in adventure education. This paper draws on transcripts of facilitation sessions to argue that the widely advocated practice of leader summaries or paraphrases of student responses in these sessions functions as a potential mechanism to control and sponsor particular knowledge(s). Using transcripts from recorded facilitation sessions the analysis focuses on how the leader paraphrases the students’ responses and how these paraphrases or ‘formulations’ function to modify or exclude particular aspects of the students’ responses. I assert that paraphrasing is not simply a neutral activity that merely functions to clarify a student response, it is a subtle means by which the leader of the session can, often inadvertently or unknowingly, alter the student’s reply with the consequence of favouring particular knowledge(s). Revealing the subtle work that leader paraphrases perform is of importance for educators who claim to provide genuine opportunities for students to learn from their experience

Avaliação de grupos genéticos em sistema de produção leiteiro intensivo a pasto no Acre.

O objetivo deste estudo foi avaliar o uso de grupos genéticos bovinos para produção de leite em sistema intensivo de pastagem no Acre. Foram utilizados dados de produção leiteira de 46 matrizes do grupo genético Girolando e 59 do cruzamento Nelore x Holandesa denominado Nelorando em propriedade localizada no município de Rio Branco, AC. Foram analisados os parâmetros de produção de leite, intervalo entre partos, duração de lactação e produção de leite ajustada para 270 dias de 167 lactações com 1.499 controles de produção diária agrupados em quatro épocas do ano de controle. As estimativas dos parâmetros genéticos foram obtidas pelo método REML/BLUP. A média estimada para produção de leite aos 270 dias de lactação e o desvio-padrão foram de 2.474,70 ± 256,52 para o grupo Girolando e 2.542,03 ± 269,36 para o grupo Nelorando com médias diárias de produção e desvio-padrão de 9,28 ± 2,49 e 10,23 ± 2,8, respectivamente. O intervalo entre partos médio encontrado na propriedade foi 12,85 meses (12,88 para Girolando e 12,83 para Nelorando). A duração de lactação para o grupo Girolando foi de 288,13 dias e para Nelorando de 273,47 dias. Para os parâmetros estudados não houve diferença significativa entre os grupos. Conclui-se que os grupos genéticos não divergem entre si e os efeitos ambientais são contornados quando se faz uso de tecnologias que favorecem a uniformidade de forrageiras com boa qualidade nutricional.Editores técnicos: Rodrigo Souza Santos; Fabiano Marçal Estanislau

Arterial blood pressure during early sepsis and outcome

OBJECTIVE: To evaluate the association between arterial blood pressure (ABP) during the first 24 h and mortality in sepsis. DESIGN: Retrospective cohort study. SETTING: Multidisciplinary intensive care unit (ICU). PATIENTS AND PARTICIPANTS: A total of 274 septic patients. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: Hemodynamic, and laboratory parameters were extracted from a PDMS database. The hourly time integral of ABP drops below clinically relevant systolic arterial pressure (SAP), mean arterial pressure (MAP), and mean perfusion pressure (MPP = MAP - central venous pressure) levels was calculated for the first 24 h after ICU admission and compared with 28-day-mortality. Binary and linear regression models (adjusted for SAPS II as a measure of disease severity), and a receiver operating characteristic (ROC) analysis were applied. The areas under the ROC curve were largest for the hourly time integrals of ABP drops below MAP 60 mmHg (0.779 vs. 0.764 for ABP drops below MAP 55 mmHg; P or = 60 mmHg may be as safe as higher MAP levels during the first 24 h of ICU therapy in septic patients. A higher MAP may be required to maintain kidney function

Structural features and kinetic characterization of alanine racemase from Staphylococcus aureus (Mu50)

The tertiary structure and kinetic properties of alanine racemase from Staphylococcus aureus are described and compared to other related alanine racemase structures

Socio-economic status is inversely related to bed net use in Gabon

This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens

Perioperative infusion of low- dose of vasopressin for prevention and management of vasodilatory vasoplegic syndrome in patients undergoing coronary artery bypass grafting-A double-blind randomized study

Preoperative medication by inhibitors of angiotensin-converting enzyme (ACE) in coronary artery patients predisposes to vasoplegic shock early after coronary artery bypass grafting. Although in the majority of the cases this shock is mild, in some of them it appears as a situation, "intractable" to high-catecholamine dose medication. In this study we examined the possible role of prophylactic infusion of low-dose vasopressin, during and for the four hours post-bypass after cardiopulmonary bypass, in an effort to prevent this syndrome. In addition, we studied the influence of infused vasopressin on the hemodynamics of the patients, as well as on the postoperative urine-output and blood-loss. In our study 50 patients undergoing coronary artery bypass grafting were included in a blind-randomized basis. Two main criteria were used for the eligibility of patients for coronary artery bypass grafting: ejection fraction between 30-40%, and patients receiving ACE inhibitors, at least for four weeks preoperatively. The patients were randomly divided in two groups, the group A who were infused with 0.03 IU/min vasopressin and the group B who were infused with normal saline intraoperativelly and for the 4 postoperative hours. Measurements of mean artery pressure (MAP), central venous pressure (CVP), systemic vascular resistance (SVR), ejection fracture (EF), heart rate (HR), mean pulmonary artery pressure (MPAP), cardiac index (CI) and pulmonary vascular resistance (PVR) were performed before, during, and after the operation. The requirements of catecholamine support, the urine-output, the blood-loss, and the requirements in blood, plasma and platelets for the first 24 hours were included in the data collected. The incidence of vasodilatory shock was significantly lower (8% vs 20%) in group A and B respectively (p = 0,042). Generally, the mortality was 12%, exclusively deriving from group B. Postoperatively, significant higher values of MAP, CVP, SVR and EF were recorded in the patients of group A, compared to those of group B. In group A norepinephrine was necessary in fewer patients (p = 0.002) and with a lower mean dose (p = 0.0001), additive infusion of epinephrine was needed in fewer patients (p = 0.001), while both were infused for a significant shorter infusion-period (p = 0.0001). Vasopressin administration (for group A) was associated with a higher 24 hour diuresis) (0.0001)