293 research outputs found
Ocean acoustic circumpropagation in the ice seas of Europa
No full textIn recent years increased attention has been paid to the potential uses of acoustics forextraterrestrial exploration. A number of important papers have discussed propagationon Europa, primarily with respect to sound in the ice sheet which is believed to covera salt water ocean. The models used to date assume a flat ice surface and agravitational acceleration which does not vary with depth. Models of long rangeacoustic propagation through Europa’s ice seas require models which do not makethese two assumptions. This report applies such a model to simple Europangeometries to show how observables can be affected by the values of physicalparameters: the report considers the specific case of the effect on the travel time of acircumpropagating pulse of the ice and water thicknesses, and water temperature(assumed to be uniform), on a simple spherical planet. Such effects could be the basisof acoustic inversion experiments, although it is recognised that the complexities anduncertainties associated with the actual ice seas of Europa would make the task verymuch more challenging than the calculations undertaken in this simple study
An acoustical hypothesis for the spiral bubble nets of humpback whales and the implications for whale feeding
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Intensive insulin treatment
No full textHyperglycaemia is common in acute illness and more severe hyperglycaemia is associated with worse outcomes in critically ill patients in general and after acute myocardial infarction, stroke, and trauma. Normalization of blood glucose by intensive insulin therapy has been shown to reduce morbidity and mortality in one study in surgical intensive care patients; a subsequent study in medical intensive care patients resulted in reduced morbidity but not a reduction in mortality. Multicentre studies and current meta-analyses in the critically ill have not demonstrated improved outcomes when normalization of blood glucose was targeted; furthermore all studies to date have detected an increased risk of hypoglycaemia in patients subjected to intensive insulin therapy. At present, universal treatment guidelines or recommendations to target strict normoglycaemia must be considered premature. Further data will be available after the completion of the NICE-SUGAR study which has recruited 6103 patients; the NICE SUGAR study will add significant power to future meta-analyses and may help define the role of intensive insulin therapy in critically ill patients
Pathophysiology and causes of haemoptysis
No full textThe main goal of management of pleural effusion is to provide symptomatic relief removing fluid from pleural space and the options depend on type, stage and underlying disease. The first diagnostic instrument is the chest radiography while ultrasound can be very useful to guide thoracentesis. Pleural effusion can be a transudate or an exudate. Generally a transudate is uncomplicated effusion treated by medical therapy, while an exudative effusion is considered complicated effusion and should be managed by drainage. Refractory non-malignant effusions can be transudative (congestive heart failure, cirrhosis, nephrosis) or exudative (pancreatitis, connective tissue disease, endocrine dysfunction), and the management options include repeated therapeutic thoracentesis, indwelling pleural catheter for intermittent external drainage, pleuroperitoneal shunts for internal drainage, or surgical pleurectomy. Parapneumonic pleural effusions can be divided in complicated when there is persistent bacterial invasion of the pleural space, uncomplicated and empyema with specific indications for pleural fluid drainage. Malignancy is the most common cause of exudative pleural effusions in patients aged >60 years and the decision to treat depends upon the presence of symptoms and the underlying tumour type. Options include indwelling pleural catheter drainage, pleurodesis, pleurectomy and pleuroperitoneal shunt. Hemothorax needs to be differentiated from a haemorrhagic pleural effusion and when is suspected the essential management is the intercostal drainage. It achieves two objectives to drain the pleural space allowing expansion of the lung and to allow assessment of rates of blood loss to evaluate the need for emergency or urgent thoracotomy
Pathophysiology and therapeutic strategy of respiratory alkalosis
No full textRespiratory alkalosis is a condition characterized by low partial pressure of carbon dioxide and an associated elevation in arterial pH caused by an imbalance between CO2 production and removal, in favour of the latter. Conditions that cause increased alveolar ventilation, without having a reduction in pH as input stimulus, will cause hypocapnia associated with a variable degree of alkalosis. The major effect of hypocapnia is the increase in pH (alkalosis) and the consequent shift of electrolytes that occurs in relation to it. As a general law, in plasma, anions will increase, while cations will decrease. The acute reduction in ionized calcium, due to the change in extracellular pH, may cause neuromuscular symptoms ranging from paraesthesias, to tetany and seizures. The effect on urine is an increase in urinary strong ion difference/urinary anion gap and a consequent increase in urinary pH. Finally, acute hypocapnic alkalosis causes a constriction of cerebral arteries that can lead to a reduction of cerebral blood flow. The clinical approach to respiratory alkalosis is usually directed toward the diagnosis and treatment of the underlying clinical disorder
An ultrasound based passive monitoring system for extracorporeal shock wave lithotripsy (ESWL)
No full textDiagnosis, assessment and management of tetanus, rabies and botulism
No full text<b>Key Points</b>\ud
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- Tetanus and botulism are caused by neurotoxins whereas rabies is a viral zoonosis.\ud
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- Clostridium tetani exotoxins cause the syndrome of tetanus which is characterized by generalized muscle rigidity, autonomic instability and sometimes convulsions. Without expensive intensive care treatment the disease is often fatal\ud
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- Good wound care, metronidazole and symptomatic care are important to provide a good outcome , and as the disease does not produce immunity, active immunization with antitetanus toxin must follow.\ud
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- Botulism is a toxin related illness generally the result of food poisoning leading to an ascending paralysis with neural destruction. Recovery is prolonged and often with persisting weakness especially where mechanical ventilation has been required.\ud
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- Rabies and associated Lyssavirus infection is uncommon but with potential reservoirs in may countries. Encephalitic disease in the previously unimmunized is a fatal illness
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