Electrical Discharge from a Thundercloud Top to the Lower Ionosphere

Nature. Mar, 2002  |  Pubmed ID: 11894087

For over a century, numerous undocumented reports have appeared about unusual large-scale luminous phenomena above thunderclouds and, more than 80 years ago, it was suggested that an electrical discharge could bridge the gap between a thundercloud and the upper atmosphere. Since then, two classes of vertically extensive optical flashes above thunderclouds have been identified-sprites and blue jets. Sprites initiate near the base of the ionosphere, develop very rapidly downwards at speeds which can exceed 107 m s-1 (ref. 15), and assume many different geometrical forms. In contrast, blue jets develop upwards from cloud tops at speeds of the order of 105 m s-1 and are characterized by a blue conical shape. But no experimental data related to sprites or blue jets have been reported which conclusively indicate that they establish a direct path of electrical contact between a thundercloud and the lower ionosphere. Here we report a video recording of a blue jet propagating upwards from a thundercloud to an altitude of about 70 km, taken at the Arecibo Observatory, Puerto Rico. Above an altitude of 42 km-normally the upper limit for blue jets and the lower terminal altitude for sprites-the flash exhibited some features normally observed in sprites. As we observed this phenomenon above a relatively small thunderstorm cell, we speculate that it may be common and therefore represent an unaccounted for component of the global electric circuit.

Bioterrorism in Australia

The Medical Journal of Australia. Mar, 2002  |  Pubmed ID: 11999254

Impact of Single Dose Azithromycin on Group A Streptococci in the Upper Respiratory Tract and Skin of Aboriginal Children

The Pediatric Infectious Disease Journal. May, 2002  |  Pubmed ID: 12150171

Aboriginal children living in remote Australia experience high rates of bacterial infection such as trachoma, otitis media and streptococcal skin infection, which often progress to associated chronic diseases in later life.

In Vivo Penicillin MIC Drift to Extremely High Resistance in Serotype 14 Streptococcus Pneumoniae Persistently Colonizing the Nasopharynx of an Infant with Chronic Suppurative Lung Disease: a Case Study

Antimicrobial Agents and Chemotherapy. Nov, 2002  |  Pubmed ID: 12384383

This is the first report of in vivo pneumococcal penicillin MIC drift from 4.0 to 16.0 mg/liter, possibly associated with alterations in the pbp1a gene. The case presented here is of an infant with early onset recurrent pneumonia and chronic bronchitis requiring repeated antibiotics.

Robust Estimation of Fetal Heart Rate Variability Using Doppler Ultrasound

IEEE Transactions on Bio-medical Engineering. Aug, 2003  |  Pubmed ID: 12892322

This paper presents a new measure of heart rate variability (HRV) that can be estimated using Doppler ultrasound techniques and is robust to variations in the angle of incidence of the ultrasound beam and the measurement noise. This measure employs the multiple signal characterization (MUSIC) algorithm which is a high-resolution method for estimating the frequencies of sinusoidal signals embedded in white noise from short-duration measurements. We show that the product of the square-root of the estimated signal-to-noise ratio (SNR) and the mean-square error of the frequency estimates is independent of the noise level in the signal. Since varying angles of incidence effectively changes the input SNR, this measure of HRV is robust to the input noise as well as the angle of incidence. This paper includes the results of analyzing synthetic and real Doppler ultrasound data that demonstrates the usefulness of the new measure in HRV analysis.

The Management of Diabetic Retinopathy

The Practitioner. Jan, 2004  |  Pubmed ID: 14997740

A Mathematical Basis for the Application of the Modified Geometric Method to Maximum Frequency Estimation

IEEE Transactions on Bio-medical Engineering. Nov, 2004  |  Pubmed ID: 15536910

The application of ultrasound in assessing the fetal cardiovascular system often requires the accurate estimation of maximum blood flow velocity waveforms using Doppler measurements. The modified geometric method estimates the maximum Doppler frequency as the frequency at which the vertical distance between the integrated spectrum and the reference line that connects the origin to the maximum value of the integrated spectrum is the largest. This paper presents a mathematical formulation for a class of maximum blood flow velocity estimation algorithms that includes the modified geometric method. The analysis provides a rationale for the continued use of the modified geometric method for estimating the maximum frequency envelopes of Doppler signals. This paper also contains experimental results demonstrating the superiority of the modified geometric method over a commonly used threshold crossing method.

Autoimmune Pancreatitis--an Uncommon Type of Chronic Pancreatitis

Indian Journal of Gastroenterology : Official Journal of the Indian Society of Gastroenterology. Sep-Oct, 2004  |  Pubmed ID: 15599002

Autoimmune pancreatitis is a recently recognized clinical entity characterized by narrow strictured main pancreatic duct on ERCP, diffusely enlarged sausage-shaped pancreas on CT scan and MRI, seropositivity for antinuclear antibodies, hypergammaglobulinemia, and excellent response to steroids. We report a 25-year-old man and a 53-year-old man with this condition.

Preseptal Cellulitis Caused by Acinetobacter Lwoffi

Indian Journal of Ophthalmology. Sep, 2005  |  Pubmed ID: 16137978

Application of the Magnitude-squared Coherence Function Between Uterine and Umbilical Flow Velocity Waveforms for Predicting Placental Dysfunction: a Preliminary Study

Ultrasound in Medicine & Biology. Jul, 2007  |  Pubmed ID: 17448590

To examine whether the magnitude-squared coherence between uterine and umbilical blood flow velocity waveforms can, in conjunction with estimated fetal weight, uterine and umbilical pulsatility indices, fetal and maternal heart rates, diastolic notching and the amniotic fluid index, create a sensitive and specific model for the prediction of placental dysfunction. Binary logistic prediction models are created for preeclampsia, pregnancy induced hypertension and intrauterine growth restriction in a study group of 284 unselected midtrimester pregnancies. In each study group, the median value of derived parameters were compared with the uncomplicated pregnancy control group. The magnitude-squared coherence function between the uterine and umbilical flow velocity waveforms was found to be a statistically significant predictor of preeclampsia during the midtrimester of pregnancy. The magnitude-squared coherence did not improve the prediction of intrauterine growth restriction or pregnancy induced hypertension. The inclusion of magnitude-squared coherence as one of the prediction parameters may improve the early identification of pregnancies subsequently complicated by preeclampsia.

A Biological Model for Influenza Transmission: Pandemic Planning Implications of Asymptomatic Infection and Immunity

PloS One. 2007  |  Pubmed ID: 18043733

The clinical attack rate of influenza is influenced by prior immunity and mixing patterns in the host population, and also by the proportion of infections that are asymptomatic. This complexity makes it difficult to directly estimate R(0) from the attack rate, contributing to uncertainty in epidemiological models to guide pandemic planning. We have modelled multiple wave outbreaks of influenza from different populations to allow for changing immunity and asymptomatic infection and to make inferences about R(0).

Compared to Placebo, Long-term Antibiotics Resolve Otitis Media with Effusion (OME) and Prevent Acute Otitis Media with Perforation (AOMwiP) in a High-risk Population: a Randomized Controlled Trial

BMC Pediatrics. 2008  |  Pubmed ID: 18513453

For children at high risk of chronic suppurative otitis media (CSOM), strategies to prevent acute otitis media with perforation (AOMwiP) may reduce progression to CSOM.

Review. The Changing Face of Kuru: a Personal Perspective

Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences. Nov, 2008  |  Pubmed ID: 18672465

The epidemic of kuru is now known to have been transmitted among the Fore by ritual consumption of infected organs from deceased relatives. As cannibalism was suppressed by government patrol officers during the 1950s, most transmission had ceased by 1957, when the kuru research programme first commenced. As predicted in the 1960s, the epidemic has waned, with progressive ageing of kuru-affected cohorts over the years to 2007. The few cases seen in the twenty-first century, with the longest incubation periods, were almost certainly exposed as children prior to 1960. Although the research programme had almost no role in bringing the kuru epidemic to an end, it did provide important knowledge that was to help the wider world in controlling the later epidemics of iatrogenic and variant Creutzfeldt-Jakob disease and bovine spongiform encephalopathy.

End-stage Kidney Failure in Indigenous Australians

Australian and New Zealand Journal of Public Health. Aug, 2008  |  Pubmed ID: 18782389

Understanding Influenza Transmission, Immunity and Pandemic Threats

Influenza and Other Respiratory Viruses. Jul, 2009  |  Pubmed ID: 19627371

The current pandemic threat can be best understood within an ecological framework that takes account of the history of past pandemics caused by influenza A, the relationships between pandemic and seasonal spread of influenza viruses, and the importance of immunity and behavioural responses in human populations. Isolated populations without recent exposure to seasonal influenza seem more susceptible to new pandemic viruses, and much collateral evidence suggests that this is due to immunity directed against epitopes shared between pandemic and previously circulating strains of inter-pandemic influenza A virus. In the highly connected modern world, most populations are regularly exposed to non-pandemic viruses, which can even boost immunity without causing influenza symptoms. Such naturally-induced immunity helps to explain the low attack-rates of seasonal influenza, as well as the moderate attack-rates in many urbanized populations affected by 1918-1919 and later pandemics. The effectiveness of immunity, even against seasonal influenza, diminishes over time because of antigenic drift in circulating viruses and waning of post-exposure immune responses. Epidemiological evidence suggests that cross-protection against a new pandemic strain could fade even faster. Nevertheless, partial protection, even of short duration, induced by prior seasonal influenza or vaccination against it, could provide important protection in the early stages of a new pandemic.

Influenza: Accounting for Prior Immunity

Science (New York, N.Y.). Aug, 2009  |  Pubmed ID: 19713508

Amelanotic Melanoma Presenting with Cervical Lymphadenopathy

BMJ Case Reports. 2009  |  Pubmed ID: 21686931

We present a rare case of an amelanotic melanoma of unknown primary presenting with cervical lymphadenopathy. A 20-year-old man presented with large left sided neck lump, associated dysphagia and weight loss. Examination revealed a hard mass in the left posterior triangle of neck and sacral sensory loss. Fine needle aspiration cytology of the mass suggested a poorly differentiated carcinoma. Computed tomography showed a left sided, 8×13 cm cervical mass with liver, lung and bony metastases. Histological examination of the lymph nodal mass confirmed the diagnosis of a metastatic amelanotic melanoma. The patient was treated with glucocorticoids, radiation therapy for the sacral bony deposit, and chemotherapy. Despite an initial reduction of his target lesions, his condition subsequently deteriorated and he died 4 months after diagnosis.

Low-dose Cyclosporine Treatment for Sight-threatening Uveitis: Efficacy, Toxicity, and Tolerance

Indian Journal of Ophthalmology. Jan-Feb, 2010  |  Pubmed ID: 20029146

To ascertain the effectiveness, tolerability, and safety of low-dose cyclosporine in the management of sight-threatening uveitis.

Exudative Retinal Detachment Following Photodynamic Therapy for Retinal Capillary Hemangioma

Canadian Journal of Ophthalmology. Journal Canadien D'ophtalmologie. Jun, 2010  |  Pubmed ID: 20436538

Prior Immunity Helps to Explain Wave-like Behaviour of Pandemic Influenza in 1918-9

BMC Infectious Diseases. 2010  |  Pubmed ID: 20497585

The ecology of influenza may be more complex than is usually assumed. For example, despite multiple waves in the influenza pandemic of 1918-19, many people in urban locations were apparently unaffected. Were they unexposed, or protected by pre-existing cross-immunity in the first wave, by acquired immunity in later waves, or were their infections asymptomatic?

Understanding Mortality in the 1918-1919 Influenza Pandemic in England and Wales

Influenza and Other Respiratory Viruses. Mar, 2011  |  Pubmed ID: 21306572

The causes of recurrent waves in the 1918-1919 influenza pandemic are not fully understood.

Multiple-input Single-output Closed-loop Isometric Force Control Using Asynchronous Intrafascicular Multi-electrode Stimulation

IEEE Transactions on Neural Systems and Rehabilitation Engineering : a Publication of the IEEE Engineering in Medicine and Biology Society. Jun, 2011  |  Pubmed ID: 21385670

Although asynchronous intrafascicular multi-electrode stimulation (IFMS) can evoke fatigue-resistant muscle force, a priori determination of the necessary stimulation parameters for precise force production is not possible. This paper presents a proportionally-modulated, multiple-input single-output (MISO) controller that was designed and experimentally validated for real-time, closed-loop force-feedback control of asynchronous IFMS. Experiments were conducted on anesthetized felines with a Utah Slanted Electrode Array implanted in the sciatic nerve, either acutely or chronically ( n = 1 for each). Isometric forces were evoked in plantar-flexor muscles, and target forces consisted of up to 7 min of step, sinusoidal, and more complex time-varying trajectories. The controller was successful in evoking steps in force with time-to-peak of less than 0.45 s, steady-state ripple of less than 7% of the mean steady-state force, and near-zero steady-state error even in the presence of muscle fatigue, but with transient overshoot of near 20%. The controller was also successful in evoking target sinusoidal and complex time-varying force trajectories with amplitude error of less than 0.5 N and time delay of approximately 300 ms. This MISO control strategy can potentially be used to develop closed-loop asynchronous IFMS controllers for a wide variety of multi-electrode stimulation applications to restore lost motor function.

Post-streptococcal Glomerulonephritis is a Strong Risk Factor for Chronic Kidney Disease in Later Life

Kidney International. Feb, 2012  |  Pubmed ID: 22297679

Although unusual in western countries and in Australia in general, post-streptococcal glomerulonephritis (PSGN) is still common in Australian Aboriginal children living in remote communities. Here, we evaluated whether episodes of acute PSGN increased the risk for chronic kidney disease in later life in 1519 residents of a remote Aboriginal community (85% of those age eligible), with high rates of renal and cardiovascular disease, who participated in a health screen over a 3-year period. Of these, 200 had had at least one episode of PSGN, with 27 having had multiple episodes, usually in childhood. High levels of albuminuria (albumin/creatinine ratio) with increasing age were confirmed. All PSGN episodes were associated with group A streptococcal skin infections, often related to scabies. In both genders, aged 10-39 years at screening, about one in five had such a history. Among them, PSGN (5 years or more earlier) was significantly associated with higher levels of albuminuria than those without. In women, aged 30-39 years, a history of PSGN was associated with a significantly higher frequency of estimated glomerular filtration rates <60 ml/min. The adjusted odds ratios for an albumin/creatinine ratio over 34 g/mol (overt albuminuria) in males and females with a history of PSGN were 4.6 and 3.1, respectively, compared with those without a history. Thus, PSGN contributes to the very serious burden of chronic kidney disease in this community. Rigorous strategies to prevent scabies and Group A streptococcal infections will reduce this burden.Kidney International advance online publication, 1 February 2012; doi:10.1038/ki.2011.478.