33 research outputs found
Properties of the Magnetosphere over the 11-Year Solar Cycle
The magnetosphere refers to the region encompassing a planet and its magnetic field. For Earth specifically, our magnetic field is shaped by the onslaught of streams of charged particles from the sun known as solar wind. Solar wind collides with the magnetic field of the earth and is deflected by it, deforming the magnetosphere in the process. As a result, the behavior of the magnetosphere changes with variations in the interplanetary magnetic field and solar activity. Understanding the behavior of the magnetosphere is crucial for accurate predictions of space weather storms and protecting earth-based systems such as satellites, airlines, and power grids. The purpose of this project is to study the properties of the solar wind at specific stages in the 11-year solar cycle in order to simulate changes in the magnetosphere resulting from fluctuating solar activity. By modeling the magnetosphere, we can better understand our planets relationship with the sun as well as predict times of vulnerability to space weather.
Student Research Symposium. Project for Dr. Nykyriâs Space Weather (PS214) class.
Keywords: Magnetosphere, solar wind, simulation, modeling, interplanetary magnetic field, solar cycl
The Importance of Brain Banks for Molecular Neuropathological Research: The New South Wales Tissue Resource Centre Experience
New developments in molecular neuropathology have evoked increased demands for postmortem human brain tissue. The New South Wales Tissue Resource Centre (TRC) at The University of Sydney has grown from a small tissue collection into one of the leading international brain banking facilities, which operates with best practice and quality control protocols. The focus of this tissue collection is on schizophrenia and allied disorders, alcohol use disorders and controls. This review highlights changes in TRC operational procedures dictated by modern neuroscience, and provides examples of applications of modern molecular techniques to study the neuropathogenesis of many different brain disorders
Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study
Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world.
Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231.
Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05â2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001).
Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication
An Investigation Into the Relationship Between Lightning and GNSS Signal Disturbances in Daytona Beach, FL
Ionospheric scintillations can affect the Global Navigation Satellite Systemâs (GNSS) signals by disrupting the radio waves as they travel through the upper atmosphere. Space weather events are known to cause variations in the total electron content (TEC) of the ionosphere in high and low latitude regions, leading to these scintillations. However, the extent to which these scintillations occur in the mid-latitude region and their causes is under-examined. The goal of our research is to better analyze disruptions to ground-based receivers and GNSS signals by determining whether lightning strikes cause ionospheric scintillations and other interferences with GNSS satellites. As the lightning capital of the world, Florida is an ideal place to record a large data set of thunderstorms. Using high rate (50Hz) multi constellation GNSS receivers at Daytona Beach, FL on the Embry-Riddle University campus, we parse and filter the scintillation data to obtain signal phase and amplitude fluctuations that are coincident with thunderstorms. For finding spatial correlation we compare ionospheric pierce points (IPP) of the satellites on which we observed fluctuations with a data set of lightning strikes and their coordinates, type, and peak current. After analysis of approx. 185+ hours of thunderstorm data, we have observed power drops which are most likely interference at the receiver end associated with lightning. We observed drops in the power of GNSS data on almost all visible satellite signals during the thunderstorms and we are further investigating anomalous peaks/ drops in power which are not visible on all available satellites--possibly related to more localized events. If a direct relationship is found between thunderstorms and scintillation, it would provide a better understanding of tropospheric effects on the ionosphere, besides assisting in improving the reliability of GPS receivers