Synthetic aperture radar target simulator

A simulator for simulating the radar return, or echo, from a target seen by a SAR antenna mounted on a platform moving with respect to the target is described. It includes a first-in first-out memory which has digital information clocked in at a rate related to the frequency of a transmitted radar signal and digital information clocked out with a fixed delay defining range between the SAR and the simulated target, and at a rate related to the frequency of the return signal. An RF input signal having a frequency similar to that utilized by a synthetic aperture array radar is mixed with a local oscillator signal to provide a first baseband signal having a frequency considerably lower than that of the RF input signal

Undescended retropharyngeal parathyroid adenoma with adjacent thymic tissue in a 13-year-old boy with primary hyperparathyroidism.

We describe a rare presentation of a symptomatic parathyroid adenoma located in an ectopic retropharyngeal position in a 13-year-old boy. Preoperative CT scan and MRI demonstrated the ectopic location of the parathyroid adenoma. The patient underwent successful parathyroidectomy with cure of his hyperparathyroidism. On pathologic exam, the specimen was made up of a parathyroid adenoma and adjacent thymic tissue, indicating that it was likely an undescended lower parathyroid gland arising from the third pharyngeal pouch. Ectopic retropharyngeal parathyroid adenomas are very rare and to our knowledge, none have been previously described in adolescents

Outcomes analysis of new entrant screening for active tuberculosis in Heathrow and Gatwick airports, United Kingdom 2009/2010

BACKGROUND: In 2012, the United Kingdom (UK) Government announced that the new entrant screening for active tuberculosis (TB) in Heathrow and Gatwick airports would end. Our study objective was to estimate screening yield and diagnostic accuracy, and identify those at risk of active TB after entry. METHODS: We designed a retrospective cohort study and linked new entrants screened from June 2009 to September 2010 through probabilistic matching with UK Enhanced TB Surveillance (ETS) data (June 2009 to December 2010). Yield was the proportion of cases reported to ETS within three months of airport screening in the screened population. To estimate screening diagnostic accuracy we assessed sensitivity, specificity, positive and negative predictive values. Through Poisson regression we identified groups at increased risk of TB diagnosis after entry. RESULTS: We identified 200,199 screened entrants, of these 59 had suspected TB at screening and were reported within 3 months to ETS (yield = 0.03 %). Sensitivity was 26 %; specificity was 99.7 %; positive predictive value was 13.2 %; negative predictive value was 99.9 %. Overall, 350 entrants were reported in ETS. Persons from countries with annual TB incidence higher than 150 cases per 100,000 population and refugees and asylum seekers were at increased risk of TB diagnosis after entry (population attributable risk 77 and 3 % respectively). CONCLUSION: Airport screening has very low screening yields, sensitivity and positive predictive value. New entrants coming from countries with annual TB incidence higher than 150 per 100,000 population, refugees and asylum seekers should be prioritised at pre- or post-entry screening

Improving Surgical Care in Low- and Middle-Income Countries: A Pivotal Role for the World Health Organization

In response to increasing evidence that surgical conditions are an important global public health problem, and data suggesting that essential surgical services can be delivered in a cost-effective manner in low- and middle-income countries, the World Health Organization (WHO) has expanded its interest in surgical care. In 2004, WHO established a Clinical Procedures Unit within the Department of Essential Health Technologies. This unit has developed the Emergency and Essential Surgical Project (EESC), which includes a basic surgical training program based on the “Integrated Management of Emergency and Essential Surgical Care” Toolkit and the textbook “Surgery at the District Hospital.” To promote the importance of emergency and essential surgical care, a Global Initiative for Emergency and Essential Care was launched in 2005. In what maybe the most important development, surgical care is included in WHO’s new comprehensive primary health care plan. Given these rapid developments, surgical care at WHO may be approaching a critical “tipping point.” Lobbying for a World Health Assembly resolution on emergency and essential surgical care, and developing “structured collaborations” between WHO and various stakeholders are potential ways to ensure that the global surgery agenda continues to move forward

Key Concepts for Estimating the Burden of Surgical Conditions and the Unmet Need for Surgical Care

Background: Surgical care is emerging as a crucial issue in global public health. Methodology is needed to assess the impact of surgical care from a public health perspective. Methods: A consensus opinion of a group of surgeons, anesthesiologists, and public health experts was established regarding the methodology for estimating the burden of surgical conditions and the unmet need for surgical care. Results: For purposes of analysis, we define surgical conditions as any disease state requiring the expertise of a surgically trained provider. Abnormalities resulting from a surgical condition or its treatment are termed surgical sequelae. Surgical care is defined as any measure that reduces the rates of physical disability or premature death associated with a surgical condition. To measure the burden of surgical conditions and unmet need for surgical care we propose using cumulative disability-adjusted life-year (DALY) curves generated from age-specific population-based data. This conceptual framework is based on the premise that surgically associated disability and death is determined by the incidence of surgical conditions and the quantity and quality of surgical care. The burden of surgical conditions is defined as the total disability and premature deaths that would occur in a population should there be no surgical care; the unmet need for surgical care is defined as the potentially treatable disability and premature deaths due to surgical conditions. Burden of surgical conditions should be expressed as DALYs and unmet need as potential DALYs avertable. Conclusions: Methodology is described for estimating the burden of surgical conditions and unmet need for surgical care. Using this approach it will be feasible to estimate the global burden of surgical conditions and help clarify where surgery fits among other global health priorities. These methods need to be validated using population-based data

Timing and cost of scaling up surgical services in low-income and middle-income countries from 2012 to 2030 : a modelling study

Background: Given the large burden of surgical conditions and the crosscutting nature of surgery, scale-up of basic surgical services is crucial to health-system strengthening. The Lancet Commission on Global Surgery proposed that, to meet populations' needs, countries should achieve 5000 major operations per 100 000 population per year. We modelled the possible scale-up of surgical services in 88 low-income and middle-income countries with a population greater than 1 million from 2012 to 2030 at various rates and quantified the associated costs. Methods: Major surgery includes any intervention within an operating room involving tissue manipulation and anaesthesia. We used estimates for the number of major operations achieved per country annually and the number of operating rooms per region, and data from Mongolia and Mexico for trends in the number of operations. Unit costs included a cost per operation, proxied by caesarean section cost estimates; hospital construction data were used to estimate cost per operating room construction. We determined the year by which each country would achieve the Commission's target. We modelled three scenarios for the scale-up rate: actual rates (5·1% per year) and two "aspirational" rates, the rates achieved by Mongolia (8·9% annual) and Mexico (22·5% annual). We subsequently estimated the associated costs. Findings: About half of the 88 countries would achieve the target by 2030 at actual rates of improvements, with up to two-thirds if the rate were increased to Mongolian rates. We estimate the total costs of achieving scale-up at US$300-420 billion (95% UI 190-600 billion) over 2012-30, which represents 4-8% of total annual health expenditures among low-income and lower middle-income countries and 1% among upper middle-income countries. Interpretation: Scale-up of surgical services will not reach the target of 5000 operations per 100 000 by 2030 in about half of low-income and middle-income countries without increased funding, which countries and the international community must seek to achieve expansion of quality surgical services

Positive effects of intercrop yields in farms from across Europe depend on rainfall, crop composition, and management

\ua9 The Author(s) 2024.Modern “intensive” agriculture drives the biodiversity-climate crisis but is also central to global food security. Future farming needs management approaches that maintain (or even enhance) food production while reducing negative climate and biodiversity impacts. Intercrops could provide part of the solution, increasing biodiversity and boosting production with fewer inputs. However, barriers remain to their wide-scale uptake, in particular tailoring intercrops to local equipment, management practice, and environment. We analyze data from multiple trials of cereal-legume intercrops conducted on farms across Europe between 2018 and 2021. Our study is the first attempt, to our knowledge, to quantify the yield benefits of cereal-legume intercropping undertaken at commercially relevant scales for farms across Europe. We used crop performance ratio (CPR)—the ratio of the observed intercrop yield compared to the expected yield based on monoculture yields—as our metric of intercrop performance. Using CPR, we found a roughly 30% yield gain across all sites. However, CPR was modulated by a number of factors. CPR was not strongly affected by management except for the negative effects of direct drilling and the positive effects of organic fertilizer addition. CPR also depended on intercrop composition (number and identity of components), background yields (being highest where yields were lower), and rainfall (being higher with higher rainfall). Our findings allow us to reduce uncertainty about how intercrops will perform in realistic local farm conditions, give guidance for tailoring intercrops to local farming conditions, and provide key goals for further work to integrate intercrops into sustainable farming systems

Comparative Cost-Effectiveness Analysis of Two MSF Surgical Trauma Centers

INTRODUCTION: There is a dearth of data on cost-effectiveness of surgical care in resource-poor countries. Doctors Without Borders (Médecins Sans Frontières; MSF) is a nongovernmental organization (NGO) involved in the many facets of health care for underserved populations, including surgical care. METHODS: A cost-effectiveness analysis (CEA) was attempted at two of their surgical trauma hospitals: Teme Hospital in Nigeria and La Trinité Hospital in Haiti. CONCLUSION: At $172 and$223 per Disability-Adjusted Life-Year (DALY) averted, respectively, they are in line with other reported CEAs for surgical and nonsurgical activities in similar contexts

Essential Surgery at the District Hospital: A Retrospective Descriptive Analysis in Three African Countries

In the first of two papers investigating surgical provision in eight district hospitals in Saharan African countries, Margaret Kruk and colleagues find low levels of surgical care provision suggesting unmet need for surgical services

Global access to surgical care: a modelling study

Background More than 2 billion people are unable to receive surgical care based on operating theatre density alone. The vision of the Lancet Commission on Global Surgery is universal access to safe, aff ordable surgical and anaesthesia care when needed. We aimed to estimate the number of individuals worldwide without access to surgical services as defi ned by the Commission’s vision. Methods We modelled access to surgical services in 196 countries with respect to four dimensions: timeliness, surgical capacity, safety, and aff ordability. We built a chance tree for each country to model the probability of surgical access with respect to each dimension, and from this we constructed a statistical model to estimate the proportion of the population in each country that does not have access to surgical services. We accounted for uncertainty with oneway sensitivity analyses, multiple imputation for missing data, and probabilistic sensitivity analysis. Findings At least 4·8 billion people (95% posterior credible interval 4·6–5·0 [67%, 64–70]) of the world’s population do not have access to surgery. The proportion of the population without access varied widely when stratifi ed by epidemiological region: greater than 95% of the population in south Asia and central, eastern, and western sub- Saharan Africa do not have access to care, whereas less than 5% of the population in Australasia, high-income North America, and western Europe lack access. Interpretation Most of the world’s population does not have access to surgical care, and access is inequitably distributed. The near absence of access in many low-income and middle-income countries represents a crisis, and as the global health community continues to support the advancement of universal health coverage, increasing access to surgical services will play a central role in ensuring health care for all