Oscillation and nonoscillation of functional differential equations

A qualitative approach is usually concerned with the behavior of solutions of a given differential equation and usually does not seek specific explicit solutions;This dissertation is the analysis of nonoscillation of even order delay differential equations, and the oscillation of solutions of arbitrary order functional differential equations. This is done mainly in Chapters II and III. Chapter IV deals with the oscillation and nonoscillation of bounded solutions of n-th order delay differential equations. By an oscillatory solution we mean that the solution has infinitely many zeros; otherwise, it is called nonoscillatory solution;The functional differential equations under consideration are:(UNFORMATTED TABLE OR EQUATION FOLLOWS)≤ (A) [r(t)y[superscript]\u27(t)][superscript](2n-1) + [sigma][subscript]spi=1k P[subscript]i(t) F[subscript]i[y[subscript][tau](t),y[subscript]sp[sigma][subscript]1\u27(t),...,y[subscript]sp[sigma][subscript]2n-1(2n-1)&(t)] & = f(t), n ≥ 1& x[superscript](n)(t) + [sigma] [sigma][subscript]spi=1m P[subscript]i(t) x[g[subscript]i(t)] + [delta] q(t) x[h(t)]& = f(t), n ≥ 3& (B) L[subscript]n x(t) + (-1)[superscript]n-1 [sigma][subscript]spi=1m a[subscript]i(t)f[x(g[subscript]i(t)]& = b(t), n ≥ 1& (C) (TABLE/EQUATION ENDS);Equation (A) is considered in Chapter II, where we find sufficient conditions for which all solutions of equation (A) are nonnegative. Equation (B) is studied in Chapter III for the cases: [delta] = 0, [sigma] = 0 and [sigma] = [delta] = ±1 i.e., delay arguments, advanced arguments, and mixed type arguments, respectively. Finally, equation (C) is studied in Chapter IV. Sufficient conditions are found to force all bounded solutions to be oscillatory, and sufficient conditions are also found for which every bounded solution of equation (C) tends to zero as t → [infinity]

Optoacoustic frequency stabilization of a carbon dioxide laser

In this thesis a study has been made of the design, construction and, in particular, frequency stabilization of a d.c. excited carbon dioxide laser. The outline of the theory of the carbon dioxide laser is presented as a prelude to a detailed study of optogalvanic and optoacoustic effects. Experimental investigations have been made of both of these phenomena, and the results used for frequency stabilization of a conventional large tube diameter flowing gas type of carbon dioxide laser. A special feature of the work is intra-cavity optoacoustic detection of laser power by carbon dioxide gas absorption within the laser tube itself but outside the plasma region, for a new method of frequency stabilization. It is shown experimentally that this novel method is superior to the well established optogalvanic technique of frequency stabilization, in terms of signal to noise ratio and short response time. Extension of the intra-cavity optoacoustic method to both d.c. and r.f. excited waveguide lasers is discussed

Photoacoustic detection in the Michelson interferometer cavity

For the first time, we report photoacoustic (PA) signal detection in a cell placed within the Michelson interferometer cavity in an attempt to relate photoacoustic effect to the Michelson fringe shift as a result of changes in the cell. Both detection schemes were investigated using IR absorption and their sensitivities compared. Signals related to Michelson interferometer fringe and PA effect have shown good correlations with each other using different samples including some essential oils and their corresponding plant part from which the essential oil is usually obtained. Results were encouraging and will open the door widely to use the combined Michelson interferometer- photoacoustic spectroscopy (PAS) in trace gas detection for different applications

Detection of Vapour Emissions from Star Anise Seeds and Mint Leaves using the CO2 Laser Photoacoustic Technique

The aim of this work was to establish the feasibility of the detection of the vapours of the star anise and mint essential oils emitted from the uncrushed seeds of star anise (Illicium verum H.) and from the leaves of Japanese mint (Mentha arvensis L.) respectively using a heat pipe type of photoacoustic cell in conjunction with a line tunable waveguide CO2 laser. Infrared photoacoustic stick spectra were obtained with excellent reproducibility and a high signal-to-noise ratio for the vapour emissions in one atmosphere of nitrogen gas over a temperature range from 20°C up to 180°C in the case of anise seeds and from 20°C to 100°C for mint leaves. Significant differences found between the photoacoustic spectra from the vapour emission of seeds and leaves when compared with commercial samples of the related essential oils are discussed.The financial support for travel from the British Council, East Jerusalem to (DL, MA-T) and that from Royal Society of London to (MA-T, KH) are gratefully acknowledged

The role of information technology in raising the efficiency of Amman stock exchange mediated by the behavior of the stock prices

The study aimed to explore the role of information technology in raising the efficiency of the Amman Stock Exchange, mediated by the behavior of the stock prices. The study chose a sample consisting of 24 companies that are listed on the Amman Stock Exchange. The study used the average of the abnormal return of the stocks gained by companies through information technology applications. The study carried out a multiple regression analysis to explore the degree to which the independent variable affected the dependent one. The study results found that the abnormal return of the stocks gained by companies through information technology applications is low. The study also found that there is a significant relationship between using IT applications and the efficiency of the Amman Stock Exchange, mediated by the behavior of the stock prices. Therefore, the study recommends expanding the scope of using IT in emerging stock markets, including the Amman Stock Exchange, with the aim of raising the operational efficiency of such markets

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

Global burden of chronic respiratory diseases and risk factors, 1990–2019: an update from the Global Burden of Disease Study 2019

Background: Updated data on chronic respiratory diseases (CRDs) are vital in their prevention, control, and treatment in the path to achieving the third UN Sustainable Development Goals (SDGs), a one-third reduction in premature mortality from non-communicable diseases by 2030. We provided global, regional, and national estimates of the burden of CRDs and their attributable risks from 1990 to 2019. Methods: Using data from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019, we estimated mortality, years lived with disability, years of life lost, disability-adjusted life years (DALYs), prevalence, and incidence of CRDs, i.e. chronic obstructive pulmonary disease (COPD), asthma, pneumoconiosis, interstitial lung disease and pulmonary sarcoidosis, and other CRDs, from 1990 to 2019 by sex, age, region, and Socio-demographic Index (SDI) in 204 countries and territories. Deaths and DALYs from CRDs attributable to each risk factor were estimated according to relative risks, risk exposure, and the theoretical minimum risk exposure level input. Findings: In 2019, CRDs were the third leading cause of death responsible for 4.0 million deaths (95% uncertainty interval 3.6–4.3) with a prevalence of 454.6 million cases (417.4–499.1) globally. While the total deaths and prevalence of CRDs have increased by 28.5% and 39.8%, the age-standardised rates have dropped by 41.7% and 16.9% from 1990 to 2019, respectively. COPD, with 212.3 million (200.4–225.1) prevalent cases, was the primary cause of deaths from CRDs, accounting for 3.3 million (2.9–3.6) deaths. With 262.4 million (224.1–309.5) prevalent cases, asthma had the highest prevalence among CRDs. The age-standardised rates of all burden measures of COPD, asthma, and pneumoconiosis have reduced globally from 1990 to 2019. Nevertheless, the age-standardised rates of incidence and prevalence of interstitial lung disease and pulmonary sarcoidosis have increased throughout this period. Low- and low-middle SDI countries had the highest age-standardised death and DALYs rates while the high SDI quintile had the highest prevalence rate of CRDs. The highest deaths and DALYs from CRDs were attributed to smoking globally, followed by air pollution and occupational risks. Non-optimal temperature and high body-mass index were additional risk factors for COPD and asthma, respectively. Interpretation: Albeit the age-standardised prevalence, death, and DALYs rates of CRDs have decreased, they still cause a substantial burden and deaths worldwide. The high death and DALYs rates in low and low-middle SDI countries highlights the urgent need for improved preventive, diagnostic, and therapeutic measures. Global strategies for tobacco control, enhancing air quality, reducing occupational hazards, and fostering clean cooking fuels are crucial steps in reducing the burden of CRDs, especially in low- and lower-middle income countries

Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely

Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

Background Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide.Methods A multimethods analysis was performed as part of the GlobalSurg 3 study-a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital.Findings Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3.85 [95% CI 2.58-5.75]; p<0.0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63.0% vs 82.7%; OR 0.35 [0.23-0.53]; p<0.0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer.Interpretation Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised