1,592 research outputs found
Trade and Geography in the Economic Origins of Islam: Theory and Evidence
This research examines the economic origins of Islam and uncovers two empirical regularities. First, Muslim countries, virtual countries and ethnic groups, exhibit highly unequal regional agricultural endowments. Second, Muslim adherence is systematically larger along the pre-Islamic trade routes in the Old World. The theory argues that this particular type of geography (i) determined the economic aspects of the religious doctrine upon which Islam was formed, and (ii) shaped its subsequent economic performance. It suggests that the unequal distribution of land endowments conferred differential gains from trade across regions, fostering predatory behavior from the poorly endowed ones. In such an environment it was mutually bene.cial to institute a system of income redistribution. However, a higher propensity to save by the rich would exacerbate wealth inequality rendering redistribution unsustainable, leading to the demise of the Islamic unity. Consequently, income inequality had to remain within limits for Islam to persist. This was instituted via restrictions on physical capital accumulation. Such rules rendered the investments on public goods, through religious endowments, increasingly attractive. As a result, capital accumulation remained low and wealth inequality bounded. Geography and trade shaped the set of economically relevant religious principles of Islam affecting its economic trajectory in the preindustrial world.
On The Buckling of Fiber-Bundle Type Beams
Euler was the first who studied for engineering applications important problem of buckling arising in a simple, monolithic beam loaded axially by a concentrated load. As it has been shown from two solutions of the problem due to Timosenko theory, the elastic foundation increases the critical buckling load of the beam. Starting from the previous classical results, a mechanism to enhance the buckling strength of a cantilevered beam is investigated. In the place of a single, one-element, monolithic cross-section, the use of a bundle of more than one, similar or not, single cross-sections, placed with parallel axes, and staying in free (unilateral) contact along their adjacent boundaries, is proposed
Evolution of antimicrobial prophylaxis in cardiovascular surgery
Objective: To examine the optimal duration of antibiotic prophylaxis in major cardiovascular surgery. Methods: In the past 15 years, four prospective randomized, controlled studies, conducted by the same group of authors, compared seven prophylactic antimicrobial regimens in 2970 patients undergoing major cardiovascular surgery. In 1980/81, a 4-day cefazolin (CFZ) prophylaxis was compared with a 2-day cefuroxime (CFX) administration (n=566). In 1982/83, a 2-day CFX prophylaxis was compared with a two shot ceftriaxone (CRO) prophylaxis (n=512). In 1984/87, a 1-day CFZ prophylaxis was compared with a single shot prophylaxis of CRO (n=883). In 1994/1995, a 4 day combination of amoxicillin (AM) and netilmicin (NET) prophylaxis was compared with a single shot prophylaxis of CFX (n=1009). Results: Total infection rate varied between 4.5 and 5.7%, despite different antimicrobial regimen used and their varying duration. Wound infection rate was 1.1% (range 0.4-2.5%), sepsis rate was 0.8% (range 0.4-1.6%), pneumonia rate 2% (0.7-2.9%), urinary tract infection rate 0.4% (range 0-1.4%), and central venous catheter-related infection rate was 0.4% (0-1%). The 30-day mortality rate was 1.3% (range 0.4-2%). All these differences were not statistically significant. Conclusions: A low infection rate (range 4.5-5.7%) occurred despite changes in duration of various prophylactic antibiotic regimen with cephalosporins of first, second or third generation. As a single shot prophylaxis could nowadays successfully be used in cardiovascular surgery, no postoperative antibiotics should be used, unless an intraoperative or a postoperative infection is documented or in presence of major perioperative complication
Potential for Liquefaction Due to Construction Blasting
A method based on laboratory cyclic triaxial and torsional tests of undisturbed soil samples has been developed to predict the potential for liquefaction due to buried charges, such as those used in construction blasting. The results of a test blasting program conducted at a construction site are presented. The case history yielded data on particle velocities and blast induced porewater pressure changes
Passive Control of Bridges
In the design of bridges with large spans, the significant values of the moments at the main deck-structure require very heavy members, either in the case of a beam or a truss deck-structure. In order to minimize the influence of bending moments, several applications of passive control of displacements using cable nets are herein proposed. The base for all the proposed systems is the cables supported beam nets with additional prestressing control on support cables to optimize the structural behavior of the system. The passive control design problem leads to an optimal control problem for structures governed by variational inequalities. In this presentation several bridge systems are proposed and studied as applications of this method
Worldwide research productivity in critical care medicine
INTRODUCTION: The number of publications and the impact factor of journals are accepted estimates of the quantity and quality of research productivity. The objective of the present study was to assess the worldwide scientific contribution in the field of critical care medicine. METHOD: All research studies published between 1995 and 2003 in medical journals that were listed in the 2003 Science Citation Index (SCI(®)) of Journal Citation Reports under the subheading 'critical care' and also indexed in the PubMed database were reviewed in order to identify their geographical origin. RESULTS: Of 22,976 critical care publications in 14 medical journals, 17,630 originated from Western Europe and the USA (76.7%). A significant increase in the number of publications originated from Western European countries during the last 5 years of the study period was noticed. Scientific publications in critical care medicine increased significantly (25%) from 1995 to 2003, which was accompanied by an increase in the impact factor of the corresponding journals (47.4%). Canada and Japan had the better performance, based on the impact factor of journals. CONCLUSION: Significant scientific progress in critical care research took place during the period of study (1995–2003). Leaders of research productivity (in terms of absolute numbers) were Western Europe and the USA. Publications originating from Western European countries increased significantly in quantity and quality over the study period. Articles originating from Canada, Japan, and the USA had the highest mean impact factor.. Canada was the leader in productivity when adjustments for gross domestic product and population were made
Change in anaesthesia practice and postoperative sedation shortens ICU and hospital length of stay following coronary artery bypass surgery
AbstractWe randomized prospectively 144 patients, undergoing elective coronary artery bypass surgery, to either early or to routine extubation [mechanical ventilatory support for 4–7 h (Group A), or 8–14 h (Group B)]. Anaesthesia was modified for both groups. The groups were well matched in terms of sex, age, NYHA class, preoperative left ventricular ejection fraction, bypass time and aortic cross-clamp time, number of grafts used, and blood units transfused. All patients had normal preoperative respiratory, renal, hepatic and cerebral functions. Mechanical ventilatory support (mean ± sd) was 6·3 ± 0·7 h for Group A and 11·6 ± 1·3 h for Group B. Mean ICU stay was 17 ± 1·3 h for Group A and 22 ± 1·2 h for Group B, while the mean hospital stay was 7·3 ± 0·8 days and 8·4 ± 0·9, respectively. There were no statistically significant differences in the frequency of all postoperative complications among the two groups. There were no reintubation, readmission to the ICU or death in either group. We concluded that change in anaesthesia practice and early postoperative sedation in patients undergoing elective coronary artery bypass graft (CABG) surgery resulted in earlier tracheal extubation, shorter ICU and hospital length of stay without organ dysfunction or postoperative complications. Early extubation was only possible due to the modification of anaesthesia and ICU sedation regime
Giant congenital left main coronary artery fistula to the superior vena cava in an adult patient with coronary artery disease
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