Different Types Of Operations Research Articles

Building surgical research capacity in Mozambique.

Background: Surgically treatable conditions are increasingly recognized as important public health problems in low- and middle-income countries.1–3 In Mozambique, the majority of surgery in rural areas is performed by “técnicos de cirurgia”—nonphysician surgeons trained locally. To better define rural surgical needs in Mozambique and to improve surgical care, the Universidade Eduardo Mondlane (UEM) formed a research partnership with the University of California, San Diego (UCSD) in 2010. Funded by a Medical Education Partnership Initiative linked award, the specific aims of the of the project are to identify the best strategies for building emergency and essential surgical capacity in rural areas of Mozambique and to increase capacity for surgical research at UEM and its allied institutions. Intervention: During the first 36 months of the UEM-UCSD surgical partnership, a number of research projects have been initiated. These have focused on defining the unmet need for surgical care in rural communities surrounding hospitals; types of surgical procedures performed by the nonphysician surgeons; clinical epidemiology of pediatric trauma as one of the unmet surgical needs; and risk-adjusted outcomes of surgical patients. These projects have been used as the platform to increase capacity for surgical research among local personnel. Outcomes: A community-based survey of 6,104 people living near three primary referral hospitals in rural Mozambique, conducted June 2012 to June 2013, showed that 36% of the respondents had current or historical surgical disease. Review of inpatient records revealed that about 60% of hospital admissions were for treatment of surgical conditions. Compared with patients admitted for nonsurgical problems, surgical patients had longer hospital stays and a greater number of total hospital days. In the rural hospitals studied, nonphysician surgeons performed more than 95% of the surgical procedures and 52 different types of operations, of which 73% were surgical emergencies. The three most common procedures were cesarean section (62%), herniorrhaphy (9%), and exploratory laparotomy (4%). Ten procedures accounted for 80% of the surgical volume. Seventy percent of the pediatric surgical admissions were for injuries, with falls (44%), burns (23%), and road traffic accidents (18%) being the most common. Calculation of risk-adjusted operative outcomes is currently under way. Comment: Our preliminary findings suggest that surgical conditions, especially injuries and obstetrical problems, are common in rural areas of Mozambique and place a significant burden on the health system. While typical of the surgical epidemiology observed in other low- and middle income countries, it emphasizes the important role surgical care has in treating maternal and child health problems. Given the high prevalence of untreated surgical conditions identified in our community-based survey, there is a critical need to better understand which factors limit delivery of surgical care and how surgery fits into the larger health system. Some of the greatest challenges exist in the supply, training, and distribution of human resources for surgical care. Educating and training surgeons is time consuming and expensive, and once qualified, many are reluctant to serve in rural first-level hospitals where the needs are often the greatest. The técnicos de cirurgia model used in Mozambique can provide important information on how best to address the critical need for surgeons in other countries in Sub-Saharan Africa.

Gentamicin/collagen sponge use may reduce the risk of surgical site infections for patients undergoing cardiac operations: a meta-analysis.

A meta-analysis of all published randomized controlled trials of the effectiveness of gentamicin/collagen sponges for preventing surgical site infections (SSIs). Despite routine use of systemic prophylactic antimicrobial agents, SSIs continue to be associated with substantial morbidity. RESULTS conflict of studies of the efficacy of gentamicin/collagen sponges for preventing SSIs. However, many of these studies have assessed sponge use in only a single specific type of operation. The general effect of sponge use among different types of operations has not been previously assessed. The PubMed and Cumulative Index to Nursing and Allied Health Literature (CINAHL) databases were searched for articles appearing from 1990 through January 2012 that were related to gentamicin/collagen sponge use and SSIs. Summary estimates were obtained through a random effects model. After reviewing 714 article abstracts and reviewing 22 articles in detail, we pooled the odds ratios (OR) for 13 independent study populations (cardiac, n=4; colorectal, n=4; pilonidal sinus, n=2; hernia, n=2; gastrointestinal, n=1) in which the association between prophylactic use of gentamicin/collagen sponges and SSIs was assessed. Pooling of the results of all studies included in the review in a random effects model showed a significant protective effect of prophylactic use of gentamicin/collagen sponges against SSI (pooled OR: 0.66; 95% confidence interval [CI]: 0.45, 0.97; n=13). However, when the data were stratified by type of operation, a significant protective effect was observed in cardiac procedures (pooled OR: 0.59; 95% CI: 0.37, 0.96; n=4) but not in colorectal procedures (pooled OR: 0.74; 95% CI: 0.29-1.92; n=4). Use of gentamicin/collagen sponges was associated with a reduced risk of SSI following cardiac operations but not following colorectal procedures.

Estructura y función del intestino delgado post-vagotomía y antrectomía

El propósito de este trabajo es estudiar las posibles alteraciones morfológicas y funcionales del intestino delgado en pacientes sometidos a Antrectomía y Vagotomía por úlcera duodenal. La literatura médica pertinente es escasa y esto nos han llevado a realizar un estudio completo en pacientes internados en el Servicio de Gastroenterología del Hospital Obrero de Lima. Hay estudios acerca de la biopsia intestinal en pacientes ulcerosos que han sido sometidos a diferentes tipos de operación: gastrectomía, vagotomía y piloroplastía, pero ninguno en enfermos con antrectomía y vagotomía troncular. Es Esta circunstancia la que le da originalidad al presente trabajo, a lo que se suma el estudio de Ia capacidad digestiva del paciente y otros datos relacionados con un control alejado post-operatorio. No es nuestra intención juzgar las ventajas y desventajas de determinado tipo de operación; sólo nos hemos concretado a la búsqueda de alteraciones intestinales. Con este objeto se han estudiado 15 pacientes del Hospital Obrero de Lima, contando con el auspicio de la Facultad de Medicina de San Fernando y de la Dirección del Hospital.

Distributed Subgradient-Based Coordination of Multiple Renewable Generators in a Microgrid

For a microgrid with high renewable energy penetration to work autonomously, it must maintain its own supply-demand balance of active power. Maximum peak power tracking algorithms, which emphasize high renewable energy utilization, may cause a supply-demand imbalance when the available renewable generation is more than demanded, especially for autonomous microgrids. Currently, droop control is one of the most popular decentralized methods for sharing active and reactive loads among the distributed generators. However, conventional droop control methods suffer from slow and oscillating dynamic response and steady state deviations. To overcome these problems, this paper proposes a distributed subgradient-based solution to coordinate the operations of different types of distributed renewable generators in a microgrid. By controlling the utilization levels of renewable generators, the supply-demand balance can be well maintained and the system dynamic performance can be significantly improved. Simulation results demonstrate the effectiveness of the proposed control solution.

Competencies among virtual reference library and information science professionals: An insight

Reference services play a very important role in satisfying the information needs of the users. Essence of reference services is to provide personal assistance to the users when they face any kind of problem while exploiting the services provided by the library and information centers. With the advancement of information and communication technology libraries have introduced different technologies for performing different types of operations. Reference services have also got a technology touch in the digital information environment in order to fulfill the changing information needs of their patrons through the provision of virtual reference services. Providing effective and efficient virtual reference services depends upon the competencies and capabilities of the professionals who are engaged in providing these services to the library patrons. Present paper highlights the concept of virtual reference services in detail along with the competencies essential for providing these virtual reference services to the users.

Gauss–Manin connections for p-adic families of nearly overconvergent modular forms

We interpolate the Gauss–Manin connection in p-adic families of nearly overconvergent modular forms. This gives a family of Maass–Shimura type differential operators from the space of nearly overconvergent modular forms of type r to the space of nearly overconvergent modular forms of type r+1 with p-adic weight shifted by 2. Our construction is purely geometric, using Andreatta–Iovita–Stevens and Pilloni’s geometric construction of eigencurves, and should thus generalize to higher rank groups.

Specialization and the Current Practices of General Surgeons

The impact of specialization on the practice of general surgery has not been characterized. Our goal was to assess general surgeons' operative practices to inform surgical education and workforce planning. We examined the practices of general surgeons identified in the 2008 State Inpatient and Ambulatory Surgery Databases of the Healthcare Cost and Utilization Project for 3 US states. Operations were identified using ICD-9 and CPT codes linked to encrypted physician identifiers. For each surgeon, total operative volume and percentage of practice that made up their most common operation were calculated. Correlation was measured between general surgeons' case volume and the number of other specialists in a health service area. There were 1,075 general surgeons who performed 240,510 operations in 2008. The mean operative volume for each surgeon was 224 annual procedures. General surgeons performed an average of 23 different types of operations. For the majority of general surgeons, their most common procedure constituted no more than 30% of total practice. The most common operations, ranked by the frequency they appeared as general surgeons' top procedure, included cholecystectomy, colonoscopy, endoscopy, and skin excision. The proportion of general surgery practice composed of endoscopic procedures inversely correlated with the number of gastroenterologists in the health service area (rho = -0.50; p = 0.005). Despite trends toward specialization, the current practices of general surgeons remain heterogeneous. This indicates a continued demand for broad-based surgical education to allow future surgeons to tailor their practices to their environment.

Bariatric Surgery and the Mechanism of Diabetes Remission: Are We Getting There?

The worldwide obesity epidemic and its accompanying pathologies of type 2 diabetes mellitus and cardiovascular disease have underscored the need for effective weight-lossstrategies(1).Despiteintensiveeffortsandnumerousemergingfindings,reliableandsafepharmacological approaches that are able to effectively decrease body weight and maintain this reduction in the long run remain elusive.Bariatricsurgeryremainstheonlystrategyproven to achieve and sustain significant weight loss in patients with more severe degrees of obesity (2, 3). These procedures not only markedly reduce body weight but also radically improve diabetes control or lead to its complete remission in a high percentage of patients. Although clear metabolic improvements are evident in all patients after bariatric surgery, different types of operations appear to vary in the rate of diabetes remission as well as in the timing of metabolic improvements (4). Traditional classification of bariatric operations into restrictiveandmalabsorptiveisnowconsideredinadequateby some leaders in the field (4). Yet it still provides a basis to understand the degree of alteration in gastrointestinal tract anatomy and the mechanism of weight-loss achievement. In restrictive procedures, such as gastric banding, gastric plication,andsleevegastrectomy,decreasedfoodintakeandlongtermweightlossareachievedmainlybyconstrictingstomach size without further modifications of gastrointestinal anatomy.Inthemostmalabsorptiveprocedures(eg,biliopancreatic diversion, Roux-en-Y gastric bypass [RYGB]), stomach size is also partially restricted, and a direct connection of the stomach and the lower part of the small intestine is created. Bypass of a significant portion of the intestine then leads to decreased absorption of nutrients, resulting in weight loss. The rate of diabetes remission after different types of bari

Comparing operations for POP: the importance of standardization of surgical technique

In the past decade, scientific literature regarding surgical treatment for pelvic organ prolapse (POP) has been overwhelmingly about the use of meshes, which has gained credibility after recent publications that report good anatomical outcomes. Nevertheless, results must be considered taking into account the increasing number of reported postoperative complications that have led to some important, cautious reviews and warnings, such as the ones included in the updated US Food and Drug Administration (FDA) communication in 2011 [1]. In this scenario, it is appropriate to review previous studies in order to balance safety and efficacy of surgical therapeutic options. Different types of operations should be carefully reappraised and given their appropriate place in POP management. Special attention should be given to potential conclusion biases inherent to the methodological inconsistencies regarding criteria for population inclusion, cure/failure, and outcomes when various studies addressing a surgical technique are analyzed together. In fact, those points have been raised by some authors [2, 3]. Another aspect, but no less important, is the one related to the lack of standardization of surgical techniques when evaluating the supposed “same operation.” Several types of operations have been described to support apical prolapse [4]. Recently published, the extended Colpopexy and Urinary Reduction Efforts (CARE) trial brought some important issues to the forefront in respect of surgical management of the apical compartment [5]. Despite the unexpected recurrence rate observed over time, abdominal sacrocolpopexy is considered the most durable technique for restoring the prolapsed vaginal apex to a normal anatomic position [4]. However, in the absence of well-controlled and designed studies, definitive conclusion about a gold standard procedure shall be considered merely a matter of speculation. Even if randomized controlled trials and/or meta-analyses are undertaken in the future, questions on appropriate interpretation of results would be subject of criticism and debate due to intraand interobserver variations. In fact, surgeries and surgeons are basically impossible to ideally control for in such circumstances [6]. A good example is the number of technical variations of the McCall culdoplasty and uterosacral ligament suspensions (USLS). Those techniques have undergone diverse technical modifications over the years, including anatomic landmarks, surgical route, and type and exact position of sutures. Physicians should clarify and inform their readers what they mean by “modified McCall” or “high McCall”. Everyone speaks a unique language when attempting to reach a possible common conclusion. The best approach is, of course, another subject of numerous debates. Many surgeons advocate that the procedure performed by laparoscopy seems to have important advantages over the abdominal and vaginal approaches, allowing proper dissection in critical areas, correct identification of uterosacral ligaments and both ureters, as well as placing sutures in a more cranial position, which might positively impact treatment results. As a natural consequence of the lack of standardization among procedures, each being potentially “different” from each other, crucial questions emerge from this discussion: Shall we separately analyze the results obtained from each technique modification, or shall we put them all in the same pocket? In contrast to the time when vaginal mesh kits were perceived as making surgical skill redundant, surgeons must G. Favero Department of Gynecology, Instituto do Câncer do Estado de Sao Paulo, Faculdade de Medicina da Universidade de Sao Paulo, Sao Paulo, Brazil

Preventive Actions to Emerging Threats in Smart Devices Security

Smart devices have become indispensable tools for today's highly mobile workforce. Smart devices can be used for different type of operations, including email service, office stuff and remotely accessing data etc. As these devices deliver productive benefits, they pose new risks like malicious attacks to users. Viruses, worms and Trojans, under whatever category they are classified, can cause anywhere from minor irritation to total system failure. The study revealed that the only type of phone, vulnerable to a virus attack is one that runs an operating system - a Smartphone. There are emerging threats like Smishing, Blue Jacking, Sim Card duplication, Data theft, Mobile Spamming, IMEI change and many more. In this research paper, all such emerging threats have been discussed and solution has been provided to recover from those threats and attacks.

Spectral properties of a Sturm-Liouville type differential operator with a retarding argument

Spectral properties of a differential operator of Sturm-Liouville type are studied in the case of retarding argument with different boundary conditions. The asymptotics of solutions to the corresponding differential equation is studied in the case of a summable potential. An asymptotics of eigenvalues and an asymptotics of eigenfunctions of the differential operator are calculated for each considered case.

On existence of resolvent of a class of singular mixed type differential operators in an unbounded domain

On existence of resolvent of a class of singular mixed type differential operators in an unbounded domain

Effectiveness of FACTS Controllers and HVDC Transmissions for Improving Power System Stability and Increasing Power Transmission Capability

With an increasing demand on energy and the construction of large generation units especially opening of electric power markets, it becomes more and more important to provide stable, secure, controlled and high quality electric power on today’s environment. The regulatory constraints on the expansion of the transmission network has resulted in reduction of stability margins and increased the risks of cascading outages and blackouts. Among many possible solutions to overcome these challenges, FACTS devices and HVDC systems play an important role. These type of devices/systems have shown to be capable in stabilizing transmission systems, resulting in higher transfer capability. FACTS devices and HVDC transmissions have emerged as important solutions to help power systems to increase stability margins. Some of these power electronics-based components have the main function of controlling reactive power (SVC and STATCOM) and some others to control active power (as TCSC and CSC-HVDC transmission). All these devices are also capable of damping electromechanical oscillations. This paper presents a comprehensive review of operation of different types of FACTS controllers in the power system for stability enhancement in term of shunt compensators, series compensators as well as combinations of these two types of compensators. The paper also demonstrates different types of HVDC technology as well as its effectiveness to improve the voltage profile of power system.

Effects of Fibrinogen Concentrate as First-line Therapy during Major Aortic Replacement Surgery

Fibrinogen is suggested to play an important role in managing major bleeding. However, clinical evidence regarding the effect of fibrinogen concentrate (derived from human plasma) on transfusion is limited. The authors assessed whether fibrinogen concentrate can reduce blood transfusion when given as intraoperative, targeted, first-line hemostatic therapy in bleeding patients undergoing aortic replacement surgery. In this single-center, prospective, placebo-controlled, double-blind study, patients aged 18 yr or older undergoing elective thoracic or thoracoabdominal aortic replacement surgery involving cardiopulmonary bypass were randomized to fibrinogen concentrate or placebo, administered intraoperatively. Study medication was given if patients had clinically relevant coagulopathic bleeding immediately after removal from cardiopulmonary bypass and completion of surgical hemostasis. Dosing was individualized using the fibrin-based thromboelastometry test. If bleeding continued, a standardized transfusion protocol was followed. Twenty-nine patients in the fibrinogen concentrate group and 32 patients in the placebo group were eligible for the efficacy analysis. During the first 24 h after the administration of study medication, patients in the fibrinogen concentrate group received fewer allogeneic blood components than did patients in the placebo group (median, 2 vs. 13 U; P < 0.001; primary endpoint). Total avoidance of transfusion was achieved in 13 (45%) of 29 patients in the fibrinogen concentrate group, whereas 32 (100%) of 32 patients in the placebo group received transfusion (P < 0.001). There was no observed safety concern with using fibrinogen concentrate during aortic surgery. Hemostatic therapy with fibrinogen concentrate in patients undergoing aortic surgery significantly reduced the transfusion of allogeneic blood products. Larger multicenter studies are necessary to confirm the role of fibrinogen concentrate in the management of perioperative bleeding in patients with life-threatening coagulopathy.

On the existence of a resolvent of a class of singular mixed type differential operators in an unbounded domain

In the present work the closedness of an operator and the existence of a resolvent for a class of mixed type operators with increasing coefficients in an unbounded domain are proved.

SST-1 Gas feed and Gas Exhaust system

SST-1 tokamak is a long pulse tokamak designed for the plasma operation up to 1000 sec duration. Gas feed system and gas exhaust management will play a very crucial role during plasma discharge. During the different type of operations of tokamak like wall conditioning, diverter operation and neutral beam injection, a large amount of gas will be fed into the vacuum chamber at different locations. Also during plasma operations, the gas will be fed both in continues and pulse mode. Gas feed will be carried out mainly using piezo-electric valves controlled by PXI based data acquisition and control system. Such operations will lead to a huge amount gas exhaust by the main system which requires good exhaust facility to searches, great care should be taken in constructing both. Also initial pumping of cryostat and vacuum vessel of SST-1 will release a large amount of gas. Exhausted gases from SST -1 will be Hydrogen, Nitrogen, Mixture gases or some toxic gases. Dedicated exhaust system controlling the different gases are installed. Special treatment of hazardous/explosive gases is done before releasing to the atmosphere. This paper describes design and implementations of the complete gas feed and exhaust system of SST-1.

From a theoretical model to a predictive simulation model of operator interaction with support systems: designing experiments to build the numerical simulation

In this paper, we will discuss a methodology developed and applied in the European ITERATE project with the objective of designing experiments that will provide data to seed the numerical model of operator behaviour in different surface transport modes: road vehicles, rail transport and ships. The experiments aim to investigate how new technologies support different types of operators in different contexts. A structured approach was adopted. Firstly, an initial selection of the systems to be investigated was made, describing the support they provide for operators. Hypotheses were formulated on the effects of operator parameters on the interaction with the systems. A final selection of systems for the experiments was made, focusing on systems providing support for collision avoidance and speed management. The operator parameters (culture, attitude and personality, experience, driver state (such as fatigue) and the demands of the task) were operationalised and piloted. The next step was the development of scenarios to be implemented in a driving simulator. In the last step, the final experiments were designed and detailed.

Aortic valve sparing operations versus composite graft implantation in acute aortic dissections

ObjectivesType A acute aortic dissection is life threatening disease requiring urgent operation. This type of the operation is often a subject of discussion. In our study we present our first experience with two different types of operations with and without preservation of the aortic valve. Patients and methodsFrom January 2009 to December 2011 fifty six patients underwent the operation due to the acute aortic dissection type A. Ascending aorta was replaced in 32 cases and more complex operation was performed in 24 patients due to the simultaneous severe aortic root damage by dissection (study group). In eleven patients (group A) replacement of aortic valve, aortic root and ascending aorta by composite graft (modified Bentall procedure) was performed and in 13 patients (group B) valve sparing operation (reimplantation according to David) was carried out. ResultsThere were no significant differences between the groups in preoperative variables. The only significant difference was mean duration of hospitalisation; 26.7±13.7 days in group A and 16.4±7.7 days in group B. Hospital mortality was 18.2% (n=2) after Bentall procedure, no patient died in group B. There were no or minimal aortic regurgitation in all patients of group B on echocardiography before discharge. The mean follow-up was 17.6 months (3.6–35.8) in group A, and 23.5 months (7.9–38.9) in group B. During this period of time three patients in group A and one patient in group B died; two of cardiac and two of noncardiac reasons. In group B no patient had aortic regurgitation higher than grade I and all patients were in New York Heart Association functional class I or II. ConclusionAortic valve reimplantation in patients with type A dissection can be performed with excellent early and mid-term results. In the hands of an experienced surgeon it represents a good alternative to the Bentall operation. Its main advantage is the preservation of the native valve without the necessity of anticoagulation therapy.

Recommendations for the Development of a New operational classification System For The Foodservice Industry

The foodservice industry is large and diverse, demanding an adequate system for classifying its many different types of operations. There are many different classification systems in use by industry and researchers. Although many of the current systems offer certain benefits, some do not provide the necessary framework for researchers and some do not provide realistic groupings for purposes of industry benchmarking. Furthermore, in many cases, classification systems are not compatible with one another. This article reviews some of the systems that are currently in use and argues for the need for a single common classification system. Finally, it proposes a new system, based on certain operational factors, which can be used by both industry and academics in the effort to provide consistency across academia and industry.

A Study of Efficiency in a Reduced Matrix Converter for Offshore Wind Farms

Reduced matrix converter (RMC) is a convenient topology for offshore wind farm due to its potential to reduce the size and weight of the converter, to improve the reliability by removing the electrolytic capacitor, and to increase the efficiency inherent to less stages of conversion. Moreover, it is a very flexible topology which permits different types of operation with a simpler modulation compared with conventional three-phase matrix converter. This paper investigates different modulation strategies applied to RMC for offshore wind farms, focused on efficiency improvement of the entire convention system. Simulation results using a detailed loss model for high-power level are presented. Four cases are investigated according to the modulation strategies (space vector modulation and carrier-based modulation) and the operation principle (current source converter or voltage source converter). Losses in the clamp circuit are also calculated. Different wind velocities are considered in the simulations. Results show that current source operation with space vector modulation presents minimum losses at nominal wind velocity. This operation is suitable for series connection of offshore wind farms which has been reported as the most efficient alternative from the grid losses point of view.