Past Operation Research Articles

Preoperative Anxiety and Social Support among Patients undergoing Surgery

Most patients awaiting surgery experience anxiety. The study aims to assess the levels of preoperative anxiety and social support, determine the association of background variables with levels of preoperative anxiety and social support and to examine the relationship between levels of preoperative anxiety with social support. A hospital based cross-sectional study was conducted among patients undergoing surgery in a government Hospital, Pokhara. The study period was from September 2016 to August 2017. Total sample was 442 patients scheduled for surgery. Data was collected through Anxiety Specific to Surgery Questionnaire for anxiety and Multidimensional Scale of Perceived Social Support through face to face interview. Ethical approval was obtained from IRC, Institute of Medicine, Tribhuvan University. Data were entered and analysis was performed with the help of the Statistical Package for Social Science (SPSS).The total 94.1 percent of patients were married and 52 percent had low living standard. High level of preoperative anxiety and social support are seen in 42.1 and 64.3 percent respectively. Preoperative anxiety had significant statistical association with standard of living, experience of past operation, and types of operation(p<0.05). Social support had significant statistical association with age, gender, residence, standard of living, and types of operation (p<0.05). Correlation between preoperative anxiety and social support insignificant (r = -.133, p = 0.005) at the 0.05 level. As social support increased; preoperative anxiety decreased. Therefore, health care provider should identify patients with high anxiety, encourage them to talk about their feelings and facilitate more time with their families.

Conflicting outcomes of an integrated approach to sediment quality assessment in a Sardinian coastal area subjected to mining activities

Multidisciplinary research was carried out to verify the best approach for a reliable assessment of sediment quality in marine areas affected by strong metal enrichment. The study was carried out on Sulcis-Iglesiente marine coastal areas (Sardinia, Italy), where a long-lasting past mining operation strongly contaminated marine sediments with heavy metals (Cd, Pb and Zn). Surface sediments were analysed for grain size and mineralogical content, total organic carbon, total metal concentrations and sequential extractions. Additionally, ecotoxicological bioassays were performed using Vibrio fischeri (Microtox®) on the solid phase and elutriate, Dunaliella tertiolecta on elutriate and Brachionus plicatilis on elutriate. Analysed sediments were nearly exclusively sand (98.5–100%) with a very low TOC content; their texture and mineralogy indicated a N-S drift affecting the dispersion of mining contributions. The total concentrations of Cd, Pb and Zn, which are positively correlated, exceeded background and Environmental Quality Standards (EQS) values by up to two orders of magnitude, while sequential extractions revealed their high mobility because Cd and Pb were mainly extracted in the first phase (up to 77 and 82%, respectively) and Zn in the second phase (up to 99%). In spite of this, bioassays recorded the absence of toxicity in all the samples. These apparently conflicting results suggest that ecotoxicological tests cannot replace chemical analyses in sediment quality assessments because they could fail to provide reliable information on the bioavailability of contaminants over time.

Analysis and management of multi-species fisheries: Small-scale finfish fishery at Bahía Magdalena- Almejas, Baja California Sur, Mexico

Fishing is an important activity contributing to countries’ economy and food security worldwide. Despite efforts towards sustainability, fisheries frequently face overexploitation situations, particularly small-scale fisheries (SSF) whose management needs to be improved, according to the United Nations 2030 agenda. SSF are characterised as complex and predominantly multi-species activities, with little information available regarding their past and current operation. In Mexico, finfish fishery has played a fundamental role in recent years, but there are only official norms for four species and basic precautionary measures have been established by national regulations without applying a multi-species management scheme to this group. The present study was conducted to generate information that facilitates understanding how the finfish fishery operates. The research, completed in the Magdalena-Almejas Bay region, included the integration of productive units, the fleet operation, and the relation between target and associated species. The methodology encompassed an analysis of official catch landing reports data, official statistics between 1998 and 2008, and local knowledge gathered through surveys of producer organizations. Among the results, 75 fish species from 23 families were considered of commercial importance; however, 94% of the catches only include 10 families and were geographically located at 140 fishing localities. An oscillatory catch pattern throughout years was found, with the main fishing season being from May to August. The operative unit of the finfish fleet was integrated by fiberglass measuring 24 ± 3 feet, equipped with a four-stroke gasoline engine of 86 ± 40 HP. The target species were identified and compared to the fishing gear in use, capture zones, and associated species, aspects that allow an understanding of how the fishing works and provide important input to enhance métier identification processes.

Capacity-based performance measurements for loading equipment in open pit mines

The purpose of this study is to develop an integrated framework for capacity analysis to address the influence of systematic hazardous factors on the haulage fleet nominal capacity. The proposed model was made to capture unexpected risks for mining equipment based upon data-driven method considering different scenarios. Probabilistic risk assessment (PRA) was employed to quantify the loss of production capacity by focusing on severity of failure incidents and maintainability measurements. Discrete-event simulation was configured to characterize the nominal capacity for mining operation. Accordingly, the system capacity was analyzed through the comparison of nominal and actual capacity. A case study was completed to validate the research methodology. The past operation and maintenance field data were collected for shovel operation. The discrete-event simulation was developed to estimate the rate of shovel nominal capacity. Then, the effects of undesirable scenarios were assessed by developing the PRA approach. The research results provide significant insights into how to enhance the production capacity in mines. The analyst gets a well judgment for the crucial elements dealing with high risk levels. A holistic maintenance plan can be developed to mitigate and control the losses.

The Technological Solution for Management of Toxic Wastes Accumulated in the Last Century (on the Example of the Closed Mining Enterprise in the Primorsky Krai)

Natural-mining technogenic systems formed within the boundaries of the tailings toxic waste impact of the closed Khrustalnensky GOK mining enterprise (the Primorsky Krai) were the object of research. The article presents the data of the long-term researches of the problem for development of technological solution of the accumulated mineral processing toxic wastes management. Exposed to weathering and transformation into new forms, they migrate with groundwater and air flows, having negative impact on ecosphere and human being. Considering this, the aim of the research was to substantiate the need to develop a technological solution for the management of toxic wastes based on the assessment of the present state of the technogenic system and modeling to develop a new technology of liquidation of accumulated environmental damage of the past operation of the former Khrustalnenskiy GOK mining enterprise. Based on the aim of the study, a fundamental research task was established. It includes the scientific basis of assessment and prognosis of environment situation adverse changes. It is established that the technological solution of toxic mining wastes management is based on the results of experimental researches, proposed criteria and principles of ecological rehabilitation of the tailings surface, mining-environmental monitoring of environment objects changes, mathematical modeling of transfer and accumulation of toxic waste technogenic pollution, based on the fundamental principles of hydraulics and engineering hydrology, updating and developing the database of mining and environmental monitoring of ecosystems within the tailings impact boundaries, with regard to the calculation of the pollutants dispersion in the biosphere in the GIS MapInfo-6.0 format.

Source identification and evaluation of surface water quality using factor and discriminant analysis

This study utilizes factor and discriminant analysis to identify the parameter source and evaluate the quality of water from ex-mining ponds and lakes in Selangor. Factor analysis (FA) which explain 83.77% of the surface water quality variation shows that As and Cd that mostly originated from mining activity, and pH are the parameters responsible for the major variation in the surface water quality and were strongly associated with varimax factor 1 (VF1), while Pb, Mn and DO were associated with varimax factor 2 (VF2). The Discriminant analysis (DA) reveals that As, Cd, Mn, Fe and pH are the parameters that significantly differentiate ex-mining ponds from the lake (p > 1), and supported by the correlation study. The elevated metal concentrations in ex-mining ponds compared to lakes were plausibly associated with the past mining operation, thereby indicating heavy metal dominance in ex-mining ponds. DO and BOD are associated with the anthropogenic input from residential sources. Findings of this study therefore show the need and usefulness of multivariate statistical analysis to get information on the quality status of surface water. Keywords : Discriminant analysis, Ex-mining pond, Factor analysis, Lake, Water quality.

Detection of anomalous zones in a rock-mass, caused by past shallow extraction of zinc, lead and silver ore

Article discusses one of the geophysical prospecting methods (electrical resistivity method) used for solving environmental geoengineering problems. Studying bedding (rock mass) using non-invasive geophysical methods is beneficial particularly because of the ability to obtain complete and very accurate information, depending on adopted research and prospecting approach. Interpretation of geophysical data, should always include available geological, empirical and environmental information, while all results should be presented on integrated profiles and maps. This article presents the idea and the possibility of using the geophysical electrical resistivity method in order to detect anomalous zones in rock mass that may lead to formation of so called discontinuities (fractures), which are the result of past shallow ore mining operation in discussed Tarnowskie Góry area .

Post-Operative Complications After Repair Of Incisional Hernia

AbstractBackground:-Incisional hernia is frequently met by the general surgeon, itis frequently complicated (3.8-11.5%)of patients after abdominal surgery. Repair oflarge incisional hernia is a difficult surgical problem with recurrence being a common. Numerous methods of repair have been described simple opposition in one layer orcomplex opposition and the use of prosthetic mesh. The aim of this study is to report our experience with the use of mesh repair and risk factors that influence post operative complications.Methods:-A prospective study done in Al-hussain teaching Hospital, Department of Surgery between January 2011 to December 2013.One hundred and ten patients with prosthetic repair of incisional hernia were included in this study. History was taken and thorough examination was done, all patients were asked for history of diabetes mellitus, obesity, corticosteroid use, their original operations,primary or recurrent hernia and examined for their body mass index, size and duration of the hernial defect were recorded. A proforma was completed for each patient, noting prophylactic antibiotics hadbeen given or not, type of the sac and whether opened or inverted, type and size of mesh had been used, intraoperative and postoperative complications and postoperativehospital stay. 
 Results:-Of (110) patients, (62) were females, (48)were males,their median age was(45.5) years for women and (58) years for men,(31)patients(28.2%)weighted more than their ideal body weight and had body mass index equal or more than(30).Forty eight patients (43.6%) were diabetic and (24)patients(21.8%)were corticosteroid used. The original operations were bowel related and gynecological in the majority ofpatients. Previous incisions were long midline in(38) .Twenty patients had one past operation, (13)had two,(5) had three and one patient had four past repair, theremaining were new Incisional hernia patients. The main hernia size was (12.3) cm and (4.6) cm in vertical and horizontal direction respectively. Forty four patients had additional surgical procedures, consisted of Fallopian tube ligation in (12) ,division of small bowel adhesions in (8) ,suturing of small bowel perforation in (4) and abdominoplasty in (20) patients. In the majority of patients (78), standard polypropylene mesh had been used and vicryl-prolene (Vypro) mesh in the remaining (32) patients. The main postoperative complications were seroma formation (17.3%), wound haematoma (10%), wound infection (9.1%), chest infection (6.4%), one patientdeveloped intestinal fistula and mesh need to be removed. Five recurrent incisional hernias occurred. Most patients developed complications were obese, diabetic and corticosteroid used. No death in our series.Conclusion:-Tension free incisional hernia repair using prosthetic mesh is a safe and easy procedure with no major morbidity or recurrence. The patient-doctor should advise weight loss to help reduce risks of surgery and improve the surgical results. Control of diabetes, corticosteroid drug use and smoking cessation are recommended for better results. Rigid sterile condition, precise and meticulous technique with the use of closed suction drains is important.

Start-Up Optimization of Combined Cycle Power Plants: A Field Test in a Commercial Power Plant

Requirements for the start-up operations of gas turbine combined cycle (GTCC) power plants have become more diverse and now include such items as reduced start-up time, life consumption, and fuel gas consumption. In this paper, an optimization method is developed to solve these multi-objective problems. The method obtains optimized start-up curves by iterating the search for the optimal combination of the start-up parameter values and the evaluation of multiple objective functions. The start-up curves generated by this method were found to converge near the Pareto-front representing the best trade-off between the fuel gas consumption of the gas turbine (GT) and thermal stress in the steam turbine (ST) rotor which are defined as the objective functions. To demonstrate the effectiveness of the developed method, field tests were performed in a commercial power plant. As a result, the fuel gas consumption of HOT start-up was reduced by 22.8% compared with the past operation data. From this result, the developed method was shown to be capable of optimizing the start-up process for GTCC power plants.

Crustal evolution and mantle dynamics through Earth history.

Resolving the modes of mantle convection through Earth history, i.e. when plate tectonics started and what kind of mantle dynamics reigned before, is essential to the understanding of the evolution of the whole Earth system, because plate tectonics influences almost all aspects of modern geological processes. This is a challenging problem because plate tectonics continuously rejuvenates Earth's surface on a time scale of about 100 Myr, destroying evidence for its past operation. It thus becomes essential to exploit indirect evidence preserved in the buoyant continental crust, part of which has survived over billions of years. This contribution starts with an in-depth review of existing models for continental growth. Growth models proposed so far can be categorized into three types: crust-based, mantle-based and other less direct inferences, and the first two types are particularly important as their difference reflects the extent of crustal recycling, which can be related to subduction. Then, a theoretical basis for a change in the mode of mantle convection in the Precambrian is reviewed, along with a critical appraisal of some popular notions for early Earth dynamics. By combining available geological and geochemical observations with geodynamical considerations, a tentative hypothesis is presented for the evolution of mantle dynamics and its relation to surface environment; the early onset of plate tectonics and gradual mantle hydration are responsible not only for the formation of continental crust but also for its preservation as well as its emergence above sea level. Our current understanding of various material properties and elementary processes is still too premature to build a testable, quantitative model for this hypothesis, but such modelling efforts could potentially transform the nature of the data-starved early Earth research by quantifying the extent of preservation bias.This article is part of a discussion meeting issue 'Earth dynamics and the development of plate tectonics'.

A framework for reconciliating data clusters from a fleet of nuclear power plants turbines for fault diagnosis

When a fleet of similar Systems, Structures and Components (SSCs) is available, the use of all the available information collected on the different SSCs is expected to be beneficial for the diagnosis purpose. Although different SSCs experience different behaviours in different environmental and operational conditions, they maybe informative for the other (even if different) SSCs. In the present work, the objective is to build a fault diagnostic tool aimed at capitalizing the available data (vibration, environmental and operational conditions) and knowledge of a heterogeneous fleet of P Nuclear Power Plants (NPPs) turbines. To this aim, a framework for incrementally learning different clusterings independently obtained for the individual turbines is here proposed. The basic idea is to reconciliate the most similar clusters across the different plants. The data of shut-down transients acquired from the past operation of the P NPPs turbines are summarized into a final, reconciliated consensus clustering of the turbines behaviors under different environmental and operational conditions. Eventually, one can distinguish, among the groups, those of anomalous behavior and relate them to specific root causes. The proposed framework is applied on the shut-down transients of two different NPPs. Three alternative approaches for learning data are applied to the case study and their results are compared to those obtained by the proposed framework: results show that the proposed approach is superior to the other approaches with respect to the goodness of the final consensus clustering, computational demand, data requirements, and fault diagnosis effectiveness.

Authority to Carry in the United Kingdom: The Right to Travel, the Privatization of Security and the Rule of Law

The rights to enter and exit the United Kingdom are limited in a number of ways which have in common a desire to protect the national security of the country. One of the relevant mechanisms, the legal basis of which has recently been overhauled, is that of ‘ authority to carry ’ (ATC) schemes, which require transport companies to request permission to bring persons in and out of the UK and punish them if they do so without permission. This article outlines the relevant law and considers it from two points of view: first, the rule of law issues raised by the past and present operation of the relevant schemes and, second, the lessons of ATC schemes for the privatized enforcement of national security norms and the possible attenuation of the scope for legal accountability for their operation.

The oceanic cycles of the transition metals and their isotopes

The stable isotope systems of the transition metals potentially provide constraints on the current and past operation of the biological pump, and on the state of ocean redox in Earth history. Here we focus on two exemplar metals, nickel (Ni) and zinc (Zn). The oceanic dissolved pool of both elements is isotopically heavier than the known inputs, implying an output with light isotope compositions. The modern oceanic cycle of both these elements is dominated by biological uptake into photosynthesised organic matter and output to sediment. It is increasingly clear, however, that such uptake is associated with only very minor isotope fractionation. We suggest that the isotopic balance is instead closed by the sequestration of light isotopes to sulphide in anoxic and organic-rich sediments, so that it is ocean chemistry that controls these isotope systems, and suggesting a different but equally interesting array of questions in Earth history that can be addressed with these systems.

Vested Interests and the Common People in Developing Countries: Understanding Oppressive Societies and Their Effects

:The standard economic model of how economies work is that activities are essentially productive. This is not a correct view of reality. The principal difficulty is that there is economic activity that is unproductive and harmful (from the point of view of those being harmed). This is a central feature of the economic organization of these societies, and creates poverty. The first section of the article discusses the concept of harm. The second section describes how societies are run on this basic set of principles: Take and maintain control of the government and other aspects of society, and use the power of government to obtain income. The third section of the article describes how this system harms the common people. Topics include corruption, misappropriation of natural resources, conflict and other harm engendered by the struggle for control, the influence on present society of the past operation of harmful economic systems, and discrimination as well as other “barriers to entry.”

Clinical comparison of modified laparoscopic and conventional placement of peritoneal dialysis catheters

Objective: To explore the clinical efficacy of the modified laparoscopic placement of peritoneal dialysis catheters by nephrologists. Methods: A total of 188 patients diagnosed as end-stage renal disease (ESRD) were enrolled, who received catheter and continuous ambulatory peritoneal dialysis (CAPD) therapy from January 2011 to May 2016 in Zhejiang Provincial People's Hospital. They were divided into group A (with modified laparoscopic placement of peritoneal dialysis catheters, n=59) and group B (with conventional placement of peritoneal dialysis catheter, n=129). The demographic and clinical characteristics, past abdominal operation history, surgery time, hospital stay after operation, expenses for surgery and hospitalization, early and late complications including bleeding, pain, leakage, peritonitis and catheter displacement were observed. Results: Patients with previous abdominal surgery accounted for 11.9% in group A and 0 in group B(χ2=15.897, P<0.001). The duration of the operation was (38.9±12.8)min in group A and (64.1±12.7)min in group B(t=-6.466 6, P=0.000 0). The cost of the operation was (5 488.4±156.1) yuan in group A and (1 602.7±48.92) yuan in group B (t=257.129, P=0.000 0). Catheter displacement within one month was observed in 0 and 11.6%(χ2=7.455 3, P=0.003), pain in 15.3% and 41.9% (χ2=12.862 2, P=0.000), and catheter displacement after one month in 0 and in 16.3% (χ2=10.812 4, P=0.000) of the patients, respectively in group A and group B. The incidences of peritonitis within one month and beyond one month, leakage, bleeding and so on showed no difference between the two groups(P>0.05). Conclusions: Placement of PD catheter with laparoscope is suitable for renal failure patients with abdominal operation history and replacement PD catheter. It also has the advantages of shorter surgery time, less pain and lower incidences of catheter displacement, expanding the application of PD. However, bleeding, leakage, hernia and other complications are frequently seen.

Energy efficiency performance-based prognostics for aided maintenance decision-making: Application to a manufacturing platform

Nowadays, industrial enterprises are facing up to new challenges to well optimize their performances, with regards not only to conventional performances (e.g. reliability or productivity) but also to emerging ones as those related to sustainability issues. Indeed, sustainability indicators have to be considered now in the decision-making process of the plant to better control and maintain it to be consistent with Green Production requirements. In that way, indicators such as Energy Efficiency or Energy Consumption are promoted for the impact they have on these requirements in a Life Cycle Cost vision. Thus the core idea defended in this paper is addressing the necessary evolution of conventional maintenance decision-making process in industry for considering the energy efficiency indicator. To support the idea, the first objective is to define the concept of energy efficiency indicator which materializes the energy efficiency performance at a specific time. The definition is done for different abstraction levels such as component, function, system which are subjected to time-dependent degradation behaviors. So, the energy efficiency indicator concept is expressed as the amount of energy consumed per unit of useful output, which has to be seen as a sustainable performance measure of industrial system. Then a mathematical formulation is proposed to calculate energy efficiency indicator at any time of the performance by considering dependent factors (static and dynamic ones) impacting inputs and outputs of the system. The second objective is to propose a new concept named REEL (Remaining energy-efficient lifetime) for tracking the energy efficiency performance evolution. The REEL is defined by the time left before the system loses its energy efficiency property considered as a specific EEI value (EEI threshold) not to be exceeded. This specific value is technically and/or economically fixed in advance, given the current condition, past and future operation profiles. The REEL could be used as an appropriate indicator for maintenance decision-making process in a proactive vision. The third objective is to formalize a generic approach in the way assess the REEL value. The assessment requires to forecast the evolution of energy efficiency indicator (whatever the abstraction level is) by taking into account the static and dynamic factors. Finally, the feasibility and added value of our proposals are illustrated on a manufacturing platform named TELMA (TELeMAintenance).

International Criminal Law as a Spotlight and Black Holes as Constituents of Legacy

This contribution engages with Sara Kendall’s and Sarah Nouwen’s article on the legacy of the International Criminal Tribunal for Rwanda (ICTR) and their call for an ethos of institutional modesty. I much support the nuanced approach that underlies their call and I see it as a prerequisite to properly and adequately appreciate the ICTR’s past existence and operation. I would even be open to moving one step further in the direction of an ethos of sobriety. Rather than seizing the momentum to celebrate accomplishments and highlight milestones, legacy-talk and legacy-construction of international criminal tribunals should entail a form of reckoning. Indeed, as suggested by Kendall and Nouwen, the “justices not done” and the “justices pending” must be part and parcel of the ICTR’s legacy-constructions so as to offer a fair balance and to capture the ICTR’s overall performance, explicitly accounting for results as well as omissions.

Pathologic lesions of the fetuses and placentas induced by decidual vasculopathy

Pathologic lesions of the fetuses and placentas induced by decidual vasculopathy

Postoperative voiding difficulty and mesh-related complications after Total Prolift System surgical repair for pelvic organ prolapse and predisposing factors.

We aimed to evaluate the incidence and predisposing factors of postoperative voiding difficulty and mesh-related complications. In this prospective cohort study, 206 consecutive women with advanced pelvic organ prolapse underwent surgical repair with the Prolift mesh kit at Peking Union Medical College Hospital, with a mean follow-up of 4.2 years. Postoperative voiding difficulty was defined as postvoid bladder volume of 100 mL or more (or more than one third of voided volume). The International Urogynecological Association/International Continence Society joint terminology was used for mesh-related complications and pain. Symptomatic recurrence was defined as symptomatic Pelvic Organ Prolapse Quantification stage II or higher. χ test and univariate or multivariate logistic regression were used for data analysis. Fourteen (6.8%) women were lost to follow-up. Postoperative voiding difficulty occurred in 60 of 192 (31.25%) women; low preoperative average urine flow (odds ratio [OR], 4.7; 95% CI, 1.3-17.2) and residual urine volume (OR, 2.6; 95% CI, 1.3-5.0) were independent risk factors. In total, 85% (51 of 60) reported symptom resolution within 3 days. Women with a postoperative residual urine volume of 200 mL or more experienced a more difficult recovery (P = 0.01). Mesh-related complications were reported in 29 of 192 (15.1%) women, with vaginal complications (mesh exposure/contraction) accounting for 69.0% (20 of 29). Greater blood loss (OR, 5.9; 95% CI, 2.1-18.7) and past pelvic surgical operation (OR, 6.3; 95% CI, 1.3-23.8) were strongly related to these complications. Three hematomas (7A) and six skin complications (6B) were also reported. However, the small participant sample prevented pain and recurrence analyses. Low average urine flow rate and preoperative urinary retention can be used to predict postoperative voiding difficulty. Vaginal complications (mesh exposure/contraction) are the primary mesh-related complications and are predicted by greater blood loss and past pelvic surgical operation.

KEKB/TRISTAN 超伝導空洞用大型ヘリウム冷却システム

This article describes the configuration and heat loads of the large-scale helium refrigeration system for the superconducting cavities utilized for the TRISTAN and KEKB Factory accelerators. The control system of the refrigeration system is also introduced. The fatal failures of the refrigeration system during the past long-term operation are summarized to entice discussions on future stable operation of the refrigeration system, since the refrigeration system will also be used for the SuperKEKB superconducting cavities