Econophysics and the Entropic Foundations of Economics.

This paper examines relations between econophysics and the law of entropy as foundations of economic phenomena. Ontological entropy, where actual thermodynamic processes are involved in the flow of energy from the Sun through the biosphere and economy, is distinguished from metaphorical entropy, where similar mathematics used for modeling entropy is employed to model economic phenomena. Areas considered include general equilibrium theory, growth theory, business cycles, ecological economics, urban-regional economics, income and wealth distribution, and financial market dynamics. The power-law distributions studied by econophysicists can reflect anti-entropic forces is emphasized to show how entropic and anti-entropic forces can interact to drive economic dynamics, such as in the interaction between business cycles, financial markets, and income distributions.

The feasibility of using 'bring your own device' (BYOD) technology for electronic data capture in multicentre medical audit and research.

Large-scale audit and research projects demand robust, efficient systems for accurate data collection, handling and analysis. We utilised a multiplatform 'bring your own device' (BYOD) electronic data collection app to capture observational audit data on theatre efficiency across seven hospital Trusts in South Yorkshire in June-August 2013. None of the participating hospitals had a dedicated information governance policy for bring your own device. Data were collected by 17 investigators for 392 individual theatre lists, capturing 14,148 individual data points, 12, 852 (91%) of which were transmitted to a central database on the day of collection without any loss of data. BYOD technology enabled accurate collection of a large volume of secure data across multiple NHS organisations over a short period of time. Bring your own device technology provides a method for collecting real-time audit, research and quality improvement data within healthcare systems without compromising patient data protection.

Complexity and behavioral economics.

This paper will consider the relationship between complexity economics and behavioral economics. A crucial key to this is to understand that Herbert Simon was both the founder of explicitly modern behavioral economics as well as one of the early developers of complexity theory. Bounded rationality was essentially derived from Simon's view of the impossibility of full rationality on the part of economic agents. Modern complexity theory through such approaches as agent-based modeling offers an approach to understanding behavioral economics by allowing for specific behavioral responses to be assigned to agents who interact within this context, even without full rationality. Other parts of modern complexity theory are considered in terms of their relationships with behavioral economics. Fundamentally, complexity provides an ultimate foundation for bounded rationality and hence the need to use behavioral economics in a broader array of contexts than most economists have thought appropriate.

Chaos theory before Lorenz.

We consider the precursors to the discovery of sensitive dependence on initial conditions by Edward Lorenz (1963) in his model of climatic fluid dynamics. This will focus on work in various disciplines that imply either such sensitivity, irregular endogenous dynamic patterns, or fractal nature of an attractor, as is also found in the attractor underlying the model Lorenz studied. Going from ancient hints in Anaxagoras through nineteenth century mathematics and physics, the main areas of such development will be argued to have been in celestial mechanics, oscillators, and economics.

Microfluidic nutrient gradient-based three-dimensional chondrocyte culture-on-a-chip as an in vitro equine arthritis model.

In this work, we describe a microfluidic three-dimensional (3D) chondrocyte culture mimicking in vivo articular chondrocyte morphology, cell distribution, metabolism, and gene expression. This has been accomplished by establishing a physiologic nutrient diffusion gradient across the simulated matrix, while geometric design constraints of the microchambers drive native-like cellular behavior. Primary equine chondrocytes remained viable for the extended culture time of 3 weeks and maintained the low metabolic activity and high Sox9, aggrecan, and Col2 expression typical of articular chondrocytes. Our microfluidic 3D chondrocyte microtissues were further exposed to inflammatory cytokines to establish an animal-free, in vitro osteoarthritis model. Results of our study indicate that our microtissue model emulates the basic characteristics of native cartilage and responds to biochemical injury, thus providing a new foundation for exploration of osteoarthritis pathophysiology in both human and veterinary patients.

Debating the role of econophysics.

Research in econophysics has been going on for more than a decade with considerable publicity in some of the leading general science journals. Strong claims have been made by some advocates regarding its reputed superiority to economics, with arguments that in fact the teaching of microeconomics and macroeconomics as they are currently constituted should cease and be replaced by appropriate courses in mathematics, physics, and some other harder sciences. The lack of invariance principles in economics and the failure of economists to deal properly with certain empirical regularities are held against it in this line of argument. Responding arguments address four points: (a) that many econophysicists lack awareness of what has been done in economics and thus sometimes claim a greater degree of originality and innovativeness in their work than is deserved, (b) that econophysicists do not use as sufficiently rigorous or sophisticated statistical methodology as econometricians, (c) that econophysicists search for universal empirical regularities in economics that probably do not exist, and (d) that the theoretical models they adduce to explain empirical phenomena have many difficulties and limits. This article examines the arguments and concludes that nonlinear dynamics and entropy concepts may provide a productive way forward.

Do nonlinear dynamics in economics amount to a Kuhnian paradigm shift?

Much empirical analysis and econometric work recognizes that there are nonlinearities, regime shifts or structural breaks, asymmetric adjustment costs, irreversibilities and lagged dependencies. Hence, empirical work has already transcended neoclassical economics. Some progress has also been made in modeling endogenously generated cyclical growth and fluctuations. All this is inconsistent with neoclassical general equilibrium. Hence there is growing evidence of Kuhnian anomalies. It therefore follows that there is a Kuhnian crisis in economics and further research in nonlinear dynamics and complexity can only increase the Kuhnian anomalies. This crisis can only deepen. However, there is an ideological commitment to general equilibrium that justifies "free enterprise" with only minimal state intervention that may still sustain neoclassical economics despite the growing evidence of Kuhnian anomalies. Thus, orthodox textbook theory continues to ignore this fact and static neoclassical theory remains a dogma with no apparent reformulation to replace it.

A stone extraction facilitation device to achieve an improved technique for performing LCBDE.

BACKGROUND: Laparoscopic common bile duct exploration (LCBDE) has proved to be a safe, cost-effective way to treat common bile duct (CBD) stones. Despite this, LCBDE has not gained widespread adoption by surgeons. The technique has proved difficult to master, and damage to the fragile choledochoscope by grasping forceps and passage through the port valves has been problematic. Cases involving large, impacted, or multiple stones have required conversion to open exploration of CBD. METHODS: The Multichannel Instrument Guide (MIG) is introduced as a solution for these problems. The MIG is a J-shaped plastic extrusion with three lumens. It is flexible and can be straightened for insertion through a 10-mm port. The MIG facilitates insertion of a flexible 2.8- to 3.2-mm choledochoscope into the CBD. At the same time, additional tools such as balloon or irrigation catheters and lithotripters can be introduced into the CBD. These can be manipulated under video guidance via the choledochoscope. This procedural multitasking allows for a more efficient LCBDE. The authors describe their initial experience using the MIG for 23 patients. RESULTS: Of the 23 patients who underwent LCBDE procedures, 20 had stones in the CBD. Multiple stones were present in 48% of the patients; impacted stones were present in 26% of the patients; and stones larger than 1 cm were present in 26% of the patients. A 95% stone clearance rate was achieved. Difficult cases with large, impacted or multiple stones were resolved using the MIG. Two choledochoscopes were damaged; one during surgery and one during cleaning and storage. CONCLUSIONS: The MIG has demonstrated significant advantages over previously described techniques. The device secures biliary tract access and allows procedural multitasking while protecting the delicate and expensive equipment. Subsequently, a simplified technique algorithm can be followed that may encourage more surgeons to adopt the routine performance of LCBDE.

Skill acquisition and assessment for laparoscopic surgery.

OBJECTIVES: To describe a training method with objective evaluation to enhance laparoscopic surgical skills to provide training in laparoscopic suturing techniques and to assess whether specific training exercises were helpful in the attainment of intracorporeal suturing skills. DESIGN: Trainees (N = 150) were asked to perform standardized drills with distinct mechanical features, and skill acquisition was determined by accuracy and timing. Trainees were tested for the ability to perform an intracorporeal laparoscopic suture before and after analogous skill training with the drills. SETTING: The training courses were held in teaching and nonteaching hospitals. PARTICIPANTS: Board-certified or board-eligible surgeons. MAIN OUTCOME MEASURES: Supervision by trained instructors and documentation of the time required to perform standardized drills. RESULTS: The trainees showed steady improvement in skill acquisition during 10 trials (P < .001). Significant (P < .001) improvement was noted for the performance of suturing after compared with before the drills. CONCLUSION: Three standardized laparoscopic drills have been tested in 150 trainees and demonstrate the incremental acquisition of skills that correlate with improved performance in a challenging and complex laparoscopic skill, intracorporeal suturing.

Objective evaluation of a laparoscopic surgical skill program for residents and senior surgeons.

BACKGROUND: Laparoscopic surgery adapts poorly to apprenticeship models for general surgical training. Standardized skill acquisition and validation programs, targeted performance goals, and a supervised, enforced, skill-based curriculum that readily can be shared between trainee and instructor must replace the observation and incremental skill-acquisition model used in an open surgical environment. The Yale Laparoscopic Skills and Suturing Program was used to develop a data bank for objective evaluation of dexterity and suturing skills for laparoscopic surgical training. The current study compares trainee and senior surgeon performance in this standardized training program. OBJECTIVE: To compare objectively evaluated laparoscopic surgical skills and suturing capability of senior surgeons and of residents after they have completed the same standardized training regimen. METHODS: Two hundred ninety-one trained surgeons performed 8730 standardized laparoscopic dexterity drills and 2910 intracorporeal suturing exercises in the Yale Laparoscopic Skills and Suturing Program. Their performance was supervised by an instructor who recorded performance and timing of the tasks in a 2 1/2-day program. Ninety-nine residents performed the same drills and exercises the same number of times and followed the same technique for intracorporeal suturing. Percentile graphs were prepared for each type of drill and suturing exercise to allow comparison of levels of achievement among different training groups. RESULTS: The performance of the residents was the same as that of trained surgeons for the rope pass drill and the suturing exercise. Residents in comparison with trained surgeons performed the triangle transfer drill faster and the new cup drop drill and old cup drop drill more slowly. There was no significant difference in performance between male and female residents. CONCLUSION: Basic skills relevant to laparoscopic performance can be acquired with a high level of competence in a brief course unrelated to prior surgical experience, sex, or age.

Evaluation of the effectiveness of portable low-bandwidth telemedical applications for postoperative followup: initial results.

BACKGROUND: The idea of using telemedical applications to evaluate patients remotely is several decades old. It has already been established that x-ray images (and magnetic resonance images) can be transferred using a personal computer and a modem, and many other such applications have been implemented. Over the past 50 years the expense and technical demands of the equipment involved in telemedicine have hindered its widespread deployment. The purpose of this study is to evaluate the ability of a mobile, low-bandwidth telemedicine platform to achieve real-time postoperative visits in the home. STUDY DESIGN: This evaluation was designed to evaluate the feasibility of performing a real-time clinical visit with computer and telecommunications hardware and software. A nurse and medical student (for information gathering only) made postoperative visits at patients' homes while the physician stayed at the office. Clinical evaluations were performed by using low-resolution and frame-rate video, high-resolution still images, and simultaneous telephony over a standard telephone line. These remote visits were followed by a standard visit in the office. Eleven patients were included, all of whom had undergone various laparoscopic procedures. They lived 5 to 240 miles from their surgeon. Efficiency was measured by recording the time required to capture and send data required by the physician to make a clinical decision. The time expense was measured at both the patients' and physician's locations. Technical issues were evaluated and patient satisfaction was assessed by standardized objective questionnaires. The accuracy of the evaluation at the remote visit was determined with a standard office visit. RESULTS: No technical problems were observed. The mean total time of the housecall at the remote site was 86 minutes (range 60 to 160 minutes) and at the base station site was 41 minutes (range 21 to 71 minutes). After personnel became familiar with the system, the last three visits averaged 61 and 25 minutes at the two sites, respectively. This corresponds favorablywith current time requirements for visiting nurses and office visits. The patients were highly satisfied with the home visit and, on average, rated the experience as 4.8 out of a maximum of 5. CONCLUSIONS: Followup visits in patients' homes after laparoscopic procedures can be accomplished by transmitting simultaneous voice, low-resolution video, and high-resolution still images to accurately perform postoperative evaluations over standard telephone lines, with time requirements and clinical accuracy similar to those of standard visits.

Use of mobile low-bandwith telemedical techniques for extreme telemedicine applications.

BACKGROUND: Telemedicine is traditionally associated with the use of very expensive and bulky telecommunications equipment along with substantial bandwidth requirements (128 kilobytes per second [kbps] or greater). Telementoring is an educational technique that involves real-time guidance of a less experienced physician through a procedure in which he or she has limited experience. This technique has been especially dependent on the aforementioned requirements. Traditionally, telemedicine and telementoring have been restricted to technically sophisticated sites. The telemedicine applications through the existing telecommunication infrastructure has not been possible for underdeveloped parts of the world. STUDY DESIGN: Telemedicine and telementoring were applied using low-bandwidth mobile telemedicine applications to support a mobile surgery program in rural Ecuador run by the Cinterandes Foundation and headed by Edgar Rodas, MD. A mobile operating room traveled to a remote region of Ecuador. Using a laptop computer equipped with telemedicine software, a videoconferencing system, and a digital camera, surgical patients were evaluated and operative decisions were made over low-bandwidth telephone lines. Similarly, surgeons in the mobile unit in Ecuador were telementored by an experienced surgeon located thousands of miles away at Yale University School of Medicine. RESULTS: Five preoperative evaluations were conducted from Sucua to Cuenca, Ecuador, with excellent clinical correlation. Additionally, a laparoscopic cholecystectomy was successfully telementored from the department of surgery at Yale University School of Medicine to the mobile surgery unit in Ecuador. The telementored surgery was performed using a telephone line with a baud rate of 12 kbps. CONCLUSIONS: Mobile, low-bandwidth telemedicine applications used in the proper technical and clinical algorithms can be very effective in supporting remote health care delivery efforts. Advantages of such applications include increased cost-effectiveness by limiting travel, expanding services to patients, and increased patient quality assurance.

Measurement of the effective size of the input phosphor of an x-ray image intensifier.

A technique is described, using a mobile radiographic x-ray unit, for determining the effective size of the input phosphor of an image intensifier (I.I.), in particular for a unit with over-table x-ray tube, under-table II, and with the I.I. physically inaccessible. The techniques described also enable (1) locating the central axis of the I.I.; (2) the ratio, R, of the dimensions of the radiological image incident upon the front of the I.I. to the dimensions of the image on the monitor screen; and (3) the distance between the input phosphor and the table top, which is needed to determine the distance from focal spot to input phosphor.

Surgeon-specific factors in the acquisition of laparoscopic surgical skills.

BACKGROUND: Training and experience vary widely among surgeons performing laparoscopic surgery (LS). Visual perceptual demands are greater for LS than for traditional surgery, necessitating greater understanding of surgeon variables in skill acquisition and performance. METHODS: During an LS skills course incorporating didactic and simulator-based instruction, 94 surgeons completed an experience/demographic questionnaire, a test of course-specific knowledge acquisition, 10 trials of three dexterity drills, 15 suturing trials using course-specific methods, and 3 standardized tests of visual perception. RESULTS: Age, years posttraining, and visual perception correlated significantly with time required to complete drills and suturing trials (Pearson correlations ranged from r = 0.21, P <0.05, to r = 0.51, P <0.001) even after statistically controlling for variations in knowledge acquisition, which correlated (r = 0.30, P <0.01) with suturing speed. CONCLUSIONS: Surgeon variables play a significant role in speed of acquisition and performance of LS skills. Further studies need to elucidate their role in quality of LS performance.

Effectiveness of a CD-ROM multimedia tutorial in transferring cognitive knowledge essential for laparoscopic skill training.

BACKGROUND: Computer-assisted instruction (CAI) can benefit surgical education by improving efficiency, effectiveness, standardization, and access. This study compares knowledge gains for laparoscopic skill acquisition following a standardized tutorial delivered via CD-ROM versus live instructor. METHODS: A standardized tutorial was written and subsequently converted to multimedia CD-ROM format by its author (JR). During a laparoscopic development course, experienced US-trained surgeons (n = 52) participated in the tutorial delivered live by the author. The CD-ROM tutorial replaced the instructor for the following groups: (1) experienced US-trained surgeons (n = 27); (2) US-trained surgical residents (n = 59); and (3) Greek surgeons (n = 63). A 51-item knowledge test was administered before and after tutorial instruction. RESULTS: The mean increase in scores between pretest and posttest was significant (P <0.01) and of similar magnitude in each group, with nonsignificant posttest mean differences among US-trained groups. CONCLUSIONS: The CD-ROM tutorial effectively transfers cognitive information necessary for skill development. Distance learning modes of this tutorial program may be feasible.

A simplified technique for laparoscopic jejunostomy and gastrostomy tube placement.

BACKGROUND: Percutaneous endoscopic gastrostomy and jejunostomy tube placement have long been considered the standard for supplying enteral nutrition when oral intake is not possible. Both have well-documented roles and limitations and are associated with a higher than generally appreciated incidence of aspiration. A distally placed tube in the jejunum decreases the chance of this morbid complication. Additionally, when percutaneous endoscopic gastrostomy is indicated but cannot be done for technical reasons, a minimally invasive alternative is desirable. METHODS: In prior series, the techniques suggested for laparoscopic enteral access have characteristics that are either difficult for the average surgeon to duplicate, or use nonstandard anchoring techniques of the bowel to the abdominal wall. A simple, laparoscopically directed, percutaneous technique utilizing cost-effective appliances is described, and suggested indications are outlined. RESULTS: This technique has been successfully applied in 46 patients with minimal complications. CONCLUSIONS: A simplified technique for laparoscopic jejunostomy and gastrostomy tube placement is described. This has been successfully deployed in 46 patients with minimal morbidity. The procedure lessens the need for sophisticated suturing skills and duplicates standard small bowel to abdominal wall fixation methods.

Dilemmas in general practice: the care of the cancer patients.

Recent investigations of the care provided for cancer patients in the community have revealed substantial shortcomings, both in the identification of problems and in the help offered to patients and their families. While some explanations have been sought for these omissions, it has generally been assumed that they are due to practitioners' ignorance of problems encountered by families. Focusing on general practitioners, this paper argues that these deficiencies in care arise not only from ignorance, but also from the conceptual and structural framework within which practitioners operate. Working within such a framework, general practitioners experience considerable dilemmas in decisions about the management and care of cancer patients. This paper argues that explicit acknowledgement of these dilemmas is a necessary prerequisite to any recommendations for improvements in care.

Minimally invasive surgical training solutions for the twenty-first century.

Despite the tremendous impact of laparoscopic cholecystectomy on the practice of surgery over the past 9 years, minimally invasive surgery faces many challenges that must be addressed. SAGES and the American College of Surgeons already have defined guidelines that, if properly implemented, could eliminate most of these challenges. Medical educators must formulate a detailed program as to how these guidelines can be widely deployed with acceptable effectiveness. The current educational philosophies and techniques will not ensure widespread access to a standardized program that would support the achievement of the goals set forth by major surgical governing bodies. Therefore, new educational strategies and techniques that are assisted with the integration of cost-effective technology are needed. Suggested solutions include the deployment of a standardized, objective-based skill-development program that has a large database to evaluate the progress of participants. Next, the Internet, with its ability to transfer content with the click of a mouse, will play an increasing role in distant education. Video and audio streaming techniques will allow the deployment of content previously shackled to a CD-ROM platform. CD-ROM interactive technology also can help in developing clinical judgment with innovative strategies, such as Objective-Based Clinical Competency Evaluation Scenarios. Telecommunications will fuse the components of a coordinated distant learning strategy. Also, telecommunications will allow the availability of new training capabilities in the form of teleproctoring and telementoring to hospitals, no matter what their size or location. All of these components combined enable the realization of a continuing education program in minimally invasive surgery that is readily available to hospitals worldwide. Last, institutions, resident training programs, and individual surgeons must commit the time to partake in these cutting-edge programs for challenges facing us to be completely eliminated. A high priority must be placed on the resolution of these issues.

An overview of videostreaming on the Internet and its application to surgical education.

The Information Age has endowed mankind with a wealth of new technologies. Applications of these technologies are being developed to facilitate content exchange between individuals and institutions. Internet streaming is an exciting new technology that allows multimedia content to be stored and sent over the Internet, and medical educators are challenged to harness the potential of streaming for educational enhancement. This article helps to define streaming, examining its potential for surgical education.