Relationship between blood remifentanil concentration and stress hormone levels during pneumoperitoneum in patients undergoing laparoscopic cholecystectomy

The effect of remifentanil on stress response to surgery is unclear. However, there are not clinical studies investigating the relationship between blood remifentanil concentrations and stress hormones. Therefore, the aim of the present study was to assess the association between blood remifentanil concentrations measured after pneumoperitoneum and cortisol (CORT) or prolactin (PRL) ratio (intraoperative/preoperative value), in patients undergoing laparoscopic cholecystectom

Results from an ethnographically-informed study in the context of test driven development

Background: Test-driven development (TDD) is an iterative software development technique where unit tests are defined before production code. Previous studies fail to analyze the values, beliefs, and assumptions that inform and shape TDD. Aim: We designed and conducted a qualitative study to understand the values, beliefs, and assumptions of TDD. In particular, we sought to understand how novice and professional software developers, arranged in pairs (a driver and a pointer), perceive and apply TDD. Method: 14 novice software developers, i.e., graduate students in Computer Science at the University of Basilicata, and six professional software developers (with one to 10 years work experience) participated in our ethnographicallyinformed study. We asked the participants to implement a new feature for an existing software written in Java. We immersed ourselves in the context of the study, and collected data by means of contemporaneous field notes, audio recordings, and other artifacts. Results: A number of insights emerge from our analysis of the collected data, the main ones being: (i) refactoring (one of the phases of TDD) is not performed as often as the process requires and it is considered less important than other phases, (ii) the most important phase is implementation, (iii) unit tests are almost never up-to-date, (iv) participants first build a sort of mental model of the source code to be implemented and only then write test cases on the basis of this model; and (v) apart from minor differences, professional developers and students applied TDD in a similar fashion. Conclusions: Developers write quick-and-dirty production code to pass the tests and ignore refactoring.Copyright is held by the owner/auther(s)

Scalar Casimir effect between two concentric D-dimensional spheres

The Casimir energy for a massless scalar field between the closely spaced two concentric D-dimensional (for D>3) spheres is calculated by using the mode summation with contour integration in the complex plane of eigenfrequencies and the generalized Abel-Plana formula for evenly spaced eigenfrequency at large argument. The sign of the Casimir energy between closely spaced two concentric D-dimensional spheres for a massless scalar field satisfying the Dirichlet boundary conditions is strictly negative. The Casimir energy between D-1 dimensional surfaces close to each other is regarded as interesting both by itself and as the key to describing of stability of the attractive Casimir force. PACS number(s): 03.70.+k, 11.10.Kk, 11.10.Gh, 03.65.GeComment: 14 pages. arXiv admin note: substantial text overlap with arXiv:1207.418

Summary of Travel Trends: 2017 National Household Travel Survey

DTFH6114F00113The 2017 National Household Travel Survey (NHTS) provides an inventory of daily travel in the US and its major Census Divisions and add-on areas. It is the only source of national-level statistics on personal travel in the US. The survey series (conducted since 1969) includes demographic data on households, people, vehicles, and detailed information on daily travel by all modes of transportation and for all purposes. NHTS survey data are collected from a sample of households and expanded to provide estimates of trips and miles of travel by travel mode, trip purpose, and other important attributes. When combined with historical data from the earlier surveys (1969, 1977, 1983, 1990, and 1995 NPTS and the 2001 NHTS, 2009 NHTS, and 2017 NHTS) these data serve as a rich source of information on the trends in travel over time. This report summarizes trends in household and personal travel patterns, including information on changes to the household-based vehicle fleet and commuting patterns. The report begins with a summary of the changes in the population, demographics, and related travel. Next, travel trends are examined at the household level, including differences between different areas of the US and by household income, for example. Next, changes in travel are summarized at the person-level, including trips by purpose and miles of travel by age and sex. Following sections detail changes in vehicle availability and usage, commute travel patterns, temporal distribution, and the travel of special populations. The 2017 NHTS was conducted with major changes in sampling strategy (an address-based sample compared to previous land-line random-digit sample) and methodology (Web-based self-reports compared to previous computer-aided interviewing). These and other critical changes are summarized here in Appendix A and in the data documentation at https://nhts.ornl.gov/. Researchers and data users are cautioned to do their best to assess how the change in methods may affect their estimates and to caution their readers about these critical changes in the data series

An external replication on the effects of test-driven development using a multi-site blind analysis approach

Context: Test-driven development (TDD) is an agile practice claimed to improve the quality of a software product, as well as the productivity of its developers. A previous study (i.e., baseline experiment) at the University of Oulu (Finland) compared TDD to a test-last development (TLD) approach through a randomized controlled trial. The results failed to support the claims. Goal: We want to validate the original study results by replicating it at the University of Basilicata (Italy), using a different design. Method: We replicated the baseline experiment, using a crossover design, with 21 graduate students. We kept the settings and context as close as possible to the baseline experiment. In order to limit researchers bias, we involved two other sites (UPM, Spain, and Brunel, UK) to conduct blind analysis of the data. Results: The Kruskal-Wallis tests did not show any significant difference between TDD and TLD in terms of testing effort (p-value = .27), external code quality (p-value = .82), and developers' productivity (p-value = .83). Nevertheless, our data revealed a difference based on the order in which TDD and TLD were applied, though no carry over effect. Conclusions: We verify the baseline study results, yet our results raises concerns regarding the selection of experimental objects, particularly with respect to their interaction with the order in which of treatments are applied. We recommend future studies to survey the tasks used in experiments evaluating TDD. Finally, to lower the cost of replication studies and reduce researchers' bias, we encourage other research groups to adopt similar multi-site blind analysis approach described in this paper.This research is supported in part by the Academy of Finland Project 278354

Students’ and Professionals’ Perceptions of Test-driven Development: A Focus Group Study

We have conducted a qualitative investigation on test-driven development (TDD) with focus groups to develop insights on the opinions of developers using TDD regarding the unintuitive process involved, its claimed effects, as well as the context factors that can facilitate (or hinder) its application. In particular, we conducted two focus group sessions: one with professionals and another with Master students in Computer Science. We used thematic analysis template (TAT) method for identifying patterns, themes, and interpretations in gathered data. We obtained a number of results that can be summarized as follows: (i) applying TDD without knowing advanced unit testing techniques can be difficult; (ii) refactoring (one of the phases of TDD) is not done as often as the process requires; (iii) there is a need for live feedback to let developers understand if TDD is being applied correctly; and (iv) the usefulness of TDD hinges on task and domain to which it is applied to

Results of the fifth international spectroradiometer comparison for improved solar spectral irradiance measurements and related impact on reference solar cell calibration

This paper reports on the results of the fifth spectral irradiance measurement intercomparison and the impact these results have on the spread of spectral mismatch calculations in the outdoor characterization of reference solar cell and photovoltaic (PV) devices. Ten laboratories and commercial partners with their own instruments were involved in the comparison. Solar spectral irradiance in clear sky condition was measured with both fast fixed and slow rotating grating spectroradiometers. This paper describes the intercomparison campaign, describes different statistical analysis used on acquired data, reports on the results, and analyzes the impact these results would have on the primary calibration of a c-Si PV reference cell under natural sunlight

Non-commutative Corrections in Spectral Matrix Gravity

We study a non-commutative deformation of general relativity based on spectral invariants of a partial differential operator acting on sections of a vector bundle over a smooth manifold. We compute the first non-commutative corrections to Einstein equations in the weak deformation limit and analyze the spectrum of the theory. Related topics are discussed as well.Comment: 32 Pages, LaTex. Some nonessential typos in intermediate calculations in sect. 3 and 4 are corrected. The final results are the sam