Study of the human liver by ultrasound examination to search for variations of venous anatomy.

Introduction: Knowledge about venous patterns (especially portal and hepatic venous) and their variations are extremely crucial for liver transplantation and other surgical procedures on liver. Studies have been done at national or international level on variations of hepatic venous patterns by CT or MRI or by dissection on cadaveric liver. No definitive or authentic study on this topic could be noted in electronic and print media, as well as in standard textbook. Considering low cost and noninvasive nature, we utilized ultrasonography to bridge this lacuna. Aim: To estimate prevalence and types of anatomical variations of hepatic venous system and to determine association of among variations. Materials and methods: It is an observational cross-sectional study where ultrasonographic evaluation of hepatic venous pattern on adult population of either sex (consecutive sampling) without any major liver disorders was done in RG Kar Medical College and data were analyzed with appropriate statistical procedures. Results: Normal hepatic venous pattern along with normal portal venous pattern is much higher in our study, which is a unique finding. The proportion of normal portal venous pattern is more in extra hepatic bifurcation group. Variations of portal vein and normal hepatic venous pattern are more in case of intrahepatic bifurcation of portal venous branching group. Overall presence of intrahepatic bifurcation of portal vein is significantly higher than extrahepatic bifurcation. Conclusions: This study provides an updated database for the prevalence and distribution of anatomic variations of the hepatic venous and portal venous system.

Principles and biological concepts of heredity before Mendel

The knowledge of the history of a subject stimulates understanding. As we study how other people have made scientific breakthroughs, we develop the breadth of imagination that would inspire us to make new discoveries of our own. This perspective certainly applies to the teaching of genetics as hallmarked by the pea experiments of Mendel. Common questions students have in reading Mendel’s paper for the first time is how it compares to other botanical, agricultural, and biological texts from the early and mid-nineteenth centuries; and, more precisely, how Mendel’s approach to, and terminology for debating, topics of heredity compare to those of his contemporaries? Unfortunately, textbooks are often unavailing in answering such questions. It is very common to find an introduction about heredity in genetic textbooks covering Mendel without mentions of preceding breeding experiments carried out in his alma mater. This does not help students to understand how Mendel came to ask the questions he did, why he did, or why he planned his pea studies the way he did. Furthermore, the standard textbook “sketch” of genetics does not allow students to consider how discoveries could have been framed and inspired so differently in various parts of the world within a single historical time. In our review we provide an extended overview bridging this gap by showing how different streams of ideas lead to the eventual foundation of particulate inheritance as a scientific discipline. We close our narrative with investigations on the origins of animal and plant breeding in Central Europe prior to Mendel in Kőszeg and Brno, where vigorous debates touched on basic issues of heredity from the early eighteenth-century eventually reaching a pinnacle coining the basic questions: What is inherited and how is it passed on from one generation to another?

Derivation of the stationary fluorescence spectrum formula for molecular systems from the perspective of quantum electrodynamics

Numerical simulations of stationary fluorescence spectra of molecular systems usually rely on the relation between the photon emission rate and the system’s dipole–dipole correlation function. However, research papers usually take this relation for granted, and standard textbook expositions of the theory of fluorescence spectra also tend to leave out this important relation. In order to help researchers with less theoretical training gain a deeper understanding of the emission process, we perform a step-by-step derivation of the expression for the fluorescence spectrum, focusing on rigorous mathematical treatment and the underlying physical content. Right from the start, we employ quantum description of the electromagnetic field, which provides a clear picture of emission that goes beyond the phenomenological treatment in terms of the Einstein A coefficient. Having obtained the final expression, we discuss the relation of the latter to the present level of theory by studying a simple two-level system. From the technical perspective, the present work also aims at familiarizing the reader with the density matrix formalism and with the application of the double-sided Feynman diagrams.

Comparing Traditional and Augmented Reality Training for Identifying Critical Symptoms for Diagnosing Airway Obstruction Cases: A Pilot Study

Recent developments in the portability, flexibility, and affordability of augmented reality technology allow it to address some limitations of current medical training. This pilot study aims to determine whether augmented reality can enhance the detection and identification of subtle cues used to make accurate medical diagnoses. We randomly assigned five participants to a control group, where they received diagnostic training by reading a standard textbook, and an experimental group, where they received diagnostic training by a combination of reading a standard textbook and augmented reality-based training. All participants were tested with a tension pneumothorax scenario, where they listed symptoms and made a diagnosis. We recorded the time until a final diagnosis was made and categorized the diagnosis and symptoms as accurate or inaccurate. A two-tailed t-test was used to assess differences between groups. The experimental group correctly identified more symptoms than the control group (average 12 vs. 5). These results indicate the potential of AR-based training to enhance detection and identification of cues in medical diagnostics.

The myth of visual “depth cues” II. “Occlusion”

It is standard textbook practice to refer to “occlusion” as one of the so-called a depth-cues. However, perceived occluding relationships are a consequence of the perceptual organization of the retinal point stimulation – which contains no occluded surfaces. The perception of “occlusion” always involves amodal completion of areas perceived as partially occluded. Shapes, occlusions, and relative depth relationships are all descriptions of the percept. To treat one aspect of this percept as prior to other aspects is a logical fallacy linked to a failure to distinguish between the percept and the real world, and to a preference for adopting simple, pseudo-explanations of perceptual phenomena instead of tackling the difficult problems entailed in explaining perceptual organization.

Functional Correctness of C Implementations of Dijkstra’s, Kruskal’s, and Prim’s Algorithms

We develop machine-checked verifications of the full functional correctness of C implementations of the eponymous graph algorithms of Dijkstra, Kruskal, and Prim. We extend Wang et al.’s CertiGraph platform to reason about labels on edges, undirected graphs, and common spatial representations of edge-labeled graphs such as adjacency matrices and edge lists. We certify binary heaps, including Floyd’s bottom-up heap construction, heapsort, and increase/decrease priority.Our verifications uncover subtle overflows implicit in standard textbook code, including a nontrivial bound on edge weights necessary to execute Dijkstra’s algorithm; we show that the intuitive guess fails and provide a workable refinement. We observe that the common notion that Prim’s algorithm requires a connected graph is wrong: we verify that a standard textbook implementation of Prim’s algorithm can compute minimum spanning forests without finding components first. Our verification of Kruskal’s algorithm reasons about two graphs simultaneously: the undirected graph undergoing MSF construction, and the directed graph representing the forest inside union-find. Our binary heap verification exposes precise bounds for the heap to operate correctly, avoids a subtle overflow error, and shows how to recycle keys to avoid overflow.

HOW EFFECTIVE ARE ESL GAMES COMPARED TO TRADITIONAL LEARNING

The aim of this research was to discover the effectiveness of educational games in acquiring vocabulary and conversation skills while learning English as a second language (ESL) in Thai context. The study sought to examine how games and activities aided ESL learners in retaining vocabulary and engaging in role play activities. Educational games enable learners to acquire vocabulary and the relevant context subconsciously while they are engaged in seemingly non-academic activities. The result of using games and activities in the classroom is the creation of a playful atmosphere which makes the teaching-learning process more engaging and thus also makes the learning experience more enjoyable for both the learner and the teacher. The data was collected from six ESL classes totaling 160 learners from the SSRUIC Airline Business major. Evaluation checklist and survey questionnaires were selected as the research tools. The analysis of the data collected revealed that games could indeed accustom learners with new words and phrases and thus aid in deep-seated retention of vocabulary in a better, faster and more engaging way in comparison to memorization or standard textbook study. Games also help develop learners’ communicative abilities. Most of the learners interviewed recognized that the game-based methods have their advantages and benefits in terms of improving vocabulary and conversation skills. However, to overcome certain limitations, the researcher suggests further study in this direction.

Secondary Grammar Education in the Middle Ages

The study of language and literature had a fundamental role in medieval education, being a major subject at all levels of education. This chapter deals with medieval language teaching in Western Christendom, focusing on the core of grammatical treatises, consisting of a systematic description of the parts of speech and their syntax. From the Carolingian reform on, grammar instruction continued to be influenced by logic, and the role of literature diminished. Grammar teaching became increasingly analytical, and Donatus’s standard textbook could no longer meet the requirements of language pedagogy in the High and Later Middle Ages. Its study began to be accompanied by other short treatises, which represented new doctrines, e.g. syntactical theory, and new forms of teaching, such as parsing grammars and grammars in verse.

Utility Matters

The present-day standard textbook narrative on the history of growth theory usually takes Robert Solow’s 1956 contribution as a key starting point, which was extended by David Cass and Tjalling Koopmans in 1965 by introducing an intertemporal maximization problem that defines the saving ratio in the economy. However, the road connecting Solow to the Ramsey-Cass-Koopmans model is not so straightforward. We argue that in order to understand Koopmans’s contribution, we have to go to the activity analysis literature that started before Solow 1956 and never had him as a central reference. We stress the role played by Edmond Malinvaud, with whom Koopmans interacted closely, and take his travel from the French milieu of mathematical economics to the Cowles Commission in 1950-51 and back to France as a guiding line. The rise of turnpike theory in the end of the 1950s generated a debate on the choice criteria of growth programs, opposing the productive efficiency typical of these models to the utilitarian approach supported by Malinvaud and Koopmans. The Vatican Conference of 1963, where Koopmans presented a first version of his 1965 model, was embedded in this debate. We argue that Malinvaud’s (and Koopmans’s) contributions were crucial to steer the activity analysis literature toward a utilitarian analysis of growth paths.

Discounted Cash Flow Methods in Lease versus Purchase Analysis—A Technical Note

The earlier framework uses the before-tax cost of debt as the discount rate in valuation of lease contracts for the reason that such framework explicitly includes the interest tax credits as a component of each period’s cash flows. The short-cut or modern standard textbook approaches use after-tax cost of debt as the discount rate for the reason that it ignores the interest tax credits. Some existing literatures state the two approaches are equivalent without exploring the reasons analytically. This note provides a mathematical demonstration showing, the two approaches are not equivalent accompanied by numerical examples.