bluuebunny/crossref_metadata_2025 huggingface dataset:
Understanding physical phenomena through simulation exercises
Authors: Saastamoinen K , Rissanen A
Published: August 2019

Traditional lectures and exercises are good for gaining basic knowledge in STEM (Science, Technology, Engineering and Mathematics). If feasible, motivational and deeper learning experiences like laboratory - or work life-related field experimentation are included in studying levels, more concrete learning experiences can be reached. At the National Defence University (NDU), the theoretical part of master’s level studies in STEM relies on earlier basic studies. In order to promote practical skills, a specific simulation and modelling course is aimed at learning how real-world artifacts or models work, how to acquire data, how to visualise the acquired data, and to develop one’s understanding trough simulations. This course ends with a group work, where participating students are asked to produce a working simulation model either from the given list or from their professional context. This study describes two sample cases: The first one is a flight simulator that includes a lot of physics and physical phenomena. The second one illustrates time dependence and statistical nature of targeting. The course’s success is estimated from reports and the feedback given by the students. Observations on motivation and learning goals are included. For military officers learning is practically oriented, while in natural sciences learning is theoretically oriented. In both cases simulation is a natural “bridge” in between theory and practice.
Teaching and learning introductory electrostatics - conformity with nomenclature conventions
Authors: O’Sullivan C
Published: August 2019

The treatment of electric flux in most textbooks on introductory physics, at least in the English language, differs radically from the definitions prescribed by the statutory and intergovernmental organizations (CGPM, BIPM, IUPAP, IUPAC, NIST, etc). The approach also conflicts with the treatment of the topic in many electrical engineering texts. Furthermore, it is at variance with the standard treatment of matter elsewhere in the curriculum (e.g., mechanical or thermal properties). Historical reasons for this discrepancy are investigated and it is suggested that resolving this conflict would be beneficial to the teaching and learning of this and related topics.
Ferrofluids in secondary schools through an interactive stand
Authors: Caroaie O V , Caltun O F
Published: August 2019

A central theme of the discussion about education in Europe is linked to improving the quality and relevance of skills and competences that educational system beneficiaries form during their training. To perform a proper and coherent analysis on the introduction of informations about ferrofluids in the national curriculum a sociological study was conducted in several schools in the city Bârlad, Romania. Through an interactive exhibition stand, pupils were able to maneuver a ferrofluid with a magnet. The stand was arranged such as to allow easy access for handling the ferrofluid and for reading the informations displayed on its walls.
Sources of motivation of high school students for participation in physics competitions
Authors: Kolář K
Published: August 2019

This article studies motives on why high school students participate in physics competitions in the form of a case study (with qualitative and quantitative elements) focused on one contest. We bring a brief insight into primary motivations for their participation and how it is changing later. The pinpoint of our study is that it is hard to address new participants these days. Their most often motivation for starting in the competition is to get better in physics, general interest in physics and interest in solving challenging tasks. For those who continue in participation – they usually want to get even better in physics. That’s because participants often realise that they are not as good as they thought. A motivation which is getting stronger is also to get an invitation to an educational camp. We also briefly discuss possible demotivational factors.
Understanding acceleration: An interplay between different mathematics and physics representations
Authors: Pendrill A-M
Published: August 2019

Acceleration is often viewed as abstract – but when a person accelerates, e.g. in a car or on swings, trampolines, carousels or rollercoasters, the force required for the acceleration is felt throughout the body. If acceleration is introduced as force divided by mass rather than as a second derivative of displacement, the concept can be made accessible to much younger learners, such as 10-year olds taking part in supervised visits to an amusement park or playground. The force required for acceleration can be measured e.g. using smartphone sensors. The forces can also be illustrated in demonstrations that complement photos and video analysis. For a teacher this creates opportunities to discuss challenging concepts of force and motion, in enjoyable authentic situations.
Research and Development of Distribution Automation Terminal Based on IEC61850
Authors: Zhang Peng , Xu Peng , Wang Yize , Wang Wei
Published: August 2019

Distribution automation system is an important means to improve the reliability and quality of power supply, expand power supply capacity, and realize efficient and economic operation of distribution network. However, the existing problems are: low online rate of distribution terminal, low data utilization rate, low success rate of remote control of distribution automation system, and great difficulty in operation and maintenance. This paper studies and develops a hardware development platform of distribution terminal based on high-speed bus interaction technology of distribution terminal. The software development platform based on IEC61850 information model and modeling technology can improve the level of distribution automation and application effect.
Modeling and Diagnosis of Joints in High Voltage Electrical Transmission Lines
Authors: Bindi M. , Grasso F. , Luchetta A. , Manetti S. , Piccirilli M.C.
Published: August 2019

In this paper a new method is developed and described, aimed at the modeling and diagnosis of the joints connecting the ends of two cables on a high voltage electricity pylon. Identifying the anomalous joint behaviour through the line frequency response analysis is the first objective of the work. For this reason, it is necessary to model the whole overhead line with a lumped circuit and studying the joint electrical parameter variation. The problem is approached in multiple steps: modelling, testability analysis of the model, optimal frequency selection, identification of the possible failures. Some simulated cases are included in order to show the potentialities of the method.
A Calculation Model for Typical Data Center Cooling System
Authors: Huang Jianwen , Chen Cheng , Guo Guiyang , Zhang Zhang , Li Zhen
Published: August 2019

This paper has established a typical calculation model for typical data center cooling system, including the inside room CRAC system, outside free cooling usage system and chiller. The aim of establishing such method is to calculate the power consumption of the data center and to guide the work of energy conservation. The results show that, higher inside room temperature, lower water mass flow rate and lower outside air temperature lead to lower PUE.
Optimization of Drilling Parameters with Aid of Real Time Data for Buzargan Oil Field
Authors: Hazem Hassan Khalid , Abdul Hussien Hassan A. H.
Published: August 2019

This paper showed how real-time data that obtained during drilling operation can be used for optimizing drilling parameter such as weight on bit (WOB), and rotary speed (RPM) in term of drilling cost per foot. The real-time data that obtained from mud logging unit included the rate of penetration (ROP), WOB, RPM, depth …. etc.

In this work, the real-time data obtained from Buzurgan oil well (BU-50) were used for drilling optimization. Rock strength for each drilling foot of section obtained from a sonic log, using SPSS (Statistics) software to calculate it correction factors a,b, and c for Mishrif formation and apply nonlinear regression method after that make drill behind for validation purpose. Finally, the optimal drilling parameters were estimated with the cost model.

Based on the results obtained, a good agreement achieved between results of rate of penetration that obtained from drilling model and actual penetration rate along the drilling section. Also, cost analysis shows that the optimal weight on bit and rotary speed for drilling that section are 18 klb and 116 rpm respectively which achieves a minimum cost per foot.
Zn/HY-Zeolite as a Catalyst for Upgrading Iraqi Heavy Crude Oil Using Aquathermolysis Method
Authors: Saeed Amani Q. , Hamadi Adel S. , Sherhan Bashir Y.
Published: August 2019

Upgrading heavy crude oil from East of Baghdad oilfield using a high pressure reactor with steam supplied and toluene as hydrogen donor has been investigated through aquathermolysis process. Synthesized Zn/HY Zeolite, which is characterized by XRD, SEM, EDX, FT-IR, BET-surface area and pore volume has been employed as a bi-functional catalyst. Statistical design of experiment (DOE) is also applying in determine the optimum operating conditions of aquathermolysis reaction under different temperatures, time and weight percentage of catalyst with the targeted response being the viscosity after upgrading. The extent of upgrading might be established through various analyses of the initial unconventional oil and final produced crude oil. These were included the measurements of oil density, API gravity, oil viscosity, flash point, pour point, sulfur content and yield of light and intermediate fractions. The results show that the optimum operating conditions are found at 0.25 wt% of catalyst, 231.25°C and 30 h reaction time. The experimental data under these conditions has confirmed that the viscosity and sulfur are decreased by 67.25% and 55.58% respectively, whilst the API has increased up to 24.5. The response surface regression model equation in coded unit for viscosity reduction percentage has been established.
Effect of Ce-promotion on iron catalysts activity through the synthesis of liquid fuels by the Fischer-Tropsch process
Authors: AL-Zuhairi F K , Kadhim W A
Published: August 2019

The main objective of this work is studying the effect of cerium promotion and reaction temperature on the catalysts activity and product selectivity, the iron-based catalysts utilized in this study were prepared by impregnation methods and characterized via temperature programmed reduction (TPR) and N2 adsorption-desorption isotherms. Reaction experiments were accomplished in a stainless steel fixed bed reactor. The reaction experiments for unpromoted and promoted catalysts were done at pressure 20 bar, space velocity 1400 h−1, H2/CO=2 and different reaction temperature (250, 275, 300 and 325 ºC). The results have shown the addition of promoter to iron-based catalyst enhanced the reducibility of Fe2O3 through a shift down in reduction temperature, furthermore, for both catalysts, conversion of carbon monoxide (CO) and selectivities of undesired products (CO2, CH4, and C2-C4) were found to be increased whereas the selectivity of desired products (C5+) was decreased with increasing in a reaction temperature from 55.87 to 35.65% and from 73.03 to 61.59 % for unpromoted and Ce-promoted catalysts respectively. A higher selectivity for high molecules weight hydrocarbons was about 73.03% detected at lower reaction temperature (250 ˚C) when a promotion catalyst was used.
Tracking boil off gas generation into liquefied natural gas supply chain using HYSYS simulator
Authors: Naji S Z , Abd A A , Hashim A S
Published: August 2019

Liquefied natural gas (LNG) is becoming one of the prominent clean energy sources with its abundance, high potential energy, and low emission and price. Unavoidable reality is that boil off gas (BOG) generates, because of low temperature of LNG, about -162.5 °C at 101.3 kPa for storage and transportation of liquefied natural gas. As natural gas productions increasing globally, BOG and handling problems become serious critical subject in both economic and environment regulations. In this work, liquefied natural gas storage facilities and loading facilities are simulated to investigate the generated BOG by calculating the heat leaks through cargo tank, pipelines, storage tank, and the generated heat by equipment’s. Later, boil off gas rates are estimated for each sector into LNG supply chain with different operational conditions, parameters and voyage time. Factors that affect BOG such as operation temperatures and pressures, methane content, and nitrogen content are presented. Current study would help to properly store and transport LNG to minimize the venting of BOG into supply chain, and thus reducing greenhouse emissions, save energy, and reducing waste of natural gas.
Syngas formation by dry and steam reforming of methane using microwave plasma technology
Authors: Majd Alawi Nabil , Hung Pham Gia , Barifcani Ahmed , Hoang Nguyen Minh , Liu Shaomin
Published: August 2019

The combined dry and steam reforming of methane at atmospheric pressure was experimentally studied by using microwave plasma technology. The effect of the process parameters such as total feed gas flow rate, steam concentration and input microwave power on the synthesis gas H2/CO ratio was investigated using a commercial microwave reactor system. In order to minimise the carbon formation and plasma instability, the concentration of methane and carbon dioxide in nitrogen plasma were kept at a low level in this study. The long-term test results show that at the flow rate of 0.2 L min−1, 0.4 L min−1 and 1.5 L min−1 for CH4, CO2 and N2 respectively, the carbon formation was not detectable at the input power of 700 W. This reaction condition offers an opportunity to study the effect of adding water to the feed on the syngas ratio H2/CO. The test results show that a higher CH4 conversion (82.74%), H2 selectivity (98.79%) and yield (81.73%) were achieved compared with those of the dry reforming at the same operating conditions. With the steam addition, the desired H2/CO ratio for the Fischer-Tropsch synthesis process can be reached.
Application of Geophysical Logs to Estimate the Source Rock Quantity of Ratawi Formation, Southern Iraq: A Comparison Study
Authors: Idan Rami M. , Faisal Rasha Fawzi
Published: August 2019

Quantitative detection of the parameters of source rock that targeted Ratawi Formation in the south of Iraq is achieved via the Geophysical log data, precisely the resistivity, porosity, and gamma-ray log of the well X in the northern part of Mesopotamian basin, which is so called Euphrates subzone. Total organic carbon and source rock productivity is detected by mathematically interpreting of the log parameters and that lead to assigning and identification of the content of organic matter and source rock intervals. The responses of log curvatures are relevant to the rise of total organic carbon, which can be identified via logs indicators. Thereby, the organic carbon can be expected with a surge in values of sonic log, gamma-ray values, neutron or total porosity log, and resistivity as well as a decrease in the density log. The adoption of sonic/resistivity overlay technique for the determination of total organic carbon content has indicated the likely lithology of the intervals of interest where the logs initially could indicate the lithology. As such, high organic carbon content is significant to environments that have relatively low energy.
Low salinity water flooding in carbonate reservoirs – dissolution effect
Authors: Hadi Y A , Hussain F , Othman F
Published: August 2019

One of the most significant research subjects in the industry of oil is the low salinity water injection techniques (LSWI). This is because there are possible benefits of raising recovery in oil as opposed to the conventional injection of seawater. Recent research has been done to find out the causes of less salinity with the injection of water in carbonated rocks presented significant findings. The primary mechanisms that are thought to lower salinity water injection are carbonate rocks dissolution, fines migration and alteration of wettability to more water wet. However, many researchers have elected to oppose the mechanism of dissolution and instead attributed high recovery of oil to be the primary wettability modification mechanism. Additionally, previous researchers provided no evidence characterizing about the rock and fluids produced in a detailed manner. This research work provides a detailed description of the underlying mechanisms, the core flood laboratory and the spontaneous imbibition in carbonate rocks. In the experiment, we carried out a series of steps using a limestone core with low permeability. This core was obtained from a nearby oilfield in Iraq and used it to study how dissolution and fines migration mechanisms take place. Moreover, in the process of carrying out the experiment and before its starting, SEM imaging analysis was used. In this case, as we carried out the experiment, we had to inject two-phase flow of sea water (SW), de-ionized water (DW) as well as soltrol-130. This was done in a sequential manner at 50 °C as well as 0.02 ml per minute. As the experiment progressed, the concentration of ions and pH value of the extracted water were measured in a continuous manner. The results obtained indicate that the rate of change in concentration of Ca2+ ions is directly proportional to the effluent pH value. By just balancing the mass, we were able to easily see the rate at which limestone dissolved as the experiment progressed. The maximum increase in pH was registered when fresh water was injected (pH=9.2). An increase in pH value can have a positive effect on altering wettability in that it can increase the alkalinity of flood water. To notice fines migration, the Scanning Electron Microscope (SEM) and Energy Dispersive Spectroscopy (EDS) are used to scan the images of the inlet and outlet of the core plugs after completion the experiment. This method can indicate that dissolution can induce fines dislodgement for the surface of the rock. The two mechanisms of fine migration and carbonate rock dissolution can significantly increase recovery of oil and at the same time inject water low in salinity.
Application of streamlines for improved waterflood management of iraqi’s reservoir
Authors: al-musawi S , keshavarz moraveji M , Adnan M , Jawad M
Published: August 2019

In this paper, Using the unique advantages of streamline based (SL) flow simulation, for the first time, we have attempted to simulate waterflood strategies in Buzrgan oil field in southern Iraq and to optimize it. Therefore, in this paper the streamlines are really significant that:

• The numerical calculation of the produced and injection fluid at any given time is possible for each pair of wells.

• Fux pattern maps represent the significant information of the streamlines.

• The runtime in the simulation of the (SL) is much less than finite-difference (FD).

Using this (WAF’s), it is possible to calculate the efficiency of injected wells as the proportion of injected water to the oil delivered at balance wells. With injectedefficiencies (IE) known over the field for every injector, water can be reallocated from low-efficiency to high-efficiency wells, in this way computing the assemblyfor each barrel of water injected, resulting in more sweeping and significant optimization. In addition to this, the IE chart has been given obvious visual of the reservoir management such as (eg, the changes of the wells with low IE to the injection wells.
3D geological model of Nahr Umr/Ratawi oil field in Basra
Authors: Rashad Jemeel Mohammed , Lazim Samahr A. , Sameera  , Hamdullah M.
Published: August 2019

The study includes building a 3-D geological model, which involves get the Petrophysical properties as (porosity, permeability and water saturation). Effective Porosity, water saturation results from log interpretation process and permeability from special correlation using core data and log data. Clay volume can be calculated by six ways using IP software v3.5 the best way was by using gamma Ray. Also, Water Resistivity, flushed zone saturation and bulk volume analysis determined through geological study. Lithology determined in several ways using M-N matrix Identification, Density-Neutron and Sonic-Neutron cross plots. The cut off values are determined by Using EHC (Equivalent Hydraulic Unit) method. The full grid of the model was 454308 cells. Layering of units depend on the importance of these units and scale up had done using several methods depend on property (Arithmetic for porosity and water saturation and geometric for permeability). Petrophysical properties distributed using Gaussian statistical approach. Original oil in place calculated for Nahr Umr which equal to 460 m3.
Skin and Reservoir Pressure Profiling Utilizing Production Logging
Authors: Baker H A , Salih I S
Published: August 2019

Production Log is a key log that directly define the facies and layers behavior. The PLT measures the inflow zone thickness and the flow rate of each phase which is directly function of facies properties in terms of deliverability. On the basis of pseudo steady state flow regime (which is the dominant phase of production during PLT log operations) a mathematical relationship developed to determine skin and reservoir pressure per each inflow zone with reasonable error.
Study of multi-stage centrifugal pump guide vanes in a package of hydrodynamic simulating STAR CCM+
Authors: Abramov K
Published: August 2019

For multistage centrifugal pumps, one of the main components is the guide vane. A rather important task for the guide vane is compliance with the requirements of the technical specification. It is equally important technologically correct to produce a guide vane. The manufacture of such parts is a time consuming process. To avoid a number of difficulties, this article explores the two most frequently used guide vanes of hydrodynamic simulating tools.
The evaluation of the effect of gas content on the characteristics of a Centrifugal Pump
Authors: Saprykina M , Lomakin V
Published: August 2019

The effect of gas content on the changing ofhead of a centrifugal pump isresearched. The method of numerical hydrodynamic modeling is used for solving this problem. The using mathematical model is described. The results of the simulation of fluid flow,which are depended on the air content, are presented. The data on the changingof head and the termination of its work are obtained.
Mathematical representation of pressure regulator with variable characteristic
Authors: Kolodin I , Ryabinin M
Published: August 2019

One of major pressure regulator features is its static characteristic. It is necessary to choose parameters fulfilling static characteristic requirements while designing a regulator. The article observes possible requirements imposed on static characteristic and shows mathematical description of balance of pressure regulator with variable characteristic. Static characteristics are plotted for some of parameters being varied and others fixed. Influence of parameters is analyzed on the base of obtained data and recommendations for its choosing are given.
Definition of positive displacement pump output regulation mechanism parameters with providing of constant flow capacity in output
Authors: Barmin S , Nikitin O
Published: August 2019

This paper surveys mechanism of supply regulation for axial-piston pump with adjustable-angle swash plate operating with constant power. The mechanism includes a piston, whose working space is connected to delivery port, regulation unit and two springs. Least square method and successive approximations method are used to calculate parameters of the mechanism: cut-in pressure level for the second spring and springs stiffness. Regulation effectiveness is estimated by calculation of relative error of power delivered.
The multifaceted role of material production in society
Authors: Mukhin A , Ganina G , Mozgin S , Ostrovskiy Yu , Yakovleva A
Published: August 2019

The paper considers a new approach to substantiating the role and place of material production in a person’s life. It is shown that material production performs not only the function of satisfying the material needs of a person but is also the source for the development of spiritual production. The evidence base of such allegations is given. The paper may be useful to specialists in the field of production management and development, as well as to employees of educational institutions in the field of technology, production organization, economics, and sociology.
Comparative analysis of the use of the spiral and bladed stators in a compact high-speed centrifugal pump with hydrodynamic modeling methods
Authors: Martynyuk A , Petrov A , Kuleshova M
Published: August 2019

The relevance of improving pumps used in thermal stabilization systems and increasing their service life by reducing the radial forces on the rotor of the impeller is considered. The influence of the guide vane on the characteristics of a compact high-speed centrifugal pump is investigated. With the help of hydrodynamic modeling in STAR CCM + software package, the values of head, efficiency, radial force and power for two pumps were obtained. A comparison of the obtained characteristics of a pump with a spiral and a bladed stator was carried. The advantages and disadvantages of the guide vane are determined and recommendations for improving its characteristics are given.
Investigation of hermetic low-speed pumps performance when operating on highly viscous liquids
Authors: Petrov A , Morozov A , Kuleshova M
Published: August 2019

Annotation

During the operation of hermetic low-speed vane pumps in a wide range of viscosities of the working fluid, their characteristics change significantly. Experimental dependencies of the effect of viscosity on these characteristics for hermetic vane pumps do not exist. To determine these changes, 3D-models of the flow parts for various pumps are designed. By means of hydrodynamic modeling characteristics for each model are calculated when operating on highly viscous liquids. The results obtained are summarized in the form of relative head ratio and relative efficiency, which determine the performance characteristics of a hermetic pump for various operating modes. A comparison of the results with existing ones is carried.
Left ventricular assist devices of a new generation
Authors: Grishakov V , Shein S , Lomakin V
Published: August 2019

The most competitive left ventricular assist devices (LVAD) in the world were identified in this article. 3D models of two samples were constructed for pumping blood based on existing pumps. The models were imported into the software package, where the flow of blood through these models was modeled. For this, a computational grid was constructed. According to the results of calculations, the main characteristics of the samples were obtained, as well as pictures of the distribution of velocities and pressures in the flow part. The calculation used a number of basic hydraulic equations that form a mathematical model.
Methods for Dealing With Missing Covariate Data in Epigenome-Wide Association Studies
Authors: Mills Harriet L , Heron Jon , Relton Caroline , Suderman Matt , Tilling Kate
Published: August 2019

Multiple imputation (MI) is a well-established method for dealing with missing data. MI is computationally intensive when imputing missing covariates with high-dimensional outcome data (e.g., DNA methylation data in epigenome-wide association studies (EWAS)), because every outcome variable must be included in the imputation model to avoid biasing associations towards the null. Instead, EWAS analyses are reduced to only complete cases, limiting statistical power and potentially causing bias. We used simulations to compare 5 MI methods for high-dimensional data under 2 missingness mechanisms. All imputation methods had increased power over complete-case (C-C) analyses. Imputing missing values separately for each variable was computationally inefficient, but dividing sites at random into evenly sized bins improved efficiency and gave low bias. Methods imputing solely using subsets of sites identified by the C-C analysis suffered from bias towards the null. However, if these subsets were added into random bins of sites, this bias was reduced. The optimal methods were applied to an EWAS with missingness in covariates. All methods identified additional sites over the C-C analysis, and many of these sites had been replicated in other studies. These methods are also applicable to other high-dimensional data sets, including the rapidly expanding area of “-omics” studies.
neoepiscopeimproves neoepitope prediction with multivariant phasing
Authors: Wood Mary A , Nguyen Austin , Struck Adam J , Ellrott Kyle , Nellore Abhinav , Thompson Reid F
Published: August 2019

Motivation

The vast majority of tools for neoepitope prediction from DNA sequencing of complementary tumor and normal patient samples do not consider germline context or the potential for the co-occurrence of two or more somatic variants on the same mRNA transcript. Without consideration of these phenomena, existing approaches are likely to produce both false-positive and false-negative results, resulting in an inaccurate and incomplete picture of the cancer neoepitope landscape. We developed neoepiscope chiefly to address this issue for single nucleotide variants (SNVs) and insertions/deletions (indels).

Results

Herein, we illustrate how germline and somatic variant phasing affects neoepitope prediction across multiple datasets. We estimate that up to ∼5% of neoepitopes arising from SNVs and indels may require variant phasing for their accurate assessment. neoepiscope is performant, flexible and supports several major histocompatibility complex binding affinity prediction tools.

Availability and implementation

neoepiscope is available on GitHub at https://github.com/pdxgx/neoepiscope under the MIT license. Scripts for reproducing results described in the text are available at https://github.com/pdxgx/neoepiscope-paper under the MIT license. Additional data from this study, including summaries of variant phasing incidence and benchmarking wallclock times, are available in Supplementary Files 1, 2 and 3. Supplementary File 1 contains Supplementary Table 1, Supplementary Figures 1 and 2, and descriptions of Supplementary Tables 2–8. Supplementary File 2 contains Supplementary Tables 2–6 and 8. Supplementary File 3 contains Supplementary Table 7. Raw sequencing data used for the analyses in this manuscript are available from the Sequence Read Archive under accessions PRJNA278450, PRJNA312948, PRJNA307199, PRJNA343789, PRJNA357321, PRJNA293912, PRJNA369259, PRJNA305077, PRJNA306070, PRJNA82745 and PRJNA324705; from the European Genome-phenome Archive under accessions EGAD00001004352 and EGAD00001002731; and by direct request to the authors.

Supplementary information

Supplementary data are available at Bioinformatics online.
When acting as a reproductive barrier for sympatric speciation, hybrid sterility can only be primary
Authors: Forsdyke Donald R
Published: August 2019

Animal gametes unite to form a zygote that develops into an adult with gonads that, in turn, produce gametes. Interruption of this germinal cycle by prezygotic or postzygotic reproductive barriers can result in two cycles, each with the potential to evolve into a new species. When the speciation process is complete, members of each species are fully reproductively isolated from those of the other. During speciation a primary barrier may be supported and eventually superceded by a later-appearing secondary barrier. For those holding certain cases of prezygotic isolation to be primary (e.g. elephant cannot copulate with mouse), the onus is to show that they had not been preceded over evolutionary time by periods of postzygotic hybrid inviability (genically determined) or sterility (genically or chromosomally determined). Likewise, the onus is upon those holding cases of hybrid inviability to be primary (e.g. Dobzhansky–Muller epistatic incompatibilities) to show that they had not been preceded by periods, however brief, of hybrid sterility. The latter, when acting as a sympatric barrier causing reproductive isolation, can only be primary. In many cases, hybrid sterility may result from incompatibilities between parental chromosomes that attempt to pair during meiosis in the gonad of their offspring (Winge-Crowther-Bateson incompatibilities). While such incompatibilities have long been observed on a microscopic scale, there is growing evidence for a role of dispersed finer DNA sequence differences (i.e. in base k-mers).
The life aquatic: an association between habitat type and skin thickness in snakes
Authors: Shine Richard , Goiran Claire , Shilton Catherine , Meiri Shai , Brown Gregory P
Published: August 2019

An aquatic animal faces challenges not encountered by its terrestrial counterparts, promoting adaptive responses in multiple traits. For example, a thicker dermis might protect snakes when they are pushed against sharp objects by water currents, and might enable a snake to shed fouling organisms attached to its skin. We thus predicted that marine snakes should have thicker skin than terrestrial species, and that smaller sea snakes should have relatively thicker skin (because absolute, not relative, thickness determines vulnerability to fouling). Measurements of 192 snakes of 44 species supported those predictions. Many (but not all) sea snakes have skins 50% thicker than those of terrestrial and amphibious snake species, representing multiple independent evolutionary origins of thicker skin (in acrochordids, Laticauda sea kraits and both main clades of hydrophiine sea snakes). Marine snakes showed different allometries of skin thickness compared with their terrestrial counterparts; larger snakes had thicker skin within and among species of amphibious and terrestrial snakes, but larger aquatic snake species had thinner skin compared with smaller taxa. Interspecific variation in skin thickness was primarily due to increased collagen in the deep dermis, a physical barrier well suited to protecting against physical injury and to resisting penetration by epibionts.
Dynamic modular-level alterations of structural-functional coupling in clinically isolated syndrome
Authors: Koubiyr Ismail , Besson Pierre , Deloire Mathilde , Charre-Morin Julie , Saubusse Aurore , Tourdias Thomas , Brochet Bruno , Ruet Aurélie
Published: August 2019

Changes in both structural and functional connectivities are observed in multiple sclerosis, but little is known about how the evolution of one affects the other. Koubiyr et al. investigate the longitudinal multimodal reorganization of brain networks in the year following clinically isolated syndrome, and reveal structural-functional decoupling in several networks.
Separation of Low- Versus High-grade Crohn’s Disease-associated Small Bowel Carcinomas is Improved by Invasive Front Prognostic Marker Analysis
Authors: Arpa Giovanni , Grillo Federica , Giuffrida Paolo , Nesi Gabriella , Klersy Catherine , Mescoli Claudia , Lenti Marco Vincenzo , Lobascio Gessica , Martino Michele , Latella Giovanni , Malvi Deborah , Macciomei Maria Cristina , Fociani Paolo , Villanacci Vincenzo , Rizzo Aroldo , Ferrero Stefano , Sessa Fausto , Orlandi Augusto , Monteleone Giovanni , Biancone Livia , Cantoro Laura , Tonelli Francesco , Ciardi Antonio , Poggioli Gilberto , Rizzello Fernando , Ardizzone Sandro , Sampietro Gianluca , Solina Gaspare , Oreggia Barbara , Papi Claudio , D’Incà Renata , Vecchi Maurizio , Caprioli Flavio , Caronna Roberto , D’Errico Antonietta , Fiocca Roberto , Rugge Massimo , Corazza Gino Roberto , Luinetti Ombretta , Paulli Marco , Solcia Enrico , Di Sabatino Antonio , Vanoli Alessandro
Published: August 2019

Background and Aims

Crohn’s disease-associated small bowel carcinoma is a rare event, usually reported to have a severe prognosis. However, in previous investigations we have found a minority of cases displaying a relatively favourable behaviour, thus outlining the need to improve the histopathological prediction of Crohn’s disease-associated small bowel carcinoma prognosis.

Methods

As in recent studies on colorectal cancer, a substantial improvement in prognostic evaluations has been provided by the histological analysis of the tumour invasive front; we therefore systematically analysed the tumour budding and poorly differentiated clusters in the invasive front of 47 Crohn’s disease-associated small bowel carcinomas collected through the Small Bowel Cancer Italian Consortium.

Results

Both tumour budding and poorly differentiated cluster analyses proved highly effective in prognostic evaluation of Crohn’s disease-associated small bowel carcinomas. In addition, they retained prognostic value when combined with two other parameters, i.e. glandular histology and stage I/II, both known to predict a relatively favourable small bowel carcinoma behaviour. In particular, association of tumour budding and poorly differentiated clusters in a combined invasive front score allowed identification of a minor subset of cancers [12/47, 25%] characterised by combined invasive front low grade coupled with a glandular histology and a low stage [I or II] and showing no cancer-related death during a median follow-up of 73.5 months.

Conclusions

The improved distinction of lower- from higher-grade Crohn’s disease-associated small bowel carcinomas provided by invasive front analysis should be of potential help in choosing appropriate therapy for these rare and frequently ominous neoplasms.
Does Demanding Activation Work? A Comparative Analysis of the Effects of Unemployment Benefit Conditionality on Employment in 21 Advanced Economies, 1980–2012
Authors: Knotz Carlo Michael
Published: August 2019

Whether or not putting the unemployed under greater pressure to seek and accept jobs really helps to raise levels of employment remains a controversially discussed question. Empirical research into this question has so far focused on the micro-level whereas the macro-level effects remain unexplored. This article fills this gap, using a novel comparative dataset on the strictness of job-search and availability requirements and sanction rules for unemployment benefit claimants in 21 countries between 1980 and 2012. It is shown that requiring more active job-search and availability for a wider range of jobs does indeed lead to increased employment, while no evidence for a similar positive effect of tougher sanction rules on employment is found. The data do indicate, however, that sanction rules are themselves a product of adverse labour market conditions. Interactive estimations also suggest a negative moderating influence of tough sanction rules on the effectiveness of stricter conditions, whereas more generous unemployment insurance and assistance benefits appear to strengthen the effects of stricter conditions. Overall, the results suggest that to increase employment, the treatment of the unemployed may be demanding but should not be punitive and should include supportive elements, providing claimants with the resources they need to effectively look for work.
The Cohomological Brauer Group of a Torsion 𝔾m-Gerbe
Authors: Shin Minseon
Published: August 2019

Let $S$ be a scheme and let $\pi : \mathcal{G} \to S$ be a ${\mathbb{G}}_{m,S}$-gerbe corresponding to a torsion class $[\mathcal{G}]$ in the cohomological Brauer group ${\operatorname{Br}}^{\prime}(S)$ of $S$. We show that the cohomological Brauer group ${\operatorname{Br}}^{\prime}(\mathcal{G})$ of $\mathcal{G}$ is isomorphic to the quotient of ${\operatorname{Br}}^{\prime}(S)$ by the subgroup generated by the class $[\mathcal{G}]$. This is analogous to a theorem proved by Gabber for Brauer–Severi schemes.
Contemporary Images of Hindu Bhakti: Identity and Visuality
Authors: Holt Amy-Ruth , Pechilis Karen
Published: August 2019

Historians writing on modernity often remark on the power of the visual, appealing to Walter Benjamin's influential observation that ‘modernity under late capitalism is dominated, and haunted, by dream-images and commodified visual fetishes’ (Benjamin 1968; Levin 1993, p.23; Ramaswamy 2003, p.xiii). Yet, studies of bhakti commonly focus on the literature and biographies of the bhakti saints instead of its visual dimensions in art, material culture, and performance. In this special issue, scholars of religion and art history writing on diverse visual cultures, communities, and geographical locations under the umbrella of the contemporary era reveal two distinguishing features of bhakti. The first is bhakti's impetus to establish the artist's, devotee's, or saint's individual and communal identity that resituates today's religion. The second is bhakti's formation of emotive imagery with visual agency animated by participatory desires that inspire the creation and re-creation of imagery and performances that speak directly to the everyday. Identity and visuality, found together in contemporary bhakti imagery, shape our distinctive analysis and redirect Benjamin's original statement from postcolonial nation-building towards the vitality of devotional participation.
Part I How Section 4 Works, 3 Trickier Questions
Authors: Brian C Kalt
Published: August 2019

This chapter asks and answers several questions that Section 4 does not resolve simply with its text. The questions include: (1) Who counts as “the Cabinet?” (2) Can Congress specify a decision maker other than the Cabinet? (3) What if there is no Vice President to invoke Section 4? (4) How are written declarations (of inability and ability) transmitted to Congress? (5) Can the President and Vice President agree to end the waiting period for his return early? (6) Could the Vice President and Cabinet or Congress manipulate the process to keep the President out longer? (7) If the President wins in Congress, does he take back power immediately? (8) What role do the courts have in resolving any disputes, if any?
Part II History: Fact and Fiction, 6 Presidential Inability Since 1967
Authors: Brian C Kalt
Published: August 2019

Section 4 of the Twenty-Fifth Amendment has never been used, though it should have been used when President Reagan was shot and nearly killed in 1981. He was unconscious for hours and incapacitated for days, but his administration decided not to transfer power to Vice President Bush. Several years later, Reagan’s staff considered Section 4 more seriously, due to concerns about the President’s performance. They decided against it. Reagan did, however, invoke the Twenty-Fifth Amendment’s less exciting Section 3 prior to a planned surgery, setting a precedent followed by President George W. Bush on two occasions.
Part III Section 4 in “Practice”, 9 Tough Calls
Authors: Brian C Kalt
Published: August 2019

The hypothetical situations in this chapter raise more difficult issues. Here, the President might suffer from dementia or a stroke but be unaware of her lost faculties. Mental illness might cause a president to become unable to discharge his powers and duties, but could be difficult to diagnose. If the President is able to contest a Section 4 action, he will find it easy to retake power unless his disability is substantial.

Other cases covered in this chapter include a traveling President out of communication with the White House may necessitate giving power to the Vice President if decisive action is needed; and a President under criminal prosecution. Finally, the Vice President and Cabinet may worry that a possibly disabled President is on the verge of creating an imminent catastrophe. Even if Congress does not uphold the Vice President’s decision, invoking Section 4 would provide time to remove the nuclear button from the President’s hands.
Part III Section 4 in “Practice”, 11 Other Questions
Authors: Brian C Kalt
Published: August 2019

This chapter addresses a number of issues regarding the use of Section 4. They include: (1) That a President who declares he has recovered can retake power before the four-day waiting period expires, as long as the Vice President or Cabinet agree; (2) That if a dispute case goes to Congress, which has 21 days to decide, the President can retake power earlier than that if he wins a vote before the 21 days are up; (3) That Vice Presidents and Cabinets can declare over and over that the President is unable, and the President can declare over and over that he has recovered—two situations that require careful thought about how deal with them; (4) The unclear matter of whether Cabinet members who are only acting secretaries, temporarily filling vacancies, are allowed to participate in a Section 4 vote.
Introduction to the Sleep Clinic Evaluation
Authors: Mehra Reena , Foldvary-Schaefer Nancy , Grigg-Damberger Madeleine
Published: August 2019

This chapter provides an overview of the clinical evaluation of sleep disorders, including the sleep history (sleep habits, nighttime and daytime symptoms), medical/surgical history, medication use, family history, and social/environmental factors that may impact sleep. Patient assessment tools are reviewed in terms of their composition and utility. Emerging literature elucidating the benefits and efficiencies of innovative models of care is reviewed. An overview of the classification and nosology of sleep disorders is provided based on the International Classification of Sleep Disorders. The use of consumer sleep technologies and wearable devices is discussed, including the American Academy of Sleep Medicine’s issued position statement on how sleep clinicians can best incorporate these new technologies in their clinical practice.
Introduction to Sleep Testing
Authors: Foldvary-Schaefer Nancy , Grigg-Damberger Madeleine , Mehra Reena
Published: August 2019

This chapter provides an overview of sleep testing performed inside or outside the sleep laboratory. The chapter reviews the classification of sleep studies and methodology of in-lab polysomnography and home sleep apnea testing. Specifically, the indications for and relative contraindications and limitations of both procedures are discussed. Positive airway pressure (PAP) titration procedures are reviewed and the PAP-NAP, an abbreviated daytime study for patients with sleep apnea and PAP intolerance or hesitancy, is described. The authors also discuss the methodology of, indications for, and interpretation of the multiple sleep latency test and the maintenance of wakefulness test, which are daytime studies performed to evaluate excessive daytime sleepiness. Finally, the role of actigraphy in the evaluation of sleep disorders is discussed.
But I Need Marijuana to Function as a Mother!
Authors: Gorantla Sasikanth , Grigg-Damberger Madeleine
Published: August 2019

Polysomnography and multiple sleep latency testing (MSLT), along with detailed history and sleep logs and actigraphy, are essential for the diagnosis of narcolepsy with cataplexy (narcolepsy type 1). Interpreting polysomnography and MSLT data is challenging in patients with substance abuse. This chapter presents the case of a young woman with a history of substance abuse and confounding MSLT results due to covert use of recreational drugs. Recreational drugs affect sleep architecture, and the results of urine drug screening become a critical part of diagnostic evaluation in patients with substance abuse. Patients undergoing MSLT to characterize and confirm central hypersomnia need proper preparation to reduce false-positive, false-negative, and confounding results. Unexpected positive urine toxicology results are common in adolescents and adults undergoing MSLT and maintenance of wakefulness testing.