bluuebunny/crossref_metadata_2025 huggingface dataset:
DE-cadherin and Myosin II balance regulates furrow length for onset of polygon shape in syncytial Drosophila embryos
Authors: Dey Bipasha , Rikhy Richa
Published: April 2020

Cell shape morphogenesis, from spherical to polygonal, occurs in epithelial cell formation in metazoan embryogenesis. In syncytial Drosophila embryos, the plasma membrane incompletely surrounds each nucleus and is organized as a polygonal epithelial-like array. Each cortical syncytial division cycle shows a circular to polygonal plasma membrane transition along with furrow extension between adjacent nuclei from interphase to metaphase. In this study, we assess the relative contribution of DE-cadherin (also known as Shotgun) and Myosin II (comprising Zipper and Spaghetti squash in flies) at the furrow to polygonal shape transition. We show that polygonality initiates during each cortical syncytial division cycle when the furrow extends from 4.75 to 5.75 μm. Polygon plasma membrane organization correlates with increased junctional tension, increased DE-cadherin and decreased Myosin II mobility. DE-cadherin regulates furrow length and polygonality. Decreased Myosin II activity allows for polygonality to occur at a lower length than controls. Increased Myosin II activity leads to loss of lateral furrow formation and complete disruption of the polygonal shape transition. Our studies show that DE-cadherin–Myosin II balance regulates an optimal lateral membrane length during each syncytial cycle for polygonal shape transition.

This article has an associated First Person interview with the first author of the paper.
Canonical nucleators are dispensable for stress granule assembly in Drosophila intestinal progenitors
Authors: Buddika Kasun , Ariyapala Ishara S. , Hazuga Mary A. , Riffert Derek , Sokol Nicholas S.
Published: April 2020

Stressed cells downregulate translation initiation and assemble membrane-less foci termed stress granules (SGs). Although SGs have been extensively characterized in cultured cells, the existence of such structures in stressed adult stem cell pools remains poorly characterized. Here, we report that the Drosophila orthologs of the mammalian SG components AGO1, ATX2, CAPRIN, eIF4E, FMRP, G3BP, LIN-28, PABP and TIAR are enriched in adult fly intestinal progenitor cells, where they accumulate in small cytoplasmic messenger ribonucleoprotein complexes (mRNPs). Treatment with sodium arsenite or rapamycin reorganized these mRNPs into large cytoplasmic granules. Formation of these intestinal progenitor stress granules (IPSGs) depended on polysome disassembly, led to translational downregulation and was reversible. Although the canonical SG nucleators ATX2 and G3BP were sufficient for IPSG formation in the absence of stress, neither of them, nor TIAR, either individually or collectively, were required for stress-induced IPSG formation. This work therefore finds that IPSGs do not assemble via a canonical mechanism, raising the possibility that other stem cell populations employ a similar stress-response mechanism.
Ubc13–Mms2 cooperates with a family of RING E3 proteins in budding yeast membrane protein sorting
Authors: Renz Christian , Albanèse Véronique , Tröster Vera , Albert Thomas K. , Santt Olivier , Jacobs Susan C. , Khmelinskii Anton , Léon Sébastien , Ulrich Helle D.
Published: April 2020

Polyubiquitin chains linked via lysine (K) 63 play an important role in endocytosis and membrane trafficking. Their primary source is the ubiquitin protein ligase (E3) Rsp5/NEDD4, which acts as a key regulator of membrane protein sorting. The heterodimeric ubiquitin-conjugating enzyme (E2), Ubc13–Mms2, catalyses K63-specific polyubiquitylation in genome maintenance and inflammatory signalling. In budding yeast, the only E3 proteins known to cooperate with Ubc13–Mms2 so far is a nuclear RING finger protein, Rad5, involved in the replication of damaged DNA. Here, we report a contribution of Ubc13–Mms2 to the sorting of membrane proteins to the yeast vacuole via the multivesicular body (MVB) pathway. In this context, Ubc13–Mms2 cooperates with Pib1, a FYVE-RING finger protein associated with internal membranes. Moreover, we identified a family of membrane-associated FYVE-(type)-RING finger proteins as cognate E3 proteins for Ubc13–Mms2 in several species, and genetic analysis indicates that the contribution of Ubc13–Mms2 to membrane trafficking in budding yeast goes beyond its cooperation with Pib1. Thus, our results widely implicate Ubc13–Mms2 as an Rsp5-independent source of K63-linked polyubiquitin chains in the regulation of membrane protein sorting.

This article has an associated First Person interview with the first author of the paper.
Higher education as a resource management socio-cultural modernization of regions
Authors: Len'kov Roman
Published: April 2020

The monograph examines the actual theoretical and applied aspects of institutional and regulatory support for social and cultural modernization of regions, including the specification of higher education as a resource and the conditions of modernization, periodization and content of practice of management reform of higher education, the evolution of the role of forecasting in public administration the graduate school. The analysis of resource and policy support socio-cultural modernization of the regions population with higher education through the explication of the problem of the "Assembly" of the future intelligentsia as a socio-cultural potential of modernization, the role of the Institute of higher education in the solution of problems of modernization. The empirical study support a highly skilled regional population policy of modernization in four regions: Moscow region, Bashkortostan, Belgorod region and the Republic of Kalmykia. Proposals for processing of the array data of the respondents with higher education, complemented by social and cultural portraits and information card regions.
For professionals and experts on issues of science, higher education and public administration. Will be sought after by post-graduate students, teachers and scientific employees of educational and academic institutions.
Penal law of the Russian Federation: General and Special parts
Authors: Romanov Aleksandr
Published: April 2020

The focus is on the subject and objectives of penal law of the Russian Federation, its sources and methods, types of penal norms, history and types of penal systems, the provisions of the Criminal Executive code of the Russian Federation, other penal laws and normative legal acts on the activities of bodies in charge of execution of punishments, exercising control and supervision over conditionally sentenced persons and persons with a suspended sentence. The characteristic of organization and activity of criminal-Executive system of the Russian Federation, highlights the issues of its reforms. Detail the issues of legal status of convicts established the order and conditions of execution and serving sentences, the use of other measures of criminal-legal nature, means of correction of convicts, providing medical care to prisoners, the performance requirements for the serving of sentences, organisation of support of liberated and control over them.
Meets the requirements of Federal state educational standards of higher education of the last generation.
For students of law faculties of educational institutions of higher education, enrolled in the academic programs of bachelor, specialist, master and post-graduate students, teachers, practical workers of law enforcement bodies and all those interested in issues of corrections, legal status of prisoners, the penal laws and the application of other measures of criminal-legal nature.
Owning, Using, and Renting: Some Simple Economics of the “Sharing Economy”
Authors: Filippas Apostolos , Horton John J. , Zeckhauser Richard J.
Published: April 2020

New Internet-based “sharing-economy” markets enable consumer-owners to rent out their durable goods to nonowners. We model such markets and explore their equilibria both in the short run, in which ownership decisions are fixed, and in the long run, in which ownership decisions can be changed. We find that sharing-economy markets always expand consumption and increase surplus, but may increase or decrease ownership. Regardless, ownership is decoupled from individual preferences in the long run, as the rental rates and the purchase prices of goods become equal. If there are costs of bringing unused capacity to the market, they are partially passed through, creating a bias toward ownership. To test our theoretical work empirically, we conduct a survey of consumers, finding broad support for our modeling assumptions. The survey also allows us to offer a partial decomposition of the bring-to-market costs, based on attributes that make a good more or less amenable to being shared.

This paper was accepted by Joshua Gans, business strategy.
The Informational Role of Buyback Contracts
Authors: Wang Shouqiang , Gurnani Haresh , Subramanian Upender
Published: April 2020

Manufacturers often offer retailers buyback contracts to reduce retailers’ inventory costs by repurchasing unsold inventory at a prespecified returns price. We examine the signaling role of buyback contracts when the retailer is less informed about either the manufacturer’s reliability of honoring the buyback commitment (e.g., for a small/less-established manufacturer) or its product’s market potential (e.g., for a national brand manufacturer). We find that these two situations yield contrasting buyback designs: the manufacturer must distort the wholesale and returns prices downward to signal higher reliability, but upward to signal higher market potential. Nevertheless, the signaling mechanism in both cases hinges on suitably distorting the manufacturer’s returns cost (i.e., the cost of repurchasing a retailer’s unsold inventory) by influencing the retailer’s regular stock (i.e., the portion of inventory carried to meet average demand) and safety stock (i.e., the extra inventory carried to meet potential high demand). Notably, although prior research has highlighted the signaling role of the wholesale price, we show how and why, in a channel with inventory, the returns price plays a relatively more important role. In particular, efficient signaling entails that the returns price is used to distort the manufacturer’s returns cost, whereas the wholesale price is used only to mitigate the resulting distortion in the retailer’s order quantity. In fact, the returns price emerges as a more efficient signaling instrument and reverses the direction of wholesale price distortion from what is necessary if wholesale price alone is used to signal. We also examine the implications when the two dimensions of manufacturer’s private information are correlated.

This paper was accepted by Juanjuan Zhang, marketing.
Multistage Intermediation in Display Advertising
Authors: Balseiro Santiago R. , Candogan Ozan , Gurkan Huseyin
Published: April 2020

Problem definition : We consider a setting where online advertisers seek to acquire impressions from an advertising exchange through a multitier network of intermediaries, and study the mechanisms offered by the ad exchange and intermediaries when the advertisers’ values are private. Academic/practical relevance : As opposed to traditional manufacturer/retailer settings, intermediaries in display advertising auction off contingent goods that they purchase only if downstream buyers signal interest. This motivates our study of how intermediaries should bid on behalf of their customers in the mechanism of an upstream intermediary and how the structure of the intermediation network affects the profits of its participants. Methodology : We provide a game-theoretic model to study the mechanisms offered by the ad exchange and intermediaries within a practically relevant class of mechanisms. Results : We characterize a subgame perfect equilibrium of the game among the intermediaries and the seller, and show that the equilibrium mechanisms have a simple and appealing structure: intermediaries bid the virtual value associated with the maximum downstream report in the upstream intermediary’s mechanism, whenever this quantity is positive. Managerial implications : We show that economic incentives are not necessarily aligned along the network and that the position in the intermediation network has a significant impact on the profits of the intermediaries. That is, when advertisers’ value distribution has a “light tail,” upstream intermediaries profit more (relative to downstream ones). Moreover, as the tail of the advertisers’ value distribution gets heavier, downstream intermediaries profit more, and their profits eventually exceed those of upstream ones. In addition, we show that a horizontal merger may not be profitable for intermediaries, and we analyze the impact of market size on the profits of intermediaries.
Hyperopic Search: Organizations Learning About Managers Learning About Strategies
Authors: Ganz Scott C.
Published: April 2020

Early-stage experiments are central to the design-thinking approach to organizational innovation, and they are also a core practice in evidence-based management. Organizations use experiments to test new strategies in a low-stakes setting before escalating their commitment to a new initiative. Yet organizations also use experiments to evaluate managers who will implement these strategies in a high-stakes setting. I develop a formal model to demonstrate that these two types of evaluations are fundamentally incompatible. Managers who fear replacement in response to a poor experimental outcome pervert their experiments to maximize the likelihood that they succeed. This saps early experiments of much of their informational value. I show that if an organization can observe a manager's experimental strategies and the experiment’s outcomes and can commit ahead of time to an evaluation and replacement rubric, then it can resolve this agency problem. However, if a manager's experimental strategy cannot be credibly communicated, the organization will either replace good managers to induce a desirable experimental strategy or retain bad managers to alleviate the fear of replacement. I show that in low-uncertainty environments, the control exerted by the former replacement regime offers the best results, whereas, in high-uncertainty environments, commitment to retention regardless of experimental outcomes is best.
Cloud scattering influence on satellite laser altimetry data and its correction
Authors: Tang Xinming , Yao Jiaqi , Li Guoyuan , Ai Bo , Wang Zhenming , Gao Xiaoming
Published: April 2020

Satellite laser altimetry can obtain submeter or even centimeter-level surface elevation information over a large range. However, the laser will inevitably be affected by clouds during transmission through the atmosphere, which seriously affects the accuracy of altimetry. In this paper, based on laser altimetry data, cloud optical depth inversion was realized by using the Fernald method. The influence of clouds on the echo waveform data was analyzed with actual data, and a method of cloud scattering error correction was proposed. The existing error correction methods are mostly based on the results of semi-analytical Monte Carlo simulations. In observations, it is difficult to synchronously obtain the parameters required for simulation, which significantly limits the method. Therefore, a method for correcting the cloud scattering error of satellite laser altimetry data based on an exponential model is also proposed. The experimental results show that when the cloud optical depth is

0

−

2

, the root mean square error of the model is 0.05, which can correct the height measurement deviation caused by the cloud to within 5 cm and improve the availability of the laser height measurement data affected by the cloud scattering.
Method for compensation selection of a microlithographic optical system
Authors: Yu Xinfeng
Published: April 2020

Computer-aided alignment is very important for the correction of aberrations due to construction imperfections of microlithographic optical systems. The compensation results mostly depend on the selection of compensators. In this paper, an effective method for compensation selection considering optomechanical constraints is presented. The techniques are based on the linearity of compensators and treat compensator selection as a combinatorial optimization problem with the objective of minimum residual aberrations and compensator adjustment ranges. The method is reliable and offers a better combination of compensators under constraints of optomechanical structure. As an example, the method was applied to a lithographic lens with a numerical aperture (NA) of 0.75. The results show that compensators with minimum objective function value would get minimum residual aberrations and adjustment ranges compared to those with larger objective function values. This method presented in this paper could be a good solution for compensation selection in lithographic lenses and other similar optical systems.
Machine learning enabled lineshape analysis in optical two-dimensional
coherent spectroscopy
Authors: Namuduri Srikanth , Titze Michael , Bhansali Shekhar , Li Hebin
Published: April 2020

Optical two-dimensional (2D) coherent spectroscopy excels in studying
coupling and dynamics in complex systems. The dynamical information
can be learned from lineshape analysis to extract the corresponding
linewidth. However, it is usually challenging to fit a 2D spectrum,
especially when the homogeneous and inhomogeneous linewidths are
comparable. We implemented a machine learning algorithm to analyze 2D
spectra to retrieve homogeneous and inhomogeneous linewidths. The
algorithm was trained using simulated 2D spectra with known linewidth
values. The trained algorithm can analyze both simulated (not used in
training) and experimental spectra to extract the homogeneous and
inhomogeneous linewidths. This approach can be potentially applied to
2D spectra with more sophisticated spectral features.
Polarization-division and spatial-division shared-aperture nanopatch antenna arrays for wide-angle optical beam scanning
Authors: Zeng Y. S. , Qu S. W. , Wu J. W.
Published: April 2020

Chip-based optical beam scanners hold promise for future compact high-speed light detection and ranging (LIDAR) systems. Many of the demonstrated chip-based optical beam scanners are designed based on diffraction-based waveguide gratings as on-chip antennas. The waveguide grating antenna, however, only provides a typical field-of-view (FOV) of roughly 10° by tuning the input light wavelength. In this paper, polarization-division and spatial-division multiplexed nanoantenna arrays are proposed to expand the FOV of on-chip antennas. The proposed device, based on silicon-on-insulator (SOI) platform, consists of three nanoantenna groups which are densely packed and fed by a common silicon nanostrip. It is demonstrated that the combination of the optical mode-multiplexing technique and the antenna engineering allows independent controls over the interactions between multiple nanoantenna groups and the waveguide. By proper engineering of the antenna dimensions, the proposed device achieves a FOV of over 40° within a 100 nm wavelength tuning range, almost tripling that of the conventional waveguide grating antenna.
Random residual neural network–based nanoscale positioning measurement
Authors: Zhao Chenyang , Li Yang , Yao Yingxue , Deng Daxiang
Published: April 2020

In the field of positioning measurement, a combination of complex components, a stringent environment, and time-consuming calibration are the main limitations. To address these issues, this paper presents a deep learning-based positioning methodology, which integrates image processing with nanomanufacturing technology. Non-periodic microstructure with nanoscale resolution is fabricated to provide the surface pattern. The main advantage of the proposed microstructure is its unlimited measurement range. A residual neural network is used for surface pattern recognition to reduce the search area, a survival probability mechanism is proposed to improve the transmission efficiency of the network layers, and template matching and sub-pixel interpolation algorithms are combined for pattern matching. The proposed methodology defines a comprehensive framework for the development of precision positioning measurement, the effectiveness of which was collectively validated by pattern recognition accuracy and positioning measurement performance. The trained network exhibits a recognition accuracy of 97.6%, and the measurement speed is close to real time. Experimental results also demonstrate the advantages and competitiveness of the proposed approach compared to the laser interferometer method.
Spectrum-efficient hybrid PAM-DMT for intensity-modulated optical wireless communication
Authors: Li Baolong , Feng Simeng , Xu Wei
Published: April 2020

In optical wireless communication (OWC), the superimposed optical orthogonal frequency division multiplexing (O-OFDM), such as layered asymmetrically clipped O-OFDM (LACO-OFDM), can improve spectrum efficiency by appropriately combining multiple O-OFDM signals for simultaneous transmission. However, it suffers from increased receiver complexity and latency. Therefore, a novel architecture of hybrid pulse-amplitude-modulated discrete multitone modulation (HPAM-DMT) is proposed in this paper to support a spectrum-efficiency OWC link. In HPAM-DMT, a PAM-DMT signal is carefully designed by using the real parts of subcarriers and is then superimposed on the classic PAM-DMT signal for simultaneous transmission, which fully exploits the spectrum in terms of subcarriers. Moreover, thanks to the well-designed aritecture of the two superimposed PAM-DMT signals, the proposed HPAM-DMT achieves the same spectrum efficiency as the LACO-OFDM, with much lower complexity and latency. Notable improvement of the bit-error rate (BER) performance is observed for the proposed HPAM-DMT compared to LACO-OFDM under the corruption of the transmitter nonlinearity. Moreover, HPAM-DMT achieves a relatively higher power efficiency than conventional O-OFDM schemes, which makes it a competitive O-OFDM scheme for IM/DD-based OWC.
Image-free classification of fast-moving objects using “learned” structured illumination and single-pixel detection
Authors: Zhang Zibang , Li Xiang , Zheng Shujun , Yao Manhong , Zheng Guoan , Zhong Jingang
Published: April 2020

Object classification generally relies on image acquisition and subsequent analysis. Real-time classification of fast-moving objects is a challenging task. Here we propose an approach for real-time classification of fast-moving objects without image acquisition. The key to the approach is to use structured illumination and single-pixel detection to acquire the object features directly. A convolutional neural network (CNN) is trained to learn the object features. The “learned” object features are then used as structured patterns for structured illumination. Object classification can be achieved by picking up the resulting light signals by a single-pixel detector and feeding the single-pixel measurements to the trained CNN. In our experiments, we show that accurate and real-time classification of fast-moving objects can be achieved. Potential applications of the proposed approach include rapid classification of flowing cells, assembly-line inspection, and aircraft classification in defense applications. Benefiting from the use of a single-pixel detector, the approach might be applicable for hidden moving object classification.
Frequency comb with 100  GHz spacing generated by an asymmetric MQW passively mode-locked laser
Authors: Hou Lianping , Huang Yongguang , Liu Yihui , Zhang Ruikang , Wang Jiankun , Wang Baojun , Zhu Hongliang , Hou Bin , Qiu Bocang , Marsh John H.
Published: April 2020

A L-band two-section AlGaInAs/InP asymmetric multiple quantum well (QW) passively mode-locked laser has been used to generate a frequency comb with a 100 GHz spacing at a central wavelength of 1610 nm. The comb contains 10 optical lines within a 

−

3

d
B

bandwidth of 8.05 nm and 34 optical lines within a 

−

20

d
B

bandwidth of 30 nm. The mode-locked pulse duration was 440 fs. To the best of our knowledge, this is the shortest pulse duration from any directly electrically pumped QW semiconductor mode-locked laser.
Push—pull microring-assisted space-and-wavelength selective switch
Authors: Huang Yishen , Cheng Qixiang , Rizzo Anthony , Bergman Keren
Published: April 2020

We introduce a novel design of a space-and-wavelength selective switch based on microring-assisted Mach–Zehnder interferometers. Multiple pairs of overcoupled microring resonators are incorporated as efficient and narrowband phase shifters and are driven in push–pull scheme. We design and demonstrate a2×2×2λelementary switch block with full spatial and spectral switching capabilities. The switching device’s cross talk suppression and extinction ratio both exceed 21 dB. We measure over 75 GHz optical bandwidth per channel and less than 1.5 dB power penalty at10−9BER when two 32 Gbps on–off keying signals are loaded simultaneously. This new class of switching elements can further enable compact and high-performance space-and-wavelength selective switch fabrics without the need for wavelength (de)multiplexers or parallel switching planes.
Spectroscopic properties and continuous-wave laser operation of Nd:Ca0.7La0.3Mg0.3Al11.7O19 crystal
Authors: Pan Yuxin , Liu Bei , Liu Jian , Song Qingsong , Xu Jie , Li Dongzhen , Liu Peng , Ma Jie , Xu Xiaodong , Lin Hui , Xu Jun , Lebbou Kheirreddine
Published: April 2020

The polarized absorption spectra, polarized fluorescence spectra and fluorescence decay curve of Nd:Ca0.7La0.3Mg0.3Al11.7O19 (CLnA) crystal were recorded at room temperature. The Judd-Ofelt parameters Ω2, Ω4 and Ω6 were calculated to be 0.80×10−20 cm2, 3.83×10−20 cm2 and 2.71×10−20 cm2, respectively. The spontaneous transition rates, branching ratios and the radiative lifetime were calculated for the 4F3/2 excited state. The emission cross section is 4.01×10−20 cm2 at 1052 nm for σ-polarization and 0.96×10−20 cm2 at 1052 nm for π-polarization, respectively. Continuous-wave (CW) laser operations of a-cut and c-cut Nd:Ca0.7La0.3Mg0.3Al11.7O19 crystals have been demonstrated.
Computer Simulation of the O2- Superoxide Ion Stability in a Continuous Dielectric Medium
Authors: Ryabykh A.V. , Maslova O.A. , Beznosyuk S.A. , Zhukovsky M.S. , Masalimov А.S.
Published: April 2020

In this paper, computer modeling is carried out, and stability parameters (total energy, binding energy, ionization and electron affinity, vibrational frequencies) at the ground states of the O2 (X 3Zg-) molecule and the superoxide ion O2- (X 2Пg) in dielectric media are calculated. Chemical particles have been placed in the topological cavity of the continuum medium. The CPCM model takes into account cavitation energy, electrostatic and dispersion interactions with a continuous polarized solvent medium. Calculations are performed using the algorithms of the ORCA package by the method of the hybrid density functional B3LYP in the basic set 6-31+G (d). The calculated data for effective media with a dielectric constant of vacuum, benzene, and water are obtained. It is shown that an increase in the dielectric constant of the solvent significantly increases the stability of the O2- superoxide ion with respect to oxidation and transition to an inactivated state of an oxygen molecule with a calculated electron affinity of 0.495 eV, 2.723 eV, 3.803 eV for vacuum, benzene, and water, respectively.
Boron Diffusion in Steel 20
Authors: Shevchuk E.P. , Plotnikov V.A. , Bektasova G.S.
Published: April 2020

As is known, boriding is carried out to increase the wear resistance and corrosion resistance of iron-carbon alloys. Along with high hardness, borides, unfortunately, have very high fragility and high refractoriness. An effective way to counter the fragility of boride layers is to form a composite structure consisting of inclusions of solid borides in a more plastic matrix. Such coatings can be obtained by volumetric heating in a muffle furnace using a boron paste that besides a mixture of iron and boron powders contained ammonium hydroxide and activated carbon with or without liquid glass. Boriding of a surface is carried out at high temperatures =1000 °С for 5 minutes. It is experimentally found that the microhardness of the surface layer increased by about 30% compared with the microhardness of the substrate, and that the thickness of the boride layer depends on the presence of liquid glass in the coating. It has been established that specially calculated proportions of ammonia, liquid glass, and charcoal contribute to the formation of an extensive diffusion zone of iron borides, the formation of which is due to the anomalously high diffusion mass transfer of boron into the matrix.
Central Symmetry of Star-Shaped Flat Bodies
Authors: Polikanova I.V.
Published: April 2020

Well-known criteria for the central symmetry are formulated for convex bodies. This study relates to a broader class of star-shaped bodies but is limited by the dimension of 2. The paper introduces the concepts of a sector and a segment of a flat star-shaped body.The basic result is the following. Let a flat body K be star-shaped with respect to its interior point o. On the set of sectors and segments of K, a simply additive, monotonic, and invariant with respect to central symmetry with the center o functional F is given. The body K is centrally symmetric with respect to the center o if and only if every chord passing through the point o divides K into two sectors with equal values of the functional F.The method of proof is — "on the contrary".When considering quantities having geometric meaning (central geometric moments, area) as such functionals, we get both new and known (for an area) statements for flat convex bodies. A slight modification of the proof allows us to obtain a similar statement for the perimeter (an additive functional, but simply not an additive functional on the set of convex flat bodies): flat convex body has its central symmetry if and only if all the chords, dividing the perimeter into halves, pass through one point.
Pathophysiology, Diagnosis, and Treatment of Colonic Gallstone Ileus in an Elderly Patient
Authors: Laxague Francisco , Ramos Paula M. , Zanfardini Andrés , Schlottmann Francisco
Published: April 2020

Gallstone ileus is a rare entity, and an obstructing gallstone in the left colon is even less frequent. A 78-year-old man was evaluated for abdominal distension and pain, associated with a lack of bowel movements in the past 5 days. An abdominal computed tomography showed a cholecystocolonic fistula associated with a gallstone in the descending colon. During the operation, the gallstone was retrieved through a longitudinal colotomy proximal to the impaction site, which was then closed.
Acute Liver Failure in a Patient With Dengue Shock Syndrome
Authors: Lewis Justin , Mitra Arnab , Chang Michael
Published: April 2020

Dengue is an arboviral disease of significant burden in tropical countries. It commonly affects the liver, ranging in presentation from asymptomatic transaminitis to acute liver failure. We present a young woman from India who developed acute liver failure because of dengue shock syndrome and improved without a liver transplant. We review the disease characteristics and management of dengue, with a focus on the natural history of illness and how to approach the possible need for liver transplant in these patients.
Barack Obama’s Eulogy for the Reverend Clementa Pinckney, June 26, 2015: Grace as the Vehicle for Collective Salvation and Obama’s Agency on Civil Rights
Authors: Bostdorff Denise M. , Goldzwig Steven R.
Published: April 2020

In his eulogy for Rev. Clementa Pinckney, President Obama responded to postracial claims in the United States and to criticism that he had not done enough for black Americans by drawing on grace as the vehicle for collective salvation and his own agency on civil rights. Eulogizing Pinckney as a man of faith and grace, Obama affırmed the black church’s dual focus on religious faith and collective civil rights action as exemplary of American civil religion and treated Dylann Roof’s heinous act as both emanating from the sin of slavery and embodying prevenient grace that had led the nation to acceptance of justifying grace and the need for sanctifying action as he discussed the Confederate flag, systemic racism, and gun violence. In encouraging the ongoing work of collective sanctifıcation, Obama employed code-switching, particularly in his delivery, which served to heighten and reinforce his powerful message.
Technical Aspects of Automated Item Generation for Blended Learning Environments in Biology
Authors: Timm Justin , Otto Benjamin , Schramm Thilo , Striewe Michael , Schmiemann Philipp , Goedicke Michael
Published: April 2020

Using two case studies from biology, the article demonstrates and analyses how domain-specific self-learning items with variable content can be generated automatically for a blended learning environment. It shows that automated item generation works well even for highly specific technical properties and that a good item quality can be produced. Evaluations are based on sample exercises from two courses in botany and genetics, each with more than 100 participants.
Delayed bowel perforation after routine distal loopogram prior to ileostomy closure
Authors: Poh Keat Seong , Hoh Siew Yep , Aziz Rezal , Chong Shun Siang , Roslani April Camilla
Published: April 2020

Ultra-low anterior resection for low rectal cancer is usually done with a covering ileostomy as a safety measure to reduce the consequences of distal anastomotic failure. In many centres, distal loopogram is performed routinely, prior to the closure of the loop ileostomy, to assess the integrity of anastomosis. Distal loopogram is generally considered a safe procedure with very low complication rates, especially when water-soluble contrast is used. We report two cases of delayed bowel perforation which led to severe sepsis and generalized peritonitis after distal loopogram prior to ileostomy closure. Our cases highlight the potential dangers of distal loopogram. Therefore, the routine usage of this procedure should be scrutinized and the patient needs to be properly counselled prior to the procedure.
Diagnostic accuracy of MALDI-TOF mass spectrometry for the direct identification of clinical pathogens from urine
Authors: Tang Min , Yang Jia , Li Ying , Zhang Luhua , Peng Ying , Chen Wenbi , Liu Jinbo
Published: April 2020

Matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS) has become one of the most popular methods for the rapid and cost-effective detection of clinical pathogenic microorganisms. This study aimed to evaluate and compare the diagnostic performance of MALDI-TOF MS with that of conventional approaches for the direct identification of pathogens from urine samples. A systematic review was conducted based on a literature search of relevant databases. The pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR) and area under the summary receiver operating characteristic (SROC) curve of the combined studies were estimated. Nine studies with a total of 3920 subjects were considered eligible and included in the meta-analysis. The pooled sensitivity was 0.85 (95% CI 0.79-0.90), and the pooled specificity was 0.93 (95% CI 0.82-0.97). The PLR and NLR were 11.51 (95% CI 4.53-29.26) and 0.16 (95% CI 0.11-0.24), respectively. The area under the SROC curve was 0.93 (95% CI 0.91-0.95). Sensitivity analysis showed that the results of this meta-analysis were stable. MALDI-TOF MS could directly identify microorganisms from urine samples with high sensitivity and specificity.
Terahertz based non-destructive testing (NDT)
Authors: Nüßler Dirk , Jonuscheit Joachim
Published: April 2020

Established methods based on X-rays, ultrasound, thermography, eddy current, and optics are very effective in fault detection and structural analysis. However, these methods are limited for some applications, for example, the non-destructive testing of fiber-reinforced plastics, foams, and sandwich or hollow structures. In these cases, terahertz technology offers an innovative method to overcome these limitations. Tremendous advances have been made in this new technology in terms of their industrialization in recent years. This paper presents techniques for use in industrial applications.
Finding the Biological
Authors: Creager Angela N. H.
Published: April 2020

This essay is part of a special issue entitled “Looking Backward, Looking Forward: HSNS at 50,” edited by Erika Lorraine Milam.
ПОСТТРАВМАТИЧНЕ ЖИТТЄТВОРЕННЯ ОСОБИСТОСТІ: МЕТОДИ ДІАГНОСТИКИ І ВІДНОВЛЕННЯ
Authors: Титаренко Тетяна
Published: April 2020

Представлено емпіричну верифікацію наступних аспектів теорії відновлення психологічного здоров’я особистості: діапазону психологічних наслідків впливу травми на особистість; способів розподілу ресурсів особистості у складних умовах; засобів та процедур визначення ефективності реабілітаційних впливів; перс­пектив забезпечення комплексної психосоціальної підтримки особистості. Апробовано комплекс ме­тодик, який використовувався колективом лабораторії соціальної психології особистості при дослідженні посттравматичного етапу життєтворення.

Показали свою ефективність наступні методи діагностики: методи опитування, глибинного та контекстуального інтерв’ю, створення автонаративу. Інтерпретація результатів, отриманих в резуль­та­ті використання якісних методів, здійснювалася за допомогою процедур контент-аналізу та аналізу твор­чих продуктів. Засвідчено інформативність методу інтерв’ю, завдяки якому вдалося виявити вплив трав­матичних життєвих обставин на способи організації життєтворення, зміни стилю життя, апробацію нових копінгів.

Доведено формувально-відновлювальний вплив методів соціально-психологічної реабілітації на осо­бис­тість. Здійснено перевірку ефективності реабілітаційних технологій з використанням методу феноме­нологічного аналізу індивідуальних та групових впливів та подальшим аналізом консультативних, психоте­рапевтичних і тренінгових текстів, що дало змогу з’ясувати феноменологію травматичного досвіду постра­ж­далих, зафіксувати наявність внутрішніх і зовнішніх ресурсів для відновлення їхнього психоло­гіч­ного здоров’я та  реконструювати ціннісно-смислові і праксеологічні контексти посттравматичного життєтворення.
Destination Therapy with Left Ventricular Assist Devices in Non-transplant Centres: The Time is Right
Authors: Bayes-Genis Antoni , Muñoz-Guijosa Christian , Santiago-Vacas Evelyn , Montero Santiago , García-García Cosme , Codina Pau , Núñez Julio , Lupón Josep
Published: April 2020

For almost half a century, cardiac transplant has been the only long-term treatment for patients with end-stage heart failure. Implantable left ventricular assist devices (LVADs) have emerged as a new treatment option for advanced heart failure as destination therapy for patients either too old or not suitable for transplant. A meta-analysis presenting head-to-head comparisons of cardiac transplant versus LVAD as destination therapy (LVAD-DT) found no difference in 1-year mortality rates between LVAD-DT and cardiac transplant (OR 1.49; 95% CI [0.48–4.66]; I2=82.8%). Moreover, a recent subanalysis from the Interagency Registry for Mechanically Assisted Circulatory Support found similar outcomes after LVAD-DT implantation in both transplant and non-transplant centres. The time is right for LVAD-DT in non-transplant centres, provided multidisciplinary heart failure teams and expertise are in place.
Combining SEM and Mercury Intrusion Capillary Pressure in the characterization of pore-throat distribution in tight sandstone and its modification by diagenesis: A case study in the Yanchang Formation, Ordos Basin, China
Authors: Wang Wei , Yu Caili , Zhao Le , Xu Shuang , Gao Lei
Published: April 2020

Determining the characteristics of pore-throat structures, including the space types present and the pore size distribution, is essential for the evaluation of reservoir quality in tight sandstones. In this study, the results of various testing methods, including scanning electron microscopy (SEM), pressure-controlled porosimetry (PCP) and rate-controlled porosimetry (RCP), were compared and integrated to characterize the pore size distribution and the effects of diagenesis upon it in tight sandstones from the Ordos Basin, China. The results showed that reservoir spaces in tight sandstones can be classified into those with three types of origins (compaction, dissolution, and clay-related) and that the sizes and shapes of pore space differ depending on origin. Considering the data obtained by mercury injection porosimetry and the overestimation of pore radii by pressure-controlled porosimetry, the full-range pore size distribution of tight sandstones can be determined by combining data from PCP with corrected RCP data. The pore-throat radii in tight sandstone vary from 36 nm to 200 μm, and the distribution curve is characterized by three peaks. The right peak remains similar across the sample set and corresponds to residual intergranular pores and dissolution pores. The middle and left peaks show variation between samples due to the heterogeneity and complexity of nano-scale throat bodies. The average micro-scale pore content is 33.49%, and nano-scale throats make up 66.54%. The nano-scale throat spaces thus dominate the reservoir space of the tight sandstones. Compaction, dissolution, carbonate cementation, and clay cementation have various effects on pore-throats. Compaction and carbonate cementation decrease pore body content. Pore-bridging clay cementation decreases throat space content. As pore-lining clay cementation preserves pore space.
Numerical Simulation and Model of Deformation Features of Destabilized Mining Slope Under Fault-Controlled Conditions
Authors: Lv Yiqing
Published: April 2020

This paper took the Fengmaoding slope, typically found in the mountainous areas of central Shanxi province, as its research area. The stratum structure of the Fengmaoding slope is a typical coal measures stratum covered by a layer of loess. There are communication towers on the slope mass and top of the slope; railways, roads, and rivers at the foot of the slope. There are many villages across from the slope, therefore, the buildings and structures nearby, even the lives of the villagers are threatened by the damages caused by the deformation of the slope. Tectonic development and mining activities have very profound effects on the stability of the slope. Considering the above, this paper analyzed the effects of the fault in controlling the deformation features of the destabilized slope during underground mining by adopting the method of numerical simulation from these perspectives including displacement, stress, strain, among others. under different circumstances (the faulted and unfaulted) so as to provide guidance for future studies about landslides of the same type and give preventive proposals for reference.
Precisión discriminatoria de pruebas serológicas para Trypanosoma cruzi aplicando metodología estándar y de curva COR
Authors: Querales Marvin , De Lima Ana Rita , Martínez-de Cordero Harú , Cannova Domenica Carolina , Simons María Isabel , Pérez-Ybarra Luis
Published: April 2020

Introducción. Las pruebas serológicas se utilizan para detectar infección por Trypanosoma cruzi y su precisión discriminatoria depende del umbral de decisión establecido. La metodología estándar y la de curva característica operativa del receptor (COR) permiten obtener tal umbral.Objetivo. Comparar la precisión discriminatoria de la metodología estándar y la metodología de curva COR en lo que respecta a pruebas serológicas para detectar infección por T. cruzi.Materiales y métodos. Se utilizó un conjunto de valores de anticuerpos contra T. cruzi de individuos clasificados como chagásicos o sanos y se realizaron simulaciones computarizadas en condiciones homocedásticas y heterocedásticas. Se calculó sensibilidad, especificidad, sensibilidad=100%, especificidad=100% y decisión-perfecta.Resultados. La precisión discriminatoria de la metodología estándar favoreció la especificidad (98.22% a 99.56%) sobre la sensibilidad (67.25% a 87.14%), mientras que la de la curva COR mostró un equilibrio entre sensibilidad (94.56% y 96.44%) y especificidad (90.35% y 92.11%). Esta última metodología también evidenció una mayor proporción de decisión-perfecta, la cual llegó a ser >90% en condiciones de homocedasticidad. Los umbrales de decisión fueron afectados por las condiciones de heterocedasticidad.Conclusión. La metodología de la curva COR mostró una mejor precisión discriminatoria, por lo que se recomienda su uso para el cálculo de umbrales de decisión en pruebas serológicas para la enfermedad de Chagas.
Big data, farmacoepidemiología y farmacovigilancia
Authors: Sanchez-Duque Jorge Andrés , Gaviria-Mendoza Andres , Moreno-Gutierrez Paula Abdrea , Machado-Alba Jorge Enrique
Published: April 2020

Big data es un término que comprende un grupo de herramientas tecnológicas capaces de procesar conjuntos de datos heterogéneos extremadamente grandes, los cuales se recolectan de manera continua, están disponibles para ser usados y constituyen una fuente de evidencia científica.En el área de la farmacoepidemiología, los análisis generados a partir de estos conjuntos de datos pueden resultar en la obtención de terapias médicas más eficientes, con menor número de reacciones adversas y menos costosas. Asimismo, el uso de herramientas como el Text Mining o el Machine Learning también ha llevado a grandes avances en las áreas de farmacoepidemiología y farmacovigilancia, por lo que es probable que su empleo sea cada vez mayor.
El inglés en la medicina académica peruana
Authors: Vásquez-Villalobos José , Vergara-Polo Ricardo , Farro-Maldonado Marioli , Gutiérrez-Pérez Glenda , Herrera-Guzmán Adriana , Runzer-Colmenares Fernando
Published: April 2020

Estimado editor:Después de leer con satisfacción el artículo “English proficiency level in Colombian undergraduate students of medical programs”,1 publicado por su distinguida revista y con cuyas conclusiones concordamos, quisiéramos profundizar en el tema y resaltar algunos aspectos mencionados en dicho editorial.Como mencionan Alonso et al.,1 ese es el primer estudio en Colombia que evidencia que más del 20% de graduados de las diferentes facultades de medicina poseen un nivel intermedio o alto en inglés. Este porcentaje debe ser mejorado no solo en Colombia, sino también en otros países de Latinoamérica como Perú, ya que, a pesar de que el español es el idioma oficial en la mayoría de países de la región, el dominio del inglés optimizaría el uso de herramientas útiles para el estudiante de medicina en relación con el desarrollo tecnológico y la investigación.2
Variación somática intraindividual del polimorfismo rs669 del gen A2M en pacientes con cáncer colorrectal
Authors: Ramírez-Plascencia Helen Haydee Fernanda , Gutiérrez-Angulo Melva , Suárez-Villanueva Alexis Sayuri , Peregrina-Sandoval Jorge , Ayala-Madrigal María De la Luz
Published: April 2020

La variación somática intraindividual (VSI) se describe como la diferencia genética entre los tejidos de un mismo individuo. La VSI se incrementa conforme avanza la edad y se asocia con alteraciones neurológicas, hematológicas e inmunes y, de manera especial, con cáncer, aunque puede no manifestar un fenotipo definido.1Para analizar la posible VSI en pacientes mexicanos con cáncer colorrectal (CCR), Yang et al.2 estudiaron el polimorfismo rs669 (c.2998 A>G, p.Ile1000Val) del gen A2M que codifica para la proteína alfa-2 macroglobulina, una inhibidora de proteasas involucrada en la progresión y proliferación del tumor. Esta variante se localiza cerca de un sitio tioéster, necesario para la función inhibidora de la proteína.