bluuebunny/crossref_metadata_2025 huggingface dataset:
Simulation of number sets based on probability distributions
Authors: Tokmachev M S
Published: November 2019

A three-parameter probability distribution is presented, modeled on the basis of the negative binomial distribution. This distribution corresponds structurally to the author’s distribution of the hyperbolic cosine type by the form of the characteristic function. The difference lies in the use of standard trigonometric cosine and sine for the characteristic function instead of the corresponding hyperbolic functions. The moment-forming polynomials of two arguments are found, derived from the recurrent differential relation to calculate the moments of distribution. A recurrent algebraic formula to produce the integer coefficients of these polynomials is introduced. The set of the coefficients depending on three arguments is ordered and geometrically interpreted as a numerical prism. Numerical prism sections are numerical triangles and numerical sequences. Among the sections of the prism there are well-known and new numerical sets, for example, Stirling numerical triangle, Bessel numerical triangle with alternating signs of elements, alternating tangential numbers, etc. A connection with the numerical prism derived from the hyperbolic cosine type distribution is indicated.
Mathematical model of the architecture of a distributed information-measuring system based on cloud and fog technologies
Authors: Vorobyev S P
Published: November 2019

This article describes the formulation of a mathematical model for optimizing the structure of a distributed information-measuring system based on a multi-level topology. The paradigm of cloud, fog and boundary computing is used, which allows building a modern network infrastructure within the framework of the industrial IoT concept. The most typical example of the use of this paradigm may be intelligent power supply networks and distributed systems for monitoring the transportation of gas or oil products. To solve the problem, it is proposed to use an approach based on a genetic algorithm.
Algorithms for computing the sets of stochastic matrices with predefined properties, based on automaton models
Authors: Zakharov V M , Shalagin S V , Eminov B F
Published: November 2019

The formed sets of ergodic stochastic matrices are focused on solving the problem of classifying probabilistic automaton models by certain criteria/parameters of similarities or differences in the structures of ergodic stochastic matrices using the methods of applied multivariate mathematical statistics. The algorithms developed allow forming a variety of the sets of stochastic matrices through changing the transition and random entry function in a probabilistic automaton. Transition function of the autonomous probabilistic automaton allows using the probabilistic automaton operation algorithm proposed to form the sets of ergodic stochastic matrices that differ in their potencies and structures, based on implementing state set permutations with repetitions and changing the random input variable probability distributions. Defining various autonomous deterministic automaton output functions, we can use the algorithm developed to form the sets of ergodic stochastic matrices that differ in their potencies, with a specified limiting vector, based on implementing the permutations of a set of output letters with repetitions. We are also presenting the evaluations of the potencies of the sets of ergodic stochastic matrices with rational elements, represented by autonomous probabilistic automata under the given constraints.
Simple parameters spaces analysis of roto-orbital integrable Hamiltonians for an axisymmetric rigid body
Authors: Santos Josué Cardoso dos
Published: November 2019

The present work presents a test of two Hamiltonians that produce integrable models recently proposed to study the roto-orbital motion of an axisymmetric rigid body in motion under a central gravitational field. The dynamics assumed here is approached by the motion of an axisymmetric rigid body orbiting another massive spherical one. Based on the concept of intermediary, both models are treated in Hamiltonian formalism, as perturbation of the Keplerian-Eulerian motion, using canonical variables associated to the total angular momentum. An analysis of parameters introduced to visualize possible different applications are made, in this case with special focus in binary asteroid type dynamics. The parameters space analysis present comparisons of two recently proposed intermediaries with respect to the original non-analytically integrable model and with respect to each other. In conclusion, both models behave well in regions of the parameters space where they were proposed to be valid.
A test and calibration environment for the Brazilian star tracker
Authors: Fialho Marcio A A , Fernandes Hugo K B
Published: November 2019

For many spacecraft to accomplish their mission goals there is a need to have an accurate control of their spatial orientation (attitude), so that instruments aboard the spacecraft, such as remote sensing cameras, telescopes, and other scientific payload be correctly pointed to their targets. For that purpose, many spacecraft employ sophisticated attitude control systems, fed by a variety of attitude sensors: sun sensors, horizon sensors, gyroscopes, star trackers, etc. Among the attitude sensors capable of providing an absolute attitude measurement, star trackers are considered the most accurate. This work presents an overview of the test and calibration infrastructure built for an autonomous star tracker (AST) being developed by the Electro-Optics group of INPE, result of an effort to increase the competence of the country in attitude control systems.
The impact of Space Law and space debris mitigation measures on the debris scenario around the Earth
Authors: de Paula Matheus Boccaletti , Celestino Cláudia C.
Published: November 2019

In face of the growing exploration of space by humanity, at first this work aims to synthesize a little information from Space Law based on legislations and discussions on the subject. Going further, the main focus of the project are the space debris and its mitigation guidelines of the United Nations Committee on the Peaceful Uses of Outer Space. The possible consequences of non-compliance with these standards for orbits around the Earth have been investigated and the scenario at the date of approval of the document implementing the guidelines at the UN has been compared with the current scenario in order to verify the impact of the measures summarized therein on the missions launched since then.
Preliminary Experimental Results of the PHALL II-C with Improved Magnetic Circuit Design and Hollow Cathode
Authors: Martins A A , Porto M C F , Coelho H O , Ferreira J L , Ferreira I S
Published: November 2019

We are going to present preliminary experimental results for our latest PHALL thruster of the annular type, which has been greatly improved with a new magnetic circuit design that allows operation with the magnetic field perpendicular (normal configuration) or parallel (magnetic shielding) to the thruster walls; where the benefit of this last magnetic field configuration is an improvement of three orders of magnitude on the thruster’s lifetime. For the first time, we will report on PHALL II-C operation up to 620 W with the generation of up to 41.39 mN of force and 2286.22 s of specific impulse, using a hollow cathode. These tests elevate the TRL of our thruster to TRL 4, with more realistic tests planned in our near future. We will also detail current work on the control and dissipation of thermal energy which will allow our thrusters to operate for long periods of time in space.
Wildfire management in Mediterranean-type regions: paradigm change needed
Authors: Moreira Francisco , Ascoli Davide , Safford Hugh , Adams Mark A , Moreno José M , Pereira José M C , Catry Filipe X , Armesto Juan , Bond William , González Mauro E , Curt Thomas , Koutsias Nikos , McCaw Lachlan , Price Owen , Pausas Juli G , Rigolot Eric , Stephens Scott , Tavsanoglu Cagatay , Vallejo V Ramon , Van Wilgen Brian W , Xanthopoulos Gavriil , Fernandes Paulo M
Published: November 2019

During the last decades, climate and land use changes led to an increased prevalence of megafires in Mediterranean-type climate regions (MCRs). Here, we argue that current wildfire management policies in MCRs are destined to fail. Focused on fire suppression, these policies largely ignore ongoing climate warming and landscape-scale buildup of fuels. The result is a ‘firefighting trap’ that contributes to ongoing fuel accumulation precluding suppression under extreme fire weather, and resulting in more severe and larger fires. We believe that a ‘business as usual’ approach to wildfire in MCRs will not solve the fire problem, and recommend that policy and expenditures be rebalanced between suppression and mitigation of the negative impacts of fire. This requires a paradigm shift: policy effectiveness should not be primarily measured as a function of area burned (as it usually is), but rather as a function of avoided socio-ecological damage and loss.
Effect of the combined admixture of 4-methyl-norvalin and 2-Methoxy-4-formylphenol on the corrosion inhibition of low carbon steel in artificial seawater solution
Authors: Loto Roland T. , Loto Cleophas A. , Osamaige Ogaga
Published: November 2019

The synergistic effect of 4-methyl-norvalin and 2-methoxy-4-formylphenol on the corrosion inhibition of low carbon steel in artificial seawater (3.5 wt.% NaCl solution) was studied with potentiodynamic polarization technique, open circuit potential measurement and optical microscopic analysis. Results obtained from the electrochemical test showed the organic derivatives performed effectively with optimal inhibition performance of 89%. Mixed type inhibition behavior was observed. Anodic corrosion potential shift occurred because of effective surface coverage of the inhibitor molecules. The adsorption mode was determined to occur through physisorption reaction from thermodynamic calculations in agreement with the Langmuir, Frumkin and Freundlich isotherms at correlation coefficients beyond 0.7. Corroded morphology of steel occurred without with inhibitor compared to the steel from solution at highest inhibitor concentration.
Degradation of methylene blue under UV and visible light illumination by yttria doped titania nanoparticles
Authors: Grabis J , Jankoviča Dz , Sipola I
Published: November 2019

Yttria doped TiO2nanoparticles were prepared by sol-gel method using the non-aqueous solutions in presence of urea and without it followed by calcination at 500–750 °C for 2h. Photocatalytic activity of the samples was determined by degradation methylene blue under Hg and solar light imitating illumination. Specific surface area, crystallite size, phase transition of TiO2and photocatalytic activity depend on content of Y2O3and presence of urea during synthesis. The highest photocatalytic activity showed TiO2doped with 0.8–1.0 wt.% of yttria.
Experimental Study of the Technology Parameters Affect in the Laser Welded Joints
Authors: Kovács Tünde Anna , Pinke Péter , Bitay Enikő
Published: November 2019

The laser welding technology is improving immediately rapidly nowadays. It has many advantages again the traditional welding technologies. The heat affected zone in case of the laser welding is very thin and the penetration of the joint is depth. This high energy technology work by a focused high energy laser light accompanied by protective gases. For welding process well known the different laser devices (gas laser, solid-state laser, disc laser). The effect of the gases and the technological parameters are not well known yet. In this work, we wanted to find some relationship between the welding parameters and the joint mechanical properties. To find this relationship it was welded the joint by different technologies parameters and the samples experimented the joint mechanical properties with different parameters and controlled by the experimental way.
Effects of Pumice Powder on Silicone Exterior Coating Material
Authors: Demir Mehtap , Oğuz Taha
Published: November 2019

Pumice has been used mainly in structural applications such as light-weight concretes, cements, and filters. Despite being used mostly in these areas of construction industry, pumice has very few applications in other sectors. Especially in the present investigation, it has been aimed to spread the usage of pumice in different sectors by analysing the particle size of the material. In cooperation with the factory and the processes of production of building chemicals was observed and it was investigated the characterization of the material produced by using FE-SEM. So that the microstructure images and Energy Dispersive X-ray Spectroscopy (EDS) composition analyses were obtained. It was observed that there has been a negligible amount of reaction between the Silicon and the pumice particles. In similar studies, when the doping is carried out at high temperatures, unwanted reactions (insulation, mechanical strength, etc.) occur between the particle and the base material and this affects the physical properties of the material in a negative way. In this study, due to the doping is in room conditions, there is little reaction between the particle and Silicon.
Plasticity of Red Mud and Clay Mixtures
Authors: Hamza A , Kocserha I , Géber R , Buzimov A
Published: November 2019

Recent study is focusing on the plasticity properties of clay and red mud (RM) mixtures. Two different clays were examined with (carbonate clay, CC) and without earth alkali carbonate (carbonate free clay, CFC) content. Red mud with 32 wt% moisture content was added for dried and powdered clays. Maximum applicable red mud content (30 wt%) was determined by mixing experiment. The mixtures were prepared by pan mill and samples of 33 mm in diameter and 40 mm in height were pressed. Measurements were obtained with 20, 22, 24 and 26 wt% moisture content in each mixture. Two methods were used for measurement and characterization of the plasticity of clay body. Beside determination of Pfefferkorn plasticity index, deformation curves of different samples were also recorded and analysed. Results indicated that red mud affected the forming behaviour of clays. Addition of red mud may rise the energy consumption of extrusion process.
Antimicrobial hollow fiber polypropylene/ZnO membrane for effective air filtration
Authors: Agung Sri Komaladewi Anak Agung Istri , Khoiruddin K. , Dewa Gede Ary Subagia I , Astuti Dea Indriani , Gede Wenten I
Published: November 2019

Air pollution has become an environmental problem since it poses a serious effect on human health. In addition, circulation of air containing airborne particles including pathogens in an enclosed building like a hospital may lead to more severe health effects. Therefore, an air purifier is needed to prevent the spreading of those particles through air circulation. To address the issue, an antimicrobial membrane was prepared by embedding ZnO nanoparticles onto hollow fiber polypropylene (PP) membrane. Results showed that the prepared PP/ZnO membrane had a high air filtration performance as well as antibacterial properties. The membrane also showed a high filtration capacity or permeability with a relatively low-pressure drop. With those interesting features, the newly developed PP/ZnO membrane can be applied in air filtration, in particular for indoor spaces and other medical applications.
Comparison of tensile strength of continues-core method and 4 strand modifies method of after healing of repaired Kessler rabbit’s Achilles tendon injury
Authors: Caksana P S , Kawiyana IKS , Dusak I W S , Nindhia T G T
Published: November 2019

Tendon injury causes significant morbidity during the productive age, and the number is increase in recent decades. Tensile strength is the most important factor in tendon function of style, and the results of repair should be able to withstand large current style of early mobilization. This research was an experimental research design with the post-test only control group design with the subject of the rabbit. A total of 18 research subjects who meet the requirements of the study inclusion were randomly divided into treatment and control groups. Control group was a group of rabbits that were repaired with 4 strand modified Kessler technique after Achilles tendon cut sharply. While the treatment group were a group of rabbits that were repaired with continuous-cores technique. The ratio of collagen I/III in rabbit Achilles tendon repair with the technique of continuous-cores are smaller compared to the control group with value of P <0.05. Also Showed statistical analysis tensile strength of rabbit Achilles tendon repair with the technique of continuous-core is greater than the control group at P <0.05.
Effect of Electroplating Current on Surface Morphology and Thickness of Plated-Through Hole (PTH) in Multilayer Printed Circuit Board (PCB)
Authors: Arifin Muhammad , Kamarudin  , Octowinandi Vivin , Ria Riki
Published: November 2019

Multilayer printed circuit board (PCB) consists of many layers in PCB. In order to connect one layer to other layers is needed plated-through-hole (PTH). PTH is commonly formed from the copper metal using some methods such as electroplating or electroless plating. Electroplating is method which there is adhering process the copper metal using the electrical current. This method is easy and cheap in PCB manufacture. One of the important part of electroplating result is surface morphology and thickness of PTH in multilayer PCB. The objective of this study is to im the electroplating current in electroplating process to learn more about the effect of electroplating current against the surface morphology and thickness of PTH.. The electroplating current applied in this experiment is at 5 A, 10 A, 15 A, and 20 A. In this research is also used Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray Spectroscopy (EDS) to characterize the formed PTH in multilayer PCB. The results shows that the PTH was successfully formed in through hole of multilayer PCB. The thickest PTH is about 37.8 μm for the applied current 20A and the smoothest morphology of PTH cross section is at the electroplating current 15 A.
The Porosity and Hardness of Fe-18Al Alloy Added ZrO2 Nanoparticles
Authors: Pawawoi P. , Prjitno D.H. , Adhitya R. , Manaf A.
Published: November 2019

The additive effect of ZrO2 nanoparticles in Fe-18Al based alloys through the mechanical alloying process to the porosity and hardness was investigated. Results of microstructure observations showed that the only intermetallic Fe3Al present as the major phase in the samples along with other phases which are very minor together with the presence of porosity that indicated by objects of dark color. The porosity tends to diminish with the addition of ZrO2 nanoparticles. However, the porosity is still visible on the Fe-Al alloy with the addition of 2% additive and the higher compaction load especially in the surface area. The results of phase study by XRD confirmed the presence of the intermetallic Fe3Al. It is shown that ZrO2 nanoparticles are dispersed in the metal matrix. The presence of ZrO2 also confirmed by SEMEDS. The fraction of pores that estimated based on the microstructure observation showed a decrease with an increase in volume fraction of ZrO2 nanoparticles and the compaction load. The study concluded that the hardness of Fe-18Al alloys increased with a decrease in porosity which achieved in Fe-18Al alloy added with 2% ZrO2 nanoparticles. The lowest porosity level is 0.17% and the highest hardness value is 352.59 HV
On rigid varieties with projective reduction
Authors: Li Shizhang
Published: November 2019

In this paper, we study smooth proper rigid varieties which admit formal models whose special fibers are projective. The Main Theorem asserts that the identity components of the associated rigid Picard varieties will automatically be proper. Consequently, we prove that

p
p

-adic Hopf varieties will never have a projective reduction. The proof of our Main Theorem uses the theory of moduli of semistable coherent sheaves.
Factors influencing fall departure phenology in migratory birds that bred in northeastern North America
Authors: Brisson-Curadeau Émile , Elliott Kyle H , Côté Pascal
Published: November 2019

The phenology of migrating birds is shifting with climate change. For instance, short-distance migrants wintering in temperate regions tend to delay their migration in fall during spells of warmer temperature. However, some species do not show strong shifts, and the factors determining which species will react to temperature changes by delaying their migration are poorly known. In addition, it is not known whether a slower migration or a postponed departure creates the observed delays in fall migration because most studies occur far south of the boreal breeding areas making it difficult to separate those 2 mechanisms. We used 22 yr of data at a northern observatory in eastern North America, at the southern edge of the boreal forest, to examine how 21 short-distance migrants responded to changing temperatures. We investigated if those species responding to temperature share life-history features (i.e. diet, size, total migration distance, breeding habitat, timing of migration). The period of migration in each species was, by far, the most important factor predicting the response of a species to temperature. Eight of the 13 species migrating in October changed their migration onset with temperature (usually by delaying migration by 1–2 days/°C), while the migration timing of none of the 8 species migrating in September was dependent on temperature. Furthermore, the absence of a greater migration delay by birds breeding farther from the study site (i.e. Arctic-breeding birds) suggests the mechanism is a postponed departure rather than a slower migration. We conclude that temperature variations in late fall influence the conditions on the breeding grounds, so that birds still present at that time benefit more from postponing their departure in warm weather.
Ocean warming increases availability of crustacean prey via riskier behavior
Authors: Marangon Emma , Goldenberg Silvan U , Nagelkerken Ivan
Published: November 2019

Marine prey and predators will respond to future climate through physiological and behavioral adjustments. However, our understanding of how such direct effects may shift the outcome of predator–prey interactions is still limited. Here, we investigate the effects of ocean warming and acidification on foraging behavior and biomass of a common prey (shrimps, Palaemon spp.) tested in large mesocosms harboring natural resources and habitats. Acidification did not alter foraging behavior in prey. Under warming, however, prey showed riskier behavior by foraging more actively and for longer time periods, even in the presence of a live predator. No effects of longer-term exposure to climate stressors were detected on prey biomass. Our findings suggest that ocean warming may increase the availability of some prey to predators via a behavioral pathway (i.e., increased risk-taking by prey), likely by elevating metabolic demand of prey species.
Antisense oligonucleotide therapeutics in neurodegenerative diseases: the case of polyglutamine disorders
Authors: Silva Ana C , Lobo Diana D , Martins Inês M , Lopes Sara M , Henriques Carina , Duarte Sónia P , Dodart Jean-Cosme , Nobre Rui Jorge , Pereira de Almeida Luis
Published: November 2019

Polyglutamine (polyQ) disorders are a group of nine neurodegenerative diseases that share a common genetic cause, which is an expansion of CAG repeats in the coding region of the causative genes that are otherwise unrelated. The trinucleotide expansion encodes for an expanded polyQ tract in the respective proteins, resulting in toxic gain-of-function and eventually in neurodegeneration. Currently, no disease-modifying therapies are available for this group of disorders. Nevertheless, given their monogenic nature, polyQ disorders are ideal candidates for therapies that target specifically the gene transcripts. Antisense oligonucleotides (ASOs) have been under intense investigation over recent years as gene silencing tools. ASOs are small synthetic single-stranded chains of nucleic acids that target specific RNA transcripts through several mechanisms. ASOs can reduce the levels of mutant proteins by breaking down the targeted transcript, inhibit mRNA translation or alter the maturation of the pre-mRNA via splicing correction. Over the years, chemical optimization of ASO molecules has allowed significant improvement of their pharmacological properties, which has in turn made this class of therapeutics a very promising strategy to treat a variety of neurodegenerative diseases. Indeed, preclinical and clinical strategies have been developed in recent years for some polyQ disorders using ASO therapeutics. The success of ASOs in several animal models, as well as encouraging results in the clinic for Huntington’s disease, points towards a promising future regarding the application of ASO-based therapies for polyQ disorders in humans, offering new opportunities to address unmet medical needs for this class of disorders. This review aims to present a brief overview of key chemical modifications, mechanisms of action and routes of administration that have been described for ASO-based therapies. Moreover, it presents a review of the most recent and relevant preclinical and clinical trials that have tested ASO therapeutics in polyQ disorders.
Dynamics of Intestinal Carriage of Extended-Spectrum Beta-lactamase–Producing Enterobacteriaceae in the Dutch General Population, 2014–2016
Authors: van den Bunt Gerrita , Fluit Ad C , Bootsma Martin C J , van Duijkeren Engeline , Scharringa Jelle , van Pelt Wilfrid , Bonten Marc J M
Published: November 2019

Background

In the Netherlands, the prevalence of intestinal extended-spectrum beta-lactamase–producing Enterobacteriaceae (ESBL-E) carriage in community-dwelling subjects is ~5%. Little is known about the dynamics of ESBL-E carriage.

Methods

In a nationwide, population-based study (2014–2016) with 4177 community-dwelling subjects, fecal samples from 656 subjects were collected after 1 (time point [T] = 1) and 6 (T = 2) months. The growth of ESBL-E was quantified and a whole-genome sequence analysis was performed. Subjects were categorized as either an incidental, short-term, or long-term carrier or as a noncarrier. Risk factors were determined by random forest models and logistic regression. The transmissibility and duration of ESBL-E carriage was quantified using a transmission model, which also incorporated previous study data.

Results

Out of 656 participants, 96 were ESBL-E carriers at T = 0. Of these, 66 (10.1%) subjects were incidental carriers, 22 (3.3%) were short-term carriers, and 38 (5.8%) were long-term carriers; the remaining 530 (80.8%) were noncarriers. The risk factors for long-term carriage were travelling to Asia, swimming in a sea/ocean, and not changing the kitchen towel daily. The log-transformed colony forming units ratio at T = 0 was predictive for ESBL-E carriage at T = 1 (odds ratio [OR], 1.3; 95% confidence interval [CI], 1.2–1.6) and T = 2 (OR, 1.2; 95% CI, 1.1–1.4). Model simulations revealed a median decolonization rate of 2.83/year, an average duration of carriage of 0.35 years, and an acquisition rate of 0.34/year. The trend of the acquisition rate during the study period was close to 0.

Conclusions

The risk factors for long-term ESBL-E carriage were travel- and hygiene-related. The dynamics of ESBL-E carriage in the general Dutch population are characterized by balancing decolonization and acquisition rates.
SGID: a comprehensive and interactive database of the silkworm
Authors: Zhu Zhenglin , Guan Zhufen , Liu Gexin , Wang Yawang , Zhang Ze
Published: November 2019

Although the domestic silkworm (Bombyx mori) is an important model and economic animal, there is a lack of comprehensive database for this organism. Here, we developed the silkworm genome informatics database (SGID). It aims to bring together all silkworm-related biological data and provide an interactive platform for gene inquiry and analysis. The function annotation in SGID is thorough and covers 98% of the silkworm genes. The annotation details include function description, Gene Ontology, Kyoto Encyclopedia of Genes and Genomes pathway, subcellular location, transmembrane topology, protein secondary/tertiary structure, homologous group and transcription factor. SGID provides genome-scale visualization of population genetics test results based on high-depth resequencing data of 158 silkworm samples. It also provides interactive analysis tools of transcriptomic and epigenomic data from 79 NCBI BioProjects. SGID will be extremely useful to silkworm research in the future.
Entrepreneurial Justice: Syria, the Commission for International Justice and Accountability and the Renewal of International Criminal Justice
Authors: Burgis-Kasthala Michelle
Published: November 2019

This article argues that the crisis of governance generated by the Syrian civil war presents both a challenge and an opportunity to practitioners of international criminal justice. The article also argues that, irrespective of the Syrian case, international criminal law (ICL) institutions are in need of innovation and that increasingly ICL discourses display a blurring between public and private idioms. Evaluating the contribution of the Commission of International Justice and Accountability (CIJA) is one way then of assessing how ICL might evolve. This article characterizes CIJA’s work as exemplifying ‘entrepreneurial justice’, not only in Syria but also in a range of other (post-)conflict settings. We can define entrepreneurial justice as the identification of a gap or weakness in existing public accountability fora and the creation of a new private or privatized organization and/or approach that seeks to address (at least part of) this gap. Although questions remain about CIJA’s own accountability, along with its potential contribution to realizing accountability, this article suggests that its presence within the ICL field is a necessary one and that it has already started to have effects within Syria and beyond.
Subduction of non-Newtonian plates: Thin-sheet dynamics of slab necking and breakoff
Authors: Ribe Neil M , Xu Bingrui
Published: November 2019

We use a hybrid boundary-integral/thin-sheet (‘BITS’) model to investigate the subduction of 2-D viscous sheets with composite diffusion creep/dislocation creep rheology, with a focus on the conditions required for slab necking and breakoff. To validate the model, we show that its predictions of the sinking speed of the slab follow a universal scaling law identical to one previously derived for purely Newtonian sheets. We obtain analytical expressions for the fiber stress resultant and bending moment of the sheet during deformation by pure stretching and pure bending, respectively, and show that the non-Newtonian dislocation creep component of the rheology significantly weakens the sheet for both types of deformation. We solve the BITS equations for two distinct situations: “free” subduction, in which the slab pulls an attached negatively buoyant plate without hindrance; and “arrested” subduction that slows or stops when a positively buoyant (continental) portion of the attached plate arrives at the trench. Strong lithospheric thinning is difficult to obtain in free subduction and requires dominantly non-Newtonian rheology, i.e. large (>5) values of the characteristic ratio λ of the Newtonian to the non-Newtonian viscosity. However, during arrested subduction strong thinning leading to breakoff occurs for much lower values of λ, and the point of maximum thinning is at shallower depths. These results are explained by a one-dimensional viscous dripping model (‘DRIP’) of a vertical slab with a composite rheology and an arbitrary kinematically prescribed time-dependent convergence rate U0(t). By injecting into DRIP convergence histories predicted by BITS, we find that DRIP reproduces closely the results of the more complicated BITS model. The DRIP model shows that the convergence rate controls slab breakoff in two distinct ways. On the one hand, the rate of lithospheric thinning is proportional to the accumulated convergence, i.e., the time integral of U0(t). The breakoff depth, on the other hand, is controlled by the convergence rate history, being shallower when U0 rapidly decreases (arrested subduction) after an initial period of oceanic subduction.
Cerebellar contribution to the cognitive alterations in SCA1: evidence from mouse models
Authors: Asher Melissa , Rosa Juao-Guilherme , Rainwater Orion , Duvick Lisa , Bennyworth Michael , Lai Ruo-Yah ,   CRC-SCA, Kuo Sheng-Han , Cvetanovic Marija
Published: November 2019

Spinocerebellar ataxia type 1 (SCA1) is a fatal neurodegenerative disease caused by abnormal expansion of glutamine (Q) encoding CAG repeats in the gene Ataxin-1 (ATXN1). Although motor and balance deficits are the core symptoms of SCA1, cognitive decline is also commonly observed in patients. While mutant ATXN1 is expressed throughout the brain, pathological findings reveal severe atrophy of cerebellar cortex in SCA1 patients. The cerebellum has recently been implicated in diverse cognitive functions, yet to what extent cerebellar neurodegeneration contributes to cognitive alterations in SCA1 remains poorly understood. Much of our understanding of the mechanisms underlying pathogenesis of motor symptoms in SCA1 comes from mouse models. Reasoning that mouse models could similarly offer important insights into the mechanisms of cognitive alterations in SCA1, we tested cognition in several mouse lines using Barnes maze and fear conditioning. We confirmed cognitive deficits in Atxn1154Q/2Q knock-in mice with brain-wide expression of mutant ATXN1 and in ATXN1 null mice. We found that shorter polyQ length and haploinsufficiency of ATXN1 do not cause significant cognitive deficits. Finally, ATXN1[82Q ] transgenic mice—with cerebellum limited expression of mutant ATXN1—demonstrated milder impairment in most aspects of cognition compared to Atxn1154Q/2Q mice, supporting the concept that cognitive deficits in SCA1 arise from a combination of cerebellar and extra-cerebellar dysfunctions.
Unique Characteristics of the Exoskeleton of Bythograeid Crab, Austinograea rodriguezensis in the Indian Ocean Hydrothermal Vent (Onnuri Vent Field)
Authors: Cho Boongho , Kim Dongsung , Bae Hyeonmi , Kim Taewon
Published: November 2019

The Indian Ocean hydrothermal vent is a region where a new oceanic crust is formed by magma at the interface of the deep-sea bed over 2000 m in depth. Here we examined for the first time the exoskeleton structure and mechanical properties of the bythograeid crab Austinograea Rodriguezensis living in hydrothermal vents. Scanning electron microscope and energy dispersive x-ray were used for structural analysis, and a nanoindentation system was used for mechanical analysis. The exoskeleton was divided into four layers: epicuticle, exocuticle, endocuticle, and membrane. The thickness of each layer was different from that of other crustaceans previously reported. Additionally, the number of constituent elements, composition ratio, and hardness of each layer were unique among previously studied crabs. This observation indicates that those characteristics might have evolved for creatures with a hard exoskeleton living in the deep-sea hydrothermal vent.
Effects of feeding melatonin during proestrus and early gestation to gilts and parity 1 sows to minimize effects of seasonal infertility1
Authors: Arend Lidia S , Knox Robert V , Greiner Laura L , Graham Amanda B , Connor Joseph F
Published: November 2019

This study tested whether supplemental melatonin given to mimic the extended nighttime melatonin pattern observed in the higher fertility winter season could minimize infertility during summer and fall in swine. Exogenous melatonin was fed during periods coinciding with follicle selection, corpus luteum formation, pregnancy recognition, and early embryo survival. Experiments were conducted at a commercial farm in 12 sequential replicates. In Exp. 1a, mature gilts (n = 420) that had expressed a second estrus were assigned by weight to receive once daily oral Melatonin (MEL, 3 mg) or Control (CON, placebo) at 1400 h for 3 wk starting before insemination at third estrus. In Exp. 1b, parity 1 sows (n = 470) were randomly assigned by lactation length to receive MEL or CON for 3 wk, starting 2 d before weaning. Follicles, estrus, pregnancy, and farrowing data were analyzed for the main effects of treatment, season (4-wk periods), and their interaction. Environmental measures were also analyzed for reproductive responses. In Exp. 1a, there was no effect (P > 0.10) of MEL on age at third estrus (203 d), follicle size after 7 d of treatment (5.0 mm), estrous cycle length (22.6 d), return to service (9.2%), farrowing rate (FR, 80.0%), or total born pigs (TB, 13.6). However, there was an effect of season (P = 0.03) on number of follicles and on gilts expressing estrus within 23 d of the previous estrus (P < 0.005). In Exp. 1b, there was no effect of MEL (P > 0.10) on follicle measures, wean to estrous interval, FR (84.0%), or TB (13.0). But MEL (73.5%) reduced (P = 0.03) estrous expression within 7 d of weaning compared with CON (82.0%) and season (P = 0.001) decreased FR by ~14.0% during mid summer. Also, gilts and parity 1 sows exposed to low light intensity (<45 lx) during breeding had reduced conception (−8%) and farrowing (−15%) rates, compared with higher light intensity. Similarly, high temperatures (>25 °C) during breeding also reduced gilt conception rates by 7%. Although there was clear evidence of seasonal fertility failures in gilts and sows, MEL treatment did not improve fertility in gilts and reduced estrus in parity 1 sows. It is possible that differences in lighting and thermal environments before breeding could explain the differential response to MEL in sows and gilts.
Gessner’s fossil crab
Authors: Etter Walter , Schmidt Olivier
Published: November 2019

Nearly 450 years ago, the Swiss polymath Conrad Gessner was the first to use illustrations in a systematic manner in a book devoted to the subject of fossils. In his treatise De rerum fossilium . . . liber (1565), around 200 single objects are illustrated, of which almost fifty are fossils in the modern sense. Most of the figures were illustrations of pieces from Gessner’s private collection. Against all odds, some of these have survived to the present day in the Natural History Museum in Basel, Switzerland. These remains form the oldest palaeontological reference collection in the world. Among them is the crab that figured prominently in Gessner’s book and became an icon of the early palaeontological literature.
The Association Between Affect and Sleep in Adolescents With and Without FGIDs
Authors: Monzon Alexandra D , Cushing Christopher C , Friesen Craig A , Schurman Jennifer V
Published: November 2019

Objective

Adolescents with chronic pain associated with functional gastrointestinal disorders (FGIDs) experience negative impacts on their health behaviors (i.e., sleep) and are at risk for a range of problems related to negative affect, which may serve to exacerbate one another in a reciprocal fashion. This study aimed to determine if the strength of the relationship between affect and sleep differs across community adolescents and adolescents with FGIDs. It was hypothesized that shorter sleep durations would be associated with more negative affect and longer sleep durations would be associated with more positive affect, and that group membership would moderate these relationships.

Methods

Twenty-five adolescents with FGIDs were compared with 25 matched peers to examine the differential association between affect and total sleep time (TST). Models were estimated using SAS PROC MIXED for inter- and intraindividual differences.

Results

Models predicting TST revealed a significant three-way interaction among weekday, group status, and negative affect. Simple slopes indicated that when negative affect is one standard deviation below the child’s own average on weekends, participants with FGIDs obtained significantly more sleep than those in the comparison group (β = 47.67, p < .05).

Conclusions

The findings of the present study show that when adolescents with FGIDs have lower negative affect on the weekend, when demands are likely reduced, they are able to obtain more TST. These findings confirm that unique relationships exist between negative affect and sleep duration for youth with FGIDs, and their interaction may hold value in understanding and addressing these targets.
Ellipticity of brightest cluster galaxies as tracer of halo orientation and weak-lensing mass bias
Authors: Herbonnet Ricardo , von der Linden Anja , Allen Steven W , Mantz Adam B , Modumudi Pranati , Morris R Glenn , Kelly Patrick L
Published: November 2019

Weak-lensing measurements of the masses of galaxy clusters are commonly based on the assumption of spherically symmetric density profiles. Yet, the cold dark matter model predicts the shapes of dark matter haloes to be triaxial. Halo triaxiality, and the orientation of the major axis with respect to the line of sight, are expected to be the leading cause of intrinsic scatter in weak-lensing mass measurements. The shape of central cluster galaxies (brightest cluster galaxies; BCGs) is expected to follow the shape of the dark matter halo. Here we investigate the use of BCG ellipticity as predictor of the weak-lensing mass bias in individual clusters compared to the mean. Using weak-lensing masses $M^{\rm WL}_{500}$ from the Weighing the Giants project, and M500 derived from gas masses as low-scatter mass proxy, we find that, on average, the lensing masses of clusters with the roundest/most elliptical 25 per cent of BCGs are biased ∼20 per cent high/low compared to the average, as qualitatively predicted by the cold dark matter model. For cluster cosmology projects utilizing weak-lensing mass estimates, the shape of the BCG can thus contribute useful information on the effect of orientation bias in weak-lensing mass estimates as well as on cluster selection bias.
Cosmic rays or turbulence can suppress cooling flows (where thermal heating or momentum injection fail)
Authors: Su Kung-Yi , Hopkins Philip F , Hayward Christopher C , Faucher-Giguère Claude-André , Kereš Dušan , Ma Xiangcheng , Orr Matthew E , Chan T K , Robles Victor H
Published: November 2019

The quenching ‘maintenance’ and ‘cooling flow’ problems are important from the Milky Way through massive cluster elliptical galaxies. Previous work has shown that some source of energy beyond that from stars and pure magnetohydrodynamic processes is required, perhaps from active galactic nuclei, but even the qualitative form of this energetic input remains uncertain. Different scenarios include thermal ‘heating’, direct wind or momentum injection, cosmic ray heating or pressure support, or turbulent ‘stirring’ of the intracluster medium (ICM). We investigate these in $10^{12}\!-\!10^{14}\, {\rm M}_{\odot }$ haloes using high-resolution non-cosmological simulations with the FIRE-2 (Feedback In Realistic Environments) stellar feedback model, including simplified toy energy injection models, where we arbitrarily vary the strength, injection scale, and physical form of the energy. We explore which scenarios can quench without violating observational constraints on energetics or ICM gas. We show that turbulent stirring in the central $\sim 100\,$ kpc, or cosmic ray injection, can both maintain a stable low-star formation rate halo for >Gyr time-scales with modest energy input, by providing a non-thermal pressure that stably lowers the core density and cooling rates. In both cases, associated thermal-heating processes are negligible. Turbulent stirring preserves cool-core features while mixing condensed core gas into the hotter halo and is by far the most energy efficient model. Pure thermal heating or nuclear isotropic momentum injection require vastly larger energy, are less efficient in lower mass haloes, easily overheat cores, and require fine tuning to avoid driving unphysical temperature gradients or gas expulsion from the halo centre.
A pulsar-based time-scale from the International Pulsar Timing Array
Authors: Hobbs G , Guo L , Caballero R N , Coles W , Lee K J , Manchester R N , Reardon D J , Matsakis D , Tong M L , Arzoumanian Z , Bailes M , Bassa C G , Bhat N D R , Brazier A , Burke-Spolaor S , Champion D J , Chatterjee S , Cognard I , Dai S , Desvignes G , Dolch T , Ferdman R D , Graikou E , Guillemot L , Janssen G H , Keith M J , Kerr M , Kramer M , Lam M T , Liu K , Lyne A , Lazio T J W , Lynch R , McKee J W , McLaughlin M A , Mingarelli C M F , Nice D J , Osłowski S , Pennucci T T , Perera B B P , Perrodin D , Possenti A , Russell C J , Sanidas S , Sesana A , Shaifullah G , Shannon R M , Simon J , Spiewak R , Stairs I H , Stappers B W , Swiggum J K , Taylor S R , Theureau G , Toomey L , van Haasteren R , Wang J B , Wang Y , Zhu X J
Published: November 2019

We have constructed a new time-scale, TT(IPTA16), based on observations of radio pulsars presented in the first data release from the International Pulsar Timing Array (IPTA). We used two analysis techniques with independent estimates of the noise models for the pulsar observations and different algorithms for obtaining the pulsar time-scale. The two analyses agree within the estimated uncertainties and both agree with TT(BIPM17), a post-corrected time-scale produced by the Bureau International des Poids et Mesures (BIPM). We show that both methods could detect significant errors in TT(BIPM17) if they were present. We estimate the stability of the atomic clocks from which TT(BIPM17) is derived using observations of four rubidium fountain clocks at the US Naval Observatory. Comparing the power spectrum of TT(IPTA16) with that of these fountain clocks suggests that pulsar-based time-scales are unlikely to contribute to the stability of the best time-scales over the next decade, but they will remain a valuable independent check on atomic time-scales. We also find that the stability of the pulsar-based time-scale is likely to be limited by our knowledge of solar-system dynamics, and that errors in TT(BIPM17) will not be a limiting factor for the primary goal of the IPTA, which is to search for the signatures of nano-Hertz gravitational waves.
Black hole feedback and the evolution of massive early-type galaxies
Authors: Martín-Navarro Ignacio , Burchett Joseph N , Mezcua Mar
Published: November 2019

Observationally, constraining the baryonic cycle within massive galaxies has proven to be quite difficult. In particular, the role of black hole feedback in regulating star formation, a key process in our theoretical understanding of galaxy formation, remains highly debated. We present here observational evidence showing that, at fixed stellar velocity dispersion, the temperature of the hot gas is higher for those galaxies hosting more massive black holes in their centers. Analyzed in the context of well-established scaling relations, particularly the mass–size plane, the relation between the mass of the black hole and the temperature of the hot gas around massive galaxies provides further observational support to the idea that baryonic processes within massive galaxies are regulated by the combined effects of the galaxy halo virial temperature and black hole feedback, in agreement with the expectations from the EAGLE cosmological numerical simulation.