bluuebunny/crossref_metadata_2025 huggingface dataset:
What causes mass extinctions? Large asteroid/comet impacts, flood-basalt volcanism, and ocean anoxia—Correlations and cycles
Authors: Rampino* Michael R. , Caldeira Ken , Prokoph# Andreas
Published: October 2019

What causes recurrent mass extinctions of life? We find that the ages of 10 of the 11 well-documented extinction episodes of the last 260 m.y. show correlations, at very high confidence (>99.99%), with the ages of the largest impact craters or the ages of massive continental flood-basalt eruptions. The four largest craters (≥100 km diameter, impact energies ≥3 × 107 Mt trinitrotoluene [TNT]) can be linked with recognized extinction events at 36, 66, 145, and 215 Ma, and with stratigraphic distal impact debris correlative with the extinctions. The ages of 7 out of 11 major flood-basalt episodes can be correlated with extinction events at 66, 94, ca. 120, 183, 201, 252, and 260 Ma. All seven flood-basalt–extinction co-events have coincident volcanogenic mercury anomalies in the stratigraphic record, closely linking the extinctions to the volcanism. Furthermore, the seven major periods of widespread anoxia in the oceans of the last 260 m.y. are significantly correlated (>99.99%) with the ages of the flood-basalt–extinction events, supporting a causal connection through volcanism-induced climate warming. Over Phanerozoic time (the last 541 m.y.), the six “major” mass extinctions (≥40% extinction of marine genera) are all correlated with the ages of flood-basalt episodes, and stratigraphically with related volcanogenic mercury anomalies. In only one case, the end of the Cretaceous (66 Ma), is there an apparent coincidence of a “major” mass-extinction event with both a very large crater (Chicxulub) and a continental flood-basalt eruption (the Deccan Traps).

The highly significant correlations indicate that extinction episodes are typically related to severe environmental crises produced by the largest impacts and by periods of flood-basalt volcanism. About 50% of the impacts of the past 260 m.y. seem to have occurred in clusters, supporting a picture of brief pulses of increased comet or asteroid flux. The largest craters tend to fall within these age clusters. Cross-wavelet transform analyses of the ages of impact craters and extinction events show a common, strong ~26 m.y. cycle, with the most recent phase of the cycle at ~12 Ma, correlating with a minor extinction event at 11.6 Ma.
Hepatitis B-associated hepatocellular carcinoma in a young Haitian man: a review of screening guidelines
Authors: Nazari Matthew , Rosenblum Jared Spencer , Trumbo Silas
Published: October 2019

Hepatocellular carcinoma (HCC) is a terminal, yet preventable, outcome of untreated infection with hepatitis B virus (HBV). HBV is endemic in many areas of Latin America and the Caribbean, including Haiti. Haitians have the highest incidence of liver cancer among Caribbean immigrants. Unfortunately, many of these patients are not screened, despite current guidelines. As HBV is treatable, screening of high-risk populations is crucial to early intervention and prevention of poor outcomes. We highlight the case of a young Haitian male immigrant who presented with unintentional weight loss and epigastric pain and found to have HCC associated with HBV. Despite chemotherapy, the patient died 15 months after diagnosis. Increased awareness of HBV among patients from high-incidence countries may result in early recognition of this disease and reduced morbidity and mortality from devastating complications.
Nasopharyngeal carcinoma presenting as a sixth nerve palsy and Horner’s syndrome
Authors: Batawi Hatim , Micieli Jonathan A
Published: October 2019

The combination of a sixth nerve palsy and ipsilateral Horner’s syndrome localises the disease process to the posterior cavernous sinus and can be a result of various pathologies in this region. A 74-year-old Chinese woman presented with a 9-month history of binocular horizontal diplopia worse when looking left. She was found to have a left sixth nerve palsy and Horner’s syndrome and MRI revealed an enhancing soft tissue mass in the nasopharynx with involvement of the bones of the skull base and invasion of the left cavernous sinus. Endoscopic biopsy of the mass confirmed the diagnosis of non-keratinising squamous cell carcinoma, which was Epstein-Barr virus positive. She was treated with radiation therapy. Patients with a sixth nerve palsy and ipsilateral Horner’s syndrome should have urgent neuroimaging with careful attention to the cavernous sinus since sympathetic fibres join the sixth nerve for a short distance in this location.
Developing common demographic data elements to include in future editions of the SCAT and Child SCAT: a modified international Delphi study
Authors: Shanks Maxine J , McCrory Paul , Davis Gavin A , Echemendia Ruben J , Gray Andrew R , Sullivan S John
Published: October 2019

Background

The Sport Concussion Assessment Tool (SCAT) and Child SCAT are the ‘gold standard’ assessment tools for a suspected sport-related concussion (SRC). A number of ‘modifiers’ (eg, previous history of concussion) of a SRC have been identified. These may influence how the SCAT/Child SCAT results should be interpreted.

Objectives

To achieve consensus, via an international panel of SRC experts, on which athlete/player and parent/caregiver demographic variables should be considered for inclusion in future editions of the SCAT/Child SCAT respectively.

Methods

A two-round modified Delphi technique, overseen by a steering committee, invited 41 panellists to achieve expert consensus (≥80% agreement). The first round utilised open questions to generate demographic variables; the second round used a five-point ordinal item to rank the importance of including each variable in future editions of the SCAT/Child SCAT.

Results

15 experts participated in at least one Delphi round. 29 athlete/player and eight parent/caregiver variables reached consensus for inclusion in the SCAT, whereas two parent/caregiver variables reached consensus for exclusion. 28 athlete/player and four parent/caregiver variables reached consensus for the Child SCAT, whereas two parent/caregiver variables reached consensus for exclusion. Key categories of variables included the following: concussion/sport details, personal medical conditions and family medical history.

Conclusion

This study provides a list of athlete/player and parent/caregiver demographic variables that should be considered in future revisions of the SCAT/Child SCAT. By considering (and ultimately likely including) a wider and standard set of additional demographic variables, the Concussion in Sport experts will be able to provide clinicians and researchers with data that may enhance interpretation of the individual’s data and the building of larger datasets.
Visual impairment and mortality in patients with type 2 diabetes
Authors: Siersma Volkert , Køster-Rasmussen Rasmus , Bruun Christine , Olivarius Niels de Fine , Brunes Audun
Published: October 2019

Objective

To evaluate whether visual acuity impairment was an independent predictor of mortality in patients with type 2 diabetes.

Research design and methods

This is a 19-year follow-up of a cohort of 1241 patients newly diagnosed with type 2 diabetes and aged 40 years or over. Visual acuity was assessed by practicing ophthalmologists both at diabetes diagnosis and after 6 years. The logarithmic value of the visual acuity (logMAR) was the exposure. Multivariable Cox regression models were adjusted for multiple potential confounders including cardiovascular disease, and censored for potential mediators, that is, fractures/trauma. Primary outcomes were from national registers: all-cause mortality and diabetes-related mortality.

Results

Visual impairment at diabetes diagnosis was robustly associated with subsequent 6-year all-cause mortality. Per 1 unit reduced logMAR acuity the incidence rate of all-cause mortality increased with 51% (adjusted HR: 1.51; 95% CI 1.12 to 2.03) and of fractures/trauma with 59% (HR: 1.59; 95% CI 1.18 to 2.15), but visual acuity was not associated with diabetes-related mortality. After censoring for fractures/trauma, visual acuity was still an independent risk factor for all-cause mortality (HR: 1.68; 95% CI 1.23 to 2.30). In contrast, visual acuity 6 years after diabetes diagnosis was not associated with the subsequent 13 years’ incidence of any of the outcomes, as an apparent association with all-cause mortality and diabetes-related mortality was explained by confounding from comorbidity.

Conclusions

Visual acuity measured by ophthalmologists in patients newly diagnosed with type 2 diabetes was an independent predictor of mortality in the short term.
Development of a systemic lupus erythematosus cardiovascular risk equation
Authors: Petri Michelle A , Barr Erik , Magder Laurence S
Published: October 2019

Objective

Accelerated atherosclerosis remains the major cause of late death (after 5 years) in SLE. Yet, the ‘traditional’ cardiovascular risk equations (such as Framingham) consistently underestimate the risk. We sought to construct a data-driven formula for cardiovascular risk in SLE, based on data collected during the first year in a longitudinal cohort, for research purposes.

Methods

Two risk formulas were derived: one was for a broad set of cardiovascular outcomes (myocardial infarction, stroke, onset of angina, coronary procedures such as bypass or stent, claudication, peripheral artery disease or congestive heart failure); and the other for hard outcomes (myocardial infarction or stroke). Traditional and SLE-specific risk factors for cardiovascular disease were measured during the first year of cohort participation. Using Cox proportional hazards modelling, SLE formulas to calculate the 10-year risk of a subsequent cardiovascular event were derived and compared with the Framingham (for the broader outcome) and American College of Cardiology formulas (for the hard outcomes).

Results

SLE-related risk factors for each model included mean disease activity score (as measured by the SELENA revision of the SLE Disease Activity Index), low C3 and history of lupus anticoagulant. In those with SLE-related risk factors, the estimated 10-year risk based on our formula was substantially higher than the risk estimated based on the formulas for the general population.

Conclusions

The excess cardiovascular risk among patients with SLE varies substantially depending on the SLE-related risk factors, age and traditional risk factors. Cardiovascular risk formulas based on individual data from patients with SLE may better estimate 10-year cardiovascular risk among patients with SLE than the Framingham or American College of Cardiology equations.
Evaluation of medical ethics competencies in rheumatology: local experience during national accreditation process
Authors: Pascual-Ramos Virginia , Contreras-Yáñez Irazú , Arce Salinas Cesar Alejandro , Saavedra Salinas Miguel Angel , Del Mercado Mónica Vázquez del Mercado , López Zepeda Judith , Muñoz López Sandra , Vázquez-Mellado Janitzia , Amezcua Guerra Luis Manuel , Fragoso Loyo Hilda Esther , Villarreal Alarcón Miguel Angel , Pérez Cristobal Mario , Rubio Pérez Eugenia Nadina , Torres Jiménez Alfonso Ragnar , Maldonado María del Rocio , Álvarez-Hernández Everardo
Published: October 2019

Introduction

Rheumatologists are the primary healthcare professionals responsible for patients with rheumatic diseases and should acquire medical ethical competencies, such as the informed consent process (ICP). The objective clinical structured examination is a valuable tool for assessing clinical competencies. We report the performance of 90 rheumatologist trainees participating in a station designed to evaluate the ICP during the 2018 and 2019 national accreditations.

Methods

The station was validated and represented a medical encounter in which the rheumatologist informed a patient with systemic lupus erythematosus with clinically active nephritis about renal biopsy. A trained patient–actor and an evaluator were instructed to assess ICP skills (with a focus on kidney biopsy benefits, how the biopsy is done and potential complications) in obtaining formal informed consent, delivering bad news and overall communication with patients. The evaluator used a tailored checklist and form.

Results

Candidate performance varied with ICP content and was superior for potential benefit information (achieved by 98.9% of the candidates) but significantly reduced for potential complications (37.8%) and biopsy description (42.2%). Only 17.8% of the candidates mentioned the legal perspective of ICP. Death (as a potential complication) was omitted by the majority of the candidates (93.3%); after the patient–actor challenged candidates, only 57.1% of them gave a clear and positive answer. Evaluators frequently rated candidate communications skills as superior (≥80%), but ≥1 negative aspect was identified in 69% of the candidates.

Conclusions

Ethical competencies are mandatory for professional rheumatologists. It seems necessary to include an ethics competency framework in the curriculum throughout the rheumatology residency.
Effects of tree functional diversity and environmental gradients on belowground biomass in a natural old-growth forest ecosystem
Authors: Xu Yuanjie , Zhang Yu , Li Wei , Liu Weiyi , Gu Xu , Guan Zhenhua , Yang Jie , Lu Zhiyun
Published: October 2019

The positive effects of biodiversity on aboveground biomass in natural terrestrial ecosystems have been well documented, whereas the relationships between tree biodiversity and belowground biomass remain largely unexplored. Traditionally, two sets of hypotheses based on the functional trait approach, niche complementarity (NC) and mass ratio (MR), have been proposed to explain the positive effects of biodiversity. Whereas NC emphasizes that functional discrepancy enhances the collective functioning of a given ecosystem, MR states that ecosystem functioning is mainly regulated by the functional traits of dominant species. This study explored the relative importance of these two hypotheses and the effects of forest stand and environmental characteristics on belowground biomass in an old-growth broad-leaved evergreen forest. The mean coarse-root biomass, fine-root biomass, and fine-root necromass were 117.78 ± 54.000, 4.09 ± 0.85, and 0.60 ± 0.31 Mg·ha−1, respectively. We found positive effects of functional diversity on belowground biomass; however, the community-weighted mean trait values were more relevant, indicating that MR exhibited more explanatory power than NC. The combination of informative environmental factors explained 62.0%, 53.2%, and 37.8% of the variation of coarse-root biomass, fine-root biomass, and fine-root necromass, respectively. Our results suggest that the functional identity of dominant tree species exerts more influence than functional diversity on the belowground biomass in old-growth forest ecosystems and that forest stand characteristics and topographic and edaphic factors also play important roles in shaping belowground biomass patterns in old-growth forest ecosystems.
Fermion mass and mixing in an extension of the standard model with D5 symmetry
Authors: Vien V. V. , Soi N. V.
Published: October 2019

We suggest a renormalizable standard model (SM) extension based on [Formula: see text] symmetry which accommodates leptonic mass and mixing parameters with nonzero [Formula: see text] and Dirac CP violating phase. Both normal and inverted neutrino mass ordering as well as the smallness of the active neutrino masses are generated at leading order through type-I seesaw mechanism in which the obtained physical parameters are well consistent with the global fit of neutrino oscillation data [P. F. de Salas et al., Phys. Lett. B 782, 633 (2018)], while the quark masses are in good agreement with the recent experimental data [Particle Data Group (M. Tanabashi et al.), Phys. Rev. D 98, 030001 (2018)]. The model also predicts an effective Majorana neutrino mass parameter of [Formula: see text] for normal hierarchy and [Formula: see text] for inverted hierarchy which are all well below the most current upper limit given [P. F. de Salas et al., Front. Astron. Space Sci. 5, 36 (2018); CUORE Collab. (C. Alduino et al.), Phys. Rev. Lett. 120, 132501 (2018)] and beyond the reach of the present [Formula: see text] decay experiments.
PSO for Fuzzy Clustering of Multi-view Relational Data
Authors: de Gusmão Renê Pereira , de Carvalho Francisco de Assis Tenório
Published: October 2019

Particle Swarm Optimization (PSO) is a population-based meta-heuristic known for its simplicity, being successfully used in clustering task with interesting performance. Clustering of multi-view data sets has received increasing attention since it explores multiple sources or views of data sets aiming at improving clustering accuracy. Previous studies mainly focused on PSO-based clustering of single-view vector data, neither single- nor multi-view PSO-based clustering of relational received proper attention. This paper introduces a PSO-based approach to the fuzzy clustering of multi-view relational data, which can cluster data sets described by several dissimilarity matrices, each of them representing a particular view. In this work, ten fitness functions were considered, in which eight of them were adapted to deal with multi-view relational data and to consider the relevance weights of views. These fitness functions were compared to evaluate which best fit to cluster multi-view relational data. The performance and usefulness of the proposed approach, in comparison with previous single- and multi-view relational fuzzy clustering algorithms, are illustrated with several multi-view data sets. The Adjusted Rand Index (ARI) and F-measure were used to assess the quality of fuzzy partitions provided by clustering algorithms. The results have shown that the proposed methods significantly outperformed the compared algorithms in the majority of cases.
The relative hyperbolicity and manifold structure of certain right-angled Coxeter groups
Authors: Haulmark Matthew , Nguyen Hoang Thanh , Tran Hung Cong
Published: October 2019

In this paper, we study the manifold structure and the relative hyperbolic structure of right-angled Coxeter groups with planar nerves. We then apply our results to the quasi-isometry problem for this class of right-angled Coxeter groups.
A bridge between Conway–Coxeter friezes and rational tangles through the Kauffman bracket polynomials
Authors: Kogiso Takeyoshi , Wakui Michihisa
Published: October 2019

In this paper, we build a bridge between Conway–Coxeter friezes (CCFs) and rational tangles through the Kauffman bracket polynomials. One can compute a Kauffman bracket polynomial attached to rational links by using CCFs. As an application, one can give a complete invariant on CCFs of zigzag-type.
Spacetime equilibrium at negative temperature and the attraction of gravity
Authors: Jacobson Ted , Visser Manus
Published: October 2019

We derive the Einstein equation from the condition that every small causal diamond is a variation of a flat empty diamond with the same free conformal energy, as would be expected for a near-equilibrium state. The attractiveness of gravity hinges on the negativity of the absolute temperature of these diamonds, a property we infer from the generalized entropy.
Obtaining Discriminative Colour Names According to the Context: Using a Fuzzy Colour Model and Probabilistic Reference Grounding
Authors: Falomir Zoe , Costa Vicent , Gonzalez-Abril Luis
Published: October 2019

In human-machine communication situations, perceptual and conceptual deviations can appear. The challenge of categorising colours is tackled in this paper. Colour perception is very subjective. Colours may be perceived differently depending on a person’s eye anatomy and a person’s sense of sight which adapts to the surroundings and perceives different brightness of hues depending on the context. Distinguishing more/less quantity of hues depends also on the level of expertise but also on the cultural and social environment. Colours naming involves conceptual alignment with human cognition, meaning and human understanding for referring to an object and even for discriminating among objects. Studies in cross-cultural linguistics say that humans determined prototypical colours as the centre of colour categories. Hence, a cognitive colour model should distinguish/indicate when a colour coordinate is close/far to the centre of its category. And these centres of categories should be adaptable and customisable depending on the society.

A fuzzy colour model based on HSL colour space and radial basis functions is presented in this paper. Logics have been defined to combine this fuzzy-colour model with a Probabilistic Reference And GRounding mechanism (PRAGR) in order to obtain the most discriminative colour descriptor for an object depending on the context. Two case studies related with human cognition are presented. Then further tests are carried out on a dataset where the first and second most discriminative colour is computed for each object in each scene. Finally, a survey is conducted to find out the cognitive adequacy of the obtained discriminative colour names.
AN EXPERIMENTAL STUDY ON MICROSTRUCTURE OF TUNGSTEN ALLOYS
Authors: DEMIR E. , MIRZAYEV M. N. , TUĞRUL A. B. , ABDURAKHIMOV B. A. , KARAASLAN S. İ.
Published: October 2019

The aim of this study is to provide information about microstructural and thermal properties of tungsten-based composites. Phase composition and microstructural characterization of tungsten composites were performed using X-ray diffractometer (XRD), Scanning Electron Microscopy (SEM), and Raman Spectroscopy. SEM images revealed the distribution of tungsten (W), vanadium carbide (VC) and graphite (C) powders in the tungsten matrix. The Raman spectra showed two major peaks, which are recorded at 1331 (vs) cm−1, and 1583 (vs) cm−1. These bands can be attributed to disorder graphite (D) and graphite (G). Thermogravimetric analysis (TGA) measurements were performed to determine the weight loss and thermal stability of the tungsten-based composites under argon gas atmosphere and at high temperatures. TGA measurements were performed to determine weight loss and thermal stability of tungsten-based composites under argon gas atmosphere and at high temperatures. The TG curve showed a slight weight loss in this temperature range. Mass loss is thought to be due to oxidation and gas desorption of materials.
OPTIMIZATION OF THE MACHINING PARAMETERS IN TURNING OF HARDENED HOT WORK TOOL STEEL USING CRYOGENICALLY TREATED TOOLS
Authors: NAS ENGIN , ALTAN ÖZBEK NURSEL
Published: October 2019

This paper addresses an approach based on the Taguchi method with gray relational analysis for optimizing the turning parameters of hardened DIN 1.2344 hot work tool steel (54 HRC) with multiple performance characteristics. A gray relational grade obtained from the gray relational analysis was used for the performance characteristic in the Taguchi method L[Formula: see text] (2[Formula: see text]. The optimal turning parameters for surface roughness and tool wear were determined using the parameter design proposed by the Taguchi method. Dry turning tests were carried out using cryogenically treated and untreated uncoated carbide cutting tools. The cutting tool (Untreated and Deep Cryogenic Treated), cutting speed (200, 250 and 300[Formula: see text]m/min) and feed rate (0.09, 0.12 and 0.15[Formula: see text]mm/rev) were selected as experiment parameters. The analysis results revealed that the feed rate (72.84%) was the dominant factor affecting surface roughness and the cutting speed (93.93%) was the dominant factor affecting flank wear. The optimum turning parameters for the lowest Ra values were A2B1C2 and for the lowest Vb values were A1B3C2. According to the results of gray relational analysis, the optimum parameters for minimum average surface roughness and minimum flank wear were A1B2C2.
On the first frequency of reinforced partially hinged plates
Authors: Berchio Elvise , Falocchi Alessio , Ferrero Alberto , Ganguly Debdip
Published: October 2019

We consider a partially hinged rectangular plate and its normal modes. The dynamical properties of the plate are influenced by the spectrum of the associated eigenvalue problem. In order to improve the stability of the plate, we place a certain amount of denser material in appropriate regions. If we look at the partial differential equation appearing in the model, this corresponds to insert a suitable weight coefficient inside the equation. A possible way to locate such regions is to study the eigenvalue problem associated to the aforementioned weighted equation. In this paper, we focus our attention essentially on the first eigenvalue and on its minimization in terms of the weight. We prove the existence of minimizing weights inside special classes and we try to describe them together with the corresponding eigenfunctions.
Linear theory for beams with intermediate piers
Authors: Garrione Maurizio , Gazzola Filippo
Published: October 2019

The full linear theory for hinged beams with intermediate piers is developed. The analysis starts with the variational setting and the study of the linear stationary problem. Well-posedness results are provided and the possible loss of regularity, due to the presence of the piers, is analyzed. A complete spectral theorem is then proved, explicitly determining the eigenvalues according to the position of the piers and exhibiting the fundamental modes of oscillation. A related second-order eigenvalue problem is also studied, showing that it may display nonsmooth eigenfunctions and that the fourth-order problem cannot be seen as the square of a second-order problem.
Nonlinear Free Vibrations Analysis of Delaminated Composite Conical Shells
Authors: Kamaloo Abbas , Jabbari Mohsen , Tooski Mehdi Yarmohammad , Javadi Mehrdad
Published: October 2019

This paper examines the nonlinear free vibration of laminated composite conical shells throughout the circumferential delamination. First, based on the energy method, the governing equation of motion for the shell was derived. To simplify the analysis, the nonlinear partial differential equations were reduced into a system of coupled ordinary differential equations using Galerkin’s method. Consequently, the results were obtained by the numerical methods. Finally, the effects of delamination, variations in the delamination length, conical shells characteristics, materials property and circumferential wave number on the nonlinear response of delaminated composite conical shells were examined. The results show that the presence of delamination leads to increase in the amplitude of oscillations for the shells. Besides, the increase in the delamination length and decrease of the circumferential wave number, number of layers, and half vertex angle of the cone and orthotropy bring about a decrease in the nonlinearity of delaminated composite conical shells. However, an increase of the middle surface radius of the shell leads to a reduction of the nonlinearity as well as an increase of the amplitude.
The algebraic classification of nilpotent associative commutative algebras
Authors: Kaygorodov Ivan , Rakhimov Isamiddin , Said Husain Sh. K.
Published: October 2019

In this paper, we give a complete algebraic classification of [Formula: see text]-dimensional complex nilpotent associative commutative algebras.
Improved Piezoelectric Performance of Electrospun PVDF Nanofibers with Conductive Paint Coated Electrode
Authors: Tamil Selvan R. , Jayathilaka W. A. D. M. , Hilaal A. , Ramakrishna S.
Published: October 2019

Fabrication of Nanogenerators (NGs) using Electrospun polyvinylidene fluoride (PVDF) nanofibers for sensing and energy harvesting applications is a trending research due to its flexibility, biocompatibility, low-cost, etc. Different electrode materials, polymer composites had been proposed to increase the energy output. However, the contact area between the electrode material and nanofiber mat which helps to conduct more piezoelectric charges to the electrode surface are still unexplored especially at nanoscale level. In this paper, authors have proposed the use of low-cost carbon conductive paint to increase the contact area between the electrode and nanofiber mat. The electrode material is coated with conductive paint and the NG was fabricated with that electrode to compare the performances with conventional NG. Piezoelectric performance of the proposed NG has increased substantially as it generates an open circuit voltage [Formula: see text]) of 4.5[Formula: see text]V and short circuit current [Formula: see text]) of 25[Formula: see text]nA, whereas the conventional NG can only produce 1.6 [Formula: see text]) and 1.5[Formula: see text]nA [Formula: see text]). A drop test experiment was conducted, and the device consistency was verified experimentally.
Production with a High Yield of Bacterial Cellulose Nanocrystals by Enzymatic Hydrolysis
Authors: Brandes Ricardo , de Souza Leticia , Carminatti Claudimir , Recouvreux Derce
Published: October 2019

Bacterial cellulose nanocrystals are highly crystalline structures with nanoscopic scale dimensions that have received increased attention in the nanocomposites area. Its properties, such as large surface area, low density, mechanical strength and ease of modification, are attractive to the preparation many kinds of nanomaterials applied multifunctional in various fields. Besides, the cellulose nanocrystals are from abundant and renewable sources that are biodegradable. An altemative method is to obtain bacterial cellulose nanocrystal by enzymatic hydrolysis because it is, less expensive, it does not use chemicals and it requires much less energy. In this sense, the primary objective of this study was to produce bacterial cellulose using glycerol as a carbon source and isolate nanocrystals from bacterial cellulose using the enzymatic hydrolysis. This study also investigated the yield of nanocrystals depending on the weight of the bacterial cellulose hydrogel, keeping constant some enzymes. The study shows us that the enzymatic method has the best performance when using cellulose hydrogel 2[Formula: see text]g to 40[Formula: see text][Formula: see text]L cellulase enzyme (endoglucanase) and 1[Formula: see text]mL of citrate buffer. Also, it was observed that the yield of nanocrystals decrease with increasing time required for the hydrolysis.
Gödel-type universe in f(R,G) gravity
Authors: Farasat Shamir M. , Zia Saeeda
Published: October 2019

In the current study, we discuss Gödel-type universe in [Formula: see text] gravity. Analysis has been done by considering anisotropic and perfect fluid distributions. Energy conditions for two proposed [Formula: see text] gravity models have been studied for suitable values of model parameters. Furthermore, Tolman–Oppenheimer–Volkoff equation has been developed with cylindrical coordinates in [Formula: see text] gravity. The graphical analysis for both these models suggests that Tolman–Oppenheimer–Volkoff equation is obeyed in a specific interval for the radial coordinate [Formula: see text]. A polytropic equation of state has been discussed for two [Formula: see text] gravity models. By analyzing the energy conditions, it is concluded that Gödel-type universe with both [Formula: see text] gravity models supports the expansion of the universe for certain range of radial coordinates.
Meso-alkynyl corroles and their cobalt(III), manganese(III) and gallium(III) complexes
Authors: Haas Michael , Gonglach Sabrina , Schöfberger Wolfgang
Published: October 2019

We report routes towards synthesis of novel [Formula: see text]-conjugated freebase cobalt, copper, gallium and manganese meso-alkynylcorroles. UV-vis spectra show that extensive peak broadening, red shifts, and changes in the oscillator strength of absorptions increase with the extension of [Formula: see text]-conjugation. Using density functional theory (DFT), we have carried out a first theoretical study of the electronic structure of these metallocorroles. Decreased energy gaps of about 0.3–0.4 eV between the HOMO and LUMO orbitals compared to the corresponding copper, gallium and manganese meso-5,10,15 triphenylcorrole are observed. In all cases, the HOMO energies are nearly unperturbed as the [Formula: see text]-conjugation is expanded. The contraction of the HOMO–LUMO energy gaps is attributed to the lowered LUMO energies.
Tsunami Overland Flow Characteristic and Its Effect on Palu Bay Due to the Palu Tsunami 2018
Authors: Sihombing Yeremia Immanuel , Adityawan Mohammad Bagus , Chrysanti Asrini , Widyaningtias  , Farid Mohammad , Nugroho Joko , Kuntoro Arno Adi , Kusuma Mipi Ananta
Published: October 2019

On September 28, 2018, Palu Earthquake caused tremendous damage to the coastal area of Palu, Central Sulawesi, Indonesia. The epicenter was located at 27[Formula: see text]km northeast from Donggala Beach with a 10[Formula: see text]km depth. The magnitude of the earthquake was recorded at 7.4. This study assessed the tsunami overland characteristics and its outcome on the coastal area of Palu. The analysis was conducted based on satellite images and video recordings. The satellite images taken prior and post the event, were analyzed to evaluate the morphological change along the coast. The shoreline retreated up to 158[Formula: see text]m in some places. The tsunami damaged infrastructures along the affected coastal area. Video recordings were collected and analyzed to assess the tsunami overland propagation. The data were verified by field survey. The arrival time and celerity of the wave propagation overland on open area and the urban area were studied. It was found that buildings in the urban area have a significant impact on celerity. The wave propagates faster in the open area than inside the building.
Straightening warped cones
Authors: Sawicki Damian , Wu Jianchao
Published: October 2019

We provide the converses to two results of Roe [Warped cones and property A, Geom. Topol. 9 (2005) 163–178, doi:10.2140/9t.2005.9.163]: first, the warped cone associated to a free action of an a-T-menable group admits a fibered coarse embedding into a Hilbert space, and second, a free action yielding a warped cone with property A must be amenable. We construct examples showing that in both cases the freeness assumption is necessary. The first equivalence is obtained also for other classes of Banach spaces, in particular for [Formula: see text]-spaces.
Self-Powered Solar Aerial Vehicles: Towards Infinite Endurance UAVs
Authors: Khoshnoud Farbod , Esat Ibrahim I. , de Silva Clarence W. , Rhodes Jason D. , Kiessling Alina A. , Quadrelli Marco B.
Published: October 2019

A self-powered scheme is explored for achieving long-endurance operation, with the use of solar power and buoyancy lift. The end goal is the capability of “infinite” endurance while complying with the Unmanned Aerial Vehicle (UAV) dynamics and the required control performance, maneuvering, and duty cycles. Nondimensional power terms related to the UAV power demand and solar energy input are determined in a framework of Optimal Uncertainty Quantification (OUQ). OUQ takes uncertainties and incomplete information in the dynamics and control, available solar energy, and the electric power demand of a solar UAV model into account, and provides an optimal solution for achieving a self-sustained system in terms of energy. Self-powered trajectory tracking, speed and control are discussed. Aerial vehicles of this class can overcome the flight time limitations of current electric UAVs, thereby meeting the needs of many applications. This paper serves as a reference in providing a generalized approach in design of self-powered solar electric multi-rotor UAVs.
Cenomanian to Coniacian sea-level changes in the Lower Benue Trough (Nkalagu Area, Nigeria) and the Eastern Dahomey Basin: palaeontological and sedimentological evidence for eustasy and tectonism
Authors: Gebhardt Holger , Akande Samuel O. , Adekeye Olabisi A.
Published: October 2019

The Benue Trough formed in close relation to the opening of the South Atlantic and experienced sea-level fluctuations of different magnitudes during the Cenomanian to Coniacian interval. We identify depositional environments from outcrop sections and a drilling as control record. Lines of evidence for the interpretation include facies analyses, foraminiferal assemblage composition (P/B-ratio) and the presence of planktonic deep-water indicators. While the analysis of the well data from the Dahomey Basin indicates a continuous deep-water (bathyal) environment, the succession in the Nkalagu area of the Lower Benue Trough evolved in a different and more complex way. Beginning with latest Cenomanian shoreface to shelf deposits, a long period of subsidence lasted until the middle Turonian when pelagic shales and calcareous turbidites were deposited at upper to middle bathyal depths. These conditions continued during late Turonian and Coniacian times. The general deepening trend of the Lower Benue Trough was mainly controlled by tectonic subsidence and was superimposed by eustatic sea-level changes, resulting in periodically changing palaeowater depths. We were able to identify eight sea-level rises and falls that can be attributed to 405 kyr eccentricity cycles. The amplitudes of the sea-level changes were most likely in the range of several tens to a few hundred metres. The deposition of carbonate turbidites at Nkalagu was probably triggered by eustatic sea-level lowstands.
MetaStrider
Authors: Srikanth Sriseshan , Jain Anirudh , Lennon Joseph M. , Conte Thomas M. , Debenedictis Erik , Cook Jeanine
Published: October 2019

Reduction is an operation performed on the values of two or more key-value pairs that share the same key. Reduction of sparse data streams finds application in a wide variety of domains such as data and graph analytics, cybersecurity, machine learning, and HPC applications. However, these applications exhibit low locality of reference, rendering traditional architectures and data representations inefficient. This article presents MetaStrider, a significant algorithmic and architectural enhancement to the state-of-the-art, SuperStrider. Furthermore, these enhancements enable a variety of parallel, memory-centric architectures that we propose, resulting in demonstrated performance that scales near-linearly with available memory-level parallelism.
PIMBALL
Authors: Resch Salonik , Khatamifard S. Karen , Chowdhury Zamshed Iqbal , Zabihi Masoud , Zhao Zhengyang , Wang Jian-Ping , Sapatnekar Sachin S. , Karpuzcu Ulya R.
Published: October 2019

Neural networks span a wide range of applications of industrial and commercial significance. Binary neural networks (BNN) are particularly effective in trading accuracy for performance, energy efficiency, or hardware/software complexity. Here, we introduce a spintronic, re-configurable in-memory BNN accelerator, PIMBALL:
P
rocessing
I
n
M
emory
B
NN
A
cce
L(L)
erator, which allows for massively parallel and energy efficient computation. PIMBALL is capable of being used as a standard spintronic memory (STT-MRAM) array and a computational substrate simultaneously. We evaluate PIMBALL using multiple image classifiers and a genomics kernel. Our simulation results show that PIMBALL is more energy efficient than alternative CPU-, GPU-, and FPGA-based implementations while delivering higher throughput.
On the fly synthesis of edit suggestions
Authors: Miltner Anders , Gulwani Sumit , Le Vu , Leung Alan , Radhakrishna Arjun , Soares Gustavo , Tiwari Ashish , Udupa Abhishek
Published: October 2019

When working with a document, users often perform context-specific repetitive edits – changes to the document that are similar but specific to the contexts at their locations. Programming by demonstration/examples (PBD/PBE) systems automate these tasks by learning programs to perform the repetitive edits from demonstration or examples. However, PBD/PBE systems are not widely adopted, mainly because they require modal UIs – users must enter a special mode to give the demonstration/examples. This paper presents Blue-Pencil, a modeless system for synthesizing edit suggestions on the fly. Blue-Pencil observes users as they make changes to the document, silently identifies repetitive changes, and automatically suggests transformations that can apply at other locations. Blue-Pencil is parameterized – it allows the ”plug-and-play” of different PBE engines to support different document types and different kinds of transformations. We demonstrate this parameterization by instantiating Blue-Pencil to several domains – C# and SQL code, markdown documents, and spreadsheets – using various existing PBE engines. Our evaluation on 37 code editing sessions shows that Blue-Pencil synthesized edit suggestions with a precision of 0.89 and a recall of 1.0, and took 199 ms to return suggestions on average. Finally, we report on several improvements based on feedback gleaned from a field study with professional programmers to investigate the use of Blue-Pencil during long code editing sessions. Blue-Pencil has been integrated with Visual Studio IntelliCode to power the IntelliCode refactorings feature.
Optimization of swift protocols
Authors: Barik Rajkishore , Sridharan Manu , Ramanathan Murali Krishna , Chabbi Milind
Published: October 2019

Swift, an increasingly-popular programming language, advocates the use of protocols, which define a set of required methods and properties for conforming types. Protocols are commonly used in Swift programs for abstracting away implementation details; e.g., in a large industrial app from Uber, they are heavily used to enable mock objects for unit testing. Unfortunately, heavy use of protocols can result in significant performance overhead. Beyond the dynamic dispatch often associated with such a feature, Swift allows for both value and reference types to conform to a protocol, leading to significant boxing and unboxing overheads.

In this paper, we describe three new optimizations and transformations to reduce the overhead of Swift protocols. Within a procedure, we define LocalVar, a dataflow analysis and transformation to remove both dynamic dispatch and boxing overheads. We also describe Param, which optimizes the case of protocol-typed method parameters using specialization. Finally, we describe SoleType, a transformation that injects casts when a global analysis (like type-hierarchy analysis) discovers some protocol variable must have some concrete type. We also describe how these optimizations work fruitfully together and with existing Swift optimizations to deliver further speedups.

We perform elaborate experimentation and demonstrate that our optimizations deliver an average 1.56x speedup on a suite of Swift benchmarks that use protocols. Further, we applied the optimizations to a production iOS Swift application from Uber used by millions of customers daily. For a set of performance spans defined by the developers of the application, the optimized version showed speedups ranging from 6.9% to 55.49%. A version of our optimizations has been accepted as part of the official Swift compiler distribution.
Language-integrated privacy-aware distributed queries
Authors: Salvaneschi Guido , Köhler Mirko , Sokolowski Daniel , Haller Philipp , Erdweg Sebastian , Mezini Mira
Published: October 2019

Distributed query processing is an effective means for processing large amounts of data. To abstract from the technicalities of distributed systems, algorithms for operator placement automatically distribute sequential data queries over the available processing units. However, current algorithms for operator placement focus on performance and ignore privacy concerns that arise when handling sensitive data.

We present a new methodology for privacy-aware operator placement that both prevents leakage of sensitive information and improves performance. Crucially, our approach is based on an information-flow type system for data queries to reason about the sensitivity of query subcomputations. Our solution unfolds in two phases. First, placement space reduction generates deployment candidates based on privacy constraints using a syntax-directed transformation driven by the information-flow type system. Second, constraint solving selects the best placement among the candidates based on a cost model that maximizes performance. We verify that our algorithm preserves the sequential behavior of queries and prevents leakage of sensitive data. We implemented the type system and placement algorithm for a new query language SecQL and demonstrate significant performance improvements in benchmarks.
PlanAlyzer: assessing threats to the validity of online experiments
Authors: Tosch Emma , Bakshy Eytan , Berger Emery D. , Jensen David D. , Moss J. Eliot B.
Published: October 2019

Online experiments have become a ubiquitous aspect of design and engineering processes within Internet firms. As the scale of experiments has grown, so has the complexity of their design and implementation. In response, firms have developed software frameworks for designing and deploying online experiments. Ensuring that experiments in these frameworks are correctly designed and that their results are trustworthy---referred to as internal validity---can be difficult. Currently, verifying internal validity requires manual inspection by someone with substantial expertise in experimental design.

We present the first approach for statically checking the internal validity of online experiments. Our checks are based on well-known problems that arise in experimental design and causal inference. Our analyses target PlanOut, a widely deployed, open-source experimentation framework that uses a domain-specific language to specify and run complex experiments. We have built a tool called PlanAlyzer that checks PlanOut programs for a variety of threats to internal validity, including failures of randomization, treatment assignment, and causal sufficiency. PlanAlyzer uses its analyses to automatically generate contrasts, a key type of information required to perform valid statistical analyses over the results of these experiments. We demonstrate PlanAlyzer's utility on a corpus of PlanOut scripts deployed in production at Facebook, and we evaluate its ability to identify threats to validity on a mutated subset of this corpus. PlanAlyzer has both precision and recall of 92% on the mutated corpus, and 82% of the contrasts it generates match hand-specified data.