bluuebunny/crossref_metadata_2025 huggingface dataset:
A wide survey for circumstellar disks in the Lupus complex
Authors: Teixeira P. S. , Scholz A. , Alves J.
Published: July 2020

Previous star formation studies have, out of necessity, often defined a population of young stars confined to the proximity of a molecular cloud. Gaia allows us to examine a wider, three-dimensional structure of nearby star forming regions, leading to a new understanding of their history. We present a wide-area survey covering 494 deg2 of the Lupus complex, a prototypical low-mass star forming region. Our survey includes all known molecular clouds in this region as well as parts of the Upper Scorpius and Upper Centaurus Lupus (UCL) groups of the Sco-Cen complex. We combine Gaia DR2 proper motions and parallaxes as well as ALLWISE mid-infrared photometry to select young stellar objects (YSOs) with disks. The YSO ages are inferred from Gaia color-magnitude diagrams, and their evolutionary stages from the slope of the spectral energy distributions. We find 98 new disk-bearing sources. Our new sample includes objects with ages ranging from 1 to 15 Myr and masses ranging from 0.05 to 0.5 M⊙, and consists of 56 sources with thick disks and 42 sources with anemic disks. While the youngest members are concentrated in the clouds and at distances of 160 pc, there is a distributed population of slightly older stars that overlap in proper motion, spatial distribution, distance, and age with the Lupus and UCL groups. The spatial and kinematic properties of the new disk-bearing YSOs indicate that Lupus and UCL are not distinct groups. Our new sample comprises some of the nearest disks to Earth at these ages, and thus provides an important target for follow-up studies of disks and accretion in very low mass stars, for example with ALMA and ESO-VLT X-shooter.
KiDS+VIKING-450: Improved cosmological parameter constraints from redshift calibration with self-organising maps
Authors: Wright Angus H. , Hildebrandt Hendrik , van den Busch Jan Luca , Heymans Catherine , Joachimi Benjamin , Kannawadi Arun , Kuijken Konrad
Published: July 2020

We present updated cosmological constraints for the KiDS+VIKING-450 cosmic shear data set (KV450) estimated through redshift distributions and photometric samples defined using self-organising maps (SOMs). Our fiducial analysis finds marginal posterior constraints ofS8≡σ8Ωm/0.3 = 0.716−0.038+0.043, which are smaller but otherwise consistent with previous works that have applied this data set (|ΔS8| = 0.023). We analysed additional samples and redshift distributions set up in three ways: (1) by excluding certain spectroscopic surveys during redshift calibration; (2) by excluding lower-confidence spectroscopic redshifts in redshift calibration; and (3) by considering only those photometric sources which are jointly calibrated by at least three spectroscopic surveys. In all cases, the method utilised here has been proven to be robust: we find a maximal deviation from our fiducial analysis of |ΔS8| ≤ 0.011 for all samples defined and analysed using our SOM. To demonstrate the reduction in systematic biases found within our analysis, we highlight our results when performing redshift calibration without the DEEP2 spectroscopic data set. In this case, we find marginal posterior constraints ofS8= 0.707−0.042+0.046; this is a difference, with respect to the fiducial, that is both significantly smaller and in the opposite direction with regard to the equivalent shift from previous works. These results suggest that our improved cosmological parameter estimates are not sensitive to pathological misrepresentations of photometric sources by the spectroscopy used for direct redshift calibration and, therefore, that this systematic effect cannot be responsible for the observed difference betweenS8estimates made with KV450 andPlanckCMB probes.
The DIANOGA simulations of galaxy clusters: characterising star formation in protoclusters
Authors: Bassini L. , Rasia E. , Borgani S. , Granato G. L. , Ragone-Figueroa C. , Biffi V. , Ragagnin A. , Dolag K. , Lin W. , Murante G. , Napolitano N. R. , Taffoni G. , Tornatore L. , Wang Y.
Published: July 2020

Aims. We studied the star formation rate (SFR) in cosmological hydrodynamical simulations of galaxy (proto-)clusters in the redshift range 0 <  z <  4, comparing them to recent observational studies; we also investigated the effect of varying the parameters of the star formation model on galaxy properties such as SFR, star-formation efficiency, and gas fraction.

Methods. We analyse a set of zoom-in cosmological hydrodynamical simulations centred on 12 clusters. The simulations are carried out with the GADGET-3 Tree-PM smoothed-particle hydro-dynamics code which includes various subgrid models to treat unresolved baryonic physics, including AGN feedback.

Results. Simulations do not reproduce the high values of SFR observed within protocluster cores, where the values of SFR are underpredicted by a factor ≳4 both at z ∼ 2 and z ∼ 4. The difference arises as simulations are unable to reproduce the observed starburst population and is greater at z ∼ 2 because simulations underpredict the normalisation of the main sequence (MS) of star forming galaxies (i.e. the correlation between stellar mass and SFR) by a factor of ∼3. As the low normalisation of the MS seems to be driven by an underestimated gas fraction, it remains unclear whether numerical simulations miss starburst galaxies due to overly underpredicted gas fractions or overly low star formation efficiencies. Our results are stable against varying several parameters of the star formation subgrid model and do not depend on the details of AGN feedback.

Conclusions. The subgrid model for star formation, introduced to reproduce the self-regulated evolution of quiescent galaxies, is not suitable to describe violent events like high-redshift starbursts. We find that this conclusion holds, independently of the parameter choice for the star formation and AGN models. The increasing number of multi-wavelength high-redshift observations will help to improve the current star formation model, which is needed to fully recover the observed star formation history of galaxy clusters.
Toward precision cosmochronology
Authors: Blouin Simon , Daligault Jérôme , Saumon Didier , Bédard Antoine , Brassard Pierre
Published: July 2020

The continuous cooling of a white dwarf is punctuated by events that affect its cooling rate. The most significant of these events is the crystallization of its core, a phase transition that occurs once the C/O interior has cooled down below a critical temperature. This transition releases latent heat, as well as gravitational energy due to the redistribution of the C and O ions during solidification, thereby slowing down the evolution of the white dwarf. The unambiguous observational signature of core crystallization–a pile-up of objects in the cooling sequence–was recently reported. However, existing evolution models struggle to quantitatively reproduce this signature, casting doubt on their accuracy when used to measure the ages of stellar populations. The timing and amount of the energy released during crystallization depend on the exact form of the C/O phase diagram. Using the advanced Gibbs–Duhem integration method and state-of-the-art Monte Carlo simulations of the solid and liquid phases, we obtained a very accurate version of this phase diagram that allows a precise modeling of the phase transition. Despite this improvement, the magnitude of the crystallization pile-up remains underestimated by current evolution models. We conclude that latent heat release and O sedimentation alone are not sufficient to explain the observations, and that other unaccounted physical mechanisms, possibly 22Ne phase separation, play an important role.
Convergence of the likelihood ratio method for linear response of non-equilibrium stationary states
Authors: Plecháč Petr , Stoltz Gabriel , Wang Ting
Published: July 2020

We consider numerical schemes for computing the linear response of steady-state averages with respect to a perturbation of the drift part of the stochastic differential equation. The schemes are based on the Girsanov change-of-measure theory in order to reweight trajectories with factors derived from a linearization of the Girsanov weights. The resulting estimator is the product of a time average and a martingale correlated to this time average. We investigate both its discretization and finite-time approximation errors. The designed numerical schemes are shown to be of a bounded variance with respect to the integration time which is desirable feature for long time simulations. We also show how the discretization error can be improved to second-order accuracy in the time step by modifying the weight process in an appropriate way.
Der onkologische Nutzen der pelvinen Lymphadenektomie ist beim Prostatakarzinom nicht geklärt
Authors: Weißbach Lothar , Roloff Christiane
Published: July 2020

Der Review von Fossati 2017 stellt den Wert der pLA im Rahmen der RP in Frage, weil sich aus den vorliegenden Studien kein onkologischer Nutzen ergibt. Nach wie vor ist die Beweislage wegen fehlender Evidenz dürftig. Unsere Feststellung, dass von metastasierten LK keine Streuung bisher nachgewiesen wurde, basiert auf Registerdaten, auf klinischen Studien ohne Nachweis eines pLA-Vorteils und auf Überlegungen zum genetischen Zusammenhang von LK- und Fernmetastasen. Der Verzicht auf die pLA bzw. auf die Bestrahlung eines Beckenfeldes wird durch die verbesserte Bildgebung mit dem 68Ga PSMA-PET-CT zum Nachweis von Metastasen erleichtert. Wenn LK nicht metastasieren, wird das Ergebnis der Bildgebung diagnostisch zur Therapieplanung ausreichen. Somit kann auf die pLA aus diagnostischen Gründen verzichtet werden. Komplikationen wären ausgeschlossen. Um die Frage zu klären, ob die pLA bzw. ein multimodales Behandlungskonzept intermediate- und high risk-Patienten nützen, wird ein RCT notwendig sein, in dem v. a. der nicht vollständig entfernte Primarius als Streuquelle berücksichtigt wird.
COVID-19 aus Sicht der Geriatrie
Authors: Sieber Cornel
Published: July 2020

The pandemic due to the SARS-CoV-2 virus challenges all of us in the many areas of life. Our health systems are tested for their sustainability and load capacity. SARS-CoV-2 virus-infections will become part of our lives, but they mainly threaten vulnerable and multimorbid older adults. Older people with a frailty-syndrome are challenged not only in physical, but also psychological and social domains. Adapted caring structures are required and the pandemic will introduce important ethical discussions. As examples, distribution of limited resources, requests for more Advance Care Planning as well as balancing between infection protection versus the drawbacks of long-lasting social isolation should be named. This article therefore focuses on ethical questions for older adults in times of the SARS-CoV-2 virus pandemic.
Eignung biologischer azellulärer dermaler Matrices als Hautersatz
Authors: Specht Marcin , Kelm Sorge , Mirastschijski Ursula
Published: July 2020

Einleitung Bei Gewebedefekten können epidermale und dermale Anteile der Haut verloren gehen. Häufig ist eine reduzierte Gewebeelastizität, ggf. mit Narbenkontrakturen, die die Gelenkbeweglichkeit einschränken können, die Folge. Artifizielle Kollagenmatrices und humane azelluläre dermale Matrices (ADM) stellen ein neues Verfahren der kutanen Rekonstruktion vor allem in der Verbrennungsmedizin dar.

Zielsetzung Ziel dieser Studie war es, die Eignung von ADM als dermalen Ersatz zu untersuchen. Hierbei wurden die zelluläre Migration und Differenzierung sowie die inflammatorische Reaktion auf verschiedene Matrices in einem etablierten Hautorgankulturmodell ex vivo untersucht.

Material und Methoden Reste von vitalen, operativ entnommenen Spalthauttransplantaten wurden auf humane ADM (Epiflex), deepidermalisierte humane Dermis (DED) oder artifizielle Kollagen-Elastin Matrix (KEM, Matriderm) transferiert und das epitheliale Resurfacing in einem standardisierten Wundmodell an der Luft-Feuchtigkeitsgrenze untersucht. Um den Einfluss unterschiedlicher dermaler Anteile auf das epitheliale Verhalten zu untersuchen, wurde zudem die Migration auf ADM aus papillären mit retikulären Dermisanteilen verglichen. Die Reepithelialisierung und zelluläre inflammatorische Reaktion wurden histologisch, immunhistochemisch und biochemisch analysiert.

Ergebnisse und Schlussfolgerung Die größte epitheliale Ausbreitung und Differenzierung fand auf DED (2,54 mm ± 0,43 mm, Mittelwert ± SEM) im Vergleich zu ADM (1,32 mm ± 0,44 mm, p < 0,09) oder KEM (0,77 mm ± 0,11 mm, p < 0,02) statt, was unter anderem auf promigratorische Basalmembranreste auf DED zurückzuführen ist. Die keratinozytäre Migration war deutlich größer auf papillärer ADM im Vergleich zu retikulärer ADM. Im Gegensatz zu den biologischen Matrices fand sich in der grobporigen KEM nur eine horizontale Durchwanderung des Gewebes. Die Expression proinflammatorischer Mediatoren unterschied sich je nach Hautdonor und Matrix.

Zusammenfassend ist festzustellen, dass die Struktur und Herkunft der dermalen Matrix von großer Bedeutung für die Reepithelialiserung und inflammatorische zelluläre Reaktion sind.
Das erste Mal: Wie kann ich verhüten?
Authors: Scholz Alenka
Published: July 2020

Verhütung bedeutet nicht nur, eine Schwangerschaft zu verhindern, sondern auch Schutz vor sexuell übertragbaren Krankheiten. Speziell für Teenager ist die Patienteninformation konzipiert und als Kopiervorlage verwendbar.
Isolated Scaphoid Dislocation: A Case Report and Review of the Literature
Authors: Amundsen Asgeir , Bishop Sarah N. , Moran Steven L.
Published: July 2020

Background Isolated scaphoid dislocation is an exceedingly rare event with only 55 cases described. Closed reduction followed by operative intervention with Kirschner's wires (K-wire) fixation and ligamentous reconstruction are the mainstays of treatment.

Case Description We describe a patient with a solitary scaphoid dislocation treated with initial closed reduction and urgent open reduction with K-wire stabilization and ligamentous repair. The patient was immobilized for 6 weeks and on 24-month follow-up, the patient was doing well with no limitations in his daily living, no pain, and acceptable range of motion.

Literature Review A literature review was performed on the 55 cases described in the English language. The majority of the patients were males, aged between 18 and 79 years, and presented with motor vehicle accidents as the most common mechanism. Historically, isolated scaphoid dislocations were treated with closed reduction. However, K-wire fixation and, now, K-wire fixation coupled with ligamentous injury repair remain the current treatments of choice. Avascular necrosis of the scaphoid remains a rare event with only one documented case. Overall, patients do well with only minor pain and limited wrist movements. Notably, only eight cases were associated with type-II lunates. Type-II lunates appear to be protective for carpal injury.

Clinical Relevance Although isolated scaphoid dislocations remain a rare event, understanding the anatomy and the current ability to restore carpal anatomy is important. Type-II lunates appear to confer protection from carpal injuries.
The Palmaris Longus and Its Association with Carpal Tunnel Syndrome
Authors: Boltuch Andrew D. , Marcotte Michael A. , Treat Christopher M. , Marcotte Anthony L.
Published: July 2020

Background The palmaris tendon inserts into the palmar fascia and is positioned in close association with the transverse carpal ligament. Loading of this tendon has been demonstrated to increase carpal tunnel pressures.

Purpose The purpose of this study was to determine if a relationship exists between the palmaris tendon, carpal tunnel syndrome (CTS), and handedness. The sensitivity, specificity, positive predictive value, and negative predictive value for Schaeffer's test were calculated.

Methods A retrospective review of patient charts undergoing endoscopic carpal tunnel release was performed. Rates of palmaris longus agenesis (PLA) were compared to a population matched data set. Statistical analysis was performed using a one-proportion z-test. Schaeffer's test for the palmaris longus tendon was performed on all patients and compared to intraoperative confirmation.

Results A total of 520 carpal tunnel releases were performed in 389 consecutive patients. The frequency of PLA in this surgical cohort was significantly lower compared to the population matched dataset. No correlation between handedness and laterality of CTS or PLA was found. Schaeffer's test was evaluated to yield sensitivity (93.6%), specificity (100%), positive predictive value (100%), and negative predictive value (50.8%).

Conclusion The palmaris tendon was more prevalent in a population of patients undergoing carpal tunnel release. These findings can be used to provide further insight into the pathophysiology of CTS. While Schaeffer's test was accurate in detecting the palmaris longus tendon, a negative test was frequently incorrect. Further imaging is recommended in patients with a negative Schaeffer's test when the palmaris longus is desired for surgical utilization.

Level of Evidence This is a Level III, prognostic study.
Resonance properties of magnetic helical structures
Authors: Kovalev A. S.
Published: July 2020

The dependence for the frequencies of the internal modes on the external field in spiral structures in easy-plane antiferromagnets with a small in-plane anisotropy are studied theoretically in a wide region of the fields including the spin-flop transition field. The theoretical results are compared with the known experimental data for the antiferromagnetic resonance in NdFe3(BO3)4. This comparison enabled to reconstruct the dependence for the spiral period of the magnetic structure on the external field.
Mechanisms of the photodissociations of single isolated methanol
Authors: Panajapo Pannipa , Siwawannapong Kittipan , Sagarik Kritsana
Published: July 2020

The mechanisms of the photodissociation of single isolated methanol (CH3OH) molecules in the lowest singlet-excited (S1) state were systematically studied using the complete active-space second-order perturbation theory (CASPT2) and transition state theory (TST). This theoretical study focused on the nonradiative relaxation processes that transform the S0 → S1 vertically excited molecule to the products in their respective electronic ground states. The results confirmed that O–H dissociation is the predominant exothermic process and that the formation of formaldehyde (CH2O), in which the O–H dissociated species are the precursors for the reaction in the S0 state, is the second most favorable process. For C–O dissociation, the theoretical results suggested a thermally excited precursor in a different Franck–Condon region in the S0 state, from which vertical excitation leads to a transition structure in the S1 state and spontaneously to the [CH3]· and [OH]· products in their electronic ground states. The CASPT2 and TST results also revealed the possibility of [CH3OH] → [CH2OH2] isomerization dissociation, in which another thermally excited precursor is vertically excited, and C–O dissociation and intermolecular proton transfer lead to the singlet and triplet [CH2]–[H2O] H-bond complexes in their electronic ground states. Although sufficient thermal energy to generate the precursors in the S0 state is available and the reactions are kinetically feasible at high temperatures, the strongly kinetically controlled O–H dissociation predominates the C–O and [CH3OH] → [CH2OH2] isomerization dissociations. The present results verified and confirmed the reported theoretical and experimental findings and provided insights into the thermal selectivity and interplay between thermal excitation and photoexcitation.
Biochemical and molecular characterisations of salt tolerance components in rice varieties tolerant and sensitive to NaCl: the relevance of Na+ exclusion in salt tolerance in the species
Authors: Gupta Amber , Shaw Birendra P.
Published: July 2020

Soil salinisation is a major abiotic stress in agriculture, and is especially a concern for rice production because among cereal crops, rice is the most salt-sensitive. However, the production of rice must be increased substantially by the year 2050 to meet the demand of the ever growing population. Hence, understanding the biochemical events determining salt tolerance in rice is highly desirable so that the trait can be introduced in cultivars of interest through biotechnological intervention. In this context, an initial study on NaCl response in four Indica rice varieties showed a lower uptake of Na+ in the salt-tolerant Nona Bokra and Pokkali than in the salt-sensitive IR64 and IR29, indicating Na+ exclusion as a primary requirement of salt tolerance in the species. This was also supported by the following features in the salt-tolerant, but not in the -sensitive varieties: (1) highly significant NaCl-induced increase in the activity of PM-H+ATPase, (2) a high constitutive level and NaCl-induced threonine phosphorylation of PM-H+ATPase, necessary to promote its activity, (3) a high constitutive expression of 14-3-3 protein that makes PM-H+ATPase active by binding with the phosphorylated threonine at the C-terminal end, (4) a high constitutive and NaCl-induced expression of SOS1 in roots, and (5) significant NaCl-induced expression of OsCIPK 24, a SOS2 that phosphorylates SOS1. The vacuolar sequestration of Na+ in seedlings was not reflected from the expression pattern of NHX1/NHX1 in response to NaCl. NaCl-induced downregulation of expression of HKTs in roots of Nona Bokra, but upregulation in Pokkali also indicates that their role in salt tolerance in rice could be cultivar specific. The study indicates that consideration of increasing exclusion of Na+ by enhancing the efficiency of SOS1/PM-H+ATPase Na+ exclusion module could be an important aspect in attempting to increase salt tolerance in the rice varieties or cultivars of interest.
Single-cell RNA-seq analysis revealed long-lasting adverse effects of tamoxifen on neurogenesis in prenatal and adult brains
Authors: Lee Chia-Ming , Zhou Liqiang , Liu Jiping , Shi Jiayu , Geng Yanan , Liu Min , Wang Jiaruo , Su Xinjie , Barad Nicholas , Wang Junbang , Sun Yi Eve , Lin Quan
Published: July 2020

Significance

The tamoxifen (TAM)-inducible CreER/LoxP system is one of the most widely used genetic tools that have enabled precise gene manipulation in distinct cell subpopulations at any specific time point and labeling of any cell types for genetic fate mapping. We report that administration of TAM during early stages of cortical neurogenesis inhibits neural progenitor cell proliferation and impaired cortical neurogenesis, dendritic morphogenesis, synaptic density, and gliogenesis in postnatal offspring. By employing single-cell RNA sequencing analysis combined with in vivo and in vitro assays, we found TAM could exert these drastic effects through dysregulating the Wnt-Dmrta2 signaling pathway. This study shows that care must be taken when using the TAM-induced CreER/LoxP system for neural lineage tracing and genetic manipulation studies.
Rational design to control the trade-off between receptor affinity and cooperativity
Authors: Ortega Gabriel , Mariottini Davide , Troina Alessandra , Dahlquist Frederick W. , Ricci Francesco , Plaxco Kevin W.
Published: July 2020

Significance

Cooperative binding is a property by which biomolecular receptors bind multiple-copy molecules of their targets in a highly concerted fashion, improving their responsiveness to small changes in target concentration. This mechanism is ubiquitous in the cell, where it is used to improve transport efficiency, tighten metabolic regulation, and enhance responsiveness to molecular cues. As it often happens in nature, however, this improved responsiveness comes at a cost, inevitably leading to decreased affinity. In our paper, however, we show how the additional binding energy provided by adding new binding sites can be rationally partitioned between improving the responsiveness still further or recovering some of the lost affinity, allowing the design of receptors with highly tailored affinity and cooperativity.
Social distancing responses to COVID-19 emergency declarations strongly differentiated by income
Authors: Weill Joakim A. , Stigler Matthieu , Deschenes Olivier , Springborn Michael R.
Published: July 2020

In the absence of a vaccine, social distancing measures are one of the primary tools to reduce the transmission of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus, which causes coronavirus disease 2019 (COVID-19). We show that social distancing following US state-level emergency declarations substantially varies by income. Using mobility measures derived from mobile device location pings, we find that wealthier areas decreased mobility significantly more than poorer areas, and this general pattern holds across income quantiles, data sources, and mobility measures. Using an event study design focusing on behavior subsequent to state emergency orders, we document a reversal in the ordering of social distancing by income: Wealthy areas went from most mobile before the pandemic to least mobile, while, for multiple measures, the poorest areas went from least mobile to most. Previous research has shown that lower income communities have higher levels of preexisting health conditions and lower access to healthcare. Combining this with our core finding—that lower income communities exhibit less social distancing—suggests a double burden of the COVID-19 pandemic with stark distributional implications.
Speckle patterns for DIC in challenging scenarios: rapid application and impact endurance
Authors: Quino Gustavo , Chen Yanhong , Ramakrishnan Karthik Ram , Martínez-Hergueta Francisca , Zumpano Giuseppe , Pellegrino Antonio , Petrinic Nik
Published: July 2020

Digital image correlation (DIC) is a widely used technique in experimental mechanics for full field measurement of displacements and strains. The subset matching based DIC requires surfaces containing a random pattern. Even though there are several techniques to create random speckle patterns, their applicability is still limited. For instance, traditional methods such as airbrush painting are not suitable in the following challenging scenarios: (i) when time available to produce the speckle pattern is limited and (ii) when dynamic loading conditions trigger peeling of the pattern. The development and application of some novel techniques to address these situations is presented in this paper. The developed techniques make use of commercially available materials such as temporary tattoo paper, adhesives and stamp kits. The presented techniques are shown to be quick, repeatable, consistent and stable even under impact loads and large deformations. Additionally, they offer the possibility to optimise and customise the speckle pattern. The speckling techniques presented in the paper are also versatile and can be quickly applied in a variety of materials.
FRI-based sparse sampling for ultrasonic array signals based on pulse-positive sequence delay synthesis
Authors: Shoupeng Song , Ruixuan Cheng , Mengli Qiao , Hao, Chen , Jiahui Yu
Published: July 2020

Ultrasonic transducer arrays have been widely applied to nondestructive testing due to their high testing efficiency and abundant echo information regarding defects. However, the considerable sampling data generated in array testing greatly restricts the performance levels of the subsequent processes, such as data storage, transmission, and processing. An finite rate of innovation- (FRI) based sparse sampling method has been recently developed, which greatly reduces the volume of sampling data, but only for single-transducer signals. If a transducer array is designed to use this sampling framework, a new problem of an overly complex sampling circuit system will appear. Therefore, this paper develops a novel array signal sparse sampling framework based on the pulse-positive sequence delay synthesis technique, which combines the ultrasonic array analog signals into a one-channel analog signal with a low degree of information freedom for sparse sampling. Although the degree of information freedom of the synthetic signal is greater than that of a single transducer signal, it still satisfies the conditions of signal sparse sampling and the volume of sampling data is still much smaller than that obtained using the traditional Nyquist sampling technique. An example of the experiment using a pure shear wave in the oblique incidence mode on a steel sample is provided, which indicates that eight-channel transducer array signals can be synthesized into one-channel signal, and then, the time delay and amplitude of the defect echo signals can be accurately estimated for each array element from the synthetic-signal sparse sampling data.
Hysteretic behavior of a shape memory alloy-friction damper and seismic performance assessment of cable supported structures and reticulated shells
Authors: Lu Yan , Huang Jin , Han Qinghua , Hao Guangqin
Published: July 2020

This paper proposes a novel shape memory alloy (SMA)-friction damper (SFD) which is composed of friction and SMA energy consumption in parallel. Experiments are carried out to demonstrate the effects of the loading frequency, displacement amplitude and number of SMA wires on the hysteretic behavior of the SFD. Experimental results show that the effect of the loading frequency can be negligible, while the energy consumption increases almost linearly with the displacement amplitude. The increment of the number of SMA wires can significantly increase the stiffness and self-centering capacity to improve the performance of the SFD. Then, a numerical model of the SFD is established by the connector and solid elements in ABAQUS. Finally, a beam string structure, a suspend dome structure, K6 and square-pyramid double-layer spherical reticulated shells with and without SFDs under nine ground motions are analyzed by nonlinear dynamic analysis. For the controlled cable supported structures, the reduction ratio of the peak acceleration and peak displacement reach 46.47% and 52.61%, respectively. And for the controlled double-layer spherical reticulated shells, the reduction ratio of the peak acceleration and peak displacement reach 59.95% and 42.94%, respectively.
A modified one-dimensional constitutive model of pseudoelastic SMAs and its application in simulating the force–deformation relationship of SMA helical springs
Authors: Zhang Zhenhua , Feng Liang , Sheng Piao , Zhang Jingsi , Liu Yihao
Published: July 2020

The Graesser–Cozzarelli constitutive model of shape memory alloys (SMAs) has been widely applied in seismic engineering due to its concise functions with well-defined material parameters. However, this model has some limitations, e.g. it fails to model the hardening behavior of SMAs under relatively large strain amplitudes and the effects of ambient temperature. In this paper, a modified Graesser–Cozzarelli constitutive model of pseudoelastic SMAs is proposed, through consideration of the changes of the elastic moduli of SMAs induced by different martensite fractions, the effects of ambient temperature on the pseudoelastic characteristics, the hardening behavior and the phenomenon of degradation of the pseudoelasticity of SMAs under large strain amplitudes. Furthermore, the modified model was validated by the results of experiments on SMA wires under different strain amplitudes and ambient temperatures. The modified model was then utilized to simulate the force–deformation relationship of SMA helical springs for the first time. In the procedure used to simulate the springs, the torsional and bending moments on the cross-section of the coiled wire of the springs were considered simultaneously, and the effect of the pitch angle was also included. Moreover, the spring simulation procedure was verified by tensile tests of SMA helical springs with complex loading patterns and existing simulated results of the effects of ambient temperature. The research results indicate that the spring simulation procedure based on the modified model can simulate the force–deformation relationship of the springs under different complex loading conditions and ambient temperature reasonably well. Furthermore, the effects of the spring index and the initial height of the springs on the characteristics of the force–deformation relationship were investigated in detail.
Collagen, stiffness, and adhesion: the evolutionary basis of vertebrate mechanobiology
Authors: Tang Vivian W.
Published: July 2020

The emergence of collagen I in vertebrates resulted in a dramatic increase in the stiffness of the extracellular environment, supporting long-range force propagation and the development of low-compliant tissues necessary for the development of vertebrate traits including pressurized circulation and renal filtration. Vertebrates have also evolved integrins that can bind to collagens, resulting in the generation of higher tension and more efficient force transmission in the extracellular matrix. The stiffer environment provides an opportunity for the vertebrates to create new structures such as the stress fibers, new cell types such as endothelial cells, new developmental processes such as neural crest delamination, and new tissue organizations such as the blood–brain barrier. Molecular players found only in vertebrates allow the modification of conserved mechanisms as well as the design of novel strategies that can better serve the physiological needs of the vertebrates. These innovations collectively contribute to novel morphogenetic behaviors and unprecedented increases in the complexities of tissue mechanics and functions.
Critique
Authors: Blake Charlie
Published: July 2020

From its emergence and early evolution in and through the writings of Immanuel Kant, Ludwig Feuerbach, and Karl Marx, critique established its parameters very early on as both porous and dynamic. Critique has always been, in this sense, mutable, directed, and both multidisciplinary and transdisciplinary, and this very fluidity and flexibility of its processes are possibly among the central reasons for its continuous relevance even when it has been dismantled, rebuffed, and attacked for embodying traits, from gender bias to Eurocentrism to neuro-normativity, that seem to indicate the very opposite of that flexibility. Indeed, once it is examined closely as an apparatus, the mechanism of critique will invariably reveal itself as having always contained the tools for its own opposition and even the tools for its own destruction. Critique has in this way always implied both its generality as a form and autocritique as an essential part of its process. For the past two centuries this general, self-reflective, and self-dismantling quality has led to its constant reinvention and re-adaptation by a wide range of thinkers and writers and across a broad range of disciplines.

In the case of literature and literary theory, its role can often best be grasped as that of a meta-discourse in which the nature and purpose of literary criticism is shadowed, reflected upon, and performed. From this perspective, from the 18th-century origins of critique in its gestation in the fields of theology and literary criticism to its formalization by Kant, the literary expression of critique has always been bound up with debates over the function of literary texts, their history, their production, their consumption, and their critical evaluation. In the early 21st century, having evolved from its beginnings through and alongside various forms of anticritique in the 20th century, critique now finds itself in an age that favors some variant or other of postcritique. It remains to be seen whether this tendency, which suggests its obsolescence and superseding, marks the end of critique as some would wish or merely its latest metamorphosis and diversification in response to the multivalent pressures of digital acceleration and ecological crisis. Whatever path or paths contemporary judgment on this question may follow, critique as the name of a series of techniques and operations guided by a desire for certain ends is likely to remain one of the most consistent ways of surveying any particular field of intellectual endeavor and the relations between adjacent or even divergent fields in terms of their commonalities and differences. As Kant and Voltaire understood so well of their own age, modernity is characterized in the first instance by its will to criticism and then by the systematic criticism of the conditions for that criticism. By the same token now in late or post- or neo-modernity, if contemporary conversations about literature and its pleasures, challenges, study, and criticism require an overview, then some version of critique or its legacy will undoubtedly still come into play.
Disability Studies
Authors: McRuer Robert
Published: July 2020

Disability studies is an interdisciplinary mode of inquiry that flourished beginning in the late 20th century. Disability studies challenges the singularity of dominant models of disability, particularly the medical model that would reduce disability to diagnosis, loss, or lack, and that would insist on cure as the only viable approach to apprehending disability. Disability studies pluralizes ways of thinking about disability, and bodily, mental, or behavioral atypicality in general; it simultaneously questions the ways in which able-bodiedness has been made to appear natural and universal. Disability studies is an analytic that attends to how disability and ability are represented in language and in a wide range of cultural texts, and it is particularly attuned to the ways in which power relations in a culture of normalization have generally subordinated disabled people, particularly in capitalist systems that demand productive and efficient laborers. Disability studies is actively intersectional, drawing on feminist theory, critical race theory, queer theory, and other analytics to consider how gender, race, sexuality, and disability are co-constitutive, always implicated in each other.

Crip theory has emerged as a particular mode of doing disability studies that draws on the pride and defiance of crip culture, art, and activism, with crip itself marking both a reclamation of a term designed to wound or demean and as a marker of the fact that bodies and minds do not fit neatly within or beneath a historical able-bodied/disabled binary. “To crip,” as a critical process, entails recognizing how certain bodily and mental experiences have been made pathological, deviant, or perverse and how such experiences have subsequently been marginalized or invisibilized. Queer of color critique, which is arguably at the absolute center of the project of queer theory, shares a great deal with crip theory, as it consistently points outward to the relations of power that constitute and reconstitute the social. Queer of color critique focuses on processes of racialization and gendering that make certain groups perverse or pathological. Although the ways in which this queer of color project overlaps significantly with disability studies and crip theory have not always been acknowledged, vibrant modes of crip of color critique have emerged in the 21st century, making explicit the connections.
Arabic Literary Theory
Authors: Harb Lara
Published: July 2020

The Arabic language has a rich history of literary criticism and theory, starting from the 8th century ce up to the 21st century. This literary criticism and theory engages with a poetic tradition that dates back to pre-Islamic times. The inquiry into literary quality was motivated by an interest in evaluating poetry, a general concern with eloquent speech, whether in verse or prose, and by the desire to articulate the beauty of the Quran. The transmission of Aristotle’s Poetics into Arabic also spurred interest in the poetic, particularly in Arabic philosophy. The study of eloquence crystallized into a standardized science by the 13th century ce, with branches focusing on (1) the role of syntax in literary beauty (the science of meanings); (2) simile, metaphor, and metonymy (the science of elucidation); and (3) rhetorical figures (the science of rhetorical figures).

The aesthetic developed in the early criticism of the 9th and 10th centuries was concerned with articulating the merits of an idealized classical style of pre-Islamic poetry, from which the “modern” poets of the early Abbasid period diverged. This classically oriented aesthetic was dominated by a concern with the truthfulness and naturalness of poetry, typical of the style of the “ancients,” on the one hand, and the limits of unrealistic imagery and affected artificiality, which characterized the more ornate modern Abbasid style, on the other. This binary outlook shifted after the 10th century, however, to an aesthetic of wonder. A theory of aesthetic experience began to develop, therefore, which was based on the ability of poetic language to evoke wonder in the recipient. As a result, wonder-enhancing characteristics such as strangeness, the unexpected, and the rare became essential components of aesthetic judgment. Moreover, the ability of language to make meaning manifest in ways that allow for an experience of discovery and hence wonder, became the foundation of aesthetic inquiry in post-10th century Arabic literary theory.
Managing Third Sector Organizations
Authors: Murdock Alex , Barber Stephen
Published: July 2020

What is the state of what can be described as management in the third sector? At its heart, it discusses the long-held assertion that these organizations are reluctant to accept the need for ‘management’. After all, what makes third sector organizations different, by their own estimation, from their commercial equivalents is the deeply embedded concepts of mission and values together with a distinctly complex stakeholder environment.

For all that, there are also “commercial” pressures and an instinct for survival. To serve the mission necessarily needs resources. And there is a perennial tension in high-level decision-making between delivery of the mission and maintaining solvency. Third-sector organizations, like any other, are innately concerned with their own sustainability. It is here that the analysis is located and there is an opportunity to examine the topic theoretically and empirically. By introducing the concept of the “Management See-Saw” to illustrate the competing drivers of values and commercialism before exploring these identified pressures through the lens of three real-life vignettes, it is possible to appreciate the current state of play.

Given all this, it is important for modern organizations to be able to measure value and impact. From a managerial perspective, the reality needs to be acknowledged that this environment is complex and multi-layered. In drawing the strands together, the discussion concludes by illustrating the importance of leadership in the sector, which is a powerful indicator of effectiveness.

Nevertheless, with a focus on management, the core contention is that management remains undervalued in the third sector. That said, commercial focus can increasingly be identified and the longer term trend is squarely in this direction.
African Biomass Burning and Its Atmospheric Impacts
Authors: Ichoku Charles
Published: July 2020

Biomass burning is widespread in sub-Saharan Africa, which harbors more than half of global biomass burning activity. These African open fires are mostly induced by humans for various purposes, ranging from agricultural land clearing and residue burning to deforestation. They affect a wide variety of land ecosystems, including forests, woodlands, shrublands, savannas, grasslands, and croplands. Satellite observations show that fires are distributed almost equally between the northern and southern hemispheres of sub-Saharan Africa, with a dipole-type annual distribution pattern, peaking during the dry (winter) season of either hemisphere. The widespread nature of African biomass burning and the tremendous amounts of particulate and gas-phase emissions the fires produce have been shown to affect a variety of processes that ultimately impact the earth’s atmospheric composition and chemistry, air quality, water cycle, and climate in a significant manner. However, there is still a high level of uncertainty in the quantitative characterization of biomass burning, and its emissions and impacts in Africa and globally. These uncertainties can be potentially alleviated through improvements in the spatial and temporal resolutions of satellite observations, numerical modeling and data assimilation, complemented by occasional field campaigns. In addition, there is great need for the general public, policy makers, and funding organizations within Africa to recognize the seriousness of uncontrolled biomass burning and its potential consequences, in order to bring the necessary human and financial resources to bear on essential policies and scientific research activities that can effectively address the threats posed by the combined adverse influences of the changing climate, biomass burning, and other environmental challenges in sub-Saharan Africa.
Measuring Attitudes Toward LGBT Individuals: Theoretical and Practical Considerations
Authors: Steffens Melanie C. , Preuß Sabine
Published: July 2020

Over the last decades, in many so-called Western countries, the social, political, and legal standing of lesbians, gay men, and bisexual and trans* individuals (henceforth, LGBT* individuals) has considerably improved, and concurrently, attitudes toward these groups have become more positive. Consequently, people are aware that blatantly prejudiced statements are less socially accepted, and thus, negative attitudes toward LGBT* individuals (also referred to as antigay attitudes, sexual prejudice, or homonegativity) and their rights need to be measured in more subtle ways than previously. At the same time, discrimination and brutal hate crimes toward LGBT* individuals still exist (e.g., Orlando shooting, torture of gay men in Chechnya). Attitudes are one of the best predictors of overt behavior. Thus, examining attitudes toward LGBT* individuals in an adequate way helps to predict discriminatory behavior, to identify underlying processes, and to develop interventions to reduce negative attitudes and thus, ultimately, hate crimes.

The concept of attitudes is theoretically postulated to consist of three components (i.e., the cognitive, affective, and behavioral attitude components). Further, explicit and implicit attitude measures are distinguished. Explicit measures directly ask participants to state their opinions regarding the attitude object and are thus transparent, they require awareness, and they are subject to social desirability. In contrast, implicit measures infer attitudes indirectly from observed behavior, typically from reaction times in different computer-assisted tasks; they are therefore less transparent, they do not require awareness, and they are less prone to socially desirable responding. With regard to explicit attitude measures, old-fashioned and modern forms of prejudice have been distinguished. When it comes to measuring LGBT* attitudes, measures should differentiate between attitudes toward different sexual minorities (as well as their rights). So far, research has mostly focused on lesbians and gay men; however, there is increasing interest in attitudes toward bisexual and trans* individuals. Also, attitude measures need to be able to adequately capture attitudes of more or less prejudiced segments of society. To measure attitudes toward sexual minorities adequately, the attitude measure needs to fulfill several methodological criteria (i.e., to be psychometrically sound, which means being reliable and valid). In order to demonstrate the quality of an attitude measure, it is essential to know the relationship between scores on the measure and important variables that are known to be related to LGBT* attitudes. Different measures for LGBT* attitudes exist; which one is used should depend on the (research) purpose.