bluuebunny/crossref_metadata_2025 huggingface dataset:
A novel recursive approach for online identification of continuous‐time switched nonlinear systems
Authors: Du Yingwei , Liu Fangzhou , Qiu Jianbin , Buss Martin
Published: July 2021

This article focuses on the identification of switched nonlinear systems, which are characterized as a collection of nonlinear dynamical systems. Each nonlinear subsystem is activated by a discrete‐valued variable (switching signal). Specifically, we consider the continuous‐time switched nonlinear systems in the state‐space form in our article. The identification of switched nonlinear systems amounts to simultaneous estimation of the switching signal and the nonlinear dynamic subsystems via all measured state‐input vectors. However, the problem is challenging and generally requires a large computational complexity to be solved. In this article, we propose a novel online approach to address the identification problem of switched nonlinear systems, which is capable to handle the measured state‐input vectors in sequence. In particular, the principle used for estimating the switching signal is developed based on the subspace method. Subsequently, the integral concurrent learning identifier is extended to identify the dynamics of each subsystem recursively. The effectiveness of the proposed identification approach is demonstrated via simulation results.
Hybrid threshold combining and maximum ratio combining model for satellite communication over composite Rayleigh and Rician fading channel
Authors: Ahmed Wasiu Akande , Wu Falin , Agbaje Ganiy Ishola , Sikder Muhammad Abdul Alim , Ojedokun Isaac Adewale
Published: July 2021

Communication through satellite is of great task and importance especially in the world of telecommunication infrastructure. It plays a leading role for future communication systems. However, the performance of the satellite communication system is dominated by the channel conditions overwhelmed by multipath fading and ionospheric scintillation effects. Maximum ratio combining (MRC) previously used to tackle this problem is characterized with hardware complexity resulted in long processing time, while threshold combining (TC) with simple hardware display poor performance. Thus, evaluation of hybrid TC‐MRC, with closed‐form expression over composite Rayleigh and Rician fading channel is necessary. In this paper, TC and MRC are combined to improve the signal quality and performance. The data are modulated using M‐ary quadrature amplitude modulation and transmitted over the combined effects. The received signals at varying paths are scanned to select the best paths. A mathematical expression using the probability density function of composite Rayleigh and Rician fading channel for mean integrated square error (MISE) is derived. The model is efficiently simulated and the performance is estimated. The results show that the hybrid TC‐MRC model achieves lower MISE and processing time compared to threshold combiner and even maximum ratio combiner, and thereby enhance the performance of the satellite communication system.
Developing Longer‐Lived Single Molecule Junctions with a Functional Flexible Electrode
Authors: Huang Mingzhu , Yu Lei , Zhang Mingyang , Wang Zhe , Xiao Bohuai , Liu Yichong , He Jin , Chang Shuai
Published: July 2021

Creating single‐molecule junctions with a long‐lived lifetime at room temperature is an open challenge. Finding simple and efficient approaches to increase the durability of single‐molecule junction is also of practical value in molecular electronics. Here it is shown that a flexible gold‐coated nanopipette electrode can be utilized in scanning tunneling microscope (STM) break‐junction measurements to efficiently enhance the stability of molecular junctions by comparing with the measurements using conventional solid gold probes. The stabilizing effect of the flexible electrode displays anchor group dependence, which increases with the binding energy between the anchor group and gold. An empirical model is proposed and shows that the flexible electrode could promote stable binding geometries at the gold‐molecule interface and slow down the junction breakage caused by the external perturbations, thereby extending the junction lifetime. Finally, it is demonstrated for the first time that the internal conduit of the flexible STM tip can be utilized for the controlled molecule delivery and molecular junction formation.
Electroplated Copper Metal Contacts on Perovskite Solar Cells
Authors: Hatt Thibaud , Kabakli Özde Ş. , Schulze Patricia S. C. , Richter Armin , Glunz Stefan W. , Glatthaar Markus , Goldschmidt Jan Christoph , Bartsch Jonas
Published: July 2021

Electroplated copper contacts on small‐area single‐junction perovskite solar cells (PSCs) using an atomic layer deposited (ALD) Al2O3 masking layer on ITO are demonstrated for the first time. The photoconversion efficiency of ≈11% after manufacturing the Cu contacts confirms that PSCs can survive the wet‐chemical plating process. From the successful realization of plated contact fingers, the creation of an electrical contact between the Cu electrode and the ITO on the FA0.75Cs0.25Pb(I0.8Br0.2)3 perovskite absorber is inferred. Furthermore, scanning electron microscopy (SEM) with energy‐dispersive X‐ray (EDX) analysis shows the formation of a compact interface between ITO and plated Cu. An additional plating approach, using self‐passivated aluminum as mask, allows to produce well‐defined 30 μm wide Cu contacts on the PSC. Such a plating process allows for plating a low‐resistive Cu grid simultaneously on both sides of a perovskite silicon heterojunction tandem solar cell with TCO, independent of substrate size.
Identities in/out of physics and the politics of recognition
Authors: Avraamidou Lucy
Published: July 2021

Framed within intersectionality, this multiple case study explores women's participation in physics through the construct of physics identity and with a focus on recognition. The study is drawn upon an empirical life‐history exploration of three women: a native to Northwestern Europe, late‐career white woman and two immigrant women to Northwestern Europe, one is an undergraduate student of color, and the other, an early career Muslim woman. The data for this study were collected through multiple, semistructured, interviews in a period of 2 years, which were analyzed using a constant comparative method. Collectively, the three life‐histories tell stories of otherness, persistence, hope, and failure and they elucidate the kinds of identities that are deemed “in‐place” and “out‐of‐place” in physics. They showcase how the three women authored multiple identities that simply co‐existed for them, while for others were seen as conflicting and caused misrecognition. The findings point to four main insights: (a) recognition is neither linear nor binary and it comes in many different forms that range from explicit encouragement to no opposition; (b) it is drawn upon various sources including ones in the early years of life: family, school teachers, university instructor, students, and social community; (c) it is culture‐dependent and as such, it is influenced by factors on multiple levels, including cultural and gender stereotypes, organizational policies, racism, sexism, classicism, and other forms of discrimination. The implications of these findings speak to the need for: (a) systemic programs on how women are recognized by others and which seek to widen and diversify physics environments from the school level to the professional level; (b) research exploration of the politics of recognition and how they perpetuate the underrepresentation of women in physics; and, (c) disrupting monolithic theorizations of recognition and adopting intersectional approaches to exploring physics identity that value women's personal histories, subjectivities, and positionalities.
MiR‐186‐5p suppresses cell migration, invasion, and epithelial mesenchymal transition in bladder cancer by targeting RAB27A/B
Authors: Zhang Qianjin , Hao Lin , Shen Zhiyong , Wang Fengye , Han Conghui
Published: July 2021

Bladder cancer (BCa) is a common malignancy in the urinary system. Ras‐related protein Rab‐27A (RAB27A) and Ras‐related protein Rab‐27B (RAB27B) have been verified to be closely related to the development of many tumors. Since the role of both RAB27A and RAB27B in BCa have not been reported, we intended to explore the function and mechanism of RAB27A and RAB27B in BCa development. Reverse transcription quantitative polymerase chain reaction revealed that RAB27A/B showed high expression in BCa tissues and cells. Cell counting kit‐8, wound healing and Transwell assays as well as western blot analyses revealed that silencing RAB27A/B suppressed BCa cell proliferation, migration and invasion as well as the epithelial‐mesenchymal transition (EMT) process. Based on bioinformatics analysis and our experiments, microRNA‐186‐5p (miR‐186‐5p) was found to be the upstream miRNA of RAB27A/B in BCa. MiR‐186‐5p expression was significantly downregulated in BCa cells and tissues. MiR‐186‐5p directly targeted the 3′‐untranslated region (3′‐UTR) of RAB27A/B and downregulated both mRNA and protein levels of RAB27A/B in BCa cells. MiR‐186‐5p overexpression suppressed BCa cell proliferation, migration and invasion as well as the EMT process in vitro and inhibited tumor growth in vivo. Overexpressing RAB27A/B rescued the inhibitory effect of miR‐186‐5p on malignant phenotypes of BCa cells. Furthermore, miR‐186‐5p inactivated the phosphatidylinositol 3‐Kinase (PI3K)/mitogen‐activated protein kinase (MAPK) signaling pathway by downregulating the expression of RAB27A/B, as shown in western blot analysis. Overall, miR‐186‐5p suppressed BCa cell proliferation, migration, invasion and EMT process and inhibited xenograft tumor growth by targeting RAB27A/B to inactivate the PI3K/MAPK signaling.
Demethoxycurcumin induces apoptosis in HER2 overexpressing bladder cancer cells through degradation of HER2 and inhibiting the PI3K/Akt pathway
Authors: Kao Chien‐Chang , Cheng Yi‐Ching , Yang Ming‐Hsin , Cha Tai‐Lung , Sun Guang‐Huan , Ho Chi‐Tang , Lin Ying‐Chao , Wang Hao‐Kuang , Wu Sheng‐Tang , Way Tzong‐Der
Published: July 2021

Bladder cancer is the most common malignancy of the urinary tract and arising from the epithelial lining of the urinary bladder. Resistance to cytotoxic therapies is associated with overexpression of oncogenic proteins; including HER2, and Akt in chemotherapy resistance of bladder cancer. Various studies demonstrated that curcuminoids, the most important active phenolic compounds of turmeric (Curcuma longa), have anti‐tumor activities in a wide range of human malignant cell lines. The aim of this study is to evaluate whether curcuminoids (curcumin, demethoxycurcumin (DMC), and bisdemethoxycurcumin) could repress the expression of HER2 in HER2‐overexpressing bladder cancer cells. Among the test compounds, DMC significantly suppressed the expression of HER2, and preferentially inhibited cell proliferation and induced apoptosis in HER2‐overexpressing bladder cancer cells. DMC decreases HER2 level through inhibiting the interaction of HER2 and Hsp90. Our study also indicated that DMC showed additive activity in combination with chemotherapeutic agents, including paclitaxel and cisplatin. These findings show that DMC should be developed further as a new antitumor drug candidate for treatment of HER2‐overexpressing bladder cancer.
Non‐thymoma‐associated exfoliative dermatitis in a European shorthair cat: A case report
Authors: Szczepanik Marcin , Wilkołek Piotr , Śmiech Anna , Kalisz Grzegorz
Published: July 2021

The current case report presents a case of non‐thymoma‐associated exfoliative dermatitis in an 8‐year‐old European Shorthair female cat. The animal displayed extensive alopecia and excessive peeling of the epidermis. There were no other apparent disorders, except for the skin lesions. Roentgenographic and sonographic examinations, complete blood count and blood serum chemistry analyses, and skin biopsy were performed. The histopathological investigation revealed hyperkeratosis of the epidermis and the infiltration of lymphocytes and macrophages at the dermal‐epidermal junction around the hair follicles and sebaceous glands. Moreover, edema of the basal layer and melanin migration from the epidermis to the dermis were observed. The patient underwent treatment with immunosuppressive doses of prednisolone, antibiotic therapy, and baths in anti‐seborrheic shampoos and displayed resolution. However, recurrence was observed after one month. Consequently, the patient received cyclosporine A, in addition to the aforementioned treatment and the lesions resolved without relapse.
Comparison of mtDNA control region among descendant breeds of the extinct Zaupel sheep revealed haplogroup C and D in Central Europe
Authors: Gáspárdy András , Berger Beate , Zabavnik‐Piano Jelka , Kovács Endre , Annus Kata , Zenke Petra , Sáfár László , Maróti‐Agóts Ákos
Published: July 2021

The consideration of the descendance is indispensable in the preservation of endangered animal breeds.

The authors compared mitochondrial DNA (mtDNA) control region sequence in three descendant breeds of the extinct Zaupel sheep, firstly. Their investigation was carried out in order to prove the common origin of Waldschaf (Austria), Bovec sheep (Slovenia) and Cikta (Hungary).

A total of 118 biological samples were taken from non‐related representatives of the three breeds between 2015 and 2017. A newly designed primer pair was also used to amplify the segment (1180 bp) to be tested.

The total number of haplotypes in the whole study population was 49. The majority of which fell into haplogroup B. The significant negative value of the Fu's Fs statistic (Fs statistic = −3.296, p = 0.013) based on haplotype frequencies demonstrated a moderate foreign gene flow. As a novel observation haplogroups C and D appeared in Cikta and Bovec sheep, respectively. The Tajima D‐test value in the entire study population was −0.914 (p > 0.10), meaning that the separation of the three descendant breeds did not cause genetic drift, these are collectively in genetic equilibrium.

The genetic information confirmed the common origin of the breeds known from the breed history.
Low occurrence of Salmonella spp. in wild birds from a Swiss rehabilitation centre
Authors: Vogler Barbara R. , Zurfluh Katrin , Mattmann Prisca , Schmitt Kira , Albini Sarah
Published: July 2021

Background

Salmonella are bacteria of the family Enterobacteriaceae with a wide host range. Infection in birds causes subclinical disease to mass mortality events. Wild birds may act as healthy carriers posing a hazard to livestock and humans. The present study investigated the occurrence of Salmonella in wild birds admitted to a rehabilitation centre in order to assess the exposure of the staff to this zoonotic pathogen.

Methods

Faecal swabs of 552 avian patients (68 species) were collected over the course of 12 months. Each sample was propagated in enrichment broth and subsequently incubated on a RAPID'Salmonella plate. Salmonella isolates were serotyped, and antimicrobial susceptibility testing was performed.

Results

Six Salmonella enterica subsp. enterica serovar Typhimurium (S. Typhimurium) and 1 S. Schleissheim were detected; all were pansusceptible to the antibiotics tested.

Conclusion

Despite the low positive rate in the tested population, the authors recommend applying protective equipment and hygiene measures when handling wild birds.
The Universal Thermal Climate Index as an Operational Forecasting Tool of Human Biometeorological Conditions in Europe
Authors: Di Napoli Claudia , Messeri Alessandro , Novák Martin , Rio João , Wieczorek Joanna , Morabito Marco , Silva Pedro , Crisci Alfonso , Pappenberger Florian
Published: July 2021

In operational weather forecasting standard environmental parameters, such as air temperature and humidity, are traditionally used to predict thermal conditions in the future. These parameters, however, are not enough to describe the thermal stress induced by the outdoor environment to the human body as they neglect the human heat budget and personal characteristics (e.g. clothing). The Universal Thermal Climate Index (UTCI) overcomes these limitations by using an advanced thermo-physiological model coupled with a state-of-the-art clothing model. Several systems have been recently developed to operationally forecast human biometeorological conditions via the UTCI, i.e. by computing UTCI from the forecasts of air temperature, humidity, wind speed and radiation as provided by numerical weather prediction models. Here we describe the UTCI-based forecasting systems developed in Czech Republic, Italy, Poland, Portugal and at the pan-European scale. Their characteristics are illustrated and their potential as warning systems for thermal hazards discussed.
A bestiary of black holes on the conifold with fluxes
Authors: Buchel Alex
Published: July 2021

Abstract

We present a comprehensive analysis of the black holes on warped deformed conifold with fluxes in Type IIB supergravity. These black holes realize the holographic dual to thermal states of the $$ \mathcal{N} $$
N
= 1 supersymmetric SU(N) × SU(N + M) cascading gauge theory of Klebanov et al. [1, 2] on round S3. There are three distinct mass scales in the theory: the strong coupling scale Λ of the cascading gauge theory, the compactification scale μ = 1/L3 (related to the S3 radius L3) and the temperature T of a thermal state. Depending on Λ, μ and T, there is an intricate pattern of confinement/deconfinement (Hawking-Page) and the chiral symmetry breaking phase transitions. In the S3 → ℝ3 decompactification limit, i.e., μ → 0, we recover the Klebanov-Tseytlin [3] and the Klebanov-Strassler [4] black branes.
Multi-spin soft bootstrap and scalar-vector Galileon
Authors: Kampf Karol , Novotný Jiří , Přeučil Filip , Trnka Jaroslav
Published: July 2021

Abstract

We use the amplitude soft bootstrap method to explore the space of effective field theories (EFT) of massless vectors and scalars. It is known that demanding vanishing soft limits fixes uniquely a special class of EFTs: non-linear sigma model, scalar Galileon and Born-Infeld theories. Based on the amplitudes analysis, we conjecture no-go theorems for higher-derivative vector theories and theories with coupled vectors and scalars. We then allow for more general soft theorems where the non-trivial part of the soft limit of the (n+1)-pt amplitude is equal to a linear combination of n-pt amplitudes. We derive the form of these soft theorems for general power-counting and spins of particles and use it as an input into the soft bootstrap method in the case of Galileon power-counting and coupled scalar-vector theories. We show that this unifies the description of existing Galileon theories and leads us to the discovery of a new exceptional theory: Special scalar-vector Galileon.
Lüscher-corrections for 1-particle form-factors in non-diagonally scattering integrable quantum field theories
Authors: Hegedűs Árpád
Published: July 2021

Abstract

In this paper we derive from field theory a Lüscher-formula, which gives the leading exponentially small in volume corrections to the 1-particle form-factors in non-diagonally scattering integrable quantum field theories. Our final formula is expressed in terms of appropriate expressions of 1- and 3-particle form-factors, and can be considered as the generalization of previous results obtained for diagonally scattering bosonic integrable quantum field theories. Since our formulas are also valid for fermions and operators with non-zero Lorentz-spin, we demonstrated our results in the Massive Thirring Model, and checked our formula against 1-loop perturbation theory finding perfect agreement.
High-pressure behavior of disordered kesterite-type Cu2ZnSnS4
Authors: Efthimiopoulos Ilias , Küllmey Tim , Speziale Sergio , Pakhomova Anna S. , Quennet Marcel , Paulus Beate , Ritscher Anna , Lerch Martin
Published: July 2021

We have investigated the high-pressure structural and vibrational behavior of the disordered kesterite-type Cu2ZnSnS4 compound at ambient temperature. Our experimental and theoretical investigations have revealed a clear structural transition to a GeSb-type phase close to 15 GPa, a tetragonally distorted variant of the NaCl-type phase. The latter transformation is accompanied by a cationic coordination increase from fourfold to sixfold with respect to the sulfur anions. In addition, a change in the compressibility rate was detected at about 8 GPa within the pressure stability range of the disordered kesterite-type phase. Upon decompression, a disordered zinc blende/sphalerite structure is recovered. We discuss our findings in close conjunction with our recent high-pressure work on the ordered Cu2ZnSnS4 modification.
Counting Salem Numbers of Arithmetic Hyperbolic 3-Orbifolds
Authors: Belolipetsky Mikhail , Lalín Matilde , Murillo Plinio G. P. , Thompson Lola
Published: July 2021

It is known that the lengths of closed geodesics of an arithmetic hyperbolic orbifold are related to Salem numbers. We initiate a quantitative study of this phenomenon. We show that any non-compact arithmetic 3-dimensional orbifold defines $$c Q^{1/2} + O(Q^{1/4})$$

c

Q

1
/
2

+
O

(

Q

1
/
4

)

square-rootable Salem numbers of degree 4 which are less than or equal to Q. This quantity can be compared to the total number of such Salem numbers, which is shown to be asymptotic to $$\frac{4}{3}Q^{3/2}+O(Q)$$

4
3

Q

3
/
2

+
O

(
Q
)

. Assuming the gap conjecture of Marklof, we can extend these results to compact arithmetic 3-orbifolds. As an application, we obtain lower bounds for the strong exponential growth of mean multiplicities in the geodesic spectrum of non-compact even dimensional arithmetic orbifolds. Previously, such lower bounds had only been obtained in dimensions 2 and 3.
Raman imaging of Micrasterias: new insights into shape formation
Authors: Felhofer Martin , Mayr Konrad , Lütz-Meindl Ursula , Gierlinger Notburga
Published: July 2021

The algaeMicrasteriaswith its star-shaped cell pattern is a perfect unicellular model system to study morphogenesis. How the indentations are formed in the primary cell wall at exactly defined areas puzzled scientists for decades, and they searched for chemical differences in the primary wall of the extending tips compared to the resting indents. We now tackled the question by Raman imaging and scanned in situ Micrasteriascells at different stages of development. Thousands of Raman spectra were acquired from the mother cell and the developing semicell to calculate chemical images based on an algorithm finding the most different Raman spectra. Each of those spectra had characteristic Raman bands, which were assigned to molecular vibrations of BaSO4, proteins, lipids, starch, and plant cell wall carbohydrates. Visualizing the cell wall carbohydrates revealed a cell wall thickening at the indentations of the primary cell wall of the growing semicell and uniplanar orientation of the cellulose microfibrils to the cell surface in the secondary cell wall. Crystalline cellulose dominated in the secondary cell wall spectra, while in the primary cell wall spectra, also xyloglucan and pectin were reflected. Spectral differences between the indent and tip region of the primary cell wall were scarce, but a spectral mixing approach pointed to more cellulose fibrils deposited in the indent region. Therefore, we suggest that cell wall thickening together with a denser network of cellulose microfibrils stiffens the cell wall at the indent and induces different cell wall extensibility to shape the lobes.
A note on organizational structure and environmental liability
Authors: Franckx Laurent , de Vries Frans P. , White Ben
Published: July 2021

This paper employs a multi-task principal-agent model to examine how a corporation’s organizational structure and liability rules for environmental damages affect the incentive schemes offered to managers. We derive environmental liability rules for risk averse managers under two alternative organizational structures: a product-based organization (PBO) and functional-based organization (FBO). For a PBO, it is shown that efficiency is independent of whether the firm or managers are liable for environmental damages; in a FBO it is optimal either to hold the firm liable for environmental damages or, equivalently, to only hold the environmental managers liable for damages. It is also shown that the two organizational structures are equally efficient when there is no correlation between environmental damages from products and no spillover between managerial effort across products or functions. Numerical results further reveal that beneficial spillovers between functions for the same product favours a PBO over a FBO; beneficial spillovers across functions favours a FBO.
Pathways to performance in undergraduate medical students: role of conscientiousness and the perceived educational environment
Authors: Schrempft S. , Piumatti G. , Gerbase M. W. , Baroffio A.
Published: July 2021

This study examined conscientiousness and the perceived educational environment as independent and interactive predictors of medical students’ performance within Biggs’ theoretical model of learning. Conscientiousness, the perceived educational environment, and learning approaches were assessed at the beginning of the third year in 268 medical students at the University of Geneva, Switzerland. Performance was examined at the end of the third year via a computer-based assessment (CBA) and the Objective Structured Clinical Examination (OSCE). Path analysis was used to test the proposed model, whereby conscientiousness and the perceived educational environment predicted performance directly and indirectly via students’ learning approaches. A second model included interaction effects. The proposed model provided the best fit and explained 45% of the variance in CBA performance, and 23% of the variance in OSCE performance. Conscientiousness positively predicted CBA performance directly (β = 0.19, p < 0.001) and indirectly via a deep learning approach (β = 0.05, p = 0.012). The perceived educational environment positively predicted CBA performance indirectly only (β = 0.02, p = 0.011). Neither conscientiousness nor the perceived educational environment predicted OSCE performance. Model 2 had acceptable, but less optimal fit. In this model, there was a significant cross-over interaction effect (β = 0.16, p < 0.01): conscientiousness positively predicted OSCE performance when perceptions of the educational environment were the most positive, but negatively predicted performance when perceptions were the least positive. The findings suggest that both conscientiousness and perceptions of the educational environment predict CBA performance. Research should further examine interactions between personality traits and the medical school environment to inform strategies aimed at improving OSCE performance.
A Pilot Study of a Mobile Intervention to Support Mental Health and Adherence Among Adolescents Living with HIV in Western Kenya
Authors: Chory Ashley , Callen Grant , Nyandiko Winstone , Njoroge Tabitha , Ashimosi Celestine , Aluoch Josephine , Scanlon Michael , McAteer Carole , Apondi Edith , Vreeman Rachel
Published: July 2021

Mobile technologies represent potentially novel and scalable intervention delivery platforms for adolescents living with HIV (ALWH) in low- and middle-income countries. We conducted a prospective, mixed methods pilot study to evaluate the acceptability and feasibility of the WhatsApp® platform to deliver individual counseling services and facilitate peer support for ALWH in western Kenya. Thirty ALWH (17 female, mean age 15.4) on ART, engaged in HIV care and aware of their status, were enrolled. After 6 months, participants described their experiences with the intervention. Treatment adherence, stigma, and mental and behavioral health were assessed prospectively. Participants reported overall positive experiences and indicated that the platform encouraged peer network development. They endorsed potential benefits for treatment adherence, stigma reduction, and mental and behavioral health. All participants supported intervention expansion. In western Kenya, WhatsApp® was an acceptable and feasible platform for mobile counseling and peer support for ALWH.
Modelling the nonlinear static response of a 2-storey URM benchmark case study: comparison among different modelling strategies using two- and three-dimensional elements
Authors: Cannizzaro Francesco , Castellazzi Giovanni , Grillanda Nicola , Pantò Bartolomeo , Petracca Massimo
Published: July 2021

This paper aims at comparing the use of different software environments for the study of a simple unreinforced masonry building through nonlinear static analyses. The presented results are part of a wider research project conducted within the ReLUIS consortium, and specifically within a research task whose purpose is providing practitioners with results and tools for an aware employment of commercial software packages for modelling masonry structures. In this study one of the benchmark structures of the research program is analysed; a two-story building characterized by rigid horizontal diaphragms, considering different configurations in terms of openings arrangements and effectiveness of ring beams, is subjected to seismic load conditions. Software packages considering two- and three- dimensional structural models are employed, and the obtained results are compared in terms of capacity curves and collapse mechanisms. One of the critical aspects on the basic assumptions made by software in terms of way to apply the horizontal loads is further investigated. In addition, the role of the shear strength is analysed correlating the mechanical properties to be adopted with micro- and macro- models. The considered models present very different features, and the analogies and differences obtained in the results are critically interpreted in view of the different hypotheses made by the software tools in terms of modelling strategies and adopted constitutive laws.
Sequential optimality conditions for cardinality-constrained optimization problems with applications
Authors: Kanzow Christian , Raharja Andreas B. , Schwartz Alexandra
Published: July 2021

Recently, a new approach to tackle cardinality-constrained optimization problems based on a continuous reformulation of the problem was proposed. Following this approach, we derive a problem-tailored sequential optimality condition, which is satisfied at every local minimizer without requiring any constraint qualification. We relate this condition to an existing M-type stationary concept by introducing a weak sequential constraint qualification based on a cone-continuity property. Finally, we present two algorithmic applications: We improve existing results for a known regularization method by proving that it generates limit points satisfying the aforementioned optimality conditions even if the subproblems are only solved inexactly. And we show that, under a suitable Kurdyka–Łojasiewicz-type assumption, any limit point of a standard (safeguarded) multiplier penalty method applied directly to the reformulated problem also satisfies the optimality condition. These results are stronger than corresponding ones known for the related class of mathematical programs with complementarity constraints.
Construction of LDPC convolutional codes via difference triangle sets
Authors: Alfarano Gianira N. , Lieb Julia , Rosenthal Joachim
Published: July 2021

In this paper, a construction of $$(n,k,\delta )$$

(
n
,
k
,
δ
)

LDPC convolutional codes over arbitrary finite fields, which generalizes the work of Robinson and Bernstein and the later work of Tong is provided. The sets of integers forming a (k, w)-(weak) difference triangle set are used as supports of some columns of the sliding parity-check matrix of an $$(n,k,\delta )$$

(
n
,
k
,
δ
)

convolutional code, where $$n\in {\mathbb {N}}$$

n
∈
N

, $$n>k$$

n
>
k

. The parameters of the convolutional code are related to the parameters of the underlying difference triangle set. In particular, a relation between the free distance of the code and w is established as well as a relation between the degree of the code and the scope of the difference triangle set. Moreover, we show that some conditions on the weak difference triangle set ensure that the Tanner graph associated to the sliding parity-check matrix of the convolutional code is free from $$2\ell $$

2
ℓ

-cycles not satisfying the full rank condition over any finite field. Finally, we relax these conditions and provide a lower bound on the field size, depending on the parity of $$\ell $$
ℓ
, that is sufficient to still avoid $$2\ell $$

2
ℓ

-cycles. This is important for improving the performance of a code and avoiding the presence of low-weight codewords and absorbing sets.
Measuring affective states from technical debt
Authors: Olsson Jesper , Risfelt Erik , Besker Terese , Martini Antonio , Torkar Richard
Published: July 2021

Context

Software engineering is a human activity. Despite this, human aspects are under-represented in technical debt research, perhaps because they are challenging to evaluate.

Objective

This study’s objective was to investigate the relationship between technical debt and affective states (feelings, emotions, and moods) from software practitioners.

Method

Forty participants (N = 40) from twelve companies took part in a mixed-methods approach, consisting of a repeated-measures (r = 5) experiment (n = 200), a survey, and semi-structured interviews. From the qualitative data, it is clear that technical debt activates a substantial portion of the emotional spectrum and is psychologically taxing. Further, the practitioners’ reactions to technical debt appear to fall in different levels of maturity.

Results

The statistical analysis shows that different design smells (strong indicators of technical debt) negatively or positively impact affective states.

Conclusions

We argue that human aspects in technical debt are important factors to consider, as they may result in, e.g., procrastination, apprehension, and burnout.
Exploration of Enceladus and Titan: investigating ocean worlds’ evolution and habitability in the Saturn system
Authors: Mitri Giuseppe , Barnes Jason , Coustenis Athena , Flamini Enrico , Hayes Alexander , Lorenz Ralph D. , Mastrogiuseppe Marco , Orosei Roberto , Postberg Frank , Reh Kim , Soderblom Jason M. , Sotin Christophe , Tobie Gabriel , Tortora Paolo , Vuitton Veronique , Wurz Peter
Published: July 2021

We present a White Paper with a science theme concept of ocean world evolution and habitability proposed in response to ESA’s Voyage 2050 Call with a focus on Titan and Enceladus in the Saturn system. Ocean worlds in the outer Solar System that possess subsurface liquid water oceans are considered to be prime targets for extra-terrestrial life and offer windows into Solar System evolution and habitability. The Cassini-Huygens mission to the Saturn system (2004–2017) revealed Titan with its organic-rich evolving world with terrestrial features and Enceladus with its active aqueous environment to be ideal candidates to investigate ocean world evolution and habitability. Additionally, this White Paper presents a baseline for a multiple flyby mission with a focused payload as an example of how ocean world evolution and habitability in the Saturn system could be investigated building on the heritage of the Cassini-Huygens mission and complementing the recently selected NASA Dragonfly mission.
Do People Agree on How Positive Emotions Are Expressed? A Survey of Four Emotions and Five Modalities Across 11 Cultures
Authors: Manokara Kunalan , Đurić Mirna , Fischer Agneta , Sauter Disa
Published: July 2021

While much is known about how negative emotions are expressed in different modalities, our understanding of the nonverbal expressions of positive emotions remains limited. In the present research, we draw upon disparate lines of theoretical and empirical work on positive emotions, and systematically examine which channels are thought to be used for expressing four positive emotions: feeling moved, gratitude, interest, and triumph. Employing the intersubjective approach, an established method in cross-cultural psychology, we first explored how the four positive emotions were reported to be expressed in two North American community samples (Studies 1a and 1b: n = 1466). We next confirmed the cross-cultural generalizability of our findings by surveying respondents from ten countries that diverged on cultural values (Study 2: n = 1826). Feeling moved was thought to be signaled with facial expressions, gratitude with the use of words, interest with words, face and voice, and triumph with body posture, vocal cues, facial expressions, and words. These findings provide cross-culturally consistent findings of differential expressions across positive emotions. Notably, positive emotions were thought to be expressed via modalities that go beyond the face.
A Survey of Encoding Techniques for Signal Processing in Spiking Neural Networks
Authors: Auge Daniel , Hille Julian , Mueller Etienne , Knoll Alois
Published: July 2021

Biologically inspired spiking neural networks are increasingly popular in the field of artificial intelligence due to their ability to solve complex problems while being power efficient. They do so by leveraging the timing of discrete spikes as main information carrier. Though, industrial applications are still lacking, partially because the question of how to encode incoming data into discrete spike events cannot be uniformly answered. In this paper, we summarise the signal encoding schemes presented in the literature and propose a uniform nomenclature to prevent the vague usage of ambiguous definitions. Therefore we survey both, the theoretical foundations as well as applications of the encoding schemes. This work provides a foundation in spiking signal encoding and gives an overview over different application-oriented implementations which utilise the schemes.
Dissipative structures in the resonant interaction of laser radiation with nonlinear dispersive medium
Authors: Aleksić Branislav N. , Uvarova Liudmila A. , Aleksić Najdan B.
Published: July 2021

The article presents the results of studies on the stability of dissipative structures (DS) arising in the resonant interaction of laser radiation with a nonlinear medium. Resonant interaction is modeled by the one dimensional complex Ginzburg-Landau equation with a nonconservative cubic–quintic nonlinearity. The areas of existence of stable DS solutions have been determined analytically using a variational approach and confirmed numerically by extensive numerical simulations.
Estimation methods to extract complex permittivity from transmission coefficient in the terahertz band
Authors: Yang Chuang , Wang Jian , Yang Cheng
Published: July 2021

In this paper, the characteristics of the transmission coefficient (S$$_{21}$$

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) measured in free-space at terahertz frequencies are analyzed. The analysis results are used to estimate the permittivity of the material under test, and the estimated permittivity is adopted as an initial-value for the iterative algorithm to extract the complex permittivity of the material from the S$$_{21}$$

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. The iterative extraction technique based on the estimation is efficient, while the iterative extraction technique without the estimation is inefficient. Various known materials in the literature are used to validate the technique in the terahertz band.
A Tracer Study on sCO2 Corrosion with Multiple Oxygen-Bearing Impurities
Authors: Lehmusto Juho , Ievlev Anton V. , Cakmak Ercan , Keiser James R. , Pint Bruce A.
Published: July 2021

Several modern power production systems utilize supercritical CO2 (sCO2), which can contain O2 and H2O as impurities. These impurities may degrade the compatibility of structural alloys through accelerated oxidation. However, it remains unclear which of these impurities plays a bigger role in high-temperature reactions taking place in sCO2. In this study, various model and commercial Fe‐ and Ni‐based alloys were exposed in 300 bar sCO2 at 750 °C to low levels (50 ppm) of O2 and H2O for 1,000 h. 18O-enriched water was used to enable the identification of the oxygen source in the post-exposure characterization of the samples. However, oxygen from the water did not accumulate in the scale, which consisted of Cr2O3 in the cases where a protective oxide formed. A 2wt.% Ti addition to a Ni-22%Cr model alloy resulted in the formation of thicker oxides in sCO2, while a 1wt.% Al addition reduced the scale thickness. A synergistic effect of both Al and Ti additions resulted in an even thicker oxide than what was formed solely by Ti, similar to observations for Ni-based alloy 282.
A generic form of fibre bundle models for root reinforcement of soil
Authors: Meijer G. J.
Published: July 2021

Purpose

The mechanical contribution of plant roots to the soil shear strength is commonly modelled using fibre bundle models (FBM), accounting for sequential breakage of roots. This study provides a generic framework, able to includes the many different existing approaches, to quantify the effect of various model assumptions.

Methods

The framework uses (1) a single model parameter determining how load is shared between all roots, (2) a continuous power-law distribution of root area ratio over a range of root diameters, and (3) power-law relationships between root diameters and biomechanical properties. A new load sharing parameter, closely resembling how roots mobilise strength under landslide conditions, is proposed. Exact analytical solutions were found for the peak root reinforcement, thus eliminating the current need for iterative algorithms. Model assumptions and results were validated against existing biomechanical and root reinforcement data.

Results

Root reinforcements proved very sensitive to the user-defined load sharing parameter. It is shown that the current method of discretising all roots in discrete diameter classes prior to reinforcement calculations leads to significant overestimations of reinforcement. Addition of a probabilistic distribution of root failure by means of Weibull survival functions, thus adding a second source of sequential mobilisation, further reduced predicted reinforcements, but only when the reduction due to load sharing was limited.

Conclusion

The presented solutions greatly simplify root reinforcement calculations while maintaining analytical exactness as well as clarity in the assumptions made. The proposed standardisation of fibre bundle-type models will greatly aid comparison and exchange of data.
Local causation
Authors: Brunet T. D. P.
Published: July 2021

The counterfactual and regularity theories are universal accounts of causation. I argue that these should be generalized to produce local accounts of causation. A hallmark of universal accounts of causation is the assumption that apparent variation in causation between locations must be explained by differences in background causal conditions, by features of the causal-nexus or causing-complex. The local account of causation presented here rejects this assumption, allowing for genuine variation in causation to be explained by differences in location. I argue that local accounts of causation are plausible, and have pragmatic, empirical and theoretical advantages over universal accounts. I then report on the use of presheaves as models of local causation. The use of presheaves as models of local variation has precedents in algebraic geometry, category theory and physics; they are here used as models of local causal variation. The paper presents this idea as stemming from an approach using presheaves as models of local truth. Finally, I argue that a proper balance between universal and local causation can be assuaged by moving from presheaves to fully-fledged sheaf models.
Adhesive Wear Regimes on Rough Surfaces and Interaction of Micro-contacts
Authors: Pham-Ba Son , Molinari Jean-François
Published: July 2021

We develop an analytical model of adhesive wear between two unlubricated rough surfaces, forming micro-contacts under normal load. The model is based on an energy balance and a crack initiation criteria. We apply the model to the problem of self-affine rough surfaces under normal load, which we solve using the boundary element method. We discuss how self-affinity of the surface roughness, and the complex morphology of the micro-contacts that emerge for a given contact pressure, challenge the definition of contact junctions. Indeed, in the context of adhesive wear, we show that elastic interactions between nearby micro-contacts can lead to wear particles whose volumes enclose the convex hull of these micro-contacts. We thereby obtain a wear map describing the instantaneous produced wear volume as a function of material properties, roughness parameters and loading conditions. Three distinct wear regimes can be identified in the wear map. In particular, the model predicts the emergence of a severe wear regime above a critical contact pressure, when interactions between micro-contacts are favored.
Efficacy and safety of onabotulinumtoxinA in patients with overactive bladder: subgroup analyses by sex and by serum prostate-specific antigen levels in men from a randomized controlled trial
Authors: Yokoyama Osamu , Honda Masashi , Yamanishi Tomonori , Sekiguchi Yuki , Fujii Kenji , Kinoshita Kyoko , Nakayama Takashi , Ueno Akikazu , Mogi Takao
Published: July 2021

Purpose

We aimed to assess onabotulinumtoxinA treatment outcomes by sex in patients with overactive bladder (OAB) and then explore the impact of serum prostate-specific antigen (PSA) levels in men.

Methods

Patients inadequately managed with OAB medications were randomized to receive single-dose onabotulinumtoxinA (100 U) or placebo intravesical injection in a phase III trial in Japan. We performed subgroup analyses by sex and post-hoc subgroup analyses using male PSA categories.

Results

In women (n = 186), onabotulinumtoxinA demonstrated statistically significant and clinically relevant improvements in all urinary symptoms at Week 12. In men with lower PSA (< 1.5 ng/mL, n = 40), onabotulinumtoxinA also showed numerically greater reductions in urinary symptom frequency than placebo; the between-group differences (onabotulinumtoxinA minus placebo) in change from baseline in the average daily number at Week 12 for urinary incontinence (UI), urgency UI, micturition, urgency, and nocturia were − 1.43, − 1.79, − 2.81, − 2.45, and − 0.32 episodes, respectively. In men with higher PSA (≥ 1.5 ng/mL, n = 22), onabotulinumtoxinA did not reduce urinary symptom frequency. Some patients treated with onabotulinumtoxinA showed elevated post-void residual urine volume at Week 2 (≥ 200 mL): 4 of 91 women, none of the men with lower PSA and 3 of 11 men with higher PSA.

Conclusions

OnabotulinumtoxinA was efficacious and well tolerated in women and in men with lower PSA levels. Given our post-hoc subgroup analyses which suggested that onabotulinumtoxinA treatment is a good treatment option for OAB males with lower PSA levels, future studies having prostate volume data with larger sample size are warranted to verify our findings.

ClinicalTrials.gov Identifier

NCT02820844 (first posted July 1, 2016). https://clinicaltrials.gov/ct2/show/NCT02820844.