bluuebunny/crossref_metadata_2025 huggingface dataset:
Single dose of tranexamic acid effectively reduces blood loss and transfusion rates in elderly patients undergoing surgery for hip fracture: a randomized controlled trial
Authors: Nikolaou Vasileios S. , Masouros Panagiotis , Floros Themistoklis , Chronopoulos Efstathios , Skertsou Maria , Babis George C.
Published: February 2021

Aims

The aim of this study was to investigate the hypothesis that a single dose of tranexamic acid (TXA) would reduce blood loss and transfusion rates in elderly patients undergoing surgery for a subcapital or intertrochanteric (IT) fracture of the hip.

Methods

In this single-centre, randomized controlled trial, elderly patients undergoing surgery for a hip fracture, either hemiarthroplasty for a subcapital fracture or intramedullary nailing for an IT fracture, were screened for inclusion. Patients were randomly allocated to a study group using a sealed envelope. The TXA group consisted of 77 patients, (35 with a subcapital fracture and 42 with an IT fracture), and the control group consisted of 88 patients (29 with a subcapital fracture and 59 with an IT fracture). One dose of 15 mg/kg of intravenous (IV) TXA diluted in 100 ml normal saline (NS,) or one dose of IV placebo 100 ml NS were administered before the incision was made. The haemoglobin (Hb) concentration was measured before surgery and daily until the fourth postoperative day. The primary outcomes were the total blood loss and the rate of transfusion from the time of surgery to the fourth postoperative day.

Results

Homogeneity with respect to baseline characteristics was ensured between groups. The mean total blood loss was significantly lower in patients who received TXA (902.4 ml (-279.9 to 2,156.9) vs 1,226.3 ml (-269.7 to 3,429.7); p = 0.003), while the likelihood of requiring a transfusion of at least one unit of red blood cells was reduced by 22%. Subgroup analysis showed that these differences were larger in patients who had an IT fracture compared with those who had a subcapital fracture.

Conclusion

Elderly patients who undergo intramedullary nailing for an IT fracture can benefit from a single dose of 15 mg/kg TXA before the onset of surgery. A similar tendency was identified in patients undergoing hemiarthroplasty for a subcapital fracture but not to a statistically significant level. Cite this article: Bone Joint J 2021;103-B(3):442–448.
Complications, mobility, and quality of life in ankle sarcoma patients
Authors: Smolle Maria Anna , Leithner Andreas , Kapper Martin , Demmer Gregor , Trost Carmen , Bergovec Marko , Windhager Reinhard , Hobusch Gerhard Martin
Published: February 2021

Aims

The aims of the study were to analyze differences in surgical and oncological outcomes, as well as quality of life (QoL) and function in patients with ankle sarcomas undergoing three forms of surgical treatment, minor or major limb salvage surgery (LSS), or amputation.

Methods

A total of 69 patients with ankle sarcomas, treated between 1981 and 2017 at two tumour centres, were retrospectively reviewed (mean age at surgery: 46.3 years (SD 22.0); 31 females (45%)). Among these 69 patients 25 were analyzed prospectively (mean age at latest follow-up: 61.2 years (SD 20.7); 11 females (44%)), and assessed for mobility using the Prosthetic Limb Users Survey of Mobility (PLUS-M; for amputees only), the Toronto Extremity Salvage Score (TESS), and the University of California, Los Angeles (UCLA) Activity Score. Individual QoL was evaluated in these 25 patients using the five-level EuroQol five-dimension (EQ-5D-5L) and Fragebogen zur Lebenszufriedenheit/Questions on Life Satisfaction (FLZ).

Results

Of the total number of patients in the study, 22 (32%) underwent minor LSS and 22 (32%) underwent major LSS; 25 underwent primary amputation (36%). Complications developed in 26 (38%) patients, and were more common in those with major or minor LSS in comparison to amputation (59% vs 36% vs 20%; p = 0.022). A time-dependent trend towards higher complication risk following any LSS was present (relative risk: 0.204; 95% confidence interval (CI) 0.026 to 1.614; p = 0.095). In the prospective cohort, mean TESS was higher following minor LSS in comparison to amputation (91.0 vs 67.3; p = 0.006), while there was no statistically significant difference between major LSS and amputation (81.6 vs 67.3; p = 0.099). There was no difference in mean UCLA (p = 0.334) between the three groups (p = 0.334). None of the items in FLZ or EQ-5D-5L were different between the three groups (all p > 0.05), except for FLZ item “self-relation”, being lower in amputees.

Conclusion

Complications are common following LSS for ankle sarcomas. QoL is comparable between patients with LSS or amputation, despite better mobility scores for patients following minor LSS. We conclude that these results allow a decision for amputation to be made more easily in patients particularly where the principles of oncological surgery would otherwise be at risk. Cite this article: Bone Joint J 2021;103-B(3):553–561.
Simple-structure low-loss multi-core fiber LC connector using an align-by-contact method
Authors: Morishima Tetsu , Manabe Ken , Toyokawa Shuhei , Nakanishi Tetsuya , Sano Tomomi , Hayashi Tetsuya
Published: February 2021

We present a novel single-MCF connector without any additional or high-precision parts not found on a standard single-SMF connector. The proposed connector realizes rotational fiber alignment and ferrule floating simultaneously by employing a standard MU ferrule with a straight flange edge and a modified LC housing with a tapered hole that can make contact with the ferrule flange. Fabricated connectors achieved an average loss of 0.07 dB in a random connection test and passed the Telcordia GR-326-CORE mechanical and environmental reliability test. Furthermore, we conducted numerical simulations and confirmed these positive results were due to suppression of ferrule rotation from external forces.
Exploration of exciton dynamics in GaTe nanoflakes via temperature- and power-dependent time-resolved photoluminescence spectra
Authors: Yan Hongyan , Liang Xilong , Dong Shuai , Lei Yu , Zhang Guofeng , Chen Ruiyun , Hu Jianyong , Jing Mingyong , Wang Shen , Su Xingliang , Qin Chengbing , Xiao Liantuan , Jia Suotang
Published: February 2021

GaTe nanoflakes have been receiving much research attention recently due to their applications in optoelectronic devices, such as anisotropic non-volatile memory, solar cells, and high-sensitivity photodetectors from the ultraviolet to the visible region. Further applications, however, have been impeded due to the limited understanding of their exciton dynamics. In this work we perform temperature- and power-dependent time-resolved photoluminescence (PL) spectra to comprehensively investigate the exciton dynamics of GaTe nanoflakes. Temperature-dependent PL measurements manifest that spectral profiles of GaTe nanoflakes change dramatically from cryogenic to room temperature, where the bound exciton and donor-to-acceptor pair transition normally disappear above 100 K, while the charged exciton survives to room temperature. The lifetimes of these excitons and their evolution vs temperature have been uncovered by time-resolved PL spectra. Further measurements reveal the entirely different power-dependent exciton behaviors of GaTe nanoflakes between room and cryogenic temperatures. The underlying mechanisms have been proposed to explore the sophisticated exciton dynamics within GaTe nanoflakes. Our results offer a more thorough understanding of the exciton dynamics of GaTe nanoflakes, enabling further progress in engineering GaTe-based applications, such as photodetectors, light-emitting diodes, and nanoelectronics.
Surface-enhanced Raman scattering by the composite structure of Ag NP-multilayer Au films separated by Al2O3
Authors: Zha Zhipeng , Liu Runcheng , Yang Wen , Li Can , Gao Jinjuan , Shafi Muhammad , Fan Xiuwei , Li Zhen , Du Xuejian , Jiang Shouzhen
Published: February 2021

In the present study, a nanoparticle-multilayer metal film substrate was presented with silver nanoparticles (Ag NPs) assembled on a multilayer gold (Au) film by employing alumina (Al2O3) as a spacer. The SERS performance of the proposed structures was determined. It was suggested that the SERS effect was improved with the increase in the number of layers, which was saturated at four layers. The SERS performance of the structures resulted from the mutual coupling of multiple plasmon modes [localized surface plasmons (LSPs), surface plasmon polaritons (SPPs), as well as bulk plasmon polaritons (BPPs)] generated by the Ag NP-multilayer Au film structure. Furthermore, the electric field distribution of the hybrid system was studied with COMSOL Multiphysics software, which changed in almost consistency with the experimentally achieved results. For this substrate, the limit of detection (LOD) was down to 10−13 M for the rhodamine 6G (R6G), and the proposed SERS substrate was exhibited prominently quantitatively detected capability and high reproducibility. Moreover, a highly sensitive detection was conducted on toluidine blue (TB) molecules. As revealed from the present study, the Ag NP-multilayer Au film structure can act as a dependable SERS substrate for its sensitive molecular sensing applications in the medical field.
Mapeamento das classes do cadastro ambiental rural (CAR) De imóveis rurais familiares e não familiares nas chapadas e grotas do alto Jequitinhonha-MG
Authors: Silva Leonardo França da , Maltez Marcos Antonio Pereira da Fonseca , Silva Emilia Pereira Fernandes da , Assis Kamila Cristina de Credo , Begueline Maria Clara Lelles Moreira , Rezende Bruna Nogueira
Published: February 2021

Com o avanço da tecnologia da informação e o advento das geotecnologias, quanto maior o número de informações globais, regionais e locais, maior é a possibilidade de sucesso do planejamento. o presente artigo teve como objetivo sobrepor informações dos imóveis rurais, áreas de vegetação preservada e nascentes em áreas da agricultura familiar e não familiar, na região das chapadas e grotas do Alto Jequitinhonha, utilizando como banco de dados as informações disponibilizadas pelo SICAR (Sistema Nacional de Cadastro Ambiental Rural), IBGE (Instituto Brasileiro de Geografia e Estatistica e informações topográficas fornecidas pelo SRTM. Para o processamento das informações foi utilizado software de geoprocessamento ArcGis 10.3. A sobreposição das informações se deu a partir das ferramentas do próprio software. Foi possivel que a região do Alto Jequitinhonha é uma região de agricultura familiar tradicional e numerosa, onde o relevo formado por chapadas e grotas determinou os diferentes processos de ocupação e uso dos solos na região. A chegada de grandes empreendimentos, principalmente o reflorestamento com eucalipto, alterou drasticamente a dinâmica da região, a partir dos dados do CAR foi possível observar as mudanças no uso e posse da terra, recursos hídricos e vegetação nativa.
MINERÍA METALÍFERA, GUERRA Y ACUMULACIÓN POR DESPOSESIÓN: EL CASO DEL WOLFRAMIO DURANTE LOS GRANDES CONFLICTOS MILITARES INTERNACIONALES DEL SIGLO XX
Authors: Gómez Lende Sebastián
Published: February 2021

En las últimas décadas, las ciencias sociales han debatido exhaustivamente acerca de las severas consecuencias del avance de la minería metalífera en Argentina. Sin embargo, poco se sabe de los impactos generados por el sector durante las grandes guerras internacionales del Siglo XX, cuando nuestro país se convirtió en exportador de minerales críticos y estratégicos para la industria militar de los países en conflicto. Sobre la base de bibliografía especializada, estadísticas oficiales y reportes periodísticos, este artículo reconstruyó el desarrollo histórico de la minería del tungsteno durante la Primera y la Segunda Guerra Mundial y la Guerra de Corea para determinar si los ciclos de crecimiento resultantes de tales circunstancias implicaron para nuestro país mecanismos de acumulación por desposesión semejantes a los que actualmente prevalecen en el sector minero argentino. Los resultados muestran claramente que este modelo se basó en la privatización y apropiación imperial de recursos naturales, el fraude y la ilegalidad, las redistribuciones estatales y la tercerización de la fuerza de trabajo.
MORFOGÊNESE DE UMA PAISAGEM DE CHAPADAS: O CASO DO EXTREMO SUL DA UNIDADE DO RELEVO CHAPADAS DO RIO SÃO FRANCISCO, MINAS GERAIS
Authors: Pereira Martins Fernanda , Rodrigues Salgado André Augusto
Published: February 2021

As Chapadas do Rio São Francisco correspondem à maior unidade de relevo classificada como do tipo chapada no Brasil. Entretanto, esta região, assim como este tipo de relevo, teve sua morfogênese pouco investigada. O presente trabalho analisou os processos que influenciaram na morfogênese do extremo sul da unidade de relevo brasileiro das Chapadas do Rio São Francisco através da correlação entre: (i) a litologia e morfoestrutura; (ii) sistema de drenagem regional; (iii) parâmetros morfométricos e; (iv) trabalhos de campo. Os resultados apontam para o fato de que a disposição da rede de drenagem é compatível com os lineamentos estruturais, principalmente nos canais de menor ordem que são os responsáveis pela segmentação inicial do amplo planalto em chapadas. Assim, as mudanças no nível de base fizeram os canais se encaixarem e, atualmente, os processos continuam mediante alargamento dos vales dos rios, individualizando os platôs em chapadas.
À qui faire avaler la pilule ?
Authors: Fonquerne Leslie
Published: February 2021

En France, le taux de prévalence contraceptive reste élevé depuis la diffusion des différentes méthodes médicalisées dès les années 1970, dont la pilule représente l’essor. Mais fin 2012, les pilules de troisième et quatrième générations font l’objet d’un scandale médiatique, sanitaire et politique dû à un sur-risque sanitaire qui leur est associé, engendrant une désaffection de la contraception orale dans son ensemble. Malgré une baisse significative de son taux d’usage, la pilule reste cependant la méthode la plus utilisée. Pour autant, cela ne signifie pas que toutes les usagères bénéficient d’un choix contraceptif libre et éclairé. Centré sur les pratiques des professionnel·le·s de santé, cet article propose de rendre compte de l’impact de différentes approches de soin en matière d’inégalités d’accès à l’information et à la prescription de contraception et d’en saisir les spécificités selon les catégorisations de patientes qu’opèrent les praticien·ne·s.
Translanguaging in writing: a bilingual PhD student’s reflection
Authors: Dong Rongrong
Published: February 2021

With a critical narrative approach, this reflective practice research aims to do a personal narrative inquiry on the researcher herself during her dissertation research/writing period. The researcher explores and reflects on her various translanguaging strategies used throughout the course of her dissertation research and writing. Data collection includes her reflective journal entries, interview recordings and transcriptions with her research participants, reflective conversation audio recordings with her peers and research voice memos during her dissertation writing process. Using narrative analysis, this study indicates translanguaging allows the researcher to establish her dual-identities in both U.S. and Chinese educational settings, and helps her to develop her own writer’s voice and also engages her to think more creatively and critically as a researcher and a writer. This study presents a first-person reflective practice that deconstructs bilingual PhD students’ dissertation writing journey. It highlights the significance of bilingual international graduate students’ language repertoire to their academic writing, which matters not only to individual students, but may better serve international student community cross the world.
Von der Kaminkarriere zur boundaryless und protean career? Zum Verhältnis von organisationaler und individueller Karrieresteuerung am Beispiel von Auslandseinsätzen / From organization career to boundaryless and protean career? Analysis of relations between organizational and individual career management in assignments abroad
Authors: Mense-Petermann Ursula
Published: February 2021

Michael Arthur und Douglas Hall haben mit ihren Thesen zur boundaryless und zur protean career eine Debatte über einen Wandel des für westliche Industriegesellschaften typischen Karrieremusters postuliert, und zwar eine Umstellung von der Organisation und des in ihr und von ihr institutionalisierten Karrieremusters der sogenannten ,Kaminkarriere’ auf den einzelnen Erwerbstätigen und seine individuellen Strukturierungs- und Selbst-Managementleistungen. Der hier vorliegende Beitrag vertritt die These, dass hier die Rolle der Organisation für Karrieren zu stark heruntergespielt und zu wenig nach dem Verhältnis von organisationalem und individuellem Karrieremanagement gefragt wird. Der Beitrag macht deshalb einen differenzierenden Vorschlag zur Analyse eines Formwandels von Karriere.
Differentialgeometrische Beschreibung und Analyse Tor-basierter Hamilton'scher Systeme
Authors: Schöberl Markus
Published: February 2021

In diesem Beitrag wird gezeigt, wie man ausgehend von geometrischen Strukturen, welche
man Tor-basierten Hamilton'schen Systemen im finit-dimensionalen Szenario zugrundelegen kann, durch deren Verallgemeinerung
unterschiedliche Tor-basierte Hamilton'sche Darstellungen im Rahmen partieller Differentialgleichungen gewinnt.
Diese unterschiedlichen Systemdarstellungen werden anhand eines mechanischen Beispiels, dem Timoshenko Balken, gegenübergestellt und diskutiert.
Hauptaugenmerk liegt auf der Analyse von strukturellen Eigenschaften der Differentialgleichungen, welche
dann aus regelungstechnischer Sicht von Bedeutung sind.
Flachheitsbasierte Bewegungsplanung für gekoppelte elastische Balken
Authors: Kater Andreas , Meurer Thomas
Published: February 2021

Dieser Beitrag stellt eine systematische Entwurfsmethodik zur flachheitsbasierten Vorsteuerung und Trajektorienplanung für gekoppelte
elastische Balkenstrukturen mit piezoelektrischen Aktoren vor. Auf Basis des mathematischen Modells wird unter Ausnutzung der
spektralen Eigenschaften ein analytischer Zugang zur Konstruktion eines flachen Ausgangs dargestellt. Dies führt auf eine
differenzielle Parametrierung sämtlicher Systemvariablen. Der Nachweis der Konvergenz macht von Eigenschaften ganzer Funktionen in
Kombination mit asymptotischen Eigenwertverteilungen Gebrauch und führt auf ein Problem der Trajektorienplanung für den flachen
Ausgang. Dieser Entwurfsansatz dient als methodische Basis für die Entwicklung eines effizienten semi-analytischen Verfahrens, das
insbesondere die Einbindung geeigneter Approximationen des verteilt-parametrischen Systems ermöglicht. Beide Ansätze werden anhand der
betrachteten Balkenstruktur analysiert und im Rahmen von Simulationen und Experimenten an einem Versuchsaufbau evaluiert.
Befähigung im Wandel
Authors: Bonte Achim
Published: February 2021

Qualifikation, Motivation und Beteiligungschancen des Personals sind der Schlüssel für den notwendigen, gründlichen Umbau der Bibliotheken im digitalen Zeitalter. Der Beitrag skizziert die besonderen Rahmenbedingungen von Personalarbeit im Öffentlichen Dienst und den aktuellen Entwicklungsstand im Bibliothekswesen, um danach die konkreten Herausforderungen für Personalgewinnung und -entwicklung näher zu betrachten. Abschließend werden beispielhaft einige Bausteine für gelungene Personalarbeit in deutschen Bibliotheken vorgestellt.1
Investigating Social Presence in Audio and Text Online Interaction for Language Learning
Authors: Wu Ligao
Published: February 2021

This study aimed at comparing the level of social presence generated in a voice-based chat room and a text-based forum when learners tried to build personal relationships and form an online community for learning on an online language course in China. A mixed-method approach was taken for the study, drawing on data from questionnaires to find out about student perception of social presence, and postings of text messages and audio messages in the communication of the student learning process to search for students’ projected social presence in terms of affective, interactive and cohesive features. Interviews were also conducted to supplement additional information with the hope of forming a complete picture of social presence in the reality of an online learning environment. The text-based forum and the voice-based chat room were found to have a different impact on student social presence. In terms of student perception, most of them were more likely to get to know peers in the text-based forum and thus developed a sense of community in their learning process of the online course. Yet they believed that the voice-based chat room had the advantage of helping them with course learning. In the actual interaction, the voice-based chat room was more interactive although the text-based forum was more affective and cohesive. But in terms of the affective category, the problem with the existing framework in literature was that there were no prosodic features included. Therefore, in future more research is needed to probe for the relationship between prosodic sound features and social presence, and the present theoretic framework must be extended. In interviews, students explained that in the voice-based chat room prosodic features led to higher peer awareness, which further reinforced this need.
A Study of Localization of Task-Based Language Teaching in China
Authors: Liu Chunyan , Guo Rui
Published: February 2021

In view of a series of challenges since Task-Based Language Teaching (TBLT) was introduced into China, we interviewed 14 front-line teachers in primary and secondary schools about their viewpoints and classroom strategies of TBLT. The results show teachers’ willingness to use TBLT. They adopt flexible teaching procedures, apply TBLT creatively, and explore task-based language assessment. The authors argue for inclusive non-doctrinaire approaches to TBLT, and propose to construct localized TBLT theory and practice with Chinese characteristics.
Universal central extensions of gauge algebras and groups
Authors: Janssens Bas , Wockel Christoph
Published: February 2021

We show that the canonical central extension of the group of sections
of a Lie group bundle over a compact manifold, constructed by Neeb and Wockel (2009), is universal.
In doing so, we prove universality of the corresponding central
extension of Lie algebras in a slightly more general setting.
Descente galoisienne sur le groupe de Brauer
Authors: Colliot-Thélène Jean-Louis , Skorobogatov Alexei N.
Published: February 2021

Soit X une variété projective et lisse sur un corps k de
caractéristique zéro.
Le groupe de Brauer de X s'envoie dans les invariants,
sous le groupe de Galois absolu de k, du groupe de Brauer de la même
variété considérée sur une clôture algébrique de k.
Nous montrons que le quotient est fini. Sous des hypothèses supplémentaires,
par exemple sur un corps de nombres, nous donnons des estimations sur
l'ordre de ce quotient. L'accouplement d'intersection entre les groupes de diviseurs et de 1-cycles modulo
équivalence numérique joue ici un rôle important.
For a smooth and projective variety X over a field k
of characteristic zero we prove the finiteness of the
cokernel of the natural map from the Brauer group of X to the
Galois-invariant subgroup of the Brauer group of the same
variety over an algebraic closure of k. Under further conditions,
e.g., over a number field, we give estimates for
the order of this cokernel. We
emphasise the rôle played by the exponent of the discriminant
groups of the intersection pairing between the groups of divisors
and curves modulo numerical equivalence.
Stokes factors and multilogarithms
Authors: Bridgeland Tom , Toledano Laredo Valerio
Published: February 2021

Let G be a complex, affine algebraic group and
a meromorphic connection on the trivial G-bundle over
, with a pole of order 2 at zero and a pole of order
1 at infinity. We show that the map taking the residue
of at zero to the corresponding Stokes factors is
given by an explicit, universal Lie series whose coefficients
are multilogarithms. Using a non-commutative analogue
of the compositional inversion of formal power series, we
show that the same holds for the inverse of , and that
the corresponding Lie series coincides with the generating
function for counting invariants in abelian categories constructed
by D. Joyce.
The production of less harmful and less toxic sparklers in an experiment for school students
Authors: Scheid Michael , Rusan Magdalena , Klapötke Thomas M. , Schwarzer Stefan
Published: February 2021

In this article, a new and simple way of producing sparklers is presented as a school experiment. These sparklers are more environmentally friendly and less health threatening than sparklers produced with existing preparation methods. The problem of conventional sparklers is the toxicity of barium nitrate, which is used as the oxidizer. The substitution of this oxidizer with strontium nitrate and also the reduction of the weight proportion makes the new mixture less dangerous and less toxic. Various tests for the categorization of high-energetic materials show that the newly developed sparklers are not classified as explosives. Furthermore, the tests demonstrate that the newly developed sparklers are not as dangerous as commercial sparklers. Due to their lower health risk, these new sparklers are well suited for use in school education. In addition, expenditure for this experiment is low and integrating it into the upper secondary level curriculum is easy. Sparklers are an impressive example of redox reactions from everyday life. The experiment is a best-practice application for chemistry education, incorporating current results of chemistry research.
Optimization of a Piezoelectric Bending Actuator for a Tactile Virtual Reality Display
Authors: Hofmann Viktor , Twiefel Jens
Published: February 2021

The excitation of mechanoreceptors in the finger with different frequencies and intensities generates a tactile impression. For the experience of a complete surface many distributed sources are needed in the tactile display. For these local stimulations of the finger several piezoelectric bending actuators will be arranged in an array perpendicular to the skin. The challenge in the system design is to transfer high dynamic shear forces to the skin at required frequencies together with a compact display design. In order to estimate the dynamic behavior of the bending actuators a transfer matrix method model based on the Timoshenko beam theory is derived. Beside the outer geometric values, the layered structure of the actuator is included in the model. In addition the influence of the load on the actuator’s tip in lateral and in normal direction as well as on the rotational degree of freedom is taken into account. Using the analytical approach, a parametric study is carried out to find an optimized actuator design for the display. For the validation, the modeled beam is compared with experimental data.
Pcf and abelian groups
Authors: Shelah Saharon
Published: February 2021

We deal with some pcf (possible cofinality theory) investigations
mostly motivated by questions in abelian group theory. We concentrate
on applications to test problems but we expect the combinatorics will
have reasonably wide applications. The main test problem is the
“trivial dual conjecture” which says that there is a quite free abelian
group with trivial dual. The “quite free” stands
for “-free” for a suitable cardinal , the first open case is
. We almost always answer it positively, that is, prove
the existence of -free abelian groups
with trivial dual, i.e., with no non-trivial homomorphisms to the integers. Combinatorially, we prove that “almost
always” there are which are
quite free and have a relevant black box. The qualification “almost always”
means except when we have strong restrictions on cardinal
arithmetic, in fact restrictions which hold “everywhere”. The nicest combinatorial result is probably the so-called
“Black Box Trichotomy Theorem” proved in ZFC. Also we may replace abelian groups by R-modules. Part of our
motivation (in dealing with modules) is that in some sense the improvement
over earlier results becomes clearer in this context.
On the Uniqueness Theorems for the External Problems of the Couple-Stress Theory of Elasticity
Authors: Buchukuri T. , Gegelia T.
Published: February 2021

A formula is obtained for the asymptotic representation of solutions of the basic equations of the couple-stress theory of elasticity. The formula is used in proving the uniqueness theorems of the external boundary value problems.
On the Cardinality of A Semi-Algebraic Set
Authors: Khimshiashvili G.
Published: February 2021

It is shown that the cardinality of a finite semi-algebraic subset over a real closed field can be computed in terms of signatures of effectively constructed quadratic forms.
On the Durrmeyer-Type Modification of Some Discrete Approximation Operators
Authors: Pych-Taberska Paulina
Published: February 2021

In [Kratz and Stadtmüller, J. Approximation Theory 54: 326-337, 1988], for continuous functions f from the domain of certain discrete operators Ln
the inequalities are proved concerning the modulus of continuity of Lnf. Here we present analogues of the results obtained for the Durrmeyer-type modification of Ln
. Moreover, we give the estimates of the rate of convergence of in Hölder-type norms
Fractional Type Operators in Weighted Generalized Hölder Spaces
Authors: Samko S. G. , Mussalaeva Z. U.
Published: February 2021

Weighted Zygmund type estimates are obtained for the continuity modulus of some convolution type integrals. In the case of fractional integrals this is strengthened to a result on isomorphism between certain weighted generalized Hölder type spaces.
Sequential Convergence in Topological Vector Spaces
Authors: Katsaras A. K. , Benekas V.
Published: February 2021

For a given linear topology τ, on a vector space E, the finest linear topology having the same τ convergent sequences, and the finest linear topology on E having the same τ precompact sets, are investigated. Also, the sequentially bornological spaces and the sequentially barreled spaces are introduced and some of their properties are studied.
Two-Dimension-Like Functions Defined on the Class of all Tychonoff Spaces
Authors: Tsereteli I.
Published: February 2021

Two-dimension-like functions are constructed on the class of all Tychonoff spaces. Several of their properties, analogous to those of the classical dimension functions, are established.
On the Convergence and Summability of Series with Respect to Block-Orthonormal Systems
Authors: Nadibaidze G.
Published: February 2021

Statements connected with the so-called block-orthonormalized systems are given. The convergence and summability almost everywhere by the (c, 1) method with respect to such systems are considered. In particular, the well-known theorems of Menshov-Rademacher and Kacmarz on the convergence and (c,1)-summability almost everywhere of orthogonal series are generalized.
Test for Disconjugacy of a Differential Inclusion of Neutral Type
Authors: Haščák A.
Published: February 2021

Generalizations of the disconjugacy for a differential inclusion of neutral type are given. The relation between these generalizations and the existence of solutions of multipoint boundary value problems is discussed and the tests for disconjugacy are established. These tests are applicable to the linear differential equations of neutral type, too.
Imbeddings Between Weighted Orlicz–Lorentz Spaces
Authors: Krbec M. , Lang J.
Published: February 2021

We establish necessary and sufficient conditions for imbeddings of weighted Orlicz–Lorentz spaces.
Obstructions to the Section Problem in a Fibration with a Weak Formal Base
Authors: Saneblidze S.
Published: February 2021

For a class of Serre fibrations with a weak formal base X (or with a degenerated A
∞-algebra structure on the integral cohomology H*(X)), obstructions are defined by means of spherical twisting cochains of ξ. In particular, for a given section sn
: Xn
→ E on n-skeleton of X, the problem of avoiding the (n+1)th obstruction o(sn
) ∈ H

n+1(X; π
n
(F)) to the existence of a section on X

n+1 reduces to solving a system of linear equations with respect to cohomology elements of the groups Hi
(X; π
i
(F)), i < n. Homotopy classification theorems for sections as well as for weak formal maps are given, too.
Non-Abelian Cohomology with Coefficients in Crossed Bimodules
Authors: Inassaridze H.
Published: February 2021

When the coefficients are crossed bimodules, Guin's non-abelian cohomology [Guin, C. R. Acad. Sci. Paris 301: 337–340, 1985], [Guin, J. Pure Appl. Algebra 50: 109–137, 1988] is extended in dimensions 1 and 2, and a nine-term exact cohomology sequence is obtained.
On a Singular Two-Point Boundary Value Problem for the Nonlinear mth-Order Differential Equation with Deviating Arguments
Authors: Půža B.
Published: February 2021

Sufficient conditions of solvability and unique solvability of the boundary value problem

u
(m)(t) = f(t, u(τ
11(t)), . . . , u(τ
1k
(t)), . . . , u
(m–1)(τ

m1(t)), . . .

. . . , u
(m–1)(τ

mk
(t))), u(t) = 0, for t ∉ [a, b],

u
(i–1)(a) = 0 (i = 1, . . . , m – 1), u
(m–1)(b) = 0,

are established, where τ

ij
: [a, b] → R (i = 1, . . . , m; j = 1, . . . , k) are measurable functions and the vector function f : ]a, b[×Rkmn
→ Rn
is measurable in the first and continuous in the last kmn arguments; moreover, this function may have nonintegrable singularities with respect to the first argument.
On Some Multidimensional Versions of A Characteristic Problem for Second-Order Degenerating Hyperbolic Equations
Authors: Kharibegashvili S.
Published: February 2021

Some multidimensional versions of a characteristic problem for second-order degenerating hyperbolic equations are considered. Using the technique of functional spaces with a negative norm, the correctness of these problems in the Sobolev weighted spaces are proved.
The Contact Problem for an Elastic Orthotropic Plate Supported by Periodically Located Bars of Equal Resistance
Authors: Gogolauri L.
Published: February 2021

The contact problem of the plane theory of elasticity is studied for an elastic orthotropic half-plane supported by periodically located (infinitely many) stringers of equal resistance. Using the methods of the theory of a complex variable, the problem is reduced to the Keldysh–Sedov type problem for a circle. The solution of the problem is constructed.
On Three-Dimensional Dynamic Problems of Generalized Thermoelasticity
Authors: Burchuladze T. , Burchuladze D.
Published: February 2021

Lord–Shulman's system of partial differential equations of generalized thermoelasticity [Green and Lindsay, J. Elasticity 2: 1–7, 1972] is considered, in which the finite velocity of heat propagation is taken into account by introducing a relaxation time constant. General aspects of the theory of boundary value and initial-boundary value problems and representation of solutions by series and quadratures are considered using the method of a potential.
The Tensor Category of Linear Maps and Leibniz Algebras
Authors: Loday J. L. , Pirashvili T.
Published: February 2021

We equip the category of linear maps of vector spaces with a tensor product which makes it suitable for various constructions related to Leibniz algebras. In particular, a Leibniz algebra becomes a Lie object in and the universal enveloping algebra functor UL from Leibniz algebras to associative algebras factors through the category of cocommutative Hopf algebras in . This enables us to prove a Milnor–Moore type theorem for Leibniz algebras.
The Dependence of Solution Uniqueness Classes of Boundary Value Problems for General Parabolic Systems on the Geometry of an Unbounded Domain
Authors: Gagnidze A.
Published: February 2021

General boundary value problems are considered for general parabolic (in the Douglas–Nirenberg–Solonnikov sense) systems. The dependence of solution uniqueness classes of these problems on the geometry of a nonbounded domain is established.
On the Number of Representations of Integers by Quadratic Forms in Twelve Variables
Authors: Lomadze G.
Published: February 2021

A way of finding exact explicit formulas for the number of representations of positive integers by quadratic forms in 12 variables with integral coefficients is suggested.
On Bounded Solutions of Systems of Linear Functional Differential Equations
Authors: Hakl R.
Published: February 2021

Sufficient conditions of the existence and uniqueness of bounded on real axis solutions of systems of linear functional differential equations are established.
Non-Noether Symmetries in Singular Dynamical Systems
Authors: Chavchanidze G.
Published: February 2021

The Hojman–Lutzky conservation law establishes a certain correspondence between non-Noether symmetries and conserved quantities. In the present paper the extension of the Hojman–Lutzky theorem to singular dynamical systems is carried out.
On Convergence of Series of Random Elements via Maximal Moment Relations with Applications to Martingale Convergence and to Convergence of Series with p-Orthogonal Summands
Authors: Rosalsky Andrew , Volodin Andrei I.
Published: February 2021

The rate of convergence for an almost surely convergent series of Banach space valued random elements is studied in this paper. As special cases of the main result, known results are obtained for a sequence of independent random elements in a Rademacher type p Banach space, and new results are obtained for a martingale difference sequence of random elements in a martingale type p Banach space and for a p-orthogonal sequence of random elements in a Rademacher type p Banach space. The current work generalizes, simplifies, and unifies some of the recent results of Nam and Rosalsky [Teor. Īmovīr. ta Mat. Statist. 52: 120–131, 1995] and Rosalsky and Rosenblatt [Bull. Inst. Math. Acad. Sinica 11: 185–208, 1983, Nonlinear Anal. 30: 4237–4248, 1997].
Suspension and Loop Objects and Representability of Tracks
Authors: Baues H.-J. , Jibladze M.
Published: February 2021

In the general setting of groupoid enriched categories, notions of suspender and looper of a map are introduced, formalizing a generalization of the classical homotopy-theoretic notions of suspension and loop space. The formalism enables subtle analysis of these constructs. In particular, it is shown that the suspender of a principal coaction splits as a coproduct. This result leads to the notion of theories with suspension and to the cohomological classification of certain groupoid enriched categories.
The Rearrangement Inequality for the Ergodic Maximal Function
Authors: Ephremidze L.
Published: February 2021

The equivalence of the decreasing rearrangement of the ergodic maximal function and the maximal function of the decreasing rearrangement is proved. Exact constants are obtained in the corresponding inequalities.
Geometry of Modulus Spaces
Authors: Khalil R. , Hussein D. , Amin W.
Published: February 2021

Let ϕ be a modulus function, i.e., continuous strictly increasing function on [0, ∞), such that ϕ(0) = 0, ϕ(1) = 1, and ϕ(𝑥+𝑦) ≤ ϕ(𝑥)+ϕ(𝑦) for all 𝑥, 𝑦 in [0, ∞). It is the object of this paper to characterize, for any Banach space 𝑋, extreme points, exposed points, and smooth points of the unit ball of the metric linear space ℓ
ϕ
(𝑋), the space of all sequences (𝑥𝑛), 𝑥𝑛 ∈ 𝑋, 𝑛 = 1, 2, . . . , for which ∑ϕ(‖𝑥𝑛‖) < ∞. Further, extreme, exposed, and smooth points of the unit ball of the space of bounded linear operators on ℓ𝑝, 0 < 𝑝 < 1, are characterized.
Periodic Points and Chaotic-Like Dynamics of Planar Maps Associated to Nonlinear Hill's Equations with Indefinite Weight
Authors: Papini Duccio , Zanolin Fabio
Published: February 2021

We prove some results about the existence of fixed points, periodic points and chaotic-like dynamics for a class of planar maps which satisfy a suitable property of “arc expansion” type. We also outline some applications to the nonlinear Hill's equations with indefinite weight.
Conformal and Quasiconformal Mappings of Close Multiply-Connected Domains
Authors: Samsonia Z. , Zivzivadze L.
Published: February 2021

Doubly-connected and triply-connected domains close to each other in a certain sense are considered. Some questions connected with conformal and quasiconformal mappings of such domains are studied using integral equations.
On A Problem of Linear Conjugation in the Case of Nonsmooth Lines and Some Measurable Coefficients
Authors: Gordadze E.
Published: February 2021

A boundary value problem of linear conjugation is considered for more general curves than those studied previously. A condition on the coefficient is found, under which the classical results are valid for these curves.
Mackey Continuity of Characteristic Functionals
Authors: Kwapień S. , Tarieladze V.
Published: February 2021

Problems of the Mackey-continuity of characteristic functionals and the localization of linear kernels of Radon probability measures in locally convex spaces are investigated. First the class of spaces is described, for which the continuity takes place. Then it is shown that in a non-complete sigmacompact inner product space, as well as in a non-complete sigma-compact metizable nuclear space, there may exist a Radon probability measure having a non-continuous characteristic functional in the Mackey topology and a linear kernel not contained in the initial space. Similar problems for moment forms and higher order kernels are also touched upon. Finally, a new proof of the result due to Chr. Borell is given, which asserts that any Gaussian Radon measure on an arbitrary Hausdorff locally convex space has the Mackey-continuous characteristic functional.
A Factorization Method for an Inverse Neumann Problem for Harmonic Vector Fields
Authors: Kress R.
Published: February 2021

Extending the previous work on the corresponding inverse Dirichlet problem, we present a factorization method for the solution of an inverse Neumann boundary value problem for harmonic vector fields.
On the Roots of Polynomials over Division Algebras
Authors: Topuridze N.
Published: February 2021

The structure of roots is investigated for polynomials in one variable with quaternionic and octonionic coefficients. It is proved that their zero sets consist of a finite number of points and Euclidean spheres of corresponding dimension. The general statements are illustrated by typical examples.
Positive Solutions of a Neutral Difference Equation with Positive and Negative Coefficients
Authors: Tang Xian Hua , Cheng Sui Sun
Published: February 2021

A neutral difference equation with positive and negative coefficients is a natural model for a population with depletion of the aged. In this paper, we obtain conditions which are sufficient for one such equation to support an eventually positive population.
Fuzzy Solutions for Neutral Functional Differential Equations with Nonlocal Conditions
Authors: Arara Amaria , Benchohra Mouffak
Published: February 2021

The Banach fixed point theorem is used to investigate the existence of fuzzy solutions for first and second order neutral functional differential equations with nonlocal conditions.
Relative Inversion and Embeddings
Authors: Dupré Maurice J. , Glazebrook James F.
Published: February 2021

Commencing from a monoidal semigroup 𝐴, we consider the geometry of the space 𝑊(𝐴) of pseudoregular elements. When 𝐴 is a Banachable algebra we show that there exist certain subspaces of 𝑊(𝐴) that can be realized as submanifolds of 𝐴. The space 𝑊(𝐴) contains certain subspaces constituting the Stiefel manifolds of framings for 𝐴. We establish several embedding results for such subspaces, where the relevant maps induce embeddings of associated Grassmann manifolds.
Explicit Solutions of the Basic Boundary Value Problems of Statics of the Elastic Mixture Theory for an Annulus
Authors: Basheleishvili M.
Published: February 2021

Using the complex representation formulae of regular solutions of equations of statics of the theory of elastic mixtures, we construct the explicit solutions of the Dirichlet and Neumann type boundary value problems for an annulus in the form of absolutely and uniformly convergent series.
On the Existence and Uniqueness of a Solution to a Stochastic Differential Equation in a Banach Space
Authors: Mamporia B.
Published: February 2021

Abstarct

A sufficient condition is given for the existence of a solution to a stochastic differential equation in an arbitrary Banach space. The method is based on the concept of covariance operator and a special construction of the Itô stochastic integral in an arbitrary Banach space.
General Existence Principle for Singular BVPs and Its Application
Authors: Rachůnková Irena , Staněk Svatoslav
Published: February 2021

We present a general existence principle which can be used for a large class of singular boundary value problems of the form

where 𝑓 satisfies the local Carathéodory conditions on [0, 𝑇] × 𝐷, a set 𝐷 ⊂ is not closed, 𝑓 has singularities in its phase variables on the boundary ∂𝐷 of 𝐷, and 𝑆 is a closed subset in 𝐶𝑛–1([0, 𝑇]). The proof is based on the regularization and sequential techniques. An application of the general existence principle to singular conjugate (𝑝, 𝑛–𝑝) BVPs is also given.
Investigation of the First and the Second Exterior Plane Boundary Value Problems of Steady State Oscillations in the Linear Theory of Elastic Mixtures
Authors: Svanadze K.
Published: February 2021

Displacement vectors are represented by combinations of special potentials; singular integral equations of the normal type with zero index are obtained for the first and the second boundary value problem of steady oscillations in the theory of elastic mixtures. It is proved that in the case of positive frequencies the corresponding homogeneous singular integral equations have only a trivial solution.
On Homology and Cohomology Groups of Remainders
Authors: Baladze V. , Turmanidze L.
Published: February 2021

Border homology and cohomology groups of pairs of uniform spaces are defined and studied. These groups give an intrinsic characterization of Čech type homology and cohomology groups of the remainder of a uniform space.
Connectedness of a Fine Topology and Localization in Bitopological Spaces
Authors: Dvalishvili B.
Published: February 2021

The paper, consisting of four sections, of which Section 0 is auxiliary, is devoted to some principal questions of the theory of bitoplogical spaces. In Section 1, the 𝑝 -extremally disconnected, (𝑖, 𝑗)-strongly extremally disconnected and (𝑖, 𝑗)-nodec spaces are studied by means of the localization at a point. In Section 2, the (𝑖, 𝑗)-pseudoscattered, (𝑖, 𝑗)-ndscattered, 𝑝 -ultradisconnected and (𝑖, 𝑗)-Moscow spaces are introduced, their interrelations and their relations with the 𝑝 -extremally disconnected spaces are investigated, in particular, when one of the topologies is finer than the other. Section 3 is concerned with the problem of existence of a finer connected topology on a connected topological space and so, it is related to the concept of a maximal connected space.
More on Descent Theory for Schemes
Authors: Mesablishvili B.
Published: February 2021

In this paper we continue the investigation of some aspects of descent theory for schemes that was begun in [Mesablishvili, Appl. Categ. Structures]. Let 𝐒𝐂𝐇 be a category of schemes. We show that quasi-compact pure morphisms of schemes are effective descent morphisms with respect to 𝐒𝐂𝐇-indexed categories given by (i) quasi-coherent modules of finite type, (ii) flat quasi-coherent modules, (iii) flat quasi-coherent modules of finite type, (iv) locally projective quasicoherent modules of finite type. Moreover, we prove that a quasi-compact morphism of schemes is pure precisely when it is a stable regular epimorphism in 𝐒𝐂𝐇. Finally, we present an alternative characterization of pure morphisms of schemes.
On 𝑅-Subweakly Commuting Maps and Invariant Approximations in Banach Spaces
Authors: Shahzad Naseer
Published: February 2021

Abstarct

The paper discusses a new class of noncommuting maps called 𝑅-subweakly commuting maps. The existence of invariant approximations for this class of maps is established. Our results extend, generalize, and improve some known results existing in the literature.