bluuebunny/crossref_metadata_2025 huggingface dataset:
Observing the Inner Shadow of a Black Hole: A Direct View of the Event Horizon
Authors: Chael Andrew , Johnson Michael D. , Lupsasca Alexandru
Published: August 2021

Simulated images of a black hole surrounded by optically thin emission typically display two main features: a central brightness depression and a narrow “photon ring” consisting of strongly lensed images superimposed over the direct emission. The photon ring closely tracks a theoretical curve on the image plane corresponding to light rays that asymptote to bound photon orbits. The size and shape of this critical curve are purely governed by the Kerr geometry; in contrast, the size, shape, and depth of the observed brightness depression depend on the details of the emission region. For instance, images of spherical accretion models display a distinctive dark region—the “black hole shadow”—that completely fills the photon ring. By contrast, in models of equatorial disks extending to the event horizon, the darkest region in the image is restricted to a much smaller area—an inner shadow—whose edge lies near the direct lensed image of the equatorial horizon. Using both general relativistic MHD simulations and semi-analytic models, we demonstrate that the photon ring and inner shadow may be simultaneously visible in submillimeter images of M87*, where magnetically arrested disk simulations predict that the emission arises in a thin region near the equatorial plane. We show that the relative size, shape, and centroid of the photon ring and inner shadow can be used to estimate the black hole mass and spin, breaking degeneracies in measurements of these quantities from the photon ring alone. Both features may be accessible to direct observation via high-dynamic-range images with a next-generation Event Horizon Telescope.
The Bulk Flow Velocity and Acceleration of the Inner Jet in M87
Authors: Punsly Brian
Published: August 2021

A high sensitivity, 7 mm Very Long Baseline Array image of M87 is analyzed in order to estimate the jet velocity within 0.65 mas of the point of origin. The image captured a high signal-to-noise, double-ridged, counter-jet extending ∼1 mas from the nucleus. After defining conditions and requirements that justify approximate time averaged bilateral symmetry, a continuous set of Lorentz transformations are found that map the double-ridged counter-jet intensity profile into the double-ridged jet intensity profile. The mapping is realized by a uniformly accelerating flow with intrinsic velocity of ∼0.27c at 0.4 mas (a de-projected distance of 0.38 lt-yr) to 0.38c at 0.65 mas (a de-projected distance of 0.61 lt-yr) from the nucleus. Since the velocity field is derived from the global surface brightness profile and does not depend on the motion of enhanced features, it is most likely a bulk flow velocity as opposed to a pattern velocity. This interpretation is corroborated by the fact that the distribution of the apparent velocities of previously identified individual features (from the literature) within 0.65 mas of the nucleus are consistent with local hydrodynamic shocks being advected with the local bulk flow velocity. The bulk flow velocity of the visible inner jet is a constraint that can potentially break degeneracies between numerical simulations that are designed to replicate both the annulus that was imaged by the Event Horizon Telescope as well as the base of the inner jet.
Delta neutrophil index: in search of an early indicator of sepsis
Authors: Peneva Pavlina , Nikolova Silviya , Bocheva Yana
Published: August 2021

Introduction: Sepsis is a significant cause of morbidity and mortality worldwide. Current clinical practice, however, lacks reliable diagnostic indicators for it and its prognosis.

Aim: The present study aimed to investigate the efficacy of delta neutrophil index (DNI), which reflects the proportion of circulating immature granulocytes, in predicting infections and sepsis.

Materials and methods: A prospective non-interventional single-center clinical follow-up study was performed in a Bulgarian ICU  between January 1, 2017 and May 31, 2018.  We analyzed adult patients: 45 patients met the sepsis criteria, as defined in SEPSIS-3, whereas 37 were infected patients fulfilling no criteria of sepsis. Logistic regression and Roc-curve analysis were used to evaluate the severity and prognostic value of DNI as a prediction marker in critically ill septic patients.

Results: The results have shown that at DNI values of 1.4 there is 73% sensitivity and 87% specificity (AUC 0.764, 95% CI 0.650–0.878, p=0.0001) to assume the presence of sepsis. Additionally, DNI was significantly associated with the severity of the condition of patients, the organ dysfunction and the IL-8 marker.

Conclusions: DNI may serve as a useful marker for early diagnosis of sepsis and could support decision making process regarding its treatment at an early stage of a disease development.
High-sensitivity CRP levels in women with gestational hypertension, preeclampsia and in normotensive pregnant women and its correlations
Authors: Gencheva Dolina G. , Nikolov Fedya P. , Uchikova Ekaterina H. , Mihaylov Rosen D. , Pencheva Blagovesta G. , Ivanova Katerina I.
Published: August 2021

Introduction: Gestational hypertension is a less investigated hypertensive disorder of pregnancy than preeclampsia, but evidence exists of an unfavourable cardiovascular profile for women after such a pregnancy.

Aim: To determine serum high-sensitivity C-reactive protein (hs-CRP) levels in women with preeclampsia, gestational hypertension, and in normotensive pregnancy in order to assess the cardiovascular implications and to examine its correlations with some characteristics of women.

Materials and methods: Thirty-six women with gestational hypertension, thirty-seven with preeclampsia, and fifty maternal and gestational age-matched controls were included in a single-center prospective clinical-epidemiological study. Serum hs-CRP levels were determined using ELISA method.

Results: Significantly higher hs-CRP levels were found in the gestational hypertension group than in the controls (p=0.043), but not in the preeclampsia group (p=0.445). The levels between the two pathological groups did not differ significantly (p=0.247). Odds ratio for hs-CRP levels higher than the provided cut-off was 3.31 (95% CI 1.32–8.29) for the presence of gestational hypertension. In the normotensive pregnant women, the hs-CRP levels had a positive correlation with BSA, pre-pregnancy and current BMI, but such correlations were absent in the hypertensive groups. There were no correlations with the maternal or gestational age, current weight gain in any of the groups or with the highest detected blood pressure in the pathological groups. These levels did not differ according to gravidity, smoking status and smoking during pregnancy.

Conclusions: Elevation of hs-CRP was more pronounced in women with gestational hypertension than in women with preeclampsia, which could indicate a different pathophysiological mechanism and a higher cardiovascular risk for those women.
Perception and knowledge of grasshoppers among indigenous communities in tropical forest areas of southern Cameroon: Ecosystem conservation, food security, and health
Authors: Ngoute Charly Oumarou , Hunter David , Lecoq Michel
Published: August 2021

The increased attention given to health, food security, and biodiversity conservation in recent years should bring together conventional scientists and indigenous people to share their knowledge systems for better results. This work aims to assess how grasshoppers are perceived by the local people in southern Cameroon, particularly in terms of food, health, and landscape conservation. Villagers were interviewed individually using a rapid rural assessment method in the form of a semi-structured survey. Nearly all people (99%) declared that they are able to identify local grasshoppers, generally through the color of the insect (80%). Crop fields were the most often cited landscape (16%) in terms of abundance of grasshoppers, with forest being less mentioned (8%). In general, villagers claimed that grasshopper abundance increased with forest degradation. Grasshoppers were found during all seasons of the year but noted to be more abundant during the long dry seasons. People found grasshoppers both useful and harmful, the most harmful reported being Zonocerus variegatus, an important crop pest. Cassava is the most attacked crop with 75–100% losses. Industrial crops, such as cocoa, coffee, and bananas, were not cited as being damaged by grasshoppers. The most effective conventional method cited for the control of pest grasshoppers is the use of pesticides (53%) with, in most cases (27%), a 75–100% efficiency. The traditional method of spreading ash was also often cited (19%), with an estimated efficiency of 25–75%. Biological methods were neither cited nor used by the villagers. Most of them (87%) declared that they eat grasshoppers; some sold these insects in the market (58%) and some used them to treat diseases (11%).
A review of the Eviota zebrina complex, with descriptions of four new species (Teleostei, Gobiidae)
Authors: Tornabene Luke , Greenfield David W. , Erdmann Mark V.
Published: August 2021

The Eviota zebrina complex includes eight species of closely-related dwarfgobies, four of which are herein described as new. The complex is named for Eviota zebrina Lachner & Karnella, 1978, an Indian Ocean species with the holotype from the Seychelles Islands and also known from the Maldives, which was once thought to range into the Gulf of Aqaba and the Red Sea eastward to the Great Barrier Reef of Australia. Our analysis supports the recognition of four genetically distinct, geographically non-overlapping, species within what was previously called E. zebrina, with E. zebrina being restricted to the Indian Ocean, E. marerubrumsp. nov. described from the Red Sea, E. longirostrissp. nov. described from western New Guinea, and E. pseudozebrinasp. nov. described from Fiji. The caudal fin of all four of these species is crossed by oblique black bars in preservative, but these black bars are absent from the four other species included in the complex. Two of the other species within the complex, E. tetha and E. gunawanae are morphologically similar to each other in having the AITO cephalic-sensory pore positioned far forward and opening anteriorly. Eviota tetha is known from lagoonal environments in Cenderawasih Bay and Raja Ampat, West Papua, and E. gunawanae is known only from deeper reefs (35–60 m) from Fakfak Regency, West Papua. The final two species are E. cometa which is known from Fiji and Tonga and possesses red bars crossing the caudal fin (but lost in preservative) and a 9/8 dorsal/anal-fin formula, and E. oculineatasp. nov., which is described as new from New Guinea and the Solomon Islands, and possesses an 8/7 dorsal/anal-fin formula and lacks red caudal bars. Eviota oculineata has been confused with E. cometa in the past.
Synorthocladius federicoi sp. nov., a new species occurring in the middle basin of the Adige River, northern Italy (Diptera, Chironomidae, Orthocladiinae)
Authors: Lencioni Valeria , Moubayed Joel
Published: August 2021

An adult male Synorthocladius was collected in the middle basin of the Adige River in the city of Verona, northern Italy. A combination of atypical characters for the genus signalled a new species. Synorthocladius federicoisp. nov. is here diagnosed and described. The new species is known only from its type locality and is presumed to be a local biogeographical representative of the Italian Pre-Alps. An emended generic diagnosis, a key to known Synorthocladius from Europe and comments on the taxonomic position of the new species are given.
Le régime de change contribue-t-il à la diversification des exportations en Afrique ?
Authors: Avom Désiré , Malah Kuété Flora Yselle , Owoundi Ferdinand
Published: August 2021

La question du choix d’un régime de change reste une problématique d’actualité pour les économies contemporaines, tout autant que celle des déterminants de la diversification des exportations des pays en développement. Aussi, cet article se propose-t-il d’examiner la contribution du régime de change au niveau de diversification des exportations des pays africains. A l’aide des classifications de jure et de facto et d’une méthode d’estimation non paramétrique fondée sur l’appariement des scores de propension, nous montrons que le régime de change fixe est associé à des niveaux de diversification inférieurs, comparativement aux régimes intermédiaires ou flexibles. Cet effet s’opère principalement par le canal de la marge extensive, puisque la lenteur de l’ajustement des prix relatifs en régime fixe inhibe les incitations à la production de nouveaux biens. Les résultats sont d’autant plus pertinents que : (i) les pays sont mieux dotés en ressources naturelles ; (ii) la qualité des institutions est plus faible ; (iii) les pays appartiennent à la Zone franc. Ainsi, l’article met en lumière l’importance de la qualité des institutions comme condition nécessaire d’atténuation de l’effet réducteur des incitations à la production de nouveaux biens en régime fixe. Codes JEL : C23, E42, F1, Q32.
Le développement du marché modifie-t-il l’équilibre entre les déterminants économiques et sociaux dans la division du travail au sein du ménage ? Une étude longitudinale de la Chine rurale
Authors: He Yong
Published: August 2021

À l’aide d’un échantillon de panel de plus de 3 000 ménages ruraux chinois interrogés pendant 21 ans, cette étude estime l’évolution des rôles relatifs du statut familial et de l’avantage comparatif en matière de capital humain dans la détermination de la division du travail au sein du ménage, dans le contexte d’un développement rapide du marché. Elle constate que le développement du marché a amélioré le statut des femmes et a modifié la règle traditionnelle « les femmes à l’intérieur et les hommes à l’extérieur ». Le développement du marché a également affecté davantage de jeunes travaillant à des emplois rémunérés à l’extérieur, et a laissé une part plus importante de personnes âgées et d’adolescents dans des activités semi-marchandes et des tâches ménagères à la campagne. Ces résultats montrent une importance croissante du capital humain par rapport au statut familial dans la détermination de l’allocation du temps. Codes JEL: D13, J22, O12.
Mourir en biosécurité ? Une convocation à plus d’humanité
Authors: Trébuchet Marie-Dominique
Published: August 2021

Avec l’épidémie de Covid-19 et le décompte journalier des morts, il semble que la mort réintègre l’espace public. Mais de quelle manière le fait-elle ? Chiffrée et anonyme ou singulière et humaine ? Le mantra de la politique biosécuritaire qu’est la « sécurisation du vivant » parce qu’il réduit l’être humain à sa composante biologique participe à une forme de déshumanisation de la mort et des conditions du mourir. Face aux injonctions biosécuritaires et au risque d’effacement de la mort singulière, d’autres ressources peuvent être convoquées. Elles émergent des récits singuliers qui révèlent à la fois ce phénomène de déshumanisation et le sursaut éthique de sujets singuliers face à l’inacceptable. Un autre paradigme est possible, fondé et au service de l’authentiquement humain.
Penser les dilemmes moraux en Ehpad à la lumière d’une anthropologie théologique du sujet vulnérable
Authors: Kerdraon Anne-Solen
Published: August 2021

Lorsque la pandémie de Covid-19 est apparue en France, les Ehpad ont été tout particulièrement touchés. Si la surmortalité qui y a alors été constatée s’explique par la santé fragile de ses résidents, leur difficulté à appliquer les gestes barrières ou encore par le mode de vie collectif en ces établissements, l’augmentation tout aussi importante des phénomènes de glissement alors observés a mis en évidence le caractère potentiellement délétère de la mesure d’endiguement mise en place pour juguler la propagation du virus. Ce qui visait à protéger les résidents les a en réalité arrachés à ce qui leur donnait le goût de vivre et les a précipités vers la mort. Le dilemme moral ainsi manifesté met en évidence non seulement la vulnérabilité de l’existence humaine, mais aussi la beauté et la grandeur qui lui sont indissolublement associées dès lors que nous nous mettons à l’école du Dieu vulnérable qui se révèle en Jésus-Christ.
Les vaccins. Questions éthiques
Authors: Fino Catherine
Published: August 2021

L’usage d’un vaccin requiert un discernement éthique sur ses conditions de fabrication, ses modalités d’action, la tension entre le respect de la liberté individuelle et la promotion du bien commun. Il s’agit parfois d’évaluer le degré de responsabilité dans la collaboration au mal, ou l’effectivité d’une manipulation du vivant, et de poser un jugement proportionné. Il s’agit toujours de préserver la nécessaire adaptabilité du vivant face au danger, comme un don de la Création qui renforce le devoir d’évaluer les limites qui doivent être assignées à la technique. Il faut enfin promouvoir la justice dans l’accès aux vaccins, en privilégiant les plus vulnérables, et le bien commun qui requiert collaboration et action concrète de la part de chaque citoyen, des institutions y compris l’Église, jusqu’au niveau économique et géopolitique.
Aller aux périphéries par temps de pandémie. Des ressources possibles dans l’esprit de Laudato si’ et Fratelli tutti
Authors: Pian Christian
Published: August 2021

Partant du constat que la pandémie qui nous touche a été un défi pour l’Église comme pour toute la société, le propos de cette contribution est de s’intéresser à un aspect qui a été peu considéré pour lui-même au plan théologique, à savoir celui de l’action de cette Église aux périphéries selon l’expression du pape François. On cherche à montrer qu’un certain nombre de documents ecclésiaux rendus publics depuis le début de la crise, dans l’esprit de Laudato si’ , puis de Fratelli tutti – qui est lui-même un texte produit dans ce temps de pandémie –, constituent des ressources utiles pour une réflexion en la matière. On souligne ensuite le défi qui est posé aux baptisés sur ces bases pour être toujours plus membres d’une Église résistante et en sortie.
La vie et l’œuvre du théologien moraliste Eberhard Schockenhoff (1953-2020)
Authors: Baumann Klaus , Feix Marc
Published: August 2021

L’article retrace la vie et l’œuvre du théologien moraliste Eberhard Schockenhoff, décédé brutalement en 2020. Professeur à l’université de Fribourg-en-Brisgau, ce théologien s’est particulièrement distingué par ses travaux sur l’histoire et les fondements de la théologie morale, ainsi que sur les questions d’éthique de la vie, d’éthique de la paix et plus récemment sur l’éthique sexuelle et l’art d’aimer. Dans son œuvre théologique, sur la base de la tradition de la foi commune, il a été particulièrement attentif au dialogue œcuménique et à penser une éthique de la vertu comme éthique de la liberté fondée sur l’interdisciplinarité entre la philosophie, la théologie et l’anthropologie. Il a conçu le projet d’une tension féconde entre l’ecclésialité, les ressources des sciences humaines et le souci de la contemporanéité.
Générations d’Adam : théologie et race dans la pensée protestante anglaise
Authors: Walsham Alexandra , Trogrlic Élise , Morieux Renaud
Published: August 2021

Cet essai examine le fonctionnement de la race dans l’imaginaire généalogique anglais aux xvi e et xvii e siècles. À travers une étude de la pensée réformée sur le péché originel et le salut, il examine le lien entre la théologie protestante et les conceptions du lignage et fait ressortir les ambivalences et les tensions intrinsèques à ce lien entre c. 1560 et 1660. Il explore les traces linguistiques et conceptuelles de la race dans une série de champs sémantiques et culturels croisés et examine comment les catégories d’identité et de différence, d’appartenance et d’affinité, d’inclusion et d’exclusion, ont été construites dans le contexte d’une Réforme qui a, par inadvertance, ancré la diversité religieuse. Le double problème de savoir si l’iniquité et la foi ont été transmises à travers les générations éclaire comment les protestants réformés ont réconcilié la doctrine de la prédestination avec les idées sur la nature, l’éducation et l’hérédité. Il démontre certaines des façons dont la théologie a simultanément stimulé et inhibé la pensée raciale.
La disparition de Canaan : malédiction de Cham et justifications de l’esclavage à l’époque moderne
Authors: Whitford David M. , Trogrlic Élise
Published: August 2021

Cet article examine certaines des premières constructions modernes de la « malédiction de Cham ». La « malédiction de Cham » est fondée sur l’histoire de la Genèse 9 dans laquelle Cham, l’un des fils de Noé, voit la nudité de son père. En réponse, Noé maudit le fils de Cham, Canaan, pour le réduire en servitude. Bien que Cham ne soit pas maudit et que la race ne soit jamais évoquée dans le texte biblique, la « deuxième malédiction (ou chute) de Cham » est devenue une défense idéologique et théologique de l’esclavage des Africains, puis de la ségrégation aux États-Unis. Comment cela s’est-il produit ? En examinant de près l’exégèse, les sermons et les commentaires du début de l’ère moderne, cet article soutient que l’élimination figurative et rhétorique de Canaan du texte biblique a été une première étape cruciale dans la création du mythe d’un Cham maudit et servile.
L’imaginaire éthiopien dans le premier monde hispanique : esclavage et baptême dans le Catéchisme évangélique de Sandoval
Authors: Ireton Chloe L. , Trogrlic Élise
Published: August 2021

Parmi les nombreuses « vérités » répandues dans la recherche sur la couleur de peau noire dans le monde ibérique du xvi e et du début du xvii e siècle, on retrouve souvent l’idée que la notion de pureté du sang a conduit les penseurs ibériques à exclure d’office les Africains de toute possibilité de revendiquer le statut de Vieux Chrétiens. Cette perspective biaisée a occulté de nombreux discours produits au cours de cette période en lien avec l’Afrique, le catholicisme et la légitimité de l’esclavage des noirs Africains. Or certains théologiens et écrivains de la période ont cherché, pour des raisons extrêmement variées, à dépeindre les Africains comme des anciens chrétiens issus de lignées à la pureté religieuse irréprochable. Le présent article analyse la manière dont Alonso de Sandoval (1576-1652), jésuite du xvii e siècle établi à Carthagène des Indes (dans l’actuelle Colombie), s’est appuyé sur des représentations de l’Éthiopie chrétienne pour construire ce type de récit des origines chrétiennes anciennes des Africains, récit dont il se servit pour justifier l’asservissement de tous les Noirs d’Afrique. Cet article retrace donc les débats pluriels et contradictoires sur l’Afrique, la couleur de peau et la chrétienté aux xvi e - xvii e siècles, en mettant en avant le besoin de réévaluer la coexistence de points de vue très différents sur la justification de l’esclavage, la couleur noire et l’Afrique dans les premiers temps de l’empire castillan.
Well-posed control problems related to second-order differential inclusions
Authors: Affane Doria , Yarou Mustapha Fateh
Published: August 2021

The paper deals with quadratic optimal control problems, we study the equivalence between well-posed problems and affinity on the control for a second-order differential inclusions with two-points conditions, governed by a maximal monotone operator in a finite dimensional space.
Local null controllability of a class of non-Newtonian incompressible viscous fluids
Authors: de Carvalho Pitágoras Pinheiro , Límaco Juan , Menezes Denilson , Thamsten Yuri
Published: August 2021

We investigate the null controllability property of systems that mathematically describe the dynamics of some non-Newtonian incompressible viscous flows. The principal model we study was proposed by O. A. Ladyzhenskaya, although the techniques we develop here apply to other fluids having a shear-dependent viscosity. Taking advantage of the Pontryagin Minimum Principle, we utilize a bootstrapping argument to prove that sufficiently smooth controls to the forced linearized Stokes problem exist, as long as the initial data in turn has enough regularity. From there, we extend the result to the nonlinear problem. As a byproduct, we devise a quasi-Newton algorithm to compute the states and a control, which we prove to converge in an appropriate sense. We finish the work with some numerical experiments.
Stackelberg-Nash null controllability of heat equation with general dynamic boundary conditions
Authors: Boutaayamou Idriss , Maniar Lahcen , Oukdach Omar
Published: August 2021

This paper deals with the hierarchical control of the anisotropic heat equation with dynamic boundary conditions and drift terms. We use the Stackelberg-Nash strategy with one leader and two followers. To each fixed leader, we find a Nash equilibrium corresponding to a bi-objective optimal control problem for the followers. Then, by some new Carleman estimates, we prove a null controllability result.
Telegraph systems on networks and port-Hamiltonians. I. Boundary conditions and well-posedness
Authors: Banasiak Jacek , Błoch Adam
Published: August 2021

The paper is concerned with a system of linear hyperbolic differential equations on a network coupled through general transmission conditions of Kirchhoff's-type at the nodes. We discuss the reduction of such a problem to a system of 1-dimensional hyperbolic problems for the associated Riemann invariants and provide a semigroup-theoretic proof of its well-posedness. A number of examples showing the relation of our results with recent research is also provided.
Stationary distribution and extinction of a stochastic SEIQ epidemic model with a general incidence function and temporary immunity
Authors: Zhang Yuhuai ,   College of Economics and Management, Nanjing University of Aeronautics and Astronautics, Nanjing, Jiangsu 211106, China, Ma Xinsheng , Din Anwarud ,   Department of Mathematics, Zhejiang International Studies University, Hangzhou 310012, China,   Department of Mathematics, Sun Yat-sen University, Guangzhou 510275, China
Published: August 2021

In this paper, we propose a novel stochastic SEIQ model of a disease with the general incidence rate and temporary immunity. We first investigate the existence and uniqueness of a global positive solution for the model by constructing a suitable Lyapunov function. Then, we discuss the extinction of the SEIQ epidemic model. Furthermore, a stationary distribution for the model is obtained and the ergodic holds by using the method of Khasminskii. Finally, the theoretical results are verified by some numerical simulations. The simulation results show that the noise intensity has a strong influence on the epidemic spreading.
Analysis of some Katugampola fractional differential equations with fractional boundary conditions
Authors: Łupińska Barbara ,   Institute of Computer Science, University of Bialystok, Konstantego Ciołkowskiego 1M, 15-245 Białystok, Poland, Schmeidel Ewa
Published: August 2021

In this work, some class of the fractional differential equations under fractional boundary conditions with the Katugampola derivative is considered. By proving the Lyapunov-type inequality, there are deduced the conditions for existence, and non-existence of the solutions to the considered boundary problem. Moreover, we present some examples to demonstrate the effectiveness and applications of the new results.
A model of malaria population dynamics with migrants
Authors: Witbooi Peter ,   Department of Mathematics and Applied Mathematics, University of the Western Cape, Private Bag X17, Bellville 7535, Republic of South Africa, Abiodun Gbenga , Nsuami Mozart
Published: August 2021

We present a compartmental model in ordinary differential equations of malaria disease transmission, accommodating the effect of indoor residual spraying on the vector population. The model allows for influx of infected migrants into the host population and for outflow of recovered migrants. The system is shown to have positive solutions. In the special case of no infected immigrants, we prove global stability of the disease-free equilibrium. Existence of a unique endemic equilibrium point is also established for the case of positive influx of infected migrants. As a case study we consider the combined South African malaria region. Using data covering 31 years, we quantify the effect of malaria infected immigrants on the South African malaria region.
Neural networks for classification of strokes in electrical impedance tomography on a 3D head model
Authors: Candiani Valentina ,   Department of Mathematics and Systems Analysis, Aalto University, P.O. Box 11100, FI-00076 Aalto, Espoo, Finland, Santacesaria Matteo ,   MaLGa Center, Department of Mathematics, University of Genoa, Via Dodecaneso 35, 16146 Genova, Italy
Published: August 2021

We consider the problem of the detection of brain hemorrhages from three-dimensional (3D) electrical impedance tomography (EIT) measurements. This is a condition requiring urgent treatment for which EIT might provide a portable and quick diagnosis. We employ two neural network architectures - a fully connected and a convolutional one - for the classification of hemorrhagic and ischemic strokes. The networks are trained on a dataset with $ 40\, 000 $ samples of synthetic electrode measurements generated with the complete electrode model on realistic heads with a 3-layer structure. We consider changes in head anatomy and layers, electrode position, measurement noise and conductivity values. We then test the networks on several datasets of unseen EIT data, with more complex stroke modeling (different shapes and volumes), higher levels of noise and different amounts of electrode misplacement. On most test datasets we achieve $ \geq 90\% $ average accuracy with fully connected neural networks, while the convolutional ones display an average accuracy $ \geq 80\% $. Despite the use of simple neural network architectures, the results obtained are very promising and motivate the applications of EIT-based classification methods on real phantoms and ultimately on human patients.
Paradox in deviation measure and trap in method improvement—take international comparison as an example
Authors: Qiu Dong ,   School of Statistics, Jiangxi University of Finance and Economics, Nanchang, 330013, China, Li Dongju ,   School of Statistics and Big Data, Henan University of Economics and Law, Zhengzhou, 450046, China
Published: August 2021

Due to the problem of "true value agnostic" in the measurement of the real world, people believe that the existing methods can be closer to the true value by improving them. Therefore, they are willing to excessively affirm the more advanced method and deny the relatively "traditional" method. Taking the exchange rate method and purchasing power parity method commonly used in international economic comparison as examples, this paper generalizes the problems revealed by the exchange-rate-deviation index and concludes that there are at least three paradoxes in the deviation measurement of different methods. These paradoxes are the paradox of behavior significance, the paradox of comparative object, and the paradox of measurement result. The reason is that there is a cautionary trap in the improvement or innovation of measurement methods in reality. Sometimes the improved method is not necessarily better than the unimproved method. People tend to prefer advanced technology and methodology, but the problem of statistical input and related statistical benefits need to be considered in practical measurement. In fact, these basic problems still exist in some of the methods of economic statistics that we regard as common sense. When learning or introducing new methods, scholars do not absolutize the existing methods and conclusions. They should pay attention to critical experience, avoid the trap of improvement methods, and seek real improvement or innovation.
La carte controversée du Pacifique pour la Deuxième expédition du Kamchatka (1733-1743) : blanchir les allégories de la carte ou poursuivre une gloire fuyante
Authors: Gouzévitch Irina
Published: August 2021

Peu de cartes géographiques du xviiie siècle ont suscité autant de polémiques que celle préparée par Joseph Nicolas Delisle en 1731 pour la Deuxième expédition du Kamtchatka. Établie selon les connaissances de l’époque pour fixer les tâches aux explorateurs, la carte s’est avérée inexacte, et ceci a coûté la vie à plusieurs membres de l’expédition, y compris à son chef, Vitus Bering. La responsabilité en a été imputée à Delisle. Dans cette étude, nous allons argumenter une vision alternative fondée sur l’analyse des trois cartes du Pacifique – de 1731/33, 1745 et 1752 – associées au nom de Delisle, en démontrant leur influence variable sur la diffusion des connaissances dans ce domaine. Plus généralement, nous y interrogerons les enjeux divergents qui ont déterminé les attitudes des différents pays et groupes d’intérêt à l’égard de la connaissance scientifique, en mettant un accent sur la notion du « secret d’Etat ».
Revealing maritimity in 19th century France
Authors: Barron Géraldine
Published: August 2021

The term maritimity, defined by geographers in the early 1990s, offers an interesting conceptual framework for analysing the evolution of the relationship with the maritime world during the 19th century. A century of revolutions, this period is marked by deep and lasting changes in the relationship with the sea, especially affecting cultural, social and artistic practices. It was also affected by the emergence of heritage concerns which paved the way for new disciplines such as naval archaeology or nautical ethnography. Representations of the maritime world have been fundamentally changed as a result.
L’invention du « nucléaire japonais » : l’évolution du rapport entre la nation et l’atome au prisme des ambitions techno-politiques de l’archipel
Authors: Inoue Masatoshi
Published: August 2021

Depuis les années 1950, le Japon poursuit activement son développement électronucléaire, bien que ce pays ait directement connu des catastrophes causées par l’atome militaire et civil. Afin d’expliquer cette « obstination » pour l’atome, cet article propose une nouvelle synthèse des trajectoires nucléaires dans l’archipel, en distinguant trois étapes dans l’évolution des ambitions techno-politiques (importations, appropriation/invention, exportation). Ainsi, il se focalise sur la façon dont les promoteurs japonais ont rendu l’énergie nucléaire indispensable pour le « progrès » national. Cette approche nous permet de mettre en lumière les efforts des défenseurs à sans cesse renouveler les formes d’attachement de la nation nipponne à l’atome à travers divers projets technologiques. Dans ce cadre, les expériences des désastres leurs ont servi d’outils pour revendiquer la légitimité « japonaise » à promouvoir l’atome.
La guerre du chalut
Authors: Grancher Romain
Published: August 2021

Cet article part du récit d’une émeute de gens de mer survenue dans le port de Dieppe au mois novembre 1818. Dirigée contre des pêcheurs étrangers à la communauté, cette émeute est envisagée ici comme la trace d’un conflit d’usage de longue durée lié à l’essor du chalut, un filet traînant auquel certains acteurs attribuent la destruction des ressources halieutiques. L’analyse de cet épisode de violence permet ainsi d’enrichir la compréhension des résistances au changement technique en proposant une réflexion à partir du monde de la pêche, à rebours d’une historiographie qui s’est surtout intéressée aux machines industrielles (et agricoles, dans une moindre mesure).
La profession de constructeurs de navires dans les ports de commerce de la fin du xviie siècle aux années 1830
Authors: Plouviez David
Published: August 2021

Au xviiie siècle, les constructeurs de navires semblent se détacher progressivement du monde des métiers de la construction navale en acquérant une identité socio-professionnelle reposant sur des savoirs et savoir-faire spécifiques dont les modalités d’acquisition constituent un enjeu de la recherche. L’autonomisation de ce métier a lieu dans un contexte où la construction navale devient un secteur productif majeur en France, stimulé par l’essor des trafics océaniques et le cabotage européen. Les constructeurs sont désormais des entrepreneurs capables de diriger des chantiers, de traduire et d’anticiper les besoins de leurs commanditaires en développant une « pensée technique du navire » qui se manifeste par la réalisation de devis de plus en plus riches et de plans. Ce rôle majeur dans l’économie maritime permet aux constructeurs de développer une expertise sur laquelle s’appuient les pouvoirs locaux et l’État pour réguler le travail et la vie économique de la sphère portuaire.
Histoire d’un jeune homme
Authors: Vanoosthuyse François
Published: August 2021

Peu de textes dans l’histoire mondiale du roman ont été aussi profondément innovants que L’Éducation sentimentale. L’influence du roman de Flaubert sur la destinée ultérieure de son art, mais aussi d’autres arts mimétiques (peinture, photographie, cinéma), a été considérable, bien au-delà de Zola et de l’impressionnisme. C’est aussi un grand roman politique, plus fin et plus intéressant que ce que la correspondance de l’auteur pourrait laisser penser. Comme toutes les grandes fictions, il condense les conflits sociaux et les enjeux de l’histoire en quelques scènes d une puissance admirable. Enfin, comme son titre et son sous-titre (« Histoire d’un jeune homme ») le laissent entendre, ce roman est un roman d’amour. Mais il inaugure une nouvelle ère dans l’histoire du roman d’éducation et du roman sentimental. Sans renier ses racines romantiques, il opère une série de déplacements dont la force de dévoilement est considérable, sur un plan sociologique comme sur un plan psychologique.
Ce sont les aspects de L’Éducation sentimentale auxquels ce livre s’intéresse.
Monitoring of Chemical Resistance of New Grouting Materials
Authors: Figala Petr , Drochytka Rostislav , Černý Vit , Hermann Radek , Kolisko Jiří
Published: August 2021

This paper deals with the study of chemical resistance of new cement-based grout for invert grouting. The aim of this work is to verify new mixtures with specific admixtures. The study monitors resistance to external sulphate attack. Specimens were placed into sulphate solution 29.8 g∙l-1 (44 g∙l-1 Na2SO4) according to DIN19753 standard. Based on the results gained, new mixtures will be designed and optimized by addition of suitable secondary raw materials (fly ash, waste foundry sand, waste glass, waste filers).
Adhesives for the Installation of Cast Basalt Elements on Metal and Comparison of Properties when Using Different Types of Fillers
Authors: Hodul Jakub , Žlebek Tomáš , Mészárosová Lenka , Jakubík Aleš , Drochytka Rostislav
Published: August 2021

The polymeric adhesives for the installation of basalt elements on a metal base are designed primarily for environments with increased chemical and mechanical stress. They are composed of polymer resins (epoxy, polyurethane) as binders, as well as organic additives and mineral admixtures that mainly fulfill the function of filler. In all sectors of today's construction industry, maximum efficiency in the production of materials is required for sustainability purposes, which, however, must never be at the expense of the quality or the required performance. Due to these requirements, great emphasis is placed on the maximum use of secondary raw materials. Talc is used as the primary filler for polymer adhesives. Sawdust, tire rubber, and fly ash are used as secondary raw materials. The use of these in building supplies can positively affect some physical and mechanical properties of polymeric adhesives. Also, the use of secondary raw materials has the above-mentioned ecological benefit. Basic properties, such as bulk density and adhesion to both metallic and basalt elements, were monitored. The details of the cohesion of the adhesive with the bonded material, as well as the distribution of secondary raw materials in the polymer matrix, were assessed microscopically.
Analytical Techniques for Detection of Oil Presence in Mortar
Authors: Bauerová Pavla , Reiterman Pavel , Mácová Petra , Slížková Zuzana , Havelcová Martina , Mahun Andrii , Švarcová Silvie , Keppert Martin
Published: August 2021

Oils, e.g. linseed oil, has been used as mortar admixtures or components of lime-oil mastic since ancient times. The reason was either to increase the mortar durability and/or to prolong the mortar/mastic workability. Historic mortars are conventionally analyzed by means of X-ray diffraction and thermal analysis, but these methods are not able to detect the organic compounds directly. The goal of the present research was to evaluate the applicability of thermal analysis, infra-red spectroscopy, solid state NMR spectroscopy and gas chromatography for detection and possible quantification of linseed oil in prepared mortar containing, beyond the oil, just lime and calcite. Both applied spectroscopies were able not only detect the presence of oil but may be used also for study of the oil chemical transformation in the alkaline environment of the lime mortar. Thermal analysis is not able to identify kind of organic admixture, but when it is known that it is e.g. linseed oil, its quantification by help of Evolved Gas Analysis is very good. The results of gas chromatography of mortar’s extract are affected by the polymerization of oil in mortar. The total organic content analysis is providing good information about the total amount of organics in mortar. There in not any single method, which could provide all information about the oil admixture in mortar (kind of oil, content of oil, fate of oil after mortar’s mixing) by itself; the combination of techniques must be used.
Application of Nanoparticle of Merapi Volcanic Ash and Phosphate-Solubilizing Fungi in Improving Inceptisols Characteristics
Authors: Devnita Rina , Sandrawati Apong , Arifin Mahfud , Suryatmana Pujawati , Solihin Muhammad Amir , Wulandari Fikri Utami
Published: August 2021

Nanoparticles of Merapi volcanic ash and phosphate-solubilizing fungi were expected to function as ameliorants in improving some Inceptisols characteristics. Nanoparticles of volcanic ash were used in accelerating and streamlining the chemical reaction in the soil. Phosphate-solubilizing fungi were expected to assist the process of several soil reactions. The aim of the research was to improve some chemical characteristics like available P, cation exchange capacity, Fe, and Zn content of Inceptisols in Cilembu Village, Sumedang District, West Java Province, Indonesia. The research used a complete randomized experimental design in factorial with two factors. The first factor was the nanoparticle of Merapi volcanic ash consisted of four doses on soil weight percentage (0%, 2%, 4%, and 6%). The second factor was phosphate-solubilizing fungi consisted of two doses (without and 10 g.kg-1). The volcanic ash was collected from Mt. Merapi, Central Java, after the eruption of November 2010 and kept in the Laboratory of Soil Physics and Conservation in Faculty of Agriculture, Universitas Padjadjaran. The nanoparticle of volcanic ash was processed at Nanotechnology and Graphene Research Centre, Universitas Padjadjaran. The phosphate-solubilizing fungi were isolated from Inceptisols in Soil Microbiology Laboratory, Universitas Padjadjaran. These treatments were combined and mixed with soils and incubated for three months. Every one month during those three months of the incubation period, some soils were taken to be analyzed of available P, cation exchange capacity (CEC), available Fe, and available Zn. The result showed that there was no interaction between the nanoparticle of Merapi volcanic ash and phosphate-solubilizing fungi to parameters investigated except the CEC after two months of incubation. There was an effect of nanoparticle volcanic ash and phosphate-solubilizing fungi individually to available Fe dan Zn. There was a trend of increasing available P, and CEC and decreasing available Fe and Zn by the longer period of incubation.
Setting Time of Calcium Hydroxide from Indonesian Limestone Paste with Various Solvent Vehicle for Intracanal Medicament
Authors: Sidiqa Atia Nurul , Hanif Fadhilah , Zakaria Myrna Nurlatifah , Artilia Ira , Cahyanto Arief
Published: August 2021

Calcium hydroxide (Ca(OH)2 has been recently synthesized from natural Indonesian limestone to be used as an intracanal medicament for root canal infection. Ca(OH)2 is applied into the infected root canal in a non-setting paste form to release calcium and hydroxyl ions which elevates the pH and provide an antimicrobial effect to pathogenic bacteria. To form an injectable paste, Ca(OH)2 powder has to be mixed with a proper solvent to produce optimal consistency, ion dissociation, and maintain its property as a non-set material. Solvent is an important factor affecting ion dissociation and preserving its non-setting paste condition. The aim of this study is to synthesize Ca(OH)2 powder from Indonesian limestone, and evaluate the setting time of Ca(OH)2 paste from mixture of Ca(OH)2 powder synthesized from Indonesian limestone (limestone Ca(OH)2) with various solvent, to evaluate which solvent serve best to prevent the Ca(OH)2 paste from setting, to form an ideal paste be used as an intracanal medicament. This study consists of 5 groups (n=5); commercially Ca(OH)2 paste (Calcipex II) as positive control, Ca(OH)2 powder (Merck) + distilled water as negative control, limestone Ca(OH)2 powder + natrium carboxy methylcellulose (Na CMC) as group 1, limestone Ca(OH)2 powder + propylene glycol (PG) as group 2, and limestone Ca(OH)2 powder + polyethylene glycol (PEG) as group 3. Setting time evaluation was measured according to ISO 9917 by vicat needle in 37°C to mimic the physiological body condition. Results were analyzed by One Way Anova test and Post Hoc Tukey test. The result of this study showed that the setting time of Ca(OH)2 paste mixed with Na CMC solvent was 1:04 hours, PG 72:15 hours, and PEG did not harden until 7 days of observation. PEG is a hygroscopic high viscosity solvent, resulting in low and steady molecule interaction, thus prolonged its setting time. From this study it can be concluded that PEG inhibit Ca(OH)2 setting reaction up to 7 days and might be used as solvent for Ca(OH)2 paste as intracanal medicament.
Effect of Weak Magnetic Field on the Structure and Physical Properties of Chitosan Membranes
Authors: Rupiasih Ni Nyoman , Sumadiyasa Made , Putra I Ketut , Inten Gayatri Ida Ayu Putu
Published: August 2021

The purpose of this study was to evaluate the effect of weak magnetic fields on the structure and physical properties of chitosan (Ch) membranes. The membranes were prepared by a casting method using chitosan and a solvent of acetic acid. The magnetic field of 1.5 mT is applied during the membrane-forming reaction with administration times of 2, 4, 8, and 12 hours. The membranes formed were named M-2h, M-4h, M-8h, and M-12h, respectively. The chitosan membrane without magnetic fields is used as a control, namely M-0. The structure and physical properties of the membranes were examined using Fourier Transform Infra-Red (FTIR) spectrophotometer, water uptake test, dynamic mechanical analysis (DMA), and X-ray diffraction (XRD). The result showed that the membranes with magnetic fields are thicker compared to the control membrane. FTIR analysis revealed that some peaks of the membranes with magnetic fields shifted to the higher or lower wavenumber with increased or decreased absorption intensity. The membranes become stronger and more flexible; their degree of crystallinity increases as increasing the time of the magnetic fields' application, and their hydrophilicity improved. The membranes' crystal structure becomes more regular, and their degree of crystallinity increases as increasing the time of the application of the magnetic fields; and their mechanical properties such as ultimate tensile strength, tensile modulus, and elongation at break were improved. Those results explain that the structure and physical properties of chitosan membranes were significantly affected by the membrane-forming reaction's magnetic fields.