bluuebunny/crossref_metadata_2025 huggingface dataset:
Conseils à l’éleveur avant le transport des animaux à l’abattoir
Authors: Gilli-Dunoyer Pascale , Kieffer Jean-Pierre , Veauclin Nathalie
Published: December 2024

Il est de la responsabilité du vétérinaire sanitaire de conseiller les éleveurs sur la préparation de leurs animaux destinés à l’abattoir.

De leur présenter les informations et conséquences relatives à la transportabilité des animaux, à la propreté des cuirs, au tarissement des vaches laitières, au niveau de gestation des femelles et au bon engraissement des animaux, aux conséquences des pododermatites chez le poulets ou aux abcès caudaux chez le porc …

Ces conseils, tout en favorisant le bien-être des animaux, permettent aussi une meilleure valorisation économique des animaux.

Le respect des impératifs de protection animale à cette étape cruciale du transport vers l’abattoir est aussi important que celui des impératifs de santé animale et concourt à la qualité sanitaire des viandes produites.
L’accord Union européenne - Canada : quels risques pour les productions animales européennes ?
Authors: Trouvé Aurélie , Buczinski Baptiste , Chotteau Philippe , Rieu Michel
Published: December 2024

Le CETA (Comprehensive Economic and Trade Agreement) voté par le parlement européen en février 2017 va avoir des retombées certaines sur les agricultures européennes, notamment par la baisse forte de droits de douane encore importants.

C’est le cas en particulier en viande porcine et bovine, avec une forte hausse des contingents offerts à droits de douane nuls.

Le CETA offre également de nouvelles possibilités de révision à la baisse des normes sanitaires, phytosanitaires et environnementales, notamment l’interdiction de certaines substances de décontamination sur les produits d'origine animale, l’interdiction de traitement à la ractopamine des animaux, l’interdiction des activateurs de croissance hormonaux pour les bovins viande, les relatives restrictions dans l’importation, la consommation et la production d’OGM.

Un rapport très récent, effectué par des chercheurs des instituts techniques de l’élevage de ruminants, du porc et d’AgroParisTech montre ainsi que cet accord risque de fragiliser fortement les productions européennes de viande porcine et bovine, par des imports supplémentaires considérables de viande à droits de douane nuls à certaines périodes.

La concurrence outre-atlantique se ferait notamment sur certaines pièces de découpe, comme les côtes et aloyaux en viande bovine. Enfin, ces effets s’ajouteront à ceux de dizaines d’autres accords de libre-échange conclus ou en cours de négociation par l’UE avec d’autres pays ou régions du monde.
Intoxication chronique au cuivre chez des génisses
Authors: Guelou Kevin , Dupin Jean-Christophe , Tonnin Christophe , Liron Marie
Published: December 2024

Souvent rencontrée en élevage ovin, l’intoxication chronique par le cuivre peut également toucher les bovins, en particulier les jeunes animaux. Une fois la maladie identifiée, c’est la détermination des sources excessives de cuivre qui importe.

Les analyses sanguines pratiquées sur une des génisses permettent d’exclure une atteinte par des leptospires, alors que la mesure de la teneur sérique en cuivre de la génisse n°1748 met en évidence une teneur supérieure aux valeurs usuelles (22,14 µmol/L - valeurs usuelles 14-18 - ; ENV Toulouse).

Une intoxication chronique par le cuivre est confirmée par les résultats des teneurs en cuivre dans le foie des génisses n°1741 et 1748 (1115,6 et 1117,7 mg/kg de MS respectivement), et par les résultats des analyses histopathologiques.

L’excès de cuivre a plusieurs origines.
Il provient d’un aliment minéral normalement destiné aux animaux d’engraissement, un tourteau avec AMV (aliment minéral vitaminé) normalement destiné aux vaches laitières, et un sevrage tardif. Suite au retrait des deux aliments, aucun cas n’a été rapporté.

Cette étude de cas met en évidence la plus grande sensibilité du jeune par rapport à l’adulte.

Face à une telle situation, il convient de déterminer la teneur en cuivre et en molybdène des différents aliments apportés aux animaux, en particulier l’aliment d’allaitement.

La connaissance des produits médicamenteux administrés aux vaches avant vêlage, aux veaux à la naissance est aussi essentielle.
Les mycotoxines émergentes et ré-émergentes en France
Authors: Bailly Jean-Denis
Published: December 2024

Les mycotoxines sont des métabolites secondaires toxiques produits par certaines espèces fongiques au cours de leur développement. A l’heure actuelle, sept composés ou familles font l’objet de valeurs seuils fixées par la réglementation européenne. Ces toxines sont celles qui peuvent contaminer directement les aliments destinés à l’homme et que l’on peut retrouver dans les céréales, les fruits secs, les épices, …
Malgré cette réglementation, les mycotoxines posent un certain nombre de questions :
- Est-ce que d’autres toxines que celles réglementées peuvent avoir un effet sur la santé des hommes ou des animaux ?
Ainsi, la mise en évidence de toxines dites masquées ou modifiées, qui sont présentent dans les aliments en même temps que les toxines “natives”pose la question de la pertinence des valeurs seuils fixées jusqu’à présent.
De même, l’analyse des aliments montre la présence fréquente d’autres toxines pour lesquelles les données toxicologiques sont encore très parcellaires.

- Est-il possible que la répartition actuelle des toxines (nature et distribution géographique) change en lien avec les changements climatiques ?
Il est désormais acquis que les changements climatiques en cours auront un impact direct sur la répartition des mycotoxines, entraînant notamment l’apparition de toxines dans des zones jusque-là considérées comme indemnes. A l’heure actuelle, l’émergence possible de l’aflatoxine B1 en Europe préoccupe beaucoup les autorités sanitaires.
Il est aussi probable que des changements dans les pratiques agricoles puissent avoir un impact sur la nature et la fréquence de contamination des aliments pour animaux.
L’Agalactie Contagieuse Caprine en France : situation épidémiologique nationale mesures prophylactiques
Authors: Le Grand Dominique , Vialard Jaquemine , Treilles Michael , Tardy Florence , Poumarat François
Published: December 2024

L’Agalactie Contagieuse Caprine est une préoccupation sanitaire et économique majeure de la filière.
Les données VIGIMYC (réseau national d’épidemiosurveillance des mycoplasmoses des ruminants), établies entre 2006 et 2016, montrent que l’ACC est fréquente sur le territoire. Quatre mycoplasmes peuvent en être responsables et, sur les 5 dernières années, la fréquence moyenne d’isolement de ces différentes espèces a été la suivante : Mycoplasma (M.) mycoides subsp. capri (Mmc)(45%), M. capricolum subsp. capricolum (Mcc) (39%) M. putrefaciens (13%) et M. agalactiae (3%).
Les résultats de récentes études de terrain (projet MYCAPTANK) qui visent à établir un protocole d’évaluation du statut infectieux des troupeaux, hors épisodes cliniques,
ont permis la validation de techniques efficaces et simples de détection dans le lait de tank (qPCR sur lait de tank frais, congelé ou buvard FTA Elute® dans des conditions de protocole d'extraction spécifiques).

Compte tenu de la variabilité des cinétiques d'excrétion observées dans les élevages suivis, la présence d’une infection mycoplasmique ne peut être établie que sur la base d’une répétition des prélèvements de laits de tank.
La sensibilité aux antibiotiques des agents de l’ACC en France a assez peu évolué durant les 20 dernières années. La grande majorité des isolats de Mmc et Mcc restent encore sensibles à des concentrations très faibles de macrolides ou de tétracyclines. Cependant, vis-à-vis des macrolides, 10% à 20% d’isolats de Mcc ont acquis des résistances parfois très élevées.
Ration hivernale à base de foins
pour vaches laitières
Authors: Enjalbert Francis
Published: December 2024

En système AOP interdisant l’utilisation d’ensilages, la ration hivernale des vaches laitières est basée sur des foins, souvent séchés en grange pour assurer une bonne qualité.
Ces foins doivent à la fois assurer la fibrosité de la ration, et une part notable de la couverture des besoins.
Même s’ils sont de bonne qualité, une quantité importante de concentrés est nécessaire, y compris pour des niveaux de production modérés.

La complémentation concentrée peut être réalisée avec des matières premières et/ou des aliments composés du commerce respectant le cahier des charges.
L’anoxie du veau nouveau-né :
conduite diagnostique et thérapeutique
Authors: Meyer Gilles
Published: December 2024

L’anoxie du veau nouveau-né est un processus pathologique fréquent dont les facteurs déclenchants sont nombreux, peuvent être cumulatifs et interviennent lors de la gestation et/ou de la mise bas sur des animaux à risque.
Les conséquences d’un défaut d’oxygénation sont multiples ; ils touchent dans un premier temps le système cardiovasculaire et respiratoire, puis nerveux.
Le diagnostic repose essentiellement sur les circonstances d’apparition et sur l'examen clinique, compte tenu de la nécessité d’un traitement rapide.

La gestion de l’anoxie néonatale passe par une réanimation néonatale associée à des mesures de nursing dont le but est d’assurer le plus rapidement possible la ventilation pulmonaire et l’oxygénation correcte des tissus cérébraux.
Elle répond à des protocoles précis qu’il convient d’appliquer de manière ordonnée.
Nutrition et bien-être chez le cheval
Authors: Priymenko Nathalie
Published: December 2024

Le cheval est un herbivore qui passe environ les deux tiers de son temps à pâturer en se déplaçant. La domestication doit permettre le mieux possible de respecter ce schéma comportemental, donc ce comportement alimentaire.

Dans une prairie, le cheval domestique passe la plupart de son temps à manger de l’herbe, en préférant pâturer en groupe. L’ajout de grandes quantités de concentrés dans les rations « modernes » permet de couvrir les besoins du cheval sous un moindre volume d’aliments, mais diminue le temps dédié à l’ingestion, avec le risque d’engendrer une situation de stress pouvant mener à l’apparition d’ulcères voire de tics.

Pour limiter ce risque, même pour les chevaux en box ou au paddock, des ressources alimentaires doivent rester toujours accessibles, avec la possibilité en permanence d’accéder à de l’eau et à des fourrages (herbe, foin ou paille).
Mieux connaître les effets des pratiques
et des conditions culturales sur la qualité sanitaire des fourrages
Authors: Séguin Virginie , Lemauviel-Lavenant Servane , Gallard Yves , Bouchart Valérie , Ourry Alain , Garon David
Published: December 2024

Les bioaérosols (moisissures, mycotoxines, pollens, endotoxines) ainsi que les poussières, contenus dans les fourrages sont susceptibles de provoquer des maladies respiratoires chroniques telles que la Maladie Obstructive Récurrente des Voies Respiratoires (MORVR) chez le cheval.

Afin de diminuer la prévalence de ces maladies, il est nécessaire de déterminer les facteurs influençant la qualité sanitaire des fourrages.

Dans ce contexte, une expérimentation a été menée durant 3 années successives (2006-2009) à partir de fourrages issus d’une prairie permanente Normande sur laquelle différentes pratiques culturales et conditions climatiques ont été testées. Des fourrages commerciaux utilisés en alimentation équine (deux enrubannés et du foin de Crau) ont également été étudiés.

Ce travail a ainsi permis de mettre en évidence que certaines pratiques culturales (fourrage bottelé à 75% de matière sèche) ou conditions climatiques (pluie après coupe) entraînaient une dégradation de la qualité sanitaire des fourrages par une augmentation des poussières respirables, des organismes fongiques (en particulier Aspergillus fumigatus) et l’accumulation d’une mycotoxine, la zéaralénone.

A l’inverse, d’autres pratiques se sont avérées être favorables comme le séchage en grange ou l’enrubannage lorsque les conditions météorologiques ne permettent pas de récolter le foin à 85% de matière sèche comme cela est habituellement préconisé.
Comment parler vrai à l’enfant ?
Authors: Nasio Juan-David
Published: December 2024

Le développement physiologique, psychologique et social de l’enfant ne suit pas une ligne uniforme mais progresse par poussées discontinues, chacune étant une crise de croissance. Lors de chaque crise, l’enfant s’arrache au connu pour affronter l’inconnu : il quitte un état confortable mais inadapté à son âge, pour se lancer à la conquête de pouvoirs neufs, que ce soit sur le plan de la sensibilité, de l’intelligence, de la motricité ou encore de la socialisation.
Entrer en analyse pour s’en sortir
Authors: Ifergan Harry
Published: December 2024

L’interprétation d’un simple bégaiement aura produit chez mon patient l’expulsion d’un frère imaginaire figé dans sa matrice. Une fois percée cette poche psychique, l’enfant est advenu en tant que sujet pendant que je me muais en psychanalyste grâce à l’outil essentiel de notre travail : l’inconscient de l’analyste.
La traversée de la langue : du thème à la version
Authors: Maheu Dominique
Published: December 2024

Peut-on dire que l’enfant entre dans le langage en se mettant à parler ? Pour la psychanalyse, l’enfant répond avant tout. Qu’en est-il alors avec Anaïs, une enfant reçue en CMP qui, sans être enfermée dans un mutisme, ne répond pas ? À travers le récit d’une thérapie psychanalytique, certaines difficultés inhérentes à la rencontre du sujet avec la langue sont abordées. À rebours de l’exposé d’un cas perçu seulement dans un registre pathologique, le texte suit pas à pas les deux protagonistes, patient et thérapeute, au gré d’un cheminement improvisé où la boussole réside dans le principe freudien de la surdétermination du symptôme, et de son corollaire, l’accueil de la dimension d’inconnu et de sa mise en chantier dans le cadre d’une clinique sous transfert. L’expérience montre que le vacillement identitaire du clinicien s’avère ici constitutif d’un travail de construction des mots, où l’importance du ton, des sons dans leur proximité littérale avec le sens requière un rapport assoupli à son propre inconscient et l’exigence d’une écoute au gré. Par-delà le traitement symptomatique chez l’enfant, cette cure ouvre à d’autres questions : la langue première de l’infans serait-elle à refouler ou constitue-t-elle également un sésame nécessaire à l’entrée dans la langue qui s’apprend ? Si le choix de la clinique du sujet vise la liaison psychique entre corps et langage, cette démarche n’impliquerait-t-elle pas de prendre la mesure pour chaque patient de la façon dont il a vécu l’effraction de la langue ? Auquel cas, la cure pourrait aussi être une sorte d’expérience d’apprivoisement de la langue dans sa dimension hors sens.
Du ravage au rivage, un trou dans la langue
Authors: Escudero Lorena
Published: December 2024

À partir de l’exploration des pratiques de piercing et de tatouage c’est-à-dire de pratiques de corps liées à la trace et à la marque, l’autrice pose la question des voies de résolution possible du ravage maternel à la fois dans le moment adolescent et dans la cure d’une femme. De la donne première du ravage jusqu’à la séparation possible de celui-ci, par la lettre et l’écriture du corps, s’ouvrerait la possibilité d’un rivage.
A Queen City Legacy: 45 Years of Research in Pregnant Women with Insulin-Dependent Diabetes Mellitus, The Diabetes in Pregnancy Program Project Grant
Authors: Khoury Jane C. , Miodovnik Menachem , Mimouni Francis B. , Ehrlich Shelley , Szcznesiak Rhonda , Rosenn Barak
Published: December 2024

The Diabetes in Pregnancy Program Project Grant (PPG) was a 15-year program focused on enhancing the care for women with insulin-dependent diabetes mellitus (IDDM) during pregnancy and improving the well-being of their offspring. Launched in July 1978 at the University of Cincinnati, the PPG pursued a multifaceted research agenda encompassing basic science, animal and placental studies, and maternal and neonatal clinical trials to understand the physiological and pathophysiological aspects of IDDM during pregnancy. A total of 402 singleton pregnancies in 259 women with IDDM were enrolled prior to 10 weeks gestation over the 15-year period. Of the 402 pregnancies, there were 295 live births, 1 stillbirth, 4 neonatal deaths, and 15 infants were born with major congenital malformations. Central to the program's methodology was the management of diabetes during pregnancy, involving intensive insulin therapy and meticulous monitoring using the cutting-edge technology of the time to achieve glycemic control. The extensive research of the PPG yielded profound insights into the effects of maternal diabetes on embryonic and fetal development and neonatal health. Through animal studies, notably using pregnant sheep, the program clarified the mechanisms of fetal hypoxia and metabolic disorders. Clinical trials underscored the significance of early glycemic control in mitigating the risks of spontaneous abortions, congenital malformations, and neonatal complications. The program also examined the influence of pregnancy on the progression of microvascular diseases, the role of maternal weight and weight gain in pregnancy outcomes, and the distinctive growth patterns of fetuses in IDDM pregnancies. Furthermore, the PPG probed the incidence and underlying mechanisms of hypoglycemia during pregnancy and the heightened risk of obstetric complications in IDDM patients. Our findings established a foundation of knowledge to aid clinicians, researchers, and health care providers in best practices and ensure a lasting impact on the care of pregnant women with pregestational diabetes.

Key Points
HI/DMSO-Based Chemoselective Oxidative Halogenation of Pyrrolo[2,1-a]isoquinolines
Authors: Cui Hai-Lei
Published: December 2024

The application of HI in DMSO-based modifications of pyrrolo[2,1-a]isoquinoline derivatives has been explored. Selective chlorinations and iodinations of pyrrolo[2,1-a]isoquinolines have been achieved by using a HI/DMSO-based reaction system. A chlorination/aromatization cascade can be achieved by performing the reaction at 150 °C with NiCl2 as a chlorine source, whereas an iodination product was obtained by carrying out the reaction in PhCl/DMSO with HI at a lower temperature. Furthermore, it was found that the chemoselectivity can be tuned by the use of various additives, thereby providing methylthiolated or formylated pyrrolo[2,1-a]isoquinoline derivatives in acceptable yields.
Younger adolescents’ perspectives on book censorship: a case of Croatia
Authors: Lakuš Jelena , Martinović Ivana , Badurina Boris
Published: December 2024

This study explores the views of younger adolescents in Croatia regarding book censorship. Censorship, defined as systematic control of freedom of thought and expression, has a long history and continues to be relevant in modern times, targeting various age groups, particularly children and youth. The study explores historical and contemporary justifications for censoring books for young people, emphasizing the belief that children need protection from inappropriate content. This belief is rooted in the idea that children are intellectually and emotionally different from adults, necessitating a separate and protected period of childhood. The study involved a survey conducted among 62 seventh and eighth-grade students in Osijek, Croatia. Findings revealed that many adolescents have a superficial understanding of censorship, often associating it with the prohibition of offensive language. Despite this, over half of the respondents admitted to reading books deemed inappropriate for their age. The study highlights the need for further education on censorship and suggests that including adolescents in discussions about reading materials could be beneficial, as their perspectives often differ significantly from those of adults.
Influence of uniaxial tension on the electronic spectrum of antimony
Authors: Gaidukov Yu. P. , Grachev G. S. , Danilova N. P. , Pospelov Yu. A.
Published: December 2024

The influence of tension of whiskers to relative elongations of up to Δl/l0≈1% on the period of oscillations in the Shubnikov–de Haas effect in antimony has been investigated. The extremal cross sections of the Fermi surface were observed to undergo pronounced changes (by up to 50%). Good agreement was found when the experimental results were compared with theoretical calculations using the Falicov–Lin potential. Extrapolation of the results to larger tensile strains shows that electronic and hole transitions of order 2 1/2 should occur at Δl/l0≈3% and Δl/l0≈4.2%, respectively.
Pressure dependence of the initial splitting of the Co2+ ground state in Cs3CoCI5
Authors: Lukin S. N. , Teslya O. P. , Tsintsadze G. A.
Published: December 2024

We have used EPR measurements in a static magnetic field to determine the parameters of the spin Hamiltonian of the Co2+ ion in crystalline Cs3CoCl5 at 4.2 K: g∥ = 2.40±0.02; g⊥ = 2.31 ±0.01; D = − 4.30±0.05 cm−1. We have studied the influence of hydrostatic pressure on the magnitude of the initial splitting of the spin multiplet of the ground state of the Co2+ ion in its tetrahedral site. We observe a strong linear pressure dependence of the parameter D. We consider the relation between the function D(P) and the anisotropy of the compressibility of the crystal. We show that there is no magnetic ordering in Cs3CoCl5 at a pressure of 14 kbar down to a temperature of 2 K.
Deformation phenomena in a thin charged helium film
Authors: Tatarskii V. V. , Shikina N. I. , Shikin V. B.
Published: December 2024

The critical density nc of electrons in a thin film of helium with a thickness d in the presence of a metallic substrate is investigated. It is noted that the curve of the function nc(d) has a minimum in the region dmin∼10−4 cm. It is shown that in the region d < dmin the critical density must be determined taking into account the localization of electrons in a direction parallel to the surface of the helium and deformation phenomena accompanying this localization. A region of absolute instability and cluster solutions, which correspond to the existence of multielectronic dimples, whose radius R is smaller than the dimensions of the metallic substrate, is discovered for thicknesses d ∼d:min.
Influence of nonequilibrium phonons on the energy gap of superconductors
Authors: Bar’yakhtar V. G. , Seminozhenko V. P. , Shafranyuk S. E.
Published: December 2024

We consider the influence of isotropic phonon pumping at frequency Ω on the magnitude of the energy gap Δ in the spectrum of the quasiparticle excitations of a superconductor. It is shown that close to the superconducting transition temperature Tc, when the frequency is Ω < 2Δ, a strengthening of the superconductivity (an increase in Δ and in Tc) may occur due mainly to the direct influence of the distribution of nonequilibrium (real) phonons on the virtual Cooper pairing process. This mechanism is more effective than the mechanism of stimulated superconductivity of Éliashberg by the parameter [λ (Ω/Tc)(Ω τ ε)]−1 when Ω ≪ 2Δ (where λ is the BCS pairing constant and τε, is the energy relaxation time for the quasiparticles).
Exchange interaction constants in solid oxygen
Authors: Slyusarev V. A. , Freiman Yu. A. , Yankelevich R. P.
Published: December 2024

We have analyzed the magnetic properties of solid oxygen on the basis of the ab initio potential of van Hemert et al., and we have shown that the negative (ferromagnetic) interlayer exchange interaction obtained by van Hemert et al. is unrealistic.
Nonlinear waves on the surface of a layer of liquid helium in a transverse electric field. Nonlinear equilibrium forms
Authors: Zhakin A. I.
Published: December 2024

It is shown that two-dimensional solitary waves can exist on the surface of a layer of liquid helium in a transverse electric field. It is established that as the velocity of the wave decreases to zero it assumes a solitary equilibrium form (dimple, groove, protuberance, or depression). It is shown that in the subcritical region the electric field suppresses nonlinear oscillations and facilitates their development in the supercritical region.
Effect of low-temperature annealing on the structure and superconductivity of Nb–Ge films obtained by cathodic sputtering
Authors: Azhazha V. M. , Berdnik A. P. , Blinkin A. A. , Svinarenko A. P. , Tikhinskiĭ G. F. , Finkel’ V. A. , Ruzhichka I. , Samek F. , Prakharzhova Ya.
Published: December 2024

Films of Nb–Ge alloys are obtained by the method of cathodic sputtering in a wide range of concentrations. It is shown that the following phases form in the films: bcc solid solutions based on Nb; Nb3Ge in a lattice of A 15 type; tetragonal modification of Nb5Ge3; solid solution based on Ge. A correlation is established between the values of the lattice parameter and the Tc of the compound Nb3Ge. The effect of heat treatment in the temperature range 625–675°C on the critical temperature and the structure of Nb3Ge films is studied. It is shown that for film compositions close to the stoichiometric composition under certain conditions Tc can increase due to the process of atomic ordering.
Nonlinear theory of conductivity in quasi-one-dimensional molecular crystals
Authors: Brizhik L. S. , Davydov A. S.
Published: December 2024

A theory of conductivity in organic crystals is developed on the basis of nonlinear equations taking account of the interaction of excess electrons (holes) with local changes in the spacing between planar molecules in quasi-one-dimensional stacks. The electrons (holes) form pairs in the singlet state. These pairs are distributed equidistantly from each other and move as a whole at constant velocity, together with the local crystal deformations surrounding them.
Low-temperature anomalies in the temperature dependence of the strength and plasticity of metallic glasses
Authors: Tabachnikova E. D. , Bengus V. Z. , Startsev V. I.
Published: December 2024

An anomalous temperature dependence of the strength σf has been found in the metallic glasses Ni78Si8B14 (Vitrovac-0080) and Fe40Ni40B20 (Vitrovac-0040) in the temperature range T = 4.2−300 K, different from the generally accepted assumption of a constant σf in the region of heterogeneous plastic deformation. The anomalies observed are considered an indication of large residual internal stresses σjki in amorphous metal alloys which increase on decreasing the temperature and reach 0.01E (E is Young’s modulus) at 4.2 K. The low-temperature plasticity of the glasses point to an appreciable magnitude of the internal tangential stresses which can be produced by the presence of line defects. The hypothesis is made that in glasses which have low-temperature plasticity one can expect low-temperature anomalies in some other physical properties.
Theory of multiphonon spectra in semiconductor point contacts
Authors: Itskovich I. F. , Shekhter R. I.
Published: December 2024

We construct a theory of the nonlinear electrical conductivity of semiconductor point contacts that takes into account current carrier scattering and the electron–phonon interaction. We show that inelastic relaxation processes play a very important role in point contact spectra. Such relaxation arises from the successive emission of a number of phonons by hot electrons (multiphonon relaxation); the emission occurs a distance r from the contact, where r ∼ λϵ ≫d (d is the characteristic dimension of the point contact and λϵ is the electron inelastic relaxation distance). As a result the point contact spectrum contains peaks at multiples of the emitted phonon frequencies and at sums of those frequencies. This conclusion is in complete agreement with the experimental results of Pepper [M. Pepper, J. Phys. C 13, L709 (1980); J. Phys. C 13, L717 (1980)] for a metal–semiconductor heterocontact.
Non-Lorentzian power-law absorption on the wings of electron–ripplon resonance peaks
Authors: Dykman M. I.
Published: December 2024

The peaks in the conductivity of a two-dimensional electron crystal on the surface of helium, arising due to the excitation of capillary waves with wave vectors close to the reciprocal lattice vectors G, are examined. It is shown that at finite temperatures the conductivity in the wings of the peaks decreases as a function of the frequency detuning according to an unusual power law. The exponent depends strongly on the parameters of the electron system and on the order of the resonance (i.e., on the value of G/Gmin). This power law is a result of large long-wavelength fluctuations, which are characteristic for two-dimensional systems. In the case examined, the wings of the absorption peaks are formed due to processes in which several long-wavelength phonons of the electron crystal are created and annihilated.
Theory of phonon generation in superconductors with absorption of a high-frequency electromagnetic field
Authors: Shafranyuk S. E.
Published: December 2024

Using Keldysh’s technique, a kinetic equation is derived for the phonon distribution function in a clean (without impurities) superconductor, which takes into account the effect of an external high-frequency electromagnetic field on electron–phonon scattering. It is shown that the absorption of the field in acts of electron–phonon interactions induces generation of phonons. The frequency distribution of the phonons generated by pulsed fields is calculated for the cases Tc—T≪Tc and T≪Tc (Tc is the critical temperature of the superconductor).
The magnetic phase diagram of (C2H5NH3)2CuCl4
Authors: Bogdanov A. N. , Zhuravlev A. V. , Telepa V. T.
Published: December 2024

The magnetic phase diagram of the easy-axis antiferromagnet (C2H5NH3)2CuCl4 has been studied in a field parallel to the axis of easy magnetization and in an inclined field. It has been shown that over a certain temperature range the transition from the antiferromagnetic to the paramagnetic phase is realized as a first order phase transition. The H–T diagrams for antiferromagnets with spin S = 1/2 are classified.
Shubnikov–de Haas oscillations in synthetic metals based on graphite intercalation compounds
Authors: Brandt N. B. , Kuvshinnikov S. V. , Ionov S. G. , Mukhanov V. A.
Published: December 2024

Quantum oscillation effects have been investigated in synthesized very perfect quasisingle crystals of low stage graphite intercalation compounds of the acceptor type. The parameters of the energy spectrum of the current carriers in these compounds have been determined. The effect of a sharp decrease of amplitude of Shubnikov–de Haas (ShdH) oscillations with tilt of the magnetic field away from the C axis has been discovered in these compounds; this is connected with the two-dimensional nature of the motion of the current carriers.
Model for an anti-isostructural phase transition coupled with ordering
Authors: Kovarskii V. L. , Leont’eva A. V. , Sukharevskii B. Ya.
Published: December 2024

We consider the possible existence of a cubic invariant in the Landau potential for an interstitial alloy (a binary alloy consisting of particles and “holes”). Using the example of a three-sublattice planar triangular lattice in the Bragg–Williams approximation, we study the role of three-particle interactions in the formation of an anti-isostructural phase. We present the results of numerical calculations for the phase diagram of the model and the temperature dependence of the order parameter. We suggest a possible realization of the situation considered in solid hydrogen.
Analog of the Andreev reflection of quasiparticles in low-dimensional conductors with a charge-density wave
Authors: Kasatkin A. L. , Pashitskiĭ É. A.
Published: December 2024

It is shown that in low-temperature conductors with a charge-density wave (CDW) particles are reflected by inhomogeneities of the order parameter, analogously to the case of Andreev reflection in inhomogeneous superconductors, which creates an excess electrical and thermal resistance in conductors with a nonuniform CDW.
Thermodynamic properties of ethylene and propylene in the vicinity of the triple point
Authors: Porkhun L. D.
Published: December 2024

An experimental apparatus for measuring the density of solidified gases is described. The density of solid ethylene and propylene is determined, and their coefficients of volume expansion are determined in the temperature intervals 78–104 K and 78–87 K, respectively. The p–T dependence on the melting line of these substances is measured. The density of the liquid phase and the coefficients of volume expansion of the investigated hydrocarbons are determined near the triple point. The heat of the solid–liquid phase transition for ethylene and propylene at the triple point is calculated according to the Clausius–Clapeyron equation.
Low temperature internal friction in crystalline argon
Authors: Leont’eva A. V. , Marinin G. A. , Oberemchenko I. A.
Published: December 2024

We report an experimental study of the low frequency internal friction in argon at low temperatures down to 4.2 K. A peak is observed in the low frequency internal friction at a temperature of 24 K, at which the argon, according to data on the relaxation of stress and uniaxial active strain, is characterized by a Peierls mechanism of plastic deformation and by a brittle failure mode.
Ortho–para composition dependence of the conversion rate in liquid hydrogen
Authors: Milenko Yu. Ya. , Sibileva R. M.
Published: December 2024

The intrinsic rate of ortho-para conversion in liquid hydrogen has been studied experimentally as a function of the o–p composition over a wide range of ortho concentrations (8–75%), at a temperature of T = 20.34 K. We find a deviation from the relation dc/dt = −kc2 When the results obtained are described in terms of this equation, the value of k is reduced by some 25% on going from ortho to para hydrogen.
Impact of psychological fear and media on infectious diseases induced by carriers
Authors: Pal Kalyan Kumar , Rai Rajanish Kumar , Tiwari Pankaj Kumar
Published: December 2024

To manage risks and mitigate the transmission of infectious diseases, individuals often adopt strategies aimed at reducing interpersonal contact by implementing precautionary measures within their daily routines. These behavioral adjustments reduce the disease transmission rates. In this study, we present a novel mathematical model delineating diseases induced by carriers, incorporating multifaceted factors, such as psychological fear, media impact, and sanitation interventions. We analyze the system’s dynamics using analytical as well as numerical methods. We find that rapid dissemination of information through social media can lead to oscillations, mitigated by introducing a sufficient baseline number of advertisements. The system undergoes a transition from the disease-free to endemic states via a transcritical bifurcation, occurring when the basic reproduction number surpasses unity. Through a Hopf bifurcation, the system shifts from a stable state to limit cycle oscillations once the growth rate of advertisements is above a critical value. Heightened levels of fear attenuate these oscillations, thereby stabilizing the system at an endemic state. Moreover, the system experiences periodic, higher-periodic, and chaotic oscillations when the growth rate of advertisements varies seasonally. Overall, our findings underscore the significant role of psychological fear, media influence, and sanitation measures in suppressing the prevalence of diseases induced by carriers from the targeted population.
Cross-facility absolute charge calibration of scintillating screens for laser wakefield accelerated beam diagnostics
Authors: Chiang Chen-Wei , Chou Ming-Chang , Lee An-Ping , Wang Yu-Qian , Wang Jhih-Jia , Lin Ming-Wei , Lau Wai-Keung , Chou Shao-Wei
Published: December 2024

Scintillation screens are widely used to diagnose high-charge density, low-average current electron beams from laser wakefield accelerators (LWFAs). However, the absolute response between emitted photons and electron charge has only been calibrated at a limited number of facilities, and there have been discrepancies between these calibrations. In this report, we comprehensively revised the absolute charge calibration of two high relative brightness scintillating screens of LANEX Regular (Carestream) and PI200 (Mitsubishi) by employing the high-brightness photoinjector at the National Synchrotron Radiation Research Center (NSRRC), which provides electron beams with variable charges (50–350 pC per pulse) and energies (26.55, 34.50, 42.10 MeV). Our results show that the energy-independent fluorescence efficiency of LANEX Regular and PI200 is (7.39 ± 0.38) × 109 and (2.04 ± 0.04) × 1010 photons/sr/pC, respectively, and both screens retained over 98.5% efficiency at accumulated charge densities up to 500 nC/mm2. These results provide a robust framework for applying the scintillation screens in LWFA diagnostics to enhance accuracy and reliability in electron beam characterization.
Tracking of atomic planes in atom probe tomography
Authors: Koelling Sebastian , Assali Simone , Nadal Guillaume , Isheim Dieter , Seidman David N. , Moutanabbir Oussama
Published: December 2024

Atom probe tomography is a ubiquitous method in materials science and engineering capable of revealing the atomic-level three-dimensional composition of a plethora of materials. Beside the nature of atoms forming the analyzed material, atom probe data are also known to contain information on the crystallography. In particular, remnants of the atomic plane sets forming on the surface of the tip-shaped samples are commonly found in atom probe data sets of crystalline metallic materials. The plane remnants can be utilized to correlate the nano-scale chemical analysis that atom probe tomography provides with the crystallographic structure on the same scale. We describe a protocol to reveal and track the atomic planes systematically from raw atom probe data. We demonstrate for both metals and semiconductors that the extracted crystallographic can be used to calibrate a dynamic reconstruction of the respective data set acquired in atom probe tomography. Furthermore, we utilize the crystal planes to make precise measurements of layer thicknesses in atom probe data of semiconductor heterostructures.
Multi-objective optimization and performance analysis of the splitter blades in a multiphase pump
Authors: He Chunpei , Han Wei , Li Rennian , Dong Yifan , Zhang Yukun
Published: December 2024

Helical axial-flow multiphase pumps are core devices for developing deep-sea oil and gas, but the complex two-phase flow inside such pumps affects their transport stability. As reported here, for enhanced flow characteristics, splitter blades were added at the noncoincidence area of the impeller tail by using a multi-objective optimization method, and their impact on the pump performance was explored in comparison with the original model. The results indicate that Gaussian process regression combined with particle swarm optimization accurately predicts the pump external characteristics. Under an inlet gas volume fraction of 30%, the optimized model increases the head coefficient by 22.2% without reducing efficiency. Although splitter blades enhance the impeller tail, they intensify gas-phase accumulation at the tail. The optimized model promotes more-uniform two-phase flow in the channels, with the axial velocity uniformity of the gas phase and liquid phase improving by 15.1% and 9.5% and the average velocity angle increasing by 12.3° and 8.3° under an inlet gas volume fraction of 30%.
Metaparticles: Computationally engineered nanomaterials with tunable and responsive properties
Authors: Paesani Massimiliano , Ilie Ioana M.
Published: December 2024

In simulations, particles are traditionally treated as rigid platforms with variable sizes, shapes, and interaction parameters. While this representation is applicable for rigid core platforms, particles consisting of soft platforms (e.g., micelles, polymers, elastomers, and lipids) inevitably deform upon application of external stress. We introduce a generic model for flexible particles, which we refer to as MetaParticles (MPs). These particles have tunable properties, can respond to applied tension, and can deform. A MP is represented as a collection of Lennard-Jones beads interconnected by spring-like potentials. We model a series of MPs of variable sizes and symmetries, which we subject to external stress, followed by relaxation upon stress release. The positions and the orientations of the individual beads are propagated by Brownian dynamics. The simulations show that the mechanical properties of the MPs vary with size, bead arrangement, and area of applied stress, and share an elastomer-like response to applied stress. Furthermore, MPs deform following different mechanisms, i.e., small MPs change shape in one step, while larger ones follow a multi-step deformation pathway, with internal rearrangements of the beads. This model is the first step toward the development and understanding of particles with adaptable properties with applications in the biomedical field and in the design of bioinspired metamaterials.
Degradation of performance in ICF implosions due to Rayleigh–Taylor instabilities: A Hamiltonian perspective
Authors: Ruiz D. E.
Published: December 2024

The Rayleigh–Taylor instability (RTI) is an ubiquitous phenomenon that occurs in inertial-confinement-fusion (ICF) implosions and is recognized as an important limiting factor of ICF performance. To analytically understand the RTI dynamics and its impact on ICF capsule implosions, we develop a first-principle variational theory that describes an imploding spherical shell undergoing RTI. The model is based on a thin-shell approximation and includes the dynamical coupling between the imploding spherical shell and an adiabatically compressed fluid within its interior. Using a quasilinear analysis, we study the degradation trends of key ICF performance metrics (e.g., stagnation pressure, residual kinetic energy, and areal density) as functions of initial RTI parameters (e.g., the initial amplitude and Legendre mode), as well as the 1D implosion characteristics (e.g., the convergence ratio). We compare analytical results from the theory against nonlinear results obtained by numerically integrating the governing equations of this reduced model. Our findings emphasize the need to incorporate polar flows in the calculation of residual kinetic energy and demonstrate that higher convergence ratios in ICF implosions lead to significantly greater degradation of key performance metrics.
Evaluating modeling approaches for Rb-129Xe spin-exchange optical pumping and the effect of Rb vapor density heterogeneity
Authors: Ball J. E. , Wild J. M. , Norquay G.
Published: December 2024

The applicability of commonly used 129Xe nuclear polarization (PXe) buildup models to large optical cell polarizers, which operate at lower gas pressures when compared to small cell polarizers for which spin-exchange optical pumping (SEOP) models were originally developed, has yet to be systematically evaluated. In addition, spatial heterogeneity of Rb vapor density ([Rb]) and its impact on SEOP in low pressure, large optical cell polarizers remains poorly understood. In this theoretical study, it was shown that 1D analytical and numerical PXe buildup models yield diverging PXe and critical flow rate values at low flow rates and high laser absorption, contributing to the discrepancy between theoretical and experimentally measured production rates. Additionally, it was found that [Rb] heterogeneity leads to lower PXe buildup and an undesirable increase in optimal cell temperature, while the optimal laser absorption remains relatively unchanged. The updated simulation framework presented here can be utilized to model other SEOP systems.
Optimizing waste heat recovery in a dual-fuel diesel engine through thermoelectric generation and heat pipe integration
Authors: Khayum Naseem , Anbarasu S. , Murugan S.
Published: December 2024

Thermoelectric generation (TEG) is a solid-state technique that efficiently captures waste heat from the exhaust of internal combustion engines. Heat pipes are passive energy recovery devices that work with minimum temperature decrease, making them very efficient. TEGs and heat pipes are distinguished by their absence of mechanical components and noiseless performance, relying solely on thermal energy for operation. This research examines the practicality of combining a device for thermoelectric generation with a heat pipe (TEG–heat pipe system) to capture and utilize wasted heat from a stationary diesel engine that operates in dual-fuel mode. The engine uses waste cooking oil methyl ester as a pilot fuel and introduces biogas (0.75 kg/h) as an induction fuel. The performance of the system was evaluated by conducting experiments at different engine loads, specifically 1, 2, and 3 kW. The experiments aimed to analyze the impact of integrating a heat pipe into the system. The findings suggest that incorporating a heat pipe with the thermoelectric generator (TEG) greatly increased the temperature difference between the modules. However, the amount of heat supplied to the modules reduced as the heat exchanger lengthened. In summary, the integration of TEG–heat pipe has shown the ability to produce additional electrical power from engine exhaust, hence enhancing energy efficiency.
Tapping into tissue bioelectromechanics: Electroactive biopolymers for dynamic tissue engineering
Authors: Burgess Matthew K. , Nair Malavika
Published: December 2024

The success of tissue engineering constructs in restoring healthy tissue function is driven by the interplay of cells with their microenvironmental cues. Therefore, the design of tissue engineering materials is typically guided by ensuring adequate mimicry and regulation of the dynamic biochemical, mechanical, and electrical interactions that occur in the cellular and extracellular milieu. In this work, we introduce the current approaches and limitations to static and stimuli-responsive tissue engineering, with a focus on electroactive materials. We consider the mechanisms of material interactions and the development of electroactive polymers for soft robotics to address how these developments can pave the way for ‘smart’ tissue engineering devices that recapitulate key elements of tissue bioelectromechanics. By highlighting the successes and current challenges in the materials development to support such dynamic devices, we summarize our findings with design guidelines to direct the future development of clinically translatable and efficacious tissue engineering constructs with the dynamic functionality of soft robots.
Flow structure consistency analysis between vortex particle method and detached eddy simulation method based on modal decomposition
Authors: Meng Xiaoxuan , Bai Junqiang , Chang Min , Hui Zhe
Published: December 2024

The vortex particle method (VPM) has been widely used for rotor wake simulation due to its lower numerical dissipation and computational cost. However, the data consistency of flow structure between VPM and high-fidelity methods still lacks systematic analysis. In this paper, the flow over the Caradonna–Tung rotor in hover is simulated using both the VPM and high-fidelity detached eddy simulation (DES) methods to compare the consistency of the load distribution and wake evolution. Two modal decomposition methods, proper orthogonal decomposition (POD) and dynamic mode decomposition (DMD), are introduced to decompose the vorticity field into POD and DMD modes and then analyze the consistency of flow structure described by these modes between VPM and DES results. The research on basic features of load distribution and wake evolution indicates that the VPM can obtain results with accuracy similar to DES results and with less computation cost. The analysis of flow structure consistency finds that VPM has good consistency with the high-fidelity DES method on the dominated flow structures whose characteristic frequencies are rotation frequency, blade passing frequency, and their frequency multiplication.