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1.
Can Vet J ; 65(8): 802-807, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-39091471

RESUMEN

Objective: The objective of this prospective observational research project was to have dairy producers use and assess the utility of a cull cow evaluation form. Animals: Cull dairy cows. Procedure: Veterinarians were recruited to enrol a purposively selected group of dairy producers into a project to evaluate a cull cow evaluation form. Producers were provided with evaluation forms and asked to complete a form for every cow they culled from their herd from January to June 2017, inclusive. Results: A total of 44 producers used the form to record information on 323 cows prior to transport. Conclusion and clinical relevance: Despite the completion of 323 forms, only ~1/3 were completed fully, with compliance highest for body condition score, lameness, and temperature recordings (> 90% of forms). A cull cow evaluation form may improve the thoroughness and consistency of dairy producer assessment of cull dairy cows for fitness for transport.


Un formulaire d'évaluation pour aider les producteurs laitiers à évaluer systématiquement les vaches avant la réforme. Objectif: L'objectif de ce projet de recherche observationnelle prospective était d'amener les producteurs laitiers à utiliser et à évaluer l'utilité d'un formulaire d'évaluation des vaches de réforme. Animaux: Vaches laitières réformées. Procédure: Des vétérinaires ont été recrutés pour inscrire un groupe de producteurs laitiers sélectionnés à dessein dans un projet visant à évaluer un formulaire d'évaluation des vaches réformées. Les producteurs ont reçu des formulaires d'évaluation et ont été invités à remplir un formulaire pour chaque vache qu'ils ont éliminée de leur troupeau de janvier à juin 2017 inclusivement. Résultats: Au total, 44 producteurs ont utilisé le formulaire pour enregistrer des informations sur 323 vaches avant le transport. Conclusion et pertinence clinique: Malgré la complétion de 323 formulaires, seulement environ 1/3 ont été entièrement remplis, avec une conformité plus élevée pour le score d'état corporel, les boiteries et les enregistrements de température (> 90 % des formulaires). Un formulaire d'évaluation des vaches laitières réformées peut améliorer la rigueur et la cohérence de l'évaluation par le producteur laitier des vaches laitières réformées quant à leur aptitude au transport.(Traduit par Dr Serge Messier).


Asunto(s)
Industria Lechera , Animales , Bovinos , Femenino , Industria Lechera/métodos , Sacrificio de Animales , Estudios Prospectivos , Transportes , Enfermedades de los Bovinos/diagnóstico , Cojera Animal
2.
Phys Rev Lett ; 132(17): 176702, 2024 Apr 26.
Artículo en Inglés | MEDLINE | ID: mdl-38728708

RESUMEN

We formulate a Landau theory for altermagnets, a class of collinear compensated magnets with spin-split bands. Starting from the nonrelativistic limit, this Landau theory goes beyond a conventional analysis by including spin-space symmetries, providing a simple framework for understanding the key features of this family of materials. We find a set of multipolar secondary order parameters connecting existing ideas about the spin symmetries of these systems, their order parameters, and the effect of nonzero spin-orbit coupling. We account for several features of canonical altermagnets such as RuO_{2}, MnTe, and CuF_{2} that go beyond symmetry alone, relating the order parameter to key observables such as magnetization, anomalous Hall conductivity, and magnetoelastic and magneto-optical probes. Finally, we comment on generalizations of our framework to a wider family of exotic magnetic systems derived from the zero spin-orbit coupled limit.

3.
Phys Rev Lett ; 130(26): 266702, 2023 Jun 30.
Artículo en Inglés | MEDLINE | ID: mdl-37450813

RESUMEN

Accidental ground state degeneracies-those not a consequence of global symmetries of the Hamiltonian-are inevitably lifted by fluctuations, often leading to long-range order, a phenomenon known as "order-by-disorder" (ObD). The detection and characterization of ObD in real materials currently lacks clear, qualitative signatures that distinguish ObD from conventional energetic selection. We show that for order by thermal disorder (ObTD) such a signature exists: a characteristic temperature dependence of the fluctuation-induced pseudo-Goldstone gap. We demonstrate this in a minimal two-dimensional model that exhibits ObTD, the ferromagnetic Heisenberg-compass model on a square lattice. Using spin-dynamics simulations and self-consistent mean-field calculations, we determine the pseudo-Goldstone gap, Δ, and show that at low temperatures it scales as the square root of temperature, sqrt[T]. We establish that a power-law temperature dependence of the gap is a general consequence of ObTD, showing that all key features of this physics can be captured in a simple model of a particle moving in an effective potential generated by the fluctuation-induced free energy.


Asunto(s)
Frío , Física , Temperatura
4.
Ann Plast Surg ; 82(6S Suppl 5): S394-S398, 2019 06.
Artículo en Inglés | MEDLINE | ID: mdl-30694845

RESUMEN

PURPOSE: Acellular dermal matrices (ADMs) are commonly used for immediate breast reconstruction after skin-sparing mastectomy (SSM). Regnault grades 2 and 3 ptotic breasts feature significant mastectomy flap redundancy that may be incorporated into the reconstruction. This allows surgeons to use patients' de-epithelialized inferior dermal pedicle instead of ADM. METHODS: All consecutive SSM patients with Regnault grade 2 or 3 ptosis who underwent Passot-type immediate breast reconstruction (IBBR) with tissue expanders (TEs) and de-epithelialized inferior dermal pedicle without an ADM were included. Patient data from the electronic medical record, clinical photographs, and a comparative cost analysis of ADM versus additional operative time are provided. RESULTS: Thirty-eight patients with an average age of 52.7 years, weight 210.5 lb, and body mass index of 35.1 kg/m were treated (34 bilateral, 4 unilateral; 72 reconstructed breasts). Average mastectomy specimens weighed 962.8 g. Tissue expanders were filled to 265.0 mL (41.6% capacity) intraoperatively, and final implant volume averaged 710.9 ± 118.5 mL after an average of 628.6 ± 74.1-mL expansion. Operative times for Passot-type IBBR was 124.3 ± 37.7 versus 92.5 ± 27.9 minutes (P = 0.0001) for submuscular TE placement with ADM. The operative technique is described in detail. There were 8 TE explantations (21.1%) included: intractable infection (10.5%; n = 4), symptomatic capsular contracture (7.9%; n = 3), and spontaneous TE deflation (2.6%; n = 1). All but 3 patients (92.1%) successfully completed Passot reconstruction, with 2 patients declining salvage latissimus dorsi flap reconstruction and 1 patient lost to follow-up. Total cost savings in this case series was $89,724 ($2361 ± $3529/case). CONCLUSIONS: Additional prospective comparison studies are needed to determine whether Passot-type IBBR results in higher complication rates than conventional IBBR with ADM in this challenging patient population. Passot-type IBR after SSM is safe, demonstrates acceptable rates of successful breast reconstruction, confers cost savings by obviating the use of ADM, and provides favorable aesthetic results.


Asunto(s)
Dermis Acelular , Mamoplastia/métodos , Mastectomía/métodos , Satisfacción del Paciente , Expansión de Tejido/métodos , Adulto , Neoplasias de la Mama/cirugía , Estética , Femenino , Humanos , Persona de Mediana Edad , Trasplante de Piel/métodos , Factores de Tiempo
5.
Phys Rev Lett ; 121(23): 237201, 2018 Dec 07.
Artículo en Inglés | MEDLINE | ID: mdl-30576168

RESUMEN

In systems with competing interactions, continuous degeneracies can appear which are accidental, in that they are not related to any symmetry of the Hamiltonian. Accordingly, the pseudo-Goldstone modes associated with these degeneracies are also unprotected. Indeed, through a process known as "order-by-quantum disorder," quantum zero-point fluctuations can lift the degeneracy and induce a gap for these modes. We show that this gap can be exactly computed at leading order in 1/S in spin-wave theory from the mean curvature of the classical and quantum zero-point energies-without the need to consider any spin-wave interactions. We confirm this equivalence through direct calculations of the spin-wave spectrum to O(1/S^{2}) in a wide variety of theoretically and experimentally relevant quantum spin models. We prove this equivalence through the use of an exact sum rule that provides the required mixing of different orders of 1/S. Finally, we discuss some implications for several leading order-by-quantum-disorder candidate materials, clarifying the expected pseudo-Goldstone gap sizes in Er_{2}Ti_{2}O_{7} and Ca_{3}Fe_{2}Ge_{3}O_{12}.

6.
J Dairy Sci ; 101(11): 10580-10588, 2018 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-30197134

RESUMEN

Dairy cows are culled from the herd for a variety of reasons, the most common being fertility problems, low milk production, or udder problems. Disease and injury can contribute to the decision to cull either directly, or indirectly, by causing fertility or production problems, leading to culling. Disease or injury may also affect the cow's ability to handle the stress of transportation and may increase the risk for reduced welfare. The purpose of this study was to determine the general condition of culled dairy cows sold at Ontario auction markets, to quantify the frequency of culled cows in poor condition sold at these auctions, and to determine how this relates to the sale price of the cow. Data were collected on 4,460 culled dairy cows, sold at 3 Ontario auction markets, over a continuous 16-wk study period. Observers assessed the general condition of dairy cows entering the sales ring by recording each individual cow's hock injury score, body condition score (BCS), gait score, and tail score, in accordance with 2017 Canadian proAction Animal Care guidelines. Each cow's body weight, breed, and sale price were also recorded. Results showed that 27.2% of culled cows scored had unacceptable hock injuries, 40.5% had a BCS ≤2, 72.7% had an abnormal gait, and 12.5% had docked tails. Culled cows with a BCS ≤2 sold for $0.20 less/kg compared with those with a BCS >2, which equated to an overall average loss of $117 per cow. Cows with an abnormal gait sold for $0.05 less/kg compared with culled cows with a normal gait, which equated to an overall average loss of $32.45 per cow. There was no difference in the sale price depending on hock injury score or the presence or absence of a full tail. The main issues identified in this study were the high prevalence of low body condition and abnormal gait, indicating that the welfare of these cows may be at risk. Additionally, cows with low BCS or abnormal gait sold for a lower price compared with cows that were in good condition, leading to reduced potential profit for the producer.


Asunto(s)
Bienestar del Animal , Enfermedades de los Bovinos/prevención & control , Fertilidad , Vivienda para Animales/normas , Leche/metabolismo , Reproducción , Sacrificio de Animales , Crianza de Animales Domésticos , Animales , Peso Corporal , Bovinos , Comercio , Industria Lechera/economía , Industria Lechera/métodos , Femenino , Lactancia , Ontario , Tarso Animal/lesiones , Transportes
7.
Nat Commun ; 7: 12234, 2016 07 29.
Artículo en Inglés | MEDLINE | ID: mdl-27470199

RESUMEN

We present a new classical spin liquid on the pyrochlore lattice by extending spin ice with further neighbour interactions. We find that this disorder-free spin model exhibits a form of dynamical heterogeneity with extremely slow relaxation for some spins, while others fluctuate quickly down to zero temperature. We thus call this state spin slush, in analogy to the heterogeneous mixture of solid and liquid water. This behaviour is driven by the structure of the ground-state manifold which extends the celebrated two-in/two-out ice states to include branching structures built from three-in/one-out, three-out/one-in and all-in/all-out tetrahedra defects. Distinctive liquid-like patterns in the magnetic correlations serve as a signature of this intermediate range order. Possible applications to materials as well the effects of quantum tunnelling are discussed.

8.
Chin Clin Oncol ; 5(1): 4, 2016 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-26932428

RESUMEN

BACKGROUND: Neuroendocrine tumors (NETs) are rare tumors that often present with vague symptoms. Identification and localization of the primary NET can be challenging and the true incidence remains unclear. These patients have been thought to have a poor prognosis compared to those patients with a known primary. Therefore, traditionally the treatments for patients with unknown primaries have been passive and directed towards symptom control and/or cytoreduction of metastatic disease. We hypothesized that NET of unknown primary are predominantly low-grade and easily located surgically and therefore are amendable to surgical debulking and cytoreduction, which will likely increase survival in these patients. METHODS: The charts for all 342 surgical patients, seen in our clinic at Ochsner-Kenner between 1/2009 and 9/2012 were retrospectively reviewed to determine which patients had a pre-operative diagnosis of a "NET with unknown primary". Twenty-two patients (6.4%) were identified. For these patients, the rate of successful surgical exploration in which a primary site was identified was recorded. Survival for these "unknown primary" patients were compared to a large similar group of NET patients from a recent study collected from this same Ochsner clinic group. RESULTS: Twenty-two (22/342, 6.4%) NET patients with a pre-operative diagnosis of an unknown primary were explored and cytoreduced. The primary tumor site was identified in all 22 patients (100%). The primary sites identified for these patients were 19 small intestines (86.4%) and 3 pancreatic (13.6%). All 22 patients had low-grade tumors and all were still alive as of 9/2012, not allowing for a survival curve to be generated. CONCLUSIONS: Unknown primary NETs are not associated with a poor prognosis as previously reported. Timely surgical exploration and debulking always results in the identification of the primary and a maximum cytoreduction. Early surgical exploration with aggressive debulking is indicated for the treatment of these patients, as for the known counterpart.


Asunto(s)
Procedimientos Quirúrgicos de Citorreducción/métodos , Neoplasias Primarias Desconocidas/cirugía , Tumores Neuroendocrinos/cirugía , Adulto , Anciano , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Clasificación del Tumor , Neoplasias Primarias Desconocidas/patología , Tumores Neuroendocrinos/patología , Pronóstico , Estudios Retrospectivos , Tasa de Supervivencia
9.
Phys Rev Lett ; 115(26): 267208, 2015 Dec 31.
Artículo en Inglés | MEDLINE | ID: mdl-26765024

RESUMEN

If magnetic frustration is most commonly known for undermining long-range order, as famously illustrated by spin liquids, the ability of matter to develop new collective mechanisms in order to fight frustration is perhaps no less fascinating, providing an avenue for the exploration and discovery of unconventional behaviors. Here, we study a realistic minimal model where a number of such mechanisms converge, which, incidentally, pertain to the perplexing quantum spin ice candidate Yb(2)Ti(2)O(7). Specifically, we explain how thermal and quantum fluctuations, optimized by order-by-disorder selection, conspire to expand the stability region of a degenerate continuous U(1) manifold against the classical splayed ferromagnetic ground state that is displayed by the sister compound Yb(2)Ti(2)O(7). The resulting competition gives rise to multiple phase transitions, in striking similitude with recent experiments on Yb(2)Ti(2)O(7) [Lhotel et al., Phys. Rev. B 89, 224419 (2014)]. By combining a gamut of numerical techniques, we obtain compelling evidence that such multiphase competition is a natural engine for the substantial sample-to-sample variability observed in Yb(2)Ti(2)O(7) and is the missing key to ultimately understand the intrinsic properties of this material. As a corollary, our work offers a pertinent illustration of the influence of chemical pressure in rare-earth pyrochlores.

10.
Phys Rev Lett ; 112(7): 077204, 2014 Feb 21.
Artículo en Inglés | MEDLINE | ID: mdl-24579632

RESUMEN

Recently, realizations of Kitaev physics have been sought in the A2IrO3 family of honeycomb iridates, originating from oxygen-mediated exchange through edge-shared octahedra. However, for the jeff=1/2 Mott insulator in these materials, exchange from direct d-orbital overlap is relevant, and it was proposed that a Heisenberg term should be added to the Kitaev model. Here, we provide the generic nearest-neighbor spin Hamiltonian when both oxygen-mediated and direct overlap are present, containing a bond-dependent off-diagonal exchange in addition to Heisenberg and Kitaev terms. We analyze this complete model using a combination of classical techniques and exact diagonalization. Near the Kitaev limit, we find new magnetic phases, 120° and incommensurate spiral order, as well as extended regions of zigzag and stripy order. Possible applications to Na2IrO3 and Li2IrO3 are discussed.

11.
Phys Rev Lett ; 106(5): 056405, 2011 Feb 04.
Artículo en Inglés | MEDLINE | ID: mdl-21405417

RESUMEN

The EtMe(3)P and EtMe(3)Sb triangular organic salts are distinguished from other Pd[(dmit)(2)] based salts, as they display valence bond and no long-range order, respectively. Under pressure, a superconducting phase is revealed in EtMe(3)P near the boundary of valence bond order. We use slave-rotor theory with an enlarged unit cell to study competition between uniform and broken translational symmetry states, offering a theoretical framework capturing the superconducting, valence bond order, spin liquid, and metallic phases on an isotropic triangular lattice. Our finite temperature phase diagram manifests a remarkable resemblance to the phase diagram of the EtMe(3)P salt, where the reentrant transition of insulator-metal-insulator type can be explained by an entropy difference between the metal and U(1) spin liquid. We predict different temperature dependence of the specific heat between the spin liquid and metal.

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