324 research outputs found

    Fertility traits of purebred Holsteins and 2- and 3-breed crossbred heifers and cows obtained from Swedish Red, Montbéliarde, and Brown Swiss sires.

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    The objective of this study was to compare fertility traits of heifers and primiparous cows from Swedish Red × Holstein (SR × HO; n = 634 and 581, respectively), Montbeliarde × Holstein (MO × HO; n = 126 and 114, respectively), Brown Swiss × Holstein (BS × HO; n = 59 and 50, respectively), and MO × (SR × HO) (n = 241 and 139, respectively) crossbreds, versus those of Holstein heifers and cows (HO; n = 3,483 and 2,549, respectively). Animals were born between 2007 and 2011, and belonged to 4 herds located in northern Italy. Heifers were compared for age at first service (AFS), age at first conception (AFC), interval between first service and conception (IFC), nonreturn rate at 56 d after first service (NR56), conception rate at first service (CR), and number of inseminations required for conception (INS). The same traits were evaluated in primiparous cows, except that AFS and AFC were replaced with days at first service (DFS) and days open (DO). The AFS, AFC, IFC, DFS, and DO traits were continuous variables and were thus analyzed under a proportional hazards Cox model that properly accounted for censoring among cows that were culled or failed to conceive. The NR56, CR, and INS traits were analyzed as binary traits using logistic regression. Our results indicated that, among heifers, SR × HO crossbreds had a better chance of having an earlier first service and conceiving earlier than HO, with hazard ratios (HR) of 1.31 for AFS and 1.34 for AFC. Similarly, MO × (SR × HO) crossbreds differed from HO heifers in this regard (HR = 1.18 and 1.24, respectively). For the primiparous cows, all crossbreds showed significant differences for DFS, DO, and IFC relative to purebred HO, with the exception of the BS × HO crossbreds. The MO × HO, SR × HO, and MO × (SR × HO) crossbred cows showed increased chances of having fewer DFS (HR = 1.40, 1.30, and 1.27, respectively), fewer DO (HR = 1.59, 1.43, and 1.58, respectively), and fewer IFC (HR = 1.52, 1.26, and 1.39, respectively) than HO cows. All crossbred genotypes, including BS × HO cows, showed higher probabilities for higher NR56, higher CR, and lower INS than purebred HO cows. Together, these findings indicate that the studied crossbred cows have higher reproductive potential than Holsteins

    Existence of conformal metrics with constant QQ-curvature

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    Given a compact four dimensional manifold, we prove existence of conformal metrics with constant QQ-curvature under generic assumptions. The problem amounts to solving a fourth-order nonlinear elliptic equation with variational structure. Since the corresponding Euler functional is in general unbounded from above and from below, we employ topological methods and minimax schemes, jointly with a compactness result by the second author.Comment: 36 pages, revised version. To appear in Annals of Mathematic

    Existence of solutions to a higher dimensional mean-field equation on manifolds

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    For m1m\geq 1 we prove an existence result for the equation (Δg)mu+λ=λe2muMe2mudμg(-\Delta_g)^m u+\lambda=\lambda\frac{e^{2mu}}{\int_M e^{2mu}d\mu_g} on a closed Riemannian manifold (M,g)(M,g) of dimension 2m2m for certain values of λ\lambda.Comment: 15 Page

    Time representation in reinforcement learning models of the basal ganglia

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    Reinforcement learning (RL) models have been influential in understanding many aspects of basal ganglia function, from reward prediction to action selection. Time plays an important role in these models, but there is still no theoretical consensus about what kind of time representation is used by the basal ganglia. We review several theoretical accounts and their supporting evidence. We then discuss the relationship between RL models and the timing mechanisms that have been attributed to the basal ganglia. We hypothesize that a single computational system may underlie both RL and interval timing—the perception of duration in the range of seconds to hours. This hypothesis, which extends earlier models by incorporating a time-sensitive action selection mechanism, may have important implications for understanding disorders like Parkinson's disease in which both decision making and timing are impaired

    An improved geometric inequality via vanishing moments, with applications to singular Liouville equations

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    We consider a class of singular Liouville equations on compact surfaces motivated by the study of Electroweak and Self-Dual Chern-Simons theories, the Gaussian curvature prescription with conical singularities and Onsager's description of turbulence. We analyse the problem of existence variationally, and show how the angular distribution of the conformal volume near the singularities may lead to improvements in the Moser-Trudinger inequality, and in turn to lower bounds on the Euler-Lagrange functional. We then discuss existence and non-existence results.Comment: some references adde

    La formazione degli insegnanti della classe 42/A – Informatica: l'esperienza dell'Università degli Studi di Milano

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    In Italia la formazione universitaria all'insegnamento nella scuola se- condaria ha una tradizione piuttosto recente: alle scuole di specializ- zazione attive negli anni 1999-2008 dovrebbero \u2013 secondo quanto pre- visto dal Decreto Ministeriale del 10 settembre 2010, n. 249 \u2013 sostituirsi lauree magistrali innestate sulla corrispondente formazione discipli- nare triennale; nel transitorio sono stati attivati corsi annuali riservati a laureati di secondo livello selezionati tramite esami (Tirocinio forma- tivo attivo, TFA) o titolari di un'esperienza professionale di insegna- mento di almeno 3 anni (Percorsi abilitanti speciali, PAS). Questo ca- pitolo descrive l'esperienza dell'Universit\ue0 degli Studi di Milano nel progettare e gestire i corsi 42/A TFA e PAS, nel triennio 2012-2015

    Genes deregulated in giant cell arteritis by Nanostring nCounter gene expression profiling in temporal artery biopsies

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    OBJECTIVE: To identify differentially expressed genes in temporal artery biopsies (TABs) from patients with giant cell arteritis (GCA) with different histological patterns of inflammation: transmural inflammation (TMI) and inflammation limited to adventitia (ILA), compared with normal TABs from patients without GCA. METHODS: Expression of 770 immune-related genes was profiled with the NanoString nCounter PanCancer Immune Profiling Panel on formalin-fixed paraffin-embedded TABs from 42 GCA patients with TMI, 7 GCA patients with ILA and 7 non-GCA controls. RESULTS: Unsupervised clustering of the samples revealed two distinct groups: normal TABs and TABs with ILA in one group, 41/42 TABs with TMI in the other one. TABs with TMI showed 31 downregulated and 256 upregulated genes compared with normal TABs; they displayed 26 downregulated and 187 upregulated genes compared with TABs with ILA (>2.0 fold changes and adjusted p values <0.05). Gene expression in TABs with ILA resembled normal TABs although 38 genes exhibited >2.0 fold changes, but these changes lost statistical significance after Benjamini-Yekutieli correction. Genes encoding TNF superfamily members, immune checkpoints, chemokine and chemokine receptors, toll-like receptors, complement molecules, Fc receptors for IgG antibodies, signalling lymphocytic activation molecules, JAK3, STAT1 and STAT4 resulted upregulated in TMI. CONCLUSIONS: TABs with TMI had a distinct transcriptome compared with normal TABs and TABs with ILA. The few genes potentially deregulated in ILA were also deregulated in TMI. Gene profiling allowed to deepen the knowledge of GCA pathogenesis
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