1,787 research outputs found

    Deterministic versus Probabilistic Methods for Searching for an Evasive Target

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    Several advanced applications of autonomous aerial vehicles in civilian and military contexts involve a searching agent with imperfect sensors that seeks to locate a mobile target in a given region. Effectively managing uncertainty is key to solving the related search problem, which is why all methods devised so far hinge on a probabilistic formulation of the problem and solve it through branch-and-bound algorithms, Bayesian filtering or POMDP solvers. In this paper, we consider a class of hard search tasks involving a target that exhibits an intentional evasive behaviour and moves over a large geographical area, i.e., a target that is particularly difficult to track down and uncertain to locate. We show that, even for such a complex problem, it is advantageous to compile its probabilistic structure into a deterministic model and use standard deterministic solvers to find solutions. In particular, we formulate the search problem for our uncooperative target both as a deterministic automated planning task and as a constraint programming task and show that in both cases our solution outperforms POMDPs methods

    Alteration of colonic excitatory tachykininergic motility and enteric inflammation following dopaminergic nigrostriatal neurodegeneration

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    Background: Parkinson's disease (PD) is frequently associated with gastrointestinal (GI) symptoms, including constipation and defecatory dysfunctions. The mechanisms underlying such disorders are still largely unknown, although the occurrence of a bowel inflammatory condition has been hypothesized. This study examined the impact of central dopaminergic degeneration, induced by intranigral injection of 6-hydroxydopamine (6-OHDA), on distal colonic excitatory tachykininergic motility in rats. Methods: Animals were euthanized 4 and 8 weeks after 6-OHDA injection. Tachykininergic contractions, elicited by electrical stimulation or exogenous substance P (SP), were recorded in vitro from longitudinal muscle colonic preparations. SP, tachykininergic NK1 receptor, and glial fibrillary acidic protein (GFAP) expression, as well as the density of eosinophils and mast cells in the colonic wall, were examined by immunohistochemical analysis. Malondialdehyde (MDA, colorimetric assay), TNF, and IL-1 beta (ELISA assay) levels were also examined. The polarization of peritoneal macrophages was evaluated by real-time PCR. Results: In colonic preparations, electrically and SP-evoked tachykininergic contractions were increased in 6-OHDA rats. Immunohistochemistry displayed an increase in SP and GFAP levels in the myenteric plexus, as well as NK1 receptor expression in the colonic muscle layer of 6-OHDA rats. MDA, TNF, and IL-1 beta levels were increased also in colonic tissues from 6-OHDA rats. In 6-OHDA rats, the number of eosinophils and mast cells was increased as compared with control animals, and peritoneal macrophages polarized towards a pro-inflammatory phenotype. Conclusions: The results indicate that the induction of central nigrostriatal dopaminergic degeneration is followed by bowel inflammation associated with increased oxidative stress, increase in pro-inflammatory cytokine levels, activation of enteric glia and inflammatory cells, and enhancement of colonic excitatory tachykininergic motility

    Mass concentration for Ergodic Choquard Mean-Field Games

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    We study concentration phenomena in the vanishing viscosity limit for second-order stationary Mean-Field Games systems defined in the whole space RN\mathbb{R}^N with Riesz-type aggregating nonlocal coupling and external confining potential. In this setting, every player of the game is attracted toward congested areas and the external potential discourages agents to be far away from the origin. Focusing on the mass-subcritical regime Nγ<α<NN-\gamma'<\alpha<N, we study the behavior of solutions in the vanishing viscosity limit, namely when the diffusion becomes negligible. First, we investigate the asymptotic behavior of rescaled solutions as ε0\varepsilon\to0, obtaining existence of classical solutions to potential free MFG systems with Riesz-type coupling. Secondly, we prove concentration of mass around minima of the potential.Comment: accepted in ESAIM: COC

    Existence and compactness of conformal metrics on the plane with unbounded and sign-changing Gaussian curvature

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    We show that the prescribed Gaussian curvature equation in R2\mathbb{R}^2 Δu=(1xp)e2u,-\Delta u= (1-|x|^p) e^{2u}, has solutions with prescribed total curvature equal to Λ:=R2(1xp)e2udxR\Lambda:=\int_{\mathbb{R}^2}(1-|x|^p)e^{2u}dx\in \mathbb{R}, if and only if p(0,2)and(2+p)πΛ<4πp\in(0,2) \qquad \text{and} \qquad (2+p)\pi\le\Lambda<4\pi and prove that such solutions remain compact as ΛΛˉ[(2+p)π,4π)\Lambda\to\bar{\Lambda}\in[(2+p)\pi,4\pi), while they produce a spherical blow-up as Λ4π\Lambda\uparrow4\pi

    La valutazione della genitorialità. una ricerca esplorativa, per capire come venga vissuta da un gruppo di cittadini romani

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    This paper reports the data of an exploratory research conducted with a group of Roman citizens who were asked what they thought about the possibility of assessing the parenting of families considered at risk over the parental expertise. Citizens were interviewed and the interviews were submitted to AET, Emotional Analysis of the Text. Assessing parenting often involves families with internal conflicts. We think the conflict is not only there. Conflicts also cross the theoretical, legal, and political hypotheses, which base the opportunity to intervene within the issues involved in parental evaluation. They are also found in the relationship between families and services. Legal and sociological literature advise the presence of these conflicts and discuss the issues; whereas the psychological and psychiatric one is focused on the application of techniques, whether they are evaluation, psychotherapy, re-education. This perspective does not consider the conflicting complexity which founds the parental evaluation, but it is focused only on the family. We were interested in analysing, in this context, what is the citizens’ perception of the evaluation of parenting, who are their potential customers and users; in particular, if and how these conflictual dynamics are perceived by them. After the analysis of the interview, the data outline three cultures. One proposes the traditional Italian family, the feminised family and designated to the care of members in difficulty within the home wall; family today in a strong crisis within processes of change. Another proposes the centrality of the court and the legal culture, founded on evaluations and resolving actions that often can result in child custody actions. These two cultures contrast: when the traditional family is missing, the court appears. There is no counseling which concerns the changes of the family. Psychological and neuropsychiatric counseling agencies do not appear in the data, except for social services, in any case subordinated to the court. A third culture proposes an “ideal” adult, who with balance and reflection skills, has to face a fearful context, but it is an isolated individual, without a relational context of reference. This culture seems to opposite the dissolution of relational contexts – state, organizations, family – to the idealized individual, self-determined and alone. The development of psychological function in the assessment of parenting concerns two aspects: the importance of studying the complexity of the social mandate and the intervention with the conflicting relationships of the family and of all the other actors involved

    Fibrotic and Vascular Remodelling of Colonic Wall in Patients with Active Ulcerative Colitis

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    open16noIntestinal fibrosis is a complication of inflammatory bowel disease [IBD]. Although fibrostenosis is a rare event in ulcerative colitis [UC], there is evidence that a fibrotic rearrangement of the colon occurs in the later stages. This is a retrospective study aimed at examining the histopathological features of the colonic wall in both short-lasting [SL] and long-lasting [LL] UC. Surgical samples of left colon from non-stenotic SL [a parts per thousand currency sign 3 years, n = 9] and LL [a parts per thousand yen 10 years, n = 10] UC patients with active disease were compared with control colonic tissues from cancer patients without UC [n = 12] to assess: collagen and elastic fibres by histochemistry; vascular networks [CD31/CD105/nestin] by immunofluorescence; parameters of fibrosis [types I and III collagen, fibronectin, RhoA, alpha-smooth muscle actin [alpha-SMA], desmin, vimentin], and proliferation [proliferating nuclear antigen [PCNA]] by western blot and/or immunolabelling. Colonic tissue from both SL-UC and LL-UC showed tunica muscularis thickening and transmural activated neovessels [displaying both proliferating CD105-positive endothelial cells and activated nestin-positive pericytes], as compared with controls. In LL-UC, the increased collagen deposition was associated with an up-regulation of tissue fibrotic markers [collagen I and III, fibronectin, vimentin, RhoA], an enhancement of proliferation [PCNA] and, along with a loss of elastic fibres, a rearrangement of the tunica muscularis towards a fibrotic phenotype. A significant transmural fibrotic thickening occurs in colonic tissue from LL-UC, together with a cellular fibrotic switch in the tunica muscularis. A full-thickness angiogenesis is also evident in both SL- and LL-UC with active disease, as compared with controls.openIppolito, Chiara; Colucci, Rocchina; Segnani, Cristina; Errede, Mariella; Girolamo, Francesco; Virgintino, Daniela; Dolfi, Amelio; Tirotta, Erika; Buccianti, Piero; Di Candio, Giulio; Campani, Daniela; Castagna, Maura; Bassotti, Gabrio; Villanacci, Vincenzo; Blandizzi, Corrado; Bernardini, NunziaIppolito, Chiara; Colucci, ROCCHINA LUCIA; Segnani, Cristina; Errede, Mariella; Girolamo, Francesco; Virgintino, Daniela; Dolfi, Amelio; Tirotta, Erika; Buccianti, Piero; Di Candio, Giulio; Campani, Daniela; Castagna, Maura; Bassotti, Gabrio; Villanacci, Vincenzo; Blandizzi, Corrado; Bernardini, Nunzi

    Enteric dysfunctions in experimental Parkinson's disease: alterations of excitatory cholinergic neurotransmission regulating colonic motility in rats

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    Parkinson's disease (PD) is frequently associated with gastrointestinal symptoms, mostly represented by constipation and defecatory dysfunctions. This study examined the impact of central dopaminergic denervation, induced by injection of 6-hydroxydopamine (6-OHDA) into the medial forebrain bundle, on distal colonic excitatory cholinergic neuromotor activity in rats. Animals were euthanized 4 and 8 weeks after 6-OHDA injection. In vivo colonic transit was evaluated by radiological assay. Electrically and carbachol-induced cholinergic contractions were recorded in vitro from longitudinal and circular muscle colonic preparations, while acetylcholine levels were assayed in their incubation media. Choline acetyltransferase (ChAT), HuC/D (pan-neuronal marker), muscarinic M2 and M3 receptors. As compared with control rats, at week 4 6-OHDA-treated animals displayed the following changes: decreased in vivo colonic transit rate; impaired electrically evoked neurogenic cholinergic contractions; enhanced carbachol-induced contractions; decreased basal and electrically stimulated acetylcholine release from colonic tissues; decreased ChAT immunopositivity in the neuromuscular layer; unchanged density of HuC/D immunoreactive myenteric neurons; increased expression of colonic muscarinic M2 and M3 receptors. The majority of such alterations were detected also at week 8 post-6-OHDA injection. These findings indicate that central nigrostriatal dopaminergic denervation is associated with an impaired excitatory neurotransmission characterized by a loss of myenteric neuronal ChAT positivity and decrease in acetylcholine release, resulting in a dysregulated smooth muscle motor activity, which likely contributes to the concomitant decrease in colonic transit rate

    Un risultato di h-principle per curve a curvatura costante in R^n

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    Oggetto di questa tesi è mostrare che ogni curva liscia immersa nello spazio euclideo n-dimensionale, può essere deformata in una curva con curvatura costante, mediante una perturbazione arbitrariamente piccola della curva iniziale e delle sue rette tangenti. Tale valore costante della curvatura deve essere maggiore o uguale del massimo della curvatura della curva iniziale, e si dimostra che tale limite inferiore è ottimale. Questo significa che le curve lisce di curvatura costante, soddisfano, secondo la terminologia di Gromov, il `relative C^1-dense h-principle' nello spazio delle curve immerse in R^n
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