117 research outputs found

    Existence of H-bubbles in a perturbative setting

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    Given a C^1 function H: R^3 → R, we look for H-bubbles, i.e., surfaces in R^3 parametrized by the sphere S^2 with mean curvature H at every regular point. Here we study the case H(u)=H_0(u)+∈H_1(u) where H_0 is some "good" curvature (for which there exist H_ 0-bubbles with minimal energy, uniformly bounded in L^∞), ∈ is the smallness parameter, and H_1 is any C^1 functio

    Multiple homoclinic solutions for a class of autonomous singular systems in R2\bold R^2R2.

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    We look for homoclinic solutions for a class of second order autonomous Hamiltonian systems in R-2 with a potential V having a strict global maximum at the origin and a finite set S subset of R-2 of singularities, namely V(x) --> -infinity as dist(x,S) --> 0. We prove that if V satisfies a suitable geometrical property then for any k epsilon N the system admits a homoclinic orbit turning k times around a singularity xi epsilon S

    On the existence of homoclinic orbits for the asymptotically periodic Duffing Equation

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    Using variational methods, we show the existence of a homoclinic orbit for the Duffing equation ddotu+u=a(t)up1u-ddot u+u=a(t)|u|^{p-1}u, where p>1p>1 and ainLinfty(R)ain L^infty(R) is a positive function of the form a=a0+ainftya=a_0+a_infty with ainftya_infty periodic, and a0(t)o0a_0(t) o 0 as topminftyt opminfty satisfying suitable conditions. Under the same assumptions on aa, we also prove that the perturbed equation ddotu+u=a(t)up1u+alpha(t)g(u)-ddot u+u=a(t)|u|^{p-1}u+alpha(t)g(u) admits a homoclinic orbit whenever ginC1(R)gin C^1(R) satisfies g(u)=O(u)g(u)=O(u) as uo0u o 0 and alphainLinfty(R)alphain L^infty(R), alpha(t)o0alpha(t) o 0 as topminftyt opminfty and alphaLinfty|alpha|_{L^infty} is sufficiently small

    Play-based activities with CoderBot in a pediatric ward: A case study

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    Being hospitalized is a threatening and stressful experience for many children. From a psychological point of view, children may experience increased feelings of anxiety and fear that can negatively influence their behavioral, cognitive, and emotional outcomes. To mitigate such adverse effects on children’s mental health and well-being, interventions that might contribute to protecting the emotional domain of hospitalized children are welcome. The present case study of a single-setting intervention allowed us to evaluate the impact, on children admitted to a pediatric short-term recovery ward (N = 61), of participating in play-based activities with a CoderBot robot. The methodology spanned multiple data sources (children, parents, nurses), field observation, and a sequential (quantitative–qualitative) mixed-method approach to data analysis. We found that robot-based activities are associated with enhanced well-being (particularly positive emotions). Both the participating children and their caregivers reported that the activity was enjoyable and interesting, especially thanks to its technologically innovative nature. We critically discuss these positive findings in relation to the strengths of our pilot study, as well as its contextual and methodological limitations, and outline possible future lines of development for this kind of project

    Genericity of the existence of infinitely many solutions for a class of semilinear elliptic equations in Rn

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    We show, by variational methods, that there exists a set A open and dense in {a ∈ L∞(RN) : liminf|x|→∞ a(x) ≥ 0} such that if a ∈ A then the problem −∆u + u = a(x)|u| p−1u, u ∈ H1(RN), with p subcritical (or more general nonlinearities), admits infinitely many solutions.ou

    On the existence of infinitely many solutions for a class of semilinear elliptic equations in R^N

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    We show, by variational methods, that there exists a set AA open and dense in ainLinfty(RN) : ageq0{ ain L^infty(R^N)~:~ ageq 0} such that if ainAain A then the problem Deltau+u=a(x)up1u -Delta u+u=a(x)|u|^{p-1}u, uinH1(RN)uin H^1(R^N), with pp subcritical (or more general nonlinearities), admits infinitely many solutions

    Neurodevelopmental versus neurodegenerative model of schizophrenia and bipolar disorder : comparison with physiological brain development and aging

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    Available data support a contribution of both neurodevelopmental and neurodegenerative factors in the etiology of schizophrenia (SCH) and bipolar disorder (BD). Of note, one of the most important issue of the current psychiatric research is to identify the specific factors that contribute to impaired brain development and neurodegeneration in SCH and BD, and especially how these factors alter normal brain development and physiological aging process. Our hypothesis is that only specific damages, taking place in precise brain development stages, are associated with future SCH /BD onset and that neurodegeneration consists of an acceleration of brain aging after SCH /BD onset. In support of our hypothesis, the results of the present narrative mini-review shows as neurodevelopmental damages generally contribute to neuropsychiatric syndromes (e.g. hypothyroidism or treponema pallidum), but only some of them are specifically associated with adult SCH and BD (e.g. toxoplasma or substance abuse), particularly if they happen in specific stages of brain development. On the other hand, cognitive impairment and brain changes, associated with long duration of SCH /BD, look like what happens during aging: memory, executive domains and prefrontal cortex are implicated both in aging and in SCH /BD progression. Future research will explore possible validity of this etiological model for SCH and BD

    600 MHz H-1 and C-13 NMR full assignments of two saponins from Nothapodytes foetida

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    The application of one- and two-dimensional nuclear magnetic resonance techniques to the structure elucidation of two saponins from Nothapodytes foetida is reported, Detailed structural information about the sapogenin, protobassic acid, and the oligosaccharidic chains, including sugar sequence and position of glycosidation, is provided
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