909 research outputs found

    Multiplicity results for periodic solutions of second order ODEs with asymmetric nonlinearities

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    Abstract. We prove various results on the existence and multiplicity of harmonic and subharmonic solutions to the second order nonautonomous equation x ′ ′ + g(x) =s+w(t, x), as s → + ∞ or s →−∞,where g is a smooth function defined on a open interval]a, b[ ⊂ R. The hypotheses we assume on the nonlinearity g(x) allow us to cover the case b =+∞(or a = −∞) andghaving superlinear growth at infinity, as well as the case b<+∞(or a>−∞) and ghaving a singularity in b (respectively in a). Applications are given also to situations like g ′ (−∞) = g ′ (+∞) (including the so-called “jumping nonlinearities”). Our results are connected to the periodic Ambrosetti- Prodi problem and related problems arising from the Lazer- McKenna suspension bridges model. 1

    Flavour Changing Higgs Couplings in a Class of Two Higgs Doublet Models

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    We analyse various flavour changing processes like thu,hct\to hu,hc, hτe,τμh\to \tau e,\tau\mu as well as hadronic decays hbs,bdh\to bs,bd, in the framework of a class of two Higgs doublet models where there are flavour changing neutral scalar currents at tree level. These models have the remarkable feature of having these flavour-violating couplings entirely determined by the CKM and PMNS matrices as well as tanβ\tan\beta. The flavour structure of these scalar currents results from a symmetry of the Lagrangian and therefore it is natural and stable under the renormalization group. We show that in some of the models the rates of the above flavour changing processes can reach the discovery level at the LHC at 13 TeV even taking into account the stringent bounds on low energy processes, in particular μeγ\mu\to e\gamma.Comment: 33 pages, 8 figures; matches version accepted for publicatio

    What if the Masses of the First Two Quark Families are not Generated by the Standard Higgs?

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    We point out that, in the context of the SM, V132+V232|V^2_{13}| + | V^2_{23}| is expected to be large, of order one. The fact that V132+V2321.6×103|V^2_{13}| + |V^2_{23}| \approx 1.6 \times 10^{-3} motivates the introduction of a symmetry S which leads to VCKM=1 ⁣ ⁣ ⁣IV_{CKM} ={1\>\!\!\!\mathrm{I}} , with only the third generation of quarks acquiring mass. We consider two scenarios for generating the mass of the first two quark generations and full quark mixing. One consists of the introduction of a second Higgs doublet which is neutral under S. The second scenario consists of assuming New Physics at a high energy scale , contributing to the masses of light quark generations, in an effective field theory approach. This last scenario leads to couplings of the Higgs particle to sss\overline s and ccc \overline c which are significantly enhanced with respect to those of the SM. In both schemes, one has scalar-mediated flavour- changing neutral currents which are naturally suppressed. Flavour violating top decays are predicted in the second scenario at the level \mbox{Br} (t \rightarrow h c ) \geq 5\times 10^{-5}.Comment: 11 pages, 1 figur

    Does customer-based reputation add to social and mass media reputation in judging social responsibility of banks?

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    Purpose: Reputation is a critical asset for finance and banking organizations where the mere suspicion of a problem suffices to trigger media turmoil with high risk of market share losses. Investing in media to build reputation has been therefore a priority for banks. However, another source of reputation may stem from direct front-office contact and it is yet unknown to which extent it plays a role when confronted with the widespread social and mass media reach. This study aims at testing the extent of the importance of customer-based reputation, as against media-based reputation, in explaining customer outcomes.info:eu-repo/semantics/publishedVersio

    Dynamical behaviour of epidemiological models with sub-optimal immunity and nonlinear incidence

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    In this paper we analyze the dynamics of two families of epidemiological models which correspond to transitions from the SIR (susceptible-infectious-resistant) to the SIS (susceptible-infectious-susceptible) frameworks. In these models we assume that the force of infection is a nonlinear function of density of infectious individuals, I. Conditions for the existence of backwards bifurcations, oscillations and Bogdanov-Takens points are give

    ACTH-dependent Cushing's syndrome: a revision of 43 cases

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    AIM: To evaluate the characteristics and outcomes of the patients diagnosed as ACTH-dependent Cushing syndrome, registered in the department. MATERIAL AND METHODS: We reviewed the files of forty-three patients followed from 1974 to 2002. RESULTS: A progressive rise in the number of patients diagnosed was found, being 80% females. Clinical suspicion was based mostly on the typical fat distribution; hirsutism and amenorrhoea were important in women. The more reliable diagnostic tests were: 11 pm cortisol, day curve of ACTH and cortisol, and dexamethasone suppression tests. The ACTH response to CRH during inferior petrosal sinus sampling permitted the diagnosis of ectopic source. In thirty-seven patients a pituitary adenoma was diagnosed. The three patients diagnosed before 1985 went for bilateral adrenalectomy (Nelson's syndrome in two); the others were submitted to transsphenoidal pituitary adenomectomy, obtaining remission in twenty six at the first operation and in two others at the second. Three patients had a recidive. Of the six patients with persistent disease (all treated with metyrapone or ketoconazole), three were submitted to radiotherapy, two to bilateral adrenalectomy, and one was waiting for surgery. Four patients had a bronchial carcinoid, successfully removed in three. One patient was lost to follow-up and another was still being evaluated. CONCLUSIONS: We found a positive evolution in the capacity to diagnose and treat these patients. Neurosurgical ability to achieve remission was 80% in the operated cases. More effective technical methods and drugs, as well as a multidisciplinary and dedicated medical team, lead to long lasting remissions in most of the patients

    Oriented Tailoring of Plastic Antibodies for Prostate Specific Antigen and Application of the Imprinted Material as Ionophore in Potentiometric Detection

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    Poster, presented at Nanobio Europe, Varese, Italy, 18 - 20 June, 2012.Prostate Specific Antigen (PSA) is the biomarker of choice for screening prostate cancer throughout the population, with PSA values above 10 ng/mL pointing out a high probability of associated cancer1. According to the most recent World Health Organization (WHO) data, prostate cancer is the commonest form of cancer in men in Europe2. Early detection of prostate cancer is thus very important and is currently made by screening PSA in men over 45 years old, combined with other alterations in serum and urine parameters. PSA is a glycoprotein with a molecular mass of approximately 32 kDa consisting of one polypeptide chain, which is produced by the secretory epithelium of human prostate. Currently, the standard methods available for PSA screening are immunoassays like Enzyme-Linked Immunoabsorbent Assay (ELISA). These methods are highly sensitive and specific for the detection of PSA, but they require expensive laboratory facilities and high qualify personal resources. Other highly sensitive and specific methods for the detection of PSA have also become available and are in its majority immunobiosensors1,3-5, relying on antibodies. Less expensive methods producing quicker responses are thus needed, which may be achieved by synthesizing artificial antibodies by means of molecular imprinting techniques. These should also be coupled to simple and low cost devices, such as those of the potentiometric kind, one approach that has been proven successful6. Potentiometric sensors offer the advantage of selectivity and portability for use in point-of-care and have been widely recognized as potential analytical tools in this field. The inherent method is simple, precise, accurate and inexpensive regarding reagent consumption and equipment involved. Thus, this work proposes a new plastic antibody for PSA, designed over the surface of graphene layers extracted from graphite. Charged monomers were used to enable an oriented tailoring of the PSA rebinding sites. Uncharged monomers were used as control. These materials were used as ionophores in conventional solid-contact graphite electrodes. The obtained results showed that the imprinted materials displayed a selective response to PSA. The electrodes with charged monomers showed a more stable and sensitive response, with an average slope of -44.2 mV/decade and a detection limit of 5.8X10-11 mol/L (2 ng/mL). The corresponding non-imprinted sensors showed smaller sensitivity, with average slopes of -24.8 mV/decade. The best sensors were successfully applied to the analysis of serum samples, with percentage recoveries of 106.5% and relatives errors of 6.5%

    Melanin nanoparticles as a promising tool for biomedical applications – a review

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    Melanin is a biopolymer of easy and cheap availability that can be found among the living organisms and excels for its biocompatibility and biodegradability properties, along with scavenging abilities, metal chelation and electronic conductance. This biomaterial can act as a nanocarrier or agent itself to be used in diverse biomedical applications, such as imaging, controlled drug release, bioengineering and bioelectronics, antioxidant applications and theranostics. In this review, the melanin source and structure, its physicochemical properties, melanin-like polymers as well as the differences among those will be elucidated. The focus will be the discussion of the current approaches that apply melanin nanoparticles (MNPs) and melanin-like nanoparticles (MLNPs) in the biomedical field, to which promising capabilities have been attributed, regarding optoelectronic, photoconductivity and photoacoustic. The use of these nanoparticles, in the last 10 years, in topics as drug delivery or theranostics will be detailed and the major achievements will be discussed. Overall, we anticipate that melanin can drive us toward a new paradigm in medical diagnostics and treatments, since applying melanin features possibly its use as a theranostics nanocarrier agent, not only for diagnostics, but also for photothermal therapy and controlled drug release through chemotherapy.VM Correlo would like to acknowledge FROnTHERA (NORTE-01–0145-FEDER-0000232) project. RRebelo would like to acknowledge BREAST-IT PTDC/BTM-ORG/28168/2017 project
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