4,115 research outputs found

    Breast Cancer Treatment Practices in Elderly Women in a Community Hospital

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    Background. Elderly women with breast cancer are considered underdiagnosed and undertreated, and this adversely affects their overall survival. Methods. A total of 393 female breast cancer patients aged 70 years and older, diagnosed within the years 1989–1999, were identified from the tumor registry of The Brooklyn Hospital Center. Comparisons between the 3 different subgroups 70–74, 75–79, and 80 years and older were made using the Pearson Chi Square test. Results. Lumpectomy was performed in 42% of all patients, while mastectomy was done in 46% of patients. Adjuvant therapy such as chemotherapy, radiation therapy, and hormonal therapy were done in 12%, 25%, and 38%, respectively. Forty-seven percent of patients with positive lymph nodes received chemotherapy. Eighty-six percent of patients who were estrogen receptor-positive received adjuvant hormonal therapy. Overall five-year survival was only 14% for the ≥80 age group, compared to that of 32% and 35% for the 70–74 and the 75–79 age groups, respectively. Conclusions. Surgery was performed in majority of these patients, about half received lumpectomy, the other half mastectomy. Adjuvant therapies were frequently excluded, with only hormonal therapy being the most commonly used. Overall five-year survival is significantly worse in patients ≥80 years with breast cancer

    On quantum coding for ensembles of mixed states

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    We consider the problem of optimal asymptotically faithful compression for ensembles of mixed quantum states. Although the optimal rate is unknown, we prove upper and lower bounds and describe a series of illustrative examples of compression of mixed states. We also discuss a classical analogue of the problem.Comment: 23 pages, LaTe

    Research of non-specific hyperreactivity of upper airways in subjects with gastro-esophageal reflux (G.E.R.): Preliminary reports

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    An association between asthma and gastro-esophageal reflux (GER) is well recognized but the underlying mechanism is still unclear. The authors suggest that could exist an association between GER and upper airways hyperreactivity and this association could represents the mechanism underlying the lower esophageal sphincter releasing, that determine the reflux. In fact they suppose that, the noxious injury of acid reflux follows a course that could be: pharynx → larynx → bronchi → 1/3 inferior of the esophagus → reflux. From these presuppositions the authors carried out a study on the possible relationship between GER and non-specific hyperreactivity of upper airways on 14 subjects, divided in 2 groups: 10 subjects with functional GER, 4 subjects suffering from GER caused by hiatus hernia as control group. All patients had a thorough medical history, ENT examination with rigid and flexible endoscope, anterior Rhinomanometry (RRM), skin-test for inhalant and alimentary allergens, RAST, audiometric exam, non-specific nasal provocation test (NSNPT) with histamine, using as control the number of sneezes. From a through analysis of objective examination and from the results of the NSNPT with histamine resulted that all subjects with functional GER were rhinopathics. In all tests both in vivo (Skin-test) and in vitro (RAST) for the most common allergens (pollens-inhalant-mycophites-alimentary) the results were negative. The authors also found an involvement of paranasal sinuses that raised: 91% in the patients with recurrents phlogosis due to non specific nasal hyperreactivity; 40.9% in the allergic subjects (20% in the Graminacee +; 32% in the Parietaria O. +; 76% in the Dermatophagoides Pt. +; others 4%); 100% in the ASA-intollerance subjects. The NSNSPT with histamine showed in the group with functional GER a hyperreactivity with sneezes in 6/10 subjects, and 1/4 subjects of the group with GER with hiatus hernia. The RRM variations showed an unilateral nasal hyperreactivity in 6/10, bilateral in 3/10 subjects of the group with functional GER. In the group with GER with hiatus hernia only 1/4 subject showed reliable unilateral RRM variation. From the analysis of data resulted that subjects with functional GER showed a completely involvement of the upper airways and not only of the pharynx and larynx, caused by non specific hyperreactivity at the NSNPT with histamine, associated with a chronic pathology

    Reaction Time of a Group of Physics Students

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    The reaction time of a group of students majoring in Physics is reported here. Strong co-relation between fatigue, reaction time and performance have been seen and may be useful for academicians and administrators responsible of working out time-tables, course structures, students counsellings etc.Comment: 10 pages, 4 figure

    Clustering and the hyperbolic geometry of complex networks

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    Clustering is a fundamental property of complex networks and it is the mathematical expression of a ubiquitous phenomenon that arises in various types of self-organized networks such as biological networks, computer networks or social networks. In this paper, we consider what is called the global clustering coefficient of random graphs on the hyperbolic plane. This model of random graphs was proposed recently by Krioukov et al. as a mathematical model of complex networks, under the fundamental assumption that hyperbolic geometry underlies the structure of these networks. We give a rigorous analysis of clustering and characterize the global clustering coefficient in terms of the parameters of the model. We show how the global clustering coefficient can be tuned by these parameters and we give an explicit formula for this function.Comment: 51 pages, 1 figur

    Comparison of 35 and 50 {\mu}m thin HPK UFSD after neutron irradiation up to 6*10^15 neq/cm^2

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    We report results from the testing of 35 {\mu}m thick Ultra-Fast Silicon Detectors (UFSD produced by Hamamatsu Photonics (HPK), Japan and the comparison of these new results to data reported before on 50 {\mu}m thick UFSD produced by HPK. The 35 {\mu}m thick sensors were irradiated with neutrons to fluences of 0, 1*10^14, 1*10^15, 3*10^15, 6*10^15 neq/cm^2. The sensors were tested pre-irradiation and post-irradiation with minimum ionizing particles (MIPs) from a 90Sr \b{eta}-source. The leakage current, capacitance, internal gain and the timing resolution were measured as a function of bias voltage at -20C and -27C. The timing resolution was extracted from the time difference with a second calibrated UFSD in coincidence, using the constant fraction method for both. Within the fluence range measured, the advantage of the 35 {\mu}m thick UFSD in timing accuracy, bias voltage and power can be established.Comment: 9 pages, 9 figures, HSTD11 Okinawa. arXiv admin note: text overlap with arXiv:1707.0496

    Playing Ping Pong with Light: Directional Emission of White Light

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    Over the last decades, light-emitting diodes (LED) have replaced common light bulbs in almost every application, from flashlights in smartphones to automotive headlights. Illuminating nightly streets requires LEDs to emit a light spectrum that is perceived as pure white by the human eye. The power associated with such a white light spectrum is not only distributed over the contributing wavelengths but also over the angles of vision. For many applications, the usable light rays are required to exit the LED in forward direction, namely under small angles to the perpendicular. In this work, we demonstrate that a specifically designed multi-layer thin film on top of a white LED increases the power of pure white light emitted in forward direction. Therefore, the deduced multi-objective optimization problem is reformulated via a real-valued physics-guided objective function that represents the hierarchical structure of our engineering problem. Variants of Bayesian optimization are employed to maximize this non-deterministic objective function based on ray tracing simulations. Eventually, the investigation of optical properties of suitable multi-layer thin films allowed to identify the mechanism behind the increased directionality of white light: angle and wavelength selective filtering causes the multi-layer thin film to play ping pong with rays of light

    Response theory for time-resolved second-harmonic generation and two-photon photoemission

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    A unified response theory for the time-resolved nonlinear light generation and two-photon photoemission (2PPE) from metal surfaces is presented. The theory allows to describe the dependence of the nonlinear optical response and the photoelectron yield, respectively, on the time dependence of the exciting light field. Quantum-mechanical interference effects affect the results significantly. Contributions to 2PPE due to the optical nonlinearity of the surface region are derived and shown to be relevant close to a plasmon resonance. The interplay between pulse shape, relaxation times of excited electrons, and band structure is analyzed directly in the time domain. While our theory works for arbitrary pulse shapes, we mainly focus on the case of two pulses of the same mean frequency. Difficulties in extracting relaxation rates from pump-probe experiments are discussed, for example due to the effect of detuning of intermediate states on the interference. The theory also allows to determine the range of validity of the optical Bloch equations and of semiclassical rate equations, respectively. Finally, we discuss how collective plasma excitations affect the nonlinear optical response and 2PPE.Comment: 27 pages, including 11 figures, version as publishe

    Assortment optimisation under a general discrete choice model: A tight analysis of revenue-ordered assortments

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    The assortment problem in revenue management is the problem of deciding which subset of products to offer to consumers in order to maximise revenue. A simple and natural strategy is to select the best assortment out of all those that are constructed by fixing a threshold revenue π\pi and then choosing all products with revenue at least π\pi. This is known as the revenue-ordered assortments strategy. In this paper we study the approximation guarantees provided by revenue-ordered assortments when customers are rational in the following sense: the probability of selecting a specific product from the set being offered cannot increase if the set is enlarged. This rationality assumption, known as regularity, is satisfied by almost all discrete choice models considered in the revenue management and choice theory literature, and in particular by random utility models. The bounds we obtain are tight and improve on recent results in that direction, such as for the Mixed Multinomial Logit model by Rusmevichientong et al. (2014). An appealing feature of our analysis is its simplicity, as it relies only on the regularity condition. We also draw a connection between assortment optimisation and two pricing problems called unit demand envy-free pricing and Stackelberg minimum spanning tree: These problems can be restated as assortment problems under discrete choice models satisfying the regularity condition, and moreover revenue-ordered assortments correspond then to the well-studied uniform pricing heuristic. When specialised to that setting, the general bounds we establish for revenue-ordered assortments match and unify the best known results on uniform pricing.Comment: Minor changes following referees' comment
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