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Search Results: 1 - 10 of 191439 matches for " D. Cat Berro "
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Statistical analysis of inter-arrival times of rainfall events for Italian Sub-Alpine and Mediterranean areas
C. Agnese, G. Baiamonte, C. Cammalleri, D. Cat Berro, S. Ferraris,L. Mercalli
Advances in Science and Research (ASR) , 2012, DOI: 10.5194/asr-8-171-2012
Abstract: In this work a set of time-series of inter-arrival times of rainfall events, at daily scale, was analysed, with the aim to verify the issue of increasing duration of dry periods. The set consists of 12 time-series recorded at rain gauges in 1926–2005, six of them belong to an Italian Sub-Alpine area (Piedmont) and six to a Mediterranean one (Sicily). In order to overcome the problem related to limited sample size for high values of inter-arrival times, the discrete probability polylog-series distribution was used to fit the empirical data from partial (20 yr) time-series. Moreover, a simple qualitative trend analysis was applied to some high quantiles of inter-arrival times as well as to the average extent of rain clusters. The preliminary analysis seems to confirm the issue of increasing duration of dry periods for both environments, which is limited to the ''cold'' season.
Hot C-rich white dwarfs: testing the DB-DQ transition through pulsations
A. H. Córsico,A. D. Romero,L. G. Althaus,E. García-Berro
Physics , 2009, DOI: 10.1051/0004-6361/200912481
Abstract: Hot DQ white dwarfs constitute a new class of white dwarf stars, uncovered recently within the framework of the SDSS project. Recently, three hot DQ white dwarfs have been reported to exhibit photometric variability with periods compatible with pulsation g-modes. Here, we present a nonadiabatic pulsation analysis of the recently discovered carbon-rich hot DQ white dwarf stars. One of our main aims is to test the convective-mixing picture for the origin of hot DQs through the pulsational properties. Our study relies on the full evolutionary models of hot DQ white dwarfs recently developed by Althaus et al. (2009), that consistently cover the whole evolution from the born-again stage to the white dwarf cooling track. Specifically, we present a stability analysis of white dwarf models from stages before the blue edge of the DBV instability strip until the domain of the hot DQ white dwarfs, including the transition DB --> hot DQ white dwarf. We found that at evolutionary phases in which the models are characterized by He-dominated atmospheres, they exhibit unstable $g$-mode pulsations typical of DBV stars, and when the models become DQ white dwarfs with carbon-dominated atmospheres, they continue being pulsationally unstable with similar characteristics than DB models, and in agreement with the periods detected in variable hot DQ white dwarfs. Our calculations provide strong support to the convective-mixing picture for the formation of hot DQs. In particular, our results point to the existence of pulsating DB white dwarfs with very thin He-rich envelopes, which after passing the DBV instability strip become variable hot DQ stars. The existence of these DB stars with very thin envelopes could be investigated through asteroseismology.
The ages of very cool hydrogen-rich white dwarfs
M. Salaris,E. Garcia-Berro,M. Hernanz,J. Isern,D. Saumon
Physics , 2000, DOI: 10.1086/317235
Abstract: The evolution of white dwarfs is essentially a cooling process that depends primarily on the energy stored in their degenerate cores and on the transparency of their envelopes. In this paper we compute accurate cooling sequences for carbon-oxygen white dwarfs with hydrogen dominated atmospheres for the full range of masses of interest. For this purpose we use the most accurate available physical inputs for both the equation of state and opacities of the envelope and for the thermodynamic quantities of the degenerate core. We also investigate the role of the latent heat in the computed cooling sequences. We present separately cooling sequences in which the effects of phase separation of the carbon-oxygen binary mixture upon crystallization have been neglected, and the delay introduced in the cooling times when this mechanism is properly taken into account, in order to compare our results with other published cooling sequences which do not include a treatment of this phenomenon. We find that the cooling ages of very cool white dwarfs with pure hydrogen atmospheres have been systematically underestimated by roughly 1.5 Gyr at log(L/Lo)=-4.5 for an otherwise typical 0.6 Mo white dwarf, when phase separation is neglected. If phase separation of the binary mixture is included then the cooling ages are further increased by roughly 10%. Cooling tracks and cooling isochrones in several color-magnitude diagrams are presented as well.
An independent constraint on the secular rate of variation of the gravitational constant from pulsating white dwarfs
Alejandro H. Córsico,Leandro G. Althaus,Enrique García-Berro,Alejandra D. Romero
Physics , 2013, DOI: 10.1088/1475-7516/2013/06/032
Abstract: A secular variation of the gravitational constant modifies the structure and evolutionary time scales of white dwarfs. Using an state-of-the-art stellar evolutionary code and an up-to-date pulsational code we compute the effects of a secularly varying $G$ on the pulsational properties of variable white dwarfs. Comparing the the theoretical results obtained taking into account the effects of a running $G$ with the observed periods and measured rates of change of the periods of two well studied pulsating white dwarfs, G117--B15A and R548, we place constraints on the rate of variation of Newton's constant. We derive an upper bound $\dot G/G\sim -1.8\times 10^{-10}$ yr$^{-1}$ using the variable white dwarf G117--B15A, and $\dot G/G\sim -1.3\times 10^{-10}$ yr$^{-1}$ using R548. Although these upper limits are currently less restrictive than those obtained using other techniques, they can be improved in a future measuring the rate of change of the period of massive white dwarfs.
Efectos de la tensión y transfixión del cartílago de crecimiento con diferentes hilos de sutura: Estudio experimental en conejos
Díaz Gallardo,Paula; Catá,Ezequiel; Bagliardelli,Julio; Armando,Lucas; Allende,Christian;
Revista de la Asociaci?3n Argentina de Ortopedia y Traumatolog?-a , 2011,
Abstract: background: to determine changes in the distal femoral physis when surrounded or transfixed with different suture materials. methods: twenty-four distal femoral physes of 18 new zealand rabbits (7-8 weeks old) were divided into four groups of six rabbits each. in group 1 a prolene 3.0 suture was used. group 2 was divided in two, number 2a used a vicryl 3.0 suture, and number 2b a linen 60 suture; and in group 3 a vicryl 4.0 suture was used. the suture in groups 1, 2a and 2b transfixed the physis surrounding the lateral femoral condyle. in group 3 the physis was surrounded, not transfixed. results: imaging: in all cases the limb was shorter, group 3 was the most affected (average, 9.75 mm.). there were 9 cases of medial patellar dislocation (4 in group 2, 2 in group 1 and 2 in group 3). five cases of varus deformity were found (1 in group 1, 2 in group 3 and 2 in group 2). pathological anatomy results: the five layers of the physis were adequately preserved in all cases. no inflammatory response or foreign body-type giant cells, or epiphyseal fusions were found. connective tissue around the suture was found only in group 2b. conclusions: damage to the physis was mainly caused by the amount of pressure exerted on it regardless of the suture material used in each case because the pathological anatomy results did not reveal any abnormalities, and radiologically, a greater femoral varus and shortening was found in group 3 in which the pressure on the physis was greater in all its diameter without transfixing the physis. in groups 1, 2a and 2b the pressure was exerted around the lateral femoral condyle transfixing the physis.
The classification of frequencies in the γ Doradus / δ Scuti hybrid star HD 49434
E. Brunsden,K. R. Pollard,P. L. Cottrell,K. Uytterhoeven,D. J. Wright,P. De Cat
Physics , 2014, DOI: 10.1093/mnras/stu2615
Abstract: Hybrid stars of the {\gamma} Doradus and {\delta} Scuti pulsation types have great potential for asteroseismic analysis to explore their interior structure. To achieve this, mode identi- fications of pulsational frequencies observed in the stars must be made, a task which is far from simple. In this work we begin the analysis by scrutinizing the frequencies found in the CoRoT photometric satellite measurements and ground-based high-resolution spectroscopy of the hybrid star HD 49434. The results show almost no consistency between the frequencies found using the two techniques and no characteristic period spacings or couplings were identified in either dataset. The spectroscopic data additionally show no evidence for any long term (5 year) variation in the dominant frequency. The 31 spectroscopic frequencies identified have standard deviation profiles suggesting multiple modes sharing (l, m) in the {\delta} Scuti frequency region and several skewed modes sharing the same (l, m) in the {\gamma} Doradus frequency region. In addition, there is a clear frequency in the {\gamma} Doradus frequency region that appears to be unrelated to the others. We conclude HD 49434 remains a {\delta} Scuti/ {\gamma} Doradus candidate hybrid star but more sophisticated models dealing with rotation are sought to obtain a clear picture of the pulsational behaviour of this star.
Spectroscopic Pulsational Frequency Identification and Mode Determination of γ Doradus Star HD 12901
E. Brunsden,K. R. Pollard,P. L. Cottrell,D. J. Wright,P. De Cat
Physics , 2012, DOI: 10.1111/j.1365-2966.2012.22125.x
Abstract: Using multi-site spectroscopic data collected from three sites, the frequencies and pulsational modes of the {\gamma} Doradus star HD 12901 were identified. A total of six frequencies in the range 1-2 c/d were observed, their identifications supported by multiple line-profile measurement techniques and previously-published photometry. Five frequencies were of sufficient signal-to-noise for mode identification and all five displayed similar three-bump standard deviation profiles which were fitted well with (l,m)=(1,1) modes. These fits had reduced chi-squared values of less than 18. We propose that this star is an excellent candidate to test models of non-radially pulsating {\gamma} Doradus stars as a result of the presence of multiple (1,1) modes.
Severe Symmetric and Chronic Lower Eyelid Lymphedema in the Setting of Neck Surgery and Psoriasis  [PDF]
Michael E. Possin, Cat N. Burkat
Open Journal of Ophthalmology (OJOph) , 2012, DOI: 10.4236/ojoph.2012.24022
Abstract: Purpose: To present a patient with bilateral severe and symmetric lower lid lymphedema in the setting of previous neck surgery and chronic psoriasis, and to review the potential relationships of neck surgery, irradiation, psoriasis, and rosacea to chronic lymphedema. Design: Single case report with literature review. Methods: A 60-year-old female with long-standing psoriasis presented with a 2-year history of severe, symmetric bilateral lower eyelid edema that developed after total laryngectomy and selective right neck dissection for recurrent Squamous Cell Carcinoma (SCC). 10 years prior she underwent radiation and radical left neck dissection for metastatic disease. Surgical management entailed transcutaneous debulking of the masses combined with ectropion repair and suture tarsorrhaphy. A comprehensive literature review was performed using Pubmed and Medline. Results: Surgical debulking of the soft tissue masses via a transcutaneous incision resulted in significant improvement in the patient’s lymphedema without recurrence at 5 months follow-up. Histopathologic findings were consistent with chronic eyelid lymphedema. Conclusions: Isolated eyelid lymphedema is rare, with many etiologies, and poses a diagnostic challenge. While ophthalmologists are familiar with the ocular manifestations of rosacea such as conjunctivitis or blepharitis, it is important to consider rosacea as an etiology of eyelid lymphedema. Reviewing the history for previous surgery or radiation to the head and neck, or other dermatologic inflammatory disorders is also warranted. Rosaceous lymphedema is typically less severe than in post-surgical/radiation patients, and does not respond well to medical treatment; however, it often shows a favorable response to debulking blepharoplasty surgery, with or without skin grafting. This patient with a history of severe psoriasis and bilateral neck dissections with radiation for SCC also responded well to surgery without recurrence of lymphedema. Therefore, surgical debulking can be considered in these patients with severe eyelid lymphedema as an option to markedly improve visual function and overall cosmetic appearance.
Naturaleza, severidad y situación actual de los desórdenes por deficiencia de yodo
Terry Berro,Blanca;
Revista Cubana de Higiene y Epidemiolog?-a , 2008,
Abstract: aim: to give information to the health professionals about general aspects of iodine in the organism, its physiological function, the historical and geoecological aspects related to its deficiency, and the world and national panorama. development: an updated review of the national and international literature was made, emphasizing the magnitude and severity of this type of deficiency, its impact on health, and the world and national situation. conclusions: it was evidenced the significance of the systematic monitoring of iodine in salt, the urinary excretion, and the surveys on iodized salt consumption, as suitable indicators to diagnose and control iodine nutrition in populations and in the evaluation of programs.
Cuba: Manejo de residuales líquidos y evaluación de impacto ambiental
Terry Berro,Carmen C;
Revista Cubana de Higiene y Epidemiolog?-a , 2001,
Abstract: summary the way in which the fluid waste management was dealt with in the evaluation of the environmental impact implemented in the country since 1995 was analyzed. the potentialities of this process to assure higher qualitative levels of conservation and protection of the environment as the economic and social development of the country is guaranteed are shown. methodological elements for the correct identification and assessment of the positive and negative impacts produced by the activities of treatment and final disposal of the fluid waste generated in the new development projects are given so that the sanitary engineering works be real measures to mitigate environmental pollution.
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