1,069 research outputs found

    Air-sea interaction in tropical atmosphere: influence of ocean mixing on atmospheric processes

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    One the major factors determining the development and evolution of atmospheric convection is the sea surface temperature and its variability. Results of this thesis show that state of atmospheric convection impacts the diurnal distribution of thermal energy in the upper ocean. Under calm and clear sky conditions a shallow warm layer of several meters depth develops on the surface of the ocean. This warm layer drives an anomalous flux from the ocean to the atmosphere. A novel Kelvin wave trajectory database based on satellite data is introduced in this study. The investigation of its data shows that substantial fraction of Kelvin waves is initiated as a result of interaction with another Kelvin wave. Two distinct categories are defined and analyzed: the two- and multiple Kelvin wave initiations, and a spin off initiation. Results show that primary forcing of such waves are high diurnal cycle and/or increased wind speed and latent heat flux at the ocean surface. Variability of the ocean surface and subsurface along Kelvin wave trajectories over Indian Ocean is investigated: wind speed and latent heat flux increase and a sea surface temperature anomaly decreases during a wave passage. It is also shown that Kelvin waves are longitude-diurnal cycle phase locked over the Maritime Continent. This cycle phase locking is such that it agrees with mean, local diurnal cycle of convection in the atmosphere. The strength of the longitude-diurnal cycle phase locking differs between non-blocked Kelvin waves, which make successful transition over the Maritime Continent, and blocked waves that terminate within it. The distance between the islands of Sumatra and Borneo agrees with the distance travelled by an average Kelvin wave in one day. This suggests that the Maritime Continent may act as a filter, favoring successful propagation waves, which are in phase with the local diurnal cycle of convection.Comment: PhD thesis, University of Warsa

    Next-to-leading term of the renormalized stress-energy tensor of the quantized massive scalar field in Schwarzschild spacetime. The back reaction

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    The next-to-leading term of the renormalized stress-energy tensor of the quantized massive field with an arbitrary curvature coupling in the spacetime of the Schwarzschild black hole is constructed. It is achieved by functional differentiation of the DeWitt-Schwinger effective action involving coincidence limit of the Hadamard-Minakshisundaram-DeWitt-Seely coefficients a3a_{3} and a4.a_{4}. The back reaction of the quantized field upon the Schwarzschild black hole is briefly discussed

    How Does Length of Fieldwork Period Influence Non-Response? Findings from ESS 2 in Poland

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    In this paper we show how one method of increasing the response rate, i.e. an extension of the fieldwork period, influences the structure of non-response and the differences between respondents and non-respondents. We used data from the Pilot Study and the Main Study for the European Social Survey, Round 2, and from follow-up studies conducted after each of those. The fieldwork period of the Pilot Study was 11 days and the one of the Main Study was nearly 2.5 months. The follow-up study involved distributing a mail questionnaire to people who did not participate in the face-to-face survey (non-respondents). Extension of the fieldwork period brought a relatively modest increase in the response rate. However, a comparison of differences between the respondents and non-respondents for a short and a long fieldwork period demonstrated that those differences occurred in demographic variables and in opinion questions. We also compared the effect of the length of fieldwork period on differences between the respondents and two categories of non-respondents: refusers and inaccessibles for other reasons. We did not find any effect of the length of the fieldwork period on differences between respondents and inaccessibles for other reasons, neither in socio-demographics nor in opinion questions. However, the effect did occur when we compared respondents and refusers

    Are Non-Respondents Similar to Respondents? Findings from the ESS-2004 in Poland

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    In Poland, like in other countries, participation in surveys is declining over time. The growing non-response rates increase a risk of systematic bias of the results depending on the differences between non-respondents and respondents. In this article we attempt to assess how different are non-respondents from the survey participants in Poland. I approaching this question we refer to the two basic hypotheses concerning non-responses. The first hypothesis concerns the relationship between participation in surveys and the socio economic status (SES); the second hypothesis concerns relationship between the participation and social involvement/social isolation, and liberalism/conservatism. These hypotheses are tested using data from the pilot study of the European Social Survey 2004 and the main ESS 2004. Our analyses reveal that both the socio-demographic and the socio-psychological characteristics of individuals affect the non-response in Poland in a specific way

    Evaluation of radiological and clinical efficacy of ^{90}Y-DOTATATE} therapy in patients with progressive metastatic midgut neuroendocrine carcinomas

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    Background: To evaluate the radiological and clinical therapeutic effectiveness of ^{90}Y-octreotate [DOTATATE] inpatients with progressive somatostatin receptor-positive midgut neuroendocrine carcinomas (GEPNETs). Material/Methods: The study group: 34 patients, with histological proven extensive non-resectable and progressive midgut GEP-NETs. Radionuclide therapy (^{90}Y-DOTATATE) was given i.v. with a mean activity per administration 3,82 GBq. Initial clinical tumor responses were assessed 6-7 weeks after therapy completion and then once 3-monthly. The objective tumor response was classified according to the RECIST, initially between 4-6 months and then after each of the 6 months interval. Results: At 6 months after treatment completion, radiological tumor response was observed in 6 subjects with PR (19%), 25 presented SD (78%) and single had PD (3%). Overall clinical response to therapy at 6 months follow-up was observed in 23 patients (68%), SD in 5 patients (15%) and PD in 6 (18%). A year after therapy radiological tumour response was seen in 11 patients (44%), SD had 12 subjects (44%) and DP was noted in 2 patients. Two years after completed therapy PR was seen in 6 patients (33%), SD in additional 11 subjects (61%), single patient had PD. Clinical response to treatment in terms of PR and SD were noted in 22 patients (88%) after 1 year and in 14 patients (87%) after 2 years. Median PFS was 20 months, while the median OS was 23 months. In the 6 patients with clinical PD within initial 6 months the median PFS was 6 months and OS 11 months, while in those with SD or PR PFS was 22 months and OS 26 months (P<0.05). Conclusions: Therapy with ^{90}Y-DOTATATE} is effective in terms of clinical response, however the radiological response measured by the RECIST criteria underestimates benefits of this type of therapy in patients with progressive somatostatin receptor-positive midgut neuroendocrine carcinomas

    Regular black holes in an asymptotically de Sitter universe

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    A regular solution of the system of coupled equations of the nonlinear electrodynamics and gravity describing static and spherically-symmetric black holes in an asymptotically de Sitter universe is constructed and analyzed. Special emphasis is put on the degenerate configurations (when at least two horizons coincide) and their near horizon geometry. It is explicitly demonstrated that approximating the metric potentials in the region between the horizons by simple functions and making use of a limiting procedure one obtains the solutions constructed from maximally symmetric subspaces with different absolute values of radii. Topologically they are AdS2Ă—S2AdS_{2}\times S^{2} for the cold black hole, dS2Ă—S2dS_{2}\times S^{2} when the event and cosmological horizon coincide, and the Pleba\'nski- Hacyan solution for the ultraextremal black hole. A physically interesting solution describing the lukewarm black holes is briefly analyze

    The Araucaria Project. The distance to the Small Magellanic Cloud from late-type eclipsing binaries

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    We present a distance determination to the Small Magellanic Cloud (SMC) based on an analysis of four detached, long period, late type eclipsing binaries discovered by the OGLE Survey. The components of the binaries show negligible intrinsic variability. A consistent set of stellar parameters was derived with low statistical and systematic uncertainty. The absolute dimensions of the stars are calculated with a precision of better than 3%. The surface brightness - infrared color relation was used to derive the distance to each binary. The four systems clump around a distance modulus of (m - M)=18.99 with a dispersion of only 0.05 mag. Combining these results with the distance published by Graczyk et al. for the eclipsing binary OGLE SMC113.3 4007 we obtain a mean distance modulus to the SMC of 18.965 +/- 0.025 (stat.) +/- 0.048 (syst.) mag. This corresponds to a distance of 62.1 +/- 1.9 kpc, where the error includes both uncertainties. Taking into account other recent published determinations of the SMC distance we calculated the distance modulus difference between the SMC and the LMC equal to 0.458 +/- 0.068 mag. Finally we advocate mu_{SMC}=18.95 +/- 0.07 as a new "canonical" value of the distance modulus to this galaxy.Comment: Accepted for publication in Ap

    Dynamics of the Born-Infeld dyons

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    The approach to the dynamics of a charged particle in the Born-Infeld nonlinear electrodynamics developed in [Phys. Lett. A 240 (1998) 8] is generalized to include a Born-Infeld dyon. Both Hamiltonian and Lagrangian structures of many dyons interacting with nonlinear electromagnetism are constructed. All results are manifestly duality invariant.Comment: 11 pages, LATE
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