8,776 research outputs found
A Relativistic Version of the Two-Level Atom in the Rest-Frame Instant Form of Dynamics
We define a relativistic version of the two-level atom, in which an extended
atom is replaced by a point particle carrying suitable Grassmann variables for
the description of the two-level structure and of the electric dipole. After
studying the isolated system "atom plus the electro-magnetic field" in the
electric-dipole representation as a parametrized Minkowski theory, we give its
restriction to the inertial rest frame and the explicit form of the Poincar\'e
generators. After quantization we get a two-level atom with a spin 1/2 electric
dipole and the relativistic generalization of the Hamiltonians of the Rabi and
Jaynes-Cummings models.Comment: 23 page
What can be learned from the schematic mode-coupling approach to experimental data ?
We propose a detailed investigation of the schematic mode-coupling approach
to experimental data, a method based on the use of simple mode-coupling
equations to analyze the dynamics of supercooled liquids. Our aim here is to
clarify different aspects of this approach that appeared so far uncontrolled or
arbitrary, and to validate the results obtained from previous works. Analyzing
the theoretical foundations of the approach, we first identify the parameters
of the theory playing a key role and obtain simple requirements to be met by a
schematic model for its use in this context. Then we compare the results
obtained from the schematic analysis of a given set of experimental data with a
variety of models and show that they are all perfectly consistent. A number of
potential biases in the method are identified and ruled out by the choice of
appropriate models. Finally, reference spectra computed from the mode-coupling
theory for a model simple liquid are analyzed along the same lines as
experimental data, allowing us to show that, despite the strong simplification
in the description of the dynamics it involves, the method is free from
spurious artifacts and provides accurate estimates of important parameters of
the theory. The only exception is the exponent parameter, the evaluation of
which is hindered, as for other methods, by corrections to the asymptotic laws
of the theory present when the dynamics is known only in a limited time or
frequency range.Comment: 13 pages, 5 figures, revtex4, to appear in J. Chem. Phy
Study of the Depolarized Light Scattering Spectra of Supercooled Liquids by a Simple Mode-Coupling Model
By using simple mode coupling equations, we investigate the depolarized light
scattering spectra of two so-called "fragile" glassforming liquids, salol
(phenylsalicylate) and CKN (Ca_{0.4}K_{0.6}(NO_3)_{1.4}), measured by Cummins
and coworkers. Nonlinear integrodifferential equations for the time evolution
of the density-fluctuations autocorrelation functions are the basic input of
the mode coupling theory. Restricting ourselves to a small set of such
equations, we fit the numerical solution to the experimental spectra. It leads
to a good agreement between model and experiment, which allows us to determine
how a real system explores the parameter space of the model, but it also leads
to unrealistic effective vertices in a temperature range where the theory makes
critical asymptotic predictions. We finally discuss the relevance and the range
of validity of these universal asymptotic predictions when applied to
experimental data on supercooled liquids.Comment: 31 LaTeX pages using overcite.sty, 10 postscript figures, accepted in
J. Chem. Phy
Effects of the Use of the Educreations Application in the Reading Comprehension of an Adolescent with Autism and Speech Delay
This paper is the final proposal that accompanies the poster presentation of the action research Effects of the Use of the Educreations Application in the Reading Comprehension of an Adolescent with Autism and Speech Delay in the 2015 South Florida Research Education Conference
Exploring Household Saving and Consumption-Smoothing in the Philippines
This paper explores whether or not the saving behavior of Filipino households fits the life-cycle hypothesis. Using pseudo-panels, which are constructed from the public use data files of the Family Income and Expenditures Survey of 1988 to 2000, it shows that consumption rises with the age of the household head and that the consumption profile has been rising for younger cohorts. The regressions indicate that the cohort-independent age effects on consumption simply track those on income across all ages, suggesting that Filipino households do not behave as the life-cycle hypothesis prescribes, possibly because they are liquidity constrained or impatient.consumption smoothing, household savings, household consumption
Exploring Household Saving and Consumption-Smoothing in the Philippines
This paper explores whether or not the saving behavior of Filipino households fits the life-cycle hypothesis. Using pseudo-panels, which are constructed from the public use data files of the Family Income and Expenditures Survey of 1988 to 2000, it shows that consumption rises with the age of the household head and that the consumption profile has been rising for younger cohorts. The regressions indicate that the cohort-independent age effects on consumption simply track those on income across all ages, suggesting that Filipino households do not behave as the life-cycle hypothesis prescribes, possibly because they are liquidity constrained or impatient.consumption smoothing, household savings, household consumption
Studi Aktivitas Masjid Kampus dan Pembinaan Iman dan Taqwa Bagi Mahasiswa di Perguruan Tinggi Umum (Studi ke Arah Perumusan Standardisasi Masjid Kampus dan Model Bina Imtaq di Ptu Jabar)
Campus mosque, as other mosques at the center of society, considered strategic in the creation of the religious atmosphere on campus. Campus mosque is not only as a center for ritual worship but also as a place of student activities. The mosque is a resource center, where the collection and distribution of zakat, the cadre and the development of Islamic religious knowledge take a place. The focus of this research is how the mosque campus activities and student religious activity, as well as how well the leadership expectations of PTU, DKM Masjid Campus administrators, students, PTU, and PTU lecturer PAI are against the activities of mosques and religious activities campus student. In particular, this study aims to determine the profile of the campus mosque, the mosque management campuses in Indonesia, the activity of the campus mosque, the substance of the material that is taught in PAI in the mosque and and the PTU, the number of credits of courses provided and PAI lecture method in PTU Jabar. The most relevant method in the study is descriptive-analytic, namely a study trying to uncover the problem is going to be described, analyzed, concluded and recommended to determine a policy. With this method the data are obtained and analyzed quantitatively and qualitatively. Research includes preparation of the TOR (Term of Reference), research instruments, testing the validity of the contents of the instrument, collect data, verify data, process the data, drafting of research reports, seminars, research, revision of research reports, research reports as well as doubling the research report
Simulating the Impact of Macroeconomic Policy Changes on Macronutrient Availability in Households
This study estimates a system of food demand equations utilizing nationally representative survey data. These estimates are then used to set-up a model that can use price and income changes from simulating a general equilibrium model to determine the impact of changes on macroeconomic policy on the nutritional status of households. Results indicate that the tariff reform program has a more progressive impact on nutrition than on income.computable general equilibrium (CGE)
Simulating the Impact of Macroeconomic Policy Changes on Macronutrient Availability in Households
This study estimates a system of food demand equations utilizing nationally representative survey data. These estimates are then used to set-up a model that can use price and income changes from simulating a general equilibrium model to determine the impact of changes on macroeconomic policy on the nutritional status of households. Results indicate that the tariff reform program has a more progressive impact on nutrition than on income.computable general equilibrium (CGE)
Motives and Giving Norms Behind Remittances: the Case of Filipino Overseas Workers and their Recipient Households
The literature has focused on motives to explain remittance behavior. But as non-anonymous transfers, remittances are liable to be influenced by giving norms as well. We formulate an empirical specification that takes account of remittance motives involving worker-household pairs. We find that altruism dominates the exchange motive among overseas workers who are likely to be the primary breadwinners of their recipient households. We also find that, in the subsample in which overseas workers are likely to be secondary breadwinners, (a) household labor income is an endogenous explanatory variable and (b) the error covariance of the household income and remittance selection equations is positive. A possible reason for (a) is that secondary breadwinners use household income as an imperfect signal of opportunity cost or to detect unobserved effort, i.e., moral hazard, in generating income. As for (b), we surmise that it indicates the presence of incentive-compatible mechanisms against moral hazard. On giving norms, we find that in samples that include overseas workers who are secondary breadwinners, remittance amounts are afflicted with negative selectivity. We present evidence that this is consistent with Filipino giving practices, in which everyone gives but in modest amounts.Remittances, remittance motives, giving norms
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