3,073 research outputs found
Specific heat of a non-local attractive Hubbard model
The specific heat of an attractive (interaction ) non-local Hubbard
model is investigated. We use a two-pole approximation which leads to a set of
correlation functions. In particular, the correlation function $\
G\delta\delta=1-n_Tn_T=n_{\uparrow}+n_{\downarrow}(0,\pm\pi)(\pm\pi,0)$ eliminates the two peak structure, the low
temperature peak remaining. The effects of the second nearest neighbor hopping
on the specific heat are also investigated.Comment: 5 pages, 7 figure
The mathematical theory of resonant transducers in a spherical gravity wave antenna
The rigoruos mathematical theory of the coupling and response of a spherical
gravitational wave detector endowed with a set of resonant transducers is
presented and developed. A perturbative series in ascending powers of the
square root of the ratio of the resonator to the sphere mass is seen to be the
key to the solution of the problem. General layouts of arbitrary numbers of
transducers can be assessed, and a specific proposal (PHC), alternative to the
highly symmetric TIGA of Merkowitz and Johnson, is described in detail.
Frequency spectra of the coupled system are seen to be theoretically recovered
in full agreement with experimental determinations.Comment: 31 pages, 7 figures, LaTeX2e, \usepackage{graphicx,deleq
Sub-nanosecond, time-resolved, broadband infrared spectroscopy using synchrotron radiation
A facility for sub-nanosecond time-resolved (pump-probe) infrared
spectroscopy has been developed at the National Synchrotron Light Source of
Brookhaven National Laboratory. A mode-locked Ti:sapphire laser produces 2 ps
duration, tunable near-IR pump pulses synchronized to probe pulses from a
synchrotron storage ring. The facility is unique on account of the broadband
infrared from the synchrotron, which allows the entire spectral range from 2
cm-1 (0.25 meV) to 20,000 cm-1 (2.5 eV) to be probed. A temporal resolution of
200 ps, limited by the infrared synchrotron-pulse duration, is achieved. A
maximum time delay of 170 ns is available without gating the infrared detector.
To illustrate the performance of the facility, a measurement of electron-hole
recombination dynamics for an HgCdTe semiconductor film in the far- and mid
infrared range is presented.Comment: 11 pages with 9 figures include
Técnica Embrapa de inseminação artificial transcervical em caprinos por meio de fixação cervical.
bitstream/item/57083/1/CT-43.pd
Técnica Embrapa de inseminação artificial transcervical em caprinos por meio de fixação cervical.
bitstream/item/81396/1/CT43.pd
Prevalensi dan Jenis Telur Cacing Soil Transmitted Helmints (STH) pada Sayuran Kemangi Pedagang Ikan Bakar di Kota Palu
Soil Transmitted Helminth (STH) adalah cacing golongan nematoda yang memerlukan tanah untuk perkembangan bentuk infektifnya. Di Indonesia golongan cacing yang penting dan menyebabkan masalah kesehatan masyarakat adalah Ascaris lumbricoides, Trichuris trichiura, dan cacing tambang yaitu :Necator americanus dan Ancylostoma duodenale. Masalah kesehatan yang ditimbulkan akibat kecacingan adalah anemia, obstruksi saluran empedu, radang pankreas, usus buntu, alergi, dan diare, penurunan fungsi kognitif (kecerdasan), kurang gizi, gangguan pertumbuhan, dan radang paru-paru. Tujuan penelitian ini adalah untuk mengetahui jenis telur cacing STH yang ditemukan pada sayur kemangi pada pedagang ikan bakar di Kota Palu. Metode penelitian ini adalah deskriptif observational dengan pendekatan cross sectional study, pemeriksaan sampel kemangi dengan metode pengendapan NaOH. Sebanyak 93 sampel daun kemangi kesimpulan ditemukan telur cacing sebesar 39,8%.Spesies telur cacing STH yang ditemukan yaitu Ascaris lumricoides 70,2%, Hookworm 16,2%, campuran Ascaris lumricoides dan Hookworm 10,8 %, Ascaris lumricoides dan Trichuris trichiura 2%. Perlu adanya pengawasan dan penyuluhan kepada pedagang warung makan mengenai kontaminasi telur cacing Soil Transmitted Helmints yang menyajikan sayuran mentah sebagai lalapan
Parâmetros genéticos de caracterÃsticas estimadas da curva de crescimento de ovinos da raça Santa Inês.
Resumo: Este trabalho foi realizado com os objetivos de estudar o ajuste das funções de Richards, Brody, Gompertz, Von Bertalanffy e LogÃstica sobre a curva de crescimento de ovinos Santa Inês e estimar parâmetros genéticos para caracterÃsticas calculadas a partir da função de melhor ajuste. Foram utilizadas apenas informações de fêmeas controladas entre os anos de 1993 e 2004, na Embrapa Tabuleiros Costeiros, e entre 1981 e 2004, na Embrapa Caprinos. Para o ajuste das curvas, as análises foram realizadas separadamente para cada rebanho, utilizando-se o procedimento NLIN do software Statistical Analysis System (SAS), por meio do método de GAUSS. Para determinar a função que melhor ajustava os dados, foram utilizados os critérios de coeficiente de determinação (R2), de quadrado médio residual (QMR) e o erro de predição médio (EM). No rebanho da Embrapa Tabuleiros Costeiros, todas as funções subestimaram os pesos, à exceção da curva de Richards. Diferentemente, todas as funções superestimaram o peso predito para o rebanho da Embrapa Caprinos. A curva de Richards foi a que promoveu melhor ajuste nos dois rebanhos. Os valores do peso adulto e da taxa de maturação estimados pela função de Richards foram de 54,38 kg e 0,00144/dia, respectivamente, para o rebanho da Embrapa Tabuleiros Costeiros, e 42,74 kg e 0,00260/dia, respectivamente, para o da Embrapa Caprinos. A função de Richards foi utilizada para estimar curvas individuais de crescimento dos animais. A partir destas curvas, foram estimadas várias caracterÃsticas de interesse econômico. Os parâmetros genéticos e os componentes de (co) variância para estas caracterÃsticas foram estimados pelo método da Máxima Verossimilhança Restrita Livre de Derivadas (DFREML), utilizando-se o software MTDFREML. As estimativas de herdabilidades direta e materna variaram, respectivamente, de 0,01 a 0,99 e de 0,00 a 0,13. É possÃvel alterar o padrão da curva de crescimento destes animais por meio de seleção. Genetic parameters for traits estimated from the growth curve of Santa Inês hair sheep. Abstract: The aim of this work was to study the adjustment of Richards, Brody, Gompertz, Von Bertalanffy and Logistic functions on the growth curve of Santa Inês hair sheep and to estimate genetic parameters for the traits obtained from the best fitting function. Information from females of the Embrapa Tabuleiros Costeiros herd recorded between 1993 and 2004 and from the Embrapa Caprinos herd recorded between 1981 and 2004 was used. Functions were fitted for each herd, using NLIN procedure of Statistical Analysis System software (SAS), by GAUSS method. The coefficient of determination (R2), residual mean square (QMR) and mean prediction error (EM) were the criteria used to determine the best fitting function. For the Embrapa Tabuleiros Costeiros herd, all the functions subestimated the weights, except the Richards function. On the other hand, all the functions superestimated the weights of animals from the Embrapa Caprinos herd. The best fitting in the both herds was obtained using the Richards function. The respective values of mature weight and maturation rate estimated by Richards function were 54.38 kg and 0.00144/day for Embrapa Tabuleiros Costeiros herd and 42.74 kg and 0.00260/day for Embrapa Caprinos herd. The Richards function was used to estimate individual growth curves of animals in order to estimate genetic parameters and the (co)variance components for traits of economic importance using the Derivative Free Restricted Maximum Likelihood method (DFREML). The estimates of direct and maternal heritabilities ranged, respectively, from 0.01 to 0.99 and 0.00 to 0.13 suggesting the possibility of changing the growth curve of Santa Ines sheep by selection
Relação entre a mancha parda (Bipolaris oryzae) na folha bandeira e a mancha de grão em genótipos de arroz.
A mancha de grãos é causada por um complexo de patógenos e vem sendo considerada como um dos principais problemas no cultivo de arroz. O objetivo do trabalho foi investigar a relação entre a resistência à mancha parda na folha bandeira e a mancha de grãos em condições controladas de casa de vegetação.Apresentação oral - graduação
Traversable wormholes coupled to nonlinear electrodynamics
In this work we explore the possible existence of static, spherically
symmetric and stationary, axisymmetric traversable wormholes coupled to
nonlinear electrodynamics. Considering static and spherically symmetric (2+1)
and (3+1)-dimensional wormhole spacetimes, we verify the presence of an event
horizon and the non-violation of the null energy condition at the throat. For
the former spacetime, the principle of finiteness is imposed, in order to
obtain regular physical fields at the throat. Next, we analyze the
(2+1)-dimensional stationary and axisymmetric wormhole, and also verify the
presence of an event horizon, rendering the geometry non-traversable.
Relatively to the (3+1)-dimensional stationary and axisymmetric wormhole
geometry, we find that the field equations impose specific conditions that are
incompatible with the properties of wormholes. Thus, we prove the non-existence
of the general class of traversable wormhole solutions, outlined above, within
the context of nonlinear electrodynamics.Comment: 9 pages, Revtex4. V2: major change in title; considerable additions
in the Introduction and in the rotating solution, no physics changes;
correction of a reference, one reference added; now 10 pages. This version to
appear in Classical and Quantum Gravit
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