Brans-Dicke Gravity from Entropic Viewpoint

We interpret the Brans-Dicke gravity from entropic viewpoint. We first apply the Verlinde's entropic formalism in the Einstein frame, then perform the conformal transformation which connects the Einstein frame to the Jordan frame. The transformed result yields the equation of motion of the Brans-Dicke theory in the Jordan frame.Comment: Title changed, minor changes to match the published versio

USCID fourth international conference

Presented at the Role of irrigation and drainage in a sustainable future: USCID fourth international conference on irrigation and drainage on October 3-6, 2007 in Sacramento, California.In addition to increasingly frequent water shortage problems, agricultural water sector is also challenged by environmental issues. The objective of this article is to summarize, as well as propose sustainable strategies for agricultural sector in response to current environmental challenges. For water shortage problems, which are becoming more and more frequent worldwide including Taiwan, measures for irrigation water, such as extending irrigation periods, decreasing number of irrigation application times, or rotational irrigation, are introduced and discussed. When borrowing or transfer of water among sectors is needed in Taiwan, it is usually from agricultural irrigation water to other sectors in almost all cases. The maintenance of water right, and compensation to farmers for their income loss, are the two major issues. As for environmental changes, the impact of the accession of Taiwan to WTO (World Trade Organization) is discussed specifically in this article, and a management scheme in order to save irrigation water, which could be used for other purposes, is suggested in this article

From Molecular Cores to Planet-forming Disks: An SIRTF Legacy Program

Crucial steps in the formation of stars and planets can be studied only at mid‐ to far‐infrared wavelengths, where the Space Infrared Telescope (SIRTF) provides an unprecedented improvement in sensitivity. We will use all three SIRTF instruments (Infrared Array Camera [IRAC], Multiband Imaging Photometer for SIRTF [MIPS], and Infrared Spectrograph [IRS]) to observe sources that span the evolutionary sequence from molecular cores to protoplanetary disks, encompassing a wide range of cloud masses, stellar masses, and star‐forming environments. In addition to targeting about 150 known compact cores, we will survey with IRAC and MIPS (3.6–70 μm) the entire areas of five of the nearest large molecular clouds for new candidate protostars and substellar objects as faint as 0.001 solar luminosities. We will also observe with IRAC and MIPS about 190 systems likely to be in the early stages of planetary system formation (ages up to about 10 Myr), probing the evolution of the circumstellar dust, the raw material for planetary cores. Candidate planet‐forming disks as small as 0.1 lunar masses will be detectable. Spectroscopy with IRS of new objects found in the surveys and of a select group of known objects will add vital information on the changing chemical and physical conditions in the disks and envelopes. The resulting data products will include catalogs of thousands of previously unknown sources, multiwavelength maps of about 20 deg^2 of molecular clouds, photometry of about 190 known young stars, spectra of at least 170 sources, ancillary data from ground‐based telescopes, and new tools for analysis and modeling. These products will constitute the foundations for many follow‐up studies with ground‐based telescopes, as well as with SIRTF itself and other space missions such as SIM, JWST, Herschel, and TPF/Darwin

Instantonic approach to triple well potential

By using a usual instanton method we obtain the energy splitting due to quantum tunneling through the triple well barrier. It is shown that the term related to the midpoint of the energy splitting in propagator is quite different from that of double well case, in that it is proportional to the algebraic average of the frequencies of the left and central wells.Comment: Revtex, 11 pages, Included one eps figur

Existence of a phase transition under finite magnetic field in the long-range RKKY Ising spin glass Dyx_{x}Y1−x_{1-x}Ru2_{2}Si2_{2}

A phase transition of a model compound of the long-range Ising spin glass (SG) Dy$_{x}$Y$_{1-x}$Ru$_{2}$Si$_{2}$, where spins interact via the RKKY interaction, has been investigated. The static and the dynamic scaling analyses reveal that the SG phase transition in the model magnet belongs to the mean-field universality class. Moreover, the characteristic relaxation time in finite magnetic fields exhibits a critical divergent behavior as well as in zero field, indicating a stability of the SG phase in finite fields. The presence of the SG phase transition in field in the model magnet strongly syggests that the replica symmetry is broken in the long-range Ising SG.Comment: 4 pages, 4 figures, to be published in JPSJ (2010