Concurrent π\pi-vector fields and energy beta-change

The present paper deals with an \emph{intrinsic} investigation of the notion of a concurrent $\pi$-vector field on the pullback bundle of a Finsler manifold $(M,L)$. The effect of the existence of a concurrent $\pi$-vector field on some important special Finsler spaces is studied. An intrinsic investigation of a particular $\beta$-change, namely the energy $\beta$-change ($\widetilde{L}^{2}(x,y)=L^{2}(x,y)+ B^{2}(x,y) with \ B:=g(\bar{\zeta},\bar{\eta})$;$\bar{\zeta} $being a concurrent$\pi$-vector field), is established. The relation between the two Barthel connections$\Gamma$and$\widetilde{\Gamma}$, corresponding to this change, is found. This relation, together with the fact that the Cartan and the Barthel connections have the same horizontal and vertical projectors, enable us to study the energy$\beta$-change of the fundamental linear connection in Finsler geometry: the Cartan connection, the Berwald connection, the Chern connection and the Hashiguchi connection. Moreover, the change of their curvature tensors is concluded. It should be pointed out that the present work is formulated in a prospective modern coordinate-free form.Comment: 27 pages, LaTex file, Some typographical errors corrected, Some formulas simpifie

Textos liturgicos coptos bohairicos concernientes a Abbā Samuel de Kalamūn y Julius de Akfahs

The figure of Julius of Akfahs as a biographer of the martyrs, as well as the key role played by Samuel of Kalamun in seventh-century Egyptian monasticism are of great importance. In order to evaluate the evolution of the veneration accorded to both we provide all the relevant liturgical texts, along with commentaries on them.La figura de Julius de Akfahs como biógrafo de mártires y el papel clave desempeñado por Samuel de Kalamūn en el monasticismo egipcio del siglo VII son de enorme importancia. Con el objetivo de valorar cómo evolucionó la veneración tributada a ambos ofrecemos todos los textos litúrgicos relacionados con ellos acompañados de comentarios a los mismos

Moisture estimation for precision agriculture through RF sensing

Convenient, non-obtrusive, low-cost, and accurate sensing of fruit moisture content is crucial for the scientific studies of Pomology and Viticulture and their associated agriculture. It can provide early indicators of yield estimation and crop health as well as providing data for food production and precision farming systems. With a focus on grapes, we introduce SING, a scheme that senses grape moisture content by utilizing RF signals but without physical contact with the fruit. In this thesis, we extend the investigation of the theoretical relationship between the dielectric properties and the moisture content of agricultural products to establish a sensing model in the 5 GHz band. To make the work practical, we are first to measure the dielectric properties of grape bunches (not individually as that would be destructive), presenting a unique measurement challenge as internal grapes are hidden. In doing so, we demonstrate that our technique precisely estimates moisture content to a high degree of accuracy (90%). Current RF sensing models to estimate moisture are destructive; they require samples to be constrained in containers. Our work is first to dispense with such impracticalities, and, without contact with the object, accurately measures non-uniform grape clusters in open space. We demonstrate that SING is superior to existing work in its ability to accurately measure the dielectric properties of non-uniform fruit objects and test this through both lab-based experimentation and preliminary outdoor vineyard tests. We also examine the transferability of SING’s approach to real-world scenarios.Open Acces

Einstein Geometrization Philosophy and Differential Identities in PAP-Geometry

The importance of Einstein's geometrization philosophy, as an alternative to the least action principle, in constructing general relativity (GR), is illuminated. The role of differential identities in this philosophy is clarified. The use of Bianchi identity to write the field equations of GR is shown. Another similar identity in the absolute parallelism geometry is given. A more general differential identity in the parameterized absolute parallelism geometry is derived. Comparison and interrelationships between the above mentioned identities and their role in constructing field theories are discussed.Comment: LaTeX file, 17 pages, comments and criticism are welcom

Frequency and power dependence of spin-current emission by spin pumping in a thin film YIG/Pt system

This paper presents the frequency dependence of the spin current emission in a hybrid ferrimagnetic insulator/normal metal system. The system is based on a ferrimagnetic insulating thin film of Yttrium Iron Garnet (YIG, 200 nm) grown by liquid-phase-epitaxy (LPE) coupled with a normal metal with a strong spin-orbit coupling (Pt, 15 nm). The YIG layer presents an isotropic behaviour of the magnetization in the plane, a small linewidth, and a roughness lower than 0.4 nm. Here we discuss how the voltage signal from the spin current detector depends on the frequency [0.6 - 7 GHz], the microwave power, Pin, [1 - 70 mW], and the in-plane static magnetic field. A strong enhancement of the spin current emission is observed at low frequencies, showing the appearance of non-linear phenomena.Comment: 7 pages, 5 figure

A note on “Stability and periodicity in dynamic delay equations” [Comput. Math. Appl. 58 (2009) 264–273]

AbstractThe purpose of this note is twofold: First we highlight the importance of an implicit assumption in [Murat Adıvar, Youssef N. Raffoul, Stability and periodicity in dynamic delay equations, Computers and Mathematics with Applications 58 (2009) 264–272]. Second we emphasize one consequence of the bijectivity assumption which enables ruling out the commutativity condition δ∘σ=σ∘δ on the delay function

Magnetic resonance studies of the fundamental spin-wave modes in individual submicron Cu/NiFe/Cu perpendicularly magnetized disks

Spin wave spectra of perpendicularly magnetized disks with trilayers consisting of a 100 nm permalloy (Py) layer sandwiched by two Cu layers of 30 nm, are measured individually with a Magnetic Resonance Force Microscope (MRFM). It is demonstrated by 3D micromagnetic simulations that in disks having sub-micron size diameters, the lowest energy spin wave mode of the saturated state is not spatially uniform but rather is localized at the center of the Py/Cu interface in the region of a minimum demagnetizing field

Immunoregulatory soluble CTLA-4 modifies effector T cell responses in systemic lupus erythematosus

Acknowledgments This work was supported by Arthritis Research UK (Grant no. 19282). We are grateful to Dr. Nick Fluck for his invaluable support in recruiting patients for the study, and Mrs. Vivien Vaughan for her invaluable expertise in recruiting study participants and maintaining ethical documentation.Peer reviewedPublisher PD

Detection of Lead in the Carbon-Rich, Very Metal-Poor Star LP625-44: A Strong Constraint on s-Process Nucleosynthesis at Low Metallicity

We report the detection of the Pb I 4057.8A line in the very metal-poor ([Fe/H]=-2.7), carbon-rich star, LP625-44. We determine the abundance of Pb ([Pb/Fe] = 2.65) and 15 other neutron-capture elements. The abundance pattern between Ba and Pb agrees well with a scaled solar system s-process component, while the lighter elements (Sr-Zr) are less abundant than Ba. The enhancement of s-process elements is interpreted as a result of mass transfer in a binary system from a previous AGB companion, an interpretation strongly supported by radial velocity variations of this system. The detection of Pb makes it possible, for the first time, to compare model predictions of s-process nucleosynthesis in AGB stars with observations of elements between Sr and Pb. The Pb abundance is significantly lower than the prediction of recent models (e.g., Gallino et al. 1998), which succeeded in explaining the metallicity dependence of the abundance ratios of light s-elements (Sr-Zr) to heavy ones (Ba-Dy) found in previously observed s-process-enhanced stars. This suggests that one should either (a) reconsider the underlying assumptions concerning the 13C-rich s-processing site (13C-pocket) in the present models, or (b) investigate alternative sites of s-process nucleosynthesis in very metal-poor AGB stars.Comment: 10 pages, 3 figures, Astrophysical Journal Letters, in pres