Note on flat foliations of spherically symmetric spacetimes

It is known that spherically symmetric spacetimes admit flat spacelike foliations. We point out a simple method of seeing this result via the Hamiltonian constraints of general relativity. The method yields explicit formulas for the extrinsic curvatures of the slicings.Comment: 4 pages, to appear in PRD, reference added, typos correcte

Two dimensional general covariance from three dimensions

A 3d generally covariant field theory having some unusual properties is described. The theory has a degenerate 3-metric which effectively makes it a 2d field theory in disguise. For 2-manifolds without boundary, it has an infinite number of conserved charges that are associated with graphs in two dimensions and the Poisson algebra of the charges is closed. For 2-manifolds with boundary there are additional observables that have a Kac-Moody Poisson algebra. It is further shown that the theory is classically integrable and the general solution of the equations of motion is given. The quantum theory is described using Dirac quantization, and it is shown that there are quantum states associated with graphs in two dimensions.Comment: 10 pages (Latex), Alberta-Thy-19-9

Geographic Information System : Sistem Informasi Embuatan Model Pengendalian Kepemilikan Ternak Sapi Di Wilayah Provinsi NTB

Dengan besarnya potensi yang dimiliki tersebut pemerintah pusat menetapkan Nusa Tenggara Barat (NTB) sebagai salah satu propinsi sumber sapi potong dan sapi bibit diantara 18 propinsi di tanah air, sehingga kiprah NTB diharapkan mampu mempercepat program nasional percepatan pencapaian swasembada daging sapi (P2SDS). Oleh karena itu strategi yang dilakukan dalam mengembangkan potensi peternakan sapi ini adalah dengan memelihara sapi melalui sistem kandang kolektif untuk Pulau Lombok dan pola padang penggembalaan atau lar/so di Pulau Sumbawa. Sampai dengan pertengahan tahun 2010, terdapat sekitar 880 unit kandang kolektif sapi di pulau lombok dari target 1.000 unit kandang kolektif pada tahun 2013. Adanya jumlah sapi yang tiap tahun mengalami peningkatan maka dibutuhkan penelitian pembuatan sistem informasi giografis (SIG) dan database identifikasi peternak sapi. Penelitian ini dilakukan untuk menghasilkan produk SIG peternakan sapi dan database identitfikasi kepemilikan sapi di wilayah NTB. Metodologi penelitian digunakan adalah Model air terjun (waterfall) yaitu metode pengembangan sistem informasi dengan cara perencanaan, analisis, desain sistem, coding dan implementasi, sehingga produk dari SIG diperuntukan dapat menghasilkan pemetaan populasi sapi, database identifikasi kepemilikan sapi, jumlah kelompok tani, jumlah sapi yang dimiliki peternak, jumlah sapi yang terjual pasar tradisional, jumlah sapi yang disalurkan keluar daerah dan jumlah populasi yang ada di kabupaten di provinsi NTB

Einstein's equations and the chiral model

The vacuum Einstein equations for spacetimes with two commuting spacelike Killing field symmetries are studied using the Ashtekar variables. The case of compact spacelike hypersurfaces which are three-tori is considered, and the determinant of the Killing two-torus metric is chosen as the time gauge. The Hamiltonian evolution equations in this gauge may be rewritten as those of a modified SL(2) principal chiral model with a time dependent `coupling constant', or equivalently, with time dependent SL(2) structure constants. The evolution equations have a generalized zero-curvature formulation. Using this form, the explicit time dependence of an infinite number of spatial-diffeomorphism invariant phase space functionals is extracted, and it is shown that these are observables in the sense that they Poisson commute with the reduced Hamiltonian. An infinite set of observables that have SL(2) indices are also found. This determination of the explicit time dependence of an infinite set of spatial-diffeomorphism invariant observables amounts to the solutions of the Hamiltonian Einstein equations for these observables.Comment: 22 pages, RevTeX, to appear in Phys. Rev.

Canonical Quantization of the Gowdy Model

The family of Gowdy universes with the spatial topology of a three-torus is studied both classically and quantum mechanically. Starting with the Ashtekar formulation of Lorentzian general relativity, we introduce a gauge fixing procedure to remove almost all of the non-physical degrees of freedom. In this way, we arrive at a reduced model that is subject only to one homogeneous constraint. The phase space of this model is described by means of a canonical set of elementary variables. These are two real, homogeneous variables and the Fourier coefficients for four real fields that are periodic in the angular coordinate which does not correspond to a Killing field of the Gowdy spacetimes. We also obtain the explicit expressions for the line element and reduced Hamiltonian. We then proceed to quantize the system by representing the elementary variables as linear operators acting on a vector space of analytic functionals. The inner product on that space is selected by imposing Lorentzian reality conditions. We find the quantum states annihilated by the operator that represents the homogeneous constraint of the model and construct with them the Hilbert space of physical states. Finally, we derive the general form of the quantum observables of the model.Comment: 13 pages, Revte

A Brane Teaser

In this note we study the puzzle posed by two M5-branes intersecting on a string (or equivalently, a single M5-brane wrapping a holomorphic four-cycle in C^4). It has been known for a while that this system is different from all other configurations built using self-intersecting M-branes; in particular the corresponding supergravity solution exhibits various curious features which have remained unexplained. We propose that the resolution to these puzzles lies in the existence of a non-zero two-form on the M5-brane world-volume.Comment: 21 pages. References adde

evaluation of Lathyrus sativus cultivated in Ethiopia for proximate composition, minerals, β-ODAP and anti-nutritional components

Grass pea (Lathyrus sativus L.) is one of the most important food legumes in  countries like Bangladesh, India and Ethiopia. The legume is nutritious, rich in protein (28-32%) and contains good quantities of essential amino acids. Consumption of Lathyrus sativus seeds has been associated for more than 2000 years with neurolathyrim caused by the nearotoxin ß-ODAP (ß-N-Oxalyl-L-α, ßdiaminopropionic acid) present in the seeds. In the present study, Lathyrus  sativus seed samples  collected from the traditional grass pea growing areas in the country were analyzed for characteristics such as crude protein (CP), ß-ODAP, catechin equivalents (CE), trypsin inhibitor activity (TIA), 100 seed weight, seed color and consumption habit of grass pea seeds. The CP content ranged from 272.9 g/kg -1 to 319.8 g/kg -1 dry matter, the lowest and highest CP being observed in samples collected from Grar Jarso and Akaki, respectively. There were higher variations between samples in ß-ODAP levels. On average, ß-ODAP level in  samples from Akaki was about twofold higher than those from Asgido. CE, which detects simple flavonoids as well as condensed tannins, was not more than 7.66 g/kg-1 dry matter in any sample. The TIA content did not differ significantly between the samples. The correlation coefficients indicated that, ß-ODAP, CE, TIA and 100 seed weight were positively correlated (p<0.05) with CP. In contrast, CE and TIA were negatively correlated (p<0.05) with ß-ODAP. The dietary interviews revealed that grass pea has diversified uses in Ethiopia both as human food and  feed or crop. The habit of consuming shiro wot (the Ethiopian traditional spiced soup-like dish), kik wot (sauce made of dehusked split seeds) kollo (roasted whole seeds), nifro (boiled whole seeds) or kitta (unlearned flat bread) prepared from grass pea alone is significantly higher (p<0.05) than the habit of consuming those food items prepared from grass pea mixed with other legumes. Further studies are  warranted to understand the reasons that influenced food choices of the housewives for establishing respective ways to improve healthy consumption habits.Key words: consumption habit, Lathyrus sativus, ß-ODAP, tannins, trypsin inhibitor activity. Le petit pois (Lathyrus sativus L.) est l’une des légumineuses alimentaires les plus importantes dans des pays tels que le Bangladesh, l’Inde et l’Ethiopie. Les légumineuses sont nutritives, riches en protéines (28-32%) et elles contiennent de  bonnes quantités d’acides aminés essentiels. La consommation des graines de Lathyrus sativus a été associée pendant plus de 2000 ans au neurolathyrime causé par le néarotoxine ß-ODAP (ß-N-Oxalyl-L-α, l’acide ß- diaminopropionique) présentdans les graines. Au cours de la présente étude, des échantillons de graines de Lathyrus sativus collectés à partir des  régions où pousse le petit pois traditionnel dans le pays ont été analysés pour trouver des caractéristiques telles que les   protéines à l’état brut (CP), ß-ODAP, des équivalents de catéchine (CE), l’activité inhibitrice de trypsine (AIT), le poids de la graine 100, la couleur de la graine et les habitudes liées à la consommation des graines de petits pois. Le contenu de CP variait entre 272.9 g/kg -1 et 319.8 g/kg -1 de matière sèche, le niveau le plus bas et le plus élevé de CP étant observés dans des échantillons collectés à Grar Jarso et à Akaki, respectivement. Il y avait des variations plus élevées entre les    échantillons dans les niveaux de ß-ODAP. En moyenne, la teneur en ß-ODAP dans les échantillons d’Akaki était presque le double de celle des échantillons d’Asgido. CE, qui détecte de simples flavonoïdes et des tanins condensés, ne constituait pas plus de 7.66 g/kg-1 de matière sèche dans n’importe quel échantillon. La teneur en AIT ne différait pas beaucoup entre les échantillons. Les coefficients des  corrélations indiquaient que les poids des graines de ß-ODAP, CE, AIT et 100 avaient des corrélations positives (p<0.05) avec CP. Par contre, CE et AIT avaient une corrélation négative (p<0.05) avec ß-ODAP. Les interviews sur les régimes alimentaires ont révélé qu’en Ethiopie le petit pois est utilisé de manières  diversifiées à la fois en tant qu’aliment humain et en tant que ration de nourriture ou culture. L’habitude de consommer le shiro wot (un plat   traditionnel éthiopien épicé qui ressemble à de la soupe), le kik wot (sauce faite de graines cassées et décortiquées), le kollo (des graines entières rôties), le nifro (des graines entières bouillies) ou le kitta (un pain plat désappris), préparés à partir de petit pois  uniquement, est beaucoup plus répandue (p<0.05) que l’habitude de consommer ces denrées alimentaires  préparées à partir du petit pois mélangé avec d’autres légumineuses. Des études plus approfondies s’imposent pour   comprendre les  raisons qui ont influencé les choix des aliments chez les femmes au foyer pour établir les moyens respectifs d’améliorer des habitudes alimentaires saines.Mots-clés: habitude alimentaire, Lathyrus sativus, ß-ODAP, tanins, activité inhibitrice de trypsine.