Bethe--Salpeter equation in QCD

We extend to regular QCD the derivation of a confining $q \bar{q}$ Bethe--Salpeter equation previously given for the simplest model of scalar QCD in which quarks are treated as spinless particles. We start from the same assumptions on the Wilson loop integral already adopted in the derivation of a semirelativistic heavy quark potential. We show that, by standard approximations, an effective meson squared mass operator can be obtained from our BS kernel and that, from this, by ${1\over m^2}$ expansion the corresponding Wilson loop potential can be reobtained, spin--dependent and velocity--dependent terms included. We also show that, on the contrary, neglecting spin--dependent terms, relativistic flux tube model is reproduced.Comment: 23 pages, revte

Confining Bethe--Salpeter equation in QCD

We derive a confining $q \bar{q}$ Bethe--Salpeter equation starting from the same assumptions on the Wilson loop integral already adopted in the derivation of a semirelativistic heavy quark potential. We show that, by standard approximations, an effective meson squared mass operator can be obtained from our BS kernel and that, from this, by ${1\over m^2}$ expansion, the corresponding Wilson loop potential is recovered, spin--dependent and velocity--dependent terms included. We also show, that, on the contrary, neglecting spin--dependent terms, relativistic flux tube model is reproduced.Comment: 5 pages, Latex, talk given at the workshop CONFINEMENT95, 22-24 March, Osak

ANALISIS USAHATANI KEDELAI (Glycine Max) (Studi Kasus pada Kelompok Tani Harapan Maju Desa Cigugur Kecamatan Cigugur Kabupaten Pangandaran)

Penelitian ini bertujuan untuk mengetahui: (1) Besarnya rata-rata biaya yang dikeluarkan pada USAhatani kedelai per hektar per satu kali musim tanam di Kelompok Tani Harapan Maju Desa Cigugur Kecamatan Cigugur Kabupaten Pangandaran, (2) Besarnya rata-rata penerimaan dan rata-rata pendapatan yang diterima petani per hektar per satu kali musim tanam di di Kelompok Tani Harapan Maju Desa Cigugur Kecamatan Cigugur Kabupaten Pangandaran, (3) Besarnya ratarata R/C USAhatani kedelai per hektar per satu kali musim tanam di di Kelompok Tani Harapan Maju Desa Cigugur Kecamatan Cigugur Kabupaten Pangandaran. Jenis penelitian yang digunakan adalah studi kasus. Data yang dipergunakan adalah data primer dan data sekunder. Data primer diperoleh dari hasil wawancara dan kuesioner, sedangkan data sekunder diperoleh melalui studi pustaka, dinas dan instansi terkait. Jumlah responden sebanyak 40 petani kedelai yang diperoleh secara sensus. Analisis yang digunakan adalah biaya,penerimaan, pendapatan, dan R/C. Hasil penelitian ini menunjukkan bahwa:1. Rata-rata biaya total USAhatani kedelai di Kelompok Tani Harapan Maju Desa Cigugur Kecamatan Cigugur Kabupaten Pangandaran per hektar per satu kali musim tanam adalah Rp 5.347.495,08.2. Rata-rata penerimaan USAhatani kedelai di Kelompok Tani Harapan Maju Desa Cigugur Kecamatan Cigugur Kabupaten Pangandaran per hektar per satu kali musim tanam adalah Rp 7.376.292,00; dan rata-rata pendapatan dalam satu kali musim tanam adalah sebesar Rp 2.028.796,92.3. Rata-rata R/C per hektar per satu kali musim tanam adalah 1,42 artinya USAhatani kedelai di Kelompok Tani Harapan Maju Desa Cigugur Kecamatan Cigugur Kabupaten Pangandaran menguntungkan dan layak untuk diusahakan

A consistent derivation of the quark--antiquark and three quark potentials in a Wilson loop context

In this paper we give a new derivation of the quark-antiquark potential in the Wilson loop context. This makes more explicit the approximations involved and enables an immediate extension to the three-quark case. In the $q\overline{q}$ case we find the same semirelativistic potential obtained in preceding papers but for a question of ordering. In the $3q$ case we find a spin dependent potential identical to that already derived in the literature from the ad hoc and non correct assumption of scalar confinement. Furthermore we obtain the correct form of the spin independent potential up to the $1/m^2$ order.Comment: 30 pages, Revtex (3 figures available as hard copies only), IFUM 452/F

QCDOC: A 10-teraflops scale computer for lattice QCD

The architecture of a new class of computers, optimized for lattice QCD calculations, is described. An individual node is based on a single integrated circuit containing a PowerPC 32-bit integer processor with a 1 Gflops 64-bit IEEE floating point unit, 4 Mbyte of memory, 8 Gbit/sec nearest-neighbor communications and additional control and diagnostic circuitry. The machine's name, QCDOC, derives from ``QCD On a Chip''.Comment: Lattice 2000 (machines) 8 pages, 4 figure

Heavy Quarkonium Potential Model and the 1P1{}^1P_1 State of Charmonium

A theoretical explanation of the observed splittings among the P~states of charmonium is given with the use of a nonsingular potential model for heavy quarkonia. We also show that the recently observed mass difference between the center of gravity of the ${}^3P_J$ states and the ${}^1P_1$ state of $c\bar{c}$ does not provide a direct test of the color hyperfine interaction in heavy quarkonia. Our theoretical value for the mass of the ${}^1P_1$ state is in agreement with the experimental result, and its E1 transition width is 341.8~keV. The mass of the $\eta_c'$ state is predicted to be 3622.3~MeV.Comment: 15 page REVTEX documen

Large Possible retardation effects of quark confinement on the meson spectrum II

We present the results of a study of heavy-light-quark bound states in the context of the reduced Bethe-Salpeter equation with relativistic vector and scalar interactions. We find that satisfactory fits may also be obtained when the retarded effect of the quark-antiquark interaction is concerned.Comment: 11 pages, RevTex, to appear in PR

Comparison between in vitro chemical and ex vivo biological assays to evaluate antioxidant capacity of botanical extracts

The anti-oxidative activity of plant-derived extracts is well-known and confers health-promoting effects on functional foods and food supplements. Aim of this work is to evaluate the capability of two different assays to predict the real biological antioxidant efficiency. At this purpose, extracts from five different plant-derived matrices and commercial purified phytochemicals were analyzed for their anti-oxidative properties by using well-standardized in vitro chemical method (TEAC) and an ex vivo biological assay. The biological assay, a cellular membrane system obtained from erythrocytes of healthy volunteers, is based on the capability of phytochemicals treatment to prevent membrane lipid peroxidation under oxidative stress by UV-B radiation. Plant extracts naturally rich in phenols with different structure and purified phytochemicals showed different in vitro and ex vivo antioxidant capacities. A high correlation between phenolic contents of the plant-derived extracts and their ability to prevent oxidative injuries in a biological system was found, thus underlying the relevance of this class of metabolites in preventing oxidative stress. On the other hand, a low correlation between the antioxidant capacities was shown between in vitro and ex vivo antioxidant assay. Moreover, data presented in this work show how food complex matrices are more effective in preventing oxidative damages at biological level than pure phytochemicals, even if for these latter, the antioxidant activity was generally higher than that observed for food complex matrices

Possible retardation effects of quark confinement on the meson spectrum

The reduced Bethe-Salpeter equation with scalar confinement and vector gluon exchange is applied to quark-antiquark bound states. The so called intrinsic flaw of Salpeter equation with static scalar confinement is investigated. The notorious problem of narrow level spacings is found to be remedied by taking into consideration the retardation effect of scalar confinement. Good fit for the mass spectrum of both heavy and light quarkomium states is then obtained.Comment: 14 pages in LaTex for