317 research outputs found

    Microlocal spectrum condition and Hadamard form for vector-valued quantum fields in curved spacetime

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    Some years ago, Radzikowski has found a characterization of Hadamard states for scalar quantum fields on a four-dimensional globally hyperbolic spacetime in terms of a specific form of the wavefront set of their two-point functions (termed `wavefront set spectrum condition'), thereby initiating a major progress in the understanding of Hadamard states and the further development of quantum field theory in curved spacetime. In the present work, we extend this important result on the equivalence of the wavefront set spectrum condition with the Hadamard condition from scalar fields to vector fields (sections in a vector bundle) which are subject to a wave-equation and are quantized so as to fulfill the covariant canonical commutation relations, or which obey a Dirac equation and are quantized according to the covariant anti-commutation relations, in any globally hyperbolic spacetime having dimension three or higher. In proving this result, a gap which is present in the published proof for the scalar field case will be removed. Moreover we determine the short-distance scaling limits of Hadamard states for vector-bundle valued fields, finding them to coincide with the corresponding flat-space, massless vacuum states.Comment: latex2e, 41 page

    Effect of enriched rotifer (Brachionus plicatilis) with probiotic lactobacilli on growth, survival and resistance indicators of western white shrimp (Litopenaeus vannamei) larvae

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    This study examined the effects of a commercial Lactobacillus probiotic on growth, survival and resistance of western white shrimp (Litopenaeus vannamei) larvae against salinity and formalin stresses in the Persian Gulf and Oman Sea Ecology Research Center. In this experiment, larvae were fed 6 times a day from mysis I (M1) step to post larvae 5 over 3 treatments including a control treatment C (without probiotic) and 2 experimental treatments namely A (having probiotic enriched rotifer) and B (having probiotic enriched rotifer and adding probiotic powder directly to the water). Larvae were stocked in 9 plastic tanks (20-liter) containing 10 L of seawater at a density of 50 larvae per liter. Three replicates were used for each treatment. At the end of the experimental period biometric larvae were studied under salinity and formalin stresses. Results showed that using probiotic bacteria had significant and positive effects on shrimp resistance, survival and growth (p0.05). According to the results we may conclude that the use of probiotic powder is effective in increasing growth, survival and resistance rate of western white shrimp in the larval and post larval stages

    Continuity of symplectically adjoint maps and the algebraic structure of Hadamard vacuum representations for quantum fields on curved spacetime

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    We derive for a pair of operators on a symplectic space which are adjoints of each other with respect to the symplectic form (that is, they are sympletically adjoint) that, if they are bounded for some scalar product on the symplectic space dominating the symplectic form, then they are bounded with respect to a one-parametric family of scalar products canonically associated with the initially given one, among them being its ``purification''. As a typical example we consider a scalar field on a globally hyperbolic spacetime governed by the Klein-Gordon equation; the classical system is described by a symplectic space and the temporal evolution by symplectomorphisms (which are symplectically adjoint to their inverses). A natural scalar product is that inducing the classical energy norm, and an application of the above result yields that its ``purification'' induces on the one-particle space of the quantized system a topology which coincides with that given by the two-point functions of quasifree Hadamard states. These findings will be shown to lead to new results concerning the structure of the local (von Neumann) observable-algebras in representations of quasifree Hadamard states of the Klein-Gordon field in an arbitrary globally hyperbolic spacetime, such as local definiteness, local primarity and Haag-duality (and also split- and type III_1-properties). A brief review of this circle of notions, as well as of properties of Hadamard states, forms part of the article.Comment: 42 pages, LaTeX. The Def. 3.3 was incomplete and this has been corrected. Several misprints have been removed. All results and proofs remain unchange

    Pengaruh Pengeluaran Pemerintah, Tenaga Kerja dan Investasi Terhadap Pertumbuhan Ekonomi di Provinsi Aceh

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    Penelitian ini bertujuan untuk menganalisis dan mengetahui seberapa besar pengaruh secara parsial maupun simultan variabel pengeluaran pemerintah, tenaga kerja dan investasi terhadap pertumbuhan ekonomi dengan menggunakan data tahun 1990 – 2020. Penelitian ini merupakan penelitian kuantitatif dengan menggunakan data runtun waktu sekunder, data diperoleh dari BPS dan NSWI. Metode yang digunakan adalah linier berganda (OLS) dengan uji asumsi klasik. Hasil penelitian menunjukkan bahwa secara parsial belanja pemerintah memiliki nilai prob 0,000 < 0,05 dan dibuktikan dengan nilai thitung > ttabel dimana 7,10265 > 1,70329 artinya belanja pemerintah berpengaruh positif dan signifikan terhadap pertumbuhan ekonomi dan investasi memiliki nilai -0,02 < 0,05 yang berarti berpengaruh negatif dan signifikan terhadap pertumbuhan ekonomi. pertumbuhan ekonomi dibuktikan dengan thitung dan ttabel dimana -2,401442 > 1,70329. Sedangkan angkatan kerja dengan nilai 0,30 > 0,05 bahwa tenaga kerja tidak berpengaruh signifikan dan signifikan terhadap pertumbuhan ekonomi thitung > ttabel dimana 1,0427 > 1,70329. Secara simultan nilai ketiga variabel tersebut ditunjukkan dengan nilai F prob sebesar 0,000 < 0,05 yang berarti ketiga variabel tersebut secara bersama-sama mempunyai pengaruh yang signifikan terhadap pertumbuhan ekonomi

    Gall-inducing Aphids (Hemiptera: Aphidoidea: Eriosomatinae) Associated with Salicaceae and Ulmaceae in Razavi Khorasan Province, with New Records for Fauna of Iran

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    A survey of gall-inducing aphids on elm and poplar trees was carried out during 2017 in Razavi Khorasan province, NE Iran. As a result, 15 species of gall-inducing aphids from 5 genera, all belonging to the subfamily Eriosomatinae, were recorded on 6 host plant species. The collected species included the genera Eriosoma, Kaltenbachiella, Pemphigus, Tetraneura and Thecabius. Pemphigus passeki Börner (Hemiptera: Aphididae) and Pemphigus populinigrae (Schrank) (Hemiptera: Aphididae) on Populus nigra var. italica (Salicaceae) were new records for the Iranian aphid fauna. Both new recorded species belong to the tribe Pem-phigini, subfamily Eriosomatinae. Among the identified species, 8 aphid species were new records for Razavi Khorasan province

    A Study on the Second Year Students' Ability of SMP As-shofa Pekanbaru in Constructing Yes/no Questions

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    This research was about the ability of the students in constructing yes/no questions. The aim of this research was to find out the ability of the second year students of SMP As-Shofa Pekanbaru in constructing yes/no questions. The population was 138 students. The sample was chosen through cluster random sampling and lottery technique. The analysis was based on giving test to the students. It was found that 20 out of 138 students were 1 student (5%) in excellent level, 5 students (25%)in good level, 10 students (50%) in mediocre level, 2 students (10%) in poor level and 2 students (10%) in very poor level. The mean score of the students was 51,81. It implies that the students' ability falls into mediocre ability level. Based on the result, it is recommended that teachers should pay attention more on material yes/no questions escpecially in using did

    Simulations of ionospheric turbulence produced by HF heating near the upper hybrid layer

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    Heating of the ionosphere by high-frequency (HF), ordinary (O) mode electromagnetic waves can excite magnetic field aligned density striations (FAS), associated with upper and lower hybrid turbulence and electron heating. We have used Vlasov simulations in one spatial and two velocity dimensions to study the induced turbulence in the presence of striations when the O-mode pump is mode converted to large amplitude upper hybrid oscillations trapped in a striation. Parametric processes give rise to upper and lower hybrid turbulence, as well as to large amplitude, short wavelength electron Bernstein waves. The latter excite stochastic electron heating when their amplitudes exceed a threshold for stochasticity, leading to a rapid increase of the electron temperature by several thousands of Kelvin. The results have relevance for high latitude heating experiments
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