نتایج جستجو برای: dark

تعداد نتایج: 76079  

Journal: :Monthly Notices of the Royal Astronomical Society 2005

Journal: :EPL (Europhysics Letters) 2015

Syrian bean caper (Zygophyllum fabago L.) grows in dry and uncultivable wastelands. Because of high tolerance to adverse conditions, an experiment was designed and fulfilled to investigate the effect of two environmental factors, light and temperature, on Syrian bean caper seed germination. Experiment was performed in a completely randomized design with two levels of light (light and dark) and ...

Journal: :International Journal of Advanced Astronomy 2017

HOSSEIN HOSSEINZADEH, MASSUMEH FADISHEI,

The circadian variation of the toxicity and nociceptive actIvity of aminophylline as an important methylxanthine was studied in mice. The animals were housed under controlled light-dark cycles for at least 2 weeks. Acute toxicity was determined by LD50. Hot-plate test was used for determination of thermal pain threshold. Doses of 200, 250, 280 and 340 mg/kg of aminophylline were injected i...

2008
Philip D. Mannheim

We review the underpinnings of the standard Newton-Einstein theory of gravity, and identifywhere it could possibly go wrong. In particular, we discuss the logical independence from eachother of the general covariance principle, the equivalence principle and the Einstein equations, anddiscuss how to constrain the matter energy-momentum tensor which serves as the source of gravity.<lb...

2008
Roy Maartens

Observations provide increasingly strong evidence that the universe is accelerating. This revolutionary advance in cosmological observations confronts theoretical cosmology with a tremendous challenge, which it has so far failed to meet. Explanations of cosmic acceleration within the framework of general relativity are plagued by difficulties. General relativistic models are nearly all based on...

2008
Glennys R. Farrar P. J. E. Peebles

We discuss models for the cosmological dark sector in which the energy density of a scalar field approximates Einstein’s cosmological constant and the scalar field value determines the dark matter particle mass by a Yukawa coupling. A model with one dark matter family can be adjusted so the observational constraints on the cosmological parameters are close to but different from what is predicte...

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