On the Frequency Distribution of Restricted Proper Motions

Structure of proper motions in a sunspot penumbra

The dangers of deprojection of proper motions

We re-examine the method of deprojection of proper motions, which has been used for finding the velocity ellipsoid of stars in the nearby Galaxy. This method is only legitimate if the lines of sight to the individual stars are uncorrelated with the stars’ velocities. Very simple models are used to show that spurious results similar to ones recently reported are obtained when velocity dispersion...

Constraining the Proper Motions of Two Magnetars

We attempt to measure the proper motions of two magnetars — the soft gamma-ray repeater SGR 1900+14 and the anomalous X-ray pulsar 1E 2259+586 — using two epochs of Chandra observations separated by ∼ 5 yr. We perform extensive tests using these data, archival data, and simulations to verify the accuracy of our measurements and understand their limitations. We find 90% upper limits on the prope...

survey on the rule of the due & hindering relying on the sheikh ansaris ideas

قاعده مقتضی و مانع در متون فقهی کم و بیش مستند احکام قرار گرفته و مورد مناقشه فقهاء و اصولیین می باشد و مشهور معتقند مقتضی و مانع، قاعده نیست بلکه یکی از مسائل ذیل استصحاب است لذا نگارنده بر آن شد تا پیرامون این قاعده پژوهش جامعی انجام دهد. به عقیده ما مقتضی دارای حیثیت مستقلی است و هر گاه می گوییم مقتضی احراز شد یعنی با ماهیت مستقل خودش محرز گشته و قطعا اقتضاء خود را خواهد داشت مانند نکاح که ...

the effect of taftan pozzolan on the compressive strength of concrete in the environmental conditions of oman sea (chabahar port)

cement is an essential ingredient in the concrete buildings. for production of cement considerable amount of fossil fuel and electrical energy is consumed. on the other hand for generating one tone of portland cement, nearly one ton of carbon dioxide is released. it shows that 7 percent of the total released carbon dioxide in the world relates to the cement industry. considering ecological issu...