Min-oscillations in Escherichia coli induced by interactions of membrane-bound proteins

During division it is of primary importance for a cell to correctly determine the site of cleavage. The bacterium Escherichia coli divides in the center, producing two daughter cells of equal size. Selection of the center as the correct division site is in part achieved by the Min-proteins. They oscillate between the two cell poles and thereby prevent division at these locations. Here, a phenomenological description for these oscillations is presented, where lateral interactions between proteins on the cell membrane play a key role. Solutions to the dynamic equations are compared to experimental findings. In particular, the temporal period of the oscillations is measured as a function of the cell length and found to be compatible with the theoretical prediction.Comment: 17 pages, 5 figures. Submitted to Physical Biolog

Is This a Joke? Detecting Humor in Spanish Tweets

While humor has been historically studied from a psychological, cognitive and linguistic standpoint, its study from a computational perspective is an area yet to be explored in Computational Linguistics. There exist some previous works, but a characterization of humor that allows its automatic recognition and generation is far from being specified. In this work we build a crowdsourced corpus of labeled tweets, annotated according to its humor value, letting the annotators subjectively decide which are humorous. A humor classifier for Spanish tweets is assembled based on supervised learning, reaching a precision of 84% and a recall of 69%.Comment: Preprint version, without referra

Pension Provision of “Special Types of Service” in System of State Apparatus of Russian Empire

The issue of the history of pension provision for “special types of service” in the Russian Empire is considered in the article. The provision of pensions for these categories of civil servants is seen as an important part of the government’s policy to stabilize the state apparatus. Attention is paid to the rules for assigning pensions to employees of departments: mining, communications, forestry, customs, court, educational and scientific. The results of a comparative analysis of pensions of these categories of employees with pensions of civil (and in some cases military) employees under the Pension Regulations of 1827 are presented. The privileged position of employees of “special types of services” in relation to other civil and military employees is shown. The question is raised about the history and causes of this privileged position. The novelty of the study is in the fact that for the first time the history of pension provision for special categories of civil servants is considered in a comprehensive manner. It has been proven that the privileged position of these categories of employees was a way to recruit for service in industries that required special qualifications or were distinguished by difficult conditions

Expenditures on Pensions and Benefits in State Budget of Russian Empire in 19th to Early 20th Century

The article deals with the issue of the place of expenditures for the payment of pensions and benefits in the structure of public expenditures of the Russian Empire. It is shown that the amount of expenditures on pensions in absolute terms constantly increased (from 1741 to 1913 by more than 13 times). Since the amount of pensions paid, determined by the Pension statute of 1827, remained unchanged until 1917, this growth was determined by a constant increase in the number of pension recipients. This increase was due to an increase in the number of civil servants. At the same time, the share of expenditures on pensions and benefits in the expenditure part of the budget of the Russian Empire (“ordinary expenses”) fluctuated, reaching a maximum (5.1%) in 1871 and a minimum (2.3%) in 1903-1904. These fluctuations were determined by changes in the amount of the expenditure part of the empire’s budget, which increased noticeably by the beginning of the 20th century. On the whole, expenditures on pension provision accounted for a significant part of budget expenditures, exceeding such significant expenditure items as, for example, the expenditures of the Ministry of Public Education or the Ministry of State Property (Ministry of Agriculture and State Property, Main Directorate of Land Management and Agriculture), although they were inferior to the expenditures of the Military Department. The insufficiency of the size of pensions, due to their invariability, was combined with the burdensomeness of pension expenditures for the state, but a radical reform of the pension system did not take place

Dynamic compartmentalization of bacteria: accurate division in E. coli

Positioning of the midcell division plane within the bacterium E. coli is controlled by the min system of proteins: MinC, MinD and MinE. These proteins coherently oscillate from end to end of the bacterium. We present a reaction--diffusion model describing the diffusion of min proteins along the bacterium and their transfer between the cytoplasmic membrane and cytoplasm. Our model spontaneously generates protein oscillations in good agreement with experiments. We explore the oscillation stability, frequency and wavelength as a function of protein concentration and bacterial length.Comment: 4 pages, 4 figures, Latex2e, Revtex

Detection of gravity modes in the massive binary V380 Cyg from Kepler spacebased photometry and high-resolution spectroscopy

We report the discovery of low-amplitude gravity-mode oscillations in the massive binary star V380 Cyg, from 180 d of Kepler custom-aperture space photometry and 5 months of high-resolution high signal-to-noise spectroscopy. The new data are of unprecedented quality and allowed to improve the orbital and fundamental parameters for this binary. The orbital solution was subtracted from the photometric data and led to the detection of periodic intrinsic variability with frequencies of which some are multiples of the orbital frequency and others are not. Spectral disentangling allowed the detection of line-profile variability in the primary. With our discovery of intrinsic variability interpreted as gravity mode oscillations, V380 Cyg becomes an important laboratory for future seismic tuning of the near-core physics in massive B-type stars.Comment: 5 pages, 4 figures, 2 tables. Accepted for publication in MNRAS Letter