The inner mass power spectrum of galaxies using strong gravitational lensing: beyond linear approximation

In the last decade the detection of individual massive dark matter sub-halos has been possible using potential correction formalism in strong gravitational lens imaging. Here we propose a statistical formalism to relate strong gravitational lens surface brightness anomalies to the lens potential fluctuations arising from dark matter distribution in the lens galaxy. We consider these fluctuations as a Gaussian random field in addition to the unperturbed smooth lens model. This is very similar to weak lensing formalism and we show that in this way we can measure the power spectrum of these perturbations to the potential. We test the method by applying it to simulated mock lenses of different geometries and by performing an MCMC analysis of the theoretical power spectra. This method can measure density fluctuations in early type galaxies on scales of 1-10 kpc at typical rms-levels of a percent, using a single lens system observed with the Hubble Space Telescope with typical signal-to-noise ratios obtained in a single orbit

New Records of Thecacineta cothurnioides and Trematosoma rotunda (Ciliophora, Suctorea) as epibionts on nematodes from the Indian Ocean

This article deals with the report of two suctorian ciliates species viz. Thecacineta cothurnioides Collin, 1909 and Trematosoma rotunda (Allgén, 1952 ) as epibionts on Tricoma sp. and Pseudochromadora sp. (Nematoda) respectively from Ratnagiri, west coast of India, Arabian Sea (Indian Ocean). Redescription of two species with distribution and nomenclatural notes are given. Both species are recorded here first time from Indian coast and the Indian Ocean. Genus Tricoma Cobb, 1894 is also recorded here first time as a host of Th. cothurnioides

An overview of Suctorian ciliates (Ciliophora, Suctorea) as epibionts of halacarid mites (Acari, Halacaridae)

Scant information is available regarding the prevalence and distribution of suctorian ciliates on halacarid mites. However, using this limited information and data from our laboratory on the systematics, biology, ecology and distribution of suctorian ciliates that are epibionts of halacarid mites, we redescribed four suctorian species: Limnoricus ceter (Jankowski), Praethecacineta halacari (Schulz), Thecacineta calix (Schroder) and Acineta sulcata Dons. We also recognized Lissacineta allgeni Jankowski and Thecacineta allgeni (Jankowski) as synonyms of Praethecacineta halacari (Schluz), and Thecacineta laophontis Jankowski and Paracineta moebiusi Kahl as synonyms of Thecacineta calix (Schroder). Many suctorians have been reported, but not properly identified in the halacarid literature. So, we have attempted to identify those suctorians to species level. Lastly, the interactions between the suctorians and their hosts are also discussed and Praethecacineta halacari is also reported for the first time from the Indian coast

Efficient Black-Box Identity Testing for Free Group Algebras

Hrubes and Wigderson [Pavel Hrubes and Avi Wigderson, 2014] initiated the study of noncommutative arithmetic circuits with division computing a noncommutative rational function in the free skew field, and raised the question of rational identity testing. For noncommutative formulas with inverses the problem can be solved in deterministic polynomial time in the white-box model [Ankit Garg et al., 2016; Ivanyos et al., 2018]. It can be solved in randomized polynomial time in the black-box model [Harm Derksen and Visu Makam, 2017], where the running time is polynomial in the size of the formula. The complexity of identity testing of noncommutative rational functions, in general, remains open for noncommutative circuits with inverses. We solve the problem for a natural special case. We consider expressions in the free group algebra F(X,X^{-1}) where X={x_1, x_2, ..., x_n}. Our main results are the following. 1) Given a degree d expression f in F(X,X^{-1}) as a black-box, we obtain a randomized poly(n,d) algorithm to check whether f is an identically zero expression or not. The technical contribution is an Amitsur-Levitzki type theorem [A. S. Amitsur and J. Levitzki, 1950] for F(X, X^{-1}). This also yields a deterministic identity testing algorithm (and even an expression reconstruction algorithm) that is polynomial time in the sparsity of the input expression. 2) Given an expression f in F(X,X^{-1}) of degree D and sparsity s, as black-box, we can check whether f is identically zero or not in randomized poly(n,log s, log D) time. This yields a randomized polynomial-time algorithm when D and s are exponential in n

Report of epibiont Thecacineta calix (Ciliophora: Suctorea) on deep sea Desmodora (Nematoda) from the Andaman Sea, Indian Ocean

Suctorian epibionts Thecacineta calix attached on the cuticle of nematodes Desmodora sphaerica and D. pontica are reported here from the deep sea hexactinellid sponge Pheronema sp. from the Andaman Sea (Indian Ocean). The epibiont T. calix is reported here for first time from the Andaman Sea

New records of Praethecacineta halacari (Schulz) (Suctorea: Ciliophora) from Taiwan, Tanzania and Canada

The present study reports on a range extension of the suctorian species Praethecacineta halacari to the region of He-Ping-Dao, north-east of Taiwan (West Pacific Ocean), Matemwe, the east coast of Unguja, Zanzibar, Tanzania (West Indian Ocean) and Nova Scotia, Canada (West Atlantic Ocean). Praethecacineta halacari is reported here for the first time from Taiwan, Tanzania and Canada. Earlier records include the Caspian Sea, Western Australia, Brazil, India, and various coastal sites in Europe

Cyclical Changes in the Timing Residuals from the Pulsar B0919+06

We report the detection of a large glitch in the pulsar B0919+06 (J0922+0638). The glitch occurred in 2009 November 5 (MJD 55140) and was characterized by a fractional increase in the rotation frequency of Deltanu/nu=1.3x10^{-6}. A large glitch happens in the pulsar whose rotation has unstable character. We present the results of the analysis of the rotation behavior of this pulsar over the 30-year time span from 1979 to 2009. These results show that the pulsar's rotation frequency underwent continuous, slow oscillations which look like glitch-like events. During the 1991-2009 interval, the pulsar experienced a continuous sequence of 12 slow glitches with a fractional increase in the rotation frequency Deltanu/nu=1.5x10^{-9}. All the slow glitches observed have a similar signature related to a slow increase in the rotation frequency during 200 days and the subsequent relaxation back to the pre-glitch value during 400 days. We show that a continuous sequence of such slow glitches is characterized by practically identical amplitudes equal to Deltanu=3.5x10^{-9} Hz and identical time intervals between glitches of about 600 days and is well described by a periodic sawtooth-like function. The detection of two different phenomena, such as a large glitch and a sequence of slow glitches, indicates the presence of two types of discontinuities in the rotation frequency of the pulsar B0919+06. These discontinuities can be classified as normal and slow glitches.Comment: 24 pages, 5 figures. Submitted to Ap