The High Time Resolution Universe surveys for pulsars and fast transients

The High Time Resolution Universe survey for pulsars and transients is the first truly all-sky pulsar survey, taking place at the Parkes Radio Telescope in Australia and the Effelsberg Radio Telescope in Germany. Utilising multibeam receivers with custom built all-digital recorders the survey targets the fastest millisecond pulsars and radio transients on timescales of 64 us to a few seconds. The new multibeam digital filter-bank system at has a factor of eight improvement in frequency resolution over previous Parkes multibeam surveys, allowing us to probe further into the Galactic plane for short duration signals. The survey is split into low, mid and high Galactic latitude regions. The mid-latitude portion of the southern hemisphere survey is now completed, discovering 107 previously unknown pulsars, including 26 millisecond pulsars. To date, the total number of discoveries in the combined survey is 135 and 29 MSPs. These discoveries include the first magnetar to be discovered by it's radio emission, unusual low-mass binaries, gamma-ray pulsars and pulsars suitable for pulsar timing array experiments.Comment: Proceedings of IAUS 291 "Neutron Stars and Pulsars: Challenges and Opportunities after 80 years"; J. van Leeuwen (ed.); 6 pages, 2 figure

The part-frequency matrices of a partition

A new combinatorial object is introduced, the part-frequency matrix sequence of a partition, which is elementary to describe and is naturally motivated by Glaisher's bijection. We prove results that suggest surprising usefulness for such a simple tool, including the existence of a related statistic that realizes every possible Ramanujan-type congruence for the partition function. To further exhibit its research utility, we give an easy generalization of a theorem of Andrews, Dixit and Yee on the mock theta functions. Throughout, we state a number of observations and questions that can motivate an array of investigations.Comment: Presented at the Kliakhandler Conference 2015, Algebraic Combinatorics and Applications, at Michigan Technological University. To appear in the Proceeding

Proof of a conjectured q,t-Schr\"{o}der identity

A conjecture of Chunwei Song on a limiting case of the q,t-Schr\"{o}der theorem is proved combinatorially. The proof matches pairs of tableaux to Catalan words in a manner that preserves differences in the maj statistic.Comment: 8 pages; v2 corrects presentation error in example and notation (substance of proof unchanged

Partitions into a small number of part sizes

We study $\nu_k(n)$, the number of partitions of $n$ into $k$ part sizes, and find numerous arithmetic progressions where $\nu_2$ and $\nu_3$ take on values divisible by 2 and 4. Expanding earlier work, we show $\nu_2(An+B) \equiv 0 \pmod{4}$ for (A,B) = (36,30), (72,42), (252,114), (196,70), and likely many other progressions for which our method should easily generalize. Of some independent interest, we prove that the overpartition function $\bar{p}(n) \equiv 0 \pmod{16}$ in the first three progressions (the fourth is known), and thereby show that $\nu_3(An+B) \equiv 0 \pmod{2}$ in each of these progressions as well, and discuss the relationship between these congruences in more generality. We end with open questions in this area.Comment: 11 pages; v2, small correction to proof of Theorem 7; v3, clean up some explanations, acknowledge recent results from Xinhua Xiong on overpartitions mod 16; v4, final journal version to appear International Journal of Number Theory (Feb. 2017

Installation and Use of Pulsar Search Software

Searching for radio pulsars typically requires a bespoke software pipeline to efficiently make new discoveries. In this paper we describe the search process, provide a tool for installing pulsar software, and give an example of a pulsar search.Comment: Tutorial on tempo2 presented at the Beijing pulsar conference during 2011. To appear in "Astronomical Research and Technology" Vol.9, No.3, page 21

Automatic Pet Door and Magnetic Field Activation

Automatic pet doors are sold commercially as a completely built unit on today’s market. A low-cost design has been created to allow more flexible placement and construction of a door. This door is unlocked upon detection of a magnetic field originating from the pet’s collar. The required activation signal has been carefully characterized to allow customization of the door and collar for a particular purpose. Detailed information on the operating circuit and sensor activation are provided. Results of how the door is constructed and operated, as well as personalization, are presented

A Bijection for Partitions with Initial Repetitions

A theorem of Andrews equates partitions in which no part is repeated more than 2k-1 times to partitions in which, if j appears at least k times, all parts less than j also do so. This paper proves the theorem bijectively, with some of the generalizations that usually arise from such proofs.Comment: 5 page