Visual Search for Galaxies near the Northern Crossing of the Supergalactic plane by the Milky Way

We have visually examined twelve Palomar red Plates for galaxies at low Galactic latitude b, where the Supergalactic Plane (SGP) is crossed by the Galactic Plane (GP), at Galactic longitude l ~135 degrees. The catalogue consists of 2575 galaxy candidates, of which 462 have major axis diameters d >= 0.8 arc min (uncorrected for extinction). Galaxy candidates can be identified down to |b| ~ 0 degrees. One of our galaxy candidates (J24 = Dwingeloo 1) has recently been discovered independently in 21cm by Kraan-Korteweg et al. (1994) as a nearby galaxy. Comparisons with the structures seen in the IRAS and UGC catalogues are made. We compare the success rate of identifying galaxies using the IRAS Point Source Catalogue under different colour selection criteria. The criteria that require both the 60 micron and 100 micron fluxes to be of high quality, have the highest probability of selecting a galaxy (with d >= 0.6 arc min), but at the expense of selecting a smaller number of galaxies in total.Comment: uuencoded compressed postscript, without figures. The figures are available at http://www.ast.cam.ac.uk/preprint/PrePrint.htm

Congestion charging mechanisms for roads : an evaluation of current practice

The author explores 20 criteria for a good road pricing system and presents case studies illustrating the costs, revenues, and benefits of alternative congestion charging mechanisms. The author finds that manual tollbooths are not suitable for congestion charging because they are land-, labor-, and time-intensive. Cordon pricing (as in the Bergen toll ring) can be an effective instrument for charging for congestion if half the toll lanes are reserved for seasonal pass holders traveling through the pricing points at regular highway speed. Enforcement of those driving in reserved lanes can be carried out by periodic videographs of vehicle license plates. Area licensing schemes require that vehicles entering the central business district during peak hours prominently display a monthly or daily license. Enforcement is undertaken at gantry points by traffic wardens who perform visual checks on the nonstop traffic. The enforcement costs of area licensing schemes are prohibitive at motorway speeds but relatively low-cost in a standard congested urban setting with limited gateways. Area licensing schemes, also known as supplementary licensing, carry the lowest cost per transaction. Electronic road pricing with automatic vehicle identification (an off-vehicle recording system) is electronic toll collection by time of day writ large and made obligatory on vehicle owners in a jurisdiction. The cost of the electronic equipment is not trivial, but is outweighed by the benefits. Sensitivity analysis performed on the Hong Kong electronic road pricing scheme in 1983-85 shows that even after excluding time savings, the savings in operating costs produce benefit figures that are greater than system costs. The invasion-of-privacy issues that led to the political failure of the Hong Kong electronic road pricing scheme can not be overcome by giving road users access to confidential numbered account arrangements with a prepaid cash deposit. The capital cost of electronic road pricing with smart card technology (an on-vehicle charging system) is higher than the cost for automatic vehicle identification technology alone, but benefits still outweigh costs (as in the Dutch proposal). Together, the benefit-cost ratio and the cost per transaction are acceptable but this technology is still not widely used commercially. The author argues that electronic approaches to direct road use charging are superior to manual approaches for road users, road authorities, and society as a whole. And rapid progress in microelectronics, cryptology, and microwave technologies will continue to yield large-scale economies in the manufacturing of automatic vehicle identification equipment, read-write transponders, smart cards, and the hardware and software that go with them. The author ranks electronic road pricing with automatic vehicle identification alone higher than electronic road pricing with smart card-type AVI based on an unweighted index of all criteria. And generally, the area licensing scheme is superior to cordon pricing. If budgets allow, authorities should investigate the feasibility of electronic road pricing. If the budget is tight, they should look into the area licensing scheme with its low cost and high benefit-cost ratio (the latter being the most important of the 20 criteria the author uses). Both conceptually and practically, the author finds that it is important to earmark the proceeds of road pricing to implement marginal cost pricing in the road sector.Roads&Highways,Public Sector Economics&Finance,Banks&Banking Reform,Urban Transport,Municipal Financial Management

The puzzlingly large Ca II triplet absorption in dwarf elliptical galaxies

We present central CaT, PaT, and CaT* indices for a sample of fifteen dwarf elliptical galaxies (dEs). Twelve of these have CaT* ~ 7 A and extend the negative correlation between the CaT* index and central velocity dispersion sigma, which was derived for bright ellipticals (Es), down to 20 < sigma < 55 km/s. For five dEs we have independent age and metallicity estimates. Four of these have CaT* ~ 7 A, much higher than expected from their low metallicities (-1.5 < [Z/H] < -0.5). The observed anti-correlation of CaT* as a function of sigma or Z is in flagrant disagreement with theory. We discuss some of the amendments that have been proposed to bring the theoretical predictions into agreement with the observed CaT*-values of bright Es and how they can be extended to incorporate also the observed CaT*-values of dEs. Moreover, 3 dEs in our sample have CaT* ~ 5 A, as would be expected for metal-poor stellar systems. Any theory for dE evolution will have to be able to explain the co-existence of low-CaT* and high-CaT* dEs at a given mean metallicity. This could be the first direct evidence that the dE population is not homogeneous, and that different evolutionary paths led to morphologically and kinematically similar but chemically distinct objects.Comment: 4 pages, 3 figures, accepted for publication in ApJ Letter

A short note on the joint entropy of n/2-wise independence

In this note, we prove a tight lower bound on the joint entropy of $n$ unbiased Bernoulli random variables which are $n/2$-wise independent. For general $k$-wise independence, we give new lower bounds by adapting Navon and Samorodnitsky's Fourier proof of the `LP bound' on error correcting codes. This counts as partial progress on a problem asked by Gavinsky and Pudl\'ak.Comment: 6 pages, some errors fixe

Float zone experiments in space

The molten zone/freezing crystal interface system and all the mechanisms were examined. If Marangoni convection produces oscillatory flows in the float zone of semiconductor materials, such as silicon, then it is unlikely that superior quality crystals can be grown in space using this process. The major goals were: (1) to determine the conditions for the onset of Marangoni flows in molten tin, a model system for low Prandtl number molten semiconductor materials; (2) to determine whether the flows can be suppressed by a thin oxide layer; and (3) based on experimental and mathematical analysis, to predict whether oscillatory flows will occur in the float zone silicon geometry in space, and if so, could it be suppressed by thin oxide or nitride films. Techniques were developed to analyze molten tin surfaces in a UHV system in a disk float zone geometry to minimize buoyancy flows. The critical Marangoni number for onset of oscillatory flows was determined to be greater than 4300 on atomically clean molten tin surfaces

Sialylated glycans as receptor and inhibitor of enterovirus 71 infection to DLD-1 intestinal cells

<p>Abstract</p> <p>Background</p> <p>Many viruses recognize specific sugar residues, particularly sulfated or sialylated glycans, as the infection receptors. A change of sialic acid (2-6)-linked galactose (SA-α2,6Gal) to SA-α2,3Gal determines the receptor for avian flu infection. The receptor for enterovirus 71 (EV71) infection that frequently causes fatal encephalitis in Asian children remains unclear. Currently, there is no effective vaccine or anti-virus agent for EV71 infection. Using DLD-1 intestinal cells, this study investigated whether SA-linked glycan on DLD-1 intestinal cells was a receptor for EV71, and whether natural SA-linked sugars from human milk could block EV71 infection.</p> <p>Results</p> <p>EV71 specifically infected DLD-1 intestinal cells but not K562 myeloid cells. Depletion of O-linked glycans or glycolipids, but not N-linked glycans, significantly decreased EV71 infection of DLD-1 cells. Pretreatment of DLD-1 cells with sialidase (10 mU, 2 hours) significantly reduced 20-fold EV71 replication (p < 0.01). Taken together, these results suggest that SA-linked O-glycans and glycolipids, but not N-glycans, on DLD-1 cells were responsible for EV71 infection. Purified SA-α2,3Gal and SA-α2,6Gal from human milk significantly inhibited EV71 infection of DLD-1 cells, indicating terminal SA-linked glycans could be receptors and inhibitors of EV71 infection.</p> <p>Conclusion</p> <p>This is the first in the literature to demonstrate that EV71 uses SA-linked glycans as receptors for infection, and natural SA-linked glycans from human milk can protect intestinal cells from EV71 infection. Further studies will test how a SA-containing glycan can prevent EV71 in the future.</p

Kajian Pengembangan dan Pemanfaatan Tanaman Pakan Leguminosa Mendukung Peningkatan Produksi Ternak Sapi di Nusa Tenggara Timur

Leguminosa mempunyai berbagai macam manfaat, diantaranya untuk menyuburkan tanah dan sumber pakan ternak. Sebagai pakan ternak leguminosa mempunyai kualitas tinggi dan tersedia sepanjang tahun. Oleh karena itu, pengembangannya sebagai tanaman pakan sangat diperlukan. Tujuan penulisan ini adalah untuk melihat perkembangan pemanfaatan TPT sebagai sumber pakan sapi. Kajian pengembangan dan pemanfaatan tanaman pakan leguminosa di Nusa Tenggara Timur telah dilakukan di tingkat petani dari tahun 2006-2017 bagi leguminosa herba dan dari tahun 2012-2016 bagi leguminosa pohon Leucaena leucocephala cv Tarramba, dengan melibatkan berbagai stakeholder. Tulisan ini me-review berbagai capaian penting yang telah dipublikasikan dan yang masih dicatat saat ini dengan cara on farm record keeping, dijelaskan dan dibahas secara deskriptif

Enhancing capacity of coherent optical information storage and transfer in a Bose-Einstein condensate

Coherent optical information storage capacity of an atomic Bose-Einstein condensate is examined. Theory of slow light propagation in atomic clouds is generalized to short pulse regime by taking into account group velocity dispersion. It is shown that the number of stored pulses in the condensate can be optimized for a particular coupling laser power, temperature and interatomic interaction strength. Analytical results are derived for semi-ideal model of the condensate using effective uniform density zone approximation. Detailed numerical simulations are also performed. It is found that axial density profile of the condensate protects the pulse against the group velocity dispersion. Furthermore, taking into account finite radial size of the condensate, multi-mode light propagation in atomic Bose-Einstein condensate is investigated. The number of modes that can be supported by a condensate is found. Single mode condition is determined as a function of experimentally accessible parameters including trap size, temperature, condensate number density and scattering length. Quantum coherent atom-light interaction schemes are proposed for enhancing multi-mode light propagation effects.Comment: 12pages. Laser Physics, in pres