Deer mandible tools: an examination of Oneota modified mandibles from La Crosse County, Wisconsin

This study focuses on the modified deer mandibles that have been recovered at late prehistoric Oneota sites over the last few decades by the M.V.A.C. in La Crosse County, Wisconsin. The purpose of this study is to clarify through experimentation the function of Oneota tools made from deer mandibles. Of the numerous deer mandibles and deer mandible fragments that have been recovered from Oneota context in the La Crosse locality there are a set of five deer mandibles, which show signs of heavy wear along the fracture of the bone marrow cavity where they were broken, presumably to obtain the marrow. These artifacts were found at the Pammel Creek site (47Lc61), the Valley View site (47Lc34), and the Gundersen Lutheran site (47Lc394), and the Sand Lake site (47Lc44). Experimental use demonstrated that the Oneota mandibles were identified as hide scrapers, which were used to soften leather for hide working

The Extended Jet In AP Librae As The Source Of The VHE γ\gamma-ray Emission

Most modeling attempts of blazars use a small emission zone located close to the central black hole in order to explain the broad-band spectral energy distribution. Here we present a case where additionally to the small region a $>$kpc-scale jet is required to successfully reproduce the spectrum and especially the TeV emission, namely the low-frequeny peaked BL Lac object AP Librae detected in the TeV domain by the H.E.S.S. experiment. Given that other parts of the spectral energy distribution follow the characteristics implied by the source classification, the inverse Compton component spans 10 orders of magnitude, which cannot be reproduced by the one-zone model. Additionally, observational constraints in both the synchrotron and inverse Compton compoenent strongly constrain the parameters of a self-consistent model ruling out the possibility of TeV photon production in the vicinity of the galactic center. We discuss the possibility that the TeV radiation is emitted by highly energetic particles in the extended, arcsec-scale jet, which has been detected at radio and X-ray energies. The slope of the jet X-ray spectrum indicates an inverse Compton origin, and an extrapolation to higher energies coincides with a break feature in the $\gamma$-ray band. Modeling the jet emission with inverse Compton scattering of the cosmic microwave background results in an excellent fit of the radio, X-ray and TeV emission. Implications will be discussed, such as properties of the jet, acceleration scenarios, and observations to test the model. If confirmed, large scale jets are able to efficiently accelerate particles and to keep relativistic speeds up to distances of several 100kpc.Comment: 5 pages, 1 figure, to appear in the AIP Conference proceedings of the "High Energy Gamma-Ray Astronomy (Gamma2016)", edited by F. Aharonian, W. Hofmann, F. Riege

PotLLL: A Polynomial Time Version of LLL With Deep Insertions

Lattice reduction algorithms have numerous applications in number theory, algebra, as well as in cryptanalysis. The most famous algorithm for lattice reduction is the LLL algorithm. In polynomial time it computes a reduced basis with provable output quality. One early improvement of the LLL algorithm was LLL with deep insertions (DeepLLL). The output of this version of LLL has higher quality in practice but the running time seems to explode. Weaker variants of DeepLLL, where the insertions are restricted to blocks, behave nicely in practice concerning the running time. However no proof of polynomial running time is known. In this paper PotLLL, a new variant of DeepLLL with provably polynomial running time, is presented. We compare the practical behavior of the new algorithm to classical LLL, BKZ as well as blockwise variants of DeepLLL regarding both the output quality and running time.Comment: 17 pages, 8 figures; extended version of arXiv:1212.5100 [cs.CR

Towards Resistance Sparsifiers

We study resistance sparsification of graphs, in which the goal is to find a sparse subgraph (with reweighted edges) that approximately preserves the effective resistances between every pair of nodes. We show that every dense regular expander admits a $(1+\epsilon)$-resistance sparsifier of size $\tilde O(n/\epsilon)$, and conjecture this bound holds for all graphs on $n$ nodes. In comparison, spectral sparsification is a strictly stronger notion and requires $\Omega(n/\epsilon^2)$ edges even on the complete graph. Our approach leads to the following structural question on graphs: Does every dense regular expander contain a sparse regular expander as a subgraph? Our main technical contribution, which may of independent interest, is a positive answer to this question in a certain setting of parameters. Combining this with a recent result of von Luxburg, Radl, and Hein~(JMLR, 2014) leads to the aforementioned resistance sparsifiers

True and False Foodplants of \u3ci\u3eCallosamia Promethea\u3c/i\u3e (Lepidoptera: Saturniidae) in Southern Michigan

A survey in 1980 of the associations of over 400 cocoons of Callosamia promethea Drury in vegetation along and adjacent to southern Michigan roadsides gave evidence for seven species of true larval foodplants (not including two others known in the area from other studies) and 17 species of false foodplants, the latter determined by the (1) rarity of their association with cocoons, (2) only one or two cocoons per plant, and (3) their proximity to a well known true foodplant. Three species, sassafras, black cherry, and buttonbush, are evidently the most important true foodplants in this area. Comparisons are made of the foodplants in terms of past literature, geography, and taxonomic relationships

Attenuation of TeV γ\gamma-rays by the starlight photon field of the host galaxy

The absorption of TeV $\gamma$-ray photons produced in relativistic jets by surrounding soft photon fields is a long-standing problem of jet physics. In some cases the most likely emission site close to the central black hole is ruled out because of the high opacity caused by strong optical and infrared photon sources, such as the broad line region. Mostly neglected for jet modeling is the absorption of $\gamma$-rays in the starlight photon field of the host galaxy. Analyzing the absorption for arbitrary locations and observation angles of the $\gamma$-ray emission site within the host galaxy we find that the distance to the galaxy center, the observation angle, and the distribution of starlight in the galaxy are crucial for the amount of absorption. We derive the absorption value for a sample of $20$ TeV detected blazars with a redshift $z_r<0.2$. The absorption value of the $\gamma$-ray emission located in the galaxy center may be as high as $20\%$ with an average value of $6\%$. This is important in order to determine the intrinsic blazar parameters. We see no significant trends in our sample between the degree of absorption and host properties, such as starlight emissivity, galactic size, half-light radius, and redshift. While the uncertainty of the spectral properties of the extragalactic background light exceeds the effect of absorption by stellar light from the host galaxy in distant objects, the latter is a dominant effect in nearby sources. It may also be revealed in a differential comparison of sources with similar redshifts.Comment: 9 pages, 4 figures; accepted for publication in MNRA