2,075 research outputs found
Surface conditions of the Orgueil meteorite parent body as indicated by mineral associations
Three periods of mineral formation from study of Orgueil meteorit
A chondrule in the Chainpur meteorite
Glass occurrence in chondrules as evidence for formation by rapid cooling of liquid droplets - chondritic meteorite
Investigation of the fine structure in the 2 D sequence of sodium using level-crossing spectroscopy
Splittings in the n 2 D sequence were measured for n=4-9. An accuracy of about 0.1% was obtained in level-crossing measurements on an atomic beam. The D states were populated by step-wise excitation, using an RF lamp and a CW dye laser. A method for measuring the sign of the spin-orbit coupling constant is demonstrated. With the present measurements, the highly anomalous n 2 D sequence in sodium has now been studied for n=3-16
A mobile system for active otpical pollution monitoring
The remote monitoring of atmospheric pollutants can now be performed in several ways. Laser radar techniques have proven their ability to reveal the spatial distribution of different species or particles. Classical optical techniques can also be used, but yield the average concentration over a given path and hence no range resolution. One such technique is Differential Optical Absorption Spectroscopy, DOAS. Such schemes can be used to monitor paths that a preliminary lidar investigation has shown to be of interest. Having previously had access to a mobile lidar system, a new system has been completed. The construction builds on experience from using the other system and it is meant to be more of a mobile optical laboratory than just a lidar system. A complete system description is given along with some preliminary usage. Future uses are contemplated
Fast Searching in Packed Strings
Given strings and the (exact) string matching problem is to find all
positions of substrings in matching . The classical Knuth-Morris-Pratt
algorithm [SIAM J. Comput., 1977] solves the string matching problem in linear
time which is optimal if we can only read one character at the time. However,
most strings are stored in a computer in a packed representation with several
characters in a single word, giving us the opportunity to read multiple
characters simultaneously. In this paper we study the worst-case complexity of
string matching on strings given in packed representation. Let be
the lengths and , respectively, and let denote the size of the
alphabet. On a standard unit-cost word-RAM with logarithmic word size we
present an algorithm using time O\left(\frac{n}{\log_\sigma n} + m +
\occ\right). Here \occ is the number of occurrences of in . For this improves the bound of the Knuth-Morris-Pratt algorithm.
Furthermore, if our algorithm is optimal since any
algorithm must spend at least \Omega(\frac{(n+m)\log
\sigma}{\log n} + \occ) = \Omega(\frac{n}{\log_\sigma n} + \occ) time to
read the input and report all occurrences. The result is obtained by a novel
automaton construction based on the Knuth-Morris-Pratt algorithm combined with
a new compact representation of subautomata allowing an optimal
tabulation-based simulation.Comment: To appear in Journal of Discrete Algorithms. Special Issue on CPM
200
Compliance in own-check systems poses challenges in small-scale slaughterhouses
Small-scale slaughterhouses (SHs) face many challenges, not least due to the requirements of food safety legislation. Food business operators' (FBOs') own-check system is very important for food safety, but its proper implementation can be quite difficult and laborious for small-scale SHs. In the European Union, the importance not only of food safety but also facilitation of local food production, including small-scale slaughtering, is highlighted. The aim of our study was to assess compliance with legislation of own-check systems, including six own-check programmes and HACCP, in small-scale SHs. The FBOs' opinions of the implementation of own-check systems were also sought to elucidate possible obstacles in implementation. Our results showed that the best compliance in own-check programmes was achieved in temperature of storage rooms and traceability. FBOs also evaluated these programmes as necessary. However, FBOs' perceived necessity of own-check programmes did not always lead to compliance, as was the case with labelling and HACCP. Instead, in HACCP laboriousness and compliance showed a negative correlation (p <0.05). In addition to laboriousness, costs of own-check programmes, specifically concerning microbiological sampling requirements, appeared to influence compliance, with many of the small-scale SHs poorly following sampling requirements. FBOs also noted the high costs of the non-edible by-product programme. Moreover, the results show that official veterinarians' assessment of compliance was significantly higher than that of the researcher, which warrants further investigation. This study reveals that many small-scale SHs in Finland struggle with food safety requirements. Amendments of some of the requirements to ease the burden of FBOs are proposed. HACCP in particular is suggested to be simplified. In addition, ways to improve food safety and official control in small-scale SHs are discussed.Peer reviewe
The Chandrasekhar limit for quark stars
The Chandrasekhar limit for quark stars is evaluated from simple energy
balance relations, as proposed by Landau for white dwarfs or neutron stars. It
has been found that the limit for quark stars depends on, in addition to the
fundamental constants, the Bag constant.Comment: LateX fil
Average-Case Optimal Approximate Circular String Matching
Approximate string matching is the problem of finding all factors of a text t
of length n that are at a distance at most k from a pattern x of length m.
Approximate circular string matching is the problem of finding all factors of t
that are at a distance at most k from x or from any of its rotations. In this
article, we present a new algorithm for approximate circular string matching
under the edit distance model with optimal average-case search time O(n(k + log
m)/m). Optimal average-case search time can also be achieved by the algorithms
for multiple approximate string matching (Fredriksson and Navarro, 2004) using
x and its rotations as the set of multiple patterns. Here we reduce the
preprocessing time and space requirements compared to that approach
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