Pattern Matching in Multiple Streams

We investigate the problem of deterministic pattern matching in multiple streams. In this model, one symbol arrives at a time and is associated with one of s streaming texts. The task at each time step is to report if there is a new match between a fixed pattern of length m and a newly updated stream. As is usual in the streaming context, the goal is to use as little space as possible while still reporting matches quickly. We give almost matching upper and lower space bounds for three distinct pattern matching problems. For exact matching we show that the problem can be solved in constant time per arriving symbol and O(m+s) words of space. For the k-mismatch and k-difference problems we give O(k) time solutions that require O(m+ks) words of space. In all three cases we also give space lower bounds which show our methods are optimal up to a single logarithmic factor. Finally we set out a number of open problems related to this new model for pattern matching.Comment: 13 pages, 1 figur

Chemical approaches to carbon dioxide utilization for manned Mars missions

Use of resources available in situ is a critical enabling technology for a permanent human presence in space. A permanent presence on Mars, e.g., requires a large infrastructure to sustain life under hostile conditions. As a resource on Mars, atmospheric CO2 is as follows: abundant; available at all points on the surface; of known presence; chemically simple; and can be obtained by simple compression. Many studies focus on obtaining O2 and the various uses for O2 including life support and fuel; discussion of CO, the coproduct from CO2 fixation revolves around its uses as a fuel, being oxidized back to CO2. Several new proposals are studied for CO2 fixation through chemical, photochemical, and photoelectrochemical means. For example, the reduction of CO2 to hydrocarbons such as acetylene (C2H2) can be accomplished with H2. C2H2 has a theoretical vacuum specific impulse of approx. 375 secs. Potential uses were also studied of CO2, as obtained or further reduced to carbon, as a reducing agent in metal oxide processing to form metals or metal carbides for use as structural or power materials; the CO2 can be recycled to generate O2 and CO

Free subgroups of one-relator relative presentations

Suppose that G is a nontrivial torsion-free group and w is a word over the alphabet G\cup\{x_1^{\pm1},...,x_n^{\pm1}\}. It is proved that for n\ge2 the group \~G= always contains a nonabelian free subgroup. For n=1 the question about the existence of nonabelian free subgroups in \~G is answered completely in the unimodular case (i.e., when the exponent sum of x_1 in w is one). Some generalisations of these results are discussed.Comment: V3: A small correction in the last phrase of the proof of Theorem 1. 4 page

Clinical norms for evaluation of accommodative facility, vergence facility and accommodative/vergence facility

The purpose of this project was to gather normative data on the performance of schoolchildren in grades one and four on the accommodative, prism, and distance rock tests. Since these tests are commonly used as screening devices to assist in diagnosing the asthenopic child, this data can be utilized when assessing and comparing a chiId\u27s performance. Another important purpose in the design of this study was to develop targets for accommodation and prism rock testing that would reduce confounding variables inherent to previously used targets. This study used modified Landolt C targets. As a result, the data has shown that there is a very active transition period of maturity and visual skill level occurring between the first and fourth grade. Clinically, these tests may be utilized to measure the maturational progress of these visual subskills enabling the clinician to make a more accurate diagnosis. The validity of directly applying normative data derived from adult popu·1ations to young children should be avoided

Infinite-dimensional Compact Quantum Semigroup

In this paper we construct a compact quantum semigroup structure on the Toeplitz algebra $\mathcal{T}$. The existence of a subalgebra, isomorphic to the algebra of regular Borel's measures on a circle with convolution product, in the dual algebra $\mathcal{T}^*$ is shown. The existence of Haar functionals in the dual algebra and in the above-mentioned subalgebra is proved. Also we show the connection between $\mathcal{T}$ and the structure of weak Hopf algebra.Comment: 17 page

Caesarean section-related blood transfusion: risk factors in a private teaching hospital in Nigeria

Background: Comprehensive emergency obstetric care, which includes the life-saving procedure of blood transfusion, is one of the essential components of effective emergency obstetric care that leads to a reduction in maternal mortality. In this study, blood transfusion risk factors were found in patients who had Caesarean deliveries at our facility.Methods: This was a retrospective study of all pregnant women who had caesarean section at Babcock University Teaching Hospital, Nigeria between 2016 and 2020. Their medical records were retrieved and reviewed using pro-forma. Chi square analysis was used to determine significant association between blood transfusion status and independent variables. Information was extracted from medical records using pro-forma.Results: Of 1568 obstetric admissions, there were 1210 deliveries and 369 (30.5%) caesarean sections. Ninety-five women (25.7%) of those that had caesarean sections were transfused. The incidence of blood transfusion was 13.7%. The preoperative packed cell volume, age and caesarean delivery type were significantly associated with blood transfusion status (p<0.05).Conclusions: Preoperative anemia, age and caesarean delivery type were all associated with blood transfusion status. To maximize hemoglobin levels at delivery and to identify high-risk patients, regular antenatal checkups should be given more importance

Investigation of methods to produce a uniform cloud of fuel particles in a flame tube

The combustion of a uniform, quiescent cloud of 30-micron fuel particles in a flame tube was proposed as a space-based, low-gravity experiment. The subject is the normal- and low-gravity testing of several methods to produce such a cloud, including telescoping propeller fans, air pumps, axial and quadrature acoustical speakers, and combinations of these devices. When operated in steady state, none of the methods produced an acceptably uniform cloud (+ or - 5 percent of the mean concentration), and voids in the cloud were clearly visible. In some cases, severe particle agglomeration was observed; however, these clusters could be broken apart by a short acoustic burst from an axially in-line speaker. Analyses and experiments reported elsewhere suggest that transient, acoustic mixing methods can enhance cloud uniformity while minimizing particle agglomeration

Energy in Agriculture: Planning a House With an Energy Future

If you are planning a new house, consider the following. Suppose the price of energy for residential space heating and domestic water heating doubles or triples during the next 10 years. Will your new house be prepared for such a future? Have you given the energy required to operate your home equal importance to building site, style, floor plans and construction materials