On Languages Accepted by P/T Systems Composed of joins

Recently, some studies linked the computational power of abstract computing systems based on multiset rewriting to models of Petri nets and the computation power of these nets to their topology. In turn, the computational power of these abstract computing devices can be understood by just looking at their topology, that is, information flow. Here we continue this line of research introducing J languages and proving that they can be accepted by place/transition systems whose underlying net is composed only of joins. Moreover, we investigate how J languages relate to other families of formal languages. In particular, we show that every J language can be accepted by a log n space-bounded non-deterministic Turing machine with a one-way read-only input. We also show that every J language has a semilinear Parikh map and that J languages and context-free languages (CFLs) are incomparable

Growth Performance of Hill Dipterocarp Forests Five Years after Harvesting at the Angsi Forest Reserve, Negeri Sembilan, Malaysia, 2007

The future long-term timber supply from sustainably managed forest in Peninsular Malaysia is largely dependent on the availability of timber from the productive Permanent Forest Estate (PFE) especially from the Hill Dipterocarp Forests. Future log supply also will come from the second and successive harvest in logged-over forest. Specific information on behaviours of particular forest stand pertaining to growth performance, mortality, density, structure and species composition is required to evaluate the management systems and its suitability under different forests types. The study was conducted in a logged over Hill Dipterocarps Forest in Angsi Forest Reserve, Negeri Sembilan with the objective to evaluate the growth response five years after harvesting. The data consist of five annual measurements (2000-05) collected from four I-ha permanent sample plots. The data were analysed in terms of diameter increments, basal areas, tree volumes and also growth projection using existing growth and yield model. The results show pattern and trend of tree growth five years after logging. The stocking of trees, basal area and volume for both trees over 5 and 30 cm dbh were significantly -different ( ~ ~ 0 . 0 5a)m ong plots, species groups and measurement years. The ANOVA also showed that the interaction between species groups, study plots and measurement years were also significant (~~0.05). Stocking of trees for both over 5 and 30 cm dbh showed an increment over the measurement period. However, the overall increment rates of all trees over 30 cm dbh were relatively low, when compared to the rates assumed under the Selective Management System (SMS). The overall diameter periodic annual increment (DPAI) of 0.65 cm tree-' yr-' for all trees over 30 cm dbh is considerably lower than the rate of 0.8 to 1.0 cm tree-' yr-' assumed under the SMS. Although the DPAI of the dipterocarps was higher than the non-dipterocarps, their overall contributions to forest growth was small due to their lower stocking in the residual stand. The overall mean annual mortality (3.51%) of all trees over 30 cm dbh for 5-year period was higher than that assumed under the SMS (0.9%). Based on these growth rates, anticipating a second cut in 25 to 30 years as stipulated under SMS, would not be applicable for this area. Therefore, future research on behaviour of the forest should be conducted. Based on projection of growth and yield model until year 60 indicates that growth in timber, basal area and the number of stems per hectare is increasing each period until end of the projection period (year 60) at slower state. This shows that the study areas will experience long growth period due to high density of trees in lower diameter class

American grail: Contemporary federal budget reform

Federal budget reforms initiated by the executive branch of government have been unsustainable. A commonality of these failed reforms is that they lack the support of Congress. The objective of this research is to determine whether the Program Assessment Rating Tool (PART), the most recent executive-initiated budget reform, was supported by Congress. The scope of this research includes an exploration of historic budget reforms, initiated from 1921 through 2008, to provide insight into previous reform sustainability.;Budget reforms provide context from which to view the power struggle between the executive and legislative branches of government; the tension of separate institutions sharing power. This research also offers insight into the extent that the U.S. separation of powers structure interferes with the implementation of government-wide performance measurement systems at the federal level.;Using data obtained from congressional committee hearings this research finds little congressional interest in PART; legislators were primarily indifferent to this executive tool. Generalizing congressional PART sentiment, results indicate that legislators with more business experience are more likely to be supportive of budget reforms making them important stakeholders to include in the next effort at reforming the budget process. Legislators with greater seniority and those who receive more campaign contributions from political action committee are more likely to resist reform.;The research demonstrates that reforms that are the product of cooperation between both executive and legislative branches are more likely to be sustained; legislating budget reforms is key to sustained executive-initiated reforms. In addition, analyses of historic budget reforms show that the legislature has been the driver of budget reforms, not the executive

Evaluation of thin wall spacecraft electrical wiring. Volume II - Test results and facilities Technical report no. 1

Insulation resistance of spacecraft wiring against abrasion, radiation effects, oxygen environment, and extrusion lubricant

Evaluation of thin wall spacecraft electrical wiring. Volume II - Summary and conclusions Final report

Performance characteristics environmentally determined for spacecraft, thin wall wiring - summary and conclusion

Evaluation of thin wall spacecraft electrical wiring. Volume I - Test methods and facilities Technical report no. 1

Test methods and facilities used in evaluating performance characteristics of thin wall spacecraft electric wiring under simulated spacecraft environment

How Can Art Educators Promote A Choice-Based Program While Supporting And Maintaining Standards-Based Instruction And Assessment?

In order for art educators to uphold best practices, we must recognize the shifting and overlapping philosophies in the art education world. We must reflect and adjust to the needs of our students and communities, as well as embrace the research and practices of previous scholars and art educators to help us grow in our own practice. The guiding question to address this challenge was: “How can art educators promote a choice-based program while supporting and maintaining standards-based instruction and assessment?” The literature review includes an examination of standards based instruction, 21st century learning, Teaching for Artistic Behavior, choice based teaching, Studio Habits of Mind and growth mindset. The intent of this research was to combine the above best practices in order to support the idea of a true choice-based classroom. A Google Site was created, as well as three different types of assessments, to measure learning objectives in a Choice-Based Ceramics classroom

P Systems and Topology: Some Suggestions for Research

Lately, some studies linked the computational power of abstract computing systems based on multiset rewriting to Petri nets and the computation power of these nets to their topology. In turn, the computational power of these abstract computing devices can be understood just looking at their topology, that is, information flow. This line of research is very promising for several aspects: its results are valid for a broad range of systems based on multiset rewriting; it allows to know the computational power of abstract computing devices without tedious proofs based on simulations; it links computational power to topology and, in this way, it opens a broad range of questions. In this note we summarize the known result on this topic and we list a few suggestions for research together with the relevance of possible outcomes

Coherence-length effects in fast atom diffraction at grazing incidence

Coherence properties of projectiles, found relevant in ion-atom collisions, are investigated by analyzing the influence of the degree of coherence of the atomic beam on interference patterns produced by grazing-incidence fast-atom diffraction (GIFAD or FAD). The transverse coherence length of the projectiles, which depends on the incidence conditions and the collimating setup, determines the overall characteristics of GIFAD distributions. We show that for atoms scattered from a LiF(001) surface after a given collimation, we can modify the interference signatures of the angular spectra by varying the total impact energy, while keeping the normal energy as a constant. Also, the role played by the geometry of the collimating aperture is analyzed, comparing results for square and circular openings. Furthermore, we study the spot-beam effect, which is due to different focus points of the impinging particles. We show that when a region narrower than a single crystallographic channel is coherently illuminated by the atomic beam, the spot-beam contribution strongly affects the visibility of the interference structures, contributing to the gradual quantum-classical transition of the projectile distributions.Fil: Gravielle, Maria Silvia. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Miraglia, Jorge Esteban. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Frisco, Leandro. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentin

The effects of trehalose and other solutions on cellular recovery from cotton swabs for forensic purposes

Recovering deoxyribose nucleic acid (DNA) from items of evidence can provide critical information in criminal cases. Since the development of the polymerase chain reaction (PCR) and use of short tandem repeats (STR) to create unique profiles from an individual’s genome1, sampling items of evidence for the presence of DNA has become routine. Biological evidentiary specimens are commonly collected at crime scenes as well as sampled from collected items of interest by using a cotton swab which can then be easily stored and tested as needed. However, even with modern advances in technology and methods, large amounts of DNA can be either lost throughout processing or remain on the substrate used for collection of the sample, such as a cotton swab2. While many of the downstream processes of evidence evaluation have been vastly improved through the use of automated procedures, engineered buffers, and commercially available extraction kits, the front-end procedures are typically more technician dependent; it is an area in which opportunities to fine-tune techniques remain. The most recent change to generalized stain recovery occurred after Sweet et al. achieved an increased efficiency of recovery by using what they referred to as the “double swab technique”. The classic method of collection before this time used a single, wet cotton swab. Based on a need to increase the effective collection of DNA from saliva samples, the double swab method was developed. The classic method was modified by using a second, dry swab to collect remaining moisture deposited by the first, wet swab3. To continue the effort to maximize cellular and DNA recovery from cotton swabs the use of trehalose in the cotton swab wetting solution was explored. D-(+)-Trehalose dihydrate is a naturally occurring disaccharide composed of two alpha glucose molecules. An alpha, alpha-1, 1 bond connects the two molecules which lends high resistance to acid hydrolysis, giving the molecule unique properties. Specifically, these properties allow the compound to maintain stability even during exposure to high temperatures and in acidic conditions4,5. In nature, trehalose can be found in plants and small organisms where it is thought to act as a protectant against fluctuations in moisture and temperature. Synthesis and release of trehalose by lower life forms during stressed states shows protective properties to cellular integrity by inhibiting protein denaturation6. The objectives of this study are to investigate the use of trehalose as an additive in DNA collection processes. The experiments examine the ability of trehalose to increase efficiency of cellular release from cotton swabs during the elution step and compares trehalose to other common buffer additives, bovine serum albumin (BSA) and sodium dodecyl sulfate (SDS), when utilized as a pre-treatment or moistening agent on the cotton swab. Two procedures were developed to test the ability of trehalose to increase efficiency of cellular and DNA release from cotton swabs. The first procedure tested trehalose at 0.2 molar (M) and 1 M concentrations as the incubating solution over1 hour and 18 hour time periods after which the cotton swab was eluted using a spin-x insert and centrifugation. Both eluate and cotton swab were then processed using ZyGEM direct lysis and quantified. Quantification results of the eluate and swabs incubated in trehalose solution were not significantly different from controls. However, it is apparent that a large portion of deposited DNA remained on the swabs even after elution and ZyGEM direct lysis. The second procedure tested trehalose against BSA and SDS as treatments to cotton swabs before DNA collection. A pre-treated group (solution was applied to the swab and dried overnight; DNA was deposited to the dried swab) and a moist group (solution was applied and DNA deposited immediately) were tested after deposition of a set volume of saliva cell suspension. Quantification and amplification results of SDS treated samples indicated significant differences of DNA recovery and average peak height of profiles compared to water and buffer controls. Trehalose samples did have some significant improvement in DNA yield; however, the addition of trehalose as a moistening agent for cotton swabs does not prove to be of forensic value