On computing fixpoints in well-structured regular model checking, with applications to lossy channel systems

We prove a general finite convergence theorem for "upward-guarded" fixpoint expressions over a well-quasi-ordered set. This has immediate applications in regular model checking of well-structured systems, where a main issue is the eventual convergence of fixpoint computations. In particular, we are able to directly obtain several new decidability results on lossy channel systems.Comment: 16 page

Parameterized Verification of Graph Transformation Systems with Whole Neighbourhood Operations

We introduce a new class of graph transformation systems in which rewrite rules can be guarded by universally quantified conditions on the neighbourhood of nodes. These conditions are defined via special graph patterns which may be transformed by the rule as well. For the new class for graph rewrite rules, we provide a symbolic procedure working on minimal representations of upward closed sets of configurations. We prove correctness and effectiveness of the procedure by a categorical presentation of rewrite rules as well as the involved order, and using results for well-structured transition systems. We apply the resulting procedure to the analysis of the Distributed Dining Philosophers protocol on an arbitrary network structure.Comment: Extended version of a submittion accepted at RP'14 Worksho

Optimization of DNA Extraction of Lactobacillus spp for Identification by tuf B gene –Based Polymerase Chain Reaction

Lactobacilli are of considerable technological and commercial importance because of their role in the manufacturing and preservation of many fermented food products. The aim of this study was to optimize and evaluate three methods of DNA extraction and purification of DNA from Lactobacillus spp to be used for the amplification of 584-bp region of the tuf gene by polymerase chain reaction. The methods were: Phenol–chloroform extraction, boiling, and Wizard genomic DNA purification kit with modifications. Results demonstrated that extracted genomic DNA using Wizard genomic DNA purification kit with modifications for DNA extraction  provided  was higher yield of DNA with the highest purity than the other extraction methods. Purity was documented by gel electrophoresis. The quality of the genomic DNA isolated by this method was verified by polymerase chain reaction targeting the tuf gene. Keywords: Lactobacillus, DNA extraction,  identification, tuf gene, PCR

Zika Virus

Zika virus infection, a mosquito-borne flavivirus that causes febrile illness associated with rash, has been rapidly emerging in the Western Hemisphere over the past few months. The virus was rarely identified until outbreaks occurred on Yap Island in the Federated States of Micronesia in 2007, Fresh Polynesia in 2013, and Easter Island in 2014 (Chen & Hamer, 2016). The virus was initially detected in Brazil in 2015, in the northeast, and was subsequently identified in other states and several South American countries, including Colombia, Ecuador, Suriname, Venezuela, French Guyana, and Paraguay. Local transmission has been documented in Central America in countries such as Panama, El Salvador, Honduras, and Guatemala and in the Caribbean countries of Martinique, Puerto Rico, Dominican Republic, Haiti and Mexico (Chen & Hamer, 2016). Transmission of the virus has also been detected in travelers returning from infected regions to nonendemic countries, including United States, Canada, Japan, and Western Europe (Chen & Hamer, 2016). As of between January 01, 2015 to June 29, 2016 in the United State States there were no locally acquired mosquito-borne cases reported , with 934 travel- associated cases , 1 laboratory acquired case to a total of 935 cases. This included 13 sexual transmitted and 4 Guillain- Barre syndrome cases. With United State territories reporting 2,020 locally acquired cases, 6 travel- associated cases and 10 Guillain- Barre syndrome cases (CDC, 2016)

Consolidating Digital Partnerships between Academic Libraries in the Middle East and North Africa: A Prospective Study

The study aims to discuss the issues of strengthening digital relations between the academic libraries in the MENA and the related issues to the Open access sources, shared databases, sharing intellectual property, and activation of collaboration agendas between MENA academic libraries, by international standards. Also, to review the available partnerships among academic libraries in the Middle East and North Africa, which was the result of the libraries transformation to the digital age. The new role for academic libraries required how joining digital information resources can allow each of the contributing partners to reach new local and worldwide users (Courtney, 2009). There are several forms of academic libraries such as interactive lending, cooperative supply projects, central indexing, union catalogue, reference services, cooperative storage projects, regional cooperation in the field of computers and equipment and exchange of experiences. The current study efforts to highlight review and analyze these partnership issues

Some Determinants of Student Performance in Principles of Financial Accounting (II) – Further Evidence from Kuwait

The purpose of this study was to perform an empirical investigation of the influence of select factors on the academic performance of students studying Principles of Financial Accounting (II). This study attempts to fill some of the gaps in the existing local and regional accounting education literature and to provide comparative evidence for the harmonization of international accounting education. A stepwise regression model using a sample of 205 students from the College of Business Studies, one of the tributaries of accounting education in Kuwait, was used to test the study’s hypotheses. The results indicate that the influences of the selected factors are diverse in their effects on student performance. The prerequisite grade had the most significant influence on student performance, followed by student GPA, time-lag (the time elapsed between studying the two parts of Principles of Financial Accounting), and finally college experience. Student gender, age, and major showed no significant influence on student performance. The study concludes by considering the implications of these findings for the administration of the College of Business Studies and similar institutions, and suggests avenues for future research

Micropropagation techniques as tools for studying plant growth, tuberization and sprouting of potatoes

1988 Fall.Covers not scanned.Includes bibliographical references.Several investigations were undertaken to determine if micropropagated potato cultivars of different maturity classes performed under field conditions in a manner similar to that reported for seed tuber propagated plants of the same cultivars. Plant growth analysis was carried out with special emphasis using Richards' function for evaluating growth attributes such as plant height, leaf area, and derived growth quantities such as RGR. Early, medium, and late maturing potato cultivars were grown under field, greenhouse and vitro conditions to measure tuber yields. Two sprouting indices (sprouting rate index, and sprouting ratio index) were developed and used to quantify the sprouting characteristics of field, greenhouse, and in vitro produced tubers. Storage temperatures were 5, 10, and 20° C. The combined field data of 1986 and 1987 indicated that plant growth, development and tuber yield were in general agreement to that of seed tuber propagated plants. The derived growth quantities (i.e. RSER, RLAER, RTGR, and RUGR) provided a useful way of comparing cultivar response and explained how the overall growth and development can be understood. Significant correlations were reported between selected yield characteristics of field grown, greenhouse grown and in vitro produced tubers. Both Kennebec and Spunta had the highest yield under field, greenhouse, and in vitro conditions. Russet Burbank and Norland had the lowest yield while Desiree and Norgold Russet had an intermediate response. Both sprouting indices incorporate the influence of factors such as cultivar, temperature and tuber size. Both indices also indicate that earliest sprouting occurred in Norland followed by Desiree and Russet Burbank. Field grown, and greenhouse grown tubers exhibited earlier sprouting than] in vitro produced tubers. Overall, these investigations illustrate the potential value of micropropagation methods in predicting yielding ability and sprouting characteristics of potato cultivars

Reactivity and Chemical Characterization of Dissolved Organic Matter in an Estuary

This dissertation used Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (13C-NMR) data to quantify the changes of major chemical compound classes in high molecular weight (HMW, \u3e1kDa) DOM isolated along a transect from Great Dismal Swamp through the Elizabeth River/Chesapeake Bay system to the coastal Atlantic Ocean off Virginia, USA. Results show that both carboxylic acids and aromatic compounds are lost along the transect, while amide, and carbohydrate moieties could have a mid-transect source. Addressing the seasonal and spatial changes in the chemical composition of high molecular weight DOM using C/N ratio and δ13C signatures indicates a dramatic shift in the relative importance of the processes affecting the HMW-DOM as it moves from fresh water to the marine end member. Sorption and flocculation and reworking by heterotrophic bacteria seem to be the major players in the lower salinity region, but at the higher salinity regions the introduction of new carbon sources by primary production seems to be the major process. Applying principal component analysis (PCA) and two dimensional correlation spectroscopy to the 13C-NMR spectra of the HMW-DOM shows that HMW-DOM consists of three major components that have different biogeochemical reactivity. The first component appears to be composed of a heteropolysaccharide (HPS) component and it increases as I move to the marine end member, while the second component appears to be composed of carboxyl-rich compounds (CRC) and its carbon percentage decreases as we move away from the fresh water end member. The third component contains the major functional group of amide/amino sugar (AMS) and its carbon percentage stays almost constant regardless of the seasonal and spatial changes along the salinity transect. It seems that the HPS and CRC components are present in many aquatic environments at different relative ratios. Across aquatic environments the components contain compounds that share similar backbone structures although there is significant variation in some of their functional groups as a function of aquatic system. The 13C-label method presented here for determining the enhanced aqueous solubility of organic compounds by natural aqueous DOM is a promising new tool for investigating the reactivity of DOM. Applying the method to Dismal Swamp DOM shows that the reactivity differences between high molecular weight, low molecular weight, and total DOM samples are consistent with potential variations in their higher order structures. However, coupling the method with FTIR analysis indicates that ultrafiltration is not merely a pure physical separation but involves a chemical separation as well