In vitro antioxidant activity and polyphenol estimation of methanolic extract of endangered medicinal tree species, Hildegardia populifolia (Roxb.) Schott & Endl.

Antioxidant property of methanolic leaf and stem bark extracts of the endangered medicinal tree species, Hildegardia populifolia was evaluated by studying the contents of total phenolics, tannins and flavonoids, free radical scavenging activity using 1,1-diphenyl-2-picryl hydrozyl (DPPH), hydroxyl radical scavenging activity, reducing power activity, ABTS·+ assay and metal chelating activity. The results of the study revealed that both the parts studied were found to have potent antioxidant activity against DPPH, hydroxyl and ABTS·+ radicals with the IC50 value of 92.86 and 309.83 for methanolic extracts of leaf and stem bark respectively for DPPH radicals and 820.30 (leaf) and 456.71 (stem bark) for hydroxyl radicals. Therefore methanolic extracts of both leaf and stem bark of H. populifolia can be considered as a new potential source of natural antioxidants for pharmaceutical industries

Myanmarese Refugees in Thailand: the Need for Effective Protection

This paper deals with the Thai government\u27s policy on refugees with a special focus on refugees from Myanmar. It is designed to give suggestions to international human rights NGOs working in the Thai-Myanmar border areas for the protection of the human rights of Myanmarese refugees. Most international human rights NGOs in this region are lobbying for the Thai government to ratify the Refugee Convention or at the very least, take active steps towards the protection of refugees under customary international law. This paper is, however, concerned by these NGOs’ reliance on the ratification of the Convention as a solution to all the problems associated with refugee protection in the region. It is understandable that establishing a structured legal regime (positive law) is crucial. But, we are also in favor of the adoption of simultaneous measures, which, if successful, in the long-run will create an environment that is conducive to a law that is respected and effectively implemented. This paper concludes that irrespective of when the law on refugee protection is brought into force in Thailand, the recommended non-legal measures will go a long way in setting the stage for the law to be implemented efficiently at some point in the future

Myanmarese Refugees in Thailand: the Need for Effective Protection

This paper deals with the Thai government\u27s policy on refugees with a special focus on refugees from Myanmar. It is designed to give suggestions to international human rights NGOs working in the Thai-Myanmar border areas for the protection of the human rights of Myanmarese refugees. Most international human rights NGOs in this region are lobbying for the Thai government to ratify the Refugee Convention or at the very least, take active steps towards the protection of refugees under customary international law. This paper is, however, concerned by these NGOs’ reliance on the ratification of the Convention as a solution to all the problems associated with refugee protection in the region. It is understandable that establishing a structured legal regime (positive law) is crucial. But, we are also in favor of the adoption of simultaneous measures, which, if successful, in the long-run will create an environment that is conducive to a law that is respected and effectively implemented. This paper concludes that irrespective of when the law on refugee protection is brought into force in Thailand, the recommended non-legal measures will go a long way in setting the stage for the law to be implemented efficiently at some point in the future

ADAPTIVE CODING TECHNIQUES TO IMPROVE BER IN OFDM SYSTEM

Adaptive modulation and diversity combining represent very important adaptive solutions for the future generations of communication systems. In order to improve the performance and the efficiency of wireless communication systems these two techniques have been recently used jointly in new schemes named joint adaptive modulation and diversity combining .The highest spectral efficiency with the lowest possible combining complexity, given the fading channel conditions and the required error rate performance. Increase the spectral efficiency with a slight increase in the average number of combined path for the low signal to noise ratio (SNR) range while maintaining compliance with the bit error rate (BER)

A Study of the Gradient Drift Instability in the High-Latitude Ionosphere Using the Utah State University Time Dependent Ionospheric Model

Research over the years has established that the Gradient Drift Instability process causes small-scale irregularities, mostly along the edges of the high-latitude polar cap patches. Studying these irregularities will help in the development of a global Scale Ionospheric model, which is a central part of a global space weather forecast system. Much theoretical work has been done with varying degrees of complexity to study this instability in the high latitude patches. In this work we have used the Utah State University Time Dependent Ionospheric Model to model the high-latitude patches, calculate the growth rate of the instability, and perform a macro-scale study of the phenomenon. This is the first time that real ionospheric values have been used to calculate the growth rate and to provide two-dimensional maps identifying Gradient Drift Instability-caused irregularity regions in the polar cap. Our research shows that regions of intense instability occur along the edges of the tongue of ionization and its throat regions with strong rates along the borders of the cusp region

Persona Concept for Privacy and Authentication

This paper describes ongoing research and development aimed at creating a trustworthy software-based model called the Persona Concept.  The “Persona Architecture” uses “web services” to implement this model and is designed to provide the consumer direct control over their identity, credentials and private data.  Credentials are expressed as third-party assertions encapsulated in certificates using Secure Assertion Markup Language (SAML) and are digitally signed. The architecture also supports distributed management of electronic credentials and aims at operating across various fixed and mobile platforms including cell phones and wireless Portable Digital Assistants(PDA’s)

Effect of Pulse Voltage Trimming on Different Characteristics of Polymer Thick Film Resistors

AbstractIn this work we study in more details the impact of pulse voltage trimming on different characteristics of thick film resistors based on (PVC-Graphite) resistor compositions. This study focuses on the change of resistivity, thermal coefficient of resistance and current noise. In order to realize a non cut trimming without damage to the resistor surface of thick film resistors for electronic devices, a pulse voltage trimming method (PVTM) has been developed. This trimming method having resistance adjustments are due to pulse peak voltage and the number of pulse group. TCR and current noise of trimmed resistors are considerably improved by this trimming technique in the case of higher resistivity materials and worsen in the case of lower resistivity materials and there is no loss in power handling capacity of trimmed resistors. We propose a description of pulse voltage trimming which can explain the observed changes in characteristics of the samples

Persona concept : system architecture and prototypes

This project explores a security framework, called the Persona Concept, aimed at giving the user greater control over their private data in cyberspace, in particular, their electronic credentials. The background for the Persona Concept, along with the requirements identified can be found in three (3) technical publications produced by Kal Toth and myself in 2003 (see list of references [1], [2] and [3]). The Persona Concept uses a Persona Server as the secure storehouse for persona data such as credit card and bank account identifiers as well electronic credentials such as X.509 certificates. The data is secured using public key encryption. The server component interacts with the user via a Persona Client which obtains X-509 Certificates on behalf of the user from a Certification Authority (CA) service. Interaction among the various components (Persona Server, Persona Client and Certification Authority) is enabled by the use of Web Services. This project focused on managing the user data across these components including the creation, secure storage and retrieval of Persona data to and from the Persona Server using Simple Object Application Protocol (SOAP) and under the control of public key encryption schemes. SOAP is an open XML-based application-level Internet protocol for implementing distributed access to object-oriented services deployed on the Web. SOAP is designed to allow applications running on a range of platforms to access remote objects and applications on servers across a TCP/IP network. In addition to this, the project built upon the work by Ike Chen (OSU M.S. graduate project in 2004) [4] by enabling X-509 Certificate file transfer between the client and Certification Authority using SOAP (improvements were made to the mechanisms for transferring files, particularly in support of X.509 certificates). A Java-based prototype client called the Persona Client (PC) was created and used in conjunction with a small local password-based security scheme to protect the private key data on the user device. My project first implemented the upgrade to the Certification Authority services and detailed the various policies surrounding storage of data. I then implemented the Persona Client which enabled me to test the persona services in place. I then implemented the encryption schemes and the server components enabling the secure storage and transfer of Persona Data. Components to create, edit and delete data were packaged and published as services to be used by the Persona Client. Future extensions of this project could include exploring custom credential generation based on Security Assertion Markup Language (SAML) and Extensible Access Control Markup Language (XACML) which together can be used to specify XML-based credentials and access control policies for an enterprise. Other extensions include the implementation of discretionary and mandatory security policies using XACML to allow users to conduct transactions across various domains

Synthetic, Structural, Spectroscopic, Catalytic and Mechanistic Studies of Palladium Complexes with Bidentate Carbene Ligands

Carbenes are strong donor ligands widely used in metal catalyzed organic reactions. In early work, N-heterocyctic carbenes (NHCs) were considered as mimics for tertiary phosphine ligands, but subsequently they were shown to be superior to phosphine ligands in terms of activity and scope for many catalytic reactions. Bidentate carbenes are potentially more stable than monodentate carbene due to the chelate effect. A possible pathway for tuning the metal reactivity is bite angle variation. Donor abilities of imidazole-derived bis(NHCs), bis acyclic diaminocarbenes, bitriazole bis(NHCs), "abnormal" C4-bound bis(NHCs), and bis(phosphines), and thus their trans influence and effect on metal electrophilicity, were studied using methylisocyanide as an IR probe. Donor abilities of ligands were correlated with structural parameters such as bite angle, and carbene dihedral angle. Acetonitrile adducts of [(chelate)Pd]2+ complexes were examined as catalysts for electrophilic cyclizations of acetylenic aldehydes with alcoChemistry Departmen