Global Warming

Global warming is being affected in many ways on a daily basis and continuing using the same nonrenewable resources is hurting the human civilization as a whole today, and is going to hurt us even more in the future. The world is being affected economically today and is going to have to contribute a large sum of money to clean up the greenhouses gasses. There is also a problem with precipitation a drought due to the temperature and jet streams. Humans are choosing to migrate differently due to the change in temperatures and precipitation which goes hand in hand with the economics being affected. Although, there are ways for us to be able to not have much of a footprint on our planet through renewable energy sources

A Structured Approach to Network Security Protocol Implementation

The implementation of network security protocols has not received the same level of attention in the literature as their analysis. Security protocol analysis has successfully used inference logics, like GNY and BAN, and attack analysis, employing state space examination techniques such as model checking and strand spaces, to verify security protocols. Tools, such as the multi-dimensional analysis environment SPEAR II, exist to help automate security protocol specification and verification, however actual implementation of the specification in executable code is a task still largely left to human programmers. Many vulnerabilities have been found in implementations of security protocols such as SSL, PPTP and RADIUS that are incorporated into widely used operating system software, web servers and other network aware applications. While some of these vulnerabilities may be a result of flawed or unclear specifications, many are the result of the failure of programmers to correctly interpret and implement them. The above indicates a gap between security protocol specifications and their concrete implementations, in that there are methodologies and tools that have been established for developing the former, but not the latter. This dissertation proposes an approach to bridging this gap, describes our implementation of that approach and attempts to evaluate its success. The approach is three-fold, providing different measures to improve current ad-hoc implementation approaches: 1. From Informal to Formal Specifications: If a security protocol has been specified using informal standard notation, it can be converted, using automatic translation, to a formal specification language with well defined semantics. The formal protocol specification can then be analysed using formal techniques, to verify that the desired security properties hold. The precise specification of the protocol behaviour further serves to facilitate the concrete implementation of the protocol in code. 2. Separate Implementation Concerns: When implementing security protocols, the what and the when of protocol actions are abstracted from the how. That is, protocol logic implementation concerns, such as when and what actions should be performed on messages, should be clearly and cleanly separated from the cryptographic and network communication implementation details that implement how the actions are performed. Such high level modularity allows code implementing protocol logic to be re-used with different cryptographic algorithm implementations and network communication protocols. It also allows errors in the implementation of the cryptography to be addressed by swapping cryptographic implementations without changing the protocol logic code. The abstraction of cryptographic and network implementation is analogous to the adoption of the Dolev-Yao style models by many analysis techniques, where the cryptography itself is viewed as a black box and assumed perfect, allowing the analysis to focus on the protocol logic. Finally, this separation allows the correctness of the protocol logic implementation and cryptographic primitives implementation to be addressed separately. 3. Automated Implementation Using Code Generation We use code generation to automate the security protocol implementation process, avoiding the risk of human error in interpreting the sometimes subtle semantics of security protocol specifications. The precise nature of formal specification languages provides a base from which to specify and implement an automatic code generation tool. Our approach follows requirements identified for high integrity code generation - where feasible - to give a high level of confidence in the correctness of the generated code. In implementing the approach, we adopt the Spi Calculus for the role of formal specification language. The Spi Calculus was developed by extending the -calculus, a process algebra for describing concurrent communicating systems, to cater for the special case of network security protocols. Spi Calculus specifications can be analysed manually, by developing correctness proofs by hand, and automatically, by using model checkers such as MMC. As Spi Calculus specifications explicitly describe the actions of a security protocol, they are also particularly suitable for use as input for code generation. The implementation of the approach is split across three components that correspond to each of the parts of the approach: 1. Sn2Spi is a translator that converts an informal standard notation specification to a Spi Calculus specification, thus implementing part 1 of our approach. The converted specification can be analysed using any of the formal techniques applicable to the Spi Calculus. Once verified, the specification can be used to generate a concrete implementation using Spi2Java. 2. The Security Protocol Primitives API abstracts cryptographic and network communication operations, decoupling code that implements protocol logic from code that implements cryptographic and network operations. It provides the basic cryptographic and network communications functionality required to implement a security protocol, including: symmetric and asymmetric encryption, message digest, nonce and timestamp generation, marshalling message component data and sending and receiving messages over a network. A provider model, much like that used in the Java Cryptography Extensions API, is employed to allow different implementations to be swapped without changing the SPP client code. 3. Spi2Java is a code generator, essentially implementing a compiler from the Spi Calculus to Java code. Spi2Java uses Prolog to implement a defined mapping from Spi Calculus constructs, i.e. terms and process actions, to Java code segments. These code segments call the SPP API to access cryptographic and network functionality where needed. The mapping was developed by refining Spi constructs to Java code segments that preserve the semantics of the Spi constructs In addition, assertions are made in the code segments to ensure certain conditions are met before the implementation can continue running. Part of evaluating the effectiveness of this automated approach to security protocol implementation, involved a case study where manual implementations of the CCITT Three Message X.509 Protocol, developed by 4th year Computer Science students, and a Spi2Java generated implementation are compared. The outcome of the study favoured the automatically generated implementation, indicating the potential of the approach. Further to demonstrating the utility of code generation, we describe an SPP provider implementation developed to allow a security protocol run, including legitimate and attacker roles, to be simulated in a controlled environment. Spi2Java allows the protocol engineer to quickly and automatically generate code for protocol roles. The code can be executed using this implementation allowing the protocol engineer to step through execution of all roles, both legitimate and attacker, to gain insight into the behaviour of the protocol. The approach is evaluated in terms of the class of attacks it prevents and how it meets the identified requirements for high integrity code generation. It is also compared to existing and current work in the field. Attack classes that exploit faulty protocol logic implementation, vulnerability to type flaws and buffer overflows are prevented. The Spi2Java code generator fully meets three of the five high integrity code generation requirements: formally defined source and target languages are used; the translation software is validated; and the generated code is well structured and documented and can be traced back to the specification. Spi2Java partially meets the requirement that the mapping from source to target language constructs be formally proven to preserve the specification semantics. However the arguments given are not strictly formal. The requirement related to rigorous testing are not met due to practical resource constraints. However, Spi2Java has been used to generate real world protocol implementations that have been verified by manual inspection. Sprite, incorporating the Sn2Spi translator and Spi2Java code generator, provides a structured approach to network security protocol implementation by implementing automated translation from informal to formal security protocol specifications, and by being able to automatically generate Java implementations of network security protocols in which the security protocol engineer can have a high degree of confidence

From Molecular Cores to Planet-forming Disks with SIRTF

The SIRTF mission and the Legacy programs will provide coherent data bases for extra-galactic and Galactic science that will rapidly become available to researchers through a public archive. The capabilities of SIRTF and the six legacy programs are described briefly. Then the cores to disks (c2d) program is described in more detail. The c2d program will use all three SIRTF instruments (IRAC, MIPS, and IRS) to observe sources from molecular cores to protoplanetary disks, with a wide range of cloud masses, stellar masses, and star-forming environments. The SIRTF data will stimulate many follow-up studies, both with SIRTF and with other instruments.Comment: 6 pages, from Fourth Cologne-Bonn-Zermatt-Symposium, The Dense Interstellar Matter in Galaxie

Balanced and Restored Cross-Sections Representing Post-Miocene Crustal Extension of Fluvial Deposits, North-Central Montana to Southeast Idaho

This research is part of a larger project based on the theory of the existence of a pre-ice age, Amazon-scale river that had headwaters in the southern Colorado Plateau and flowed north through the western United States and Canada before discharging into the Labrador Sea. Stream-rounded fluvial deposits in Montana and Idaho provide evidence of sediment provenance in Nevada and Utah, as there are no confirmed bedrock sources for these sediments in Montana or Idaho. The Miocene river bed has been offset and tilted by dozens of extensional faults in the region. Some faults bound large mountain ranges including the Lost River, Lemhi, Beaverhead, Tendoy, Blacktail Deer, Ruby, Madison, and Big Belt Mountains. The reconstructed trend of the Miocene river bed provides a reference line against which to measure active faulting. We constructed five balanced cross-sections of the deformed subsurface along the Miocene river bed from north-central Montana to southeast Idaho across the faulted mountain ranges and restored the cross-sections to represent an un-deformed subsurface. This provided valuable insight into crustal deformation in these regions. Knowing the timing and extent of crustal deformation has many scientific and societal benefits. Western Montana and adjacent Idaho occupy the Inter-mountain Seismic Zone and have the potential for large earthquakes. Detailed cross-sections through this zone can provide information for development projects in faulted areas, and target potential aquifer locations where the thick river gravel has been down-faulted into the sub-surface. This research will be an important contribution to understanding the evolution of the tectonic landscape of Montana and Idaho

Generating Network Security Protocol Implementations from Formal Specifications

We describe the Spi2Java code generation tool, which we have developed in an attempt to bridge the gap between formal security protocol specification and executable implementation. Implemented in Prolog, Spi2Java can input a formal security protocol specification in a variation of the Spi Calculus, and generate a Java code implementation of that protocol. We give a brief overview of the role of code generation in the wider context of security protocol development. We cover the design and implementation of Spi2Java which we relate to the high integrity code generation requirements identified by Whalen and Heimdahl. By defining a Security Protocol Implementation API that abstracts cryptographic and network communication functionality we show that protocol logic code can be separated from underlying cryptographic algorithm and network stack implementation concerns. The design of this API is discussed, particularly its support for pluggable implementation providers. Spi2Java's functionality is demonstrated by way of example: we specify the Needham-Schroeder Public Key Authentication Protocol, and Lowe's attack on it, in the Spi Calculus and examine a successful attack run using Spi2Java generated implementation of the protocol roles

On Instanton Effects in F-theory

We revisit the issue of M5-brane instanton corrections to the superpotential in F-theory compactifications on elliptically fibered Calabi-Yau fourfolds. Elaborating on concrete geometries, we compare the instanton zero modes for non-perturbative F-theory models with the zero modes in their perturbative Sen limit. The fermionic matter zero modes localized on the intersection of the instanton with the space-time filling D7-branes show up in a geometric way in F-theory. Methods for their computation are developed and, not surprisingly, exceptional gauge group structures do appear. Finally, quite intriguing geometrical aspects of the one-loop determinant are discussed.Comment: 52 pages, 8 figures, 13 tables; v2: extended discussion of matter zero modes, refs added; v3: sections 3.3 + 4.1 restructure

Transformation of spin information into large electrical signals via carbon nanotubes

Spin electronics (spintronics) exploits the magnetic nature of the electron, and is commercially exploited in the spin valves of disc-drive read heads. There is currently widespread interest in using industrially relevant semiconductors in new types of spintronic devices based on the manipulation of spins injected into a semiconducting channel between a spin-polarized source and drain. However, the transformation of spin information into large electrical signals is limited by spin relaxation such that the magnetoresistive signals are below 1%. We overcome this long standing problem in spintronics by demonstrating large magnetoresistance effects of 61% at 5 K in devices where the non-magnetic channel is a multiwall carbon nanotube that spans a 1.5 micron gap between epitaxial electrodes of the highly spin polarized manganite La0.7Sr0.3MnO3. This improvement arises because the spin lifetime in nanotubes is long due the small spin-orbit coupling of carbon, because the high nanotube Fermi velocity permits the carrier dwell time to not significantly exceed this spin lifetime, because the manganite remains highly spin polarized up to the manganite-nanotube interface, and because the interfacial barrier is of an appropriate height. We support these latter statements regarding the interface using density functional theory calculations. The success of our experiments with such chemically and geometrically different materials should inspire adventure in materials selection for some future spintronicsComment: Content highly modified. New title, text, conclusions, figures and references. New author include

Evaluation of the impact of the voucher and accreditation approach on improving reproductive behaviors and RH status: Bangladesh

<p>Abstract</p> <p>Background</p> <p>Cost of delivering reproductive health services to low-income populations will always require total or partial subsidization by the government and/or development partners. Broadly termed "Demand-Side Financing" or "Output-Based Aid", includes a range of interventions that channel government or donor subsidies to the service user rather than the service provider. Initial findings from the few assessments of reproductive health voucher-and-accreditation programs suggest that, if implemented well, these programs have great potential for achieving the policy objectives of increasing access and use, reducing inequities and enhancing program efficiency and service quality. At this point in time, however, there is a paucity of evidence describing how the various voucher programs function in different settings, for various reproductive health services.</p> <p>Methods/Design</p> <p>Population Council-Nairobi, funded by the Bill and Melinda Gates Foundation, intends to address the lack of evidence around the pros and cons of 'voucher and accreditation' approaches to improving the reproductive health of low income women in five developing countries. In Bangladesh, the activities will be conducted in 11 accredited health facilities where Demand Side Financing program is being implemented and compared with populations drawn from areas served by similar non-accredited facilities. Facility inventories, client exit interviews and service provider interviews will be used to collect comparable data across each facility for assessing readiness and quality of care. In-depth interviews with key stakeholders will be conducted to gain a deeper understanding about the program. A population-based survey will also be carried out in two types of locations: areas where vouchers are distributed and similar locations where vouchers are not distributed.</p> <p>Discussion</p> <p>This is a quasi-experimental study which will investigate the impact of the voucher approach on improving maternal health behaviors and status and reducing inequities at the population level. We expect a significant increase in the utilization of maternal health care services by the accredited health facilities in the experimental areas compared to the control areas as a direct result of the interventions. If the voucher scheme in Bangladesh is found effective, it may help other countries to adopt this approach for improving utilization of maternity care services for reducing maternal mortality.</p

F-Theorem without Supersymmetry

The conjectured F-theorem for three-dimensional field theories states that the finite part of the free energy on S^3 decreases along RG trajectories and is stationary at the fixed points. In previous work various successful tests of this proposal were carried out for theories with {\cal N}=2 supersymmetry. In this paper we perform more general tests that do not rely on supersymmetry. We study perturbatively the RG flows produced by weakly relevant operators and show that the free energy decreases monotonically. We also consider large N field theories perturbed by relevant double trace operators, free massive field theories, and some Chern-Simons gauge theories. In all cases the free energy in the IR is smaller than in the UV, consistent with the F-theorem. We discuss other odd-dimensional Euclidean theories on S^d and provide evidence that (-1)^{(d-1)/2} \log |Z| decreases along RG flow; in the particular case d=1 this is the well-known g-theorem.Comment: 34 pages, 2 figures; v2 refs added, minor improvements; v3 refs added, improved section 4.3; v4 minor improvement

Evaluation of the impact of the voucher and accreditation approach on improving reproductive behaviors and status in Cambodia

Background: Cost of delivering reproductive health services to low-income populations will always require total or partial subsidization by government and/or development partners. Broadly termed “demand-side financing” or “output-based aid,” these strategies include a range of interventions that channel government or donor subsidies to the user rather than the service provider. Initial pilot assessments of reproductive health voucher programs suggest that they can increase access, reduce inequities, and enhance program efficiency and service quality. However, there is a paucity of evidence describing how these programs function in different settings for various reproductive health services. Methods/Design: Population Council, funded by the Bill and Melinda Gates Foundation, intends to generate evidence around the “voucher and accreditation” approaches to improving the reproductive health of low-income women in Cambodia. The study comprises four populations: facilities, providers, women of reproductive age using facilities, and women and men who have been pregnant and/or used family planning within the previous 12 months. The study will be carried out in a sample of 20 health facilities that are accredited to provide maternal and newborn health and family planning services to women holding vouchers from operational districts in three provinces: Kampong Thom, Kampot, and Prey Veng and a matched sample of non-accredited facilities in three other provinces. Health facility assessments will be conducted at baseline and endline to track temporal changes in quality of care, client out-of-pocket costs, and utilization. Facility inventories, structured observations, and client exit interviews will be used to collect comparable data across facilities. Health providers will also be interviewed and observed providing care. A population survey of about 3,000 respondents will also be conducted in areas where vouchers are distributed and similar non-voucher locations. Discussion: A quasi-experimental study will investigate the impact of the voucher approach on improving reproductive health behaviors, reproductive health status, and reducing inequities at the population level and assess effects on access, equity, and quality of care at the facility level. If the voucher scheme in Cambodia is found effective, it may help other countries adopt this approach for improving utilization and access to reproductive health and family planning services