Spin-Transfer-Torque Driven Magneto-Logic OR, AND and NOT Gates

We show that current induced magneto-logic gates like AND, OR and NOT can be designed with the simple architecture involving a single nano spin-valve pillar, as an extension of our recent work on spin-torque-driven magneto-logic universal gates, NAND and NOR. Here the logical operation is induced by spin-polarized currents which also form the logical inputs. The operation is facilitated by the simultaneous presence of a constant controlling magnetic field, in the absence of which the same element operates as a magnetoresistive memory element. We construct the relevant phase space diagrams for the free layer magnetization dynamics in the monodomain approximation and show the rationale and functioning of the proposed gates. The flipping time for the logical states of these non-universal gates is estimated to be within nano seconds, just like their universal counter parts.Comment: 9 pages,7 figure

New geometries associated with the nonlinear Schr\"{o}dinger equation

We apply our recent formalism establishing new connections between the geometry of moving space curves and soliton equations, to the nonlinear Schr\"{o}dinger equation (NLS). We show that any given solution of the NLS gets associated with three distinct space curve evolutions. The tangent vector of the first of these curves, the binormal vector of the second and the normal vector of the third, are shown to satisfy the integrable Landau-Lifshitz (LL) equation ${\bf S}_u = {\bf S} \times {\bf S}_{ss}$, (${\bf S}^2=1$). These connections enable us to find the three surfaces swept out by the moving curves associated with the NLS. As an example, surfaces corresponding to a stationary envelope soliton solution of the NLS are obtained.Comment: 13 pages, 3 figure

Bifurcation and chaos in spin-valve pillars in a periodic applied magnetic field

We study the bifurcation and chaos scenario of the macro-magnetization vector in a homogeneous nanoscale-ferromagnetic thin film of the type used in spin-valve pillars. The underlying dynamics is described by a generalized Landau-Lifshitz-Gilbert (LLG) equation. The LLG equation has an especially appealing form under a complex stereographic projection, wherein the qualitative equivalence of an applied field and a spin-current induced torque is transparent. Recently chaotic behavior of such a spin vector has been identified by Zhang and Li using a spin polarized current passing through the pillar of constant polarization direction and periodically varying magnitude, owing to the spin-transfer torque effect. In this paper we show that the same dynamical behavior can be achieved using a periodically varying applied magnetic field, in the presence of a constant DC magnetic field and constant spin current, which is technically much more feasible, and demonstrate numerically the chaotic dynamics in the system for an infinitely thin film. Further, it is noted that in the presence of a nonzero crystal anisotropy field chaotic dynamics occurs at much lower magnitudes of the spin-current and DC applied field.Comment: 8 pages, 7 figures. To appear in Chao

Information Disclosure Strategies for Green Industries

Environmental information disclosure strategies, which involve corporate attempts to increase the availability of information on pollution and emissions, can become a basis for a new wave of environmental protection policy that follows and has the potential to complement traditional command and control and market-based approaches. Although a growing body of literature and operational programs suggest that publicly disclosing the information can motivate improved corporate environmental performance, this phenomenon remains poorly understood. This paper reviews the economic and legitimacy theory behind information disclosure and analyses the current practice and programs adopted in industrialized and industrializing countries.environmental information disclosure; toxic release inventory; government disclosure programs; materials accounting; sector facility indexing; pollution and emissions; environmental performance

A Communitarian Approach to Accountability for the Common Good: A Case Study of Community Participation in Planning and Policy Making for Lake Taupo

This thesis seeks to gain a theoretical and empirical understanding of the meaning of a communitarian approach to accountability for the common good (CAACG). The hermeneutic analysis adopted in this study starts by explaining the researcher's pre-understandings which includes contemporary ideas on accountability, communitarianism and sustainability. A theoretical communitarian model was designed by synthesising these ideas. Using the theoretical model the researcher attempted to advance the meaning of CAACG in multiple contexts which include: the global context on sustainability; the New Zealand context on local governance; and more specifically in the context of planning and policy making for the sustainable development of the Taupo District. The use of such multiple contexts is crucial for this study. This is because communitarian ideology in New Zealand has historical roots in Local Government which, in recent years has been influenced by the global discourse on sustainable development. The adoption of multiple contexts is aimed at providing a holistic and historical understanding of planning and policy making processes in the Taupo District and the manifestation of CAACG in the processes. In this interpretive study the term text is defined as the empirical data which consists of public documents, website material, minutes of community meetings, field notes and transcriptions of interviews. The empirical data is about processes and outcomes of collaboration between the community groups, public authorities and private entities in formulating strategies and policies for sustainable development of the Taupo District. Interpretation of the empirical data involved understanding the text from the vantage point of the pre-understandings of the interpreter. The interpretation of the text is is aimed at explaining the manifestation of CAACG in the Taupo District. The methodological orientations of the thesis are predominantly consistent with the hermeneutic tradition of Gadamer (1975). However, although the interpreter started with the intention of strictly confining to the subjectivist approach of Gadamer (1975), at times the hermeneutic methodology adopted by the researcher encroached into the methodological orientations of objectivist hermeneutics. The use of objectivist hermeneutic was inevitable as it was necessary to understand the authorial intention in the text before the interpreter understands the text from the perspective of his pre-understandings. Hence, the researcher rejects the assumption of objective-subjective dichotomy and subscribes more to the philosophical arguments advanced by contemporary scholars (such as Boland Jr, 1989 and Ricoeur, 1981) who find both the subjective and objective philosophies as necessary for interpreting texts. The hermeneutic analysis undertaken in this study suggests that the meaning of CAACG appears in the context of communal processes (including planning and policy making processes) and the strategies and policies formulated by the Taupo community. The meaning of CAACG may not be obvious to any reader of the text . It arises from the interpretation of the text from the perspective of the interpreter's pre-understandings on a communitarian approach to accountability. The interpretation suggests the existence of a community of interests, community values and concerns, and communal processes in the Taupo District. Community values and concerns are associated with Lake Taupo. The primary concern of the community is the pollution of Lake Taupo caused by animal farming in the land surrounding the lake and the impact the pollution has on the environmental, economic and cultural values of the community. The communal processes involved collaboration between the community and public authorities in planning and policy making for the protection of Lake Taupo. The interpretation also indicates the manifestation of several dimensions of accountability in the communal processes; joint accountability or 360 degree accountability in the Taupo District; and the holistic meaning of environmental and social accounting. In the Taupo District the operation of the CAACG can be affected by several factors. Symmetry of power can be affected in terms of the preferential treatment given to the indigenous community and its segregation from the rest of the community. The strong influence of local authorities in the planning and decision making processes makes the community appear helpless without the local authorities. Communitarian processes intended to empower the community may actually strengthen the position of local authorities. Power has actually shifted from Central Government to local authorities and may not necessarily have shifted to communities. However, the endeavours to engage the community in the Taupo District can be seen as attempts to build the capacity of the community to participate in the processes and time will tell how effective the CAACG will prove to be. This thesis is the pioneer in advancing the theorization of the CAACG and has added a substantial contribution to accountability literature. It suggests a new way of looking at environmental and social accounting in which the emphasis is on community involvement through reporting and deliberation (dialectical dimension of accountability) on the impacts of human activities on the natural environment. The CAACG is premised on the centrality of community and the assumption of a 360 degree accountability in which everyone in the community has mutual responsibility to protect the common good and can be subject to critical enquiry for the adverse impacts of their activities on the common good. The CAACG does not accord private corporations the privilege status of reporting entities but considers environmental and social accounting as the agenda of the community. The concept of CAACG is not utopian as it may sound to some readers of this thesis. There are ample evidence of communities throughout the world demanding a voice in statutory planning and decision making for sustainable development. The increasing focus on environmental sustainability and community participation in the planning and decision making processes arises from greater awareness of the detrimental impacts of environmental pollution and the realisation that the decision on the common good cannot be left to free market forces and private corporations. The natural environment belongs to a community of interests which wants to participate in joint responsibility and collective planning and decision making. No individual or group has the right to make decisions about the natural environment without consulting the community

Evaluation of antipyretic activity of ethyl acetate extract of Adenema hyssopifolium G. Don in a rat model

AbstractObjectiveTo evaluate the effect of ethyl acetate extract of Adenema hyssopifolium (AHEAE) on normal body temperature and brewer's yeast-induced pyrexia rats.MethodsPreliminary phytochemical tests, acute toxicity tests and antipyretic evaluation were carried out in ethyl acetate extract of Adenema hyssopifolium. Two doses of the extract (300 or 600 mg/kg orally) and standard antipyretic agent, paracetamol at a dose of 150 mg/kg were administered to various group of the rats. Mean rectal temperature before and after treatment was noted.ResultsThe phytochemical analysis of AHEAE revealed the presence of flavonoid and iridoid glycosides as major phytoconstituents. The administration of AHEAE at a dose of 300 or 600 mg/kg produced significant reduction (P<0.001 and P<0.01) of the body temperature in normal and pyrexia rats on a dose dependent manner. The antipyretic influence of AHEAE was comparable to that of standard antipyretic agent, paracetamol (150 mg/kg), and onset of action and reduction in pyrexia towards normal body temperature was delayed when compared to paracetamol treatment. At dose of 600 mg/kg, AHEAE reduced pyrexia to normal body temperature at 4 h after its administration compared to reduction of pyrexia to normal body temperature at 2 h by standard drug. The reduction of fever was consistent in paracetamol group from 2 to 4 h after its administration to normal body temperature compared to AHEAE treatments.ConclusionsOur present results corroborate with the traditional notion of Adenema hyssopifolium G. DON that is being used as an effective cure of fever and add authenticity to claim of indigenous healers that the taxon is a potential antipyretic agent