Magnetic Force on a Current Carrying Conductor

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The Report of the Task Force on Financial Mechanisms for ICT for Development - A review of trends and an analysis of gaps and promising practices December 22, 2004 The World Summit on Information Society (WSIS), the first phase of which was concluded in Geneva in 2003, recommended that “while all existing financial mechanisms should be fully exploited to make available the benefits of information and communication technologies, a thorough review of their adequacy in meeting the challenges of ICT for development should be completed by the end of December 2004. This review shall be conducted by a Task Force under the auspices of the Secretary-General of the United Nations and submitted for consideration to the second phase of this summit.” The Secretary-General asked UNDP to take the lead in setting up Task Force on Financial Mechanisms, in collaboration with the World Bank and the United Nations Department of Economic and Social Affairs and other key partners. The following report does not necessarily reflect the views of United Nations, which should not be held responsible for its contents. Table of Contents EXECUTIVE SUMMARY 1 FINDINGS 2 CONCLUSIONS 8 1.0 THE FINANCING ISSUE IN THE WSIS-GENEVA CONTEXT 14 2.0 CONTEXT AND FRAMEWORK FOR FINANCING ICT FOR DEVELOPMENT 15 2.1 THE DEVELOPMENT RATIONALE FOR A FOCUS ON ICT 15 2.2 LEVERAGING ICT FOR DEVELOPMENT 16 2.3 FINANCING ICT FOR DEVELOPMENT 18 2.4 RECOGNIZING ACHIEVEMENTS & EXPLORING FINANCING CHALLENGES AND GAPS 20 3.0 FINANCIAL MECHANISMS: APPROACHES AND EXPERIENCE 22 3.1 INTERNATIONAL RESOURCES AND MECHANISMS 22 3.2 DOMESTIC RESOURCES AND MECHANISMS 46 4.0 ICT FOR DEVELOPMENT AND FINANCING: CHALLENGES & PROMISING PRACTICES 61 4.1 DEFINING POLICY FRAMEWORKS AND IMPLEMENTATION STRATEGIES 61 4.2 BUILDING BACKBONE INFRASTRUCTURES 67 4.3 ENSURING EFFECTIVE ACCESS 72 4.4 ENRICHING DEVELOPMENT: APPLICATIONS AND CONTENT 78 4.5 STRENGTHENING HUMAN RESOURCE CAPACITY, PROMOTING OPPORTUNITY 83 CONCLUSIONS: 89 ACKNOWLEDGEMENTS 95 TASK FORCE MEMBERS 95 ANNEX 1 DEFINITIONS OF ODA, OOF AND PRIVATE FLOWS 97 ANNEX 2 THE MONTERREY CONSENSUS AND EFFORTS OF DAC MEMBERS 98 ANNEX.3 SUMMARY OF AVAILABLE INSTRUMENTS AT MDBS 100 ANNEX 4 DONOR ICT FOR DEVELOPMENT PROGRAMMES AND EXPENDITURES SUMMARY TABLE (AS OF SEPTEMBER 2004) 103 ANNEX 5 SELECTED DONOR PROGRAMMES AND INITIATIVES 109 ANNEX 6 SELECTED UN ORGANIZATIONS ACTIVITIES/INITIATIVES – SUMMARY TABLE 117 ANNEX 7 EXAMPLE OF COMPLEXITY OF FINANCING 118 SELECTED REFERENCES 121 2 Executive Summary WSIS Context The WSIS Plan of Action requested the Secretary General of the United Nations to create a Task Force to study the issue of financial mechanisms for ICT and present a report to facilitate the discussions on the subject in preparation for Magnetic Force on a Current-Carrying Conductor Magnetic Force on a Current-Carrying Conductor Bởi: OpenStaxCollege Because charges ordinarily cannot escape a conductor, the magnetic force on charges moving in a conductor is transmitted to the conductor itself The magnetic field exerts a force on a current-carrying wire in a direction given by the right hand rule (the same direction as that on the individual moving charges) This force can easily be large enough to move the wire, since typical currents consist of very large numbers of moving charges We can derive an expression for the magnetic force on a current by taking a sum of the magnetic forces on individual charges (The forces add because they are in the same direction.) The force on an individual charge moving at the drift velocity vd is given by F = qvdB sin θ Taking B to be uniform over a length of wire l and zero elsewhere, the total magnetic force on the wire is then F = (qvdB sin θ)(N), where N is the number of charge carriers in the section of wire of length l Now, N = nV, where n is the number of charge carriers per unit volume and V is the volume of wire in the field Noting that V = Al, where A is the cross-sectional area of the wire, then the force on the wire is F = (qvdB sin θ)(nAl) Gathering terms, F = (nqAvd)lB sin θ Because nqAvd = I (see Current), 1/7 Magnetic Force on a Current-Carrying Conductor F = IlB sin θ is the equation for magnetic force on a length l of wire carrying a current I in a uniform magnetic field B, as shown in [link] If we divide both sides of this expression by l, we F find that the magnetic force per unit length of wire in a uniform field is l = IB sin θ The direction of this force is given by RHR-1, with the thumb in the direction of the current I Then, with the fingers in the direction of B, a perpendicular to the palm points in the direction of F, as in [link] The force on a current-carrying wire in a magnetic field is F = IlB sin θ Its direction is given by RHR-1 Calculating Magnetic Force on a Current-Carrying Wire: A Strong Magnetic Field Calculate the force on the wire shown in [link], given B = 1.50 T, l = 5.00 cm, and I = 20.0 A Strategy The force can be found with the given information by using F = IlB sin θ and noting that the angle θ between I and B is 90º, so that sin θ = Solution Entering the given values into F = IlB sin θ yields F = IlB sin θ = (20.0 A)(0.0500 m)(1.50 T)(1) The units for tesla are T = N A ⋅ m; thus, F = 1.50 N 2/7 Magnetic Force on a Current-Carrying Conductor Discussion This large magnetic field creates a significant force on a small length of wire Magnetic force on current-carrying conductors is used to convert electric energy to work (Motors are a prime example—they employ loops of wire and are considered in the next section.) Magnetohydrodynamics (MHD) is the technical name given to a clever application where magnetic force pumps fluids without moving mechanical parts (See [link].) Magnetohydrodynamics The magnetic force on the current passed through this fluid can be used as a nonmechanical pump A strong magnetic field is applied across a tube and a current is passed through the fluid at right angles to the field, resulting in a force on the fluid parallel to the tube axis as shown The absence of moving parts makes this attractive for moving a hot, chemically active substance, such as the liquid sodium employed in some nuclear reactors Experimental artificial hearts are testing with this technique for pumping blood, perhaps circumventing the adverse effects of mechanical pumps (Cell membranes, however, are affected by the large fields needed in MHD, delaying its practical application in humans.) MHD propulsion for nuclear submarines has been proposed, because it could be considerably quieter than conventional propeller drives The deterrent value of nuclear submarines is based on their ability to hide and survive a first or second nuclear strike As we slowly disassemble our nuclear weapons arsenals, the submarine branch will be the last to be decommissioned because of this ability (See [link].) Existing MHD drives are heavy and inefficient—much development work is needed 3/7 Magnetic Force on a Current-Carrying Conductor An MHD propulsion system in a nuclear submarine could produce significantly less turbulence than propellers and allow it to run more silently The development of a silent drive submarine was dramatized in the book and the film The Hunt for Red October Section Summary • The magnetic force on current-carrying conductors is given by F = IlB sin θ, where I is the current, l is the length of a straight conductor in a uniform magnetic field B, and θ is the angle between I and B The force follows RHR-1 with the thumb in the direction of I Conceptual Questions Draw a sketch of the situation in [link] showing the direction of electrons carrying the current, and use RHR-1 to verify the direction of the force on the wire Verify that the direction of the force in an MHD ...REVIEW ARTICLE The mystery of nonclassical protein secretion A current view on cargo proteins and potential export routes Walter Nickel Biochemie-Zentrum Heidelberg, University of Heidelberg, Germany Most of the examples of protein translocation across a membrane (such as the import of classical secretory proteins into the endoplasmic reticulum, import of proteins into mitochondria and peroxisomes, as well as protein import into and export from the nucleus), are understood in great detail. In striking contrast, the phenomenon of unconven- tional protein secretion (also known as nonclassical protein export or ER/Golgi-independent protein secretion) from eukaryotic cells was discovered more than 10 years ago and yet the molecular mechanism and the molecular identity of machinery components that mediate this process remain elusive. This problem appears to be even more complex as several lines of evidence indicate that various kinds of mechanistically distinct nonclassical export routes may exist. In most cases these secretory mechanisms are gated in a tightly controlled fashion. This review aims to provide a comprehensive overview of our current knowledge as a basis for the development of new experimental strategies designed to unravel the molecular machineries mediating ER/Golgi- independent protein secretion. Beyond solving a funda- mental problem in current cell biology, the molecular analysis of these processes is of major biomedical importance as these export routes are taken by proteins such as angio- genic growth factors, inflammatory cytokines, components of the extracellular matrix which regulate cell differentiation, proliferation and apoptosis, viral proteins, and parasite surface proteins potentially involved in host infection. Keywords: unconventional protein secretion; nonclassical export; protein targeting; membrane translocation; extra- cellular localization; FGF-2 trafficking; galectin trafficking; Leishmania HASPB trafficking; interleukin 1a and 1b trafficking; ER/Golgi-independent protein secretion. Introduction Soluble secretory proteins typically contain N-terminal signal peptides that direct them to the translocation apparatus of the endoplasmic reticulum (ER) [1]. Following vesicular transport from the ER via the Golgi to the cell surface, lumenal proteins are released into the extracellular space by fusion of Golgi-derived secretory vesicles with the plasma membrane [2–5]. This pathway of protein export from eukaryotic cells is known as the classical or ER/Golgi- dependent secretory pathway. However, more than 10 years ago, it was reported that interleukin 1b (IL1b) and galectin-1 (alsoreferredtoasL-14)couldbeexportedfromcellsinthe absence of a functional ER/Golgi system [6,7]. Since then, the list of proteins demonstrated to be secreted by uncon- ventional means is steadily growing. Figure 1 gives an overview of cellular, viral and parasitic proteins that have been shown to be exported by mechanisms that are operational in the absence of a functional ER/Golgi system. The basic observations (summarized previously in [8,9]) that led to the proposal of alternative pathways of eukaryotic protein secretion are (a) the lack of conventional signal peptides in the secretory proteins in question, (b) the exclusion of these proteins from classical secretory 90 Introduction: Health-related retrospective databases, in particular claims databases, continue to be an important data source for outcomes research. However, retrospec- tive databases pose a series of methodological challenges, some of which are unique to this data source. Methods: In an effort to assist decision makers in evalu- ating the quality of published studies that use health- related retrospective databases, a checklist was developed that focuses on issues that are unique to database studies or are particularly problematic in database research. This checklist was developed primarily for the commonly used medical claims or encounter-based databases but could potentially be used to assess retrospective studies that employ other types of databases, such as disease registries and national survey data. Results: Written in the form of 27 questions, the check- list can be used to guide decision makers as they consider the database, the study methodology, and the study con- clusions. Checklist questions cover a wide range of issues, including relevance, reliability and validity, data linkages, eligibility determination, research design, treatment effects, sample selection, censoring, variable definitions, resource valuation, statistical analysis, generalizability, and data interpretation. Conclusions: For many of the questions, key references are provided as a resource for those who want to further examine a particular issue. Keywords: claims databases, outcomes research, research design, statistics. Address correspondence to: Brenda Motheral, PhD (Chair), Vice President, Express Scripts, 13900 Riverport Drive, Maryland Heights, MO 63043. E-mail: bmotheral@express-scripts.com Volume 6 • Number 2 • 2003 V ALUE IN HEALTH A Checklist for Retrospective Database Studies—Report of the ISPOR Task Force on Retrospective Databases Brenda Motheral, MBA, PhD, 1 John Brooks, PhD, 2 Mary Ann Clark, MHA, 3 William H. Crown, PhD, 4 Peter Davey, MD, FRCP, 5 Dave Hutchins, MBA, MHSA, 6 Bradley C. Martin, PharmD, PhD, 7 Paul Stang, PhD 8 1 Express Scripts, Maryland Heights, MO, USA; 2 College of Pharmacy, University of Iowa, Iowa City, IA, USA; 3 Boston Scientific Corporation, Natick, MA, USA; 4 The Medstat Group, Cambridge, MA, USA; 5 Department of Clinical Pharmacology, University of Dundee, Dundee, UK; 6 Advanced PCS Health Systems, Inc., Scottsdale, AZ, USA; 7 College of Pharmacy, University of Georgia, Athens, GA, USA; 8 Galt Associates, Inc., Blue Bell, PA, USA ABSTRACT Introduction What Is the Purpose of This Checklist? This checklist is intended to assist decision makers in evaluating the quality of published studies that use health-related retrospective databases. Numer- ous databases are available for use by researchers, particularly within the United States. Because the databases have varying purposes, their content can vary dramatically. Accordingly, the unique advantages and disadvantages of a particular data- base must be borne in mind. In reviewing a data- base study, it is important to assess whether the database is suitable for addressing the research question and whether the investigators have used an appropriate methodology in reaching the study con- clusions. The checklist was written in the form of 27 questions to guide decision makers as they con- sider the database, the study methodology, and the study conclusions. For many of the questions, key references are provided as a resource for those who want This Provisional PDF corresponds to the article as it appeared upon acceptance. Fully formatted PDF and full text (HTML) versions will be made available soon. Spin-related tunneling through a nanostructured electric-magnetic barrier on the surface of a topological insulator Nanoscale Research Letters 2012, 7:90 doi:10.1186/1556-276X-7-90 Zhenhua Wu (zhwu@semi.ac.cn) Jun Li (lijun@xmu.edu.cn) ISSN 1556-276X Article type Nano Express Submission date 30 August 2011 Acceptance date 27 January 2012 Publication date 27 January 2012 Article URL http://www.nanoscalereslett.com/content/7/1/90 This peer-reviewed article was published immediately upon acceptance. It can be downloaded, printed and distributed freely for any purposes (see copyright notice below). Articles in Nanoscale Research Letters are listed in PubMed and archived at PubMed Central. For information about publishing your research in Nanoscale Research Letters go to http://www.nanoscalereslett.com/authors/instructions/ For information about other SpringerOpen publications go to http://www.springeropen.com Nanoscale Research Letters © 2012 Wu and Li ; licensee Springer. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Spin-related tunneling through a nanostructured electric–magnetic barrier on the surface of a topological insulator Zhenhua Wu ∗1,2 and Jun Li 3 1 SKLSM, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083, China 2 CAE Team, Semiconductor R&D Center, Samsung Electronics Co., Ltd., Gyeonggi-Do, Korea 3 Department of Physics, Semiconductor Photonics Research Center, Xiamen University, Xiamen 361005, China ∗ Corresponding author: zhwu@semi.ac.cn Email address: JL: lijun@xmu.edu.cn Abstract We investigate quantum tunneling through a single electric and/or magnetic barrier on the surface of a three-dimensional topological insulator. We found that (1) the propagating behavior of electrons in such system exhibits a strong dependence on the direction of the incident electron wavevector and incident energy, giving the possibility to construct a wave vector and/or energy filter; (2) the spin orientation can be tuned by changing the magnetic barrier structure as well as the incident angles and energies. PACS numbers: 72.25.Dc; 73.20 r; 73.23 b; 75.70 i. 2 1. Introduction The recent discovery of a new quantum state of matter, topological insulator, has gen- erated a lot of interest due to its great scientific and technological imp ortance [1–5]. In a topological insulator, spin–orbit coupling opens an energy gap in the bulk, and results in helical surface states residing in the bulk gap in the absence of magnetic fields. Such surface states are spin-dependent and are topologically protected by time-reversal symmetry [4–7] and distinct from conventional surface states, which are fragile and depend sensitively on the details of the surface geometry and bonding. This discovery sparked intensive experimental and theoretical interests, both for its fundamental novel electronics properties as well as possible applications in a new generation of electric devices. Very recently, the surface states in Bi-based alloys, Bi 1−x Sb x , Bi 2 Se 3 , Bi 2 Te 3 , were were This Provisional PDF corresponds to the article as it appeared upon acceptance. Fully formatted PDF and full text (HTML) versions will be made available soon. Spin-related tunneling through a nanostructured electric-magnetic barrier on the surface of a topological insulator Nanoscale Research Letters 2012, 7:90 doi:10.1186/1556-276X-7-90 Zhenhua Wu (zhwu@semi.ac.cn) Jun Li (lijun@xmu.edu.cn) ISSN 1556-276X Article type Nano Express Submission date 30 August 2011 Acceptance date 27 January 2012 Publication date 27 January 2012 Article URL http://www.nanoscalereslett.com/content/7/1/90 This peer-reviewed article was published immediately upon acceptance. It can be downloaded, printed and distributed freely for any purposes (see copyright notice below). Articles in Nanoscale Research Letters are listed in PubMed and archived at PubMed Central. For information about publishing your research in Nanoscale Research Letters go to http://www.nanoscalereslett.com/authors/instructions/ For information about other SpringerOpen publications go to http://www.springeropen.com Nanoscale Research Letters © 2012 Wu and Li ; licensee Springer. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Spin-related tunneling through a nanostructured electric–magnetic barrier on the surface of a topological insulator Zhenhua Wu ∗1,2 and Jun Li 3 1 SKLSM, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083, China 2 CAE Team, Semiconductor R&D Center, Samsung Electronics Co., Ltd., Gyeonggi-Do, Korea 3 Department of Physics, Semiconductor Photonics Research Center, Xiamen University, Xiamen 361005, China ∗ Corresponding author: zhwu@semi.ac.cn Email address: JL: lijun@xmu.edu.cn Abstract We investigate quantum tunneling through a single electric and/or magnetic barrier on the surface of a three-dimensional topological insulator. We found that (1) the propagating behavior of electrons in such system exhibits a strong dependence on the direction of the incident electron wavevector and incident energy, giving the possibility to construct a wave vector and/or energy filter; (2) the spin orientation can be tuned by changing the magnetic barrier structure as well as the incident angles and energies. PACS numbers: 72.25.Dc; 73.20 r; 73.23 b; 75.70 i. 2 1. Introduction The recent discovery of a new quantum state of matter, topological insulator, has gen- erated a lot of interest due to its great scientific and technological imp ortance [1–5]. In a topological insulator, spin–orbit coupling opens an energy gap in the bulk, and results in helical surface states residing in the bulk gap in the absence of magnetic fields. Such surface states are spin-dependent and are topologically protected by time-reversal symmetry [4–7] and distinct from conventional surface states, which are fragile and depend sensitively on the details of the surface geometry and bonding. This discovery sparked intensive experimental and theoretical interests, both for its fundamental novel electronics properties as well as possible applications in a new generation of electric devices. Very recently, the surface states in Bi-based alloys, Bi 1−x Sb x , Bi 2 Se 3 , Bi 2 Te 3 , were were ... tesla are T = N A ⋅ m; thus, F = 1.50 N 2/7 Magnetic Force on a Current- Carrying Conductor Discussion This large magnetic field creates a significant force on a small length of wire Magnetic force. . .Magnetic Force on a Current- Carrying Conductor F = IlB sin θ is the equation for magnetic force on a length l of wire carrying a current I in a uniform magnetic field B, as shown in... perpendicular to B? 5/7 Magnetic Force on a Current- Carrying Conductor What is the direction of the magnetic field that produces the magnetic force shown on the currents in each of the three cases