Charge pumping and the colored thermal voltage noise in spin valves

Spin pumping by a moving magnetization gives rise to an electric voltage over a spin valve. Thermal fluctuations of the magnetization manifest themselves as increased thermal voltage noise with absorption lines at the ferromagnetic resonance frequency and/or zero frequency. The effect depends on the magnetization configuration and can be of the same order of magnitude as the Johnson-Nyquist thermal noise. Measuring colored voltage noise is an alternative to ferromagnetic resonance experiments for nano-scale ferromagnetic circuits.Comment: 9 pages, 2 figure

Anatomy of Spin-Transfer Torque

Spin-transfer torques occur in magnetic heterostructures because the transverse component of a spin current that flows from a non-magnet into a ferromagnet is absorbed at the interface. We demonstrate this fact explicitly using free electron models and first principles electronic structure calculations for real material interfaces. Three distinct processes contribute to the absorption: (1) spin-dependent reflection and transmission; (2) rotation of reflected and transmitted spins; and (3) spatial precession of spins in the ferromagnet. When summed over all Fermi surface electrons, these processes reduce the transverse component of the transmitted and reflected spin currents to nearly zero for most systems of interest. Therefore, to a good approximation, the torque on the magnetization is proportional to the transverse piece of the incoming spin current.Comment: 16 pages, 8 figures, submitted to Phys. Rev.

Ambivalence in emotion-focused therapy for depression: the maintenance of problematically dominant self-narratives

Objective: Ambivalence can be understood as a cyclical movement between an emerging narrative novelty—an Innovative Moment (IM)—and a return to a problematically dominant self-narrative. The return implies that the IM, with its potential for change is devalued right after its emergence. Our goal is to test the hypothesis that the probability of the client expressing such form of ambivalence decreases across treatment in good-outcome cases but not in poor-outcome cases. Method: Return-to-the-Problem Markers (RPMs) signaling moments of devaluation of IMs were coded in passages containing IMs in six clients with major depression treated with emotion-focused therapy: three good-outcome cases and three poor-outcome cases. Results: The percentage of IMs with RPMs decreased across therapy in good-outcome cases, whereas it remained unchanged and high in the poor-outcome cases. Conclusions: These results were consistent with the theoretical suggestion that therapeutic failure may be associated with this form of ambivalence.Obiettivo: L'ambivalenza può essere considerata come un movimento ciclico tra un nuovo elemento narrativo emergente - Innovative Moment (IM) - e il ritorno ad una auto-narrazione problematica dominante. Il ritorno implica che il IM perde il proprio potenziale di favorire un cambiamento nel momento in cui emerge. Il nostro obiettivo è quello di verificare l'ipotesi che la probabilità che il paziente possa esprimere tale forma di ambivalenza diminuisce nel corso di un trattamento che ha un buon esito, ma non nei casi con esito negativo. Metodo: in sei pazienti affetti da depressione maggiore trattati con terapia focalizzata sulle emozioni, sono stati codificati i passaggi contenenti IM utilizzando il Return-to-the-Problem Markers (RPMs) che segnala i passaggi in cui IM vengono svalutati: tre casi con buon esito e tre con esito negativo. Risultati: La percentuale di IM con gli RPM diminuiva nel corso delle terapie dei casi con buon esito, mentre è rimasto invariato ed elevato nei casi con scarso esito. Conclusioni: Questi risultati sono coerenti con il presupposto teorico che il fallimento terapeutico possa essere associato a questa forma di ambivalenza.Objetivo: A ambivalência pode ser entendida como um movimento cíclico entre uma novidade narrativa emergente – um Momento de Inovação (MI) – e um retorno à narrativa problemática dominante. O retorno implica que o MI, com o seu potencial para a mudança, seja desvalorizado logo após a sua emergência. O nosso objetivo é testar a hipótese de que a probabilidade do cliente expressar tal forma de ambivalência diminui ao longo do tratamento em casos de sucesso mas não em casos de insucesso terapêutico. Método: Marcadores de Retorno ao Problema (MRP) que assinalam momentos de desvalorização dos MIs foram codificados em passagens contendo MIs em seis casos de clientes com depressão major tratados com terapia focada nas emoções: três casos de sucesso e três casos de insucesso. Conclusões: Estes resultados foram consistentes com as sugestões teóricas de que o insucesso terapêutico poderá estar associado a esta forma de ambivalência.Ziel: Ambivalenz kann als zyklische Bewegung zwischen einer emergenten narrativen Neuheit – einem Innovative Moment (IM) – und einer Rückkehr zu einer problematischen dominanten Selbst-Erzählung verstanden werden. Diese Rückkehr impliziert, dass der IM mit seinem Potential für Veränderung direkt nach seinem Auftauchen abgewertet wird. Unser Ziel ist die Hypothese zu testen, dass die Wahrscheinlichkeit, dass der Klient eine solche Form der Ambivalenz zeigt, bei Fällen mit gutem Therapieergebnis über die Behandlung abnimmt, aber nicht in Fällen mit schlechtem Ergebnis. Methode: Rückkehr-zu-dem-Problem Marker (RPMs), die Momente signalisieren, in denen IMs abgewertet werden, wurden in Passagen, die IMs beinhalten, von sechs Klienten mit Major Depression, die mit emotionsfokussierter Therapie behandelt wurden, kodiert: 3 Fälle mit gutem und 3 Fälle mit schlechtem Therapieergebnis. Ergebnisse: Der Prozentsatz von IMs mit RPMs verringerte sich bei Fällen mit gutem Ergebnis über die Therapie hinweg, wohingegen er in den Fällen mit schlechtem Ergebnis unverändert und hoch blieb. Schlussfolgerung: Die Ergebnisse waren mit dem theoretischen Vorschlag konsistent, dass therapeutischer Misserfolg mit dieser Form der Ambivalenz assoziiert ist.目標：矛盾可以視為是種擺盪在新產生的新穎敘說—創意時刻(IM)—和回復到一種有問題的支配性自我敘說之間的循環動作。回復意味著潛藏改變契機的IM，其價值在出現後即被摒棄。我們的目標是檢視以下假設的可能性：「在具良好成效的案例中，案主在治療歷程中表達這種形式的矛盾會降低；而在不良成效的案例中則否」。方法：在六位具有嚴重憂鬱症患者的IM段落中，找到顯示IM價值降低時刻的故態復萌標記（RPMs）並加以編碼。這六位患者均接受情緒焦點治療，其中三位為具良好成效案例，另外三位為不良成效案例。結果：在具良好成效案例中，IM當中具有RPM的比率降低；而在不良成效的案例中，RPM的比率維持不變或更高。結論：此結果與理論假設一致，即假設治療的失敗可能與這種形式的矛盾有關

Current induced switching of magnetic domains to a perpendicular configuration

In a ferromagnet--normal-metal--ferromagnet trilayer, a current flowing perpendicularly to the layers creates a torque on the magnetic moments of the ferromagnets. When one of the contacts is superconducting, the torque not only favors parallel or antiparallel alignment of the magnetic moments, as is the case for two normal contacts, but can also favor a configuration where the two moments are perpendicular. In addition, whereas the conductance for parallel and antiparallel magnetic moments is the same, signalling the absence of giant magnetoresistance in the usual sense, the conductance is greater in the perpendicular configuration. Thus, a negative magnetoconductance is predicted, in contrast with the usual giant magnetoresistance.Comment: 4 pages, 3 figures, major rewriting of the technical par

Looking both ways

On the occasion of the 25th anniversary of the journal, Psychotherapy Research, three former editors first look back at: (i) the controversial persistence of the Dodo verdict (i.e., the observation that all bona fide therapies seem equally effective); (ii) the connection between process and outcome; (iii) the move toward methodological pluralism; and (iv) the politicization of the field around evidence-based practice and treatment guidelines. We then look forward to the next 25 years, suggesting that it would be promising to focus on three areas: (i) systematic theory-building research; (ii) renewed attention to fine-grained study of therapist techniques; and (iii) politically expedient research on the outcomes of marginalized or emerging therapies

Challenges to Satellite Sensors of Ocean Winds: Addressing Precipitation Effects

Measurements of global ocean surface winds made by orbiting satellite radars have provided valuable information to the oceanographic and meteorological communities since the launch of the Seasat in 1978, by the National Aeronautics and Space Administration (NASA). When Quick Scatterometer (QuikSCAT) was launched in 1999, it ushered in a new era of dual-polarized, pencil-beam, higher-resolution scatterometers for measuring the global ocean surface winds from space. A constant limitation on the full utilization of scatterometer-derived winds is the presence of isolated rain events, which affect about 7% of the observations. The vector wind sensors, the Ku-band scatterometers [NASA\u27s SeaWinds on the QuikSCAT and Midori-II platforms and Indian Space Research Organisation\u27s (ISRO\u27s) Ocean Satellite (Oceansat)-2], and the current C-band scatterometer [Advanced Wind Scatterometer (ASCAT), on the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT)\u27s Meteorological Operation (MetOp) platform] all experience rain interference, but with different characteristics. Over this past decade, broad-based research studies have sought to better understand the physics of the rain interference problem, to search for methods to bypass the problem (using rain detection, flagging, and avoidance of affected areas), and to develop techniques to improve the quality of the derived wind vectors that are adversely affected by rain. This paper reviews the state of the art in rain flagging and rain correction and describes many of these approaches, methodologies, and summarizes the results

Linear modeling of possible mechanisms for parkinson tremor generation

The power of Parkinson tremor is expressed in terms of possibly changed frequency response functions between relevant variables in the neuromuscular system. The derivation starts out from a linear loopless equivalent model of mechanisms for general tremor generation. Hypothetical changes in this model from the substrate of the disease are indicated, and possible ones are inferred from literature about experiments on patients. The result indicates that in these patients tremor appears to have been generated in loops, which did not include the brain area which in surgery usually is inactivated. For some patients in the literature, these loops could involve muscle length receptors, the static sensitivity of which may have been enlarged by pathological brain activity

Unoccupied Band Structure of NbSe2 by Very-Low-Energy Electron Diffraction: Experiment and Theory

A combined experimental and theoretical study of very-low-energy electron diffraction at the (0001) surface of 2H-NbSe2 is presented. Electron transmission spectra have been measured for energies up to 50 eV above the Fermi level with k|| varying along the GammaK line of the Brillouin zone. Ab initio calculations of the spectra have been performed with the extended linear augmented plane wave k-p method. The experimental spectra are interpreted in terms of three-dimensional one-electron band structure. Special attention is paid to the quasi-particle lifetimes: by comparing the broadening of the spectral structures in the experimental and calculated spectra the energy dependence of the optical potential Vi is determined. A sharp increase of Vi at 20 eV is detected, which is associated with a plasmon peak in the Im(-1/epsilon) function. Furthermore, the electron energy loss spectrum and the reflectivity of NbSe2 are calculated ab initio and compared with optical experiments. The obtained information on the dispersions and lifetimes of the unoccupied states is important for photoemission studies of the 3D band structure of the valence band.Comment: 17 pages, 11 Postscript figures, submitted to Phys. Rev.

Gilbert Damping in Magnetic Multilayers

We study the enhancement of the ferromagnetic relaxation rate in thin films due to the adjacent normal metal layers. Using linear response theory, we derive the dissipative torque produced by the s-d exchange interaction at the ferromagnet-normal metal interface. For a slow precession, the enhancement of Gilbert damping constant is proportional to the square of the s-d exchange constant times the zero-frequency limit of the frequency derivative of the local dynamic spin susceptibility of the normal metal at the interface. Electron-electron interactions increase the relaxation rate by the Stoner factor squared. We attribute the large anisotropic enhancements of the relaxation rate observed recently in multilayers containing palladium to this mechanism. For free electrons, the present theory compares favorably with recent spin-pumping result of Tserkovnyak et al. [Phys. Rev. Lett. \textbf{88},117601 (2002)].Comment: 1 figure, 5page

The Ethics of Corporate Governance

How should corporate directors determine what is the right decision? For at least the past 30 years the debate has raged as to whether shareholder value should take precedence over corporate social responsibility when crucial decisions arise. Directors face pressure, not least from ethical investors, to do the good thing when they seek to make the right choice. Corporate governance theory has tended to look to agency theory and the need of boards to curb excessive executive power to guide directors' decisions. While useful for those purposes, agency theory provides only limited guidance. Supplementing it with the alternatives - stakeholder theory and stewardship theory - tends to put directors in conflict with their legal obligations to work in the interests of shareholders. This paper seeks to reframe the discussion about corporate governance in terms of the ethical debate between consequential, teleological approaches to ethics and idealist, deontological ones, suggesting that directors are - for good reason - more inclined toward utilitarian judgments like those underpinning shareholder value. But the problems with shareholder value have become so great that a different framework is needed: strategic value, with an emphasis on long-term value creation judged from a decidedly utilitarian standpoint