Plasmonic Nanoslit Array Enhanced Metal-Semiconductor-Metal Optical Detectors

Cataloged from PDF version of article.Metallic nanoslit arrays integrated on germanium metal–semiconductor–metal photodetectors show many folds of absorption enhancement for transverse-magnetic polarization in the telecommunication C-band. Such high enhancement is attributed to resonant interference of surface plasmon modes at the metal–semiconductor interface. Horizontal surface plasmon modes were reported earlier to inhibit photodetector performance. We computationally show, however, that horizontal modes enhance the efficiency of surface devices despite reducing transmitted light in the far field

Cumulative activation during positive and negative events and state anxiety predicts subsequent inertia of amygdala reactivity

Inertia, together with intensity and valence, is an important component of emotion. We tested whether positive and negative events generate lingering changes in subsequent brain responses to unrelated threat stimuli and investigated the impact of individual anxiety. We acquired fMRI data while participants watched positive or negative movie-clips and subsequently performed an unrelated task with fearful and neutral faces. We quantified changes in amygdala reactivity to fearful faces as a function of the valence of preceding movies and cumulative neural activity evoked during them. We demonstrate that amygdala responses to emotional movies spill over to subsequent processing of threat information in a valence-specific manner: negative movies enhance later amygdala activation whereas positive movies attenuate it. Critically, the magnitude of such changes is predicted by a measure of cumulative amygdala responses to the preceding positive or negative movies. These effects appear independent of overt attention, are regionally limited to amygdala, with no changes in functional connectivity. Finally, individuals with higher state anxiety displayed stronger modulation of amygdala reactivity by positive movies. These results suggest that intensity and valence of emotional events as well as anxiety levels promote local changes in amygdala sensitivity to threat, highlighting the importance of past experience in shaping future affective reactivit

Monetary Policy and Determinacy: An Inquiry in Open Economy New Keynesian Framework

We analyze determinacy in the baseline open-economy New Keynesian model developed by Gali and Monacelli (2005). We find that the open economy structure causes multifaceted behaviors in the system creating extra challenges for policy making. The degree of openness significantly affects determinacy properties of equilibrium under various forms and timing of monetary policy rules. Conditions for the uniqueness and local stability of equilibria are established. Determinacy diagrams are constructed to display the regions of unique and multiple equilibria. Numerical analyses are performed to confirm the theoretical results. Limit cycles and periodic behaviors are possible, but in some cases only for unrealistic parameter settings. Complex structures of open economies require rigorous policy design to achieve optimality

Hopf bifurcation in the Clarida, Gali, and Gertler model

We explore bifurcation phenomena in the open-economy New Keynesian model developed by Clarida, Gali and Gertler (2002). We find that the open economy framework can bring about more complex dynamics, along with a wider variety of qualitative behaviors and policy responses. Introducing parameters related to the open economy structure affects the values of bifurcation parameters and changes the location of bifurcation boundaries. As a result, the stratification of the confidence region, as previously seen in closed-economy New Keynesian models, remains an important research and policy risk to be considered in the context of the open-economy New Keynesian functional structures. In fact, econometrics and optimal policy design become more complex within an open economy. Dynamical inferences need to be qualified by the risk of bifurcation boundaries crossing the confidence regions. Without adequate prior econometric research, policy design needs to take into consideration that a change in monetary policy can produce an unanticipated bifurcation

An analytical and numerical search for bifurcations in open economy New Keynesian models

We explore bifurcation phenomena in the open-economy New Keynesian model developed by Gali and Monacelli (2005). We find that the open economy framework brings about more complex dynamics, along with a wider variety of qualitative behaviors and policy responses. Introducing parameters related to the open economy structure affects the values of bifurcation parameters and changes the location of bifurcation boundaries. As a result, the stratification of the confidence region, as previously seen in closed-economy New Keynesian models, remains an important research and policy risk to be considered in the context of the open-economy New Keynesian functional structures. In fact, econometrics and optimal policy design become more complex within an open economy. Dynamical inferences need to be qualified by the risk of bifurcation boundaries crossing the confidence regions. Policy design needs to take into consideration that a change in monetary policy can produce an unanticipated bifurcation, without adequate prior econometrics research

The diagnostic value of adenosine deaminase activity in sputum in pulmonary tuberculosis

AbstractThis study was carried out in Atatürk Chest Diseases and Surgery Center. It's aim to determine and compare sputum adenosine deaminase (ADA) activity in pulmonary tuberculosis (tb), lung cancer and chronic obstructive pulmonary disease (COPD) patients in order to assess its diagnostic value. Patients and method: Eighty-four patients (25 tb, 30 lung cancer and 29 COPD) were included in the study. ADA activity in sputum and serum was measured. Sputum ADA activities of tb patients were significantly higher than the other two groups (P<0.05). Sputum/serum ADA ratios were similar in all groups. Sputum ADA activities between 150 and 200 U/L were the measurements with the best test performance according to the ROC curve. Sensitivity, specificity, positive predictive value, and negative predictive value were 44.0, 86.4, 57.8, 78.4% for 150 U/L and 32.0, 96.6, 80.0, 77.0% for 200 U/L, respectively. Area under the curve was 0.663. Because of low sensitivity, routine determination of ADA activity in sputum for the diagnosis of pulmonary tb is not recommended. However, it can be helpful in the diagnosis of smear-negative cases who are strongly suspected of tb

Plasmonic nanoslit array enhanced metal-semiconductor-metal optical detectors

Metallic nanoslit arrays integrated on germanium metal-semiconductor-metal photodetectors show many folds of absorption enhancement for transverse-magnetic polarization in the telecommunication C-band. Such high enhancement is attributed to resonant interference of surface plasmon modes at the metal-semiconductor interface. Horizontal surface plasmon modes were reported earlier to inhibit photodetector performance. We computationally show, however, that horizontal modes enhance the efficiency of surface devices despite reducing transmitted light in the far field. © 2006 IEEE