Mach-Zehnder optical configuration with Brewster window and two quarter-wave plates

Configuration is improvement because of the following: It provides higher efficiency. It reduces or eliminates feedthrough of untranslated local oscillator, which would produce a beat signal at shifted frequency of translator. When used without translator and with low-power detector, telescope secondary mirror reflects portion of output to local oscillator

Contrasting the beam interaction characteristics of selected lasers with a partially stabilised zirconia (PSZ) bio-ceramic

Differences in the beam interaction characteristics of a CO2 laser, a Nd:YAG laser, a high power diode laser (HPDL) and an excimer laser with a partially stabilised zirconia (PSZ) bio-ceramic have been studied. A derivative of Beer-Lambert’s law was applied and the laser beam absorption lengths of the four lasers were calculated as 33.55 x 10-3 cm for the CO2 laser, 18.22 x 10-3 cm for the Nd:YAG laser, 17.17 x 10-3 cm for the HPDL and 8.41 x 10-6 cm for the excimer laser. It was determined graphically that the fluence threshold values at which significant material removal was effected by the CO2 laser, the Nd:YAG laser, the HPDL and the excimer laser were 52 J/cm2, 97 J/cm2, 115 J/cm2 and 0.48 J/cm2 respectively. The thermal loading value for the CO2 laser, the Nd:YAG laser, the HPDL and the excimer laser were calculated as being 1.55 kJ/cm3, 5.32 kJ/cm3, 6.69 kJ/cm3 and 57.04 kJ/cm3 respectively

Law’s power to safeguard global health: a Lancet–O’Neill Institute, Georgetown University Commission on Global Health and the Law

The law-–global, national, and subnational–-plays a vital, yet often underappreciated, role in safeguarding and promoting the public’s health. In this article, we launch the Lancet-O’Neill Institute, Georgetown University Commission on Global Health and the Law. Commissioners from around the world will explore the critical opportunities and challenges of using law as a tool, while evaluating the evidence base for legal interventions. The Commission aims to define and systematically describe the current landscape of law that affects global health and safety. Commissioners were chosen from disciplines that range from health, policy, and law to economics and governance. The Commission aims to present a compelling argument as to why law should be viewed as a major determinant of health and safety and how the law can be used in a powerful and innovative way to address the global burdens of injury and disease. Above all, the Commission will pursue justice, finding innovative ways to narrow existing and unconscionable health inequalitie

Simulated lumped-parameter system reduced-order adaptive control studies

Two methods of interpreting the misbehavior of reduced order adaptive controllers are discussed. The first method is based on system input-output description and the second is based on state variable description. The implementation of the single input, single output, autoregressive, moving average system is considered

Overcoming the boundary layer turbulence at Dome C: ground-layer adaptive optics versus tower

The unique atmospheric conditions present at sites such as Dome C on the Antarctic plateau are very favorable for high spatial resolution astronomy. At Dome C, the majority of the optical turbulence is confined to a 30 to 40 m thick stable boundary layer that results from the strong temperature inversion created by the heat exchange between the air and the ice-covered ground. To fully realize the potential of the exceptionally calm free atmosphere, this boundary layer must be overcome. In this article we compare the performance of two methods proposed to beat the boundary layer: mounting a telescope on a tower that physically puts it above the turbulent layer, and installing a telescope at ground level with a ground-layer adaptive optics system. A case is also made to combine these two methods to further improve the image quality

Extragalactic Radio Sources and the WMAP Cold Spot

We detect a dip of 20-45% in the surface brightness and number counts of NVSS sources smoothed to a few degrees at the location of the WMAP cold spot. The dip has structure on scales of approximately 1-10 degrees. Together with independent all-sky wavelet analyses, our results suggest that the dip in extragalactic brightness and number counts and the WMAP cold spot are physically related, i.e., that the coincidence is neither a statistical anomaly nor a WMAP foreground correction problem. If the cold spot does originate from structures at modest redshifts, as we suggest, then there is no remaining need for non-Gaussian processes at the last scattering surface of the CMB to explain the cold spot. The late integrated Sachs-Wolfe effect, already seen statistically for NVSS source counts, can now be seen to operate on a single region. To create the magnitude and angular size of the WMAP cold spot requires a ~140 Mpc radius completely empty void at z<=1 along this line of sight. This is far outside the current expectations of the concordance cosmology, and adds to the anomalies seen in the CMB.Comment: revised version, ApJ, in pres

Assessing students' learning of internal controls: Closing the loop: Working paper series--07-03

This study describes the multifaceted components of an assessment process. The paper explains a novel approach in which accounting advisory council members actively participated in a "fun," hands-on activity to rank-order learning outcomes. Understanding internal controls was the top ranked learning competency identified by the advisory council. With this competency identified, the advisory council exercise was then followed-up by a course modification in the auditing course. An empirical study, consisting of a control group and a treatment group, was then conducted to assess whether students' performance on an internal control essay question now met or exceeded established expectations. Collecting data without acting upon it is a waste of resources. This study shows how important it is to close the loop in identifying improvement opportunities

Three‐Atom Scattering in Gas‐Phase Electron Diffraction: A Tractable Limiting Case

The contribution of intramolecular multiple scattering in electron diffraction patterns of gas molecules is investigated by Glauber's method. An analytical expression for three‐atom scattering is derived for the limiting case in which the distance between atoms is large compared with atomic radii. This expression accounts well for the discrepancies between observed and conventionally calculated scattered intensities reported by Jacob and Bartell in the case of ReF6. The analogous four‐atom scattering is found to be very small.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71249/2/JCPSA6-56-5-2364-1.pd

Assessing Students Learning Of Internal Controls: Closing The Loop

This study describes the multifaceted components of an assessment process. The paper explains a novel approach in which an advisory council participated in a fun, hands-on activity to rank-order learning outcomes. The top ranked learning competency, as identified by the advisory council, was the need for students to gain a better understanding of internal controls. With this competency identified, the advisory council exercise was then followed-up by a modification in the auditing course. An empirical study, consisting of a control group and a treatment group, was conducted to assess whether performance on an internal control essay question by students now met or exceeded established expectations. The results indicated that students preliminary understanding of internal controls had been enhanced. The accounting faculty further closed the loop by approving a new internal controls course designed to cover, in greater detail, topics such as the COSO internal controls framework, Sarbanes-Oxley requirements, recent PCAOB statements, and real-world cases involving internal control failures