Photon statistics of single-mode zeros and ones from an erbium-doped fiber amplifier measured by means of homodyne tomography

We report measurement of the photon-number distributions of zeros and ones that emerge from an erbium-doped fiber amplifier (EDFA) in an on-off modulated communication system. Single-mode single-photon resolution was achieved by employing the method of optical homodyne tomography. The measured distributions agree with the quantum predictions of a Bose-Einstein distribution for the zeros and a Laguerre (noncentral negative binomial) distribution for the ones over a dynamic range up to 40 dB. The resulting noise figure of the amplifier compares well to that measured by an optical spectrum analyzer.     

A description and the measured performance of three coaxial beam-rotating antenna prototypes

Many high-power microwave (HPM) sources utilize an azimuthally symmetric output mode, like the TM/sub 01/ circular waveguide or the coaxial TEM modes. If radiated directly, these modes produce a doughnut-shaped radiation pattern, with a boresight . Mode-conversion techniques for transforming the azimuthally symmetric mode to one with a more desirable radiated pattern are possible, but mode conversion is typically undesirable, due to inefficiencies and due to increases in system size and weight. Antenna designs have been explored that will radiate the azimuthally symmetric mode directly, but those considered to date tend to exhibit low gain, and do not radiate a boresight peak (along the longitudinal axis of the source). This article describes the measured performance of three prototype antennas, all of the coaxial beam-rotating antenna (COBRA) class. These accept directly an azimuthally symmetric mode, and radiate a high-gain, circularly polarized beam with a boresight peak. The antennas achieve this capability by varying the electrical length of a path from a focal point to the aperture plane as a function of the azimuthal angle of the aperture. A brief overview of the general theory of COBRA operation is first presented. Next, measured data, characteristic of the input impedance and far-field patterns of three COBRA prototypes, are given. The architectures of COBRA prototypes reviewed in this article include those utilizing (1) a single, stepped paraboloidal reflector; (2) a dual reflector; and (3) a dual reflector with a coaxial feed.     

"Treating traumatized OEF/OIF veterans: How does trauma treament affect the clinician?": Correction to Voss Horrell et al. (2011).

Reports an error in "Treating traumatized OEF/OIF veterans: How does trauma treatment affect the clinician" by Sarah C. Voss Horrell, Dana R. Holohan, Lea M. Didion and G. Todd Vance (Professional Psychology: Research and Practice, 2011[Feb], Vol 42[1], 79-86). The word “While” was erroneously inserted in the first sentence of the “Clinician Factors” section. The corrected sentence is provided in the erratum. (The following abstract of the original article appeared in record 2011-04544-011.) The authors of this article describe the rewards and challenges for clinicians treating veterans who have served in Operation Enduring Freedom (OEF) and Operation Iraqi Freedom (OIF). Issues of vicarious trauma, secondary traumatic stress, compassion fatigue, and burnout are defined and reviewed, as are compassion satisfaction and posttraumatic growth. Patient, clinician, and organizational characteristics that are likely to affect clinicians working with this clinical population are discussed. Patient factors that may increase strain on clinicians are discussed such as age, likelihood of redeployment, comorbid conditions, attendance issues, and elevated risk for suicide and aggression. Clinician factors, such as theoretical orientation, training, supervision, military affiliation, personal trauma history, spirituality, social support, and self-care, are also discussed as possible risk and protective factors for vicarious trauma and burnout. Organizational influences, such as caseload size and diversity, clinician control and autonomy, use of evidence-based practices, availability of resources, rural isolation, and the philosophy of the clinic, are further discussed. Recommendations for ameliorating risks are discussed relative to each area and include allowing clinicians to plan their own appointments so as to balance their caseload of OEF/OIF veterans, attending to self-care practices, and having a supportive team with thorough training in evidence-based practices. Future empirical research is needed on risk and resiliency factors for clinicians working with traumatized OEF/OIF veterans given that this population is likely to grow. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

A computer-assisted system for reconstructing and interpreting the dynamic three-dimensional relationships of the outer surface, nucleus and pseudopods of crawling cells

Newly developed software additions to the three-dimensional dynamic image analysis system, 3D-DIAS, are described for simultaneously reconstructing and motion analyzing in three dimensions the outer surface, nucleus and pseudopods of living, crawling cells. This new system is then used to describe for the first time a nuclear behavior cycle in translocating Dictyostelium discoideum amoebae and to investigate the role of pseudopod extension in this process. The nuclear behavior cycle is tuned to the two phases of the general cell behavior cycle [Wessels et al., 1994], and includes nuclear migration both in the z- and in the x,y-axes from the proximal border of the prior anterior pseudopod to the proximal border of a newly expanding anterior pseudopod. Nuclear migration is cued by pseudopod-substratum contact, achieves velocities in excess of 50 microm/min, and is accompanied by characteristic changes in nuclear shape. The rules and characteristics of nuclear behavior are demonstrated to be intact in two mutants affecting pseudopod formation, a myosin IB null mutant (myoB-) and a myosin II heavy chain phosphorylation mutant (3XALA). The rules and characteristics of nuclear migration, however, are disrupted upon dissolution of microtubules by colcemid. Together the above results demonstrate that the newly developed 3D-DIAS system can be used to gain new insights into the dynamic changes in the intracellular 3D architecture associated with cellular translocation.     

Energy efficient office buildings with passive cooling – Results and experiences from a research and demonstration programme

To gain access to information on energy use in office buildings, the German Federal Ministry for Economy launched an intensive research and demonstration programme in 1995. In advance of the 2002 EU energy performance directive a limited primary energy coefficient of about 100 kW h m⁻² a⁻¹ as a goal for the complete building services technology was postulated (HVAC + lighting) for all demonstration buildings to be supported. A further condition was that active cooling be avoided. Techniques such as natural or mechanical night ventilation or heat removal by slab cooling with vertical ground pipes as well as earth-to-air heat exchangers in the ventilation system were applied. An accompanying research was established to keep track of the results and the lessons learned from about 22 demonstration buildings realized and monitored until the end of 2005. As one outcome this paper summarises the energy performance of a selection of characteristic buildings together with an overview on the summer thermal comfort situations achieved. The research program will proceed during the next five years. Detailed reports and future results may be downloaded from the internet: www.enbau-monitor.de.     

Correlation of functional independence measure (FIM) and SPECT Iofetamine (I-123) as a predictor of functional return in stroke

Murine embryonic stem (ES) cells have been a useful model system for the study of various aspects of hematopoietic differentiation. Because we had observed a sharp peak of expression of the receptor tyrosine phosphatase gamma (Ptp gamma) gene between 14 and 18 days of ES-derived embryoid body differentiation, we investigated the effect of perturbation of expression of the Ptp gamma gene on ES cell differentiation, first by analyzing the effect of Ptp gamma overexpression. The murine full-length Ptp gamma cDNA in an expression vector was transfected into ES-D3 cells and stably transfected clones were isolated. Ptp gamma was expressed as an approximately 230-kD cell surface protein, and differentiating ES clones that overexpressed Ptp gamma gave rise to a normal number of hematopoietic colonies, approximately 1 CFU per 100 cells. There was, however, a significant increase of expression of early hematopoietic markers in colonies from Ptp gamma overexpressing ES cells. To confirm that the pertubation of hematopoietic differentiation was a result of Ptp gamma overexpression, we isolated ES stem cell clones expressing Ptp gamma antisense constructs and assayed embryoid bodies for the presence of hematopoietic precursors. We observed a complete absence of methylcellulose colonies, indicating absence of hematopoietic lineages. Results of these experiments point to an essential role for Ptp gamma in hematopoietic differentiation.     

Removal and transfer of material in laser-assisted physical vapour deposition of ceramics

The removal and transfer of ceramic target materials in laser-assited physical vapour deposition are investigated as a function of laser parameters and processing variables. Removal was measured by a microbalance and characteristics of angular distribution, transfer by emission spectroscopy and high-speed photography. The composition, the ionization state of the particles and the electron temperature of the vapour/plasma govern the structures of the thin films deposited, which are discussed in view of applications.