Search

The non-harmonic input voltage waveform becomes more frequent with the increasing interest in the multiphase machines; the injecting of higher harmonics is used to the decrease of the saturation of the machine. The non-harmonic flux linkage waveform affects the total iron losses. Presented paper deals with the usage of the modified Steinmetz equation (MSE) used to the calculation of the iron losses. The analytical-numerical tool including the nonlinearity of the magnetic circuit and the dynamic BH curve is presented. Different configurations of input voltage and magnetic material properties are analyzed and the results are compared with the analytical calculation and finite element analysis.

Purpose The purpose of this study is to explore the regulatory framework in China and the extent to which Chinese multinationals have implemented and disclosed their anti-bribery and corruption (ABC) compliance practices. This is done against the backdrop of the evolving international ABC compliance standards. Design/methodology/approach This study is based on detailed reviews of the ABC compliance standards of international organizations; legislation passed by the USA, the UK and Chinese Governments; seven semi-structured interviews with leading experts in the field; and comparisons of ABC program disclosures of four Chinese with four best-in-class western multinational corporations. Findings A high level of convergence was found in the ABC standards published by the international organizations. Several positive features were found in the Chinese ABC regulatory frameworks but our findings indicate that there is minimal disclosure around ABC compliance program practices. This paper shows that a transparent disclosure would represent an easy win for Chinese multinational corporations and contribute to raising their reputations internationally. Research limitations/implications While there are numerous studies in the law literature on ABC compliance standards and the extent to which they are effective in achieving their objectives, this is an emergent area in management research, to which our study makes a contribution. Future research could explore how other emerging economies are tackling this important issue. Practical implications By proactively adopting ABC compliance practices, corporations can seize the ethical high ground and build solid reputations with their stakeholders. Originality/value It is believed that this study is the first academic study that compares Chinese and international ABC standards.

Background: There is increasing speculation that diet has an important impact on mental health and that the outcomes of certain mental health disorders, including depression may be influenced by nutritional factors. Although considerable research has focused on understanding the biochemistry and assessing the efficacy of pharmaceutical interventions for depression, it is only recently that research attention has focused on the impact of diet. Emerging evidence suggests that certain nutrients may be important in the pathogenesis and treatment of depression.Aims: This review seeks to establish the current evidence base supporting nutritional interventions in unipolar depression.Methods: Literature searches identified articles relating to nutritional supplementation in unipolar depression. These were subdivided into categories. All randomized controlled trials were graded using SIGN 50 criteria, with an overall grading recommendation assigned to the evidence for each nutrient.Results: Ten randomized controll...

Safety-critical systems have to satisfy ever-growing demands for high computing performance and cost-efficiency. This leads to a move to commercial off-the-shelf hardware components that are not hardened. Unfortunately, these components are becoming increasingly vulnerable to operational faults and the manufacturers do not guarantee a certain level of dependability. However, in order to maintain a high integrity, safety-critical systems have to ensure the correct functionality of hardware components during operation. Besides redundancy techniques, this is typically realized with build-in self-tests implemented at software level. Safety-standards, such as the IEC 61508 standard, prescribe certain fault models that should be used to assess the diagnostic coverage of self-tests with fault injection experiments. Typical fault injection frameworks use gate-level net lists or RTL models. However, these hardware models are not publicly available for most COTS processors. In this paper we present a Fault Injection framework for the Evaluation of software-based Self-tests (FIES) according to the safety standard IEC 61508. This virtual platform supports widely-used embedded COTS processors, such as ARM cores, and provides feedback about the diagnostic coverage of self-tests in early design stages. It supports the simulation of faults in the control and execution path of an ARM processor and features an extended fault model to simulate memory coupling faults. The applicability of the approach is shown by using it for the evaluation of a memory test.

We have investigated the MeV behaviour of the \gray blazars 3C~454.3 and CTA 102 by analyzing all COMPTEL observations of this sky region during the complete CGRO mission. Both sources are detected by COMPTEL at the upper COMPTEL energies; although their flux estimates may be uncertain by possible minor contribution of nearby unidentified EGRET \gray sources. While CTA 102 was only detected at energies above 10 MeV during the early mission, 3C~454.3 is most significantly detected in the COMPTEL 3-10 MeV band in the sum of all data. Time-resolved analyses indicate a weak (near COMPTEL threshold) but likely steady 3-10 MeV emission over years, being independent of the observed time variability at energies above 100 MeV as observed by EGRET. This energy-dependent variability behaviour suggests different emission mechanisms at work at the two bands. Putting the COMPTEL fluxes in multifrequency perspective (radio to \grays), reveals for both sources the typical two-hump blazar spectra, with a low-energy maximum around the IR and a high-energy maximum at MeV energies. The latter one dominates the energy output across the whole electro-magnetic spectrum. The results of our analyses are discussed in the framework of current blazar modeling., Comment: 19 pages, 11 figures, accepted for publication in A&A

A high dynamic range (HDR) CMOS image sensor architecture based on spiking pixel cells and its first implementation, a linear 128-pixel sensor, is presented. The pulse rate of the pixel cell is proportional to the local light intensity. The pixel cell features a pixel-level analog-to-digital (A/D) conversion by pulse counting. It allows one to tradeoff conversion precision versus frame rate. Sample sensor chips have been manufactured using a 0.8-/spl mu/m double metal CMOS technology, and the test results confirming the feasibility of the chosen approach are reported.

Background: In spite of significant progress in the outcome of multiple myeloma (MM), effective treatment options are still missing for high-risk patients. A better understanding of key mechanisms in high-risk disease is therefore a necessary prerequisite for the development of novel therapeutic options for patients with poor prognosis. Here, we evaluated maternal embryonic leucine zipper kinase (MELK) for its implications in the prognosis of MM, its interactions with genes involved in high-risk MM and the impact of MELK inhibition in vitro and in vivo. Methods: Expression levels of genes associated with high-risk MM were analyzed in two large cohorts of publically available gene expression (GEP) datasets (GSE2658 and GSE9782; n=551 and n=264, respectively) and by quantitative PCR (qPCR) in human myeloma cell lines (HMCLs). The impact of MELK inhibition was studied using a selective inhibitor of MELK (OTSSP167). MELK and OTSSP167 target genes were analyzed by qPCR and Western Blot. MELK knockdown HMCLs were generated via lentiviral transduction of MELK specific shRNA. For the in vivo experiment, C57BL/KaLwRij mice were injected intravenously with 5x105 GFP-transfected 5TGM.1 cells. Starting the day after injection, two groups of mice were treated by different doses of OTSSP167 (15mg/kg/d or 7.5mg/kg/2d) and one group received the vehicle. Treatment was administered orally. Results: MELK expression was significantly elevated in the GEP-defined high-risk proliferation (PR) associated molecular subgroup compared to healthy donor bone marrow plasma cells, but barely detected in any other GEP defined MM subgroup. Consequently, overall survival was significantly shorter in patients with high compared to low MELK levels treated within the total therapy 2 (P=0.0003), total therapy 3 (P=0.04) and the APEX trial protocol (P=0.002). Of note, MELK expression was further elevated in relapsed patients compared to baseline (GSE31161) suggesting a potential role in drug resistance. In line with their proliferative character, MELK expression was detected in 8 of 8 HMCLs. Treatment with the MELK inhibitor OTSSP167 downregulated MELK protein levels and led to a dose-dependent reduction of viability in all primary MM samples and HMCLs tested (median IC50: 10.16 nM, range: 7.6 - 15.2 nM). We observed induction of apoptosis in all HMCLs investigated, verified by mitochondrial membrane depolarization, annexin V/7-AAD staining, detection of cleaved caspase 3, and cleaved PARP. This was accompanied by downregulation of gene expression levels of IRF4 and MCL-1. In addition, OTSSP167 induced a G2/M cell cycle arrest which was linked to downregulation of cyclin B1, aurora kinase A and PLK-1. Importantly, we also observed reduced clonogenic growth of MM cells treated with OTSSP167 and the anti-myeloma activity of OTSSP167 was upheld in the presence of bone marrow stromal cells. We next sought to clarify the impact of MELK on other genes implicated in high-risk myeloma. Strikingly, treatment of HMCLs with OTSSP167 reduced MELK and PLK-1 protein levels, but also those of FOXM1, EZH2 and DEPDC1. This relationship was confirmed in HMCLs with shRNA mediated MELK knockdown. All of these genes were significantly elevated in the GEP defined PR subgroup and associated with poor outcome. Finally, the activity of OTSSP167 was analyzed in the 5TGM.1 model of MM. In vivo, we observed a dose-dependent reduction of tumor parameters by OTSSP167. Low doses of OTSSP167 significantly reduced spleen weight and serum IgG2b levels but only tended to decrease BM infiltration, while high doses of OTSSP167 significantly decreased tumor infiltration analyzed by spleen weight (267mg vs 108mg) and bone marrow infiltration (14% vs 2%, P Conclusion: The current study identified almost exclusive expression of MELK in the GEP defined PR subgroup of MM. Hence, MELK expression represents a novel poor prognostic marker. Inhibition of MELK with OTSSP167 impaired myeloma cell growth and survival in vitro and in vivo. Moreover, downregulation of MELK via shRNA or OTSSP167 treatment significantly reduced protein levels of several other genes of the GEP defined PR subgroup of myeloma, suggesting a central role for MELK in the signaling network of proliferation associated high-risk myeloma. These results place MELK in the center of a MM high-risk gene network and emphasize to initiate clinical testing of MELK inhibition in MM. Disclosures Ludwig: Amgen: Research Funding, Speakers Bureau; Janssen: Speakers Bureau; Bristol-Myers Squibb: Speakers Bureau; Takeda: Research Funding, Speakers Bureau.

A personal view of the major technical deficiencies of Fortran 90 is presented. The defects are listed and described in what might be interpreted as a set of requirements for a future language revision. The list reflects the view of one of the active designers of Fortran 90 and one who is the head of a major academic computing service whose users are slowly becoming significant users of Fortran 90. The views are therefore conditioned both by individual observations and by the observed reactions of users starting to use Fortran 90 in anger.

We present results from In/sub 0.35/Ca/sub 0.65/As-GaAs 4 QW lasers whose Al/sub 0.8/Ga/sub 0.2/As binary short-period superlattice (SPSL) cladding layers were grown at either 700/spl deg/C or 620/spl deg/C. The threshold current densities (J/sub th/) are /spl sim/3 times smaller for the lasers whose AlGaAs cladding layers were grown at 620/spl deg/C. At the same time, the internal differential quantum efficiency (/spl eta//sub i/) increases from 60% to 70%. We attribute the lower J/sub th/ and increased /spl eta//sub i/ to a significant decrease in the concentration of point defects in the MQW active region, consistent with the observed improvement of the diode ideality factor. Temperature-dependent photoluminescence (PL) results suggest that these nonradiative recombination centers are related to point defects recently observed with Raman scattering. Ridge lasers grown with low-temperature SPSL Al/sub x/Ga/sub 1-x/As have achieved 3-dB modulation bandwidths of 24 GHz at record low bias currents of only 25 mA. >

We present a systematic theoretical investigation of the influence of p-doping on the gain characteristics of strained In/sub 0.35/Ga/sub 0.65/As/GaAs multiple-quantum-well (MQW) lasers, and compare the results with those obtained experimentally from devices with record 30 GHz modulation bandwidths. Experimentally, the combination of p-doping and strain has been found to lead to only a small increase in the differential gain, /spl part/g//spl part/n, but a large decrease in the non-linear gain coefficient, /spl epsiv/; this behaviour has been theoretically accounted for by a doping-induced decrease in the intraband relaxation time, /spl tau//sub in/. The theoretical investigations reveal that the assumption of a constant intraband relaxation time is not sufficient to describe the role of p-doping in the above devices, and highlight the importance of utilizing an appropriate lineshape function for the modeling of high speed laser modulation behaviour. >

Observations (Leroy, 1985) have shown that most large, high prominences are of the inverse polarity type, in that the magnetic field passes through the prominence in the inverse direction to that expected from the observed photospheric field. The classic inverse polarity model of Kuperus and Raadu (1974) assumed that the prominence lies below a region of closed magnetic field lines in the neighbourhood of an O-type neutral point and above an X-type neutral point. Since the prominence must form in a low-βcoronal plasma, the pre-prominence magnetic field must have the correct topology for an inverse polarity configuration. In this paper a wide variety of different current profiles are considered in the Grad-Shafranov equation that is used to describe the equilibrium. The results of numerical solutions to the equilibrium equation indicate that a fully developed prominence will possess an O-type, but not in general an X-type neutral point.

In the attempts to attain greater efficiency of mobility, based in the long-term on renewable energy sources, the efficiency of energy conversion in the vehicle remains an important issue. Polymer electrolyte membrane fuel cell technology has the potential to improve the efficiency of the powertrain for passenger vehicles above the level of present internal combustion engine solutions in relevant operation areas. Several questions need still to be solved to verify this potential superiority under the conditions of daily vehicle operation. Therefore, new materials have to be developed for improved component performance at lower cost and for more complicated environmental conditions. The effect of these specifications on the efficiency potential of the fuel cell system is open to debate. Another target is the performance of advanced powertrains based on internal combustion engines, which are in competition with the fuel cell system.

We report research on the characterization of stresses in relation to defects in multicrystalline silicon (mc-Si) solar cell material. Photoelasticity and micro-Raman spectroscopy (μRS) techniques are combined to understand this correlation at different length scales. While photoelasticity can probe small residual thermal stresses distributed over the entire volume of the sample as well as local stresses caused by defects, μRS can measure very localized intrinsic stresses of defects existing at the sample surface. Defects such as dislocations and inclusions are usually accompanied by stresses. In combination with thermal stresses, it results in a global residual stress state in the material. Thermal stresses are induced by the mismatch of different coefficients of thermal expansion between inclusions and silicon as well as due to local inhomogeneous temperature gradients during crystallization. Thermal stresses that relax by forming efficiency limiting defects can be reduced below the yield stress values by optimizing the crystallization conditions using photoelasticity.

This International Standard has been prepared by ISO/IEC JTC1/SC22/WG5, the technical working group for the Fortran language. This International Standard is a collateral standard to ISO/IEC 1539:1991, which defines the latest revision of the Fortran language, known informally as Fortran 90.

A substantially modified Draft Proposal for a revised ISO Fortran Standard (ISO DP-1539) has recently been subjected to a second round of public review and voting by National Standards bodies. The language as defined does not provide intrinsic support for dynamically sized character strings. In common with Ada, Fortran has chosen to consider these as a facility that is better provided as a semantic extension. In Fortran's case, this is achieved by use of a suitably designed MODULE; the analogue in Fortran of the Ada package. ISO has, in fact, requested that a suitable module be designed and adopted as a collateral standard. This paper looks at a possible design for such a module. It illustrates how facilities in the revised Fortran can be exploited to provide very different implementation which nevertheless have identical functionality and user interface. The facilities of Fortran for hiding the details of the implementations are exploited in such a way that an application employing such a module would be entirely unaffected by which version was actually used, except perhaps for its speed of execution

The market share of thin semiconductors has continuously increased in microelectronical, micromechanical as well as in the solar industries in the recent years, e.g. due to required flexibility for RFIDs or cost reduction of solar cells. However thin wafers are difficult to handle, because of the increasing flexibility and increasing sensitivity to mechanical, thermal and intrinsic loads in manufacturing and use. Therefore the mechanical properties, especially strength, have to be investigated in order to optimize manufacturing steps with regard to the reliability. In the semiconductor industry one can find a lot of reports about the decreasing strength of thin silicon devices. The small thickness seems to be responsible for early fracture in manufacturing. In this work, the strength of thin silicon is investigated. For the investigation (3times3)mm2-dies with a thickness between 200mum and 48mum made from (100) single crystalline silicon were investigated using the ball on ring test. All specimens were thinned back by grinding and wet-chemical spin-etching for stress relief. The front side was not treated by an additional process. In ball on ring tests the maximum principle stress occurs at the surface at the center of the specimen. Since the stress at the edge of the sample is significantly smaller than the stress at the sample center the fracture starts in the center of the sample. Thus the influence of the back thinning technology can be characterized and the dicing process does not influence the test results. For statistical evaluation 40 specimen of each thickness were tested. The front side was also tested as reference. Weibull theory, based on the weakest link model, was chosen for statistical evaluation. Due to the small thicknesses of the samples the force-displacement curves show a nonlinear relationship. Hence the finite element method in consideration of large deflection (geometric nonlinearity) was applied to calculate the fracture stress from the fracture force of each specimen. Additional the contact behavior (structural nonlinearity) between ball and specimen was modeled to consider the changing boundary conditions in large deflection. The influence of the chip thickness on the characteristic fracture stress is shown. It can be seen, that the strength is increasing with decreasing sample thickness for both front and back side. The fracture stress increases very strongly in the range of 50...100mum. It has to be kept in mind that all samples were treated with same process steps. Thus it can be assumed that all samples show the same flaw size and flaw distribution. Hence it can be concluded, that the strength of identical manufactured samples depends on the sample thickness for small thicknesses. In the case of very small sample thickness (less than 20mum), some specimen showed buckling in ball on ring test, caused by large deflection. In order to derive reliable stress values in numerical calculation this process of instability has to be investigated. With the results guidelines can be given for reliable ball on ring testing of thin silicon samples. The influence of the thickness of silicon dies on the strength properties as well as challenges in testing are the focus of further investigations

According to standard models supernovae produce radioactive $^{44}$Ti, which should be visible in gamma-rays following decay to $^{44}$Ca for a few centuries. $^{44}Ti production is believed to be the source of cosmic $^{44}$Ca, whose abundance is well established. Yet, gamma-ray telescopes have not seen the expected young remnants of core collapse events. The $^{44}$Ti mean life of $\tau \simeq$ 89 y and the Galactic supernova rate of $\simeq$ 3/100 y imply $\simeq$ several detectable $^{44}Ti gamma-ray sources, but only one is clearly seen, the 340-year-old Cas A SNR. Furthermore, supernovae which produce much $^{44}Ti are expected to occur primarily in the inner part of the Galaxy, where young massive stars are most abundant. Because the Galaxy is transparent to gamma-rays, this should be the dominant location of expected gamma-ray sources. Yet the Cas A SNR as the only one source is located far from the inner Galaxy (at longitude 112 degree). We evaluate the surprising absence of detectable supernovae from the past three centuries. We discuss whether our understanding of SN explosions, their $^{44}Ti yields, their spatial distributions, and statistical arguments can be stretched so that this apparent disagreement may be accommodated within reasonable expectations, or if we have to revise some or all of the above aspects to bring expectations in agreement with the observations. We conclude that either core collapse supernovae have been improbably rare in the Galaxy during the past few centuries, or $^{44}Ti-producing supernovae are atypical supernovae. We also present a new argument based on $^{44}$Ca/$^{40}$Ca ratios in mainstream SiC stardust grains that may cast doubt on massive-He-cap Type I supernovae as the source of most galactic $^{44}$Ca., Comment: 23 pages, 14 figures, accepted for publication in Astronomy and Astrophysics 2006. Correcting the SN type of Tycho in Table B.1. and add its associated references

Thin silicon offers a variety of new possibilities in microelectronical and micromechanical industries, e.g. for 3D-integration (stacked dice) or optoelectronic components (LED). The thin wafers are fabricated by back thinning technologies like grinding, polishing or etching and diced into single chips. The separation technologies can be coupled with back thinning technologies (dicing-by-thinning) to increase the reliability and strength of dies. In order to characterize and optimize relevant process steps in terms of quality and fabrication yield, also the mechanical properties have to be investigated with respect to defect formation and strength. In this paper three different dicing technologies were characterized by 3-point bending tests. The first technology is a common sawing process. The second and third technology are "dicing-by-thinning" processes, one with sawn grooves and the other with dry-etched trenches. In addition to the experimental investigations, analytical and numerical calculations were performed in order to understand the nonlinear relationship of force and displacement and to calculate fracture stresses from fracture forces. The results were statistical evaluated by the Weibull theory. Using this approach allows a more comprehensive understanding of the influence of the process on strength properties independently of geometric factors. In particular, it forms a base to predict the strength determined from tests for real devices and to quantify the potential of strength increase by using improved technologies, such as Dicing-by-Thinning. It was shown in this paper, that the nonlinear relationship of force and displacement can be described and explained. Thus the fracture stress as parameter of strength could be calculated for all tested samples. Samples, being separated by "dicing-by-thinning", have much higher strength than simply sawed samples. If trenches are made by dry-etched process the strength can be increased tremendously.

In this paper, the realization and characterization of a microoptical sensor using the chromatic confocal principle is presented. The sensor head is designed for distance gauging applications in high aspect ratio cavities with a diameter of about 2 mm. The first part of this paper focuses on the design and fabrication process of the hybrid optical benches, which combines refractive and diffractive micro optical components. Very tight tolerances of the optical path are required for the functionality of the sensor. Therefore the alignment structures and mounts between the different optical elements are produced from PMMA using deep X-ray lithography, the first step of the LIGA process. In the second part of this paper the characterization of first prototypes using different light sources are described and results presented.

The carrier lifetime in undoped and p‐doped mesa and ridge waveguide In0.35Ga0.65As/GaAs multiple‐quantum‐well lasers is extracted from the frequency response of the spontaneous emission. The radiative recombination coefficient is found to be the same for mesa and ridge waveguide lasers, and is nearly independent of the doping level. For ridge waveguide lasers, a simple method is proposed to obtain the lateral broadening of the active region due to carrier diffusion. When the corrected active region width is considered, the threshold carrier densities for both undoped and p‐doped lasers are independent of the lateral structure and cavity width. Further, the surface recombination velocity in mesa lasers is determined.

We demonstrate record direct modulation bandwidths from MBE-grown In/sub 0.35/Ga/sub 0.65/As-GaAs multiple-quantum-well lasers with undoped active regions and with the upper and lower cladding layers grown at different growth temperatures. Short-cavity ridge waveguide lasers achieve CW direct modulation bandwidths up to 40 GHz for 6/spl times/130 /spl mu/m/sup 2/ devices at a bias current of 155 mA, which is the damping limit for this structure. We further demonstrate large-signal digital modulation up to 20 Gb/s (limited by the measurement setup) and linewidth enhancement factors of 1.4 at the lasing wavelength at threshold of /spl sim/1.1 /spl mu/m for these devices.

The carrier profile for MBE grown In0.35Ga0.65As/GaAs multiquantum well laser structures with nominally undoped and beryllium‐doped active regions was determined by using the capacitance–voltage (C–V) technique at room temperature. A simple theoretical model was used to extract the impurity concentration and the quantum‐well carrier density from the experimental profiles. We obtained a high carrier concentration in nominally undoped devices caused by a strong growth temperature dependent Be diffusion from the p‐cladding layer, and no difference between doped samples with different nominal dopant location.

The center of our Galaxy is a known strong source of electron-positron 511-keV annihilation radiation. Thus far, however, there have been no reliable detections of annihilation radiation outside of the central radian of our Galaxy. One of the primary objectives of the INTEGRAL (INTErnational Gamma-RAy Astrophysics Laboratory) mission, launched in Oct. 2002, is the detailed study of this radiation. The Spectrometer on INTEGRAL (SPI) is a high resolution coded-aperture gamma-ray telescope with an unprecedented combination of sensitivity, angular resolution and energy resolution. We report results from the first 10 months of observation. During this period a significant fraction of the observing time was spent in or near the Galactic Plane. No positive annihilation flux was detected outside of the central region (|l| > 40 deg) of our Galaxy. In this paper we describe the observations and data analysis methods and give limits on the 511-keV flux., Accepted for publication in the Astrophysical Journal. 13 pages, 3 figures

The search for gamma-ray line emission from the radioactive decay of 60Fe figures among the prime scientific objectives of the INTEGRAL mission. 60Fe is believed to be primarily produced in core-collapse supernovae, although other sites, such as carbon deflagration supernovae or intermediate mass AGB stars have also been suggested. We present first results of our search for the 1173 and 1332 keV gamma-ray lines of 60Fe decay in the SPI data of the first mission year. So far we can only report upper flux limits whose levels are determined by systematic uncertainties in the treatment of the instrumental background. Once we understand the background uncertainties better, the SPI data should provide stringent constraints on 60Fe nucleosynthesis in our Galaxy., Comment: 5 pages, to appear in the Proceedings of the 5th INTEGRAL Workshop (Munich, Germany)

We provide first constraints on the morphology of the 511 keV line emission from the galactic centre region on basis of data taken with the spectrometer SPI on the INTEGRAL gamma-ray observatory. The data suggest an azimuthally symmetric galactic bulge component with FWHM of ~9deg with a 2sigma uncertainty range covering 6deg-18deg. The 511 keV line flux in the bulge component amounts to 9.9(+4.7;-2.1) x 10-4 ph cm-2 s-1. No evidence for a galactic disk component has been found so far; upper 2sigma flux limits in the range (1.4-3.4) x 10-3 ph cm-2 s-1 have been obtained that depend on the assumed disk morphology. These limits correspond to lower limits on the bulge-to-disk ratio of 0.3-0.6. Based on observations with INTEGRAL, an ESA project with instruments and science data centre funded by ESA member states (especially the PI countries: Denmark, France, Germany, Italy, Switzerland, Spain), Czech Republic and Poland, and with the participation of Russia and the USA.

In its space environment the INTEGRAL observatory is subject to an intense irradiation by energetic cosmic-ray particles that leads, via nuclear interactions with the telescope and spacecraft materials, to an important background of false events. In this paper we present the characteristics of the instrumental background that is observed in the spectrometer SPI (SPectrometer of INTEGRAL). We explain the tuning that has been performed on the parameters of the anticoincidence system in order to optimise the telescope sensitivity over the full energy range. Temporal variations of the instrumental background are discussed and methods are proposed that allow for their modelling in first order. Based on observations with INTEGRAL, an ESA project with instruments and science data centre funded by ESA member states (especially the PI countries: Denmark, France, Germany, Italy, Switzerland, Spain), Czech Republic and Poland, and with the participation of Russia and the USA.

SPI is a high spectral resolution gamma-ray telescope on board the ESA mission INTEGRAL (International Gamma Ray Astrophysics Laboratory). It consists of an array of 19 closely packed germanium detectors surrounded by an active anticoincidence shield of BGO. The imaging capabilities of the instrument are obtained with a tungsten coded aperture mask located 1.7 m from the Ge array. The fully coded field-of-view is 16deg, the partially coded field of view amounts to 31deg, and the angular resolution is 2.5deg. The energy range extends from 20 keV to 8 MeV with a typical energy resolution of 2.5 keV at 1.3 MeV. Here we present the general concept of the instrument followed by a brief description of each of the main subsystems. INTEGRAL was successfully launched in October 2002 and SPI is functioning extremely well.

The addition of strain and p-doping in high-speed GaAs-based MQW lasers are assessed experimentally in terms of their potential for both increasing the differential gain, /spl part/g//spl part/N, and reducing the modulus of the differential refractive index, |/spl part/n//spl part/N|, in order to decrease the linewidth enhancement factor, /spl alpha/. The increased differential gain with strain alone is found to be offset by a corresponding increase of |/spl part/n//spl part/N|. The further addition of p-doping, on the other hand, simultaneously increases /spl part/g//spl part/N and decreases |/spl part/n//spl part/N|, yielding a substantial reduction in /spl alpha/. >

The density of a liquid can be determined from the acoustic parameters speed of sound and acoustic impedance. Unwanted deposits in pipelines and on sensor surfaces or gas bubbles in the fluid are common problems in industrial applications of ultrasonic sensors. Results of experiments and simulations of thin layer deposits show a correlation of the time delay of the reflected echo signal and the product of layer impedance and time of flight through the layer. This can be used for layer detection and error correction. The influence of gas bubbles on frequency and amplitude of the speed of sound sensor signal is shown. A correction of the speed of sound measurement error is presented, in which signal reconstruction and processing is used.

PKS 1622-297 was detected as a source of gamma-rays by the EGRET experiment at energies above 100 MeV during a gamma-ray outburst June and July 1995. We analyzed the COMPTEL data (0.75 - 30 MeV) of this time period to investigate the behaviour of PKS 1622-297 at lower gamma-ray energies. The blazar is significantly (5.7 sigma) detected by COMPTEL at energies above 10 MeV. Below 10 MeV the source is only marginally (3-10 MeV band) or not (below 3 MeV) detected. The summed MeV spectrum shows a 'hard' (alpha < 2, ~ E^(-alpha)) shape and, if combined with the simultaneous EGRET spectrum, a spectral break at MeV energies is indicated. We present the COMPTEL results (light curves, spectra) and compare them to results derived in neighbouring energy bands, in particular to the EGRET one., 4 pages including 5 figures, accepted for publication in the proceedings of the 4th INTEGRAL workshop, to appear in ESA-SP series

We present the time-averaged characteristics of the Crab pulsar in the 0.75-30 MeV energy window using data from the imaging Compton Telescope COMPTEL aboard the Compton Gamma-Ray Observatory (CGRO) collected over its 9 year mission. Exploiting the exceptionally long COMPTEL exposure on the Crab allowed us to derive significantly improved COMPTEL spectra for the Crab nebula and pulsar emissions, and for the first time to accurately determine at low-energy gamma-rays the pulse profile as a function of energy. These timing data, showing the well-known main pulse and second pulse at a phase separation of 0.4 with strong bridge emission, are studied together with data obtained at soft/hard X-ray energies from the ROSAT HRI, BeppoSAX LECS, MECS and PDS, at soft gamma-rays from CGRO BATSE and at high-energy gamma-rays from CGRO EGRET in order to obtain a coherent high-energy picture of the Crab pulsar from 0.1 keV up to 10 GeV., Comment: 17 pages, accepted for publication in A&A main journal

Ziel dieser Studie der Chirurgischen Arbeitsgemeinschaft Onkologie (CAO) der Deutschen Gesellschaft fur Chirurgie war die Erfassung eines aktuellen Status des chirurgisch-onkologischen Vorgehens bei malignen Weichteiltumoren des Erwachsenen. In 19 Monaten wurden die Daten von 292 Patienten aus 99 Kliniken prospektiv erfast. 39% wurden an Uni-Kliniken, 36% in Schwerpunkt- und 24% in Krankenhausern der Grundversorgung therapiert. An den Extremitaten konnte in 96% ein extremitatenerhaltender Eingriff durchgefuhrt werden. Die Haufigkeit einer RO-Resektion unterschied sich in den einzelnen Kliniken nicht signifikant, jedoch kamen lokal ausgedehntere Verfahren und additive Masnahmen an Uni-Kliniken haufiger vor. Die Indikation zur adjuvanten Strahlentherapie differierte. Trotz radikaler Kompartmentresektion kam die adjuvante Strahlentherapie in 39% zur Anwendung; hingegen wurde auf sie nach weiter Exzision von high-grade Tumoren in 45% verzichtet. Am Stamm erfolgten trotz geringerer Radikalitat adjuvante Therapien nicht haufiger.

We present a new algorithm, called Multiresolution Regularized Expectation Maximization (MREM), for the reconstruction of gamma-ray intensity maps from COMPTEL data. The algorithm is based on the iterative Richardson-Lucy scheme to which we added a wavelet thresholding step in order to eliminate image-noise in the reconstruction. The wavelet thresholding explicitly accounts for spatial correlations in the data, and adapts the angular resolution locally, depending on the significance of the signal in the data. We compare the performance of MREM to that of the maximum entropy and the Richardson-Lucy algorithms by means of Monte-Carlo simulations of COMPTEL 1.809 MeV gamma-ray line observations. The simulations demonstrate that the maximum entropy and Richardson-Lucy algorithms provide virtually identical reconstructions which are heavily disturbed by image noise. MREM largely suppresses this noise in the reconstructions, showing only the significant structures that are present in the data. Application of MREM to COMPTEL 1.8 MeV gamma-ray line data results in a 1.809 MeV sky map that is much smoother than the maximum entropy or Richardson-Lucy reconstructions presented previously. The essential features of this map are (1) an asymmetric galactic ridge emission reaching from l=45 deg to l=240 deg, (2) a bright localised emission feature in the Cygnus region around (l,b)=(80 deg,0 deg), (3) two emission spots at l=317 deg and l=332 deg situated in the galactic plane, and (4) an extended emission region around (l,b)=(160 deg, 0 deg). Comparison of the MREM map to the simulated reconstructions demonstrates that the 1.809 MeV emission is confined to the galactic plane., Comment: 13 pages, 7 figures, A&A, in press

Deconvolving COMPTEL gamma-ray data into images presents a major methodological challenge. We developed a new algorithm called Multiresolution Regularized Expectation Maximization (MREM), which explicitly accounts for spatial correlations in the image by using wavelets (Dixon et al. 1998). We demonstrate that MREM largely suppresses image noise in the reconstruction, showing only significant structures that are present in the data. Application to 1.8 MeV data results in a sky map that is much smoother than the maximum entropy reconstructions presented previously, but it shows the same characteristic emission features which have been established earlier., Comment: 4 pages, 1 figure, Proc. of the 3rd INTEGRAL workshop, Taormina

Nach ileoanaler Pouchanlage wegen Colitis ulcerosa kommt es in 15–30% (2–4) der Patienten postoperativ zur Entwicklung einer Pouchitis. Man unterscheidet die idiopathische und die senkundare Pouchitis. Die sekundare Pouchitis ist durch zumeist operativ technisch bedingte Kompilationen ausgelost, und streng von der idiopathischen Pouchitis zu trennen. Die auslosenden Faktoren der Pouchitis sind weitestgehend unbekannt. Jedoch wird ein enger pathogenetischer Zusammenhang mit der Colitis ulcerosa postuliert [3]. Als mogliche Ursachen der Pouchitis werden neben immunologischen Prozessen, bakterielle Fehlbesiedlung und eine magelhafte Blutversorgung des Ileum-Reservoirs diskutiert.

Burst spectra over a restricted energy range look like a power law plus some curvature. Such spectra can be well fit by most models or mechanisms, and hence reveal little of the underlying physics. With the launch of the Compton Gamma Ray Observatory, we can construct composite spectra from tens of keV to tens of GeV. This wide spectral range yields burst spectra that can sharply confront models. We have constructed wide-range composite spectra for several bursts, two of which are presented here: GRB910601 and GRB910814. The energy ranges are 28 keV to 10 MeV and 100 keV to 200 MeV. These spectra were constructed from spectra by BATSE, EGRET, COMPTEL, and OSSE. The spectral shape of GRB910601 shows a continuous turnover between 100 keV and 1 MeV, with peak νFν at 500 keV. The spectral shape of GRB910814 is dominated by a sharp and strong spectral break near 2 MeV. In addition to these two broad spectra, we have derived an ‘average’ spectral shape for 20 bright bursts from 40 keV to 1500 keV. This average spectra will be useful for studies of the red shifting of average spectra.Burst spectra over a restricted energy range look like a power law plus some curvature. Such spectra can be well fit by most models or mechanisms, and hence reveal little of the underlying physics. With the launch of the Compton Gamma Ray Observatory, we can construct composite spectra from tens of keV to tens of GeV. This wide spectral range yields burst spectra that can sharply confront models. We have constructed wide-range composite spectra for several bursts, two of which are presented here: GRB910601 and GRB910814. The energy ranges are 28 keV to 10 MeV and 100 keV to 200 MeV. These spectra were constructed from spectra by BATSE, EGRET, COMPTEL, and OSSE. The spectral shape of GRB910601 shows a continuous turnover between 100 keV and 1 MeV, with peak νFν at 500 keV. The spectral shape of GRB910814 is dominated by a sharp and strong spectral break near 2 MeV. In addition to these two broad spectra, we have derived an ‘average’ spectral shape for 20 bright bursts from 40 keV to 1500 keV. This average ...

A great deal of effort has been devoted to simplifying the monolithic integration, and enhancing the high-speed modulation characteristics, of GaAs-based SQW lasers. MBE-grown, vertically-compact, high-speed GaAs/AlGaAs separate-confinement double heterostructure (SCDH) devices have been developed. >

We have previously demonstrated that the combination of strain and p-doping leads to substantial performance enhancements in the high-speed modulation characteristics of GaAs-based MQW lasers. Here, we investigate for the first time, both theoretically and experimentally, the improvements in the linewidth enhancement factor, /spl alpha/, resulting from the simultaneous addition of strain and p-doping in GaAs-based MQW lasers. >

We investigate p-dopant incorporation and the influence of p-doping on the gain and damping behaviour in GaAs-based strained multiple quantum well lasers. By adding 5x10high18-2x10high19 cmhigh-3 beryllium doping to the active region of In0.35Ga0.65As/GaAs strained multiple quantum well lasers (4 QW's), we are able to demonstrate both very efficient high-speed modulation (20 GHz at a DC bias current of 50 mA) and the first semiconductor lasers to achieve a direct modulation bandwidth of 30 GHz under DC bias (heat-sink temperature is equal 25 degree C).

The intrinsic modulation response of semiconductor lasers is dependent on the differential gain, which determines the relaxation frequency for a given current density, and the damping factor, K, which limits the ultimate 3-dB bandwidth. We investigated the dependence of both parameters in GaAs/AlGaAs and pseudomorphic In/sub y/Ga/sub 1-y/As/GaAs multiple-quantum-well lasers on the threshold gain by measuring the relative intensity noise power spectra of lasers with different facet reflectivities and cavity lengths. >

Modelling and experimental results are presented, comparing the performance of vertically compact, high-speed GaAs and Ina j,GN As multiple-quantum-well lasers. Both devices' show superior performance, although the advantages of replacing the GaAs quantum wells with paeudomorphic InG&s quantum wells are clearly demonstrated.

This is a working paper of ISO/IEC JTC1/SC22/WG5 that was presented to the WG5 meeting at Lund (Sweden) in June 1991.