Long-pulse KrCl laser with a high discharge quality \ud

The discharge quality and optimum pump parameters of a long-pulse high-pressure gas discharge excited KrCl laser are investigated. A three-electrode prepulse–mainpulse excitation circuit is employed as pump source. The discharge volume contains a gas mixture of HCl/Kr/Ne operated at a total pressure of up to 5 bar. For a plane–plane resonator, the divergence of both output laser beams is measured. A low beam divergence of less than 1 mrad is measured as a result of the very high discharge homogeneity. A maximum laser pulse duration of 150 ns (FWHM) is achieved for a pump duration of 270 ns (FWHM) and a power density of 340 kW cm-3. Pumping the discharge under optimum conditions employing a stable resonator results in a maximum specific energy of 0.45 J/l with a laser pulse duration of 117 ns and an efficiency of 0.63% based on the deposited energy

Molecular Imaging of Cardiovascular Disease

The ability to visualize morphology and function of the heart plays a central role in cardiology practice today. However, clinical tools to diagnose processes in an early phase on a molecular level in order to prevent dysmorphy or dysfunction are still lacking. There is a need for early diagnosis of molecular processes on a pre-disease level and the ability to monitor existing and novel treatments enabling personalized medicine. Molecular imaging is emerging in research and early clinical trials as a very promising approach in diagnosis and monitoring of heart disease. In this review we aim to discuss the potential of molecular imaging in cardiovascular disease

Realizability toposes and ordered PCA's

Partial combinatory algebras (pca's, for short), are well-known to form the basic ingredient for the construction of various realizability toposes, of which the Eective Topos is undoubtedly the most famous. There is more than one way to present the realizability topos associated to a pca; one may take the exact completion of the category of partitioned assemblies (see [7]), or one can use tripos theory. Triposes built from pca's are, together with those from locales, the most important and most extensively studied instances of triposes, but from a structural point of view, there are important dierences between the two; whereas locales are organized in a well-behaved category, which is a re ective subcategory of the category of toposes, it is not immediately clear what an appropriate category for pca's may look like. Moreover, there are various nice properties in the localic case, such as the fact that there is a one-to-one correspondence between maps of locales and geometric morphisms between the corresponding sheaf toposes, and also the fact that this correspondence preserves epi-mono factorizations; such anintimate connection is absent for pca's

Polymorphic Automorphisms and the Picard Group

We investigate the concept of definable, or inner, automorphism in the logical setting of partial Horn theories. The central technical result extends a syntactical characterization of the group of such automorphisms (called the covariant isotropy group) associated with an algebraic theory to the wider class of quasi-equational theories. We apply this characterization to prove that the isotropy group of a strict monoidal category is precisely its Picard group of invertible objects. Furthermore, we obtain an explicit description of the covariant isotropy group of a presheaf category

Giant scour-fills in ancient channel-lobe transition zones: Formative processes and depositional architecture

Scours are common features of modern deep-marine seascapes, particularly downstream of the mouths of slope channels within channel-lobe transition zones (CLTZs). Their dimensions can exceed hundreds of metres in width and length, and tens of metres in depth. However, the stratigraphic architecture of the infill of these erosional bedforms is rarely described from the rock record and no large (>100 m width) scours have been described in detail from exhumed CLTZs. Here, the infill of two erosional features (0.5-1 km long and 15-20 m thick) from the Permian Karoo Basin succession, South Africa, are presented from palaeogeographically well- constrained CLTZs; one from Fan 3 in the Tanqua depocentre and one from Unit A5 in the Laingsburg depocentre. The basal erosion surfaces of the features are asymmetric with steep, undulating, and composite upstream margins, and low gradient simple downstream margins. The basal infill consists of thin-bedded siltstone and sandstone beds cut by closely-spaced scours; these beds are interpreted as partially reworked fine grained tails of bypassing flows with evidence for flow deflection. The erosional features are interpreted as giant scour-fills. The internal architecture suggests different evolutionary histories for each case. The Unit A5 scour-fill shows a simple cut-and-fill history with lateral and upward transitions from siltstone- to sandstone-prone deposits. In contrast, the Fan 3 scour-fill shows headward erosion and lengthening of the scour surface suggesting temporal changes in the interaction between turbidity currents and the scour surface. This relationship could support the occurrence of a hydraulic jump during part of the fill history, while the majority of the fill represents deposition from subcritical flows. Diversity in scour preservation mechanisms could explain the variety in depositional histories. The architecture, sedimentary facies and palaeoflow patterns of the scour-fills are distinctly different to well documented adjacent basin-floor channel-fills at the same stratigraphic levels. The recognition of scour-fills helps to constrain their sedimentological and stratigraphic expression in the subsurface, and to improve our understanding of the stratigraphic architecture of channel-lobe transition zones

Implementaion of a combined OFDM-demodulation and WCDMA-equalization module

For a dual-mode baseband receiver for the OFDMWireless LAN andWCDMA standards, integration of the demodulation and equalization tasks on a dedicated hardware module has been investigated. For OFDM demodulation, an FFT algorithm based on cascaded twiddle factor decomposition has been selected. This type of algorithm combines high spatial and tempo- ral regularity in the FFT data-flow graphs with a minimal number of computations. A frequency-domain algorithm based on a circulant channel approximation has been se- lected forWCDMA equalization. It has good performance, low hardware complexity and a low number of computa- tions. Its main advantage is the reuse of the FFT kernel, which contributes to the integration of both tasks. The demodulation and equalization module has been de- scribed at the register transfer level with the in-house developed Arx language. The core of the module is a pipelined radix-23 butterfly combined with a complex mul- tiplier and complex divider. The module has an area of 0.447 mm2 in 0.18 μm technology and a power consump- tion of 10.6 mW. The proposed module compares favorably with solutions reported in literature. Keywords—OFDMdemodulation,WCDMA, frequency- domain equalization, architecture design

Pathways of self-reported problem behaviors from adolescence into adulthood

OBJECTIVE: The authors determined the impact of different pathways of psychopathological development on adult outcome in subjects followed from ages 11-18 to ages 21-28. METHOD: Problem behaviors of subjects from a general population sample were assessed through the Youth Self-Report and the Young Adult Self-Report given at four time points (1987, 1989, 1991, and 1997). In addition, DSM-IV diagnoses, information pertaining to signs of maladjustment, and measures of social functioning were obtained at the last assessment. On the basis of the self-report ratings, four contrasting developmental pathways of psychopathology were determined: persistent, decreasing, increasing, and consistently normal. RESULTS: Subjects whose overall level of psychopathology was persistent over time had a higher lifetime prevalence of DSM-IV diagnoses and a poorer general outcome in adulthood than did subjects whose level of psychopathology increased. Subjects whose level of psychopathology returned to normal after high levels of problems in adolescence were only slightly different in terms of outcome from subjects with consistently normal ratings. CONCLUSIONS: 1) People who showed high levels of problems in early adolescence but whose level of psychopathology diminished by adulthood seemed to be as healthy as people who never attained a serious level of psychopathology. 2) An ongoing devious pathway into adulthood had negative effects on many domains of functioning. These two findings are both powerful arguments for early intervention in adolescence