Competition Policy and Public Procurement in Developing Countries

Measures to support Competition Policy and enhance the efficiency of Public Procurement can enhance the impact of regional integration agreements. The first part addresses Competition Policy - measures employed by government to ensure a fair competitive market environment. Competition policy aims to ensure that markets remain competitive (through anti-trust or anti-cartel enforcement) or become competitive (through liberalisation). For a variety of reasons, competition is often restricted in developing countries and there are benefits from establishing some level of competition policy. Although the literature does not provide a blueprint, it provides guidance on the most useful ways to incorporate Competition Policy in regional agreements. The second part addresses issues in opening up public procurement and outlines the main potential sources of welfare gains. Open and transparent procurement can bring gains in terms of price reduction, competition and reduced corruption. While developing countries recognize these benefits for domestic policy, they appear opposed to including procurement commitments in international agreements.Competition Policy, Public Procurement, Regional Integration

Temperature dependent absorption cross-sections of HNO3 and N2O5

Absorption cross-sections for HNO3 and N2O5 have been measured in the wavelength region 220-450 nm, using a dual beam diode array spectrometer with a spectral resolution of 0.3 nm. The results for both compounds are in good agreement with recommended values at room temperature. However, the cross-sections of both HNO3 and N2O5 show a marked reduction with decreasing temperature in the range 295-233 K. The calculated photolysis rate of HNO3 at the low temperatures and high solar zenith angles characteristic of the polar winter and spring is significantly lower than previously estimated

Diagnosing and mapping pulmonary emphysema on X-ray projection images

To assess whether grating-based X-ray dark-field imaging can increase the sensitivity of X-ray projection images in the diagnosis of pulmonary emphysema and allow for a more accurate assessment of emphysema distribution. Lungs from three mice with pulmonary emphysema and three healthy mice were imaged ex vivo using a laser-driven compact synchrotron X-ray source. Median signal intensities of transmission (T), dark-field (V) and a combined parameter (normalized scatter) were compared between emphysema and control group. To determine the diagnostic value of each parameter in differentiating between healthy and emphysematous lung tissue, a receiver-operating-characteristic (ROC) curve analysis was performed both on a per-pixel and a per-individual basis. Parametric maps of emphysema distribution were generated using transmission, dark-field and normalized scatter signal and correlated with histopathology. Transmission values relative to water were higher for emphysematous lungs than for control lungs (1.11 vs. 1.06, p<0.001). There was no difference in median dark-field signal intensities between both groups (0.66 vs. 0.66). Median normalized scatter was significantly lower in the emphysematous lungs compared to controls (4.9 vs. 10.8, p<0.001), and was the best parameter for differentiation of healthy vs. emphysematous lung tissue. In a per-pixel analysis, the area under the ROC curve (AUC) for the normalized scatter value was significantly higher than for transmission (0.86 vs. 0.78, p<0.001) and dark-field value (0.86 vs. 0.52, p<0.001) alone. Normalized scatter showed very high sensitivity for a wide range of specificity values (94% sensitivity at 75% specificity). Using the normalized scatter signal to display the regional distribution of emphysema provides color-coded parametric maps, which show the best correlation with histopathology. In a murine model, the complementary information provided by X-ray transmission and dark-field images adds incremental diagnostic value in detecting pulmonary emphysema and visualizing its regional distribution as compared to conventional X-ray projections

Experimental validation of image contrast correlation between ultra-small-angle X-ray scattering and grating-based dark-field imaging using a laser-driven compact X-ray source: Experimentelle Verifizierung des Zusammenhangs zwischen Röntgen-Kleinwinkelstreuung und gitter-basierter Röntgen-Dunkelfeldbildgebung unter Verwendung eines laser-getriebenen Kompaktsynchrotrons

X-ray phase and dark-field contrast have recently been the source of much attention in the field of X-ray imaging, as they both contribute new imaging signals based on physical principles that differ from conventional X-ray imaging. With a so-called Talbot grating interferometer, both phase-contrast and dark-field images are obtained simultaneously with the conventional attenuation-based X-ray image, providing three complementary image modalities that are intrinsically registered. Whereas the physical contrast mechanisms behind attenuation and phase contrast are well understood, a formalism to describe the dark-field signal is still in progress. In this article, we report on correlative experimental results obtained with a grating interferometer and with small-angle X-ray scattering. Furthermore, we use a proposed model to quantitatively describe the results, which could be of great importance for future clinical and biomedical applications of grating-based X-ray imagin

Self-organising human gonads generated by a Matrigel-based gradient system.

BACKGROUND: Advances in three-dimensional culture technologies have led to progression in systems used to model the gonadal microenvironment in vitro. Despite demonstrating basic functionality, tissue organisation is often limited. We have previously detailed a three-dimensional culture model termed the three-layer gradient system to generate rat testicular organoids in vitro. Here we extend the model to human first-trimester embryonic gonadal tissue. RESULTS: Testicular cell suspensions reorganised into testis-like organoids with distinct seminiferous-like cords situated within an interstitial environment after 7 days. In contrast, tissue reorganisation failed to occur when mesonephros, which promotes testicular development in vivo, was included in the tissue digest. Organoids generated from dissociated female gonad cell suspensions formed loosely organised cords after 7 days. In addition to displaying testis-specific architecture, testis-like organoids demonstrated evidence of somatic cell differentiation. Within the 3-LGS, we observed the onset of AMH expression in the cytoplasm of SOX9-positive Sertoli cells within reorganised testicular cords. Leydig cell differentiation and onset of steroidogenic capacity was also revealed in the 3-LGS through the expression of key steroidogenic enzymes StAR and CYP17A1 within the interstitial compartment. While the 3-LGS generates a somatic cell environment capable of supporting germ cell survival in ovarian organoids germ cell loss was observed in testicular organoids. CONCLUSION: The 3-LGS can be used to generate organised whole gonadal organoids within 7 days. The 3-LGS brings a new opportunity to explore gonadal organogenesis and contributes to the development of more complex in vitro models in the field of developmental and regenerative medicine

The C-Band All-Sky Survey: Instrument design, status, and first-look data

The C-Band All-Sky Survey (C-BASS) aims to produce sensitive, all-sky maps of diffuse Galactic emission at 5 GHz in total intensity and linear polarization. These maps will be used (with other surveys) to separate the several astrophysical components contributing to microwave emission, and in particular will allow an accurate map of synchrotron emission to be produced for the subtraction of foregrounds from measurements of the polarized Cosmic Microwave Background. We describe the design of the analog instrument, the optics of our 6.1 m dish at the Owens Valley Radio Observatory, the status of observations, and first-look data.Comment: 10 pages, 11 figures, published in Proceedings of SPIE MIllimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy V (2010), Vol. 7741, 77411I-1 - 77411I-1

Systeme zur automatisierten Bewertung von Programmen und das ProFormA-Aufgabenaustauschformat

Das im Rahmen des niedersächsischen Qualitätspakt Lehre Projektes eCompetence and Utilities for Learners and Teachers (eCult/eCult+)1 stattfindende Projekt ProFormA2 beschäftigt sich im Wesentlichen mit Systemen zur automatisierten Bewertung von Lösungen zu Programmieraufgaben, die im Rahmen der Programmierausbildung an Universitäten eingesetzt werden. Diese Systeme (Grader) können individuelles, automatisiert generiertes Feedback zu in digitaler Form eingereichten Lösungen zur Verfügung stellen, das sowohl Studierenden als auch Lehrenden zeitnah einen Überblick über Lernfortschritte und mögliche Lernhürden bietet. (DIPF/Orig.

Measurement and modelling of noise-power-distance curves of a fixed-wing UAV

This paper presents an investigation into the noise produced by an unmanned aerial vehicle (UAV). The platform used, `Spotter', is a fixed-wing, light UAV comprising a 4-meter wingspan. Spotter was originally designed to perform long-endurance, all-weather patrol missions in coastal and maritime environments. This vehicle has been continuously upgraded and is now used in a broader range of applications. Increasing demand by research and industrial partners, as well as the UK Civil Certification Authority (CAA) has led to a survey of the Spotter's in-flight noise footprint. The CAA Operating Safety Case of this platform is currently being updated and the major findings are presented in the paper. Preliminary results were obtained in flight tests performed at the Draycot Aerodrome over two expeditions in the summer of 2021, in the UK. A series of flyovers, takeoff and landing operations were measured. Flyovers were performed at constant altitude at series of power settings, incrementing from low to maximum power output. These measurements are then used to generate Noise-Power-Distance curves for the Spotter UAV. Static directivity characteristics of the dual propeller setup were also measured, with intent of feeding into future airport exposure studies