Update on HIV in Western Europe

HIV infection in Western Europe is mainly concentrated among men who have sex with men, heterosexuals who acquired HIV from sub-Saharan African countries, and in people who inject drugs. The rate of newly diagnosed cases of HIV has remained roughly stable since 2004 whereas the number of people living with HIV has slowly increased due to new infections and the success of antiretroviral therapy in prolonging life. An ageing population is gradually emerging that will require additional care. There are large differences across countries in HIV testing rates, proportions of people who present to care with low CD4+ cell counts, accessibility to treatment and care, and rates of retention once in care. Improved collection of HIV surveillance data will benefit countries and help to understand their epidemic better. However, social inequalities experienced by people with HIV still remain in some regions and urgently need to be addressed

Predicting Infiltration and Surface Runoff from Reconstructed Spoils and Soils

A laboratory system was fabricated to measure infiltration and runoff from spoil and soil profiles constructed in rectangular bins. Construction, calibration and operation of a rainfall simulator is discussed and instrumentation used to measure transient infiltration and transmittance of water through experimental profiles is described. Spoil and soil materials from surface mines in Eastern and Western Kentucky were transported to the laboratory and used in constructing experimental profiles in rectangular bins (0.91 x 1.83 x 1.07 m). An extensive series of infiltration experiments were conducted utilizing a rainfall simulator and soil moisture monitoring instrumentation. A dual probe gamma density gauge was used to measure moisture content and tensiometers were used to measure soil matric suction. Initial moisture content, bulk density and rainfall rate were varied and respective responses of infiltration characteristics determined. Extremely low infiltration rates in Western Kentucky spoil material was attributed to relatively high bulk densities and well-graded particle constituency. Conversely, extremely high infiltration rates were observed for Eastern Kentucky shale material even at very high bulk densities. The sandstone material, however, exhibited infiltration rates of the same order of magnitude as that of Western Kentucky spoil material. Soil water characteristic curves were developed using the Brooks-Corey and Gardner procedures, based upon desortpion tensiometer data. Unsaturated hydraulic conductivity values were determined using the plane of zero flux procedure and compared with predictions resulting from models described by Campbell, Burdine and Mualem for situations involving reconstructed soil and spoil materials. There was generally good agreement between the models and plane of zero flux results, and excellent agreement with Campbell\u27s predictions. The infiltration process was modeled with the SCS curve number method, a modified form of Holtan\u27s equation, the Green-Ampt model and Richard\u27s equation. SCS curve numbers were determined by fitting the method to the observed results. Richards\u27 equation gave very good estimates of the infiltration process through the spoil profiles, but was only slightly better than the Green-Ampt model. None .of the models worked well for the profiles where macropore flow occurred through a two layer topsoil over spoil system

A more representative chamber: representation and the House of Lords

Since 1997 there has been substantive reform of the House of Lords in an effort to make the chamber ‘more democratic and more representative’. Whilst the Labour government failed to press ahead with any of the proposed plans for further reform following the removal of the bulk of the hereditary peers in 1999, it remained committed to the notion that such reform must make the second chamber ‘more representative’. The coalition government's programme advocates a long-term aspiration for a House wholly or mainly elected on the basis of proportional representation, and a short-term approach based on additional appointments to ensure a balance of the parties. What is clear in all of these proposals for reform is a desire for the House of Lords to become more representative than it is at present. However, what is less clear is what is meant by ‘representative’ – who the House of Lords is supposed to represent, and what form representation will take. Moreover, in proposing to make the chamber more representative, either through appointment or election, little attention has been paid to how the current House of Lords provides representation. This article examines these questions in the context of Pitkin's classic conceptions of representation and peers' attitudes towards their own representative rol

Biogeography of Caladenia (Orchidaceae), with special reference to the South-west Australian Floristic Region

Caladenia contains 376 species and subspecies, of which almost all are endemic to temperate and southern semiarid Australia. Eleven species occur in New Zealand, 10 of which are endemic, and one species is widely distributed in eastern Australia and the western Pacific. Only three species occur in both south-western and south-eastern Australia. At subgeneric level, Drakonorchis is endemic to the South-west Australian Floristic Region (SWAFR), Stegostyla to eastern Australia and New Zealand, whereas three subgenera, Calonema, Phlebochilus and Elevatae occur on both sides of the Nullarbor Plain. Subgenus Caladenia is primarily eastern Australian but also extends to the western Pacific. The largest subgenera (Calonema and Phlebochilus) have radiated extensively, with Calonema exhibiting a greater concentration of species in more mesic parts of the SWAFR than Phlebochilus. Within the SWAFR, the major biogeographic division within Caladenia follows the 600-mm isohyet. Within rainfall zones, biogeographic districts for Caladenia correlate with a combination of underlying geology and surface soils. Areas of high endemism contain diverse edaphic environments. Climatic and edaphic requirements are likely to be key drivers of rarity in Caladenia, although these parameters may be acting in concert with mycorrhizal and pollinator specificity

200-Gb/s Polarization Multiplexed Doubly Differential QPSK Signal Transmission over 80-km SSMF Using Tandem SSB without Optical Amplification

We propose 200-Gb/s polarization multiplexed tandem SSB DDQPSK with intradyne detection for 80-km SSMF transmission. Without optical amplification, dispersion compensation or carrier recovery, the simulated receiver sensitivity for 80-km transmission was below -25.5 dBm (at 7% HDFEC threshold)

Amplifier-free 200-Gb/s tandem SSB doubly differential QPSK signal transmission over 80-km SSMF with simplified receiver-side DSP

We numerically demonstrate 80-km standard single-mode fiber transmission without optical amplification, dispersion compensation or carrier recovery using 200-Gb/s tandem single sideband modulated doubly differential QPSK. Simulation results show that doubly differential encoding enables practically constant system performance for frequency offsets within ± 2.3 GHz and allows a linewidth tolerance of 2.5 × 10−3 at 1-dB receiver sensitivity penalty. Employing 2.9-MHz linewidth lasers, the receiver sensitivity penalty at 7% HD-FEC threshold for 80-km transmission is less than 0.2 dB. By adding a 12-symbol decision feedback in the 2nd differential operation of doubly differential decoding, the receiver sensitivity is improved by 3.7 dB

The Slitmask Alignment Tool: robust, efficient, and astronomer-friendly software for aligning multi-object slitmasks

Multi-object spectroscopy via custom slitmasks is a key capability on three instruments at the W. M. Keck Observatory. Before observers can acquire spectra they must complete a complex procedure to align each slit with its corresponding science target. We developed the Slitmask Alignment Tool (SAT), to replace a complex, inefficient, and error-prone slitmask alignment process that often resulted in lost sky time for novice and experienced observers alike. The SAT accomplishes rapid initial mask alignment, prevents field misidentification, accurately predicts alignment box image locations, corrects for flexure-induced image displacement, verifies the instrument and exposure configuration, and accommodates both rectangular and trapezoidal alignment box shapes. The SAT is designed to lead observers through the alignment process and coordinate image acquisition with instrument and telescope moves to improve efficiencies. By simplifying the process to just a few mouse clicks, the SAT enables even novice observers to achieve robust, efficient, and accurate alignment of slitmasks on all three Keck instruments supporting multislit spectroscopy, saving substantial observing time

A Chart Semantics for the Pi-Calculus

We present a graphical semantics for the pi-calculus, that is easier to visualize and better suited to expressing causality and temporal properties than conventional relational semantics. A pi-chart is a finite directed acyclic graph recording a computation in the pi-calculus. Each node represents a process, and each edge either represents a computation step, or a message-passing interaction. Pi-charts enjoy a natural pictorial representation, akin to message sequence charts, in which vertical edges represent control flow and horizontal edges represent data flow based on message passing. A pi-chart represents a single computation starting from its top (the nodes with no ancestors) to its bottom (the nodes with no descendants). Unlike conventional reductions or transitions, the edges in a pi-chart induce ancestry and other causal relations on processes. We give both compositional and operational definitions of pi-charts, and illustrate the additional expressivity afforded by the chart semantics via a series of examples