The case for microbicides: A global priority

The HIV/AIDS epidemic continues to spread, undermining development, reversing health gains, and exacerbating poverty. It will be some time before a vaccine is available and accessible, thus there is an urgent need to identify additional prevention options, in particular a method that women control, which could save millions of lives. This report from the Population Council and International Family Health presents the case for microbicides—products used vaginally to prevent infection from HIV and other STIs in women and their sexual partners—and discusses recent progress and developments, outstanding challenges, and the action required to ensure that products will be made available to those who most need them. The field faces a number of constraints, most notably inadequate funding and lack of industry participation. The report concludes that a strategic research and development approach is critical to achieving this fundamentally important goal

The International Monetary Fund\u27s Imperiled Priority

The role of the Official Sector institutions as lenders in crisis situations has evolved over time, and, particularly in the context of the current euro area debt crisis, into something akin to a lender of last resort. Institutions like the International Monetary Fund regularly provide distressed sovereigns with lending at affordable rates when private funding has dried up. To be able to provide this kind of emergency relief in a manner that does not result in large losses for their stakeholders, these Official Sector institutions often assert that their lending will have de facto priority over private lending. As a practical matter, since other creditors could not sue to interfere with the sovereign’s choices regarding whom to pay and in what order, de facto priority was all that was needed in the past for the system to function. All of this may have changed since October 2012 as a result of one case: NML Capital v. Republic of Argentina. This case has given private creditors, for the first time in history, a weapon with which they can go after payments made to any other creditor that has equal legal priority to them, potentially including any Official Sector institution without de jure priority. This leads to the question of whether Official Sector institutions’ half-century-old claim of de facto priority for their lending status can be said to have evolved, as a matter of customary international law, to a level of de jure priority

Non-blocking Priority Queue based on Skiplists with Relaxed Semantics

Priority queues are data structures that store information in an orderly fashion. They are of tremendous importance because they are an integral part of many applications, like Dijkstra’s shortest path algorithm, MST algorithms, priority schedulers, and so on. Since priority queues by nature have high contention on the delete_min operation, the design of an efficient priority queue should involve an intelligent choice of the data structure as well as relaxation bounds on the data structure. Lock-free data structures provide higher scalability as well as progress guarantee than a lock-based data structure. That is another factor to be considered in the priority queue design. We present a relaxed non-blocking priority queue based on skiplists. We address all the design issues mentioned above in our priority queue. Use of skiplists allows multiple threads to concurrently access different parts of the skiplist quickly, whereas relaxing the priority queue delete_min operation distributes contention over the skiplist instead of just at the front. Furthermore, a non-blocking implementation guarantees that the system will make progress even when some process fails. Our priority queue is internally composed of several priority queues, one for each thread and one shared priority queue common to all threads. Each thread selects the best value from its local priority queue and the shared priority queue and returns the value. In case a thread is unable to delete an item, it tries to spy items from other threads\u27 local priority queues. We experimentally and theoretically show the correctness of our data structure. We also compare the performance of our data structure with other variations like priority queues based on coarse-grained skiplists for both relaxed and non-relaxed semantics

Evaluation of European Social Fund Priority 1 and Priority 4: extending employment opportunities to adults and young people

This evaluation report forms part of a suite of research gathering evidence on the delivery of the European Social Fund (ESF). It aims to improve understanding of the processes, range and delivery of ESF Priority 1 and Priority 4 provision within the 2007-2013 England and Gibraltar ESF Operational Programme (OP). Priority 1 and Priority 4 seek to increase employment and tackle worklessness through a mix of employment and skills provision, intended to support people to enter jobs and in some instances progress within work. The research is based on ten in-depth case studies of the delivery of Priority 1 and 4 provision, involving a total of 182 interviews with stakeholders in ESF Co-Financing Organisations, Jobcentre Plus, and ESF delivery contractors. Fieldwork for the evaluation was undertaken between January and March 2011. The evaluation was part-funded by ESF technical assistance under the 2007-2013 England and Gibraltar ESF programme evaluation strategy

Fixed points for multi-class queues

Burke's theorem can be seen as a fixed-point result for an exponential single-server queue; when the arrival process is Poisson, the departure process has the same distribution as the arrival process. We consider extensions of this result to multi-type queues, in which different types of customer have different levels of priority. We work with a model of a queueing server which includes discrete-time and continuous-time M/M/1 queues as well as queues with exponential or geometric service batches occurring in discrete time or at points of a Poisson process. The fixed-point results are proved using interchangeability properties for queues in tandem, which have previously been established for one-type M/M/1 systems. Some of the fixed-point results have previously been derived as a consequence of the construction of stationary distributions for multi-type interacting particle systems, and we explain the links between the two frameworks. The fixed points have interesting "clustering" properties for lower-priority customers. An extreme case is an example of a Brownian queue, in which lower-priority work only occurs at a set of times of measure 0 (and corresponds to a local time process for the queue-length process of higher priority work).Comment: 25 page

The effective bandwidth problem revisited

The paper studies a single-server queueing system with autonomous service and $\ell$ priority classes. Arrival and departure processes are governed by marked point processes. There are $\ell$ buffers corresponding to priority classes, and upon arrival a unit of the $k$th priority class occupies a place in the $k$th buffer. Let $N^{(k)}$, $k=1,2,...,\ell$ denote the quota for the total $k$th buffer content. The values $N^{(k)}$ are assumed to be large, and queueing systems both with finite and infinite buffers are studied. In the case of a system with finite buffers, the values $N^{(k)}$ characterize buffer capacities. The paper discusses a circle of problems related to optimization of performance measures associated with overflowing the quota of buffer contents in particular buffers models. Our approach to this problem is new, and the presentation of our results is simple and clear for real applications.Comment: 29 pages, 11pt, Final version, that will be published as is in Stochastic Model