Sustainable valorisation of organic urban wastes : insights from African case studies

Understanding the problems and potentials of the organic waste stream is perhaps the single most important step that city authorities in Africa could take in moving towards sustainable, affordable, effective and efficient waste management. This publication presents four examples of recent attempts to manage organic waste sustainably in the African context. The participants in the ‘Nairobi organic urban waste’ project have structured this case exercise in order to use the case studies as object lessons, to harvest genuine insights into the feasibility of a variety of ways to successfully and sustainably valorise urban organic waste streams. Three contemporary case examples of compost production are presented. These include composting by a community-based organisation in the Kenyan private sector and by a public-private partnership in Malawi. In all three cases, the project and case study focus is on the relations between city waste and the agricultural supply chain. A fourth case study describes the technical and economic potential to produce and use biogas from urban organic waste

Experimental Comparisons of Derivative Free Optimization Algorithms

In this paper, the performances of the quasi-Newton BFGS algorithm, the NEWUOA derivative free optimizer, the Covariance Matrix Adaptation Evolution Strategy (CMA-ES), the Differential Evolution (DE) algorithm and Particle Swarm Optimizers (PSO) are compared experimentally on benchmark functions reflecting important challenges encountered in real-world optimization problems. Dependence of the performances in the conditioning of the problem and rotational invariance of the algorithms are in particular investigated.Comment: 8th International Symposium on Experimental Algorithms, Dortmund : Germany (2009

ORB5: a global electromagnetic gyrokinetic code using the PIC approach in toroidal geometry

This paper presents the current state of the global gyrokinetic code ORB5 as an update of the previous reference [Jolliet et al., Comp. Phys. Commun. 177 409 (2007)]. The ORB5 code solves the electromagnetic Vlasov-Maxwell system of equations using a PIC scheme and also includes collisions and strong flows. The code assumes multiple gyrokinetic ion species at all wavelengths for the polarization density and drift-kinetic electrons. Variants of the physical model can be selected for electrons such as assuming an adiabatic response or a ``hybrid'' model in which passing electrons are assumed adiabatic and trapped electrons are drift-kinetic. A Fourier filter as well as various control variates and noise reduction techniques enable simulations with good signal-to-noise ratios at a limited numerical cost. They are completed with different momentum and zonal flow-conserving heat sources allowing for temperature-gradient and flux-driven simulations. The code, which runs on both CPUs and GPUs, is well benchmarked against other similar codes and analytical predictions, and shows good scalability up to thousands of nodes

The High Radiosensitizing Efficiency of a Trace of Gadolinium-Based Nanoparticles in Tumors

International audienceWe recently developed the synthesis of ultrasmall gadolinium-based nanoparticles (GBN), (hydrodynamic diameter <5 nm) characterized by a safe behavior after intravenous injection (renal clearance, preferential accumulation in tumors). Owing to the presence of gadolinium ions, GBN can be used as contrast agents for magnetic resonance imaging (MRI) and as radiosensitizers. The attempt to determine the most opportune delay between the intravenous injection of GBN and the irradiation showed that a very low content of radiosensitizing nanoparticles in the tumor area is sufficient (0.1 μg/g of particles, i.e. 15 ppb of gadolinium) for an important increase of the therapeutic effect of irradiation. Such a promising and unexpected result is assigned to a suited distribution of GBN within the tumor, as revealed by the X-ray fluorescence (XRF) maps

AUGMENT : a phase III study of lenalidomide plus rituximab versus placebo plus rituximab in relapsed or refractory indolent lymphoma

PURPOSE Patients with indolent non-Hodgkin lymphoma typically respond well to first-line immunochemotherapy. At relapse, single-agent rituximab is commonly administered. Data suggest the immunomodulatory agent lenalidomide could increase the activity of rituximab. METHODS A phase III, multicenter, randomized trial of lenalidomide plus rituximab versus placebo plus rituximab was conducted in patients with relapsed and/or refractory follicular or marginal zone lymphoma. Patients received lenalidomide or placebo for 12 cycles plus rituximab once per week for 4 weeks in cycle 1 and day 1 of cycles 2 through 5. The primary end point was progression-free survival per independent radiology review. RESULTS A total of 358 patients were randomly assigned to lenalidomide plus rituximab (n = 178) or placebo plus rituximab (n = 180). Infections (63% v 49%), neutropenia (58% v 23%), and cutaneous reactions (32% v 12%) were more common with lenalidomide plus rituximab. Grade 3 or 4 neutropenia (50% v 13%) and leukopenia (7% v 2%) were higher with lenalidomide plus rituximab; no other grade 3 or 4 adverse event differed by 5% or more between groups. Progression-free survival was significantly improved for lenalidomide plus rituximab versus placebo plus rituximab, with a hazard ratio of 0.46 (95% CI, 0.34 to 0.62; P < .001) and median duration of 39.4 months (95% CI, 22.9 months to not reached) versus 14.1 months (95% CI, 11.4 to 16.7 months), respectively. CONCLUSION Lenalidomide improved efficacy of rituximab in patients with recurrent indolent lymphoma, with an acceptable safety profile

Some Problems in Probabilistic Tomography

Given probability distributions F1 , F2 , . . ., Fk on R and distinct directions θ1, . . ., θk, one may ask whether there is a probability measure μ on R2 such that the marginal of μ in direction θj is Fj, j = 1, . . ., k. For example for k = 3 we ask what the marginal of μ at 45° can be if the x and y marginals are each say standard normal? In probabilistic language, if X and Y are each standard normal with an arbitrary joint distribution, what can the distribution of X + Y or X - Y be? This type of question is familiar to probabilists and is also familiar (except perhaps in that μ is positive) to tomographers, but is difficult to answer in special cases. The set of distributions for Z = X - Y is a convex and compact set, C, which contains the single point mass Z ≡ 0 since X ≡ Y, standard normal, is possible. We show that Z can be 3-valued, Z=0, ±a for any a, each with positive probability, but Z cannot have any (genuine) two-point distribution. Using numerical linear programming we present convincing evidence that Z can be uniform on the interval [-ε, ε] for ε small and give estimates for the largest such ε. The set of all extreme points of C seems impossible to determine explicitly. We also consider the more basic question of finding the extreme measures on the unit square with uniform marginals on both coordinates, and show that not every such measure has a support which has only one point on each horizontal or vertical line, which seems surprising

How university’s activities support the development of students’ entrepreneurial abilities: case of Slovenia and Croatia

The paper reports how the offered university activities support the development of students’ entrepreneurship abilities. Data were collected from 306 students from Slovenian and 609 students from Croatian universities. The study reduces the gap between theoretical researches about the academic entrepreneurship education and individual empirical studies about the student’s estimation of the offered academic activities for development of their entrepreneurial abilities. The empirical research revealed differences in Slovenian and Croatian students’ perception about (a) needed academic activities and (b) significance of the offered university activities, for the development of their entrepreneurial abilities. Additionally, the results reveal that the impact of students’ gender and study level on their perception about the importance of the offered academic activities is not significant for most of the considered activities. The main practical implication is focused on further improvement of universities’ entrepreneurship education programs through selection and utilization of activities which can fill in the recognized gaps between the students’ needed and the offered academic activities for the development of students’ entrepreneurial abilities

Buffered memory: a hypothesis for the maintenance of functional, virus-specific CD8(+) T cells during cytomegalovirus infection.

Chronic infections have been a major topic of investigation in recent years, but the mechanisms that dictate whether or not a pathogen is successfully controlled are incompletely understood. Cytomegalovirus (CMV) is a herpesvirus that establishes a persistent infection in the majority of people in the world. Like other herpesviruses, CMV is well controlled by an effective immune response and induces little, if any, pathology in healthy individuals. However, controlling CMV requires continuous immune surveillance, and thus, CMV is a significant cause of morbidity and death in immune-compromised individuals. T cells in particular play an important role in controlling CMV and both CD4(+) and CD8(+) CMV-specific T cells are essential. These virus-specific T cells persist in exceptionally large numbers during the infection, traffic into peripheral tissues and remain functional, making CMV an attractive vaccine vector for driving CMV-like T cell responses against recombinant antigens of choice. However, the mechanisms by which these T cells persist and differentiate while remaining functional are still poorly understood, and we have no means to promote their development in immune-compromised patients at risk for CMV disease. In this review, I will briefly summarize our current knowledge of CMV-specific CD8(+) T cells and propose a mechanism that may explain their maintenance and preservation of function during chronic infection