A single weekly Kt/Vurea target for peritoneal dialysis patients does not provide an equal dialysis dose for all

Copyright © 2016 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.Dialysis adequacy is traditionally based on urea clearance, adjusted for total body volume (Kt/Vurea), and clinical guidelines recommend a Kt/Vurea target for peritoneal dialysis. We wished to determine whether adjusting dialysis dose by resting and total energy expenditure would alter the delivered dialysis dose. The resting and total energy expenditures were determined by equations based on doubly labeled isotopic water studies and adjusted Kturea for resting energy expenditure and total energy expenditure in 148 peritoneal dialysis patients (mean age, 60.6 years; 97 male [65.5%]; 54 diabetic [36.5%]). The mean resting energy expenditure was 1534 kcal/d, and the total energy expenditure was 1974 kcal/day. Using a weekly target Kt/V of 1.7, Kt was calculated using V measured by bioimpedance and the significantly associated (r = 0.67) Watson equation for total body water. Adjusting Kt for resting energy expenditure showed a reduced delivered dialysis dose (ml/kcal per day) for women versus men (5.5 vs. 6.2), age under versus over 65 years (5.6 vs. 6.4), weight 80 kg (5.8 vs. 6.1), low versus high comorbidity (5.9 vs. 6.2), all of which were significant. Adjusting for the total energy expenditure showed significantly reduced dosing for those employed versus not employed (4.3 vs. 4.8), a low versus high frailty score (4.5 vs. 5.0) and nondiabetic versus diabetic (4.6 vs. 4.9). Thus, the current paradigm for a single target Kt/Vurea for all peritoneal dialysis patients does not take into account energy expenditure and metabolic rate and may lead to lowered dialysis delivery for the younger, more active female patient.Peer reviewedFinal Accepted Versio

BALANCING NON-FUNCTIONAL REQUIREMENTS IN CLOUD-BASED SOFTWARE: AN APPROACH BASED ON SECURITY-AWARE DESIGN AND MULTI-OBJECTIVE SOFTWARE DYNAMIC MANAGEMENT

Beyond its functional requirements, architectural design, the quality of a software system is also defined by the degree to which it meets its non-functional requirements. The complexity of managing these non-functional requirements is exacerbated by the fact that they are potentially conflicting with one another. For cloud-based software, i.e., software whose service is delivered through a cloud infrastructure, other constraints related to the features of the hosting data center, such as cost, security and performance, have to be considered by system and software designers. For instance, the evaluation of requests to access sensitive resources results in performance overhead introduced by policy rules evaluation and message exchange between the different geographically distributed components of the authorization system. Duplicating policy rule evaluation engines traditionally solves such performance issues, however such a decision has an impact on security since it introduces additional potential private data leakage points. Taking into account all the aforementioned features is a key factor to enhance the perceived quality of service (QoS) of the cloud as a whole. Maximizing users and software developers satisfaction with cloud-based software is a challenging task since trade-off decisions have to be dynamically taken between these conflicting quality attributes to adapt to system requirements evolution. In this thesis, we tackle the challenges of building a decision support method to optimize software deployment in a cloud environment. Our proposed holistic method operates both at the level of 1) Platform as a service (PaaS) by handling software components deployment to achieve an efficient runtime optimization to satisfy cloud providers and customers objectives 2) Guest applications by making inroads into the design of applications to enable the design of secure systems that also meet flexibility, performance and cost requirements. To thoroughly investigate these challenges, we identify three main objectives that we address as follows: The first objective is to achieve a runtime optimization of cloud-based software deployment at the Platform as a service (PaaS) layer, by considering both cloud customers and providers constraints. To fulfill this objective, we leverage the [email protected] paradigm to build an abstraction layer to model a cloud infrastructure. In a second step, we model the software placement problem as a multi-objective optimization problem and we use multi-objective evolutionary algorithms (MOEAs) to identify a set of possible cloud optimal configurations that exhibit best trade-offs between conflicting objectives. The approach is validated through a case study that we defined with EBRC1, a cloud provider in Luxembourg, as a representative of a software component placement problem in heterogeneous distributed cloud nodes. The second objective is to ameliorate the convergence speed of MOEAs that we have used to achieve a run-time optimization of cloud-based software. To cope with elasticity requirements of cloud-based applications, we improve the way the search strategy operates by proposing a hyper-heuristic that operates on top of MOEAs. Our hyper-heuristic uses the history of mutation effect on fitness functions to select the most relevant mutation operators. Our evaluation shows that MOEAs in conjunction with our hyper-heuristic has a significant performance improvement in terms of resolution time over the original MOEAs. The third objective aims at optimizing cloud-based software trade-offs by exploring applications design as a complementary step to the optimization at the level of the cloud infrastructure, tackled in the first and second objectives. We aimed at achieving security trade-offs at the level of guest applications by revisiting current practices in software methods. We focus on access control as a main security concern and we opt for guest applications that manage resources regulated by access control policies specified in XACML2. This focus is mainly motivated by two key factors: 1) Access control is the pillar of computer security as it allows to protect sensitive resources in a given system from unauthorized accesses 2) XACML is the de facto standard language to specify access control policies and proposes an access control architectural model that supports several advanced access requirements such as interoperability and portability. To attain this objective, we advocate the design of applications based on XACML architectural model to achieve a trade-off between security and flexibility and we adopt a three-step approach: First, we identify a lack in the literature in XACML with obligation handling support. Obligations enable to specify user actions that have to be performed before/during/after the access to resources. We propose an extension of the XACML reference model and language to use the history of obligations states at the decision making time. In this step, we extend XACML access control architecture to support a wider range of usage control scenarios. Second, in order to avoid degrading performance while using a secure architecture based on XACML, we propose a refactoring technique applied on access control policies to enhance request evaluation time. Our approach, evaluated on three Java policy-based systems, enables to substantially reduce request evaluation time. Finally, to achieve a trade-off between a safe security policy evolution and regression testing costs, we develop a regression-test-selection approach for selecting test cases that reveal faults caused by policy changes. To sum up, in all aforementioned objectives, we pursue the goal of analysing and improving the current landscape in the development of cloud-based software. Our focus on security quality attributes is driven by its crucial role in widening the adoption of cloud computing. Our approach brings to light a security-aware design of guest applications that is based on XACML architecture. We provide useful guidelines, methods with underlying algorithms and tools for developers and cloud solution designers to enhance tomorrow’s cloud-based software design. Keywords: XACML-policy based systems, Cloud Computing, Trade-offs, Multi-Objective Optimizatio

Comparison of resting and total energy expenditure in peritoneal dialysis patients and body composition measured by dual-energy X-ray absorptiometry

Under basal resting conditions muscle metabolism is reduced, whereas metabolism increases with physical activity. We wished to determine whether there was an association between resting energy expenditure (REE) and total energy expenditure (TEE) in peritoneal dialysis (PD) patients and lean body mass (LBM). We determined REE and TEE by recently validated equations, using doubly labelled isotopic water, and LBM by dual-energy X-ray absorptiometry (DXA) scanning. We studied 87 patients, 50 male (57.4%), 25 diabetic (28.7%), mean age 60.3±17.6 years, with a median PD treatment of 11.4 (4.7-29.5) months. The mean weight was 70.1±17.7 kg with a REE of 1509±245 kcal/day and TEE 1947±378 kcal/day. REE was associated with body size (weight r=0.78 and body mass index (BMI) r=0.72) and body composition (LBM r=0.77, lean body mass index (LBMI) r=0.76, r=0.62), all P<0.001). For TEE, there was an association with weight r=0.58, BMI r=0.49 and body composition (LBM r=0.64, LBMI (r=0.54), all P<0.001). We compared LBMI measured by DXA and that estimated by the Boer equation using anthropomorphic measurements, which overestimated and underestimated LBM for smaller patients and heavier patients, respectively. Muscle metabolism is reduced at rest and increases with physical activity. Whereas previous reports based on REE did not show any association with LBM, we found an association between both REE and TEE, using a recently validated equation derived from dialysis patients, and LBM measured by DXA scanning. Estimation of muscle mass from anthropomorphic measurements systematically overestimated LBM for small patients and conversely underestimated for heavier patients

Directional changes of the geomagnetic field in West Africa: Insights from the metallurgical site of Korsimoro

This work shows the first archeomagnetic directions from Western Africa measured on 32 iron smelting kilns dated between 650 and 1800 AD. The archeological excavation of the vast metallurgical site of Korsimoro established the existence of four distinct iron-smelting techniques. The time-frame of each technique could be clearly determined with radiocarbon dating. Many of the kilns investigated in this study could also be dated individually with residual charcoals found in their inside. The results indicate that the inclination of the field changed gradually from shallow normal to shallow reversed during 800 to 1300 AD, and then went back to shallow normal around 1600–1700 AD. The declination was instead stable around 10°E between 800 and 1400 AD, thereafter it started changing towards North. This trend correlates well with available secular variation curves from the Balkan and from Spain, and indicates that the field variation in West Africa was similar to the one in Europe

Deconfinement and freezeout boundaries in equilibrium thermal models

In different approaches, the temperature-baryon density plane of QCD matter is studied for deconfinement and chemical freezeout boundaries. Results from various heavy-ion experiments are compared with the recent lattice simulations, the effective QCD-like Polyakov linear-sigma model, and the equilibrium thermal models. Along the entire freezeout boundary, there is an excellent agreement between the thermal model calculations and the experiments. Also, the thermal model calculations agree well with the estimations deduced from the Polyakov linear-sigma model (PLSM). At low baryonic density or high energies, both deconfinement and chemical freezeout boundaries are likely coincident and therefore the agreement with the lattice simulations becomes excellent as well, while at large baryonic density, the two boundaries become distinguishable forming a phase where hadrons and quark-gluon plasma likely coexist.Comment: 8 pages, 2 figures, accepted for publication in AHE

Schackoinella Spina, a new benthic foraminiferal species from cold-water coral ecosystems of the alboran sea and the gulf of Cádiz

Schackoinella spina n. sp. has been found in the eastern Alboran Sea at five different stations in water depths ranging from 258–330 m, as well as in one 532 m deep station in the Gulf of Cádiz, north-eastern Atlantic Ocean. Three stations have been sampled with a giant box core (BC) and two stations with a gravity core (GC) system. The sediments of the BCs and the GCs are characterized by cold-water coral (CWC) debris and a high abundance of biogenic components (e.g., bryozoans, echinoderms, bivalves, gastropods, serpulids, foraminifera). The surface samples from the BCs were treated with an ethanol-rose Bengal solution following standardized sampling protocol. In the BC samples the specimens of Schackoinella spina n. sp., were collected from the surface (0–1 cm). In particular, one BC sample (MD13-3456BC) contained six live (stained) specimens and an abundance of non-stained specimens (46 per 50 cm3 sediment). The new species was found at several sediment depth intervals corresponding to a Holocene age.The occurrence of this small (60–140 mm) species in the Alboran Sea and Gulf of Cádiz has likely been overlooked in this region. Although not straightforward, the presence of this species in association with cold-water coral fragments and its absence in fine-grained pelagic sediments may indicate a relationship with this ecosystem

Palaeoenvironmental analysis of the Miocene barnacle facies: case studies from Europe and South America

Acorn barnacles are sessile crustaceans common in shallow-water settings, both in modern oceans and in the Miocene geological record. Barnacle-rich facies occur from polar to equatorial latitudes, generally associated with shallow-water, high-energy, hard substrates. The aim of this work is to investigate this type of facies by analysing, from the palaeontological, sedimentological and petrographical points of view, early Miocene examples from Northern Italy, Southern France and South-western Peru. Our results are then compared with the existing information on both modern and fossil barnacle-rich deposits. The studied facies can be divided into two groups. The first one consists of very shallow, nearshore assemblages where barnacles are associated with an abundant hard-substrate biota (e.g., barnamol). The second one includes a barnacle-coralline algae association, here named “barnalgal” (= barnacle / red algal dominated), related to a deeper setting. The same pattern occurs in the distribution of both fossil and recent barnacle facies. The majority of them are related to very shallow, high-energy, hard-substrate, a setting that represents the environmental optimum for the development of barnacle facies, but exceptions do occur. These atypical facies can be identified through a complete analysis of both the skeletal assemblage and the barnacle association, showing that barnacle palaeontology can be a powerful tool for palaeoenvironmental reconstruction