An alternative specification of generalized linear mixed models

Consider stratified data in which Y_i1,…,Y_ini denote real-valued response variables corresponding to the observations from stratum i, i=1,…,m and suppose that Y_ij follows an exponential family distribution with canonical parameter of the form θ_ij=x_ijβ+γ_i. In analyzing data of this type, the stratum-specific parameters are often modeled as random effects; a commonly-used approach is to assume that γ₁,…,γ_m are independent, identically distributed random variables.The purpose of this paper is to consider an alternative approach to defining the random effects, in which the stratum means of the response variable are assumed to be independent and identically distributed, with a distribution not depending on β. It will be shown that inferences about β based on this formulation of the generalized linear mixed model have many desirable properties. For instance, inferences regarding β are less sensitive to the choice of random effects distribution, are less subject to bias from omitted stratum-level covariates and are less affected by separate between- and within-cluster covariate effects.     

A covert attention P300-based brain-computer interface: Geospell

The Farwell and Donchin P300 speller interface is one of the most widely used brain-computer interface (BCI) paradigms for writing text. Recent studies have shown that the recognition accuracy of the P300 speller decreases significantly when eye movement is impaired. This report introduces the GeoSpell interface (Geometric Speller), which implements a stimulation framework for a P300-based BCI that has been optimised for operation in covert visual attention. We compared the Geospell with the P300 speller interface under overt attention conditions with regard to effectiveness, efficiency and user satisfaction. Ten healthy subjects participated in the study. The performance of the GeoSpell interface in covert attention was comparable with that of the P300 speller in overt attention. As expected, the effectiveness of the spelling decreased with the new interface in covert attention. The NASA task load index (TLX) for workload assessment did not differ significantly between the two modalities. PRACTITIONER SUMMARY: This study introduces and evaluates a gaze-independent, P300-based brain-computer interface, the efficacy and user satisfaction of which were comparable with those off the classical P300 speller. Despite a decrease in effectiveness due to the use of covert attention, the performance of the GeoSpell far exceeded the threshold of accuracy with regard to effective spelling.     

Energy-aware lazy scheduling algorithm for energy-harvesting sensor nodes

The main problem in dealing with energy-harvesting (EH) sensor nodes is represented by the scarcity and non-stationarity of powering, due to the nature of the renewable energy sources. In this work, the authors address the problem of task scheduling in processors located in sensor nodes powered by EH sources. Some interesting solutions have appeared in the literature in the recent past, as the lazy scheduling algorithm (LSA), which represents a performing mix of scheduling effectiveness and ease of implementation. With the aim of achieving a more efficient and conservative management of energy resources, a new improved LSA solution is here proposed. Indeed, the automatic ability of foreseeing at run-time the task energy starving (i.e. the impossibility of finalizing a task due to the lack of power) is integrated within the original LSA approach. Moreover, some modifications have been applied in order to reduce the LSA computational complexity and thus maximizing the amount of energy available for task execution. The resulting technique, namely energy-aware LSA, has then been tested in comparison with the original one, and a relevant performance improvement has been registered both in terms of number of executable tasks and in terms of required computational burden.     

The Cost of Irrigation Water Delivery: An Attempt to Reconcile the Concepts of Cost and Efficiency

This work discusses the conflict between two of the main objectives of the EU Water Framework Directive: cost recovery and economic efficiency in the use of irrigation water. In the Mediterranean region, this conflict is commonly embedded in a state of under-utilization of irrigation networks managed by Water User Associations (WUAs). This under-utilization arises from factors independent of farmers’ choice, such as water shortage, crises in the sector, and changes to the Common Agricultural Policy. This prevents the facilities from operating at the minimum average cost. This paper argues that farmers should not suffer this inefficiency, which results in them paying higher water prices to cover the costs of water supply. Indeed, the application of the Water Directive should be rethought, taking into account the specific problems related to irrigation in the Mediterranean region. Based on an econometric analysis of the costs of water distribution in a WUA in Sardinia (Italy), we propose a payment system based on two components. Primarily there is a fee related to the number of hectares under irrigation. In addition there is a fee that considers the intensity of irrigation: this component is to encourage farmers to save water. The results show that the proposed approach has some desirable effects, including higher rates of cost recovery and possibly a reduction in the use of groundwater. Finally, the proposed system is not overly expensive for the rest of the community, who must bear the costs of inefficiencies in the use of irrigation water that do not depend on choices of farmers.     

Oligomeric 1,4-phenyleneterephthalamide. Synthesis by interfacial polycondensation and structural properties

The synthesis of a fully aromatic oligoamide by low temperature interfacial polycondensation between terephthaloyl chloride and 1,4-phenylenediamine is reported. The reaction product was characterized with respect to its physical properties and chemical structure by infrared, X-rays, electron spectroscopy for chemical analysis (ESCA), and mass spectroscopic techniques. Elemental and thermal analysis, as well as viscosimetric and titrimetric methods were applied to evaluate the average molecular weight of the oligomer, whose chain length consists mainly of 3 to 4 monomeric units.     

Oesophageal tuberculosis mimicking secondary oesophageal involvement of mediastinal neoplasm

During the last decade the number of cases of abdominal tuberculosis diagnosed in Western countries has dramatically increased. There are many reasons, including the appearance of AIDS and the increased morbidity of people across the world due to the westward migration of many people coming from areas with a high incidence of tuberculosis. Oesophageal involvement is rare in tuberculosis, occurring mainly as an extension of the disease from the adjacent tuberculous lymph nodes. Fifty-eight cases of oesophageal tuberculosis have so far been reported. We describe a patient affected by oesophageal tuberculosis mimicking secondary oesophageal involvement of mediastinal malignancy.     

Choline esters and biogenic amines in the hypobranchial gland of 55 molluscan species of the neogastropod Muricoidea superfamily

As many as 55 neogastropod molluscs, all belonging to the Muricoidea superfamily, have been investigated for occurrence and contents, in their hypobranchial gland (HG), of choline esters and, subordinately, biogenic amines. Very high amounts of esters, strictly localized in the median area of the HG, were found in all dye-secreting molluscs. The choline esters were represented by murexine, dihydromurexine and senecioylcholine. A fourth ester, acryloylcholine, occurred in the HG of a single, non dye-secreting mollusc. All the compounds displayed potent neuromuscular blocking actions in all examined vertebrate and invertebrate species, as well as potent nicotinic actions. Muscarinic effects were either lacking or unimportant. In addition to choline esters the HG occasionally contained known and hitherto unknown biogenic amines: tyramine, octopamine, 5-hydroxytryptamine, histamine, urocanylhistamine and imidazole-propionylhistamine. The interest of extending the search of bioactive compounds to carnivorous, predatory molluscs other than those described in this paper and, more, extensively, to any molluscan species provided with 'venomous' glands or apparatuses, is emphasized.     

Effects of herbs on hydrolytic and oxidative degradation of olive oil in canned tomatoes

The effects of adding mixtures of herbs such as garlic, laurel, and marjoram on selected chemical indices of olive oil from canned dried tomatoes were studied for various storage periods of up to 1 yr. Conventional analytical indices measured included acidity, PV, and p-anisidine value. Flavored samples showed kinetic constant values that were significantly (P=0.001) higher than unflavored ones, whereas oligopolymer and oxidized TG and DG contents were similar to or slightly higher than in the unflavored samples compared with those with herbs. The addition of the mixture of herbs slowed polymerization reactions but did not inhibit TG oxidation. Discrepancies between the results obtained by conventional analyses and high-performance size-exclusion chromatography indicated that the former approaches were insufficient to determine oxidative degradation of oil as a result of interferences from compounds in the food matrix.