All-sky search algorithms for monochromatic signals in bar gravitational wave detector data

In this paper we design and develop several filtering strategies for the analysis of data generated by a resonant bar gravitational wave (GW) antenna, with the goal of assessing the presence (or absence) therein of long-duration monochromatic GW signals, as well as the eventual amplitude and frequency of the signals, within the sensitivity band of the detector. Such signals are most likely generated in the fast rotation of slightly asymmetric spinning stars. We develop practical procedures, together with a study of their statistical properties, which will provide us with useful information on the performance of each technique. The selection of candidate events will then be established according to threshold-crossing probabilities, based on the Neyman-Pearson criterion. In particular, it will be shown that our approach, based on phase estimation, presents a better signal-to-noise ratio than does pure spectral analysis, the most common approach.

Disturbance of wildlife by outdoor winter recreation: allostatic stress response and altered activity-energy budgets

Anthropogenic disturbance of wildlife is of growing conservation concern, but we lack comprehensive approaches of its multiple negative effects. We investigated several effects of disturbance by winter outdoor sports on free-ranging alpine Black Grouse by simultaneously measuring their physiological and behavioral responses. We experimentally flushed radio-tagged Black Grouse from their snow burrows, once a day, during several successive days, and quantified their stress hormone levels (corticosterone metabolites in feces [FCM] collected from individual snow burrows). We also measured feeding time allocation (activity budgets reconstructed from radio-emitted signals) in response to anthropogenic disturbance. Finally, we estimated the related extra energy expenditure that may be incurred: based on activity budgets, energy expenditure was modeled from measures of metabolism obtained from captive birds subjected to different ambient temperatures. The pattern of FCM excretion indicated the existence of a funneling effect as predicted by the allostatic theory of stress: initial stress hormone concentrations showed a wide inter-individual variation, which decreased during experimental flushing. Individuals with low initial pre-flushing FCM values augmented their concentration, while individuals with high initial FCM values lowered it. Experimental disturbance resulted in an extension of feeding duration during the following evening foraging bout, confirming the prediction that Black Grouse must compensate for the extra energy expenditure elicited by human disturbance. Birds with low initial baseline FCM concentrations were those that spent more time foraging. These FCM excretion and foraging patterns suggest that birds with high initial FCM concentrations might have been experiencing a situation of allostatic overload. The energetic model provides quantitative estimates of extra energy expenditure. A longer exposure to ambient temperatures outside the shelter of snow burrows, following disturbance, could increase the daily energy expenditure by >10%, depending principally on ambient temperature and duration of exposure. This study confirms the predictions of allostatic theory and, to the best of our knowledge, constitutes the first demonstration of a funneling effect. It further establishes that winter recreation activities incur costly allostatic behavioral and energetic adjustments, which call for the creation of winter refuge areas together with the implementation of visitor-steering measures for sensitive wildlife.

Identification of neuronal network properties from the spectral analysis of calcium imaging signals in neuronal cultures

Neuronal networks in vitro are prominent systems to study the development of connections in living neuronal networks and the interplay between connectivity, activity and function. These cultured networks show a rich spontaneous activity that evolves concurrently with the connectivity of the underlying network. In this work we monitor the development of neuronal cultures, and record their activity using calcium fluorescence imaging. We use spectral analysis to characterize global dynamical and structural traits of the neuronal cultures. We first observe that the power spectrum can be used as a signature of the state of the network, for instance when inhibition is active or silent, as well as a measure of the network's connectivity strength. Second, the power spectrum identifies prominent developmental changes in the network such as GABAA switch. And third, the analysis of the spatial distribution of the spectral density, in experiments with a controlled disintegration of the network through CNQX, an AMPA-glutamate receptor antagonist in excitatory neurons, reveals the existence of communities of strongly connected, highly active neurons that display synchronous oscillations. Our work illustrates the interest of spectral analysis for the study of in vitro networks, and its potential use as a network-state indicator, for instance to compare healthy and diseased neuronal networks.

ICA Cleaning procedure for EEG signals analysis: application to Alzheimer's disease detection

To develop systems in order to detect Alzheimer’s disease we want to use EEG signals. Available database is raw, so the first step must be to clean signals properly. We propose a new way of ICA cleaning on a database recorded from patients with Alzheimer's disease (mildAD, early stage). Two researchers visually inspected all the signals (EEG channels), and each recording's least corrupted (artefact-clean) continuous 20 sec interval were chosen for the analysis. Each trial was then decomposed using ICA. Sources were ordered using a kurtosis measure, and the researchers cleared up to seven sources per trial corresponding to artefacts (eye movements, EMG corruption, EKG, etc), using three criteria: (i) Isolated source on the scalp (only a few electrodes contribute to the source), (ii) Abnormal wave shape (drifts, eye blinks, sharp waves, etc.), (iii) Source of abnormally high amplitude ( �100 �V). We then evaluated the outcome of this cleaning by means of the classification of patients using multilayer perceptron neural networks. Results are very satisfactory and performance is increased from 50.9% to 73.1% correctly classified data using ICA cleaning procedure.

Derivation of an observer model adapted to irregular signals based on convolution channels.

Anthropomorphic model observers are mathe- matical algorithms which are applied to images with the ultimate goal of predicting human signal detection and classification accuracy across varieties of backgrounds, image acquisitions and display conditions. A limitation of current channelized model observers is their inability to handle irregularly-shaped signals, which are common in clinical images, without a high number of directional channels. Here, we derive a new linear model observer based on convolution channels which we refer to as the "Filtered Channel observer" (FCO), as an extension of the channelized Hotelling observer (CHO) and the nonprewhitening with an eye filter (NPWE) observer. In analogy to the CHO, this linear model observer can take the form of a single template with an external noise term. To compare with human observers, we tested signals with irregular and asymmetrical shapes spanning the size of lesions down to those of microcalfications in 4-AFC breast tomosynthesis detection tasks, with three different contrasts for each case. Whereas humans uniformly outperformed conventional CHOs, the FCO observer outperformed humans for every signal with only one exception. Additive internal noise in the models allowed us to degrade model performance and match human performance. We could not match all the human performances with a model with a single internal noise component for all signal shape, size and contrast conditions. This suggests that either the internal noise might vary across signals or that the model cannot entirely capture the human detection strategy. However, the FCO model offers an efficient way to apprehend human observer performance for a non-symmetric signal.

Performance benchmarking and incentive regulation – considerations of directing signals for electricity distribution companies

After the restructuring process of the power supply industry, which for instance in Finland took place in the mid-1990s, free competition was introduced for the production and sale of electricity. Nevertheless, natural monopolies are found to be the most efficient form of production in the transmission and distribution of electricity, and therefore such companies remained franchised monopolies. To prevent the misuse of the monopoly position and to guarantee the rights of the customers, regulation of these monopoly companies is required. One of the main objectives of the restructuring process has been to increase the cost efficiency of the industry. Simultaneously, demands for the service quality are increasing. Therefore, many regulatory frameworks are being, or have been, reshaped so that companies are provided with stronger incentives for efficiency and quality improvements. Performance benchmarking has in many cases a central role in the practical implementation of such incentive schemes. Economic regulation with performance benchmarking attached to it provides companies with directing signals that tend to affect their investment and maintenance strategies. Since the asset lifetimes in the electricity distribution are typically many decades, investment decisions have far-reaching technical and economic effects. This doctoral thesis addresses the directing signals of incentive regulation and performance benchmarking in the field of electricity distribution. The theory of efficiency measurement and the most common regulation models are presented. The chief contributions of this work are (1) a new kind of analysis of the regulatory framework, so that the actual directing signals of the regulation and benchmarking for the electricity distribution companies are evaluated, (2) developing the methodology and a software tool for analysing the directing signals of the regulation and benchmarking in the electricity distribution sector, and (3) analysing the real-life regulatory frameworks by the developed methodology and further develop regulation model from the viewpoint of the directing signals. The results of this study have played a key role in the development of the Finnish regulatory model.

Hepatic circadian clock oscillators and nuclear receptors integrate microbiome-derived signals.

The liver is a key organ of metabolic homeostasis with functions that oscillate in response to food intake. Although liver and gut microbiome crosstalk has been reported, microbiome-mediated effects on peripheral circadian clocks and their output genes are less well known. Here, we report that germ-free (GF) mice display altered daily oscillation of clock gene expression with a concomitant change in the expression of clock output regulators. Mice exposed to microbes typically exhibit characterized activities of nuclear receptors, some of which (PPARα, LXRβ) regulate specific liver gene expression networks, but these activities are profoundly changed in GF mice. These alterations in microbiome-sensitive gene expression patterns are associated with daily alterations in lipid, glucose, and xenobiotic metabolism, protein turnover, and redox balance, as revealed by hepatic metabolome analyses. Moreover, at the systemic level, daily changes in the abundance of biomarkers such as HDL cholesterol, free fatty acids, FGF21, bilirubin, and lactate depend on the microbiome. Altogether, our results indicate that the microbiome is required for integration of liver clock oscillations that tune output activators and their effectors, thereby regulating metabolic gene expression for optimal liver function.

Hepatic circadian clock oscillators and nuclear receptors integrate microbiome-derived signals.

The liver is a key organ of metabolic homeostasis with functions that oscillate in response to food intake. Although liver and gut microbiome crosstalk has been reported, microbiome-mediated effects on peripheral circadian clocks and their output genes are less well known. Here, we report that germ-free (GF) mice display altered daily oscillation of clock gene expression with a concomitant change in the expression of clock output regulators. Mice exposed to microbes typically exhibit characterized activities of nuclear receptors, some of which (PPARα, LXRβ) regulate specific liver gene expression networks, but these activities are profoundly changed in GF mice. These alterations in microbiome-sensitive gene expression patterns are associated with daily alterations in lipid, glucose, and xenobiotic metabolism, protein turnover, and redox balance, as revealed by hepatic metabolome analyses. Moreover, at the systemic level, daily changes in the abundance of biomarkers such as HDL cholesterol, free fatty acids, FGF21, bilirubin, and lactate depend on the microbiome. Altogether, our results indicate that the microbiome is required for integration of liver clock oscillations that tune output activators and their effectors, thereby regulating metabolic gene expression for optimal liver function.

Some Notes and Comments on the Efficient use of Information in Repeated Games with Poisson Signals

In the present paper we characterize the optimal use of Poisson signals to establish incentives in the "bad" and "good" news models of Abreu et al. [1]. In the former, for small time intervals the signals' quality is high and we observe a "selective" use of information; otherwise there is a "mass" use. In the latter, for small time intervals the signals' quality is low and we observe a "fine" use of information; otherwise there is a "non-selective" use. JEL: C73, D82, D86. KEYWORDS: Repeated Games, Frequent Monitoring, Public Monitoring, Infor- mation Characteristics.

Heartworm (Dirofilaria immitis) disease in a Brazilian oncilla (Leopardus tigrinus)

Heartworm disease is caused by the intravascular nematode Dirofilaria immitis, a pathogen of public health importance usually associated to domestic dogs and cats, and to a lesser extend to other mammal species. The oncilla (Leopardus tigrinus) is a threatened neotropic felid species that naturally occurs in Brazil. Here, we report the encounter of adult and larval stages of heartworms in a female specimen of L. tigrinus, probable of free-ranging origin, from Ubatuba, São Paulo, Brazil, which died showing clinical signals compatible with heartworm disease. This was the first reported case of D. immitis infection and associated disease in L. tigrinus, also suggesting that the oncilla acted as a definitive host for this parasite. The present findings confirmed D. immitis as a pathogenic agent for this felid species, thus supporting the recommendation for the inclusion of diagnostic testing for this pathogen in routine health screening procedures for captive and free-ranging oncillas in Brazil, especially in those localities where climate conditions support the occurrence of the parasite. Potential reservoirs as oncillas are established beyond the reach of veterinary care, thus representing a continuing risk for domestic animals and humans acquiring heartworm infection. We encourage further serologic and molecular studies aiming to establish D. immitis prevalences in L. tigrinus and other wild carnivores in the region of Ubatuba, as well as ecological and veterinary studies to access the role of this pathogen for the survival of this threatened felid species.

Anti-Rickettsia spp. antibodies in free-ranging and captive capybaras from southern Brazil

Capybaras (Hydrochaeris hydrochaeris) are among the main hosts of Amblyomma spp. ticks, which is able to transmit Rickettsia species to human beings and animals. Since they are often infested with potential vector ticks, capybaras may be used as sentinels for rickettsiosis, such as the Brazilian Spotted Fever. The aim of the present study was to determine the prevalence of antibodies against Rickettsia spp. using the indirect immunofluorescence assay (IFA) in 21 free-ranging and 10 captive animals from the Zoological Park of the 'Bela Vista Biological Sanctuary' (BVBS), Itaipu Binational, Foz do Iguaçu, Southern Brazil. Antigens of six rickettsial species already identified in Brazil (Rickettsia rickettsii, R. parkeri, R. bellii, R. rhipicephali, R. amblyommii and R. felis) were used for IFA. Ticks from each capybara were collected for posterior taxonomic identification. A total of 19 (61.3%) samples reacted to at least one of tested species. Seropositivity was found in 14 (45.2%), 12 (38.7%), 5 (16.1%), 4 (12.9%), 3 (9.7%) and 3 (9.7%) animals for R. rickettsii, R. bellii, R. parkeri, R. amblyommii, R. felis and R. rhipicephali, respectively. Two captive capybaras presented suggestive titers of R. rickettsii infection and one sample showed homologous reaction to R. parkeri. Only one free-ranging capybara presented evidence R. bellii infection. Ticks collected on capybaras were identified as Amblyomma dubitatum e Amblyomma sp. Results evidenced the rickettsial circulation in the area, suggesting a potential role of capybaras on bacterial life cycle.