Language and tool support for event refinement structures in Event-B

Event-B is a formal method for modelling and verifying the consistency of chains of model refinements. The event refinement structure (ERS) approach augments Event-B with a graphical notation which is capable of explicit representation of control flows and refinement relationships. In previous work, the ERS approach has been evaluated manually in the development of two large case studies, a multimedia protocol and a spacecraft sub-system. The evaluation results helped us to extend the ERS constructors, to develop a systematic definition of ERS, and to develop a tool supporting ERS. We propose the ERS language which systematically defines the semantics of the ERS graphical notation including the constructors. The ERS tool supports automatic construction of the Event-B models in terms of control flows and refinement relationships. In this paper we outline the systematic definition of ERS including the presentation of constructors, the tool that supports it and evaluate the contribution that ERS and its tool make. Also we present how the systematic definition of ERS and the corresponding tool can ensure a consistent encoding of the ERS diagrams in the Event-B models

Jesuit pray-ers

Some trepidation accompanies this account of prayer, for I have long held the Seminar on Jesuit Spirituality in high regard, perhaps too readily canonizing its members and their writings. We entered the Society at the same time, the Seminar and I; from the middle of my tertianship, the Seminar-like my fellow tertians in faith sharing-now asks an account of my prayer

Trichoplax, the simplest known animal, contains an estrogen-related receptor: Implications for the evolution of vertebrate and invertebrate estrogen receptors

Although, as their names imply, vertebrate and invertebrate estrogen receptors [ERs] and estrogen-related receptors [ERRs] are related transcription factors, their evolutionary relationships to each other are not fully understood. We searched recently sequenced genome of _Trichoplax_, the simplest known animal, and genomes from three lophotrochozoans: _Capitella_, a worm, _Helobdella robusta_, a leech, and _Lottia gigantea_, a snail, to elucidate the origins and evolution of ERs and ERRs. BLAST found an ERR in _Trichoplax_, but no ER. BLAST searches of the lophotrochozaons found ERRs in all three and invertebrate ERs in _Capitella_ and _Lottia_, but not in _Helobdella_. These database searches and a phylogenetic analyses indicate that invertebrate ERs arose in a protostome, and vertebrate ERs arose later in deuterostome

The impact of polarized extragalactic radio sources on the detection of CMB anisotropies in polarization

Recent polarimetric surveys of extragalactic radio sources (ERS) at frequencies \nu>1GHz are reviewed. By exploiting all the most relevant data on the polarized emission of ERS we study the frequency dependence of polarization properties of ERS between 1.4 and 86GHz. For flat-spectrum sources the median (mean) fractional polarization increases from 1.5% (2-2.5%) at 1.4GHz to 2.5-3% (3-3.5%) at \nu>10GHz. Steep-spectrum sources are typically more polarized, especially at high frequencies where Faraday depolarization is less relevant. As a general result, we do not find that the fractional polarization of ERS depends on the total flux density at high radio frequencies, i.e >20GHz. Moreover, in this frequency range, current data suggest a moderate increase of the fractional polarization of ERS with frequency. A formalism to estimate ERS number counts in polarization and the contribution of unresolved polarized ERS to angular power spectra at Cosmic Microwave Background (CMB) frequencies is also developed and discussed. As a first application, we present original predictions for the Planck satellite mission. Our current results show that only a dozen polarized ERS will be detected by the Planck Low Frequency Instrument (LFI), and a few tens by the High Frequency Instrument (HFI). As for CMB power spectra, ERS should not be a strong contaminant to the CMB E-mode polarization at frequencies \nu>70GHz. On the contrary, they can become a relevant constraint for the detection of the cosmological B--mode polarization if the tensor-to-scalar ratio is <0.01.Comment: 14 pages, 7 figures. Accepted for publication in Advances in Astronomy, Special Issue: "Astrophysical Foregrounds in Microwave Surveys", editor-in-chief C. Burigana, (www.hindawi.com

02-01 "Economic Analysis in Environmental Reviews of Trade Agreements: Assessing the North American Experience"

Beginning in the late 1990s, Canada and the United States began requiring "Environmental Reviews (ERs)" of all trade agreements to be negotiated by each government. This paper, commissioned by the North American Commission for Environmental Cooperation, outlines how ERs have evolved in North America, and evaluates the different methodological approaches that have been employed in ERs thus far. We show that the ERs conducted to date have an encouraging number of strengths that can be built upon. However, we also establish that the art of conducting ERs is still in its infancy. We identify four limitations with the methodological approaches that have been employed in the most recent ERs. Based on an analysis of these limitations, we propose four ways to improve how ERs are conducted in the future:

Motif analysis of amphioxus, lamprey and invertebrate estrogen receptors and amphioxus and human estrogen-related receptors: Towards a better understanding of estrogen receptor evolution

*Background.* The origins of steroid-dependent regulation of the vertebrate estrogen receptor (ER) are poorly understood. Genes with statistically significant sequence similarity to vertebrate ERs have been found in lamprey, a basal vertebrate, and amphioxus, a basal chordate. Motif analysis of these sequences provides an opportunity to investigate early events in the evolution of the ER.&#xd;&#xa;*Results.* We used artificial intelligence-based software to construct twelve motifs specific to the estrogen-binding domain of ER[alpha] and ER[beta] in land vertebrates and teleosts. We mapped these ER-specific motifs onto the sequences of lamprey, amphioxus, invertebrate and selected vertebrate ERs and amphioxus, Ciona and human estrogen-related receptor (ERR). We find that lamprey ER contains eleven motifs common to ERs in the training set. In contrast, amphioxus ER contains only six motifs. Various invertebrate ERs contain either six or seven motifs. Unexpectedly, human and amphioxus ERRs contain nine of the twelve motifs, despite extensive sequence divergence during the descent of chordate ERs and ERRs from a common ancestor. We mapped the twelve motifs onto a multiple alignment of human, lamprey and amphioxus ERs, which depicted residues in human ER[alpha] that are known to bind estradiol. There is excellent conservation of these key residues in lamprey ER and poor conservation in amphioxus ER. Out of seventeen residues on human ER[alpha] that bind estradiol, sixteen and six are identical in lamprey and amphioxus ER, respectively. A phylogenetic tree of ERs and ERRs reveals a long branch for amphioxus ER, which is in agreement with the low sequence and motif similarity between amphioxus ER and other ERs.&#xd;&#xa;*Conclusions.* There are significant differences between _B. floridae_ ER and vertebrate ERs in the steroid-binding domain as measured by motif analysis and percent of amino acids that are known to stabilize estradiol in human ER[alpha]. The absence in lamprey ER of motif 10, which maps to the C-terminus half of [alpha]-helix 9, may be important in recognition of novel estrogens, such as 15[alpha]-hydroxy-estradiol. &#xd;&#xa

Possible predicative role of electrical risk score on transcatheter aortic valve replacement outcomes in older patients. preliminary data

Background:Transcatheter aortic valve replacement (TAVR) is an effective procedure capable to change the natural history of the degenerative aortic valve stenosis. Despite the TAVR, the patients with advanced valve disease and severe myocardial damage (low flow, gradient and ejection fraction)show high mortality level. Aim of this study was toevaluate the predicative power of a noninvasive and inexpensive test obtained by means of a simple standard 12-leads electrocardiogram,known as the Electrical Risk Score (ERS). Methods: ERS was composed by seven simple ECG markers: heart rate (>75 bpm); QRS duration (>110 ms), left ventricular hypertrophy (Sokolow-Lyon criteria), delayed QRS transition zone (≥ V4), frontal QRS-T angle (>90°), long QTBazett (>450 ms for men and >460 in women) or JTBazett(330 ms for men and > 340 ms for women);long T peak to T end interval (Tp-e)( >89 ms). An ERS ≥ 4was considered high risk for all-cause or cardiovascular mortality.We calculated retrospectively the pre-procedure ERS in 40 TAVR patients after one year of follow-up. Results: In the follow up the all-cause and cardiovascular mortality were respectively 25% and 15%.None of survivors reported ERS ≥ 4,moreover, the ERS was the strongest predictor of all-cause (odd ratio 3.73, 95% CI: 1.44-9.66, p<0.05) or cardiovascular (odd ratio 3.95, 95% CI: 1.09-14.27, p<0.05) mortality.ROC curves showed that ERS had the widest significant sensitivity-specificity area under the curve (auc) predicting all-cause (auc: 0.855, p<0.05) or cardiovascular mortality (auc: 0.908, p<0.05). Conclusions:In this pivotal study, ERS resulted an useful tool to stratify the risk of mortality in one-year follow-up TAVR patients. Obviously, it is necessary to confirm these data in large prospective studies

Self-cancellation of ephemeral regions in the quiet Sun

With the observations from the Helioseismic and Magnetic Imager aboard the Solar Dynamics Observatory, we statistically investigate the ephemeral regions (ERs) in the quiet Sun. We find that there are two types of ERs: normal ERs (NERs) and self-cancelled ERs (SERs). Each NER emerges and grows with separation of its opposite polarity patches which will cancel or coalesce with other surrounding magnetic flux. Each SER also emerges and grows and its dipolar patches separate at first, but a part of magnetic flux of the SER will move together and cancel gradually, which is described with the term "self-cancellation" by us. We identify 2988 ERs among which there are 190 SERs, about 6.4% of the ERs. The mean value of self-cancellation fraction of SERs is 62.5%, and the total self-cancelled flux of SERs is 9.8% of the total ER flux. Our results also reveal that the higher the ER magnetic flux is, (i) the easier the performance of ER self-cancellation is, (ii) the smaller the self-cancellation fraction is, and (iii) the more the self-cancelled flux is. We think that the self-cancellation of SERs is caused by the submergence of magnetic loops connecting the dipolar patches, without magnetic energy release.Comment: 6 pages, 4 figures, accepted for publication in ApJ