Exponential dichotomy for noninvertible linear difference equations: block triangular systems

In this paper, block upper triangular systems of linear difference equations are considered, in which the coefficient matrices are not assumed invertible. The relationship between the exponential dichotomy properties of such a system and its associated block diagonal system is studied. The reason it is important to study triangular systems is that any system of linear difference equations is kinematically similar to an upper triangular system. In the bounded invertible case, it is known that for equations on the intervals J = Z(+) or Z(-), a block upper triangular system has an exponential dichotomy if and only if the associated block diagonal system has one. However, when J = Z, only the sufficiency holds. The sufficiency extends to the noninvertible case, provided the off-diagonal matrices are bounded. However, the necessity does not hold even when J = Z(+) or Z(-). Nevertheless, if certain conditions are added, then the necessity does hold and it is also shown that these conditions are needed since it turns out that if both the triangular and diagonal systems have dichotomies, then these extra conditions must hold

Coal dust alters β-naphthoflavone-induced aryl hydrocarbon receptor nuclear translocation in alveolar type II cells

<p>Abstract</p> <p>Background</p> <p>Many polycyclic aromatic hydrocarbons (PAHs) can cause DNA adducts and initiate carcinogenesis. Mixed exposures to coal dust (CD) and PAHs are common in occupational settings. In the CD and PAH-exposed lung, CD increases apoptosis and causes alveolar type II (AT-II) cell hyperplasia but reduces CYP1A1 induction. Inflammation, but not apoptosis, appears etiologically associated with reduced CYP1A1 induction in this mixed exposure model. Many AT-II cells in the CD-exposed lungs have no detectable CYP1A1 induction after PAH exposure. Although AT-II cells are a small subfraction of lung cells, they are believed to be a potential progenitor cell for some lung cancers. Because CYP1A1 is induced via ligand-mediated nuclear translocation of the aryl hydrocarbon receptor (AhR), we investigated the effect of CD on PAH-induced nuclear translocation of AhR in AT-II cells isolated from <it>in vivo</it>-exposed rats. Rats received CD or vehicle (saline) by intratracheal (IT) instillation. Three days before sacrifice, half of the rats in each group started daily intraperitoneal injections of the PAH, β-naphthoflavone (BNF).</p> <p>Results</p> <p>Fourteen days after IT CD exposure and 1 day after the last intraperitoneal BNF injection, AhR immunofluorescence indicated that proportional AhR nuclear expression and the percentage of cells with nuclear AhR were significantly increased in rats receiving IT saline and BNF injections compared to vehicle controls. However, in CD-exposed rats, BNF did not significantly alter the nuclear localization or cytosolic expression of AhR compared to rats receiving CD and oil.</p> <p>Conclusion</p> <p>Our findings suggest that during particle and PAH mixed exposures, CD alters the BNF-induced nuclear translocation of AhR in AT-II cells. This provides an explanation for the modification of CYP1A1 induction in these cells. Thus, this study suggests that mechanisms for reduced PAH-induced CYP1A1 activity in the CD exposed lung include not only the effects of inflammation on the lung as a whole, but also reduced PAH-associated nuclear translocation of AhR in an expanded population of AT-II cells.</p

Predicting future cancer burden in the United States by artificial neural networks

Aims: To capture the complex relationships between risk factors and cancer incidences in the US and predict future cancer burden. Materials &amp; methods: Two artificial neural network (ANN) algorithms were adopted: a multilayer feed-forward network (MLFFNN) and a nonlinear autoregressive network with eXogenous inputs (NARX). Data on the incidence of the four most common tumors (breast, colorectal, lung and prostate) from 1992 to 2016 (available from National Cancer Institute online datasets) were used for training and validation, and data until 2050 were predicted. Results: The rapid decreasing trend of prostate cancer incidence started in 2010 will continue until 2018–2019; it will then slow down and reach a plateau after 2050, with several differences among ethnicities. The incidence of breast cancer will reach a plateau in 2030, whereas colorectal cancer incidence will reach a minimum value of 35 per 100,000 in 2030. As for lung cancer, the incidence will decrease from 50 per 100,000 (2017) to 31 per 100,000 in 2030 and 26 per 100,000 in 2050. Conclusion: This up-to-date prediction of cancer burden in the US could be a crucial resource for planning and evaluation of cancer-control programs

Bollettino Sismico Italiano 2011

Questo lavoro illustra lo stato della Rete Sismica Nazionale Italiana (RSNI) e le principali caratteristiche della sismicità in Italia nell’anno 2011. In tale anno, tramite i dati raccolti dalla RSNI, sono stati localizzati 16499 eventi registrati da 359 stazioni appartenenti sia all’INGV, sia ad altre reti locali e regionali connesse in tempo reale al Centro Nazionale Terremoti (CNT) di Roma. La magnitudo minima di completezza del Bollettino Sismico Italiano (BSI) è ML 1.5. La magnitudo massima è stata registrata per un evento localizzato nella pianura padano veneta (ML 4.8). Nella sismicità italiana del 2011 sono state individuate 46 sequenze sismiche rilevanti; tra esse riveste particolare interesse la sequenza nel Montefeltro: iniziata a fine maggio e durata diversi mesi, essa comprende due eventi di magnitudo ML 4.0. La sequenza del Pollino, iniziata nel 2009 e proseguita a più riprese fino al 25 ottobre 2012 con un evento di magnitudo MW 5.2, presenta a inizio 2011 un aumento della sismicità che è culminato con l’evento maggiore di quell’anno (ML 3.6). L’analisi del BSI ha inoltre permesso di individuare una nuova area caratterizzata da eventi di origine antropica (esplosioni in cava) che si aggiunge alle 16 già rilevate negli anni precedenti. In questo lavoro vengono analizzati anche i segnali prodotti da frane di crollo, molto diffuse nel nostro paese lungo gli archi montani alpini e appenninici

Bollettino Sismico Italiano 2009

Questo lavoro illustra lo stato della Rete Sismica Nazionale Italiana e descrive la sismicità italiana nell’anno 2009. Vengono evidenziate le principali sequenze sismiche occorse durante l’anno, con particolare riguardo alla sequenza sismica dell’aquilano-reatino. Nel 2009 la Rete Sismica Nazionale dell’INGV ha registrato circa 26000 terremoti avvenuti sul territorio nazionale e nelle aree limitrofe, che sono stati analizzati e localizzati dal gruppo di analisti sismologi che si occupano della redazione del Bollettino Sismico Italiano (BSI). La magnitudo minima di completezza Mc del BSI 2009, ovvero la soglia di magnitudo minima media calcolata su tutto il territorio nazionale, è risultata pari a ML 1.6 (il dato del BSI 2008 si attestava sul valore di ML 2.1). Il numero di stazioni sismiche attive (Rete Nazionale e reti locali) nel corso del 2009 è stato di 305 (279 nel 2008). Viene fornita infine una stima del numero e della magnitudo di eventi di origine antropica (esplosioni) presenti nel BSI 2009. This paper describes the status of the Italian National Seismic Network and the Italian seismicity in year 2009. We outline the main seismic sequences that occurred during the year, with particular emphasis on the L’Aquila-Rieti seismic period. The INGV National Seismic Network recorded about 26000 earthquakes in Italy and neighboring areas during 2009, which were analyzed and localized by the seismology group of analysts involved in the publication of the Italian Seismic Bulletin (BSI). The minimum magnitude of completeness Mc of the BSI 2009 is ML 1.6 (ML 2.1 in the BSI 2008). The number of active seismic stations during 2009 was 305 (279 in 2008). We provide an estimate of the number and magnitude of anthropic events (quarry-blasts) included in the BSI 2009

Bollettino Sismico Italiano 2010

This paper describes the status of the Italian National Seismic Network and the main feautures of the Italian seismicity in 2010. In that year the network counted 313 velocimeters and 107 accelerometers. More than 14500 earthquakes were located in Italy and surrounding areas and seas, with an average minimum magnitude of completeness MC = 1.6. Most of that seismicity appears in cluster (a spatio-temporal concentration of seismic events): in 2010 more than 70% of the located Italian earthquakes belongs to about 430 cluster. We selected all the cluster with at least 20 events of any magnitudes, and all the cluster with at least 10 events and at least one event of magnitude 2.5 or greater, and cluster with at least two events and one of magnitude 3.5 or greater, ending up with a list of 48 significant cluster. The Italian Seismic Bulletin contains also seismic events originated by anthropic activities (quarry explosions). Through the analysis of the last 7 years of data from the bulletin, we pinpointed 16 areas with extended extractive activities. Nevertheless the presence of quarries in Italy is so widespread that our list can be considered by no means complete. Extraction areas frequently coincide with regions affected by high seismicity rate. Records due to explosion quakes can show distinguishing characteristics (compressive first onset and a low frequency secondary phase). However, these markers are not present in all the artificial events, and are not sufficient to exclude the totality of the explosions from the bulletin. Nowadays the BSI incorporates, together with true tectonic earthquakes, a significant portion of low magnitude events due to explosions, evaluated about 5% in 2010