On the computation of the term w21z2zˉw_{21}z^2\bar{z} of the series defining the center manifold for a scalar delay differential equation

In computing the third order terms of the series of powers of the center manifold at an equilibrium point of a scalar delay differential equation, with a single constant delay $r>0,$ some problems occur at the term $w_{21}z^2\bar{z}.$ More precisely, in order to determine the values at 0, respectively $-r$ of the function $w_{21}(\,.\,),$ an algebraic system of equations must be solved. We show that the two equations are dependent, hence the system has an infinity of solutions. Then we show how we can overcome this lack of uniqueness and provide a formula for $w_{21}(0).$Comment: Presented at the Conference on Applied and Industrial Mathematics- CAIM 2011, Iasi, Romania, 22-25 September, 2011. Preprin

The Spatial Clustering of Low Luminosity AGN

We present the first multi-parameter analysis of the narrow line AGN clustering properties. Estimates of the two-point correlation function (CF) based on SDSS DR2 data reveal that Seyferts are clearly less clustered than normal galaxies, while the clustering amplitude (r_0) of LINERs is consistent with that of the parent galaxy population. The similarities in the host properties (color and concentration index) of Seyferts and LINERs suggest that the difference in their r_0 is not driven by the morphology-density relation. We find that the luminosity of [O I] emission shows the strongest influence on AGN clustering, with low L([O I]) sources having the highest r_0. This trend is much stronger than the previously detected dependence on L([O III]), which we confirm. There is a strong correspondence between the clustering patterns of objects of given spectral type and their physical properties. LINERs, which exhibit high r_0, show the lowest luminosities and obscuration levels, and relatively low gas densities (n_e), suggesting that these objects harbor black holes that are relatively massive yet weakly active or inefficient in their accretion, probably due to the insufficiency of their fuel supply. Seyferts, which have low r_0, are luminous and show large n_e, suggesting that their black holes are less massive but accrete quickly and efficiently enough to clearly dominate the ionization. The low r_0 of the H II galaxies can be understood as a consequence of both the morphology-density and star formation rate-density relations, however, their spectral properties suggest that their centers hide amidst large amounts of obscuring material black holes of generally low mass whose activity remains relatively feeble. Our own Milky Way may be a typical such case.[abridged]Comment: 27 pages, color figures, some are severely degraded in resolution, emulateapj. See http://www.physics.drexel.edu/~constant/work/agnclustering.ps for high resolution version. Accepted to Ap

Structural brain complexity and cognitive decline in late life : A longitudinal study in the Aberdeen 1936 Birth Cohort

Copyright © 2014 Elsevier Inc. All rights reserved.Peer reviewedPostprin

Active Galactic Nuclei in Void Regions

We present a comprehensive study of accretion activity in the most underdense environments in the universe, the voids, based on the SDSS DR2 data. Based on investigations of multiple void regions, we show that AGN's occurrence rate and properties differ from those in walls. AGN are more common in voids than in walls, but only among moderately luminous and massive galaxies (M_r < -20, log M_*/M_sun < 10.5), and this enhancement is more pronounced for the weakly accreting systems (i.e., L_[O III] < 10^39 erg/s). Void AGN hosted by moderately massive and luminous galaxies are accreting at equal or lower rates than their wall counterparts, show less obscuration than in walls, and similarly aged stellar populations. The very few void AGN in massive bright hosts accrete more strongly, are more obscured, and are associated with younger stellar emission than wall AGN. Thus, accretion strength is probably connected to the availability of fuel supply, and accretion and star-formation co-evolve and rely on the same source of fuel. Nearest neighbor statistics indicate that the weak accretion activity (LINER-like) is not influenced by the local environment. However, H IIs, Seyferts, and Transition objects prefer more grouped small scale structures, indicating that the rate at which galaxies interact with each other affects their activity. These trends support a potential H II -> Seyfert/Transition Object -> LINER evolutionary sequence that we show is apparent in many properties of actively line-emitting galaxies, in both voids and walls. The subtle differences between void and wall AGN might be explained by a longer, less disturbed duty cycle of these systems in voids.Comment: 19 pages, 7 figures (1 color); to appear in ApJ, submitted on May 11, 200

The transpleurodiaphragmatic laparoscopic approach of liver hydatid cysts of VII TH segment

Clinica Chirurgie II, Spitalul Clnic de Urgență, Sibiu, Spitalul Militar de Urgență, Sibiu, Departamentul de Imagistică Medicală, Spitalul Clnic de Urgență, Sibiu, Clinica ATI I, Spitalul Clnic de Urgență, Sibiu, Al XI-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” din Republica Moldova și cea de-a XXXIII-a Reuniune a Chirurgilor din Moldova „Iacomi-Răzeșu” 27-30 septembrie 2011Localizarile chistelor hepatice, cu precadere a chistelor hidatice hepatice în sectorul posterior, respectiv, segmentul VII, dificil de abordat în chirurgia „conventionaăa” deschisă sau laparoscopică, care frecvent necesită sacrificii parietale semnificative, uneori adevarate „demolări”, poate beneficia de un abord laparoscopic atipic, securizat, cu rezultate bune atât pentru pacient cât și pentru chirurg, cu un impact minimal, ce favorizeaza o vindecare repidă și o reintegrare socioprofesională precoce. Abordul transpleurodiafragmatic utilizand „Dispozitivul pentru aspirația chistului hidatic hepatic sau al chistului de ovar” (OSIM Brevet 120809/30.04.2008, Inventator – Dan Sabau) în asociere cu dispozitivul de fragmentare a continutului chistic, cu performanțe deosebite (OSIM Brevet no. 120810/30.04.2008, INventator - Dan Sabau) este cea mai adecvată metodă de soluționare a problemelor generate de această localizare posterioară, care devine astfel accesibilă pentru chirurgi, chiar și cu o minimă experiență în chirurgia laparoscopică sau toracoscopică. Numarul relatic redus de cazuri (3), nu permite decât formularea unor concluzii preliminare asupra metodei, care rămâne să fie validată de rezultate ulterioare.The localizations of liver cysts, and particularly of hydatid cysts, in the posterior hepatic dome (segment VII), difficult to approach in “conventional” open or laparoscopic surgery, with significant parietal sacrifices and “demolition”, require a secure atypical laparoscopic approach, with positive results for both patient and surgeon, with minimal impact, with social and professional reintegration and faster healing. Transpleurodiaphragmatic laparoscopic approach using the “Device for aspiration of liver hydatid cyst or ovarian cyst” (OSIM 120809/30.04.2008 Patent – Dan Sabau) associated with the remarkable performances of the fragmentation device for hydatid cyst content (OSIM Patent no. 120810/30.04.2008 - Dan Sabau) is the best way to approach these problems, accessible for surgeons with minimum experience in laparoscopic and thoracic surgery. The relatively low number of cases allows only the formulation of preliminary positive conclusions on the method; they are to be validated by subsequent results

An Economic Model of Permission Marketing: Win-win-win Relationship Building Among Marketers, ISPs, and Internet Users

A model is proposed for ISP customers to accept e-mail marketing in exchange for a discount on the Internet fee. Adherence to the model appeared to vary with age, number of e-mails received per day, and with the amount of the current fee. Authors recommend marketers send fewer, better-targeted, and personalized e-mails