Unstable Galaxy Models

The dynamics of collisionless galaxy can be described by the Vlasov-Poisson system. By the Jean's theorem, all the spherically symmetric steady galaxy models are given by a distribution of {\Phi}(E,L), where E is the particle energy and L the angular momentum. In a celebrated Doremus-Feix-Baumann Theorem, the galaxy model {\Phi}(E,L) is stable if the distribution {\Phi} is monotonically decreasing with respect to the particle energy E. On the other hand, the stability of {\Phi}(E,L) remains largely open otherwise. Based on a recent abstract instability criterion of Guo-Lin, we constuct examples of unstable galaxy models of f(E,L) and f(E) in which f fails to be monotone in E

On the asymptotic behavior of the contaminated sample mean

An observation of a cumulative distribution function $F$ with finite variance is said to be contaminated according to the inflated variance model if it has a large probability of coming from the original target distribution $F$, but a small probability of coming from a contaminating distribution that has the same mean and shape as $F$, though a larger variance. It is well known that in the presence of data contamination, the ordinary sample mean looses many of its good properties, making it preferable to use more robust estimators. From a didactical point of view, it is insightful to see to what extent an intuitive estimator such as the sample mean becomes less favorable in a contaminated setting. In this paper, we investigate under which conditions the sample mean, based on a finite number of independent observations of $F$ which are contaminated according to the inflated variance model, is a valid estimator for the mean of $F$. In particular, we examine to what extent this estimator is weakly consistent for the mean of $F$ and asymptotically normal. As classical central limit theory is generally inaccurate to cope with the asymptotic normality in this setting, we invoke more general approximate central limit theory as developed by Berckmoes, Lowen, and Van Casteren (2013). Our theoretical results are illustrated by a specific example and a simulation study.Comment: 14 pages, 1 figur

New Congruences Modulo 2, 4, and 8 for the Number of Tagged Parts Over the Partitions with Designated Summands

Recently, Lin introduced two new partition functions PD$_t(n)$ and PDO$_t(n)$, which count the total number of tagged parts over all partitions of $n$ with designated summands and the total number of tagged parts over all partitions of $n$ with designated summands in which all parts are odd. Lin also proved some congruences modulo 3 and 9 for PD$_t(n)$ and PDO$_t(n)$, and conjectured some congruences modulo 8. Very recently, Adansie, Chern, and Xia found two new infinite families of congruences modulo 9 for PD$_t(n)$. In this paper, we prove the congruences modulo 8 conjectured by Lin and also find many new congruences and infinite families of congruences modulo some small powers of 2.Comment: 19 page

Minimum Degrees of Minimal Ramsey Graphs for Almost-Cliques

For graphs $F$ and $H$, we say $F$ is Ramsey for $H$ if every $2$-coloring of the edges of $F$ contains a monochromatic copy of $H$. The graph $F$ is Ramsey $H$-minimal if $F$ is Ramsey for $H$ and there is no proper subgraph $F'$ of $F$ so that $F'$ is Ramsey for $H$. Burr, Erdos, and Lovasz defined $s(H)$ to be the minimum degree of $F$ over all Ramsey $H$-minimal graphs $F$. Define $H_{t,d}$ to be a graph on $t+1$ vertices consisting of a complete graph on $t$ vertices and one additional vertex of degree $d$. We show that $s(H_{t,d})=d^2$ for all values $1<d\le t$; it was previously known that $s(H_{t,1})=t-1$, so it is surprising that $s(H_{t,2})=4$ is much smaller. We also make some further progress on some sparser graphs. Fox and Lin observed that $s(H)\ge 2\delta(H)-1$ for all graphs $H$, where $\delta(H)$ is the minimum degree of $H$; Szabo, Zumstein, and Zurcher investigated which graphs have this property and conjectured that all bipartite graphs $H$ without isolated vertices satisfy $s(H)=2\delta(H)-1$. Fox, Grinshpun, Liebenau, Person, and Szabo further conjectured that all triangle-free graphs without isolated vertices satisfy this property. We show that $d$-regular $3$-connected triangle-free graphs $H$, with one extra technical constraint, satisfy $s(H) = 2\delta(H)-1$; the extra constraint is that $H$ has a vertex $v$ so that if one removes $v$ and its neighborhood from $H$, the remainder is connected.Comment: 10 pages; 3 figure

Vibronic effects on electronic spectra and nonadiabatic photophysics. A quantum/classical dynamical approach.

Quantum vibronic effects have a remarkable impact on the lineshape of electronic spectra.1 They can also play an important role in the dynamics of photophysical processes like internal conversions at Conical Intersections or charge and energy transfer in multichromophoric systems. Recent advancements allow a fair description of such effects in rigid (harmonic) molecules in gas phase.1-4 However, in biology and in material science the photoexcited chomophores are usually embedded in a solvent, possibly establishing with them specific interactions, or even in more complex and heterogeneous environments. Moreover, many systems with interesting optical properties are flexible, i.e. the optical transition triggers large-amplitude curvilinear distortions, and this challenges the applicability of harmonic approximation. Trajectory based approaches are very suitable to deal with these scenarios but they neglect quantum nuclear effects. We are currently working with the hope to devise robust hybrid quantum/classical (QC) approaches to merge the potentialities of trajectory based methods and those of the quantum vibronic methods developed for rigid systems in gas phase or implicit solvents.1,5-6 The system is partitioned in two subsystems: a quantum core (the chromophore or just its high-frequency modes) and an environment (which can include also large amplitude motions of the system itself and is treated at a more approximate classical level) and the challenge is the reliable description of their mutual couplings. We will illustrate our recent results with a number of examples ranging from the chiro-otpical properties of flexible conjugated systems (e.g. oligothiophenes) to the nonadiabatic decay of photoexcited DNA nucleobases7 in acqueous solution. 8-12 1. F. Santoro, D. Jacquemin, WIREs Comput Mol Sci 6, 460–486, 2016 2. M. H Beck,. A Jäckle,. G. A Worth, H.-D Meyer,. Physics Report 2000, 324 3. L. S. Cederbaum, E. Gindensperger, and I. Burghardt, Phys. Rev. Lett. 94, 113003, 2005. 4. D. Picconi, F. Avila, R. Improta, A. Lami, F. Santoro, Faraday Discuss, 163, 223, 2013 5. F. Avila, R. Improta, F. Santoro, V. Barone, Phys Chem Chem Phys. 17007, 13, 2011 6. F. Avila, J. Cerezo, J. Soto, R. Improta, F. Santoro, Comp. Chem. Theor. 1040-1041, 328, 2014 7. R. Improta, E. Stendardo, F. Avila, F. Santoro, Chem. Phys. Chem. 15 3320, 2014 8. R. Improta, F. Santoro, L. Blancafort, Chem . Rev 116, 3540 2016 9. D. Padula, F. Santoro, G. Pescitelli RSC Adv. 6, 37928, 116, 3540, 2016 10. J. Cerezo, F. Avila, G. Prampolini, F. Santoro, J. Chem. Theor. Comp. 11, 5810, 2015 11. J. Cerezo, G. Mazzeo, G. Longhi, S. Abbate, F. Santoro J. Phys. Chem. Lett. 7, 4891, 2016 12. Y. Liu, J. Cerezo, N. Lin, X. Zhao, R. Improta, F. Santoro submitted to J. Phys. Chem. Lett.Universidad de Málaga. Cammous de Excelencia Internacional Andalucía Tech

Medical Literary Messenger (Vol. 5, No. 1, Fall/Winter 2017)

Home Visit / Melissa Fournier -- Stiffness / Hannah Shea -- Exile / Lane Falcon -- Good Intentions / Laura Foley -- Resurrection / Les Cohen -- Visits / Craig W. Steele -- That Last Night / Laura Foley -- Taste / Dan Campion -- Bumblebees Don’t Always Sting / Diane M. Parker -- Mental Status Exam / Melissa Fournier -- Dystrophia I / Ashley Purdy -- Muck Out / Mitchell Krockmalnik Grabois -- Endoscope / Lane Falcon -- Leftovers / Erynn Porter -- Another Autumn / Deborah Fleming -- Autism / Laura Foley -- Nearly Sunset / Craig W. Steele -- Palms / Mitchell Krockmalnic Grabois -- concentric / Michele Riedel -- Hashimoto’s / Hannah Shea -- Uncharted Territory / Katacha Díaz -- Skeletal Survey / Melissa Fournier -- Humanism in Medicine: Reflections from Diastole / Helen Lin -- Late Voyage / Laura Foley -- Sponge Bath / Dan Campion

Egy specializált növényi szerv, a szimbiotikus gyökérgümő kialakulásához kapcsolódó folyamatok funkcionális genomikai vizsgálata. = Functional genomic analysis of the symbiotic root nodule organogenesis.

A nitrogénkötő szimbiózis kialakulása során a pillangós virágú növényeken egy új szerv, a gyökérgümő jön létre, melyben az endoszimbionta baktériumok redukálják a légköri nitrogént a növény számára. A lucernával rokon Medicago truncatula modellnövényt vizsgáljuk, hogy megismerjük ennek a biológiai folyamatnak a molekuláris hátterét. A pályázaton belül egy szimbiotikus génnek (Lin) a mutáns fenotípus térképezésén alapuló klónozását és elsődleges leírását vállaltuk. A M. truncatula lin mutáns gyökerén a szimbionta baktérium adásakor a kezdeti növényi válaszreakciók indukálódnak, a sejtosztódás következtében a gümőprimordium kialakul a belső kéregsejtekből. A baktériumok bejutnak a gyökérszőrbe, azonban az infekció elhal a gyökér epidermiszben. A mutációt szenvedett génnek tehát elengedhetetlen funkciója van a gyökérgümő kialakulásában. Genetikai térképezéssel a mutációt helyét az egyes kapcsoltsági csoporton a DSI és SCP nevű molekuláris markerek között határoztuk meg. E két markert használtuk kiindulási pontként a genomsétához, melynek révén eljutottunk a mutációt hordozó régió meghatározásához, fizikai térképezéséhez, szekvenálásához. A lin mutációt egy ~ 1500 aminosav hosszúságú fehérjét kódoló génben azonosítottuk. A kódolt fehérje hordoz egy ún. U-box domént, mely szerint feltételezhető a fehérje ubiquitin ligáz aktivitása. Ezáltal a LIN fehérje feltételezett funkciója egy, a szimbiózis kialakulásában még nem vizsgált út, az ubiquitinációs folyamatok fontosságára mutat rá. | Symbiotic root nodules are special organs developed on the roots of legume plants upon rhizobial inoculation, in which biological nitrogen fixation takes place. We use the model legume Medicago truncatula as an object to acquire more information about the molecular background of this biological process. We have used positional cloning to isolate a new symbiotic gene playing important role in the nodule organogenesis as well as in the bacterial invasion Medicago truncatula. The M. truncatula lin (lumpy infections) mutant, defective in intermediate steps of nodule differentiation, has been identified as an EMS mutant of line Jemalong A17. This mutant is characterized by a 4-fold reduction in the number of infections, all of which arrest in the root epidermis, and by nodule primordia that initiate normally but fail to mature. For genetic mapping lin a mapping population was generated and the map position of lin has been determined between markers DSI and SCP on Linkage Group 1. These molecular markers were used to start the physical mapping and genome walking towards lin. The genomic region carrying the mutated gene was delimited by the help of recombinants, followed by sequencing. Sequence analyses revealed many candidate genes among which the lin mutation was identified in a gene coding for a large protein of ~ 1500 AA. Based on strong sequence homology the LIN protein contains a U-box domain and thereby is predicted to act as an E3 ubiquitin ligase

Student Chamber Music Concert, November 27, 1990

This is the concert program of the Student Chamber Music Concert performance on Tuesday, November 27, 1990 at 6:30 p.m., at the Boston University Concert Hall, 855 Commonwealth Avenue, Boston, Massachusetts. Works performed were Quartet in B-flat major, K. 458, "The Hunt" by Wolfgang Amadeus Mozart, Duo pour Basson et Contrebasse by Albert Roussel, Quartet in G major, Op. 76, No. 4 by Joseph Haydn, Quartet in f minor, Op. 95 by Ludwig van Beethoven, The Wonderland Duets for two tubas and narrator by Raymond Ludeke, and Octet in F major, Op. 166 by Franz Schubert. Digitization for Boston University Concert Programs was supported by the Boston University Humanities Library Endowed Fund