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Search Results: 1 - 10 of 175312 matches for " E. Bruno "
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Teacher Absenteeism in Urban Schools
James E. Bruno
Education Policy Analysis Archives , 2002,
Abstract: School reform efforts aimed at promoting equity and excellence at urban school settings are heavily dependent upon the quality of teaching personnel that are used to deliver the instructional program. Social Justice and other public policy issues related to equity and excellence at urban schools have begun to examine the impact that teacher absenteeism, and by extension the reliance on substitute teachers to deliver instructional might have on educational attainment. This study combines school district data gathering mechanisms on teacher absence rates at school sites with Geographical Information Systems (G.I.S.) to map the association between a school's geographical environmental space and the propensity for teacher absence. The disparity between teaching resources as delivered by the school district vs. teacher resources as actually received by students in the classroom via teacher absenteeism is examined in the context of schools located in positive (high income) and negative (low income) geographical space. The study concludes that there is a strong association between the geographical quality of the school site setting, teacher absenteeism, and the reliance on substitute teachers to deliver instructional programs. Disparity in teacher absenteeism rates across large urban geographical areas threatens the promotion of equity and excellence in the schools by attenuating or lessening the effect of school resources to support instruction and amplifying the risk factors of students in the classroom.
Blast-wave analysis of strange particle $m_T$ spectra in Pb-Pb collisions at the SPS
G. E. Bruno
Physics , 2004, DOI: 10.1088/0954-3899/31/4/015
Abstract: The transverse mass spectra of high statistics, high purity samples of K0s, Lambda, Xi and Omega particles produced in Pb-Pb collisions at SPS energy have been studied in the framework of the blast-wave model. The dependence of the freeze-out parameters on particle species and event centrality is discussed. Results at 40 A GeV/c are presented here for the first time.
Studio della produzione di particelle strane e della dinamica di espansione in collisioni nucleari ultra-relativistiche all'SPS
G. E. Bruno
Physics , 2004,
Abstract: This is my Ph.D thesis on hyperon production, HBT correlation between negative pions and blast-wave analysis of m_t spectra in Pb-Pb collisions at SPS.
Transverse mass distributions of strange particles produced in Pb-Pb collisions at 158 A GeV/c
G. E. Bruno
Physics , 2003,
Abstract: Experiment NA57 has collected high statistics, high purity samples of $K^0_s$, $\Lambda$, $\Xi$ and $\Omega$ produced in Pb-Pb collisions at 158 $A$ GeV/$c$. In this paper we present a study of the transverse mass spectra of these particles for a sample of events corresponding to about the most central 55% of the inelastic Pb-Pb cross section. We analyse the transverse mass distributions in the framework of the blast-wave model for the full sample under consideration and, for the first time at the SPS, as a function of the event centrality.
The symmetric square of a curve and the Petri map
A. Bruno,E. Sernesi
Mathematics , 2011,
Abstract: Let $\M_g$ be the course moduli space of complex projective nonsingular curves of genus $g$. We prove that when the Brill-Noether number $\rho(g,1,n)$ is non-negative the Petri locus $P^1_{g,n}\subset \M_g$ has a divisorial component whose closure has a non-empty intersection with $\Delta_0$. In order to prove the result we show that the scheme $G^1_n(\Gamma)$ that parametrizes degree $n$ pencils on a curve $\Gamma$ is isomorphic to a component of the Hilbert scheme parametrizing certain curves on the symmetric square $\Gamma_2$ of $\Gamma$ and we study the properties of such a family of curves.
The Influence of 3′UTRs on MicroRNA Function Inferred from Human SNP Data
Zihua Hu,Andrew E. Bruno
Comparative and Functional Genomics , 2011, DOI: 10.1155/2011/910769
Abstract: MicroRNAs (miRNAs) regulate gene expression posttranscriptionally. Although previous efforts have demonstrated the functional importance of target sites on miRNAs, little is known about the influence of the rest of 3′ untranslated regions (3′UTRs) of target genes on microRNA function. We conducted a genome-wide study and found that the entire 3′UTR sequences could also play important roles on miRNA function in addition to miRNA target sites. This was evidenced by the fact that human single nucleotide polymorphisms (SNPs) on both seed target region and the rest of 3′UTRs of miRNA target genes were under significantly stronger negative selection, when compared to non-miRNA target genes. We also discovered that the flanking nucleotides on both sides of miRNA target sites were subject to moderate strong selection. A local sequence region of ~67 nucleotides with symmetric structure is herein defined. Additionally, from gene expression analysis, we found that SNPs and miRNA target sites on target sequences may interactively affect gene expression.
The Influence of 3′UTRs on MicroRNA Function Inferred from Human SNP Data
Zihua Hu,Andrew E. Bruno
International Journal of Genomics , 2011, DOI: 10.1155/2011/910769
Abstract: MicroRNAs (miRNAs) regulate gene expression posttranscriptionally. Although previous efforts have demonstrated the functional importance of target sites on miRNAs, little is known about the influence of the rest of 3′ untranslated regions (3′UTRs) of target genes on microRNA function. We conducted a genome-wide study and found that the entire 3′UTR sequences could also play important roles on miRNA function in addition to miRNA target sites. This was evidenced by the fact that human single nucleotide polymorphisms (SNPs) on both seed target region and the rest of 3′UTRs of miRNA target genes were under significantly stronger negative selection, when compared to non-miRNA target genes. We also discovered that the flanking nucleotides on both sides of miRNA target sites were subject to moderate strong selection. A local sequence region of ~67 nucleotides with symmetric structure is herein defined. Additionally, from gene expression analysis, we found that SNPs and miRNA target sites on target sequences may interactively affect gene expression. 1. Introduction miRNAs are small noncoding RNAs of ~23 nucleotides. They are one of the major regulatory gene families playing important roles in almost every cellular process in animals, plants and viruses [1–3]. In animals, this includes regulation of developmental timing and signaling pathways, apoptosis, metabolism, myogenesis and cardiogenesis, brain development [1], and human pathologies [4–6]. It is believed that miRNAs mainly mediate gene regulation posttranscriptionally via translational repression and reduction of mRNA stability by forming miRNA-mRNA pairs to their target genes. In vertebrates, most miRNAs pair imperfectly with their target 3′UTRs, with a contiguous and perfect base pairing of the miRNA nucleotides 2–7 or 2–8 in the “seed” region. The miRNA seed target region on target gene, which is very important for target recognition, provides pairing specificity [7–9] for translational suppression. However, these seed matches are not always sufficient for repression. The degree of repression might also be related to other features on target 3′UTRs, including AU-rich nucleotide composition of 3′UTR [10] or AU-rich nucleotide composition near miRNA target sites [11], the location of miRNA target sites on 3′UTRs [11–13], the site accessibility in miRNA target recognition [14–16], and base pairing pattern outside seed target region [11]. SNPs are an abundant form of genome variation. Although most SNPs have little or no effect on gene regulation and protein activity, there are many circumstances where
First measurement of the strange particles Rcp nuclear modification factors in heavy-ion collisions at the SPS
G. E. Bruno,A. Dainese
Physics , 2005, DOI: 10.1556/APH.27.2006.2-3.7
Abstract: The NA57 experiment has measured the pt distributions of K0s, Lambda, and antiLambda particles in fixed-target Pb-Pb interactions at sqrt(s_{NN})=17.3 GeV as a function of the collision centrality. In this paper we study the central-to-peripheral nuclear modification factors and compare them to other measurements and to theoretical predictions.
Embryonic, Larval, and Juvenile Development of the Sea Biscuit Clypeaster subdepressus (Echinodermata: Clypeasteroida)
Bruno C. Vellutini,Alvaro E. Migotto
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0009654
Abstract: Sea biscuits and sand dollars diverged from other irregular echinoids approximately 55 million years ago and rapidly dispersed to oceans worldwide. A series of morphological changes were associated with the occupation of sand beds such as flattening of the body, shortening of primary spines, multiplication of podia, and retention of the lantern of Aristotle into adulthood. To investigate the developmental basis of such morphological changes we documented the ontogeny of Clypeaster subdepressus. We obtained gametes from adult specimens by KCl injection and raised the embryos at 26C. Ciliated blastulae hatched 7.5 h after sperm entry. During gastrulation the archenteron elongated continuously while ectodermal red-pigmented cells migrated synchronously to the apical plate. Pluteus larvae began to feed in 3 d and were 20 d old at metamorphosis; starved larvae died 17 d after fertilization. Postlarval juveniles had neither mouth nor anus nor plates on the aboral side, except for the remnants of larval spicules, but their bilateral symmetry became evident after the resorption of larval tissues. Ossicles of the lantern were present and organized in 5 groups. Each group had 1 tooth, 2 demipyramids, and 2 epiphyses with a rotula in between. Early appendages consisted of 15 spines, 15 podia (2 types), and 5 sphaeridia. Podial types were distributed in accordance to Lovén's rule and the first podium of each ambulacrum was not encircled by the skeleton. Seven days after metamorphosis juveniles began to feed by rasping sand grains with the lantern. Juveniles survived in laboratory cultures for 9 months and died with wide, a single open sphaeridium per ambulacrum, aboral anus, and no differentiated food grooves or petaloids. Tracking the morphogenesis of early juveniles is a necessary step to elucidate the developmental mechanisms of echinoid growth and important groundwork to clarify homologies between irregular urchins.
Constitutive Activation of PrfA Tilts the Balance of Listeria monocytogenes Fitness Towards Life within the Host versus Environmental Survival
Joseph C. Bruno Jr,Nancy E. Freitag
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0015138
Abstract: PrfA is a key regulator of Listeria monocytogenes pathogenesis and induces the expression of multiple virulence factors within the infected host. PrfA is post-translationally regulated such that the protein becomes activated upon bacterial entry into the cell cytosol. The signal that triggers PrfA activation remains unknown, however mutations have been identified (prfA* mutations) that lock the protein into a high activity state. In this report we examine the consequences of constitutive PrfA activation on L. monocytogenes fitness both in vitro and in vivo. Whereas prfA* mutants were hyper-virulent during animal infection, the mutants were compromised for fitness in broth culture and under conditions of stress. Broth culture prfA*-associated fitness defects were alleviated when glycerol was provided as the principal carbon source; under these conditions prfA* mutants exhibited a competitive advantage over wild type strains. Glycerol and other three carbon sugars have been reported to serve as primary carbon sources for L. monocytogenes during cytosolic growth, thus prfA* mutants are metabolically-primed for replication within eukaryotic cells. These results indicate the critical need for environment-appropriate regulation of PrfA activity to enable L. monocytogenes to optimize bacterial fitness inside and outside of host cells.
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