1,251 research outputs found
Hilbert curves of quadric fibrations
Let (X,L) be a quadric fibration over a smooth curve.
The explicit equation of the corresponding Hilbert curve \Gamma is obtained.
The geometry of \Gamma reflects some structure properties of (X,L); in particular,
its special shape allows us to recognize that (X,L) is a quadric fibration. In fact \Gamma
is reducible into \dim X -2 parallel lines with prescribed slope, evenly spaced,
plus a conic. On the other hand, this conic can itself be regarded
as the Hilbert curve of a polarized surface only in very rare circumstances
Inflectional loci of scrolls
Let be a scroll over a smooth curve and let
\L=\mathcal O_{\mathbb P^N}(1)|_X denote the hyperplane bundle. The special
geometry of implies that some sheaves related to the principal part bundles
of \L are locally free. The inflectional loci of can be expressed in
terms of these sheaves, leading to explicit formulas for the cohomology classes
of the loci. The formulas imply that the only uninflected scrolls are the
balanced rational normal scrolls.Comment: 9 pages, improved version. Accepted in Mathematische Zeitschrif
The Economics of Rhetoric: On Metaphors as Institutions
The professional life of economists takes place within the boundaries of the institution of academic economics. Belonging to the in
Isolation and mapping of a C3'H gene (CYP98A49) from globe artichoke, and its expression upon UV-C stress
Globe artichoke represents a natural source of phenolic compounds with dicaffeoylquinic acids along with their biosynthetic precursor chlorogenic acid (5-caffeoylquinic acid) as the predominant molecules. We report the isolation and characterization of a full-length cDNA and promoter of a globe artichoke p-coumaroyl ester 3¿-hydroxylase (CYP98A49), which is involved in both chlorogenic acid and lignin biosynthesis. Phylogenetic analyses demonstrated that this gene belongs to the CYP98 family. CYP98A49 was also heterologously expressed in yeast, in order to perform an enzymatic assay with p-coumaroylshikimate and p-coumaroylquinate as substrates. Real Time quantitative PCR analysis revealed that CYP98A49 expression is induced upon exposure to UV-C radiation. A single nucleotide polymorphism in the CYP98A49 gene sequence of two globe artichoke varieties used for genetic mapping allowed the localization of this gene to linkage group 10 within the previously developed map
Implementation of Reciprocal Teaching Models to Increase the Capability of Writing Definition and Theorem in Simbolic Form
This study aims to obtain objective information about increasing in writing skill about definitions and theorems in symbolic form students through RT models in the sets, all kind of relations and functions in set and logic courses. In addition, this study develop the ability of understanding of definitions and theorems, because the ability of students to write definitions and theorems in symbolic form will foster the ability of understanding of the definitions and theorems.The sample of this study are the first semester students in class A2 who follow sets and logic course in mathematics education program of PMIPA FKIP Untan 2016-2017. Implementation focus on subject, sets and all kind of relations and functions.The data collection conducted in providing achievement test after being given treatment. Form of test is Essai with 15 questions which consist of 4 questions from subject set, 8 questions from kind of relations and 3 questions from functions.The results showed if the Reciprocal Teaching Model is one of model that could improve the writing skill about definitions and theorems through symbolic form in the subject matter ; Sets, kind of relations, functions in Sets and Logic courses
Three-dimensional evaluation of rapid maxillary expansion anchored to primary molars: Direct effects on maxillary arch and spontaneous mandibular response
Aim The purpose of this study was to evaluate the effects of rapid maxillary expansion (RME) on maxillary and mandibular arch in the mixed dentition. Methods Forty-four consecutive patients with transverse maxillary deficiency were recruited. Test group: 21 patients (10 male, 11 female; 7.4 \ub1 1.2 years) who underwent RME (Haas type) therapy banded on the primary second molars. Control group: 17 patients (10 male, 7 female; 7.3 \ub1 1.1 years old) who did not receive any orthodontic treatment. Dental casts obtained pre-treatment and after appliance removal (11 months) were processed by means of a three-dimensional scanner (3Shape D250 laser, DK). Digital landmarks were traced using the VAM software (Canfield Scientific Inc., Fairfield-NJ, USA). Arch Length, interdental width and torque differences were measured before and after the removal of the appliance. The t-test (P < 0.05) for paired data was applied to evaluate the measurements values before and after treatment. The linear regression model was employed to assess the correlations between treatment effects. Results The efficacy of the RME was confirmed both on maxillary and mandibular arch. Mandibular intermolar width (+2.02 mm) together with primary intermolar (+1.39 mm), intercanine width (+0.95mm) and torque variations significantly increased. The untreated control group showed no significant statistical differences between T0 and T1. The linear regression between maxillary and mandibular data showed correlations between the torque of the teeth 16/46 and 65/85 (P < 0.05). Conclusions RME anchored on primary molars is an effective treatment option to correct tranverse maxillary deficiencies. All the measurements increased significantly confirming the indirect effect of RME on the mandibular arch
Optical variability of the BL Lacertae object GC 0109+224. Multiband behaviour and time scales from a 7-years monitoring campaign
We present the most continuous data base of optical
observations ever published on the BL Lacertae object GC 0109+224, collected
mainly by the robotic telescope of the Perugia University Observatory in the
period November 1994-February 2002. These observations have been complemented
by data from the Torino Observatory, collected in the period July 1995-January
1999, and Mt. Maidanak Observatory (December 2000). GC 0109+224 showed rapid
optical variations and six major outbursts were observed at the beginning and
end of 1996, in fall 1998, at the beginning and at the end of 2000, and at the
beginning of 2002. Fast and large-amplitude drops characterized its flux
behaviour. The magnitude ranged from 13.3 (16.16 mJy) to 16.46 (0.8 mJy),
with a mean value of 14.9 (3.38 mJy). In the periods where we collected
multi-filter observations, we analyzed colour and spectral indexes, and the
variability patterns during some flares. The long-term behaviour seems
approximatively achromatic, but during some isolated outbursts we found
evidence of the typical loop-like hysteresis behaviour, suggesting that rapid
optical variability is dominated by non-thermal cooling of a single emitting
particle population. We performed also a statistical analysis of the data,
through the discrete correlation function (DCF), the structure function (SF),
and the Lomb-Scargle periodogram, to identify characteristic times scales, from
days to months, in the light curves, and to quantify the mode of variability.
We also include the reconstruction of the historical light curve and a
photometric calibration of comparison stars, to favour further extensive
optical monitoring of this interesting blazar.Comment: 13 pages, 11 PS figures, 1 EPS figure, 3 tables, accepted by
Astronomy and Astrophysics. Uses A&A documentclass aa.cls, and the package
graphicx.st
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