Two-Sided Derivatives for Regular Expressions and for Hairpin Expressions

The aim of this paper is to design the polynomial construction of a finite recognizer for hairpin completions of regular languages. This is achieved by considering completions as new expression operators and by applying derivation techniques to the associated extended expressions called hairpin expressions. More precisely, we extend partial derivation of regular expressions to two-sided partial derivation of hairpin expressions and we show how to deduce a recognizer for a hairpin expression from its two-sided derived term automaton, providing an alternative proof of the fact that hairpin completions of regular languages are linear context-free.Comment: 28 page

Tertiary remagnetization of Paleozoic rocks from the Eastern Cordillera and sub-Andean Belt of Bolivia

Paleomagnetic samples were collected from 98 sedimentary horizons in eight different Devonian to Permian sedimentary units at eight localities in the Eastern Cordillera and the sub-Andean Belt of Bolivia. For 77 sites, thermal demagnetization allowed determination of a characteristic magnetization (ChRM) with site-mean 95% confidence limit, α95, ≤15°. The ChRM is carried predominantly or entirely by hematite. Fold and reversal tests from two of the sampled localities indicate that the characteristic magnetization is synfolding, likely acquired during the earliest stages of deformation. Additionally, a modified conglomerate test at one locality and the nearly uniform direction of ChRM across the Devonian to Permian age units clearly reveals the secondary nature of the characteristic magnetization. Finally, the ChRM directions are discordant from any expected Paleozoic directions. Paleomagnetic poles calculated from the ChRM directions fall near the Cenozoic portion of the apparent polar wander path for South America. We interpret these observations to indicate widespread chemical remagnetization of these Paleozoic strata during, but prior to completion of, Cenozoic Andean folding

Removal of a mixture of oxygenated VOCs in a biotrickling filter

[Abstract] Laboratory scale-studies on the biodegradation of a 1:1:1 wt mixture of three oxygenated volatile organic compounds (VOCs), ethanol, ethyl acetate and methyl-ethyl ketone (MEK) in a biotrickling filter were carried out using two identically sized columns, filled with different polypropylene rings. The reactors were seeded with a two-month preconditioned culture from activated sludge. The performance of the biotrickling filters was examined for a continuous period of 4 months at VOC concentration from 125 mg-C/m3 to 550 mg-C/m3 and at gas flow rates of around 1.0 m3/h, 2.0 m3/h and 4.6 m3/h, which correspond to gas empty bed residence times (EBRT) of 68 s, 33 s and 16 s, respectively. Similar performance was obtained for both supports. Intermittent flow rate of trickling liquid was shown as beneficial to improve the removal efficiency of the system. A stratification in the substrate consumption was observed from gas composition profiles, with MEK % in the emission greater than 78%. Continuous VOC feeding resulted in an excessive accumulation of biomass and high pressure drop was developed in less than 20-30 days of operation. Intermittent VOC loading with night and weekend feed cut-off periods passing dried air, but without water addition, was shown as a successful operational mode to control the biofilm thickness. In this case, operation at high inlet loads was extended for more than 50 days maintaining high removal efficiencies and low pressure drops

Process intensification for the production of cyclic macrolactones: identification of safe operating conditions in tubular reactors

In this work, the possibility to shift from a batch to a continuous production of 16-hexadecanolide, one of the main components of the white musk essence, was theoretically studied. The selected synthesis was an upgraded version of that proposed by Story in 1968, who obtained macrocyclic compounds from the decomposition of ketone peroxides (in this case the involved peroxide was tricyclohexylidene triperoxide). But such reaction presents some huge criticalities: 1) high exothermicity and, 2) production of carbon dioxide, which are known to both modify the kinetics of the desired reaction and lead to a pressure increase inside the reactor whether the gases are not vented. For such reasons, to implement any safe continuous production of this chemical compound, two main points must be addressed: 1) determination of the system runaway boundaries and 2) identification of the optimal operating conditions to make sustainable the production of 16-hexadecanolide (that is, the theoretical design of a tubular reactor capable of continuously discharging the produced incoercible gases). For what concerns the first point, a sensitivity analysis was carried out to determine the safe operating range of the most important operating variables (that is, coolant temperature and reactant inlet temperature) possibly taking into account the effect of radial dispersion; for the second point, as carbon dioxide is produced over the decomposition and needs to be continuously vented to avoid reactor pressurization, a Teflon tube, highly permeable with respect to carbon dioxide, was proposed and its theoretical performances was investigated trying to maximize 16-hexadecanolide productivity also maintaining safe operating conditions. Results showed the theoretical possibility of developing a continuous production process capable of being also commercially sustainable

Q fever mimicking herpetic encephalitis

We describe a patient with temporal lobe encephalitis associated with primary Coxiella burnetii infection who lsresented with CT and MRI findings suggestive of herpes simplex encephaktis and an initial improvement during treatment with acyclovir. Q fever should be considered in the differential diagnosis of patients whose manifestations suggest herpes encephalitis

A Dust-Penetrated Classification Scheme for Bars as Inferred from their Gravitational Force Fields

The division of galaxies into ``barred'' (SB) and ``normal'' (S) spirals is a fundamental aspect of the Hubble galaxy classification system. This ``tuning fork'' view was revised by de Vaucouleurs, whose classification volume recognized apparent ``bar strength'' (SA, SAB, SB) as a continuous property of galaxies called the ``family''. However, the SA, SAB, and SB families are purely visual judgments that can have little bearing on the actual bar strength in a given galaxy. Until very recently, published bar judgments were based exclusively on blue light images, where internal extinction or star formation can either mask a bar completely or give the false impression of a bar in a nonbarred galaxy. Near-infrared camera arrays, which principally trace the old stellar populations in both normal and barred galaxies, now facilitate a quantification of bar strength in terms of their gravitational potentials and force fields. In this paper, we show that the maximum value, Qb, of the ratio of the tangential force to the mean radial force is a quantitative measure of the strength of a bar. Qb does not measure bar ellipticity or bar shape, but rather depends on the actual forcing due to the bar embedded in its disk. We show that a wide range of true bar strengths characterizes the category ``SB'', while de Vaucouleurs category ``SAB'' corresponds to a much narrower range of bar strengths. We present Qb values for 36 galaxies, and we incorporate our bar classes into a dust-penetrated classification system for spiral galaxies.Comment: Accepted for publication in the Astrophysical Journal (LaTex, 30 pages + 3 figures); Figs. 1 and 3 are in color and are also available at http://bama.ua.edu/~rbuta/bars

Headache of recent onset in adults: a prospective population-based study

One hundred consecutive adult patients with headache of recent onset were prospectively studied. Every patient was examined by craneal CT scan. Their mean age was 46 years (range 17-82). Neurological examination was normal in 80 patients. Organic headache represented 39% of the entire group, and 26% of them had a normal neurological examination. The yield of CT scan in patients with headaches and a normal neurological examination was 22.5% (95% IC: 14%-33%); of which we encountered the following pathologies: intracranial tumors (13), hydrocephalus (2), arachnoid cyst (l), toxoplasmic abscess (1) and parenchymal hemorrhage (1). The clinical characteristics of the headache on their own was insufficient to rule out the possibility of an intracranial tumor. Neuroimaging studies should be performed in all adult patients with non-vascular headache of recent onset, I and previously headache-free individual

¿Es adecuado el sistema español de evaluación de la actividad investigadora para su aplicación a las Ciencias de la Tierra y otros campos afines?

Through the survey «Research activities in the R&D system in Earth Sciences in Spain (1990-1994)>>, information about different aspects of the professional activity of Spanish researchers in this field has been retrieved, as well as their opinion about prevailing research evaluation criteria. Starting from survey's results, we discuss the suitability of the present Spanish scientific evaluation system for assessing research activity of said researchers. Results show scientist's disagreement with the prevailing evaluation procedures and criteria. More than 70 % of both University and CSIC researchers consider that evaluation criteria are inappropriate or unacceptable, being this percentage significantly higher than the obtained from scientists belonging to other institutions. Disagreement with evaluation criteria is significantly lower among authors that only publish in foreign journals. Positive correlation has been found between opinion about evaluation criteria and the level of consolidation and stability of research teams. Main cause of disagreement is concerned with the over-valuation of papers published in SCI journals and the scarce consideration given to high quality papers published in serious domestic journals and to other scientific contributions. Results suggest that the evaluation system could have been detrimental to researchers working in some scientific fields, but does not seem to have discriminate among basic and applied research or among research of local or national interest and those more internationally-oriented. The research evaluation system should consider the idiosyncrasy of the different scientific fields, as well as their particular and distinctive characteristics and dynamics. It should take into the adequate consideration quality scientific work that, despite being of particular importance in fields as Earth Sciences, is not published in SCI joumals.A través de la opinión expresada por los propios investigadores, se discute la idoneidad del actual sistema español de evaluación de la actividad investigadora, para su aplicación en el campo de las Ciencias de la Tierra. Dicha opinión ha sido obtenida a través de la encuesta «Actividades de investigación realizadas en el Sistema de I+D en Ciencias de la Tierra en España, 1990-1994», que recoge información sobre distintos aspectos de la actividad profesional de los investigadores españoles en este campo. Los resultados muestran su desacuerdo con los criterios y el procedimiento de evaluación actualmente vigentes. Más del 70 % tanto de los profesores universitarios como de los investigadores del CSIC considera que los criterios de evaluación son inadecuados o inaceptables, siendo su grado de disconformidad con los mismos significativamente más elevado que el de los investigadores del resto de instituciones. Este porcentaje es significativamente menor entre los científicos que publican exclusivamente en revistas extranjeras. Asimismo, se ha detectado una correlación positiva entre la opinión acerca de los criterios de evaluación y el nivel de consolidación y estabilidad de los equipos de investigación, de modo que cuanto mayor es éste más elevada es la proporción de juicios favorables a los mismos. El principal motivo de disconformidad con el procedimiento de evaluación se refiere a la excesiva importancia que se concede a los trabajos publicados en revistas del SCI, en detrimento de los publicados en revistas españolas de calidad y de otras contribuciones científicas. Los resultados indican que el sistema de evaluación podría estar produciendo una discriminación entre los investigadores pertenecientes a distintos campos científicos, más que entre investigación básica y aplicada o entre investigación de interés local y/o nacional y aquella de ámbito internacional. Consideramos que el sistema de evaluación debe tener en cuenta la idiosincrasia y características propias y distintivas de cada campo científico y debe tomar en la adecuada consideración los trabajos de contrastada calidad que, por diversos motivos, no se publican en revistas del SCI, los cuales tienen una especial importancia en ciertos campos científicos, entre los que se encuentran las Ciencias de la Tierra