304 research outputs found
Linear control analysis of the autocatalytic glycolysis system
Autocatalysis is necessary and ubiquitous in both
engineered and biological systems but can aggravate control
performance and cause instability. We analyze the properties of
autocatalysis in the universal and well studied glycolytic
pathway. A simple two-state model incorporating ATP
autocatalysis and inhibitory feedback control captures the
essential dynamics, including limit cycle oscillations, observed
experimentally. System performance is limited by the inherent
autocatalytic stoichiometry and higher levels of autocatalysis
exacerbate stability and performance. We show that glycolytic
oscillations are not merely a "frozen accident" but a result of
the intrinsic stability tradeoffs emerging from the autocatalytic
mechanism. This model has pedagogical value as well as
appearing to be the simplest and most complete illustration yet
of Bode’s integral formula
Recommendations for Medical Education in Taiwan
The purpose of the new project presented in these pages is to offer an innovative approach to the study of the evolution of Coptic literature and, more specifically, to the corpus of writings produced in Egypt between the third and the late eleventh centuries, and expressed in the different dialects of the Coptic language. Its aim is to provide a new perspective on the cultural landscape of Christian Egypt by interweaving literary, historical, codicological and archaeological data, and producing a series of scholarly tools, till now unavailable, in a digital environment, including an archaeological Atlas of late antique and early mediaeval Coptic literature that will be searchable at different chronological, regional and thematic levels.
As part of the above-described research activities and goals, a complete catalogue of the Coptic papyrus codices preserved in the Museo Egizio will be produced, as well as an edition of their titles and scribal subscriptions. The fragmentary codices in question, purchased in Egypt by Bernardino Drovetti in the 1820s, are a unique example of an entire well-preserved late antique institutional library – very likely originally belonging to the cathedral of This/Thinis – reflecting the literary tastes and dogmatic orientations before what can be defined as the ninth-century Coptic book revolution, which significantly changed bookmaking in Christian Egypt. The library of Thi(ni)s is a crucial and transitional instance in the history of Coptic books, which saw on the one hand the creation of new codicological and palaeographical features and on the other the progressive emergence of multiple-text codices
Fundamental Limits and Tradeoffs in Autocatalytic Pathways
This paper develops some basic principles to study autocatalytic networks and exploit their structural properties in order to characterize their inherent fundamental limits and tradeoffs. In a dynamical system with autocatalytic structure, the system's output is necessary to catalyze its own production. Our study has been motivated by a simplified model of a glycolysis pathway. First, the properties of this class of pathways are investigated through a network model, which consists of a chain of enzymatically catalyzed intermediate reactions coupled with an autocatalytic component. We explicitly derive a hard limit on the minimum achievable L₂-gain disturbance attenuation and a hard limit on its minimum required output energy. Then, we show how these resulting hard limits lead to some fundamental tradeoffs between transient and steady-state behavior of the network and its net production
In situ observations on the dentition and oral cavity of the Neanderthal skeleton from Altamura (Italy)
The Neanderthal specimen from Lamalunga Cave, near Altamura (Apulia, Italy), was discovered during a speleological survey in 1993. The specimen is one of the most complete fossil hominins in Europe and its state of preservation is exceptional, although it is stuck in calcareous concretions and the bones are mostly covered by calcite depositions. Nevertheless, it is possible to carry out some observations on craniodental features that have not previously been described. In this work, we present an account of the oral cavity, made possible by the use of a videoscope, which allowed us to reach some hidden parts of the mandible and palate. This is the first detailed overview of the teeth and maxillary bones of the Neanderthal skeleton from Altamura. The dentition is almost complete. However, two teeth (upper right P3 and upper left M1) were lost ante mortem and four teeth (lower right I1 and P3 and lower left I1 and I2) were lost most probably post mortem. Dental wear is marked. The erupted M3s and the inversion of the compensating curve of Wilson in the M1s and M2s but not in the M3s suggest that the individual is fully adult, but not old. Although most of the teeth have their roots exposed for several millimeters, the periodontal bone appears to be in good condition overall, except in correspondence of the two ante-mortem tooth losses. X-rays of the anterior teeth show a periapical lesion, probably linked to the advanced dental wear. We also observed a weak expression of taurodontism in the posterior dentition and the presence of a retromolar space, features consistent with an attribution to the Neanderthal hypodigm; this attribution is also supported by aspects of the cranial morphology, the morphometric analysis of the scapula and preliminary mtDNA data. There is also a well-developed palatine torus, to the best of our knowledge a feature not previously described in Neanderthals
Treatment of GH-deficient children with two different GH doses: effect on final height and cost-benefit implications
OBJECTIVE: Treatment of GH-deficient (GHD) children with higher doses of recombinant human GH (rhGH) than conventional ones has been reported to result in higher growth velocity and increased final height. These findings, however, were observed by comparing large but heterogeneous groups of children. We wanted to verify whether the same results could be obtained in two groups of appropriately well-matched children with isolated GHD treated with high vs conventional doses of rhGH. METHODS: Out of two cohorts of GHD children, cohort A (on a weekly rhGH dose of 0.3 mg/kg body weight) and cohort B (on a weekly rhGH dose of 0.15 mg/kg body weight), we selected two groups, each including 13 patients, who before treatment were matched for age, sex and height standard deviation score (SDS). They were followed up until final height. RESULTS: Final height SDS was significantly higher in group A (-0.45+/-0.36 (s.d.) vs -1.07+/-0.7; P=0.008), as well as height gain SDS (1.81+/-0.58 vs 1.23+/-0.62; P=0.002). The difference between final height SDS and target height SDS was positive only in group A and significantly higher in group A than in group B (0.33+/-0.51 vs -0.46+/-0.7; P=0.01). Glucose tolerance was always normal in the group treated with higher doses. CONCLUSION: The final height of children treated with higher doses of rhGH is increased, also in relation to their genetic target. The economical burden of this choice of treatment, however, has to be taken into account when evaluating the results
Fundamental Limits and Tradeoffs in Autocatalytic Pathways
This paper develops some basic principles to study autocatalytic networks and exploit their structural properties in order to characterize their inherent fundamental limits and tradeoffs. In a dynamical system with autocatalytic structure, the system's output is necessary to catalyze its own production. Our study has been motivated by a simplified model of a glycolysis pathway. First, the properties of this class of pathways are investigated through a network model, which consists of a chain of enzymatically catalyzed intermediate reactions coupled with an autocatalytic component. We explicitly derive a hard limit on the minimum achievable L₂-gain disturbance attenuation and a hard limit on its minimum required output energy. Then, we show how these resulting hard limits lead to some fundamental tradeoffs between transient and steady-state behavior of the network and its net production
Menstrual pattern and menstrual disorders among adolescents: an update of the Italian data.
Abstract Background The most striking event in the whole process of female puberty is the onset of menstruation. To our knowledge, no large population-based studies have been performed on the topic of menstrual health among Italian adolescents in recent years. The aims of this study were to produce up-to-date information on the menstrual pattern of Italian girls attending secondary school, and to estimate the prevalence of menstrual cycle abnormalities in this population. Methods This was a cross-sectional study on a population-based sample of Italian adolescents aged 13–21 years attending secondary school. Only girls who had already started menstruating were requested to participate. Information was collected by means of a questionnaire that included items on the girls’ demographic details, anthropometrics, smoking and drinking habits, use of contraceptive pills, and socioeconomic status. The questions on the girls’ menstrual pattern concerned their age at menarche, duration of the most recent menstruation intervals (35 days, variable), average days of bleeding (6 days), and any menstrual problems and their frequency. Results A total of 6,924 questionnaires were administered and 4,992 (71%) were returned. One hundred girls failed to report their date of birth, so 4,892 subjects were analyzed. The girls’ mean age was 17.1 years (SD ±1.4); their mean age at menarche was 12.4 (±1.3) years, median 12.4 years (95%CI 12.3–12.5). In our sample population, 3.0% (95%CI 2.5%-3.4%) of the girls had menstruation intervals of less than 21 days, while it was more than 35 days in 3.4% (95%CI 2.9%-3.9%). About 9% of the girls (95%CI 7.7%-9.4%) said the length of their menstruation interval was currently irregular. Short bleeding periods (6 days) in 19% (95%CI 17.9%-20.1%). Menstruation-related abdominal pain was reported by about 56% of our sample. About 6.2% of the girls (95%CI 5.4%-7.0%) were suffering from dysmenorrhea. Conclusions In conclusion, to the best of our knowledge, this is one of the largest studies on menstrual patterns and menstrual disorders among Italian adolescent girls. Adolescent girls referring persistent oligomenorrhoea, in first two years from menarche, had a higher risk for developing a persistent menstrual irregularity. They had longer bleeding periods (>6 days) and this has practical implications because it makes these adolescents potentially more susceptible to iron deficiency anemia. Clinicians need to identify menstrual abnormalities as early as possible in order to minimize their possible consequences and sequelae, and to promote proper health information. We recommend that adolescents should be encouraged to chart their menstrual frequency and regularity prospectively from the menarche onwards.</p
Measuring the CMB primordial B-modes with Bolometric Interferometry
The Q&U Bolometric Interferometer for Cosmology (QL’BIC) is the first bolometric interferometer designed to measure the primordial B-mode polarization of the Cosmic Microwave Background (CMB). Bolometric interferometry is a novel technique that combines the sensitivity of bolometric detectors with the control of systematic effects that is typical of interferometry, both key features in the quest for the faint signal of the primordial B-modes. A unique feature is the so-called “spectral imaging”, i.e., the ability to recover the sky signal in several sub-bands within the physical band during data analysis. This feature provides an in-band spectral resolution of ∆v/v ~ 0.04 that is unattainable by a traditional imager. This is a key tool for controlling the Galactic foregrounds contamination. In this paper, we describe the principles of bolometric interferometry, the current status of the QU BIC experiment and future prospects.Fil: Mennella, A.. Università degli Studi di Milano; Italia. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Ade, P.. Cardiff University; Reino UnidoFil: Almela, Daniel Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Tecnología en Detección y Astropartículas. Comisión Nacional de Energía Atómica. Instituto de Tecnología en Detección y Astropartículas. Universidad Nacional de San Martín. Instituto de Tecnología en Detección y Astropartículas; ArgentinaFil: Amico, G.. Università di Roma; ItaliaFil: Arnaldi, Luis Horacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Tecnología en Detección y Astropartículas. Comisión Nacional de Energía Atómica. Instituto de Tecnología en Detección y Astropartículas. Universidad Nacional de San Martín. Instituto de Tecnología en Detección y Astropartículas; ArgentinaFil: Aumont, J.. Institut de Recherche en Astrophysique et Planétologie; FranciaFil: Banfi, S.. Università degli Studi di Milano; Italia. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Battistelli, E. S.. Istituto Nazionale di Fisica Nucleare; Italia. Università degli Studi di Milano; ItaliaFil: Bélier, B.. Centre de Nanosciences et de Nanotechnologies; FranciaFil: Bergé, L.. Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse; FranciaFil: Bernard, J.. Institut de Recherche en Astrophysique et Planétologie; FranciaFil: Bersanelli, M.. Università degli Studi di Milano; Italia. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Bonaparte, J.. Comisión Nacional de Energía Atómica. Centro Atómico Constituyentes; ArgentinaFil: Bonilla Neira, Jesús David. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Tecnología en Detección y Astropartículas. Comisión Nacional de Energía Atómica. Instituto de Tecnología en Detección y Astropartículas. Universidad Nacional de San Martín. Instituto de Tecnología en Detección y Astropartículas; ArgentinaFil: Bunn, E.. University of Richmond; Estados UnidosFil: Buzi, D.. Università di Roma; ItaliaFil: Cacciotti, F.. Università di Roma; Italia. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Camilieri, D.. Universite de Paris; Francia. Centre National de la Recherche Scientifique; FranciaFil: Cavaliere, F.. Università di Roma; Italia. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Chanial, P.. Universite de Paris; Francia. Centre National de la Recherche Scientifique; FranciaFil: Chapron, C.. Universite de Paris; Francia. Centre National de la Recherche Scientifique; FranciaFil: Colombo, L.. Università degli Studi di Milano; Italia. Istituto Nazionale di Fisica Nucleare; ItaliaFil: Gomez Berisso, Mariano. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro. Archivo Histórico del Centro Atómico Bariloche e Instituto Balseiro | Universidad Nacional de Cuyo. Instituto Balseiro. Archivo Histórico del Centro Atómico Bariloche e Instituto Balseiro; ArgentinaFil: Tucker, G.. University of Wisconsin; Estados UnidosFil: Tucker, C.. Cardiff University; Reino UnidoFil: Vacher, L.. Centre National de la Recherche Scientifique; Francia. Institut de Recherche en Astrophysique et Planétologie; FranciaFil: Voisin, F.. Centre National de la Recherche Scientifique; Francia. Universite de Paris; FranciaFil: Wright, M.. University of Manchester; Reino UnidoFil: Zannoni, M.. Istituto Nazionale di Fisica Nucleare; Italia. Università degli Studi di Milano; ItaliaFil: Zullo, A.. Istituto Nazionale di Fisica Nucleare; Itali
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