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Selected Bibliography from the Special Collections Department of The College of The Bahamas Library
Gottardi, Angela,Gottardi, Angela
College Forum , 1997,
Abstract: In the Special Collections Department of The College of The Bahamas Library resides a little treasure trove of resources pertaining to The Bahamas, the West Indies and Africa. These collections hold a variety of printed materials: books, dissertations, research studies, government documents, journals, newspaper clippings and ephemera. The Bahamian Collection is the most extensive. Established in 1984, it serves the purpose of a research depository for The Bahamas, as the National Library is yet to be built. Officially, the National Archives is the depository for the historical records of the country. The Bahamas is fortunate in having a very fine archival institution, located on Mackey Street. Titles included in the Bahamian Collection Selected Bibliography are books chosen for their representational appeal. The intention was to represent a cross-section of publications highlighting all aspects of The Bahamas. That was the primary criterion. The other consideration was motivational value. By this is meant the ability to tantalize the reader into discovering more about whom, why and what has been printed to preserve, inform, entertain and contemplate the fascinating evolution of The Bahamas. Owing to the strong oral tradition of the country, the printed record of the people began somewhat later than in many other cultures. This too is of significance to the interested reader. In August 1996 when I came to work at The College of The Bahamas as the Special Collections Librarian, I knew nothing of the colors, textures and vitality of this country. A Fodor's travel guide provided factual information and description and some enticing photographs. The context of Bahamian life was a mystery to me. As the authors of the books selected for this bibliography, I have grown more and more intrigued by this island archipelago. Thanks to the encoded voice of natives and, like myself, windblown curious wanderers who have had the good fortune to arrive, if only for a short while, and partake, a cache of Bahamian wealth has been shared. This is a reader's bibliography and a work unto itself. It is not meant to support a work of research or any other work. The format used for this bibliography is presented in the following manner: title (in bold italics), author, publication information. This style is a deliberate departure from that of APA to which other articles in this publication of College Forum are required to conform.
Complete model of a spherical gravitational wave detector with capacitive transducers. Calibration and sensitivity optimization
Luciano Gottardi
Physics , 2006, DOI: 10.1103/PhysRevD.75.022002
Abstract: We report the results of a detailed numerical analysis of a real resonant spherical gravitational wave antenna operating with six resonant two-mode capacitive transducers read out by superconducting quantum interference devices (SQUID) amplifiers. We derive a set of equations to describe the electro-mechanical dynamics of the detector. The model takes into account the effect of all the noise sources present in each transducer chain: the thermal noise associated with the mechanical resonators, the thermal noise from the superconducting impedance matching transformer, the back-action noise and the additive current noise of the SQUID amplifier. Asymmetries in the detector signal-to-noise ratio and bandwidth, coming from considering the transducers not as point-like objects but as sensor with physically defined geometry and dimension, are also investigated. We calculate the sensitivity for an ultracryogenic, 30 ton, 2 meter in diameter, spherical detector with optimal and non-optimal impedance matching of the electrical read-out scheme to the mechanical modes. The results of the analysis is useful not only to optimize existing smaller mass spherical detector like MiniGrail, in Leiden, but also as a technological guideline for future massive detectors. Furthermore we calculate the antenna patterns when the sphere operates with one, three and six resonators. The sky coverage for two detectors based in The Netherlands and Brasil and operating in coincidence is also estimated. Finally, we describe and numerically verify a calibration and filtering procedure useful for diagnostic and detection purposes in analogy with existing resonant bar detectors.
On the Sensitivity of a Hollow Sphere as a Multi-modal Resonant Gravitational Wave Detector
Florian Dubath,Jerome Extermann,Luciano Gottardi
Physics , 2006, DOI: 10.1088/0264-9381/24/9/006
Abstract: We present a numerical analysis to simulate the response of a spherical resonant gravitational wave detector and to compute its sensitivity. Under the assump- tion of optimal filtering, we work out the sensitivity curve for a sphere first taking into account only a single transducer, and then using a coherent analysis of the whole set of transducers.
Forecasting Gas Reservoir Behavior with Identified Models Prévision du comportement des réservoirs de gaz à l'aide de modèles identifiés
Chierici G. L.,Gottardi G. A.,Guidorzi R. P.
Oil & Gas Science and Technology , 2006, DOI: 10.2516/ogst:1986037
Abstract: Gas reservoirs, like many other physical processes, belong to the large class of dynamic systems whose inputs and outputs are linked by dynamic rather than algebric relations, i. e. they are linked by differential or finite difference equations which take into account the system's memory. The prediction of reservoir pressure on the basis of assumed production programmes therefore calls for the use of suitable dynamic models. Those traditionally used in reservoir engineering are based on volumetric balance equations and on equations that take into account water encroachement from the underlying aquifer. These models are intrinsically realistic since they start from a description of the physical nature of the phenomenon involved. However, for their construction it is necessary to know various parameters characterizing the gas reservoir and the aquifer, and these parameters are not readily obtainable. A different approach to obtaining the models without resorting to a trial-and-error procedure is to use identification methods. This system theory technique enables a dynamic model to be identified based solely on input-output sequences of the process. This article describes the application of these techniques to two gas reservoirs, the problems encountered in such applications and the typical results that can be achieved. Comme beaucoup d'autres systèmes physiques, les réservoirs de gaz appartiennent à la grande classe des systèmes dynamiques dont les entrées et sorties sont reliées par des relations dynamiques plut t qu'algébriques, c'est-à-dire qu'elles sont reliées par des équations différentielles ou aux différences finies, qui tiennent compte de la mémoire du système. Par conséquent, la prévision de la pression du réservoir en fonction de scénarios de programmes de production donnés requiert l'emploi de modèles dynamiques appropriés. Les modèles utilisés traditionnellement dans les études de réservoir sont basés sur les équations d'équilibre volumétrique et sur des équations qui tiennent compte de l'envahissement par l'eau provenant de l'aquifère sous-jacent. Ces modèles sont, par principe, conformes à la réalité puisqu'ils partent de la description de la nature physique du phénomène en cause. Toutefois, pour les construire il faut conna tre différents paramètres qui caractérisent le réservoir de gaz et l'aquifère. Or, ces paramètres ne peuvent être aisement obtenus. Une approche différente pour établir des modèles sans recourir à la méthode des approximations successives est d'utiliser des méthodes d'identification. Cette technique, qui rentre dans la
Antimicrobial Potential and Chemical Characterization of Serbian Liverwort (Porella arboris-vitae): SEM and TEM Observations
Amit Kumar Tyagi,Danka Bukvicki,Davide Gottardi,Milan Veljic
Evidence-Based Complementary and Alternative Medicine , 2013, DOI: 10.1155/2013/382927
β-Catenin Phosphorylated at Serine 45 Is Spatially Uncoupled from β-Catenin Phosphorylated in the GSK3 Domain: Implications for Signaling
Meghan T. Maher,Rigen Mo,Annette S. Flozak,Ofra N. Peled,Cara J. Gottardi
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0010184
Abstract: C. elegans and Drosophila generate distinct signaling and adhesive forms of β-catenin at the level of gene expression. Whether vertebrates, which rely on a single β-catenin gene, generate unique adhesive and signaling forms at the level of protein modification remains unresolved. We show that β-catenin unphosphorylated at serine 37 (S37) and threonine 41 (T41), commonly referred to as transcriptionally Active β-Catenin (ABC), is a minor nuclear-enriched monomeric form of β-catenin in SW480 cells, which express low levels of E-cadherin. Despite earlier indications, the superior signaling activity of ABC is not due to reduced cadherin binding, as ABC is readily incorporated into cadherin contacts in E-cadherin-restored cells. β-catenin phosphorylated at serine 45 (S45) or threonine 41 (T41) (T41/S45) or along the GSK3 regulatory cassette S33, S37 or T41 (S33/37/T41), however, is largely unable to associate with cadherins. β-catenin phosphorylated at T41/S45 and unphosphorylated at S37 and T41 is predominantly nuclear, while β-catenin phosphorylated at S33/37/T41 is mostly cytoplasmic, suggesting that β-catenin hypophosphorylated at S37 and T41 may be more active in transcription due to its enhanced nuclear accumulation. Evidence that phosphorylation at T41/S45 can be spatially separated from phosphorylations at S33/37/T41 suggests that these phosphorylations may not always be coupled, raising the possibility that phosphorylation at S45 serves a distinct nuclear function.
CXCL12 and [N33A]CXCL12 in 5637 and HeLa Cells: Regulating HER1 Phosphorylation via Calmodulin/Calcineurin
Antonella Rigo, Michele Gottardi, Ernesto Damiani, Massimiliano Bonifacio, Isacco Ferrarini, Pierluigi Mauri, Fabrizio Vinante
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0034432
Abstract: In the human neoplastic cell lines 5637 and HeLa, recombinant CXCL12 elicited, as expected, downstream signals via both G-protein-dependent and β-arrestin-dependent pathways responsible for inducing a rapid and a late wave, respectively, of ERK1/2 phosphorylation. In contrast, the structural variant [N33A]CXCL12 triggered no β-arrestin-dependent phosphorylation of ERK1/2, and signaled via G protein-dependent pathways alone. Both CXCL12 and [N33A]CXCL12, however, generated signals that transinhibited HER1 phosphorylation via intracellular pathways. 1) Prestimulation of CXCR4/HER1-positive 5637 or HeLa cells with CXCL12 modified the HB-EGF-dependent activation of HER1 by delaying the peak phosphorylation of tyrosine 1068 or 1173. 2) Prestimulation with the synthetic variant [N33A]CXCL12, while preserving CXCR4-related chemotaxis and CXCR4 internalization, abolished HER1 phosphorylation. 3) In cells knockdown of β-arrestin 2, CXCL12 induced a full inhibition of HER1 like [N33A]CXCL12 in non-silenced cells. 4) HER1 phosphorylation was restored as usual by inhibiting PCK, calmodulin or calcineurin, whereas the inhibition of CaMKII had no discernable effect. We conclude that both recombinant CXCL12 and its structural variant [N33A]CXCL12 may transinhibit HER1 via G-proteins/calmodulin/calcineurin, but [N33A]CXCL12 does not activate β-arrestin-dependent ERK1/2 phosphorylation and retains a stronger inhibitory effect. Therefore, we demonstrated that CXCL12 may influence the magnitude and the persistence of signaling downstream of HER1 in turn involved in the proliferative potential of numerous epithelial cancer. In addition, we recognized that [N33A]CXCL12 activates preferentially G-protein-dependent pathways and is an inhibitor of HER1.
Nitrate transport in cucumber leaves is an inducible process involving an increase in plasma membrane H+-ATPase activity and abundance
Miroslav Nikolic, Stefano Cesco, Rossella Monte, Nicola Tomasi, Stefano Gottardi, Anita Zamboni, Roberto Pinton, Zeno Varanini
BMC Plant Biology , 2012, DOI: 10.1186/1471-2229-12-66
Abstract: The mechanism of nitrate uptake in leaves of cucumber (Cucumis sativus L. cv. Chinese long) plants was studied and compared with that of the root. Net nitrate uptake by roots of nitrate-depleted cucumber plants proved to be substrate-inducible and biphasic showing a saturable kinetics with a clear linear non saturable component at an anion concentration higher than 2?mM. Nitrate uptake by leaf discs of cucumber plants showed some similarities with that operating in the roots (e.g. electrogenic H+ dependence via involvement of proton pump, a certain degree of induction). However, it did not exhibit typical biphasic kinetics and was characterized by a higher Km with values out of the range usually recorded in roots of several different plant species. The quantity and activity of plasma membrane (PM) H+-ATPase of the vesicles isolated from leaf tissues of nitrate-treated plants for 12?h (peak of nitrate foliar uptake rate) increased with respect to that observed in the vesicles isolated from N-deprived control plants, thus suggesting an involvement of this enzyme in the leaf nitrate uptake process similar to that described in roots. Molecular analyses suggest the involvement of a specific isoform of PM?H+-ATPase (CsHA1) and NRT2 transporter (CsNRT2) in root nitrate uptake. At the leaf level, nitrate treatment modulated the expression of CsHA2, highlighting a main putative role of this isogene in the process.Obtained results provide for the first time evidence that a saturable and substrate-inducible nitrate uptake mechanism operates in cucumber leaves. Its activity appears to be related to that of PM?H+-ATPase activity and in particular to the induction of CsHA2 isoform. However the question about the molecular entity responsible for the transport of nitrate into leaf cells therefore still remains unresolved.The availability of nitrate strongly affects both crop productivity and food quality. In fact, in agricultural well-aerated soils, this anion is the main source of
Identification of Volatile Components of Liverwort (Porella cordaeana) Extracts Using GC/MS-SPME and Their Antimicrobial Activity
Danka Bukvicki,Davide Gottardi,Milan Veljic,Petar D. Marin,Lucia Vannini,Maria Elisabetta Guerzoni
Molecules , 2012, DOI: 10.3390/molecules17066982
Abstract: Chemical constituents of liverwort (Porella cordaeana) extracts have been identified using solid-phase microextraction-gas chromatography mass spectrometry (SPME-GC/MS). The methanol, ethanol and ethyl acetate extracts were rich in terpenoids such as sesquiterpene hydrocarbons (53.12%, 51.68%, 23.16%), and monoterpene hydrocarbons (22.83%, 18.90%, 23.36%), respectively. The dominant compounds in the extracts were β-phellandrene (15.54%, 13.66%, 12.10%) and β-caryophyllene (10.72%, 8.29%, 7.79%, respectively). The antimicrobial activity of the extracts was evaluated against eleven food microorganisms using the microdilution and disc diffusion methods. The minimum inhibitory concentration (MIC) varied from 0.50 to 2.00 mg/mL for yeast strains (Saccharomyces cerevisiae 635, Zygosacharomyces bailii 45, Aerobasidium pullulans L6F, Pichia membranaefaciens OC 71, Pichia membranaefaciens OC 70, Pichia anomala CBS 5759, Pichia anomala DBVPG 3003 and Yarrowia lipolytica RO13), and from 1.00 to 3.00 mg/mL for bacterial strains (Salmonella enteritidis 155, Escherichia coli 555 and Listeria monocytogenes 56Ly). Methanol extract showed better activity in comparison with ethanol and ethyl acetate extracts. High percentages of monoterpene and sesquiterpene hydrocarbons could be responsible for the better antimicrobial activity.
Transjugular intravascular ultrasound for the evaluation of hepatic vasculature and parenchyma in patients with chronic liver disease
Andrea De Gottardi, Pierre-Frédéric Keller, Antoine Hadengue, Emile Giostra, Laurent Spahr
BMC Research Notes , 2012, DOI: 10.1186/1756-0500-5-77
Abstract: We tested the safety and performance of an intracardiac echography (ICE) catheter applied by a transjugular approach into the hepatic veins in patients with chronic liver disease undergoing hepatic hemodynamic measurements.Five patients were enrolled in this pilot study. The insertion of the ICE catheter was possible into the right and middle, but not into the left hepatic vein. The position of the ICE was followed using fluoroscopy and external conventional ultrasound. Accurate imaging of focal hepatic parenchymal lesions, Doppler ultrasound of surrounding blood vessels and assessment of liver surface and ascites were achieved without complications.This study demonstrated that a diagnostic approach using an ICE device inserted in the hepatic veins is feasible, safe and well tolerated. However, it remains for the moment only an experimental investigative tool. Whether ICE adds further information regarding parenchymal lesions and associated vascular alterations as compared to other techniques, needs additional investigation.Assessment of disease extent is an important process in the management of patients with chronic liver disease and suspected parenchymal or vascular lesions [1-3]. The spatial relationship between lesions and their surrounding anatomical structures - portal vein branches, hepatic veins, bile ducts and liver capsule - is of particular importance for prognosis and choice of treatment.For instance in hepatocellular carcinoma (HCC), the size and the number of lesions represent the most critical information, impacting therapeutic options, that include surgical or radiofrequency ablation, transarterial chemoembolization, or liver transplantation. Patients with a single HCC nodule can be treated by surgical resection provided that this procedure is technically feasible, that the Child-Pugh stage is A, that the serum total bilirubin level is normal, that there is no vascular invasion and that the hepatic venous pressure gradient (HVPG) is 10 mmHg or less
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