7,996 research outputs found
Digistylus - An Online Information System For Palaeography Teaching and Research
This paper starts by describing the experiences the authors recently had with online information systems for teaching and research in palaeography. The study also considers the differences in the students' access to the site "Teaching Materials for Latin Palaeography" when they attended the palaeography courses, as it was usually used in the lectures by one of the authors. With the increase in the quantity of plates (reproducing pages or parts of them from medieval manuscripts) and texts (concerning the analysis of the writing styles, the cataloguing, the history of manuscripts, the codicology and other important topics in the palaeography's scientific debate), it became clear that there was a difference in the way students approached those materials: when students first used the systems in the academic year 2001/2002, they read all the documents and used all the plates; more recently, with the quantity of materials on the site considerably increased, the students wait for the professor's suggestions and evidence uncertainties and difficulties when autonomously looking for a document or a plate. As a consequence, the online information system Digistylus has been planned and is going to be created for the management of the data in the site "Teaching Materials". The main consequence of the above observations has been the detection of a new knowledge construction paradigm and the development of new research procedures in palaeography
Monte Carlo determination of the critical coupling in theory
We use lattice formulation of theory in order to investigate
non--perturbative features of its continuum limit in two dimensions. In
particular, by means of Monte Carlo calculations, we obtain the critical
coupling constant in the continuum, where is the {\em
unrenormalised} coupling. Our final result is .Comment: Version published on Phys. Rev. D. We added a reference and modified
a couple of sentence
Measuring Demand Factors Influencing Market Penetration and Buying Frequency for Flowers in the U.S.
floriculture, consumer preferences, ornamentals, horticulture, environmental, Consumer/Household Economics, Demand and Price Analysis,
Fibrinogen-binding proteins from Staphylococcus aureus
Staphylococcus aureus produces a large number of proteins that specifically bind to molecules from plasma or from the human extracellular matrix where they are involved in processes associated with the colonization of the host tissues. At least six different fibrinogen-binding proteins have been identified from S. aureus; Clumping factor A and B (ClfA and ClfB), Coagulase, Efb (previously Fib), FbpA , Map and Eap. This work focuses primarily on the function(s) of Efb and Eap.
We have shown that Efb contributes to the virulence of S. aureus in wound infection. An allele replacement mutant of Efb was constructed and compared with the virulence of the wild type in a rat model of wound infection. Sixty-seven % of the animals challenged with the parental strain developed severe clinical signs of wound infection, whereas only 29% of the rats infected with the isogenic mutant showed severe symptoms. The function of Efb in infection is unclear but we have shown in vitro that multiple binding sites are involved in the interaction between Efb and fibrinogen. One binding site is located at the C terminus of Efb and one binding site at the two repeat regions of the N terminus. These N-terminal repeats are homologous to those at the C terminus of coagulase. The divalent binding nature of Efb with Fg leads to the precipitation of the Efb-fibrinogen complex, which can be enhanced by Ca or Zn but not by Mg. At least one of the binding sites for Efb is located at the Aα-chain of Fg (Aα 111 - Aα 197). Binding of Efb to this site may serve to block specific Aα-chain processes. In addition, we have shown that Efb could bind to fibrin as well as to fibrinogen and that the two repeats of Efb could compete with the five repeats of coagulase for the same binding domain on fibrinogen.
We have shown in this study that Eap (extracellular adherence protein) have the ability to enhance the adherence of Staphylococcus aureus to host cells. Eap can bind at least seven plasma proteins, including fibrinogen, prothrombin and fibronectin. Eap is presumably the same, or at least related to a previously described cell surface protein, designated Map for major histocompatibility complex class II analogous protein. In contrast to Map, Eap is mainly extracellular since 70% of the protein was found in the culture supernatant of S. aureus strain Newman. In this study we proposed a novel mechanism for adherence of S. aureus to host components stimulated and mediated by Eap. This is based on the fact that; i) Eap can form olimeric forms ii) Staphylococcus aureus strain Newman adhere to immobilized and soluble Eap, but not to the other staphylococcal proteins tested iii) Eap was able to cause agglutination of Staphylococcus aureus and iv) Attachment of S. aureus to fibroblasts and epithelial cells was significantly enhanced by the presence of Eap.
In conclusion, Staphylococcus aureus produce several fibrinogen-binding proteins that interact with fibrinogen in different ways. Colonization of the host tissues and dissemination of the infection is a multifactorial event in which many extracellular and cellsurface proteins are involved. FgBPs play an important role during infection by: a) A cellsurface FgBP that mediates the direct attachment of S. aureus to damaged heart valves and implanted biomaterial, b) A secreted FgBP with broad binding specificity that promotes colonisation of host tissues and bacterial aggregation, and c) A 15.9 kDa secreted FgBP that influences the severity of a wound infected by S. aureus thereby altering the healing process
Study on fouling behaviour of ultrafiltration and nanofiltration during purification of different organic matter polluted wastewaters
The boundary flux concept is a profitable tool to analyse fouling issues in membrane processes. The boundary flux value separates an operating region characterized by reversible fouling formation from irreversible one. Boundary flux values are not constant, but function of time, as calculated by the sub-boundary fouling rate value. The knowledge of both parameters may fully describe the membrane performances in sub-boundary operating regimes. Many times, for wastewater purification purposes, ultrafiltration and nanofiltration membranes are employed to treat different wastewater streams. This appears to be feasible from both technical and economical point of view many times. Whereas initial productivity and selectivity to reach the desired purification targets are generally guaranteed, key to reach process feasibility is that the membrane must resist to fouling issues, with a limited reduction of the performances as a function of time. In other words, longevity of the membranes must be that high to minimise their substitution and, consequently, operating (consumable) costs for the replacement. In this work, after a brief introduction to the boundary flux concept, for many different wastewater, the boundary flux and sub-boundary fouling rate values of different microfiltration and ultrafiltration membranes will be discussed and compared. By this approach, it will be possible to separate those systems where the use membranes for their treatment results successfully from those that represent a challenge (from a technical and/or economic point of view). This will depend sensibly of the feedstock characteristics and, in detail, on the particle size of the suspended matter and guidelines for process designers will be discussed. In most cases, it will be shown that membranes appear to perform very well, making this technology very interesting for many case studies
Production of nano zero valent iron particles by means of a spinning disk reactor
Nitrates are considered hazard compounds for human health due to their tendency to be reduced to nitrites, in particular in reducing environment. Nano zero valent iron (nZVI) represents an efficient and low-cost adsorbent/reductive agent for nitrate removal from groundwater. In this work, nZVI particles were produced by means of two different equipment types based on the same chemical synthesis method: a batch stirred tank reactor (BSTR) and a spinning disk reactor (SDR). This latter apparatus is capable to strongly promote micromixing at a steady-state, continuous condition, and such as qualifies to subsist in the framework of process intensification. Particle size distribution (PSD) of the obtained nZVI particles were measured by a DLS technique. The removal efficiency of the produced nVI particles were checked by using two NO3-solutions (1.6 and 6.4 mM) and by monitoring nitrate concentration reduction rates at selected time intervals. Results showed that the nZVI particles produced by SDR have a narrow PSD with a mean diameter of 65nm; on the contrary, particles produced by BSTR shows bimodal PSD with modal sizes of 105 nm and 400 nm, respectively. Experimental tests of nitrates reduction in water have been performed, using both the particles produced by the above mentioned techniques. Results of batch tests showed that the highest removal efficiency of nitrates was observed by using the nZVI particles produced by means of SDR, as a consequence of the higher average specific surface. Since nitrate removal process involves both reduction and adsorption processes, the removal mechanism has been investigated, and the pseudo-first-order reduction kinetic model was successfully tested and reported in both cases
From nature as source to nature as ethos: The making of natural man in Rousseau's Dialogues.
Challenging Jean Starobinski's critique of Rousseau juge de Jean-Jacques, Dialogues, this thesis locates arguments for the Rousseauian synthesis and its ideal of Natural Man in the philosophies of nature, habit and the will. Rousseau's concept of nature represents both a given, timeless inheritance or moral source, but also a unity which individuals actualise through reason and acts of the ethical will. The philosophy of habit suggested in Emile eliminates the concepts of denaturation and second nature invoked by commentators to clarify the relation between nature and habit. Authentic, permanent habits disclose nature; nature transcends itself through habit. A philosophy of the will, meanwhile, specifies the enlightened initiatives that fulfil the human telos, sponsoring the Form nature assumes through habit. The modalities of nature, habit and will thereby establish a continuity between the natural and ethical selves. Nature, habit and will also define the conditions of possibility for Natural Man exemplified by "Jean-Jacques". The Dialogues strive to remain intellectually coherent, but Rousseau's self-representation via an objective, third-person perspective proves rhetorically infelicitous for these conditions. The conflict of truth and method at the heart of autobiography abstracts the origins and history that mediate the synthesis that is Natural Man. Readers face a transcendental problem that must account for the points of transition needed for the synthesis to emerge. This account derives from an analysis of Rousseau's naturel, a spontaneity that, in fact, corresponds to a moral condition or ethos generated by sedimented acts of the ethical will. The thesis concludes that the Dialogues belong to and advance the Rousseau's 'system'. By internalising his own ethical construct, Rousseau and his works coincide. An ethical vision that reconciles goodness and virtue, nature and history demonstrates how Natural Man is possible
EVALUATING FACTORS INFLUENCING GROCERY STORE CHOICE
This paper analyzes consumer preferences toward grocery store choices given a set of attributes of stores. This information will then be used to make inferences on how the opening of a Wal-Mart supercenter would affect the other grocery stores in a small city.Consumer/Household Economics, Institutional and Behavioral Economics,
- …