1,193 research outputs found
Air Pollution and Mortality for 60 US Cities in 1960
No full textData includes measurements on mortality rate and explanatory variables(air-pollution, socio-economic and meteorological) for 60 US cities in 1960. This data was originally published in McDonald, G.C. and Schwing,R.C. (1973) 'Instabilities of regression estimates relating air pollution to mortality', Technometrics, vol.15, 463-482. It was redistributed through Carnegie Mellon University's StatLib (lib.stat.cmu.edu
Credit Card Security
Get PDFAuthor: Anup G.C.
Year: 2013
Subject of thesis: Credit Card Security
Number of pages: 36+2
Credit Card is a widely used electronic chip for easy transactions. The main purpose of the report was to show the security measures of transaction by credit cards. The purpose was to give information about credit cards and how they were introduced. The thesis reportcontained the types of card theft with examples and sited the various protocols used for online transactions. The aim of the thesis project was to conclude whether the card security provided by the banks is safe enough.
The thesis report contained information about many online resources as well as liable books. Many news articles were also considered while writing the report for the card theft records.
The thesis report described both the positive and negative aspects of the protocols used for card securities. Result showed that misuse and complicated processes of protocols has led the identity theft to transactions. To conclude, although many security measures are implemented for the secure transactions, credit card fraud activities are happening in a weekly basis
Preparation of karyoplasts and cytoplasts from feline oocytes at the germinal vesicle stage
No full textIntroduction. The homologous transfer of oocyte nucleus stage I or germinal vesicle (GV-karyoplast) into an enucleated mouse oocyte (cytoplast) at the same developmental stage, resulted in resumption of meiosis (1) and embryo development in vitro (2) of the reconstructed GV-oocytes. The transfer of GVs derived from cryopreserved oocytes also resulted in a normal progression to metaphase II (MII) in vitro of the reconstructed mouse and bovine oocytes (3,4). It has been shown that the GV is potentially more resilient to cooling than the spindle of MII, because chromosomes are decondensed and enclosed within the nuclear membrane. However, thawed immature cat oocytes show a poor developmental competence in vitro (5), probably due to the occurrence of chilling-induced damages to the cytoplasm. This compartment has a pivotal role in the resumption and completion of oocyte maturation, which is essential for the developmental competence of the embryo. Since the integrity of the oocyte nucleus may be better preserved than the cytoplasm after cryopreservation, the transfer of cryopreserved GVs into fresh enucleated oocytes could improve the chance of embryo development in culture. In the feline species there are no reports in the literature concerning GV transfer. Hence, the purpose of this work was to make a preliminary evaluation of the feasibility of enucleating immature oocytes in order to produce GV-karyoplasts and cytoplasts for GV transfer in cat oocytes.
Materials and methods. A total of 156 immature (GV) cat oocytes collected from anestrous queens after ovariectomy were mechanically deprived of cumulus cells with a small-bore pipette. The oocytes were centrifuged at 14000 rpm for 16 min to obtain the polarization of the cytoplasm and a better visualization of the GV. The nucleus was measured in order to prepare adequate microtools for manipulation. Prior to enucleation, the oocytes were incubated for 30 min at room temperature in a specific medium containing 7.5 g/mL of cytochalasin B (Sigma Chemical Co., USA) for inducing an increase of the oolemmal elasticity and 50 g/mL of 3-isobutyl-1-methylxanthine (IBMX, Sigma) in order to prevent the GV breakdown (1). Following lancing of the zona pellucida with a sharp-tipped pipette, GV nuclei were extruded using a bevelled glass pipette with a diameter adequate to the size of GV in cat oocytes. The GV was surrounded by a small amount of cytoplasm and encapsulated by a membrane (GV-karyoplast). The enucleated oocytes were considered as cytoplasts.
Results. The mean average of GV diameter in oocytes > 120 m of diameter was 35.4 + 5.3 m. A bevelled glass pipette, with inner diameter of 40-45 m, allowed the extrusion of intact and morphologically normal karyoplasts and related cytoplasts in 17.3% (27/156) of micromanipulated oocytes. However, the lancing of the zona pellucida or the extrusion of the karyoplast resulted in rates of 40.4% (63/156) and 42.3% (66/156) of severely damaged oocytes, respectively.
Conclusion. These results suggest that is possible to prepare karyoplasts and cytoplasts from feline oocytes, although the efficiency of the technique is low compared to what has been obtained in mouse (around 90%, 1). This is likely due to the thickness and hardness of zona pellucida, and to the larger diameter of the GV of cat oocytes compared to that of mouse (15 m) or bovine (25-30 m) oocytes. Further experiments based on the partial dissection of the zona pellucida with an acidic solution in order to reduce the oocyte damage and to improve the efficiency of GV transfer in feline oocytes, are in progress in our laboratory.
References
1) 1) Liu et al., Human Reprod 1999; 14:2357-61. 2) Takeuchi et al., Hum Reprod 2004;19:975–81.
3) Moffa et al., Human Reprod 2002;17:178-83. 4) Luciano et al., Reprod Fertil Dev 2006;18:138. 5) Luvoni and Pellizzari, Theriogenology 2000;53:1529-40
Electromagnetisch en vermoeiingsonderzoek aan gesloten ophaalkabels in mijnschachten
No full textMechanical, Maritime and Materials Engineerin
Pressure losses in pneumatic transport
No full textA model is derived to calculate the pressure losses originating from the dilute phase pneumatic transport of coarse particles in the horizontal stationary flow regime. The model is based on the balance of drag forces and frictional forces acting on the particles during pneumatic transport. The particles are characterized by the particle terminal velocity, the particle âwall sliding friction coefficient and the coefficient of restitution between particles and wall. The influence of the inhomogeneous particle distribution in the pipe is taken into account using a particle density distribution resembling the barometric height formula. The model is verified experimentally by the use of particle velocity measurements and particle-wall collision measurements during pneumatic transport. For this purpose measuring techniques and tools have been developed. A Froude number, based on the mean square value of the radial particle-velocity component, appears in the model as an empirical parameter. This Froude number increases with increasing average air velocity but may also depend on the pipe diameter and the solids-mass flow to some extent. However this dependency could not be quantified and may restrict the accuracy of pressure loss predictions with the model. The assumption of a linear relationship between the Froude number and the average air velocity provides scaling and prediction possibilities for pressure losses.Mechanical Maritime and Materials Engineerin
Removal of scattered surface waves from seismic data
No full textElectrical Engineering, Mathematics and Computer Scienc
Imaging and Suppressing Near-Receiver Scattered Seismic Waves
No full textCivil Engineering and Geoscience
Unsteady draining of a fluid from a circular tank
Get PDFThree-dimensional draining flow of a two-fluid system from a circular tank is considered. The two fluids are inviscid and incompressible, and are separated by a sharp interface. There is a circular hole positioned centrally in the bottom of the tank, so that the flow is axially symmetric. The mean position of the interface moves downwards as time progresses, and eventually a portion of the interface is withdrawn into the drain. For narrow drain holes of small radius, the interface above the centre of the drain is pulled down towards the hole. However, for drains of larger radius the portion of the interface above the drain edge is drawn down first, rather than the central section. Non-linear results are obtained with a novel spectral technique, and are also compared against the predictions of linearized theory. Unstable Rayleigh-Taylor type flows, in which the upper fluid is heavier than the lower one, are also discussed
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