1,671 research outputs found
Moral and Philosophic Problems of Modern Medicine: A Collegiate Program for Pre-Medical and Nursing Students
Equilibration of quantum Hall edge states by an Ohmic contact
Ohmic contacts are crucial elements of electron optics that have not received
a clear theoretical description yet. We propose a model of an Ohmic contact as
a piece of metal of the finite capacitance attached to a quantum Hall edge.
It is shown that charged quantum Hall edge states may have weak coupling to
neutral excitations in an Ohmic contact. Consequently, despite being a
reservoir of neutral excitations, an Ohmic contact is not able to efficiently
equilibrate edge states if its temperature is smaller than ,
where is the inverse RC time of the contact. This energy scale for a
floating contact may become as large as the single-electron charging energy
.Comment: 5 pages, 4 figures; revised versio
Relation between the High Density Phase and the Very-High Density Phase of Amorphous Solid Water
It has been suggested that high-density amorphous (HDA) ice is a structurally
arrested form of high-density liquid (HDL) water, while low-density amorphous
(LDA) ice is a structurally arrested form of low-density liquid (LDL) water.
Recent experiments and simulations have been interpreted to support the
possibility of a second "distinct" high-density structural state, named very
high-density amorphous (VHDA) ice, questioning the LDL-HDL hypothesis. We test
this interpretation using extensive computer simulations, and find that VHDA is
a more stable form of HDA and that in fact VHDA should be considered as the
amorphous ice of the quenched HDL.Comment: 5 pages, 4 fig
Structural Order in Glassy Water
We investigate structural order in glassy water by performing classical
molecular dynamics simulations using the extended simple point charge (SPC/E)
model of water. We perform isochoric cooling simulations across the glass
transition temperature at different cooling rates and densities. We quantify
structural order by orientational and translational order metrics. Upon cooling
the liquid into the glassy state, both the orientational order parameter
and translational order parameter increase. At T=0 K, the glasses fall
on a line in the - plane or {\it order map}.
The position of this line depends only on density and coincides with the
location in the order map of the inherent structures (IS) sampled upon cooling.
We evaluate the energy of the IS, , and find that both order
parameters for the IS are proportional to . We also study the
structural order during the transformation of low-density amorphous ice (LDA)
to high-density amorphous ice (HDA) upon isothermal compression and are able to
identify distinct regions in the order map corresponding to these glasses.
Comparison of the order parameters for LDA and HDA with those obtained upon
isochoric cooling indicates major structural differences between glasses
obtained by cooling and glasses obtained by compression. These structural
differences are only weakly reflected in the pair correlation function. We also
characterize the evolution of structural order upon isobaric annealing, leading
at high pressure to very-high density amorphous ice (VHDA).Comment: submitte
Isolation and identification of Candida albicans to produce in house helicase for PCR
Candida albicans is a dimorphic fungus that can grow in a wide range of temperature. In such case, this microorganism has the potential to produce enzymes that able to function at elevated temperature. These enzymes are also essential in the field of molecular biology and recombinant technologies. Therefore, the enzymes produced by Candida albicans could be applied in the polymerase chain reaction (PCR). The PCR is the most widely used in DNA amplification. In this study, Candida spp. were successfully isolated and collected from Hospital Universiti Sains Malaysia, Kubang Kerian, Kelantan, Malaysia. Different culture media were used to identify the morphology of colony. Based on the colonies growth on chromogenic agar, Candida sp. was identified. Microscopic examination (light and scanning microscopy) was carried out to identify the morphology of the isolate. A presumptive identification of germ tube test was performed to find out the dimorphic and pathogenicity characteristic of isolate. The formation of germ tubes from the isolate showed positive result of Candida albicans. A commercial Analytical Profile Index (API) Candida identification kit was used in this study as a phenotypic identification of Candida sp. The result of API Candida was confirmed that the isolate was the Candida albicans. Candida albicans was successfully isolated and identified phenotypically in this study for future in house helicase production
Connecting geodesics and security of configurations in compact locally symmetric spaces
A pair of points in a riemannian manifold makes a secure configuration if the
totality of geodesics connecting them can be blocked by a finite set. The
manifold is secure if every configuration is secure. We investigate the
security of compact, locally symmetric spaces.Comment: 27 pages, 2 figure
Interplay Between Time-Temperature-Transformation and the Liquid-Liquid Phase Transition in Water
We study the TIP5P water model proposed by Mahoney and Jorgensen, which is
closer to real water than previously-proposed classical pairwise additive
potentials. We simulate the model in a wide range of deeply supercooled states
and find (i) the existence of a non-monotonic ``nose-shaped'' temperature of
maximum density line and a non-reentrant spinodal, (ii) the presence of a low
temperature phase transition, (iii) the free evolution of bulk water to ice,
and (iv) the time-temperature-transformation curves at different densities.Comment: RevTeX4, 4 pages, 4 eps figure
Percolation Threshold, Fisher Exponent, and Shortest Path Exponent for 4 and 5 Dimensions
We develop a method of constructing percolation clusters that allows us to
build very large clusters using very little computer memory by limiting the
maximum number of sites for which we maintain state information to a number of
the order of the number of sites in the largest chemical shell of the cluster
being created. The memory required to grow a cluster of mass s is of the order
of bytes where ranges from 0.4 for 2-dimensional lattices
to 0.5 for 6- (or higher)-dimensional lattices. We use this method to estimate
, the exponent relating the minimum path to the
Euclidean distance r, for 4D and 5D hypercubic lattices. Analyzing both site
and bond percolation, we find (4D) and
(5D). In order to determine
to high precision, and without bias, it was necessary to
first find precise values for the percolation threshold, :
(4D) and (5D) for site and
(4D) and (5D) for bond
percolation. We also calculate the Fisher exponent, , determined in the
course of calculating the values of : (4D) and
(5D)
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