558 research outputs found
Тестування як засіб контролю студентів в дистанційних курсах
Some questions of electronic testing in distance learning are concerned in the article: its importance in checking students’ knowledge, the main spheres of tests usage, testing possibilities in the virtual educational environment "Web-Class-KPI", special moments in criteria testings
Fractally-organized Connectionist Networks: Conjectures and Preliminary Results
A strict interpretation of connectionism mandates complex networks of simple
components. The question here is, is this simplicity to be interpreted in
absolute terms? I conjecture that absolute simplicity might not be an essential
attribute of connectionism, and that it may be effectively exchanged with a
requirement for relative simplicity, namely simplicity with respect to the
current organizational level. In this paper I provide some elements to the
analysis of the above question. In particular I conjecture that fractally
organized connectionist networks may provide a convenient means to achive what
Leibniz calls an "art of complication", namely an effective way to encapsulate
complexity and practically extend the applicability of connectionism to domains
such as sociotechnical system modeling and design. Preliminary evidence to my
claim is brought by considering the design of the software architecture
designed for the telemonitoring service of Flemish project "Little Sister".Comment: Draft of an invited paper for PEWET (1st Workshop on PErvasive WEb
Technologies, trends and challenges),
http://www.irpps.cnr.it/en/events/call-for-papers-pewet-pervasive-web-technologies-trends-and-challenge
Intravenous infusions of glucose stimulate key lipogenic enzymes in adipose tissue of dairy cows in a dose-dependent manner
The present study was investigated whether increasing amounts of glucose
supply have a stimulatory effect on the mRNA abundance and activity of key
lipogenic enzymes in adipose tissue of midlactation dairy cows. Twelve
Holstein-Friesian dairy cows in midlactation were cannulated in the jugular
vein and infused with either a 40% glucose solution (n=6) or saline (n=6). For
glucose infusion cows, the infusion dose increased by 1.25%/d relative to the
initial net energy for lactation (NEL) requirement until a maximum dose
equating to a surplus of 30% NEL was reached on d 24. This maximum dose was
maintained until d 28 and stopped thereafter (between d 29-32). Cows in the
saline infusion group received an equivalent volume of 0.9% saline solution.
Samples of subcutaneous adipose tissue were taken on d 0, 8, 16, 24, and 32
when surplus glucose reached 0, 10, 20, and 30% of the NEL requirement,
respectively. The mRNA abundance of fatty acid synthase, cytoplasmic acetyl-
coenzyme A synthetase, cytoplasmic glycerol 3-phosphate dehydrogenase-1, and
glucose 6-phosphate dehydrogenase showed linear treatment × dose interactions
with increasing mRNA abundance with increasing glucose dose. The increased
mRNA abundance was paralleled by a linear treatment × dose interaction for
fatty acid synthase and acetyl-coenzyme A synthetase enzymatic activities. The
mRNA abundance of ATP-citrate lyase showed a tendency for linear treatment ×
dose interaction with increasing mRNA abundance with increasing glucose dose.
The mRNA abundance of all tested enzymes, as well as the activities of fatty
acid synthase and acetyl-coenzyme A synthetase, correlated with plasma glucose
and serum insulin levels. In a multiple regression model, the predictive value
of insulin was dominant over that of glucose. In conclusion, gradual increases
in glucose supply upregulate key lipogenic enzymes in adipose tissue of
midlactating dairy cows with linear dose dependency. Insulin appears to be
critically involved in this regulation. Copyright © 2013 American Dairy
Science Association. Published by Elsevier Inc. All rights reserved
Topology of energy surfaces and existence of transversal Poincar\'e sections
Two questions on the topology of compact energy surfaces of natural two
degrees of freedom Hamiltonian systems in a magnetic field are discussed. We
show that the topology of this 3-manifold (if it is not a unit tangent bundle)
is uniquely determined by the Euler characteristic of the accessible region in
configuration space. In this class of 3-manifolds for most cases there does not
exist a transverse and complete Poincar\'e section. We show that there are
topological obstacles for its existence such that only in the cases of
and such a Poincar\'e section can exist.Comment: 10 pages, LaTe
A voxelized immersed boundary (VIB) finite element method for accurate and efficient blood flow simulation
We present an efficient and accurate immersed boundary (IB) finite element
(FE) method for internal flow problems with complex geometries (e.g., blood
flow in the vascular system). In this study, we use a voxelized flow domain
(discretized with hexahedral and tetrahedral elements) instead of a box domain,
which is frequently used in IB methods. The proposed method utilizes the
well-established incremental pressure correction scheme (IPCS) FE solver, and
the boundary condition-enforced IB (BCE-IB) method to numerically solve the
transient, incompressible Navier--Stokes flow equations. We verify the accuracy
of our numerical method using the analytical solution for the Poiseuille flow
in a cylinder, and the available experimental data (laser Doppler velocimetry)
for the flow in a three-dimensional 90{\deg} angle tube bend. We further
examine the accuracy and applicability of the proposed method by considering
flow within complex geometries, such as blood flow in aneurysmal vessels and
the aorta, flow configurations that would otherwise be difficult to solve by
most IB methods. Our method offers high accuracy, as demonstrated by the
verification examples, and high applicability, as demonstrated through the
solution of blood flow within complex geometry. The proposed method is
efficient, since it is as fast as the traditional finite element method used to
solve the Navier--Stokes flow equations, with a small overhead (not more than
5) due to the numerical solution of a linear system formulated for the IB
method.Comment: arXiv admin note: substantial text overlap with arXiv:2007.0208
The H1 Forward Proton Spectrometer at HERA
The forward proton spectrometer is part of the H1 detector at the HERA
collider. Protons with energies above 500 GeV and polar angles below 1 mrad can
be detected by this spectrometer. The main detector components are
scintillating fiber detectors read out by position-sensitive photo-multipliers.
These detectors are housed in so-called Roman Pots which allow them to be moved
close to the circulating proton beam. Four Roman Pot stations are located at
distances between 60 m and 90 m from the interaction point.Comment: 20 pages, 10 figures, submitted to Nucl.Instr.and Method
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