13,532 research outputs found
Prenatal Rights Outside the Context of Abortion in Latin America and the Caribbean: A Comparative Analysis of Domestic Laws and Relevant Jurisprudence Following the Adoption of the American Convention on Human Rights
Quantitative Analysis of the Effective Functional Structure in Yeast Glycolysis
Yeast glycolysis is considered the prototype of dissipative biochemical
oscillators. In cellular conditions, under sinusoidal source of glucose, the
activity of glycolytic enzymes can display either periodic, quasiperiodic or
chaotic behavior.
In order to quantify the functional connectivity for the glycolytic enzymes
in dissipative conditions we have analyzed different catalytic patterns using
the non-linear statistical tool of Transfer Entropy. The data were obtained by
means of a yeast glycolytic model formed by three delay differential equations
where the enzymatic speed functions of the irreversible stages have been
explicitly considered. These enzymatic activity functions were previously
modeled and tested experimentally by other different groups. In agreement with
experimental conditions, the studied time series corresponded to a
quasi-periodic route to chaos. The results of the analysis are three-fold:
first, in addition to the classical topological structure characterized by the
specific location of enzymes, substrates, products and feedback regulatory
metabolites, an effective functional structure emerges in the modeled
glycolytic system, which is dynamical and characterized by notable variations
of the functional interactions. Second, the dynamical structure exhibits a
metabolic invariant which constrains the functional attributes of the enzymes.
Finally, in accordance with the classical biochemical studies, our numerical
analysis reveals in a quantitative manner that the enzyme phosphofructokinase
is the key-core of the metabolic system, behaving for all conditions as the
main source of the effective causal flows in yeast glycolysis.Comment: Biologically improve
Identification of redundant and synergetic circuits in triplets of electrophysiological data
Neural systems are comprised of interacting units, and relevant information
regarding their function or malfunction can be inferred by analyzing the
statistical dependencies between the activity of each unit. Whilst correlations
and mutual information are commonly used to characterize these dependencies,
our objective here is to extend interactions to triplets of variables to better
detect and characterize dynamic information transfer. Our approach relies on
the measure of interaction information (II). The sign of II provides
information as to the extent to which the interaction of variables in triplets
is redundant (R) or synergetic (S). Here, based on this approach, we calculated
the R and S status for triplets of electrophysiological data recorded from
drug-resistant patients with mesial temporal lobe epilepsy in order to study
the spatial organization and dynamics of R and S close to the epileptogenic
zone (the area responsible for seizure propagation). In terms of spatial
organization, our results show that R matched the epileptogenic zone while S
was distributed more in the surrounding area. In relation to dynamics, R made
the largest contribution to high frequency bands (14-100Hz), whilst S was
expressed more strongly at lower frequencies (1-7Hz). Thus, applying
interaction information to such clinical data reveals new aspects of
epileptogenic structure in terms of the nature (redundancy vs. synergy) and
dynamics (fast vs. slow rhythms) of the interactions. We expect this
methodology, robust and simple, can reveal new aspects beyond pair-interactions
in networks of interacting units in other setups with multi-recording data sets
(and thus, not necessarily in epilepsy, the pathology we have approached here).Comment: 31 pages, 6 figures, 3 supplementary figures. To appear in the
Journal of Neural Engineering in its current for
Seed beetles (Coleoptera: Bruchidae) associated with Acacia cornigera (L.) Willd., with description of a new species of Acanthoscelides Schilsky
Presented herein is a key to identify species of Bruchidae associated with Acacia cornigera (L.). For each species, host records, distributions and bionomics are given. A new species of Acanthoscelides Schilsky is described and figured; Acanthoscelides sauli Romero, Cruz, and Kingsolver
Vibrations on pulse tube based Dry Dilution Refrigerators for low noise measurements
Dry Dilution Refrigerators (DDR) based on pulse tube cryo-coolers have
started to replace Wet Dilution Refrigerators (WDR) due to the ease and low
cost of operation. However these advantages come at the cost of increased
vibrations, induced by the pulse tube. In this work, we present the vibration
measurements performed on three different commercial DDRs. We describe in
detail the vibration measurement system we assembled, based on commercial
accelerometers, conditioner and DAQ, and examined the effects of the various
damping solutions utilized on three different DDRs, both in the low and high
frequency regions. Finally, we ran low temperature, pseudo-massive (30 and 250
g) germanium bolometers in the best vibration-performing system under study and
report on the results
Revisiting Baby Boy v. United States: Why the IACHR Resolution did not Effectively Undermine the Inter-American System on Human Rights\u27 Protection of the Right to Life from Conception
Time-Reversal Violating Schiff Moment of 225Ra
We use the Skyrme-Hartree-Fock method, allowing all symmetries to be broken,
to calculate the time-reversal-violating nuclear Schiff moment (which induces
atomic electric dipole moments) in the octupole-deformed nucleus 225Ra. Our
calculation includes several effects neglected in earlier work, including self
consistency and polarization of the core by the last nucleon. We confirm that
the Schiff moment is large compared to those of reflection-symmetric nuclei,
though ours is generally a few times smaller than recent estimates.Comment: Typos corrected, references added, minor changesin text. Version to
appear in PRC. 10 pages, 4 figure
- …