8,125 research outputs found
The Possibility of an Afterlife as Examined Through Near-Death Experiences
Approximately five percent of the world’s population has dealt with a near-death experience, which is the unusual phenomenon after temporarily dying or coming close to death, where people feel like they have left their body and see an afterlife. Millions of accounts from people around the world who have experienced this occurrence tell of seeing an afterlife, which should allow for the possibility of a life after death. Although peoples’ experiences in another realm differ, they all have similar features such as travelling in a fast tunnel and encountering loving light beings. These experiences are so intense that they form a huge impact on their experiencer, thus people often change their actions and way of thinking after such an encounter with this other realm. Because many people alter their lives to such an extent following this experience, society should become more open and aware of the possibility that there could be a life after death. Although scientists have attempted to explain this phenomenon, there are still many unanswered questions
Aggregates of rod-coil diblock copolymers adsorbed at a surface
The behaviour of rod-coil diblock copolymers close to a surface is discussed
by using extended scaling methods. The copolymers are immersed in selective
solvent such that the rods are likely to aggregate to gain energy. The rods are
assumed to align only parallel to each other, such that they gain a maximum
energy by forming liquid crystalline structures. If an aggregate of these
copolymers adsorbs with the rods parallel to the surface the rods shift with
respect to each other to allow for the chains to gain entropy. It is shown that
this shift decays with increasing distance from the surface. The profile of
this decay away from the surface is calculated by minimisation of the total
free energy of the system. The stability of such an adsorbed aggregate and
other possible configurations are discussed as well.Comment: 10 pages, 11 figure
Entropy-induced Microphase Separation in Hard Diblock Copolymers
Whereas entropy can induce phase behavior that is as rich as seen in
energetic systems, microphase separation remains a very rare phenomenon in
entropic systems. In this paper, we present a density functional approach to
study the possibility of entropy-driven microphase separation in diblock
copolymers. Our model system consists of copolymers composed of freely-jointed
slender hard rods. The two types of monomeric segments have comparable lengths,
but a significantly different diameter, the latter difference providing the
driving force for the phase separation. At the same time these systems can also
exhibit liquid crystalline phases. We treat this system in the appropriate
generalization of the Onsager approximation to chain-like particles. Using a
linear stability (bifurcation) analysis, we analytically determine the onset of
the microseparated and the nematic phases for long chains. We find that for
very long chains the microseparated phase always preempts the nematic. In the
limit of infinitely long chains, the correlations within the chain become
Gaussian and the approach becomes exact. This allows us to define a Gaussian
limit in which the theory strongly simplifies and the competition between
microphase separation and liquid crystal formation can be studied essentially
analytically. Our main results are phase diagrams as a function of the
effective diameter difference, the segment composition and the length ratio of
the segments. We also determine the amplitude of the positional order as a
function of position along the chain at the onset of the microphase separation
instability. Finally, we give suggestions as to how this type of
entropy-induced microphase separation could be observed experimentally.Comment: 16 pages, 7 figure
Triple and quartic interactions of Higgs bosons in the two-Higgs-doublet model with CP violation
We consider the two-Higgs-doublet model with explicit CP-violation, where the
effective Higgs potential is not CP-invariant at the tree-level. Three neutral
Higgs bosons of the model are the mixtures of CP-even and CP-odd bosons which
exist in the CP-conserving limit of the theory. The mass spectrum and
tree-level couplings of the neutral Higgs bosons to gauge bosons and fermions
are significantly dependent on the parameters of the Higgs boson mixing matrix.
We calculate the Higgs-gauge boson, Higgs-fermion, triple and quartic Higgs
self-interactions in the MSSM with explicit CP-violation in the Higgs sector
and CP-violating Yukawa interactions of the third generation scalar quarks. In
some regions of the MSSM parameter space substantial changes of the
self-interaction vertices take place, leading to significant suppression or
enhancement of the multiple Higgs boson production cross sections.Comment: 29 pages, 4 figures. Minor changes in section 3, misprints in (47)
corrected. Version accepted by EPJ
Automatised full one-loop renormalisation of the MSSM I: The Higgs sector, the issue of tan(beta) and gauge invariance
We give an extensive description of the renormalisation of the Higgs sector
of the minimal supersymmetric model in SloopS. SloopS is an automatised code
for the computation of one-loop processes in the MSSM. In this paper, the first
in a series, we study in detail the non gauge invariance of some definitions of
tan(beta). We rely on a general non-linear gauge fixing constraint to make the
gauge parameter dependence of different schemes for tan(beta) at one-loop
explicit. In so doing, we update, within these general gauges, an important
Ward-Slavnov-Taylor identity on the mixing between the pseudo-scalar Higgs,
A^0, and the Z^0. We then compare the tan(beta) scheme dependence of a few
observables. We find that the best tan(beta) scheme is the one based on the
decay A^0 -> tau^+ tau^- because of its gauge invariance, being unambiguously
defined from a physical observable, and because it is numerically stable. The
oft used DRbar scheme performs almost as well on the last count, but is usually
defined from non-gauge invariant quantities in the Higgs sector. The use of the
heavier scalar Higgs mass in lieu of tan(beta) though related to a physical
parameter induces too large radiative corrections in many instances and is
therefore not recommended.Comment: 34 pages, 1 figure, typos corrected, accepted for publication in
Phys. Rev.
Preservation of equilibrium in orthograde and inverted body positions
The mechanism for regulation of the vertical pose with retention of equilibrium in the inverted body position was investigated
- …