2,679 research outputs found
What is a Gene? A Two Sided View
The need to account for all currently available experimental observations
concerning the gene nature, has reshaped the concept of gene turning it from the
essentially mechanistic unit, predominant during the '70s, into a quite abstract
open and generalized entity, whose contour appears less defined as compared to the
past. Here we propose the essence of the gene to be considered double faced. In
this respect genotypic and phenotypic entities of a gene would coexist and mix
reciprocally. This harmonizes present knowledge with current definitions and
predisposes for remodelling of our thinking as a consequence of future discoveries.
A two sided view of the gene also allows to combine the genetic and epigenetic
aspects in a unique solution, being structural and functional at the same time and
simultaneously able to include the different levels in an overlapping unicum
Is “Unconsummated Marriage” still an appropriate term? A snapshot of reality
The most shared definition of Unconsummated Marriage (UM) refers to “the failure to perform successful sexual intercourse at the beginning of
the marriage. UM usually occurs in the first few nights of marriage and so it is frequently referred to as “honeymoon impotence” or “wedding night
impotence”. In the Middle-Eastern (MES) and Western (WS) societies, sexuality follows different patterns in terms of meaning and rules. Moreover
the evolution of societies all around the world created new contexts and kinds of relationship. This could hamper a correct taxonomy of such sexual
dysfunction where a social variable seems crucial.
Aim: To analyze and review data on UM all around the world, to understand if in different societies it refers to the same situation.
Method: A review of published literature on UM from 1970 to date, was conducted.
Results: Substantial difference emerged from MES to WS. In MES, sexuality is allowable only in marriage, while in WS sexuality and relationship are
not strongly linked. This could suggest that the term “marriage” is unable to cover the phenomenon in such different countries. Moreover, the average
time before the consultation, causal attribution and prevalence are very different in Western and Middle Eastern countries.
Conclusion: We found that the term “first attempts dysfunction” could be better used to describe male, female or both difficulties related to
ignorance about sexuality or state/performance anxiety. On the other hand over the individual category of sexual dysfunctions, we suggest a new term
as “Unconsummated relationship”, where individual difficulties toward sexuality are involved creating a couple’s dysfunction.
Keywords: Unconsummated marriage; Honeymoon impotence; White marriage; Vaginismus; Infertilit
Exciton-phonon scattering and photo-excitation dynamics in J-aggregate microcavities
We have developed a model accounting for the photo-excitation dynamics and
the photoluminescence of strongly coupled J-aggregate microcavities. Our model
is based on a description of the J-aggregate film as a disordered Frenkel
exciton system in which relaxation occurs due to the presence of a thermal bath
of molecular vibrations. In a strongly coupled microcavity exciton-polaritons
are formed, mixing superradiant excitons and cavity photons. The calculation of
the microcavity steady-state photoluminescence, following a CW non resonant
pumping, is carried out. The experimental photoluminescence intensity ratio
between upper and lower polariton branches is accurately reproduced. In
particular both thermal activation of the photoluminescence intensity ratio and
its Rabi splitting dependence are a consequence of the bottleneck in the
relaxation, occurring at the bottom of the excitonic reservoir. The effects due
to radiative channels of decay of excitons and to the presence of a
paritticular set of discrete optical molecular vibrations active in relaxation
processes are investigared.Comment: 8 pages, 6 figure
Helical edge states in multiple topological mass domains
The two-dimensional topological insulating phase has been experimentally
discovered in HgTe quantum wells (QWs). The low-energy physics of
two-dimensional topological insulators (TIs) is described by the
Bernevig-Hughes-Zhang (BHZ) model, where the realization of a topological or a
normal insulating phase depends on the Dirac mass being negative or positive,
respectively. We solve the BHZ model for a mass domain configuration, analyzing
the effects on the edge modes of a finite Dirac mass in the normal insulating
region (soft-wall boundary condition). We show that at a boundary between a TI
and a normal insulator (NI), the Dirac point of the edge states appearing at
the interface strongly depends on the ratio between the Dirac masses in the two
regions. We also consider the case of multiple boundaries such as NI/TI/NI,
TI/NI/TI and NI/TI/NI/TI.Comment: 11 pages, 15 figure
Simulation of hydrogenated graphene Field-Effect Transistors through a multiscale approach
In this work, we present a performance analysis of Field Effect Transistors
based on recently fabricated 100% hydrogenated graphene (the so-called
graphane) and theoretically predicted semi-hydrogenated graphene (i.e.
graphone). The approach is based on accurate calculations of the energy bands
by means of GW approximation, subsequently fitted with a three-nearest neighbor
(3NN) sp3 tight-binding Hamiltonian, and finally used to compute ballistic
transport in transistors based on functionalized graphene. Due to the large
energy gap, the proposed devices have many of the advantages provided by
one-dimensional graphene nanoribbon FETs, such as large Ion and Ion/Ioff
ratios, reduced band-to-band tunneling, without the corresponding disadvantages
in terms of prohibitive lithography and patterning requirements for circuit
integration
Geological Criteria for Evaluating seismicity revisited: Forty Years of Paleoseismic Investigations and the Natural Record of Past Earthquakes
The identifi cation of individual past earthquakes and their characterization in
time and space, as well as in magnitude, can be approached in many different ways
with a large variety of methods and techniques, using a wide spectrum of objects and
features. We revise the stratigraphic and geomorphic evidence currently used in the
study of paleoseismicity, after more than three decades since the work by Allen (1975),
which was arguably the fi rst critical overview in the fi eld of earthquake geology. Natural
objects or geomarkers suitable for paleoseismic analyses are essentially preserved
in the sediments, and in a broader sense, in the geologic record. Therefore, the study
of these features requires the involvement of geoscientists, but very frequently it is a
multidisciplinary effort. The constructed environment and heritage, which typically
are the focus of archaeoseismology and macroseismology, here are left aside. The geomarkers
suitable to paleoseismic assessment can be grouped based on their physical
relation to the earthquake\u2019s causative fault. If directly associated with the fault surface
rupture, these objects are known as direct or on-fault features (primary effects
in the Environmental Seismic Intensity [ESI] 2007 scale). Conversely, those indicators
not in direct contact with the fault plane are known as indirect or off-fault evidence
(secondary effects in the ESI 2007 scale). This second class of evidence can be subdivided
into three types or subclasses: type A, which encompasses seismically induced
effects, including soft-sediment deformation (soil liquefaction, mud diapirism), mass
movements (including slumps), broken (disturbed) speleothems, fallen precarious
rocks, shattered basement rocks, and marks of degassing (pockmarks, mud volcanoes);
type B, which consists of remobilized and redeposited sediments (turbidites, homogenites, and tsunamites) and transported rock fragments (erratic blocks); and
type C, entailing regional markers of uplift or subsidence (such as reef tracts, microatolls,
terrace risers, river channels, and in some cases progressive unconformities).
The fi rst subclass of objects (type A) is generated by seismic shaking. The second
subclass (type B) relates either to water bodies set in motion by the earthquake (for
the sediments and erratic blocks) or to earthquake shaking; in a general way, they all
relate to wave propagation through different materials. The third subclass (type C) is
mostly related to the tectonic deformation itself and can range from local (next to the
causative fault) to regional scale.
The natural exposure of the paleoseismic objects\u2014which necessarily conditions
the paleoseismic approach employed\u2014is largely controlled by the geodynamic setting.
For instance, oceanic subduction zones are mostly submarine, while collisional
settings tend to occur in continental environments. Divergent and wrenching margins
may occur anywhere, in any marine, transitional, or continental environment.
Despite the fact that most past subduction earthquakes have to be assessed through
indirect evidence, paleoseismic analyses of this category of events have made dramatic
progress recently, owing to the increasingly catastrophic impact that they have
on human society
Helical edge states in multiple topological mass domains
The two-dimensional topological insulating phase has been experimentally
discovered in HgTe quantum wells (QWs). The low-energy physics of
two-dimensional topological insulators (TIs) is described by the
Bernevig-Hughes-Zhang (BHZ) model, where the realization of a topological or a
normal insulating phase depends on the Dirac mass being negative or positive,
respectively. We solve the BHZ model for a mass domain configuration, analyzing
the effects on the edge modes of a finite Dirac mass in the normal insulating
region (soft-wall boundary condition). We show that at a boundary between a TI
and a normal insulator (NI), the Dirac point of the edge states appearing at
the interface strongly depends on the ratio between the Dirac masses in the two
regions. We also consider the case of multiple boundaries such as NI/TI/NI,
TI/NI/TI and NI/TI/NI/TI.Comment: 11 pages, 15 figure
Induced sputum cellularity. Reference values and distribution in normal volunteers.
Abstract
Sputum induction has recently been proposed as the only direct noninvasive method for measuring airway inflammatory indices. The reference values and the distribution of cells in induced sputum in a control population have not yet been well defined. We therefore evaluated data from a large number of healthy volunteers. One hundred fourteen healthy, nonatopic, nonsmoking volunteers without airway hyperreactivity were enrolled (age: 38 +/- 13 yr [mean +/- SD]; FEV(1): 105 +/- 10% predicted; provocative dose of methacholine inducing a 20% decrease FEV(1) > 3,200 microgram). Ninety-six subjects (84%) produced adequate analysis samples. The subjects had a normal age distribution. Their induced sputum was rich in macrophages (69.2 +/- 13%) and neutrophils (27.3 +/- 13%), and poor in eosinophils (0.6 +/- 0.8%), lymphocytes (1.0 +/- 1.2%), and epithelial cells (1.5 +/- 1.8%). Only macrophages and neutrophils showed a normal distribution; total and differential counts of other cells did not. We propose that these data be used in comparison of the induced sputum cells of normal subjects and those of patients with airway inflammation
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