349 research outputs found
Progress in Time-Dependent Density-Functional Theory
The classic density-functional theory (DFT) formalism introduced by
Hohenberg, Kohn, and Sham in the mid-1960s, is based upon the idea that the
complicated N-electron wavefunction can be replaced with the mathematically
simpler 1-electron charge density in electronic struc- ture calculations of the
ground stationary state. As such, ordinary DFT is neither able to treat
time-dependent (TD) problems nor describe excited electronic states. In 1984,
Runge and Gross proved a theorem making TD-DFT formally exact. Information
about electronic excited states may be obtained from this theory through the
linear response (LR) theory formalism. Begin- ning in the mid-1990s, LR-TD-DFT
became increasingly popular for calculating absorption and other spectra of
medium- and large-sized molecules. Its ease of use and relatively good accuracy
has now brought LR-TD-DFT to the forefront for this type of application. As the
number and the diversity of applications of TD-DFT has grown, so too has grown
our understanding of the strengths and weaknesses of the approximate
functionals commonly used for TD-DFT. The objective of this article is to
continue where a previous review of TD-DFT in this series [Annu. Rev. Phys.
Chem. 55: 427 (2004)] left off and highlight some of the problems and solutions
from the point of view of applied physical chemistry. Since doubly-excited
states have a particularly important role to play in bond dissociation and
formation in both thermal and photochemistry, particular emphasis will be
placed upon the problem of going beyond or around the TD-DFT adiabatic
approximation which limits TD-DFT calculations to nominally singly-excited
states. Posted with permission from the Annual Review of Physical Chemistry,
Volume 63 \c{opyright} 2012 by Annual Reviews, http://www.annualreviews.org
Effect of Enalapril on erythropoiesis recovery in murine anemia
La presencia de receptores de Angiotensina en células eritropoyéticas y estromales medulares muestra claramente
un mecanismo de regulación de la eritropoyesis mediado por el Sistema Renina-Angiotensina. El objetivo fue
estudiar los efectos de Inhibidores de la Enzima Convertidora de Angiotensina (IECA) como Enalapril (E) sobre
la respuesta eritropoyética en ratones anémicos tratados con Fenilhidrazina (FHZ), a través de estudios hematológicos
e histológicos. Tanto los ratones tratados con FHZ como los tratados con E y FHZ mostraron hemólisis el
día 14. Sin embargo, la recuperación del estado anémico fue el día 16 en ratones tratados con FHZ y el día 20 en
ratones tratados con E y FHZ. Se observó actividad eritropoyética en el bazo (día 16) y en el riñón (día 20) de
ratones tratados con E y FHZ. En ratones tratados con FHZ, se observó actividad eritropoyética en bazo y riñón
el día 16. Concluimos que la inhibición de la ECA con Enalapril retarda la recuperación eritropoyética en ratones
tratados con E y FHZ. La actividad eritropoyética en el bazo y riñón sugiere la participación de estos órganos en
la recuperación del eritrón.The presence of Angiotensin receptors in erythropoietic bone marrow and marrow stromal cells clearly shows a mechanism for
Rennin-Angiotensin System-mediated regulation of erythropoiesis. The aim was to study the effects of Angiotensin-Converting
Enzyme inhibition (ACEI) as Enalapril(E) on erythropoietic response in anemic mice treated with Phenylhydrazine (PHZ) by
means of hematological and histological studies. Both PHZ and E-PHZ-treated mice showed hemolysis on day 14. However
the restoration of anemic state occurred on day 16 in PHZ-treated mice and on day 20 in E-PHZ-treated mice. Erythropoietic
activity was observed in spleen (day16) and kidney (day20) of E-PHZ-treated mice. In PHZ-treated mice erythropoietic activity
was seen in spleen and kidney on day 16. We conclude that Inhibition of ACE with Enalapril delays the erythropoietic recovery
of hemolytic anemia in E-PHZ-treated mice. Erythropoietic activity in spleen and kidney suggest an involvement of these
organs in the erythron recovery.Este trabajo fue subsidiado por la Secretaría
General de Ciencia y Tecnología de la Universidad Nacional del Sur (Grant 24/B116) y por la Agencia de Promoción Científica y Tecnológica (FONCYT) (Grant-908). Tania Veuthey y María Cecilia D ́Anna son becarias doctorales del Consejo Nacional de Investigaciones Científicas y Técnica (CONICET)
When cooperation goes wrong : brain and behavioural correlates of ineffective joint strategies in dyads
Purpose: Human life is connoted by sophisticated interactions that involve not only single individuals, but larger social groups composed by members interacting each other. Cooperation secures a benefit to all the people engaged as well as important behaviors like helping, sharing, and acting prosocially. But what happens when the joint actions are not effective? Materials and method: In the present study, we asked 24 participants paired in 12 dyads to cooperate during an attentional task in a way to synchronize their responses and obtain better outcomes. In addition we tested inter-brain and cognitive strategy similarities between subjects. Then, we frustrated their strategies by providing false feedbacks signalling the incapacity to create a synergy, which was reinforced by a general negative evaluation halfway through the task. The effects of the feedback inmodulating subjects behavioural performance and brain responsiveness were explored by means of functional near-infrared spectroscopy (fNIRS). Results: Results showed a worsen performance after the negative feedback in the form of longer reaction times and a specifc pattern of brain activation involving th dorsolateral prefrontal cortex (DLPFC) and the superior frontal gyrus. The DLPFC showed increased O2Hb (oxy-haemoglobin) level after the feedback, compatible with the need for higher cognitive effort. In addition, fNIRS measures revealed a decreased inter-brain synchronicity in post-feedback condition for the dyad. Also, the representation of negative emotions in response to failing interactions was signalled by a right-lateralized effect. Conclusions: Results were interpreted at light of available knowledge on perceived self-efficacy and the implementation of common goals and strategies
Cooperate or not cooperate EEG, autonomic, and behavioral correlates of ineffective joint strategies
Introduction: The neural activity in response to ineffective joint actions was explored in the present study. Subjects involved in a cooperative but frustrating task (poor performance as manipulated by an external feedback) were required to cooperate (T1) during an attentional task in a way to synchronize their responses and obtain better outcomes. Methods: We manipulated their strategies by providing false feedbacks (T2) signaling the incapacity to create a synergy, which was reinforced by a general negative evaluation halfway through the game. A control condition was provided (no cooperation required, T0) as well as a check for possible learning effect (time series analysis). The effects of the feedback in modulating subjects' behavioral performance and electrocortical activity were explored by means of brain oscillations (delta, theta, alpha, beta) and autonomic activity (heart rate, HR; skin conductance activity, SCR). Results: Results showed a specific pattern of behavioral, neural, and peripheral responses after the social feedback. In fact, within this condition, worse behavioral outcomes emerged, with longer response times with respect to the prefeedback one. In parallel, a specific right-lateralized effect was observed over the dorsolateral prefrontal cortex (DLPFC), with increased delta and theta power compared to the previous condition. Moreover, increased SCR was observed with respect to the first part. Conclusions: Two interpretations are put forward to explain the present findings: 1) the contribution of negative emotions in response to failing interactions or 2) a motivational disengagement toward goal-oriented cooperation elicited by frustrating evaluations
Affective Synchrony and Autonomic Coupling during Cooperation : A Hyperscanning Study
Previous research highlighted that during social interactions people shape each other's emotional states by resonance mechanisms and synchronized autonomic patterns. Starting from the idea that joint actions create shared emotional experiences, in the present study a social bond was experimentally induced by making subjects cooperate with each other. Participants' autonomic system activity (electrodermal: Skin conductance level and response: SCL, SCR; cardiovascular indices: Heart rate: HR) was continuously monitored during an attentional couple game. The cooperative motivation was induced by presenting feedback which reinforced the positive outcomes of the intersubjective exchange. 24 participants coupled in 12 dyads were recruited. Intrasubject analyses revealed higher HR in the first part of the task, connoted by increased cognitive demand and arousing social dynamic, while intersubject analysis showed increased synchrony in electrodermal activity after the feedback. Such results encourage the use of hyperscanning techniques to assess emotional coupling in ecological and real-time paradigms
When brains dialogue by synchronized or unsynchronized languages : hyperscanning applications to neuromanagement
Neuromanagement deals with neuroscience methodological approaches to the management. A management construct is leadership, but objective psychophysiological data in support of it are still missing. The present pilot study aimed to apply the hyperscanning paradigm during a role-played employees' evaluation. Our purpose was to identify lexical and neuro/psychophysiological markers of leader-employee interactions. The sample consisted in paired manager-collaborator couples. Managers were required to use two different communication styles: authoritative vs. cooperative. A conversational analysis permitted to identify main topics to interpret data. Results showed that the interview was more arousing for the employee than the manager. Greater Delta and Theta EEG bands could denote positive valence of personal interactions and company mission topics. Autonomic measures (Skin Conductance Response, SCR and Heart Rate, HR) showed important information related to different leadership style. Results highlight the importance of applying neurosciences to organizational contexts exploring processes related to manager-employee dynamics and communicative style
The Receptor for Advanced Glycation End-products (RAGE) is only present in mammals, and belongs to a family of Cell Adhesion Molecules (CAMs)
The human receptor for advanced glycation endproducts (RAGE) is a multiligand cell surface protein belonging to the immunoglobulin superfamily, and is involved in inflammatory and immune responses. Most importantly, RAGE is considered a receptor for HMGB1 and several S100 proteins, which are Damage-Associated Molecular Pattern molecules (DAMPs) released during tissue damage. In this study we show that the Ager gene coding for RAGE first appeared in mammals, and is closely related to other genes coding for cell adhesion molecules (CAMs) such as ALCAM, BCAM and MCAM that appeared earlier during metazoan evolution. RAGE is expressed at very low levels in most cells, but when expressed at high levels, it mediates cell adhesion to extracellular matrix components and to other cells through homophilic interactions. Our results suggest that RAGE evolved from a family of CAMs, and might still act as an adhesion molecule, in particular in the lung where it is highly expressed or under pathological conditions characterized by an increase of its protein levels
New limits on nucleon decays into invisible channels with the BOREXINO Counting Test Facility
The results of background measurements with the second version of the
BOREXINO Counting Test Facility (CTF-II), installed in the Gran Sasso
Underground Laboratory, were used to obtain limits on the instability of
nucleons, bounded in nuclei, for decays into invisible channels ():
disappearance, decays to neutrinos, etc. The approach consisted of a search for
decays of unstable nuclides resulting from and decays of parents
C, C and O nuclei in the liquid scintillator and the water
shield of the CTF. Due to the extremely low background and the large mass (4.2
ton) of the CTF detector, the most stringent (or competitive) up-to-date
experimental bounds have been established: y, y, y and y, all at 90% C.L.Comment: 22 pages, 3 figures,submitted to Phys.Lett.
Search for displaced vertices arising from decays of new heavy particles in 7 TeV pp collisions at ATLAS
We present the results of a search for new, heavy particles that decay at a
significant distance from their production point into a final state containing
charged hadrons in association with a high-momentum muon. The search is
conducted in a pp-collision data sample with a center-of-mass energy of 7 TeV
and an integrated luminosity of 33 pb^-1 collected in 2010 by the ATLAS
detector operating at the Large Hadron Collider. Production of such particles
is expected in various scenarios of physics beyond the standard model. We
observe no signal and place limits on the production cross-section of
supersymmetric particles in an R-parity-violating scenario as a function of the
neutralino lifetime. Limits are presented for different squark and neutralino
masses, enabling extension of the limits to a variety of other models.Comment: 8 pages plus author list (20 pages total), 8 figures, 1 table, final
version to appear in Physics Letters
Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment
This paper describes an analysis of the angular distribution of W->enu and
W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with
the ATLAS detector at the LHC in 2010, corresponding to an integrated
luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and
the missing transverse energy, the W decay angular distribution projected onto
the transverse plane is obtained and analysed in terms of helicity fractions
f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV
and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw
> 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour,
are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017
+/- 0.030, where the first uncertainties are statistical, and the second
include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables,
revised author list, matches European Journal of Physics C versio
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