65 research outputs found
Mesenchymal/epithelial regulation of retinoic acid signaling in the olfactory placode
We asked whether mesenchymal/epithelial (M/E) interactions regulate retinoic acid (RA) signaling in the olfactory placode and whether this regulation is similar to that at other sites of induction, including the limbs, branchial arches, and heart. RA is produced by the mesenchyme at all sites, and subsets of mesenchymal cells express the RA synthetic enzyme RALDH2, independent of M/E interactions. In the placode, RA-producing mesenchyme is further distinguished by its coincidence with a molecularly distinct population of neural crest-associated cells. At all sites, expression of additional RA signaling molecules ( CRABP1) depends on M/E interactions. Of these molecules, RA regulates only , and this regulation depends on M/E interaction. Expression of and all of which are thought to influence RA signaling, is also regulated by M/E interactions independent of RA at all sites. Despite these common features, expression is distinct in the placode, as is regulation of and RALDH2 by Fgf8. Thus, M/E interactions regulate expression of RA receptors and cofactors in the olfactory placode and other inductive sites. Some aspects of regulation in the placode are distinct, perhaps reflecting unique roles for additional local signals in neuronal differentiation in the developing olfactory pathway
Mesenchymal/epithelial regulation of retinoic acid signaling in the olfactory placode
We asked whether mesenchymal/epithelial (M/E) interactions regulate retinoic acid (RA) signaling in the olfactory placode and whether this regulation is similar to that at other sites of induction, including the limbs, branchial arches, and heart. RA is produced by the mesenchyme at all sites, and subsets of mesenchymal cells express the RA synthetic enzyme RALDH2, independent of M/E interactions. In the placode, RA-producing mesenchyme is further distinguished by its coincidence with a molecularly distinct population of neural crest-associated cells. At all sites, expression of additional RA signaling molecules ( CRABP1) depends on M/E interactions. Of these molecules, RA regulates only , and this regulation depends on M/E interaction. Expression of and all of which are thought to influence RA signaling, is also regulated by M/E interactions independent of RA at all sites. Despite these common features, expression is distinct in the placode, as is regulation of and RALDH2 by Fgf8. Thus, M/E interactions regulate expression of RA receptors and cofactors in the olfactory placode and other inductive sites. Some aspects of regulation in the placode are distinct, perhaps reflecting unique roles for additional local signals in neuronal differentiation in the developing olfactory pathway
Stone cladding techniques in Modern Architecture 1922-1942
Leggere il progetto del Moderno e le sue culture costruttive in relazione alla storia e allo sviluppo della tecnologia, consente di esplorare alcuni aspetti dellâArchitettura Moderna in Europa. Oltre alla piĂč famosa, e maggiormente studiata, triade dei materiali âmoderniâ â lâacciaio, il calcestruzzo e il vetro â la pietra ha svolto un importante ruolo nella definizione sia dello stile che della costruzione moderna.
La costruzione in pietra Ăš stata sempre associata alla tradizione e quindi deliberatamente dimenticata dal Movimento Moderno, durante la fase cruciale della modernizzazione della societĂ e quindi dellâarchitettura e della costruzione. La pietra tuttavia testimonia la delicata transizione dalla tradizionale arte del costruire alle nuove tecnologie.
La ricerca ha studiato lâevoluzione delle tecniche costruttive in pietra in Francia ed in Italia, durante gli anni â20 e â30, in relazione alle nuove tecniche industrializzate e i linguaggi delle avanguardie. La ricerca Ăš partita dallo studio dei manuali, delle riviste e dei progetti presentati sulle loro pagine.
In Italia e in Francia il rivestimento in pietra si afferma come un sistema costruttivo ârazionaleâ, dove la costruzione moderna converge lentamente verso nuove soluzioni; questo sistema ha avuto negli anni â20 e â30 un ruolo centrale, nel quale Ăš stato possibile un dialogo, senza contraddizioni, tra i materiali âmoderniâ e la pietra.
Lâevoluzione dalle tradizionali tecniche costruttive verso i nuovi sistemi tecnologici, ha determinato una nuova costruzione in pietra che Ăš alla base di una modernitĂ che non rifiuta questo materiale tradizionale, ma lo trasforma secondo i nuoci principi estetici.Reading the project of the Modern and its constructive cultures in relation to the historical conditions and the technology, allows exploring some aspects of Modern Architecture in Europe. Besides the traditional, more studied and known triad of "moderns" materials, steel, concrete and glass, the stone also played an important role, in the definition both of "modern construction and modern style".
The construction in stone was always associated with the tradition and then forgotten by the Modern Movement, during the crucial phase of societyâs "modernization" and therefore its architecture and construction. The stone however explains this delicate transition from the traditional art of building in stone to the new technologies.
The research studies this evolution of construction techniques in stone in France and Italy during the '20s and '30s, related to the new industrialized construction and the avant-garde languages. It begins with the study of technical manuals, the reviews and the projects presented on its pages.
The stone cladding, in Italy and France, grows as a model of constructive rationality, where "modern" building techniques slowly converge toward to new solutions. The modern cladding in stone during the '20s '30s has a central role, where the dialogue is possible, without contradiction, between the materials so-called "modern" and the stone.
The evolution from traditional techniques to new technological systems determined a new construction in stone that is the basis of modernity and that doesnât reject this traditional material, but transforms it according to the new aesthetic principles
The Value of Information for Populations in Varying Environments
The notion of information pervades informal descriptions of biological
systems, but formal treatments face the problem of defining a quantitative
measure of information rooted in a concept of fitness, which is itself an
elusive notion. Here, we present a model of population dynamics where this
problem is amenable to a mathematical analysis. In the limit where any
information about future environmental variations is common to the members of
the population, our model is equivalent to known models of financial
investment. In this case, the population can be interpreted as a portfolio of
financial assets and previous analyses have shown that a key quantity of
Shannon's communication theory, the mutual information, sets a fundamental
limit on the value of information. We show that this bound can be violated when
accounting for features that are irrelevant in finance but inherent to
biological systems, such as the stochasticity present at the individual level.
This leads us to generalize the measures of uncertainty and information usually
encountered in information theory
Mitochondrial localization and function of a subset of 22q11 deletion syndrome candidate genes
Six genes in the 1.5 MB region of chromosome 22 deleted in DiGeorge/22q11 Deletion SyndromeâMrpl40, Prodh, Slc25a1, Txnrd2, T10, and Zdhhc8âencode mitochondrial proteins. All six genes are expressed in the brain, and maximal expression coincides with peak forebrain synaptogenesis shortly after birth. Furthermore, their protein products are associated with brain mitochondria, including those in synaptic terminals. Among the six, only Zddhc8 influences mitochondria-regulated apoptosis when overexpressed, and appears to interact biochemically with established mitochondrial proteins. Zdhhc8 has an apparent interaction with Uqcrc1, a component of mitochondrial complex III. The two proteins are coincidently expressed in presynaptic processes; however, Zdhhc8 is more frequently seen in glutamatergic terminals. 22q11 deletion may alter metabolic properties of cortical mitochondria during early post-natal life, since expression complex III components, including Uqcrc1, is significantly increased at birth in a mouse model of 22q11 deletion, and declines to normal values in adulthood. Our results suggest that altered dosage of one, or several 22q11 mitochondrial genes, particularly during early postnatal cortical development, may disrupt neuronal metabolism or synaptic signaling
Specific mesenchymal/epithelial induction of olfactory receptor, vomeronasal, and gonadotropin-releasing hormone (GnRH) neurons
We asked whether specific mesenchymal/epithelial (M/E) induction generates olfactory receptor neurons (ORNs), vomeronasal neurons (VRNs) and gonadotropin releasing hormone (GnRH) neuronsâthe major neuron classes associated with the olfactory epithelium (OE). To assess specificity of M/E-mediated neurogenesis, we compared the influence of frontonasal mesenchyme on frontonasal epithelium, which becomes the OE, with that of the forelimb bud. Despite differences in position, morphogenetic and cytogenic capacity, both mesenchymal tissues support neurogenesis, expression of several signaling molecules and neurogenic transcription factors in the frontonasal epithelium. Only frontonasal mesenchyme, however, supports OE-specific patterning and activity of a subset of signals and factors associated with OE differentiation. Moreover, only appropriate pairing of frontonasal epithelial and mesenchymal partners yields ORNs, VRNs, and GnRH neurons. Accordingly, the position and molecular identity of specialized frontonasal epithelia and mesenchyme early in gestation and subsequent inductive interactions, specifies the genesis and differentiation of peripheral chemosensory and neuroendocrine neurons
Measurement of the branching fraction
The branching fraction is measured in a data sample
corresponding to 0.41 of integrated luminosity collected with the LHCb
detector at the LHC. This channel is sensitive to the penguin contributions
affecting the sin2 measurement from The
time-integrated branching fraction is measured to be . This is the most precise measurement to
date
Measurement of the CP-violating phase \phi s in Bs->J/\psi\pi+\pi- decays
Measurement of the mixing-induced CP-violating phase phi_s in Bs decays is of
prime importance in probing new physics. Here 7421 +/- 105 signal events from
the dominantly CP-odd final state J/\psi pi+ pi- are selected in 1/fb of pp
collision data collected at sqrt{s} = 7 TeV with the LHCb detector. A
time-dependent fit to the data yields a value of
phi_s=-0.019^{+0.173+0.004}_{-0.174-0.003} rad, consistent with the Standard
Model expectation. No evidence of direct CP violation is found.Comment: 15 pages, 10 figures; minor revisions on May 23, 201
First observation of the decay and a measurement of the ratio of branching fractions
The first observation of the decay using
data collected by the LHCb detector at a centre-of-mass energy of 7 TeV,
corresponding to an integrated luminosity of 36 pb, is reported. A
signal of events is obtained and the absence of signal is
rejected with a statistical significance of more than nine standard deviations.
The branching fraction is measured relative to
that of : , where the first uncertainty is statistical, the second systematic and
the third is due to the uncertainty on the ratio of the and
hadronisation fractions.Comment: 10 pages, 3 figures, submitted to Phys. Lett. B; ISSN 0370-269
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