1,404 research outputs found
Phosphodiesterases as therapeutic targets for respiratory diseases
Chronic respiratory diseases, such as chronic obstructive pulmonary disease (COPD) and asthma, affect millions of people all over the world. Cyclic adenosine monophosphate (cAMP) which is one of the most important second messengers, plays a vital role in relaxing airway smooth muscles and suppressing inflammation. Given its vast role in regulating intracellular responses, cAMP provides an attractive pharmaceutical target in the treatment of chronic respiratory diseases. Phosphodiesterases (PDEs) are enzymes that hydrolyze cyclic nucleotides and help control cyclic nucleotide signals in a compartmentalized manner. Currently, the selective PDE4 inhibitor, roflumilast, is used as an add-on treatment for patients with severe COPD associated with bronchitis and a history of frequent exacerbations. In addition, other novel PDE inhibitors are in different phases of clinical trials. The current review provides an overview of the regulation of various PDEs and the potential application of selective PDE inhibitors in the treatment of COPD and asthma. The possibility to combine various PDE inhibitors as a way to increase their therapeutic effectiveness is also emphasized
Interação de plantas daninhas com insetos no sistema sucessional soja e feijão-caupi no estado de Goiás.
O objetivo do trabalho foi avaliar a interação de plantas daninhas com insetos no sistema sucessional soja e feijão-caupi. O experimento foi conduzido no Instituto Federal Goiano, campus Morrinhos, Goiás.Resumo expandido
Interação de plantas daninhas com insetos no sistema sucessional soja e feijão-caupi no estado de Goiás.
O objetivo do trabalho foi avaliar a interação de plantas daninhas com insetos no sistema sucessional soja e feijão-caupi. O experimento foi conduzido no Instituto Federal Goiano, campus Morrinhos, Goiás.Resumo expandido
Arranjo de plantas no desempenho do híbrido de tomate para processamento industrial BRS Sena.
Objetivou-se com este trabalho avaliar diferentes arranjos de plantas para o híbrido de tomate para processamento industrial BRS Sena, considerando duas épocas de transplante: mês de fevereiro (ano de 2012) e mês de abril (ano de 2013).Resumo 1
Driving magnetic order in a manganite by ultrafast lattice excitation
Optical control of magnetism, of interest for high-speed data processing and
storage, has only been demonstrated with near-infrared excitation to date.
However, in absorbing materials, such high photon energies can lead to
significant dissipation, making switch back times long and miniaturization
challenging. In manganites, magnetism is directly coupled to the lattice, as
evidenced by the response to external and chemical pressure, or to
ferroelectric polarization. Here, femtosecond mid-infrared pulses are used to
excite the lattice in La0.5Sr1.5MnO4 and the dynamics of electronic order are
measured by femtosecond resonant soft x-ray scattering with an x-ray free
electron laser. We observe that magnetic and orbital orders are reduced by
excitation of the lattice. This process, which occurs within few picoseconds,
is interpreted as relaxation of the complex charge-orbital-spin structure
following a displacive exchange quench - a prompt shift in the equilibrium
value of the magnetic and orbital order parameters after the lattice has been
distorted. A microscopic picture of the underlying unidirectional lattice
displacement is proposed, based on nonlinear rectification of the
directly-excited vibrational field, as analyzed in the specific lattice
symmetry of La0.5Sr1.5MnO4. Control of magnetism through ultrafast lattice
excitation has important analogies to the multiferroic effect and may serve as
a new paradigm for high-speed optomagnetism.Comment: 10 pages manuscript, 4 figure
Variability of aerosol vertical distribution in the Sahel
In this work, we have studied the seasonal and inter-annual variability of the aerosol vertical distribution over Sahelian Africa for the years 2006, 2007 and 2008, characterizing the different kind of aerosols present in the atmosphere in terms of their optical properties observed by ground-based and satellite instruments, and their sources searched for by using trajectory analysis. This study combines data acquired by three ground-based micro lidar systems located in Banizoumbou (Niger), Cinzana (Mali) and M'Bour (Senegal) in the framework of the African Monsoon Multidisciplinary Analysis (AMMA), by the AEROsol RObotic NETwork (AERONET) sun-photometers and by the space-based Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) onboard the CALIPSO satellite (Cloud-Aerosol Lidar and Infrared Pathfinder Observations). <br><br> During winter, the lower levels air masses arriving in the Sahelian region come mainly from North, North-West and from the Atlantic area, while in the upper troposphere air flow generally originates from West Africa, crossing a region characterized by the presence of large biomass burning sources. The sites of Cinzana, Banizoumbou and M'Bour, along a transect of aerosol transport from East to West, are in fact under the influence of tropical biomass burning aerosol emission during the dry season, as revealed by the seasonal pattern of the aerosol optical properties, and by back-trajectory studies. <br><br> Aerosol produced by biomass burning are observed mainly during the dry season and are confined in the upper layers of the atmosphere. This is particularly evident for 2006, which was characterized by a large presence of biomass burning aerosols in all the three sites. <br><br> Biomass burning aerosol is also observed during spring when air masses originating from North and East Africa pass over sparse biomass burning sources, and during summer when biomass burning aerosol is transported from the southern part of the continent by the monsoon flow. <br><br> During summer months, the entire Sahelian region is under the influence of Saharan dust aerosols: the air masses in low levels arrive from West Africa crossing the Sahara desert or from the Southern Hemisphere crossing the Guinea Gulf while in the upper layers air masses still originate from North, North-East. The maximum of the desert dust activity is observed in this period which is characterized by large AOD (above 0.2) and backscattering values. It also corresponds to a maximum in the extension of the aerosol vertical distribution (up to 6 km of altitude). In correspondence, a progressive cleaning up of the lowermost layers of the atmosphere is occurring, especially evident in the Banizoumbou and Cinzana sites. <br><br> Summer is in fact characterized by extensive and fast convective phenomena. <br><br> Lidar profiles show at times large dust events loading the atmosphere with aerosol from the ground up to 6 km of altitude. These events are characterized by large total attenuated backscattering values, and alternate with very clear profiles, sometimes separated by only a few hours, indicative of fast removal processes occurring, likely due to intense convective and rain activity. <br><br> The inter-annual variability in the three year monitoring period is not very significant. An analysis of the aerosol transport pathways, aiming at detecting the main source regions, revealed that air originated from the Saharan desert is present all year long and it is observed in the lower levels of the atmosphere at the beginning and at the end of the year. In the central part of the year it extends upward and the lower levels are less affected by air masses from Saharan desert when the monsoon flow carries air from the Guinea Gulf and the Southern Hemisphere inland
The AMMA mulid network for aerosol characterization in West Africa
Three ground based portable low power consumption microlidars (MULID) have
been built and deployed at three remote sites in Banizoumbou (Niger), Cinzana
(Mali) and M'Bour (Senegal) in the framework of the African Monsoon
Multidisciplinary Analyses (AMMA) project for the characterization of aerosols
optical properties. A description of the instrument and a discussion of the
data inversion method, including a careful analysis of measurement
uncertainties (systematic and statistical errors) are presented. Some case
studies of typical lidar profiles observed over the Banizoumbou site during
2006 are shown and discussed with respect to the AERONET 7-day
back-trajectories and the biomass burning emissions from the Combustion
Emission database for the AMMA campaign
Filosofia di Berlusconi: l'essere e il nulla nell'Italia del Cavaliere
La filosofia, diceva Hegel, \ue8 come la nottola di Minerva, che "spicca il volo sul far della sera", ossia inizia a prendere la parola sugli eventi solo quando sono compiuti e si avviano verso il declino. Lo scenario da basso impero del crepuscolo del berlusconismo \ue8 quindi il momento giusto per fare i conti con un fenomeno che \ue8 stato la cifra dominante dell'ultimo ventennio di storia italiana, ma la cui rilevanza va ben oltre il ristretto panorama delle vicende nostrane. Per comprendere ci\uf2 che all'apparenza risulta incomprensibile non bastano le analisi di tipo sociologico, semiologico o politologico, che pure in queste anni non sono mancate, ma sono necessari altri strumenti per individuare la logica, la narrativa, la fisica e la metafisica che hanno reso possibile la drammatica trasformazione della nostra quotidianit\ue0 in un perverso intreccio di menzogne, barzellette, millanterie e volgarit\ue0, sullo sfondo di una sistematica, sprezzante opera di demolizione e privatizzazione delle istituzioni
Reconstructing the spectrum of the pregalactic density field from astronomical data
In this paper we evaluate the spectrum of the pregalactic density field on
scales Mpc from a variety of astronomical data. APM
data on in six narrow magnitude is used, after correcting to
possible evolutionary effects, to constrain the spectrum of galaxy clustering
on scales . Fitting power spectra of CDM
models to the data at all depths requires if the primordial
index and if the spectrum is tilted with . Then we
compare the peculiar velocity field predicted by the APM spectrum of galaxy
(light) distribution with the actual velocity data. The two fields are
consistent and the comparison suggests that the bias factor is scale
independent with (0.2-0.3). The next dataset used comes
from the cluster correlation data. We calculate in detail the amplification of
the cluster correlation function due to gravitational clustering and use the
data on both the slope of the cluster correlation function and its
amplitude-richness dependence. Cluster masses are normalized using the Coma
cluster. We find that CDM models are hard to reconcile with all the three
datasets: APM data on , the data on cluster correlation function,
and the data on the latter's amplitude-richness dependence. We show that the
data on the amplitude-richness dependence can be used directly to obtain the
spectrum of the pregalactic density field. Applying the method to the data, we
recover the density field on scales between 5 and 25Mpc whose slope is
in good agreement with the APM data on the same scales. Requiring the two
amplitudes to be the same, fixes the value of to be 0.3 in agreement
with observations of the dynamics of the Coma cluster. Finally we use the dataComment: to be published in Ap.J - minor revision + typos correcte
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