Understanding soil processes is fundamental to the success of forest restoration programs. We compared different types of soils in Mediterranean mountain forests with respect to their edaphic ...environments and influence of vegetation cover and lithology. We then used this information to determine the suitability of current forest restoration programs in these ecosystems.
Twenty-four surface horizons in forest soils in two zones of contrasting lithology (calcareous and metamorphic) and different types of vegetation cover or management (shrubland, autochthonous forest and reforested forest) were sampled. A set of their essential soil properties were analysed and a series of parameters considered as indicators of surface soil processes was selected: aggregate size, structural stability, water repellency, mineralisation rate and fungal activity.
Results confirm that the lithological origins of soils determines the properties defined by the geochemical environment of soilscapes (texture, pH, exchange complex and free oxides), and does not much influence organic properties. On the other hand, the type of plant cover and management do not influence the geochemical properties of the soil decisively, but do maintain a relative control of organic properties, especially those that define their quality (C/N ratio).
The variability of surface properties is not well explained by environmental factors, and it is assumed that a large part may be related to the historical use of the soils.
The specificity of soilscapes implies differences in vulnerability to forest management: the surface horizons in siliceous environments are more vulnerable than calcareous environments. It is necessary to better characterize soil properties in these forests and accordingly re-evaluate forest restoration efforts with respect to them.
The LHCb experiment at CERN has decided to optimise its physics reach by removing the first level hardware trigger for 2020 and beyond. In addition to requiring fully redesigned front-end electronics ...this design creates interesting challenges for the data-acquisition and the rest of the online computing system. Such a system can only be realized within realistic cost using as much off-the-shelf hardware as possible. Relevant technologies evolve very quickly and thus the system design is architecture-centred and tries to avoid to depend too much on specific technologies. In this paper we describe the design, the motivations for various choices and the current favoured options for the implementation, and the status of the R&D. We will cover the back-end readout, which contains the only custom-made component, the event-building, the event-filter infrastructure, and storage.
The architecture of the data acquisition system foreseen for the LHCb upgrade, to be installed by 2018, is devised to readout events trigger-less, synchronously with the LHC bunch crossing rate at 40 ...MHz. Within this approach the readout boards act as a bridge between the front-end electronics and the High Level Trigger (HLT) computing farm. The baseline design for the LHCb readout is an ATCA board requiring dedicated crates. A local area standard network protocol is implemented in the on-board FPGAs to read out the data. The alternative solution proposed here consists in building the readout boards as PCIe peripherals of the event-builder servers. The main architectural advantage is that protocol and link-technology of the event-builder can be left open until very late, to profit from the most cost-effective industry technology available at the time of the LHC LS2.
Thomasini RL, Bonon SH, Durante P, Costa SCB. Correlation of cytomegalovirus and human herpesvirus7 with CD3|>+|>and CD3|> +|>CD4+|>cells in chronic periodontitis patients. J Periodont Res 2012; 47: ...114-120. copy 2011 John Wiley & Sons A/S Background and Objective: Human chronic periodontitis is an inflammatory process characterized by dense accumulation of immune cells in the periodontal tissue. The periodontitis can lead to loss of teeth in the patient and the pathogenesis of this disease is not completely known. This study tested the hypothesis that chronic periodontitis-affected sites can harbor betaherpesviruses and that viruses are linked to a profile of the inflammatory infiltrate. Material and Methods: Biopsies of periodontal tissue were taken from periodontitis-affected patients and from healthy subjects. Immunohistochemistry was performed to count CD19+ Bcells, CD3+ total Tcells, T-CD4+ and T-CD8+ cell subsets, and PCR was performed to detect cytomegalovirus and human herpesvirus6 and 7 in the samples. One slide of each sample was stained with Giemsa for histopathological examination and to evaluate the quality of the cellular infiltrate. Results: As expected, tissues collected from healthy subjects presented no significant level of inflammatory infiltration and were therefore excluded from immunostaining procedures. Results showed that CD19+ Bcells were in higher number than CD3+ Tcells in the periodontitis-affected tissue, but this was not statistically significant. The T-CD4+ lymphocyte subset was significantly higher than the T-CD8+ lymphocyte subset (p=0.004) in the samples. Cytomegalovirus and human herpesvirus7 were found at periodontitis-affected sites, but not in tissue collected from healthy subjects (p=0.04 and p=0.04, respectively). Human herpesvirus6 was rarely detected. We found a correlation between cytomegalovirus and lower CD19+/CD3+ ratios (ratio <0.9, p=0.003) and between human herpesvirus7 and lower CD19 super(+)/CD3 super(+) ratios (ratio <0.9, p=0.003) and higher CD4 super(+)/CD8 super(+) ratios (ratio >1.1, p=0.002). Conclusion: This study shows that cytomegalovirus and human herpesvirus7 can be present at periodontitis-affected sites but are uncommon at healthy periodontal sites. Moreover, our data suggest that cytomegalovirus can be related to an inflammatory infiltrate with predominance of CD3+ Tcells, whereas human herpesvirus7 can be associated with an infiltrate with predominance of T-CD4+ cells. However, further studies are necessary to support this hypothesis. Herpesviruses could play a role in human chronic periodontitis by modulation of the Tcell response.
This paper presents the design, fabrication and characterization of a QWIP photodetector capable of detecting simultaneously infrared radiation within near infrared (NIR), mid wavelength infrared ...(MWIR) and long wavelength infrared (LWIR). The NIR detection was achieved using interband transition while MWIR and LWIR were based on intersubband transition in the conduction band. The quantum well structure was designed using a computational tool developed to solve self-consistently the Schrödinger–Poisson equation with the help of the shooting method. Intersubband absorption in the sample was measured for the MWIR and LWIR using Fourier transform spectroscopy (FTIR) and the measured peak positions were found at 5.3μm and 8.7μm which agree well with the theoretical values obtained 5.0μm and 9.0μm for the two infrared bands which indicates the accuracy of the self-consistent model. The photodetectors were fabricated using a standard photolithography process with exposed middle contacts to allow separate bias and readout of signals from the three wavelength bands. The measured photoresponse gave three peaks at 0.84μm, 5.0μm and 8.5μm wavelengths with approximately 0.5A/W, 0.03A/W and 0.13A/W peak responsivities for NIR, MWIR and LWIR bands, respectively. This work demonstrates the possibility of detection of widely separated wavelength bands using interband and intersubband transitions in quantum wells.
A narrow pentaquark state, Pc(4312)+, decaying to J/ψp, is discovered with a statistical significance of 7.3σ in a data sample of Λb0→J/ψpK− decays, which is an order of magnitude larger than that ...previously analyzed by the LHCb Collaboration. The Pc(4450)+ pentaquark structure formerly reported by LHCb is confirmed and observed to consist of two narrow overlapping peaks, Pc(4440)+ and Pc(4457)+, where the statistical significance of this two-peak interpretation is 5.4σ. The proximity of the Σc+D¯0 and Σc+D¯*0 thresholds to the observed narrow peaks suggests that they play an important role in the dynamics of these states.
The ratio of branching fractions R ( D * − ) ≡ B ( B 0 → D * − τ + ν τ ) / B ( B 0 → D * − μ + ν μ ) is measured using a data sample of proton-proton collisions collected with the LHCb detector at ...center-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of 3 fb − 1 . For the first time, R ( D * − ) is determined using the τ -lepton decays with three charged pions in the final state. The B 0 → D * − τ + ν τ yield is normalized to that of the B 0 → D * − π + π − π + mode, providing a measurement of B ( B 0 → D * − τ + ν τ ) / B ( B 0 → D * − π + π − π + ) = 1.97 ± 0.13 ± 0.18 , where the first uncertainty is statistical and the second systematic. The value of B ( B 0 → D * − τ + ν τ ) = ( 1.42 ± 0.094 ± 0.129 ± 0.054 ) % is obtained, where the third uncertainty is due to the limited knowledge of the branching fraction of the normalization mode. Using the well-measured branching fraction of the B 0 → D * − μ + ν μ decay, a value of R ( D * − ) = 0.291 ± 0.019 ± 0.026 ± 0.013 is established, where the third uncertainty is due to the limited knowledge of the branching fractions of the normalization and B 0 → D * − μ + ν μ modes. This measurement is in agreement with the standard model prediction and with previous results.
Observation of the Doubly Charmed Baryon Ξ++cc Alfonso Albero, Alejandro; Badalov, Alexey; Calvo Gómez, Míriam ...
Physical review letters,
09/2017, Letnik:
119, Številka:
11
Journal Article
Recenzirano
Odprti dostop
A highly significant structure is observed in the Λc+K-π+π+ mass spectrum, where the Λc+ baryon is reconstructed in the decay mode p K-π+. The structure is consistent with originating from a weakly ...decaying particle, identified as the doubly charmed baryon Ξcc ++. The difference between the masses of the Ξcc ++ and Λc+ states is measured to be 1334.94 ±0.72 (stat.) ±0.27 (syst. ) MeV /c2 , and the Ξcc ++ mass is then determined to be 3621.40 ±0.72 (stat.) ±0.27 (syst. ) ±0.14 (Λc+) MeV /c2 , where the last uncertainty is due to the limited knowledge of the Λc+ mass. The state is observed in a sample of proton-proton collision data collected by the LHCb experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 1.7 fb-1, and confirmed in an additional sample of data collected at 8 TeV.
The branching fraction ratio R(D^{*})≡B(Bover ¯^{0}→D^{*+}τ^{-}νover ¯_{τ})/B(Bover ¯^{0}→D^{*+}μ^{-}νover ¯_{μ}) is measured using a sample of proton-proton collision data corresponding to 3.0 ...fb^{-1} of integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The tau lepton is identified in the decay mode τ^{-}→μ^{-}νover ¯_{μ}ν_{τ}. The semitauonic decay is sensitive to contributions from non-standard-model particles that preferentially couple to the third generation of fermions, in particular, Higgs-like charged scalars. A multidimensional fit to kinematic distributions of the candidate Bover ¯^{0} decays gives R(D^{*})=0.336±0.027(stat)±0.030(syst). This result, which is the first measurement of this quantity at a hadron collider, is 2.1 standard deviations larger than the value expected from lepton universality in the standard model.
The ratio of branching fractions R(D*−)≡B(B0→D*−τ+ντ)/B(B0→D*−μ+νμ) is measured using a data sample of proton-proton collisions collected with the LHCb detector at center-of-mass energies of 7 and 8 ...TeV, corresponding to an integrated luminosity of 3 fb−1. The τ lepton is reconstructed with three charged pions in the final state. A novel method is used that exploits the different vertex topologies of signal and backgrounds to isolate samples of semitauonic decays of b hadrons with high purity. Using the B0→D*−π+π−π+ decay as the normalization channel, the ratio B(B0→D*−τ+ντ)/B(B0→D*−π+π−π+) is measured to be 1.97±0.13±0.18, where the first uncertainty is statistical and the second systematic. An average of branching fraction measurements for the normalization channel is used to derive B(B0→D*−τ+ντ)=(1.42±0.094±0.129±0.054)%, where the third uncertainty is due to the limited knowledge of B(B0→D*−π+π−π+). A test of lepton flavor universality is performed using the well-measured branching fraction B(B0→D*−μ+νμ) to compute R(D*−)=0.291±0.019±0.026±0.013, where the third uncertainty originates from the uncertainties on B(B0→D*−π+π−π+) and B(B0→D*−μ+νμ). This measurement is in agreement with the Standard Model prediction and with previous measurements.
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