7,490 research outputs found
Quantum optical signals in telecommunication networks
Introducción a una red óptica metropolitana cuántica donde señales cuánticas y convencionales son multiplexadas en longitud de onda utilizando bandas separadas del espectro óptico. El enrutado se realiza con componentes pasivos para no perturbar los qubits. Se estudian dos redes: red de acceso WDM-PON y red metropolitana completa con backbone DWDM y redes de acceso WDM-PON
Measuring the W-t-b Interaction at the ILC
The large top quark mass suggests that the top plays a pivotal role in
Electroweak symmetry-breaking dynamics and, as a result, may have modified
couplings to Electroweak bosons. Hadron colliders can provide measurements of
these couplings at the ~10% level, and one of the early expected triumphs of
the International Linear Collider is to reduce these uncertainties to the per
cent level. In this article, we propose the first direct measurement of the
Standard Model W-t-b coupling at the ILC, from measurements of t tbar-like
signals below the t tbar production threshold. We estimate that the ILC with
100 fb^{-1} can measure a combination of the coupling and top width to high
precision, and when combined with a direct measurement of the top width from
the above-threshold scan, results in a model-independent measurement of the
W-t-b interaction of the order of ~ 3%
Distinguishing Patients With a Coordination Disorder From Healthy Controls Using Local Features of Movement Trajectories During the Finger-to-Nose Test
Assessment of coordination disorders is valuable for monitoring progression of patients, distinguishing healthy and pathological conditions, and ultimately aiding in clinical decision making, thereby offering the possibility to improve medical care or rehabilitation. A common method to assess movement disorders is by using clinical rating scales. However, rating scales depend on the evaluation and interpretation of an observer, implying that subjective phenotypic assignment precedes the application of the scales. Objective and more accurate methods are under continuous development but gold standards are still scarce. Here, we show how a method we previously developed, originally aimed at assessing dynamic balance by a probabilistic generalized linear model, can be used to assess a broader range of functional movements. In this paper, the method is applied to distinguish patients with coordination disorders from healthy controls. We focused on movements recorded during the finger-to-nose task (FNT), which is commonly used to assess coordination disorders. We also compared clinical FNT scores and model scores. Our method achieved 84% classification accuracy in distinguishing patients and healthy participants, using only two features. Future work could entail testing the reliability of the method by using additional features and other clinical tests such as finger chasing, quiet standing, and/or usage of tracking devices such as depth cameras or force plates
CHR11, a chromatin-remodeling factor essential for nuclear proliferation during female gametogenesis in Arabidopsis thaliana
Chromatin-remodeling factors regulate the establishment of transcriptional programs during plant development. Although 42 genes encoding members of the SWI2/SNF2 family have been identified in Arabidopsis thaliana, < 10 have been assigned a precise function on the basis of a mutant phenotype, and none have been shown to play a specific role during the gametophytic phase of the plant life cycle. A. thaliana chromatin-remodeling protein 11 (CHR11) encodes an imitation of switch (ISWI)-like chromatin-remodeling protein abundantly expressed during female gametogenesis and embryogenesis in Arabidopsis. To determine the function of CHR11 in wild-type plants, we introduced a hairpin construct leading to the production of double-stranded RNA, which specifically degraded the endogenous CHR11 mRNA by RNA interference (RNAi). Transcription of the RNAi-inducing hairpin RNA was driven by either a constitutive cauliflower mosaic virus 35S promoter (CaMV35S) acting at most stages of the sporophytic phase or a newly identified specific promoter acting at the onset of the female gametophytic phase (pFM1). All adult trans-formants that constitutively lacked sporophytic CHR11 activity showed reduced plant height and small cotyledonary embryos with limited cell expansion. In contrast, RNAi lines in which CHR11 was specifically silenced at the onset of female gametogenesis (megagametogenesis) had normal height and embryo size but had defective female gametophytes arrested before the completion of the mitotic haploid nuclear divisions. These results show that CHR11 is essential for haploid nuclear proliferation during megagametogenesis and cell expansion during the sporophytic phase, demonstrating the functional versatility of SW12/SNF2 chromatin-remodeling factors during both generations of the plant life cycle
Constraints on unparticle physics from the anomalous coupling
We study the impact of unparticle physics to the chromomagnetic dipole moment
(CMDM) of the top quark. We compute the effect induced by unparticle operators
of scalar and vector nature coupled to fermions on the CMDM. We find that this
dipole moment is sensitive to the scale dimensions of the unparticle and
the new couplings of the respective effective operators. Using the bounds
imposed on the CMDM by low-energy precision and Tevatron measurements we derive
indirect limits on the unparticle parameter space. In particular, we find that
the scalar-unparticle operator contribution fulfills both constraints for most
of the unparticle parameter space, while the low-energy precision bound on the
CMDM excludes a vector-unparticle contribution for low values of respective
scale dimension .Comment: 8 pages, 4 figure
Decomposition and nitrogen mineralisation of two wild lupins (Leguminosae) species with potential as green manures
The amount of biomass produced by various native species of genus Lupinus (L.) growing in Mexico ranges from 2.9- 8.2 Mg/ha of dry matter, which can add up to 200 kg/ha of N to soil as green manure. However, information is scarce on the decomposition and mineralisation this biomass in the soil. The above-ground decomposition and N mineralisation of Lupinus mexicanus Cerv. ex Lag. and Lupinus rotundiflorus M.E. Jones species from Mexico using fine-mesh litter bags was evaluated. Litter bags containing 5 g of above-ground air-dried biomass at the vegetative and flowering stages were buried at a depth of 20 cm. Were dug up every 3 weeks over the course of 4 months, dried and re-weighed to determine the lost mass and total N by the Kjeldahl method. The largest decrease in residue mass occurred during the first 3 weeks of incubation. However, the lost mass was higher in younger green manure (75 days old) than in older plants (85 days old) after 18 weeks of exposure in the field. It was found that 60-75% of the total N in the plant material was released in the first 6 weeks. In L. rotundiflorus green manure, it was found that 79.14% of the initial N in the vegetative stage and 77.6% of N in the flowering stage was released 18 weeks after litter bag installation, whereas L. mexicanus were 74.6% and 74.7%, respectively. It was found that both decomposition and N mineralisation occurred quickly in the green manures evaluated
Revisiting the T2K data using different models for the neutrino-nucleus cross sections
We present a three-flavour fit to the recent \nu\mu --> \nu e and \nu\mu -->
\nu\mu T2K oscillation data with different models for the neutrino-nucleus
cross section. We show that, even for a limited statistics, the allowed regions
and best fit points in the (\theta_{13},\delta_{CP}) and (\theta_{23},\Delta
m^2_{atm}) planes are affected if, instead of using the Fermi Gas model to
describe the quasielastic cross section, we employ a model including the
multinucleon emission channel.Comment: 13 pages, 12 figures. A new section on the inverted hierarchy added.
Version matching the published one in PL
Top quark tensor couplings
We compute the real and imaginary parts of the one-loop electroweak
contributions to the left and right tensorial anomalous couplings of the
vertex in the Standard Model (SM). For both tensorial couplings we find that
the real part of the electroweak SM correction is close to 10 of the leading
contribution given by the QCD gluon exchange. We also find that the electroweak
real and imaginary parts for the anomalous right coupling are almost of the
same order of magnitude. The one loop SM prediction for the real part of the
left coupling is close to the 3 discovery limit derived from
. Besides, taking into account that the predictions of
new physics interactions are also at the level of a few percents when compared
with the one loop QCD gluon exchange, these electroweak corrections should be
taken into account in order to disentangle new physics effects from the
standard ones. These anomalous tensorial couplings of the top quark will be
investigated at the LHC in the near future where sensitivity to these
contributions may be achieved.Comment: 16 pages, 2 figure
Vegetation Changes Following Biosolids Applications at an Old Boer Lovegrass Pasture in Northern Sonora, México
Short grass prairies (Bouteloua-Aristida) are the main vegetation type in northern Sonora, México, however, factors such as land fragmentation, overgrazing, severe droughts and lack of infrastructure in most ranches poor grazing management has caused land degradation. Boer lovegrass (Eragrostis curvula var. conferta) is an introduced species planted to increase productivity on deteriorated rangelands. Forage production with Boer lovegrass increases two to three fold as compared to native grasses after range seeding but productivity declines as stands become old. Biosolids have been recognized as a useful soil amendment and source of nitrogen, phosphorus, organic matter and other nutrients, which can enhance soil physical properties as well as plant yield (US Environmental Protection Agency 1999, Kinney et al. 2006). These organic compounds of human origins may play an important role in rangelands increasing soil fertility, however data do not exist to justify its use in México.
This study was conducted to evaluate forage responses of old Boer lovegrass stands to biosolids applications
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