Talbot laser for Airy pulse generation

We report a C-band fiber Talbot laser –an injection-seeded frequency-shifting active ring cavity operated above threshold– emitting trains of far-field Airy pulses characterized by a dominant cubic spectral phase. Pulses are created by the coherent addition of the recirculating seed wavelength under a large roundtrip first-order dispersion. Single-sided Airy pulse trains with sub-ns pulse widths, 80-MHz repetition rate, and bandwidth exceeding 10 GHz are generated at both integer and fractional Talbot conditions. At detuned Talbot conditions pulses are shown to be tailorable by recirculation-induced first-order dispersion. The far-field character of the resulting waveforms is demonstrated, and the performance in terms of amplitude noise and timing jitter, in this last case after the introduction of active loop stabilization, is evaluated

Seed production determines the entrance to dormancy of the inflorescence meristem of Pisum sativum and the end of the flowering period

[EN] Flowering plants adjust their reproductive period to maximize the success of the offspring. Monocarpic plants, those with a single reproductive cycle that precedes plant senescence and death, tightly regulate both flowering initiation and flowering cessation. The end of the flowering period involves the arrest of the inflorescence meristem activity, known as proliferative arrest, in what has been interpreted as an evolutionary adaptation to maximize the allocation of resources to seed production and the viability of the progeny. Factors influencing proliferative arrest were described for several monocarpic plant species many decades ago, but only in the last few years studies performed in Arabidopsis have allowed to approach proliferative arrest regulation in a comprehensive manner by studying the physiology, hormone dynamics, and genetic factors involved in its regulation. However, these studies remain restricted to Arabidopsis and there is a need to expand our knowledge to other monocarpic species to propose general mechanisms controlling the process. In this work, we have characterized proliferative arrest in Pisum sativum, trying to parallel available studies in Arabidopsis to maximize this comparative framework. We have assessed quantitatively the role of fruits/seeds in the process, the influence of the positional effect of these fruits/seeds in the behavior of the inflorescence meristem, and the transcriptomic changes in the inflorescence associated with the arrested state of the meristem. Our results support a high conservation of the factors triggering arrest in pea and Arabidopsis, but also reveal differences reinforcing the need to perform similar studies in other species.Ministerio de Ciencia, Innovacion y Universidades, Grant/Award Number: FPU18/05599; Generalitat Valenciana, Grant/Award Number: CIPROM/2022/1 to C.F.; Spanish Agencia Estatal de Investigacion, Grant/Award Numbers: RTI2018-099239-B-I00, TED2021-129963B-I00Burillo, E.; Ortega, R.; Vander Schoor, JK.; Martínez-Fernández, I.; Weller, JL.; Bombarely, A.; Balanzà, V.... (2024). Seed production determines the entrance to dormancy of the inflorescence meristem of Pisum sativum and the end of the flowering period. Physiologia Plantarum. 176(4). https://doi.org/10.1111/ppl.14425176

Factors associated with interest in scientific research in dental students of six Cuban universities

"Introduction: To determine the factors associated with interest in scientific research in dental students of six Cuban universities. Methods: This is a multicenter cross-sectional analytical study. Interest in scientific research was the dependent variable, and it was assessed through a questionnaire proved to be reliable (Cronbach’s α= 0.88). We obtained adjusted prevalence ratios (aPR), 95% confidence intervals (95% CI), and p values through generalized linear models. Results: A total of 587 students were part of the research, and 57.9% manifested interest in scientific research. However, when they were asked if they wanted to pursue a research career in the future, only 45.1% responded affirmatively. We found, through multivariate analysis, that there was more interest in scientific research among those who were student assistants (aPR: 2.42; 95% CI: 1.41–4.16; p = 0.001), those who had previous studies (aPR: 1.35; 95% CI: 1.02–1.79; p = 0.034), and those who had received awards in scientific events (aPR: 1.74; 95% CI: 1.26–2.41; p = 0.001). In contrast, there was less interest among those who were at the clinical stage of their career (aPR: 0.66; 95% CI: 0.49–0.89; p = 0.006), adjusted for seven variables. Conclusions: There exists interest in scientific research and we found some factors associated with this. This has to be taken into account in order for educational institutions to generate strategies.

Factors associated with interest in scientific research in dental students of six Cuban universities

"Introduction: To determine the factors associated with interest in scientific research in dental students of six Cuban universities. Methods: This is a multicenter cross-sectional analytical study. Interest in scientific research was the dependent variable, and it was assessed through a questionnaire proved to be reliable (Cronbach’s α= 0.88). We obtained adjusted prevalence ratios (aPR), 95% confidence intervals (95% CI), and p values through generalized linear models. Results: A total of 587 students were part of the research, and 57.9% manifested interest in scientific research. However, when they were asked if they wanted to pursue a research career in the future, only 45.1% responded affirmatively. We found, through multivariate analysis, that there was more interest in scientific research among those who were student assistants (aPR: 2.42; 95% CI: 1.41–4.16; p = 0.001), those who had previous studies (aPR: 1.35; 95% CI: 1.02–1.79; p = 0.034), and those who had received awards in scientific events (aPR: 1.74; 95% CI: 1.26–2.41; p = 0.001). In contrast, there was less interest among those who were at the clinical stage of their career (aPR: 0.66; 95% CI: 0.49–0.89; p = 0.006), adjusted for seven variables. Conclusions: There exists interest in scientific research and we found some factors associated with this. This has to be taken into account in order for educational institutions to generate strategies.

Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum

Measurement of the t t-bar production cross section in the dilepton channel in pp collisions at sqrt(s) = 7 TeV

The t t-bar production cross section (sigma[t t-bar]) is measured in proton-proton collisions at sqrt(s) = 7 TeV in data collected by the CMS experiment, corresponding to an integrated luminosity of 2.3 inverse femtobarns. The measurement is performed in events with two leptons (electrons or muons) in the final state, at least two jets identified as jets originating from b quarks, and the presence of an imbalance in transverse momentum. The measured value of sigma[t t-bar] for a top-quark mass of 172.5 GeV is 161.9 +/- 2.5 (stat.) +5.1/-5.0 (syst.) +/- 3.6(lumi.) pb, consistent with the prediction of the standard model.Comment: Replaced with published version. Included journal reference and DO

Search for the standard model Higgs boson in the H to ZZ to 2l 2nu channel in pp collisions at sqrt(s) = 7 TeV

A search for the standard model Higgs boson in the H to ZZ to 2l 2nu decay channel, where l = e or mu, in pp collisions at a center-of-mass energy of 7 TeV is presented. The data were collected at the LHC, with the CMS detector, and correspond to an integrated luminosity of 4.6 inverse femtobarns. No significant excess is observed above the background expectation, and upper limits are set on the Higgs boson production cross section. The presence of the standard model Higgs boson with a mass in the 270-440 GeV range is excluded at 95% confidence level.Comment: Submitted to JHE

Combined search for the quarks of a sequential fourth generation

Results are presented from a search for a fourth generation of quarks produced singly or in pairs in a data set corresponding to an integrated luminosity of 5 inverse femtobarns recorded by the CMS experiment at the LHC in 2011. A novel strategy has been developed for a combined search for quarks of the up and down type in decay channels with at least one isolated muon or electron. Limits on the mass of the fourth-generation quarks and the relevant Cabibbo-Kobayashi-Maskawa matrix elements are derived in the context of a simple extension of the standard model with a sequential fourth generation of fermions. The existence of mass-degenerate fourth-generation quarks with masses below 685 GeV is excluded at 95% confidence level for minimal off-diagonal mixing between the third- and the fourth-generation quarks. With a mass difference of 25 GeV between the quark masses, the obtained limit on the masses of the fourth-generation quarks shifts by about +/- 20 GeV. These results significantly reduce the allowed parameter space for a fourth generation of fermions.Comment: Replaced with published version. Added journal reference and DO

Search for anomalous t t-bar production in the highly-boosted all-hadronic final state

A search is presented for a massive particle, generically referred to as a Z', decaying into a t t-bar pair. The search focuses on Z' resonances that are sufficiently massive to produce highly Lorentz-boosted top quarks, which yield collimated decay products that are partially or fully merged into single jets. The analysis uses new methods to analyze jet substructure, providing suppression of the non-top multijet backgrounds. The analysis is based on a data sample of proton-proton collisions at a center-of-mass energy of 7 TeV, corresponding to an integrated luminosity of 5 inverse femtobarns. Upper limits in the range of 1 pb are set on the product of the production cross section and branching fraction for a topcolor Z' modeled for several widths, as well as for a Randall--Sundrum Kaluza--Klein gluon. In addition, the results constrain any enhancement in t t-bar production beyond expectations of the standard model for t t-bar invariant masses larger than 1 TeV.Comment: Submitted to the Journal of High Energy Physics; this version includes a minor typo correction that will be submitted as an erratu