Micro-resonator soliton generated directly with a diode laser

An external-cavity diode laser is reported with ultralow noise, high power coupled to a fiber, and fast tunability. These characteristics enable the generation of an optical frequency comb in a silica micro-resonator with a single-soliton state. Neither an optical modulator nor an amplifier was used in the experiment. This demonstration greatly simplifies the soliton generation setup and represents a significant step forward to a fully integrated soliton comb system.Comment: 7 pages, 5 figure

Amélioration de la disponibilité du phosphore par la gestion de la macrofaune du sol : cas d’un lixisol en zone semi-aride du Burkina Faso

La carence en phosphore des sols de l’Afrique de l’Ouest constitue une contrainte majeure à l’intensification des systèmes de production agricole. Cette étude a été conduite pour évaluer les effets de l’interaction entre la macrofaune et des technologies de gestion de la fertilité des sols sur la disponibilité du phosphore d’un lixisol en zone semi-aride du Burkina Faso. Un dispositif expérimental en split-plot comprenant deux traitements principaux (parcelles avec et sans macrofaune) et cinq technologies de gestion de la fertilité des sols a été utilisé. La disponibilité du phosphore a été évaluée en utilisant la méthode Bray I. Les résultats montrent qu’il y a une interaction positive entre les technologies de gestion de la fertilité et la macrofaune du sol. La présence de la macrofaune a entraîné une augmentation significative du phosphore assimilable du sol. De même, l’apport de compost seul ou combiné à l’urée, augmente significativement la teneur en phosphore assimilable du sol. Ces résultats suggèrent de repenser les stratégies de protection des cultures, en réduisant et en utilisant de façon judicieuse les pesticides chimiques de synthèse. Les producteurs doivent en effet, adopter les biopesticides et les pesticides naturels afin de préserver la diversité biologique des sols agricoles.Mots clés : Macrofaune, qualité de la matière organique, phosphore assimilable, interaction Burkina Faso

Effet de la macrofaune et des modes de gestion de la fertilité sur le carbone d’un lixisol au Burkina Faso

La matière organique du sol est un élément déterminant de l’activité biologique, pour laquelle, la macrofaune du sol constitue un facteur important. Cette étude a été conduite pour appréhender les effets de la macrofaune et des modes de gestion de la fertilité des sols sur l’évolution du carbone d’un lixisol en zone semi-aride du Burkina Faso. Pour ce faire, un dispositif expérimental en split-plot à trois répétitions comprenant deux traitements principaux (parcelles avec et sans macrofaune) et quatre modes de gestion de la fertilité, a été mis en place. Les résultats ont montré que la macrofaune, les modes de gestion de la fertilité et leur interaction n’ont pas eu d’effet significatif (P > 0,05) sur le carbone total et l’indice de gestion du carbone à court terme. Toutefois, la macrofaune a augmenté l’indice de gestion du carbone de 35 % ; elle a également augmenté la teneur en carbone des différentes fractions granulométriques. L’interaction entre la macrofaune et les modes de gestion de la fertilité a amélioré le rendement du niébé. L’intensification écologique des agrosystèmes par un usage raisonné des pesticides chimiques de synthèse et un apport de matière organique, pourraient améliorer à long terme, la séquestration du carbone.Mots clés : Biologie des sols, séquestration du carbone, pesticides, Burkina Faso

Inhibition of caveolar uptake, SV40 infection, and β1-integrin signaling by a nonnatural glycosphingolipid stereoisomer

Caveolar endocytosis is an important mechanism for the uptake of certain pathogens and toxins and also plays a role in the internalization of some plasma membrane (PM) lipids and proteins. However, the regulation of caveolar endocytosis is not well understood. We previously demonstrated that caveolar endocytosis and β1-integrin signaling are stimulated by exogenous glycosphingolipids (GSLs). In this study, we show that a synthetic GSL with nonnatural stereochemistry, β-d-lactosyl-N-octanoyl-l-threo-sphingosine, (1) selectively inhibits caveolar endocytosis and SV40 virus infection, (2) blocks the clustering of lipids and proteins into GSLs and cholesterol-enriched microdomains (rafts) at the PM, and (3) inhibits β1-integrin activation and downstream signaling. Finally, we show that small interfering RNA knockdown of β1 integrin in human skin fibroblasts blocks caveolar endocytosis and the stimulation of signaling by a GSL with natural stereochemistry. These experiments identify a new compound that can interfere with biological processes by inhibiting microdomain formation and also identify β1 integrin as a potential mediator of signaling by GSLs

The role of photograph aesthetics on online review sites:Effects of management- versus traveler-generated photos on tourists’ decision-making

Tourists searching for information about destinations on online review sites areconcurrently exposed to two different photograph aesthetics, professional (produced by destination managers) and amateur (generated by travelers). While the former is glossy and sharp, the latter is often grainy and overexposed. Although aesthetics are important factors in tourist decision-making, the effects of the exposure to both types of photo aesthetics remain largely unexamined. This research investigates how both types of aesthetics, either singularly or in combination, affect a destination’s visual appeal and tourists’ booking intentionsthrough four controlled experiments (N = 1282). Our results show that despite the ‘messy’ beauty in amateur aesthetics, photos with professional aesthetics make a depicted destinationappear more visually appealing, ultimately driving booking intentions. However, the negative effects of amateur aesthetics are mitigated when (i) viewed by risk-averse tourists, (ii) presented alongside positive reviews, and (iii) accompanied by a greater number of professional photos

An Integrated-Photonics Optical-Frequency Synthesizer

Integrated-photonics microchips now enable a range of advanced functionalities for high-coherence applications such as data transmission, highly optimized physical sensors, and harnessing quantum states, but with cost, efficiency, and portability much beyond tabletop experiments. Through high-volume semiconductor processing built around advanced materials there exists an opportunity for integrated devices to impact applications cutting across disciplines of basic science and technology. Here we show how to synthesize the absolute frequency of a lightwave signal, using integrated photonics to implement lasers, system interconnects, and nonlinear frequency comb generation. The laser frequency output of our synthesizer is programmed by a microwave clock across 4 THz near 1550 nm with 1 Hz resolution and traceability to the SI second. This is accomplished with a heterogeneously integrated III/V-Si tunable laser, which is guided by dual dissipative-Kerr-soliton frequency combs fabricated on silicon chips. Through out-of-loop measurements of the phase-coherent, microwave-to-optical link, we verify that the fractional-frequency instability of the integrated photonics synthesizer matches the $7.0*10^{-13}$ reference-clock instability for a 1 second acquisition, and constrain any synthesis error to $7.7*10^{-15}$ while stepping the synthesizer across the telecommunication C band. Any application of an optical frequency source would be enabled by the precision optical synthesis presented here. Building on the ubiquitous capability in the microwave domain, our results demonstrate a first path to synthesis with integrated photonics, leveraging low-cost, low-power, and compact features that will be critical for its widespread use.Comment: 10 pages, 6 figure

Desenvolvimento e modelagem de quadrirrotor: um estudo de caso

TCC (graduação) - Universidade Federal de Santa Catarina. Centro Tecnológico. Engenharia Elétrica.Este trabalho apresenta um estudo sobre o desenvolvimento e modelagem de um veículo quadrirrotor. Este documento acompanha o processo de desenvolvimento de uma dessas aeronaves, partindo de um estudo sobre as principais dinâmicas de voo e características desse tipo de sistema. No estudo é apresentado um processo de caracterização usando as diferentes componentes do aparelho, o que permitiu a modelagem e simulação do sistema. É proposto também uma solução para implementação e controle a partir desse modelo simulado

Signals for CP-Violation in Scalar Tau Pair Production at Muon Colliders

We discuss signals for CP-violation in $\mu^+ \mu^- \to \tilde \tau_i^- \tilde \tau_j^+$, where $i,j = 1,2$ label the two scalar $\tau$ mass eigenstates. We assume that these reactions can proceed through the production and decay of the heavy neutral Higgs bosons present in supersymmetric models. CP-violation in the Higgs sector can be probed through a rate asymmetry even with unpolarized beams, while the CP-odd phase associated with the $\tilde \tau$ mass matrix can be probed only if the polarization of at least one beam can be varied. These asymmetries might be ${\cal O}(1)$.Comment: 9 pages, LaTeX with equations.sty, 3 PS figures (included

Niraparib and Abiraterone Acetate for Metastatic Castration-Resistant Prostate Cancer

PURPOSE: Metastatic castration-resistant prostate cancer (mCRPC) remains a lethal disease with current standard-of-care therapies. Homologous recombination repair (HRR) gene alterations, including BRCA1/2 alterations, can sensitize cancer cells to poly (ADP-ribose) polymerase inhibition, which may improve outcomes in treatment-naïve mCRPC when combined with androgen receptor signaling inhibition. METHODS: MAGNITUDE (ClinicalTrials.gov identifier: NCT03748641) is a phase III, randomized, double-blinded study that evaluates niraparib and abiraterone acetate plus prednisone (niraparib + AAP) in patients with (HRR+, n = 423) or without (HRR-, n = 247) HRR-associated gene alterations, as prospectively determined by tissue/plasma-based assays. Patients were assigned 1:1 to receive niraparib + AAP or placebo + AAP. The primary end point, radiographic progression-free survival (rPFS) assessed by central review, was evaluated first in the BRCA1/2 subgroup and then in the full HRR+ cohort, with secondary end points analyzed for the full HRR+ cohort if rPFS was statistically significant. A futility analysis was preplanned in the HRR- cohort. RESULTS: Median rPFS in the BRCA1/2 subgroup was significantly longer in the niraparib + AAP group compared with the placebo + AAP group (16.6 v 10.9 months; hazard ratio [HR], 0.53; 95% CI, 0.36 to 0.79; P = .001). In the overall HRR+ cohort, rPFS was significantly longer in the niraparib + AAP group compared with the placebo + AAP group (16.5 v 13.7 months; HR, 0.73; 95% CI, 0.56 to 0.96; P = .022). These findings were supported by improvement in the secondary end points of time to symptomatic progression and time to initiation of cytotoxic chemotherapy. In the HRR- cohort, futility was declared per the prespecified criteria. Treatment with niraparib + AAP was tolerable, with anemia and hypertension as the most reported grade ≥ 3 adverse events. CONCLUSION: Combination treatment with niraparib + AAP significantly lengthened rPFS in patients with HRR+ mCRPC compared with standard-of-care AAP