959 research outputs found

    Lensing of ultra-high energy cosmic rays in turbulent magnetic fields

    Get PDF
    We consider the propagation of ultra high energy cosmic rays through turbulent magnetic fields and study the transition between the regimes of single and multiple images of point-like sources. The transition occurs at energies around EcZ 41EeV(Brms/5μG)(L/2kpc)3/250pc/LcE_c\simeq Z~41 {\rm EeV}(B_{rms}/5 \mu{\rm G}) (L/ 2 {\rm kpc})^{3/2}\sqrt{50 {\rm pc}/L_c}, where LL is the distance traversed by the CR's with electric charge ZeZe in the turbulent magnetic field of root mean square strength BrmsB_{rms} and coherence length LcL_c. We find that above 2Ec2 E_c only sources located in a fraction of a few % of the sky can reach large amplifications of its principal image or start developing multiple images. New images appear in pairs with huge magnifications, and they remain amplified over a significant range of energies. At decreasing energies the fraction of the sky in which sources can develop multiple images increases, reaching about 50% for E>Ec/2E>E_c/2. The magnification peaks become however increasingly narrower and for E<Ec/3E<E_c/3 their integrated effect becomes less noticeable. If a uniform magnetic field component is also present it would further narrow down the peaks, shrinking the energy range in which they can be relevant. Below EEc/10E\simeq E_c/10 some kind of scintillation regime is reached, where many demagnified images of a source are present but with overall total magnification of order unity. We also search for lensing signatures in the AGASA data studying two-dimensional correlations in angle and energy and find some interesting hints.Comment: 30 pages, 16 figures, final version with minor change

    Comparison of field measurement methods of nitrous oxide soil emissions: from the chamber to the vial

    Get PDF
    Nitrous oxide (N2O) is a greenhouse gas that contributes substantially to global climate change. The N2O soil emissions have a large uncertainty because of its low atmospheric concentration levels and enormous spatial and temporal variability, which hinders its correct field measurement. For this reason, there are many papers focused on improving the N2O measurements in the field, which focus on different parts of the measurement process. However, no studies have focused on determining the appropriate method, in terms of simplicity and precision, for the sample extraction from inside of the chambers and its transfer to the storage vials, although this step is key in the sampling process. This study aimed to assess and compare the accuracies of three simple and economical methods in transfer soil emitted N2O from inside of the chambers to the vials. For this, a highly accepted method (vacuum by manual pump) and two simpler alternative methods (gas exchange by displacement and vacuum by syringe) were compared. Thirty static chambers were assessed with the quantified N2O emission values varied from 0 to 450 µg m-2 h-1 of N-N2O. Out of the three assessed methods, the vacuum method through the use of a manual vacuum pump was the best to quantifying N2O soil emissions (capturing 57 % of the highest emission values), followed by the gas exchange method by displacement (30 %), and finally by the vacuum method by syringe extraction (13%).Fil: Cosentino, Vanina Rosa Noemi. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Suelos; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Cátedra de Fertilidad y Fertilizantes; ArgentinaFil: Romaniuk, Romina Ingrid. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Suelos; ArgentinaFil: Lupi, Ana Maria. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de suelos; ArgentinaFil: Gomez, Federico. Universidad de Buenos Aires. Facultad de Agronomía. Cátedra de Fertilidad y Fertilizantes; Argentina.Fil Rimski Korsakov, Helena Universidad de Buenos Aires, Facultad de Agronomía, Ciudad Autónoma de Buenos Aires, Buenos Aires, ArgentinaFil: Alvarez, Carina Rosa. Universidad de Buenos Aires. Facultad de Agronomía; ArgentinaFil: Ciarlo, Esteban Universidad de Buenos Aires, Facultad de Agronomía, Ciudad Autónoma de Buenos Aires, Argentin

    Physicochemical Quality, Antioxidant Capacity and Nutritional Value in Tuberous Roots of Some Wild Dahlia Species

    Get PDF
    The aim of this research was to evaluate the physicochemical quality, antioxidant capacity and nutritional value in tuberous roots of some wild dahlia species. The experiment was carried out in the Department of Plant Science of the Autonomous University Chapingo, Mexico. Plants were established in a randomized complete block design with five replications. The total soluble solids (TSS), titratable acidity (TA), vitamin C (VC), total phenols (TP), antioxidant capacity (AC), inulin and its proximate composition were evaluated. Among the materials analyzed, the most outstanding wild species were Dahlia campanulata, D. coccinea and D. brevis, where D. campanulata stood out for its concentration of VC (0.05 mg 100 g-1), AC (1.88 mg VCEAC g-1), inulin, DM and TC (72.25, 24.38 and 88.37%, respectively), however, the inulin content was similar to D. coccinea (66.17%), which was also outstanding with respect to the content of TP (1.74 mg GA g-1). Likewise, D. brevis presented the highest values of RFi (5.49%) and A (78.42%). According to our results, the tuberous roots of wild dahlia species can be used as food, as well as being a source of selection of traits of nutraceutic interest for genetic improvement

    Precision measurement of the neutrino velocity with the ICARUS detector in the CNGS beam

    Get PDF
    During May 2012, the CERN-CNGS neutrino beam has been operated for two weeks for a total of 1.8 10^17 pot in bunched mode, with a 3 ns narrow width proton beam bunches, separated by 100 ns. This tightly bunched beam structure allows a very accurate time of flight measurement of neutrinos from CERN to LNGS on an event-by-event basis. Both the ICARUS-T600 PMT-DAQ and the CERN-LNGS timing synchronization have been substantially improved for this campaign, taking ad-vantage of additional independent GPS receivers, both at CERN and LNGS as well as of the deployment of the "White Rabbit" protocol both at CERN and LNGS. The ICARUS-T600 detector has collected 25 beam-associated events; the corresponding time of flight has been accurately evaluated, using all different time synchronization paths. The measured neutrino time of flight is compatible with the arrival of all events with speed equivalent to the one of light: the difference between the expected value based on the speed of light and the measured value is tof_c - tof_nu = (0.10 \pm 0.67stat. \pm 2.39syst.) ns. This result is in agreement with the value previously reported by the ICARUS collaboration, tof_c - tof_nu = (0.3 \pm 4.9stat. \pm 9.0syst.) ns, but with improved statistical and systematic errors.Comment: 21 pages, 13 figures, 1 tabl

    Studi Implementasi Pendidikan Karakter Pada Pembelajaran Matematika Pada Kelas Cerdas Istimewa Bakat Istimewa (Cibi) SMP Negeri 2 Surakarta

    Full text link
    The objective of research was to describe the implementation of character education to mathematics learning, the constraints the teacher faced and the solution the teachers took to the constraints with the implementation of character education in mathematics learning in the gifted and talented class of SMP Negeri 2 Surakarta. This study was a descriptive qualitative research; the subject of researcher was one mathematics teacher and six students in the grade VII gifted and talented class. Techniques of validating data used were researcher persistence and time triangulation. Techniques of analyzing data used were (1) data reduction, (2) data display, and (3) conclusion drawing and verification. The results of research are as follows. 1) The process of character education implementation to learning was below. (a) The development of logical, critical, creative and innovative thinking character was conducted by means of assignment, directing the students to the correct answer and to make decision with debriefing. (b) The development of hard work character was conducted by means of group assignment. (c) The development of curiosity character was conducted by providing the example of material existing in real life. (d) The development of independency character was conducted by assigning the material reading to be discussed in the next meeting. (e) The development of self-confidence character was conducted by means of facilitating the students writing the result on the blackboard. 2) The constraints the teacher faced and the solutions the teacher took were as follows. (a) In the implementation of logical, critical, creative and innovative thinking character, the students monopolized actively the debriefing process so that the teacher should limit and provide other students the opportunity of asking question. (b) In the implementation of hard work character, not all students in the classroom had equal hard work ethos. The solutions taken were to play motivation video and to convince them about the ability they had, to display the students\u27 work, and to reward the students with the best performance. (c) In the implementation of curiosity character, the students who did not want to think too hard responded poorly to the stimulus given. In this case, the teacher could give reward in the form of mark (grade). (d) In the implementation of self-confidence character, the students with less self-confidence would select the easy assignment in presenting the group assignment, and they explained in very soft voice. The solutions taken were to give more mark to the students explaining group assignment, and to direct the students in the presentation. For teacher independency character, the teacher did not face a significant constraint

    Solitary waves in the Nonlinear Dirac Equation

    Get PDF
    In the present work, we consider the existence, stability, and dynamics of solitary waves in the nonlinear Dirac equation. We start by introducing the Soler model of self-interacting spinors, and discuss its localized waveforms in one, two, and three spatial dimensions and the equations they satisfy. We present the associated explicit solutions in one dimension and numerically obtain their analogues in higher dimensions. The stability is subsequently discussed from a theoretical perspective and then complemented with numerical computations. Finally, the dynamics of the solutions is explored and compared to its non-relativistic analogue, which is the nonlinear Schr{\"o}dinger equation. A few special topics are also explored, including the discrete variant of the nonlinear Dirac equation and its solitary wave properties, as well as the PT-symmetric variant of the model

    Epidemiology, patterns of care, and mortality for patients with acute respiratory distress syndrome in intensive care units in 50 countries

    Get PDF
    IMPORTANCE: Limited information exists about the epidemiology, recognition, management, and outcomes of patients with the acute respiratory distress syndrome (ARDS). OBJECTIVES: To evaluate intensive care unit (ICU) incidence and outcome of ARDS and to assess clinician recognition, ventilation management, and use of adjuncts-for example prone positioning-in routine clinical practice for patients fulfilling the ARDS Berlin Definition. DESIGN, SETTING, AND PARTICIPANTS:The Large Observational Study to Understand the Global Impact of Severe Acute Respiratory Failure (LUNG SAFE) was an international, multicenter, prospective cohort study of patients undergoing invasive or noninvasive ventilation, conducted during 4 consecutive weeks in the winter of 2014 in a convenience sample of 459 ICUs from 50 countries across 5 continents. EXPOSURES:Acute respiratory distress syndrome. MAIN OUTCOMES AND MEASURES: The primary outcome was ICU incidence of ARDS. Secondary outcomes included assessment of clinician recognition of ARDS, the application of ventilatory management, the use of adjunctive interventions in routine clinical practice, and clinical outcomes from ARDS. RESULTS: Of 29,144 patients admitted to participating ICUs, 3022 (10.4%) fulfilled ARDS criteria. Of these, 2377 patients developed ARDS in the first 48 hours and whose respiratory failure was managed with invasive mechanical ventilation. The period prevalence of mild ARDS was 30.0% (95% CI, 28.2%-31.9%); of moderate ARDS, 46.6% (95% CI, 44.5%-48.6%); and of severe ARDS, 23.4% (95% CI, 21.7%-25.2%). ARDS represented 0.42 cases per ICU bed over 4 weeks and represented 10.4% (95% CI, 10.0%-10.7%) of ICU admissions and 23.4% of patients requiring mechanical ventilation. Clinical recognition of ARDS ranged from 51.3% (95% CI, 47.5%-55.0%) in mild to 78.5% (95% CI, 74.8%-81.8%) in severe ARDS. Less than two-thirds of patients with ARDS received a tidal volume 8 of mL/kg or less of predicted body weight. Plateau pressure was measured in 40.1% (95% CI, 38.2-42.1), whereas 82.6% (95% CI, 81.0%-84.1%) received a positive end-expository pressure (PEEP) of less than 12 cm H2O. Prone positioning was used in 16.3% (95% CI, 13.7%-19.2%) of patients with severe ARDS. Clinician recognition of ARDS was associated with higher PEEP, greater use of neuromuscular blockade, and prone positioning. Hospital mortality was 34.9% (95% CI, 31.4%-38.5%) for those with mild, 40.3% (95% CI, 37.4%-43.3%) for those with moderate, and 46.1% (95% CI, 41.9%-50.4%) for those with severe ARDS. CONCLUSIONS AND RELEVANCE: Among ICUs in 50 countries, the period prevalence of ARDS was 10.4% of ICU admissions. This syndrome appeared to be underrecognized and undertreated and associated with a high mortality rate. These findings indicate the potential for improvement in the management of patients with ARDS

    Measurement of CNGS muon neutrino speed with Borexino

    Get PDF
    We have measured the speed of muon neutrinos with the Borexino detector using short-bunch CNGS beams. The final result for the difference in time-of-flight between a =17 GeV muon neutrino and a particle moving at the speed of light in vacuum is {\delta}t = 0.8 \pm 0.7stat \pm 2.9sys ns, well consistent with zero.Comment: 6 pages, 5 figure

    J-PLUS: Tools to identify compact planetary nebulae in the Javalambre and southern photometric local universe surveys

    Get PDF
    From the approximately \sim3,500 planetary nebulae (PNe) discovered in our Galaxy, only 14 are known to be members of the Galactic halo. Nevertheless, a systematic search for halo PNe has never been performed. In this study, we present new photometric diagnostic tools to identify compact PNe in the Galactic halo by making use of the novel 12-filter system projects, J-PLUS (Javalambre Photometric Local Universe Survey) and S-PLUS (Southern-Photometric Local Universe Survey). We reconstructed the IPHAS (Isaac Newton Telescope (INT) Photometric Hα{\alpha} Survey of the Northern Galactic Plane) diagnostic diagram and propose four new ones using i) the J-PLUS and S-PLUS synthetic photometry for a grid of photo-ionisation models of halo PNe, ii) several observed halo PNe, as well as iii) a number of other emission-line objects that resemble PNe. All colour-colour diagnostic diagrams are validated using two known halo PNe observed by J-PLUS during the scientific verification phase and the first data release (DR1) of S-PLUS and the DR1 of J-PLUS. By applying our criteria to the DR1s (\sim1,190 deg2^2), we identified one PN candidate. However, optical follow-up spectroscopy proved it to be a H II region belonging to the UGC 5272 galaxy. Here, we also discuss the PN and two H II galaxies recovered by these selection criteria. Finally, the cross-matching with the most updated PNe catalogue (HASH) helped us to highlight the potential of these surveys, since we recover all the known PNe in the observed area. The tools here proposed to identify PNe and separate them from their emission-line contaminants proved to be very efficient thanks to the combination of many colours, even when applied -like in the present work- to an automatic photometric search that is limited to compact PNe
    corecore