Picosecond photophysical processes in iodoanthracenes

Picosecond photophysical processes in 2- and 9-iodoanthracene in cyclohexane at room temperature were studied by triplet-triplet transient absorption spectroscopy between 420-500 nanometers. For small amounts of excess vibronic energy in S(,1), intersystem crossing from the first excited singlet state into high triplet states T(,n) (n \u3e 1) with subsequent internal conversion to T(,1) or dissociation from the upper triplet manifold is suggested as a primary pathway for nonradiative relaxation. Rate constants for the processes were estimated using the results from previous fluorescence studies and the population risetime data for T(,1). Analyses of the photoproducts generated by excitation at two different wavelengths into the first excited singlet state reveal a vibronic level dependence of the photodissociation yield, indicating that photodissociation can proceed via at least two different mechanisms in the iodoanthracenes;Stimulated Raman processes and self-action effects are shownto be primarily responsible for the generation of a picosecondcontinuum when 532 nm picosecond pulses are focused into aCCl(,4) continuum cell. An experimental assessment of the artifactsintroduced by the angular distribution of continuum light on the;triplet-triplet absorption spectra of acridine is given and proceduresto minimize these effects are suggested; (\u271)DOE Report IS-T-1042. This work was performed under contract number W-7405-Eng-82 with the U.S. Department of Energy

Petunia Performance Under Application of Animal-Based Protein Hydrolysates: Effects on Visual Quality, Biomass, Nutrient Content, Root Morphology, and Gas Exchange

Sustainable plant production practices have been implemented to reduce the use of synthetic fertilizers and other agrochemicals. One way to reduce fertilizer use without negatively impacting plant nutrition is to enhance crop uptake of nutrients with biostimulants. As the effectiveness of a biostimulant can depend on the origin, species, dose, and application method, the aim of this research was to evaluate the effect of a commercial animal-based protein hydrolysate (PH) biostimulant on the visual quality, biomass, macronutrient content, root morphology, and leaf gas exchange of a petunia (Petunia × hybrida Hort. “red”) under preharvest conditions. Two treatments were compared: (a) three doses of an animal-based PH biostimulant: 0 (D0 = control), 0.1 (D0.1 = normal), and 0.2 g L–1 (D0.2 = high); (b) two biostimulant application methods: foliar spray and root drenching. The dose × method interaction effect of PH biostimulant on the plants was significant in terms of quality grade and fresh and dry biomass. The high dose applied as foliar spray produced petunias with extra-grade visual quality (number of flowers per plant 161, number of leaves per plant 450, and leaf area per plant 1,487 cm2) and a total aboveground dry weight of 35 g, shoots (+91%), flowers (+230%), and leaf fresh weight (+71%). P and K contents were higher than in untreated petunias, when plants were grown with D0.2 and foliar spray. With foliar spray at the two doses, SPAD showed a linear increase (+21.6 and +41.0%) with respect to untreated plants. The dose × method interaction effect of biostimulant application was significant for root length, projected and total root surface area, and number of root tips, forks, and crossings. Concerning leaf gas exchange parameters, applying the biostimulant at both doses as foliar spray resulted in a significant improvement in net photosynthesis (D0.1: 22.9 μmol CO2 m–2 s–1 and D0.2: 22.4 μmol CO2 m–2 s–1) and stomatal conductance (D0.1: 0.42 mmol H2O m–2 s–1 and D0.2: 0.39 mmol H2O m–2 s–1) compared to control. These results indicate that application of PH biostimulant at 0.2 g L–1 as foliar spray helped to achieve extra-grade plants and that this practice can be exploited in sustainable greenhouse conditions for commercial production of petunia

The bispectrum of redshifted 21-cm fluctuations from the dark ages

Brightness-temperature fluctuations in the redshifted 21-cm background from the cosmic dark ages are generated by irregularities in the gas-density distribution and can then be used to determine the statistical properties of density fluctuations in the early Universe. We first derive the most general expansion of brightness-temperature fluctuations up to second order in terms of all the possible sources of spatial fluctuations. We then focus on the three-point statistics and compute the angular bispectrum of brightness-temperature fluctuations generated prior to the epoch of hydrogen reionization. For simplicity, we neglect redshift-space distortions. We find that low-frequency radio experiments with arcmin angular resolution can easily detect non-Gaussianity produced by non-linear gravity with high signal-to-noise ratio. The bispectrum thus provides a unique test of the gravitational instability scenario for structure formation, and can be used to measure the cosmological parameters. Detecting the signature of primordial non-Gaussianity produced during or right after an inflationary period is more challenging but still possible. An ideal experiment limited by cosmic variance only and with an angular resolution of a few arcsec has the potential to detect primordial non-Gaussianity with a non-linearity parameter of f_NL ~ 1. Additional sources of error as weak lensing and an imperfect foreground subtraction could severely hamper the detection of primordial non-Gaussianity which will benefit from the use of optimal estimators combined with tomographic techniques.Comment: 15 pages, 4 figures, revised version accepted for publication in ApJ (contains an improved discussion of gas temperature fluctuations

Resistant arterial hypertension in a patient with adrenal incidentaloma multiple steno-obstructive vascular lesions and antiphospholipid syndrome

Resistant hypertension is defined as above of blood pressure (≤ 140/90 mmHg) despite therapy with three or more antihypertensive drugs of different classes at maximum tolerable doses with one bling a diuretic. An important consideration in defining a patient with resistant hypertension is the mislabeling of secondary hypertension as resistant hypertension. Here, we report a patients with resistant hypertension caused by multiple stenoocclusive arteries due to antiphospholipid syndrome and coexisting with subclinical Cushing’s syndrome

Ethics and Design in the Brazilian Context

Often driven by practical and immediate requirements, more and more people are incorporating technology into a variety of aspects of their lives, often without reflecting on the consequences of using them. On the other hand, studies on interactive system development that lead to behavioral change have been gaining ground on the agenda of large HCI conferences. This movement brings to the forefront the fundamental issues of ethics in design and technology use. A designer’s intentions, when directing certain actions or behaviors, are not always explicit or desired by the stakeholders affected by the use of the technology. Systems that induce an undesired purchase, or even those that use conditioning strategies to cause a behavioral change are examples of such intentions. The challenge proposed is therefore about the relationship between design and personal freedom in a way that these technology users do not become victims, either passively or submissively, of the effects of its use. This advance allows for the redefinition of the relationship between man and technology, and the application of new forms of designing and developing interactive systems that take into account the ethical aspects of this relationship