Polarization and energy dynamics in ultrafocused optical Kerr propagation

Developing a complete vectorial description of optical nonparaxial propagation of highly focused beams in Kerr media, we disclose a family of new phenomena. These phenomena appear to emerge as a consequence of the mutual coupling of all three components of the optical field. This circumstance, which is intrinsic to the very nature of Kerr propagation, was previously discarded on the basis of the conjecture that a reduced system is possible in which only one transverse field component interacts with the longitudinal component

Bioactivity of the Andean aromatic plants Aloysia citriodora and Bursera graveolens essential oils against the blowfly Calliphora vomitoria

Tropical Andes is a biodiversity hot spot rich in aromatic plant species, whose potential as a source of active compounds for insect pests’ control is still largely underexploited. Here, the Essential Oils (EOs) extracted from two Ecuadorian plants, the shrub Aloysia citriodora (Verbenaceae) and the tree Bursera graveolens (Burseraceae), were chemically analysed and tested for their bioactivity against the blue blowfly Calliphora vomitoria (Linnaeus, 1758) (Diptera: Calliphoridae). This fly is a vector of pathogenic microorganisms, dangerous in factories and stores where fresh meat is processed, stored, and sold. The main components of the A. citriodora EO are geranial and limonene, while in the B. graveolens EO they are limonene and α-terpineol. The effects of the two EOs were evaluated against C. vomitoria by a behavioural assay in a two-choice olfactometer (concentrations range 0.07-2.8 μL L-1 air). Besides, the insecticidal properties of the two EOs were tested by fumigation (EOs concentrations from 6.06 to 36.36 μL L-1 air), by contact with topical applications using a Burkard micro dispenser (EOs dose from 0.10 to 0.60 μl EO/fly), and by ingestion of a mucilage containing EOs (from 15 to 75 μl EO mL-1 mucilage), sucrose, and agarose. Furthermore, the ovicidal activity was assessed (concentrations from 0.006 to 0.075 μL EO cm-2 of filter paper). The results of the behavioural assay showed a stronger repellent effect exerted by the A. citriodora EO, while all the toxicity tests revealed dose-dependent mortality of the blowflies and eggs

The Adiabatic Piston and the Second Law of Thermodynamics

A detailed analysis of the adiabatic-piston problem reveals peculiar dynamical features that challenge the general belief that isolated systems necessarily reach a static equilibrium state. In particular, the fact that the piston behaves like a perpetuum mobile, i.e., it never stops but keeps wandering, undergoing sizable oscillations, around the position corresponding to maximum entropy, has remarkable implications on the entropy variations of the system and on the validity of the second law when dealing with systems of mesoscopic dimensions.Comment: 6 pages, 4 figures, First International Conference on Quantum Limits to the Second La

Experimental measurement of photothermal effect in Fabry-Perot cavities

We report the experimental observation of the photothermal effect. The measurements are performed by modulating the laser power absorbed by the mirrors of two high-finesse Fabry-Perot cavities. The results are very well described by a recently proposed theoretical model [M. Cerdonio, L. Conti, A. Heidmann and M. Pinard, Phys. Rev. D 63 (2001) 082003], confirming the correctness of such calculations. Our observations and quantitative characterization of the photothermal effect demonstrate its critical importance for high sensitivity interferometric displacement measurements, as those necessary for gravitational wave detection.Comment: 4 pages, 3 figures, submitted to Phys. Rev. Let

Responses from olfactory sensilla of Sitophilus zeamais to Andean essential oils.

Lamiaceae species are well-known in traditional medicine. In the last years, Essential Oils (EOs) of many Lamiaceae have showed to be excellent repellents and/or insecticides. Tropical Andes are extremely rich in endemic flora, possible source of new bioactive substances. Here, we verified the insect repellent activity of the EOs extracted from Clinopodium tomentosum and C. nubigenum, two Lamiaceae typical of the Ecuadorian Andes. The two EOs were tested against the maize weevil Sitophilus zeamais (Motschulsky) (Coleoptera: Curculionidae), one of the most destructive pests of stored and processed cereals. To characterize the olfactory sensilla of S. zeamais, its antennal structure was investigated by scanning and transmission electron microscopy. The electrophysiological and behavioural responses of the insect to the EOs were then investigated by electroantennography and olfactometer trials. The morphological study revealed the presence of three types of sensilla (Basiconic Sensillum 1, 2, and Grooved Peg Sensillum), that could be involved in the perception of the EOs volatile compounds. Accordingly, the electroantennography showed a positive dose-dependent response of the insect antennae to both the EOs. The behavioural tests displayed a significative repellence of the EOs, starting from 8.4 μL L-1 air, and that the efficacy and readiness of the response to the stimulus was higher for C. tomentosum. In conclusion, both the EOs are detected by the insect by its antennae and exert a strong repellent effect. The results confirm that Andean flora represents a valuable source of unexploited bioactive substances that can be utilized as promising tools for foodstuff pests’ control

Dermatillomania: Strategies for developing protective biomaterials/cloth

Dermatillomania or skin picking disorder (SPD) is a chronic, recurrent, and treatment resistant neuropsychiatric disorder with an underestimated prevalence that has a concerning negative impact on an individual’s health and quality of life. The current treatment strategies focus on behavioral and pharmacological therapies that are not very effective. Thus, the primary objective of this review is to provide an introduction to SPD and discuss its current treatment strategies as well as to propose biomaterial-based physical barrier strategies as a supporting or alternative treatment. To this end, searches were conducted within the PubMed database and Google Scholar, and the results obtained were organized and presented as per the following categories: prevalence, etiology, conse-quences, diagnostic criteria, and treatment strategies. Furthermore, special attention was provided to alternative treatment strategies and biomaterial-based physical treatment strategies. A total of six products with the potential to be applied as physical barrier strategies in supporting SPD treatment were shortlisted and discussed. The results indicated that SPD is a complex, underestimated, and underemphasized neuropsychiatric disorder that needs heightened attention, especially with regard to its treatment and care. Moreover, the high synergistic potential of biomaterials and nanosystems in this area remains to be explored. Certain strategies that are already being utilized for wound healing can also be further exploited, particularly as far as the prevention of infections is concerned

Associated reading skills in children with a history of Specific Language Impairment (SLI)

A large cohort of 200 eleven-year-old children with Specific Language Impairment (SLI) were assessed on basic reading accuracy and on reading comprehension as well as language tasks. Reading skills were examined descriptively and in relation to early language and literacy factors. Using stepwise regression analyses in which age and nonverbal IQ were controlled for, it was found that a single word reading measure taken at 7 years was unsurprisingly a strong predictor of the two different types of reading ability. However, even with this measure included, a receptive syntax task (TROG) entered when reading accuracy score was the DV. Furthermore, a test of expressive syntax/narrative and a receptive syntax task completed at 7 years entered into the model for word reading accuracy. When early reading accuracy was excluded from the analyses, early phonological skills also entered as a predictor of both reading accuracy and comprehension at 11 years. The group of children with a history of SLI were then divided into those with no literacy difficulties at 11 and those with some persisting literacy impairment. Using stepwise logistic regression, and again controlling for IQ and age, 7 years receptive syntax score (but not tests of phonology, expressive vocabulary or expressive syntax/narrative) entered as a positive predictor of membership of the ‘no literacy problems’ group regardless of whether early reading accuracy was controlled for in step one. The findings are discussed in relation to the overlap of SLI and dyslexia and the long term sequelae of language impairment

Multiple hydrodynamical shocks induced by Raman effect in photonic crystal fibres

We theoretically predict the occurrence of multiple hydrodynamical-like shock phenomena in the propagation of ultrashort intense pulses in a suitably engineered photonic crystal fiber. The shocks are due to the Raman effect, which acts as a nonlocal term favoring their generation in the focusing regime. It is shown that the problem is mapped to shock formation in the presence of a slope and a gravity-like potential. The signature of multiple shocks in XFROG signals is unveiled

Infrared catastrophe and tunneling into strongly correlated electron systems: Exact solution of the x-ray edge limit for the 1D electron gas and 2D Hall fluid

In previous work we have proposed that the non-Fermi-liquid spectral properties in a variety of low-dimensional and strongly correlated electron systems are caused by the infrared catastrophe, and we used an exact functional integral representation for the interacting Green's function to map the tunneling problem onto the x-ray edge problem, plus corrections. The corrections are caused by the recoil of the tunneling particle, and, in systems where the method is applicable, are not expected to change the qualitative form of the tunneling density of states (DOS). Qualitatively correct results were obtained for the DOS of the 1D electron gas and 2D Hall fluid when the corrections to the x-ray edge limit were neglected and when the corresponding Nozieres-De Dominicis integral equations were solved by resummation of a divergent perturbation series. Here we reexamine the x-ray edge limit for these two models by solving these integral equations exactly, finding the expected modifications of the DOS exponent in the 1D case but finding no changes in the DOS of the 2D Hall fluid with short-range interaction. We also provide, for the first time, an exact solution of the Nozieres-De Dominicis equation for the 2D electron gas in the lowest Landau level.Comment: 6 pages, Revte

On the connection between the number of nodal domains on quantum graphs and the stability of graph partitions

Courant theorem provides an upper bound for the number of nodal domains of eigenfunctions of a wide class of Laplacian-type operators. In particular, it holds for generic eigenfunctions of quantum graph. The theorem stipulates that, after ordering the eigenvalues as a non decreasing sequence, the number of nodal domains $\nu_n$ of the $n$-th eigenfunction satisfies $n\ge \nu_n$. Here, we provide a new interpretation for the Courant nodal deficiency $d_n = n-\nu_n$ in the case of quantum graphs. It equals the Morse index --- at a critical point --- of an energy functional on a suitably defined space of graph partitions. Thus, the nodal deficiency assumes a previously unknown and profound meaning --- it is the number of unstable directions in the vicinity of the critical point corresponding to the $n$-th eigenfunction. To demonstrate this connection, the space of graph partitions and the energy functional are defined and the corresponding critical partitions are studied in detail.Comment: 22 pages, 6 figure