Understory influence on leafroller pupunations in Hawke's bay organic apple orchard

Leafrollers (Tortricidae) were collected from apple foliage and understorey vegetation in six commercial organic apple orchards in Hawke’s Bay over one season. Assessments were made of plant species present in the understorey at the time of collection. All leafroller larvae were reared to adults on artificial diet to identify leafroller species and parasitoids. Nearly half (47%) of all leafrollers collected in these orchards were located in the understorey, highlighting the importance of understorey and its management for the control of leafroller. Dock, clover and dandeliontype plants contributed 25% to the overall understorey, yet hosted 75% of the leafrollers collected from the understorey. Dolichogenidea sp. was the most abundant parasitoid (79%) attacking leafrollers found amongst the apple foliage, whereas Glyptapanteles demeter was dominant in the understorey (61%). Generally the number of leafrollers in an orchard was proportional to the abundance of broadleaf weeds and inversely proportional to parasitis

Event-related potentials in autistic and healthy children on an auditory choice reaction time task

Introduction: Childhood autism can occur in 5 out of 10,000 of the population. The condition covers problems of sensory modulation, comprehension and communication as it relates to both objects and people. Of the stages of information processing recorded in auditory event-related potentials (ERPs), reductions of N1 and P3 amplitude have been reported in many situations, but an increased P3 response to non-targets may represent difficulties in attributing differentially significance to some but not all stimuli.. Methods: Recordings were derived from midline and 4 lateral sites on the scalp of 7 children with autism and 7/13 healthy control children matched for age (median 139 vs. 135 months). A three-tone oddball paradigm was presented in a passive and active-task form (72% at 1 kHz, 14% at 0.5 kHz and 14% at 2.0 kHz) Results: a) Autistic subjects showed twice as many errors of omission and a higher beta criterion (signal detection) for targets. b) For autistic subjects N1 latencies were shorter and N1 amplitude larger to deviants (especially nontargets). c) However, subtraction of the ERPs in nontarget from target conditions showed that the processing negativity (PN) and especially the Negative difference (Nd) was smaller in autistic subjects. d) In contrast the P3 amplitude (especially after the target) was smaller in autistic subjects. e) Within autistic subjects the topography showed more early negativity after deviants at left frontal sites and more target induced late positivity at right parietal sites. Conclusions: The ERPs of autistic children were more responsive to stimulus features (high frequency or deviance) and less responsive to the stimulus associations (target features). The ERPs also provide conflicting signs of neurodevelopment, -- precocious in the right-hemispheric emphasis for P3, but delayed in that P3 was not maximal at parietal sites

Event-related potentials and monoamines in autistic children on a clinical trial of fenfluramine

Introduction: As autistic persons have problems with selecting and encoding meaningful stimuli and multi-centre studies (Ritvo et al., 1983, 1986) had reported mild behavioural improvements following treatment with fenfluramine, event-related potential (ERP) stages of information processing were studied in childhood autism as part of a double blind crossover study of the efficacy of dl fenfluramine. . Methods: Acceptable recordings were derived from midline and 4 lateral sites on the scalp of 7 from 14 young persons with autism who understood the task (6 male, 1 female 5.8-17.7 years-of-age). A three-tone oddball paradigm was presented in a passive and active-task form (72% at 1 kHz, 14% at 0.5 kHz and 14% at 2.0 kHz) under placebo and drug conditions (where each condition lasted 5 months). Eleven patients provided blood and urine samples for monoamine analyses in both conditions. Results: a) With fenfluramine treatment blood serotonin decreased and urinary catecholamine levels fell (25-45%, but dopamine utilization (HVA/DA) increased 2-4-fold. b) Under fenfluramine autistic subjects responded non-significantly faster, with fewer errors of omission and improved /decreased beta criterion (signal detection). [IQ measures increased 7.5 points.] c) N1 amplitudes (Fz) decreased and latencies increased in the fenfluramine condition. Early negativity (especially on the right) correlated inversely with HVA/DA actvivity. Subtraction of the ERPs in nontarget from target conditions showed that the Negative difference (Nd) increased during fenfluramine treatment. d) P3 amplitudes (especially after the deviants) increased with fenfluramine treatment. But in the difference waveform (active-minus-passive condition) the P3 amplitude was halved. The distribution of the P3 component moved rostrally with treatment. Conclusions: N1 and P3 components of the ERP were responsive to fenfluramine treament. Treatment appears to have mildly improved early stimulus processing at stages represented by the early negative components, but to have mildly impaired processing at the P3-stage. The N1 / Nd - related improvement seems to be related to increased dopamine activity (cf. neuroleptic-like properties of racemate fenfluramine)

Fatty acid profile of plasma NEFA does not reflect adipose tissue fatty acid profile

Adipose tissue (AT) fatty acid (FA) composition partly reflects habitual dietary intake. Circulating NEFA are mobilised from AT and might act as a minimally invasive surrogate marker of AT FA profile. Agreement between twenty-eight FA in AT and plasma NEFA was assessed using concordance coefficients in 204 male and female participants in a 12-month intervention using supplements to increase the intake of EPA and DHA. Concordance coefficients generally showed very poor agreement between AT FA and plasma NEFA at baseline SFA: 0·07; MUFA: 0·03; n-6 PUFA: 0·28; n-3 PUFA: 0·01). Participants were randomly divided into training (70 %) and validation (30 %) data sets, and models to predict AT and dietary FA were fitted using data from the training set, and their predictive ability was assessed using data from the validation set. AT n-6 PUFA and SFA were predicted from plasma NEFA with moderate accuracy (mean absolute percentage error n-6 PUFA: 11 % and SFA: 8 %), but predicted values were unable to distinguish between low, medium and high FA values, with only 25 % of n-6 PUFA and 33 % of SFA predicted values correctly assigned to the appropriate tertile group. Despite an association between AT and plasma NEFA EPA (P=0·001) and DHA (P=0·01) at baseline, there was no association after the intervention. To conclude, plasma NEFA are not a suitable surrogate for AT F

Oscillations of a solid sphere falling through a wormlike micellar fluid

We present an experimental study of the motion of a solid sphere falling through a wormlike micellar fluid. While smaller or lighter spheres quickly reach a terminal velocity, larger or heavier spheres are found to oscillate in the direction of their falling motion. The onset of this instability correlates with a critical value of the velocity gradient scale $\Gamma_{c}\sim 1$ s$^{-1}$. We relate this condition to the known complex rheology of wormlike micellar fluids, and suggest that the unsteady motion of the sphere is caused by the formation and breaking of flow-induced structures.Comment: 4 pages, 4 figure

Electron transport in the dye sensitized nanocrystalline cell

Dye sensitised nanocrystalline solar cells (Gr\"{a}tzel cells) have achieved solar-to-electrical energy conversion efficiencies of 12% in diffuse daylight. The cell is based on a thin film of dye-sensitised nanocrystalline TiO$_2$ interpenetrated by a redox electrolyte. The high surface area of the TiO$_2$ and the spectral characteristics of the dye allow the device to harvest 46% of the solar energy flux. One of the puzzling features of dye-sensitised nano-crystalline solar cells is the slow electron transport in the titanium dioxide phase. The available experimental evidence as well as theoretical considerations suggest that the driving force for electron collection at the substrate contact arises primarily from the concentration gradient, ie the contribution of drift is negligible. The transport of electrons has been characterised by small amplitude pulse or intensity modulated illumination. Here, we show how the transport of electrons in the Gr\"{a}tzel cell can be described quantitatively using trap distributions obtained from a novel charge extraction method with a one-dimensional model based on solving the continuity equation for the electron density. For the first time in such a model, a back reaction with the I$_3^-$ ions in the electrolyte that is second order in the electron density has been included.Comment: 6 pages, 5 figures, invited talk at the workshop 'Nanostructures in Photovoltaics' to appear in Physica

A controlled crossover trial of fendluramine in autism

Introduction: Against a background of variable results achieved by the treatment of childhood autism with dopaminergic agonists or antagonists, and opiate antagonists and mild behavioural improvements achieved following treatment with fenfluramine (Geller et al., 1982; Ritvo et al., 1984 among others) a 12 month double-blind crossover trial of fenfluramine was undertaken. [the d-isomer releases serotonin, the l-isomer modestly blocks dopamine receptors.] Methods: Six female and 14 male children and adolescents with autism were enrolled (median 9y; range 5-17 years of age) in a trial run over a 1 month baseline, 5 months of treatment, 2 months placebo, and 5 months of treatment. Parent diaries were kept. Various tests and rating scales for development, verbal and noverbal abilities along with measures of blood serotonin, urinary catecholamines and auditory event-related potentials (ERPs) were measured at 6-month intervals. Results: a) With fenfluramine treatment children lost weight, blood serotonin decreased by 60% and urinary catecholamine levels fell (25-45%, but dopamine utilization (HVA/DA) increased 2-4-fold. b) Under fenfluramine some autistic subjects improved on measures of cognitive and language function. Two mute subjects began to speak, but for the group overall the improvements did not prove significant. [British Ability Scale, Reynell developmental language and Vineland social maturity scale improvements were significant.] c) Treatment improved early stages of information processing, but impaired later stages as measured in the ERP (i.e. early negative going excitatory vs. later positive going inhibitory response, respectively in 7 patients). The early negativity changes (especially over the right hemisphere) correlated inversely with HVA/DA actvivity. d) Side effects reported included lethargy and irritability.. Conclusions: While individuals showed marked reductions of stereotypies, hyperactivity, and improvements on develepmental and cognitive measures, the absence of clear group-wide effects suggests that fenfluramine would have but a limited place in the management of some patients with autism

The Supernova Relic Neutrino Background

An upper bound to the supernova relic neutrino background from all past Type II supernovae is obtained using observations of the Universal metal enrichment history. We show that an unambiguous detection of these relic neutrinos by the Super-Kamiokande detector is unlikely. We also analyze the event rate in the Sudbury Neutrino Observatory (where coincident neutrons from anti-nu_e + D --> n + n + e+ might enhance background rejection), and arrive at the same conclusion. If the relic neutrino flux should be observed to exceed our upper bound and if the observations of the metal enrichment history (for z<1) are not in considerable error, then either the Type II supernova rate does not track the metal enrichment history or some mechanism may be responsible for transforming anti-nu_{mu,tau} --> anti-nu_e.Comment: Matches version accepted for publication in Phys. Rev.

Structure factor of polymers interacting via a short range repulsive potential: application to hairy wormlike micelles

We use the Random Phase Approximation (RPA) to compute the structure factor, S(q), of a solution of chains interacting through a soft and short range repulsive potential V. Above a threshold polymer concentration, whose magnitude is essentially controlled by the range of the potential, S(q) exhibits a peak whose position depends on the concentration. We take advantage of the close analogy between polymers and wormlike micelles and apply our model, using a Gaussian function for V, to quantitatively analyze experimental small angle neutron scattering profiles of semi-dilute solutions of hairy wormlike micelles. These samples, which consist in surfactant self-assembled flexible cylinders decorated by amphiphilic copolymer, provide indeed an appropriate experimental model system to study the structure of sterically interacting polymer solutions