Preliminary search for a νirus in Dacus oleae Gmel. populations in Northern Greece

Στην περίοδο από Ιούλιο έως Δεκέμβριο 1984 συλλέχΟησαν 4.5 g ακμαίων, 8.5 g υγιών προνυμφών και 0.45 g νεκρών προνυμφών του εντόμου Dacus oleae Gmel. από περιοχές της Βόρειας Ελλάδας, που χαρακτηρίζονταν από Βαριά προσβολή των ελαιοδένδρων από δάκο, στα οποία δεν εφαρμόστηκε χημική καταπολέμηση. Τα δείγματα εξετάσθηκαν για εγκλεισμένους και μη εγκλεισμένους ιούς με τη χρησιμοποίηση φυγοκεντρήσεων, οπτικού και ηλεκτρονικού μικροσκοπίου, ανάλυσης νουκλεϊ νικών οξέων KUI πειράματα μολυσματικότητας. Στα δείγματα των νεκρών προνυμφών, και σε αντίθεση με εκείνα των υγιών προνυμφών και των ακμαίων, εντοπίσθηκαν και απομονώθηκαν ιόμορφα σωμάτια. Τα σωμάτια αυτά είχαν διάμετρο περίπου 35 nm και μερικά ήταν άδεια, όπως φάνηκε από τη διείσδυση της χρωστικής κατά την αρνητική χρώση. Δεν κατέστη δυνατός ο παραπέρα χαρακτηρισμός των «ιοσωματίων» για το λόγο έλλειψης αρκετής ποσότητας δείγματος, ενώ προσπάθειες πολλαπλασιασμούτους σε προνύμφες του λεπιδόπτερου Galleria mellonella και σε καλλιέργειες κυττάρων Drosophila melanogastcr αποδείχθησαν ανεπιτυχείς. Αν και τα μικρά ιόμορφα σωμάτια ήταν το μοναδικό πιθανό παθογόνο αίτιο που αναγνωρίστηκε στις νεκρές προνύμφες, φαίνεται κάπως απίθανο να αποτελούν και το μοναδικό αίτιο του θανάτου για το λόγο του σχετικά μικρού αριθμού τους. Πάντως αν καταστεί δυνατό να πολλαπλασιασθούν οι «ιοί» αυτοί σε εκτροφές του δάκου της ελιάς ή σε καλλιέργειες κυττάρων ιστών του ίδιου εντόμου, ίσως να αποτελέσουν στο μέλλον ένα βιολογικό μέσο καταπολέμησης του.A large number of larvae of Dacus oleae were collected from infested olives in Northern Greece, and a small proportion of these were found to be dead. Adult flies were caught in McPhail traps at the same locations. The larvae and adults were fractionated by a series of steps designed to identify occluded and nonoccluded viruses. Virus-like particles were identified in small amounts only in the dead larvae

Phase transitions in a network with range dependent connection probability

We consider a one-dimensional network in which the nodes at Euclidean distance $l$ can have long range connections with a probabilty $P(l) \sim l^{-\delta}$ in addition to nearest neighbour connections. This system has been shown to exhibit small world behaviour for $\delta < 2$ above which its behaviour is like a regular lattice. From the study of the clustering coefficients, we show that there is a transition to a random network at $\delta = 1$. The finite size scaling analysis of the clustering coefficients obtained from numerical simulations indicate that a continuous phase transition occurs at this point. Using these results, we find that the two transitions occurring in this network can be detected in any dimension by the behaviour of a single quantity, the average bond length. The phase transitions in all dimensions are non-trivial in nature.Comment: 4 pages, revtex4, submitted to Physical Review

Multiscale studies of the three-dimensional dayside X-line

AbstractWe review recent experience from the Cluster, Double Star, and THEMIS missions for lessons that apply to the upcoming Magnetospheric Multiscale Mission (MMS) being developed for launch in 2014. On global scales, simulation and statistical studies lead to mean configurations of dayside reconnection, implying specific relative alignments of the inflow magnetic fields and X-line, with implications for MMS operations designed to maximize the number of close encounters with the diffusion region. At intermediate MHD-to-ion scales, reconstruction of features created by one or two X-lines have developed to the point where data from a cluster of spacecraft can determine their temporal trends and the approximate three-dimensional X-line structure. Recent petascale particle-in-cell (PIC) simulations of reconnection encompass three spatial dimensions with excellent resolution, and make striking predictions of electron scale physics that creates complex interacting flux ropes under component reconnection. High time resolution measurements from MMS will determine the detailed electron scale kinetics embedded within the global and MHD–ion scale contexts. These developments will lead to the refinement of our three-dimensional multiscale picture of reconnection, yielding improved understanding of the global, MHD, and local physics controlling the onset or quenching, variability, and mean rate of reconnection. This in turn will enable improved predictability of the structural features created by transient reconnection, and their space weather consequences

Perspective piece: What is a hotspot anyway?

The importance of spatial clusters, or "hotspots," in infectious disease epidemiology has been increasingly recognized, and targeting hotspots is often seen as an important component of disease-control strategies. However, the precise meaning of "hotspot" varies widely in current research and policy documents. Hotspots have been variously described as areas of elevated incidence or prevalence, higher transmission efficiency or risk, or higher probability of disease emergence. This ambiguity has led to confusion and may result in mistaken inferences regarding the best way to target interventions. We surveyed the literature on epidemiologic hotspots, examining the multitude of ways in which the term is used; and highlight the difference in the geographic scale of hotspots and the properties they are supposed to have. In response to the diversity in the term's usage, we advocate the use of more precise terms, such as "burden hotspot," "transmission hotspot," and "emergence hotspot," as well as explicit specification of the spatiotemporal scale of interest. Increased precision in terminology is needed to ensure clear and effective policies for disease control

A Way to Reopen the Window for Electroweak Baryogenesis

We reanalyse the sphaleron bound of electroweak baryogenesis when allowing deviations to the Friedmann equation. These modifications are well motivated in the context of brane cosmology where they appear without being in conflict with major experimental constraints on four-dimensional gravity. While suppressed at the time of nucleosynthesis, these corrections can dominate at the time of the electroweak phase transition and in certain cases provide the amount of expansion needed to freeze out the baryon asymmetry without requiring a strongly first order phase transition. The sphaleron bound is substantially weakened and can even disappear so that the constraints on the higgs and stop masses do not apply anymore. Such modification of cosmology at early times therefore reopens the parameter space allowing electroweak baryogenesis which had been reduced substantially given the new bound on the higgs mass imposed by LEP. In contrast with previous attempts to turn around the sphaleron bound using alternative cosmologies, we are still considering that the electroweak phase transition takes place in a radiation dominated universe. The universe is expanding fast because of the modification of the Friedmann equation itself without the need for a scalar field and therefore evading the problem of the decay of this scalar field after the completion of the phase transition and the risk that its release of entropy dilutes the baryon asymmetry produced at the transition.Comment: 19 pages, 3 figures; v2: minor changes, remark added at end of section 5 and in caption of figure 1; v3: references added, version to be publishe

PAX6, brain structure and function in human adults: Advanced MRI in aniridia

Objective PAX6 is a pleiotropic transcription factor essential for the development of several tissues including the eyes, central nervous system, and some endocrine glands. Recently it has also been shown to be important for the maintenance and functioning of corneal and pancreatic tissues in adults. We hypothesized that PAX6 is important for the maintenance of brain integrity in humans, and that adult heterozygotes may have abnormalities of cortical patterning analogous to those found in mouse models. Methods We used advanced magnetic resonance imaging techniques, including surface-based morphometry and region-of-interest analysis in adult humans heterozygously mutated for PAX6 mutations (n = 19 subjects and n = 21 controls). Using immunohistochemistry, we also studied PAX6 expression in the adult brain tissue of healthy subjects (n = 4) and patients with epilepsy (n = 42), some of whom had focal injuries due to intracranial electrode track placement (n = 17). Results There were significant reductions in frontoparietal cortical area after correcting for age and intracranial volume. A greater decline in thickness of the frontoparietal cortex with age, in subjects with PAX6 mutations compared to controls, correlated with age-corrected, accelerated decline in working memory. These results also demonstrate genotypic effects: those subjects with the most severe genotypes have the most widespread differences compared with controls. We also demonstrated significant increases in PAX6-expressing cells in response to acute injury in the adult human brain. Interpretation These findings suggest a role for PAX6 in the maintenance and consequent functioning of the adult brain, homologous to that found in other tissues. This has significant implications for the understanding and treatment of neurodegenerative diseases

Loop-Generated Bounds on Changes to the Graviton Dispersion Relation

We identify the effective theory appropriate to the propagation of massless bulk fields in brane-world scenarios, to show that the dominant low-energy effect of asymmetric warping in the bulk is to modify the dispersion relation of the effective 4-dimensional modes. We show how such changes to the graviton dispersion relation may be bounded through the effects they imply, through loops, for the propagation of standard model particles. We compute these bounds and show that they provide, in some cases, the strongest constraints on nonstandard gravitational dispersions. The bounds obtained in this way are the strongest for the fewest extra dimensions and when the extra-dimensional Planck mass is the smallest. Although the best bounds come for warped 5-D scenarios, for which the 5D Planck Mass is O(TeV), even in 4 dimensions the graviton loop can lead to a bound on the graviton speed which is comparable with other constraints.Comment: 18 pages, LaTeX, 4 figures, uses revte

Snacking characteristics and patterns and their associations with diet quality and BMI in the Childhood Obesity Prevention and Treatment Research Consortium

Objective: To describe snacking characteristics and patterns in children and examine associations with diet quality and BMI. Design: Children's weight and height were measured. Participants/adult proxies completed multiple 24 h dietary recalls. Snack occasions were self-identified. Snack patterns were derived for each sample using exploratory factor analysis. Associations of snacking characteristics and patterns with Healthy Eating Index-2010 (HEI-2010) score and BMI were examined using multivariable linear regression models. Setting: Childhood Obesity Prevention and Treatment Research (COPTR) Consortium, USA: NET-Works, GROW, GOALS and IMPACT studies. Participants: Predominantly low-income, racial/ethnic minorities: NET-Works (n 534, 2-4-year-olds); GROW (n 610, 3-5-year-olds); GOALS (n 241, 7-11-year-olds); IMPACT (n 360, 10-13-year-olds).Results: Two snack patterns were derived for three studies: a meal-like pattern and a beverage pattern. The IMPACT study had a similar meal-like pattern and a dairy/grains pattern. A positive association was observed between meal-like pattern adherence and HEI-2010 score (P for trend < 0-01) and snack occasion frequency and HEI-2010 score (β coefficient (95 % CI): NET-Works, 0-14 (0-04, 0-23); GROW, 0-12 (0-02, 0-21)) among younger children. A preference for snacking while using a screen was inversely associated with HEI-2010 score in all studies except IMPACT (β coefficient (95 % CI): NET-Works, -3-15 (-5-37, -0-92); GROW, -2-44 (-4-27, -0-61); GOALS, -5-80 (-8-74, -2-86)). Associations with BMI were almost all null. Conclusions: Meal-like and beverage patterns described most children's snack intake, although patterns for non-Hispanic Blacks or adolescents may differ. Diets of 2-5-year-olds may benefit from frequent meal-like pattern snack consumption and diets of all children may benefit from decreasing screen use during eating occasions

Multicritical microscopic spectral correlators of hermitian and complex matrices

We find the microscopic spectral densities and the spectral correlators associated with multicritical behavior for both hermitian and complex matrix ensembles, and show their universality. We conjecture that microscopic spectral densities of Dirac operators in certain theories without spontaneous chiral symmetry breaking may belong to these new universality classes