6,239 research outputs found
Ăvaluation de lâefficacitĂ© de lâinsecticide Tricel 480 EC comparĂ©e Ă la DeltamĂ©trine et Ă la CypermĂ©thrine contre les ravageurs du chou (Brassicacae L. sp.) en milieu paysan dans la rĂ©gion de Yamoussoukro en CĂŽte dâIvoire
Afin decontrĂŽler lâutilisation croissante et non raisonnĂ©e de produits phytosanitaires contre les ravageurs des cultures maraĂźchĂšres, 3 doses du TRIC 480 EC (0,8 L/ha, 1 L/ha et 2 L/ha), ont Ă©tĂ© testĂ©es. Il sâagit dedĂ©terminer la dose optimale dâutilisation pour la rĂ©duction efficiente des populations dâinsectes ravageurs du chou (Brassicacae L. sp.) comparĂ©e Ă celles de la DeltamĂ©thrine (12g/L) et du CypermĂ©trine (50g/L), deux formulations de rĂ©fĂ©rence utilisĂ©es contre les ravageurs du chou en milieu paysan et le tĂ©moin non traitĂ©. Un dispositif en Split-plot avec trois rĂ©pĂ©titions par objet a Ă©tĂ© utilisĂ©. Les ravageurs prĂ©dominants relevĂ©ssont les HomoptĂšres (pucerons), les OrthoptĂšres (sautĂ©riaux), les larves de LĂ©pidoptĂšres (Plutellaxylostella) et de DiptĂšres. Les 3 doses du TRIC 480 EC permettent de rĂ©duire de 80 %, les populations de pucerons etdonc les pertes par la dĂ©gĂ©nĂ©rescence des plants de chou. ContrĂŽle qui est significativement diffĂ©rent de la DeltamĂ©thrine (12g/L) et de la CypermĂ©thrine (50g/L) (P = 0,018 < 0,05). La dose de 0,8 L/ha de TRIC 480 EC contre les ravageurs du chou, avec une application hebdomadaire en pulvĂ©risation dĂšs le repiquage jusquâĂ une semaine avant les rĂ©coltes peut ĂȘtre recommandĂ©e aux paysans.Mots-clĂ©s : Chou (Brassicacae L. sp.), insectes ravageurs, TRIC 480 EC, CypermĂ©thrine 50 EC, DeltamĂ©thrine 12 EC, doses efficaces
Experimental Tests of General Relativity
Einstein's general theory of relativity is the standard theory of gravity,
especially where the needs of astronomy, astrophysics, cosmology and
fundamental physics are concerned. As such, this theory is used for many
practical purposes involving spacecraft navigation, geodesy, and time transfer.
Here I review the foundations of general relativity, discuss recent progress in
the tests of relativistic gravity in the solar system, and present motivations
for the new generation of high-accuracy gravitational experiments. I discuss
the advances in our understanding of fundamental physics that are anticipated
in the near future and evaluate the discovery potential of the recently
proposed gravitational experiments.Comment: revtex4, 30 pages, 10 figure
Hour-glass magnetic spectrum in an insulating, hole-doped antiferromagnet
Superconductivity in layered copper-oxide compounds emerges when charge
carriers are added to antiferromagnetically-ordered CuO2 layers. The carriers
destroy the antiferromagnetic order, but strong spin fluctuations persist
throughout the superconducting phase and are intimately linked to
super-conductivity. Neutron scattering measurements of spin fluctuations in
hole-doped copper oxides have revealed an unusual `hour-glass' feature in the
momentum-resolved magnetic spectrum, present in a wide range of superconducting
and non-superconducting materials. There is no widely-accepted explanation for
this feature. One possibility is that it derives from a pattern of alternating
spin and charge stripes, an idea supported by measurements on stripe-ordered
La1.875Ba0.125CuO4. However, many copper oxides without stripe order also
exhibit an hour-glass spectrum$. Here we report the observation of an
hour-glass magnetic spectrum in a hole-doped antiferromagnet from outside the
family of superconducting copper oxides. Our system has stripe correlations and
is an insulator, which means its magnetic dynamics can conclusively be ascribed
to stripes. The results provide compelling evidence that the hour-glass
spectrum in the copper-oxide superconductors arises from fluctuating stripes.Comment: 13 pages, 4 figures, to appear in Natur
Lipidomics Reveals Early Metabolic Changes in Subjects with Schizophrenia: Effects of Atypical Antipsychotics
There is a critical need for mapping early metabolic changes in schizophrenia to capture failures in regulation of biochemical pathways and networks. This information could provide valuable insights about disease mechanisms, trajectory of disease progression, and diagnostic biomarkers. We used a lipidomics platform to measure individual lipid species in 20 drug-naïve patients with a first episode of schizophrenia (FE group), 20 patients with chronic schizophrenia that had not adhered to prescribed medications (RE group), and 29 race-matched control subjects without schizophrenia. Lipid metabolic profiles were evaluated and compared between study groups and within groups before and after treatment with atypical antipsychotics, risperidone and aripiprazole. Finally, we mapped lipid profiles to n3 and n6 fatty acid synthesis pathways to elucidate which enzymes might be affected by disease and treatment. Compared to controls, the FE group showed significant down-regulation of several n3 polyunsaturated fatty acids (PUFAs), including 20:5n3, 22:5n3, and 22:6n3 within the phosphatidylcholine and phosphatidylethanolamine lipid classes. Differences between FE and controls were only observed in the n3 class PUFAs; no differences where noted in n6 class PUFAs. The RE group was not significantly different from controls, although some compositional differences within PUFAs were noted. Drug treatment was able to correct the aberrant PUFA levels noted in FE patients, but changes in re patients were not corrective. Treatment caused increases in both n3 and n6 class lipids. These results supported the hypothesis that phospholipid n3 fatty acid deficits are present early in the course of schizophrenia and tend not to persist throughout its course. These changes in lipid metabolism could indicate a metabolic vulnerability in patients with schizophrenia that occurs early in development of the disease. © 2013 McEvoy et al
Regional and cell-type-specific effects of DAMGO on striatal D1 and D2 dopamine receptor-expressing medium-sized spiny neurons
The striatum can be divided into the DLS (dorsolateral striatum) and the VMS (ventromedial striatum), which includes NAcC (nucleus accumbens core) and NAcS (nucleus accumbens shell). Here, we examined differences in electrophysiological properties of MSSNs (medium-sized spiny neurons) based on their location, expression of DA (dopamine) D1/D2 receptors and responses to the Ό-opioid receptor agonist, DAMGO {[D-Ala2-MePhe4-Gly(ol)5]enkephalin}. The main differences in morphological and biophysical membrane properties occurred among striatal sub-regions. MSSNs in the DLS were larger, had higher membrane capacitances and lower Rin (input resistances) compared with cells in the VMS. RMPs (resting membrane potentials) were similar among regions except for D2 cells in the NAcC, which displayed a significantly more depolarized RMP. In contrast, differences in frequency of spontaneous excitatory synaptic inputs were more prominent between cell types, with D2 cells receiving significantly more excitatory inputs than D1 cells, particularly in the VMS. Inhibitory inputs were not different between D1 and D2 cells. However, MSSNs in the VMS received more inhibitory inputs than those in the DLS. Acute application of DAMGO reduced the frequency of spontaneous excitatory and inhibitory postsynaptic currents, but the effect was greater in the VMS, in particular in the NAcS, where excitatory currents from D2 cells and inhibitory currents from D1 cells were inhibited by the largest amount. DAMGO also increased cellular excitability in the VMS, as shown by reduced threshold for evoking APs (action potentials). Together the present findings help elucidate the regional and cell-type-specific substrate of opioid actions in the striatum and point to the VMS as a critical mediator of DAMGO effects
Direct evidence for charge stripes in a layered cobalt oxide
Recent experiments indicate that static stripe-like charge order is generic to the hole-doped copper oxide superconductors and competes with superconductivity. Here we show that a similar type of charge order is present in La5/3 Sr1/3 CoO4 , an insulating analogue of the copper oxide superconductors containing cobalt in place of copper. The stripe phase we have detected is accompanied by short-range, quasi-one-dimensional, antiferromagnetic order, and provides a natural explanation for the distinctive hour- glass shape of the magnetic spectrum previously observed in neutron scattering mea- surements of La2âxSrx CoO4 and many hole-doped copper oxide superconductors. The results establish a solid empirical basis for theories of the hourglass spectrum built on short-range, quasi-static, stripe correlations
To dash or to dawdle: verb-associated speed of motion influences eye movements during spoken sentence comprehension
In describing motion events verbs of manner provide information about the speed of agents or objects in those events. We used eye tracking to investigate how inferences about this verb-associated speed of motion would influence the time course of attention to a visual scene that matched an event described in language. Eye movements were recorded as participants heard spoken sentences with verbs that implied a fast (âdashâ) or slow (âdawdleâ) movement of an agent towards a goal. These sentences were heard whilst participants concurrently looked at scenes depicting the agent and a path which led to the goal object. Our results indicate a mapping of events onto the visual scene consistent with participants mentally simulating the movement of the agent along the path towards the goal: when the verb implies a slow manner of motion, participants look more often and longer along the path to the goal; when the verb implies a fast manner of motion, participants tend to look earlier at the goal and less on the path. These results reveal that event comprehension in the presence of a visual world involves establishing and dynamically updating the locations of entities in response to linguistic descriptions of events
Kondo physics in carbon nanotubes
The connection of electrical leads to wire-like molecules is a logical step
in the development of molecular electronics, but also allows studies of
fundamental physics. For example, metallic carbon nanotubes are quantum wires
that have been found to act as one-dimensional quantum dots, Luttinger-liquids,
proximity-induced superconductors and ballistic and diffusive one-dimensional
metals. Here we report that electrically-contacted single-wall nanotubes can
serve as powerful probes of Kondo physics, demonstrating the universality of
the Kondo effect. Arising in the prototypical case from the interaction between
a localized impurity magnetic moment and delocalized electrons in a metallic
host, the Kondo effect has been used to explain enhanced low-temperature
scattering from magnetic impurities in metals, and also occurs in transport
through semiconductor quantum dots. The far higher tunability of dots (in our
case, nanotubes) compared with atomic impurities renders new classes of
Kondo-like effects accessible. Our nanotube devices differ from previous
systems in which Kondo effects have been observed, in that they are
one-dimensional quantum dots with three-dimensional metal (gold) reservoirs.
This allows us to observe Kondo resonances for very large electron number (N)
in the dot, and approaching the unitary limit (where the transmission reaches
its maximum possible value). Moreover, we detect a previously unobserved Kondo
effect, occurring for even values of N in a magnetic field.Comment: 7 pages, pdf onl
Angles in Fuzzy Disc and Angular Noncommutative Solitons
The fuzzy disc, introduced by the authors of Ref.[1], is a disc-shaped region
in a noncommutative plane, and is a fuzzy approximation of a commutative disc.
In this paper we show that one can introduce a concept of angles to the fuzzy
disc, by using the phase operator and phase states known in quantum optics. We
gave a description of a fuzzy disc in terms of operators and their commutation
relations, and studied properties of angular projection operators. A similar
construction for a fuzzy annulus is also given. As an application, we
constructed fan-shaped soliton solutions of a scalar field theory on a fuzzy
disc, which corresponds to a fan-shaped D-brane. We also applied this concept
to the theory of noncommutative gravity that we proposed in Ref.[2]. In
addition, possible connections to black hole microstates, holography and an
experimental test of noncommutativity by laser physics are suggested.Comment: 24 pages, 12 figures; v2: minor mistake corrected in Eq.(3.21), and
discussion adapted accordingly; v3: a further discussion on the algebra of
the fuzzy disc added in subsection 3.2; v4: discussions improved and typos
correcte
Insensitivity of Human iPS Cells-derived Mesenchymal Stem Cells to Interferon-Îł -induced HLA Expression Potentiates Repair Efficiency of Hind Limb Ischemia in Immune Humanized NOD Scid Gamma Mice
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