EFFECT OF REVENUE INSURANCE ON ENTRY AND EXIT DECISIONS IN TABLE GRAPE PRODUCTION: A REAL OPTION APPROACH

This study determines the entry and exit thresholds of table grape farming with irreversible investment under uncertainty. Real option approach is adopted to consider the investment and management flexibility. Also revenue insurance is introduced to consider the effect of the risk management programs on the entry and exit thresholds. Results show that revenue insurance increases the entry and exit thresholds by 1% and 4%, respectively, thus discouraging new investment and current farming, as long as the revenue guarantee is less than the exit threshold. Revenue insurance increases the entry threshold by 3% and decreases the exit threshold by 13% as long as the revenue guarantee is greater than the exit threshold. In this case, revenue insurance discourages the investment and encourages the current farmer to stay in farming, further. However, the decrease in the subsidy rate results in the increase in both entry and exit thresholds. Thus, the premium subsidy levels should be carefully considered if the policy objective is to encourage growers to shift to higher-value crops.Risk and Uncertainty,

Comparison of durability indicators obtained by Non Destructive Testing methods to monitor the durability of concrete structures

International audienceThis paper deals with the use of non destructive testing methods (NDT) to assess indicators of concrete durability and mechanical properties of reinforced concrete structures. On site, NDT methods based on electromagnetic or ultrasonic wave propagation (such as radar, impact echo, ultrasonic transmission deviceÉ) are used because they are more or less sensitive to water content and mechanical properties depending on the method. It has been shown, in a former project [1, 2], that the NDT results called Òobservablesî are linked to mechanical and durability indicators (YoungÕs modulus, compressive strength, porosity and saturation degree). Meanwhile, the relationship between observables and indicators depends on the concrete mix design. A calibration protocol is then proposed to get this relationship for the right mix of the reinforced structure studied by using a minimal number of cores. The cores are non-destructively characterised in laboratory or used to determined reference indicators by standardised destructive methods. The aims of this paper are first to present the ND calibration protocol on cores and then to validate this proposed calibration protocol. To achieve this goal, some NDT results obtained on site and on the corresponding core are compared and durability indicators deduced from NDT calibration are compared with reference durability indicators

A role of melanin-concentrating hormone producing neurons in the central regulation of paradoxical sleep

BACKGROUND: Peptidergic neurons containing the melanin-concentrating hormone (MCH) and the hypocretins (or orexins) are intermingled in the zona incerta, perifornical nucleus and lateral hypothalamic area. Both types of neurons have been implicated in the integrated regulation of energy homeostasis and body weight. Hypocretin neurons have also been involved in sleep-wake regulation and narcolepsy. We therefore sought to determine whether hypocretin and MCH neurons express Fos in association with enhanced paradoxical sleep (PS or REM sleep) during the rebound following PS deprivation. Next, we compared the effect of MCH and NaCl intracerebroventricular (ICV) administrations on sleep stage quantities to further determine whether MCH neurons play an active role in PS regulation. RESULTS: Here we show that the MCH but not the hypocretin neurons are strongly active during PS, evidenced through combined hypocretin, MCH, and Fos immunostainings in three groups of rats (PS Control, PS Deprived and PS Recovery rats). Further, we show that ICV administration of MCH induces a dose-dependant increase in PS (up to 200%) and slow wave sleep (up to 70%) quantities. CONCLUSION: These results indicate that MCH is a powerful hypnogenic factor. MCH neurons might play a key role in the state of PS via their widespread projections in the central nervous system

Phosphorylation of microtubule-associated protein STOP by calmodulin kinase II.: Phosphorylation of STOP by CaMKII

International audienceSTOP proteins are microtubule-associated, calmodulin-regulated proteins responsible for the high degree of stabilization displayed by neuronal microtubules. STOP suppression in mice induces synaptic defects affecting both short and long term synaptic plasticity in hippocampal neurons. Interestingly, STOP has been identified as a component of synaptic structures in neurons, despite the absence of microtubules in nerve terminals, indicating the existence of mechanisms able to induce a translocation of STOP from microtubules to synaptic compartments. Here we have tested STOP phosphorylation as a candidate mechanism for STOP relocalization. We show that, both in vitro and in vivo, STOP is phosphorylated by the multifunctional enzyme calcium/calmodulin-dependent protein kinase II (CaMKII), which is a key enzyme for synaptic plasticity. This phosphorylation occurs on at least two independent sites. Phosphorylated forms of STOP do not bind microtubules in vitro and do not co-localize with microtubules in cultured differentiating neurons. Instead, phosphorylated STOP co-localizes with actin assemblies along neurites or at branching points. Correlatively, we find that STOP binds to actin in vitro. Finally, in differentiated neurons, phosphorylated STOP co-localizes with clusters of synaptic proteins, whereas unphosphorylated STOP does not. Thus, STOP phosphorylation by CaMKII may promote STOP translocation from microtubules to synaptic compartments where it may interact with actin, which could be important for STOP function in synaptic plasticity

Generation of 0.6 J pulses of 16 fs duration through high-repetition rate amplification of self phase modulated pulses

International audienceWe have generated optical pulses of 16fs duration in the submicrojoule range and at a repetition rate of 11 kHz. This was obtained by amplifying self-phase modulated pulses at the output of a fiber, using a couple of dyes to achieve gain covering a large spectrum around 620 n

Wirtschaftspolitik und wirtschaftliche Aussichten in den Industrieländern

Der vorliegende Bericht, der neunte in dieser Reihe, ist das Ergebnis einer Konferenz unabhängiger Ökonomen aus Japan, Westeuropa und Nordamerika. Wie auch im letzten Jahr, stand die Wirtschaftspolitik, die in den Ländern dieser drei Regionen betrieben wurde, im Mittelpunkt der Gespräche. Die Konferenz fand vom 2. -4. November 1977 bei der Brookings Institution in Washington unter dem Vorsitz des Unterzeichneten statt und wurde vom Institut für Weltwirtschaft, dem Japan Economic Research Center und der Brookings Institution gefördert. Die wirtschaftspolitischen Ergebnisse dieser Tagung wurden in einer Pressemitteilung zusammengefaßt und veröffentlicht. Dieser Bericht gibt Auskunft über den Hintergrund, auf dem die wirtschaftspolitischen Empfehlungen zustande kamen. Der erste Abschnitt beschreibt die wirtschaftliche Entwicklung während des vergangenen Jahres in jeder der drei Regionen. Dabei wird der Tatsache Rechnung getragen, daß die wirtschaftliche Entwicklung dieser Länder sowohl Gemeinsamkeiten als auch Unterschiede aufweist. Anschließend wird ein Ausblick für das kommende Jahr gegeben, und die wechselseitigen Einflüsse zwischen den Regionen werden kurz untersucht. Danach folgt eine Diskussion jener Probleme, die in allen oder zumindest den meisten Ländern bestehen und einer befriedigenderen wirtschaftlichen Entwicklung im Wege stehen. Der Bericht endet mit der Darstellung der wirtschaftspolitischen Empfehlungen der Gruppe. Die Tagung und dieser Bericht wurden durch die Förderung durch den German Marshall Fund ermöglicht, dessen Präsident, Robert Gerald Livingston, der Konferenz beiwohnte. Die Teilnehmer der Konferenz, die die wirtschaftspolitischen Empfehlungen erarbeiteten, taten dies im eigenen Namen, nicht aber für die Institute, denen sie angehören. Dieser Bericht wird in Europa vom Institut für Weltwirtschaft, in Japan vom Japan Economic Research Center und in Nordamerika von der Brookings Institution publiziert. --

Bullying and harassment and work-related stressors: Evidence from British small and medium enterprises

This article examines the relationship between work-related stressors and bullying and harassment in British small and medium sized enterprises (SMEs). Using representative data from a national survey on employment rights and experiences (Fair Treatment at Work) this research identifies that bullying and harassment is just as prevalent in British SMEs as in larger organizations. Drawing upon the Management Standards of the Health and Safety Executive a number of significant relationships with bullying and harassment are established. Work demands placed upon employees are positively related to bullying and harassment behaviours, whilst autonomy, manager support, peer support, and clarity of role are negatively associated with such behaviours. The study considers implications for human resource practices in SMEs and the risks of informal attitudes to these work-related stressors in contemporary workplaces are discussed