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BackgroundEstrogen increases dramatically during pregnancy, but quickly drops below pre-pregnancy levels at birth and remains suppressed during the postpartum period. Clinical and rodent work suggests that this postpartum drop in estrogen results in an “estrogen withdrawal” state that is related to changes in affect, mood, and behavior. Most studies examining the effect of estrogen withdrawal on the brain have focused solely on the hippocampus.MethodsWe used a hormone-simulated pseudopregnancy model in Syrian hamsters, a first for this species. Ovariectomized females were given daily injections to approximate hormone levels during gestation and then withdrawn from estrogen to simulate postpartum estrogen withdrawal. Subjects were tested for behavioral assays of anxiety and anhedonia during estrogen withdrawal. Following sacrifice, neuroplasticity in oxytocin-producing neurons in the paraventricular nucleus of the hypothalamus (PVH) and its efferent targets was measured.ResultsEstrogen-withdrawn females had increased anxiety-like behaviors in the elevated plus and open field, but did not differ from controls in sucrose preference. Furthermore, estrogen-withdrawn females had more oxytocin-immunoreactive cells and oxytocin mRNA in the PVH, as well as an increase in oxytocin receptor density in the dorsal raphe nucleus (DRN). Finally, blocking oxytocin receptors in the DRN during estrogen withdrawal prevented the high-anxiety behavioral phenotype in estrogen-withdrawn females.ConclusionsEstrogen withdrawal alters oxytocin signaling in the PVH and DRN to increase anxiety-like behavior during the postpartum period. More broadly, these experiments suggest Syrian hamsters as a novel organism in which to model the effects of postpartum estrogen withdrawal on the brain and anxiety-like behavior.

Background Estrogen increases dramatically during pregnancy but quickly drops below prepregnancy levels at birth and remains suppressed during the postpartum period. Clinical and rodent work suggests that this postpartum drop in estrogen results in an estrogen withdrawal state that is related to changes in affect, mood, and behavior. How estrogen withdrawal affects oxytocin (OT) neurocircuitry has not been examined. Methods We used a hormone-simulated pseudopregnancy followed by estrogen withdrawal in Syrian hamsters, a first for this species. Ovariectomized females were given daily injections to approximate hormone levels during gestation and then withdrawn from estrogen to simulate postpartum estrogen withdrawal. These hamsters were tested for behavioral assays of anxiety and anhedonia during estrogen withdrawal. Neuroplasticity in OT-producing neurons in the paraventricular nucleus of the hypothalamus and its efferent targets was measured. Results Estrogen-withdrawn females had increased anxiety-like behaviors in the elevated plus maze and open field tests but did not differ from control females in sucrose preference. Furthermore, estrogen-withdrawn females had more OT-immunoreactive cells and OT messenger RNA in the paraventricular nucleus of the hypothalamus and an increase in OT receptor density in the dorsal raphe nucleus. Finally, blocking OT receptors in the dorsal raphe nucleus during estrogen withdrawal prevented the high-anxiety behavioral phenotype in estrogen-withdrawn females. Conclusions Estrogen withdrawal induces OT neuroplasticity in the paraventricular nucleus of the hypothalamus and dorsal raphe nucleus to increase anxiety-like behavior during the postpartum period. More broadly, these experiments suggest Syrian hamsters as a novel organism in which to model the effects of postpartum estrogen withdrawal on the brain and anxiety-like behavior.

Long-term beam-electron cloud interaction is modeled with a 3D parallel continuous model originally developed for plasma wakefield acceleration modeling. The simulation results are compared with the two macro-particle model for strong head-tail instability. The two macro- particle model qualitatively captures some of the instability features of the beam. The code is then used to model and make predictions for the beam dynamics in the presence of an electron cloud for several present and future circular machines around the world.

The study contains a theoretical and experimental evaluation of the mechanical behavior of wires in a flexible (“Euler”) test probe, including buckling, axial and lateral deflections and stresses. The developed formulas are simple, easy-to-use and clearly indicate the role of the major factors affecting the wire performance. Calculations, executed for an Everett-Charles 32 point probe, are in good agreement with the measured data. Some recommendations for smaller stresses in the wires are presented. The obtained results could be of help in the analysis and physical design of “Euler” test probes.

For the Beta Beams to become a solid option for a future neutrino-physics facility at CERN, it is fundamental to demonstrate the feasibility of storing and accelerating the Beta Beams ions in the PS and SPS. This work identifies the key issues that should be assessed for the PS, presents the status of the ongoing studies and, in particular, discusses the choice of the injection energy and recent space-charge measurements.

After the rout of Caporetto, Italians became familiar with American uniforms mainly due to the presence of American Red Cross (ARC) workers. Throughout Italy, they represented mythic America, its munificence, effectiveness and concern for the common man. Italy’s campaign was second only to France’s for budget and range. Relief to soldiers was a small part of ARC’s activity, since most of it went to civilians. Its main target was to support all components of society, nursing their ‘wounds of the spirit’—demoralisation, unrest, and the tendency to revolutionary violence. Therefore, its actions combined assistance with propaganda for war, Wilson’s aims, and American models, playing essentially political roles. This chapter analyses ARC’s publicity system, its strategies and relations with the population at large.