School Finance Systems and Their Responsiveness to Performance Pressures: A Case Study of Texas

Details the mechanisms of and influences on the state's school finance system, changes caused by increased performance pressures, local officials' ability to allocate resources as deemed appropriate, and obstacles to linking resources to student learning

School Finance Systems and Their Responsiveness to Performance Pressures: A Case Study of North Carolina

Details the mechanisms of and influences on the state's school finance system, changes caused by increased performance pressures, local officials' views on alternative allocation of resources, and obstacles to linking resources to student learning

Administration of the GABAA receptor antagonist picrotoxin into rat supramammillary nucleus induces c-Fos in reward-related brain structures. Supramammillary picrotoxin and c-Fos expression

<p>Abstract</p> <p>Background</p> <p>Picrotoxin blocks GABA_Areceptors, whose activation typically inhibits neuronal firing activity. We recently found that rats learn to selectively self-administer picrotoxin or bicuculline, another GABA_Areceptor antagonist, into the supramammillary nucleus (SuM), a posterior hypothalamic structure localized anterior to the ventral tegmental area. Other drugs such as nicotine or the excitatory amino acid AMPA are also self-administered into the SuM. The SuM appears to be functionally linked with the mesolimbic dopamine system and is closely connected with other brain structures that are implicated in motivational processes, including the prefrontal cortex, septal area, preoptic area, lateral hypothalamic area and dorsal raphe nucleus. Here, we hypothesized that these brain structures are activated by picrotoxin injections into the SuM.</p> <p>Results</p> <p>Picrotoxin administration into the SuM markedly facilitated locomotion and rearing. Further, it increased c-Fos expression in this region, suggesting blockade of tonic inhibition and thus the disinhibition of local neurons. This manipulation also increased c-Fos expression in structures including the ventral tegmental area, medial shell of the nucleus accumbens, medial prefrontal cortex, septal area, preoptic area, lateral hypothalamic area and dorsal raphe nucleus.</p> <p>Conclusions</p> <p>Picrotoxin administration into the SuM appears to disinhibit local neurons and recruits activation of brain structures associated with motivational processes, including the mesolimbic dopamine system, prefrontal cortex, septal area, preoptic area, lateral hypothalamic area and dorsal raphe nucleus. These regions may be involved in mediating positive motivational effects triggered by intra-SuM picrotoxin.</p

Using a runway paradigm to assess the relative strength of rats' motivations for enrichment objects

Laboratory animals should be provided with enrichment objects in their cages; however, it is first necessary to test whether the proposed enrichment objects provide benefits that increase the animals’ welfare. The two main paradigms currently used to assess proposed enrichment objects are the choice test, which is limited to determining relative frequency of choice, and consumer demand studies, which can indicate the strength of a preference but are complex to design. Here, we propose a third methodology: a runway paradigm, which can be used to assess the strength of an animal’s motivation for enrichment objects, is simpler to use than consumer demand studies, and is faster to complete than typical choice tests. Time spent with objects in a standard choice test was used to rank several enrichment objects in order to compare with the ranking found in our runway paradigm. The rats ran significantly more times, ran faster, and interacted longer with objects with which they had previously spent the most time. It was concluded that this simple methodology is suitable for measuring rats’ motivation to reach enrichment objects. This can be used to assess the preference for different types of enrichment objects or to measure reward system processes

Contrasting pressure evolution of f-electron hybridized states in CeRhIn5 and YbNi3 Ga9 : An optical conductivity study

Optical conductivity [σ (ω)] of CeRhIn5 and YbNi3Ga9 have been measured at external pressures to 10 GPa and at low temperatures to 6 K. Regarding CeRhIn5, at ambient pressure the main feature in σ (ω) is a Drude peak due to free carriers. With increasing pressure, however, a characteristic midinfrared (mIR) peak rapidly develops in σ (ω), and its peak energy and width increase with pressure. These features are consistent with an increased conduction (c)- f electron hybridization at high pressure and show that pressure has tuned the electronic state of CeRhIn5 from very weakly to strongly hybridized ones. As for YbNi3Ga9, in contrast, a marked mIR peak is observed already at ambient pressure, indicating a strong c- f hybridization. At high pressures, however, the mIR peak shifts to lower energy and becomes diminished and seems to merge with the Drude component at 10 GPa. Namely, CeRhIn5 and YbNi3Ga9 exhibit some opposite tendencies in the pressure evolution of σ (ω) and electronic structure. These results are discussed in terms of the pressure evolution of c- f hybridized electronic states in Ce and Yb compounds, in particular in terms of the electron-hole symmetry often considered between Ce and Yb