Fast Calculation Methods in Collective Dynamical Models of Beam/Plasma Physics

We consider an application of modification of our variational-wavelet approach to some nonlinear collective model of beam/plasma physics: Vlasov/Boltzmann-like reduction from general BBGKY hierachy related to modeling of propagation of intense charged particle beams in high-intensity accelerators and transport systems. We use fast convergent multiscale variational-wavelet representations for solutions which allow to consider polynomial and rational type of nonlinearities. The solutions are represented via the multiscale decomposition in nonlinear high-localized eigenmodes (waveletons). In contrast with different approaches we do not use perturbation technique or linearization procedures.Comment: 4 pages, 2 figures, JAC2001.cls, presented at European Particle Accelerator Conference (EPAC02), Paris, June 3-7, 2002; changed from A4 to US format for correct printin

The political ambitions and influences of the Balliol dynasty, c.1210-1364

This study examines the importance of the Balliol dynasty in the thirteenth and fourteenth centuries through their political ambitions and influences in the three realms of Scotland, England and France. The generally accepted opinion in previous historiography that John (II), king of Scots from 1292-96 (d. 1314) and Edward Balliol (d. 1364) were politically weak men and unsuccessful kings has not been challenged until recently, when historians began evaluating the family from a British approach. Despite this, challenges have remained and it has been necessary to re-examine the life of John (I) (d. 1268) in order to bring a new perspective to the Balliol family. During the eleventh and twelfth centuries, the Balliols had slowly increased their power and influence in English politics, acquiring a significant landed wealth, which, by the early thirteenth century, propelled the family into a class of leading nobles. At this point in 1229, John (I) inherited his father's wealth and position and would substantially increase the family's influence in England and Scotland over the next four decades, while retaining their French links. The influence that John (I) had in the three realms and his relationships with kings Alexander II and Alexander III of Scotland and Henry III of England have been thoroughly examined in this study and have uncovered John (I)'s power and ambition as an independent lord, who remained wholly English in identity. With this evidence, a new perspective has developed. In reassessing John (I), the Balliols are revealed as committed English lords and loyal servants of the kings of England. This has thrown new light on the political roles of John (II) and Edward Balliol and underlines how the family has been unfairly judged through centuries by both chroniclers and historians who have assessed them as Scottish kings rather than as English lords. With this new perspective, the political roles of King John (1292-96) and King Edward (1332-5 6), before, during and after their respective kingships have been reexamined and re-evaluated. Admittedly, both men lacked the power which John (I) possessed in his lifetime under Henry III, and although John (I) had laid the foundations for a great baronial dynasty, the deaths of Hugh Balliol (d. 1271) and Alexander Balliol (d. 1278) limited the territorial base which John (II) would inherit. Similarly, King John's deposition in 1296 would alter any strong landed and political following to which Edward Balliol might have hoped to succeed. Despite the loss of wealth in the 1270s and the forfeiture of the Balliol estates in England and Scotland in 1296, John (II) and Edward still retained close relationships with the successive English kings and used these connections to fuel their political ambitions. Their kingships illustrate their desires to recover some influence in English politics which the family had enjoyed in the mid-thirteenth century. However, the decrease in landed wealth resulted in a less significant baronial identity within the Scottish and English political communities and perhaps affected their roles as Scottish kings. The reassessment of the Balliols as Anglo-Scottish lords has underlined their relationship with the English crown and the political nature of the family

Space platform

The space platform subsystem design characteristics are described in detail. Compatibility with the STS/orbiter is an important factor

Neuronal junctophilins recruit specific Cav and RyR isoforms to ER-PM junctions and functionally alter Cav2.1 and Cav2.2

Junctions between the endoplasmic reticulum and plasma membrane that are induced by the neuronal junctophilins are of demonstrated importance, but their molecular architecture is still poorly understood and challenging to address in neurons. This is due to the small size of the junctions and the multiple isoforms of candidate junctional proteins in different brain areas. Using colocalization of tagged proteins expressed in tsA201 cells, and electrophysiology, we compared the interactions of JPH3 and JPH4 with different calcium channels. We found that JPH3 and JPH4 caused junctional accumulation of all the tested high-voltage-activated CaV isoforms, but not a low-voltage-activated CaV. Also, JPH3 and JPH4 noticeably modify CaV2.1 and CaV2.2 inactivation rate. RyR3 moderately colocalized at junctions with JPH4, whereas RyR1 and RyR2 did not. By contrast, RyR1 and RyR3 strongly colocalized with JPH3, and RyR2 moderately. Likely contributing to this difference, JPH3 binds to cytoplasmic domain constructs of RyR1 and RyR3, but not of RyR2

Junctophilins 1, 2, and 3 all support voltage-induced Ca2+ release despite considerable divergence

In skeletal muscle, depolarization of the plasma membrane (PM) causes conformational changes of the calcium channel CaV1.1 that then activate RYR1 to release calcium from the SR. Being independent of extracellular calcium entry, this process is termed voltage-induced calcium release. In skeletal muscle, junctophilins (JPHs) 1 and 2 form the SR–PM junctions at which voltageinduced calcium release occurs. Previous work demonstrated that JPH2 is able to recapitulate voltage-induced calcium release when expressed in HEK293 cells together with CaV1.1, β1a, Stac3, and RYR1. However, it is unknown whether JPH1 and the more distantly related neuronal JPH3 and JPH4 might also function in this manner, a question of interest because different JPH isoforms diverge in their interactions with RYR1. Here, we show that, like JPH2, JPH1 and JPH3, coexpressed with CaV1.1, β1a, Stac3, and RYR1 in HEK293 cells, cause colocalization of CaV1.1 and RYR1 at ER–PM junctions. Furthermore, potassium depolarization elicited cytoplasmic calcium transients in cells in which WT CaV1.1 was replaced with the calcium impermeant mutant CaV1.1(N617D), indicating that JPH1, JPH2, and JPH3 can all support voltage-induced calcium release, despite sequence divergence and differences in interaction with RYR1. Conversely, JPH4-induced ER–PM junctions contain CaV1.1 but not RYR1, and cells expressing JPH4 are unable to produce depolarization-induced calcium transients. Thus, JPHs seem to act primarily to form ER–PM junctions and to recruit the necessary signaling proteins to these junctions but appear not to be directly involved in the functional interactions between these proteins

Effects of lattice distortion and Jahn–Teller coupling on the magnetoresistance of La0.7Ca0.3MnO3 and La0.5Ca0.5CoO3 epitaxial films

Studies of La0.7Ca0.3MnO3 epitaxial films on substrates with a range of lattice constants reveal two dominant contributions to the occurrence of colossal negative magnetoresistance (CMR) in these manganites: at high temperatures (T → TC, TC being the Curie temperature), the magnetotransport properties are predominantly determined by the conduction of lattice polarons, while at low temperatures (T ≪ TC/, the residual negative magnetoresistance is correlated with the substrate-induced lattice distortion which incurs excess magnetic domain wall scattering. The importance of lattice polaron conduction associated with the presence of Jahn–Teller coupling in the manganites is further verified by comparing the manganites with epitaxial films of another ferromagnetic perovskite, La0.5Ca0.5CoO3. Regardless of the differences in the substrate-induced lattice distortion, the cobaltite films exhibit much smaller negative magnetoresistance, which may be attributed to the absence of Jahn–Teller coupling and the high electron mobility that prevents the formation of lattice polarons. We therefore suggest that lattice polaron conduction associated with the Jahn–Teller coupling is essential for the occurrence of CMR, and that lattice distortion further enhances the CMR effects in the manganites

De novo reconstitution reveals the proteins required for skeletal muscle voltage-induced Ca2+ release

Skeletal muscle contraction is triggered by Ca2+ release from the sarcoplasmic reticulum (SR) in response to plasma membrane (PM) excitation. In vertebrates, this depends on activation of the RyR1 Ca2+ pore in the SR, under control of conformational changes of CaV1.1, located ∼12 nm away in the PM. Over the last ∼30 y, gene knockouts have revealed that CaV1.1/RyR1 coupling requires additional proteins, but leave open the possibility that currently untested proteins are also necessary. Here, we demonstrate the reconstitution of conformational coupling in tsA201 cells by expression of CaV1.1, β1a, Stac3, RyR1, and junctophilin2. As in muscle, depolarization evokes Ca2+ transients independent of external Ca2+ entry and having amplitude with a saturating dependence on voltage. Moreover, freeze-fracture electron microscopy indicates that the five identified proteins are sufficient to establish physical links between CaV1.1 and RyR1. Thus, these proteins constitute the key elements essential for excitation-contraction coupling in skeletal muscle

Accessibility of Targeted DHPR Sites to Streptavidin and Functional Effects of Binding on EC Coupling

In skeletal muscle, the dihydropyridine receptor (DHPR) in the plasma membrane (PM) serves as a Ca2+ channel and as the voltage sensor for excitation–contraction (EC coupling), triggering Ca2+ release via the type 1 ryanodine receptor (RyR1) in the sarcoplasmic reticulum (SR) membrane. In addition to being functionally linked, these two proteins are also structurally linked to one another, but the identity of these links remains unknown. As an approach to address this issue, we have expressed DHPR α1S or β1a subunits, with a biotin acceptor domain fused to targeted sites, in myotubes null for the corresponding, endogenous DHPR subunit. After saponin permeabilization, the ∼60-kD streptavidin molecule had access to the β1a N and C termini and to the α1S N terminus and proximal II–III loop (residues 671–686). Steptavidin also had access to these sites after injection into living myotubes. However, sites of the α1S C terminus were either inaccessible or conditionally accessible in saponin- permeabilized myotubes, suggesting that these C-terminal regions may exist in conformations that are occluded by other proteins in PM/SR junction (e.g., RyR1). The binding of injected streptavidin to the β1a N or C terminus, or to the α1S N terminus, had no effect on electrically evoked contractions. By contrast, binding of streptavidin to the proximal α1S II–III loop abolished such contractions, without affecting agonist-induced Ca2+ release via RyR1. Moreover, the block of EC coupling did not appear to result from global distortion of the DHPR and supports the hypothesis that conformational changes of the α1S II–III loop are necessary for EC coupling in skeletal muscle

Perspectives of Pre-Service Teachers on Students with Emotional Disabilities

Perceptions of working with students of emotional disabilities or who are considered Emotionally/Behaviorally Disturbed (E/BD) is varied across the spectrum. However, one constant that does hold true is that all pre-service teachers have some hesitation in working with such students, especially if they lack any previous exposure to students with E/BD. This study compared pre- and post-test Likert-scale type surveys about pre-service teachers’ (n = 35) perceptions regarding students with E/BD. In between the pre- and post-test, the pre-service teachers were given classroom instruction and were assigned a practicum field experience to observe and work alongside students with emotionally charged behaviors housed in an alternative educational facility. The scores were analyzed via a paired t-test and findings revealed that practical observation experience at an alternative school setting for E/BD students and instruction on behavior management strategies had a significantly positive effect on survey respondents’ perceptions regarding E/BD students