100,745 research outputs found
Timor-Leste human development report 2011 : managing natural resources for human development : developing the non-oil economy to achieve the MDGs
No full textPrincipal Author John G Taylor, Coordinator Rui Gomes, Authors, Technical Background Papers Tobias N. Rasmussen, Andrew Rosser, Martin Sandbu, Michael Ross, Tibor van Staveren, Ricardo F. Neupert, Rui A. Gomes, John G Taylor, Sonny Harmadi, Hafiz Pash
Investigation of the Neupert effect in solar flares
No full textBased on a sample of 1114 flares observed simultaneously in
hard X-rays (HXR) by the BATSE instrument and in soft X-rays (SXR) by
GOES, we studied several aspects of the Neupert effect and its interpretation in the
frame of the electron-beam-driven evaporation model. In particular,
we investigated the time differences () between the maximum of the
SXR emission and the end of the HXR emission, which are expected to occur at
almost the same time. Furthermore, we performed a detailed analysis of the SXR peak
flux – HXR fluence relationship for the complete set of events, as well as separately
for subsets of events which are likely compatible/incompatible with the timing
expectations of the Neupert effect. The distribution of the time
differences reveals a pronounced peak at . About half of the events
show a timing behavior which can be considered to be consistent with the
expectations from the Neupert effect. For these events, a high correlation between
the SXR peak flux and the HXR fluence is obtained, indicative of
electron-beam-driven evaporation. However, there is also a significant
fraction of flares (about one fourth), which show strong deviations from
, with a prolonged increase of the SXR emission distinctly
beyond the end of the HXR emission. These results suggest that electron-beam-driven
evaporation plays an important role in solar flares. Yet, in a significant fraction
of events, there is also clear evidence for the presence of an additional
energy transport mechanism other than nonthermal electron beams,
where the relative contribution is found to vary with the flare importance
Characterization of Translocation Contact Sites Involved in the Import of Mitochondrial Proteins
No full textImport of proteins into the mitochondrial matrix requires translocation across two membranes. Translocational intermediates of mitochondrial proteins, which span the outer and inner membrane simultaneously and thus suggest that translocation occurs in one step, have recently been described (Schleyer, M., and W. Neupert, 1985, Cell, 43:339-350). In this study we present evidence that distinct membrane areas are involved in the translocation process. Mitochondria that had lost most of their outer membrane by digitonin treatment (mitoplasts) still had the ability to import proteins. Import depended on proteinaceous structures of the residual outer membrane and on a factor that is located between the outer and inner membranes and that could be extracted with detergent plus salt. Translocational intermediates, which had been preformed before fractionation, remained with the mitoplasts under conditions where most of the outer membrane was subsequently removed. Submitochondrial vesicles were isolated in which translocational intermediates were enriched. Immunocytochemical studies also suggested that the translocational intermediates are located in areas where outer and inner membranes are in close proximity. We conclude that the membrane-potential-dependent import of precursor proteins involves translocation contact sites where the two membranes are closely apposed and are linked in a stable manner
Mitochondrial porin of Neurospora crassa
No full textcDNA encoding porin of Neurospora crassa, the major protein component of the outer mitochondrial membrane, was isolated and the nucleotide sequence was determined. The deduced protein sequence consists of 283 amino acids (29,979 daltons) and shows sequence homology of around 43% to yeast porin; however, no significant homology to bacterial porins was apparent. According to secondary structure predictions, mitochondrial porin consists mainly of membrane-spanning sided beta-sheets. Porin was efficiently synthesized in vitro from the cDNA; this allowed us to study in detail its import into mitochondria. Thereby, three characteristics of import were defined: (i) import depended on the presence of nucleoside triphosphates; (ii) involvement of a proteinaceous receptor-like component on the surface of the mitochondria was demonstrated; (iii) insertion into the outer membrane was resolved into at least two distinct steps: specific binding to high-affinity sites and subsequent assembly to the mature form
Topological Crystalline Insulators
No full textWe give an introduction to topological crystalline insulators, that is, gapped ground states of quantum matter that are not adiabatically connected to an atomic limit without breaking symmetries that include spatial transformations, like mirror or rotational symmetries. To deduce the topological properties, we use non-Abelian Wilson loops. We also discuss in detail higher-order topological insulators with hinge and corner states, and in particular, present interacting bosonic models for the latter class of systems
Protein translocation across mitochondrial membranes
No full textProtein translocation across biological membranes is of fundamental importance for the biogenesis of organelles and in protein secretion. We will give an overview of the recent achievements in the understanding of protein translocation across mitochondrial membranes(1-5). In particular we will focus on recently identified components of the mitochondrial import apparatus
Deleted (wrong upload)
No full textCheck new version available.When using this dataset, please cite the original publication as follows:
Dennler, N., Foncubierta-Rodriguez, A., Neupert, T., & Sousa, M. (2021). Learning-based defect recognition for quasi-periodic HRSTEM images. Micron, 146(July 2020), 103069. https://doi.org/10.1016/j.micron.2021.10306
- …
