Thomson\u27s E/m Experiment Revisited

The objective of this experiment is to familiarize the student with the impulse theorem, electron dynamics, and magnetic field contours. He is challenged to obtain accurate as well as precise measurements with suboptimum apparatus through correct analysis. He also investigates the influence of various systematic errors using model calculations on a small computer. © 1972, American Association of Physics Teachers. All rights reserved

Lost at sea: Identifying the post-depositional alteration of amphorae in ancient shipwrecks

The present paper sheds new light on the alteration of archaeological ceramics buried in marine environments by analysing in detail a large dataset of Hellenistic and Late Roman Republican transport amphorae from 15 sites along the well-known ancient maritime trade route off the Dalmatian coast in southern Croatia. These include amphorae from shipwrecks, kiln sites and settlements. Ceramic petrography and instrumental neutron activation analysis (INAA) have been used to compare sherds of amphorae made in the same workshop, of the same fabric and origin, but recovered from both shipwrecks and terrestrial sites and were therefore exposed to different burial environments over two millennia. The integration of both methods permitted the identification of differential microstructural and geochemical alteration of the amphorae under the sea relative to those found on land. By applying principal components analysis and test statistics, we have detected enrichment of As, Ca, Na, Sb, Sr and U and depletion of Ba, Cs, K and Rb in amphorae from the marine environment, relative to those buried on land. The implications of the study are discussed in terms of the provenance determination of amphorae from submerged environments and the reconstruction of ancient maritime trade routes

Social Interaction and Communities of Practice in Formative Period NW Argentina: A Multi-analytical Study of Ceramics

This is the author accepted manuscript. The final version is available from University of New Mexico Press via the link in this recordThe study of long-distance exchange of goods and resources has long been central to the understanding of socio-political and cultural complexity in the south-central Andes. Traditional studies have emphasized typological similarities to reconstruct regional networks, proposing the dominance of different centres through time. While these approaches were informative on the general direction of contacts, the nature and scale of interaction has remained speculative. This chapter summarises the latest results of our ongoing research project on long-distance circulation of archaeological materials in northwestern Argentina during part of the Formative Period (ca. 1500 BC-AD 1000). The study applied a multianalytical methodological strategy integrating archaeological analysis with archaeometric techniques, including thin section petrography, instrumental neutron activation analysis (INAA) and laser ablation inductively coupled massspectometry (LA-ICP-MS) in order to contribute an evidence-based holistic view of preHispanic exchange networks. The study examined materials traditionally studied separately, including 542 ceramic samples and 113 obsidian and volcanic rock artifacts, from seven sectors in the semi-arid valleys area. We summarize here the results of the ceramic analysis, showing the 19-2 following trends: (1) inter-valley heterogeneity of clay and fabrics for ordinary wares; (2) intervalley homogeneity of clay and fabrics for a wide range of decorated wares; (3) selective circulation of two distinct polychrome wares. These trends reflect the complex inter-community relationships experienced in small-scale societies. The study offers a new platform to model ancient exchange, and circulation and interaction more broadly, based on actual material transfers. The results call for the re-examination of the centralized models of exchange and interaction that are often drawn upon to account for emergent cultural complexity in the past, both in the Andes and beyond.British AcademyArts and Humanities Research Council (AHRC)Argentinean National Agency for Science and Technology (ANPCyT)Raíces ProgramArgentinian National Council for Scientific and Technical Research (CONICET

Neutron activation analysis of pottery samples from Abila of the Decapolis

Instrumental neutron activation analyses have been performed on samples of pottery from Abila of the Decapolis (northern Jordan) ranging in age from Early Bronze to Islamic (Abassid). Preliminary results suggest several groupings of samples from each of twelve major archaeological periods, implying a common source of raw materials for ceramic manufacture at Abila for specimens within each grouping, and different sources of raw materials for specimens from different groupings.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43131/1/10967_2005_Article_898.pd

The Otterbein Miscellany - June 1984

https://digitalcommons.otterbein.edu/miscellany/1007/thumbnail.jp

UK Housing Market: Time Series Processes with Independent and Identically Distributed Residuals

The paper examines whether a univariate data generating process can be identified which explains the data by having residuals that are independent and identically distributed, as verified by the BDS test. The stationary first differenced natural log quarterly house price index is regressed, initially with a constant variance and then with a conditional variance. The only regression function that produces independent and identically distributed standardised residuals is a mean process based on a pure random walk format with Exponential GARCH in mean for the conditional variance. There is an indication of an asymmetric volatility feedback effect but higher frequency data is required to confirm this. There could be scope for forecasting the index but this is tempered by the reduction in the power of the BDS test if there is a non-linear conditional variance process

Species-level classification of the vaginal microbiome

Background The application of next-generation sequencing to the study of the vaginal microbiome is revealing the spectrum of microbial communities that inhabit the human vagina. High-resolution identification of bacterial taxa, minimally to the species level, is necessary to fully understand the association of the vaginal microbiome with bacterial vaginosis, sexually transmitted infections, pregnancy complications, menopause, and other physiological and infectious conditions. However, most current taxonomic assignment strategies based on metagenomic 16S rDNA sequence analysis provide at best a genus-level resolution. While surveys of 16S rRNA gene sequences are common in microbiome studies, few well-curated, body-site-specific reference databases of 16S rRNA gene sequences are available, and no such resource is available for vaginal microbiome studies. Results We constructed the Vaginal 16S rDNA Reference Database, a comprehensive and non-redundant database of 16S rDNA reference sequences for bacterial taxa likely to be associated with vaginal health, and we developed STIRRUPS, a new method that employs the USEARCH algorithm with a curated reference database for rapid species-level classification of 16S rDNA partial sequences. The method was applied to two datasets of V1-V3 16S rDNA reads: one generated from a mock community containing DNA from six bacterial strains associated with vaginal health, and a second generated from over 1,000 mid-vaginal samples collected as part of the Vaginal Human Microbiome Project at Virginia Commonwealth University. In both datasets, STIRRUPS, used in conjunction with the Vaginal 16S rDNA Reference Database, classified more than 95% of processed reads to a species-level taxon using a 97% global identity threshold for assignment. Conclusions This database and method provide accurate species-level classifications of metagenomic 16S rDNA sequence reads that will be useful for analysis and comparison of microbiome profiles from vaginal samples. STIRRUPS can be used to classify 16S rDNA sequence reads from other ecological niches if an appropriate reference database of 16S rDNA sequences is available

Self-oligomerization Regulates Stability of Survival Motor Neuron Protein Isoforms by Sequestering an SCF\u3csup\u3eSlmb\u3c/sup\u3e Degron

Spinal muscular atrophy (SMA) is caused by homozygous mutations in human SMN1. Expression of a duplicate gene (SMN2) primarily results in skipping of exon 7 and production of an unstable protein isoform, SMNΔ7. Although SMN2 exon skipping is the principal contributor to SMA severity, mechanisms governing stability of survival motor neuron (SMN) isoforms are poorly understood. We used a Drosophila model system and label-free proteomics to identify the SCFSlmb ubiquitin E3 ligase complex as a novel SMN binding partner. SCFSlmb interacts with a phosphor degron embedded within the human and fruitfly SMN YG-box oligomerization domains. Substitution of a conserved serine (S270A) interferes with SCFSlmb binding and stabilizes SMNΔ7. SMA-causing missense mutations that block multimerization of full-length SMN are also stabilized in the degron mutant background. Overexpression of SMNΔ7S270A, but not wild-type (WT) SMNΔ7, provides a protective effect in SMA model mice and human motor neuron cell culture systems. Our findings support a model wherein the degron is exposed when SMN is monomeric and sequestered when SMN forms higher-order multimers