ODP Leg 137, borehole fluid chemistry in Hole 504B

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95686/1/grl5867.pd

Characterising the baseband impedance of supply modulators using simple modulated signals

Envelope tracking is one of the promising technologies for 5G power amplifiers, providing high power efficiency over a wide output power range by modulating the supply voltage. Although the baseband impedance, the output impedance of the supply modulator, plays a crucial role in the linearity of the PA, it is often not measured or considered during the modulator design. This paper presents a new, simplified approach to characterising this impedance using a PA with a simple multi-tone modulation as a load. It describes the measurement setup and verifies the results by characterising the baseband impedance of a state-of-the-art buck converter and comparing this to its static model. The results demonstrate that multi-tone signals and complex modulations yield comparable results and are both suitable for measuring and modelling the baseband impedance. This shows that using simple multi-tone measurements and basic equipment, the full static impedance characteristic can be obtained

Design Considerations for Secure and Usable Authentication on Situated Displays

Users often need to authenticate at situated displays in or- der to, for example, make purchases, access sensitive in- formation, or confirm an identity. However, the exposure of interactions in public spaces introduces a large attack surface (e.g., observation, smudge or thermal attacks). A plethora of authentication models and input modalities that aim at disguising users’ input has been presented in the past. However, a comprehensive analysis on the re- quirements for secure and usable authentication on public displays is still missing. This work presents 13 design con- siderations suitable to inform practitioners and researchers during the development process of authentication systems for situated displays in public spaces. It draws on a com- prehensive analysis of prior literature and subsequent dis- cussion with five experts in the fields of pervasive displays, human-computer-interaction and usable security

Microbial colonization influences early B-lineage development in the gut lamina propria

The RAG1/RAG2 endonuclease ("RAG") initiates the V(D)J recombination reaction that assembles Ig heavy (IgH) and light (IgL) chain variable region exons from germline gene segments to generate primary antibody repertoires1. IgH V(D)J assembly occurs in progenitor (pro-) B cells followed by that of IgL in precursor (pre-) B cells. Expression of IgH μ and IgL (Igκ or Igλ) chains generates IgM, which is expressed on immature B cells as the B cell antigen-binding receptor ("BCR"). Rag expression can continue in immature B cells2, allowing continued Igκ V(D)J recombination that replaces the initial VκJκ exon with one that generates a new specificity3–5. This “receptor editing” process, which also can lead to Igλ V(D)J recombination and expression3,6,7, provides a mechanism whereby antigen-encounter at the Rag-expressing immature B cell stage helps shape pre-immune BCR repertoires. As the major site of post-natal B cell development, the bone marrow is the principal location of primary Ig repertoire diversification in mice. Here, we report that early B cell development also occurs within the mouse intestinal lamina propria (LP), where the associated V(D)J recombination/receptor editing processes modulate primary LP Ig repertoires. At weanling age in normally housed mice, the LP contains a population of Rag-expressing B lineage cells that harbor intermediates indicative of ongoing V(D)J recombination and which contain cells with pro-B, pre-B, and editing phenotypes. Consistent with LP-specific receptor editing, Rag-expressing LP B-lineage cells have similar VH repertoires, but significantly different Vκ repertoires, compared to those of Rag2-expressing BM counterparts. Moreover, colonization of germ-free mice leads to an increased ratio of Igλ-expressing versus Igκ-expressing B cells specifically in the LP. We conclude that B cell development occurs in the intestinal mucosa, where it is regulated by extra-cellular signals from commensal microbes that influence gut Ig repertoires

Political Polarization as a Constraint on Corruption: A Cross-National Comparison

Efforts to explain corruption have increased dramatically in recent years. The interest stems from the increasing weight economists assign to corruption when explaining economic growth. Much research focuses on how political institutions influence perceptions of corruption. We move this debate in a new direction by addressing a previously ignored dimension: ideological polarization. We contend perceptions of corruption are determined not only by specific institutional features of the political system–such as elements of voting systems, ballot structures, or separation of powers–but by who sits at the controls. We employ panel data from a broad variety of countries to test our theoretical argument. Contrary to recent findings by both economists and political scientists, we show that ideological polarization predicts perceptions of corruption

Immature B cells preferentially switch to IgE with increased direct Sμ to Sε recombination

Immunoglobulin heavy chain (IgH) class-switch recombination (CSR) replaces initially expressed Cμ (IgM) constant regions (C(H)) exons with downstream C(H) exons. Stimulation of B cells with anti-CD40 plus interleukin-4 induces CSR from Cμ to Cγ1 (IgG1) and Cε (IgE), the latter of which contributes to the pathogenesis of atopic diseases. Although Cε CSR can occur directly from Cμ, most mature peripheral B cells undergo CSR to Cε indirectly, namely from Cμ to Cγ1, and subsequently to Cε. Physiological mechanisms that influence CSR to Cγ1 versus Cε are incompletely understood. In this study, we report a role for B cell developmental maturity in IgE CSR. Based in part on a novel flow cytometric IgE CSR assay, we show that immature B cells preferentially switch to IgE versus IgG1 through a mechanism involving increased direct CSR from Cμ to Cε. Our findings suggest that IgE dysregulation in certain immunodeficiencies may be related to impaired B cell maturation

Studying Cat (Felis catus) Diabetes: Beware of the Acromegalic Imposter

Naturally occurring diabetes mellitus (DM) is common in domestic cats (Felis catus). It has been proposed as a model for human Type 2 DM given many shared features. Small case studies demonstrate feline DM also occurs as a result of insulin resistance due to a somatotrophinoma. The current study estimates the prevalence of hypersomatotropism or acromegaly in the largest cohort of diabetic cats to date, evaluates clinical presentation and ease of recognition. Diabetic cats were screened for hypersomatotropism using serum total insulin-like growth factor-1 (IGF-1; radioimmunoassay), followed by further evaluation of a subset of cases with suggestive IGF-1 (>1000 ng/ml) through pituitary imaging and/ or histopathology. Clinicians indicated pre-test suspicion for hypersomatotropism. In total 1221 diabetic cats were screened; 319 (26.1%) demonstrated a serum IGF-1>1000 ng/ml (95% confidence interval: 23.6-28.6%). Of these cats a subset of 63 (20%) underwent pituitary imaging and 56/63 (89%) had a pituitary tumour on computed tomography; an additional three on magnetic resonance imaging and one on necropsy. These data suggest a positive predictive value of serum IGF-1 for hypersomatotropism of 95% (95% confidence interval: 90-100%), thus suggesting the overall hypersomatotropism prevalence among UK diabetic cats to be 24.8% (95% confidence interval: 21.2-28.6%). Only 24% of clinicians indicated a strong pre-test suspicion; most hypersomatotropism cats did not display typical phenotypical acromegaly signs. The current data suggest hypersomatotropism screening should be considered when studying diabetic cats and opportunities exist for comparative acromegaly research, especially in light of the many detected communalities with the human disease

A pseudomolecule assembly of the Rocky Mountain elk genome

Rocky Mountain elk (Cervus canadensis) populations have significant economic implications to the cattle industry, as they are a major reservoir for Brucella abortus in the Greater Yellowstone area. Vaccination attempts against intracellular bacterial diseases in elk populations have not been successful due to a negligible adaptive cellular immune response. A lack of genomic resources has impeded attempts to better understand why vaccination does not induce protective immunity. To overcome this limitation, PacBio, Illumina, and Hi-C sequencing with a total of 686-fold coverage was used to assemble the elk genome into 35 pseudomolecules. A robust gene annotation was generated resulting in 18,013 gene models and 33,422 mRNAs. The accuracy of the assembly was assessed using synteny to the red deer and cattle genomes identifying several chromosomal rearrangements, fusions and fissions. Because this genome assembly and annotation provide a foundation for genome-enabled exploration of Cervus species, we demonstrate its utility by exploring the conservation of immune system-related genes. We conclude by comparing cattle immune system-related genes to the elk genome, revealing eight putative gene losses in elk