The Scope of Published Population Genetic Data for Indo-Pacific Marine Fauna and Future Research Opportunities in the Region

Marine biodiversity reaches its pinnacle in the tropical Indo-Pacific region, with high levels of both species richness and endemism, especially in coral reef habitats. While this pattern of biodiversity has been known to biogeographers for centuries, causal mechanisms remain enigmatic. Over the past 20 yrs, genetic markers have been employed by many researchers as a tool to elucidate patterns of biodiversity above and below the species level, as well as to make inferences about the underlying processes of diversification, demographic history, and dispersal. In a quantitative, comparative framework, these data can be synthesized to address questions about this bewildering diversity by treating species as “replicates.” However, the sheer size of the Indo-Pacific region means that the geographic and genetic scope of many species’ data sets are not complementary. Here, we describe data sets from 116 Indo-Pacific species (108 studies). With a mind to future synthetic investigations, we consider the strengths and omissions of currently published population genetic data for marine fauna of the Indo-Pacific region, as well as the geographic and taxonomic scope of the data, and suggest some ways forward for data collection and collation

Temporal and spatial changes in cartilage-matrix-specific gene expression in mesenchymal stem cells in response to dynamic compression.

Various forms of mechanical stimulation have been shown to enhance chondrogenesis of mesenchymal stem cells (MSCs). However, the response of MSCs undergoing chondrogenesis to such signals has been shown to depend on the temporal application of loading. The objective of this study was to determine the effect of dynamic compression on cartilage-matrix-specific gene expression and to relate this response to the local biochemical environment and cell phenotype at the time of loading. At 0, 7, 14, and 21 days extracellular matrix (ECM) deposition within MSC-seeded agarose hydrogels due to transforming growth factor-β3 stimulation was determined biochemically and histologically, and then reverse transcription-polymerase chain reaction was used to examine the effects of dynamic compression on cartilage-matrix-specific gene expression. The results of these experiments show that the local environment in the core of the constructs is more favorable for chondrogenesis in comparison to the annulus, as evident from both ECM synthesis and gene expression. Additionally, we found that the response of the cells to mechanical stimulus varied with both the spatial region within the constructs and the temporal application of loading. Dynamic compression applied at day 21 was found to enhance levels of cartilage matrix gene expression following a peak in expression levels at day 14 in free swelling constructs, suggesting that mechanical signals play a key role in the maintenance of a chondrogenic phenotype. The application of mechanical stimulus to enhance cartilage ECM synthesis may be an important tool in regenerative medicine-based cartilage repair. The results of this study suggest that a chondrogenic phenotype and/or a well-developed pericellular matrix must first be established before dynamic compression can have a positive effect on cartilage-matrix-specific gene expression

FAPRI 2005 World Agricultural Outlook Briefing Book

none available

Optimal Hypercontractivity for Fermi Fields and Related Non-Commutative Integration

Optimal hypercontractivity bounds for the fermion oscillator semigroup are obtained. These are the fermion analogs of the optimal hypercontractivity bounds for the boson oscillator semigroup obtained by Nelson. In the process, several results of independent interest in the theory of non-commutative integration are established. {}.Comment: 18 p., princeton/ecel/7-12-9

miR-196b target screen reveals mechanisms maintaining leukemia stemness with therapeutic potential.

We have shown that antagomiR inhibition of miRNA miR-21 and miR-196b activity is sufficient to ablate MLL-AF9 leukemia stem cells (LSC) in vivo. Here, we used an shRNA screening approach to mimic miRNA activity on experimentally verified miR-196b targets to identify functionally important and therapeutically relevant pathways downstream of oncogenic miRNA in MLL-r AML. We found Cdkn1b (p27Kip1) is a direct miR-196b target whose repression enhanced an embryonic stem cell–like signature associated with decreased leukemia latency and increased numbers of leukemia stem cells in vivo. Conversely, elevation of p27Kip1 significantly reduced MLL-r leukemia self-renewal, promoted monocytic differentiation of leukemic blasts, and induced cell death. Antagonism of miR-196b activity or pharmacologic inhibition of the Cks1-Skp2–containing SCF E3-ubiquitin ligase complex increased p27Kip1 and inhibited human AML growth. This work illustrates that understanding oncogenic miRNA target pathways can identify actionable targets in leukemia

Plate-style recuperator for a solar Brayton cycle using high-temperature sealant

A large, efficient recuperator is required for high cycle efficiency in a solar Brayton cycle (STBC) with an open-cavity solar receiver and air as working fluid. A recuperator often requires complex and costly manufacturing methods. In this work, a clamped plate-type recuperator with a metal gasket is investigated, together with a low-cost high-temperature sodium silicate-based sealant. Experimental investigations were performed to validate a mathematical model using a novel bone-shape design as well as a wide-channel design. The high-temperature sealant worked well on the bone-shape recuperator; however, a leak occurred on the hot-side header tube of the wide-channel recuperator. For the recuperator core of the wide-channel test rig, a cold-side effectiveness of 82.5% and a total pressure loss of 24.9 kPa were found at an average mass flow rate of 0.74 g/s per channel. The validated mathematical model was used in a parametric study to analyse the performance of the recuperator in an STBC by taking the stress and deflection of the plates into consideration. Results show that, for a total mass flow rate of 0.06 kg/s, a cold-side effectiveness of 90% and total pressure loss of less than 5% could be achieved, if a spacer is implemented to prevent deflection.The National Research Foundation (NRF) of South Africa, the Technology Innovation Agency (TIA) of South Africa, the Department of Science and Innovation (DSI) of South Africa and the University of Pretoria’s Research and Development Plan (RDP).https://www.elsevier.com/locate/apthermeng2021-08-01hj2020Mechanical and Aeronautical Engineerin

Propulsion in a viscoelastic fluid

Flagella beating in complex fluids are significantly influenced by viscoelastic stresses. Relevant examples include the ciliary transport of respiratory airway mucus and the motion of spermatozoa in the mucus-filled female reproductive tract. We consider the simplest model of such propulsion and transport in a complex fluid, a waving sheet of small amplitude free to move in a polymeric fluid with a single relaxation time. We show that, compared to self-propulsion in a Newtonian fluid occurring at a velocity U_N, the sheet swims (or transports fluid) with velocity U / U_N = [1+De^2 (eta_s)/(eta) ]/[1+De^2], where eta_s is the viscosity of the Newtonian solvent, eta is the zero-shear-rate viscosity of the polymeric fluid, and De is the Deborah number for the wave motion, product of the wave frequency by the fluid relaxation time. Similar expressions are derived for the rate of work of the sheet and the mechanical efficiency of the motion. These results are shown to be independent of the particular nonlinear constitutive equations chosen for the fluid, and are valid for both waves of tangential and normal motion. The generalization to more than one relaxation time is also provided. In stark contrast with the Newtonian case, these calculations suggest that transport and locomotion in a non-Newtonian fluid can be conveniently tuned without having to modify the waving gait of the sheet but instead by passively modulating the material properties of the liquid.Comment: 21 pages, 1 figur

The Nature of Infrared Emission in the Local Group Dwarf Galaxy NGC 6822 As Revealed by Spitzer

We present Spitzer imaging of the metal-deficient (Z ~30% Z_sun) Local Group dwarf galaxy NGC 6822. On spatial scales of ~130 pc, we study the nature of IR, H alpha, HI, and radio continuum emission. Nebular emission strength correlates with IR surface brightness; however, roughly half of the IR emission is associated with diffuse regions not luminous at H alpha (as found in previous studies). The global ratio of dust to HI gas in the ISM, while uncertain at the factor of ~2 level, is ~25 times lower than the global values derived for spiral galaxies using similar modeling techniques; localized ratios of dust to HI gas are about a factor of five higher than the global value in NGC 6822. There are strong variations (factors of ~10) in the relative ratios of H alpha and IR flux throughout the central disk; the low dust content of NGC 6822 is likely responsible for the different H alpha/IR ratios compared to those found in more metal-rich environments. The H alpha and IR emission is associated with high-column density (> ~1E21 cm^-2) neutral gas. Increases in IR surface brightness appear to be affected by both increased radiation field strength and increased local gas density. Individual regions and the galaxy as a whole fall within the observed scatter of recent high-resolution studies of the radio-far IR correlation in nearby spiral galaxies; this is likely the result of depleted radio and far-IR emission strengths in the ISM of this dwarf galaxy.Comment: ApJ, in press; please retrieve full-resolution version from http://www.astro.wesleyan.edu/~cannon/pubs.htm