A 850-GHz waveguide receiver employing a niobium SIS junction fabricated on a 1-μm Si_3N_4 membrane

We report on a 850-GHz superconducting-insulator-superconducting (SIS) heterodyne receiver employing an RF-tuned niobium tunnel junction with a current density of 14 kA/cm^2, fabricated on a 1-µm Si_3N_4 supporting membrane. Since the mixer is designed to be operated well above the superconducting gap frequency of niobium (2Δ/h ≈ 690 GHz), special care has been taken to minimize niobium transmission-line losses. Both Fourier transform spectrometer (FTS) measurements of the direct detection performance and calculations of the IF output noise with the mixer operating in heterodyne mode, indicate an absorption loss in the niobium film of about 6.8 dB at 822 GHz. These results are in reasonably good agreement with the loss predicted by the Mattis-Bardeen theory in the extreme anomalous limit. From 800 to 830 GHz, we report uncorrected receiver noise temperatures of 518 or 514 K when we use Callen and Welton's law to calculate the input load temperatures. Over the same frequency range, the mixer has a 4-dB conversion loss and 265 K ± 10 K noise temperature. At 890 GHz, the sensitivity of the receiver has degraded to 900 K, which is primarily the result of increased niobium film loss in the RF matching network. When the mixer was cooled from 4.2 to 1.9 K, the receiver noise temperature improved about 20% 409-K double sideband (DSB). Approximately half of the receiver noise temperature improvement can be attributed to a lower mixer conversion loss, while the remainder is due to a reduction in the niobium film absorption loss. At 982 GHz, we measured a receiver noise temperature of 1916 K

Evapotranspiration Rates of Three Sweet Corn Cultivars under Different Irrigation Levels

Understanding plants’ response to different irrigation levels is essential for developing effective irrigation scheduling practices that conserve water without affecting plant growth and yield. The objective of this study was to evaluate the responses of three sweet corn (Zea mays var. saccharata) cultivars 1170, 8021, and Battalion under three irrigation levels (50%, 75%, and 100%). Irrigation treatments were based on soil moisture management allowable depletion. Replicated trials were conducted, in an open field using 1-gal containers, at the Tropical Research and Education Center, Homestead, FL. A drip system with microsprinklers was used for irrigation. Daily crop evapotranspiration (ETc) rates were measured using a digital scale based on differences in weights of soil containers and plants. Reference evapotranspiration (ETo) was calculated using the FAO-Penman-Monteith equation. Crop-coefficient (Kc) values for the three cultivars were calculated from measured ETc and calculated ETo. In addition, leaf area, stomatal conductance, and fresh biomass were measured. Total irrigation amounts corresponding to the 50%, 75%, and 100% treatments were 116, 162, and 216 mm, and total ETc values were 128, 157, and 170 mm, respectively. The two deficit irrigation treatments (50% and 75%) resulted in a reduction of ETc for the three cultivars compared with the 100% irrigation treatments. Results also showed that under 75% and 100% treatments, Kc values were usually greater than 1 for the three cultivars and reached as high as 1.5. Additionally, leaf area and fresh biomass weight in the 50% treatment were mostly lower than in the 75% or 100% treatments

Effect of the soil water-to-air ratio on water status, leaf gas exchange and biomass of avocado trees

ABSTRACT Avocado (Persea americana Mill.) is one of the most sensitive fruit tree species to flooded or poorly drained soil conditions. In Chile, avocado orchards are often planted in poorly drained soils that are low in oxygen resulting in tree stress. Understanding the relationship between the water-to-air ratio of different soils and avocado tree physiology and growth, should be helpful for irrigation management of the crop. The objective of this study was to relate the water-to-air ratios in different soils to water status, leaf gas exchange and biomass of avocado trees. Avocado trees were grown in each of five soils each collected from a different area of the Chilean avocado growing region with different physical properties and hence different water to air ratios. Thus, there were five treatments (T1-T5) corresponding to each of the five soils. The experiment was conducted during the spring and summer of 2005-2006 and 2006-2007 starting with two-year-old 'Hass' avocado trees planted outdoors in containers filled with one of the five soil treatments. At field capacity, the two-season average soil water-to-air ratio (W/A) was 1.7, 1.3, 0.6, 0.4 or 0.3 for treatments T1, T2, T3, T4, or T5, respectively. In addition to determining soil physical characteristics and monitoring W/A, net CO2 assimilation (A), transpiration (Tr), stomatal conductance (gs), stem water potential (SWP), shoot and root fresh and dry weights, leaf area and leaf retention were evaluated for trees in each treatment. Although aerobic soil conditions were maintained in all treatments, trees in soil with lower W/A had higher A, Tr, gs, and SWP than trees in the treatments with higher W/A. Also, trees in treatments with lower W/A had more biomass and longer leaf retention than trees in treatments with higher W/A. The results of this study indicate that the soil water-to-air ratio significantly affects physiology and growth of 'Hass' avocado trees. Efecto de la relación agua/ aire del suelo en el estatus hídrico, intercambio gaseosos de la hoja y biomasa de paltos. Pilar M. Gil, Raúl Ferreyra, Bruce Schaffer, Cristián Barrera, José M. Celedón, Patricio Maldonado, Carlos Zúñiga, Cristóbal Gentina y Luis Gurovich RESUMEN El palto o aguacate (Persea americana Mill.) es una de las especies más sensible al anegamientoo condiciones de pobre drenaje del suelo. En Chile, los huertos de palto son a menudo plantados en suelos de pobre drenaje que son pobres en oxígeno lo que provoca estrés en los árboles. Entendiendo cómo se relaciona una característica del suelo tal como la relación agua/aire en diferentes tipos de suelo, y la fisiología y crecimiento del palto, podría ser una información importante para determinar el manejo de riego de este cultivo. El objetivo de este estudio fue relacionar la relación agua/aire del suelo en diferentes suelos con el estatus hídrico, intercambio gaseoso y biomasa de árboles de palto. Árboles de palto fueron establecidos en uno de cinco tipos de suelo recolectados desde diferentes zonas de la región de cultivo del palto; cada suelo tenía diferentes propiedades físicas y por tanto diferente relación agua/aire. Por tanto, se aplicaron 5 tratamientos, (T1-T5) correspondientes a cada uno de los 5 suelos. El experimento se condujo durante la primavera capacidad de campo, el promedio relación agua/aire (W/A) de ambas temporadas fue de 1.7, 1.3, 0.6, 0.4 o 0.3 para los tratamientos T1, T2, T3, T4, o T5, respectivamente. Además de determinar las características físicas del suelo y monitorear W/A, se determinó la asimilación neta de CO2 (A), transpiración (Tr), conductancia estomática (gs), potencial hídrico xilemático (SWP), peso seco y fresco de brotes y raíces, área foliar y retención de hojas. Aunque las condiciones del suelo se mantuvieron como aeróbicas en todos los tratamientos, los árboles en suelo con baja relación tuvieron mejores valores de A, Tr, gs, y SWP que árboles en tratamientos con alta relación W/A. También, los árboles en tratamientos con menor W/A tuvieron más biomasa, área foliar y mayor retención de hojas que árboles desarrollados en suelos con mayor W/A. Los resultados de este estudio indican que la relación agua/aire del suelo afectan significativamente la fisiología y crecimiento de paltos cv. 'Hass'

The IUPHAR/BPS Guide to PHARMACOLOGY in 2018: updates and expansion to encompass the new guide to IMMUNOPHARMACOLOGY.

The IUPHAR/BPS Guide to PHARMACOLOGY (GtoPdb, www.guidetopharmacology.org) and its precursor IUPHAR-DB, have captured expert-curated interactions between targets and ligands from selected papers in pharmacology and drug discovery since 2003. This resource continues to be developed in conjunction with the International Union of Basic and Clinical Pharmacology (IUPHAR) and the British Pharmacological Society (BPS). As previously described, our unique model of content selection and quality control is based on 96 target-class subcommittees comprising 512 scientists collaborating with in-house curators. This update describes content expansion, new features and interoperability improvements introduced in the 10 releases since August 2015. Our relationship matrix now describes ∼9000 ligands, ∼15 000 binding constants, ∼6000 papers and ∼1700 human proteins. As an important addition, we also introduce our newly funded project for the Guide to IMMUNOPHARMACOLOGY (GtoImmuPdb, www.guidetoimmunopharmacology.org). This has been 'forked' from the well-established GtoPdb data model and expanded into new types of data related to the immune system and inflammatory processes. This includes new ligands, targets, pathways, cell types and diseases for which we are recruiting new IUPHAR expert committees. Designed as an immunopharmacological gateway, it also has an emphasis on potential therapeutic interventions

Intramuscular Lipid Metabolism, Insulin Action and Obesity

With the increasing prevalence of obesity, research has focused on the molecular mechanism(s) linking obesity and skeletal muscle insulin resistance. Metabolic alterations within muscle, such as changes in the cellular location of fatty acid transporter proteins, decreased mitochondrial enzyme activity and defects in mitochondrial morphology, likely contribute to obesity and insulin resistance. These defects are thought to play a role in the reduced skeletal muscle fatty acid oxidation (FAO) and increased intramuscular lipid (IMCL) accumulation that is apparent with obesity and other insulin resistant states, such as type 2 diabetes. Intramuscular triacylglycerol (IMTG) does not appear to be a ubiquitous marker of insulin resistance, although specific IMCL intermediates such as long-chain fatty acyl-CoAs (LCFA-CoAs), ceramide and diacylglycerol (DAG) may inhibit insulin signal transduction. In this review, we will briefly summarize the defects in skeletal muscle lipid metabolism associated with obesity, and discuss proposed mechanisms by which these defects may contribute to insulin resistance. Originally published IUBMB Life, Vol. 6, No. 1, Jan 200

The Atacama Cosmology Telescope: Data Characterization and Map Making

We present a description of the data reduction and mapmaking pipeline used for the 2008 observing season of the Atacama Cosmology Telescope (ACT). The data presented here at 148 GHz represent 12% of the 90 TB collected by ACT from 2007 to 2010. In 2008 we observed for 136 days, producing a total of 1423 hours of data (11 TB for the 148 GHz band only), with a daily average of 10.5 hours of observation. From these, 1085 hours were devoted to a 850 deg^2 stripe (11.2 hours by 9.1 deg) centered on a declination of -52.7 deg, while 175 hours were devoted to a 280 deg^2 stripe (4.5 hours by 4.8 deg) centered at the celestial equator. We discuss sources of statistical and systematic noise, calibration, telescope pointing, and data selection. Out of 1260 survey hours and 1024 detectors per array, 816 hours and 593 effective detectors remain after data selection for this frequency band, yielding a 38% survey efficiency. The total sensitivity in 2008, determined from the noise level between 5 Hz and 20 Hz in the time-ordered data stream (TOD), is 32 micro-Kelvin sqrt{s} in CMB units. Atmospheric brightness fluctuations constitute the main contaminant in the data and dominate the detector noise covariance at low frequencies in the TOD. The maps were made by solving the least-squares problem using the Preconditioned Conjugate Gradient method, incorporating the details of the detector and noise correlations. Cross-correlation with WMAP sky maps, as well as analysis from simulations, reveal that our maps are unbiased at multipoles ell > 300. This paper accompanies the public release of the 148 GHz southern stripe maps from 2008. The techniques described here will be applied to future maps and data releases.Comment: 20 pages, 18 figures, 6 tables, an ACT Collaboration pape

Multivalent glycoconjugates as anti-pathogenic agents

Multivalency plays a major role in biological processes and particularly in the relationship between pathogenic microorganisms and their host that involves protein–glycan recognition. These interactions occur during the first steps of infection, for specific recognition between host and bacteria, but also at different stages of the immune response. The search for high-affinity ligands for studying such interactions involves the combination of carbohydrate head groups with different scaffolds and linkers generating multivalent glycocompounds with controlled spatial and topology parameters. By interfering with pathogen adhesion, such glycocompounds including glycopolymers, glycoclusters, glycodendrimers and glyconanoparticles have the potential to improve or replace antibiotic treatments that are now subverted by resistance. Multivalent glycoconjugates have also been used for stimulating the innate and adaptive immune systems, for example with carbohydrate-based vaccines. Bacteria present on their surfaces natural multivalent glycoconjugates such as lipopolysaccharides and S-layers that can also be exploited or targeted in anti-infectious strategie

Microwave heating, isothermal sintering, and mechanical properties of powder metallurgy titanium and titanium alloys

This article presents a detailed assessment of microwave (MW) heating, isothermal sintering, and the resulting tensile properties of commercially pure Ti (CP-Ti), Ti-6Al-4V, and Ti-10V-2Fe-3Al (wt pct), by comparison with those fabricated by conventional vacuum sintering. The potential of MW sintering for titanium fabrication is evaluated accordingly. Pure MW radiation is capable of heating titanium powder to ≥1573 K (1300 C), but the heating response is erratic and difficult to reproduce. In contrast, the use of SiC MW susceptors ensures rapid, consistent, and controllable MW heating of titanium powder. MW sintering can consolidate CP-Ti and Ti alloys compacted from -100 mesh hydride-dehydride (HDH) Ti powder to ~95.0 pct theoretical density (TD) at 1573 K (1300 C), but no accelerated isothermal sintering has been observed over conventional practice. Significant interstitial contamination occurred from the Al2O3-SiC insulation-susceptor package, despite the high vacuum used (≤4.0 × 10-3 Pa). This leads to erratic mechanical properties including poor tensile ductility. The use of Ti sponge as impurity (O, N, C, and Si) absorbers can effectively eliminate this problem and ensure good-to-excellent tensile properties for MW-sintered CP-Ti, Ti-10V-2Fe-3Al, and Ti-6Al-4V. The mechanisms behind various observations are discussed. The prime benefit of MW sintering of Ti powder is rapid heating. MW sintering of Ti powder is suitable for the fabrication of small titanium parts or titanium preforms for subsequent thermomechanical processing