Detection of Coronal Mass Ejections in V471 Tauri with the Hubble Space Telescope

V471 Tauri, an eclipsing system consisting of a hot DA white dwarf (WD) and a dK2 companion in a 12.5-hour orbit, is the prototype of the pre-cataclysmic binaries. The late-type component is magnetically active, due to its being constrained to rotate synchronously with the short orbital period. During a program of UV spectroscopy of V471 Tau, carried out with the Goddard High Resolution Spectrograph (GHRS) onboard the Hubble Space Telescope, we serendipitously detected two episodes in which transient absorptions in the Si III 1206 A resonance line appeared suddenly, on a timescale of <2 min. The observations were taken in a narrow spectral region around Ly-alpha, and were all obtained near the two quadratures of the binary orbit, i.e., at maximum projected separation (~3.3 Rsun) of the WD and K star. We suggest that these transient features arise when coronal mass ejections (CME's) from the K2 dwarf pass across the line of sight to the WD. Estimates of the velocities, densities, and masses of the events in V471 Tau are generally consistent with the properties of solar CME's. Given our detection of 2 events during 6.8 hr of GHRS observing, along with a consideration of the restricted range of latitudes and longitudes on the K star's surface that can give rise to trajectories passing in front of the WD as seen from Earth, we estimate that the active V471 Tau dK star emits some 100-500 CME's per day, as compared to 1-3 per day for the Sun. The K dwarf's mass-loss rate associated with CME's is at least (5-25) x 10^{-14} Msun/yr, but it may well be orders of magnitude higher if most of the silicon is in ionization states other than Si III.Comment: 24 pages AASTeX, 4 figures. Accepted by Astrophysical Journa

Sourcing Flexibility, Spot Trading, and Procurement Contract Structure

We analyze the structure and pricing of option contracts for an industrial good in the presence of spot trading. We combine the analysis of spot trading and buyers' disparate private valuations for different suppliers' products, and we jointly endogenize the determination of three major dimensions in contract design: (i) sales contracts versus options contracts, (ii) flat-price versus volume-dependent contracts, and (iii) volume discounts versus volume premia. We build a model in which a supplier of an industrial good transacts with a manufacturer who uses the supplier's product to produce an end good with an uncertain demand. We show that, consistent with industry observations, volume-dependent optimal sales contracts always demonstrate volume discounts (i.e., involve concave pricing). However, options are more complex agreements, and optimal option contracts can involve both volume discounts and volume premia. Three major contract structures commonly emerge in optimality. First, if the seller has a high discount rate relative to the buyer and the seller's production costs or the production capacity is low, the optimal contracts tend to be flat-price sales contracts. Second, when the seller has a relatively high discount rate compared to the buyer but production costs or production capacity are high, the optimal contracts are sales contracts with volume discounts. Third, if the buyer's discount rate is high relative to the seller's, then the optimal contracts tend to be volume-dependent options contracts and can involve both volume discounts and volume premia. However, when the seller's production capacity is sufficiently low, it is possible to observe flat-price option contracts. Furthermore, we provide links between production and spot market characteristics, contract design, and efficiency.National Science Foundation (U.S.) (contract CMMI-0758069)National Science Foundation (U.S.) (contract DMI-0245352

New Insights into Chloramphenicol Biosynthesis in Streptomyces venezuelae ATCC 10712

Comparative genome analysis revealed seven uncharacterized genes, sven0909 to sven0915, adjacent to the previously identified chloramphenicol biosynthetic gene cluster (sven0916–sven0928) of Streptomyces venezuelae strain ATCC 10712 that was absent in a closely related Streptomyces strain that does not produce chloramphenicol. Transcriptional analysis suggested that three of these genes might be involved in chloramphenicol production, a prediction confirmed by the construction of deletion mutants. These three genes encode a cluster-associated transcriptional activator (Sven0913), a phosphopantetheinyl transferase (Sven0914), and a Na(+)/H(+) antiporter (Sven0915). Bioinformatic analysis also revealed the presence of a previously undetected gene, sven0925, embedded within the chloramphenicol biosynthetic gene cluster that appears to encode an acyl carrier protein, bringing the number of new genes likely to be involved in chloramphenicol production to four. Microarray experiments and synteny comparisons also suggest that sven0929 is part of the biosynthetic gene cluster. This has allowed us to propose an updated and revised version of the chloramphenicol biosynthetic pathway

AMPLON: Amplifying DNA with Multiarm Priming and Looping Optimization of Nucleic Acid

Nucleic acid amplification, the bedrock of biotechnology and molecular diagnostics, surges in applications—especially isothermal approaches—heightening the demand for advanced and precisely engineered methods. Here, a novel approach for amplifying DNA with multiarm priming and looping optimization of nucleic acid (AMPLON) is presented. AMPLON relies on a novel polymeric material with unique set of multiarm polyethylene glycol–DNA primers for efficient DNA amplification under isothermal conditions. Each arm carries single-stranded DNA complementing the sense or antisense sequence of the target DNA. The amplification reaction begins with antisense arms binding to the target DNA, forming a template for sense-carrying arms to direct multiarm large DNA amplicon synthesis through successive DNA looping and unlooping steps. Using human immunodeficiency virus type 1 (HIV-1) as a model clinical target, AMPLON exhibits high sensitivity, detecting target concentrations as low as 100 copies mL−1. Compared to a quantitative real-time polymerase chain reaction assay using sensitive primers, AMPLON reliably identifies HIV-1 RNA in plasma samples (n = 20) with a significant agreement rate of 95%. With its ability to achieve highly specific and sensitive target amplification within 30 min, AMPLON holds immense potential to transform the field of nucleic acid research and unleashing new possibilities in medicine and biotechnology

Is PhoR–PhoP partner fidelity strict? PhoR is required for the activation of the pho regulon in Streptomyces coelicolor

Two-component regulatory systems play a key role in the cell metabolism adaptation to changing nutritional and environmental conditions. The fidelity between the two cognate proteins of a two-component system is important since it determines whether a specific response regulator integrates the signals transmitted by different sensor kinases. Phosphate regulation in Streptomyces coelicolor is mostly mediated by the PhoR–PhoP two-component system. Previous studies elucidated the mechanisms that control phosphate regulation as well as the genes directly regulated by the response regulator PhoP (pho regulon) in this organism. However, the role of the histidine kinase PhoR in Streptomyces coelicolor had not been unveiled so far. In this work, we report the characterization of a non-polar ΔphoR deletion mutant in S. coelicolor that keeps its native promoter. Induction of the phoRP operon was dependent upon phosphorylation of PhoP, but the ΔphoR mutant expressed phoP at a basal level. RT-PCR and reporter luciferase assays demonstrated that PhoR plays a key role in the activation of the pho regulon in this organism. Our results point towards a strict cognate partner specificity in terms of the phosphorylation of PhoP by PhoR thus corroborating the tight interaction between the two-components of this system

Assessment of fishery products consumption behavior: The case of Turkey

From the early history of humanity until today, fish and other fishery products have always been involved in human diet. The intake of a sufficient number of proteins has been enabled through high-quality fish meat containing a significant quantity of essential amino acids as well as omega-3 fatty acids. According to the studies, 150 grams of fish, meets the needs of a 50-60% of daily protein intake for an adult. A large part of fishery production in Turkey (86%), is consumed fresh. Turkey, within the scope of Common Fisheries Policy is trying to harmonize fisheries with the EU. A failure to update the 1380 coded Fisheries Law and rapid issuing of EU compatible regulations, safe food for consumers, high quality products along the year for processing industry and marketers, as well as the inability to ensure sustainable price development for the producers, prevent the success of the sector. The aim of this study was to determine the consumption behavior when taking fishery products in terms of food safety, reliability, product quality as well as the level of income and education

Comparison of selected levels of serum elements / minerals in obese dogs

Obesity is the most common metabolic disorder defined as excessive adipose tissue accumulation in the body. Elements and minerals are crucial for biological metabolism. There have been limited studies based on the relationship between elements/minerals and obesity in dogs. The study was aimed to evaluate possible alterations of selected serum elements/minerals -copper (Cu), iron (Fe), zinc (Zn), selenium (Se), chromium (Cr), nickel (Ni), calcium (Ca), phosphorus (P), magnesium (Mg), boron (B), cobalt (Co) and aluminum (Al)- in obese dogs. The study groups were categorized as obese group (n:20) and controls (n:10) with different breeds and genders due to body condition scoring system cared under similar conditions fed with dry commercial food once daily. Serum elements/minerals in serum were analyzed by using inductively coupled plasma-optical emission spectrophotometer (ICP-OES). Obese dogs had statistically higher serum Fe levels compared with healthy controls. A positive correlation was found between serum levels of Cr-Ni; Cu-Mg; Cu-Se; Mg-Se; Mg-Ca; Mg-P; B-Co; B-Ca; Ni-Co; Co-Ca and Ca-P in obese dogs. It has been accepted that obesity is a pro-inflammatory process priorly initiating in adipose tissue. Higher serum Fe levels in obese dogs might be related with inflammation during the obesity process. Moreover, the strong correlations among other discussed elements/minerals even with no statistical alterations of serum levels in obese dogs should be elucidated with further studies. Elements and minerals might be evaluated as biomarkers for the determination of effects of obesity in dogs

Assessment of Fishery Products Consumption Behavior: the Case of Turkey

From the early history of humanity until today, fish and other fishery products have always been involved in human diet. The intake of a sufficient number of proteins has been enabled through high-quality fish meat containing a significant quantity of essential amino acids as well as omega-3 fatty acids. According to the studies, 150 grams of fish, meets the needs of a 50-60% of daily protein intake for an adult. A large part of fishery production in Turkey (86%), is consumed fresh. Turkey, within the scope of Common Fisheries Policy is trying to harmonize fisheries with the EU. A failure to update the 1380 coded Fisheries Law and rapid issuing of EU compatible regulations, safe food for consumers, high quality products along the year for processing industry and marketers, as well as the inability to ensure sustainable price development for the producers, prevent the success of the sector. The aim of this study was to determine the consumption behavior when taking fishery products in terms of food safety, reliability, product quality as well as the level of income and education