We present mid-infrared Stratospheric Observatory for Infrared Astronomy (SOFIA)/Echelon Cross Echelle Spectrograph (EXES) spectroscopy of Europa, seeking direct evidence of the presence of water ...vapor arising from plumes venting from the surface. We place quantitatively useful upper limits on the strength of water vibrational-rotational emission lines. Conversion to water mass limits is dependent on the rotational temperature of the vapor. For low rotational temperature, the limits lie below the inferred water mass from previous Hubble Space Telescope (HST) plume observations. For higher temperatures, the limits are comparable. We also present coordinated HST transit observations obtained close in time to the SOFIA observations. There is evidence for a feature close to the location of the previously seen feature north of the crater Pwyll in one of the HST images, although it was not observable by EXES given its location. We conclude that if a water plume had been active at the time of the SOFIA observation, with the strength implied by previous HST observations, then under the right Earth atmospheric and geometric conditions, the plume could have been detected by EXES; however, no infrared water vibrational-rotational emission was detected.
In this study, we report the complete mitochondrial genome or mitogenome of the blister beetle Hycleus scutellatus, one endemic species from the Iberian Peninsula. The mitogenome was 16,035 base ...pairs in length, with an A + T content of 71.7%. It has 37 genes including 13 protein-coding genes, 22 transfer RNA genes and 2 ribosomal RNA genes. To analyze the evolutionary position of H. scutellatus, we constructed a phylogenetic tree using all available mitogenomes from species of the family Meloidae. The results show that Hycleus species are very close to the genus Mylabris. We present here the mitogenome of H. scutellatus as a new resource to elucidate the phylogenetic relations among the Meloidea family, being this source very useful for future evolutionary analyses of blister beetles.
•A novel technology recently patented was developed to extract Persistent Organic Pollutants (POPs) from airborne particulate matter.•The technology was efficient and reproducible to determine POPs ...in particulate matter.•UAE-MSC was applied to determine POPs in PM2.5 of Mexico City.•UAE-MSC extracts, filters, collects the sample, and evaporates the solvent, on-line.•UAE-MSC decrease time, energy, solvent consumption, waste generation and costs.
New clean technologies are needed to determine concentration of organic pollutants without generating more pollution. A method to extract Persistent Organic Pollutants (POPs) from airborne particulate matter was developed using a novel technology recently patented called ultrasound assisted extraction micro-scale cell (UAE-MSC). This technology extracts, filters, collects the sample, and evaporates the solvent, on-line. No sample transfer is needed. The cell minimizes sample manipulation, solvent consumption, waste generation, time, and energy; fulfilling most of the analytical green chemistry protocol. The methodology was optimized applying a centred 23 factorial experimental design. Optimum conditions were used to validate and determine concentration of 16 organochlorine pesticides (OCls) and 6 polybrominated diphenyl ethers (PBDEs). The best conditions achieved were 2 extractions with 5mL (each) of dichloromethane over 5min (each) at 60°C and 80% ultrasound potency. POPs were determined by gas chromatography/mass spectrometry in negative chemical ionization (GC/MS-NCI). Analytical method validation was carried out on airborne particles spiked with POPs at seven concentration levels between 0.5 and 26.9pgm−3. This procedure was done by triplicate (N=21). Recovery, ranged between 65.5±2.3% and 107.5±3.0% for OCls and between 79.1±6.5% and 105.2±3.8% for PBDEs. Linearity (r2) was ≥0.94 for all compounds. Method detection limits, ranged from 0.5 to 2.7pgm−3, while limits of quantification (LOQ), ranged from 1.7 to 9.0pgm−3. A Bias from −18.6% to 9% for PBDEs was observed in the Standard Reference Material (SRM) 2787. SRM 2787 did not contain OCls. OCls recoveries were equivalent by UAE-MSC and Soxhlet methods UAE-MSC optimized extraction conditions reduced 30 times less solvent and decreased the extraction time from several hours to ten minutes, respect to Soxhlet. UAE-MSC was applied to 15 samples of particles less than 2.5μm (PM2.5) from three seasons (warm dry, rainy, and cold dry) collected in five sites around Mexico City. OCls (4,4′-DDE and endrin aldehyde) concentrations ranged from <LOQ to 12.6pgm−3, while PBDEs levels were below the quantification limit, although BDE-99 was detected in all samples. UAE-MSC is a novel technology to determine organic compounds present in trace concentrations in particulate matter. This technology can be extended to extract organic compounds in different solid matrices to minimize time extraction and solvent consumption.
Heterogeneous photocatalysis is a highly efficient process for degrading recalcitrant and emerging pollutants. Rhodamine B (RhB) is a nonbiodegradable and highly refractory compound persistent in ...conventional processes. In this work, we investigate the photocatalytic activity of gallium-based catalysts undoped (GO) and doped with Fe ions (GOFe). Catalysts were synthesized by simple precipitation assisted with an ultrasonic transducer and subjected to thermal treatment at different temperatures (500, 650, 800 and 950°C). They were characterized by thermogravimetric analysis (TGA), Fourier transform infrared (ATR-FTIR) spectroscopy, and X-ray diffraction (XRD). Catalysts were tested in the discoloration of Rhodamine B dye. Experiments were carried out at different pH values (3.00, 5.00 and 9.00) in the presence of H
2
O
2
and using Visible and Visible-UV light sources as study variables. Better discoloration results were observed for GO and GOFe under acid environments (
pH
= 3.00) for both light sources. GO and GOFe photocatalyst showed high effectiveness in the discoloration of RhB completing the process in 300 min, under a Visible-UV lamp at
pH
= 3.00. Incorporating Fe ions into the gallium oxides matrix decreases its bandgap, allowing it to activate under visible light. The discoloration process exhibited pseudo-zero-order apparent kinetics.
We characterize the dust in NGC 628 and NGC 6946, two nearby spiral galaxies in the KINGFISH sample. With data from 3.6 mu m to 500 mu m, dust models are strongly constrained. Using the Draine & Li ...dust model (amorphous silicate and carbonaceous grains), for each pixel in each galaxy we estimate (1) dust mass surface density, (2) dust mass fraction contributed by polycyclic aromatic hydrocarbons, (3) distribution of starlight intensities heating the dust, (4) total infrared (IR) luminosity emitted by the dust, and (5) IR luminosity originating in regions with high starlight intensity. We obtain maps for the dust properties, which trace the spiral structure of the galaxies. The dust models successfully reproduce the observed global and resolved spectral energy distributions (SEDs). The overall dust/H mass ratio is estimated to be 0.0082 + or - 0.0017 for NGC 628, and 0.0063 + or - 0.0009 for NGC 6946, consistent with what is expected for galaxies of near-solar metallicity. Our derived dust masses are larger (by up to a factor of three) than estimates based on single-temperature modified blackbody fits. We show that the SED fits are significantly improved if the starlight intensity distribution includes a (single intensity) "delta function" component. We find no evidence for significant masses of cold dust (T <, ~ 12 K). Discrepancies between PACS and MIPS photometry in both low and high surface brightness areas result in large uncertainties when the modeling is done at PACS resolutions, in which case SPIRE, MIPS70, and MIPS160 data cannot be used. We recommend against attempting to model dust at the angular resolution of PACS.
We report an experimental study of switchable rectangular pulses generation in a passively mode-locked double-clad thulium-doped fiber laser operating in the anomalous dispersion regime. A fiber loop ...mirror and a polarization imbalanced nonlinear optical loop mirror (NOLM) forms the linear cavity. The loop in the NOLM includes a quarter-wave retarder, which allows switching between two regimes of rectangular pulse generation. The laser generates rectangular noise-like pulses (NLPs) or dissipative soliton resonance (DSR) pulses with 1.18 MHz repetition rate at ∼1990 nm. At the maximum pump power of 10 W, rectangular pulses with energy of up to 540 nJ in DSR operation and 482 nJ in NLP operation were obtained with output average power of 640 mW and 571 mW, respectively.
Understanding the evolution and regulation of nucleolar organizing regions (NORs) is important to elucidate genome structure and function. This is because ribosomal gene (rDNA) copy number and ...activity mediate protein biosynthesis, stress response, ageing, disease, dosage compensation and genome stability. Here, we found contrasting dosage compensation of sex‐linked NORs in turtles with male and female heterogamety. Most taxa examined exhibit homomorphic rRNA gene clusters in a single autosome pair (determined by 28S rDNA fluorescence in situ hybridization), whereas NORs are sex‐linked in Apalone spinifera, Pelodiscus sinensis and Staurotypus triporcatus. Full‐dosage compensation upregulates the male X‐NOR (determined via silver staining—AgNOR) in Staurotypus (who lacks Y‐NOR) compared with female X‐AgNORs. In softshell Apalone and Pelodiscus, who share homologous ZZ/ZW micro‐chromosomes, their enlarged W‐NOR is partially active (due to 28S rDNA invasion by R2 retroelements), whereas their smaller Z‐NOR is silent in females but active in both male‐Zs (presumably because the W‐NOR meets cellular demands and excessive NOR activity is costly). We hypothesize that R2 disruption favoured W enlargement to add intact 28S‐units, perhaps facilitated by reduced recombination during sex chromosome evolution. The molecular basis of the potentially adaptive female Z‐silencing is likely intricate and perhaps epigenetic, as non‐ribosomal Z genes are active in Apalone females. Yet, Emydura maquarii exhibit identical heteromorphism in their autosomal NOR (R2 invaded 28S‐units and the small‐autosome NOR is silent), suggesting that the softshell turtle pattern can evolve independent of sex chromosome evolution. Our study illuminates the complex sex chromosome evolution and dosage compensation of non‐model systems that challenges classic paradigms.
Nucleolar organizing regions (NORs) that are sex‐linked in turtles are dimorphic in size and activity. These sexually dimorphic NORs are compensated by simple upregulation in hemizygous male‐X of Staurotypus, as in Drosophila. In female softshell turtles (Apalone and Pelodiscus), NOR dossage compensation occurs by partial W‐NOR and full Z‐NOR silencing, resembling an autosomal‐NOR pattern in unrelated turtles (Emydura).
Abstract
We present a simple and efficient experimental approach to synchronized dual-wavelength pulsed operation in an all-fiber laser. Four different dual-wavelength emissions of synchronized ...picosecond pulses are generated through simple adjustments of a wave retarder. Autocorrelation traces exhibit modulation profiles corresponding to dual-wavelength emissions with wavelength separations ranging over one order of magnitude, from 0.96 to 9 nm. In all cases, it is observed stable dual-wavelength operation and perfect synchronization between both pulsed components, without requiring of intra-cavity dispersion management. For the first time, to the best of our knowledge, synchronous tunable dual-wavelength pulse emission in a single-cavity Er/Yb double clad ring fiber laser is experimentally demonstrated.
Recent sequencing and software enhancements have advanced our understanding of the evolution of genomic structure and function, especially addressing novel evolutionary biology questions. Yet ...fragmentary turtle genome assemblies remain a challenge to fully decipher the genetic architecture of adaptive evolution. Here, we use optical mapping to improve the contiguity of the painted turtle (
) genome assembly and use
fluorescent in situ hybridization (FISH) of bacterial artificial chromosome (BAC) clones, BAC-FISH, to physically map the genomes of the painted and slider turtles (
). Optical mapping increased
's N50 by ~242% compared to the previous assembly. Physical mapping permitted anchoring ~45% of the genome assembly, spanning 5544 genes (including 20 genes related to the sex determination network of turtles and vertebrates). BAC-FISH data revealed assembly errors in
and
assemblies, highlighting the importance of molecular cytogenetic data to complement bioinformatic approaches. We also compared
's anchored scaffolds to the genomes of other chelonians, chicken, lizards, and snake. Results revealed a mostly one-to-one correspondence between chromosomes of painted and slider turtles, and high homology among large syntenic blocks shared with other turtles and sauropsids. Yet, numerous chromosomal rearrangements were also evident across chelonians, between turtles and squamates, and between avian and non-avian reptiles.
Low-metallicity galaxies exhibit different properties of the interstellar medium (ISM) compared to nearby spiral galaxies. Obtaining a resolved inventory of the various gas and dust components of ...massive star-forming regions and diffuse ISM is necessary to understand how those differences are driven. We present a study of the infrared/submillimetre (submm) emission of the massive star-forming complex N158-N159-N160 located in the Large Magellanic Cloud (LMC). Combining observations from the Spitzer Space Telescope (3.6-70 μm), the Herschel Space Observatory (100-500 μm) and Large APEX Bolometer Camera (LABOCA) (on Atacama Pathfinder EXperiment, 870 μm) allows us to work at the best angular resolution available now for an extragalactic source (a few parsec for the LMC). We observe a remarkably good correlation between the Herschel Spectral and Photometric Imaging Receiver (SPIRE) and LABOCA emission and resolve the low surface brightnesses emission. We use the Spitzer and Herschel data to perform a resolved spectral energy distribution (SED) modelling of the complex. Using modified blackbodies, we derive an average 'effective' emissivity index of the cold dust component βc of 1.47 across the complex. If βc is fixed to 1.5, we find an average temperature of ∼27 K (maximum of ∼32 K in N160). We also apply the Galliano et al. SED modelling technique (using amorphous carbon to model carbon dust) to derive maps of the star formation rate, the grain temperature, the mean starlight intensity, the fraction of polycyclic aromatic hydrocarbons (PAH) or the dust mass surface density of the region. We observe that the PAH fraction strongly decreases in the H ii regions we study. This decrease coincides with peaks in the mean radiation field intensity map. The dust surface densities follow the far-infrared distribution, with a total dust mass of 2.1 × 104 M (2.8 times less than if carbon dust was modelled by standard graphite grains) in the resolved elements we model. We also find a non-negligible amount of dust in the region called 'N159 South', a molecular cloud that does not show massive star formation. We also investigate the drivers of the Herschel/PACS (Photodetector Array Camera and Spectrometer) and SPIRE submm colours and find that the submm ratios correlate strongly with the radiation field intensity and with the near and mid-IR surface brightnesses equally well. Comparing our dust map to H i and CO observations in N159, we then investigate variations in the gas-to-dust mass ratio (G/D) and the CO-to-H2 conversion factor XCO. A mean value of G/D∼356 is derived when using XCO = 7×1020 H2 cm−2 (K km s−1)−1. If a constant G/D across N159 is assumed, we derive a XCO conversion factor of 5.4×1020 H2 cm−2 (K km s−1)−1. We finally model individual regions to analyse variations in the SED shape across the complex and the 870 μm emission in more details. No measurable submm excess emission at 870 μm seems to be detected in these regions.
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