1,383 research outputs found
Not all jellyfish are equal: isotopic evidence for inter- and intraspecific variation in jellyfish trophic ecology
Jellyfish are highly topical within studies of pelagic food-webs and there is a growing realisation that their role is more complex than once thought. Efforts being made to include jellyfish within fisheries and ecosystem models are an important step forward, but our present understanding of their underlying trophic ecology can lead to their oversimplification in these models. Gelatinous zooplankton represent a polyphyletic assemblage spanning >2,000 species that inhabit coastal seas to the deep-ocean and employ a wide variety of foraging strategies. Despite this diversity, many contemporary modelling approaches include jellyfish as a single functional group feeding at one or two trophic levels at most. Recent reviews have drawn attention to this issue and highlighted the need for improved communication between biologists and theoreticians if this problem is to be overcome. We used stable isotopes to investigate the trophic ecology of three co-occurring scyphozoan jellyfish species (Aurelia aurita, Cyanea lamarckii and C. capillata) within a temperate, coastal food-web in the NE Atlantic. Using information on individual size, time of year and δ 13 C and δ 15 N stable isotope values, we examined: (1) whether all jellyfish could be considered as a single functional group, or showed distinct inter-specific differences in trophic ecology; (2) Were size-based shifts in trophic position, found previously in A. aurita, a common trait across species?; (3) When considered collectively, did the trophic position of three sympatric species remain constant over time? Differences in δ 15 N (trophic position) were evident between all three species, with size-based and temporal shifts in δ 15 N apparent in A. aurita and C. capillata. The isotopic niche width for all species combined increased throughout the season, reflecting temporal shifts in trophic position and seasonal succession in these gelatinous species. Taken together, these findings support previous assertions that jellyfish require more robust inclusion in marine fisheries or ecosystem models
Development of an Experimental Waste Framework Based on Bim/Lean Concept in Construction Design
The construction industry faces many problems and challenges especially with the construction of housing which are due to the high level of non-value-adding activities (waste) that reduce the overall construction performance and productivity. In recent years, there have been investigations and research on improving the performance of construction. Lean construction is widely known as an effective process which aims to maximise customer value and the efficiency of the project by eliminating non-value-adding activities or waste. Moreover, the Building Information modelling (BIM) concept has been recognised as a collaborative process which aims to improve the overall project performance through its tools' capabilities. This paper intends to study the potential effects of integrating these two concepts in order to reduce construction waste. This paper presents a framework, named an Experimental Waste Framework based on the findings of this paper to explore how an integrated BIM and Lean concept can contribute to the practicable reduction of construction waste in the design process of construction
Sensing and Active Flow Control for Advanced BWB Propulsion-Airframe Integration Concepts
In order to realize the substantial performance benefits of serpentine boundary layer ingesting diffusers, this study investigated the use of enabling flow control methods to reduce engine-face flow distortion. Computational methods and novel flow control modeling techniques were utilized that allowed for rapid, accurate analysis of flow control geometries. Results were validated experimentally using the Techsburg Ejector-based wind tunnel facility; this facility is capable of simulating the high-altitude, high subsonic Mach number conditions representative of BWB cruise conditions
Metastatic recurrence in a pancreatic cancer patient derived orthotopic xenograft (PDOX) nude mouse model is inhibited by neoadjuvant chemotherapy in combination with fluorescence-guided surgery with an anti-CA 19-9-conjugated fluorophore.
The aim of this study is to determine the efficacy of neoadjuvant chemotherapy (NAC) with gemcitabine (GEM) in combination with fluorescence-guided surgery (FGS) on a pancreatic cancer patient derived orthotopic xenograft (PDOX) model. A PDOX model was established from a CA19-9-positive, CEA-negative tumor from a patient who had undergone a pancreaticoduodenectomy for pancreatic adenocarcinoma. Mice were randomized to 4 groups: bright light surgery (BLS) only; BLS+NAC; FGS only; and FGS+NAC. An anti-CA19-9 or anti-CEA antibody conjugated to DyLight 650 was administered intravenously via the tail vein of mice with the pancreatic cancer PDOX 24 hours before surgery. The PDOX was brightly labeled with fluorophore-conjugated anti-CA19-9, but not with a fluorophore-conjugated anti-CEA antibody. FGS was performed using the fluorophore-conjugated anti-CA19-9 antibody. FGS had no benefit over BLS to prevent metastatic recurrence. NAC in combination with BLS did not convey an advantage over BLS to prevent metastatic recurrence. However, FGS+NAC significantly reduced the metastatic recurrence frequency to one of 8 mice, compared to FGS only after which metastasis recurred in 6 out of 8 mice, and BLS+NAC with metastatic recurrence in 7 out of 8 mice (p = 0.041). Thus NAC in combination with FGS can reduce or even eliminate metastatic recurrence of pancreatic cancer sensitive to NAC. The present study further emphasizes the power of the PDOX model which enables metastasis to occur and thereby identify the efficacy of NAC in combination with FGS on metastatic recurrence
Spitzer and near-infrared observations of a new bi-polar protostellar outflow in the Rosette Molecular Cloud
We present and discuss \emph{Spitzer} and near-infrared H observations
of a new bi-polar protostellar outflow in the Rosette Molecular Cloud. The
outflow is seen in all four IRAC bands and partially as diffuse emission in the
MIPS 24 m band. An embedded MIPS 24 m source bisects the outflow and
appears to be the driving source. This source is coincident with a dark patch
seen in absorption in the 8 m IRAC image. \emph{Spitzer} IRAC color
analysis of the shocked emission was performed from which thermal and column
density maps of the outflow were constructed. Narrow-band near-infrared (NIR)
images of the flow reveal H emission features coincident with the high
temperature regions of the outflow. This outflow has now been given the
designation MHO 1321 due to the detection of NIR H features. We use these
data and maps to probe the physical conditions and structure of the flow.Comment: Accepted for publication in The Astrophysical Journa
Portraying the hosts: Stellar science from planet searches
Information on the full session can be found on this website: https://sites.google.com/site/portrayingthehostscs18/We present a compendium of the splinter session on stellar science from planet searches that was organized as part of the Cool Stars 18 conference. Seven speakers discussed techniques to infer stellar information from radial velocity, transit and microlensing data, as well as new instrumentation and missions designed for planet searches that will provide useful for the study of the cool stars
A novel method for RNA extraction from FFPE samples reveals significant differences in biomarker expression between orthotopic and subcutaneous pancreatic cancer patient-derived xenografts.
Next-generation sequencing (NGS) can identify and validate new biomarkers of cancer onset, progression and therapy resistance. Substantial archives of formalin-fixed, paraffin-embedded (FFPE) cancer samples from patients represent a rich resource for linking molecular signatures to clinical data. However, performing NGS on FFPE samples is limited by poor RNA purification methods. To address this hurdle, we developed an improved methodology for extracting high-quality RNA from FFPE samples. By briefly integrating a newly-designed micro-homogenizing (mH) tool with commercially available FFPE RNA extraction protocols, RNA recovery is increased by approximately 3-fold while maintaining standard A260/A280 ratios and RNA quality index (RQI) values. Furthermore, we demonstrate that the mH-purified FFPE RNAs are longer and of higher integrity. Previous studies have suggested that pancreatic ductal adenocarcinoma (PDAC) gene expression signatures vary significantly under in vitro versus in vivo and in vivo subcutaneous versus orthotopic conditions. By using our improved mH-based method, we were able to preserve established expression patterns of KRas-dependency genes within these three unique microenvironments. Finally, expression analysis of novel biomarkers in KRas mutant PDAC samples revealed that PEAK1 decreases and MST1R increases by over 100-fold in orthotopic versus subcutaneous microenvironments. Interestingly, however, only PEAK1 levels remain elevated in orthotopically grown KRas wild-type PDAC cells. These results demonstrate the critical nature of the orthotopic tumor microenvironment when evaluating the clinical relevance of new biomarkers in cells or patient-derived samples. Furthermore, this new mH-based FFPE RNA extraction method has the potential to enhance and expand future FFPE-RNA-NGS cancer biomarker studies
Laboratory studies of till deformation with implications for the motion and sediment transport of the Lake Michigan Lobe
Glacier motion and sediment transport are attributed commonly to pervasive shearing of subglacial till to high strains (the bed-deformation hypothesis). However, the processes that control bed deformation are difficult to observe beneath modern glaciers, and observations of the geologic record have not been sufficient to determine whether tills have been sheared to the high strains required by this hypothesis;The shear strength of the ice-till interface controls whether a glacier slips over its bed or shears it pervasively over much of its thickness. When clasts gripped by basal ice plow through the bed, the ice-till interface is weakened. Results of experiments using a ring-shear device in which hemispheres were pushed through water-saturated till indicate a progressive decrease in resistive force on hemispheres with increasing plowing speed. This effect is due to the generation of high pore-water pressures in front of the hemispheres at fast plowing speeds (e.g. 380 m y-1), which weakens till and reduces resistive forces. These results indicate that increases in glacier sliding speed will reduce resistive forces exerted by till on plowing clasts, which will promote decoupling of the ice from the bed and inhibit pervasive bed deformation. In addition, this positive pore-pressure feedback may constitute a flow instability that promotes fast glacier flow;The ring-shear device was also used to develop criteria at microscopic scales for identifying highly sheared tills. Results of experiments indicate that the alignment (fabric) of elongate, sand-sized particles becomes strong at high strains. Furthermore, microshears become more abundant and align progressively with the shearing direction as strain increases. Magnetic fabrics calibrated to strain in an ancillary ring-shear study and sand-particle fabrics were used to test the till-deformation model as applied to the Batestown advance of the Lake Michigan Lobe. Results indicate that magnetic and sand-particle fabrics are not sufficiently strong to support the bed-deformation model. Furthermore, consistent changes in fabric direction with depth and fabric patterns around cobbles and small boulders indicate that the till likely sheared only in thin zones near the glacier sole during till accretion to the bed from ice. Bed shearing likely contributed only minimally to sediment transport
Characterizing the Habitable Zones of Exoplanetary Systems with a Large Ultraviolet/Visible/Near-IR Space Observatory
Understanding the surface and atmospheric conditions of Earth-size, rocky
planets in the habitable zones (HZs) of low-mass stars is currently one of the
greatest astronomical endeavors. Knowledge of the planetary effective surface
temperature alone is insufficient to accurately interpret biosignature gases
when they are observed in the coming decades. The UV stellar spectrum drives
and regulates the upper atmospheric heating and chemistry on Earth-like
planets, is critical to the definition and interpretation of biosignature
gases, and may even produce false-positives in our search for biologic
activity. This white paper briefly describes the scientific motivation for
panchromatic observations of exoplanetary systems as a whole (star and planet),
argues that a future NASA UV/Vis/near-IR space observatory is well-suited to
carry out this work, and describes technology development goals that can be
achieved in the next decade to support the development of a UV/Vis/near-IR
flagship mission in the 2020s.Comment: Submitted in response to NASA call for white papers: "Large
Astrophysics Missions to Be Studied by NASA Prior to the 2020 Decadal Survey
Revised Stellar Properties of Kepler Targets for the Quarter 1-16 Transit Detection Run
We present revised properties for 196,468 stars observed by the NASA Kepler
Mission and used in the analysis of Quarter 1-16 (Q1-Q16) data to detect and
characterize transiting exoplanets. The catalog is based on a compilation of
literature values for atmospheric properties (temperature, surface gravity, and
metallicity) derived from different observational techniques (photometry,
spectroscopy, asteroseismology, and exoplanet transits), which were then
homogeneously fitted to a grid of Dartmouth stellar isochrones. We use
broadband photometry and asteroseismology to characterize 11,532 Kepler targets
which were previously unclassified in the Kepler Input Catalog (KIC). We report
the detection of oscillations in 2,762 of these targets, classifying them as
giant stars and increasing the number of known oscillating giant stars observed
by Kepler by ~20% to a total of ~15,500 stars. Typical uncertainties in derived
radii and masses are ~40% and ~20%, respectively, for stars with photometric
constraints only, and 5-15% and ~10% for stars based on spectroscopy and/or
asteroseismology, although these uncertainties vary strongly with spectral type
and luminosity class. A comparison with the Q1-Q12 catalog shows a systematic
decrease in radii for M dwarfs, while radii for K dwarfs decrease or increase
depending on the Q1-Q12 provenance (KIC or Yonsei-Yale isochrones). Radii of
F-G dwarfs are on average unchanged, with the exception of newly identified
giants. The Q1-Q16 star properties catalog is a first step towards an improved
characterization of all Kepler targets to support planet occurrence studies.Comment: 20 pages, 14 figures, 5 tables; accepted for publication in ApJS;
electronic versions of Tables 4 and 5 are available as ancillary files (see
sidebar on the right), and an interactive version of Table 5 is available at
the NASA Exoplanet Archive (http://exoplanetarchive.ipac.caltech.edu/
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