86 research outputs found
The influence of weight and fat on lamb prices revisited
Previous research has found inconsistencies in the valuation of weight and fat characteristics of lamb carcasses between the saleyard and wholesale markets. In this paper, recent New South Wales saleyard and wholesale price data on different classes of lamb are analysed using hedonic methods to determine the relative influence of weight and fat on prices received. Fat score 2 lambs are heavily discounted relative to fat score 3 lambs, and there are significant seasonal price differentials, but there are no significant premiums or discounts for weight or other fat characteristics. These results hold for both the saleyard and wholesale markets. The implication is that the efficiency of price discovery in the Australian lamb market has improved a little in recent years in the sense that premiums and discounts are now consistent across market levels. However consumers’ stated preferences for large lean lambs are not being reflected in price incentives generated in the live lamb and lamb carcass markets.lamb, marketing, hedonic models, carcass characteristics, Demand and Price Analysis, Livestock Production/Industries, Marketing,
X-ray Evaluation of the Marshall Grazing Incidence X-Ray Spectrometer (MaGIXS) Nickel-Replicated Mirrors
X-ray observations of astronomical objects provides diagnostics not available in any other wavelength regime, however the capability of making these observation at a high spatial resolution has proven challenging. Recently, NASA Marshall Space Flight Center (MSFC) has made good progress in employing computer numerical control (CNC) polishing techniques on electroless nickel mandrels as part of our replicated grazing incidence optics program. CNC polishing has afforded the ability to deterministically refine mandrel figure, thereby improving mirror performance. The Marshall Grazing Incidence X-ray Spectrometer (MaGIXS) is a MSFC-led sounding rocket instrument that is designed to make the first ever soft x-ray spectral observations of the Sun spatially resolved along a narrow slit. MaGIXS incorporates some of the first mirrors produced at MSFC using this polishing technique. Here we present the predicted mirror performance obtained from metrology, after completion of CNC polishing, as well as the results of X-ray tests performed on the MaGIXS telescope mirror before and after mounting
Teaching Students about Two-Dimensional Heat Transfer Effects in Buildings, Building Components, Equipment and Appliances using THERM 2.0,
Abstract THERM 2.0 is a state-of-the-art software program, available for free, that uses the finite-element method to model steady-state, two-dimensional heat-transfer effects. It is being used internationally in graduate and undergraduate laboratories and classes as an interactive educational tool to help students gain a better understanding of heat transfer. THERM offers students a powerful simulation engine combined with a simple, interactive interface and graphic results. Although it was developed to model thermal properties of building components such as windows, walls, doors, roofs, and foundations, it is useful for modeling thermal bridges in many other contexts, such as the design of equipment. These capabilities make THERM a useful teaching tool in classes on: heating, ventilation, and air-conditioning (HVAC); energy conservation; building design; and other subjects where heat-transfer theory and applications are important. THERM's state-of-the-art interface and graphic presentation allow students to see heattransfer paths and to learn how changes in materials affect heat transfer. THERM is an excellent tool for helping students understand the practical application of heat-transfer theory
Towards a best practice for the use of active non-contact surface scanning to record human skeletal remains from archaeological contexts
Active surface scanners emit light or a laser stripe to record the exterior surface of an object or landscape, providing results in three dimensions. The use of active surface scanners to record anthropological and archaeological contexts has increased within the last few years, creating a number of sub-contexts within these disciplines, and allowing a further development of certain applications, such as quantitative analysis, the use of replicas in education and museums, and the creation of digital databases archived in institutions. However with guidance, this paper aims to assess the advantages and disadvantages of active surface scanning and the potential for research with regards to the recording and analysis of human skeletal remains. The key advantages and uses identified include: quantitative digitisation, geometric morphometric studies, conservation, preservation, documentation, and reconstruction. However, surface scanning also has some limitations, including: cost, technological expertise, the need for a power source, computing requirements, and data size. Overall, the application of active surface scanning technology to archaeological skeletal remains will provide a vital digital archive that will serve to preserve the integrity of this fragile and finite resource for future generations. This is particularly important within the current developer-funded environment in which many skeletal collections, including those yielding unique or unusual pathological or morphological features, are re-buried, with only very limited time for analysis
X-ray Evaluation of the MaGIXS Nickel-Replicated Mirrors
No abstract availabl
On the Development of the Marshall Grazing Incidence X-ray Spectrograph (MaGIXS) Mirrors
The Marshall Grazing Incidence X-ray Spectrograph (MaGIXS) is a sounding rocket experiment that will obtain spatially resolved soft X-ray spectra of the solar corona from 0.5 - 2 keV. The optical system comprises a Wolter-I telescope mirror, a slit spectrograph, and a CCD camera. The spectrograph has a finite conjugate paraboloid pair, which re-images the slit, and a varied line-space planar reflection grating. Both the Wolter-I mirror and paraboloid pair are being fabricated at the NASA Marshall Space Flight Center (MSFC), using nickel replication. The MaGIXS mirror mandrels have been diamond turned, polished, and have yielded a set of engineering mirrors. Unlike other grazing incidence instruments, such as FOXSI, ART-XC, and IXPE, the MaGIXS prescriptions have large departure from a cone. This property exacerbates challenges with conventional lap polishing techniques and interferometric metrology. Here we discuss the progression of the optical surfaces of the mandrels through lap polishing, X-ray data from the replicated shells obtained in the MSFC Stray Light Facility (SLF), and our transition to using the ZEEKO computer numerical controlled (CNC) polisher for figure correction
Spectacular nucleosynthesis from early massive stars
Stars formed with initial mass over 50 Msun are very rare today, but they are
thought to be more common in the early universe. The fates of those early,
metal-poor, massive stars are highly uncertain. Most are expected to directly
collapse to black holes, while some may explode as a result of rotationally
powered engines or the pair-creation instability. We present the chemical
abundances of J0931+0038, a nearby low-mass star identified in early followup
of SDSS-V Milky Way Mapper, which preserves the signature of unusual
nucleosynthesis from a massive star in the early universe. J0931+0038 has
relatively high metallicity ([Fe/H] = -1.76 +/- 0.13) but an extreme odd-even
abundance pattern, with some of the lowest known abundance ratios of [N/Fe],
[Na/Fe], [K/Fe], [Sc/Fe], and [Ba/Fe]. The implication is that a majority of
its metals originated in a single extremely metal-poor nucleosynthetic source.
An extensive search through nucleosynthesis predictions finds a clear
preference for progenitors with initial mass > 50 Msun, making J0931+0038 one
of the first observational constraints on nucleosynthesis in this mass range.
However the full abundance pattern is not matched by any models in the
literature. J0931+0038 thus presents a challenge for the next generation of
nucleosynthesis models and motivates study of high-mass progenitor stars
impacted by convection, rotation, jets, and/or binary companions. Though rare,
more examples of unusual early nucleosynthesis in metal-poor stars should be
found in upcoming large spectroscopic surveys.Comment: 11 pages + 22 page appendix, accepted to ApJ
HER2-enriched subtype and novel molecular subgroups drive aromatase inhibitor resistance and an increased risk of relapse in early ER+/HER2+ breast cancer
BACKGROUND: Oestrogen receptor positive/ human epidermal growth factor receptor positive (ER+/HER2+) breast cancers (BCs) are less responsive to endocrine therapy than ER+/HER2- tumours. Mechanisms underpinning the differential behaviour of ER+HER2+ tumours are poorly characterised. Our aim was to identify biomarkers of response to 2 weeks’ presurgical AI treatment in ER+/HER2+ BCs. METHODS: All available ER+/HER2+ BC baseline tumours (n=342) in the POETIC trial were gene expression profiled using BC360™ (NanoString) covering intrinsic subtypes and 46 key biological signatures. Early response to AI was assessed by changes in Ki67 expression and residual Ki67 at 2 weeks (Ki672wk). Time-To-Recurrence (TTR) was estimated using Kaplan-Meier methods and Cox models adjusted for standard clinicopathological variables. New molecular subgroups (MS) were identified using consensus clustering. FINDINGS: HER2-enriched (HER2-E) subtype BCs (44.7% of the total) showed poorer Ki67 response and higher Ki672wk (p<0.0001) than non-HER2-E BCs. High expression of ERBB2 expression, homologous recombination deficiency (HRD) and TP53 mutational score were associated with poor response and immune-related signatures with High Ki672wk. Five new MS that were associated with differential response to AI were identified. HER2-E had significantly poorer TTR compared to Luminal BCs (HR 2.55, 95% CI 1.14–5.69; p=0.0222). The new MS were independent predictors of TTR, adding significant value beyond intrinsic subtypes. INTERPRETATION: Our results show HER2-E as a standardised biomarker associated with poor response to AI and worse outcome in ER+/HER2+. HRD, TP53 mutational score and immune-tumour tolerance are predictive biomarkers for poor response to AI. Lastly, novel MS identify additional non-HER2-E tumours not responding to AI with an increased risk of relapse
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