1,789 research outputs found
Recommended from our members
Carbon reservoirs on Mars: Constraints from Martian meteorites
We have measured the abundance and stable isotopic composition of magmatic carbon extracted from a suite of shergottites. The results confirm previous findings that primordial carbon on Mars is isotopically lighter than that of the Earth
Quantifying the effect of aerial imagery resolution in automated hydromorphological river characterisation
Existing regulatory frameworks aiming to improve the quality of rivers place hydromorphology as a key factor in the assessment of hydrology, morphology and river continuity. The majority of available methods for hydromorphological characterisation rely on the identification of homogeneous areas (i.e., features) of flow, vegetation and substrate. For that purpose, aerial imagery is used to identify existing features through either visual observation or automated classification techniques. There is evidence to believe that the success in feature identification relies on the resolution of the imagery used. However, little effort has yet been made to quantify the uncertainty in feature identification associated with the resolution of the aerial imagery. This paper contributes to address this gap in knowledge by contrasting results in automated hydromorphological feature identification from unmanned aerial vehicles (UAV) aerial imagery captured at three resolutions (2.5 cm, 5 cm and 10 cm) along a 1.4 km river reach. The results show that resolution plays a key role in the accuracy and variety of features identified, with larger identification errors observed for riffles and side bars. This in turn has an impact on the ecological characterisation of the river reach. The research shows that UAV technology could be essential for unbiased hydromorphological assessment
Recommended from our members
Noble gases in Tagish Lake
From the introduction: Tagish Lake has been classified as a CI2 chondrite [1] with an interstellar grain abundance enhanced over that of CI1 and CM2 chondrites [2]. Noble gases have been used as markers for the presence of exotic, presolar grains in chondritic meteorites: Xe-HL (nanodiamonds) and Xe-s/Ne-E (SiC). We have measured 4He, Ne, Ar and Xe in whole-rock Tagish Lake, and an orthophosphoric acid-resistant residue, in an effort to define more precisely the relative abundances of the different presolar components present, and to verify whether or not the meteorite has an enhanced complement of presolar diamonds. For comparison, whole-rock samples of Orgueil and Murchison have also been analysed using the same experimental procedure
Recommended from our members
New data on carbon isotopic compositions of some ureilites
We have collected new C data from high resolution stepped combustion analyses of 5 ureilites to better constrain their relationships with O and mineralogical/petrographic groupings. This may help the future development of petrogenetic models
Recommended from our members
An integrated mineralogical, petrographic, light stable isotope and noble gas investigation of Sahara 99201 ureilite
New ureilite Sahara 99201 has been investigated to determine mineralogy, petrography, light stable isotopes and noble gases. The sample is a typical olivine pigeonite ureilite (Fo 78, Wo 10, En 72). C, N, O and Ar are consistent with other ureilites
Recommended from our members
Alteration of the Nakhlite Lava Pile: was water on the surface, seeping down, or at depth, percolating up? Evidence (such as it is) from carbonates
We present carbon and oxygen isotope data on carbonates in five nakhlites and use the results to interpret the martian weathering processes
Workplace Violence Prevention in the Emergency Department Utilizing the Broset Violence Checklist
Workplace violence (WPV) is an epidemic in healthcare and is particularly a problem in high-risk areas of the hospital, such as the Emergency Department (ED). Literature reviewed consisted of minimal information supporting a proactive tool to identify patients at risk for violence in the ED. The focus of this project was to implement the Broset Violence Checklist (BVC) in the ED to proactively identify patients at high risk for violence and allow staff to intervene before the patient escalates to the point of violence. The BVC was completed on every patient placed in a room in the ED over five months. The measured outcomes included Registered Nurse (RN) compliance with the tool, RN assaults, public safety officers (PSO) needing to lay hands on a patient versus standing by, and behavioral restraint usage. The results showed a 94.5% compliance rate with the tool, a decrease in RN assaults and PSOs laying hands on patients, and an increase in behavioral restraints.D.N.P
The light element geochemistry of Yamato-793605
Carbon, nitrogen, neon and argon abundances and isotopic compositions have been determined by stepped combustion-mass spectrometry on aliquots of the lherzolitic shergottite Yamato (Y)-793605. The meteorite has the lowest carbon abundance of any martian meteorite so far analysed. Once terrestrial contamination has been removed, Y79 contains only 7.3 ppm carbon with a δ^C∿-19‰. Carbon can be divided into four separate components, identified on the basis of combustion temperature and isotopic composition : (1) carbonates (possibly calcite; 1.2 ppm with δ^C∿-23‰); (2) magmatic carbon (1 ppm; δ^C∿-35±10‰); (3) martian atmospheric species and (4) cosmogenic carbon. The last three components can also be recognised in terms of their calculated nitrogen isotopic compositions. The isotopically-light carbonate in Y79 conforms to the observations made on other shergottites, that these meteorites have not been altered by surficial fluids in contact with the martian atmosphere, but rather contain carbonates produced from primary magmatic fluids. Neon and argon data were acquired simultaneously with nitrogen, but the small temperature increments selected for the analysis (to maximise information from the nitrogen experiment) resulted in low quantities of the noble gases being released, amounts close to that of the system blank. Only ^Ne yielded an abundance (2.2×10^cm^3 g^ STP) much higher than the blank, concentrations which, on the basis of their ^Ne/^Ne and ^Ne/^Ne ratios were found to be a 9 : 1 mix of cosmogenic neon with terrestrial atmospheric neon (from the blank). The approximate ^Ne exposure age of Y79 is ∿4 Myr, slightly higher than values for other lherzolitic shergottites
- …