Influence of the particle size distribution on the Critical State Properties of Mine Tailings

Arguably, critical state soil mechanics (CSSM) is now the preeminent methodology for understanding static liquefaction of mine tailings, having been used in the mining industry by the expert panels retained to investigate recent TSF failures. One of the key ingredients of the CSSM framework is the assessment of a critical state line, which separates contractive from dila-tive states. A critical state line is often defined by a linear relationship and two parameters, namely the altitude of the critical state line at 1 kPa (¿) and its slope (¿). In this study, we use the TAILENG mine tailings database to investigate potential relationships between the particle fea-tures and the particle size distribution and the critical state properties. Towards this end, the crit-ical state line is evaluated for a range of mine tailings with broad gradations and compressibility, defining ¿and ¿, with known particle size distributions. This information is subsequently used to investigate potential correlations. Insights from the observations are shared, and potential funda-mental mechanisms in explaining correlations between the critical state properties and particle features are discussed.Postprint (published version

Optical constants of a solar system organic analog and the Allende meteorite in the near and mid-infrared (1.5-13 {\mu}m)

Measurements of visible and near-infrared reflection (0.38-5 {\mu}m) and mid to far infrared emission (5-200 {\mu}m) from telescope and satellite remote sensing instruments make it possible to investigate the composition of planetary surfaces via electronic transitions and vibrational modes of chemical bonds. Red spectral slopes at visible and near infrared wavelengths and absorption features at 3.3 and 3.4 {\mu}m observed in circumstellar disks, the interstellar medium, and on the surfaces of solar-system bodies are interpreted to be due to the presence of organic material and other carbon compounds. Identifying the origin of these features requires measurements of the optical properties of a variety of relevant analog and planetary materials. Spectroscopic models of dust within circumstellar disks and the interstellar medium as well as planetary regoliths often incorporate just one such laboratory measurement despite the wide variation in absorption and extinction properties of organic and other carbon-bearing materials. Here we present laboratory measurements of transmission spectra in the 1.5-13 {\mu}m region and use these to derive real and imaginary indices of refraction for two samples: 1) an analog to meteoritic insoluble organic matter and 2) a powdered Allende meteorite sample. We also test our refractive index retrieval method on a previously published transmission spectrum of an Mg-rich olivine. We compare optical measurements of the insoluble organic-matter analog to those of other solar-system and extrasolar organic analogs, such as amorphous carbon and tholins, and find that the indices of refraction of the newly characterized material differ significantly from other carbonaceous samples.Comment: 16 pages, 12 figures, accepted for publication by PS

Molecular Brightness Approach for FRET Analysis of Donor-Linker-Acceptor Constructs at the Single Molecule Level: A Concept

In this report, we have developed a simple approach using single-detector fluorescence autocorrelation spectroscopy (FCS) to investigate the Förster resonance energy transfer (FRET) of genetically encoded, freely diffusing crTC2.1 (mTurquoise2.1-linker-mCitrine) at the single molecule level. We hypothesize that the molecular brightness of the freely diffusing donor (mTurquoise2.1) in the presence of the acceptor (mCitrine) is lower than that of the donor alone due to FRET. To test this hypothesis, the fluorescence fluctuation signal and number of molecules of freely diffusing construct were measured using FCS to calculate the molecular brightness of the donor, excited at 405 nm and detected at 475/50 nm, in the presence and absence of the acceptor. Our results indicate that the molecular brightness of cleaved crTC2.1 in a buffer is larger than that of the intact counterpart under 405-nm excitation. The energy transfer efficiency at the single molecule level is larger and more spread in values as compared with the ensemble-averaging time-resolved fluorescence measurements. In contrast, the molecular brightness of the intact crTC2.1, under 488 nm excitation of the acceptor (531/40 nm detection), is the same or slightly larger than that of the cleaved counterpart. These FCS-FRET measurements on freely diffusing donor-acceptor pairs are independent of the precise time constants associated with autocorrelation curves due to the presence of potential photophysical processes. Ultimately, when used in living cells, the proposed approach would only require a low expression level of these genetically encoded constructs, helping to limit potential interference with the cell machinery

Effect of Reduced versus Usual Lipid Emulsion Dosing on Bilirubin Neurotoxicity and Neurodevelopmental Impairment in Extremely Preterm Infants: Study Protocol for a Randomized Controlled Trial

BACKGROUND: Bilirubin neurotoxicity (BN) occurs in premature infants at lower total serum bilirubin levels than term infants and causes neurodevelopmental impairment. Usual dose lipid infusions in preterm infants may increase free fatty acids sufficiently to cause bilirubin displacement from albumin, increasing passage of unbound bilirubin (UB) into the brain leading to BN and neurodevelopmental impairment not reliably identifiable in infancy. These risks may be influenced by whether cycled or continuous phototherapy is used to control bilirubin levels. OBJECTIVE: To assess differences in wave V latency measured by brainstem auditory evoked responses (BAER) at 34-36 weeks gestational age in infants born ≤ 750 g or \u3c 27 weeks\u27 gestational age randomized to receive usual or reduced dose lipid emulsion (half of the usual dose) irrespective of whether cycled or continuous phototherapy is administered. METHODS: Pilot factorial randomized controlled trial (RCT) of lipid dosing (usual and reduced) with treatment groups balanced between cycled or continuous phototherapy assignment. Eligible infants are born at ≤ 750 g or \u3c 27 weeks\u27 gestational age enrolled in the NICHD Neonatal Research Network RCT of cycled or continuous phototherapy. Infants will randomize 1:1 to reduced or usual dose lipid assignment during the first 2 weeks after birth and stratified by phototherapy assignment. Free fatty acids and UB will be measured daily using a novel probe. BAER testing will be performed at 34-36 weeks postmenstrual age or prior to discharge. Blinded neurodevelopmental assessments will be performed at 22-26 months. Intention-to-treat analyses will be performed with generalized linear mixed models with lipid dose and phototherapy assignments as random effects covariates, and assessment for interactions. Bayesian analyses will be performed as a secondary analysis. DISCUSSION: Pragmatic trials are needed to evaluate whether lipid emulsion dosing modifies the effect of phototherapy on BN. This factorial design presents a unique opportunity to evaluate both therapies and their interaction. This study aims to address basic controversial questions about the relationships between lipid administration, free fatty acids, UB, and BN. Findings suggesting a reduced lipid dose can diminish the risk of BN would support the need for a large multicenter RCT of reduced versus usual lipid dosing

East Bay Coalition for the Homeless: Branding Study and Marketing Strategy

There are a number of potential positioning strategies. The two which make the most sense for the EBCH are to “position the EBCH away from others in the category” and to “position the EBCH as unique.” These strategies have the advantage of setting the EBCH apart from the other organizations that address homelessness. Occupying its own “position” in the minds of potential and current donors is not only an effective communications/marketing strategy but also a less costly one because it avoids head-to-head competition and comparisons

Predicting the impact of livestock grazing on birds using foraging height data

1. Habitat structure is a major determinant of bird species diversity. One process by which habitat structure is altered is livestock grazing, the most extensive land use across most continents. While the impacts of grazing on vegetation have received much attention, the effects on avifauna are less well known

The CpG Island Methylator Phenotype and Chromosomal Instability Are Inversely Correlated in Sporadic Colorectal Cancer

BACKGROUND & AIMS: The CpG island methylator phenotype (CIMP) is one of the mechanisms involved in colorectal carcinogenesis (CRC). Although CIMP is probably the cause of high-frequency microsatellite instability (MSI-H) sporadic CRCs, its role in microsatellite stable (MSS) tumors is debated. The majority of MSS CRCs demonstrate chromosomal instability (CIN) with frequent loss of heterozygosity (LOH) at key tumor suppressor genes. We hypothesized that the majority of sporadic CRCs without CIN would be associated with CIMP. METHODS: We tested 126 sporadic CRCs for MSI and LOH and categorized tumors into MSI, LOH, or MSI-/LOH- subgroups. Methylation status was evaluated using 6 CIMP-related markers (MINT1, MINT2, MINT31, p16(INK4alpha), p14(ARF), and hMLH1) and 6 tumor suppressor genes (PTEN, TIMP3, RUNX3, HIC1, APC, and RARbeta2). BRAF V600E mutation analysis was performed using allele-specific polymerase chain reaction and DNA sequencing. RESULTS: We observed frequent methylation at all 12 loci in all CRCs. BRAF V600E mutations correlated with the MSI (P < .0001) and MSI-/LOH- (P = .03) subgroups. MSI and MSI-/LOH- tumors exhibited more promoter methylation than CRCs with LOH (P < .0001). We also found an inverse correlation between the frequencies of methylation and LOH (rho = -0.36; P < .0001). CONCLUSIONS: The associations between methylation frequencies at CIMP-related markers and MSI or MSI-/LOH- sporadic CRCs suggest that the majority of these tumors evolve through CIMP. These findings suggest that CIN and CIMP represent 2 independent and inversely related mechanisms of genetic and epigenetic instability in sporadic CRCs and confirm that MSI cancers arise as a consequence of CIMP

Strontium and barium iodide high light yield scintillators

Europium-doped strontium and barium iodide are found to be readily growable by the Bridgman method and to produce high scintillation light yields

Monoceros OB4:a new association in Gaia DR2

We use Gaia DR2 data to survey the classic Monoceros OB1 region and look for the existence of a dispersed young population, co-moving with the cloud complex. An analysis of the distribution of proper motions reveals a 20-30 Myr association of young stars, about 300-400 pc away from the far side of the Mon OB1 complex, along the same general line-of-sight. We characterize the new association, Monoceros OB4, and estimate it contains between 1400 and 2500 stars, assuming a standard IMF, putting it on par in size with NGC\,2264. We find from the internal proper motions that Mon OB4 is unbound and expanding. Our results seem to unveil a larger and more complex Monoceros star formation region, suggesting an elongated arrangement that seems to be at least 300 x 60 pc.Comment: Accepted for publication in MNRAS Letters; 5 pages, 3 figure