Detection of Chlamydia trachomatis mRNA using digital PCR as a more accurate marker of viable organism

© 2018, Springer-Verlag GmbH Germany, part of Springer Nature. Spontaneous resolution of urogenital Chlamydia trachomatis (CT) without treatment has previously been described, but a limitation of these reports is that DNA or RNA-based amplification tests used do not differentiate between viable infection and non-viable DNA. We modified a previously published CT mRNA detection (omp2) method to differentiate between viable infection and non-viable DNA in a sample of CT DNA PCR positive women. We modified a CT mRNA detection (omp2) method from reverse transcriptase qPCR (RTqPCR) to digital PCR (dPCR) and evaluated it in samples from CT DNA positive women. Firstly, CT infected McCoy B cells treated with azithromycin in vitro identified detectable mRNA levels disappeared <2 days, while DNA persisted up to 6 days. We used 55 self-collected vaginal swabs from a cohort of women diagnosed as DNA positive for chlamydia obtained pre- and 7 days of post-azithromycin treatment. Concordance with DNA results was higher for dPCR than RTqPCR (74.5% versus 65.5%). At visit 1, there was a strong linear relationship between DNA and mRNA (r = 0.9, p < 0.000); 24 samples had both mRNA and DNA detected (82.8%) and 5 had only DNA detected with a potential false positive proportion of 17.2% (95%CI: 5.8, 35.8). At visit 2, there was poor correlation between DNA and mRNA (r = 0.14, p = 0.55); eight specimens had only DNA detected (42.1%; 95%CI: 20.25, 66.50) and one had mRNA detected. DNA detection methods alone may detect non-viable DNA. Consideration should be given to further develop mRNA assays as ancillary tests to improve detection of viable chlamydia

Identifying and Characterizing Impact Melt Outcrops in the Nectaris Basin

The Nectaris Basin is an 820-km diameter, multi-ring impact basin located on the near side of the Moon. Nectaris is a defining stratigraphic horizon based on relationships between ejecta units, giving its name to the Nectarian epoch of lunar history. Lunar basin chronology based on higher resolution LRO imagery and topography, while assigning some important basins like Serenitatis to pre-Nectarian time, were generally consistent with those previously derived. Based on this stratigraphy, at least 11 large basins formed in the time between Nectaris and Imbrium. The absolute age of Nectaris, therefore, is a crucial marker in the lunar time-stratigraphic sequence for understanding the impact flux on the Moon, and by extension, the entire inner solar system. For several decades, workers have attempted to constrain the age of the Nectaris basin through radiometric dating of lunar samples. However, there is little agreement on which samples in our collection represent Nectaris, if any, and what the correct radiometric age of such samples is. The importance of the age of Nectaris goes far beyond assigning a stratigraphic marker to lunar chronology. Several dynamical models use Nectaris as their pin date, so that this date becomes crucial in understanding the time-correlated effects in the rest of the solar system. The importance of the Nectaris basin age, coupled with its nearside, mid-latitude location, make remnants of the impact-melt sheet an attractive target for a future mission, either for in-situ dating or for sample return. We have started exploring this possibility. We have begun a consortium data-analysis effort bringing multiple datasets and analysis methods to bear on these putative impact-melt deposits to characterize their extent, elemental composition and mineralogy, maturity and geologic setting, and to identify potential landing sites that meet both operational safety and science requirements

Managing contested spaces: Public managers, obscured mechanisms and the legacy of the past in Northern Ireland

Societies emerging from ethno-political and inter-communal conflict face a range of complex problems that stem directly from the recent lived experience of bloodshed and injury, militarisation, securitisation and segregation. As institutional agents in such an environment, public managers perform the dual role of both interpreting public policy and implementing it within a politically contested space and place. In this article we address how managers cope with the outworking of ethno-nationalist conflict and peace building within government processes and policy implementation and contend this is a subject of emerging concern within the wider public administration, urban studies and conflict literature. Using data from a witness seminar initiative on the Northern Ireland conflict transformation experience, we explain how public sector managers make sense of their role in post-agreement public management and highlight the importance of three identified mechanisms; ‘bricolage’, ‘diffusion’ and ‘translation’ in the management of public sector organisations and urban spaces in a context of entrenched conflict and an uncertain path to peace

The role of high frequency intra-daily data, daily range and implied volatility in multi-period Value-at-Risk forecasting

In this paper, we assess the informational content of daily range, realized variance, realized bipower variation, two time scale realized variance, realized range and implied volatility in daily, weekly, biweekly and monthly out-of-sample Value-at-Risk (VaR) predictions. We use the recently proposed Realized GARCH model combined with the skewed student distribution for the innovations process and a Monte Carlo simulation approach in order to produce the multi-period VaR estimates. The VaR forecasts are evaluated in terms of statistical and regulatory accuracy as well as capital efficiency. Our empirical findings, based on the S&P 500 stock index, indicate that almost all realized and implied volatility measures can produce statistically and regulatory precise VaR forecasts across forecasting horizons, with the implied volatility being especially accurate in monthly VaR forecasts. The daily range produces inferior forecasting results in terms of regulatory accuracy and Basel II compliance. However, robust realized volatility measures such as the adjusted realized range and the realized bipower variation, which are immune against microstructure noise bias and price jumps respectively, generate superior VaR estimates in terms of capital efficiency, as they minimize the opportunity cost of capital and the Basel II regulatory capital. Our results highlight the importance of robust high frequency intra-daily data based volatility estimators in a multi-step VaR forecasting context as they balance between statistical or regulatory accuracy and capital efficiency

Utilization of co-products from the biofuels industry as alternative protein sources in growing dairy heifer diets

Feeding co-products of the biofuels industry as alternative protein sources to growing dairy heifers can improve or maintain performance as well as reduce costs. Over the last five years we have conducted several studies evaluating the utilization of distillers grains and developing oilseed meals. All the studies were randomized complete block design experiments in which heifers were individually fed using Calan gates. Two 16-wk studies were conducted to evaluate the effects of limit-feeding dairy heifers distillers dried grains with solubles (DDGS) with varying forage to concentrate ratios. The first study had 48 heifers and treatments were 1) 30% DDGS, with diet fed at 2.65% of body weight (BW), 2) 40% DDGS, with the diet fed at 2.50% of BW, and 3) 50% DDGS, with the diet fed at 2.35% of BW. The remainder of the diets were grass hay and 1.5% mineral mix. The second study had 24 heifers and treatments were a corn and soybean product concentrate mix compared to DDGS. Both concentrate mixes were limit-fed at 0.8% of BW and grass hay was fed ad libitum. Results demonstrated that DDGS can be included at 30, 40 or 50% of dietary DM in replacement of hay in limit-fed diets or can be fed in replacement of corn and soybean meal with ad libitum grass hay and maintain growth performance. Gain to feed also increased as DDGS was increased in the diet. Research has also been conducted on camelina and carinata, which are promising sources of oil for biodiesel. The meals have high quality protein, but contain glucosinolates which can affect taste, growth, thyroid function, and limit dietary inclusion rates. A 12-wk study was conducted using 42 heifers with treatments including 10% of the diet as camelina meal, linseed meal, or DDGS. Feeding camelina meal maintained frame growth and average daily gain but decreased gain:feed compared to the other diets. Two 16-wk studies were also conducted on feeding carinata meal, one with 24 heifers and a second with 36 heifers. The first compared cold-pressed carinata meal with DDGS. The second compared solvent-extracted carinata meal with canola meal or a control diet containing soy products. Both studies demonstrated that carinata meal can be fed at 10% of the diet and maintain growth performance compared to commonly used protein sources. Overall, feeding alternative proteins can offer viable and economical options for growing dairy heifer diets

Structural Models Of The Liquidity Effect

In this paper we examine a number of recent studies that claim to have obtained a well-defined liquidity effect using structural VAR models based on broad measures of money. These studies can be distinguished in terms of the identifying restrictions, sample periods, and frequency of data used. We show that estimation of the structural coefficients of all these models can be achieved by instrumental-variable methods, where the instruments are predetermined variables and the estimated structural errors from other equations in the system. Overall, our judgment is that the evidence for a liquidity effect from these studies is much less certain than suggested in the original papers, primarily because of the poor quality of the instruments used in estimation and the sensitivity of the estimates to the sample period used. © 1998 by the President and Fellows of Harvard College and the Massachusetts Institute of Technology