The Effects of Thermonuclear Reaction-Rate Variations on 26Al Production in Massive Stars: a Sensitivity Study

We investigate the effects of thermonuclear reaction rate variations on 26Al production in massive stars. The dominant production sites in such events were recently investigated by using stellar model calculations: explosive neon-carbon burning, convective shell carbon burning, and convective core hydrogen burning. Post-processing nucleosynthesis calculations are performed for each of these sites by adopting temperature-density-time profiles from recent stellar evolution models. For each profile, we individually multiplied the rates of all relevant reactions by factors of 10, 2, 0.5 and 0.1, and analyzed the resulting abundance changes of 26Al. Our simulations are based on a next-generation nuclear physics library, called STARLIB, which contains a recent evaluation of Monte Carlo reaction rates. Particular attention is paid to quantifying the rate uncertainties of those reactions that most sensitively influence 26Al production. For stellar modelers our results indicate to what degree predictions of 26Al nucleosynthesis depend on currently uncertain nuclear physics input, while for nuclear experimentalists our results represent a guide for future measurements. We tabulate the results of our reaction rate sensitivity study for each of the three distinct massive star sites referred to above. It is found that several current reaction rate uncertainties influence the production of 26Al. Particularly important reactions are 26Al(n,p)26Mg, 25Mg(alpha,n)28Si, 24Mg(n,gamma)25Mg and 23Na(alpha,p)26Mg. These reactions should be prime targets for future measurements. Overall, we estimate that the nuclear physics uncertainty of the 26Al yield predicted by the massive star models explored here amounts to about a factor of 3.Comment: 44 pages, 16 figure

Acadian and Alleghenian remagnetization of the Jim Pond Formation, central western Maine, northern Appalachians

Samples were collected from ten sites of the Late Cambrian-Early Ordovician Jim Pond Formation for paleomagnetic study. Stepwise thermal demagnetization reveals three separable components of magnetization. Component I is typically removed by 350[deg]C; it is subparallel to the present day field (354[deg]/ + 76[deg] vs. 342[deg]/ + 72[deg]) at the site location (45.3[deg]N, 289.4[deg]E) and is considered to be a recent partial overprint. Component II, without tilt-correction, is a south-southeasterly and shallow direction (mean: 165[deg]/0[deg], k = 31.4, a95 = 8.6[deg]) that is removed over an intermediate temperature range (350-600[deg]C). Component III, without tilt-correction, is a northeasterly and shallow, upward direction (mean: 10[deg]/-24[deg], k = 21.5, a95 = 7.3[deg]) and is removed over the highest temperature range (480[deg] to 690[deg]C). Though not statistically significant, for Components II and III the precision parameter, k, decreases and the [alpha]95 increases when tilt-correction is applied, suggesting that both are post-folding magnetizations.Component II, without tilt correction, has a corresponding paleomagnetic pole located at 43[deg]N, 130[deg]E (dp, dm = 4.3[deg], 8.6[deg]), which falls near the Late Carboniferous segment of the Laurentian Apparent Polar Wander Path (APWP). Component III, without tilt correction, has a corresponding pole located at 32[deg]N, 98[deg]E (dp, dm = 4.7[deg], 7.8[deg]), which falls near the Lower-Middle Devonian segment of the APWP. We conclude that the Jim Pond Formation has undergone two Paleozoic remagnetization events, one in the Early to Middle Devonian and a second one in the Late Paleozoic. The ages of these remagnetizations coincide with the timing of major orogenic activity in the area i.e. the Acadian and Alleghenian, respectively. The remagnetization event associated with the Acadian pulse can be recognized in other paleomagnetic investigations in the northern Appalachians.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29457/1/0000539.pd

Incorporation of a high potential quinone reveals that electron transfer in Photosystem I becomes highly asymmetric at low temperature

Photosystem I (PS I) has two nearly identical branches of electron-transfer co-factors. Based on point mutation studies, there is general agreement that both branches are active at ambient temperature but that the majority of electron-transfer events occur in the A-branch. At low temperature, reversible electron transfer between P700 and A1A occurs in the A-branch. However, it has been postulated that irreversible electron transfer from P700 through A1B to the terminal iron-sulfur clusters FA and FB occurs via the B-branch. Thus, to study the directionality of electron transfer at low temperature, electron transfer to the iron-sulfur clusters must be blocked. Because the geometries of the donor–acceptor radical pairs formed by electron transfer in the A- and B-branch differ, they have different spin-polarized EPR spectra and echo- modulation decay curves. Hence, time-resolved, multiple-frequency EPR spectroscopy, both in the direct-detection and pulse mode, can be used to probe the use of the two branches if electron transfer to the iron-sulfur clusters is blocked. Here, we use the PS I variant from the menB deletion mutant strain of Synechocyctis sp. PCC 6803, which is unable to synthesize phylloquinone, to incorporate 2,3-dichloro-1,4-naphthoquinone (Cl2NQ) into the A1A and A1B binding sites. The reduction midpoint potential of Cl2NQ is approximately 400 mV more positive than that of phylloquinone and is unable to transfer electrons to the iron-sulfur clusters. In contrast to previous studies, in which the iron-sulfur clusters were chemically reduced and/or point mutations were used to prevent electron transfer past the quinones, we find no evidence for radical-pair formation in the B-branch. The implications of this result for the directionality of electron transfer in PS I are discussed

Edible Plant Database

The Edible Plant Database (EPD) is an outcome of the GROW Observatory, a European Citizen Science project on growing food, soil moisture sensing and land monitoring. This dataset was disseminated via a web service hosted by IIASA (Austria) that provides information about suitable plants for locations within Europe, based on climate. The web service was used in the GROW app, this dataset is the base information used for that service. Key growing data, for example, planting and harvesting calendars, suitability of location for growing are either typically dispersed across a plethora of sources or generic and only applicable at large scales. The latter is a significant constraint to the new grower who may be unaware of the impact of local micro-climate on growing. The EPD provides collates key data for one resource, the GROW app, that enables users across Europe to choose what to plant in their location at the time of query. It is a database populated with 15 growing parameters with a supporting database on germination of 146 edible plant species included in EPD. Planting calendars and germination data to all 12 European climate zones are also included with high resolution images purchased under licence. The EPD brings together planting, harvesting and growing requirements for a suite of crops that can be grown in Europe and uses these data to provide locally relevant advice for growers. The Edible Plant Database provides data based on geographical location and growing season to answer questions such as “What can I plant now” and “what can I plant that will yield a crop on some future date”. Further information on GROW Observatory can be found at www.growobservatory.org This data is made available under a CC-BY 4.0 licence https://creativecommons.org/licenses/by/4.0/ This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 690199 Keywords: Growing calendars, edible plants, local differences, climate zone, planting, harvestin

Reading the Bible in the 21st century: Some hermeneutical principles: Part 1

Many books and articles have been published over several decades on ‘biblical hermeneutics’ to capture the epistemology of biblical hermeneutics and the phenomenology of interpretation, communication and language in order to direct the Bible reader how to read the ancient texts, assembled in the Bible, sensibly. The first part of this essay looks briefly into the history of biblical hermeneutics of the past century in order to generate an orientation of how ‘biblical hermeneutics’ was regarded and applied as well as to constitute an environment for the investigation to follow in the rest of this essay and in a succeeding essay. In the second part of this essay, a few hermeneutical approaches are analysed in order to recommend a way forward for the dynamic analysis and interpretation (ἑρμηνεία) of biblical texts. This prepares the stage for the recommendation of two extra textures or aspects to be incorporated in the hermeneutical process, to be investigated in a succeeding essay.Christian Spirituality, Church History and Missiolog

Characterization of chlorophyll f synthase heterologously produced in Synechococcus sp. PCC 7002.

In diverse terrestrial cyanobacteria, Far-Red Light Photoacclimation (FaRLiP) promotes extensive remodeling of the photosynthetic apparatus, including photosystems (PS)I and PSII and the cores of phycobilisomes, and is accompanied by the concomitant biosynthesis of chlorophyll (Chl) d and Chl f. Chl f synthase, encoded by chlF, is a highly divergent paralog of psbA; heterologous expression of chlF from Chlorogloeopsis fritscii PCC 9212 led to the light-dependent production of Chl f in Synechococcus sp. PCC 7002 (Ho et al., Science 353, aaf9178 (2016)). In the studies reported here, expression of the chlF gene from Fischerella thermalis PCC 7521 in the heterologous system led to enhanced synthesis of Chl f. N-terminally [His]10-tagged ChlF7521 was purified and identified by immunoblotting and tryptic-peptide mass fingerprinting. As predicted from its sequence similarity to PsbA, ChlF bound Chl a and pheophytin a at a ratio of ~ 3-4:1, bound β-carotene and zeaxanthin, and was inhibited in vivo by 3-(3,4-dichlorophenyl)-1,1-dimethylurea. Cross-linking studies and the absence of copurifying proteins indicated that ChlF forms homodimers. Flash photolysis of ChlF produced a Chl a triplet that decayed with a lifetime (1/e) of ~ 817 µs and that could be attributed to intersystem crossing by EPR spectroscopy at 90 K. When the chlF7521 gene was expressed in a strain in which the psbD1 and psbD2 genes had been deleted, significantly more Chl f was produced, and Chl f levels could be further enhanced by specific growth-light conditions. Chl f synthesized in Synechococcus sp. PCC 7002 was inserted into trimeric PSI complexes

Delirium prediction in the intensive care unit: comparison of two delirium prediction models

Background: Accurate prediction of delirium in the intensive care unit (ICU) may facilitate efficient use of early preventive strategies and stratification of ICU patients by delirium risk in clinical research, but the optimal delirium prediction model to use is unclear. We compared the predictive performance and user convenience of the prediction model for delirium (PRE-DELIRIC) and early prediction model for delirium (E-PRE-DELIRIC) in ICU patients and determined the value of a two-stage calculation. Methods: This 7-country, 11-hospital, prospective cohort study evaluated consecutive adults admitted to the ICU who could be reliably assessed for delirium using the Confusion Assessment Method-ICU or the Intensive Care Delirium Screening Checklist. The predictive performance of the models was measured using the area under the receiver operating characteristic curve. Calibration was assessed graphically. A physician questionnaire evaluated user convenience. For the two-stage calculation we used E-PRE-DELIRIC immediately after ICU admission and updated the prediction using PRE-DELIRIC after 24 h. Results: In total 2178 patients were included. The area under the receiver operating characteristic curve was significantly greater for PRE-DELIRIC (0.74 (95% confidence interval 0.71-0.76)) compared to E-PRE-DELIRIC (0.68 (95% confidence interval 0.66-0.71)) (z score of -2.73 (p < 0.01)). Both models were well-calibrated. The sensitivity improved when using the two-stage calculation in low-risk patients. Compared to PRE-DELIRIC, ICU physicians (n = 68) rated the E-PRE-DELIRIC model more feasible. Conclusions: While both ICU delirium prediction models have moderate-to-good performance, the PRE-DELIRIC model predicts delirium better. However, ICU physicians rated the user convenience of E-PRE-DELIRIC superior to PRE-DELIRIC. In low-risk patients the delirium prediction further improves after an update with the PRE-DELIRIC model after 24 h

External validation of the UK Prospective Diabetes Study (UKPDS) risk engine in patients with type 2 diabetes

Treatment guidelines recommend the UK Prospective Diabetes Study (UKPDS) risk engine for predicting cardiovascular risk in patients with type 2 diabetes, although validation studies showed moderate performance. The methods used in these validation studies were diverse, however, and sometimes insufficient. Hence, we assessed the discrimination and calibration of the UKPDS risk engine to predict 4, 5, 6 and 8 year cardiovascular risk in patients with type 2 diabetes. The cohort included 1,622 patients with type 2 diabetes. During a mean follow-up of 8 years, patients were followed for incidence of CHD and cardiovascular disease (CVD). Discrimination and calibration were assessed for 4, 5, 6 and 8 year risk. Discrimination was examined using the c-statistic and calibration by visually inspecting calibration plots and calculating the Hosmer-Lemeshow χ(2) statistic. The UKPDS risk engine showed moderate to poor discrimination for both CHD and CVD (c-statistic of 0.66 for both 5 year CHD and CVD risks), and an overestimation of the risk (224% and 112%). The calibration of the UKPDS risk engine was slightly better for patients with type 2 diabetes who had been diagnosed with diabetes more than 10 years ago compared with patients diagnosed more recently, particularly for 4 and 5 year predicted CVD and CHD risks. Discrimination for these periods was still moderate to poor. We observed that the UKPDS risk engine overestimates CHD and CVD risk. The discriminative ability of this model is moderate, irrespective of various subgroup analyses. To enhance the prediction of CVD in patients with type 2 diabetes, this model should be update

Postapproval trials versus patient registries:comparability of advanced melanoma patients with brain metastases

Postapproval trials and patient registries have their pros and cons in the generation of postapproval data. No direct comparison between clinical outcomes of these data sources currently exists for advanced melanoma patients. We aimed to investigate whether a patient registry can complement or even replace postapproval trials. Postapproval single-arm clinical trial data from the Medicines Evaluation Board and real-world data from the Dutch Melanoma Treatment Registry were used. The study population consisted of advanced melanoma patients with brain metastases treated with targeted therapies (BRAF- or BRAF-MEK inhibitors) in the first line. A Cox hazard regression model and a propensity score matching (PSM) model were used to compare the two patient populations. Compared to patients treated in postapproval trials (n = 467), real-world patients (n = 602) had significantly higher age, higher ECOG performance status, more often ≥3 organ involvement and more symptomatic brain metastases. Lactate dehydrogenase levels were similar between both groups. The unadjusted median overall survival (mOS) in postapproval clinical trial patients was 8.7 (95% CI, 8.1-10.4) months compared to 7.2 (95% CI, 6.5-7.7) months (P < 0.01) in real-world patients. With the Cox hazard regression model, survival was adjusted for prognostic factors, which led to a statistically insignificant difference in mOS for trial and real-world patients of 8.7 (95% CI, 7.9-10.4) months compared to 7.3 (95% CI, 6.3-7.9) months, respectively. The PSM model resulted in 310 matched patients with similar survival (P = 0.9). Clinical outcomes of both data sources were similar. Registries could be a complementary data source to postapproval clinical trials to establish information on clinical outcomes in specific subpopulations

Dual pathway inhibition as compared to acetylsalicylic acid monotherapy in relation to endothelial function in peripheral artery disease, a phase IV clinical trial

Objective: Dual pathway inhibition (DPI) by combining acetylsalicylic acid (ASA) with low-dose rivaroxaban has been shown to reduce cardiovascular events in patients with peripheral arterial disease (PAD) when compared to ASA monotherapy. A potential explanation is that inhibition of factor Xa improves endothelial function through crosstalk between coagulation and inflammatory pathways, subsequently attenuating the occurrence of cardiovascular events. We hypothesize that the addition of rivaroxaban to ASA in PAD patients leads to improved endothelial function. Design: An investigator-initiated, multicentre trial investigating the effect of DPI on endothelial function. Methods: Patients, diagnosed with PAD, were enrolled in two cohorts: cohort A (Rutherford I-III) and cohort B (Rutherford IV-VI). Participants received ASA monotherapy for a 4-weeks run-in period, followed by 12 weeks of DPI. Macro- and microvascular endothelial dysfunction were studied by measuring carotid artery reactivity upon sympathetic stimulus and by measuring plasma endothelin-1 concentrations, respectively. All measurements were performed during the use of ASA (baseline) and after 12 weeks of DPI. Results: 159 PAD patients (111 cohort A, 48 cohort B) were enrolled. Twenty patients discontinued study drugs early. Carotid artery constriction upon sympathetic stimulation at baseline (ASA) and after 12 weeks of DPI was similar in the total group, 22.0 vs. 22.7% (p = 1.000), and in the subgroups (Cohort A 22.6 vs. 23.7%, p = 1.000; cohort B 20.5 vs. 20.5%, p = 1.000), respectively. The mean concentration of plasma endothelin-1 at baseline and after 12 weeks of DPI did not differ, 1.70 ± 0.5 vs. 1.66 ± 0.64 pmol/L (p = 0.440) in the total group, 1.69 ± 0.59 vs. 1.62 ± 0.55 pmol/L in cohort A (p = 0.202), and 1.73 ± 0.53 vs. 1.77 ± 0.82 pmol/L in cohort B (p = 0.682), respectively. Conclusion: Macro- and microvascular endothelial dysfunction, as reflected by carotid artery reactivity and plasma endothelin-1 concentrations, are not influenced in PAD patients by addition of low-dose rivaroxaban to ASA monotherapy for 12 weeks. Trial registration: https://clinicaltrials.gov/ct2/show/NCT04218656