541 research outputs found

    The Nineteenth Century Engagement Between Geological and Adventist Thought and its Bearing on the Twentieth Century Flood Geology Movement

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    The Seventh-day Adventist Church has from the early years of its existence reacted to the perceived challenge of geological thought to their nascent theology. In particular, the Sabbath of the fourth Commandment in Genesis 2 and the catastrophic global Flood described in Genesis 7 and 8 were targeted. The nineteenth century Adventist response has been one of shifting focus, changing strategies, and increasing intensity. Ellen White, the church’s co-founder and prophetess, was one of the first to sound a warning on theological implications of geology. Her perception of geology contained many pre-nineteenth century concepts disconnected from contemporary geological thinking. Long-time editor Uriah Smith used external documents, notably Presbyterian writings to guide the Adventist congregation with ways of responding to geological thought as it impacted on their faith. The first authentic Adventist evaluation of geology and its perceived link with evolution by Alonzo Jones took place in the mid-1880s. With his spirited response, Jones criticised geological stratigraphic concepts in order to neutralise the threat of burgeoning theistic evolutionary thought. His searching in the geological literature involved the use of contextomy. George McCready Price next ventured to nullify the established stratigraphic principles of geology in order to justify a single, global flood-based hypothesis to explain all fossiliferous sedimentary formations. To achieve this, he presented from established scientists selected citations out of their intended context. A special case is presented on Price’s questionable use of the reports of American field geologists McConnell and Willis on thrust faults in the Rocky Mountains. Price modified diagrams and failed to convey unmistakable evidence of a dynamic cause of complex stratigraphy to present his case for the global existence of reverse sequences of rock strata. He argued that since the geologists’ evidence for a fossil sequence of life in the rock stratigraphy is so greatly flawed, there must have been a single catastrophic event that better explained this. Adventist engagement with geological thought during this period saw a noticeable increase in the disregard of intellectual integrity. This study argues that intellectual dishonesty is not a valid way to support a preconceived interpretation of the scriptural narrative. History provides several examples where skewed accounts of events due to questionable intellectual sincerity have eventually been corrected. This research provides access points for interested persons to further investigate the historical aspects of the nineteenth century geology and Adventist thought engagement

    Directly tracing the vertical stratification of molecules in protoplanetary disks

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    We aim to directly trace the vertical location of the emitting surface of multiple molecular tracers in protoplanetary disks. Our sample of disks includes Elias 2-27, WaOph 6 and the sources targeted by the MAPS ALMA Large Program. The set of molecules studied include CO isotopologues in various transitions, HCN, CN, H2CO, HCO+, C2H and c-C3H2. The vertical emitting region is determined directly from the channel maps, implementing accurate masking of the channel emission to recover the vertical location of the emission surface even at large radial distances from the star and for low-SNR lines. The vertical location of the emitting layer is obtained for 4-10 lines in each disk. IM Lup, HD163296 and MWC 480 12CO and 13CO show vertical modulations, which are coincident with dust gaps and kinematical perturbations. We also present estimates of the gas pressure scale height in the disks from the MAPS sample. Compared to physical-chemical models we find good agreement with the vertical location of CO isotopologues. In HD 163296 CN and HCN trace a similar intermediate layer, for the other disks, the UV flux tracers and the vertical profiles of HCN and C2H are lower than predicted in theoretical models. HCN and H2CO show a highly structured vertical profile, possibly indicative of different formation pathways. It is possible to trace the vertical locations of multiple molecular species that trace a wide variety of physical and chemical disk properties. The distribution of CO isotopologues are found at a wide range of vertical heights z/r=z/r = 0.5-0.05. Other molecular lines are mostly found at z/rz/r \leq 0.15. The vertical layering of molecules is in agreement with theory in some systems, but not in all, therefore dedicated chemical-physical models are needed to further study and understand the emission surfaces.Comment: Accepted for publication in A&A. 29 pages, 28 figure

    Comparing different methods to retrieve cloud top height from Meteosat satellite data

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    Cloud parameters such as the Cloud Top Height (CTH), Cloud Top Temperature (CTT), emissivity, particle size and optical depth have always been matter of interest for the atmospheric community. Particularly the CTH provides information leading to better understand the cloud radiative effects. Although there are many meteorological satellites providing the CTH, there are other sensors, not devoted to this purpose, that give some information from which this crucial parameter can be estimated. In this contribution we will describe three different methodologies to retrieve the CTH. The first technique is based on stereo-vision algorithms and requires two different views of the same scene and does not need of extra atmospheric information. In the second one, brightness temperatures in two IR spectral bands are converted to real cloud temperature by means of the proposed algorithms. From the CTT, the CTH is estimated using temperature vertical profiles (measured or modeled). The third technique retrieves the CTH from the output parameters of post event simulations performed by a Numerical Weather Prediction (NWP) model that in this work will be the mesoscale model WRF (Weather Research Forecast). This article presents a preliminary work, in which the heights retrieved by the three methodologies applied to the geostationary satellite Meteosat 10 are compared with the heights given by MODIS sensor installed on the polar satellite AQUA. This promising results show that valuable information about CTH can be retrieved from Meteosat which provide high frequency and large scale data useful for weather and climate research

    Additive QTLs on three chromosomes control flowering time in woodland strawberry (Fragaria vesca L.)

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    Flowering time is an important trait that affects survival, reproduction and yield in both wild and cultivated plants. Therefore, many studies have focused on the identification of flowering time quantitative trait locus (QTLs) in different crops, and molecular control of this trait has been extensively investigated in model species. Here we report the mapping of QTLs for flowering time and vegetative traits in a large woodland strawberry mapping population that was phenotyped both under field conditions and in a greenhouse after flower induction in the field. The greenhouse experiment revealed additive QTLs in three linkage groups (LG), two on both LG4 and LG7, and one on LG6 that explain about half of the flowering time variance in the population. Three of the QTLs were newly identified in this study, and one co-localized with the previously characterized FvTFL1 gene. An additional strong QTL corresponding to previously mapped PFRU was detected in both field and greenhouse experiments indicating that gene(s) in this locus can control the timing of flowering in different environments in addition to the duration of flowering and axillary bud differentiation to runners and branch crowns. Several putative flowering time genes were identified in these QTL regions that await functional validation. Our results indicate that a few major QTLs may control flowering time and axillary bud differentiation in strawberries. We suggest that the identification of causal genes in the diploid strawberry may enable fine tuning of flowering time and vegetative growth in the closely related octoploid cultivated strawberry.Peer reviewe

    A major asymmetric ice trap in a planet-forming disk IV. Nitric oxide gas and a lack of CN tracing sublimating ices and a C/O ratio <1< 1

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    [Abridged] Most well-resolved disks observed with ALMA show signs of dust traps. These dust traps set the chemical composition of the planet forming material in these disks, as the dust grains with their icy mantles are trapped at specific radii and could deplete the gas and dust of volatiles at smaller radii. In this work we analyse the first detection of nitric oxide (NO) in a protoplanetary disk. We aim to constrain the nitrogen chemistry and the gas-phase C/O ratio in the highly asymmetric dust trap in the Oph-IRS 48 disk. We use ALMA observations of NO, CN, C2_2H, and related molecules and model the effect of the dust trap on the physical and chemical structure using the thermochemical code DALI. Furthermore, we explore how ice sublimation contributes to the observed emission lines. NO is only observed at the location of the dust trap but CN and C2_2H are not detected in the Oph-IRS 48 disk. This results in an CN/NO column density ratio of <0.05< 0.05 and thus a low C/O ratio at the location of the dust trap. The main gas-phase formation pathways to NO through OH and NH in the fiducial model predict NO emission that is an order of magnitude lower than is observed. The gaseous NO column density can be increased by factors ranging from 2.8 to 10 when the H2_2O and NH3_3 gas abundances are significantly boosted by ice sublimation. However, these models are inconsistent with the upper limits on the H2_2O and OH column densities derived from observations. We propose that the NO emission in the Oph-IRS 48 disk is closely related to the nitrogen containing ices sublimating in the dust trap. The non-detection of CN constrains the C/O ratio both inside and outside the dust trap to be <1< 1 if all nitrogen initially starts as N2_2 and 0.6\leq 0.6, consistent with the Solar value, if (part of) the nitrogen initially starts as N or NH3_3.Comment: Accepted for publication in Astronomy and Astrophysic

    Fire Affects Ecophysiology and Community Dynamics of Central Wisconsin Oak Forest Regeneration

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    In order to understand better the ecophysiological differences among competing species that might influence competitive interactions after, or in the absence of, fire, we examined the response to fire of four sympatric woody species found in intermediatesized gaps in a 30-yr-old mixed-oak forest in central Wisconsin. Selected blocks in the forest were burned in April 1987 by a low-intensity controlled surface fire. The fire had significant effects during the following growing season on community structure, foliar nutrient concentrations, and photosynthesis. Acer rubrum seedling density declined by 70% following the fire, while percent cover increased several-fold in Rubus allegheniensis. In general, leaf concentrations of N, P, and K were increased by the fire in all species, although the relative enhancement decreased as the growing season progressed. Daily maximum photosynthetic rates were 30-50% higher in burned than unburned sites for Prunus serotina, Quercus ellipsoidalis, and R. allegheniensis, but did not differ between treatments for A. rubrum. Mean sunlit photosynthetic rates and leaf conductances were stimulated by the burn for all species, with the greatest enhancement in photosynthesis measured in Q. ellipsoidalis. Leaf gas exchange in R. allegheniensis was most sensitive to declining leaf water potential and elevated vapor pressure gradient, with Q. ellipsoidalis the least sensitive. Fire had no discernable effect on water status of these plants during a year of relatively high rainfall. In comparison with other species, A. rubrum seedlings responded negatively after fire-both in terms of survival/reproduction (decline in the number of individuals) and relative leaf physiological performance. Fire enhanced the abundance of R. allegheniensis and the potential photosynthetic performance of R. allegheniensis, P. serotina, and particularly Q. ellipsoidalis. We conclude that post-fire stimulation of net photosynthesis and conductance was largely the result of enhanced leaf N concentrations in these species

    The diverse chemistry of protoplanetary disks as revealed by JWST

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    Early results from the JWST-MIRI guaranteed time programs on protostars (JOYS) and disks (MINDS) are presented. Thanks to the increased sensitivity, spectral and spatial resolution of the MIRI spectrometer, the chemical inventory of the planet-forming zones in disks can be investigated with unprecedented detail across stellar mass range and age. Here data are presented for five disks, four around low-mass stars and one around a very young high-mass star. The mid-infrared spectra show some similarities but also significant diversity: some sources are rich in CO2, others in H2O or C2H2. In one disk around a very low-mass star, booming C2H2 emission provides evidence for a ``soot'' line at which carbon grains are eroded and sublimated, leading to a rich hydrocarbon chemistry in which even di-acetylene (C4H2) and benzene (C6H6) are detected (Tabone et al. 2023). Together, the data point to an active inner disk gas-phase chemistry that is closely linked to the physical structure (temperature, snowlines, presence of cavities and dust traps) of the entire disk and which may result in varying CO2/H2O abundances and high C/O ratios >1 in some cases. Ultimately, this diversity in disk chemistry will also be reflected in the diversity of the chemical composition of exoplanets.Comment: 17 pages, 8 figures. Author's version of paper submitted to Faraday Discussions January 18 2023, Accepted March 16 202
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