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2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Kerry Emanuel

AbstractHistorical records of Atlantic hurricane activity, extending back to 1851, show increasing activity over time, but much or all of this trend has been attributed to lack of observations in the early portion of the record. Here we use a tropical cyclone downscaling model driven by three global climate analyses that are based mostly on sea surface temperature and surface pressure data. The results support earlier statistically-based inferences that storms were undercounted in the 19th century, but in contrast to earlier work, show increasing tropical cyclone activity through the period, interrupted by a prominent hurricane drought in the 1970s and 80 s that we attribute to anthropogenic aerosols. In agreement with earlier work, we show that most of the variability of North Atlantic tropical cyclone activity over the last century was directly related to regional rather than global climate change. Most metrics of tropical cyclones downscaled over all the tropics show weak and/or insignificant trends over the last century, illustrating the special nature of North Atlantic tropical cyclone climatology.


PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0248255
Author(s):  
Aleš Tichopád ◽  
Ladislav Pecen ◽  
Vratislav Sedlák

The pandemic caused by the SARS-CoV-2 virus is believed to originate in China from where it spread to other parts of the world. The first cluster of diseased individuals was reported in China as early as in December 2019. It has also been well established that the virus stroke Italy later in January or in February 2020, hence distinctly after the outbreak in China. The work by Apolone et al. published in the Italian Medical Journal in November 2020 and retracted upon expression of concern on 22 March 2021, however propose that the virus could have stroke people already in September 2019, possibly following even earlier outbreak in China. By fitting an early part of the epidemic curve with the exponential and extrapolating it backwards, we could estimate the day-zero of the epidemic and calculated its confidence intervals in Italy and China. We also calculated how probable it is that Italy encountered the virus prior 1 January 2020. We determined an early portion of the epidemic curve representing unhindered exponential growth which fit the exponential model with high determination >0.97 in both countries. We conservatively suggest that the day-zero in China and Italy was 8 December 2019 (95% CI: 3 Dec., 20 Dec.) and 22 January 2020 (95% CI: 16 Jan., 29 Jan.), respectively. Given the uncertainty of the very early data in China and adjusting hence our model to fit the exponentially behaved data only, we can even admit that the pandemic originated through November 2019 (95% CI: 31 Oct., 22 Dec.). With high confidence (p <0.01) China encountered the virus prior Italy. We generally view any pre-pandemic presence of the virus in humans before November 2019 as very unlikely. The later established dynamics of the epidemics data suggests that the country of the origin was China.


Author(s):  
Robin Karlin ◽  
Chris Naber ◽  
Benjamin Parrell

Purpose Real-time altered feedback has demonstrated a key role for auditory feedback in both online feedback control and in updating feedforward control for future utterances. The aim of this study was to examine adaptation in response to temporal perturbation using real-time perturbation of ongoing speech. Method Twenty native English speakers with no reported history of speech or hearing disorders participated in this study. The study consisted of four word blocks, using the phrases “a capper,” “a gapper,” “a sapper,” and “a zapper” (due to issues with the implementation of perturbation, “gapper” was excluded from analysis). In each block, participants completed a baseline phase (30 trials of veridical feedback), a ramp phase (feedback perturbation increasing to maximum over 30 trials), a hold phase (60 trials with perturbation held at maximum), and a washout phase (30 trials, feedback abruptly returned to veridical feedback). Word-initial consonant targets (voice onset time for /k, g/ and fricative duration for /s, z/) were lengthened, and the following stressed vowel (/æ/) was shortened. Results Overall, speakers did not adapt the production of their consonants but did lengthen their vowel production in response to shortening. Vowel lengthening showed continued aftereffects during the early portion of the washout phase. Although speakers did not adapt absolute consonant durations, consonant duration was reduced as a proportion of the total syllable duration. This is consistent with previous research that suggests that speakers attend to proportional durations rather than absolute durations. Conclusion These results indicate that speakers actively monitor proportional durations and update the temporal dynamics of planning units extending beyond a single segment.


2021 ◽  
Author(s):  
Aleš Tichopád ◽  
Ladislav Pecen

AbstractThe pandemic of the COVID-19 disease caused by the SARS-CoV-2 virus has been believed to originate in China and spread later to other parts of the world. It is well acknowledged that the first diseased individuals appeared in China as early as in December 2019, and possibly even earlier in November. It has also been well established that the virus stroke Italy later in January or in February 2020, distinctly after the outbreak in China. Paper by Apolone et al. published in a local Italian medical journal in November 2020 however exposed this chronology to doubt.By fitting early part of the epidemic curve with the exponential model and extrapolating it backwards in time, we could estimate the day-zero of the epidemic and calculated its confidence intervals in Italy and China. We also calculated how probable it is that Italy encountered the virus prior 1 January 2020.We determined an early portion of the epidemic curve representing unhindered exponential growth which fit the exponential model with high determination >0.97 in both countries. We suggest that the day-zero in China and Italy was 8 December (95% CI: 3 Dec., 20 Dec.) and 22 January (95% CI: 16 Jan., 29 Jan.), respectively. We could with high confidence reject that Italy encountered the virus earlier than China (p <0.01).Based on our analysis we oppose the findings published by Apolone at al. and view the proposed pre-pandemic presence of the virus in Italy as very unlikely.


2021 ◽  
Vol 64 (3) ◽  
pp. 1049-1062
Author(s):  
Jennifer L. Spencer ◽  
Vern Osborne ◽  
Bill Van Heyst

HighlightsAn adapted annular denuder system (ADS) was implemented in a broiler facility to measure secondary aerosols.Results show that secondary aerosols were not always associated with ammonium or ammonia.Chloride aerosols were significant in comparison to other species and were present at consistent concentrations.This study concludes that the chloride source was the feed in the feeding pans.Abstract. Fine particulate matter (PM2.5) is present in animal housing facilities from both primary and secondary sources. Measuring secondary aerosols in harsh environments with high gas and particulate concentrations, such as poultry housing facilities, is an ongoing challenge. This study presents the results from the implementation of an adapted annular denuder system (ADS) used to measure secondary PM2.5 from inside a broiler facility in Ontario, Canada. Results from this work show that secondary aerosols formed the majority of total PM2.5 during the early portion of the growth cycle. It was further determined that the ion balance between ammonium and anions was not consistent, leading to the conclusion that a significant portion of the aerosol species are associated with a previously unidentified source that is not necessarily due to secondary reactions. Keywords: Ammonia, Annular denuder system, Particulate matter, Poultry, Secondary aerosols.


Horticulturae ◽  
2020 ◽  
Vol 6 (4) ◽  
pp. 75
Author(s):  
Andrej Svyantek ◽  
Bülent Köse ◽  
John Stenger ◽  
Collin Auwarter ◽  
Harlene Hatterman-Valenti

Extreme winter temperatures during the 2018–2019 dormant season contributed to trunk collapse and complete trunk death of numerous genotypes throughout a diverse grapevine planting in eastern North Dakota, USA. Through the early portion of the dormant season, 12 genotypes were screened to identify lethal temperature exotherms of primary buds; from these results, none were anticipated to be fully prepared to survive the −37 °C minimum temperature recorded in the region. Trunk collapse, death, and survival were monitored for 35 replicated genotypes. New trunks were retrained from suckers and monitored for growth following trunk removal. Only five genotypes exceeded 50% trunk survival at the end of the 2019 growing season, ‘Valiant’, ‘King of the North’, ‘John Viola’, ‘Baltica’, and ‘Bluebell’. Following re-establishment, ‘La Crescent’ was the most vigorous genotype with the largest sucker circumference, sucker length, and internode length. Nearly all genotypes evaluated produced suckers with lengths approaching the high-wire trellis height (1.8 m), designating their potential for cordon retraining in 2020. Cumulatively, however, the lethal temperature exotherm results and the trunk survival examination indicate a harrowing need for investigation of new management practices (such as protected training systems) and the generation of new cold-hardy genotypes to enhance productivity under standard unprotected systems.


PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10101
Author(s):  
Sterling J. Nesbitt ◽  
John M. Zawiskie ◽  
Robert M. Dawley

Loricatan pseudosuchians (known as “rauisuchians”) typically consist of poorly understood fragmentary remains known worldwide from the Middle Triassic to the end of the Triassic Period. Renewed interest and the discovery of more complete specimens recently revolutionized our understanding of the relationships of archosaurs, the origin of Crocodylomorpha, and the paleobiology of these animals. However, there are still few loricatans known from the Middle to early portion of the Late Triassic and the forms that occur during this time are largely known from southern Pangea or Europe. Heptasuchus clarki was the first formally recognized North American “rauisuchian” and was collected from a poorly sampled and disparately fossiliferous sequence of Triassic strata in North America. Exposed along the trend of the Casper Arch flanking the southeastern Big Horn Mountains, the type locality of Heptasuchus clarki occurs within a sequence of red beds above the Alcova Limestone and Crow Mountain formations within the Chugwater Group. The age of the type locality is poorly constrained to the Middle—early Late Triassic and is likely similar to or just older than that of the Popo Agie Formation assemblage from the western portion of Wyoming. The holotype consists of associated cranial elements found in situ, and the referred specimens consist of crania and postcrania. Thus, about 30% of the osteology of the taxon is preserved. All of the pseudosuchian elements collected at the locality appear to belong to Heptasuchus clarki and the taxon is not a chimera as previously hypothesized. Heptasuchus clarki is distinct from all other archosaurs by the presence of large, posteriorly directed flanges on the parabasisphenoid and a distinct, orbit-overhanging postfrontal. Our phylogenetic hypothesis posits a sister-taxon relationship between Heptasuchus clarki and the Ladinian-aged Batrachotomus kupferzellensis from current-day Germany within Loricata. These two taxa share a number of apomorphies from across the skull and their phylogenetic position further supports ‘rauisuchian’ paraphyly. A minimum of three individuals of Heptasuchus are present at the type locality suggesting that a group of individuals died together, similar to other aggregations of loricatans (e.g., Heptasuchus, Batrachotomus, Decuriasuchus, Postosuchus).


2020 ◽  
Vol 642 ◽  
pp. A215
Author(s):  
Vasco M. J. Henriques ◽  
Chris J. Nelson ◽  
Luc H. M. Rouppe van der Voort ◽  
Mihalis Mathioudakis

Context. The chromosphere of the umbra of sunspots features an assortment of dynamic fine structures that are poorly understood and often studied separately. Small-scale umbral brightenings (SSUBs), umbral microjets, spikes or short dynamic fibrils (SDFs), and umbral dark fibrils are found in any observation of the chromosphere with sufficient spatial resolution performed at the correct umbral flash stage and passband. Understanding these features means understanding the dynamics of the umbral chromosphere. Aims. We aim to fully understand the dynamics of umbral chromosphere through analysis of the relationships between distinct observed fine features and to produce complete models that explain both spectral profiles and the temporal evolution of the features. We seek to relate such understanding to umbral flashes. Methods. We studied the spatial and spectral co-evolution of SDFs, SSUBs, and umbral flashes in Ca II 8542 Å spectral profiles. We produced models that generate the spectral profiles for all classes of features using non-local thermodynamic equilibrium radiative transfer with a recent version of the NICOLE inversion code. Results. We find that both bright SSUBs and dark SDF structures are described with a continuous feature in the parameter space that is distinct from the surroundings even in pixel-by-pixel inversions. We find a phase difference between such features and umbral flashes in both inverted line-of-sight velocities and timing of the brightenings. For umbral flashes themselves we resolve, for the first time in inversion-based semi-empirical modelling, the pre-flash downflows, post-flash upflows, and the counter-flows present during the umbral flash phase. We further present a simple time-dependent cartoon model that explains the dynamics and spectral profiles of both fine structure, dark and bright, and umbral flashes in umbral chromospheres. Conclusions. The similarity of the profiles between the brightenings and umbral flashes, the pattern of velocities obtained from the inversions, and the phase relationships between the structures all lead us to put forward that all dynamic umbral chromospheric structures observed to this date are a locally delayed or locally early portion of the oscillatory flow pattern that generates flashes, secondary to the steepening large-scale acoustic waves at its source. Essentially, SSUBs are part of the same shock or merely compression front responsible for the spatially larger umbral flash phenomenon, but out of phase with the broader oscillation.


2020 ◽  
Vol 33 (18) ◽  
pp. 7755-7775 ◽  
Author(s):  
Yue Dong ◽  
Kyle C. Armour ◽  
Mark D. Zelinka ◽  
Cristian Proistosescu ◽  
David S. Battisti ◽  
...  

AbstractRadiative feedbacks depend on the spatial patterns of sea surface temperature (SST) and thus can change over time as SST patterns evolve—the so-called pattern effect. This study investigates intermodel differences in the magnitude of the pattern effect and how these differences contribute to the spread in effective equilibrium climate sensitivity (ECS) within CMIP5 and CMIP6 models. Effective ECS in CMIP5 estimated from 150-yr-long abrupt4×CO2 simulations is on average 10% higher than that estimated from the early portion (first 50 years) of those simulations, which serves as an analog for historical warming; this difference is reduced to 7% on average in CMIP6. The (negative) net radiative feedback weakens over the course of the abrupt4×CO2 simulations in the vast majority of CMIP5 and CMIP6 models, but this weakening is less dramatic on average in CMIP6. For both ensembles, the total variance in the effective ECS is found to be dominated by the spread in radiative response on fast time scales, rather than the spread in feedback changes. Using Green’s functions derived from two AGCMs shows that the spread in feedbacks on fast time scales may be primarily due to differences in atmospheric model physics, whereas the spread in feedback evolution is primarily governed by differences in SST patterns. Intermodel spread in feedback evolution is well explained by differences in the relative warming in the west Pacific warm-pool regions for the CMIP5 models, but this relation fails to explain differences across the CMIP6 models, suggesting that a stronger sensitivity of extratropical clouds to surface warming may also contribute to feedback changes in CMIP6.


2020 ◽  
Vol 4 (2) ◽  
pp. 60-64
Author(s):  
Haidar Salim Anan

Leroyi n. gen., is introduced to include the Cretaceous-Neogene (predominantly Maastrichtian-Eocene) benthic Lagenid foraminiferids from many Tethyan localities that characterized by its slightly coiled early portion of the smooth test, later slightly arcuate uniserial chambers increasing in length as added, oblique depressed sutures, aperture radial of dorsal angle. I suggest Leroyi as a new genus to accommodate foraminifera with these characters. This new genus have been previously assigned to Marginulina sp. C of LeRoy (1953), and here assigned as a genotype of the new genus. Four species were previously described from two localities in Egypt (Maqfi section, Farafra Oasis and Nekhl section, Sinai) are treated here as a new species of the new genus, and formally named as: Leroyi aegyptiaca Anan, n. sp., L. maqfiensis Anan, n. sp., L. deserti (Said & Kenawy, 1956), L. ghorabi (Said & Kenawy, 1956). One Tunisian species: Leroyi tunisiana Anan, n. sp. is added to these Egyptian species. Another European and American species: Leroyi glabra (d’Orbigny) is added to these Laginid group. These six species of the Lagenid new genus Leroyi are recorded in six localities in the Tethys (USA, France, Italy, Tunisia Egypt, UAE and India).


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