scholarly journals Dynamics of dormancy regulation in ‘Sonata’ strawberry and its relation to flowering and runnering

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Anita Sønsteby ◽  
Ola M. Heide
Keyword(s):  
Dynamic Process ◽  
Freezing Temperature ◽  
Transient Growth ◽  
Complete Darkness ◽  
Dormant State ◽  
Growth Constraints ◽  
Higher Temperature ◽  
Potential Impact

Abstract Background Dormancy regulation in strawberry is a dynamic process that is causally interrelated with regulation of flowering. Interference between the two processes is therefore possible. Methods We studied dormancy control and its relation to flowering and runner formation in ‘Sonata’ strawberry under daylight phytotron conditions. Growth and flowering were observed in plants pretreated for 5 or 10 weeks at 10-h SD and 18-h LD at 6 and 18 ℃ and subsequently forced in a greenhouse in LD at 20 ℃ with and without previous chilling for 6 weeks at 2 ℃ in darkness. Results SD induced constrained leaf and inflorescence growth at both 6 and 18 ℃, while the typical strawberry semi-dormant condition was attained only by exposure to SD at 18 ℃ for 10 weeks, which also completely blocked runner formation. The constrained leaf and inflorescence growth observed in plants grown in SD at 18 ℃ were partially reversed by 6 weeks of chilling and gradually overcome in successively emerging leaves. While plants grown in LD at 18 ℃ for 10 weeks remained vegetative under subsequent forcing, they unexpectedly initiated flowers when subjected to chilling in darkness for 6 weeks before the forcing. Conclusions SD exposure at 18 ℃ constrained leaf and inflorescence growth in ‘Sonata’ strawberry, and when applied for 10 weeks, it induced the persistent semi-dormant state that is typical for strawberry. Transient growth constraints were also induced at 6 ℃ in both SD and LD, while the semi-dormant state was only attained by SD at the higher temperature. Flowering in complete darkness, which is known in both SD and LD plants, did also take place in ‘Sonata’ strawberry in response to chilling in the dark at 2 ℃ for 6 weeks. While the potential impact of the phenomenon seems limited for regulation of flowering in strawberry, we conclude that chilling in the dark at near-freezing temperature may substantially enhance flowering in marginally induced strawberry plants.

scholarly journals Impact of temperature and relative humidity on the transmission of COVID-19: a modelling study in China and the United States

BMJ Open ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. e043863
Author(s):  
Jingyuan Wang ◽  
Ke Tang ◽  
Kai Feng ◽  
Xin Lin ◽  
Weifeng Lv ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Relative Humidity ◽  
Human Mobility ◽  
The United States ◽  
Reproductive Number ◽  
Cross Sectional ◽  
The Usa ◽  
Higher Temperature ◽  
Potential Impact ◽  
The Impact

ObjectivesWe aim to assess the impact of temperature and relative humidity on the transmission of COVID-19 across communities after accounting for community-level factors such as demographics, socioeconomic status and human mobility status.DesignA retrospective cross-sectional regression analysis via the Fama-MacBeth procedure is adopted.SettingWe use the data for COVID-19 daily symptom-onset cases for 100 Chinese cities and COVID-19 daily confirmed cases for 1005 US counties.ParticipantsA total of 69 498 cases in China and 740 843 cases in the USA are used for calculating the effective reproductive numbers.Primary outcome measuresRegression analysis of the impact of temperature and relative humidity on the effective reproductive number (R value).ResultsStatistically significant negative correlations are found between temperature/relative humidity and the effective reproductive number (R value) in both China and the USA.ConclusionsHigher temperature and higher relative humidity potentially suppress the transmission of COVID-19. Specifically, an increase in temperature by 1°C is associated with a reduction in the R value of COVID-19 by 0.026 (95% CI (−0.0395 to −0.0125)) in China and by 0.020 (95% CI (−0.0311 to −0.0096)) in the USA; an increase in relative humidity by 1% is associated with a reduction in the R value by 0.0076 (95% CI (−0.0108 to −0.0045)) in China and by 0.0080 (95% CI (−0.0150 to −0.0010)) in the USA. Therefore, the potential impact of temperature/relative humidity on the effective reproductive number alone is not strong enough to stop the pandemic.

scholarly journals Abundance of Biological Ice Nucleating Particles in the Mississippi and Its Major Tributaries

Atmosphere ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 307 ◽  
Author(s):  
Bruce Moffett ◽  
Tom Hill ◽  
Paul DeMott
Keyword(s):  
Atmospheric Aerosols ◽  
River System ◽  
Freezing Temperature ◽  
The United States ◽  
Cloud Droplets ◽  
The North ◽  
Rivers And Lakes ◽  
Immersion Freezing ◽  
Major River ◽  
Potential Impact

Ice nucleating particles (INPs) are rare among atmospheric aerosols. However, through their ability to induce freezing of cloud droplets in cold clouds, they affect cloud lifetime, cloud albedo, and the efficiency and distribution of precipitation. While terrestrial sources of INPs are the focus of much research, the potential of rivers and lakes to be significant INP reservoirs has been neglected. In the first survey of a major river system, surface waters from the Mississippi, Missouri, Platte, and Sweetwater Rivers, all draining east and south from the Great Divide in the United States of America (USA), were tested for their INP concentrations. The survey comprised 49 samples, taken approximately every 150–250 km along 90% of the Mississippi (from Natchez, MS to the source at Bemidji, MN), the full length of the Missouri, 90% of the North Platte, and all of the Sweetwater. Samples were analysed using the immersion freezing method. The highest freezing temperature varied between −4 and −6 °C, and the concentration of INPs active at −10 °C or warmer ranged from 87 to 47,000 mL−1. The average INP concentration at −10 °C was 4950 mL−1, almost four orders of magnitude greater than the numbers of INPs typically found active at this temperature in seawater. The majority of INPs (69 to >99%) were heat labile (deactivated by heating to 95 °C) and therefore likely to be biological. Although the surface area of rivers is limited, their significant concentrations of INPs suggest that freshwater emissions should be investigated for their potential impact on regional cloud processes.

scholarly journals Pathogenicity of Pythium species to maize

2020 ◽  
Vol 158 (2) ◽  
pp. 335-347
Author(s):  
Christoph S. Schmidt ◽  
Andreas Leclerque ◽  
Tobias Pfeiffer ◽  
Johannes W. Goessling ◽  
Marc Orlik ◽  
...  
Keyword(s):  
Shoot Growth ◽  
Deciduous Trees ◽  
Maize Seedlings ◽  
Pea Seedlings ◽  
Bait Plants ◽  
Root And Shoot Growth ◽  
Dicotyledonous Plants ◽  
Higher Temperature ◽  
Maize Plants ◽  
Potential Impact

Abstract Pythium isolates from diseased and dead bait plants of maize and cress grown in compost or various soils (maize fields, parkland under deciduous trees, grassland) were characterised and tested for pathogenicity to maize (Zea mays L.). In pot tests performed under controlled conditions, pathogenicity of the isolates to maize was apparent by reduction of root and shoot growth, whereas damping-off of maize seedlings was less frequent. Contrarily, pea seedlings were killed by pathogenic Pythium isolates. Pythium isolates from diseased maize seedlings and pathogenic strains from other gramineous plants (P. phragmitis, P. aff.phragmitis, P. catenulatum) were not necessarily more virulent to maize compared to isolates originating from dicotyledonous plants (cress). The most virulent isolates originated from compost and caused a reduction of maize shoot growth of up to 60%. Phylogenetic analysis revealed that they were very closely related to P. ultimum var. ultimum and P. arrhenomanes, respectively. Isolates originating from maize fields, grassland and parkland under deciduous trees, a reference culture of P. arrhenomanes and strains of P. phragmitis, P. aff. phragmitis and P. catenulatum with known pathogenicity on reed were non-pathogenic on maize. Isolates from compost, and from maize fields generally had a higher temperature optimum for mycelial growth (30 °C) and a faster growth rate (1.5–2.0 mm h−1) compared to the isolates from parkland under deciduous trees and grassland soil (20–25 °C, ~1.0 mm h−1), respectively. This study indicates a potential impact of pathogenic Pythium on maize plants even in the absence of visible symptoms.

Alleviation of salinity and dark-enforced dormancy in Allenrolfea occidentalis seeds under various thermoperiods

2000 ◽  
Vol 48 (6) ◽  
pp. 745 ◽  
Author(s):  
Bilquees Gul ◽  
M. Ajmal Khan ◽  
Darrell J. Weber
Keyword(s):  
Growth Regulators ◽  
Temperature Regime ◽  
Critical Factor ◽  
Moderate Temperature ◽  
Germination Inhibition ◽  
Complete Darkness ◽  
Reversal Effect ◽  
Higher Temperature ◽  
Growth Promoting ◽  
Allenrolfea Occidentalis

The effect of germination-regulating chemicals on the alleviation of salinity-enforced germination inhibition of Allenrolfea occidentalis (S.Wats.) Kuntze at various thermoperiods in complete darkness was investigated. There was poor germination at cool temperatures and germination-regulating chemicals were ineffective in alleviating this effect. Germination in the dark increased progressively with increase in temperature and maximum germination was obtained at 25–35˚C thermoperiod. Ethephon and fusicoccin (FC) substantially reverted dark-induced inhibition at moderate thermoperiods. All other germination-regulating chemicals were more effective at moderate temperature, while germination was not specifically different from control at higher temperature. Salinity-enforced germination inhibition was partially alleviated by all growth regulators at the higher temperature regime (25–35˚C). Best reversal was obtained with the application of ethephon and FC. Our results suggest that temperature is the most critical factor influencing the germination of Allenrolfea seeds. Allenrolfea occidentalis seeds germinated better at higher than at lower temperatures in the dark and all of the growth-promoting compounds showed their maximum reversal effect at higher temperatures.

Dielectric abnormity of Sr4Nd2Ti4Nb6O30 tungsten bronze ceramics over a broad temperature range

2007 ◽  
Vol 22 (8) ◽  
pp. 2217-2222 ◽  
Author(s):  
X.L. Zhu ◽  
X.M. Chen ◽  
X.Q. Liu
Keyword(s):  
Tungsten Bronze ◽  
Freezing Temperature ◽  
Broad Temperature Range ◽  
Maximum Temperature ◽  
Relaxor Behavior ◽  
Temperature Range ◽  
Thermally Activated ◽  
Higher Temperature ◽  
Tan Δ ◽  
Lower Temperature

In the present paper, Sr4Nd2Ti4Nb6O30 ceramics with filled tungsten bronze structure were prepared, and the dielectric characteristics over a broad temperature range (123 to 623 K) were investigated. Two dielectric abnormities were observed in the entire frequency range (100 Hz to 1 MHz). One is at higher temperature corresponding to a diffuse ferroelectric transition (P4/mbm → P4bm), and the other at lower temperature shows relaxor characteristics in both ϵ′ and tan δ curves. An activation energy and freezing temperature of 0.1659 eV and 148.05 K, respectively, were obtained by analyzing the frequency dependence of the dielectric maximum temperature using the Vogel–Fulcher relationship. The relaxor behavior is attributed to a polar-glassy system with thermally activated polarization fluctuations above the freezing temperature. In addition, the dielectric constant was almost stable with both temperature and frequency in the temperature range of 300 to 430 K (between the two dielectric abnormities).

Nucleation of Disorder in Fe3Al Alloys

1967 ◽  
Vol 25 ◽  
pp. 312-313
Author(s):  
P. R. Swann ◽  
W. R. Duff ◽  
R. M. Fisher
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Annealing Temperature ◽  
Antiphase Domain ◽  
Effect Of Temperature ◽  
Domain Structures ◽  
Transmission Electron ◽  
Domain Boundaries ◽  
Higher Temperature ◽  
The One

Recently we have investigated the phase equilibria and antiphase domain structures of Fe-Al alloys containing from 18 to 50 at.% Al by transmission electron microscopy and Mössbauer techniques. This study has revealed that none of the published phase diagrams are correct, although the one proposed by Rimlinger agrees most closely with our results to be published separately. In this paper observations by transmission electron microscopy relating to the nucleation of disorder in Fe-24% Al will be described. Figure 1 shows the structure after heating this alloy to 776.6°C and quenching. The white areas are B2 micro-domains corresponding to regions of disorder which form at the annealing temperature and re-order during the quench. By examining specimens heated in a temperature gradient of 2°C/cm it is possible to determine the effect of temperature on the disordering reaction very precisely. It was found that disorder begins at existing antiphase domain boundaries but that at a slightly higher temperature (1°C) it also occurs by homogeneous nucleation within the domains. A small (∼ .01°C) further increase in temperature caused these micro-domains to completely fill the specimen.

Application Of Electron Probe Analyses Of Minerals In Discussing The Relationship Between Ductile Deformation And Metamorphism

1990 ◽  
Vol 48 (2) ◽  
pp. 250-251
Author(s):  
Fan Guochuan ◽  
Sun Zhongshi
Keyword(s):  
Chemical Composition ◽  
Shear Deformation ◽  
Electron Probe ◽  
General Rule ◽  
Granulite Facies ◽  
Ductile Deformation ◽  
Higher Temperature ◽  
Ductile Shear ◽  
The Relationship ◽  
Ductile Shear Deformation

Under influence of ductile shear deformation, granulite facies mineral paragenesis underwent metamorphism and changes in chemical composition. The present paper discusses some changes in chemical composition of garnet in hypers thene_absent felsic gnesiss and of hypersthene in rock in early and late granulite facies undergone increasing ductile shear deformation .In garnet fetsic geniss, band structures were formed because of partial melting and resulted in zoning from massive⟶transitional⟶melanocrate zones in increasing deformed sequence. The electron-probe analyses for garnet in these zones are listed in table 1 . The Table shows that Mno, Cao contents in garnet decrease swiftly from slightly to intensely deformed zones.In slightly and moderately deformed zones, Mgo contents keep unchanged and Feo is slightly lower. In intensely deformed zone, Mgo contents increase, indicating a higher temperature. This is in accord with the general rule that Mgo contents in garnet increase with rising temperature.

Effects of Gender, Parental Role, and Time on Infant- and Adult-Directed Read and Spontaneous Speech

2019 ◽  
Vol 62 (11) ◽  
pp. 4001-4014
Author(s):  
Melanie Weirich ◽  
Adrian Simpson
Keyword(s):  
Parental Involvement ◽  
Gender Identity ◽  
Spontaneous Speech ◽  
First Year ◽  
Space Size ◽  
Vowel Space ◽  
Potential Impact ◽  
Phonetic Features ◽  
And Gender ◽  
Description Task

Purpose The study sets out to investigate inter- and intraspeaker variation in German infant-directed speech (IDS) and considers the potential impact that the factors gender, parental involvement, and speech material (read vs. spontaneous speech) may have. In addition, we analyze data from 3 time points prior to and after the birth of the child to examine potential changes in the features of IDS and, particularly also, of adult-directed speech (ADS). Here, the gender identity of a speaker is considered as an additional factor. Method IDS and ADS data from 34 participants (15 mothers, 19 fathers) is gathered by means of a reading and a picture description task. For IDS, 2 recordings were made when the baby was approximately 6 and 9 months old, respectively. For ADS, an additional recording was made before the baby was born. Phonetic analyses comprise mean fundamental frequency (f0), variation in f0, the 1st 2 formants measured in /i: ɛ a u:/, and the vowel space size. Moreover, social and behavioral data were gathered regarding parental involvement and gender identity. Results German IDS is characterized by an increase in mean f0, a larger variation in f0, vowel- and formant-specific differences, and a larger acoustic vowel space. No effect of gender or parental involvement was found. Also, the phonetic features of IDS were found in both spontaneous and read speech. Regarding ADS, changes in vowel space size in some of the fathers and in mean f0 in mothers were found. Conclusion Phonetic features of German IDS are robust with respect to the factors gender, parental involvement, speech material (read vs. spontaneous speech), and time. Some phonetic features of ADS changed within the child's first year depending on gender and parental involvement/gender identity. Thus, further research on IDS needs to address also potential changes in ADS.

Exploring the Potential Impact of Sentence-Level Comprehension and Sentence-Level Fluency on Deaf Students' Passage Comprehension

2020 ◽  
Vol 63 (7) ◽  
pp. 2281-2292
Author(s):  
Ying Zhao ◽  
Xinchun Wu ◽  
Hongjun Chen ◽  
Peng Sun ◽  
Ruibo Xie ◽  
...  
Keyword(s):  
Independent Predictor ◽  
Vocabulary Knowledge ◽  
Group Differences ◽  
Regression Analyses ◽  
Deaf Students ◽  
Mediating Role ◽  
Sentence Level ◽  
Mediating Mechanisms ◽  
Potential Impact ◽  
The Relationship

Purpose This exploratory study aimed to investigate the potential impact of sentence-level comprehension and sentence-level fluency on passage comprehension of deaf students in elementary school. Method A total of 159 deaf students, 65 students ( M age = 13.46 years) in Grades 3 and 4 and 94 students ( M age = 14.95 years) in Grades 5 and 6, were assessed for nonverbal intelligence, vocabulary knowledge, sentence-level comprehension, sentence-level fluency, and passage comprehension. Group differences were examined using t tests, whereas the predictive and mediating mechanisms were examined using regression modeling. Results The regression analyses showed that the effect of sentence-level comprehension on passage comprehension was not significant, whereas sentence-level fluency was an independent predictor in Grades 3–4. Sentence-level comprehension and fluency contributed significant variance to passage comprehension in Grades 5–6. Sentence-level fluency fully mediated the influence of sentence-level comprehension on passage comprehension in Grades 3–4, playing a partial mediating role in Grades 5–6. Conclusions The relative contributions of sentence-level comprehension and fluency to deaf students' passage comprehension varied, and sentence-level fluency mediated the relationship between sentence-level comprehension and passage comprehension.

Red Flags: Barriers to Listening and Spoken Language in Children with Hearing Loss

2014 ◽  
Vol 24 (1) ◽  
pp. 11-18
Author(s):  
Andrea Bell ◽  
K. Todd Houston
Keyword(s):  
Hearing Loss ◽  
Early Diagnosis ◽  
Skill Acquisition ◽  
Dynamic Process ◽  
Spoken Language ◽  
Red Flags ◽  
Careful Monitoring ◽  
Auditory Development ◽  
Children With Hearing Loss ◽  
Family Centered

To ensure optimal auditory development for the acquisition of spoken language, children with hearing loss require early diagnosis, effective ongoing audiological management, well fit and maintained hearing technology, and appropriate family-centered early intervention. When these elements are in place, children with hearing loss can achieve developmental and communicative outcomes that are comparable to their hearing peers. However, for these outcomes to occur, clinicians—early interventionists, speech-language pathologists, and pediatric audiologists—must participate in a dynamic process that requires careful monitoring of countless variables that could impact the child's skill acquisition. This paper addresses some of these variables or “red flags,” which often are indicators of both minor and major issues that clinicians may encounter when delivering services to young children with hearing loss and their families.

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