Different Regimes Of Temperature Research Articles

Characterization of seed micro-morphometry and optimization of germination assay conditions of Bergenia ciliata - a highly valued medicinal plant

Bergenia ciliata, a valuable medicinal perennial herb, belongs to the family Saxifragaceae. It bears very minute seeds which exhibit poor viability, germination potential and storability. Thus, the present study aimed to analyze the seed characters and germination biology of this medicinal herb. The study revealed that seeds were irregular shaped and dark brown coloured with average length ∼0.93 mm and width ∼0.31 mm. Test weight of seeds ranged between 42.6 and 56.4 mg, and moisture content varied from 7.05 to 10.46%. To standardize the conditions required for germination, the experiment was conducted under different regimes of temperature either in the light or in the dark. Results revealed that mean germination time was shortest and germination percentage highest (94%) when seeds were incubated at 20 °C with light. Seed imbibition pattern was studied at 24 h intervals starting from day zero, and it was found that changes in seed dimensions were small during the first 24 h but were greatest between 24 and 48 h. The experiment also revealed that average length of 8-day old seedling was 4.71 mm whereas it was 5.92 mm with better proportion of root length in 10-day old seedlings.

Thermodynamics of massless particles in curved spacetime

This work is devoted to study the behavior of massless particles within the context of curved spacetime. In essence, we investigate the consequences of the scale factor [Formula: see text] of the Friedmann–Robertson–Walker metric in the Einstein–aether formalism to study photon-like particles. To do so, we consider the system within the canonical ensemble formalism in order to derive the following thermodynamic state quantities: spectral radiance, Helmholtz free energy, pressure, entropy, mean energy and the heat capacity. Moreover, the correction to the Stefan–Boltzmann law and the equation of states are also provided. Particularly, we separate our study within three distinct cases, i.e. [Formula: see text] [Formula: see text]; [Formula: see text] [Formula: see text]; [Formula: see text] [Formula: see text]. In the first one, the results are derived numerically. Nevertheless, for the rest of the cases, all the calculations are accomplished analytically showing explicitly the dependence of the scale factor [Formula: see text] and the Riemann zeta function [Formula: see text]. Furthermore, our analyses are accomplished in general taking into account three different regimes of temperature of the universe, i.e. the inflationary era ([Formula: see text][Formula: see text]GeV), the electroweak epoch ([Formula: see text][Formula: see text]GeV) and the cosmic microwave background ([Formula: see text][Formula: see text]GeV).

Bouncing universe in a heat bath

In this paper, we develop a thermal description for photon modes within the context of bouncing universe. Within this study, we start with a Lorentz-breaking dispersion relation which accounts for modified Friedmann equations with a bounce solution. We calculate the spectral radiance, the entropy, the Helmholtz free energy, the heat capacity and the mean energy. Nevertheless, the latter two ones turn out to contribute only in a trivial manner. Furthermore, one intriguing aspect gives rise to: for some configurations of [Formula: see text], [Formula: see text] and [Formula: see text], the thermodynamical behavior of the system seems to indicate instability. However, despite showing this particularity, the solutions of the thermodynamic functions in general turn out to agree with the literature, e.g. the second law of thermodynamics is maintained. More so, all the results are derived analytically and three different regimes of temperature of the universe are also considered, i.e. the inflationary era, the electroweak epoch and the cosmic microwave background.

Active control of jet breakup and droplet formation using temperature modulation

Different regimes of temperature modulated breakup were studied using a slender jet model. The instability is induced through capillary and Marangoni stresses and can be used to control droplet formation in terms of intact length and resultant drop size distribution, which is otherwise irregular due to the inevitable presence of background noise. When thermal modulation is weak, the surface tension gradient forces act only as a trigger and curvature-gradient forces soon take over and grow exponentially downstream of the jet due to inertio-capillary growth. When thermal modulation is strong, the surface tension gradient forces not only act as a trigger, but remain significant till breakup.

Climate and nomadic migration in a nonlinear world: evidence of the historical China

This paper deals with climate change and nomadic migration relationships at a long term and wide geographical scale using a statistical approach in the vein of Bai and Kung (2011). More precisely, it presents a reassessment of these relationships in a nonlinear world using threshold regressions, time varying-copula and nonlinear causality tests. The large amount of historical records in China enables us to re-interpret the link between climate and historical social dynamics (Hsiang et al., 2013) through different regimes of temperatures and precipitations.

Aging Process of Cadmium, Copper, and Lead under Different Temperatures and Water Contents in Two Typical Soils of China

Aging process of exogenous heavy metals in soil is significant for reducing their environmental risk due to the redistribution of species of soil heavy metals. A red soil (ultisol) and a brown soil (alfisol) were selected to investigate the aging process of cadmium (Cd), copper (Cu), and lead (Pb) under different regimes of temperature and water content. Most introduced heavy metals were all transformed from dissolved fraction to more stable fractions within 5 days of incubation. During incubation, most Pb existed in the fraction bound to Fe/Mn oxides, while exchangeable and carbonate-associated fraction was the dominant portion for Cd and Cu, suggesting that the transformation rate followed the order: Pb > Cu > Cd. The exchangeable and carbonate-associated fraction in red soil, which was characterized with higher pH and Fe/Al/Mn oxides and lower organic matter (OM), was significantly higher than that in brown soil, implying that soil OM was the important factor affecting the aging process of soil heavy metals in the present study. In addition, increases of temperature and soil water content can accelerate the transformation of most introduced Cd, Cu, and Pb to more stable forms in the soils. The results indicated that soil properties, environmental factors (i.e., temperature and water content), types of heavy metals, and pollution time can significantly affect the aging process of exogenous heavy metals.

Exogenous Silicon Modulates Growth, Physio-Chemicals and Antioxidants in Barley (Hordeum vulgare L.) Exposed to Different Temperature Regimes

The exogenous application of silicon (Si) is reported to enhance tolerance of plants against various environmental stresses. Therefore, the present study was carried out to examine the influence of foliar applied Si (1.5 mM) on growth, physiochemical processes and antioxidant defense system of barley plants (cvs. Jow-83 and B-12026) under different regimes of temperature (20 °C (control), 25 °C, 30 °C, and 35 °C). High temperature (HT) regimes caused a significant (P < 0.001) decline in shoot (68% and 84%) and root (44% and 77%) dry masses, leaf area (66% and 81%), chlorophyll (Chl) a (11% and 70%), Chl b (69% and 71%), carotenoids (60% and 62%), anthocyanins (56%), total soluble proteins (62%) and phenolics (36% and 50%) contents in both cvs. Jow-83 and B-12026, respectively. A significant (P < 0.001) increase in superoxide dismutase (205% and 133%), peroxidase (128% and 88%) and catalase (127% and 87%) activities was recorded in stressed plants of both cultivars, respectively. Moreover, HT stress markedly (P < 0.001) increased hydrogen peroxide (H2O2) (54% and 75%) and malondialdehyde (MDA) (52% and 149%) levels in both cultivars that activated the oxidative stress. But, plants treated with Si showed better growth and had higher total soluble proteins (18% and 12%), anthocyanins (74% and 39%), flavonoids (31% and 27%) and phenolics (39% and 19%) as well as the activities of SOD (43% and 29%), POD (46% and 40%) and CAT (24% and 63%) enzymes. Application of Si reduced HT-mediated oxidative stress by decreasing the concentration of MDA (39% and 49%) and H2O2 (14% and 56%) and increased shoot (49% and 46%) and root (40% and 34%) dry masses, Chl a (10% and 86%), Chl b (82% and 81%), and carotenoids (53% and 33%) in both barley cultivars. Plants of cv. Jow-83 showed more tolerance to temperature regimes than that of cv. B-12026 as evident from higher plant dry masses. Thus, our findings exhibited that foliar-applied Si is an efficient strategy that can be used to enhance the tolerance of barley plants to HT stress.

Correlation between Strawberry (Fragaria ananassa Duch.) Productivity and Photosynthesis-Related Parameters under Various Growth Conditions.

In the present study, we investigated changes in chlorophyll fluorescence, photosynthetic parameters and fruit yields, as well as fruit phytochemical accumulation of strawberry (Fragaria ananassa Duch.) that had been cultivated in a greenhouse under different combinations of light intensity and temperature. In plants grown with low light (LL) photosystem II chlorophyll fluorescence was found to increase as compared with those grown under high light (HL). When strawberry plants were grown with temperature higher than 5°C in addition to LL, they showed decrease in non-photochemical quenching (NPQ), photochemical quenching (qP), as well as chlorophyll fluorescence decrease ratio (RFd) when compared with other combinations of light and temperature. Moreover, fruit yield of strawberry was closely correlated with chlorophyll fluorescence-related parameters such as NPQ, qP, and RFd, but not with the maximum efficiency of PS II (Fv/Fm). Although plant groups grown under different combinations of light and temperature showed almost comparable levels of photosynthesis rates (Pr) when irradiated with low-intensity light, they displayed clear differences when measured with higher irradiances. Plants grown under HL with temperature above 10°C showed the highest Pr, in contrast to the plants grown under LL with temperature above 5°C. When the stomatal conductance and the transpiration rate were measured, plants of each treatment showed clear differences even when analyzed with lower irradiances. We also found that fruit production during winter season was more strongly influenced by growth temperature than light intensity. We suggest that fruit productivity of strawberry is closely associated with chlorophyll fluorescence and photosynthesis-related parameters during cultivation under different regimes of temperature and light.

Impact of Polymer Electrolyte Membrane Properties on Transport, Performance and Durability

The structure and properties of the polymer electrolyte membrane has a major impact on the MEA performance and durability. Polymers with different chemical structures can propose different mechanisms for water and proton transport which lead to differences in performance and durability. For membranes with similar chemical structures, factors such as thickness and equivalent weight (EW) are crucial in transport and therefore could cause differences in the performance. The focus of this work was a closer look at the impact of these properties, and their changes due to degradation, on the performance and durability of the MEA and its components. The impact of membrane thickness and equivalent weight was studied by comparing the water content of different PFSA membranes as a function of relative humidity (RH). The data was then used to further discuss the conductivity and hydrogen permeability of the membranes in different regimes of temperature and RH. The impact of membrane chemical degradation on transport property was studied by comparing the membrane conductivity, thickness, hydrogen permeability and performance before and after membrane degradation. To study the impact of membrane properties on cathode catalyst performance and degradation, the cathode degradation test was applied on MEAs with and without membrane degradation, and the results were compared. The water content (Lambda) of all membranes showed a type II isotherm increase by increasing the relative humidity. Lambda was found to be independent of membrane thickness and equivalent weight, while, as expected, the absolute water content (g water/g membrane) showed a decrease at higher equivalent weights. Increasing the relative humidity and operational temperature showed an increase in membrane conductivity. Higher thickness or higher equivalent weight both resulted in higher membrane resistance; supporting a more general trend which is the linear increase of membrane conductivity with increase in the absolute water content. Cathode degradation testing showed an impact on the ECSA loss and performance. The effect was more intense for thinner or lower EW membranes suggesting that membrane water content was the contributing factor. After the membrane degradation test, losses in membrane thickness, membrane conductivity, performance and ECSA were observed. In addition, the hydrogen crossover increased due to the membrane thinning. The membranes with pre-existing degradation showed less ECSA loss but increased performance losses. This trend was explained by the combination of higher catalyst layer ionomer resistance and platinum depletion which lead to higher catalyst layer ionic losses related to a reaction distribution shift further into the catalyst layer. Acknowledgements: Funding was provided by Department of Energy EERE Hydrogen and Fuel Cell Technology Program (Project DE-EE0006375).

Increase in Temperature Induces the Malathion Toxicity in Pangasianodon hypophthalmus: A Short Term Acute Test

The study was conducted to evaluate the effect of higher temperature beyond optimum range on acute toxicity for malathion (effective concentration 50 %) in Pangasianodon hypophthalmus. A 2 days renewal bioassay system for 96 h was used to determine LC50 value of malathion at three different regimes of temperature that is 30, 32 and 34 °C considering as T1, T2 and T3, respectively. The physico-chemical parameters of water of different treatment groups were estimated during pre and post-exposure of test chemical, following standard methods. The result of short term acute toxicity test at 96 h LC50 values through probit analysis was found to be 7.76, 6.45 and 4.46 µL L−1 for T1, T2, and T3, respectively. The 96 h LC50 of malathion at 34 °C was found to be significantly (p < 0.01) lower as compared with estimated LC50 for malathion at 30 and 32 °C. High temperature and free carbon dioxide coupled with low dissolved oxygen were significantly noticed in T3 group when compared to T1 and T2 groups. Lower LC50 of malathion at 34 °C as compared to 30 and 32 °C showed that at a higher temperature, the toxicity of malathion increased, signifying diminished fish protective response to malathion toxicity. The current study reflects the impact of increased temperature on pesticide toxicity in the aquatic ecosystem, alarming the aqua farmers to judiciously use malathion in ponds.

Probing Out-of-Plane Charge Transport in Black Phosphorus with Graphene-Contacted Vertical Field-Effect Transistors.

Black phosphorus (BP) has recently emerged as a promising narrow band gap layered semiconductor with optoelectronic properties that bridge the gap between semimetallic graphene and wide band gap transition metal dichalcogenides such as MoS2. To date, BP field-effect transistors have utilized a lateral geometry with in-plane transport dominating device characteristics. In contrast, we present here a vertical field-effect transistor geometry based on a graphene/BP van der Waals heterostructure. The resulting device characteristics include high on-state current densities (>1600 A/cm(2)) and current on/off ratios exceeding 800 at low temperature. Two distinct charge transport mechanisms are identified, which are dominant for different regimes of temperature and gate voltage. In particular, the Schottky barrier between graphene and BP determines charge transport at high temperatures and positive gate voltages, whereas tunneling dominates at low temperatures and negative gate voltages. These results elucidate out-of-plane electronic transport in BP and thus have implications for the design and operation of BP-based van der Waals heterostructures.

Characterization of volatile metabolites associated with confinement odour during the shelf-life of vacuum packed lamb meat under different storage conditions

Confinement odour was investigated. Volatiles were extracted directly from the pack, using solid phase microextraction and analysed by gas chromatography–mass spectrometry. Sensory evaluation and microbiological analysis of the meat surface were also performed. Commercial samples of vacuum packed lamb legs (n=85), from two meat processing plants, were kept for 7weeks at −1.5°C then at different regimes of temperature (−1.5 to +4°C) until 11, 12 or 13weeks. Persistent odour was observed in 66% of samples, confinement odour in 24% and no odour in 11%. Volatiles associated with confinement odour (3-methyl-butanal, 3-hydroxy-2-butanone and sulphur dioxide) corresponded with end/sub products of glucose fermentation and catabolism of amino acids by bacteria (all bacteria naturally found in meat and do not represent a risk to health). Confinement odour could indicate a stage at which the environment for bacteria growth is becoming favourable for the production of volatiles with strong odours that are noticed by the consumer.

Shoot regeneration from leaf explants of Withania coagulans (Stocks) Dunal and genetic stability evaluation of regenerates with RAPD and ISSR markers

Withania coagulans (Stocks) Dunal (Solanaceae) is a critically endangered medicinal plant known for its multiple medicinal properties. We report here an efficient and high frequency plantlet regeneration system through direct organogenesis in W. coagulans using in vitro-derived leaves as explants. On Murashige and Skoog's (MS) medium containing 4.44μM 6-benzylaminopurine (BAP) 73.7±4.3% explants responded and produced 11.4±0.9 shoot buds per explant. The regenerated shoot buds were elongated (6.7±0.22cm) on MS medium with 1.11μM BAP and 0.57μM indole-3-acetic acid (IAA). The elongated shoots were rooted both in vitro and ex vitro. The regenerates were acclimatized by slow and gradual exposure to different regimes of temperature and relative humidity. The leaf-regenerates were assessed for genetic stability using RAPD and ISSR molecular markers and confirmed true-to-type. The in vitro regeneration system developed would be useful for genetic restoration program as the overexploitation and reproductive failure forced W. coagulans towards the verge of complete extinction. The regeneration method would also be useful for genetic transformation for genetic improvement and improved phyto-pharming.

PROPAGATION OF Portulaca oleracea L. IN LIQUID MEDIUM: IMPLICATIONS OF PLANT GROWTH REGULATORS IN CULTURE

Portulaca oleracea L. is a medicinal plant, growing in warm and moist regions of north hemisphere of the world. A protocol for in vitro propagation using nodal shoot segments as explants has been outlined. The percent shoot response with shoot induction rate, 6.4 ± 0.7 shoots per explant, was achieved when cultured on agar-gelled Murashige and Skoog (MS) medium containing 2.0 mg/L of BAP (6-benzylaminopurine). The cultures were amplified by passages on MS medium with 1.0 mg/L each BAP and kinetin (Kn). The best shoot amplification (37.5±0.9 shoots per vessel) was achieved by subculturing of in vitro regenerated shoot clumps on liquid MS medium. Shoots regenerated in vitro by both the processes were rooted on ½ strength of MS medium + 2.0 mg/L of indole-3 butyric acid (IBA). Ninety six percent of the shoots rooted in vitro. The in vitro rooted plantlets were hardened under different regimes of temperature and humidity in the greenhouse. The hardened plantlets were transferred to mixture of soil and manure in polybags.

Internal decoherence of a Gaussian wave packet in a harmonic potential

We have studied the quantum dissipative problem of a Gaussian wave packet under the influence of a harmonic potential. A phenomenological approach to dissipation is adopted in the light of the well-known model in which the environment is composed of a bath of non-interacting harmonic oscillators. As one of the effects of the coupling to the bath is the evolution of an initially pure wave packet into a statistical mixture, we estimate the characteristic time elapsed for this to occur for different regimes of temperature, damping, and also different initial states.

Effect of temperature and strain rate on the deformation behavior and microstructure of a homogenized AZ31 magnesium alloy

The plastic deformation behavior and dynamic recrystallization (DRX) in homogenized AZ31 Mg alloy was investigated in uniaxial compression in the temperature range between 150 and 400°C with strain rates ranging from 10−3 to 102s−1. Twinning was found to contribute significantly during the early stages of deformation. The onset of twinning was examined in detail by recourse to the examination of the appearance of first local maxima before peak strain in the stress–strain responses and the second derivative of stress with strain. High strain hardening rate was observed immediately after the onset of twinning and was found to increase with the Zener–Hollomon parameter. DRX was observed at temperatures above 250°C whereas deformation at lower temperatures (<250°C) leads to extensive twinning at all the strain rates. At intermediate temperatures of 250–300°C, plastic strains tend to localize near grain/twin boundaries, confining DRX only to these regions. Increase in the temperature promotes non-basal slip, which, in turn, leads to uniform deformation; DRX too becomes uniform. Deformation behavior in three different regimes of temperature is discussed. The dependence of critical stress for the onset of DRX and peak flow stress on temperature and strain rate are also described.

Interacting fermions, boundaries, and finite size effects

In this work we analyze how effects of finite size may modify the thermodynamics of a system of strongly interacting fermions that we model using an effective field theory with four-point interactions at finite temperature and density and look in detail at the case of a confining two-layer system. We compute the thermodynamic potential in the large-$N$ and mean-field approximations and adopt a zeta-function regularization scheme to regulate the divergences. Explicit expansions are obtained in different regimes of temperature and separation. The analytic structure of the potential is carefully analyzed and relevant integral and series representations for the various expressions involved are obtained. Several known results are obtained as limiting case of general results. We numerically implement the formalism and compute the thermodynamic potential, the critical temperature and the fermion condensate showing that effects of finite size tend to shift the critical points and the order of the transitions. The present discussion may be of some relevance for the study of the Casimir effect between strongly coupled fermionic materials with inter-layer interactions.

Rates and mechanism of Y, REE, and Cr diffusion in garnet

Numerical simulation of the evolution of stranded diffusion profiles in partially resorbed garnet crystals from the aureole of the Makhavinekh Lake Pluton, Labrador, yields quantitative determinations of rates of diffusion of Y, rare earth elements (REEs), and Cr at ~700–900 °C, 0.53 GPa. Diffusion coefficients for these trivalent cations are 0.5–1.5 log 10 units smaller than those for major divalent cations measured in the same crystals, but diffusivities for trivalent cations are all equal to one another to within ±0.25 log 10 unit. Integration of these new data with previously published results resolves some prior inconsistencies, and defines the dependence of diffusivities for Y, the REEs, and Cr on temperature, pressure, and oxygen fugacity, while accounting for minor effects of ionic radius and host-crystal composition. Nd, Sm, and Eu—elements that are strongly depleted in rims of relict garnet crystals due to preferential partitioning out of garnet during resorption—evolve small but distinct maxima from initially nearly flat profiles; this “uphill diffusion” results from cross-coupling with Y and the other REEs, which are strongly concentrated in relict garnet rims by resorption. The weak dependence of diffusivity on ionic radius and host-crystal composition, the near-equivalence of diffusivities of Y+REEs with that of Cr, and the strong positive cross-coupling among Y+REEs are all explained by a diffusion mechanism that links the mobility of VIII Y+REEs with that of VI Al; this is likely a consequence of the dominance of the menzerite-(Y) component as a means of incorporating Y+REEs in the garnet structure. However, the variety of possible substitution mechanisms that may enable Y+REE incorporation into garnet, and the degree to which each may be favored in different regimes of temperature, pressure, and oxygen fugacity, imply a potential for great complexity, as the net diffusional flux may result from the superposed effect of multiple diffusion mechanisms, each with different kinetics.

Magnetotransport in La(Fe,Ru)AsO as a probe of band structure and mobility

In this work we investigate the Ru substituted LaFeAsO compound, by studying the magnetotransport behaviour and its relationship with the band structure, in different regimes of temperature, magnetic field and Ru content. In particular we analyse the magnetoresistance of LaFe1-xRuxAsO (0 <= x <= 0.6) samples with the support of ab initio calculations and we find out that in the whole series: (i) the transport is dominated by electron bands only; (ii) the magnetoresistance exhibits distinctive features related to the presence of Dirac cones; indeed, ab initio calculations confirm the presence of anisotropic Dirac cones in the band structure; (iii) the low temperature mobility is exceptionally high and reaches 18.6 m2/(Vs) in the Ru-free sample at T=2K, in the extreme limit of a single Landau level occupied in the Dirac cones; (iv) the mobility drops abruptly above 10K-15K; (v) the disorder has a very weak effect on the band mobilities and on the transport properties; (vi) there exists a correlation between the temperature ranges of Dirac cones and SDW carrier condensation. These findings may be of crucial importance in the investigation of the pairing mechanism in the F-doped superconducting La(Fe,Ru)As(O,F) compounds related to this series of parent compounds.

Germination of Miconia ligustroides (Melastomataceae) diaspores submitted to different treatments for dormancy overcoming

To assess the germination behavior of Miconia ligustroides (DC.) Naudin, diaspores were submitted to different regimes of temperature, light and substrate. Due to intrinsic low germination of the diaspores, they were submitted to treatments that aimed to overcome endogenous and exogenous dormancy. Miconia ligustroides presents complex dormancy and to overcome it is recommended to soak the diaspores in H2SO4 diluted at 75% for 5 minutes, wash it and then soak it in a solution of 400 mg L-1 of GA3 for 12 hours. Seeding should be done on Germtest® paper at 25 °C.