Holstein polaron at fixed temperature: influence of the chain length

Based on the semiclassical Holstein model, the dynamics of a quantum particle in one-dimensional molecular chain with a trapping site is modeled. Numerical simulation is used to investigate the dynamics of a polaron in a chain with small random Langevin-like perturbations which imitate the thermostat. Parameter values are chosen such that the polaron energy at the trapping site is much greater than the energy of temperature fluctuations. Results of modeling demonstrate that temperature decay of a polaron depends on the chain length even at very low temperatures.

Windfield related light-trap catches of Nephotettix spp. (N. virescens Distant and N. nigropictus stål), vectors of rice tungro virus in West Bengal

ABSTRACT. Regular peak catches of rice green leafhoppers, Nephoteltix virescens (Distant) and N. nigropictus (Stal) are usually obtained in a light-trap 60 ± 14 days after the peak monsoon rains in August in West Bengal. In 1986, in addition to this peak catch, very high catches were obtained on two different dates, 17 September and 10 November. The high catch on 17 September was probably due to the increase of the effective trap radius caused by the overcast sky and by the presence of a resident population. The high catch on 10 November was due to the transport of the insects by cyclonic winds and deposition in a zone of light and variable winds (at a convergence) real the trapping site. Trajectory analysis indicates that these insects may have been brought from the north-east, upto about 280 km away from the trapping site.

Seasonal dynamics of Phlebotomus neglectus (Diptera: Psychodidae) in cave microhabitats in Romania and the rediscovery of Sergentomyia minuta (Rondani, 1843) after 50 years

Background In a countrywide study aiming to update the knowledge on diversity of sand fly species in Romania, a sand fly population was observed in an isolated system of cave microhabitats. The caves are located in the protected area of Canaraua Fetii, Dobrogea region, southeastern Romania. The highest sand fly diversity was recorded in this area between 1968 and 1970. This work presents a study conducted to estimate the seasonal variation of the sand fly species in correlation with the particular environmental factors of the isolated system of cave microhabitats. Methods Sand flies were collected between May and October 2020 from one trapping site of interest in Canaraua Fetii. The trapping site consisted of a cave entrance. CDC miniature light traps and sticky traps were used to collect insects from the exterior walls of the cave entrance. Species identification of collected sand flies was done using morphological keys. Statistical analysis of the trapping and climatic data was performed. Results From all collected sand flies, 99.7% (818/822) were Phlebotomus neglectus, 0.1% (1/822) Ph. balcanicus and 0.2% (2/822) Sergentomyia minuta. Sand fly activity was first observed on 2 July and last on 24 September. A monomodal abundance trend was present, with the peak activity between 16 and 17 July. The analysis of the climatic data showed correlations between the total number of captured sand flies and both average temperature and average relative humidity. The total number of collected specimens was statistically higher when CDC miniature light traps were used compared to sticky traps. The number of females on the sticky traps was significantly higher than the number of males on the same trap type. Compared with the sticky traps, significantly more males were collected by CDC miniature light traps. This is the first record of Se. minuta in Romania after 50 years of no records (despite the trapping effort of the last 5 years in the country). Also, Ph. sergenti, previously present in this location, was not found. Conclusions In the investigated natural habitat, the diversity of the sand fly species appears to have changed, with the predominance of Ph. neglectus instead of Ph. balcanicus and Se. minuta (recorded as the two predominant species in 1968–1970). A monomodal abundance trend was observed as in other regions of the country. The sand fly activity in this particular cave microhabitat appears to be longer than in other regions in Romania. Longer sand fly activity increases the zoonotic risk of various pathogenic species’ transmission, with an impact on public health, as sand flies are important insect vectors. Graphical abstract

Seasonality of Sand Flies (Diptera: Psychodidae) in Cave Microhabitats and The Rediscovery of Sergentomyia Minuta (Rondani, 1843) After Fifty Years

Background: In a countrywide study with the aim to update the knowledge on diversity of sand fly species in Romania, a sand fly population was observed in an isolated system of cave microhabitats. The caves are located in the protected area of Canaraua Fetii, Dobrogea region, southeastern Romania. The highest sand fly diversity was recorded at the above-mentioned area between 1968 and 1970. This work presents an abundance study, which was conducted in order to estimate the seasonal variation of the sand fly species in correlation with the particular environmental factors of the isolated system of cave microhabitats.Methods: Sand flies were collected between May and October 2020 from one trapping site of interest, from Canaraua Fetii. The trapping site consisted of a system of cave entrances. CDC miniature light traps, and sticky traps were used to collect insects from the exterior walls of the cave entrances. Species identification of collected sand flies was done using morphological keys. Statistical analysis of the trapping and climatic data was performed.Results: From all collected sand flies, 99.63% (818/821) were Phlebotomus neglectus, 0.12% (1/821) Ph. balcanicus, and 0.25% (2/821) Sergentomyia minuta. Sand fly activity was firstly observed in 2nd of July and lastly in 24th of September. A monomodal abundance trend was present, with the peak activity between 16th and 17th of July. The analysis of the climatic data showed correlations between the total number of captured sand flies and both, average temperature and average relative humidity. The total number of collected specimens was statistically higher when CDC miniature light traps were used compared to sticky traps. The number of females on the sticky traps was significantly higher than the number of males on the same trap type. When compared with the sticky traps, a significantly higher number of males were collected by CDC miniature light traps. This is the first record of Se. minuta in Romania after 50 years of no records (despite the trapping effort of the last five years in the country). Also, Ph. sergenti, previously present in this location, was not found.Conclusions: In the investigated natural habitat, the diversity of the sand fly species appears to have changed, with the predominance of Ph. neglectus instead of Ph. balcanicus and Se. minuta (recorded as the two predominant species in 1968-1970). A monomodal abundance trend was observed as in other regions of the country. The sand fly activity in this particular cave microhabitat appears to be longer than in other regions in Romania. A longer sand fly activity increases the zoonotic risk of various pathogenic species’ transmission, with an impact in the public health, as sand flies are important insect vectors.

Pyrazine-interior-embodied MOF-74 for selective CO2 adsorption

A series of pyrazine-interior-embodied MOF-74 composites (py-MOF-74) were successfully synthesized by a post vapor modification method, concomitant with the loading ratio of pyrazine easily controlled in this process. Here, pyrazine molecules perform as a cavity-occupant to block the wide pores of MOF-74, which accentuates the adsorption discrepancy of a pair of gases on MOFs and consequently reinforces the adsorption selectivity (typically for CO/N, CO/CH). Different from the “physical confinement” of occupants, pyrazine molecule with dual “para-nitrogen” atoms donates one N atom to bond with the open metal ion of MOF-74 for stability, and remains the other N atom available for potential CO trapping site. Pyrazine-interior-embodied MOF-74 composites manifest significantly improved CO/N and CO/CH adsorption selectivity. Typically, py-MOF-74c with ultimate pyrazine insertion displays selectivity greatly superior to MOF-74 in the equimolar CO/CH (598 vs. 35) and the simulated CO/N flue gas (471 vs. 49) at 100 kPa and 298 K.

New Deep Hole-Trapping Site for Water Splitting on Rutile TiO2(110) Surface

Mechanism of water photooxidation reaction on the rutile TiO2(110) surface has been extensively discussed but still remains highly controversial. By ab initio many-body Green’s function theory, we discover a new...

Microfluidic Device for the Analysis of Angiogenic Sprouting under Bidirectional Biochemical Gradients

In this paper, we developed a spheroid culture device that can trap a spheroid in the trapping site sandwiched by two extracellular matrix gels located at the upper and lower side of the spheroid. This device can form different biochemical gradients by applying target biochemicals separately in upper and lower channels, allowing us to study the angiogenic sprouting under various biochemical gradients in different directions. In the experiments, we confirmed the trapping of the spheroids and demonstrate the investigation on the direction and extent of angiogenic sprouts under unidirectional or bidirectional biochemical gradients. We believe our device can contribute to understanding the pathophysiological phenomena driven by chemical gradients, such as tissue development and tumor angiogenesis.

Numerical Evaluation on Analysis Methods of Trapping Site Density in Steels Based on Hydrogen Permeation Curve

Hydrogen permeation techniques have been widely utilized to extract hydrogen effective diffusivity, as well as hydrogen trapping site characteristics in steels. Several methods have been proposed to examine reversible and irreversible trapping site characteristics. However, the inappropriate utilization of these simplified models, as well as incorrect value assignment to the key parameters, can result in several orders of magnitude difference in hydrogen trapping site density. Therefore, in order to evaluate these models and verify their application prerequisites, a serial of hydrogen permeation tests were numerically simulated and examined, separately considering reversible and irreversible hydrogen trapping sites. In the meantime, suggestions were given to conduct hydrogen permeation test more effectively, and evaluate hydrogen trapping site characteristics more precisely.

The Efficiency of Live-Capture Traps for the Study of Red Fox (Vulpes vulpes) Cubs: A Three-Year Study in Poland

Safe and efficient techniques for the live capture of carnivores are limited. In this study, we identified some of the factors that could affect the success of capturing red fox cubs with live capture traps (also known as cage traps). During a three-year period, we analysed 32 captures of 25 fox cubs (1.3 captures/fox). We assessed the impact of the following factors: sex of animals, month of trapping, weather conditions recorded for each trap-night, the willingness of cubs to explore and enter cage traps, the researchers’ activity around den complexes before trapping and distances to the nearest village or farm. The overall trap rate (32 captures, including recaptured cubs) and the trap rate for individual cubs (25 captures) was 11.2 cubs/100 trap-nights and 8.7/100 trap-nights, respectively. Animals other than foxes were captured only three times, thus the selectivity of the cage-trapping method was high (32/35 = 91.4%). The probability of capturing one cub per night was 70.2% (32 cubs/47 nights). Cubs inhabiting dens in the vicinity of human settlements were less likely to explore and enter traps. Vixens were more likely to relocate their litters if the activity of the staff setting the traps was intense at the trapping site. The success of trapping was higher during poor weather as, for example, during rain or thunderstorms. None of the trapped animals suffered any injuries. Whereas cage trapping can be an effective and safe capture method for juvenile foxes, capture efficiency is affected by the experience of the trappers and a range of other factors including weather and distance to human settlements.

Photoinduced anisotropic distortion as the electron trapping site of tungsten trioxide by ultrafast W L1-edge X-ray absorption spectroscopy with full potential multiple scattering calculations

Ultrafast XANES spectra and full-potential multiple scattering reveal the anisotropic structure change of photoexcited WO3.