Discontinuities in the Electromagnetic Fields of Vortex Beams in the Complex Source/Sink Model

An analytical discontinuity is reported in what was thought to be the discontinuity-free exact nonparaxial vortex beam phasor obtained within the complex source/sink model. This discontinuity appears for all odd values of the orbital angular momentum mode. Such discontinuities in the phasor lead to nonphysical discontinuities in the real electromagnetic field components. We identify the source of the discontinuities, and provide graphical evidence of the discontinuous real electric fields for the first and third orbital angular momentum modes. A simple means of avoiding these discontinuities is presented.Comment: 10 pages, 4 figure

The impact of positive and negative psychological affect and overconfidence from major family events on new venture survival

This paper investigates how family events interacting with entrepreneurs’ psychological affect and overconfidence impact new venture viability. We use panel data from the Australian Household, Income and Labor Dynamics survey, focusing on family event-induced psychological affect entrepreneurs experience as a predictor of new venture survival. Our accelerated failure time model shows that although negative family events interact with entrepreneur overconfidence to spur cautious behaviour, positive events interacting with overconfidence have the biggest impact (negative) on new ventures. The study enhances our understanding of the embeddedness of family in the entrepreneurial process and challenges past research by revealing how positive family events can have a greater negative impact on new venture survival than negative ones

Perturbative representation of ultrashort nonparaxial elegant Laguerre-Gaussian fields

An analytical method for calculating the electromagnetic fields of a nonparaxial elegant Laguerre-Gaussian (LG) vortex beam is presented for arbitrary pulse duration, spot size, and LG mode. This perturbative approach provides a numerically tractable model for the calculation of arbitrarily high radial and azimuthal LG modes in the nonparaxial regime, without requiring integral representations of the fields. A key feature of this perturbative model is its use of a Poisson-like frequency spectrum, which allows for the proper description of pulses of arbitrarily short duration. This model is thus appropriate for simulating laser-matter interactions, including those involving short laser pulses

Variations of Physiological Parameters and HSP70 and HSP90 Polymorphisms in Water Buffaloes in Taiwan During Cool and Warm Season

Background: This study examined the physiological parameters of water buffaloes in Taiwan in the cool (February) and warm (August) seasons of 2020 and 2021. Methods: Data was collected for a study in February, August 2020, and 2021. The ambitious temperature, humidity, water buffaloes’ rectal temperature (RT), and respiratory rate (RR) were recorded. The plasma expression levels of heat-shock protein (HSP)70 and HSP90 were examined using an ELISA kit. Furthermore, the HSP70 and HSP90 fragment genetic sequence variations were analyzed using the PCR method and MEGA6 software. Results: The results revealed that in the warm season, the rectal temperature (RT), respiratory rate (RR), and heat tolerance coefficient (HTC) were significantly higher compared to the cool season (all P < 0.05). Additionally, the temperature-humidity index (THI) had moderate to high correlations with RT (0.518), RR (0.744), and HTC (0.757). Plasma HSP70 expression levels were higher in the warm season than in the cool season (P < 0.05). The genetic sequences of HSP70 and HSP90 fragments were compared, and five single-nucleotide variation (SNV) sites were identified. However, each genotype showed no significant physiological difference between the cool and warm seasons. Conclusion: Temperature and humidity changes in Taiwan had a significant correlation with the physical condition of water buffaloes. This information can be valuable in improving the living conditions of these animals, leading to better animal welfare. Additionally, the HSP70 and HSP90 gene variations in water buffaloes in Taiwan could be used as a reference for future research on breeding and identifying molecular markers

Enhancing high-order harmonic generation by sculpting waveforms with chirp

We present a theoretical analysis showing how chirp can be used to sculpt two-color driving laser field waveforms in order to enhance high-order harmonic generation (HHG) and/or extend HHG cutoff energies. Specifically, we consider driving laser field waveforms composed of two ultrashort pulses having different carrier frequencies in each of which a linear chirp is introduced. Two pairs of carrier frequencies of the component pulses are considered: (ω, 2ω) and (ω, 3ω). Our results show how changing the signs of the chirps in each of the two component pulses leads to drastic changes in the HHG spectra. Our theoretical analysis is based on numerical solutions of the time-dependent Schrödinger equation and on a semiclassical analytical approach that affords a clear physical interpretation of how our optimized waveforms lead to enhanced HHG spectra

Enhancing high-order-harmonic generation by time delays between two-color, few-cycle pulses

Use of time delays in high-order-harmonic generation (HHG) driven by intense two-color, few-cycle pulses is investigated in order to determine means of optimizing HHG intensities and plateau cutoff energies. Based upon numerical solutions of the time-dependent Schrõdinger equation for the H atom as well as analytical analyses, we show that introducing a time delay between the two-color, few-cycle pulses can result in an enhancement of the intensity of the HHG spectrum by an order of magnitude (or more) at the cost of a reduction in the HHG plateau cutoff energy. Results for both positive and negative time delays as well as various pulse carrier-envelope phases are investigated and discussed

Enhancing high-order-harmonic generation by time delays between two-color, few-cycle pulses

Use of time delays in high-order-harmonic generation (HHG) driven by intense two-color, few-cycle pulses is investigated in order to determine means of optimizing HHG intensities and plateau cutoff energies. Based upon numerical solutions of the time-dependent Schrõdinger equation for the H atom as well as analytical analyses, we show that introducing a time delay between the two-color, few-cycle pulses can result in an enhancement of the intensity of the HHG spectrum by an order of magnitude (or more) at the cost of a reduction in the HHG plateau cutoff energy. Results for both positive and negative time delays as well as various pulse carrier-envelope phases are investigated and discussed