Parasitic Effects Research Articles

Theoretical Study for Carrier Transit Limited Performance of Gate-All-Around Si Nanowire Transistor by Time-Dependent Quantum Transport Simulation

Theoretically, the upper limit performance of nanoscale transistor should be limited by carrier transit time through the channel as the charge in channel cannot follow the gate voltage and the gate capacitance will show strong frequency dependence if the gate voltage varies faster than the carrier transit time. Currently, the operation frequency of nanoscale transistor is limited by the non-ideal factors such as parasitic effects, and it is far below the limit caused by carrier transit time. However, how good the transistor can be if one can minimize these non-ideal factors is still a problem, thus, it would be worth exploring its upper limit performance. In this article, time-dependent quantum transport simulation is performed to explore the carrier transit limited performance of the gate-all-around (GAA) Si nanowire transistor. By using the mode space approach, the 3-D time-dependent quantum transport equation is decoupled to a 2-D confinement problem and a 1-D transport problem, and then self-consistently solved with the Poisson’s equation. The transient characteristics of channel charge are investigated, and it shows the response time of channel charge is in the scale of 0.1 ps. The responses of channel charge and drain current to high-frequency gate voltages are simulated. The carrier transit limited performance including the frequency-dependent gate capacitance and transconductance, 3 dB bandwidth, and cutoff frequency, are calculated and discussed.

Molecular phylogenetics and systematics of two enteric helminth parasites (Baylisascaris laevis and Diandrya vancouverensis) in the Vancouver Island marmot (Marmota vancouverensis).

Island biogeography can promote rapid diversification and speciation via geographic isolation and novel selection pressures. These same factors can threaten the persistence of island endemics by limiting gene flow and suitable habitat. Host-parasite interactions on islands introduce another dimension of complexity as both species must simultaneously adapt to exogenous and endogenous factors. One example of host-parasite island biogeography is the critically endangered Vancouver Island (VI) marmot (Marmota vancouverensis) which is endemic to VI, Canada, and hosts two enteric helminth parasites: Baylisascaris laevis, an ascarid nematode common in tribe Marmotini, and Diandrya vancouverensis, an anoplocephalid cestode endemic to the VI marmot. Here, we aligned novel sequences from B. laevis (six genes) and D. vancouverensis (two genes) with congeneric sequences from GenBank. Phylogenies reconstructed using Bayesian and maximum parsimony approaches consistently placed B. laevis in a morphoclade, and D. vancouverensis in a monophyletic clade sister to D. composita. Mean pairwise sequence divergence between D. vancouverensis and D. composita (9.06±1.94%) surpassed commonly accepted thresholds for species delimitation, whereas divergence between VI and mainland populations of B. laevis (1.12±0.78%) was comparable to (or sometimes greater than) pairwise divergence values between other Baylisascaris species. Disparity in the genetic divergence of each parasite may reflect differences in their life cycle, host specificity, virulence, and the chronological extent of their isolation. Detailed descriptions of the population genetic structure and effects of both parasites on their shared host are crucial next steps in understanding the history of B. laevis and D. vancouverensis on VI and informing conservation efforts for the VI marmot and its enteric helminth parasites.

Monolithic GaN-Based Driver and GaN Switch With Diode-Emulated GaN Technique for 50-MHz Operation and Sub-0.2-ns Deadtime Control

In this article, the proposed monolithic gallium nitride (GaN)-based driver uses the diode-emulated technique to reduce reverse conduction through a meta-stable fast (MSF) comparator with sub-0.2-ns deadtime. In addition, an active bootstrap controller with a fast discharge loop is used to reduce parasitic effects to improve the driving capability, thereby increasing the switching frequency. Furthermore, the proposed gate driver with dual <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$dv/dt$ </tex-math></inline-formula> control can reduce the gate-ringing during turn-on/turn-off. Experimental results show that the GaN-based monolithic driver can achieve an operating frequency of 50 MHz and a slew rate of 120 V/ns. At 50 MHz, the conversion of 48-to-5 V can achieve a peak efficiency of 95.4% at the load current of 3.5 A.

Early Design/Technology Exploration of BEOL Options for Hybrid Wafer Bonded Split-SRAM

Traditional 2-D SRAM scaling has been slowing down and suffers from high parasitic resistance of critical signals like wordline (WL) and bitline (BL). As 3-D technologies such as hybrid wafer bonding (HWB) mature, increasingly finer pitches of 3-D interconnects are possible, enabling the possibility of 3-D partitioned memory designs. 3-D-split SRAMs, realized by splitting or folding an SRAM macro across two or more die stacks, may reduce the delay and power incurred inside the macro by mitigating the BL or WL signal RC parasitics. However, the efficacy of such a 3-D-split SRAM would depend on the parasitic overhead of the inter-tier 3-D back-end-of-line (3-D-BEOL) interconnects. We perform an early exploration of the BEOL options in the context of HWB and propose two separate approaches for optimizing the BEOL for 3-D-split SRAM designs. Measured results from 12 nm FinFET 64 kb prototype SRAM macros, designed in 2-D, but configured to capture the parasitic effects of 3-D-BEOL interconnects, indicate that 3-D-split SRAMs can provide 110–127 mV lower <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V} _{\text {MIN}}$ </tex-math></inline-formula> or 9%–14% faster access time, equivalent to the gains achieved with one full process node dimensional scaling.

Studying the Functioning of the Sensitive Element of a Capacitive Accelerometer with a Sandwich Structure under the Conditions of Parasitic Effects along the Nonworking Axes and Random Vibration

Studying the Functioning of the Sensitive Element of a Capacitive Accelerometer with a Sandwich Structure under the Conditions of Parasitic Effects along the Nonworking Axes and Random Vibration

Effects of parasitism by Pyemotes zhonghuajia on reproduction of potato tuber moth

Pyemotes zhonghuajia is an ectoparasitoid natural enemy of a wide range of pests such as Lepidoptera, Coleoptera and Hymenoptera. Phthorimaea operculella (Zeller) (PTM) is a worldwide potato pest with serious damage of potato production. Our study showed that one P. zhonghuajia female could kill 1st to 4th instar larvae of PTM, and the lethal time of one P. zhonghuajia female on first to fourth PTM instar larvae were 5.48, 11.33, 23.47 and 2076 min, respectively. The parasitism of 1, 3, 5, 10, and 20 P. zhonghuajia mites could significantly affect the mortality rate of PTM 4th instar larvae and pupae. The parasitism durations (30 and 60 mins) of one P. zhonghuajia female on one PTM fourth instar larva could influence the life history of PTM parental generation but did not influence the life table of PTM offspring generation. Releasing 60, 80, and 100 mites or opisthosoma with mites could reduce the occurrence and consumption of PTM on potatoes the weight loss of the potato tuber. The number of insect dung piles in one potato tuber was significantly decreased by releasing 60, 80, and 100 P. zhonghuajia mites, and releasing 100 mites resulted in the lowest number of insect dung piles. Our results indicate that P. zhonghuajia can significantly affect the population growth of PTM. Future studies should explore the lethal mechanism of P. zhonghuajia and its performance in practical application in the warehouse and field condition.&#x0D;

Correction method for calculating junction temperature considering parasitic effects in SiC MOSFETs

Correction method for calculating junction temperature considering parasitic effects in SiC MOSFETs

Experimental reduction of haemosporidian infection affects maternal reproductive investment, parental behaviour and offspring condition.

When hosts have a long coevolutionary history with their parasites, fitness costs of chronic infection have often been assumed to be negligible. Yet, experimental manipulation of infections sometimes reveals effects of parasites on their hosts, particularly during reproduction. Whether these effects translate into fitness costs remains unclear. Here, we present the results of an experimental study conducted in a free-ranging population of red-winged blackbirds (Agelaius phoeniceus) naturally experiencing a high prevalence of haemosporidian infections, with more than 95% of breeding adults infected with parasites from one or more haemosporidian genus. To assess effects of infection during reproduction, we manipulated adult red-winged blackbird females' parasite burden by administering an anti-haemosporidian medication before onset of egg-laying. Experimental reduction of infection resulted in significant benefits to mothers and their offspring. Medicated females laid heavier clutches, invested more in incubation and provisioning behaviour, and produced more fledglings than control females. Nestlings of medicated females had higher haematocrit, higher blood glucose, and lower reactive oxygen metabolites than nestlings of control females. Overall, our results provide evidence that, even in a species with high prevalence of infection, parasites can lead to decreased maternal investment and offspring quality, substantially reducing fitness.

Laser pulse cutoff at nonlinear reflection due to Raman backscattering in plasma.

A method for generating subrelativistic laser pulses with a sharp leading edge is proposed, which is based on Raman backscattering of an intense short pump pulse by a counter-propagating long low-frequency pulse propagating in a thin plasma layer. A thin plasma layer serves both to attenuate parasitic effects and to effectively reflect the central part of the pump pulse when the field amplitude exceeds the threshold value. A prepulse with a lower field amplitude passes through the plasma almost without scattering. This method works for subrelativistic laser pulses with durations up to 100 fs. The contrast of the leading edge of the laser pulse is determined by the seed pulse amplitude.

A Universal Electronically Controllable Memelement Emulator Based on VDCC with Variable Configuration

In this paper, a universal fractional order memelement (FOME) emulator is proposed based on the use of a voltage differentiating current conveyor (VDCC) as active block. The emulation circuit was implemented without an analog voltage multiplier and with only one type of grounded passive element—capacitors. Specially designed switching networks allow controlling the type of memelement and the emulator mode—floating or/and grounded, electronically controlled (by changing the bias voltage of the VDCC) FOMEs. The proposed emulator was theoretically analyzed, and the influence of possible non-idealities and parasitic effects was also been analyzed to reduce the undesirable effects by selecting the passive circuit elements. The proposed designs are very simple compared to most of the designs available in the literature and can operate in a wide frequency range (up to 50 MHz) and also satisfy the non-volatility test. All realized memelements can be used in incremental and decremental modes as well as in inverse configuration. The performance of the circuit was verified by HSPICE simulations using 0.18 μm TSMC process parameters and ±0.9 V power supply. The proposal is also supported by experimental results with off-the-shelf components (LM13700 and one AD844) in order to confirm the proposed solution’s workability.

The Infection of Paracalanid Copepods by the Alveolate Parasite Ellobiopsis chattoni Caullery, 1910 in a Subtropical Coastal Area

Paracalanid copepods, common in tropical zooplankton communities, are known hosts for a variety of parasites. Nevertheless, relatively little is known about the prevalence and consequences of parasitism in these copepods. In this study, we analyzed the relationship between two paracalanid copepods, Parvocalanus crassirostris and Paracalanus spp., with a common parasite, the alveolate protist Ellobiopsis chattoni, in a subtropical environment on the south-east Brazilian coast. We assessed the frequency and abundance of parasites in juveniles and adult male and female copepods. We observed that 22 out of 4014 Paracalanus spp. (0.55%) and 98 out of 3920 P. crassirostris were infected (2.5%). E. chattoni were rarely found in other taxa (about 0.05% for Oithona spp. and Acartia lilljeborgii). The parasites were most frequently attached to cephalosome appendages (73.6%), with up to four cells per copepod. The parasites were more prevalent in adults than juveniles, and adult females were more frequently infected than males. E. chattoni had a likely negative impact on copepod growth because the infected females were smaller than the non-infected females (p &lt; 0.001). Females are usually bigger and live longer than males, which could account for their high frequency of infection.

A Comprehensive Review on Amplification of Laser Pulses via Stimulated Raman Scattering and Stimulated Brillouin Scattering in Plasmas

The demand for high-intensity lasers has grown ever since the invention of lasers in 1960, owing to their applications in the fields of inertial confinement fusion, plasma-based relativistic particle accelerators, complex X-ray and gamma-ray sources, and laboratory astrophysics. To create such high-intensity lasers, free-running lasers were either Q-switched or mode-locked to increase the peak power to the gigawatt range. Later, chirped pulse amplification was developed, allowing the generation of peak power up to 1012 W. However, the next generation of high-intensity lasers might not be able to be driven by the solid-state technology alone as they are already operating close to their damage thresholds. In this scenario, concepts of amplification based on plasmas has the potential to revolutionize the laser industry, as plasma is already a broken-down medium, and hence does not pose any problems related to the damage thresholds. On the other hand, there are many other aspects that need to be addressed before developing technologies based on plasma-based amplification, and they are being investigated via theoretical and numerical methods and supported by several experiments. In this report, we review the prospects of employing plasma as the medium of amplification by utilising stimulated scattering techniques, such as the stimulated Raman scattering (SRS) and stimulated Brillouin scattering (SBS) techniques, to modulate high-power laser pulses, which would possibly be the key to the next generation of high-power lasers. The 1980s saw the commencement of research in this field, and possibilities of obtaining high peak powers were verified theoretically with the help of numerical calculations and simulations. The extent of amplification by these stimulated scattering schemes are limited by a number of instabilities such as forward Raman scattering (FRS), filamentation, etc., and here, magnetised plasma played an important role in counteracting these parasitic effects. The current research combines all these factors to experimentally realise a large-scale plasma-based amplifier, which can impact the high-energy laser industry in the near future.

The influence of support arms on the performance of vertical axis wind turbines

The vertical axis wind turbines (VAWT) are being used for small to medium-scale energy extraction, primarily for off grid applications. Several investigations on the VAWTs dealing with turbine blade optimisation and applications are reported. However, most of the literature have often neglected the effect of turbine arms during the numerical analysis, except a few. This study concerns the aerodynamic characteristics of support arm in 3D numerical predictions on the performance of a two-bladed VAWT with dual support arm configuration. Results with arms were compared against an ideal turbine with no support arms, which was set as the baseline. The numerical study with respect to power coefficients as well as characterisation of the turbine flow physics during turbine operations were conducted. The difference increased as the TSR value increased. The power coefficient comparisons saw a significant reduction in the predicted power coefficient due to the parasitic effect of the turbine arms. Both velocity and pressure contours showed that the turbine support arms' added consideration results in a much more turbulent flow around the turbine.

Electronically Tunable Current Mode Instrumentation Amplifier Employing Single DV-EXCCCII

In this paper, a new design of a current mode instrumentation amplifier (CMIA) is presented using a single differential voltage extra-X current controlled current conveyor (DV-EXCCCII) and a grounded resistor. Therefore, this circuit design is very simple and suitable for IC integration. The proposed circuit of instrumentation amplifier has high output impedance so it is easily cascadable with other current mode circuits without buffer requirement. Furthermore, the proposed circuit is electronically tunable with the bias current of the active element used. This circuit offers good frequency performance with wide differential gain and CMRR bandwidth. The non-idealities and parasitic effects of the proposed circuit are also investigated. To validate the proposed instrumentation amplifier, various simulations are performed using the CADENCE VIRTUOSO SPECTRE simulator using 0.18 µm CMOS technology parameters.

CMOS compatible manufacturing of a hybrid SET-FET circuit

This study analyzes feasibility of complementary metal–oxide–semiconductor (CMOS)-compatible manufacturing of a hybrid single electron transistor–field effect transistor (SET-FET) circuit. The fundamental element towards an operating SET at room temperature is a vertical nanopillar (NP) with embedded Si nanodot generated by ion-beam irradiation. The integration process from NPs to contacted SETs is validated by structural characterization. Then, the monolithic fabrication of planar FETs integrated with vertical SETs is presented, and its compatibility with standard CMOS technology is demonstrated. The work includes process optimization, pillar integrity validation, electrical characterization and simulations taking into account parasitic effects. The FET fabrication process is adapted to meet the requirements of the pre-fabricated NPs. Overall, this work establishes the groundwork for the realization of a hybrid SET-FET circuit operating at room temperature.

Effects of Parasitism on the Competitive Ability of Invasive and Native Species.

Parasitic plants can often seriously harm host plants and, thus, alter competitive dominance between hosts and neighbouring species. However, whether and how parasitic plants differently affect the competitive abilities of invasive and the native plants have not been tested. In this study, we used Cuscuta grovonii as the parasitic plants and three invasive plants and three native plants as host plants. Host plants grown alone or in competition with Coix lacryma-jobi were either parasitized with Cuscuta grovonii or not parasitized. Parasitism caused similar damage to invasive and native plants when grown with Cuscuta grovonii alone but caused less damage to invasive species than native species when grown in competition. Parasitism increased the competitive ability of invasive plants but did not affect the competitive ability of native plants. In the absence of parasitism, the competitive ability of host plants was significantly negatively correlated with the competitive ability of Coix lacryma-jobi, but under parasitism, there was no significant relationship of the competitive ability between host and competitor plants. Our results indicated that parasitic plants can increase the competitive tolerance of invasive plants, but have no effect on native plants. Thus, parasitism may play an important role in the process of plant invasion.

Resetting our expectations for parasites and their effects on species interactions: a meta-analysis.

Despite the ubiquitous nature of parasitism, how parasitism alters the outcome of host-species interactions such as competition, mutualism and predation remains unknown. Using a phylogenetically informed meta-analysis of 154 studies, we examined how the mean and variance in the outcomes of species interactions differed between parasitized and non-parasitized hosts. Overall, parasitism did not significantly affect the mean or variance of host-species interaction outcomes, nor did the shared evolutionary histories of hosts and parasites have an effect. Instead, there was considerable variation in outcomes, ranging from strongly detrimental to strongly beneficial for infected hosts. Trophically-transmitted parasites increased the negative effects of predation, parasites increased and decreased the negative effects of interspecific competition for parasitized and non-parasitized heterospecifics, respectively, and parasites had particularly strong negative effects on host species interactions in freshwater and marine habitats, yet were beneficial in terrestrial environments. Our results illuminate the diverse ways in which parasites modify critical linkages in ecological networks, implying that whether the cumulative effects of parasitism are considered detrimental depends not only on the interactions between hosts and their parasites but also on the many other interactions that hosts experience.

Nanocalorimetry using microscopic optical wireless integrated circuits

We present in situ calorimetry, thermal conductivity, and thermal diffusivity measurements of materials using temperature-sensing optical wireless integrated circuits (OWiCs). These microscopic and untethered optical sensors eliminate input wires and reduce parasitic effects. Each OWiC has a mass of ∼100 ng, a 100-μm-scale footprint, and a thermal response time of microseconds. We demonstrate that they can measure the thermal properties of nearly any material, from aerogels to metals, on samples as small as 100 ng and over thermal diffusivities covering four orders of magnitude. They also function over a broad temperature range, and we present proof-of-concept measurements of the thermodynamic phase transitions in both liquid crystal 5CB and gadolinium.

New Insights for Parasitic Effects of Label-Free Biosensors Based on Capacitive Micromachined Ultrasonic Transducers

Capacitive micromachined ultrasonic transducers (CMUTs) are regarded as an attractive candidate in bio-applications such as imaging and molecule monitoring. However, the previous researches on biochemical sensing are mostly air-coupled application based on a CMUTs array because cell-to-cell mutual radiation and large motional loss in liquid environment are able to produce nonignorable noise. For a CMUTs cell, its characteristics (e.g., electrical, mechanical, and acoustic) are susceptible to parasitic effects owning to the physically capacitive dielectric dispersion, motional damping, and connection loss. Neglecting the parasitic effects on multidomain characteristics of CMUTs leads to significant robustness errors. Furthermore, finite element method (FEM) is not sufficient enough to model such parasitic effects when considering an integrated circuit interface and the evaluation of system responses. This article highlights a lumped element model (LEM) to analyze the behaviors of a label-free biosensor based on a single CMUTs cell directly operating in liquid. We successfully explore the performance of the biosensor with different types of parasitic effects in transient and frequency domains through LEM and FEM. The parasitic effects on mass loading of sensing layer and biomolecule such as deoxyribonucleic acid (DNA) and Immunoglobulin G (IgG) probes are predicted by LEM based on their surface mass densities. The proposed approach is capable of analyzing the variation’s margin of CMUTs-based biosensors to improve robustness for parasitic extraction in liquid.

Can predators stabilize host-parasite interactions? Changes in aquatic predator identity alter amphibian responses and parasite abundance across life stages.

The role of parasites can change depending on the food web community. Predators, for instance, can amplify or dilute parasite effects on their hosts. Likewise, exposure to parasites or predators at one life stage can have long-term consequences on individual performance and survival, which can influence population and disease dynamics. To understand how predators affect amphibian parasite infections across life stages, we manipulated exposure of northern leopard frog (Rana pipiens) tadpoles to three predators (crayfish [Orconectes rusticus], bluegill [Lepomis macrochirus], or mosquitofish [Gambusia affinis]) and to trematode parasites (Echinostoma spp.) in mesocosms and followed juveniles in outdoor terrestrial enclosures through overwintering. Parasites and predators both had strong impacts on metamorphosis with bluegill and parasites individually reducing metamorph survival. However, when fish were present, the negative effects of parasites on survival was not apparent, likely because fish altered community composition via increased algal food resources. Bluegill also reduced snail abundance, which could explain reduced abundance of parasites in surviving metamorphs. Bluegill and parasite exposure increased mass at metamorphosis, which increased metamorph jumping, swimming, and feeding performance, suggesting that larger frogs would experience better terrestrial survival. Effects on size at metamorphosis persisted in the terrestrial environment but did not influence overwintering survival. Based on our results, we constructed stage-structured population models to evaluate the lethal and sublethal effects of bluegill and parasites on population dynamics. Our models suggested that positive effects of bluegill and parasites on body size may have greater effects on population growth than the direct effects of mortality. This study illustrates how predators can alter the outcome of parasitic infections and highlights the need for long-term experiments that investigate how changes in host-parasite systems alter population dynamics. We show that some predators reduce parasite effects and have indirect positive effects on surviving individuals potentially increasing host population persistence.