Adaptive RRI Selection Algorithms for Improved Cooperative Awareness in Decentralized NR-V2X

Decentralized vehicle-to-everything (V2X) networks (i.e., C-V2X Mode-4 and NR-V2X Mode-2) utilize sensing-based semi-persistent scheduling (SPS) where vehicles sense and reserve suitable radio resources for Basic Safety Message (BSM) transmissions at prespecified periodic intervals termed as Resource Reservation Interval (RRI). Vehicles rely on these received periodic BSMs to localize nearby (transmitting) vehicles and infrastructure, referred to as cooperative awareness. Cooperative awareness enables line of sight and non-line of sight localization, extending a vehicle's sensing and perception range. In this work, we first show that under high vehicle density scenarios, existing SPS (with prespecified RRIs) suffer from poor cooperative awareness, quantified as tracking error. Decentralized vehicle-to-everything (V2X) networks (i.e., C-V2X Mode-4 and NR-V2X Mode-2) utilize sensing-based semi-persistent scheduling (SPS) where vehicles sense and reserve suitable radio resources for Basic Safety Message (BSM) transmissions at prespecified periodic intervals termed as Resource Reservation Interval (RRI). Vehicles rely on these received periodic BSMs to localize nearby (transmitting) vehicles and infrastructure, referred to as cooperative awareness. Cooperative awareness enables line of sight and non-line of sight localization, extending a vehicle's sensing and perception range. In this work, we first show that under high vehicle density scenarios, existing SPS (with prespecified RRIs) suffer from poor cooperative awareness, quantified as tracking error

The system parameters of DW Ursae Majoris

We present new constraints on the system parameters of the SW Sextantis star DW Ursae Majoris, based on ultraviolet (UV) eclipse observations with the Hubble Space Telescope. Our data were obtained during a low state of the system, in which the UV light was dominated by the hot white dwarf (WD) primary. Eclipse analysis, using the full Roche lobe geometry, allows us to set firm limits on the masses and radii of the system components and the distance between them: 0.67 \leq M_1/M_sun \leq 1.06, 0.008 \leq R_1/R_sun \leq 0.014, M_2/M_sun > 0.16, R_2/R_sun > 0.28 and a/R_sun > 1.05. For q = M_2/M_1 < 1.5 the inclination must satisfy i > 71 degrees. Using Smith & Dhillon's mass-period relation for CV secondaries, our estimates for the system parameters become M_1/M_sun = 0.77 \pm 0.07, R_1/R_sun = 0.012 \pm 0.001, M_2/M_sun = 0.30 \pm 0.10, R_2/R_sun = 0.34 \pm 0.04, q =0.39 \pm 0.12, i = 82 \pm 4 degrees and a/R_sun = 1.14 \pm 0.06. We have also estimated the spectral type of the secondary, M3.5 \pm 1.0, and distance to the system, d =930 \pm 160 pc, from time-resolved I- and K-band photometry. Finally, we have repeated Knigge et al.'s WD model atmosphere fit to the low-state UV spectrum of DW UMa in order to account for the higher surface gravity indicated by our eclipse analysis. In this way we obtained a second estimate for the distance, d = 590 \pm 100 pc, which allows us to obtain a second estimate for the spectral type of the secondary, M7 \pm 2.0. We conclude that the true value for the distance and spectral type will probably be in between the values obtained by the two methods.Comment: 23 pages including 5 figures and 3 tables. Accepted for publication in Ap

Genetic regulation of diapause and associated traits in Chilo partellus (Swinhoe)

Diapause is an endocrine controlled arrested metabolic state to delay development or reproduction under unfavorable conditions. To gain an understanding of importance of diapause for ecological adaptation, it is important to study regulation of diapause in insects. We examined genetics of diapause in Chilo partellus by crossing the hibernating (HD), aestivating (AD), post-hibernating (PHD), post-aestivating (PAD), and nondiapause (ND) strains. Reciprocal crosses were also made to gain full understanding of diapause regulation and the maternal effects, if any. Data were recorded on fecundity, egg hatching, larval survival, diapause induction and termination, adult emergence, and morphometrics of larvae, pupae and adults in the parents (P1, P2), F1 hybrids, and the reciprocal crosses. Genetic analysis showed that AD strain is general combiner, which also improved egg hatching, larval survival, diapause termination, adult emergence and proportion of females in the progenies. Incidence of diapause was highest in HD × AD, whereas termination was greatest in PHD × AD. However, ND strain and its reciprocal crosses with other strains did not exhibit any noticeable developmental response associated with diapause. Specific combining ability analysis suggested that where PHD and AD strains exist together there will be likely reduction in diapause incidence, increased survival with greater fitness and faster multiplication of their progenies resulting in outbreak of C. partellus. Degree of dominance estimates revealed that diapause, developmental and morphometric traits in C. partellus are governed by over dominance gene effects, and mainly depend on parental diapause history

Temperature influences the performance and effectiveness of field and laboratory strains of the ichneumonid parasitoid, Campoletis chlorideae

To understand the influence of temperature on host-parasitoid interactions as a consequence of climatic change, we studied development, survival, and fecundity of field and laboratory strains of the Helicoverpa armigera larval endoparasitoid, Campoletis chlorideae at five different temperatures under laboratory conditions. Post-embryonic development period and degree-days required for completing the life cycle by both the strains decreased by 2.5 and 1.5 folds at 27°C compared to 18°C. Post embryonic development period showed a negative (r=-0.99, P<0.001) and the development rate a positive (r=0.99, P<0.001) association with an increase in temperature. However, no parasitoid larvae survived in H. armigera larvae reared at 12 and 35°C after parasitization, suggesting that temperatures ≥35°C as a result of global warming will be lethal for development and survival of immature stages of C. chlorideae. Adult longevity was negatively associated (r=-0.91 to -0.96, P<0.001) with temperatures between 12 and 35°C. The parasitoid adults stored at 12°C survived for longer period and exhibited higher fecundity than those kept at 27°C, but the efficiency of parasitism and adult emergence were quite low. Sex ratio of the progeny at 12°C was highly male-biased than the insects kept at 27°C. Laboratory strain of the parasitoid exhibited better survival, and the adults lived longer than the field strain at 18°C than at 27°C. Therefore, C. chlorideae adults stored at 18°C could be used for parasitism, while the immature stages should be reared at 27°C for mass production of the parasitoid for biological control of H. armigera

Comparative studies on the effects of Bt-transgenic and non-transgenic cotton on arthropod diversity, seedcotton yield and bollworms control

The effectiveness of commercial Bt-cotton in pest management, influence on arthropod diversity, natural enemies, and toxin flow in the insect fauna under field conditions were studied keeping in view the need to assess bioefficacy and biosafety of Bt-transgenic cotton. There were no significant differences in oviposition by Helicoverpa armigera on Bt-transgenic and non-transgenic cottons (9.2 versus 9.6 eggs plants-100), while the numbers of H. armigera larvae were significantly more on non-transgenic than on Bt-transgenic (10.4 versus 4.0 larvae plants-100) cotton. The Bt-cotton had significantly more number of mature opened bolls (9.6 versus 4.4 bolls plant-1), lower bollworm damage (12.8 versus 40.2% bolls damaged), and higher seedcotton yield (667.7 versus 231.7 kg ha-1). Population of cotton leafhopper, Amrasca biguttula biguttula was lower (582.2 versus 732.2 leafhoppers plants-100), while that of whitefly, Bemisia tabaci was higher on Bt-transgenic (65.2 versus 45.6 whiteflies plants-100) than on non-transgenic cotton. There was no significant influence of Bt-transgenic cotton on abundance of natural enemies of crop pests – chrysopids (9.6 versus 8.4 chrysopids plants-100), ladybird beetles (16.0 versus 10.8 ladybirds plants-100), and spiders (128.4 versus 142.8 spiders plants-100). There were no significant differences in H. armigera egg (19.8 versus 20.9%), larval (7.4 versus 9.6%), and larval-pupal (1.3 versus 2.9%) parasitism on Bt-transgenic and non-transgenic cottons in the farmer’s fields. The parasitism in larvae of H. armigera was far lower than that of the eggs, which might be because of early mortality of H. armigera prior to parasitoid development in the host larvae. Although, Cry1Ac Bt toxin was detected in Cheilomenes sexmaculatus, chrysopids, A. bigutulla bigutulla, Thrips tabaci, Myllocerus sp., Oxycarenus laetus, Dysdercus koenigii, spiders, bugs, and grasshoppers, no significant differences were observed in their abundance on Bt-transgenic and non-transgenic cottons, suggesting that there were no adverse effects of Bt-cotton on the arthropod diversity under field conditions

Impact of Bt-engineered cotton on target and non-target arthropods, toxin flow through different trophic levels and seedcotton yield

Insect-resistant genetically engineered cottons expressing ?-endotoxins from the bacterium, Bacillus thuringiensis (Bt) have been adopted on a large scale worldwide. The effects of Bt cotton on non-target insect pests, generalist predators, arthropod diversity and toxin flow through different trophic levels under insecticide protected and unprotected conditions was studied. The populations of major non-target insect pests (leafhoppers, whiteflies, ash weevils, aphids, dusky and red cotton bug, and green bug) and the generalist predators (ladybirds, chrysopids, and spiders) did not differ significantly between the Bt and non-Bt cottons, while their numbers were lower in insecticide protected than under unprotected conditions, except for aphids and whiteflies. Although, Bt toxin was detected in some insect species, no significant differences were observed in their abundance on Bt and non-Bt cottons. Species richness and diversity of plant inhabiting and soil dwelling arthropods was similar in Bttransgenic and non-transgenic cottons, except in a few cases. The Bt-transgenic cotton was effective for the management of bollworms, without any major adverse effects on the non-target arthropods

Effect of storage temperature and duration on viability of eggs of Helicoverpa armigera (Lepidoptera: Noctuidae)

The ability to store different insect stadia for prolonged periods provides considerable flexibility and ability to conduct experiments properly. Therefore, studies were undertaken to determine the effect of storage temperature and duration on viability of eggs of Helicoverpa armigera (Hübner). The percentage egg hatch and incubation period were significantly (P=0.01) influenced by egg age, storage temperature, and storage duration. Egg hatch ranged from 0.0 to 96.8% across temperatures and storage durations. None of the eggs hatched when stored at -20 and 0°C. The regression model with the optimum Mallow Cp statistic for any of the identified linear and quadratic terms did not improve the precision of prediction in egg hatch beyond 67.0%. Forecasting of incubation period based on egg age, storage duration, and duration × temperature was quite effective (R2=84.2%). Day degrees required for egg hatching decreased with an increase in temperature from 10 to 27°C, and egg age from 0 to 3 days. The day degree requirements were highest for 0-day-old eggs at 10°C, and lowest at 27°C. Although the incubation period was higher, the hatchability was lower for 0- and 1-day-old eggs stored at constant 10°C, these eggs can be stored for 10 days at 10°C, with a hatchability of >75.0%. It was safer to store the H. armigera eggs for 10 days at 10°C, which will hatch within 1.6 to 2.0 days after restoration at 27°C with a hatchability of >75.0%. This information will be useful in planning and execution of experiments involving H. armigera on various aspects of research in entomology

Influence of mating and oviposition behavior on progeny production of the ichneumonid parasitoid, Campoletis chlorideae

The Campoletis chlorideae Uchida is an important natural enemy of the noctuids, being the most important larval parasitoid of Helicoverpa armigera (Hubner) in different agro-ecosystem. Regulation of sex ratio in the hymenopterans has an important bearing on the use of natural enemies for the management of insect pests. There is no clear concept of sex ratio manipulation by C. chlorideae, therefore the present studies were conducted to understand the mechanism of sex ratio in C. chlorideae in 4 different mating schemes. Mating and parasitization regimes had a significant influence on the fecundity of C. chlorideae females, while no significant differences were observed for cocoon formation, adult emergence, and larval and pupal periods across mating regimes. There was a positive correlation (r = 0.68) between fecundity and longevity of C. chlorideae females. Attraction of more males to copulating pair resulted in mating of a female with two or three males simultaneously, suggested increased release of sex pheromone by the females during copulation and the competition among the males for mating. However, mating with multiple males simultaneously is not an additive advantage in progeny production, since only 20% of the C. chlorideae females (mated with two males) were able to parasitize the H. armigera larvae successfully. There was no consistent trend in sex ratio across treatments and parasitization days, except in case of unmated females. Studies on sexual and ovipositional behaviors suggested that extrachromosomal factors could be responsible for sex-determination in C. chlorideae, which needs to be tested systematically

Genetically Modified Organisms for Pest Management: Environmental Impact

Recombinant DNA technology has been exploited to develop genetically modified organisms (GMOs) for pest management that retain the advantages of classical biological control agents, but have fewer or none of their drawbacks. Genes conferring resistance to insects, particularly the 5-endotoxin genes from the bacterium, Bacillus thuringiensis have been inserted into several crop plants, of which insect-resistant cotton, maize, rice, tomato, and potato have been deployed commercially on a large-scale for pest management. Genetic engineering techniques can also be used for producing robust natural enemies, and more stable and virulent strains of bacteria, fungi, viruses, protozoa, and nematodes for use in integrated pest management. Deployment of insect-resistant transgenic plants for pest control will lead to a substantial reduction in insecticide use, reduced exposure of farm labor to insecticides, reduction in harmful effects of insecticides to nontarget organisms, and reduced amounts of insecticide residues in food and food products. Gene introgression through transgenic approach could also be beneficial in the sense that it adds diversity to the genetic pool of the crop plants. However, transgenics are not a panacea for solving all the pest problems, and concerns regarding the biosafety of GMOs to the environment are still inconclusive, and there is a continuous debate regarding their nontarget effects in the environment. There is a concern that large-scale deployment of GMOs for pest management might influenc