19 research outputs found
Heritability estimation for growth-related traits in juvenile wild common carp (Cyprinus carpio L.) in the south of Caspian Sea
Wild common carp of the Caspian Sea is one of the important fish in the north of Iran, which has been introduced to inland aquaculture. Its genetic characteristics are investigated to set up for breeding programs that are still unknown. Using wild common carp in aquaculture is limited for uncontrolled variation in performance of fish derived from undomesticated breeders. A 7×7 factorial mating design was employed to examine genetic effects of dam and sire on growth and heritability of growth-related traits based on dam half-sib and sire half-sib families. Breeders were obtained originally from the Caspian Sea. A total of 1470 offspring were raised in 49 separate fiberglass tanks with common conditions. Body weight and length were recorded at three different ages of rearing. Estimation of heritability of weights ranged from 0.23±0.05 to 0.30±0.07 for dams and ranged from 0.15±0.03 to 0.26±0.04 for sire. Similar results were obtained with length but with less variation (0.24±0.02 to 0.26±0.01 for dams and 0.20±0.02 to 0.22±0.03 for sire). The broad-sense of weight and length are 0.23±0.04 and 0.23±0.01 respectively. The dam and sire effect on growth were significant, indicating the presence of variations among the native fish of the Caspian Sea. Therefore, it is suggested to use a length for selection that is more reliable and less affected by environment than weight at any time of growth and in respect of high phenotypic correlation (0.87-0.95) observed between weight and length. In the present study we even used wild common carp and the heritability was not higher than the domesticated common carp. It means the genetic variation for quantitative traits, for common carp of the Caspian Sea are low or it may be under pressure of inbreeding which should be studied further
Manipulation of photoperiod in growth factors of beluga sturgeon Huso huso
The beluga sturgeon is considered as the most important species for caviar production. This study aimed to evaluate effects of photoperiod manipulation on growth factors of beluga sturgeon. The six photoperiod regimes (light: dark cycle) including natural photoperiod (control), 24L : 0D, 16L : 8D, 12L : 12D, 8L : 16D and 0L : 24D with the three replicates. The treatment 5 (8L: 16D) gained the greatest final weight (2194.4 g) after 73 rearing days and besides, the treatments 4, 3 and 1 (12L : 12D, 16L : 8D, and Control) can be considered as the good photoperiod regimes for beluga sturgeon. The continuous light (24L : 0D) and continuous dark (0L : 24D) significantly (P < 0.05) reduced the final weight of fish to 1804.2 g and 1976.1 g, respectively. Regulated photoperiod significantly improve growth rate and food conversion ratio of beluga sturgeon
Hardware-in-the-loop Proximity Operations in Cislunar Space
Space missions to Near Rectilinear Halo Orbits (NRHOs) in the Earth-Moon system are upcoming. A rendezvous technique in the cislunar space is proposed in this investigation, one that leverages coupled orbit and attitude dynamics in the Circular Restricted Three-body Problem (CR3BP). An autonomous Guidance, Navigation and Control (GNC) technique is demonstrated in which a chaser spacecraft approaches a target spacecraft in the southern 9:2 synodic-resonant L2 Near Rectilinear Halo Orbit (NRHO), one that currently serves as the baseline for NASA's Gateway. A two-layer control approach is contemplated. First, a nonlinear optimal controller identifies an appropriate baseline rendezvous path, both in position and orientation. As the spacecraft progresses along the pre-computed baseline path, optical sensors measure the relative pose of the chaser relative to the target. A Kalman filter processes these observations and offers precise state estimates. A linear controller compensates for any deviations identified from the predetermined rendezvous path. The efficacy of the GNC technique is tested by considering a complex scenario in which the rendezvous operation is conducted with a non-cooperative tumbling target. Hardware-in-the-loop laboratory experiments are conducted as proof-of-concept to validate the guidance algorithm, with observations supplemented by optical navigation techniques
Rendezvous in cislunar halo orbits: Hardware-in-the-loop simulation with coupled orbit and attitude dynamics
Space missions to Near Rectilinear Halo Orbits (NRHOs) in the Earth-Moon system are upcoming. A rendezvous technique in cislunar space is proposed in this investigation, one that leverages coupled orbit and attitude dynamics in the Circular Restricted Three-body Problem (CR3BP). An autonomous Guidance, Navigation, and Control (GNC) technique is demonstrated in which a chaser spacecraft approaches a target spacecraft in a sample southern 9:2 synodic-resonant L2 NRHO, one that currently serves as the baseline for NASA's Gateway. A two-layer guidance and control approach is contemplated. First, a nonlinear optimal controller identifies an appropriate baseline rendezvous path for guidance, both in position and orientation. As the spacecraft progresses along the pre-computed baseline path, navigation is performed through optical sensors that measure the relative pose of the chaser relative to the target. A Kalman filter processes these observations and offers state estimates. A linear controller compensates for any deviations identified from the predetermined rendezvous path. The efficacy of the GNC technique is tested by considering a complex scenario in which the rendezvous operation is conducted with an uncontrolled tumbling target. Hardware-in-the-loop laboratory experiments are conducted as a proof-of-concept to validate the guidance algorithm, with observations supplemented by optical navigation techniques
Sand fly synthetic sex-aggregation pheromone co-located with insecticide reduces the incidence of infection in the canine reservoir of visceral leishmaniasis: a stratified cluster randomised trial
The predominant sand fly vector of the intracellular parasite Leishmania infantum, that causes human and canine visceral leishmaniasis in the Americas, is Lutzomyia longipalpis. Dogs are the proven reservoir. Vector control tools to reduce transmission suited to this predominantly exophilic vector are lacking. Insecticide-impregnated dog collars protect dogs against infectious bites from sand fly vectors, and result in reductions of new infections in both dogs and humans. However, collars are costly for endemic communities, and alternative approaches are needed. Recently the bulk synthesised sex-aggregation pheromone of male Lu. longipalpis was shown to attract large numbers of conspecific females to lethal pyrethroid insecticides, indicating the potential for use in a vector control application. This study, conducted in Brazil, evaluated the efficacy of this novel lure-and-kill approach to reduce seroconversion and infection incidence with L. infantum in the canine reservoir, in addition to measuring its impact on household abundance of Lu. longipalpis. Deployed in 14 stratified clusters, the outcomes were compared to those attributed to insecticide impregnated collars fitted to dogs in another 14 clusters; each intervention was compared to 14 clusters that received placebo treatments. The beneficial effects of the lure-and-kill method were most noticeable on confirmed infection incidence and clinical parasite loads, and in reducing sand fly abundance. The overall effect of the two interventions were not statistically dissimilar, though the confidence intervals were broad. We conclude that the novel low-cost lure-and-kill approach should be added to the vector control toolbox against visceral leishmaniasis in the Americas
Report of urinary bladder rupture following obstructive urolithiasis in rams of Romanov sheep flock
Poor oral hygiene and risk of esophageal squamous cell carcinoma in Kashmir
Dar, N A Islami, F Bhat, G A Shah, I A Makhdoomi, M A Iqbal, B Rafiq, R Lone, M M Abnet, C C Boffetta, P eng Research Support, Non-U.S. Gov't England 2013/08/01 06:00 Br J Cancer. 2013 Sep 3;109(5):1367-72. doi: 10.1038/bjc.2013.437. Epub 2013 Jul 30.International audienceBACKGROUND: Several studies have suggested an association between poor oral health and esophageal squamous cell carcinoma (ESCC). We conducted a case-control study in Kashmir, a region with relatively high incidence of ESCC in north India, to investigate the association between oral hygiene and ESCC risk. METHODS: We recruited 703 histologically confirmed ESCC cases, and 1664 controls individually matched to the cases for age, sex, and district of residence. Conditional logistic regression models were used to calculate odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: We found an inverse association between teeth cleaning and ESCC risk. As compared with never cleaning teeth, the OR (95% CI) was 0.41 (0.28-0.62) for cleaning less than daily and 0.44 (0.25-0.77) for cleaning at least once a day (P for trend=0.026) in models adjusted for multiple potential confounders, including several indicators of socioeconomic status. This association persisted after we limited our analyses to never tobacco users. The inverse association between cleaning teeth and ESCC was stronger with using brushes than with using sticks/fingers. We also found an association between the number of decayed, filled, and missing teeth and ESCC risk, but the trend of the associations was not statistically significant. Avoiding solid food and cold beverages because of teeth and oral problems were also associated with ESCC risk. CONCLUSION: We found an association between poor oral hygiene indicators and ESCC risk, supporting the previous studies that showed the same associations