Relationship between total length and mouth gap of some commercially important carp fry

The estimated regression equation for total length and mouth gape computed were Log TL = Log 0.23 + 0.663 log MG (vertically) (r = 0.960) and Log TL = Log 0.08 + 0.686 log MG (horizontally) (r = 0.949). In case of rohu average total length from 11350 mm to 23775 mm and mouth gape 805 um to 1225 um (vertically) and 700 um to 1110 um (horizontally) between the first day of mouth opening up to 15 days. The regression equation for total length and mouth gap were Log TL = Log 0.20 + 0.660 log MG (vertically) (r = 0.935) and Log TL = Log 0.02 + 0698 log MG (horizontally) ( r = 0.907). In case of silver carp average total length from 12800 ,urn to 33555 um and mouth gape 690 um to 1210 um (vertically) and 615 um to 1115 um (horizontally) between the first day of mouth opening up to 15 days. The regression equation for total length and mouth gape were Log TL = Log 0.36 + 0.596 log MG (vertically) (r = 0.936) and Log TL = Log 0.26 + 0.607 log MG (horizontally) (r = 0.891). The relationship between total length and mouth gape (vertically and horizontally) of the studied fry were found to be linear and highly significant

Culture of pearl in freshwater mussels (Lamellidens marginalis Lamarck)

A pond trail on pearl culture in freshwater mussels, Lamellidens marginalis was carried out for one year in an artificial perennial pond. Four types of foreign particles of indigenous sources, sand, stone, fish eyeball and beads of artificial pearl nucleus were used as nucleus for pearl production. Among the nuclei inserted mussel highest survival rate (72%) was recorded for stone and lowest survival rate (50%) for artificial pearl by nucleus implantation. Highest pearl production rate (%) was recorded for the insertion of stone and lowest for the sand. All nuclei inserted mussel produced pearl accept the mussel which was inserted beads of pearl nucleus for pearl formation. Growth rate (length and weight) was found higher for uninserted mussel than nuclei inserted mussels

Electron-Spin Precession in Dependence of the Orientation of the External Magnetic Field

Electron-spin dynamics in semiconductor-based heterostructures has been investigated in oblique magnetic fields. Spins are generated optically by a circularly polarized light, and the dynamics of spins in dependence of the orientation (θ) of the magnetic field are studied. The electron-spin precession frequency, polarization amplitude, and decay rate as a function ofθare obtained and the reasons for their dependences are discussed. From the measured data, the values of the longitudinal and transverse components of the electrong-factor are estimated and are found to be in good agreement with those obtained in earlier investigations. The possible mechanisms responsible for the observed effects are also discussed

Geographical and temporal distribution of SARS-CoV-2 clades in the WHO European Region, January to June 2020

We show the distribution of SARS-CoV-2 genetic clades over time and between countries and outline potential genomic surveillance objectives. We applied three available genomic nomenclature systems for SARS-CoV-2 to all sequence data from the WHO European Region available during the COVID-19 pandemic until 10 July 2020. We highlight the importance of real-time sequencing and data dissemination in a pandemic situation. We provide a comparison of the nomenclatures and lay a foundation for future European genomic surveillance of SARS-CoV-2.Peer reviewe

The phylogeny and taxonomy of the parasitic wasp subfamily campopleginae (hymenoptera, ichneumonidae)

SIGLEAvailable from British Library Document Supply Centre-DSC:DXN026175 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Fecundity of guchibaim, Mastacembelus pancalus

Fecundity of guchibaim, Mastacembelus pancalus was described based on 100 samples collected from the experimental ponds of the Field Laboratory Complex, Faculty of Fisheries, Bangladesh Agricultural University, Mymensingh during the period from May to July 2007. The surveyed sample ranged from 115 to165mm in total length and 6.97±0.44 to 10.52±0.22g in average body weight. The ovary weight of the specimens varied from 0.77±2.61 to 5.19±0.29g. The fecundity was found to vary from 881.50±44.03 to 1182.30±27.33 eggs. The relationship between fecundity and total length was linear and it was expressed as: Y= 4.3927x+398.02 (R2=0.5336). The relationship between fecundity and body weight was linear and it was expressed as: Y= 67.319x+449.62 (R2=0.7446). The relationship between fecundity and ovary weight was also linear and it was expressed as: Y=72.36x+799.77 (R2=0.9189). The fecundity was highly correlated with the total length, body weight and ovary weight of fish and the Mastacembelus pancalus is a low fecund fish

Effect of pituitary gland doses on artificial propagation of Guchibaim, Mastacembelus pancalus (Hamilton)

Artificial propagation of Mastacembelus pancalus was conducted in order to determine the optimum dose of pituitary gland (PG) hormone at the hatchery of the Field Laboratory Complex, Faculty of Fisheries, Bangladesh Agricultural University, Mymensingh. The present study consisted of two trials and each trial had four treatments (T1, T2, T3 and T4, respectively) with three replications of each. In the experiment single dose and double dose had been used for T1, T2, T3 and T4, respectively to evaluate the efficiency on ovulation rate, fertilization rate, and hatching rate of M. pancalus eggs. The hatchlings were reared in aquarium up to 30 days and survival rate was determined. Treatment-3 (T3) of double dose (170mg PG kg-1 and 60mg PG kg-1 body weight of fish for female and male respectively) showed better results in terms of ovulation rate (90.03±2.56%), fertilization rate (90±0.81%), hatching rate (80±1.84%), and survival rate (40.00±3.19%) was recorded than other treatments of single and double dose. The water temperature was recorded 27 to 31°C. In the present study, treatment-3 (T3 in double dose) was the best findings in terms of ovulation rate, fertilization rate, and hatching rate which can be used in artificial propagation of M. pancalus for the development of hatchery production. May and June are the suitable months for artificial propagation of the said species

Embryonic and larval development of guchibaim , Mastacembelus pancalus (Hamilton)

The embryonic and larval development of local Guchibaim, Mastacembelus pancalus (Hamilton) was studied during May to October 2007. This study presents preliminary observations on the embryonic and larval development of Mastacembelus pancalus under laboratory conditions. The parents stock was collected from different places of Mymensingh district. The eggs were obtained through induction of spawning by use of hormones. At fertilization; the eggs were 0.50 mm in diameter. Samples were taken every 10 minutes interval till completion of morula and then every 1 hour interval up to hatching. After hatching, daily observations took place until the attainment of the fingerling stage. The eggs presented coloration varying from yellow to brownish-green. They were spherical, demersal and adhesive. The stages of embryonic development observed with cleavage, followed by blastula, morula, early gastrula, middle gastrula, late gastrula and until hatching of non-pigmented larvae which displayed total average length of 1.3 mm ± 0.22, 35 hours after fertilization. First cleavage was recorded within 1.05 hrs after fertilization and the embryonic rudiments of developing eggs appeared at 24.30 hrs at 27.0-31.0°C. The yolk sac was completely absorbed at 67 hrs during embryonic development on attainment of 5.50 mm total length. At the same time the digestive system became fully developed and the larvae searched for feeding