Error correcting method and apparatus Patent

Description of error correcting methods for use with digital data computers and apparatus for encoding and decoding digital dat

Effect of photoperiod on some biological parameters of Clarias gariepinus juvenile

Photoperiod effect on Growth parameters and cannibalism of Clarias gariepinushave been well documented in resent past, but little is known about the response of other biological parameters such as, Condition factor, Shooters composition, Body colouration and Blood glucose of this important tropical fish species to different photoperiods, therefore the present study was designed to evaluate these responses of the African catfish to 24 hours of light (00D:24L), 24 hours of darkness (24D: 00L) and 12 hour light / 12 hours darkness (12D: 12L). The six weeks experiment observed significant differences (P<0.05) in weight gain of the fish reared at the different photoperiods with the highest value of 92.20g+1.10 obtained in fishes reared under a photoperiod of twenty-four hours of darkness (24D: 00L) compared to those reared under a photoperiod of twelve hours of light and twelve hours of darkness (12D: 12L) which had 69.80g +2.50 and the least weight gain of 59.50g+8.2 was obtained under a twenty four hours of light (00D: 24L) photoperiod. Despite the stress induced by light which affected the weight gain of the fish, condition factor of the fishes in the different photoperiods did not vary significantly (P>0.05) at the end of the experiment and were Significantly lower than value obtained at the start of the experiment, Shooters composition was highest in 00D:24L (41.5% i.e. 27 of 65) leading to high mortality (13.33%) due to cannibalism compared to 12D: 12L (Shooters =15.27% i.e. 11 of 72, Mortality= 4%) and 24D: 00L (Shooters=5.33% i.e. 4 of 75, Mortality= 0%) photoperiod. More so, 93.33% (70 of 75) of fish in the dark phase (24D: 00L)exhibited Deep shiny black body colouration, while 6.67% (5 of 75) was observed of Normal fish colouration. However the fishes in the 00D: 24L photoperiod were observed to be predominantly Lighter skin colouration, (80% i.e. 52 of 65= lighter colouration, 18.46% i.e. 12 of 65= Normal skin coloration and 1.53 i.e. 1 of 65= Deep black body colouration) while 12D: 12L were of Normal skin colouration (100% Normal skin colouration), also blood glucose was observed to increase as the light hours increased (P<0.05) with 24D: 00L photoperiod having the highest blood glucose level of 5.7+0.5, while those in 12D: 12L had 4.4+0.3 and 24D: 00L had the least value of 3.9+0.1. This study therefore establishes the fact that photoperiod may have no effect on the condition factor of African catfish, while higher shooters composition is highlighted as one of the causes of increased mortality and could be reduced to a large extent with reduced light phase therefore enhancing higher survival, also the use of blood glucose as an indicator of stress in fish was justified in the present study

Dobinski-type relations: Some properties and physical applications

We introduce a generalization of the Dobinski relation through which we define a family of Bell-type numbers and polynomials. For all these sequences we find the weight function of the moment problem and give their generating functions. We provide a physical motivation of this extension in the context of the boson normal ordering problem and its relation to an extension of the Kerr Hamiltonian.Comment: 7 pages, 1 figur

Anomalous transport in disordered exclusion processes with coupled particles

We consider one-dimensional asymmetric exclusion processes with a simple attractive interaction, where the distance between consecutive particles is not allowed to exceed a certain limit and investigate the consequences of this coupling on the transport properties in the presence of random-force type disorder by means of a phenomenological random trap picture. In the phase-separated steady state of the model defined on a finite ring, the properties of the density profile are studied and the exponent governing the decay of the current with the system size in the biased phase is derived. In case all consecutive particles are coupled with each other and form a closed string, the current is found to be enhanced compared to the model without coupling, while if groups of consecutive particles form finite strings, the current is reduced. The motion of a semi-infinite string entering an initially empty lattice is also studied. Here, the diffusion of the head of the string is found to be anomalous, and two phases can be distinguished, which are characterised by different functional dependences of the diffusion exponent on the bias. The obtained results are checked by numerical simulation.Comment: 20 pages, 11 figure

Hierarchical Dobinski-type relations via substitution and the moment problem

We consider the transformation properties of integer sequences arising from the normal ordering of exponentiated boson ([a,a*]=1) monomials of the form exp(x (a*)^r a), r=1,2,..., under the composition of their exponential generating functions (egf). They turn out to be of Sheffer-type. We demonstrate that two key properties of these sequences remain preserved under substitutional composition: (a)the property of being the solution of the Stieltjes moment problem; and (b) the representation of these sequences through infinite series (Dobinski-type relations). We present a number of examples of such composition satisfying properties (a) and (b). We obtain new Dobinski-type formulas and solve the associated moment problem for several hierarchically defined combinatorial families of sequences.Comment: 14 pages, 31 reference

Atmospheric methanol measurement using selective catalytic methanol to formaldehyde conversion

International audienceA novel atmospheric methanol measurement technique, employing selective gas-phase catalytic conversion of methanol to formaldehyde followed by detection of the formaldehyde product, has been developed and tested. The effects of temperature, gas flow rate, gas composition, reactor-bed length, and reactor-bed composition on the methanol conversion efficiency of a molybdenum-rich, iron-molybdate catalyst [Mo-Fe-O] were studied. Best results were achieved using a 1:4 mixture (w/w) of the catalyst in quartz sand. Optimal methanol to formaldehyde conversion (>95% efficiency) occurred at a catalyst housing temperature of 345°C and an estimated sample-air/catalyst contact time of <0.2 seconds. Potential interferences arising from conversion of methane and a number of common volatile organic compounds (VOC) to formaldehyde were found to be negligible under most atmospheric conditions and catalyst housing temperatures. Using the new technique, atmospheric measurements of methanol were made at the University of Bremen campus from 1 to 15 July 2004. Methanol mixing ratios ranged from 1 to 5 ppb with distinct maxima at night. Formaldehyde mixing ratios, obtained in conjunction with methanol by periodically bypassing the catalytic converter, ranged from 0.2 to 1.6 ppb with maxima during midday. These results suggest that selective, catalytic methanol to formaldehyde conversion, coupled with existing formaldehyde measurement instrumentation, is an inexpensive and effective means for monitoring atmospheric methanol

Efficient C-H Bond Activations O_2 Cleavage by a Dianionic Cobalt(II) Complex

A dianionic, square planar cobalt(II) complex reacts with O_2 in the presence of acetonitrile to give a cyanomethylcobalt(III) complex formed by C-H bond cleavage. Interestingly, PhIO and -tolylazide react similarly to give the same cyanomethylcobalt(III) complex. Competition studies with various hydrocarbon substrates indicate that the rate of C-H bond cleavage greatly depends on the pK_a of the C-H bond, rather than on the C-H bond dissociation energy. Kinetic isotope experiments reveal a moderate KIE value of ca. 3.5 using either O_2 or PhIO. The possible involvement of a cobalt(IV) oxo species in this chemistry is discussed