12,795 research outputs found
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
Kokybės užtikrinimo plėtra Bosnijos ir Hercegovinos aukštojo mokslo sektoriuje: teksto analizė
Education is the bedrock of any nation. It is essential for individual and societal growth and development. This study investigates the role of quality assurance in achieving the expected outcome of education in Bosnia and Herzegovina’s higher education sector. A textual analysis is used to examine the National Qualification Framework. The study is based on a documented review and descriptive analysis of student enrollment and programs of studies. The textual analysis is largely qualitative in nature. Unlike the global trend, it can be seen that student enrollment is on the decline in Bosnia and Herzegovina. It was found that quality assurance is an indispensable tool for strengthening the higher education sector and for achieving the desired change and outcomes that education offers. It was also found that study programs and curricula are pivotal for teaching and learning processes, and that a unified qualification framework is essential for achieving set objectives of education at all levels. The study recommended that sound quality assurance systems as well as an appropriate structure for monitoring and accreditation be put in place and be judiciously followed in order to achieve the desired outcomes in conjunction with the set objectives of higher education in the country. Moreover, certain pressures (i.e., democratic, economic, and systemic) and obstacles are looked at that show signs of epistemological, political, and institutional barriers that Bosnia and Herzegovina faces as a developing country Europeanizing its system of education.Švietimas yra kiekvienos tautos pagrindas, būtinas asmens ir visuomenės augimui bei vystymuisi. Šiame tyrime analizuojamas kokybės užtikrinimo vaidmuo siekiant numatomų Bosnijos ir Hercegovinos aukštojo mokslo sektoriaus rezultatų. Nacionalinė kvalifikacijų sistema nagrinėjama pasitelkiant teksto analizės metodą – tyrimas grindžiamas dokumentuota, daugiausia kokybine studentų priėmimo ir studijų programų apžvalga bei aprašomąja analize. Tyrimas atskleidė, kad skirtingai nuo pasaulinių tendencijų, Bosnijoje ir Hercegovinoje studentų skaičius mažėja. Kokybės užtikrinimas yra nepakeičiama priemonė stiprinant aukštojo mokslo sektorių, taip pat norint pasiekti švietimo inicijuojamus pokyčius ir rezultatus. Atskleista ir tai, kad studijų programos ir ugdymo turinys turi lemiamą reikšmę mokymo ir mokymosi procesams, o unifikuota kvalifikacijų sistema yra būtina siekiant užsibrėžtų švietimo tikslų visais lygiais. Tyrime rekomenduojama įdiegti patikimas kokybės užtikrinimo sistemas, atitinkamą stebėsenos ir akreditavimo struktūrą bei jų apgalvotai laikytis, kad šalyje būtų pasiekti keliamus aukštojo mokslo tikslus atitinkantys rezultatai. Be to, tyrime aptariami labai svarbūs ir nuodugniai išanalizuoti lemiami veiksniai (demokratiniai, ekonominiai ir sisteminiai) ir trikdžiai – jie nusako epistemologinių, politinių ir institucinių kliūčių požymius Bosnijoje ir Hercegovinoje, besivystančioje šalyje, kuri yra švietimo sistemos europinimo pavyzdys
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
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