NITROGEN STATUS AND ITS SUPPLYING CAPACITY OF TROPICAL SOILS

Total Nitrogen content in tropical soils is generally low compared to the mosttemperate soils. About 98% total nitrogen is associated with soil organic matterwhich in turn subjects to mineralization and hence releases mineral nitrogen to thesoil. Thereby most tropical soils nitrogen supplying capacity or nitrogenmineralization potential is relatively low and declines rapidly during croppingseason unless nitrogen sources are incorporated frequently. This investigationconducted to find out the nitrogen status, distribution of different nitrogenfractions and the mineralization potential of some selected agriculturallyimportant soils of Sri Lanka.Sixteen soils collected from various locations representing different soil typeswere analysed for total nitrogen. Eight soils from sixteen soils were fractionatedand ana lysed for different nitrogen forms viz; available N, ammonia-N, aminosugar-N, amino acid-N, acid hydrolyzable unknown N and acid insoluble-N afteracid hydrolysis. In a laboratory incubation experiment, those eight soils weresubjected to follow the nitrogen mineralization potential and to determine themineralization rates according to the method described by Stanford and Smith(1972). The nitrogen mineralization data during 315 days of inclubation wereused in Stanford and Smith's first order decay model to calculate nitrogenmineralization rate(k) and nitrogen mineralization potential (No).Total nitrogen contents in the studied soils varied from 89.36 (Aralaganwila) to365 mg/l00 g soil (NuwaraEliya). Soil organic matter contents also gave similarvariation and showed close relationship with total soil nitrogen. The distributionof different forms of soil nitrogen also varied among the soils studied. A majorpart of organic nitrogen in Sri Lankan soils was found to be associated with aminoacid-N fraction followed by the ammonia-N fraction. This was consistent withthe other studies conducted in elsewhere (Stevenson, 1957; 1982)Nitrogen mineralization rate was ranged from 0.0069 to 0.026 N mg/lOO soil perday. Highest mineralization rate was given by two paddy soils (Kiribathkumburaand Pilimathalawa). Nitrogen mineralizations potential or nitrogen supplyingpower also varied from 5.33 to 38.52 N mg/lOO g soil. High mineralizationpotential was also recorded in paddy soils. This may be attributed to the highorganic matter contents in those soils. Further these different nitrogen supplyingpowers of soils reflect their inherit characteristics or potential in supplyingavailable nitrogen for plant usage. One should give serious consideration to thoseparameters of soil nitrogen when nitrogen fertilizer recommendation practices areconducted for crops to attain optimum yield.

Acoustics in architecture: an examination of its role as an element contributing to the qualitative attributes of space

Architecture is inherently an art form of the body and all our senses. U creates a meaningful framework for the activities of the man by controlling and regulating the interrelationship between the man and his living environment. Since architecture should be an occasion of making a place by adding continuous articulation of human habitat, the reproduction of freestanding buildings will become an environmental destruction. So, an architect, beyond the authentic artist, must engage to make concrete the ideal view of life. Architecture, as meaningful buildings, should communicate its meaning through the organization of elements, which are considered as timeless and fundamental vocabulary in architecture. However, the required state of mind or the mood in architectural spaces could be generated through various combinations and relationships of so called spatial volumes In consideration of acoustics as an aesthetic element, the architect has before him the aesthetic problem of unfamiliar forms because, in architecture, beauty and familiarity are closely linked in a manner more binding than in other arts. However, in designing an acoustically favorable space, architect should recognize and use acoustic character as the basics of his idea. Although he has new materials, there is no other process of making it beautiful than the old process used by long ago by Greek Architects of contemplative design - emphasizing the essential character, economizing effects and adding ornaments. So, it is obvious that, the factors making for good or bad acoustics are not all new: some of them were most fundamental to buildings in old period and have been recognized in the past by acute designers such as the builders of Greek Theatres. When attention has been paid to special acoustic requirements, certain standard types of architecture have arisen such as classic theatres, the Leipzig concert hall, the Italian opera house, and the English House of Commons. These types have given satisfaction for generation So, the great history of architecture has to be touched to see the good performance of great architecture. They have been created through symbolic and emotional ideas of their traditions and the culture. Since the aesthetic experience is a matter of all our senses beyond the visual expression, the "aural environment" will be significant as an inherent attribute contributing to articulate human habitat in three-dimensional spatial volumes in architecture

RELEASE OF MINERALISED NITROGEN FROM SOILS AFTER INCORPORATION OF DIFFERENT ORGANIC MANURES

Use of organic manures as a nutrient source for crops is common practice inagriculture. Added advantages of using organic manures against syntheticfertilisers are the positive inf1uence on physico-chemical and biologicalcharacteristics of soils. Release of mineral nitrogen from organic manures couldbe used as an index to check the quality of organic manures in relation to nutrientsupply to the crops. Therefore, the objective of the present laboratory leachingstudy was to monitor the nitrogen release from soils after addition of selectedorganic manures.Two surface soils, Reddish Brown Earths and Non Calcic Brown (0-30cm)collected from Mahallluppallarna and Aralaganwila areas respectively, were usedin this study. Soils were mixed with three organic manures; Poultry manure(PM), Glyricidia leaves (GM) and Rice straw (RS) at the rate of 20 and 40tons/ha. There were four treatments; 1). Soil only - control, 2). Soil--Plvl. 3). Soil+GM and 4). Soil + RS. Each soil-organic manure mixture was placed inleaching columns and incubated in dark at room temperature. Mineralisednitrogen (NH+4 - N and NO) -N) was extracted with O.OIM CaCI2 solution at 7,14, 21, 35 and 49 days after incubation using the method described by Stanfordand Smith (1972). The NH\ -N and N03 - N contents were determined by usingstandard Kjeldhal method. The physico-chemical and nutritive characteristics ofsoils and organic manures were determined bv using standard laboratory methods.Results of the study revealed that the application of organic manures haspronounced effect on the release of nitrogen. In both soils, 40 tons/ha levelshowed higher release of nitrogen compared to 20 tons/ha level. Out of threeorganic manures, PM treated soils showed a higher release of nitrogen followedby GM treated soils. The RS treatment showed a very low release of nitrogenwhich is caused by the immobiolisation in two soils during the incubation. It wasvery clear that the release and immobilisation of nitrogen are controlled by theCIN ratios of organic manure. Up to 7th day the nitrogen release from PM andGM treated soils was high against the control as well as RS treated soils. After 7thto 2 Ith day, the mineralisation and release of nitrogen was ..decreased andsubsequently it was increased up to 35th day and then again decreased at the endof incubation with few exceptions. In general, the proportion of NH\ -N to NO) -N was high at the early stage of the incubation compared to the latter stage ofincubation. This may be attributed to the transformation of more NH+4 - N to N03-N by the nitrification process operating at the higher rate at the latter stage ofincubation. The release of NH -N and NO -N from organic manures wassignificantly higher than the control at certain sampling times. However,according to this study, the use of organic manures such as PM and GM with CINratios will enhance the mineral nitrogen content in soils during the first week ofincorporation.

Basic Rules of Aristotelian logic and Induction

We study comprehensive analysis of the inductive arguments done by various researchers. These researchers have surveyed the basic concepts in logic such as statement, argument, premise, conclusion, deductive argument, inductive argument, primitive terms and axioms. The fundamental laws of Aristotelian logic and Hume's critique of induction are briefly discussed. We argue that all the basic rules of Aristotelian logic are inductively obtained generalized abstract statements. Existence of undefined terms is also analyzed. We conclude that every argument based on Aristotelian logic is a result of induction

Methods of Reasoning in Scientific Discovery

In this paper, we briefly discuss the forms of arguments and the methods of reasoning in scientific experiments, namely, inductive reasoning, abductive reasoning and deductive reasoning. We find that generalization is in human nature, and it is only a conception without any perception. The short comings of the applications of deductive reasoning and inductive reasoning are analyzed using examples. It is observed that deductive reasoning and inductive reasoning methods are invalid in scientific reasoning. We discuss the vulnerability of the foundation of science that is based on the methods of inductive reasoning and deductive reasoning. We find that it is by abductive reasoning that theories are constructed to explain empirical observations. Abductive reasoning is only the reasoning method that can be applied for the observations in the empirical world. Finally, we conclude that the best and the most effective method of reasoning is the abductive reasoning for scientific experiments

n-Fold m-Valued Logic

In this paper, the basic concepts of two valued logic, many valued logic and catuskoti logic are discussed. We comprehensively analyzed the statement in different branches of logic. We define a ‘fold’ and a ‘statement’ in catuskoti. We further defined a ‘fold’ in general, a ‘multi valued statement’ and ‘ fold   valued logic’ (where  are integers greater than or equal to two). We identify that every branch of logic could be expressed in the form of fold  valued logic. We explain the problem of drawing a tangent to a curve and Zeon's arrow paradox by using the fold  valued logic. Truth tables for negation, conjunction, disjunction and implication in the fold  valued logic are discussed in this paper

Complete genome sequence of the Medicago microsymbiont Ensifer (Sinorhizobium) medicae strain WSM419

Ensifer (Sinorhizobium) medicae is an effective nitrogen fixing microsymbiont of a diverse range of annual Medicago (medic) species. Strain WSM419 is an aerobic, motile, non-spore forming, Gram-negative rod isolated from a M. murex root nodule collected in Sardinia, Italy in 1981. WSM419 was manufactured commercially in Australia as an inoculant for annual medics during 1985 to 1993 due to its nitrogen fixation, saprophytic competence and acid tolerance properties. Here we describe the basic features of this organism, together with the complete genome sequence, and annotation. This is the first report of a complete genome se-quence for a microsymbiont of the group of annual medic species adapted to acid soils. We reveal that its genome size is 6,817,576 bp encoding 6,518 protein-coding genes and 81 RNA only encoding genes. The genome contains a chromosome of size 3,781,904 bp and 3 plasmids of size 1,570,951 bp, 1,245,408 bp and 219,313 bp. The smallest plasmid is a fea-ture unique to this medic microsymbiont

Sequential induction of three recombination directionality factors directs assembly of tripartite integrative and conjugative elements

Tripartite integrative and conjugative elements (ICE3) are a novel form of ICE that exist as three separate DNA regions integrated within the genomes of Mesorhizobium spp. Prior to conjugative transfer the three ICE3 regions of M. ciceri WSM1271 ICEMcSym1271 combine and excise to form a single circular element. This assembly requires three coordinated recombination events involving three site-specific recombinases IntS, IntG and IntM. Here, we demonstrate that three excisionases–or recombination directionality factors—RdfS, RdfG and RdfM are required for ICE3 excision. Transcriptome sequencing revealed that expression of ICE3 transfer and conjugation genes was induced by quorum sensing. Quorum sensing activated expression of rdfS, and in turn RdfS stimulated transcription of both rdfG and rdfM. Therefore, RdfS acts as a “master controller” of ICE3 assembly and excision. The dependence of all three excisive reactions on RdfS ensures that ICE3 excision occurs via a stepwise sequence of recombination events that avoids splitting the chromosome into a non-viable configuration. These discoveries expose a surprisingly simple control system guiding molecular assembly of these novel and complex mobile genetic elements and highlight the diverse and critical functions of excisionase proteins in control of horizontal gene transfer

Aquaporin water channels in the nervous system.

The aquaporins (AQPs) are plasma membrane water-transporting proteins. AQP4 is the principal member of this protein family in the CNS, where it is expressed in astrocytes and is involved in water movement, cell migration and neuroexcitation. AQP1 is expressed in the choroid plexus, where it facilitates cerebrospinal fluid secretion, and in dorsal root ganglion neurons, where it tunes pain perception. The AQPs are potential drug targets for several neurological conditions. Astrocytoma cells strongly express AQP4, which may facilitate their infiltration into the brain, and the neuroinflammatory disease neuromyelitis optica is caused by AQP4-specific autoantibodies that produce complement-mediated astrocytic damage

Tsunami current inundation of ground with coastal vegetation effects; an initial step towards a natural solution for tsunami amelioration

A densely grown coastal vegetation belt of Pandanus odoratissimus to reduce the tsunami energy was quantitatively analyzed by an enhanced one-dimensional numerical model that included variations of topography and tsunami characteristics. The drag and inertia forces were assumed as the total resistance generated by the vegetation. A relatively small period tsunami wave was more destructive than a relatively large period tsunami wave of the same height, although densely grown vegetation effectively reduced the tsunami energy in the case of the small period tsunami wave. A very mild ground slope was more vulnerable to thrashing by tsunami waves than a relatively steep ground slope. Moreover, densely growing coastal vegetation on the very mild ground slope dissipated tsunami energy more efficiently than the same vegetation on the relatively steep ground slop