Tide Guide (A graphical method of estimating height of tide at a given time or the time at which tide attains a required height in water areas subject to semidurnal tides)

This paper first describes and examines briefly various methods available to a navigator, port official or operator, etc., for determining height of tide at a given time and/or the time at which the tide will attain a given (required) height in water areas which are subject to semidiurnal tides. It then introduces a new graphical method for determining these two variables (height or time). Finally, it compares the results obtained by these methods and shows that the new method gives results within acceptable limits. Because of the complete absence of calculations and ease of use, this new method should be readily acceptable to users

Post-Civil War Democratization: Domestic and International Factors in Movement Toward and Away from Democracy

Post-civil war democratization is a critical element of building sustainable peace in the post-civil war states. At the same time, studies of democratic transition and survival suggest that the post-civil war environment is not hospitable to either the transition to or survival of democracy. The post-civil war environment is contentious. Former protagonists are fearful about their security and at the same time they want to protect their political and economic interests. The central argument of this study is that former rivals can agree to a transition toward democracy to the extent that a stable balance of power exists between the government and rebel groups, a balance that eliminates the sort of security dilemma that would encourage one or both to resume armed conflict. And the balance should ensure access to political power and economic resources. This study identifies factors that contribute to the establishment of such a balance of power between former protagonists and factors that affects its stability. These factors should affect the decision of former protagonists on whether or not they can achieve their political and economic interests if they agree to a transition toward democracy once civil war ends. Factors that are conducive to a transition toward democracy are different from factors that sustain that transition in post-civil war states. Post-civil war democracies are fragile. The side that won the democratic election can dismantle institutions of democracy and repress oppositions. The fear of being repressed could create stronger incentives for the opposition groups to return to conflict. To address this puzzle, I develop a conceptual framework that explains how costs of the previous civil war, the establishment of inclusive institutions and the higher level of economic development create incentives for the former rivals to sustain democracy. Hypotheses derived from the theoretical implications are tested by using survival analysis

Graphene: a game changer in prosthodontics and implant dentistry

Graphene family nonmaterial, with supercilious mechanical, chemical, and biological properties, have grabbed attention on the path of researches seeking newer materials for future biomedical applications. Although potential applications of graphene had been highly reviewed in other fields of medicine, especially for their antibacterial properties and tissue regenerative capacities, in vivo and in vitro studies related to prosthodontics are very limited. Therefore, based on current knowledge and latest progress, this article aimed to present the recent achievements and provide a literature review on potential uses and applications of graphene that could be converted into clinical reality in prosthodontics

On the communication of well-being

The form that any communicatory exchange takes would depend on the extent to which the interests of the signaller and the recipient are at variance. Where such interests coincide, i.e. in cases of mutualism, the signals may be conspicuous when an immediate response is favoured, but rather subtle and variable otherwise. Over 80 % of the events of tactile communication that we have noted in our study of the social behaviour of free ranging groups of tame elephants appear to belong to this latter category. On Smith's standard classification, they can only be classified as 'associative', related to remaining in the company of another individual. However, such signals are commoner by a factor of 20-100 amongst elephant calves and their mothers and allomothers when compared to exchanges between adult cows. We suggest that the function of these signals is mutual monitoring of the state of well being amongst related individuals. The considerable degree of altruistic behaviour displayed in social groups, such as those of elephants is now believed to subserve the function of enhancing the inclusive fitness of the individuals concerned. We explore a mathematical model of exchange of social aid which suggests that animals in social groups may enhance their inclusive fitness further by adjusting the amount of social aid exchanged in relation to the state of well being of the donor as well as the recipient. Our model further suggests that optimal social aid depends on the state of well being in a complex fashion making it difficult for the recipient to deceive the donor so as to extract more aid. We therefore expect that by and large honest communication of the state of well being would be characteristic of the higher social animals. Such communication would be based on normal physiological changes consequent on a change in well being. Thus animals with a superior degree of well being would take postures conducive to greater activity, would be more receptive to sensory inputs and may also shift the balance of production of various metabolites. This monitoring of the well being has greatly advanced in the human species and may be at the base of the elaborate health care amongst human societies

Observations on the natural history and population ecology of the social wasp Ropalidia marginata (Lep.) from Peninsular India (Hymenoptera: Vespidae)

Ropalidia marginata, the most common Indian social wasp, belongs to a crucial stage of social evolution showing no obvious morphological caste differentiation but a behavioural caste differentiation and a dominance hierarchy that appears to influence division of labour. The nests consist of a single open comb that can sometimes have up to 500 cells and 10 pedicels. Nests are initiated and abandoned all round the year. Initiation is by 1-20 foundresses, 1-4 being the most common number. There is a great deal of variation in brood developmental times both within and between nests. Male progeny disappear from the nest soon after emergence while daughters stay on at the parent nest for a mean period of about a month. Small nests have a single egg layer while large nests have two or more females with well developed ovaries that presumably lay eggs. Most nests are short-lived, small nests being highly susceptible to failure. Large nests are less susceptible to failure but the emergence of multiple egg layers reduces the average relatedness of workers to the brood which presumably is the cause for large scale emigrations from these nests. An interaction of ecological and soical factors therefore appears to determine the growth of a nest

Gravitational Collapse of Inhomogeneous Dust in (2+1) Dimensions

We examine the gravitational collapse of spherically symmetric inhomogeneous dust in (2+1) dimensions, with cosmological constant. We obtain the analytical expressions for the interior metric. We match the solution to a vacuum exterior. We discuss the nature of the singularity formed by analyzing the outgoing radial null geodesics. We examine the formation of trapped surfaces during the collapse.Comment: Accepted for publication in CQ

Impact of human extraction on tropical humid forests in the Western Ghats Uttara Kannada, South India

1. Thirty strip transects of 2400 m2 each, in the evergreen forest tract of the district of Uttara Kannada in South India; were clustered into two groups with high and low levels of disturbance on the basis of the density of perennial flowering plants and the fraction of deciduous species. 2. The set of 20 transects corresponding to low disturbance localities harboured 48 ± 6 (mean ± SD) species and 694 ± 135 individuals per transect, while the other 10 transects affected by high levels of disturbance supported 36 ± 12 species and 379 ± 135 individuals. 3. Eighty-four of the total of 200 species (operational taxonomic units) were exclusive to sites of low disturbance, and 28 to those of high disturbance; 88 species were shared by sites of high and low disturbance. This number of shared species was significantly less than expected on the basis of chance alone. 4. The differences in species richness, as well as those in species turnover (0.73 ± 0.07 for high and 0.65 ± 0.01 for low disturbance sites) were significant at the 1% level, but were as expected given the lower plant densities at sites of high disturbance. 5. Lack of coppicing ability in conjunction with their use in the plywood/matchwood industry has led to the disappearance of several evergreen species such as Syzigium gardneri and Myristica malabarica at sites with high levels of disturbance. 6. With villagers concentrating on harvests of trees in the height class of 4-8 m as poles, and commercial interests mostly extracting trees > 16 m in height, there was a reduction of around 45% across all height classes between sites of low and high levels of disturbance

Gravitational collapse in asymptotically Anti-de Sitter/de Sitter backgrounds

We study here the gravitational collapse of a matter cloud with a non-vanishing tangential pressure in the presence of a non-zero cosmological term. Conditions for bounce and singularity formation are derived for the model. It is also shown that when the tangential pressures vanish, the bounce and singularity conditions reduce to that of the dust case studied earlier. The collapsing interior is matched with an exterior which is asymptotically de Sitter or anti de Sitter, depending on the sign of cosmological constant. The junction conditions for matching the cloud to exterior are specified. The effect of the cosmological term on apparent horizons is studied in some detail, and the nature of central singularity is analyzed. We also discuss here the visibility of the singularity and implications for the cosmic censorship conjecture.Comment: 11 pages, 1 figure, Revtex

Collapse Dynamics of a Star of Dark Matter and Dark Energy

In this work, we study the collapse dynamics of an inhomogeneous spherically symmetric star made of dark matter (DM) and dark energy (DE). The dark matter is taken in the form of a dust cloud while anisotropic fluid is chosen as the candidate for dark energy. It is investigated how dark energy modifies the collapsing process and is examined whether dark energy has any effect on the Cosmic Censorship Conjecture. The collapsing star is assumed to be of finite radius and the space time is divided into three distinct regions $\Sigma$ and $V^{\pm}$, where $\Sigma$ represents the boundary of the star and $V^{-}(V^{+})$ denotes the interior (exterior) of the star. The junction conditions for matching $V^{\pm}$ over $\Sigma$ are specified. Role of Dark energy in the formation of apparent horizon is studied and central singularity is analyzed.Comment: 13 page

Evaluating bird communities of Western Ghats to plan for a biodiversity friendly development

Reconciling development with conservation of biological diversity has emerged as a significant concern in recent years. This has been primarily attempted through establishment of protected areas taken out of mainstream development, and through regulating impacts of major development projects with the help of environmental impact assessment exercises. We believe that these two instruments need to be complemented by continually providing inputs into the biodiversity implications of ongoing development processes (and accompanying habitat transformations) at the landscape and regional level. It is desirable that such assessment of biodiversity implications is based on a transparent, objective methodology which could be used by a wide range of practitioners working with the emerging decentralized processes of development planning. In this paper we outline such a methodology focussing on birds. This involves assigning a conservation value to bird species based on readily available information on their geographical range, habitat preference, endangerment and taxonomic distinctiveness. This may then be translated into a mean composite conservation value for bird assemblages characteristic of different habitat types. By combining this information with that on ongoing processes of habitat transformations, we can provide an assessment of how development processes are affecting biodiversity values. We illustrate this methodology by assessing the conservation value of 586 bird species of Western Ghats, and a sample of bird assemblages of seven major habitat types of the region. We conclude that the most serious loss of biodiversity value arises in the transformation of montane evergreen shola forests/high altitude grasslands into monoculture plantations