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PubMed1999

Uniformity of colour vision in Old World monkeys.

It is often assumed that all Old World monkeys share the same trichromatic colour vision, but the evidence in support of this conclusion is sparse as only a small fraction of all Old World monkey species have been tested. To address this issue, spectral sensitivity functions were measured in animals from eight species of Old World monkey (five cercopithecine species and three colobine species) using a non-invasive electrophysiological technique. Each of the 25 animals examined had spectrally well-separated middle- and long-wavelength cone pigments. Cone pigments maximally sensitive to short wavelengths were also detected, implying the presence of trichromatic colour vision. Direct comparisons of the spectral sensitivity functions of Old World monkeys suggest there are no significant variations in the spectral positions of the cone pigments underlying the trichromatic colour vision of Old World monkeys.

Animals↗
PubMed1995

Evolutionary history of New and Old World vultures inferred from nucleotide sequences of the mitochondrial cytochrome b gene.

The phylogeny of 11 species of Old World vultures (Aves: Accipitriformes, Aegypiinae), three species of New World vultures (Cathartidae) and theri nearest relatives within and outside the order Accipitriformes was investigated based on 1026 nucleotides of the mitochondrial cytochrome b gene. The data support the contention that New World vultures are not birds of prey, but phylogenetic information was insufficient to identify whether they are closer to storks (Ciconiidae) or to Accipitriformes. Four species of Gyps are all closely related and probably speciated within the Pleistocene. Molecular data do not support the split of 'white-backed' vultures from Gyps in a separate genus Pseudogyps. The monotypic genera of large, heavy-billed vultures, Aegypius, Torgos, Trigonoceps and Sarcogyps, are of monophyletic origin. We propose to merge Torgos with Aegypius, but retain Trigonoceps and Sarcogyps as separate genera, Sarcogyps being clearly the most primitive of the four. All four, together with Gyps and Necrosyrtes, form a monophyletic subfamily or 'core group', to which the subfamily Aegypiinae should be restricted. This group shares a more recent common ancestor with several non-vulture genera of Accipitrids, among them Buteo, Aquila, Haliaeetus and Circaetus, than it does with the two aberrent vultures Gypaetus barbatus and Neophron percnopterus. The last two are much more primitive; they seem to be each other's sister species and are closer to Pernis than to other Accipitrids. We propose separating Gypaetus and Neophron in the subfamily Gypaetinae. If the cytochrome b gene tree accurately reflects vulture phylogeny, Old World vultures are polyphyletic with the Aegypius-Gyps clade having evolved convergently to the more ancient Gypaetus and Neophron vultures. Polyphyly of Old World vultures, although in conflict with the DNA-DNA hybridization phylogeny of Sibley & Ahlquist (1990), is well supported by molecular, karyotypic, morphological and other phenotypic evidence (behaviour, voice) indicating fundamental differences between the two evolutionary lines.

Americas↗
PubMed2001

Small worlds: how and why.

We investigate small-world networks from the point of view of their origin. While the characteristics of small-world networks are now fairly well understood, there is as yet no work on what drives the emergence of such a network architecture. In situations such as neural or transportation networks, where a physical distance between the nodes of the network exists, we study whether the small-world topology arises as a consequence of a tradeoff between maximal connectivity and minimal wiring. Using simulated annealing, we study the properties of a randomly rewired network as the relative tradeoff between wiring and connectivity is varied. When the network seeks to minimize wiring, a regular graph results. At the other extreme, when connectivity is maximized, a "random" network is obtained. In the intermediate regime, a small-world network is formed. However, unlike the model of Watts and Strogatz [Nature 393, 440 (1998)], we find an alternate route to small-world behavior through the formation of hubs, small clusters where one vertex is connected to a large number of neighbors.

Algorithms↗
PubMed2006

Hybrid graphs as a framework for the small-world effect.

In this paper we formalize the small-world effect which describes the surprising fact that a hybrid graph composed of a local graph component and a very sparse random graph has a diameter of O(ln n) whereby the diameter of both components alone is much higher. We show that a large family of these hybrid graphs shows this effect and that this generalized family also includes classic small-world models proposed by various authors although not all of them are captured by the small-world definition given by Watts and Strogatz. Furthermore, we give a detailed upper bound of the hybrid's graph diameter for different choices of the expected number of random edges by applying a new kind of proof pattern that is applicable to a large number of hybrid graphs. The focus in this paper is on presenting a flexible family of hybrid graphs showing the small-world effect that can be tuned closely to real-world systems.

Journal Article↗
PubMed2006

Inverted Berezinskii-Kosterlitz-Thouless singularity and high-temperature algebraic order in an Ising model on a scale-free hierarchical-lattice small-world network.

We have obtained exact results for the Ising model on a hierarchical lattice incorporating three key features characterizing many real-world networks--a scale-free degree distribution, a high clustering coefficient, and the small-world effect. By varying the probability p of long-range bonds, the entire spectrum from an unclustered, non-small-world network to a highly clustered, small-world system is studied. Using the self-similar structure of the network, we obtain analytic expressions for the degree distribution P(k) and clustering coefficient C for all p, as well as the average path length l for p = 0 and 1. The ferromagnetic Ising model on this network is studied through an exact renormalization-group transformation of the quenched bond probability distribution, using up to 562,500 renormalized probability bins to represent the distribution. For p < 0.494, we find power-law critical behavior of the magnetization and susceptibility, with critical exponents continuously varying with p, and exponential decay of correlations away from Tc. For p > or = 0.494, in fact where the network exhibits small-world character, the critical behavior radically changes: We find a highly unusual phase transition, namely an inverted Berezinskii-Kosterlitz-Thouless singularity, between a low-temperature phase with nonzero magnetization and finite correlation length and a high-temperature phase with zero magnetization and infinite correlation length, with power-law decay of correlations throughout the phase. Approaching Tc from below, the magnetization and the susceptibility, respectively, exhibit the singularities of exp(-C/square root of Tc - T) and exp(D/square root of Tc - T), with C and D positive constants. With long-range bond strengths decaying with distance, we see a phase transition with power-law critical singularities for all p, and evaluate an unusually narrow critical region and important corrections to power-law behavior that depend on the exponent characterizing the decay of long-range interactions.

Journal Article↗
PubMed2003

Two spheres of belief in justice: extensive support for the bidimensional model of belief in a just world.

The purpose of this research comprising five studies (N = 666) was to further corroborate the bidimensional conceptualisation of the belief in a just world proposed by Lipkus et al. (1996). It was demonstrated that belief in a just world for the Self (and not for Others) was correlated to evaluations of the meaning of life. Belief in a just world for Others was significantly correlated to discrimination against the elderly, stigmatisation of poverty, and higher penal punitiveness, while belief in a just world for Self was weakly or not related to these variables. Together, these observations confirm the importance of the conceptual and psychometric distinction between these two spheres of the belief in a just world.

Adolescent↗
PubMed2004

Product delivery in the developing world: options, opportunities and threats.

While many developed countries are moving to recombinant coagulation factors as their preferred modality for delivering haemophilia care, the cost of these products currently impedes their access by developing countries. A number of options are available to these countries for the provision of plasma-derived therapeutic products. The decreasing market for plasma-derived coagulation factors in the developed world is leading to the generation of a surplus of these products and an ability to offer them outside their traditional markets if prices are affordable. Current indications are that the commercial fractionation industry of the developed world has an excess capacity in both available plasma and fractionation plants. It would seem that accessing this capacity might have attractions for the developing world. Countries wedded to achieving self-sufficiency in haemophilia products may elect to develop a strategy for fractionating domestically sourced plasma. This may be achieved by the generation of a capacity to fractionate within the country or by contracting the fractionation to an external agency overseas. However, reliance on domestic plasma should not be allowed to impede access to sufficient and safe coagulation products. Irrespective of the route chosen, products need to attain satisfactory compliance to standards for safety, quality and efficacy. This is best done through alignment of the products with the requirements of credible regulatory agencies. While the approval of the mainstream regulators of the developed world affords considerable assurance regarding product quality, the increasing efforts made by fractionation agencies in the developing world to attain best practice is commendable and augurs well for the enhancement of haemophilia care in these countries.

Blood Coagulation Factors↗
PubMed1997

Fine structure of gene frequency landscapes in domestic cat: the Old and New Worlds compared.

The dependence of variance of coat gene frequencies on geographic distance was studied in stray domestic cat populations by means of analysis of variance (ANOVA) and variance ratio test (F-test) with the data set containing 333 samples. The procedure included the stepwise estimation of variances within square pieces of territory of gradually increasing size performed separately for the Old and New Worlds. It is revealed that beginning with 200-300 km-size of square side, for the most loci studied, these distance-controlled variances are significantly less in the New World, thus indicating a smoother gene frequency landscape. In both worlds, the tb and t alleles show significantly higher variances than the other mutant alleles. The mean allele frequencies in the New World are significantly higher than in the western European area, from where colonization took place for alleles that constitute a "luxury" gene group (O, d, l, W) presumably formed by human preference. The results support in general the historical/immigration hypothesis, i.e., that domestic cat colonization of the New World proceeded by rapid population expansion without a great gene frequency change (bottleneck-like effect). A modification is suggested for the model: a biased colonization sample (a founder effect) in regards to O, d, l, and W alleles.

Africa↗
PubMed2005

Reduced prevalence of Epstein-Barr virus-related lymphocryptovirus infection in sera from a new world primate.

The recent discovery of an Epstein-Barr virus (EBV)-related lymphocryptovirus (LCV) naturally infecting common marmosets demonstrated that gamma-1 herpesviruses are not limited to human and Old World nonhuman primate hosts. We developed serologic assays to detect serum antibodies against lytic- and latent-infection marmoset LCV antigens in order to perform the first seroepidemiologic study of LCV infection in New World primates. In three different domestic colonies and in animals recently captured from the wild, we found that the seroprevalence of marmoset LCV infection was not as ubiquitous as with EBV or Old World LCV. These biologic differences in LCV infection of New World versus human and Old World primate hosts correlate with the evolution of the LCV viral gene repertoire.

Amino Acid Sequence↗
PubMed2003

Collecting behavioural data using the world wide web: considerations for researchers.

OBJECTIVE: To identify and describe advantages, challenges, and ethical considerations of web based behavioural data collection. METHODS: This discussion is based on the authors' experiences in survey development and study design, respondent recruitment, and internet research, and on the experiences of others as found in the literature. RESULTS: The advantages of using the world wide web to collect behavioural data include rapid access to numerous potential respondents and previously hidden populations, respondent openness and full participation, opportunities for student research, and reduced research costs. Challenges identified include issues related to sampling and sample representativeness, competition for the attention of respondents, and potential limitations resulting from the much cited "digital divide", literacy, and disability. Ethical considerations include anonymity and privacy, providing and substantiating informed consent, and potential risks of malfeasance. CONCLUSIONS: Computer mediated communications, including electronic mail, the world wide web, and interactive programs will play an ever increasing part in the future of behavioural science research. Justifiable concerns regarding the use of the world wide web in research exist, but as access to, and use of, the internet becomes more widely and representatively distributed globally, the world wide web will become more applicable. In fact, the world wide web may be the only research tool able to reach some previously hidden population subgroups. Furthermore, many of the criticisms of online data collection are common to other survey research methodologies.

Behavioral Research↗
PubMed1989

'Delusion of world destruction' (Wetzel). Comparative study between Japan and West Germany.

It has been said that the delusion of world destruction (Weltuntergangserlebnis) in schizophrenia is closely related to Christian culture, and is less frequent in Oriental than in Western countries. Schizophrenic inpatients with delusions of world destruction treated at the Universitäts-Nervenklinik, Tübingen, FRG, were compared with corresponding inpatients at Keio University Hospital and allied hospitals in Japan. As a result, in West Germany, there were 7 (4.7%) patients with delusions of world destruction among 150 schizophrenic patients, accounting for 5.3% of all 131 patients with some delusion. In Japan, 5 (2.8%) of 178 schizophrenic patients had such delusions, accounting for 3.0% of all 166 patients with some delusion. There was no statistically significant difference between the two countries. These incidences were similar to those reported by Kranz (5, 3 and 8% in 1886, 1916 and 1946, respectively) and by Huber and Gross (5.8%). Accordingly, it seems that, although the delusion of world destruction, as a form of world catastrophe, is rare, it occurs among schizophrenic patients at a rather constant incidence, irrespective of the culture or area.

Adult↗
PubMedDate not supplied

Community monitoring of integrated pest management versus conventional pesticide use in a World Bank project in Indonesia.

Pesticide Action Network North America (PANNA) collaborated with a local Indonesian nongovernmental organization (NGO), Yayasan Duta Awam (YDA), in monitoring impacts of the World Bank-financed Integrated Swamps Development Project (ISDP). This paper reports the results of the community-based investigation, which found wide disparities between the World Bank's policy on pest management and its implementation. Instead of reducing farmers' reliance on pesticides as required, the ISDP led to increased intensity and frequency of pesticide use and adverse health and environmental effects from pesticide exposures. YDA and PANNA presented the findings to the Indonesian government and World Bank officials, and farmers requested training in IPM among other recommendations. After NGOs undertook joint advocacy efforts to reduce pesticide dependence in the project, the World Bank withdrew hazardous pesticides from input packages, IPM training was initiated, and community monitors became local leaders in their villages. The study demonstrates the importance and efficacy of independent community-based monitoring in documenting pesticide problems and replacing pesticides with IPM in World Bank development projects.

Agriculture↗
PubMed2006

The ancient Virus World and evolution of cells.

BACKGROUND: Recent advances in genomics of viruses and cellular life forms have greatly stimulated interest in the origins and evolution of viruses and, for the first time, offer an opportunity for a data-driven exploration of the deepest roots of viruses. Here we briefly review the current views of virus evolution and propose a new, coherent scenario that appears to be best compatible with comparative-genomic data and is naturally linked to models of cellular evolution that, from independent considerations, seem to be the most parsimonious among the existing ones. RESULTS: Several genes coding for key proteins involved in viral replication and morphogenesis as well as the major capsid protein of icosahedral virions are shared by many groups of RNA and DNA viruses but are missing in cellular life forms. On the basis of this key observation and the data on extensive genetic exchange between diverse viruses, we propose the concept of the ancient virus world. The virus world is construed as a distinct contingent of viral genes that continuously retained its identity throughout the entire history of life. Under this concept, the principal lineages of viruses and related selfish agents emerged from the primordial pool of primitive genetic elements, the ancestors of both cellular and viral genes. Thus, notwithstanding the numerous gene exchanges and acquisitions attributed to later stages of evolution, most, if not all, modern viruses and other selfish agents are inferred to descend from elements that belonged to the primordial genetic pool. In this pool, RNA viruses would evolve first, followed by retroid elements, and DNA viruses. The Virus World concept is predicated on a model of early evolution whereby emergence of substantial genetic diversity antedates the advent of full-fledged cells, allowing for extensive gene mixing at this early stage of evolution. We outline a scenario of the origin of the main classes of viruses in conjunction with a specific model of precellular evolution under which the primordial gene pool dwelled in a network of inorganic compartments. Somewhat paradoxically, under this scenario, we surmise that selfish genetic elements ancestral to viruses evolved prior to typical cells, to become intracellular parasites once bacteria and archaea arrived at the scene. Selection against excessively aggressive parasites that would kill off the host ensembles of genetic elements would lead to early evolution of temperate virus-like agents and primitive defense mechanisms, possibly, based on the RNA interference principle. The emergence of the eukaryotic cell is construed as the second melting pot of virus evolution from which the major groups of eukaryotic viruses originated as a result of extensive recombination of genes from various bacteriophages, archaeal viruses, plasmids, and the evolving eukaryotic genomes. Again, this vision is predicated on a specific model of the emergence of eukaryotic cell under which archaeo-bacterial symbiosis was the starting point of eukaryogenesis, a scenario that appears to be best compatible with the data. CONCLUSION: The existence of several genes that are central to virus replication and structure, are shared by a broad variety of viruses but are missing from cellular genomes (virus hallmark genes) suggests the model of an ancient virus world, a flow of virus-specific genes that went uninterrupted from the precellular stage of life's evolution to this day. This concept is tightly linked to two key conjectures on evolution of cells: existence of a complex, precellular, compartmentalized but extensively mixing and recombining pool of genes, and origin of the eukaryotic cell by archaeo-bacterial fusion. The virus world concept and these models of major transitions in the evolution of cells provide complementary pieces of an emerging coherent picture of life's history. REVIEWERS: W. Ford Doolittle, J. Peter Gogarten, and Arcady Mushegian.

Journal Article↗
PubMed2003

Phylogeny of the lizard subfamily Lygosominae (Reptilia: Scincidae), with special reference to the origin of the new world taxa.

Phylogenetic relationships of the three lygosomine skink genera occurring both in the Old World and the New World (Mabuya, Scincella and Sphenomorphus) were inferred from mitochondrial DNA sequence of 12S and 16S rRNA genes. Results strongly suggested the non-monophyly for any of these three genera. Within the Mabuya group, Asian members appear to have diverged first, leaving the Neotropical and the Afro-Malagasy Mabuya as sister groups. These relationships, together with the absence of extant or fossil representatives of the Mabuya group from North America, strongly suggest the trans-Atlantic dispersals of Mabuya from Africa to Neotropics. Our results also indicated a closer affinity of the New World Scincella with the New World Sphenomorphus than with the Old World Scincella. Such relationships suggest the trans-Beringian dispersal of the common ancestor from Asia and its subsequent divergence into the North American Scincella and the Neotropical Sphenomorphus.

Animals↗
PubMed2003

What can consumer adverse drug reaction reporting add to existing health professional-based systems? Focus on the developing world.

The current system of pharmacovigilance encourages reporting of adverse drug reactions (ADRs) mainly from healthcare professionals. Underreporting is a major problem, more so in the developing world than in the developed world. Less than 3% of reports added to the WHO database in the year 2000 originated from developing countries, although around 80% of the global population lives in the developing world [corrected]. Also a considerable time lag still exists in recognition of serious ADRs. Hence, there is a need for a different approach to pharmacovigilance. We present an overview of possible reasons for underreporting by healthcare professionals with particular emphasis on the developing world, and the potential benefits of encouraging consumer reporting. Only a few countries accept consumer reports. We suggest an independent consumer reporting system for hypothesis generation to complement the present health professional-based system. We also highlight the low priority given by multinational pharmaceutical companies to the developing countries regarding new safety information. The important questions are whether the resources available would be sufficiently robust to sustain such a system in the developing world, and whether it will be sufficiently robust and sensitive for the early detection of signals.

Adverse Drug Reaction Reporting Systems↗
PubMed1981

The deterioration of the food situation in the Third World and the capitalist system.

Hunger and malnutrition are today associated with the capitalist system. The evidence points to a further deterioration of the food situation in the Third World in the foreseeable future, as a result of massive capital and technology transfers from the rich capitalist countries to the underdeveloped agricultures operated by trans-national concerns or private investors, with the active support of development assistance agencies such as the World Bank. Contrary to the superficial predictions of the World Bank, for example, poverty is bound to increase and the purchasing power of the masses must decline. Particular attention must be paid to the supply of staple foods and the proletariat. This is threatened by a variety of factors, attributable to the operation of the capitalist system. Among them are the senseless waste of Third World resources caused by the foreign investors' insatiable thirst for the quick repatriation of super-profits and the increasing orientation of Third World agricultures toward high-value or export crops (which are usually the same), an orientation which is imposed upon them by the industrial countries' agricultural development strategies. Even self-sufficiency programs for more staple foods, such as the ill-reputed Green Revolution, predictably cannot be of long duration.

Agriculture↗
PubMed1988

Just World beliefs and attitudes toward helping elderly people: a comparison of British and Canadian university students.

Social science students from a British university and a Canadian university were studied to determine the relationship between their beliefs in a just world and their attitudes toward helping elderly people who have social, economic or health needs. Approximately 30 percent of the British students (N = 71) and 50 percent of the Canadian students (N = 124) expressed a belief in a just world. In both groups, just world believers blamed elderly people for being in poor health or financial circumstances, and the Canadian just world believers also tended to dismiss the needs of elderly people for the convenience of society. These and other differences in the attitudes of the British and Canadian students toward elderly people are discussed from a social and historical context. Implications of a belief in a just world by social science students are discussed in relation to the provision of social services to elderly people.

Adolescent↗
PubMed2004

Using "Bud World Party" attendance to predict adolescent alcohol use and beliefs about drinking.

This study explored the association between attendance at the "Bud World Party," a family entertainment venue created by Anheuser-Busch for the 2002 Winter Olympics, and alcohol-related beliefs and current drinking behaviors for a group of 7th and 8th graders who attend a middle school in close proximity to the downtown Salt Lake City plaza where the exhibit and related events were located. Data were collected via a questionnaire administered to 283 students 30 days after the closing ceremonies.. Logistic regression was used to predict recent alcohol consumption. Significant predictors were race (non-white) (OR = 3.9), religiosity (OR = .72), having a parent who drinks (OR = 4.8), the number of best friends who drink (OR = 2.5), and the interaction for "Bud World Party" attendance and gender (OR = 33.2). Post-hoc analysis of the interaction effect indicated that the relationship between "Bud World Party" attendance and recent alcohol consumption is moderated by gender. Girls who visited "Bud World Party" were more likely than the boys to have consumed alcohol in the past 30 days. In addition, the girls who visited "Bud World Party" were more likely to believe that drinking would increase their chances of popularity at school than the students who did not.

Adolescent↗