173 research outputs found
Stability Analyses of Earth Masses
During the past few months (January, 1966, to the present) the Division of Research has been called upon to make site investigations and analyses of foundation and slope stability at several locations in the State. These requests have emanated from various offices and divisions of the Department. Some of these investigations involved considerable effort and time to perform the subsurface exploration and to analyze the problem so that recommendations could be made. These investigations were of significant magnitude and are being summarized in this report
Some orangutans acquire enamel defects at regular intervals, but not according to seasonal cycles
Objectives: Developmental defects of tooth enamel are associated with systemic physiological stress and have been linked to seasonal environmental factors such as rainfall, temperature, and fruit availability. Here, we evaluate whether linear enamel hypoplasia and accentuated perikymata occur with any cyclicity on lower canines and then whether cycles differ between Bornean and Sumatran orangutans.
Materials and Methods: Epoxy casts of lower canines from Pongo abelii (n = 14) and P. pygmaeus (n = 33) were evaluated for perikymata and dental enamel defects. Individual developmental sequences (IDSs) were generated for each canine, tracking the position of each defect in the context of continuous perikymata (time). Autocorrelation, a form of timeâseries statistical analysis was run for each canine to identify whether any cyclicity of defect expression was discernable.
Results: Autocorrelation revealed cycles of defect expression within canines, but no common cycle periodicities were identified between individuals of the same species or across species. P. pygmaeus averaged more linear enamel hypoplasia per year than P. abelli, but no other comparisons (number of defects, number of perikymata between defects, and autocorrelation analysis) revealed differences between the species.
Discussion: Although no common patterns of defect expression were identified within or between P. abelli and P. pygmaeus, the potential for autocorrelation analysis is promising for primatological and paleoanthropological studies of seasonal phenomena
The wMelPop strain of Wolbachia interferes with dopamine levels in Aedes aegypti
Wolbachia is an intracellular bacterium that has been stably transinfected into the mosquito vector of dengue, Aedes aegypti. This inherited infection causes a range of metabolic and phenotypic alterations in the mosquito, which might be related to neuronal abnormalities. In order to determine if these alterations were caused by the manipulation of neuroamines by this bacterium, we studied the expression of genes involved in the dopamine biosynthetic pathway and also measured the amount of dopamine in infected and uninfected mosquitoes of different ages. Wolbachia-infected mosquitoes exhibit greater expression of some genes related to the melanization pathway, but not for those directly linked to dopamine production. Although dopamine levels were higher in Wolbachia-positive mosquitoes this was not consistent across all insect ages nor was it related to the previously described Wolbachia induced "bendy" and "shaky" phenotypes
Molar form, enamel growth, and durophagy in Cercocebus and Lophocebus
Objectives: To test the hypothesis that differences in crown structure, enamel
growth, and crown geometry in Cercocebus and Lophocebus molars covary with differences
in the feeding strategies (habitual vs. fallback durophagy, respectively) of these
two genera. Relative to Lophocebus molars, Cercocebus molars are predicted to possess
features associated with greater fracture resistance and to differ in enamel
growth parameters related to these features.
Materials and Methods: Sample proveniences are as follows: Cercocebus atys molars
are from the TaĂŻ Forest, Ivory Coast; Lophocebus albigena molars are from a site north
of Makoua, Republic of Congo; and a Lophocebus atterimus molar is from the Lomako
Forest, Democratic Republic of Congo. For ÎŒCT scans on which aspects of molar
form were measured, sample sizes ranged from 5 to 35 for Cercocebus and 3 to
12 for Lophocebus. A subsample of upper molars was physically sectioned to measure
enamel growth variables.
Results: Partly as a function of their larger size, Cercocebus molars had significantly
greater absolute crown strength (ACS) than Lophocebus molars, supporting the
hypothesis. Greater crown heights in Cercocebus are achieved through faster enamel
extension rates. Also supporting the hypothesis, molar flare and proportional occlusal
basin enamel thickness were significantly greater in Cercocebus. Relative enamel
thickness (RET), however, was significantly greater in Lophocebus.
Discussion: If ACS is a better predictor of fracture resistance than RET, then Cercocebus
molars may be more fracture resistant than those of Lophocebus. Greater molar
flare and proportional occlusal basin thickness might also afford Cercocebus molars
greater fracture resistance
Comparative susceptibility of mosquito populations in North Queensland, Australia to oral infection with dengue virus.
Dengue is the most prevalent arthropod-borne virus, with at least 40% of the world's population at risk of infection each year. In Australia, dengue is not endemic, but viremic travelers trigger outbreaks involving hundreds of cases. We compared the susceptibility of Aedes aegypti mosquitoes from two geographically isolated populations to two strains of dengue virus serotype 2. We found, interestingly, that mosquitoes from a city with no history of dengue were more susceptible to virus than mosquitoes from an outbreak-prone region, particularly with respect to one dengue strain. These findings suggest recent evolution of population-based differences in vector competence or different historical origins. Future genomic comparisons of these populations could reveal the genetic basis of vector competence and the relative role of selection and stochastic processes in shaping their differences. Lastly, we show the novel finding of a correlation between midgut dengue titer and titer in tissues colonized after dissemination
Hard plant tissues do not contribute meaningfully to dental microwear : evolutionary implications
Abstract: Reconstructing diet is critical to understanding hominin adaptations. Isotopic and functional morphological analyses of early hominins are compatible with consumption of hard foods, such as mechanically-protected seeds, but dental microwear analyses are not. The protective shells surrounding seeds are thought to induce complex enamel surface textures characterized by heavy pitting, but these are absent on the teeth of most early hominins. Here we report nanowear experiments showing that the hardest woody shells â the hardest tissues made by dicotyledonous plants â cause very minor damage to enamel but are themselves heavily abraded (worn) in the process. Thus, hard plant tissues do not regularly create pits on enamel surfaces despite high forces clearly being associated with their oral processing. We conclude that hard plant tissues barely inuence microwear textures and the exploitation of seeds from graminoid plants such as grasses and sedges could have formed a critical element in the dietary ecology of hominins
Persistent anthrax as a major driver of wildlife mortality in a tropical rainforest
Anthrax is a globally important animal disease and zoonosis. Despite this, our current knowledge of anthrax ecology is largely limited to arid ecosystems, where outbreaks are most commonly reported. Here we show that the dynamics of an anthrax-causing agent, Bacillus cereus biovar anthracis, in a tropical rainforest have severe consequences for local wildlife communities. Using data and samples collected over three decades, we show that rainforest anthrax is a persistent and widespread cause of death for a broad range of mammalian hosts. We predict that this pathogen will accelerate the decline and possibly result in the extirpation of local chimpanzee (Pan troglodytes verus) populations. We present the epidemiology of a cryptic pathogen and show that its presence has important implications for conservation
Parasite
Parasites and infectious diseases are well-known threats to primate populations. The main objective of this study was to provide baseline data on fecal parasites in the cercopithecid monkeys inhabiting CĂŽte d'Ivoire's TaĂŻ National Park. Seven of eight cercopithecid species present in the park were sampled: Cercopithecus diana, Cercopithecus campbelli, Cercopithecus petaurista, Procolobus badius, Procolobus verus, Colobus polykomos, and Cercocebus atys. We collected 3142 monkey stool samples between November 2009 and December 2010. Stool samples were processed by direct wet mount examination, formalin-ethyl acetate concentration, and MIF (merthiolate, iodine, formalin) concentration methods. Slides were examined under microscope and parasite identification was based on the morphology of cysts, eggs, and adult worms. A total of 23 species of parasites was recovered including 9 protozoa (Entamoeba coli, Entamoeba histolytica/dispar, Entamoeba hartmanni, Endolimax nana, Iodamoeba butschlii, Chilomastix mesnili, Giardia sp., Balantidium coli, and Blastocystis sp.), 13 nematodes (Oesophagostomum sp., Ancylostoma sp., Anatrichosoma sp., Capillariidae Gen. sp. 1, Capillariidae Gen. sp. 2, Chitwoodspirura sp., Subulura sp., spirurids [cf Protospirura muricola], Ternidens sp., Strongyloides sp., Trichostrongylus sp., and Trichuris sp.), and 1 trematode (Dicrocoelium sp.). Diversity indices and parasite richness were high for all monkey taxa, but C. diana, C. petaurista, C. atys, and C. campbelli exhibited a greater diversity of parasite species and a more equitable distribution. The parasitological data reported are the first available for these cercopithecid species within TaĂŻ National Park.
Les maladies parasitaires et infectieuses sont des menaces trĂšs connues pour les populations de primates. Lâobjectif principal de cette Ă©tude Ă©tait de fournir des donnĂ©es de base sur les parasites intestinaux des primates non-humains du Parc National de TaĂŻ en CĂŽte dâIvoire. Sept des huit espĂšces de cercopithĂ©cidĂ©s vivant dans le parc ont Ă©tĂ© Ă©chantillonnĂ©es : Cercopithecus diana, Cercopithecus campbelli, Cercopithecus petaurista, Procolobus badius, Procolobus verus, Colobus polykomos and Cercocebus atys. Nous avons collectĂ© 3142 Ă©chantillons de selles de singes de novembre 2009 Ă dĂ©cembre 2010. Les Ă©chantillons de selles ont Ă©tĂ© traitĂ©s par la technique dâexamen direct, les mĂ©thodes de concentration formol-Ă©thyl acĂ©tate et MIF (merthiolate, iode, formol). Les lames ont Ă©tĂ© examinĂ©es au microscope et lâidentification des parasites a Ă©tĂ© basĂ©e sur la morphologie des kystes, des Ćufs et des vers adultes. Au total, 23 espĂšces de parasites ont Ă©tĂ© trouvĂ©es, dont 9 protozoaires (Entamoeba coli, Entamoeba histolytica/dispar, Entamoeba hartmanni, Endolimax nana, Iodamoeba butschlii, Chilomastix mesnili, Giardia sp., Balantidium coli et Blastocystis sp.), 13 nĂ©matodes (Oesophagostomum sp., Ancylostoma sp., Anatrichosoma sp., Capillariidae Gen. sp. 1, Capillariidae Gen. sp. 2, Chitwoodspirura sp., Subulura sp., Spiruridae [cf. Protospirura muricola], Ternidens sp., Strongyloides sp., Trichostrongylus sp. et Trichuris sp.), et un trĂ©matode (Dicrocoelium sp.). Lâindice de diversitĂ© et la richesse parasitaire Ă©taient Ă©levĂ©s pour tous les taxa de singes, mais C. diana, C. petaurista, C. atys and C. campbelli ont enregistrĂ© une plus grande diversitĂ© et une distribution plus Ă©quitable des espĂšces de parasites. Les donnĂ©es parasitologiques que nous rapportons sont les premiĂšres disponibles pour ces espĂšces de singes du Parc National de TaĂŻ
Human Probing Behavior of Aedes aegypti when Infected with a Life-Shortening Strain of Wolbachia
Mosquitoes transmit diseases when they are actively searching for a source of blood. This so called probing behavior comprises the âsearchingâ time, the beginning of the feeding process until the first sign of blood can be seen within the insect body. The manipulation of this behavior can have important consequences for the mosquito's ability to transmit pathogens, such as dengue virus or Plasmodium. In this study we examined the probing behavior of the main vector of dengue viruses, Aedes aegypti, when infected with an intracellular bacterium, Wolbachia pipientis. This bacterium alters the probing behavior of older mosquitoes such that they take longer to find a feeding site and longer to imbibe blood, which may make them more susceptible to human defense responses. The bacterium appears to reduce mosquito feeding success by preventing the mosquito from successfully inserting its stylet into human skin. The old age onset of reduced mosquito feeding success due to Wolbachia could selectively promote a reduction in dengue transmission
Hard-Object Feeding in Sooty Mangabeys (Cercocebus atys) and Interpretation of Early Hominin Feeding Ecology
Morphology of the dentofacial complex of early hominins has figured prominently in the inference of their dietary adaptations. Recent theoretical analysis of craniofacial morphology of Australopithecus africanus proposes that skull form in this taxon represents adaptation to feeding on large, hard objects. A modern analog for this specific dietary specialization is provided by the West African sooty mangabey, Cercocebus atys. This species habitually feeds on the large, exceptionally hard nuts of Sacoglottis gabonensis, stereotypically crushing the seed casings using their premolars and molars. This type of behavior has been inferred for A. africanus based on mathematical stress analysis and aspects of dental wear and morphology. While postcanine megadontia, premolar enlargement and thick molar enamel characterize both A. africanus and C. atys, these features are not universally associated with durophagy among living anthropoids. Occlusal microwear analysis reveals complex microwear textures in C. atys unlike those observed in A. africanus, but more closely resembling textures observed in Paranthropus robustus. Since sooty mangabeys process hard objects in a manner similar to that proposed for A. africanus, yet do so without the craniofacial buttressing characteristic of this hominin, it follows that derived features of the australopith skull are sufficient but not necessary for the consumption of large, hard objects. The adaptive significance of australopith craniofacial morphology may instead be related to the toughness, rather than the hardness, of ingested foods
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