138 research outputs found
Investigating the Relationship between Algae-Feeding Fish Populations and Coral Cover and Diversity in Roatan, Honduras
On the strength of the finite intersection principle
We study the logical content of several maximality principles related to the
finite intersection principle (F\IP) in set theory. Classically, these are
all equivalent to the axiom of choice, but in the context of reverse
mathematics their strengths vary: some are equivalent to \ACA over \RCA,
while others are strictly weaker, and incomparable with \WKL. We show that
there is a computable instance of F\IP all of whose solutions have
hyperimmune degree, and that every computable instance has a solution in every
nonzero c.e.\ degree. In terms of other weak principles previously studied in
the literature, the former result translates to F\IP implying the omitting
partial types principle (). We also show that, modulo
induction, F\IP lies strictly below the atomic model theorem
().Comment: This paper corresponds to section 3 of arXiv:1009.3242, "Reverse
mathematics and equivalents of the axiom of choice", which has been
abbreviated and divided into two pieces for publicatio
Hyaluronidase of Bloodsucking Insects and Its Enhancing Effect on Leishmania Infection in Mice
Hyaluronidases are enzymes degrading the extracellular matrix of vertebrates. Bloodsucking insects use them to cleave the skin of the host, enlarge the feeding lesion and acquire the blood meal. In addition, resulting fragments of extracellular matrix modulate local immune response of the host, which may positively affect transmission of vector-borne diseases, including leishmaniasis. Leishmaniases are diseases with a wide spectrum of clinical forms, from a relatively mild cutaneous affection to life-threatening visceral disease. Their causative agents, protozoans of the genus Leishmania, are transmitted by phlebotomine sand flies. Sand fly saliva was described to enhance Leishmania infection, but the information about molecules responsible for this exacerbating effect is still very limited. In the present work we demonstrated hyaluronidase activity in salivary glands of various Diptera and in fleas. In addition, we showed that hyaluronidase exacerbates Leishmania lesions in mice and propose that salivary hyaluronidase may facilitate the spread of other vector-borne microorganisms
Mycobacteria Exploit Host Hyaluronan for Efficient Extracellular Replication
In spite of the importance of hyaluronan in host protection against infectious organisms in the alveolar spaces, its role in mycobacterial infection is unknown. In a previous study, we found that mycobacteria interact with hyaluronan on lung epithelial cells. Here, we have analyzed the role of hyaluronan after mycobacterial infection was established and found that pathogenic mycobacteria can grow by utilizing hyaluronan as a carbon source. Both mouse and human possess 3 kinds of hyaluronan synthases (HAS), designated HAS1, HAS2, and HAS3. Utilizing individual HAS-transfected cells, we show that HAS1 and HAS3 but not HAS2 support growth of mycobacteria. We found that the major hyaluronan synthase expressed in the lung is HAS1, and that its expression was increased after infection with Mycobacterium tuberculosis. Histochemical analysis demonstrated that hyaluronan profoundly accumulated in the granulomatous legion of the lungs in M. tuberculosis-infected mice and rhesus monkeys that died from tuberculosis. We detected hyaluronidase activity in the lysate of mycobacteria and showed that it was critical for hyaluronan-dependent extracellular growth. Finally, we showed that L-Ascorbic acid 6-hexadecanoate, a hyaluronidase inhibitor, suppressed growth of mycobacteria in vivo. Taken together, our data show that pathogenic mycobacteria exploit an intrinsic host-protective molecule, hyaluronan, to grow in the respiratory tract and demonstrate the potential usefulness of hyaluronidase inhibitors against mycobacterial diseases
Lyapunov spectrum of asymptotically sub-additive potentials
For general asymptotically sub-additive potentials (resp. asymptotically
additive potentials) on general topological dynamical systems, we establish
some variational relations between the topological entropy of the level sets of
Lyapunov exponents, measure-theoretic entropies and topological pressures in
this general situation. Most of our results are obtained without the assumption
of the existence of unique equilibrium measures or the differentiability of
pressure functions. Some examples are constructed to illustrate the
irregularity and the complexity of multifractal behaviors in the sub-additive
case and in the case that the entropy map that is not upper-semi continuous.Comment: 44 page
Past and future corollaries of theories on causes of metabolic syndrome and obesity related co-morbidities part 2: a composite unifying theory review of human-specific co-adaptations to brain energy consumption
Analyzing Chaotic Motion in a Computational Double Pendulum
This project explores the principles of chaos through the motion of a double pendulum. The motion of the double pendulum is estimated by numerically integrating its Euler-Lagrange equations of motion using numerical integration methods. The motion is simulated using Python and PyGame. The model allows the users to visually observe sensitivity to initial conditions, a defining characteristic of chaotic motion. The conditions which produce chaos in the double pendulum are investigated using quantitative and qualitative measures of chaos. The results illustrate the chaotic nature of the double pendulum and the qualitative results support the use of the Lyapunov exponent as a quantitative measure of chaos
Investigating the Relationship Between Algae-Feeding Fish Populations and Coral Cover and Diversity in Roatan, Honduras
The relationship between algae-feeding fish populations and coral health should be further investigated to gain a better understanding of the complex ecosystems of coral reefs. If the complex ecosystems of coral reefs are better understood, more successful conservation efforts can be implemented. A description and brief history of the proposed research site will be provided. In addition, past research that influenced the development of the proposal will be summarized. Lastly, the methodology of the proposed research will be detailed and a prediction of possible outcomes will be given
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Phacelia minor (Harvey) Thell.California bluebell, Wild canterbury bells1/2 mile in San Bernardino National Forest, 7 miles SE of Banningin chapparal; found in sun4500 feetcommonannual 6 dm. tall with purple flower
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