Polynomial and linearized normal forms for almost periodic differential systems

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Multiplicity of limit cycles and analytic m-solutions for planar differential systems

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Dynamics of the third order Lyness' difference equation

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Dysproteinaemia in the differential diagnosis of kala-azar

Serum protein abnormalities were examined in six kala-azar (KA) patients, six controls with positive immunofluorescence tests with Leishmania donovani antigens, and six seronegative controls. KA patients were clearly distinguishable from controls by several parameters, including A/G ratio, albumin and globulin levels, IgM and IgG titers, and positive rheumatoid factor (RF) tests. A positive relationship was noted between RF titers and serum levels of IgM. The diagnostic value and possibel pathologic significance of serum abnormalities in KA is discussed.

On the existence and uniqueness of limit cycles in Liénard differential equations allowing discontinuities

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The equation xpyq=zr and groups that act freely on Λ-trees

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Differential effect of culture epimastigotes and blood-form Trypamastigotes on normal mouse splenocyte responsiveness to mitogens

Blood form trypomastigotes of the Y strain of T. cruzi, produced a strong inhibition of the blastogenic response to T and B cell mitogens, of the C3H/He, C57BLand BALB/cJ strains of mice, while culture epimastigotes of the Y strain kept in a medium that allows parasite growth at 26°. 30° and 37°C produced a strong stimulatory effect that was even higher than the effect of the mitogens alone. Both the inhibitory or the stimulatory effects were dose-dependent. The stimulatory effect of epimastigotes was also temperature-dependent producing increasedstimulation indexes as the temperature of parasite cultures was raised. Metabolically active,living parasites seemed to be necessary for an improved lymphocyte stimulation suggesting a potential role of secreted metabolites as polyclonal activators of mouse lymphocytes.

Differential effects of two anti-apo-cytochrome c-specific monoclonal antibodies on the function of apo-cytochrome c-specific murine T cell clones.

A murine monoclonal antibody (SJL 2-4) specific for the antigen apo-cytochrome c was shown to inhibit both antigen-induced proliferation and lymphokine secretion by an apo-cytochrome c-specific BALB/c helper T cell clone. The inhibition was specific because additional apo-cytochrome c-specific T cell clones were not inhibited by the same monoclonal antibody. Time course studies of the inhibition indicated that the initial 8 hr of contact between T cell clones and antigen-presenting cells were critical for activation of the T cell clones. Inhibition of T cell functions by antigen-specific antibodies appeared to correlate with the antibody-antigen binding constant because a second monoclonal antibody (Cyt-1-59), with identical specificity but with a lower affinity constant for apo-cytochrome c, had very little inhibitory effect on the proliferation or lymphokine secretion of apo-cytochrome c-specific T cell clones.

A curious example of two model categories and some associated differential graded algebras

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Hopf bifurcation in higher dimensional differential systems via the averaging method

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Differential effect of long versus short wavelength light exposure on pupillary re-dilation in patients with outer retinal disease.

BACKGROUND: In patients with outer retinal degeneration, a differential pupil response to long wavelength (red) versus short wavelength (blue) light stimulation has been previously observed. The goal of this study was to quantify differences in the pupillary re-dilation following exposure to red versus blue light in patients with outer retinal disease and compare them with patients with optic neuropathy and with healthy subjects. DESIGN: Prospective comparative cohort study. PARTICIPANTS: Twenty-three patients with outer retinal disease, 13 patients with optic neuropathy and 14 normal subjects. METHODS: Subjects were tested using continuous red and blue light stimulation at three intensities (1, 10 and 100 cd/m2) for 13 s per intensity. Pupillary re-dilation dynamics following the brightest intensity was analysed and compared between the three groups. MAIN OUTCOME MEASURES: The parameters of pupil re-dilation used in this study were: time to recover 90% of baseline size; mean pupil size at early and late phases of re-dilation; and differential re-dilation time for blue versus red light. RESULTS: Patients with outer retinal disease showed a pupil that tended to stay smaller after light termination and thus had a longer time to recovery. The differential re-dilation time was significantly greater in patients with outer retinal disease (median = 28.0 s, P < 0.0001) compared with controls and patients with optic neuropathy. CONCLUSIONS: A differential response of pupil re-dilation following red versus blue light stimulation is present in patients with outer retinal disease but is not found in normal eyes or among patients with visual loss from optic neuropathy.

Differential regulations of AQP4 and Kir4.1 by triamcinolone acetonide and dexamethasone in the healthy and inflamed retina.

PURPOSE: Glucocorticoids are used to treat macular edema, although the mechanisms underlying this effect remain largely unknown. The authors have evaluated in the normal and endotoxin-induced uveitis (EIU) rats, the effects of dexamethasone (dex) and triamcinolone acetonide (TA) on potassium channel Kir4.1 and aquaporin-4 (AQP4), the two main retinal Müller glial (RMG) channels controlling retinal fluid movement. METHODS: Clinical as well as relatively low doses of dex and TA were injected in the vitreous of normal rats to evaluate their influence on Kir4.1 and AQP4 expression 24 hours later. The dose-dependent effects of the two glucocorticoids were investigated using rat neuroretinal organotypic cultures. EIU was induced by footpad lipopolysaccharide injection, without or with 100 nM intraocular dex or TA. Glucocorticoid receptor and channel expression levels were measured by quantitative PCR, Western blot, and immunohistochemistry. RESULTS: The authors found that dex and TA exert distinct and specific channel regulations at 24 hours after intravitreous injection. Dex selectively upregulated Kir4.1 (not AQP4) in healthy and inflamed retinas, whereas TA induced AQP4 (not Kir4.1) downregulation in normal retina and upregulation in EIU. The lower concentration (100 nM) efficiently regulated the channels. Moreover, in EIU, an inflammatory condition, the glucocorticoid receptor was downregulated in the retina, which was prevented by intravitreous injections of the low concentration of dex or TA. CONCLUSIONS: The results show that dex and TA are far from being equivalent to modulate RMG channels. Furthermore, the authors suggest that low doses of glucocorticoids may have antiedematous effects on the retina with reduced toxicity.

Chebyshev polynomial approximation to approximate partial differential equations

This paper suggests a simple method based on Chebyshev approximation at Chebyshev nodes to approximate partial differential equations. The methodology simply consists in determining the value function by using a set of nodes and basis functions. We provide two examples. Pricing an European option and determining the best policy for chatting down a machinery. The suggested method is flexible, easy to program and efficient. It is also applicable in other fields, providing efficient solutions to complex systems of partial differential equations.

Analysing the impact of public capital stock using the NEG wage equation: a panel data approach

This paper examines the relationship between the level of public infrastructure and the level of productivity using panel data for the Spanish provinces over the period 1984-2004, a period which is particularly relevant due to the substantial changes occurring in the Spanish economy at that time. The underlying model used for the data analysis is based on the wage equation, which is one of a handful of simultaneous equations which when satisfied correspond to the short-run equilibrium of New Economic Geography theory. This is estimated using a spatial panel model with fixed time and province effects, so that unmodelled space and time constant sources of heterogeneity are eliminated. The model assumes that productivity depends on the level of educational attainment and the public capital stock endowment of each province. The results show that although changes in productivity are positively associated with changes in public investment within the same province, there is a negative relationship between productivity changes and changes in public investment in other regions.