322 research outputs found
ModĂšle multi-agents pour la simulation de la dynamique de carbone Ă l'Ă©chelle du terroir villageois
Un systĂšme multi-agents (SMA) a Ă©tĂ© conçu et mis en oeuvre en vue d'Ă©tudier la dynamique des ressources organiques et azotĂ©e d'un terroir africain. Les simulations rĂ©alisĂ©es ont permis de mesurer l'impact des modes de gestion sur les ressources dans le long terme. Trois types d'enquĂȘtes ont Ă©tĂ© nĂ©cessaires pour collecter les donnĂ©es nĂ©cessaires. Un premier modĂšle Ă l'Ă©chelle de la parcelle a permis de simuler le stockage du carbone et de l'azote dans les sols et dans la biomasse vĂ©gĂ©tale. Ensuite la dĂ©finition des rĂšgles individuelles et collectives de dĂ©cision et de gestion des exploitations agricoles et du terroir ont nĂ©cessitĂ© des enquĂȘtes approfondies avec les principaux groupes utilisant le terroir. . Pour la conception informatique du modĂšle, le formalisme UML a Ă©tĂ© utilisĂ©. La reprĂ©sentation statique et dynamique du modĂšle a Ă©tĂ© formalisĂ©e sur la plate forme de modĂ©lisation CORMAS. . La mĂ©thode dĂ©veloppĂ©e est appelĂ©e MIROT ModĂ©lisation IntĂ©grĂ©e de la dynamique des Ressources Organiques et analyse de viabilitĂ© de Terroirs agro-sylvo-pastoraux des savanes ouest africaines). Le modĂšle MIROT utilise un fond de carte du terroir avec des contraintes spatiales pour simuler le fonctionnement de celui-ci
Kerr-microresonator solitons from a chirped background
We demonstrate protected single-soliton formation and operation in a Kerr
microresonator using a phase-modulated pump laser. Phase modulation gives rise
to spatially varying effective loss and detuning parameters, which in turn lead
to an operation regime in which multi-soliton degeneracy is lifted and a single
soliton is the only observable behavior. Direct excitation of single solitons
is indicated by observed reversal of the characteristic 'soliton step.' Phase
modulation also enables precise control of the soliton pulse train's
properties, and measured dynamics agree closely with simulations. We show that
the technique can be extended to high repetition-frequency Kerr solitons
through subharmonic phase modulation. These results facilitate straightforward
generation and control of Kerr-soliton microcombs for integrated photonics
systems
Anti-proliferative effect of Scoparia dulcis L. against bacterial and fungal strains
Scoparia dulcis L. was sequentially extracted with hexane, chloroform and methanol and soaked with aqueous-acetone (80%) to check for its antimicrobial activities against five bacterial and four fungal strains.250ÎŒg of each extract loaded on a whatman paper disc exhibited significant antimicrobial activities on all the fungus and against Gram-negative and Gram-positive bacteria. Therefore, P. mirabilis is less sensitive to all the extracts while B. cereus, a Ăą-lactamase producer bacterium, was resistant to the activity of the polar methanol and aqueous-acetone extracts. By the microdilution method, the most active extracts were chloroform extract on B. cereus with minimal inhibitory concentration (MIC) of 1.56 mg/ml and Aqueous-acetone extract on S. typhimurium (MIC = 1.56 mg/ml); the antifungal activity was strongest for hexane extract (MIC = 6.25 mg/ml) on both A. niger and P. roquefortii.Keywords: Scoparia dulcis, Antibacterial, Antifungal, Polyphenols
Multi Agents Model for carbone dynamic simulation at village area scale
Un systĂšme multi-agents (SMA) a Ă©tĂ© conçu et mis en Ćuvre en vue dâĂ©tudier la dynamique des ressources organiques et azotĂ©e dâun terroir africain. Les simulations rĂ©alisĂ©es ont permis de mesurer lâimpact des modes de gestion sur les ressources dans le long terme.
Trois types dâenquĂȘtes ont Ă©tĂ© nĂ©cessaires pour collecter les donnĂ©es nĂ©cessaires. Un premier modĂšle Ă lâĂ©chelle de la parcelle a permis de simuler le stockage du carbone et de lâazote dans les sols et dans la biomasse vĂ©gĂ©tale. Ensuite la dĂ©finition des rĂšgles individuelles et collectives de dĂ©cision et de gestion des exploitations agricoles et du terroir ont nĂ©cessitĂ© des enquĂȘtes approfondies avec les principaux groupes utilisant le terroir. . Pour la conception informatique du modĂšle, le formalisme UML a Ă©tĂ© utilisĂ©. La reprĂ©sentation statique et dynamique du modĂšle a Ă©tĂ© formalisĂ©e sur la plate forme de modĂ©lisation CORMAS. . La mĂ©thode dĂ©veloppĂ©e est appelĂ©e MIROT ModĂ©lisation IntĂ©grĂ©e de la dynamique des Ressources Organiques et analyse de viabilitĂ© de Terroirs agro-sylvo-pastoraux
des savanes ouest africaines). Le modĂšle MIROT utilise un fond de carte du terroir avec des contraintes spatiales pour simuler le fonctionnement de celui-ci
Phase-coherent microwave-to-optical link with a self-referenced microcomb
Precise measurements of the frequencies of light waves have become common with mode-locked laser frequency combs1. Despite their huge success, optical frequency combs currently remain bulky and expensive laboratory devices. Integrated photonic microresonators are promising candidates for comb generators in out-of-the-lab applications, with the potential for reductions in cost, power consumption and size. Such advances will significantly impact fields ranging from spectroscopy and trace gas sensing to astronomy, communications and atomic time-keeping. Yet, in spite of the remarkable progress shown over recent years, microresonator frequency combs (âmicrocombsâ) have been without the key function of direct fâ2f self-referencing, which enables precise determination of the absolute frequency of each comb line. Here, we realize this missing element using a 16.4â
GHz microcomb that is coherently broadened to an octave-spanning spectrum and subsequently fully phase-stabilized to an atomic clock. We show phase-coherent control of the comb and demonstrate its low-noise operation
Phase Coherent Link of an Atomic Clock to a Self-Referenced Microresonator Frequency Comb
The counting and control of optical cycles of light has become common with
modelocked laser frequency combs. But even with advances in laser technology,
modelocked laser combs remain bulk-component devices that are hand-assembled.
In contrast, a frequency comb based on the Kerr-nonlinearity in a dielectric
microresonator will enable frequency comb functionality in a micro-fabricated
and chip-integrated package suitable for use in a wide-range of environments.
Such an advance will significantly impact fields ranging from spectroscopy and
trace gas sensing, to astronomy, communications, atomic time keeping and
photonic data processing. Yet in spite of the remarkable progress shown over
the past years, microresonator frequency combs ("microcombs") have still been
without the key function of direct f-2f self-referencing and phase-coherent
frequency control that will be critical for enabling their full potential. Here
we realize these missing elements using a low-noise 16.4 GHz silicon chip
microcomb that is coherently broadened from its initial 1550 nm wavelength and
subsequently f-2f self-referenced and phase-stabilized to an atomic clock. With
this advance, we not only realize the highest repetition rate octave-span
frequency comb ever achieved, but we highlight the low-noise microcomb
properties that support highest atomic clock limited frequency stability
Multiplex serum protein analysis reveals potential mechanisms and markers of response to hyperimmune caprine serum in systemic sclerosis
BACKGROUND: Hyperimmune caprine serum (HICS) is a novel biological therapy with potential benefit for skin in established diffuse cutaneous systemic sclerosis. Here we report multiplex protein analysis of blood samples from a placebo-controlled phase II clinical trial and explore mechanisms of action and markers of response. METHODS: Patients were treated with HICS (nâ=â10) or placebo (nâ=â10) over 26 weeks, with follow-up open-label treatment to 52 weeks in 14 patients. Serum or plasma samples at baseline, 26 and 52 weeks were analysed using multiplex or individual immunoassays for 41 proteins. Patterns of change were analysed by clustering using Netwalker 1.0, Pearson coefficient and significance analysis of microarrays (SAM) correction. RESULTS: Cluster analysis, SAM multiplex testing and paired comparison of individual analytes identified proteins that were upregulated or downregulated during treatment with HICS. There was upregulation of the hypothalamo-pituitary-adrenal axis after HICS treatment evidenced by increases in α-MSH and ACTH in cases treated with HICS. Interestingly, significant increase in PIIINP was associated with HICS treatment and improved MRSS suggesting that this may be a marker of extracellular matrix turnover. Other relevant factors reduced in HICS-treated patients compared with controls, although not reaching statistical significance included COMP, CCL2, IL6, TIMP2, Fractalkine and TGFÎČ1 levels. CONCLUSIONS: Our results suggest mechanisms of action for HICS, including upregulation of α-MSH, that has been shown to be anti-fibrotic in preclinical models, and possible markers to be included in future trials targeting skin in diffuse cutaneous systemic sclerosis. TRIAL REGISTRATION: Eudract, No. 2007-003122-24. ClinTrials.gov, No. NCT00769028 . Registered 7 October 2008
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