1,107 research outputs found

    Transition from anticipatory to lag synchronization via complete synchronization in time-delay systems

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    The existence of anticipatory, complete and lag synchronization in a single system having two different time-delays, that is feedback delay τ1\tau_1 and coupling delay τ2\tau_2, is identified. The transition from anticipatory to complete synchronization and from complete to lag synchronization as a function of coupling delay τ2\tau_2 with suitable stability condition is discussed. The existence of anticipatory and lag synchronization is characterized both by the minimum of similarity function and the transition from on-off intermittency to periodic structure in laminar phase distribution.Comment: 14 Pages and 12 Figure

    Livelihood and Revenue: Role of rattans among Mongoloid tribes and settlers of Andaman and Nicobar Islands, India

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    The Andaman and Nicobar Islands, located in the Andaman Sea between peninsular India and Indo-Malaya, are part of two of the 34 mega-diversity hotspots of the world. These islands are characterized by their unique vegetation types such as littoral, mangroves, wet and semi-evergreen forests, and rainforests and for being the home for six aboriginal tribes of Negrito and Mongoloid descent. The islands are also home to a number of migrants and “settlers” from the Indian mainland and Myanmar. The aboriginal tribes and the settlers have a long history of association with the island’s bioresources. In this paper, we survey the ethnic uses of rattans, the unique climbing palms, about 63% of which are endemic to these islands. Our ethnobotanical survey revealed several uses of rattans by the Nicobarese and Shompens, the two major ethnic communities of the Nicobar Islands. In this study, besides the ethnic uses, we also estimated the revenue generated among those involved in the rattan trade (collectors, processors, and exporters)

    Are mini DNA-barcodes sufficiently informative to resolve species identities? An in silico analysis using Phyllanthus

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    DNA barcodes using certain regions of the genomic DNA have become a popular diagnostic tool to assign species specific signatures. In plants, a number of chloroplast DNA regions such as psbA-trnH of size 400 bp have been shown to successfully discriminate members of various taxa. However, the technique is not always successful, as in the case of museum specimens or samples used in raw drug trade, where the DNA is often degraded. In this context, recent studies have suggested the use of shorter stretches of the region, called mini-barcodes, to resolve species identity. The minibarcodes are relativelymore stable and easily recovered from the degraded DNA. In this study, an attempt has been made to compare the effectiveness of mini-barcodes over full-length DNA barcodes in differentiating 16 species of Phyllanthus (Phyllanthaceae) used in the raw drug trade. Using an in silico approach, mini-barcodes of varying lengths (50–200 bp) of the region psbA-trnH were generated and evaluated for their ability to resolve the 16 Phyllanthus species in comparison to the full-length DNA barcode of size 398 bp. Results have been discussed in the light of the overall utility of mini-barcodes in resolving the species identities

    Role of previous hospitalization in clinically-significant MRSA infection among HIV-infected inpatients: results of a case-control study

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    <p>Abstract</p> <p>Background</p> <p>HIV-infected subjects have high incidence rates of <it>Staphylococcus aureus </it>infections, with both methicillin-susceptible and methicillin-resistant (MRSA) strains. Possible explanations could include the high burden of colonization, the behavioral risk factors, and the frequent exposures to health care facilities of HIV-infected patients. The purpose of the study was to assess the risk factors for clinically- significant methicillin-resistant <it>Staphylococcus aureus </it>(CS-MRSA) infections in HIV-infected patients admitted to Infectious Diseases Units.</p> <p>Methods</p> <p>From January 1, 2002 to December 31, 2005, we conducted a retrospective case-control (1:2) study. We identified all the cases of CS-MRSA infections in HIV-infected patients admitted to the National Institute for Infectious Diseases (INMI) "Lazzaro Spallanzani" in the 4-year study period. A conditional logistic regression model was used to identify risk factors for CS-MRSA infection.</p> <p>Results</p> <p>We found 27 CS-MRSA infections, i.e. 0.9 CS-MRSA infections per 100 HIV-infected individuals cared for in our Institute. At multivariate analysis, independent predictors of CS-MRSA infection were cumulative hospital stay, invasive procedures in the previous year, and low CD4 cell count. Particularly, the risk for CS-MRSA increased by 14% per an increase of 5 days hospitalization in the previous year. Finally, we identified a low frequency of community-acquired MRSA infections (only 1 of 27; 3.7%) among HIV-infected patients.</p> <p>Conclusion</p> <p>Clinicians should be aware of the risk for CS-MRSA infection in the clinical management of HIV-infected patients, especially in those patients with a low CD4 cell count, longer previous hospital stay, and previous invasive procedures.</p

    Application modeling for performance evaluation on event-triggered wireless sensor networks

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    This paper presents an approach for event-triggered wireless sensor network (WSN) application modeling, aiming to evaluate the performance of WSN configurations with regards to metrics that are meaningful to specific application domains and respective end-users. It combines application, environment-generated workload and computing/communication infrastructure within a high-level modeling simulation framework, and includes modeling primitives to represent different kind of events based on different probabilities distributions. Such primitives help end-users to characterize their application workload to capture realistic scenarios. This characterization allows the performance evaluation of specific WSN configurations, including dynamic management techniques as load balancing. Extensive experimental work shows that the proposed approach is effective in verifying whether a given WSN configuration can fulfill non-functional application requirements, such as identifying the application behavior that can lead a WSN to a break point after which it cannot further maintain these requirements. Furthermore, through these experiments, we discuss the impact of different distribution probabilities to model temporal and spatial aspects of the workload on WSNs performance, considering the adoption of dynamic and decentralized load balancing approaches

    cGMP-Dependent Protein Kinase I Is Crucial for Angiogenesis and Postnatal Vasculogenesis

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    Background Endothelium-derived nitric oxide plays an important role for the bone marrow microenvironment. Since several important effects of nitric oxide are mediated by cGMP-dependent pathways, we investigated the role of the cGMP downstream effector cGMP-dependent protein kinase I (cGKI) on postnatal neovascularization. Methodology/Principal Findings In a disc neovascularization model, cGKI -/- mice showed an impaired neovascularization as compared to their wild-type (WT) littermates. Infusion of WT, but not cGKI -/- bone marrow progenitors rescued the impaired ingrowth of new vessels in cGKI-deficient mice. Bone marrow progenitors from cGKI -/- mice showed reduced proliferation and survival rates. In addition, we used cGKI alpha leucine zipper mutant (LZM) mice as model for cGKI deficiency. LZM mice harbor a mutation in the cGKI alpha leucine zipper that prevents interaction with downstream signaling molecules. Consistently, LZM mice exhibited reduced numbers of vasculogenic progenitors and impaired neovascularization following hindlimb ischemia compared to WT mice. Conclusions/Significance Our findings demonstrate that the cGMP-cGKI pathway is critical for postnatal neovascularization and establish a new role for cGKI in vasculogenesis, which is mediated by bone marrow-derived progenitors

    Spatially differentiated nitrogen supply is key in a global food–fertilizer price crisis

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    A regional geopolitical conflict and sudden massive supply disruptions have revealed vulnerabilities in our global fuel–fertilizer–food nexus. As nitrogen (N) fertilizer price spikes threaten food security, differentiated responses are required to maintain staple cereal yields across over- and underfertilized agricultural systems. Through integrated management of organic and inorganic N sources in high- to low-input cereal production systems, we estimate potential total N-fertilizer savings of 11% in India, 49% in Ethiopia and 44% in Malawi. Shifting to more cost-effective, high-N fertilizer (such as urea), combined with compost and integration of legumes, can optimize N in N-deficient systems. Better targeted and more efficient N-fertilizer use will benefit systems with surplus N. Geospatially differentiated fertilization strategies should prioritize high-N fertilizer supply to low-yield, N-deficient locations and balanced fertilization of N, P, K and micronutrients in high-yield systems. Nationally, governments can invest in extension and realign subsidies to enable and incentivize improved N management at the farm level

    Let’s not forget tautomers

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    A compound exhibits tautomerism if it can be represented by two structures that are related by an intramolecular movement of hydrogen from one atom to another. The different tautomers of a molecule usually have different molecular fingerprints, hydrophobicities and pKa’s as well as different 3D shape and electrostatic properties; additionally, proteins frequently preferentially bind a tautomer that is present in low abundance in water. As a result, the proper treatment of molecules that can tautomerize, ~25% of a database, is a challenge for every aspect of computer-aided molecular design. Library design that focuses on molecular similarity or diversity might inadvertently include similar molecules that happen to be encoded as different tautomers. Physical property measurements might not establish the properties of individual tautomers with the result that algorithms based on these measurements may be less accurate for molecules that can tautomerize—this problem influences the accuracy of filtering for library design and also traditional QSAR. Any 2D or 3D QSAR analysis must involve the decision of if or how to adjust the observed Ki or IC50 for the tautomerization equilibria. QSARs and recursive partitioning methods also involve the decision as to which tautomer(s) to use to calculate the molecular descriptors. Docking virtual screening must involve the decision as to which tautomers to include in the docking and how to account for tautomerization in the scoring. All of these decisions are more difficult because there is no extensive database of measured tautomeric ratios in both water and non-aqueous solvents and there is no consensus as to the best computational method to calculate tautomeric ratios in different environments

    Identification and Characterisation of a Novel Acylpeptide Hydrolase from Sulfolobus Solfataricus: Structural and Functional Insights

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    A novel acylpeptide hydrolase, named APEH-3Ss, was isolated from the hypertermophilic archaeon Sulfolobus solfataricus. APEH is a member of the prolyl oligopeptidase family which catalyzes the removal of acetylated amino acid residues from the N terminus of oligopeptides. The purified enzyme shows a homotrimeric structure, unique among the associate partners of the APEH cluster and, in contrast to the archaeal APEHs which show both exo/endo peptidase activities, it appears to be a “true” aminopeptidase as exemplified by its mammalian counterparts, with which it shares a similar substrate specificity. Furthermore, a comparative study on the regulation of apeh gene expression, revealed a significant but divergent alteration in the expression pattern of apeh-3Ss and apehSs (the gene encoding the previously identified APEHSs from S. solfataricus), which is induced in response to various stressful growth conditions. Hence, both APEH enzymes can be defined as stress-regulated proteins which play a complementary role in enabling the survival of S. solfataricus cells under different conditions. These results provide new structural and functional insights into S. solfataricus APEH, offering a possible explanation for the multiplicity of this enzyme in Archaea

    CCL5 regulation of mucosal chlamydial immunity and infection

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    <p>Abstract</p> <p>Background</p> <p>Following genital chlamydial infection, an early T helper type 1 (Th1)-associated immune response precedes the activation and recruitment of specific Th1 cells bearing distinct chemokine receptors, subsequently leading to the clearance of <it>Chlamydia</it>. We have shown that CCR5, a receptor for CCL5, is crucial for protective chlamydial immunity. Our laboratory and others have also demonstrated that CCL5 deficiencies found in man and animals can increase the susceptibility and progression of infectious diseases by modulating mucosal immunity. These findings suggest the CCR5-CCL5 axis is necessary for optimal chlamydial immunity. We hypothesized CCL5 is required for protective humoral and cellular immunity against <it>Chlamydia</it>.</p> <p>Results</p> <p>The present study revealed that CCR5 and CCL5 mRNAs are elevated in the spleen, iliac lymph nodes (ILNs), and genital mucosa following <it>Chlamydia muriduram </it>challenge. Antibody (Ab)-mediated inhibition of CCL5 during genital chlamydial infection suppressed humoral and Th1 > Th2 cellular responses by splenic-, ILN-, and genital mucosa-derived lymphocytes. Antigen (Ag)-specific proliferative responses of CD4<sup>+ </sup>T cells from spleen, ILNs, and genital organs also declined after CCL5 inhibition.</p> <p>Conclusion</p> <p>The suppression of these responses correlated with delayed clearance of <it>C. muriduram</it>, which indicate chlamydial immunity is mediated by Th1 immune responses driven in part by CCL5. Taken together with other studies, the data show that CCL5 mediates the temporal recruitment and activation of leukocytes to mitigate chlamydial infection through enhancing adaptive mucosal humoral and cellular immunity.</p
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