1,628 research outputs found
A methodological proposal for the complementarity of the SSM and the VSM for the analysis of viability in organizations
This paper presents a protocol that establishes the complementarity between Soft Systems Methodology (SSM) and the Viable System Model (VSM) for the analysis of viability in organizations. Various studies demonstrate the advantages of both hard and soft multimethodologies, especially in the field of operational research (OR). Relying on a literature review of multimethodology, the present research specifically focuses on papers that examine the resolution of problem situations in organizations using SSM and VSM. It subsequently addresses approaches to both methodologies and, as a result, presents the characteristics that favor complementarity. Thus, this research primarily contributes with a methodological proposal that integrates both SSM and VSM. In terms of its technical-methodological approach, this study proposes a comprehensive protocol for the integration of SSM and VSM. While some studies do extol the benefits of combining the two methodologies, a systematic protocol for their integration is still lacking. As such, the protocol presented herein consists of six steps used to diagnose or design a viable organization that includes a questionnaire for detecting organizational pathologies
Spontaneous Rotation of a Toric Implantable Collamer Lens
We present a case of toric implantable collamer lens (TICL) spontaneous rotation in a patient with myopic astigmatism. A 23-year-old female underwent TICL implantation. Preoperative uncorrected visual acuity (UCVA) was 20/800 and 20/1200, respectively, with −7.75 −4.25 × 0° and −8.25 −5.25 × 180°. The left eye achieved an UCVA of 20/30. After 3 months of successful implantation of TICL in the left eye, the patient presented with a sudden decrease in visual acuity in the left eye. UCVA was 20/100 with a refraction of +2.50 −4.50 × 165°. We observed the toric marks with a 30° rotation from the original position and decided to reposition the TICL, obtaining a final UCVA of 20/25, which remained stable at 6 months' follow-up. TICL can present a considerable rotation that compromises visual acuity. The relocation of TICL is a safe and effective procedure to recover visual acuity due to significant spontaneous TICL rotation
Systems Thinking Approach to Sustainable Performance in RAMSAR Sites
This article explores and validates the integrated use of the Viable System Model (VSM) and the Partial Least Squares Path Modeling (PLS-PM) approach to assess the sustainable management of RAMSAR sites carrying out economic activities. This work adopts a systems- thinking approach integrating systemic methodologies in three phases: 1) the VSM was first used to develop a conceptual model of the organisational problem; 2) PLS-PM was used to propose a construct to outline a solution, as well as to statistically validate the relationships proposed in the conceptual model; finally, 3) through the VSM, the relationships between actors were rethought in order to promote sustainable performance. The obtained results suggest that the joint use of VSM and PLS-PM is an effective approach that aids to the identification of relational and structural pathologies affecting the observed RAMSAR systems. It also proved useful to suggest that relationships can lead to the sustainable performance of the sites under study. It should be noted that the framework of systemic tools is constrained in its application to the organisational domain: assessing two RAMSAR areas in Mexico. Methodologically, this is the first application of the integrated use of VSM and PLS-PM to analyse the management and viability/sustainability of RAMSAR areas from an organisational perspective, opening a new avenue for the analysis and optimisation of management of such areas. This study provides tools to support actors and academics related to RAMSAR sites and opens up a discussion on how to rethink the organisational interactions in order to improve RAMSAR sites adaptive capabilities
Luminescent properties of Bi-doped polycrystalline KAlCl4
We observed an intensive near-infrared luminescence in Bi-doped KAlCl4
polycrystalline material. Luminescence dependence on the excitation wavelength
and temperature of the sample was studied. Our experimental results allow
asserting that the luminescence peaked near 1 um belongs solely to Bi+ ion
which isomorphically substitutes potassium in the crystal. It was also
demonstrated that Bi+ luminescence features strongly depend on the local ion
surroundings
CD69 is a TGF-β/1α,25-dihydroxyvitamin D3 target gene in monocytes
CD69 is a transmembrane lectin that can be expressed on most hematopoietic cells. In monocytes, it has been functionally linked to the 5-lipoxygenase pathway in which the leukotrienes, a class of highly potent inflammatory mediators, are produced. However, regarding CD69 gene expression and its regulatory mechanisms in monocytes, only scarce data are available. Here, we report that CD69 mRNA expression, analogous to that of 5-lipoxygenase, is induced by the physiologic stimuli transforming growth factor-β (TGF-β) and 1α,25-dihydroxyvitamin D3 (1α,25(OH)2D3) in monocytic cells. Comparison with T- and B-cell lines showed that the effect was specific for monocytes. CD69 expression levels were increased in a concentration-dependent manner, and kinetic analysis revealed a rapid onset of mRNA expression, indicating that CD69 is a primary TGF-β/1α,25(OH)2D3 target gene. PCR analysis of different regions of the CD69 mRNA revealed that de novo transcription was initiated and proximal and distal parts were induced concomitantly. In common with 5-lipoxygenase, no activation of 0.7 kb or ~2.3 kb promoter fragments by TGF-β and 1α,25(OH)2D3 could be observed in transient reporter assays for CD69. Analysis of mRNA stability using a transcription inhibitor and a 3′UTR reporter construct showed that TGF-β and 1α,25(OH)2D3 do not influence CD69 mRNA stability. Functional knockdown of Smad3 clearly demonstrated that upregulation of CD69 mRNA, in contrast to 5-LO, depends on Smad3. Comparative studies with different inhibitors for mitogen activated protein kinases (MAPKs) revealed that MAPK signalling is involved in CD69 gene regulation, whereas 5-lipoxygenase gene expression was only partly affected. Mechanistically, we found evidence that CD69 gene upregulation depends on TAK1-mediated p38 activation. In summary, our data indicate that CD69 gene expression, conforming with 5-lipoxygenase, is regulated monocyte-specifically by the physiologic stimuli TGF-β and 1α,25(OH)2D3 on mRNA level, although different mechanisms account for the upregulation of each gene
Trans-sialidase Stimulates Eat Me Response from Epithelial Cells
Epithelial cell invasion by the protozoan parasite Trypanosoma cruzi is enhanced by the presence of an enzyme expressed on its cell surface during the trypomastigote life cycle stage. The enzyme, trans-sialidase (TS), is a member of one of the largest gene families expressed by the parasite and the role of its activity in mediating epithelial cell entry has not hitherto been understood. Here we show that the T. cruzi TS generates an eat me signal which is capable of enabling epithelial cell entry. We have utilized purified, recombinant, active (TcTS) and inactive (TcTS2V0) TS coated onto beads to challenge an epithelial cell line. We find that TS activity acts upon G protein coupled receptors present at the epithelial cell synapse with the coated bead, thereby enhancing cell entry. By so doing, we provide evidence that TS proteins bind glycans, mediate the formation of distinct synaptic domains and promote macropinocytotic uptake of microparticles into a perinuclear compartment in a manner which may emulate entosis
Wide-Scale Analysis of Human Functional Transcription Factor Binding Reveals a Strong Bias towards the Transcription Start Site
We introduce a novel method to screen the promoters of a set of genes with
shared biological function, against a precompiled library of motifs, and find
those motifs which are statistically over-represented in the gene set. The gene
sets were obtained from the functional Gene Ontology (GO) classification; for
each set and motif we optimized the sequence similarity score threshold,
independently for every location window (measured with respect to the TSS),
taking into account the location dependent nucleotide heterogeneity along the
promoters of the target genes. We performed a high throughput analysis,
searching the promoters (from 200bp downstream to 1000bp upstream the TSS), of
more than 8000 human and 23,000 mouse genes, for 134 functional Gene Ontology
classes and for 412 known DNA motifs. When combined with binding site and
location conservation between human and mouse, the method identifies with high
probability functional binding sites that regulate groups of biologically
related genes. We found many location-sensitive functional binding events and
showed that they clustered close to the TSS. Our method and findings were put
to several experimental tests. By allowing a "flexible" threshold and combining
our functional class and location specific search method with conservation
between human and mouse, we are able to identify reliably functional TF binding
sites. This is an essential step towards constructing regulatory networks and
elucidating the design principles that govern transcriptional regulation of
expression. The promoter region proximal to the TSS appears to be of central
importance for regulation of transcription in human and mouse, just as it is in
bacteria and yeast.Comment: 31 pages, including Supplementary Information and figure
Extraordinarily high biomass benthic community on Southern Ocean seamounts
We describe a previously unknown assemblage of seamount-associated megabenthos that has by far the highest peak biomass reported in the deep-sea outside of vent communities. The assemblage was found at depths of 2–2.5 km on rocky geomorphic features off the southeast coast of Australia, in an area near the Sub-Antarctic Zone characterised by high rates of surface productivity and carbon export to the deep-ocean. These conditions, and the taxa in the assemblage, are widely distributed around the Southern mid-latitudes, suggesting the high-biomass assemblage is also likely to be widespread. The role of this assemblage in regional ecosystem and carbon dynamics and its sensitivities to anthropogenic impacts are unknown. The discovery highlights the lack of information on deep-sea biota worldwide and the potential for unanticipated
impacts of deep-sea exploitation
Protein Pattern Formation
Protein pattern formation is essential for the spatial organization of many
intracellular processes like cell division, flagellum positioning, and
chemotaxis. A prominent example of intracellular patterns are the oscillatory
pole-to-pole oscillations of Min proteins in \textit{E. coli} whose biological
function is to ensure precise cell division. Cell polarization, a prerequisite
for processes such as stem cell differentiation and cell polarity in yeast, is
also mediated by a diffusion-reaction process. More generally, these functional
modules of cells serve as model systems for self-organization, one of the core
principles of life. Under which conditions spatio-temporal patterns emerge, and
how these patterns are regulated by biochemical and geometrical factors are
major aspects of current research. Here we review recent theoretical and
experimental advances in the field of intracellular pattern formation, focusing
on general design principles and fundamental physical mechanisms.Comment: 17 pages, 14 figures, review articl
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