The relationship of telomere length to baseline corticosterone levels in nestlings of an altricial passerine bird in natural populations

Indexación: Web of Science; Scopus.Background: Environmental stressors increase the secretion of glucocorticoids that in turn can shorten telomeres via oxidative damage. Modification of telomere length, as a result of adversity faced early in life, can modify an individual's phenotype. Studies in captivity have suggested a relationship between glucocorticoids and telomere length in developing individuals, however less is known about that relationship in natural populations. Methods: In order to evaluate the effect of early environmental stressors on telomere length in natural populations, we compared baseline corticosterone (CORT) levels and telomere length in nestlings of the same age. We collected blood samples for hormone assay and telomere determination from two geographically distinct populations of the Thorn-tailed Rayadito (Aphrastura spinicauda) that differed in brood size; nestlings body mass and primary productivity. Within each population we used path analysis to evaluate the relationship between brood size, body mass, baseline CORT and telomere length. Results: Within each distinct population, path coefficients showed a positive relationship between brood size and baseline CORT and a strong and negative correlation between baseline CORT and telomere length. In general, nestlings that presented higher baseline CORT levels tended to present shorter telomeres. When comparing populations it was the low latitude population that presented higher levels of baseline CORT and shorter telomere length. Conclusions: Taken together our results reveal the importance of the condition experienced early in life in affecting telomere length, and the relevance of integrative studies carried out in natural conditions.https://frontiersinzoology.biomedcentral.com/articles/10.1186/s12983-016-0133-

The relationship of telomere length to baseline corticosterone levels in nestlings of an altricial passerine bird in natural populations.

BackgroundEnvironmental stressors increase the secretion of glucocorticoids that in turn can shorten telomeres via oxidative damage. Modification of telomere length, as a result of adversity faced early in life, can modify an individual's phenotype. Studies in captivity have suggested a relationship between glucocorticoids and telomere length in developing individuals, however less is known about that relationship in natural populations.MethodsIn order to evaluate the effect of early environmental stressors on telomere length in natural populations, we compared baseline corticosterone (CORT) levels and telomere length in nestlings of the same age. We collected blood samples for hormone assay and telomere determination from two geographically distinct populations of the Thorn-tailed Rayadito (Aphrastura spinicauda) that differed in brood size; nestlings body mass and primary productivity. Within each population we used path analysis to evaluate the relationship between brood size, body mass, baseline CORT and telomere length.ResultsWithin each distinct population, path coefficients showed a positive relationship between brood size and baseline CORT and a strong and negative correlation between baseline CORT and telomere length. In general, nestlings that presented higher baseline CORT levels tended to present shorter telomeres. When comparing populations it was the low latitude population that presented higher levels of baseline CORT and shorter telomere length.ConclusionsTaken together our results reveal the importance of the condition experienced early in life in affecting telomere length, and the relevance of integrative studies carried out in natural conditions

The impact of innovation and technology on microfinance sustainable governance

Technical or social innovation, concerning also the creation and commercialization of new products, strategies and management, has a deep actual - and especially trendy - impact on microfinance institutions (MFIs), contributing to reshape their business model, with an impact on their overall risk profile. Innovation is mostly an opportunity even for MF risk mitigation, considering its pervasive impact on risk factors. This original analysis is addressing, in a multidisciplinary and innovative comprehensive way, apparently weakly related topics such as MF governance, and IT issues, within recessionary cycles. This hardly investigated frontier faces key trendy issues, which are likely to deeply reengineer the relationship among different stakeholders, as it has already happened, on a different and more sophisticated scale, with traditional banking. To the extent that technology (with access to Internet, social networks, cashless electronic payments, etc.) reshapes the equilibriums among different stakeholders, it is likely to have important – albeit under-investigated - corporate governance consequences, softening the conflicts of interest among stakeholders and reinforcing the business model, making it more resilient during recessions, with positive externalities on both sustainability and outreach

VARIAZIONI GIORNALIERE DEI LIVELLI PLASMATICI DEL BDNF E DEL CORTISOLO IN DONNE FERTILI NORMOMESTRUATE, IN DONNE IN TERAPIA CONTRACCETTIVA ORALE ED IN POSTMENOPAUSA

Il brain derived neurotrophic factor (BDNF) fa parte della famiglia delle neurotrofine a cui appartengono anche il fattore di crescita neuronale (GNF), la neurotrofina-3 (NT-3) e la neurotrofina-4/5 (NT 4-5). E’ una proteina omodimerica di 25 KDa abbondantemente presente nel sistema nervoso centrale e periferico, soprattutto al livello dell’ipotalamo, dell’ippocampo, della corteccia cerebrale (in particolare nel lobo temporale e occipitale, nell’insula e nella corteccia sensitiva e motoria) e dell’amigdala. Agisce mediante l'attivazione dei recettori p75NGFR e TrkB, e svolge una vasta gamma di funzioni. Durante lo sviluppo gioca un ruolo fondamentale nella sopravvivenza, migrazione, differenziazione fenotipica neuronale nonché nella crescita degli assoni e dei dendriti e nella formazione delle sinapsi. Nella vita adulta la sua funzione principale è quella di regolare la plasticità sinaptica ed è implicato nei processi di apprendimento, nella memoria e nel comportamento. Diversi studi hanno dimostrato un’alterata produzione e secrezione di questa neurotrofina in patologie correlate allo stress e nelle malattie neurodegenerative. Infatti nella sindrome di Alzheimer e in quella di Parkinson sono stati riscontrati ridotti livelli di BDNF; lo stesso dicasi per patologie psichiatriche quali la depressione maggiore, la schizofrenia e i disturbi dell’alimentazione. Sebbene il BDNF sia presente prevalentemente nel sistema nervoso centrale e periferico, è stato riscontrato anche nel siero con concentrazioni dieci volte più alte di quelle plasmatiche, nelle cellule endoteliali e muscolari lisce e nel liquido follicolare. Recentemente si è visto che esiste una stretta correlazione tra livelli di estrogeni e di BDNF: infatti i livelli di neurotrofina seguono l’andamento estrogenico nelle varie fasi del ciclo ovarico e si riducono in menopausa. Anche i glucocorticoidi sembrano coinvolti nella regolazione del BDNF. Inoltre diversi studi hanno indicato variazioni cicliche nell’espressione del rec trkB e nel BDNF durante le 24 h. Recentemente è stato ipotizzato che il BDNF possa essere coinvolto nella regolazione dell’attività del nucleo soprachiasmatico. Il NSC rappresenta l’oscillatore endogeno e il primordiale orologio biologico nei mammiferi. Più specificatamente il NSC è il pacemaker centrale che genera e controlla le oscillazioni circadiane endogene di ormoni come il cortisolo e le gonadotropine. In un precedente studio è stata evidenziata una correlazione tra il BDNF e le variazioni circadiane del cortisolo negli uomini avendo dimostrato un profilo di secrezione del BDNF simile a quello del cortisolo. Lo scopo del nostro studio è stato quello di valutare: • se il BDNF nelle donne possiede oppure no un ritmo circadiano • se questo sia correlato con quello del cortisolo. • se lo stato ormonale influenzi le variazioni diurne del BDNF Hanno partecipato allo studio 30 donne afferite all’ ambulatorio ginecologico della nostra clinica che sono state suddivise in 3 gruppi: 1° gruppo (N°10 donne fertili) , 2° gruppo (N°10 donne in terapia con EP) e 3° gruppo (N°10 donne in postmenopausa). Abbiamo valutato i livelli basali di BDNF e cortisolo dopo digiuno notturno in tutti i soggetti ad intervalli regolari di 4 ore (8:00, 12:00, 16:00, 20:00, 24:00). BDNF e estradiolo sono stati campionati durante la fase follicolare e luteale nelle donne fertili ed una volta al mese nelle donne in terapia con EP ed in postmenopausa. I valori plasmatici di BDNF sono stai valutati con metodo ELISA mentre quelli di E2 e di cortisolo, sono stati valutati con metodo RIA. Per quello che riguarda i risultati i livelli di BDNF in fase luteale sono risultati significativamente piu' elevati rispetto a quelli in fase follicolare nelle donne fertili (p<0.001). Nelle donne in terapia con EP, i livelli basali di BDNF erano simili ai livelli di BDNF in fase follicolare, mentre nelle donne in postmenopausa, erano significativamente piu' bassi (p<0.001). Il BDNF ha mostrato un ritmo diurno nelle donne fertili in fase follicolare e nelle donne in terapia con EP, così come in postmenopausa mentre tale ritmo non è presente in fase luteale. L’andamento dei livelli giornalieri del BDNF ricalca il ritmo circadiano del cortisolo con valori significativamente più alti alle 8 del mattino che decrescono in maniera significativa durante il giorno. In conclusione il BDNF subisce delle variazioni diurne nelle donne in modo analogo a quanto osservato per il cortisolo. L'ampiezza della variazione dei livelli plasmatici di BDNF sembra essere influenzata dalla funzione ovarica. Interazioni tra il BDNF, l' asse ipotalamo-ipofisi-surrene e gli steroidi sessuali sembrano giocare un ruolo critico nella biologia dell'omeostasi e dell’adattamento nell’uomo

Matching Financial Closeness with Social Distancing: Networking Digital Platforms within a Corporate Governance Ecosystem

The Covid-19 – Coronavirus pandemic has rapidly spread around the world, demanding for physical social distancing measures as a strategy to soften contagion. Whereas social closeness proves dangerous, financial proximity is increasingly needed. It can be guaranteed by FinTechs or technological devices and applications, like digital platforms. Exploiting their networking properties, platforms may be represented by bridging nodes like Mobile banking (M-banking) hotspots. M-banking and FinTech applications are fully consistent with physical distance prescriptions, and so presents a Covid 19-compliant strategy that eases financial inclusion, allowing for 24/7 operativity. This is essential in poor environments where healthcare systems are weak, and prompt liquidity is needed for survival. M-banking is also a remedy against bank desertification, caused by many factors that include the decrease of “physical” bank branches. Based on these premises, this study proposes an innovative interpretation of the networking properties of digital platforms and M-banking that represent a new – virtual – stakeholder, showing how they impact on corporate governance interactions among composite stakeholders. Due to their scalability, platforms foster cooperative value co-creating patterns among cooperating stakeholders, with deep albeit still under investigated governance implications. Network governance is a novel approach to the stakeholders' ecosystem, and its value-adding phisical and virtual interactions. The paper shows how to match virtual financial proximity with apparently contradicting social distancing. This study represents an advance in the current corporate governance literature, as it investigates about its smart (digital) extensions that can represent a shield against pandemic adversities, permanently reducing transaction costs and information asymmetries

Uruguay. Historia Contemporánea (3 tomos) Montevideo, Fundación Mapfre-Editorial Planeta, 2016.

(2016) Montevideo, Fundación Mapfre-Editorial Planeta, 3 tomo

Variation in fine-scale genetic structure and local dispersal patterns between peripheral populations of a South American passerine bird

Indexación: Scopus.The distribution of suitable habitat influences natal and breeding dispersal at small spatial scales, resulting in strong microgeographic genetic structure. Although environmental variation can promote interpopulation differences in dispersal behavior and local spatial patterns, the effects of distinct ecological conditions on within-species variation in dispersal strategies and in fine-scale genetic structure remain poorly understood. We studied local dispersal and fine-scale genetic structure in the thorn-tailed rayadito (Aphrastura spinicauda), a South American bird that breeds along a wide latitudinal gradient. We combine capture-mark-recapture data from eight breeding seasons and molecular genetics to compare two peripheral populations with contrasting environments in Chile: Navarino Island, a continuous and low density habitat, and Fray Jorge National Park, a fragmented, densely populated and more stressful environment. Natal dispersal showed no sex bias in Navarino but was female-biased in the more dense population in Fray Jorge. In the latter, male movements were restricted, and some birds seemed to skip breeding in their first year, suggesting habitat saturation. Breeding dispersal was limited in both populations, with males being more philopatric than females. Spatial genetic autocorrelation analyzes using 13 polymorphic microsatellite loci confirmed the observed dispersal patterns: a fine-scale genetic structure was only detectable for males in Fray Jorge for distances up to 450 m. Furthermore, two-dimensional autocorrelation analyzes and estimates of genetic relatedness indicated that related males tended to be spatially clustered in this population. Our study shows evidence for context-dependent variation in natal dispersal and corresponding local genetic structure in peripheral populations of this bird. It seems likely that the costs of dispersal are higher in the fragmented and higher density environment in Fray Jorge, particularly for males. The observed differences in microgeographic genetic structure for rayaditos might reflect the genetic consequences of population-specific responses to contrasting environmental pressures near the range limits of its distribution.http://onlinelibrary.wiley.com/doi/10.1002/ece3.3342/epd

QUALITATIVE EASING AND RISK TRANSFER FROM CORPORATIONS TO CENTRAL BANKS

When economies face deflation and de-growth, Central Banks can only activate unconventional monetary policies. Quantitative easing inflates the Central Bank balance sheet, printing money and adding liquidity to the system while qualitative easing modifies the asset composition. With qualitative easing, Central Banks absorb the risk, flattening the yield curve. Consequences for banks and corporate borrowers may be substantial. Both measures increase inflation and reduce borrowing risk premiums, with an impact on company’s balance sheet, widening economic and financial margins and decreasing the real value of debt. Corporate governance implications concern credit risk pooling, as well as (de)leverage, asset substitution and duration risk. This paper provides unprecedented analysis of the impact of ECB unconventional monetary policy on Euro-zone governance equilibriums

Cell Surface Changes of Hemopoietic Cells During Normal and Leukemic Differentiation: An Immuno-Scanning Electron Microscopy Study

Hemopoietic cells display a wide range of cell surface antigens which are either lineage specific or acquired during differentiation. Monoclonal antibodies can be used, in conjunction with colloidal gold markers, to identify under the scanning electron microscopy (SEM) at the single cell level, specific lineage or maturation stages in the hemopoietic bone marrow. Normal bone marrow cells, either gradient separated or purified by immuno-magnetic methods and leukemic cell samples, which can be considered as frozen stages of hemopoietic differentiation, have been studied with this method. Typical cell surface morphologies, which characterize immature progenitor cells and cells committed or differentiated towards the lymphoid, myeloid, erythroid and megakaryocytic lineage have been identified. Correlations between cell surface features and some hemopoietic cells functions have been attempted on the basis of these findings

MATCHING FINANCIAL CLOSENESS WITH SOCIAL DISTANCING: NETWORKING DIGITAL PLATFORMS WITHIN A CORPORATE GOVERNANCE ECOSYSTEM

The Covid-19 \u2013 Coronavirus pandemic has rapidly spread around the world, demanding for social distancing measures as a strategy to soften contagion. Whereas social closeness proves dangerous, financial proximity is increasingly needed and can be guaranteed by FinTechs or applications, like digital platforms. Networking platforms may be represented by bridging nodes like Mobile banking (M-banking) hotspots. M-banking and FinTech applications are fully consistent with distancing prescriptions and ease financial inclusion, allowing for 24/7 operativity. This study proposes an innovative interpretation of the networking properties of digital platforms and M-banking that represent a new \u2013 virtual \u2013 stakeholder, showing how they improve corporate governance interactions. Due to their scalability, platforms foster cooperative value co-creating patterns, with deep albeit still under-investigated governance implications. Network governance is a novel approach to describe the stakeholders\u201f ecosystem, and its value-adding physical and virtual interactions. The paper shows how to match virtual financial proximity with apparently contradicting social distancing. This study represents an advance in the literature, as it investigates about its smart (digital) extensions that can represent a shield against pandemic adversities, reducing transaction costs, and information asymmetries