Vector-borne diseases with non-stationary vector populations: the case of growing and decaying populations

Since the last century, deterministic compartmental models have emerged as powerful tools to predict and control epidemic outbreaks, in many cases helping to mitigate their impacts. A key quantity for these models is the so-called Basic Reproduction Number, that measures the number of secondary infections produced by an initial infected individual in a fully susceptible population. Some methods have been developed to allow the direct computation of this quantity provided that some conditions are fulfilled, such that the model has a pre-pandemic disease-free equilibrium state. This condition is only fulfilled when the populations are stationary. In the case of vector-borne diseases, this implies that the vector birth and death rates need to be balanced, what is not fulfilled in many realistic cases in which the vector population grow or decrease. Here we develop a vector-borne epidemic model with growing and decaying vector populations and study the conditions under which the standard methods to compute $R_0$ work and discuss an alternative when they fail. We also show that growing vector populations produce a delay in the epidemic dynamics when compared to the case of the stationary vector population. Finally, we discuss the conditions under which the model can be reduced to the SIR model with fewer compartments and parameters, which helps in solving the problem of parameter unidentifiability of many vector-borne epidemic models.Comment: 16 pages, 6 figure

Is Centaurus A special? A neutral hydrogen perspective

Due to the proximity, the neutral hydrogen belonging to Centaurus A can be observed at high resolution with good sensitivity. This allows to study the morphology and kinematics in detail in order to understand the evolution of this radio-loud source (e.g. merger history, AGN activity). At the same time, it is important to compare the results to other sources of the same class (i.e. early-type galaxies in general and radio galaxies in particular) to see how Centaurus A fits into the global picture of early-type/radio galaxy evolution. The amount of HI, the morphology of a warped disk with HI clouds surrounding the disk and the regular kinematics of the inner part of the HI disk are not unusual for early-type galaxies. The growing evidence that mergers are not necessarily responsible for AGN activity fits with the observational result that the recent merger event in Centaurus A is not connected to the current phase of activity. Based on these results, we conclude that Centaurus A has typical neutral hydrogen properties for an early-type and radio galaxy and it can therefore - from an HI perspective - be seen as a typical example of its class.Comment: submitted to PASA; 7 pages, 4 figure

Functional interactions in patients with hemianopia: A graph theory-based connectivity study of resting fMRI signal

Podeu consultar les dades primàries associades a l'article a: http://hdl.handle.net/2445/136617The assessment of task-independent functional connectivity (FC) after a lesion causing hemianopia remains an uncovered topic and represents a crucial point to better understand the neural basis of blindsight (i.e. unconscious visually triggered behavior) and visual awareness. In this light, we evaluated functional connectivity (FC) in 10 hemianopic patients and 10 healthy controls in a resting state paradigm. The main aim of this study is twofold: first of all we focused on the description and assessment of density and intensity of functional connectivity and network topology with and without a lesion affecting the visual pathway, and then we extracted and statistically compared network metrics, focusing on functional segregation, integration and specialization. Moreover, a study of 3-cycle triangles with prominent connectivity was conducted to analyze functional segregation calculated as the area of each triangle created connecting three neighboring nodes. To achieve these purposes we applied a graph theory-based approach, starting from Pearson correlation coefficients extracted from pairs of regions of interest. In these analyses we focused on the FC extracted by the whole brain as well as by four resting state networks: The Visual (VN), Salience (SN), Attention (AN) and Default Mode Network (DMN), to assess brain functional reorganization following the injury. The results showed a general decrease in density and intensity of functional connections, that leads to a less compact structure characterized by decrease in functional integration, segregation and in the number of interconnected hubs in both the Visual Network and the whole brain, despite an increase in long-range inter-modules connections (occipito-frontal connections). Indeed, the VN was the most affected network, characterized by a decrease in intra- and inter-network connections and by a less compact topology, with less interconnected nodes. Surprisingly, we observed a higher functional integration in the DMN and in the AN regardless of the lesion extent, that may indicate a functional reorganization of the brain following the injury, trying to compensate for the general reduced connectivity. Finally we observed an increase in functional specialization (lower between-network connectivity) and in inter-networks functional segregation, which is reflected in a less compact network topology, highly organized in functional clusters. These descriptive findings provide new insight on the spontaneous brain activity in hemianopic patients by showing an alteration in the intrinsic architecture of a large-scale brain system that goes beyond the impairment of a single RSN

Genome-wide linkage analysis of congenital heart defects using MOD score analysis identifies two novel loci

Background: Congenital heart defects (CHD) is the most common cause of death from a congenital structure abnormality in newborns and is often associated with fetal loss. There are many types of CHD. Human genetic studies have identified genes that are responsible for the inheritance of a particular type of CHD and for some types of CHD previously thought to be sporadic. However, occasionally different members of the same family might have anatomically distinct defects — for instance, one member with atrial septal defect, one with tetralogy of Fallot, and one with ventricular septal defect. Our objective is to identify susceptibility loci for CHD in families affected by distinct defects. The occurrence of these apparently discordant clinical phenotypes within one family might hint at a genetic framework common to most types of CHD. Results: We performed a genome-wide linkage analysis using MOD score analysis in families with diverse CHD. Significant linkage was obtained in two regions, at chromosome 15 (15q26.3, Pempirical = 0.0004) and at chromosome 18 (18q21.2, Pempirical = 0.0005). Conclusions: In these two novel regions four candidate genes are located: SELS, SNRPA1, and PCSK6 on 15q26.3, and TCF4 on 18q21.2. The new loci reported here have not previously been described in connection with CHD. Although further studies in other cohorts are needed to confirm these findings, the results presented here together with recent insight into how the heart normally develops will improve the understanding of CHDThis study was supported by the grants from the Instituto de Salud Carlos III (08–1363 and 11–0699) of the Spanish Ministry of Health and by grant Str643/4-1 of the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation)

Biomolecular insights into North African-related ancestry, mobility and diet in eleventh-century Al-Andalus

Historical records document medieval immigration from North Africa to Iberia to create Islamic al-Andalus. Here, we present a low-coverage genome of an eleventh century CE man buried in an Islamic necropolis in Segorbe, near Valencia, Spain. Uniparental lineages indicate North African ancestry, but at the autosomal level he displays a mosaic of North African and European-like ancestries, distinct from any present-day population. Altogether, the genome-wide evidence, stable isotope results and the age of the burial indicate that his ancestry was ultimately a result of admixture between recently arrived Amazigh people (Berbers) and the population inhabiting the Peninsula prior to the Islamic conquest. We detect differences between our sample and a previously published group of contemporary individuals from Valencia, exemplifying how detailed, small-scale aDNA studies can illuminate fine-grained regional and temporal differences. His genome demonstrates how ancient DNA studies can capture portraits of past genetic variation that have been erased by later demographic shifts-in this case, most likely the seventeenth century CE expulsion of formerly Islamic communities as tolerance dissipated following the Reconquista by the Catholic kingdoms of the north

Molecular Gas in Infrared Ultraluminous QSO Hosts

We report CO detections in 17 out of 19 infrared ultraluminous QSO (IR QSO) hosts observed with the IRAM 30m telescope. The cold molecular gas reservoir in these objects is in a range of 0.2--2.1$\times 10^{10}M_\odot$ (adopting a CO-to-${\rm H_2}$ conversion factor $\alpha_{\rm CO}=0.8 M_\odot {\rm (K km s^{-1} pc^2)^{-1}}$). We find that the molecular gas properties of IR QSOs, such as the molecular gas mass, star formation efficiency ($L_{\rm FIR}/L^\prime_{\rm CO}$) and the CO (1-0) line widths, are indistinguishable from those of local ultraluminous infrared galaxies (ULIRGs). A comparison of low- and high-redshift CO detected QSOs reveals a tight correlation between L$_{\rm FIR}$ and $L^\prime_{\rm CO(1-0)}$ for all QSOs. This suggests that, similar to ULIRGs, the far-infrared emissions of all QSOs are mainly from dust heated by star formation rather than by active galactic nuclei (AGNs), confirming similar findings from mid-infrared spectroscopic observations by {\it Spitzer}. A correlation between the AGN-associated bolometric luminosities and the CO line luminosities suggests that star formation and AGNs draw from the same reservoir of gas and there is a link between star formation on $\sim$ kpc scale and the central black hole accretion process on much smaller scales.Comment: 30 pages, 9 figures, accepted for publication in The Astrophysical Journa

Fine Mapping of 10q and 18q for Familial Alzheimer's Disease in Caribbean Hispanics

Familial Alzheimer's disease (AD [MIM 104300]) has been a focus of intense investigation, primarily in Caucasian families from Europe and North America families. Although the late-onset form of familial AD, beginning after age 65 years, has been linked to regions on chromosomes 10q and 12p, the specific genetic variants have not yet been consistently identified. Using a unique cohort of families of Caribbean Hispanics ancestry, we screened the genome using 340 markers on 490 family members from 96 families with predominantly late-onset AD. We observed the strongest support for linkage on 18q (LOD=3.14). However, 17 additional markers (chromosomes 1-6, 8, 10, 12, and 14) exceeded a two-point LOD score of 1.0 under the affecteds-only autosomal dominant model or affected sibpair model. As we previously reported the fine-mapping effort on 12p showing modest evidence of linkage, we focused our fine-mapping efforts on two other candidate regions in the current report, namely 10q and 18q. We added 31 family members and eight additional Caribbean Hispanic families to fine map 10q and 18q. With additional microsatellite markers, the evidence for linkage for 18q strengthened near 112 cM, where the two-point LOD score for D18S541 was 3.37 and the highest NPL score in that region was 3.65 (P=0.000177). This narrow region contains a small number of genes expressed in the brain. However, at 10q (134-138 cM), the NPL score decreased from 3.15 (P=0.000486) to 2.1 (P=0.0218), but two broad peaks remained overlapping with previously reported peaks. Our results provide modest support for linkage on 10q and 12p in this cohort of Caribbean Hispanic families with familial Alzheimer's disease, and strong evidence for a new locus on 18

The Sub-State Politics of Welfare in Italy: Assessing the Effect of Territorial Mobilization on the Development of Region-Specific Social Governance

This article demonstrates that the political mobilization of regional identities through the creation of regionalist parties has positively impacted on the development of region-specific models of welfare governance in Italy. This means that, in a decentralized country, the ‘centre-periphery’ cleavage may significantly influence the sub-state politics of welfare