592 research outputs found
As above, so below: whole transcriptome profiling demonstrates strong molecular similarities between avian dorsal and ventral pallial subdivisions
Over the last two decades, beginning withthe Avian Brain Nomenclature Forum in2000, major revisions have been made to our understanding of the organization andnomenclature of the avian brain. However, there are still unresolved questions on avianpallial organization, particularly whether the cells above the vestigial ventricle representdistinct populations to those below it or similar populations. To test these two hypothe-ses, we profiled the transcriptomes of the major avian pallial subdivisions dorsal and ven-tral to the vestigial ventricle boundary using RNA sequencing and a new zebra finchgenome assembly containing about 22,000annotated, complete genes. We found thatthe transcriptomes of neural populations above and below the ventricle were remarkablysimilar. Each subdivision in dorsal pallium (Wulst) had a corresponding molecular counter-part in the ventral pallium (dorsal ventricularridge). In turn, each corresponding subdivi-sion exhibited shared gene co-expression modules that contained gene sets enriched infunctional specializations, such as anatomical structure development, synaptic transmis-sion, signaling, and neurogenesis. Thesefindings are more in line with the continuumhypothesis of avian brain subdivision organization above and below the vestigial ventriclespace, with the pallium as a whole consisting offour major cell populations (intercalatedpallium, mesopallium, hyper-nidopallium, andarcopallium) instead of seven (hyperpalliumapicale, interstitial hyperpallium apicale, intercalated hyperpallium, hyperpalliumdensocellare, mesopallium, nidopallium, and arcopallium). We suggest adopting a morestreamlined hierarchical naming system thatreflects the robust similarities in geneexpression, neural connectivity motifs, and function. These findings have important impli-cations for our understanding of overall vertebrate brain evolution
The evolutionary history and genomics of European blackcap migration
Seasonal migration is a taxonomically widespread behaviour that integrates across many traits. The European blackcap exhibits enormous variation in migration and is renowned for research on its evolution and genetic basis. We assembled a reference genome for blackcaps and obtained whole genome resequencing data from individuals across its breeding range. Analyses of population structure and demography suggested divergence began ~30,000 ya, with evidence for one admixture event between migrant and resident continent birds ~5000 ya. The propensity to migrate, orientation and distance of migration all map to a small number of genomic regions that do not overlap with results from other species, suggesting that there are multiple ways to generate variation in migration. Strongly associated single nucleotide polymorphisms (SNPs) were located in regulatory regions of candidate genes that may serve as major regulators of the migratory syndrome. Evidence for selection on shared variation was documented, providing a mechanism by which rapid changes may evolve
Virtual signatures of dark sectors in Higgs couplings
Where collider searches for resonant invisible particles loose steam, dark
sectors might leave their trace as virtual effects in precision observables.
Here we explore this option in the framework of Higgs portal models, where a
sector of dark fermions interacts with the standard model through a strong
renormalizable coupling to the Higgs boson. We show that precise measurements
of Higgs-gauge and triple Higgs interactions can probe dark fermions up to the
TeV scale through virtual corrections. Observation prospects at the LHC and
future lepton colliders are discussed for the so-called singlet-doublet model
of Majorana fermions, a generalization of the bino-higgsino scenario in
supersymmetry. We advocate a two-fold search strategy for dark sectors through
direct and indirect observables.Comment: 20 pages, 7 figures, 1 tabl
The monitoring of seismic activity at Nyiragongo volcano through telemetered seismic network Goma Volcano Observatory (Democratic Republic of the Congo)
The eruption, in January 2002, of Mount Nyiragongo in eastern Congo, and the humanitarian disaster that followed in its wake, underlined the critical importance of accurate seismology to predict when such events will take place. Thus, a seismic telemeterd network, with centre in Goma Observatory, was built across Virunga area to help the moniotring of Volcano.
Mount Nyiragongo is a volcano in the Virunga Mountains associated with the Great Rift Valley. The most prominent feature of the Democratic Republic of Congo's geology is the Western Rift Zone (WRZ), which runs through its eastern border regions and neighbouring countries (e.g. Uganda, Rwanda, Burundi, Tanzania) between 28°E to 32°E and 4°N to 12°S. The WRZ extends over a 1600 km arc, including lakes Albert, Eduard, Kivu and Tanganyika, until it joins the eastern branch. The Western Rift Valley of Africa has experienced severe earthquakes and volcanic eruptions in recent historical times. Earthquakes with magnitude >=6 are not frequent, but may cause significant destruction. They occur mostly in DRC and neighbouring countries (e.g. Uganda and Tanzania). In 1991, IAVCEI selected the Nyiragongo volcano as the âAfrican decade volcanoâ for the International Decade of Natural Disaster Reduction (IDNDR) program. Nyiragongo is located about 20 km north of Lake Kivu and 15 km north of Goma, a city of about 500,000 inhabitants. Goma is twinned to Gisenyi in Rwanda, which has a population of about 100,000. Several small villages are also located on the flank of the volcano. Population growth and poor or non-existent planning has led to relatively uncontrolled use of land for building, and the development of sites vulnerable to earthquake and/or volcanic risk.EUROPEAN CENTER FOR GEODYNAMICS AND SEISMOLOGY
Royal Museum for Central Africa, B
National Museum of Nat. History, LUnpublishedLuxembourg1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attiveope
Truncation, validity, uncertainties
The truncation of the standard-model effective field theory, its validity andthe associated uncertainties have been discussed in meetings of the LHC EFT WG.Proposals were made by participants to address these issues. No consensus wasreached and no formal recommendation is therefore put forward at this time.None of the proposals has been approved or validated and further work is neededto establish a prescription. This note aims at summarizing the proposals andpoints of debate.<br
Truncation, validity, uncertainties
The truncation of the standard-model effective field theory, its validity andthe associated uncertainties have been discussed in meetings of the LHC EFT WG.Proposals were made by participants to address these issues. No consensus wasreached and no formal recommendation is therefore put forward at this time.None of the proposals has been approved or validated and further work is neededto establish a prescription. This note aims at summarizing the proposals andpoints of debate.<br
Altered splicing of the BIN1 muscle-specific exon in humans and dogs with highly progressive centronuclear myopathy
Amphiphysin 2, encoded by BIN1, is a key factor for membrane sensing and remodelling in different cell types. Homozygous BIN1 mutations in ubiquitously expressed exons are associated with autosomal recessive centronuclear myopathy (CNM), a mildly progressive muscle disorder typically showing abnormal nuclear centralization on biopsies. In addition, misregulation of BIN1 splicing partially accounts for the muscle defects in myotonic dystrophy (DM). However, the muscle-specific function of amphiphysin 2 and its pathogenicity in both muscle disorders are not well understood. In this study we identified and characterized the first mutation affecting the splicing of the muscle-specific BIN1 exon 11 in a consanguineous family with rapidly progressive and ultimately fatal centronuclear myopathy. In parallel, we discovered a mutation in the same BIN1 exon 11 acceptor splice site as the genetic cause of the canine Inherited Myopathy of Great Danes (IMGD). Analysis of RNA from patient muscle demonstrated complete skipping of exon 11 and BIN1 constructs without exon 11 were unable to promote membrane tubulation in differentiated myotubes. Comparative immunofluorescence and ultrastructural analyses of patient and canine biopsies revealed common structural defects, emphasizing the importance of amphiphysin 2 in membrane remodelling and maintenance of the skeletal muscle triad. Our data demonstrate that the alteration of the muscle-specific function of amphiphysin 2 is a common pathomechanism for centronuclear myopathy, myotonic dystrophy, and IMGD. The IMGD dog is the first faithful model for human BIN1-related CNM and represents a mammalian model available for preclinical trials of potential therapies
Franchising as a Strategy for Combining Small and Large Group Advantages (Logics) in Social Entrepreneurship:A Hayekian Perspective
This article develops a Hayekian perspective on social franchising that distinguishes between the end-connected logic of the small group and the rule-connected logic of the big group. Our key claim is that mission-driven social entrepreneurs often draw on the small-group logic when starting their social ventures and then face difficulties when the process of scaling shifts their operations toward a big-group logic. In this situation, social franchising offers a strategy to replicate the small group despite systemwide scaling, to mobilize decentrally accessible social capital, and to reduce agency costs through mechanisms of self-selection and self-monitoring. By employing a Hayekian perspective, we are thus able to offer an explanation as to why social franchising is a suitable scaling strategy for some social entrepreneurship organizations and not for others. We illustrate our work using the Ashoka Fellow Wellcome
- âŠ