The refugial speciation model, or ‘species pump’, is widely accepted in the context of tropical biogeography and has been advocated as an explanation for present species distributions in tropical Western and Central Africa. In order to test this hypothesis, a phylogeny of the cryptic arachnid order Ricinulei, based on four nuclear and mitochondrial DNA markers, was inferred. This ancient clade of litter-dwelling arthropods, endemic to the primary forests of Western and Central Africa and the Neotropics, might provide insights into the mode and tempo of evolution in Africa. Twenty- six African ricinuleid specimens were sampled from eight countries spanning the distribution of Ricinulei on the continent, and analysed together with Neotropical samples plus other arachnid outgroups. The phy- logenetic and molecular dating results suggest that Ricinulei diversified in association with the fragmentation of Gondwana. The early diversification of Ricinoides in Western and Central Africa around 88 (+33) Ma fits old palaeogeographical events better than recent climatic fluctuations. Unlike most recent molecular studies, these results agree with fossil evidence, suggesting that refugia may have acted as ‘museums’ conserving ancient diversity rather than as engines generating diversity during successive episodes of climatic fluctuation in Africa.
For-profit, or proprietary, colleges are the fastest-growing postsecondary schools in the nation,
enrolling a disproportionately high share of disadvantaged and minority students and those
ill-prepared for college. Because these schools, many of them big national chains, derive most
of their revenue from taxpayer-funded student financial aid, they are of interest to policy makers not only for the role they play in the higher education spectrum but also for the value they
provide their students. In this article, David Deming, Claudia Goldin, and Lawrence Katz look
at the students who attend for-profits, the reasons they choose these schools, and student outcomes on a number of broad measures and draw several conclusions.
First, the authors write, the evidence shows that public community colleges may provide an
equal or better education at lower cost than for-profits. But budget pressures mean that community colleges and other nonselective public institutions may not be able to meet the demand
for higher education. Some students unable to get into desired courses and programs at public
institutions may face only two alternatives: attendance at a for-profit or no postsecondary education at all.
Second, for-profits appear to be at their best with well-defined programs of short duration that
prepare students for a specific occupation. But for-profit completion rates, default rates, and
labor market outcomes for students seeking associate’s or higher degrees compare unfavorably
with those of public postsecondary institutions. In principle, taxpayer investment in student
aid should be accompanied by scrutiny concerning whether students complete their course of
study and subsequently earn enough to justify the investment and pay back their student loans.
Designing appropriate regulations to help students navigate the market for higher education has
proven to be a challenge because of the great variation in student goals and types of programs.
Ensuring that potential students have complete and objective information about the costs and
expected benefits of for-profit programs could improve postsecondary education opportunities
for disadvantaged students and counter aggressive and potentially misleading recruitment practices at for-profit colleges, the authors write.
Both contemporary witnesses and present-day historians point to the construction of railroads across Manchuria and Inner Mongolia as marking the end of an older order on the Eurasian steppe. The railroad may have disrupted a perceived balance between nomads and settlers along this “Inner Asian Frontier,” and in so doing, integrated the region into the global market economy, but it was the airplane that transformed spatial perception as a new technology of rule during the Japanese occupation. This talk examines how the experience of flight and, correspondingly, aerial perspective led to the formation of a new frontier space in Inner Asia. Taken within a larger context of British bombardment of Arabia and French surveys in Mali and Vietnam, this presentation reveals Japanese anxieties over the seeming vastness of space as the empire sought to expand control over the continent. In an era when national boundaries of airspace remained uncertain in Inner Asia, however, flying planes and building airports often resulted in contested sovereignty over the skies, and one that complicates the nature of informal rule and territoriality for the Japanese empire. If the view of the horizon from a train corresponds to the panorama, as Wolfgang Schivelbusch argues, then the view from an airplane—in eliminating that horizon—corresponds to the map. Such cartographic depictions of an aerial Inner Asia appear in the travelogues of Murata Shirō (?—1945) and Imanishi Kinji (1902-1992) among other intellectuals who experienced flight. Indeed the aerial perspective led to an unprecedented precision in measuring and mapping terrain, as conducted by the photography bureau of Manchukuo National Airways (Manshūkoku kōkū kabushiki kaisha) from the early 1930s. This technology delineated space in new calculative regimes beyond earlier methods of triangulation from the ground. While the resulting maps tended to circulate among military and corporate circles, the aerial perspective did not necessarily produce a privileged view for a select few. Architects and archaeologists, for example, co-opted aerial surveys for their own projects. This view from above, moreover, filtered into literature for mass consumption, from bird’s-eye photographs in tourist publications to technical glossaries in Mongolian-language newspapers, even as their audiences came under increased threat of aerial bombardment during the war.
Anti-tumor necrosis factor alpha (anti-TNF) biologic therapy is a widely used treatment for rheumatoid arthritis (RA). It is unknown why some RA patients fail to respond adequately to anti-TNF therapy, which limits the development of clinical biomarkers to predict response or new drugs to target refractory cases. To understand the biological basis of response to anti-TNF therapy, we conducted a genome-wide association study (GWAS) meta-analysis of more than 2 million common variants in 2,706 RA patients from 13 different collections. Patients were treated with one of three anti-TNF medications: etanercept (n = 733), infliximab (n = 894), or adalimumab (n = 1,071). We identified a SNP (rs6427528) at the 1q23 locus that was associated with change in disease activity score (ΔDAS) in the etanercept subset of patients (P = 8×10(-8)), but not in the infliximab or adalimumab subsets (P>0.05). The SNP is predicted to disrupt transcription factor binding site motifs in the 3' UTR of an immune-related gene, CD84, and the allele associated with better response to etanercept was associated with higher CD84 gene expression in peripheral blood mononuclear cells (P = 1×10(-11) in 228 non-RA patients and P = 0.004 in 132 RA patients). Consistent with the genetic findings, higher CD84 gene expression correlated with lower cross-sectional DAS (P = 0.02, n = 210) and showed a non-significant trend for better ΔDAS in a subset of RA patients with gene expression data (n = 31, etanercept-treated). A small, multi-ethnic replication showed a non-significant trend towards an association among etanercept-treated RA patients of Portuguese ancestry (n = 139, P = 0.4), but no association among patients of Japanese ancestry (n = 151, P = 0.8). Our study demonstrates that an allele associated with response to etanercept therapy is also associated with CD84 gene expression, and further that CD84 expression correlates with disease activity. These findings support a model in which CD84 genotypes and/or expression may serve as a useful biomarker for response to etanercept treatment in RA patients of European ancestry.
Since the end of the Pleistocene, the three-spined stickleback (Gasterosteus aculeatus) has repeatedly colonized and adapted to various freshwater habitats probably originating from ancestral marine populations. Standing genetic variation and the underlying genomic architecture both have been speculated to contribute to recent adaptive radiations of sticklebacks. Here, we expand on the current genomic resources of this fish by providing extensive genome-wide variation data from six individuals from a marine (North Sea) stickleback population. Using next-generation sequencing and a combination of paired-end and mate-pair libraries, we detected a wide size range of genetic variation. Among the six individuals, we found more than 7% of the genome is polymorphic, consisting of 2 599 111 SNPs, 233 464 indels and structural variation (SV) (>50 bp) such as 1054 copy-number variable regions (deletions and duplications) and 48 inversions. Many of these polymorphisms affect gene and coding sequences. Based on SNP diversity, we determined outlier regions concordant with signatures expected under adaptive evolution. As some of these outliers overlap with pronounced regions of copy-number variation, we propose the consideration of such SV when analysing SNP data from re-sequencing approaches. We further discuss the value of this resource on genome-wide variation for further investigation upon the relative contribution of standing variation on the parallel evolution of sticklebacks and the importance of the genomic architecture in adaptive radiation.
Learning functional brain connectivity is essential to the understanding of neurodegenerative diseases. In this paper, we introduce a novel graph regression model (GRM) which regards the imaging data as signals defined on a graph and optimizes the fitness between the graph and the data, with a sparsity level regularization. The proposed framework features a nice interpretation in terms of low-pass signals on graphs, and is more generic compared with previous statistical models. Results based on the data illustrates that our approach can obtain a very close reconstruction of the true network. We then apply the GRM to learn the brain connectivity of Alzheimer’s disease (AD). Evaluations performed upon PET imaging data of 30 AD patients demonstrate that the connectivity patterns discovered are easy to interpret and consistent with known pathology.