Order and coherence in the fate map of the zebrafish nervous system

The zebrafish is an excellent vertebrate model for the study of the cellular interactions underlying the patterning and the morphogenesis of the nervous system. Here, we report regional fate maps of the zebrafish anterior nervous system at two key stages of neural development: the beginning (6 hours) and the end (10 hours) of gastrulation. Early in gastrulation, we find that the presumptive neurectoderm displays a predictable organization that reflects the future anteroposterior and dorsoventral order of the central nervous system. The precursors of the major brain subdivisions (forebrain, midbrain, hindbrain, neural retina) occupy discernible, though overlapping, domains within the dorsal blastoderm at 6 hours. As gastrulation proceeds, these domains are rearranged such that the basic order of the neural tube is evident at 10 hours. Furthermore, the anteroposterior and dorsoventral order of the progenitors is refined and becomes aligned with the primary axes of the embryo. Time-lapse video microscopy shows that the rearrangement of blastoderm cells during gastrulation is highly ordered. Cells near the dorsal midline at 6 hours, primarily forebrain progenitors, display anterior-directed migration. Cells more laterally positioned, corresponding to midbrain and hindbrain progenitors, converge at the midline prior to anteriorward migration. These results demonstrate a predictable order in the presumptive neurectoderm, suggesting that patterning interactions may be well underway by early gastrulation. The fate maps provide the basis for further analyses of the specification, induction and patterning of the anterior nervous system, as well as for the interpretation of mutant phenotypes and gene-expression patterns

SEARS: Space Efficient And Reliable Storage System in the Cloud

Today's cloud storage services must offer storage reliability and fast data retrieval for large amount of data without sacrificing storage cost. We present SEARS, a cloud-based storage system which integrates erasure coding and data deduplication to support efficient and reliable data storage with fast user response time. With proper association of data to storage server clusters, SEARS provides flexible mixing of different configurations, suitable for real-time and archival applications. Our prototype implementation of SEARS over Amazon EC2 shows that it outperforms existing storage systems in storage efficiency and file retrieval time. For 3 MB files, SEARS delivers retrieval time of $2.5$ s compared to $7$ s with existing systems.Comment: 4 pages, IEEE LCN 201

The synthesis and characterization of compounds with framework elements of contrasting reactivities {B, Si}-{P, As}

The reactivity difference between boron or silicon with phosphorus or arsenic creates challenges in synthesis. Synthesizing ternary compounds increases the level of complexity. The syntheses of new multinary compounds consisting of covalent bonds between these elements of drastically different reactivities have been investigated, and the resulting products were characterized. Between silicon and arsenic, a completely new set of compounds in the Mg-Si-As system were discovered, as well as a highly versatile family of Cs0.16MxSi1-xAs2 (M = Cu, Zn, Ga). Compounds in the Mg-Si-As system seem to show a preference with crystalizing in non-centrosymmetric space groups, which is uncommon through solid state synthesis methods. MgSiAs2 has been studied theoretically for years, but had never been realized experimentally. With its now successful synthesis, MgSiAs2 displays a good balance of second harmonic generation response and laser damage threshold. Mg3Si6As8 has a space group of P4332 (No. 212), which is in the one Laue class, 432, that does not allow second harmonic generation, but electronic structure calculations suggest the compound may be used as a thermoelectric material upon doping. Layered Cs0.16MxSi1-xAs2 (M = Cu, Zn, Ga) compounds show potential as a thermoelectric material due to the anisotropic 2D crystal structure. Their ability to substitute various metals into the layered framework without altering the crystal structure introduces the option of tuning the material. Using BI3 as a boron source was investigated for the reaction with phosphorus and various metals. This method allowed BP to be synthesized very quickly at moderate temperatures and with low contamination compared to flux reactions or the direct reaction of boron and phosphorus. These advantages transferred to the synthesis of metal borides, and Ni2CoB was produced when starting with a NiCo alloy. To explore the formation of metal boron phosphide compounds containing covalent B-P bonds, solid state metathesis between Na3BP2 and metal halides, mainly CuCl, was performed. In situ powder X-ray diffraction experiments were utilized in conjunction with lab experiments to gain insight on a new “Na-Cu-B-P” compound. Surprisingly, a new non-centrosymmetric Na2BP2 compound with the space group of Pna21 (No. 33) was discovered in a reaction of leaching Na from Na3BP2 using CuI and a CsI/NaI flux

With Federal Moratorium Expiring, 15 Million People at Risk of Eviction

Nationwide, renters are recovering from an unprecedented economic crisis. With vaccines widely accessible, employment rising, and federal and state benefits available to millions of people, many of the over 100 million people living in rental housing are making a gradual recovery. Despite this progress, a meaningful percentage of renters are on the precipice of eviction, displacement, and homelessness. More than 15 million people live in households that are currently behind on their rental payments (7.4 million adults, 6.5 million households), which places them at legal risk of eviction. According to one estimate, these households collectively owe more than $20 billion to their landlords. On a per tenant basis, average debt owed to landlords exceeds$3,000, with significant variation based on time away from work, family needs, and other factors.When the Centers for Disease Control and Prevention (CDC) eviction moratorium ends on July 31st, these renters may face eviction, civil lawsuits for unpaid rent, and aggressive debt collection—crises that will continue to cause harm years into the future. Nearly 50% of those who are behind on rent anticipate that they will be evicted in the next two months. The threat of eviction is particularly acute for renters of color. Currently, 22% of Black renters and 17% of Latinx renters are in debt to their landlords, compared to 15% overall and 11% of White renters. Rental debt is also challenging for renters with children, with 19% unable to make payments.This report highlights the current number of people at risk of eviction as the federal moratorium expires, how we got here, and policies states can implement to help prevent a wave of evictions from cascading into long-term health and financial crises for millions of households

Ancient undersea middens offer clues about life before rising seas engulfed the coast. Now we have a better way to study them

The world’s oceans hold their secrets close, including clues about how people lived tens of thousands of years ago. For a large portion of humanity’s existence, sea levels were significantly lower (up to 130 metres) than they are today, exposing millions of square kilometres of land. And the archaeological record is clear: people in the past lived on these coastal plains before the land slipped beneath the waves. Archaeology already tells us these drowned landscapes played significant roles in human history. Major events such as human migrations across the globe and the invention of maritime technology took place along these now-drowned shorelines. But these sites can be hard to find

Critical Role of an MHC Class I-Like/Innate-Like T Cell Immune Surveillance System in Host Defense against Ranavirus (Frog Virus 3) Infection

Source at https://doi.org/10.3390/v11040330. Besides the central role of classical Major Histocompatibility Complex (MHC) class Ia-restricted conventional Cluster of Differentiation 8 (CD8) T cells in antiviral host immune response, the amphibian Xenopus laevis critically rely on MHC class I-like (mhc1b10.1.L or XNC10)-restricted innate-like (i)T cells (iVα6 T cells) to control infection by the ranavirus Frog virus 3 (FV3). To complement and extend our previous reverse genetic studies showing that iVα6 T cells are required for tadpole survival, as well as for timely and effective adult viral clearance, we examined the conditions and kinetics of iVα6 T cell response against FV3. Using a FV3 knock-out (KO) growth-defective mutant, we found that upregulation of the XNC10 restricting class I-like gene and the rapid recruitment of iVα6 T cells depend on detectable viral replication and productive FV3 infection. In addition, by in vivo depletion with XNC10 tetramers, we demonstrated the direct antiviral effector function of iVα6 T cells. Notably, the transitory iVα6 T cell defect delayed innate interferon and cytokine gene response, resulting in long-lasting negative inability to control FV3 infection. These findings suggest that in Xenopus and likely other amphibians, an immune surveillance system based on the early activation of iT cells by non-polymorphic MHC class-I like molecules is important for efficient antiviral immune response

Beneath the Top End: a regional assessment of submerged archaeological potential in the Northern Territory, Australia

Regional-scale assessments have proven to be invaluable frameworks for research, public engagement and management of submerged archaeological landscapes. Regional-scale approaches have been implemented internationally through a variety of academic or strategic studies. Such studies represent a much-needed next step towards subregional and site-level prospection to support management, engagement and mitigation of the impacts of offshore development. However, these regional studies are largely absent in Australia. In this article, we build on the recent discovery of submerged archaeological sites in Western Australia and produce a novel regional-scale assessment of submerged archaeological and cultural landscape potential in the coastal and island regions of the Northern Territory. This area is of special significance in the peopling of Australia, containing some of the oldest dated archaeological evidence. We collate and synthesise regional data related to sea-level change, ethnography (e.g. oral traditions), geomorphology, and archaeology, also taking account of logistics and existing data availability to identify prospective areas for further study. We highlight the need for a coordinated national program of regional baseline studies to address a legacy of under-representation of submerged landscapes and provide vital baseline data for a wide spectrum of stakeholders, including researchers, policy makers, environmental and heritage managers, developers and Traditional Owners

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Racism, Reform, Revolution? The Segrenomics of American Education. A Book Review of \u3cem\u3eCutting School: Privatization, Segregation, and the End of Public Education\u3c/em\u3e

A review of the book Cutting School: Privatization, Segregation, and the End of Public Education, by Noliwe Rooks (The New Press, 2017)