42 research outputs found
The Simons Observatory: Large-Scale Characterization of 90/150 GHz TES Detector Modules
The Simons Observatory (SO) is a cosmic microwave background instrumentation
suite being deployed in the Atacama Desert in northern Chile. The telescopes
within SO use three types of dichroic transition-edge sensor (TES) detector
arrays, with the 90 and 150 GHz Mid-Frequency (MF) arrays containing 65% of the
approximately 68,000 detectors in the first phase of SO. All of the 26 required
MF detector arrays have now been fabricated, packaged into detector modules,
and tested in laboratory cryostats. Across all modules, we find an average
operable detector yield of 84% and median saturation powers of (2.8, 8.0) pW
with interquartile ranges of (1, 2) pW at (90, 150) GHz, respectively, falling
within their targeted ranges. We measure TES normal resistances and
superconducting transition temperatures on each detector wafer to be uniform
within 3%, with overall central values of 7.5 mohm and 165 mK, respectively.
Results on time constants, optical efficiency, and noise performance are also
presented and are consistent with achieving instrument sensitivity forecasts.Comment: 8 pages, 3 figures. Proceedings of the 20th International Conference
on Low Temperature Detectors (LTD20). Accepted to JLT
The Simons Observatory Large Aperture Telescope Receiver
The Simons Observatory (SO) Large Aperture Telescope Receiver (LATR) will be
coupled to the Large Aperture Telescope located at an elevation of 5,200 m on
Cerro Toco in Chile. The resulting instrument will produce arcminute-resolution
millimeter-wave maps of half the sky with unprecedented precision. The LATR is
the largest cryogenic millimeter-wave camera built to date with a diameter of
2.4 m and a length of 2.6 m. It cools 1200 kg of material to 4 K and 200 kg to
100 mk, the operating temperature of the bolometric detectors with bands
centered around 27, 39, 93, 145, 225, and 280 GHz. Ultimately, the LATR will
accommodate 13 40 cm diameter optics tubes, each with three detector wafers and
a total of 62,000 detectors. The LATR design must simultaneously maintain the
optical alignment of the system, control stray light, provide cryogenic
isolation, limit thermal gradients, and minimize the time to cool the system
from room temperature to 100 mK. The interplay between these competing factors
poses unique challenges. We discuss the trade studies involved with the design,
the final optimization, the construction, and ultimate performance of the
system
The Simons Observatory microwave SQUID multiplexing detector module design
Advances in cosmic microwave background (CMB) science depend on increasing
the number of sensitive detectors observing the sky. New instruments deploy
large arrays of superconducting transition-edge sensor (TES) bolometers tiled
densely into ever larger focal planes. High multiplexing factors reduce the
thermal loading on the cryogenic receivers and simplify their design. We
present the design of focal-plane modules with an order of magnitude higher
multiplexing factor than has previously been achieved with TES bolometers. We
focus on the novel cold readout component, which employs microwave SQUID
multiplexing (mux). Simons Observatory will use 49 modules containing
60,000 bolometers to make exquisitely sensitive measurements of the CMB. We
validate the focal-plane module design, presenting measurements of the readout
component with and without a prototype detector array of 1728
polarization-sensitive bolometers coupled to feedhorns. The readout component
achieves a yield and a 910 multiplexing factor. The median white noise
of each readout channel is 65 . This impacts the
projected SO mapping speed by , which is less than is assumed in the
sensitivity projections. The results validate the full functionality of the
module. We discuss the measured performance in the context of SO science
requirements, which are exceeded.Comment: Accepted to The Astrophysical Journa
Finishing the euchromatic sequence of the human genome
The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers âŒ99% of the euchromatic genome and is accurate to an error rate of âŒ1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead
Genomic investigations of unexplained acute hepatitis in children
Since its first identification in Scotland, over 1,000 cases of unexplained paediatric hepatitis in children have been reported worldwide, including 278 cases in the UK1. Here we report an investigation of 38 cases, 66 age-matched immunocompetent controls and 21 immunocompromised comparator participants, using a combination of genomic, transcriptomic, proteomic and immunohistochemical methods. We detected high levels of adeno-associated virus 2 (AAV2) DNA in the liver, blood, plasma or stool from 27 of 28 cases. We found low levels of adenovirus (HAdV) and human herpesvirus 6B (HHV-6B) in 23 of 31 and 16 of 23, respectively, of the cases tested. By contrast, AAV2 was infrequently detected and at low titre in the blood or the liver from control children with HAdV, even when profoundly immunosuppressed. AAV2, HAdV and HHV-6 phylogeny excluded the emergence of novel strains in cases. Histological analyses of explanted livers showed enrichment for T cells and B lineage cells. Proteomic comparison of liver tissue from cases and healthy controls identified increased expression of HLA class 2, immunoglobulin variable regions and complement proteins. HAdV and AAV2 proteins were not detected in the livers. Instead, we identified AAV2 DNA complexes reflecting both HAdV-mediated and HHV-6B-mediated replication. We hypothesize that high levels of abnormal AAV2 replication products aided by HAdV and, in severe cases, HHV-6B may have triggered immune-mediated hepatic disease in genetically and immunologically predisposed children
DoD Is Ready to Accept Transgender Applicants
On December 6, the Department of Justice submitted a written Declaration claiming that Pentagon compliance with a Courtâs order to allow transgender candidates to apply for enlistment as of January 1 would âimpose extraordinary burdensâ on a military that âwould not be adequately and properly prepared to begin processing transgender applicants.â The Declaration, however, rewrites the history of transgender military policy and distorts the evidence, disregarding that the Courtâs order did not create new military policy, but only directed the military to return to its own policy on transgender enlistment as defined by the current Secretary of Defense. Three former Service Secretaries and one former Acting Under Secretary of Defense for Personnel and Readiness have confirmed that the military had already completed many of the necessary preparations for the lifting of the enlistment ban by the time of the Presidential transition in January, 2017. The Declarationâs assertion that implementing the Courtâs order will impose âextraordinary burdensâ because the military âwould not be adequately and properly preparedâ is incorrect. The Declarationâs assertion that transgender applicants for military service are uniquely complicated and difficult to evaluate is incorrect. The Declarationâs assertions that recruiters will not understand government identification documents that reflect changes in gender, and are not prepared to obtain supporting medical documents, are incorrect. The Declarationâs assertion that the Courtâs order will result in transgender applicants not receiving âthe appropriate medical and administrative accession screeningâ is incorrect. The Declarationâs assertion that âkey personnelâ have ârotatedâ into different duties, therefore setting back the pace of implementation and requiring more time, is not a reason for delay
t(X;14)(p11;q32) in MALT lymphoma involving GPR34 reveals a role for GPR34 in tumor cell growth
Genetic aberrations, including trisomies 3 and 18, and well-defined IGH translocations, have been described in marginal zone lymphomas (MZLs); however, these known genetic events are present in only a subset of cases. Here, we report the cloning of an IGH translocation partner on chromosome X, t(X;14)(p11.4;q32) that deregulates expression of an poorly characterized orphan G-proteinâcoupled receptor, GPR34. Elevated GPR34 gene expression was detected independent of the translocation in multiple subtypes of non-Hodgkin lymphoma and distinguished a unique molecular subtype of MZL. Increased expression of GPR34 was also detected in tissue from brain tumors and surface expression of GPR34 was detected on human MZL tumor cells and normal immune cells. Overexpression of GPR34 in lymphoma and HeLa cells resulted in phosphorylation of ERK, PKC, and CREB; induced CRE, AP1, and NF-ÎșBâmediated gene transcription; and increased cell proliferation. In summary, these results are the first to identify a role for a GPR34 in lymphoma cell growth, provide insight into GPR34-mediated signaling, identify a genetically unique subset of MZLs that express high levels of GPR34, and suggest that MEK inhibitors may be useful for treatment of GPR34-expressing tumors