633 research outputs found
Scaling Law for the Cosmological Constant from Quantum Cosmology with Seven Extra Dimensions
According to a model of quantum cosmology the maximum number of degrees of
freedom allowed in our three dimensions was determined by the size of seven
extra dimensions in an initial excited state before inflation. The size of the
extra dimensions can be inferred from a simple scheme for unifying the strong
force and gravity. Coupled with the Bekenstein-Hawking entropy bound, these
considerations lead to a scaling law for the cosmological constant that has
been proposed independently by several authors.Comment: matches published version in IJT
Algorithms to automatically quantify the geometric similarity of anatomical surfaces
We describe new approaches for distances between pairs of 2-dimensional
surfaces (embedded in 3-dimensional space) that use local structures and global
information contained in inter-structure geometric relationships. We present
algorithms to automatically determine these distances as well as geometric
correspondences. This is motivated by the aspiration of students of natural
science to understand the continuity of form that unites the diversity of life.
At present, scientists using physical traits to study evolutionary
relationships among living and extinct animals analyze data extracted from
carefully defined anatomical correspondence points (landmarks). Identifying and
recording these landmarks is time consuming and can be done accurately only by
trained morphologists. This renders these studies inaccessible to
non-morphologists, and causes phenomics to lag behind genomics in elucidating
evolutionary patterns. Unlike other algorithms presented for morphological
correspondences our approach does not require any preliminary marking of
special features or landmarks by the user. It also differs from other seminal
work in computational geometry in that our algorithms are polynomial in nature
and thus faster, making pairwise comparisons feasible for significantly larger
numbers of digitized surfaces. We illustrate our approach using three datasets
representing teeth and different bones of primates and humans, and show that it
leads to highly accurate results.Comment: Changes with respect to v1, v2: an Erratum was added, correcting the
references for one of the three datasets. Note that the datasets and code for
this paper can be obtained from the Data Conservancy (see Download column on
v1, v2
Erythrocyte complement receptor 1 (CR1) expression level is not associated with polymorphisms in the promoter or 3' untranslated regions of the CR1 gene
Complement receptor 1 (CR1) expression level on erythrocytes is genetically determined and is associated with high (H) and low (L) expression alleles identified by a HindIII restriction fragment-length polymorphism (RFLP) in intron 27 of the CR1 gene. The L allele confers protection against severe malaria in Papua New Guinea, probably because erythrocytes with low CR1 expression, are less able to form pathogenic rosettes with Plasmodium falciparum-infected erythrocytes. Despite the biological importance of erythrocyte CR1, the genetic mutation controlling CR1 expression level remains unknown. We investigated the possibility that mutations in the upstream or 3′ untranslated regions of the CR1 gene could control erythrocyte CR1 level. We identified several novel polymorphisms; however, the mutations did not segregate with erythrocyte CR1 expression level or the H and L alleles. Therefore, high and low erythrocyte CR1 levels cannot be explained by polymorphisms in transcriptional control elements in the upstream or 3′ untranslated regions of the CR1 gene
Molecular Beams
Contains reports on five research projects.Lincoln Laboratory (Purchase Order DDL B-00306)United States Air Force (Contract AF19(604)-7400)United States NavyUnited States Arm
RESOLUTION‐RETRIEVING SOURCE‐EFFECT COMPENSATION IN HOLOGRAPHY WITH EXTENDED SOURCES
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69575/2/APPLAB-7-6-178-1.pd
Fourier-transform spectroscopy using holographic imaging without computing and with stationary interferometers
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/32013/1/0000055.pd
The thermodynamic evolution of the cosmological event horizon
By manipulating the integral expression for the proper radius of the
cosmological event horizon (CEH) in a Friedmann-Robertson-Walker (FRW)
universe, we obtain an analytical expression for the change \dd R_e in
response to a uniform fluctuation \dd\rho in the average cosmic background
density . We stipulate that the fluctuation arises within a vanishing
interval of proper time, during which the CEH is approximately stationary, and
evolves subsequently such that \dd\rho/\rho is constant. The respective
variations 2\pi R_e \dd R_e and \dd E_e in the horizon entropy and
enclosed energy should be therefore related through the cosmological
Clausius relation. In that manner we find that the temperature of the CEH
at an arbitrary time in a flat FRW universe is , which recovers
asymptotically the usual static de Sitter temperature. Furthermore, it is
proven that during radiation-dominance and in late times the CEH conforms to
the fully dynamical First Law T_e \drv S_e = P\drv V_e - \drv E_e, where
is the enclosed volume and is the average cosmic pressure.Comment: 6 page
Comprehensive and user-analytics-friendly cancer patient database for physicians and researchers
Nuanced cancer patient care is needed, as the development and clinical course
of cancer is multifactorial with influences from the general health status of
the patient, germline and neoplastic mutations, co-morbidities, and
environment. To effectively tailor an individualized treatment to each patient,
such multifactorial data must be presented to providers in an easy-to-access
and easy-to-analyze fashion. To address the need, a relational database has
been developed integrating status of cancer-critical gene mutations, serum
galectin profiles, serum and tumor glycomic profiles, with clinical,
demographic, and lifestyle data points of individual cancer patients. The
database, as a backend, provides physicians and researchers with a single,
easily accessible repository of cancer profiling data to aid-in and enhance
individualized treatment. Our interactive database allows care providers to
amalgamate cohorts from these groups to find correlations between different
data types with the possibility of finding "molecular signatures" based upon a
combination of genetic mutations, galectin serum levels, glycan compositions,
and patient clinical data and lifestyle choices. Our project provides a
framework for an integrated, interactive, and growing database to analyze
molecular and clinical patterns across cancer stages and subtypes and provides
opportunities for increased diagnostic and prognostic power.Comment: 7 pages, 12 figures, peer reviewed and accepted in "International
Conference on Computational Science and Computational Intelligence (CSCI 22)
A stem-cell-derived platform enables complete Cryptosporidium development in vitro and genetic tractability
Despite being a frequent cause of severe diarrheal disease in infants and an opportunistic infection in immunocompromised patients, Cryptosporidium research has lagged due to a lack of facile experimental methods. Here, we describe a platform for complete life cycle development and long-term growth of C. parvum in vitro using air-liquid interface (ALI) cultures derived from intestinal epithelial stem cells. Transcriptomic profiling revealed that differentiating epithelial cells grown under ALI conditions undergo profound changes in metabolism and development that enable completion of the parasite life cycle in vitro. ALI cultures support parasite expansion \u3e 100-fold and generate viable oocysts that are transmissible in vitro and to mice, causing infection and animal death. Transgenic parasite lines created using CRISPR/Cas9 were used to complete a genetic cross in vitro, demonstrating Mendelian segregation of chromosomes during meiosis. ALI culture provides an accessible model that will enable innovative studies into Cryptosporidium biology and host interactions
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