845 research outputs found
A CES APPROACH TO THE MEASUREMENT OF INDUCED FACTOR AUGMENTATION: A TEST FOR JAPAN
International Development,
INDUCED INNOVATION: A CES-TYPE META-PRODUCTION FUNCTION
Research and Development/Tech Change/Emerging Technologies,
Livestock products in the Third World: past trends and projections to 1990 and 2000
Meat industry and trade Developing countries Statistics., Dairy products industry Developing countries Statistics., Meat industry and trade Developing countries Forecasting Statistical methods., Dairy products industry Developing countries Forecasting Statistical methods.,
Encouraging Learning with the Aid of Virtual Money
Motivation has been a key factor to meeting any goal. Motivation involves providing a reason for someone to act a certain way. It involves an incentive to meet a certain end, either driven by intrinsic or extrinsic motivation. Students today have been afflicted with a loss of motivation. The loss of motivation is mainly caused by a lack of faith in oneÂ’s ability, laziness, fear of failure, stress, and other impediments. We have found that educational software is a growing medium for teaching students. Our group carried out an experiment to observe the effects our designed monetary system in an academic environment. We have determined that maintaining motivation can be accomplished by providing incentives to students
Genetic study of congenital bile-duct dilatation identifies de novo and inherited variants in functionally related genes
Background:
Congenital dilatation of the bile-duct (CDD) is a rare, mostly sporadic, disorder that results in bile retention with severe associated complications. CDD affects mainly Asians. To our knowledge, no genetic study has ever been conducted.
Methods:
We aim to identify genetic risk factors by a “trio-based” exome-sequencing approach, whereby 31 CDD probands and their unaffected parents were exome-sequenced. Seven-hundred controls from the local population were used to detect gene-sets significantly enriched with rare variants in CDD patients.
Results:
Twenty-one predicted damaging de novo variants (DNVs; 4 protein truncating and 17 missense) were identified in several evolutionarily constrained genes (p < 0.01). Six genes carrying DNVs were associated with human developmental disorders involving epithelial, connective or bone morphologies (PXDN, RTEL1, ANKRD11, MAP2K1, CYLD, ACAN) and four linked with cholangio- and hepatocellular carcinomas (PIK3CA, TLN1 CYLD, MAP2K1). Importantly, CDD patients have an excess of DNVs in cancer-related genes (p < 0.025). Thirteen genes were recurrently mutated at different sites, forming compound heterozygotes or functionally related complexes within patients.
Conclusions:
Our data supports a strong genetic basis for CDD and show that CDD is not only genetically heterogeneous but also non-monogenic, requiring mutations in more than one genes for the disease to develop. The data is consistent with the rarity and sporadic presentation of CDD
On-chip indistinguishable photons using III-V nanowire/SiN hybrid integration
We demonstrate on-chip generation of indistinguishable photons based on a
nanowire quantum dot. From a growth substrate containing arrays of
positioned-controlled single dot nanowires, we select a single nanowire which
is placed on a SiN waveguide fabricated on a Si-based chip. Coupling of the
quantum dot emission to the SiN waveguide is via the evanescent mode in the
tapered nanowire. Post-selected two-photon interference visibilities using
continuous wave excitation above-band and into a p-shell of the dot were 100%,
consistent with a single photon source having negligible multi-photon emission
probability. Visibilities over the entire photon wavepacket, measured using
pulsed excitation, were reduced by a factor of 5 when exciting quasi-resonantly
and by a factor of 10 for above-band excitation. The role of excitation timing
jitter, spectral diffusion and pure dephasing in limiting visibilities over the
temporal extent of the photon is investigated using additional measurements of
the coherence and linewidth of the emitted photons
Comparative transcriptional profiling of the limbal epithelial crypt demonstrates its putative stem cell niche characteristics
<p>Abstract</p> <p>Background</p> <p>The Limbal epithelial crypt (LEC) is a solid cord of cells, approximately 120 microns long. It arises from the undersurface of interpalisade rete ridges of the limbal palisades of Vogt and extends deeper into the limbal stroma parallel or perpendicular to the palisade. There are up to 6 or 7 such LEC, variably distributed along the limbus in each human eye.</p> <p>Morphological and immunohistochemical studies on the limbal epithelial crypt (LEC) have demonstrated the presence of limbal stem cells in this region. The purpose of this microarray study was to characterise the transcriptional profile of the LEC and compare with other ocular surface epithelial regions to support our hypothesis that LEC preferentially harbours stem cells (SC).</p> <p>Results</p> <p>LEC was found to be enriched for SC related Gene Ontology (GO) terms including those identified in quiescent adult SC, however similar to cornea, limbus had significant GO terms related to proliferating SC, transient amplifying cells (TAC) and differentiated cells (DC). LEC and limbus were metabolically dormant with low protein synthesis and downregulated cell cycling. Cornea had upregulated genes for cell cycling and self renewal such as <it>FZD7, BTG1, CCNG</it>, and <it>STAT3 </it>which were identified from other SC populations. Upregulated gene expression for growth factors, cytokines, WNT, Notch, TGF-Beta pathways involved in cell proliferation and differentiation were noted in cornea. LEC had highest number of expressed sequence tags (ESTs), downregulated and unknown genes, compared to other regions. Genes expressed in LEC such as <it>CDH1, SERPINF1, LEF1, FRZB1</it>, <it>KRT19, SOD2, EGR1 </it>are known to be involved in SC maintenance. Genes of interest, in LEC belonging to the category of cell adhesion molecules, WNT and Notch signalling pathway were validated with real-time PCR and immunofluorescence.</p> <p>Conclusions</p> <p>Our transcriptional profiling study identifies the LEC as a preferential site for limbal SC with some characteristics suggesting that it could function as a 'SC niche' supporting quiescent SC. It also strengthens the evidence for the presence of "transient cells" in the corneal epithelium. These cells are immediate progeny of SC with self-renewal capacity and could be responsible for maintaining epithelial turn over in normal healthy conditions of the ocular surface (OS). The limbus has mixed population of differentiated and undifferentiated cells.</p
- …