13,623 research outputs found
A theoretical estimate for nucleotide sugar demand towards Chinese Hamster Ovary cellular glycosylation
Glycosylation greatly influences the safety and efficacy of many of the highest-selling recombinant therapeutic proteins (rTPs). In order to define optimal cell culture feeding strategies that control rTP glycosylation, it is necessary to know how nucleotide sugars (NSs) are consumed towards host cell and rTP glycosylation. Here, we present a theoretical framework that integrates the reported glycoproteome of CHO cells, the number of N-linked and O-GalNAc glycosylation sites on individual host cell proteins (HCPs), and the carbohydrate content of CHO glycosphingolipids to estimate the demand of NSs towards CHO cell glycosylation. We have identified the most abundant N-linked and O-GalNAc CHO glycoproteins, obtained the weighted frequency of N-linked and O-GalNAc glycosites across the CHO cell proteome, and have derived stoichiometric coefficients for NS consumption towards CHO cell glycosylation. By combining the obtained stoichiometric coefficients with previously reported data for specific growth and productivity of CHO cells, we observe that the demand of NSs towards glycosylation is significant and, thus, is required to better understand the burden of glycosylation on cellular metabolism. The estimated demand of NSs towards CHO cell glycosylation can be used to rationally design feeding strategies that ensure optimal and consistent rTP glycosylation
Determinants of Meats Purchase Behavior by Ethnic Groups
Farmers and food companies need to assess their production and marketing strategies for nurturing business opportunities that will arise from the simultaneous increase in population and income of Hispanics in the United States. Previous studies on demand for meat products have not received much attention on the determinants of meats purchase behavior by Hispanics in relation to other ethnic groups. This study investigates the impact of ethnicity and the determinants of meats purchase behavior in the U.S. by using single Probit equations. The analyzed data comes from the U.S. Consumer Expenditure Survey. The results indicate that ethnicity plays an important role in the purchase behavior of meat products, as well as household size and income.consumer behavior, marketing, food demand, Hispanic food, hispanic food market, Latin foods, comida latina, alimentos, ethnic foods, Agribusiness, Consumer/Household Economics, Demand and Price Analysis, Food Consumption/Nutrition/Food Safety, Industrial Organization, Marketing, D01, D03, D12, L14, L66, M31, M37,
The Effects of Public Debt on Labor Demand in the United States
The relationship between appreciation of the exchange rate and employment is investigated in the period 1980-2008 for the United States. Previous literature has found a negative relationship, studying as channels of transmission the role of exports, substitution of factors of production, terms of trade, openness, and productivity. This study endeavors to shed some light on the role of government debt on determining the level of employment through the exchange rate. The mechanism of transmission is defined. The model is derived from a standard Cobb Douglas production function having government debt affecting the growth of productivity. Exchange rate appreciations and increasing public debt were found to be detrimental to employment.Unemployment rate, government, budget deficit, exchange rate, trade deficit, FDI, Financial Economics, International Development, Labor and Human Capital, Political Economy, Public Economics, F31, J01, E24, E62,
Class-Weighted Convolutional Features for Visual Instance Search
Image retrieval in realistic scenarios targets large dynamic datasets of
unlabeled images. In these cases, training or fine-tuning a model every time
new images are added to the database is neither efficient nor scalable.
Convolutional neural networks trained for image classification over large
datasets have been proven effective feature extractors for image retrieval. The
most successful approaches are based on encoding the activations of
convolutional layers, as they convey the image spatial information. In this
paper, we go beyond this spatial information and propose a local-aware encoding
of convolutional features based on semantic information predicted in the target
image. To this end, we obtain the most discriminative regions of an image using
Class Activation Maps (CAMs). CAMs are based on the knowledge contained in the
network and therefore, our approach, has the additional advantage of not
requiring external information. In addition, we use CAMs to generate object
proposals during an unsupervised re-ranking stage after a first fast search.
Our experiments on two public available datasets for instance retrieval,
Oxford5k and Paris6k, demonstrate the competitiveness of our approach
outperforming the current state-of-the-art when using off-the-shelf models
trained on ImageNet. The source code and model used in this paper are publicly
available at http://imatge-upc.github.io/retrieval-2017-cam/.Comment: To appear in the British Machine Vision Conference (BMVC), September
201
Stellar indices and kinematics in Seyfert 1 nuclei
We present spectra of 6 type 1 Seyfert galaxies, 2 Seyfert 2, a starburst
galaxy and a compact narrow line radiogalaxy, taken in two spectral ranges
centered around the near--IR CaII triplet (CaT) (at ~8600 Angstroms), and the
Mgb stellar feature at 5180 Angstroms. We measured the equivalent width (EWs)
of these features and the Fe52 and Fe53 spectral indices. We found that the
strength of the CaT in type 1 Seyfert galaxies with prominent central point
sources, is larger than what would be expected from the observed strength of
the blue indices. This could be explained by the presence of red supergiants in
the nuclei of Seyfert 1 galaxies. On the other hand, the blue indices of these
galaxies could also be diluted by the strong FeII multiplets that can be seen
in their spectra.
We have also measured the stellar and gas velocity dispersions of the
galaxies in the sample. The stellar velocity dispersions were measured using
both, the Mgb and CaT stellar features. The velocity dispersion of the gas in
the narrow line region (NLR) was measured using the strong emission lines
[OIII] 5007, 4959 and [SIII] 9069. We compare the gas and star velocity
dispersions and find that both magnitudes are correlated in Seyfert galaxies.
Most of the Seyfert 1 we observe have stellar velocity dispersion somehow
greater than that of the gas in the NLR.Comment: To appear in MNRAS, 18 pages, 9 figure
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