693 research outputs found
A Welfare Analysis of Spectrum Allocation Policies
Analysis of spectrum allocation policies in the economics literature focuses on competitive bidding for wireless licenses. Auctions generating high bids, as in Germany and the UK, are identified as "successful," while those producing lower receipts, as in Switzerland and the Netherlands, are deemed "fiascoes." Yet, even full and costless extraction of license rents does not map directly to social welfare, because spectrum policies creating rents impose social costs. For example, rules favoring monopoly market structure predictably increase license values, but reduce welfare. This paper attempts to shift analytical focus to the relationship between spectrum policy (including license auctions) and efficiency in output markets. In cross-country comparisons of performance metrics in mobile telephone service markets, empirical estimates suggest that countries that auction licenses do not achieve lower prices or higher levels of output than other nations. Rather, countries allocating greater bandwidth to licensed operators and achieving more competitive market structures realize demonstrable social welfare benefits. These gains generally dominate efficiencies associated with license sales. Policies to increase auction revenues, such as reservation prices and subsidies for weak bidders, should be evaluated in this light.
What Really Matters in Spectrum Allocation Design
Since initiated in the U.S. in July 1994, auctions have replaced "beauty contests" in the assignment of wireless licenses in many countries. Economists have been involved in constructing the competitive bidding mechanisms chosen, and have devoted considerable analysis to the problems involved. Generally, auction methods have been evaluated according to the receipts generated; social gains resulting from the displacement of activity-distorting taxes has motivated the welfare analysis. Yet, policies widely advocated by economists to intensify license bidding , such as reservation prices or bidding credits for "weak"' bidders , may impose deadweight losses that dominate revenue raising efficiencies. Yet, retail market effects are largely excluded from cost-benefit calculations of rules to assign licenses. This paper reviews a number of case studies suggesting that economic analysis is most usefully focused on consumer welfare in wireless service markets, the outputs resulting from license use. Econometric evidence from mobile phone markets in twenty-nine countries suggests that auctions do not lower prices or increase usage, while liberalization, increased spectrum allocations and more competitive markets -- produces such pro-consumer results. We use simulations to compare the net social benefits of liberalization against policies suggested in the auction literature to enhance license bids. We argue that increases in bandwidth and competitiveness produce consumer benefits that generally dominate social gains from rent extraction via wireless license auctions.
Multidisciplinary consensus statement on the clinical management of patients with pancreatic cancer
Pancreatic cancer (PC) remains one of the most aggressive tumors with an increasing incidence rate and reduced survival. Although surgical resection is the only potentially curative treatment for PC, only 15-20% of patients are resectable at diagnosis. To select the most appropriate treatment and thus improve outcomes, the diagnostic and therapeutic strategy for each patient with PC should be discussed within a multidisciplinary expert team. Clinical decision-making should be evidence-based, considering the staging of the tumor, the performance status and preferences of the patient. The aim of this guideline is to provide practical and evidence-based recommendations for the management of PC
Differences in In Vitro Properties of Pancreatin Preparations for Pancreatic Exocrine Insufficiency as Marketed in Russia and CIS
BACKGROUND: Pancreatic enzyme-replacement therapy (PERT), provided as pancreatin to patients with pancreatic exocrine insufficiency (PEI), is considered an essential substitute for the pivotal physiological function the pancreas fulfills in digestion. PEI involves a reduction in the synthesis and secretion of pancreatic enzymes (lipase, protease, amylase), which leads to an inadequate enzymatic response to a meal and consequently to maldigestion and malabsorption of nutrients. The efficacy of PERT is strongly dependent on enzyme activity, dissolution, and pancreatin particle size. OBJECTIVE: The physiological properties of eight pancreatin preparations (nine batches; five different brands) available in Russia and CIS (Commonwealth of Independent States: Armenia, Azerbaijan, Belarus, Kazakhstan, Kyrgyzstan, Moldova, Russia, Tajikistan, Uzbekistan) were investigated. METHODS: The lipase activity, dissolution, and particle size distribution of samples from multiple batches of pancreatin of different strengths were measured. RESULTS: Regarding lipase activities, all pancreatin preparations except Micrazim(R) matched the labeled content. Considerable differences were observed in particle size and dissolution. CONCLUSION: Pancreatin preparations available in Russia and CIS demonstrate product-to-product and batch-to-batch variability regarding the measured properties of lipase activity, dissolution, and particle size. This may impact the efficacy of PERT and therefore clinical outcomes
Designability of alpha-helical Proteins
A typical protein structure is a compact packing of connected alpha-helices
and/or beta-strands. We have developed a method for generating the ensemble of
compact structures a given set of helices and strands can form. The method is
tested on structures composed of four alpha-helices connected by short turns.
All such natural four-helix bundles that are connected by short turns seen in
nature are reproduced to closer than 3.6 Angstroms per residue within the
ensemble. Since structures with no natural counterpart may be targets for ab
initio structure design, the designability of each structure in the ensemble --
defined as the number of sequences with that structure as their lowest energy
state -- is evaluated using a hydrophobic energy. For the case of four
alpha-helices, a small set of highly designable structures emerges, most of
which have an analog among the known four-helix fold families, however several
novel packings and topologies are identified.Comment: 21 pages, 6 figures, to appear in PNA
Plan de negocio para la elaboraci?n de una bebida instant?nea saborizada a base de leche enriquecida con alb?mina de huevo en Lima Metropolitana
En el siguiente plan de negocios se plantea como objetivo principal determinar la viabilidad t?cnica, econ?mica y financiera para la producci?n y comercializaci?n de una bebida instant?nea saborizada a base de leche enriquecida con alb?mina de huevo en el mercado de Lima Metropolitana. Para el diagn?stico del entorno se utiliz? el an?lisis SEPTE y de cinco fuerzas de Porter evidenciando un entorno favorable para productos enriquecidos. El producto se presentar? en bolsas por 120g con las que se podr? preparar 1 Litro de bebida, adem?s en los sabores de Vainilla y Chocolate. Utilizando encuestas cualitativas y Focus group se determin? la intenci?n e intensidad del mercado y se segment? el mercado objetivo en los NSE B y C. Con este mercado se establece como meta posicionarse en un 4% del mismo, en funci?n de esto se dise?a la cadena de suministro, la cual consiste en un abastecimiento gestionado por la empresa, mientras las operaciones de producci?n, almacenamiento y distribuci?n son tercerizadas con una gesti?n de calidad para supervisarlas. Desarrollando esta operaci?n se obtienen en 5 a?os un VAN Financiero de S/. 449,622.92 y un TIR Financiero de 20.73% con un periodo de retorno del capital de 4 a?os y 3 meses
Transcriptional Regulation of the Capsular Polysaccharide Biosynthesis Locus of Streptococcus Pneumoniae: a Bioinformatic Analysis
The polysaccharide capsule of Streptococcus pneumoniae is the main virulence factor, which makes the bacterium resistant to phagocytosis. Expression of capsular polysaccharide must be adjusted at different stages of pneumococcal infection, thus, their transcriptional regulation appears to be crucial. To get insight into the existence of regulatory mechanisms common to most serotypes, a bioinformatic analysis of the DNA region located upstream of the capsular locus was performed. With the exception of serotype 37, the capsular locus is located between dexB and aliA on the pneumococcal chromosome. Up to 26 different sequence organizations were found among pneumococci synthesizing their capsule through a Wzy-polymerase-dependent mechanism, mostly varying according to the presence/absence of distinct insertion elements. As a consequence, only ∼250 bp (including a 107 bp RUP_A element) was conserved in 86 sequences, although only a short (ca. 87 bp) region located immediately upstream of cpsA was strictly conserved in all the sequences analyzed. An exhaustive search for possible operator sequences was done. Interestingly, although the promoter region of serotype 3 isolates completely differs from that of other serotypes, most of the proteins proposed to regulate transcription in serotype 3 pneumococci were also predicted to function as possible regulators in non-serotype 3 S. pneumoniae isolates
The Secret to Job Satisfaction is Low Expectations: How Perceived Working Conditions Differ from Actual Ones
Folding a protein in a computer: An atomic description of the folding/unfolding of protein A
Influence of Polymorphisms Involved in Platelet Activation and Inflammatory Response on Aspirin-Related Upper Gastrointestinal Bleeding: A Case-Control Study
Background: Despite the wide benefits of aspirin and its cost-effectiveness, aspirin prescriptions have been reduced due to idiosyncratic responses in susceptible individuals. Low-dose aspirin and single-nucleotide polymorphisms (SNPs) are independently associated with increased risk of gastrointestinal hemorrhage; however, to-date, no studies investigated the SNP-aspirin interaction effect on upper gastrointestinal hemorrhage (UGIH). Therefore, we aimed to evaluate the role of 25 SNPs in multiple genes involved in platelet activation, angiogenesis and inflammatory response in aspirin-related UGIH. Methods: A multicenter, full case-control study was conducted in patients exposed and unexposed to aspirin. Three hundred twenty-six cases diagnosed with UGIH were matched with 748 controls (1:3) by age, gender, health center, and recruitment date. Only adults of European origin were included. Participants were stratified by aspirin exposure and genotype [(Aspirin(-), wild-type), (Aspirin(+), wild-type), (Aspirin(+), genetic variation), (Aspirin(-), genetic variation)]. For each SNP, the Odds Ratio of UGIH and their 95% confidence intervals were estimated in each subgroup by using the generalized linear mixed models for dependent binomial variables. SNP-aspirin interaction effect was estimated through Relative Excess Risk due to Interaction (RERI) measures. Results: We observed two categories of SNPs that might modify the risk magnitude of UGIH in aspirin consumers. Seven SNPs (rs1387180 A > G, rs2238631 T > C, rs1799964 T > C, rs5050 T > C/T > G, rs689466 T > C, rs1799983 T > A/T > G, and rs7756935 C > A) were "positive modifiers" associated with an excess of risk from aspirin exposure and carrying that genetic variation (1.75 T, rs1131882 G > A, rs4311994 C > T, rs10120688 G > A, rs4251961 T > C, rs3778355 G > C, rs1330344 C > T, rs5275 A > G/A > T, and rs3779647 C > T) were "negative modifiers" and associated with a reduced risk in aspirin users (-2.74 </= RERI </= -0.95). Conclusion: This preliminary study suggests that polymorphisms in genes involved in platelets activity, angiogenesis and inflammatory response might modify the risk of aspirin-related UGIH. Further studies with larger sample size and in different populations are needed to confirm our findings. If confirmed, this might have great impact on public health, thanks to aspirin's prophylactic properties in diseases of high incidence and severity
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