501 research outputs found
The Efficiency and Evolution of R&D Networks
This work introduces a new model to investigate the efficiency and evolution of networks of firms exchanging knowledge in R&D partnerships. We first examine the efficiency of a given network structure in terms of the maximization of total profits in the industry. We show that the efficient network structure depends on the marginal cost of collaboration. When the marginal cost is low, the complete graph is efficient. However, a high marginal cost implies that the efficient network is sparser and has a core-periphery structure. Next, we examine the evolution of the network struc- ture when the decision on collaborating partners is decentralized. We show the existence of mul- tiple equilibrium structures which are in general inefficient. This is due to (i) the path dependent character of the partner selection process, (ii) the presence of knowledge externalities and (iii) the presence of severance costs involved in link deletion. Finally, we study the properties of the emerg- ing equilibrium networks and we show that they are coherent with the stylized facts of R&D net- works.R&D networks, technology spillovers, network efficiency, network formation
Spatial Localization in Manufacturing: A Cross-Country Analysis
This paper employs a homogeneous-firm database to investigate industry localization in European countries. More specifically, it compares, across industries and countries, the predictions of two of the most popular localization indexes, that is, the Ellison and Glaeser index of 1997 and the Duranton and Overman index of 2005. Independently from the index used, it is found that localization is a pervasive phenomenon in all countries studied; and the degree of localization is very unevenly distributed across industries in each country. Furthermore, it is shown that in all countries localized sectors are mainly ‘traditional’ sectors or, if one controls for country industrial structures, science-based sectors. Moreover, it is found that the two indexes significantly diverge in predicting the intensity of localization of the same industry both across and within countries. In turn, these differences point to the different role played by pecuniary versus non-pecuniary externalities in driving firms' location decisions
Are Output Growth-Rate Distributions Fat-Tailed? Some Evidence from OECD Countries
This work explores some distributional properties of aggregate output growth-rate time series. We show that, in the majority of OECD countries, output growth-rate distributions are well approximated by symmetric exponential power densities with tails much fatter than those of a Gaussian (but with finite moments of any order). Fat tails robustly emerge in output growth rates independently of: (i) the way we measure aggregate output; (ii) the family of densities employed in the estimation; (iii) the length of time lags used to compute growth rates. We also show that fat tails still characterize output growth-rate distributions even after one washes away outliers, autocorrelation and heteroscedasticity
Electrochemical biosensors for tracing cyanotoxins in food and environmental matrices
The adoption of electrochemical principles to realize on-field analytical tools for detecting pollutants represents a great possibility for food safety and environmental applications. With respect to the existing transduction mechanisms, i.e., colorimetric, fluorescence, piezoelectric etc., electrochemical mechanisms offer the tremendous advantage of being easily miniaturized, connected with low cost (commercially available) readers and unaffected by the color/turbidity of real matrices. In particular, their versatility represents a powerful approach for detecting traces of emerging pollutants such as cyanotoxins. The combination of electrochemical platforms with nanomaterials, synthetic receptors and microfabrication makes electroanalysis a strong starting point towards decentralized monitoring of toxins in diverse matrices. This review gives an overview of the electrochemical biosensors that have been developed to detect four common cyanotoxins, namely microcystin-LR, anatoxin-a, saxitoxin and cylindrospermopsin. The manuscript provides the readers a quick guide to understand the main electrochemical platforms that have been realized so far, and the presence of a comprehensive table provides a perspective at a glance
Genetic Differentiation of Lymphoblastic Sarcoma Histocompatibility Sites in DBA/1J and C57BL/6 Mice
Author Institution: Department of Biological Sciences, Kent State UniversityA chemically induced, 20-methylcholanthrene, lymphoblastic sarcoma, in DBA/1J mice was used to determine the histocompatibility of the tumor between the DBA/1J and C57BL/GJ strains. Although 8 different histocompatibility sites exist between the 2 strains, this work demonstrated that these 8 sites were transmitted and expressed as a 5 unit discrete factor phenotypic variation. Fi x Fi hybrid animals were tested through the Fg generation and showed that only 5 linkage groups are involved in the transmission of the various histocompatibility sites. Survivors of the implanted F9 generation were used as progenitors for the Fi0 generation. Tumor take frequencies with the Fi0 generation demonstrated that the inheritance of tumor susceptibility behaved as a discrete function of a 5 unit inheritance factor
Un-biodegradable and biodegradable plastic sheets modify the soil properties after six months since their applications
Nowadays, microplastics represent emergent pollutants in terrestrial ecosystems that exert impacts on soil properties, affecting key soil ecological functions. In agroecosystems, plastic mulching is one of the main sources of plastic residues in soils. The present research aimed to evaluate the effects of two types of plastic sheets (un-biodegradable and biodegradable) on soil abiotic (pH, water content, concentrations of organic and total carbon, and total nitrogen) and biotic (respiration, and activities of hydrolase, dehydrogenase, β-glucosidase and urease) properties, and on phytotoxicity (germination index of Sorghum saccharatum L. and Lepidium sativum L.). Results revealed that soil properties were mostly affected by exposure time to plastics rather than the kind (un-biodegradable and biodegradable) of plastics. After six months since mesocosm setting up, the presence of un-biodegradable plastic sheets significantly decreased soil pH, respiration and dehydrogenase activity and increased total and organic carbon concentrations, and toxicity highlighted by S. saccharatum L. Instead, the presence of biodegradable plastic sheets significantly decreased dehydrogenase activity and increased organic carbon concentrations. An overall temporal improvement of the investigated properties in soils covered by biodegradable plastic sheets occurred
Triple peptide vaccination as consolidation treatment in women affected by ovarian and breast cancer: clinical and immunological data of a phase I/II clinical trial
Vaccination with priming and expansion of tumour
reacting T cells is an important therapeutic option to be used
in combination with novel checkpoint inhibitors to increase
the specificity of the T cell infiltrate and the efficacy of the
treatment. In this phase I/II study, 14 high-risk disease-free
ovarian (OC) and breast cancer (BC) patients after completion
of standard therapies were vaccinated with MUC1, ErbB2
and carcinoembryonic antigen (CEA) HLA-A2+-restricted
peptides and Montanide. Patients were subjected to 6 doses
of vaccine every two weeks and a recall dose after 3 months.
ECOG grade 2 toxicity was observed at the injection site. Eight
out of 14 patients showed specific CD8+ T cells to at least one
antigen. None of 4 patients vaccinated for compassionate use
showed a CD8 activation. An OC patient who suffered from
a lymph nodal recurrence, showed specific anti-ErbB2 CD8+
T cells in the bulky aortic lymph nodes suggesting homingof the activated T cells. Results confirm that peptide vaccination
strategy is feasible, safe and well tolerated. In particular
OC patients appear to show a higher response rate compared
to BC patients. Vaccination generates a long-lasting immune
response, which is strongly enhanced by recall administrations.
The clinical outcome of patients enrolled in the trial
appears favourable, having registered no deceased patients
with a minimum follow-up of 8 years. These promising data,
in line with the results of similar studies, the high compliance
of patients observed and the favourable toxicity profile, support
future trials of peptide vaccination in clinically disease-free
patients who have completed standard treatments
Pressure ulcers management: an economic evaluation
Introduction. Pressure ulcer management represents a growing
problem for medical and social health care systems all over the
world, particularly in European Union countries where the incidence
of pressure ulcers in older persons (> 60 years of age) is
predicted to rise.
Objectives. The aim of this study was to provide evidence for the
lower impact on economic resources of using advanced dressings
for the treatment of pressure ulcers with respect to conventional
simple dressings.
Methods. Two different models of analysis, derived from Activity
Based Costing and Health Technology Assessment, were used to
measure, over a 30-day period, the direct costs incurred by pressure
ulcer treatment for community-residing patients receiving
integrated home care.
Results. Although the mean cost per home care visit was higher in
the advanced dressings patient group than in the simple dressings
patient one (? 22.31 versus ? 16.03), analysis of the data revealed
that the cost of using advanced dressings was lower due to fewer
home care visits (22 versus 11).
Conclusion. The results underline the fact that decision-makers need
to improve their understanding of the advantages of taking a long-term
view with regards to the purchase and use of materials. This could produce
considerable savings of resources in addition to improving treatment
efficacy for the benefit of patients and the health care system
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