1,835 research outputs found
Optimal endowments of public investment: an empirical analysis for the spanish regions
The aim of this paper is to estimate the optimal endowments of public investment in Spanish regions. Starting from the standard dynamic neoclassical model, augmented with the public capital stock, the optimal condition for the provision of public capital would be that, in the steady state, the marginal productivities of both public and private capital should be equal. In the empirical application we will estimate a growth equation derived from a simple Cobb-Douglas production function, where the coefficients on the rates of investment in private and public capital would be their respective marginal productivities. The econometric estimation of such an equation with data for the Spanish regions would provide us estimates of the marginal productivities of both factors, which would allow us to infer whether public capital stock in the Spanish regions would be insufficient or otherwise excessive.
Optimal endowments of public investment: an empirical analysis for the Spanish regions
Following Aschauer's (1989) influential contribution, the role of public investment has been stressed as a crucial factor leading to higher private capital productivity, which would lead in turn to higher growth rates. According to this author, the decline in productivity growth experienced by the US economy during the seventies, would explained to a great extent by the decrease in the provision of public infrastructures during that period. In this way, the next years have witnessed the appearance of a great amount of empirical literature that analysed the impact of public investment on economic growth. Although the first empirical studies made use of aggregate time series for countries, this approach has been also extended to a regional framework using panel data, obtaining results that were quantitatively lower than those found with aggregate data. The reason would be the spillover effects related to the regional endowments of public capital, whose effect would extend not only the own region, but also to the neighbouring regions. In any case, public infrastructure seems to play an important role in the growth process of regions that should not be neglected. On the other hand, the issue of the optimal endowments of public infrastructure has been hardly discussed. In a recent paper, Karras (1997) has developed a simple condition to assess whether public capital is optimally provided, namely, whether the marginal productivities of both private and public capital are equal or not. By estimating a simple growth equation for fifteen European countries during the period 1960-1992, he is unable to reject the null hypothesis that the marginal productivities of private and public capital are equal, so that government investment would be neither underprovided nor overprovided in the fifteen countries of his sample. In this paper we try to address this issue (i.e., whether the endowments of public investment are optimal or not) in a regional framework, using Spanish data for the period 1967-91. Unlike Karras (1997), who assumes that the production function exhibits constant returns to scale in all factors, we are able to generalise his condition without the need of this constraint. On the other hand, the Spanish economy can provide an interesting case of study, since it has experienced a sustained period of growth in the last forty years, which has been accompanied by a strong process of structural change. In particular, the establishment of new regional governments after the restoration of democracy in 1977, coupled with the strong increase experienced by public investment since them, are all of them elements that can justify the interest of the Spanish case for the objectives of this paper. Therefore, in this paper we will first derive the theoretical condition under which public capital would be optimally provided, and then we will provide an empirical application of the model, for the case of the Spanish regions during the period 1965-1995.
Plasmodium diversity in non-malaria individuals from the Bioko Island in Equatorial Guinea (West Central-Africa)
BACKGROUND: In this paper we analyse the Plasmodium sp. prevalence in three villages with different isolation status on the island of Bioko (Equatorial Guinea) where malaria is a hyper-endemic disease. We also describe the genetic diversity of P. falciparum, using several plasmodia proteins as markers which show a high degree of polymorphism (MSP-1 and MSP-2). The results obtained from three different populations are compared in order to establish the impact of human movements and interventions. METHODS: Plasmodium sp. were analysed in three villages on Bioko Island (Equatorial Guinea), one of which (Southern) is isolated by geographical barriers. The semi-nested multiplex polymerase chain reaction (PCR) technique was used to determine the prevalence of the four human plasmodia species. The genotyping and frequency of P. falciparum populations were determined by PCR assay target polymorphism regions of the merozoite surface proteins 1 and 2 genes (MSP-1 and MSP-2). RESULTS: The data obtained show that there are no differences in plasmodia population flow between the Northwest and Eastern regions as regards the prevalence of the different Plasmodium species. The Southern population, on the other hand, shows a minor presence of P. malariae and a higher prevalence of P. ovale, suggesting some kind of transmission isolated from the other two. The P. falciparum genotyping in the different regions points to a considerable allelic diversity in the parasite population on Bioko Island, although this is somewhat higher in the Southern region than the others. There was a correlation between parasitaemia levels and the age of the individual with the multiplicity of infection (MOI). CONCLUSION: Results could be explained by the selection of particular MSP alleles. This would tend to limit diversity in the parasite population and leading up to the extinction of rare alleles. On the other hand, the parasite population in the isolated village has less outside influence and the diversity of P. falciparum is maintained higher. The knowledge of parasite populations and their relationships is necessary to study their implications for control intervention
NGC 604, the Scaled OB Association (SOBA) Prototype. I: Spatial Distribution of the Different Gas Phases and Attenuation by Dust
We have analyzed HST and ground-based data to characterize the different gas
phases and their interaction with the MYC in NGC 604, a GHR in M33. The warm
ionized gas is made out of two components: a high-excitation, high-surface
brightness H II surface located at the faces of the molecular clouds directly
exposed to the ionizing radiation of the central SOBA; and a low-excitation,
low-surface brightness halo that extends to much larger distances from the
ionizing stars. The cavities created by the winds and SN explosions are filled
with X-ray-emitting coronal gas. The nebular lines emitted by the warm gas
experience a variable attenuation as a consequence of the dust distribution,
which is patchy in the plane of the sky and with clouds interspersed among
emission-line sources in the same line of sight. The optical depth at H alpha
as measured from the ratio of the thermal radio continuum to H alpha shows a
very good correlation with the total CO (1-0) column, indicating that most of
the dust resides in the cold molecular phase. The optical depth at H alpha as
measured from the ratio of H alpha to H beta also correlates with the CO
emission but not as strongly as in the previous case. We analyze the difference
between those two measurements and we find that <=11% of the H II gas is hidden
behind large-optical-depth molecular clouds. We detect two candidate compact H
II regions embedded inside the molecular cloud; both are within short distance
of WR/Of stars and one of them is located within 16 pc of a RSG. We estimate
the age of the main stellar generation in NGC 604 to be approx. 3 Myr from the
ionization structure of the H II region. The size of the main cavity is smaller
than the one predicted by extrapolating from single-star wind-blown bubbles.Comment: 50 pages, 15 figures. To appear in the September issue of the
Astronomical Journal. Some of the figures in this version have a very low
resolution due to the absurd limitations (for 2004) imposed on file size by
astro-ph. A full-resolution version of the figures is available at
http://www.stsci.edu/~jmai
Two consecutive phase II studies of oxaliplatin (L-OHP) for treatment of patients with advanced colorectal carcinoma who were resistant to previous treatment with fluoropyrimidines
Background Oxaliplatin (L-OHP) is a platinum complex that possesses activity against human and murine cells in vitro and in vivo, including colorectal carcinoma-derived cell lines, and cells that have been selected for resistance to cisplatin. We report two consecutive phase H trials of L-OHP for treatment of patients with advanced colorectal carcinoma. Patients and methods: Fifty-eight patients were entered in study I, and 51 patients in study II. All of the patients had tumor progression when they were treated, prior to their enrolment, with a fluoropyrimidine-containing regimen. In both trials treatment consisted of L-OHP, 130 mg/m2 by i.v. infusion for two hours; the treatment was repeated every 21 days. Results Response to therapy: Study I: Fifty-five patients were assessed for response. The response rate was 11% (95% CI, 0.03-0.19). Study II: All 51 patients were assessed for response. The response rate was 10% (95% CI, 0.017-0.18). The overall response rate for the 106 evaluated patients was 10% (95% CI, 0.046-0.16). Times to disease progression in responders were 4, 4, 4.5+, 5, 5, 6, 6, 6, 6+, 9, and 13 months. The dose-limiting toxic effect was sensory peripheral neuropathy. The incidence of severe peripheral neuropathy grades was: Study I: grade 3, 23% of patients, and grade 4, 8% of patients. Study II: grade 3, 14% of patients, and grade 4, 4% of patients. Severe neuropathy had a favorable course in all of the patients who had long-term neurologic follow-up. Diarrhea and myeloid impairment were minor. Conclusion L-OHP produced modest, but definite antitumor activity in patients with advanced colorectal carcinoma who were previously resistant to chemotherapy including fluoropyrirnidines. Toxicity is within acceptable limits of tolerance at the dose and schedule of oxaliplatin used in this tria
Glycation does not modify bovine serum albumin (BSA)-induced reduction of rat aortic relaxation: The response to glycated and nonglycated BSA is lost in metabolic syndrome
The effects of nonglycated bovine serum albumin (BSA) and advanced glycosylation end products of BSA (AGE-BSA) on vascular responses of control and metabolic syndrome (MS) rats characterized by hypertriglyceridemia, hypertension, hyperinsulinemia, and insulin resistance were studied. Albumin and in vitro prepared AGE-BSA have vascular effects; however, recent studies indicate that some effects of in vitro prepared AGEs are due to the conditions in which they were generated. We produced AGEs by incubating glucose with BSA for 60 days under sterile conditions in darkness and at 37°C. To develop MS rats, male Wistar animals were given 30% sucrose in drinking water since weanling. Six month old animals were used. Blood pressure, insulin, triglycerides, and serum albumin were increased in MS rats. Contraction of aortic rings elicited with norepinephrine was stronger. There were no effects of nonglycated BSA or AGE-BSA on contractions in control or MS rats; however, both groups responded to L-NAME, an inhibitor of nitric oxide synthesis. Arterial relaxation induced using acetylcholine was smaller in MS rats. Nonglycated BSA and AGE-BSA significantly diminished relaxation in a 35% in the control group but the decrease was similar when using nonglycated BSA and AGE-BSA. This decrease was not present in the MS rats and was not due to increased RAGEs or altered biochemical characteristics of BSA. In conclusion, both BSA and AGE-BSA inhibit vascular relaxation in control artic rings. In MS rats the effect is lost possibly due to alterations in endothelial cells that are a consequence of the illness
Reciprocal responses in the interaction between Arabidopsis and the cell-content feeding chelicerate herbivore spider mite
Most molecular-genetic studies of plant defense responses to arthropod herbivores have focused on insects. However, plant-feeding mites are also pests of diverse plants, and mites induce different patterns of damage to plant tissues than do well-studied insects (e.g. lepidopteran larvae or aphids). The two-spotted spidermite (Tetranychus urticae) is among the most significant mite pests in agriculture, feeding on a staggering number of plant hosts. To understand the interactions between spider mite and a plant at the molecular level, we examined reciprocal genome-wide responses of mites and its host Arabidopsis (Arabidopsis thaliana). Despite differences in feeding guilds, we found that transcriptional responses of Arabidopsis to mite herbivory resembled those observed for lepidopteran herbivores. Mutant analysis of induced plant defense pathways showed functionally that only a subset of induced programs, including jasmonic acid signaling and biosynthesis of indole glucosinolates, are central to Arabidopsis's defense to mite herbivory. On the herbivore side, indole glucosinolates dramatically increased mite mortality and development times. We identified an indole glucosinolate dose-dependent increase in the number of differentially expressedmite genes belonging to pathways associated with detoxification of xenobiotics. This demonstrates that spider mite is sensitive to Arabidopsis defenses that have also been associated with the deterrence of insect herbivores that are very distantly related to chelicerates. Our findings provide molecular insights into the nature of, and response to, herbivory for a representative of a major class of arthropod herbivores
The Impact of Adaptive Leadership Capacity on Complex Organizational Health Systems Outcomes
Nonlinear and chaotic environmental changes characterize health services organizations as complex adaptive systems in which leaders must exercise non-traditional leadership practices to succeed. Health services leaders who have learned and implemented traditional linear management approaches are ill prepared to lead in complex environments. This study tested complexity and adaptive leadership theories of agility and resilience in complex health systems. The purpose of this quantitative cross-sectional internet-based survey study was to quantify relationships between independent variables of agility and resilience and secondary dependent variables of financial, patient satisfaction, quality and human capital outcomes. The impact of turbulence was also examined. Included sample data were collected from 533 employed healthcare leaders using probability-based systematic proportional random sampling methods and were analyzed through correlation, regression, one-way analysis of variance, t tests, and Hayes PROCESS statistical analytics. Agility correlated with and predicted patient satisfaction outcomes. Resilience independently correlated with and predicted financial performance and patient satisfaction outcomes and augmented the correlation and predictability of agility. Agility and resilience cumulatively predicted financial performance outcomes. Turbulence was related to agility, resilience, financial performance, and patient care quality outcomes and mediated relationships with financial and patient care quality outcomes. Health services leaders may apply these findings to promote social change through the implementation of the agile and resilient leadership approaches necessary to achieve organizational performance outcomes that benefit vulnerable populations
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