Renegociaci?n de contratos de concesi?n en infraestructura de transporte : diagn?stico, an?lisis y propuestas de mejora

Como ha ocurrido en muchos otros pa?ses, en el Per?, tradicionalmente, el Estado ha sido el ?nico en asumir la responsabilidad de proporcionar infraestructura p?blica y de prestar los servicios asociados con esta. Vali?ndose de sus propios medios, ha tratado, durante muchos a?os, de cumplir con la responsabilidad de brindar a la poblaci?n carreteras, aeropuertos, plantas de tratamiento de agua, centrales de generaci?n el?ctrica, etc. Finalmente, el Estado peruano comprendi? que no ser?a posible lograr el desarrollo del pa?s apelando ?nicamente a sus recursos propios, sino que tambi?n era necesario contar con la inversi?n y la capacidad de la empresa privada, para incrementar las posibilidades de alcanzar sus metas. Este nuevo modelo econ?mico permiti? que el Estado delegue la gesti?n de los servicios p?blicos en una administraci?n privada, sin perjuicio de retener su titularidad y competencia para ejercer las correspondientes funciones de regulaci?n y fiscalizaci?n. Por tanto, el objetivo general del presente trabajo es proponer mejoras al dise?o inicial de los contratos de concesi?n en infraestructura de transportes. Para ello, se presenta y analiza el marco conceptual de los contratos de concesi?n en cuanto contratos administrativos, as? como las teor?as relacionadas con su renegociaci?n. Luego se describe el marco normativo e institucional del sistema de concesiones del Per?, as? como las normas aplicables a la renegociaci?n de los contratos de concesi?n en el sector Transportes. A continuaci?n se efect?a el diagn?stico, se identifican y analizan los temas considerados m?s relevantes y que con mayor frecuencia son objeto de modificaci?n contractual. Finalmente, se formulan propuestas de mejora del dise?o de los contratos de concesi?n. El objetivo es que estas permitan perfeccionar los documentos contractuales de los proyectos a partir de los cuales se originan los futuros procesos de promoci?n de la inversi?n privada, espec?ficamente en aquellos temas en los cuales resulta posible hallar una soluci?n a trav?s del dise?o contractual

A Search for Photons with Energies Above 2X10(17) eV Using Hybrid Data from the Low-Energy Extensions of the Pierre Auger Observatory

Ultra-high-energy photons with energies exceeding 10(17) eV offer a wealth of connections to different aspects of cosmic-ray astrophysics as well as to gamma-ray and neutrino astronomy. The recent observations of photons with energies in the 10(15) eV range further motivate searches for even higher-energy photons. In this paper, we present a search for photons with energies exceeding 2 x 10(17) eV using about 5.5 yr of hybrid data from the low-energy extensions of the Pierre Auger Observatory. The upper limits on the integral photon flux derived here are the most stringent ones to date in the energy region between 10(17) and 10(18) eV

K0S and Λ production in Pb-Pb collisions at sNN−−−−√=2.76 TeV

The ALICE measurement of K0S and Λ production at midrapidity in Pb-Pb collisions at sNN−−−√=2.76  TeV is presented. The transverse momentum (pT) spectra are shown for several collision centrality intervals and in the pT range from 0.4  GeV/c (0.6  GeV/c for Λ) to 12  GeV/c. The pT dependence of the Λ/K0S ratios exhibits maxima in the vicinity of 3  GeV/c, and the positions of the maxima shift towards higher pT with increasing collision centrality. The magnitude of these maxima increases by almost a factor of three between most peripheral and most central Pb-Pb collisions. This baryon excess at intermediate pT is not observed in pp interactions at s√=0.9  TeV and at s√=7  TeV. Qualitatively, the baryon enhancement in heavy-ion collisions is expected from radial flow. However, the measured pT spectra above 2  GeV/c progressively decouple from hydrodynamical-model calculations. For higher values of pT, models that incorporate the influence of the medium on the fragmentation and hadronization processes describe qualitatively the pT dependence of the Λ/K0S ratio

Global age-sex-specific fertility, mortality, healthy life expectancy (HALE), and population estimates in 204 countries and territories, 1950–2019: a comprehensive demographic analysis for the Global Burden of Disease Study 2019

Background: Accurate and up-to-date assessment of demographic metrics is crucial for understanding a wide range of social, economic, and public health issues that affect populations worldwide. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 produced updated and comprehensive demographic assessments of the key indicators of fertility, mortality, migration, and population for 204 countries and territories and selected subnational locations from 1950 to 2019. Methods: 8078 country-years of vital registration and sample registration data, 938 surveys, 349 censuses, and 238 other sources were identified and used to estimate age-specific fertility. Spatiotemporal Gaussian process regression (ST-GPR) was used to generate age-specific fertility rates for 5-year age groups between ages 15 and 49 years. With extensions to age groups 10–14 and 50–54 years, the total fertility rate (TFR) was then aggregated using the estimated age-specific fertility between ages 10 and 54 years. 7417 sources were used for under-5 mortality estimation and 7355 for adult mortality. ST-GPR was used to synthesise data sources after correction for known biases. Adult mortality was measured as the probability of death between ages 15 and 60 years based on vital registration, sample registration, and sibling histories, and was also estimated using ST-GPR. HIV-free life tables were then estimated using estimates of under-5 and adult mortality rates using a relational model life table system created for GBD, which closely tracks observed age-specific mortality rates from complete vital registration when available. Independent estimates of HIV-specific mortality generated by an epidemiological analysis of HIV prevalence surveys and antenatal clinic serosurveillance and other sources were incorporated into the estimates in countries with large epidemics. Annual and single-year age estimates of net migration and population for each country and territory were generated using a Bayesian hierarchical cohort component model that analysed estimated age-specific fertility and mortality rates along with 1250 censuses and 747 population registry years. We classified location-years into seven categories on the basis of the natural rate of increase in population (calculated by subtracting the crude death rate from the crude birth rate) and the net migration rate. We computed healthy life expectancy (HALE) using years lived with disability (YLDs) per capita, life tables, and standard demographic methods. Uncertainty was propagated throughout the demographic estimation process, including fertility, mortality, and population, with 1000 draw-level estimates produced for each metric. Findings: The global TFR decreased from 2•72 (95% uncertainty interval [UI] 2•66–2•79) in 2000 to 2•31 (2•17–2•46) in 2019. Global annual livebirths increased from 134•5 million (131•5–137•8) in 2000 to a peak of 139•6 million (133•0–146•9) in 2016. Global livebirths then declined to 135•3 million (127•2–144•1) in 2019. Of the 204 countries and territories included in this study, in 2019, 102 had a TFR lower than 2•1, which is considered a good approximation of replacement-level fertility. All countries in sub-Saharan Africa had TFRs above replacement level in 2019 and accounted for 27•1% (95% UI 26•4–27•8) of global livebirths. Global life expectancy at birth increased from 67•2 years (95% UI 66•8–67•6) in 2000 to 73•5 years (72•8–74•3) in 2019. The total number of deaths increased from 50•7 million (49•5–51•9) in 2000 to 56•5 million (53•7–59•2) in 2019. Under-5 deaths declined from 9•6 million (9•1–10•3) in 2000 to 5•0 million (4•3–6•0) in 2019. Global population increased by 25•7%, from 6•2 billion (6•0–6•3) in 2000 to 7•7 billion (7•5–8•0) in 2019. In 2019, 34 countries had negative natural rates of increase; in 17 of these, the population declined because immigration was not sufficient to counteract the negative rate of decline. Globally, HALE increased from 58•6 years (56•1–60•8) in 2000 to 63•5 years (60•8–66•1) in 2019. HALE increased in 202 of 204 countries and territories between 2000 and 2019. Interpretation: Over the past 20 years, fertility rates have been dropping steadily and life expectancy has been increasing, with few exceptions. Much of this change follows historical patterns linking social and economic determinants, such as those captured by the GBD Socio-demographic Index, with demographic outcomes. More recently, several countries have experienced a combination of low fertility and stagnating improvement in mortality rates, pushing more populations into the late stages of the demographic transition. Tracking demographic change and the emergence of new patterns will be essential for global health monitoring. Funding: Bill & Melinda Gates Foundation. © 2020 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 licens

Global burden of 87 risk factors in 204 countries and territories, 1990�2019: a systematic analysis for the Global Burden of Disease Study 2019

Background: Rigorous analysis of levels and trends in exposure to leading risk factors and quantification of their effect on human health are important to identify where public health is making progress and in which cases current efforts are inadequate. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 provides a standardised and comprehensive assessment of the magnitude of risk factor exposure, relative risk, and attributable burden of disease. Methods: GBD 2019 estimated attributable mortality, years of life lost (YLLs), years of life lived with disability (YLDs), and disability-adjusted life-years (DALYs) for 87 risk factors and combinations of risk factors, at the global level, regionally, and for 204 countries and territories. GBD uses a hierarchical list of risk factors so that specific risk factors (eg, sodium intake), and related aggregates (eg, diet quality), are both evaluated. This method has six analytical steps. (1) We included 560 risk�outcome pairs that met criteria for convincing or probable evidence on the basis of research studies. 12 risk�outcome pairs included in GBD 2017 no longer met inclusion criteria and 47 risk�outcome pairs for risks already included in GBD 2017 were added based on new evidence. (2) Relative risks were estimated as a function of exposure based on published systematic reviews, 81 systematic reviews done for GBD 2019, and meta-regression. (3) Levels of exposure in each age-sex-location-year included in the study were estimated based on all available data sources using spatiotemporal Gaussian process regression, DisMod-MR 2.1, a Bayesian meta-regression method, or alternative methods. (4) We determined, from published trials or cohort studies, the level of exposure associated with minimum risk, called the theoretical minimum risk exposure level. (5) Attributable deaths, YLLs, YLDs, and DALYs were computed by multiplying population attributable fractions (PAFs) by the relevant outcome quantity for each age-sex-location-year. (6) PAFs and attributable burden for combinations of risk factors were estimated taking into account mediation of different risk factors through other risk factors. Across all six analytical steps, 30 652 distinct data sources were used in the analysis. Uncertainty in each step of the analysis was propagated into the final estimates of attributable burden. Exposure levels for dichotomous, polytomous, and continuous risk factors were summarised with use of the summary exposure value to facilitate comparisons over time, across location, and across risks. Because the entire time series from 1990 to 2019 has been re-estimated with use of consistent data and methods, these results supersede previously published GBD estimates of attributable burden. Findings: The largest declines in risk exposure from 2010 to 2019 were among a set of risks that are strongly linked to social and economic development, including household air pollution; unsafe water, sanitation, and handwashing; and child growth failure. Global declines also occurred for tobacco smoking and lead exposure. The largest increases in risk exposure were for ambient particulate matter pollution, drug use, high fasting plasma glucose, and high body-mass index. In 2019, the leading Level 2 risk factor globally for attributable deaths was high systolic blood pressure, which accounted for 10·8 million (95 uncertainty interval UI 9·51�12·1) deaths (19·2% 16·9�21·3 of all deaths in 2019), followed by tobacco (smoked, second-hand, and chewing), which accounted for 8·71 million (8·12�9·31) deaths (15·4% 14·6�16·2 of all deaths in 2019). The leading Level 2 risk factor for attributable DALYs globally in 2019 was child and maternal malnutrition, which largely affects health in the youngest age groups and accounted for 295 million (253�350) DALYs (11·6% 10·3�13·1 of all global DALYs that year). The risk factor burden varied considerably in 2019 between age groups and locations. Among children aged 0�9 years, the three leading detailed risk factors for attributable DALYs were all related to malnutrition. Iron deficiency was the leading risk factor for those aged 10�24 years, alcohol use for those aged 25�49 years, and high systolic blood pressure for those aged 50�74 years and 75 years and older. Interpretation: Overall, the record for reducing exposure to harmful risks over the past three decades is poor. Success with reducing smoking and lead exposure through regulatory policy might point the way for a stronger role for public policy on other risks in addition to continued efforts to provide information on risk factor harm to the general public. Funding: Bill & Melinda Gates Foundation. © 2020 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 licens

Global, regional, and national burden of suicide mortality 1990 to 2016: Systematic analysis for the Global Burden of Disease Study 2016

Objectives To use the estimates from the Global Burden of Disease Study 2016 to describe patterns of suicide mortality globally, regionally, and for 195 countries and territories by age, sex, and Socio-demographic index, and to describe temporal trends between 1990 and 2016. Design Systematic analysis. Main outcome measures Crude and age standardised rates from suicide mortality and years of life lost were compared across regions and countries, and by age, sex, and Socio-demographic index (a composite measure of fertility, income, and education). Results The total number of deaths from suicide increased by 6.7 (95 uncertainty interval 0.4 to 15.6) globally over the 27 year study period to 817 000 (762 000 to 884 000) deaths in 2016. However, the age standardised mortality rate for suicide decreased by 32.7 (27.2 to 36.6) worldwide between 1990 and 2016, similar to the decline in the global age standardised mortality rate of 30.6. Suicide was the leading cause of age standardised years of life lost in the Global Burden of Disease region of high income Asia Pacific and was among the top 10 leading causes in eastern Europe, central Europe, western Europe, central Asia, Australasia, southern Latin America, and high income North America. Rates for men were higher than for women across regions, countries, and age groups, except for the 15 to 19 age group. There was variation in the female to male ratio, with higher ratios at lower levels of Socio-demographic index. Women experienced greater decreases in mortality rates (49.0, 95 uncertainty interval 42.6 to 54.6) than men (23.8, 15.6 to 32.7). Conclusions Age standardised mortality rates for suicide have greatly reduced since 1990, but suicide remains an important contributor to mortality worldwide. Suicide mortality was variable across locations, between sexes, and between age groups. Suicide prevention strategies can be targeted towards vulnerable populations if they are informed by variations in mortality rates. © Published by the BMJ Publishing Group Limited

Efectos en la estructura multiplicativa desde la resoluci?n de problemas en estudiantes del grado cuarto de la ?Instituci?n Educativa la Florida Sede Cucal la Brecha y Sede Central? del municipio de Rovira-Tolima

62 p.El objeto de la presente investigaci?n es determinar el efecto en la estructura multiplicativa desde la resoluci?n de problemas en estudiantes del grado cuarto de la ?instituci?n educativa la Florida sede Cucal la Brecha y sede Central? del municipio de Rovira-Tolima. Los objetivos espec?ficos son evaluar la secuencia did?ctica, comparar el efecto en la estructura multiplicativa desde la resoluci?n de problemas con la ense?anza tradicional orientada a la t?cnica algor?tmica y establecer el g?nero que presenta mayor dificultad en la estructura multiplicativa desde la resoluci?n de problemas. El enfoque de la investigaci?n es cuantitativo de tipo descriptivo, con el dise?o de Solomon, se tienen en cuenta los estudiantes de grado 4 de la Instituci?n Educativa La Florida sede Central y sede Cucal la Brecha. Por medio de la secuencia did?ctica se busca el desarrollo y fortalecimiento de la competencia: resoluci?n de problemas, que involucra la estructura multiplicativa. A trav?s de situaciones de la vida diaria, permitiendo a los estudiantes que descubran la importancia de aprender matem?ticas, la necesidad, el gusto y la utilidad.The purpose of the present investigation is to determine the effect on the multiplicative structure from the resolution of problems in students of the fourth grade of the "educational institution Florida headquarters Cucal la Brecha and Central headquarters" of the municipality of Rovira-Tolima. The specific objectives are evaluate the didactic sequence, compare the effect on the multiplicative structure from the resolution of problems with traditional teaching oriented to the algorithmic technique and establish the gender that presents greater difficulty in the multiplicative structure from problem solving. The research approach is quantitative descriptive, with the design of Solomon, students in grade 4 of the La Florida Educational Institution Central headquarters and Cucal headquarters are taken into account. By the middle of the didactic sequence for the development and strengthening of competition: troubleshooting, which involves the multiplicative structure. Through situations of daily life, allowing students to discover the importance of learning mathematics, the need, taste, and the utility

Evidencia de que Nephelium lappaceum no es hospedante de tres especies de mosca de la fruta (Tephritidae) en Honduras

4 tab. 5 ref.El rambut?n, Nephelium lappaceum L., es un valioso cultivo tropical ex?tico con potencial de exportaci?n hacia los Estados Unidos. Sin embargo, la presencia de especies de moscas de la fruta con restricciones cuarentenarias prohibe su exportaci?n como fruta fresca de Centro a Norte Am?rica. Nunca se ha observado da?o de larvas de moscas de la fruta en el rambut?n sembrado en Honduras, por lo que com?nmente se cree que este no es un hospedante natural de moscas de la fruta. Con el prop?sito de evaluar esta hip?tesis, la Fundaci?n Hondure?a de Investigaci?n Agr?cola (FHIA) condujo durante 1990, 1991 y 1994 series de experimentos de exposici?n forzada, donde frutas de rambut?n fueron evaluadas contra tres especies distintas de moscas de la fruta (Ceratitis capitata Wiedemann, Anastrepha ludens Loew y Anastrepha obliqua Macquart). En ninguna de las 13,460 frutas de rambut?n evaluadas durante los tres a?os del estudio se pudo constatar la presencia de marcas de oviposici?n o presencia de larvas en la pulpa. Los resultados demostraron que el rambut?n no es un hu?sped susceptible a las especies de moscas de la fruta de Centro Am?rica. Rambut?n, Nephelium lappaceum L., is a valuable exotic tropical crop with potential for exportation to the U.S. However, the presence of fruit flies species with quarantine restrictions prohibits its exportation as a fresh fruit from Central to North America. The Rambutan planted in Honduras has never been observed bearing damage of fruit flies and it is widely believed that Rambutan is not a natural host of these fruit flies. With the purpose of evaluating this hypothesis, the FHIA conducted during 1990, 1991 and 1994 a series of forced infestation tests where Rambutan was evaluated against three different species of fruit flies (Ceratitis capitata Wiedemann, Anastrepha ludens Loew and Anastrepha obliqua Macquart). There were neither oviposition punctures nor larvae in the pulp of the 13,460 Rambutan fruits evaluated during the tree years of research. The results demonstrate that Rambutan is not a susceptible host for these fruit fly species