In this study, the ionospheric observations from ionosondes, GPS receivers, and incoherent scatter radars (ISR) at low and middle latitudes were used to investigate the contribution of the bottomside and topside ionosphere to the total electron content (TEC) during the September 2005 and December 2006 geomagnetic storms. It was found that the contribution of the bottomside TEC below F2 peak (BTEC) to the ionosonde ionospheric TEC (ionosonde ITEC), namely, BTEC/ITEC was almost constant during both quiet and storm times, while the ratio of BTEC to GPS TEC (i.e., BTEC/GPS‐TEC) underwent obvious diurnal variations at all stations. The BTEC/GPS‐TEC during the positive phase was similar to that during quiet time, regardless of the formation mechanisms of the observed positive phases. Moreover, our analysis revealed that the ISR calculated BTEC/ITEC during positive ionospheric phases was co...

The performance of the airline industry has been widely studied using data envelopment analysis (DEA). Many existing DEA-based airline performance studies have used the standard DEA model, with some minor modifications. These studies have ignored the internal structure relative to the measures characterizing airline operations performance. In the current paper, airline performance is measured using a two-stage process. In the first stage, resources (fuel, salaries, and other factors) are used to maintain the fleet size and load factor. In the second stage, the fleet size and load factors generate revenue. The model used is called the centralized efficiency model where two stages are used to optimize performance simultaneously. The approach generates efficiency decomposition for the two individual stages. The use of this centralized DEA model enables obtaining insights not available from ...

La presente investigación tiene como objetivo Determinar de qué manera la Depreciación Acelerada incide en el Impuesto a la Renta en las empresas comerciales de Comas, año 2021. La importancia de la presente investigación es mostrar una posible solución basándose en teorías a la problemática de las empresas comerciales de Comas donde hay una falta de conocimiento existente acerca del método de depreciación acelerada que puede ser aprovechada para su mejora como organización en la reducción del pago de su impuesto a la renta anual. Para la presente el tipo de investigación es básica y de nivel descriptivo, siendo su diseño el no experimental y de corte transversal, se utilizó un instrumento para la recolección de datos de la muestra siendo 40 personas. Para la medición de la confiabilidad se midió bajo el coeficiente de Alfa de Cronbach y la comprobación de las hipót...

abarca el tema del intercambio entre estudiar y trabajar en los adolescentes del Perú para los años 2015 y 2019, donde se propone la inclusión de un análisis de pobreza multidimensional. Se usó la ENAHO como base de datos secundario (para ambos años) y para la obtención de resultados se usó la metodología biprobit, proporcionándonos cuatro iteraciones, quedándonos con la iteración de interés (desertar y trabajar). Evidenciamos que el adolescente que es pobre multidimensional tiene una probabilidad mayor de 2% de desertar e ir a trabajar, además, la pobreza monetaria no tiene significancia en el estudio. Ser de área urbana provoca menos probabilidad de deserción y trabajo adolescente, y que el adolescente sea varón aumenta la probabilidad de desertar y trabajar. Se concluye que incluir el análisis de pobreza multidimensional para la medición de fenómenos sociales como ...

Este documento describe el conjunto de datos COVID-19 emparejados de las cohortes de Niños del Milenio en Perú creado por el equipo de Niños del Milenio. El conjunto de datos emparejados combina los datos administrativos de COVID-19 con el amplio conjunto de datos longitudinales del estudio Niños del Milenio en Perú. Los autores documentan los pasos dados para crear un conjunto de variables que miden el número de casos de COVID-19, muertes y dosis de vacunas aplicadas en los distritos donde residen los participantes de Niños del Milenio, junto con la duración de los periodos de bloqueo que soportaron. Recopilaron datos administrativos y los integraron con los conjuntos de datos de Niños del Milenio de la convocatoria 2 (de agosto a octubre de 2020), la convocatoria 3 (de noviembre a diciembre de 2020), la convocatoria 4 (de agosto a septiembre de 2021) y la convocatoria 5 (de no...

Increased glacier melting runoff in Antarctica involves intensification of freshwater, nutrients, sediments and organic matter inputs from land to the sea, which is impacting coastal ecosystems. Basic environmental characteristics of water and biochemical composition of suspended particulate organic matter (POM) both in the proglacial melting runoff system (PROGLARS) of Collins Glacier and marine surface waters of Collins Bay was studied based on organic biopolymers and molecular level analysis of amino acids (AAs), to discern among sources and degradation state in the two environments. Hierarchical Clustering Analysis revealed that PROGLARS stations and marine stations form two distinct groups in terms of water physicochemical characteristics and suspended POM biochemical composition. These differences are the consequence of low restricted contribution of freshwater from Collins Glacier...

La estructura de las exportaciones peruanas se ha basado a lo largo de los años en productos tradicionales cuya naturaleza se puede explicar a partir del patrón de ventajas comparativas que posee el Perú. Con el objetivo de intensificar los flujos comerciales hacia un mayor número de mercados, el Perú ha firmado muchos tratados comerciales y, siguiendo con la estrategia, ha concluido negociaciones del Acuerdo Trans-Pacific Partnership (TPP). Sin embargo, las participaciones de mercado del Perú en las importaciones de los países con los que tiene tratado comerciales son bajas lo cual refleja un pobre nivel de aprovechamiento de los mismos. El objetivo de este trabajo es identificar las potenciales oportunidades comerciales que tiene el Perú dentro del marco del TPP mediante el uso de índices comerciales cómo el índice de ventajas comparativas y la clasificación de las estrateg...

Ionospheric observations from the ground‐based GPS receiver network, CHAMP and GRACE satellites and ionosondes were used to examine topside and bottomside ionospheric variations at low and middle latitudes over the Pacific and American sectors during the October 2003 superstorms. The latitudinal variation and the storm time response of the ground‐based GPS total electron content (TEC) were generally consistent with those of the CHAMP and GRACE up‐looking TEC. The TECs at heights below the satellite altitudes during the main phases were comparable to, or even less than, the quiet time values. However, the storm time CHAMP and GRACE up‐looking TECs showed profound increases at low and middle latitudes. The ground‐based TEC and ionosonde data were also combined to study the TEC variations below and above the F2 peak height (hmF2). The topside TECs above hmF2 at low and middle lati...

Purpose: This phase I study was performed to determine the safety profile, maximum tolerated dose (MTD) and biological activity of lonafarnib (SCH 66336). Single-dose and multi-dose pharmacokinetics were conducted. Methods: Twenty-one patients with advanced solid tumors were enrolled. Each patient received single-dose administration on day 1, cycle 1 then switched to a twice daily (BID) dosing regimen on days 2-14 of a 28-day cycle; subsequent cycles continued BID dosing on days 1-14. Dose-limiting toxicity (DLT) was assessed during the cycle one; toxicity evaluation was closely monitored throughout the treatment. Radiographic scans were completed to assess tumor response. Blood and urine pharmacokinetics were evaluated on days 1 and 14 in cycle 1. SCH 66336- induced farnesylation inhibition was assessed via conversion of prelamin A to lamin in buccal mucosa. Results: DLT and most common...

In order to enhance the geoscientific collaboration between China and Peru using China’s advanced geochemical investigation and research methods, the China Geological Survey (CGS) and Peru, Instituto Geológico, Minero y Metalúrgico (INGEMMET) jointly conducted a multipurpose geochemical survey in the Mantaro Basin of central Peru. The samples were collected and analyzed in Chinese laboratory according to applicable Chinese national standards. According to the results, the soil of the study area was in general weakly alkaline, with strong enrichment of Au and relatively enriched indicators such as I, C, Corg, Cd, and N. The soil nutrient indicators N and P were relatively abundant, but K was lacking. The comprehensive nutrient grade was mainly “relatively rich” (Grade 2), accounting for 74.1% of the total area, indicating good soil fertility. In terms of soil environmental assessm...

The Earth’s Ionosphere-Thermosphere-Electrodynamics (I-T-E) system varies markedly on a range of spatial and temporal scales and these variations have adverse effects on human operations and systems, including high-frequency communications, over-the-horizon radars, and survey and navigation systems that use Global Positioning System (GPS) satellites. Consequently, there is a need to elucidate the underlying physical processes that lead to space weather disturbances and to both mitigate and forecast near-Earth space weather. The meteorologists and oceanographers have shown that data assimilation models are superior to global physics-based models for specifications and forecasts, but only during the last 15 years have they been used for near-Earth investigations as more global (space and ground-based) measurements became available. Although data assimilation models produce better specifi...

Background The Pittsburgh Sleep Quality Index (PSQI) and the Epworth Sleepiness Scale (ESS) are questionnaires used to assess sleep quality and excessive daytime sleepiness in clinical and population-based studies. The present study aimed to evaluate the construct validity and factor structure of the PSQI and ESS questionnaires among young adults in four countries (Chile, Ethiopia, Peru and Thailand). Methods A cross-sectional study was conducted among 8,481 undergraduate students. Students were invited to complete a self-administered questionnaire that collected information about lifestyle, demographic, and sleep characteristics. In each country, the construct validity and factorial structures of PSQI and ESS questionnaires were tested through exploratory and confirmatory factor analyses (EFA and CFA). Results The largest component-total correlation coefficient for sleep quality as asse...

Background: There are limited data from retrospective studies regarding whether survival outcomes after laparoscopic or robot-assisted radical hysterectomy (minimally invasive surgery) are equivalent to those after open abdominal radical hysterectomy (open surgery) among women with early-stage cervical cancer. Methods: In this trial involving patients with stage IA1 (lymphovascular invasion), IA2, or IB1 cervical cancer and a histologic subtype of squamous-cell carcinoma, adenocarcinoma, or adenosquamous carcinoma, we randomly assigned patients to undergo minimally invasive surgery or open surgery. The primary outcome was the rate of disease-free survival at 4.5 years, with noninferiority claimed if the lower boundary of the two-sided 95% confidence interval of the between-group difference (minimally invasive surgery minus open surgery) was greater than -7.2 percentage points (i.e., clos...