56 research outputs found
A Meta-Analysis of Technical Efficiency in Farming: A Multi-Country Perspective
The objective of this study is to undertake a meta-analysis seeking to explain the variation in average technical efficiency focusing on the agricultural sector. For this purpose, a meta-analysis of 126 technical efficiency studies on the agricultural sector of developing and developed countries was undertaken. In addition, the study contributes to cross-country productivity literature because the existing body of work in this area typically uses aggregate (i.e., national) level data to estimate total factor productivity and has ignored the technical efficiency component of productivity. The econometric results suggest that stochastic frontier models generate higher mean technical efficiency estimates than deterministic models, while parametric frontier models yield lower estimates than nonparametric. The difference between parametric and non-parametric frontiers is reduced when the translog specification is used. Also, frontier models using cross-sectional data produce lower estimates than those based on panel data. The econometric results also suggest that low-income countries (LICs) present a lower mean technical efficiency than high-income countries (HICs). A more detailed analysis reveals that Western European countries and Australia present, on average, the highest levels of mean technical efficiency among all regions after accounting for some methodological features of the studies. Eastern European countries exhibit the lowest estimate followed by Asian and African countries, while studies from Latin America and Caribbean countries, and from North American countries are in an intermediate position.Farm Management,
Gestión institucional y calidad de servicio en docentes del nivel secundaria de un colegio público de Huaral - 2022
En esta investigación se buscó determinar la relación entre gestión institucional
y la calidad de servicio en docentes de secundaria de una entidad educativa de
Huaral; para ello, se realizó una investigación de tipo aplicada, con un enfoque
cuantitativo, diseño no experimental y de alcance correlacional. Tomándose en
cuenta a 70 docentes como población total, aplicándoles cuestionarios según las
variables en estudio; así para gestión institucional un instrumento de 23 ítems y
para la otra variable, calidad de servicio, fue de 22 ítems. Según los resultados,
el 53% de los docentes dan cuenta que la gestión institucional está considerado
en un nivel bueno y solo un 6% en un nivel bajo; también se puede manifestar
que, para la calidad de servicio, un 56% de los encuestados lo consideran en un
nivel alto, solo un 9% en nivel bajo. Además, habiéndose aplicado la prueba de
correlación de Spearman entre variables en estudio, se puede afirmar la
existencia de una correlación de 0,891, significando ello, una correlación positiva
muy fuerte, por lo que se concluye que existe una relación entre la gestión
institucional y la calidad de servicio en una institución educativa del nivel
secundaria de Huara
Dual Role of p53 in Innate Antiviral Immunity
Tumor suppressor p53 is widely known as ‘the guardian of the genome’ due to its ability to prevent the emergence of transformed cells by the induction of cell cycle arrest and apoptosis. However, recent studies indicate that p53 is also a direct transcriptional target of type I interferons (IFNs) and thus, it is activated by these cytokines upon viral infection. p53 has been shown to contribute to virus-induced apoptosis, therefore dampening the ability of a wide range of viruses to replicate and spread. Interestingly, recent studies also indicate that several IFN-inducible genes such as interferon regulatory factor 9 (IRF9), IRF5, IFN-stimulated gene 15 (ISG15) and toll-like receptor 3 (TLR3) are in fact, p53 direct transcriptional targets. These findings indicate that p53 may play a key role in antiviral innate immunity by both inducing apoptosis in response to viral infection, and enforcing the type I IFN response, and provide a new insight into the evolutionary reasons why many viruses encode p53 antagonistic proteins
ColoLipidGene: Signature of lipid metabolism-related genes to predict prognosis in stage-II colon cancer patients
Lipid metabolism plays an essential role in carcinogenesis due to the requirements
of tumoral cells to sustain increased structural, energetic and biosynthetic precursor
demands for cell proliferation. We investigated the association between expression
of lipid metabolism-related genes and clinical outcome in intermediate-stage colon
cancer patients with the aim of identifying a metabolic profile associated with greater
malignancy and increased risk of relapse. Expression profile of 70 lipid metabolismrelated
genes was determined in 77 patients with stage II colon cancer. Cox regression
analyses using c-index methodology was applied to identify a metabolic-related
signature associated to prognosis. The metabolic signature was further confirmed in
two independent validation sets of 120 patients and additionally, in a group of 264
patients from a public database. The combined analysis of these 4 genes, ABCA1,
ACSL1, AGPAT1 and SCD, constitutes a metabolic-signature (ColoLipidGene) able to
accurately stratify stage II colon cancer patients with 5-fold higher risk of relapse with
strong statistical power in the four independent groups of patients. The identification
of a group of 4 genes that predict survival in intermediate-stage colon cancer patients
allows delineation of a high-risk group that may benefit from adjuvant therapy, and
avoids the toxic and unnecessary chemotherapy in patients classified as low-risk groupThis work was supported by Ministerio de Ciencia e
Innovación del Gobierno de España (Plan Nacional I + D +
i AGL2013–48943-C2–2-R and IPT-2011–1248-060000),
Comunidad de Madrid (P2013/ABI-2728. ALIBIRDCM)
and European Union Structural Funds. CIBEREHD
is funded by the Instituto de Salud Carlos III. This is a
collaborative study between the Molecular Oncology Unit
of The Institute of Advanced Studies of Madrid IMDEA Food
and the Grupo Español Multidisciplinar en Cáncer
Digestivo (GEMCAD
Grain-Size-Induced Collapse of Variable Range Hopping and Promotion of Ferromagnetism in Manganite La0.5Ca0.5MnO3
mong transition metal oxides, manganites have attracted significant attention because of colossal magnetoresistance (CMR)- a magnetic field-induced metal–insulator transition close to the Curie temperature. CMR is closely related to the ferromagnetic (FM) metallic phase which strongly competes with the antiferromagnetic (AFM) charge ordered (CO) phase, where conducting electrons localize and create a long range order giving rise to insulator-like behavior. One of the major open questions in manganites is the exact origin of this insulating behavior. Here we report a dc resistivity and magnetization study on manganite La1−xCaxMnO3 ceramic samples with different grain size, at the very boundary between CO/AFM insulating and FM metallic phases x = 0.5. Clear signatures of variable range hopping (VRH) are discerned in resistivity, implying the disorder-induced (Anderson) localization of conducting electrons. A significant increase of disorder associated with the reduction in grain size, however, pushes the system in the opposite direction from the Anderson localization scenario, resulting in a drastic decrease of resistivity, collapse of the VRH, suppression of the CO/AFM phase and growth of an FM contribution. These contradictory results are interpreted within the standard core-shell model and recent theories of Anderson localization of interacting particles
A multi-targeted approach to suppress tumor-promoting inflammation
Cancers harbor significant genetic heterogeneity and patterns of relapse following many therapies are due to evolved resistance to treatment. While efforts have been made to combine targeted therapies, significant levels of toxicity have stymied efforts to effectively treat cancer with multi-drug combinations using currently approved therapeutics. We discuss the relationship between tumor-promoting inflammation and cancer as part of a larger effort to develop a broad-spectrum therapeutic approach aimed at a wide range of targets to address this heterogeneity. Specifically, macrophage migration inhibitory factor, cyclooxygenase-2, transcription factor nuclear factor-κB, tumor necrosis factor alpha, inducible nitric oxide synthase, protein kinase B, and CXC chemokines are reviewed as important antiinflammatory targets while curcumin, resveratrol, epigallocatechin gallate, genistein, lycopene, and anthocyanins are reviewed as low-cost, low toxicity means by which these targets might all be reached simultaneously. Future translational work will need to assess the resulting synergies of rationally designed antiinflammatory mixtures (employing low-toxicity constituents), and then combine this with similar approaches targeting the most important pathways across the range of cancer hallmark phenotypes
Mitochondrial physiology
As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery
Mitochondrial physiology
As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery
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