Defense and Attack Techniques against File-based TOCTOU Vulnerabilities: a Systematic Review

File-based Time-of-Check to Time-of-Use (TOCTOU) race conditions are a well-known type of security vulnerability. A wide variety of techniques have been proposed to detect, mitigate, avoid, and exploit these vulnerabilities over the past 35 years. However, despite these research efforts, TOCTOU vulnerabilities remain unsolved due to their non-deterministic nature and the particularities of the different filesystems involved in running vulnerable programs, especially in Unix-like operating system environments. In this paper, we present a systematic literature review on defense and attack techniques related to the file-based TOCTOU vulnerability. We apply a reproducible methodology to search, filter, and analyze the most relevant research proposals to define a global and understandable vision of existing solutions. The results of this analysis are finally used to discuss future research directions that can be explored to move towards a universal solution to this type of vulnerability. Autho

Secuestro de C en plantaciones de Eucalyptus spp establecidas en terrenos agrícolas en el norte de España

Una de las estrategias que se ha planteado para fijar gases con efecto invernadero (CO2, CH4 y N2O) es el aumento de la superficie forestal. España es uno de los países que más han contribuido a incrementar la superficie forestal en Europa, lo que se debe en buena parte al establecimiento de parcelas en tierras agrarias en situación de marginalidad. Durante el período de 11 años, transcurridos entre el segundo y el tercer inventarios forestales (1987 y 1998), el almacenamiento de C en biomasa arbórea en el norte de España ha aumentado en un 50 %. En este trabajo se realiza una primera estimación de las ganancias de C en biomasa y suelo en plantaciones de eucalipto establecidas en terrenos agrícolas. Para ello se seleccionaron un total de 25 pares de parcelas. Se trata de parcelas agrarias en las cuales parte de la superficie se transformó a plantación de Eucalyptus sp. En estas parcelas se determinó la acumulación de C en biomasa arbórea, mantillo y suelo en tres profundidades 0-5, 5-15 y 15-30 cm. Dado las mejores condiciones de fertilidad y mayor profundidad, que promueven el crecimiento arbóreo, la tasa de acumulación de C en biomasa es considerablemente superior a las plantaciones establecidas en suelos forestales. Los datos de este trabajo muestran acumulaciones superiores a 17 Mg ha-1 año-1. La acumulación de C en el mantillo también es superior a 1 Mg ha-1 año-1. En cuanto al suelo mineral, las pérdidas de C se reducen con los años desde el cambio de uso, fundamentalmente a partir de los 15 años del establecimiento y en plantaciones sobre esquistos y pizarras. Hasta ese momento se produjeron ligeras pérdidas.____________________________________One of the strategies proposed for fixing gases that contribute to the greenhouse effect (CO2, CH4 and N2O) is to increase the extension of land covered by forest. Spain is one of the countries that has contributed most to the increase in the forest area in Europe, largely due to the establishment of forest plots on marginal agricultural land. During the 11- year period between the second and third forest inventories (1987 and 1998), there has been a 50% increase in the storage of C in tree biomass in northern Spain. In the present study, a first estimate was made of the increase in C in biomass and soil in eucalyptus plantations established on agricultural land. A total of 25 pairs of plots were selected for the study. The plots are on agricultural land, part of which has been transformed by plantation of Eucalyptus sp. The amount of C accumulated in the tree biomass, humus and three different depths of soil (0-5, 5-15 and 15-30 cm) was determined. Given the more fertile conditions and the greater depth of the soil, which favour tree growth, the rate of accumulation of C in the biomass was considerably higher than in plantations established on forest soils. The data obtained in the present study revealed accumulations of C of more than 17 Mg ha-1 year-1. Accumulation of C in the humus was also higher than 1 Mg ha-1 year-1. The losses of C in the mineral soil decreased since the change in land use, generally from 15 years after establishment onwards, and in plantations on schists and slates. Slight losses of C were observed up until this time

Reconstructing the origins and the biogeography of species’ genomes in the highly reticulate allopolyploid-rich model grass genus Brachypodium using minimum evolution, coalescence and maximum likelihood approaches

The identification of homeologous genomes and the biogeographical analyses of highly reticulate allopolyploid-rich groups face the challenge of incorrectly inferring the genomic origins and the biogeographical patterns of the polyploids from unreliable strictly bifurcating trees. Here we reconstruct a plausible evolutionary scenario of the diverging and merging genomes inherited by the diploid and allopolyploid species and cytotypes of the model grass genus Brachypodium. We have identified the ancestral Brachypodium genomes and inferred the paleogeographical ranges for potential hybridization events that originated its allopolyploid taxa. We also constructed a comprehensive phylogeny of Brachypodium from five nuclear and plastid genes using Species Tree Minimum Evolution allele grafting and Species Network analysis. The divergence ages of the lineages were estimated from a consensus maximum clade credibility tree using fossil calibrations, whereas ages of origin of the diploid and allopolyploid species were inferred from coalescence Bayesian methods. The biogeographical events of the genomes were reconstructed using a stratified Dispersal-Extinction-Colonization model with three temporal windows. Our combined Minimum Evolution-coalescence-Bayesian approach allowed us to infer the origins and the identities of the homeologous genomes of the Brachypodium allopolyploids, matching the expected ploidy levels of the hybrids. To date, the current extant progenitor genomes (species) are only known for B. hybridum. Putative ancestral homeologous genome have been inherited by B. mexicanum, ancestral and recent genomes by B. boissieri, and only recently evolved genomes by B. retusum and the core perennial clade allopolyploids (B. phoenicoides, B. pinnatum 4x, B. rupestre 4x). We dissected the complex spatio-temporal evolution of ancestral and recent genomes and have detected successive splitting, dispersal and merging events for dysploid homeologous genomes in diverse geographical scenarios that have led to the current extant taxa. Our data support Mid-Miocene splits of the Holarctic ancestral genomes that preceded the Late Miocene origins of Brachypodium ancestors of the modern diploid species. Successive divergences of the annual B. stacei and B. distachyon diploid genomes were implied to have occurred in the Mediterranean region during the Late Miocene-Pliocene. By contrast, a profusion of splits, range expansions and different genome mergings were inferred for the perennial diploid genomes in the Mediterranean and Eurasian regions, with sporadic colonizations and further mergings in other continents during the Quaternary. A reliable biogeographical scenario was obtained for the Brachypodium genomes and allopolyploids where homeologous genomes split from their respective diploid counterpart lineages in the same ancestral areas, showing similar or distinct dispersals. By contrast, the allopolyploid taxa remained in the same ancestral ranges after hybridization and genome doubling events. Our approach should have utility in deciphering the genomic composition and the historical biogeography of other allopolyploid-rich organismal groups, which are predominant in eukaryotes

Contrasting complexing capacity of dissolved organic matter produced during the onset, development and decay of a simulated bloom of the marine diatom Skeletonema costatum

Original research articleThe capacity of natural dissolved organic matter (DOM) produced during the onset, development and decay of a simulated bloom of the marine diatom Skeletonema costatum to complex free copper has been followed for a 2 week period. Copper binding capacity of the culture was measured by anodic stripping voltammetry (ASV) with a hanging mercury drop electrode (HMDE). The concentration of dissolved organic carbon (DOC) and two fluorophores, M (humic-like, Ex/Em: 320 nm/410 nm) and T (protein-like, Ex/Em: 280 nm/350 nm), were followed during the course of the incubation. Models using DOC concentrations alone could not accurately predict the complexing capacity of the culture, especially at the end of the bloom, and better predictions were obtained when fluorescence measurements were considered. They were helpful in characterising two types of copper ligands produced in the culture. The first type, traced by the fluorescence of peak T, was related to labile DOC directly exuded by phytoplankton. The second type, traced by the fluorescence of peak M, was the refractory humic-like material presumably produced in situ as a by-product of the bacterial degradation of phytogenic materials. During the onset and development of the bloom (days 0 to 7), the fluorescence of peak T explains 60–80% of the total complexing capacity of the culture, suggesting that exuded “protein-like” compounds among other exuded complexing agents efficiently complexed free copper. On the contrary, during the decay (days 8 to 13), these ligands were replaced by humic substances as the complexing agent for copper.Financial support for this work came from the Spanish ‘Ministerio de Educación y Ciencia’ (MEC), Grant Nos. REN2000-0880-C02-01 MAR and REN2003-00958 MAR and the ‘Xunta de Galicia’, Grant No. PGIDT01MAR40201PN.Versión del editor2,75

La compatibilidad entre estudios y deporte en estudiantes de secundaria

The purpose of this research was to analysethe difficulties thathigh school studentshadto balance outstudiesandsports. Following adescriptiveexploratorymethodandthroughthe application of atestquestionnaireandconductinga discussion group, informationwascollectedin relation to fourkey factors: the characteristicsof the sport, the conflicts of interestemergedinbalancingstudiesand sport, the support and resources theyhadto bring togetherthisdoubleactivityandthetrainingand professional expectationsthatwereahead of theirfuture. Theanalysis of the differentfactors involved inthe development of thisdouble activity, constitutes afundamentalelement of reference sothatschoolsimplementmeasuresand actions that allow these students to continue with theirsports training, without having to give upeducation. The results obtainedhighlightthe difficulties thathigh school students havetocombineboth processes, which requires them greateffort, good planning ofgoals, appropriate organization of time andpersistenceinachievingthe objectives.La finalidad de esta investigación fue analizar las dificultades que los estudiantes de secundaria tenían para compatibilizar estudios y deportes. Siguiendo un método descriptivo de carácter exploratorio y a través de la aplicación de una prueba de cuestionario y la realización de un grupo de discusión, se recogió información en relación a cuatro factores clave: las características propias de la práctica deportiva, el conflicto de intereses surgido a la hora de compatibilizar los estudios y el deporte, los apoyos y recursos con los que contaban para armonizar esta doble actividad y las expectativas formativas y profesionales que tenían de cara a su futuro. El análisis de los distintos factores que intervienen en el desarrollo de esta doble actividad, constituye un elemento de referencia fundamental para que los centros educativos implanten medidas y acciones que permitan a estos estudiantes continuar con su preparación deportiva, sin tener que renunciar a la formación. Los resultados obtenidos ponen de manifiesto las dificultades que tienen los estudiantes de secundaria para compaginar ambos procesos, lo que les exige un gran esfuerzo, una buena planificación de metas, una adecuada organización del tiempo y persistencia en el logro de los objetivos planteados

El abandono de los estudios universitarios: factores determinantes y medidas preventivas

La deserción de los estudios se ha convertido en un tema importante para la investigación, dado que uno de los retos que tienen plateado la enseñanza universitaria, a nivel mundial, es la puesta en práctica de medidas encaminadas a paliar el efecto negativo de este problema, que afecta de manera directa no sólo a un elevado porcentaje de estudiantes por año, sino también a la propia institución universitaria. En este artículo se presenta una investigación realizada con estudiantes de las 39 titulaciones de la Universidad de La Laguna que habían iniciado sus estudios en el curso 1998-1999, con el objeto de determinar las causas del abandono o prolongación de los estudios. Las variables estudiadas se referían a las características psicoeducativas del alumnado, los hábitos de estudios, las características de la carrera y del profesorado y las características bio-socioeconómicas

Hypertension as a Risk Factor for Hip Fracture

Producción CientíficaArterial hypertension is a chronic disease in which prevalence increases with age, as occurs in osteoporosis. It is clinically silent and is only revealed in the form of complications, an aspect that it also shares with osteoporosis. Various alterations of calcium metabolism have been described in association with hypertension; such alterations can cause decreased bone mass, the principal determining factor of fracture.1,2 Another important factor is the occurrence of falls. Hypertensive patients may experience a greater number of falls resulting from fainting associated with diminished baroreflex sensitivity or hypotension secondary to therapy.3,4 The purpose of this study was to assess the effect of hypertension and its various therapeutic alternatives on the risk of hip fracture.2015-09-0

Sensitivity and representativeness of One-Health surveillance for diseases of zoonotic potential at health facilities relative to household visits in rural Guatemala

Most human and animal disease notification systems are unintegrated and passive, resulting in underreporting. Active surveillance can complement passive efforts, but because they are resource-intensive, their attributes must be evaluated. We assessed the sensitivity and representativeness of One-Health surveillance conducted at health facilities compared to health facilities plus monthly household visits in three rural communities of Guatemala. From September 2017 to November 2018, we screened humans for acute diarrheal, febrile and respiratory infectious syndromes and canines, swine, equines and bovines for syndromic events or deaths. We estimated the relative sensitivity as the incidence rate ratio of detecting an event in health facility surveillance compared to household surveillance from Poisson models. We used interaction terms between the surveillance method and sociodemographic factors or time trends to assess effect modification as a measure of relative representativeness. We used generalized additive models with smoothing splines to model incidence over time by surveillance method. We randomized 216 households to health facility surveillance and 198 to health facility surveillance plus monthly household visits. Health facility surveillance alone was less sensitive than when combined with household surveillance by 0.42 (95% CI: 0.34, 0.53), 0.56 (95% CI: 0.39, 0.79), 0.02 (95% CI: 0.00, 0.10), 0.28 (95% CI: 0.15, 0.50) and 0.22 (95% CI: 0.03, 0.92) times for human acute infections, human severe acute infections, and deaths in canines, swine and equines, respectively. Health facility surveillance alone underrepresented Spanish speakers (interaction p-value = 0.0003) and persons in higher economic assets (interaction p-values = 0.0008). The trend in incidence over time was different between the two study groups, with a larger decrease in the group with household surveillance (all interaction p-values <0.10). Surveillance at health facilities under ascertains syndromes in humans and animals which leads to underestimation of the burden of zoonotic disease. The magnitude of under ascertainment was differentially by sociodemographic factors, yielding an unrepresentative sample of health events. However, it is less time-intensive, thus might be sustained over time longer than household surveillance. The choice between methodologies should be evaluated against surveillance goals and available resources

Pulsational frequencies of the eclipsing delta-Scuti star HD 172189

The eclipsing delta-Scuti star HD 172189 is a probable member of the open cluster IC 4756 and a promising candidate target for the CoRoT mission. The detection of pulsation modes is the first step in the asteroseismological study of the star. Further, the calculation of the orbital parameters of the binary system allows us to make a dynamical determination of the mass of the star, which works as an important constraint to test and calibrate the asteroseismological models. From a detailed frequency analysis of 210 hours of photometric data of HD 172189 obtained from the STEPHI XIII campaign we have identified six pulsation frequencies with a confidence level of 99% and a seventh with a 65% confidence level in the range between 100-300 uHz. In addiction, three eclipses were observed during the campaign, allowing us to improve the determination of the orbital period of the system.Comment: 6 pages, 7 figure