Analysis of the relationship between land surface temperature and wildfire severity in a series of landsat images

The paper assesses spatio-temporal patterns of land surface temperature (LST) and fire severity in the Las Hurdes wildfire of Pinus pinaster forest, which occurred in July 2009, in Extremadura (Spain), from a time series of fifteen Landsat 5 TM images corresponding to 27 post-fire months. The differenced Normalized Burn Ratio (dNBR) was used to evaluate burn severity. The mono-window algorithm was applied to estimate LST from the Landsat thermal band. The burned zones underwent a significant increase in LST after fire. Statistically significant differences have been detected between the LST within regions of burn severity categories. More substantial changes in LST are observed in zones of greater fire severity, which can be explained by the lower emissivity of combustion products found in the burned area and changes in the energy balance related to vegetation removal. As time progresses over the 27 months after fire, LST differences decrease due to vegetation regeneration. The differences in LST and Normalized Difference Vegetation Index (NDVI) values between burn severity categories in each image are highly correlated (r = 0.84). Spatial patterns of severity and post-fire LST obtained from Landsat time series enable an evaluation of the relationship between these variables to predict the natural dynamics of burned areas

The N-Terminal Domain of the Drosophila Retinoblastoma Protein Rbf1 Interacts with ORC and Associates with Chromatin in an E2F Independent Manner

The retinoblastoma (Rb) tumor suppressor protein can function as a DNA replication inhibitor as well as a transcription factor. Regulation of DNA replication may occur through interaction of Rb with the origin recognition complex (ORC).We characterized the interaction of Drosophila Rb, Rbf1, with ORC. Using expression of proteins in Drosophila S2 cells, we found that an N-terminal Rbf1 fragment (amino acids 1-345) is sufficient for Rbf1 association with ORC but does not bind to dE2F1. We also found that the C-terminal half of Rbf1 (amino acids 345-845) interacts with ORC. We observed that the amino-terminal domain of Rbf1 localizes to chromatin in vivo and associates with chromosomal regions implicated in replication initiation, including colocalization with Orc2 and acetylated histone H4.Our results suggest that Rbf1 can associate with ORC and chromatin through domains independent of the E2F binding site. We infer that Rbf1 may play a role in regulating replication directly through its association with ORC and/or chromatin factors other than E2F. Our data suggest an important role for retinoblastoma family proteins in cell proliferation and tumor suppression through interaction with the replication initiation machinery

Comparative characterization of different variants of quantitative chromatographic analysis using external and internal standards

Хроматографический анализ серии характеризуемых и градуировочных двухкомпонентных образцов (растворы аналита и стандарта) позволяет сопоставить возможности и особенности одновременно шести вариантов количественных определений способами внешнего и внутреннего стандарта по критериям точности результатов (значениям случайных и систематических погрешностей). Они включают простейший вариант способа внешнего стандарта (I), модифицированный вариант, предполагающий использование дополнительного стандарта и усреднение не абсолютных, а относительных площадей пиков (II), обычно используемый способ внутреннего стандарта (III) и его модифицированную аналогичным образом версию (IV). Кроме этого рассмотрены два варианта использования гомолога аналита в качестве внутреннего стандарта без учета градуировочных коэффициентов (V) и (VI). Это представляет интерес для оптимизации практических работ по хроматографии и процесса обучения предмету. Требования к дополнительным и внутренним стандартам не идентичны. В качестве дополнительных стандартов можно выбирать любые соединения, как введенные в образцы искусственно, так и уже присутствующие в них, причем точное задание их концентраций не требуется. Необходимо лишь обеспечить их равенство в характеризуемом и градуировочном растворах. Показано, что модифицированные варианты методов внешнего и внутреннего стандартов характеризуются одинаковыми относительными стандартными отклонениями результатов. Показано, что минимальными случайными составляющими погрешностями характеризуются варианты, предполагающие применение дополнительного (II) или внутреннего стандарта (IV) и усреднение отношений площадей пиков целевых аналитов и таких стандартов. Для них же минимальны систематические погрешности определений. Для выявления возможных искажений состава анализируемых образцов, обусловленных частичным испарением летучих компонентов в процессе работы с такими образцами, информативен контроль значений градуировочных коэффициентов.Chromatographic analysis of a series of two-component samples (solutions of a target analyte and a standard) allows simultaneous comparison of the possibilities and features of six variants of quantitative analysis using the external and internal standards techniques according to the criteria of results precision and repeatability (random and systematic errors values). These variants include the simplest version of the external standard method (I); its modified version (II) that implies the application of an additional standard and averaging not the absolute, but relative peak areas; the commonly used version of the internal standard method (III); and its version modified in a similar manner (IV). Besides, two variants of using a homologue of the target analyte as the internal standard without determining the calibration coefficients are considered (V) and (VI). This topic is of interest for optimization of practical works on chromatography and teaching the subject in general. The requirements to the additional and internal standards are not identical. Any compound (both present in the samples or added to them) can be selected as the additional standards, and precise setting of their concentrations is not required. It is only necessary to ensure their equal concentrations in the analyzed and reference solutions. It is shown that the modified versions of the external and internal standard methods are characterized by the equal relative standard deviations of the results. The minimal relative standard deviations of the results are typical for the variants implying the use of an additional (II) or an internal (IV) standard and the averaging the ratio of peak areas of target analytes and such standards. The systematic errors of determinations appeared to be minimal for the same variants. Controlling the values of the calibration coefficients is informative for revealing the possible distortions of the composition of samples due to the partial evaporation of volatile constituents in the course of handling such samples.Практическая работа, результаты которой составили предмет настоящего сообщения, выполнена с использованием оборудования Ресурсного Центра «Методы анализа состава вещества» Санкт-Петербургского государственного университета. Авторы благодарят сотрудников Центра за содействие.The students’ work, which results are discussed in this paper, was carried out at the Center for Chemical and Material Research of St. Petersburg State University’s Research Park. The author is grateful to the staff of this Center for the assistance

Unconscious information changes decision accuracy but not confidence

The controversial idea that information can be processed and evaluated unconsciously to change behavior has had a particularly impactful history. Here, we extend a simple model of conscious decision-making to explain both conscious and unconscious accumulation of decisional evidence. Using a novel dichoptic suppression paradigm to titrate conscious and unconscious evidence, we show that unconscious information can be accumulated over time and integrated with conscious elements presented either before or after to boost or diminish decision accuracy. The unconscious information could only be used when some conscious decision-relevant information was also present. These data are fit well by a simple diffusion model in which the rate and variability of evidence accumulation is reduced but not eliminated by the removal of conscious awareness. Surprisingly, the unconscious boost in accuracy was not accompanied by corresponding increases in confidence, suggesting that we have poor metacognition for unconscious decisional evidence

The dynamics of the tundra-taiga boundary: An overview and suggested coordinated and integrated approach to research

The tundra-taiga boundary stretches for more than 13 400 km around the Northern Hemisphere and is probably the Earth's greatest vegetation transition. The trees that define the boundary have been sensitive to climate changes in the past and models of future vegetation distribution suggest a rapid and dramatic invasion of the tundra by the taiga. Such changes would generate both positive and negative feedbacks to the climate system and the balance could result in a net warming effect. However, the, boundary is becoming increasingly affected by human activities that remove trees and degrade forest-tundra into tundra-like areas. Because of the vastness and remoteness of the tundra-taiga boundary, and of methodological problems such as problematic definitions and lack of standardized methods to record the location and characteristics of the ecotone, a project group has been established under the auspices of the International Arctic Science Committee (IASC). This paper summarizes the initial output of the group and focuses on our uncertainties in understanding the current processes at the tundra-taiga boundary and the conflicts between model predictions of changes in the location of the boundary and contrasting recently observed changes due to human activities. Finally, we present recommendations for a coordinated international approach to the problem and invite the international community to join us in reducing the uncertainties about the dynamics of the ecotone and their consequences.</p

The dynamics of the tundra-taiga boundary: An overview and suggested coordinated and integrated approach to research

The tundra-taiga boundary stretches for more than 13 400 km around the Northern Hemisphere and is probably the Earth's greatest vegetation transition. The trees that define the boundary have been sensitive to climate changes in the past and models of future vegetation distribution suggest a rapid and dramatic invasion of the tundra by the taiga. Such changes would generate both positive and negative feedbacks to the climate system and the balance could result in a net warming effect. However, the, boundary is becoming increasingly affected by human activities that remove trees and degrade forest-tundra into tundra-like areas. Because of the vastness and remoteness of the tundra-taiga boundary, and of methodological problems such as problematic definitions and lack of standardized methods to record the location and characteristics of the ecotone, a project group has been established under the auspices of the International Arctic Science Committee (IASC). This paper summarizes the initial output of the group and focuses on our uncertainties in understanding the current processes at the tundra-taiga boundary and the conflicts between model predictions of changes in the location of the boundary and contrasting recently observed changes due to human activities. Finally, we present recommendations for a coordinated international approach to the problem and invite the international community to join us in reducing the uncertainties about the dynamics of the ecotone and their consequences.</p

Relationship between gene co-expression and sharing of transcription factor binding sites in Drosophila melanogaster

Motivation: In functional genomics, it is frequently useful to correlate expression levels of genes to identify transcription factor binding sites (TFBS) via the presence of common sequence motifs. The underlying assumption is that co-expressed genes are more likely to contain shared TFBS and, thus, TFBS can be identified computationally. Indeed, gene pairs with a very high expression correlation show a significant excess of shared binding sites in yeast. We have tested this assumption in a more complex organism, Drosophila melanogaster, by using experimentally determined TFBS and microarray expression data. We have also examined the reverse relationship between the expression correlation and the extent of TFBS sharing