Spatial variability of soil erodibility in pastures and forest areas in the municipality of Porto Velho, Rondônia

“Erodibility” is a characteristic of the soil that represents the susceptibility with which its particles from the most superficial layer are taken and transported to lower places by erosive agents, causing environmental and economic damages. This work estimated soil erodibility in pastures and forest areas in the municipality of Porto Velho-Rondônia. In the field, three areas with different types of vegetation were selected, one with brachiaria, another with mombaça grass, and a third in native forest. In areas with pastures, a sampling mesh of equal sizes was outlined (90 m x 60 m), and in the forested area an approximate sampling mesh (90 m x 50 m), with a regular spacing of 10 m between the samples points for both areas. The sampling was done at the crossing points of the mesh at a depth of 0.0-0.2 m, composing 70 sample points in the areas with pastures and 60 sample points in the forest area, totaling 200 samples. Then, laboratory analyzes were carried out to determine the texture followed by the fractionation of the sand, and the organic carbon followed by the estimate of the organic matter of the soil. The erodibility factors were calculated using indirect prediction models, and then, univariate, geostatistical and multivariate techniques were applied. The pastures’ environments differed from the forest environment. However, the mombaça grass area functions as an intermediate environment between the forest and the brachiaria, being closer to the forest environment. Keywords: erodibility, factors, kriging, principal components.

A new automated tool to quantify nucleoid distribution within mitochondrial networks

Mitochondrial DNA (mtDNA) maintenance is essential to sustain a functionally healthy population of mitochondria within cells. Proper mtDNA replication and distribution within mitochondrial networks are essential to maintain mitochondrial homeostasis. However, the fundamental basis of mtDNA segregation and distribution within mitochondrial networks is still unclear. To address these questions, we developed an algorithm, Mitomate tracker to unravel the global distribution of nucleoids within mitochondria. Using this tool, we decipher the semi-regular spacing of nucleoids across mitochondrial networks. Furthermore, we show that mitochondrial fission actively regulates mtDNA distribution by controlling the distribution of nucleoids within mitochondrial networks. Specifically, we found that primary cells bearing disease-associated mutations in the fission proteins DRP1 and MYH14 show altered nucleoid distribution, and acute enrichment of enlarged nucleoids near the nucleus. Further analysis suggests that the altered nucleoid distribution observed in the fission mutants is the result of both changes in network structure and nucleoid density. Thus, our study provides novel insights into the role of mitochondria fission in nucleoid distribution and the understanding of diseases caused by fission defects.

Mitochondrial fission is required for proper nucleoid distribution within mitochondrial networks

Mitochondrial DNA (mtDNA) maintenance is essential to sustain a functionally healthy population of mitochondria within cells. Proper mtDNA replication and distribution within mitochondrial networks are essential to maintain mitochondrial homeostasis. However, the fundamental basis of mtDNA segregation and distribution within mitochondrial networks is still unclear. To address these questions, we developed an algorithm, Mitomate tracker to unravel the global distribution of nucleoids within mitochondria. Using this tool, we decipher the semi-regular spacing of nucleoids across mitochondrial networks. Furthermore, we show that mitochondrial fission actively regulates mtDNA distribution by controlling the distribution of nucleoids within mitochondrial networks. Specifically, we found that primary cells bearing disease-associated mutations in the fission proteins DRP1 and MYH14 show altered nucleoid distribution, and acute enrichment of enlarged nucleoids near the nucleus. Further analysis suggests that the altered nucleoid distribution observed in the fission mutants is the result of both changes in network structure and nucleoid density. Thus, our study provides novel insights into the role of mitochondria fission in nucleoid distribution and the understanding of diseases caused by fission defects.

Fragmented Aurora-like Emissions (FAEs) as a new type of aurora-like phenomenon

This study analyses the observations of a new type of small-scale aurora-like feature, which is further referred to as Fragmented Aurora-like Emission(s) (FAEs). An all-sky camera captured these FAEs on three separate occasions in 2015 and 2017 at the Kjell-Henriksen Observatory near the arctic town of Longyearyben, Svalbard. A total of 305 FAE candidates were identified with varying degrees of certainty. They seem to appear in two categories – randomly occurring individual FAEs and wave-like structures with regular spacing between FAEs alongside auroral arcs. FAEs show horizontal sizes typically below 20 km, a lack of field-aligned emission extent and short lifetimes of less than a minute. Emissions were observed at the 557.7 nm line of atomic oxygen and at 673.0 nm (N2, first positive band system), but not at the 427.8 nm emission of N2+ or the 777.4 nm line of atomic oxygen. This suggests a limit to the energy of the generating mechanism. Their lack of field-aligned extent indicates a different generation mechanism than for aurora, which is caused by particle precipitation. Instead, these FAEs could be the result of excitation by thermal ionospheric electrons. FAE observations are seemingly accompanied by elevated electron temperatures between 110–120 km and increased ion temperatures at F-region altitudes. One possible explanation for this are Farley-Buneman instabilities of strong local currents. We provide an overview of the observations and discuss them as well as potential generation mechanisms in the present study.

A peptide pair coordinates regular ovule initiation patterns with seed number and fruit size

Ovule development in Arabidopsis thaliana involves pattern formation which ensures that ovules are regularly arranged in the pistils to reduce competition for nutrients and space. Mechanisms underlying pattern formation in plants, such as phyllotaxis, flower morphogenesis or lateral root initiation, have been extensively studied, and genes controlling the initiation of ovules have been identified. However, how a regular spacing of ovules is achieved is not known. Using natural variation analysis combined with quantitative trait locus analysis, we found that the spacing of ovules in the developing fruits is controlled by two secreted peptides, EPFL2 and EPFL9 (also known as Stomagen), and their receptors from the ERECTA (ER) family that act from the carpel wall and the placental tissue. We found that a signalling pathway controlled by EPFL9 acting from the carpel wall through the LRR-receptor kinases ER, ERL1 and ERL2 promotes fruit growth. Regular spacing of ovules depends on EPFL2 expression in the carpel wall and in the inter-ovule spaces, where it acts through ERL1 and ERL2. Loss of EPFL2 signalling results in shorter fruits and irregular spacing of ovules or even ovule twinning. The EPFL2 expression pattern between ovules is under negative-feedback regulation by auxin, which accumulates in the arising ovule primordia. We propose that the auxin-EPFL2 signalling module evolved to control the initiation and regular, equidistant spacing of ovule primordia, which serves to minimise competition between developing seeds. Together, EPFL2 and EPFL9 coordinate ovule patterning and thereby seed number with fruit growth through a set of shared receptors.

Sphere-Filling Asymptotics of the Barotropic Potential Vorticity Staircase

For barotropic flow in spherical geometry, the ideal potential vorticity staircase with flat steps and vertical risers exhibits a relationship between prograde jet strength and spacing such that, for regular spacing, the distance between adjacent jets is given by a suitably defined “Rhines scale” multiplied by a positive constant equal to . This result was obtained previously by the author in the equatorial limit of spherical geometry and by others in periodic beta-plane geometry. An improved asymptotic method has been devised to explain the strength–spacing relationship in sphere-filling solutions. This analysis explains the approximate validity of the equatorial asymptotics and yields new insight on minimum energy states and staircase mode transitions simulated in the presence of random, persistent energy inputs at high horizontal wavenumber.

Chaperonin GroEL accelerates protofibril formation and decorates fibrils of the Het-s prion protein

We have studied the interaction of the prototypical chaperonin GroEL with the prion domain of the Het-s protein using solution and solid-state NMR, electron and atomic force microscopies, and EPR. While GroEL accelerates Het-s protofibril formation by several orders of magnitude, the rate of appearance of fibrils is reduced. GroEL remains bound to Het-s throughout the aggregation process and densely decorates the fibrils at a regular spacing of ∼200 Å. GroEL binds to the Het-s fibrils via its apical domain located at the top of the large open ring. Thus, apo GroEL and bullet-shaped GroEL/GroES complexes in which only a single ring is capped by GroES interact with the Het-s fibrils; no evidence is seen for any interaction with football-shaped GroEL/GroES complexes in which both rings are capped by GroES. EPR spectroscopy shows that rotational motion of a nitroxide spin label, placed at the N-terminal end of the first β-strand of Het-s fibrils, is significantly reduced in both Het-s/GroEL aggregates and Het-s fibrils, but virtually completely eliminated in Het-s/GroEL fibrils, suggesting that in the latter, GroEL may come into close proximity to the nitroxide label. Solid-state NMR measurements indicate that GroEL binds to the mobile regions of the Het-s fibril comprising the N-terminal tail and a loop connecting β-strands 4 and 5, consistent with interactions involving GroEL binding consensus sequences located therein.

‘PROCLAIMING IT TO GREEKS AND NATIVES, ALONG THE ROWS OF THE CHEQUER-BOARD’: READERS AND VIEWERS OF ACROSTICH INSCRIPTIONS IN GREEK, DEMOTIC AND LATIN

Hellenistic and Roman acrostich inscriptions are usually full of verbal and visual clues, which point the reader in the direction of the ‘hidden message’ contained in the vertical lines of the text. The authors of such inscriptions want their audiences to appreciate the skill that has gone into their composition. There are several complementary ways in which the presence of an acrostich might be signalled to the reader or viewer and their attention directed towards it. These include direct verbal statements, or more subtle allusions, within the text of the inscription. But, even without having read its text, the viewer of an inscription containing a ‘hidden message’ is often immediately aware that some kind of wordplay is at work. Acrostichs, palindromes and various kinds of word square are all graphically striking, or their appearance may be enhanced to make them more so. Regular spacing, the repetition of the acrostich in a separate column and the use of painted or incised grids are all ways in which the layout of the text on the stone can invite the viewer to play a word game. In some cases, as I will argue in this paper, acrostich makers envisaged—even intended—the participants in this game to include the illiterate as well as the literate.

Distribuição dos agregados em terra preta arqueológica de áreas cultivadas no município de Novo Aripuanã, Amazonas

<p>Em meio à vasta região Amazônica, ocorrem áreas de elevada fertilidade, onde as características originais do solo foram modificadas por processos antrópicos, as Terras Pretas Arqueológicas que apresentam coloração escura e elevada fertilidade natural. Objetivou-se neste trabalho, investigar a distribuição dos agregados no solo em áreas de Terras Pretas Arqueológicas cultivadas com pastagem e feijão guandu na região de Novo Aripuanã, Amazonas. Foram escolhidas duas áreas de terra preta arqueológica sob cultivo de pastagem e feijão guandu na região de Novo Aripuanã, Amazonas. Nesses locais foram estabelecidas malhas de 56 m x 80 m com espaçamento regular de 8 m x 8 m para a área de feijão guandu e de 20 m x 68 m com espaçamento de 5 m x 4 m para a área com pastagem, em seguida foram amostradas nos pontos de cruzamento da malha. Os pontos foram georreferenciado com um equipamento de GPS e em seguida coletadas amostras de solos nas camadas 0,0-0,05 m; 0,05-0,10 m e 0,10 - 0,20 m. Foram determinados as classes de agregados &gt;2 mm, classe de agregados 2-1 mm, diâmetro médio geométrico e diâmetro médio ponderado. Os dados foram utilizados as análises estatísticas e geoestatística. O DMG e DMP foram altos nas áreas sob TPA sob o cultivo de feijão guandu e pastagem, indicando que o solo tem uma boa agregação e apresentaram diferentes alcances em todas as camadas estudadas. As classes de agregados &gt;2 mm e &lt;2 mm apresentaram valores desejáveis e diferentes alcances em todas as camadas estudadas.</p><p align="center"><strong><em>Distribution of households in archaeological black earth of cultivated areas in the municipality of Novo Aripuanã, Amazonas</em></strong></p><p><strong>Abstract: </strong>Amid the vast Amazon region, there are areas of high fertility, where the properties of the soil have been modified by human activity, the Archaeological Dark Earths (ADE) earth that have dark coloration and high natural fertility. The objective of this study was to investigate the distribution of households in the soil in areas of Archaeological Dark Earths cultivated land with pasture and bean in Novo Aripuana region, Amazonas. They were chosen two areas of Archaeological Dark Earths under pasture and bean in the Novo Aripuana region, Amazonas. These sites were established mesh of 56 mx 80 m with regular spacing of 8 mx 8 m for the bean area and 20 mx 68 m with spacing of 5 mx 4 m to the area with pasture, then they were sampled in points cross mesh. The points were georeferenced with a GPS device and then collected samples of soil in layers 0.0-0.05; 0.05-0.10; 0.10 to 0.20 m. Were determined the aggregate classes&gt; 2 mm, 2-1 mm aggregate class, geometric mean diameter and average diameter. The data were used statistical and geostatistical analysis. The ADG and WAD were high in areas under ADE under the bean crop and pasture, indicating that the soil has a good aggregation and showed different ranges in all studied layers. The aggregates classes&gt; 2 mm and &lt;2 mm are desirable values and different ranges in all studied layers.</p>