If Watersheds Spoke: A condition analysis of the Rio Tomebamba watershed in southern Ecuador using GIS analysis

Understanding processes and ecological threats occurring at the watershed level scale composes a critical piece of water resource conservation and management. This proves doubly true in areas such as the Ecuadorian highlands where water resources depend heavily on the hydrologic regulation capacities of páramo soils. This study examined watershed condition of the Rio Tomebamba watershed and existing habitat for Metallura baroni and Chibchanomys orcesi, two highly endemic species, within its boundaries. Watershed condition was determined based on a simple index that considered nine indicators of watershed health—converted land, impacted riparian zones, impermeable surfaces, water quality, fluvial habitat condition, riparian vegetation condition, macroinvertebrate community composition, road density, and erosion potential—in four analysis regions of the Rio Tomebamba watershed. Data spanning a five-year period (2015-2019) were analyzed using ArcGIS Pro software. Cultivated pasture was the most common converted land type across all analysis regions, composing 5.8% of the entire Rio Tomebamba watershed. In general watershed condition was highest in the Llaviucu analysis region and lowest in the Lower Tomebamba analysis region. No analysis region, including the Llaviucu region which is protected almost entirely by the Cajas National Park boundary, received an “excellent” condition rating. The Rio Tomebamba watershed as a whole was determined to be in “acceptable” condition. The results showed that riparian corridor degradation posed the most concern across all analysis regions within the watershed. Conservation and restoration of such areas would provide critical habitat for Chibchanomys orcesi, a highly endemic water mouse, and serve as an effective long-term management strategy for the area’s water resources. El conocimiento de los procesos y amenazas ocurriendo al nivel de la cuenca es bastante importante para la gestión y conservación de los recursos de agua, especialmente en las regiones altas de Ecuador donde estos recursos dependen de la regulación hídrica de los suelos de páramo. Esta investigación consideró la condición de la cuenca de Rio Tomebamba y el hábitat que existe para Metallura baroni y Chibchanomys orcesi, dos especies endémicas, dentro de la cuenca. La condición de la cuenca se determinó por un índice simple, considerando nueve indicadores de la de una cuenca: tierra reconvertida, zonas de riberas impactadas, superficies impermeables, la calidad de agua, la condición de hábitat fluvial, la condición de vegetación ribereña, la composición de las comunidades de macroinvertebrados, la densidad de los caminos, y la potencia de erosión hídrica. Estos indicadores y el hábitat de las dos especies endémicas se analizaron sobre cuatro regiones dentro de la cuenca de Rio Tomebamba, usando ArcGIS Pro. Pasto cultivado fue el tipo de tierra reconvertida más común en todas las cuatro regiones y compuso 5.8% de la cuenca total. En general, la condición de la cuenca fue más alta en la región de Llaviucu y más baja en la región de Lower Tomebamba que en el resto de la cuenca. Ninguna de las regiones recibió una nota de condición excelente . La cuenca de Rio Tomebamba se determinó en condición aceptable. Los resultados demostraron que los corredores ribereños están en peor condición de los indicadores sobre todas las regiones de la cuenca. La conservación y restauración de estas áreas proveería hábitat importante para Chibchanomys orcesi, un ratón endémico de agua, y podría servir como una estrategia de gestión efectiva para los recursos de agua del área

Exhaustive enumeration unveils clustering and freezing in random 3-SAT

We study geometrical properties of the complete set of solutions of the random 3-satisfiability problem. We show that even for moderate system sizes the number of clusters corresponds surprisingly well with the theoretic asymptotic prediction. We locate the freezing transition in the space of solutions which has been conjectured to be relevant in explaining the onset of computational hardness in random constraint satisfaction problems.Comment: 4 pages, 3 figure

Novel insights in cryptic diversity of snow and glacier ice algae communities combining 18S rRNA gene and ITS2 amplicon sequencing

Melting snow and glacier surfaces host microalgal blooms in polar and mountainous regions. The aim of this study was to determine the dominant taxa at the species level in the European Arctic and the Alps. A standardized protocol for amplicon metabarcoding using the 18S rRNA gene and ITS2 markers was developed. This is important because previous biodiversity studies have been hampered by the dominance of closely related algal taxa in snow and ice. Due to the limited resolution of partial 18S rRNA Illumina sequences, the hypervariable ITS2 region was used to further discriminate between the genotypes. Our results show that red snow was caused by the cosmopolitan Sanguina nivaloides (Chlamydomonadales, Chlorophyta) and two as of yet undescribed Sanguina species. Arctic orange snow was dominated by S. aurantia, which was not found in the Alps. On glaciers, at least three Ancylonema species (Zygnematales, Streptophyta) dominated. Golden-brown blooms consisted of Hydrurus spp. (Hydrurales, Stramenophiles) and these were mainly an Arctic phenomenon. For chrysophytes, only the 18S rRNA gene but not ITS2 sequences were amplified, showcasing how delicate the selection of eukaryotic ‘universal’ primers for community studies is and that primer specificity will affect diversity results dramatically. We propose our approach as a ‘best practice’

Comparative marine biodiversity and depth zonation in the Southern Ocean: evidence from a new large polychaete dataset from Scotia and Amundsen seas

Based on a dataset of 16,991 and 307 morphospecies of polychaete worms collected from 58 epibenthic sledge deployments across the Scotia and Amundsen Seas, we show that the structures of their shelf, deep-shelf and slope communities are composed of distinct polychaete assemblages spanning regions with “high”, “intermediate”, and “low” biodiversity. Depth has been identified as the main factor structuring the polychaete communities in both seas, countering the prevalent notion of extended eurybathy of the Southern Ocean benthos. From an evolutionary perspective, this strong dissimilarity between shelf and slope fauna could be interpreted as evidence for survival in shelf refugias, rather than migration into deeper waters during glacial maxima. The previously unsampled Amundsen Sea is shown to be diverse, harbouring a high level of taxonomic novelty, with many species new to science. The polychaete community of the inner shelf in the Amundsen Sea (Pine Island Bay) has also been shown to be of deep-sea character, likely due to intrusion of the Circumpolar Deep Water onto the shelf. In the Scotia Sea, our data support the notion of relatively high biodiversity of waters around the South Orkney Islands, South Georgia, and Shag Rocks (all recently established as Marine Protected Areas) and depressed diversity in the extreme environment of Southern Thule

Histidine residue 252 of the Photosystem II D1 polypeptide is involved in a light-induced cross-linking of the polypeptide with the α subunit of cytochrome b-559: study of a site-directed mutant of Synechocystis PCC 6803

AbstractProperties of the Photosystem II (PSII) complex were examined in the wild-type (control) strain of the cyanobacterium Synechocystis PCC 6803 and its site-directed mutant D1-His252Leu in which the histidine residue 252 of the D1 polypeptide was replaced by leucine. This mutation caused a severe blockage of electron transfer between the PSII electron acceptors QA and QB and largely inhibited PSII oxygen evolving activity. Strong illumination induced formation of a D1–cytochrome b-559 adduct in isolated, detergent-solubilized thylakoid membranes from the control but not the mutant strain. The light-induced generation of the adduct was suppressed after prior modification of thylakoid proteins either with the histidine modifier platinum-terpyridine-chloride or with primary amino group modifiers. Anaerobic conditions and the presence of radical scavengers also inhibited the appearance of the adduct. The data suggest that the D1–cytochrome adduct is the product of a reaction between the oxidized residue His252 of the D1 polypeptide and the N-terminal amino group of the cytochrome α subunit. As the rate of the D1 degradation in the control and mutant strains is similar, formation of the adduct does not seem to represent a required intermediary step in the D1 degradation pathway

Low-temperature UV photoluminescence of ion beam synthesized Si nanoclusters embedded in Si

Ultraviolet (UV) photoluminescence (PL) data taken on a double Au implanted Si matrix are reported. This has been studied over a wide temperature range of 28-220 K. At low temperature, the spectrum shows four peaks corresponding to a zero-phonon line (ZP

No spin glass phase in ferromagnetic random-field random-temperature scalar Ginzburg-Landau model

Krzakala, Ricci-Tersenghi and Zdeborova have shown recently that the random field Ising model with non-negative interactions and arbitrary external magnetic field on an arbitrary lattice does not have a static spin glass phase. In this paper we generalize the proof to a soft scalar spin version of the Ising model: the Ginzburg-Landau model with random magnetic field and random temperature-parameter. We do so by proving that the spin glass susceptibility cannot diverge unless the ferromagnetic susceptibility does.Comment: 9 page

DNA barcoding uncovers cryptic diversity in 50% of deep-sea Antarctic polychaetes

The Antarctic marine environment is a diverse ecosystem currently experiencing some of the fastest rates of climatic change. The documentation and management of these changes requires accurate estimates of species diversity. Recently, there has been an increased recognition of the abundance and importance of cryptic species, i.e. those that are morphologically identical but genetically distinct. This article presents the largest genetic investigation into the prevalence of cryptic polychaete species within the deep Antarctic benthos to date. We uncover cryptic diversity in 50% of the 15 morphospecies targeted through the comparison of mitochondrial DNA sequences, as well as 10 previously overlooked morphospecies, increasing the total species richness in the sample by 233%. Our ability to describe universal rules for the detection of cryptic species within polychaetes, or normalization to expected number of species based on genetic data is prevented by taxon-specific differences in phylogenetic outputs and genetic variation between and within potential cryptic species. These data provide the foundation for biogeographic and functional analysis that will provide insight into the drivers of species diversity and its role in ecosystem function

MOTION ARTIFACT CANCELLATION IN AMBULATORY ECG MEASUREMENT SYSTEM FOR THE DETECTION OF CARDIAC DISEASES

Abstract-In this work, a simple and efficient artifact cancellation in ambulatory ECG using adaptive filter is designed for the detection of different cardiac diseases like bradycardia, tachycardia, left ventricular hypertrophy and right ventricular hypertrophy. Our work is focused on extraction of noise free ECG signal and the real-time implementation of artifacts removal techniques. As ECG signal is very sensitive in nature, and even if small noise mixed with original signal the various characteristics of the signal changes, data corrupted with noise must either filtered or discarded, filtering is important issue for design consideration of real-time ECG measurement systems. Here we have implemented different adaptive filtering algorithms (LMS-Least Mean Square, RLS-Recursive Least Squares) using virtual instrumentation technique to minimize the noisy components and to analyze different cardiac diseases like bradycardia, tachycardia, left ventricular hypertrophy and right ventricular hypertrophy. Finally the overall performance of LMS and RLS algorithm is also compared according to the error signal generated by the techniques

Absolute instruments and perfect imaging in geometrical optics

We investigate imaging by spherically symmetric absolute instruments that provide perfect imaging in the sense of geometrical optics. We derive a number of properties of such devices, present a general method for designing them and use this method to propose several new absolute instruments, in particular a lens providing a stigmatic image of an optically homogeneous region and having a moderate refractive index range.Comment: 20 pages, 9 image