Estimating soil seed bank characteristics in ponderosa pine forests using vegetation and forest-floor data

Soil seed banks are important for vegetation management because they contain propagules of species that may be considered desirable or undesirable for site colonization after management and disturbance events. Knowledge of seed bank size and composition before planning management activities facilitates proactive management by providing early alerts of exotic species presence and of abilities of seed banks to promote colonization by desirable species. We developed models in ponderosa pine (Pinus ponderosa) forests in northern Arizona to estimate the size and richness of mineral soil seed banks using readily observable vegetation and fores-floor characteristics. Regression models using three or fewer predictors explained 41 to 59 percent of the variance in 0- to 2-inch (0- to 5-cm) seed densities of total and native perennial seed banks. Key predictors included aboveground plant species richness/10.8 ft2 (1 m2), litter weight and thickness, and tree canopy type (open or closed). Both total and native perennial seed banks were larger and richer in plots containing: (1) species-rich understories, (2) sparse litter, and (3) tree canopy openings. A regression tree model estimated that seed bank density of native perennials is 14-fold greater if aboveground plant richness exceeds eight species/10.8 ft2, forest-floor leaf litter is < 1 inch (2.5 cm) thick, and tree canopies are open

Canopy-tree influences along a soil parent material gradient in Pinus-ponderosa-Quercus gambelii forests, northern Arizona

ABELLA, S. R. (Public Lands Institute and School of Life Sciences, University of Nevada, Las Vegas, Las Vegas, NV 89154-2040) AND J. D. SPRINGER (Ecological Restoration Institute, Northern Arizona University, Flagstaff, AZ 86011-5017). Canopy-tree influences along a soil parent material gradient in Pinus ponderosa- Quercus gambelii forests, northern Arizona. J. Torrey Bot. Soc. 135: 26–36. 2008.—The distribution of canopy trees can impose within-site patterns of soil properties and understory plant composition. At ten sites spanning a soil parent material gradient in northern Arizona Pinus ponderosa-Quercus gambelii forests, we compared soils and plant composition among five canopy types: openings, Pinus ponderosa single trees, Quercus gambelii single stems, dispersed clumps, and thickets. Soil texture on average did not differ significantly among canopy types, whereas Oi horizon thickness and weight, 0–15 cm soil loss-on-ignition, and gravimetric soil moisture differed significantly among three or more canopy types. Understory plant richness per 4 m2 ranged from five species below P. ponderosa to 12 species in openings, with richness below Q. gambelii single stems significantly greater than below Q. gambelii thickets. C4 graminoids (e.g., Aristida purpurea) inhabited openings, while C3 species like Poa fendleriana also occurred below trees. The forbs Thalictrum fendleri and Lathyrus laetivirens were strongly associated with Q. gambelii dispersed clumps and thickets. We also conducted an experimental planting with T. fendleri that was consistent with these correlational results, with outplanted T. fendleri seedling survival 2–7 times greater when planted below Q. gambelii compared to openings. Previous research and our results suggest that understory species associated with Q. gambelii canopies vary regionally, but there are consistently some associated species. Canopy types affected understory vegetation similarly across soil parent materials, not supporting a hypothesis that positive plant interactions changed along soil gradients. Our results suggest that forest management that manipulates both the density and the pattern of trees, together with the growth forms of Q. gambelii trees, can induce within-site spatial patterns of soil properties and understory species

Evaluation of wood basic density as an indirect measurement of the volume of wood raw material

The manufacturing process of wood agglomerate integrates distinct unit that transforms wood raw material into wood agglomerate. The yield of wood agglomerate produced is influenced by the density and the quality of the initial raw material. This work has compared two distinct methodologies aimed at defining the yield of the process through an indirect measurement at the precursor material. Samples (logs of differentiated sizes) were collected immediately at the industry entrance and several parameters were measured. The logs basic density and the moisture content was annotated, through analysis of the corresponding dry and wet mass. Log bark percentage has estimated also at the level of dry and wet basis. These parameters were used to determine the wood volume from different provenance and species in the beginning of the industrial process. The results indicated that wasn’t a great difference between the two different methods to determine the wood basic density and the wood volume in m3. Principal components analysis was used to investigate the differences between different provenances and different species for the wood basic density, and we conclude there is a great variability in wood basic density for the hardwood species than the observed for the softwood and there isn’t a great variability between different provenances. We study too the difference off wood moisture that could be occurring before the evaluation of wood basic density

New findings of Pleistocene fossil turtles (Geoemydidae, Kinosternidae and Chelydridae) from Santa Elena Province, Ecuador

New Pleistocene fossilized turtle remains from five localities of western Ecuador (Santa Elena Province) are described here. All these shell (carapace and plastron) fossil remains come from the Tablazo Formation and belong to three different lineages of cryptodires ("hidden-necked" turtles). The most abundant remains belong to geoemydids, attributed here to the genus Rhinoclemmys (indeterminate species). Less abundant in occurrence are the kinosternidids, attributed to Kinosternon (indeterminate species), and the first fossil record of chelydrids, Chelydra (indeterminate species), in the entirety of Central and South America

COVID-19: Open-data resources for monitoring, modeling, and forecasting the epidemic

We provide an insight into the open-data resources pertinent to the study of the spread of the Covid-19 pandemic and its control. We identify the variables required to analyze fundamental aspects like seasonal behavior, regional mortality rates, and effectiveness of government measures. Open-data resources, along with data-driven methodologies, provide many opportunities to improve the response of the different administrations to the virus. We describe the present limitations and difficulties encountered in most of the open-data resources. To facilitate the access to the main open-data portals and resources, we identify the most relevant institutions, on a global scale, providing Covid-19 information and/or auxiliary variables (demographics, mobility, etc.). We also describe several open resources to access Covid-19 datasets at a country-wide level (i.e., China, Italy, Spain, France, Germany, US, etc.). To facilitate the rapid response to the study of the seasonal behavior of Covid-19, we enumerate the main open resources in terms of weather and climate variables. We also assess the reusability of some representative open-data sources

Tumor Malignancy Characterization in Clinical Environments: An Approach Using the FYC-Index of Spiculation and Artificial Intelligence

According to the World Health Organization, cancer is the second leading cause of death in the world. The myriad of variations, paths of development, and mutations make this abnormality challenging to treat. With the advent of medical imaging, complex qualitative information is collected with the aim of characterizing the pathology; however, the uncomfortable and time-consuming histology remains the state of care within hospitals. This manuscript presents a strategy to extract quantifiable features from the images. The method captures shape perturbation as variations in reference to a perfect circle that is used in a standardized dimensional space. A multifeatured scheme is created when the quantification is applied in all slices produced by imaging modalities such as computed tomography, magnetic resonance imaging, and tomosynthesis. Later, the numbers obtained by the introduced algorithm are used in an artificial intelligence pipeline that correlates spicularity with aggressiveness using the histology as supervising factor

Using a terrestrial ecosystem survey to estimate the historical density of ponderosa pine trees

Maps of historical tree densities for project areas and landscapes may be useful for a variety of management purposes such as determining site capabilities and planning forest thinning treatments. We used the U.S. Forest Service Region 3 terrestrial ecosystem survey in a novel way to determine if the ecosystem classification is a useful a guide for estimating historical (1880) ponderosa pine (Pinus ponderosa) tree densities on a northern Arizona landscape. Based on sampling 53 sites spanning 9 ecosystem types, we grouped the types into low and high density categories. Tree density was less than 24/ acre on 91 percent (21 of 23) of sites in cinder, dry limestone, and clay basalt ecosystems. In contrast, 70 percent (21 of 30) of sites that contained densities exceeding 24 trees/acre were in basalt, mixed igneous, and moist limestone ecosystems

Estudio de la calidad del árido reciclado y su relación con la resistencia a compresión del hormigón reciclado utilizando una base de datos

This work studies the physical and mechanical properties of recycled concrete aggregate (recycled aggregate from concrete waste) and their influence in structural recycled concrete compressive strength. For said purpose, a database has been developed with the experimental results of 152 works selected from over 250 international references. The processed database results indicate that the most sensitive properties of recycled aggregate quality are density and absorption. Moreover, the study analyses how the recycled aggregate (both percentage and quality) and the mixing procedure (pre-soaking or adding extra water) influence the recycled concrete strength of different categories (high or low water to cement ratios). When recycled aggregate absorption is low (under 5%), pre-soaking or adding extra water to avoid loss in workability will negatively affect concrete strength (due to the bleeding effect), whereas with high water absorption this does not occur and both of the aforementioned correcting methods can be accurately employed.El estudio analiza las propiedades físico-mecánicas de los áridos reciclados de hormigón (procedentes de residuos de hormigón) y su influencia en la resistencia a compresión del hormigón reciclado estructural. Para ello se ha desarrollado una base de datos con resultados de 152 trabajos seleccionados a partir de más de 250 referencias internacionales. Los resultados del tratamiento de la base indican que densidad y absorción son las propiedades más sensibles a la calidad del árido reciclado. Además, este estudio analiza cómo el árido reciclado (porcentaje y calidad) y el procedimiento de mezcla (presaturación o adición de agua extra) influyen en la resistencia del hormigón reciclado de diferentes categorías (alta o baja relación agua-cemento). Cuando la absorción es baja (inferior al 5%) presaturar o añadir agua para evitar pérdidas de trabajabilidad afectan negativamente a la resistencia (debido al bleeding), mientras que cuando es alta esto no sucede y ambos métodos son adecuados

Se and I status in pregnant ewes from a pastoral system and the effect of supplementation with Se and I or only Se on wool quality of lambs

Australian Merino ewes and lambs producing fine fibre wool for export are raised in the north-west of Uruguay in pasture-based systems. We studied the status of selenium and iodine in pregnant Merino ewes (10 per treatment) grazing in natural pasture, in natural pasture and supplemented with Se (0.1 mg Se/kg dry matter intake) and I (1 mg I/kg dry matter intake), or in natural pasture and supplemented with Se alone (0.1 mg Se/kg dry matter intake), during the last 30 days of gestation. Further, we evaluated the performance and wool quality of their offspring. Content of Se and I in natural pasture, in the sera of pregnant ewes, and in the wool of their offspring and levels of thyroidal hormones—TSH, T4, and free T3 (FT3)—in the sera of pregnant ewes were determined. The performance of lambs and the commercial parameters of fine fibre wool produced were measured. Results showed normal Se levels in serum (0.12–0.15 mg/l) in the ewes grazing in natural pasture (0.07–0.09 mg/kg DM) during late pregnancy. The observed increase in Se content in the pasture at lambing (0.11–0.16 mg/kg DM) improved serum Se levels (0.216 mg/l); however, the serum levels were not affected by the supplementation. I content in pasture showed adequate levels (0.50–0.60 mg/kg DM), which were reflected in the blood serum values 30 days prior to lambing (0.197–0.208 mg/l). However, at lambing, the I content in blood serum decreased (0.150 mg/l). Further, the supplementation did not modify the serum I levels (0.163–0.175 mg/l). An increase in FT3 levels in ewes at lambing could be associated with the increase in Se content in pasture and/or the adequate I content in pasture. No effect of supplementation was observed. Lambs showed good results regarding the quality of fine fibre wool and performance after supplementation with Se and I or Se alone and exhibited slightly improved Se and I content in wool. In conclusion, natural pasture provides adequate status in Se and I for the Merino ewes and their offspring without any additional beneficial effects of supplementation with Se and I or only Se