55,334 research outputs found

    Juniper from Ethiopia contains a large-scale precipitation signal

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    Most semiarid regions are facing an increasing scarcity of woody vegetation due mainly to anthropogenic deforestation aggravated by climate changes. However, there is insufficient information to reconstruct past changes in climate and to evaluate the implications of future climate changes on the vegetation. Tree-ring analysis is a powerful tool for studying tree age, population dynamics, growth behavior, and climate-growth relationships among tropical tree species and for gaining information about the environmental forces driving growth change as well as for developing proxies for climate reconstruction. Wood anatomical and dendrochronological methods were used on Juniperus procera trees from two Ethiopian highland forests to check (i) whether tree-ring series of juniper are cross-datable and hence suitable for building tree-ring chronologies, and if so, (ii) which climate factors mainly drive wood formation in juniper from this region. Visible growth layers of the juniper wood were shown to be annual rings. Tree-ring sequences could be cross-dated between trees growing at the same site and between trees growing at sites 350 km apart. Evidence was found that annual growth of junipers is mainly controlled by one climatic factor, precipitation. This strong precipitation influence proves the potential of African juniper chronologies for accurate climate reconstruction and points out the relevance of building a network of juniper chronologies across East Africa

    Influence of Thyme and Juniper on the Microbiological Properties of Pork Brisket

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    The aim of the work is to determine an influence of non-traditional mixtures of spicy-aromatic plants of thyme and juniper, their essential oils and alcohol extracts on the course of microbiological processes in pork brisket. Pork brisket was an experimental sample. It was added with black pepper, thyme and juniper, in the dry condition, as essential oils and alcohol extracts. Pork brisket, added with dry plants, essential oils, extracts of black and fragrant pepper, was taken as a control. According to the microbiological studies, it was established, that an exceed of the standard index of the content of mesophilic-aerobic and facultative anaerobic microorganisms (more than 1,0×103 g/CCU) takes place in brisket samples with dry black pepper. And also in samples with thyme and juniper in ratios 0,9:0,7:0,2 and 0,9:0,6:0,3. An exceed of nMAFAM index is also fixed in experiments using essential oils of these spices. It was established, that after 80 min of the experiment, these mixtures remain resistant to spoilage by 20 min longer comparing with using dry black and fragrant pepper. Most intense antibacterial properties relative to the development of microorganisms were observed in experimental samples. It is noticeable in a sample with using dry comminuted spices thyme and juniper in ratios 0,9:0,8:0,1. The use of spicy-aromatic plants of thyme and juniper allow to increase the storage term of ready products

    A history of cross-cultural exchanges in Finnish and Swedish diddling

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    Mechanical Removal of Juniper and its Effects on Plant Diversity

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    The increase in density and distribution of juniper (Juniperus spp.) in sagebrush communities throughout the Western United States, primarily as a result of fire suppression and historic over-grazing, has raised concerns among land managers and ranchers due to the detrimental effects of juniper on livestock forage species, and wildlife habitat. Juniper may dominate sagebrush communities because it may decrease understory plant cover and is more proficient in accessing deep soil waters than common competitors in the area. The main objective of this study was to examine how removal of juniper by mechanical means may affect species richness and abundance of forbs in the immediate surrounding area. We estimated species richness and abundance of forbs in three treatments: live juniper, removed juniper (stump present with masticated juniper materials), and non-juniper (no live juniper tree or stump present). Removed juniper sites had 62% more species than live sites (

    Ambient Temperature Influences Diet Selection and Physiology of an Herbivorous Mammal, \u3cem\u3eNeotoma albigula\u3c/em\u3e

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    The whitethroat woodrat (Neotoma albigula) eats juniper (Juniperus monosperma), but the amount of juniper in its diet varies seasonally. We tested whether changes in juniper consumption are due to changes in ambient temperature and what the physiological consequences of consuming plant secondary compounds (PSCs) at different ambient temperatures might be. Woodrats were acclimated to either 20ÂșC or 28ÂșC. Later, they were given two diets to choose from (50% juniper and a nontoxic control) for 7 d. Food intake, resting metabolic rate (RMR), and body temperature (Tb) were measured over the last 2 d. Woodrats at 28ÂșC ate significantly less juniper, both proportionally and absolutely, than woodrats at 20ÂșC. RMRs were higher for woodrats consuming juniper regardless of ambient temperature, and Tb was higher for woodrats consuming juniper at 28ÂșC than for woodrats eating control diet at 28ÂșC. Thus, juniper consumption by N. albigula is influenced by ambient temperature. We conclude that juniper may influence thermoregulation in N. albigula in ways that are helpful at low temperatures but harmful at warmer temperatures in that juniper PSCs may be more toxic at warmer temperatures. The results suggest that increases in ambient temperature associated with climate change could significantly influence foraging behavior of mammalian herbivores

    Regeneration Αnalysis of the Juniperus excelsa Mixed Stands in Prespa National Park of Greece as a Base for the Assessment of the Appropriate Silvicultural Treatment for the Conservation of the Species

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    Analysis of the regeneration of mixed stands of Juniperus excelsa (Greek juniper) in Prespa National Park revealed two distinct structural types: a) stands with small gaps, and b) stands without gaps. Fifteen 500-square-meter sample plots were established in each structural type. All plant species were counted in each plot, and Greek juniper plants were classified into two groups based on their regeneration status. Plants that have been established and grow under the facilitation of other plants fall into the first group, while those that have been established and grow in light, in canopy gaps, belong to the second. Regarding the regeneration of Greek juniper in the Greek juniper mixed stands with small gaps, facilitation is not the primary mechanism at work. There are less Greek juniper regeneration plants in the gap-free structural type, compared with the small-gap type. Greek juniper regeneration plant density will decrease if gaps close. Finally, in both structural types, the other species\u27 regeneration plants exhibit higher density than those of Greek juniper. Creating gaps around Greek juniper trees by extensive intervention is one of the most successful ways for the forest practice to protect the Greek juniper mixed stands

    Mapping and Risk Assessment of Juniper Encroachment Into a Prairie Landscape

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    Juniper encroachment is a considerable threat to the prairie ecosystems of the Great Plains because it has the potential to alter native grasslands by changing soil characteristics, limiting herbaceous biomass, and hindering native community regeneration. Accurate maps of juniper cover and predictions of areas at risk for future expansion are needed to support proactive management measures. Therefore, our objectives are to: (1) Develop a practical workflow for large-scale juniper mapping using Landsat 8 Operational Land Imager (OLI) imagery and partial unmixing techniques, (2) Compare the classification accuracies from the resulting map based on different juniper density thresholds and different types of imagery, (3) Develop a predictive spatial model for the distribution of low-density juniper based on distance to seed source and environmental covariates and determine the prediction accuracy, and (4) Use the resulting maps to evaluate the extent of current juniper establishment and the risk of future encroachment. The study area encompasses counties bordering the Missouri River in southeastern South Dakota and northeastern Nebraska and covering approximately 23,000 km2. We applied a matched filtering technique to classify juniper with snowcovered and snow-free winter imagery (December-March) and snow-free spring imagery (April-June). We found that using the snow-covered winter images suppressed background spectral signatures and resulted in a higher overall classification accuracy of 93.7% for juniper densities above 15 percent, compared to snow-free winter imagery and spring imagery. When characterizing juniper densities below 10 percent our 30-meter pixel level classification map was unreliable, with an 11% probability of correctly classifying juniper. Therefore, we used Random Forests, a machine-learning algorithm, to develop a model of low-density (≀ 15%) juniper based on classified juniper cover and other ecological factors. We used the receiver operating characteristics (ROC) curve to evaluate model predictions; accuracy was high with an area under the curve (AUC) of 0.884. Our susceptibility map indicated that an additional 7.7% of the study area currently contained low densities of juniper and had high to very high risk of future encroachment. This study will provide agencies and land managers with information and techniques needed to address juniper encroachment in the Northern Great Plains

    Response of spectral reflectances and vegetation indices on varying juniper cone densities

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    Juniper trees are widely distributed throughout the world and are common sources of allergies when microscopic pollen grains are transported by wind and inhaled. In this study, we investigated the spectral influences of pollen-discharging male juniper cones within a juniper canopy. This was done through a controlled outdoor experiment involving ASD FieldSpec Pro Spectroradiometer measurements over juniper canopies of varying cone densities. Broadband and narrowband spectral reflectance and vegetation index (VI) patterns were evaluated as to their sensitivity and their ability to discriminate the presence of cones. The overall aim of this research was to assess remotely sensed phenological capabilities to detect pollen-bearing juniper trees for public health applications. A general decrease in reflectance values with increasing juniper cone density was found, particularly in the Green (545-565 nm) and NIR (750-1,350 nm) regions. In contrast, reflectances in the shortwave-infrared (SWIR, 2,000 nm to 2,350 nm) region decreased from no cone presence to intermediate amounts (90 g/m2) and then increased from intermediate levels tothe highest cone densities (200 g/m2). Reflectance patterns in the Red (620-700 nm) were more complex due to shifting contrast patterns in absorptance between cones and juniper foliage, where juniper foliage is more absorbing than cones only within the intense narrowband region of maximum chlorophyll absorption near 680 nm. Overall, narrowband reflectances were more sensitive to cone density changes than the equivalent MODIS broadbands. In all VIs analyzed, there were significant relationships with cone density levels, particularly with the narrowband versions and the two-band vegetation index (TBVI) based on Green and Red bands, a promising outcome for the use of phenocams in juniper phenology trait studies. These results indicate that spectral indices are sensitive to certain juniper phenologic traits that can potentially be used for juniper cone detection in support of public health applications. © 2013 by the authors

    Protective effect of olive and juniper leaves extracts on nephrotoxicity induced by thioacetamide in male mice

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    AbstractThis study, for the first time, evaluates the effect of olive and juniper leaves extracts and their combination on thioacetamide (TAA)-induced nephrotoxicity in male mice. The experimental mice were divided into eight groups. Group 1 was served as control. Group 2 was exposed to TAA. Group 3 was treated with TAA and olive leaves extract. Group 4 was subjected to TAA and juniper leaves extract. Group 5 was exposed to TAA and olive and juniper leaves extracts. Groups 6, 7 and 8 were treated with olive, juniper, and olive and juniper leaves extracts respectively. In mice treated with only TAA, significant increases of blood urea nitrogen and uric acid were observed after six weeks. Moreover, levels of serum creatinine, blood urea nitrogen and uric acid were statistically increased in mice administrated with only TAA for twelve weeks. Insignificant alterations in levels of these haematobiochemical parameters were noted in other treated groups after six and twelve weeks. Histopathological evaluations of renal sections from mice treated with only TAA for twelve weeks showed severe damage of the renal corpuscles. Furthermore, the renal sections from mice treated with TAA and olive leaves extract, TAA and juniper leaves extract, TAA and olive and juniper leaves extracts, olive leaves extract, juniper leaves extract, and olive and juniper leaves extracts showed normal structures. In addition, it is conceivable therefore, that these extracts exhibit protective influences against TAA-induced nephrotoxicity, probably mediated through the antioxidative pathway roles
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