Hasil untuk "Natural history (General)"

Robert Newell, Nina‐Marie Lister, Ann Dale et al.

Abstract Implementing wildlife crossings and restoring landscape connectivity are ecological, social, and economic imperatives. However, in North America, connectivity planning faces challenges associated with governance being fragmented into local jurisdictions and no single agency being solely responsible. Such challenges present a need for tools that can support coordinated actions among different jurisdictions, agencies, and organizations, and effectively promote the importance of landscape connectivity work to diverse audiences. The current study employs a transdisciplinary approach for developing the wildlife crossing database platform (WCDP), a tool for sharing information among practitioners and engaging the public in critical landscape connectivity issues and efforts. The research was conducted in 2 stages: (1) developing a beta version of the WCDP, and (2) engaging diverse practitioners in the field of landscape connectivity to discuss its utility and identify needs for further development. The WCDP was created using Drupal and JavaScript, and it allows users to access, explore, share, and communicate information on wildlife database crossings in North America. A research‐practitioner discussion was convened to discuss the beta version of the WCDP, as well as the key considerations and recommendations for its further development as an effective landscape connectivity planning tool. Data from the researcher‐practitioner discussion were thematically coded and analyzed to reveal 4 major themes with important implications for tool development: (1) differentiate access and functionality between users and the public groups; (2) ensure lessons and success stories are effectively shared; (3) understand the complications and challenges around communicating wildlife crossing information; and (4) recognize landscape connectivity features that do not consist of wildlife crossing infrastructure. Our research produced valuable insights on considerations, challenges, and needs for landscape connectivity work, interprofessional online collaboration, and further refinement of the platform.

Krushna Chandra Das, Aradhana Mohanty, Priyabrat Swain et al.

Market instability, increased competition, escalating price and reduced availability of conventional ingredients warrants the researchers to rely on alternative feed ingredients. This approach may help in producing aqua feeds in a sustainable and cost-effective way to accomplish the global food and nutritional securities. Mahua oil cake (Bassia latifolia) is an underutilized non-conventional ingredient that holds promise for incorporation into aqua feed following nutrient enhancement by solid-state fermentation. A five-month pond feeding trial was carried out to investigate the effects of Sachharomyces cerevisiae and Bacillus subtilis fermented mahua oil cake (MOC) on the production performance, nutrient utilization, digestive capacity, and innate immunological responses of Labeo rohita fingerlings. For this, two iso-nitrogenous feed were formulated and prepared incorporating fermented MOC at different levels i.e. 0 and 40 percentage replacing soybean meal and other feed ingredients and fed to rohu fingerlings of two treatment groups in pond culture for 5 months duration. Improved growth performance, feed conversion ratio, feed intake, protein efficiency ratio and digestive capacity were observed in fish fed diets with 40 percent of fermented MOC compared to control. Innate immune responses parameters (respiratory burst activity, myeloperoxidase, lysozyme and hemaglutination activities) were significantly higher (P < 0.05) in fishes fed with fermented MOC. Therefore, we conclude incorporation of solid state fermented mahua oil cake up to 40% level in diet of L. rohita fingerlings in pond culture without any adverse effects on growth, nutrient utilization and innate immune response.

Elizabeth Colantoni

This paper investigates Sandro Botticelli’s Chart of Hell by drawing on select canti and scenes from Dante Alighieri’s Inferno. The chosen episodes of Hell are examined to determine how Botticelli chose to represent them visually. Throughout this analysis, Botticelli’s knowledge and familiarity of The Divine Comedy and especially Inferno is made clear as he depicts key exchanges and characters whenever possible. Although it is a map, the image created is far from flat and static. This paper argues that Botticelli was able to create movement and narrative in his map. With the continued appearances of Dante the pilgrim and his guide Virgil, viewers are able to keep track of and follow these figures throughout their journey in Hell. Sandro Botticelli’s chart can therefore be interpreted in varying ways: chronologically (following their descent further into Hell, as is narrated in the poem) or all at once (as a visual overview of their journey).

Hui Li, Xuekang Lu, Lin Wang et al.

Most experiments show that gas hydrates are often enriched in C2+ gases relative to the feeding gas source because of fractionation during hydrate crystallization directly from free gases and dissolved gases. However, sediments below and near the base of the gas hydrate stability zone (BGHSZ) in many ocean drilling program (ODP)/International Ocean Discovery Program (IODP) sites are relatively enriched in C2+ hydrocarbon gases, compared with the hydrate-occurring zone above. It is still unclear what kind of process causes the abrupt decreases in C1/C2+ ratios with the depth in headspace gas in sediments around seismic bottom-simulating reflector (BSR) and increasing upward C1/C2 ratios in the hydrate-occurring zone. To test the “dissolution/migration mechanism” and its links to the enrichment of ethane near the BSR and increasing upward C1/C2 ratios in the hydrate-occurring zone, we performed a series of pore-scale experimental observations, simulating the gas dissolution–migration–hydration processes, and investigated the effects of the composition of feeding gases and temperatures on the composition of the hydrate grown under the dissolution–migration mechanism. Hydrates are grown from aqueous fluids supplied by the migration of gases dissolved from the capillary-trapped free gas in a capillary high-pressure optical cell, with different supplying gases (90 mol% CH4 + 10 mol% C2H6, 80 mol% CH4 + 20 mol% C2H6) and a geothermal gradient (temperature from 278.15 to 293.15 K). The gas hydrate structure and composition were determined by quantitative Raman spectroscopy. Our study indicated that (1) under the dissolution–migration–hydration processes, the mole fraction of C2H6 in hydrates is depleted compared with gas sources, which confirms that the dissolution–migration of gases is a mechanism to enrich ethane near the BSR; (2) the proportion of C2H6 in structure I (sI) or structure II (sII) hydrates decreases with decreasing temperature, and decreasing temperature enlarges the difference of diffusion coefficient between methane and ethane and enhances the gas fractionation during migration, which could cause the increase upwardly C1/C2 ratios in the hydrate-occurring zone. A simplified geological model was proposed to explain the variability of hydrate composition with depth in the hydrate-occurring zone and the fractionation of gases near the BSR.

Rachel Hoffmann, Dilys Roe

Luo Jing, Pei Xiangjun, Li Junhao et al.

[Objective] The effects of breccias and round gravels on steep cut slope infiltration, runoff, sediment yield, and hydrodynamic characteristics were analyzed in order to provide a theoretical basis for a soil erosion prediction model and soil conservation on a steep cut slope on the Qinghai-Tibet Plateau. [Methods] Based on the shape and material composition of a steep cut slope and on climatic characteristics along the Pai-Mo road, the cut slope runoff and sediment yield process was observed by using indoor simulated rainfall experiments. The experimental conditions were 50° slope, 120 mm/h rainfall intensity, different gravel contents (30%, 40%, 50%), and different gravel roundness (pebble, breccia). [Results] The average infiltration rate for the pebble slope was higher than for the breccia slope. The average runoff rate for the pebble slope was lower than for the breccia slope. The initial runoff time for the pebble slope was significantly later than for the breccia slope. The water flow state and pattern for both slopes were laminar and jet, respectively. Although the runoff shear force and Reynolds number for the pebble slope was slightly smaller than for the breccia slope, the Froude number and the average flow velocity for the pebble slope were larger than for the breccia slope. Therefore, the ability of runoff to carry sediment was greater for the pebble slope. The sediment yield rate for the pebble slope was double the rate observed for the breccia slope, and the total sediment yield for the pebble slope was about 20% higher than for the breccia slope. [Conclusion] Because pebbles do not fit closely together in the soil, they are more likely to cause turbulence under heavy rainfall, causing small annular rills to form centered on the pebbles scattered all over the pebble slope. The rill density and total sediment yield will be greater for a steep cut slope underlain by alluvial deposits than for a steep cut slope underlain by colluvial deposits.

Alexandra Lewis, Miria Pelletier

Introduction

André Morrill, Ólafur K. Nielsen, Karl Skírnisson et al.

Aggregation of macroparasites among hosts is a near-universal pattern, and has important consequences for the stability of host-parasite associations and the impacts of disease. Identifying which potential drivers are contributing to levels of aggregation observed in parasite-host associations is challenging, particularly for observational studies. We apply beta regressions in a Bayesian framework to determine predictors of aggregation, quantified using Poulin’s index of discrepancy (D), for 13 species of parasites infecting Icelandic Rock Ptarmigan (Lagopus muta) collected over 12 years. 1,140 ptarmigan were collected using sampling protocols maximizing consistency of sample sizes and of composition of host ages and sexes represented across years from 2006–2017. Parasite species, taxonomic group (insect, mite, coccidian, or nematode), and whether the parasite was an ecto- or endoparasite were tested as predictors of aggregation, either alone or by modulating an effect of parasite mean abundance on D. Parasite species was an important predictor of aggregation in models. Despite variation in D across samples and years, relatively consistent aggregation was demonstrated for each specific host-parasite association, but not for broader taxonomic groups, after taking sample mean abundance into account. Furthermore, sample mean abundance was consistently and inversely related to aggregation among the nine ectoparasites, however no relationship between mean abundance and aggregation was observed among the four endoparasites. We discuss sources of variation in observed aggregation, sources both statistical and biological in nature, and show that aggregation is predictable, and distinguishable, among infecting species. We propose explanations for observed patterns and call for the review and re-analysis of parasite and other symbiont distributions using beta regression to identify important drivers of aggregation—both broad and association-specific.

Junqiang Shen, Junqiang Shen, Junqiang Shen et al.

We herein report the observation of a slope undercurrent beneath the winter western boundary current of the northwestern South China Sea (SCS), and its spatiotemporal variation. The possible underlying dynamics are also discussed. In situ observations reveal that the northeastward undercurrent is located above the upper slope with a core velocity exceeding 20 cm/s, which extends from 200 m to 800 m in depth with a width of 30–50 km and an along-slope length of approximately 200 km in deep winter of 2006-2007, and is characterized with interseasonal and interannual variabilities. The existence of this undercurrent is also supported by Hybrid Coordinate Ocean Model (HYCOM) results. We find that the slope undercurrent is probably driven by the along-slope pressure gradient associated with the sea level set-up off the continental slope of south Hainan Island and modulated by mesoscale eddies and Rossby waves. This study will renew our knowledge of the deep slope currents in the northwestern SCS.

Lin Fei, Chi Zelong, Yang Wei et al.

[Objective] The temporal and spatial variation characteristics of ecosystem service value in Fenhe River basin from 1980 to 2020 were analyzed to provide theoretical reference for scientific regulation and management of ecological environment in the basin. [Methods] Based on interpretation data of landsat-MSS/TM/ETM remote sensing image from 1980 to 2020, the land use change characteristics of Fenhe River basin were studied, and the ecosystem service value was estimated. [Results] From 1980 to 2020, the cropland, forest and grassland had been in the leading position in the land use of Fenhe River basin. The overall change of land use was mainly from cropland to construction land, and the changing rate of land use from 2000 to 2020 was significantly higher than that from 1980 to 2000. The annual value of total ecosystem services in the Fenhe River basin decreased from 1980 to 2020. The spatial distribution of ecosystem service value (ESV) was higher in the upstream and lower in the downstream. From the perspective of different function values, the regulation and support services decreased the most. The land use degree and ESVI bivariate LISA aggregation map showed a significantly spatially negative autocorrelation pattern, which was mainly dominated by low land use degree and high ESVI aggregation distribution in the upper reaches of Fenhe River. [Conclusion] Land use/cover change of Fenhe River basin had a great impact on ESV during 1980—2020. Measures such as improving the level of land intensive use should be used to improve land use structure developing towards high ESV.

Dhanya Vijay, Bincy Baby, Bincy Baby et al.

Vibrio gazogenes PB1 is an estuarine bacterium that was first isolated from saltwater mud. This bacterial species possesses the metabolic capacity to produce prodigiosin which has potential uses as an anticancer agent, antibiotic, and a fungicide. We evaluated the feasibility of employing V. gazogenes PB1 as a bacterial host for the production of prodigiosin. V. gazogenes PB1 could be grown and maintained using the well-known lysogeny broth medium when supplemented with NaCl, and revived after storage at -80°C. Under batch conditions, growth of V. gazogenes PB1 in minimal media and production of prodigiosin was observed over a wide range of NaCl concentrations from 1 to 5% (w/v). The production of prodigiosin was significantly influenced by the concentration of glucose (as the carbon source), ammonium chloride (as the nitrogen source), inorganic phosphate ions, as well as pH. The greatest titer (231 mg/L) was observed in minimal media that contained 1% (w/v) glucose, 100 mM ammonium chloride and 100 mM potassium phosphate buffer. The sequences and chromosomal locations of the pig genes associated with prodigiosin biosynthesis are revealed for the first time. PigA is an isolated gene on chromosome 2, while the remaining pig genes, from pigB to pigN, exist as a 20 kb gene cluster on chromosome 1. Given its excellent growth in a range of NaCl concentrations, wide availability from culture collections and low-risk status for experimental work, we would conclude that V. gazogenes PB1 is a promising bacterial host for the production of prodigiosin.

J. M. McPherson, Pamela A. Popielarz, S. Drobnič

Aprajita Singh, Sajjad Karimi, Aleksandar Vidakovic et al.

Changes in gut microbial composition over time in rainbow trout fed differentially processed diets supplemented with the filamentous fungi Neurospora intermedia were investigated in a 30-day feeding trial. Fish were fed a reference diet, non-preconditioned diet (NPD), or preconditioned (heat-treated) diet (PD), with the same inclusion level of N. intermedia in diets NPD and PD. Gut microbiota were analyzed on day 0, 10, 20, and 30. Gut microbial composition was similar for all diets on day 0, but was significantly different at day 10 and day 20. On day 30, the gut again contained similar communities irrespective of diet. The overall gut microbiota for each diet changed over time. Abundance of Peptostreptococcus and Streptococcus was higher in the initial days of feeding in fish fed on commercial diet, while a significant increase in lactic acid bacteria (Lactococcus lactis) was observed on day 30. Feed processing (preconditioning) did not contribute largely in shaping the gut microbiome. These results indicate that dietary manipulation and duration of feeding should be considered when evaluating gut microbial composition in cultured fish. A minimum 30-day feeding trial is suggested for gut microbiome, host and diet interaction studies.

Christopher Serenari

Abstract The number of species reliant on consistent human intervention is rising. These species are labeled conservation‐reliant, which affords them unique resources to propagate them. A conservation reliance designation has important implications for recovery of large carnivores, particularly where private lands encompass historical ranges. As a policy tool, a conservation reliance designation may be used in conjunction with other popular instruments such as financial incentives or co‐governance to promote coexistence between carnivores and key cohorts such as landowners and hunters, who are often vocal dissidents of carnivore recovery, especially wolf recovery projects. Yet, the nascent literature on conservation reliance has yet to address the influence of conservation reliance on landowner or hunter support for carnivore conservation. This paper fills this gap with an analysis of responses from 639 landowners to explore the influence of a conservation reliance designation on intention to coexist with wild red wolves (Canis rufus) in northeast North Carolina. Findings suggest that respondents living in the red wolf recovery zone generally oppose a conservation reliance designation, a critical means to red wolf recovery. Hence, a conservation reliance designation may actually erode the value of some species they intend to preserve. Disapproval of conservation reliance poses new confronts to restoration politics and its diversity of strands, which must be woven into new ways of thinking about the ethical and political aspects of carnivore policy and management.

Tanja K. Petersen, James D. M. Speed, Vidar Grøtan et al.

Abstract 1. The availability and quantity of observational species occurrence records have greatly increased due to technological advancements and the rise of online portals, such as the Global Biodiversity Information Facility (GBIF), coalescing occurrence records from multiple datasets. It is well‐established that such records are biased in time, space and taxonomy, but whether these datasets differ in relation to origin have not been assessed. If biases are specific to different types of datasets, and the relative contribution from these datasets have changed over time, these shifting biases will have implications for interpretations of results and, consequentially, for management and conservation measures. 2. We examined observational GBIF records from Norway to test potential differences in taxonomic, time and land‐cover biases between 10 different datasets, with a focus on red‐listed and non‐native species. 3. The datasets differ in their taxonomic coverage, with datasets dominated by citizen scientist recorders focusing greatly on birds. The number of records has increased over time; in particular, citizen science datasets have had a sharp increase in recent years. 4. The different datasets (including division of the datasets by conservation status) showed differences in geographical coverage. Anthropogenic land covers have more records than would be expected by chance in the majority of cases. Remote areas have fewer records than would be expected, underlining the prevalence of a roadside bias. 5. Accounting for biases in opportunistic species occurrence records need to be a dynamic rather than static process, as the taxonomic and geographical biases have changed over time and differ between datasets, depending on origin and inherent characteristics. Data‐collection programmes should be designed to counteract the biases of the specific datasets, and methods to account for the biases in existing data should be developed. When utilizing compiled, open‐source data, care must be taken to ensure complementarity between the datasets, both regarding time and space. Incorporating strengths and accounting for biases between datasets can strengthen the integration between species occurrence records with different origins for science‐policy impact and management.

Nathan Ewen

Following the end of the War of 1812, there was a conscious effort on the part of prominent Upper Canadians to immortalize the deeds and contributions of the Canadian Militia. Hugely overstating their meagre efforts,  these figures claimed the lions share of victory for the citizen soldiers, ignoring the far more meaningful and significant effect that British redcoats and Indigenous warriors had in defeating the Americans. By creating this myth these prominent men, many of whom served in the militia, sought to enrich and entrench their positions in Upper Canadian society. Additionally, this Militia Myth helped form a new sense of Canadian identity (a specifically British version of it), that would be crucial in fostering a new nationalism that would emerge in mid-19th century Upper Canada.

S. Martins, C. Martins, Larissa Maria et al.

The review articles on cell immobilization have been published since 1980 and reflect the general interest in this topic. Immobilized microbial cells create opportunities in a wide range of sectors including environmental pollution control. Compared with suspended microorganism technology, cell immobilization shows many advantages, such as resistance to toxic chemicals. This review presents the potential of immobilized microbial cells for treatment of toxic pollutants in industrial wastewater, the fundamentals, history and advantages of immobilized cells compared with suspended cells, characteristics of support materials and the principal methods of immobilization, with special emphasis for natural immobilization by cell adsorption. Keywords : Cell immobilization, microorganisms, adsorption, toxic pollutants, wastewater African Journal of Biotechnology Vol. 12(28), pp. 4412-4418

Nikos Solounias, Nikos Solounias, Melinda Danowitz et al.

The hypsodont crown of Equus and of other hypsodont ungulates has two functions: It has an extra crown in the alveolus which erupts and becomes a functional crown that enables the horse to live longer and feed on abrasive foods and grit. The second functional aspect is that the crown, while it is in the alveolus, acts as a root to support high stress during mastication. In general, roots do not increase in size during evolution when the tooth crown increases. Delayed development of the true root is a heterochrony phenomenon and is possibly dynamically interactive with the forces applied on the crown. Thus, when the crown becomes worn, as in old age, the mastication forces acting on it are very strong. This is an interesting phenomenon and reinforces our hypothesis of the second functional difference that the young tooth's crown embedded in the alveolus acts as a supporting root. The Equus hypsodont tooth has been represented by a class I lever. That is, the fulcrum is in the middle: the effort is applied on one side of the fulcrum and the resistance (or load) on the other side, for example, as in a crowbar. As an individual Equus ages, the alveolar tooth height decreases. Data display an exponential increase in force generated as tooth height decreases. The elongation and closure of the root is delayed until the crown is almost entirely worn. When the crown becomes worn, the mastication forces acting on it are very strong. This is an interesting phenomenon and reinforces our hypothesis that the young tooth's crown, embedded in the alveolus, acts as a supporting root. This discovery is based on the observation that fossil ungulates most commonly die at an early age, leaving a substantial amount of crown unused. The unused crown is not likely a reserve tooth crown for a season of hardship because it is rare to find examples of such hardships in the fossil record.