Segui questo link per vedere altri tipi di pubblicazioni sul tema: Frogs Research.
Articoli di riviste sul tema "Frogs Research"
Cita una fonte nei formati APA, MLA, Chicago, Harvard e in molti altri stili
Vedi i top-50 articoli di riviste per l'attività di ricerca sul tema "Frogs Research".
Accanto a ogni fonte nell'elenco di riferimenti c'è un pulsante "Aggiungi alla bibliografia". Premilo e genereremo automaticamente la citazione bibliografica dell'opera scelta nello stile citazionale di cui hai bisogno: APA, MLA, Harvard, Chicago, Vancouver ecc.
Puoi anche scaricare il testo completo della pubblicazione scientifica nel formato .pdf e leggere online l'abstract (il sommario) dell'opera se è presente nei metadati.
Vedi gli articoli di riviste di molte aree scientifiche e compila una bibliografia corretta.
1
Sugiura, Shinji. "Anti-predator defences of a bombardier beetle: is bombing essential for successful escape from frogs?" PeerJ 6 (30 novembre 2018): e5942. http://dx.doi.org/10.7717/peerj.5942.
Testo completoAbstract (sommario):
Some animals, such as the bombardier beetles (Coleoptera: Carabidae: Brachinini), have evolved chemical defences against predators. When attacked, bombardier beetles can discharge noxious chemicals at temperatures of approximately 100 °C from the tip of their abdomens, “bombing” their attackers. Although many studies to date have investigated how bombardier beetles discharge defensive chemicals against predators, relatively little research has examined how predators modify their attacks on bombardier beetles to avoid being bombed. In this study, I observed the black-spotted pond frog Pelophylax nigromaculatus (Anura: Ranidae) attacking the bombardier beetle Pheropsophus jessoensis under laboratory conditions. In Japan, Pe. nigromaculatus is a generalist predator in grasslands where the bombardier beetle frequently occurs. Almost all the frogs (92.9%) observed rejected live bombardier beetles; 67.9% stopped their attacks once their tongues touched the beetles, and 25.0% spat out the beetles immediately after taking the beetles into their mouths. No beetle bombed a frog before being taken into a frog’s mouth. All beetles taken into mouths bombed the frogs. Only 7.1% of the frogs swallowed live bombardier beetles after being bombed in the mouth. When dead beetles were provided instead, 85.7% of the frogs rejected the dead beetles, 71.4% stopped their attacks after their tongues touched the beetles, and 14.3% spat out the beetles. Only 14.3% of the frogs swallowed the dead beetles. The results suggest that the frogs tended to stop their predatory attack before receiving a bombing response from the beetles. Therefore, bombing was not essential for the beetles to successfully defend against the frogs. Using its tongue, Pe. nigromaculatus may be able to rapidly detect a deterrent chemical or physical characteristics of its potential prey Ph. jessoensis and thus avoid injury by stopping its predatory attack before the beetle bombs it.
2
Grainger, Roger. "Using ‘Frogs’ in Research". Dramatherapy 19, n. 3 (dicembre 1997): 3–5. http://dx.doi.org/10.1080/02630672.1997-1998.9689456.
Testo completo
3
Hazell, Donna. "Frog ecology in modified Australian landscapes: a review". Wildlife Research 30, n. 3 (2003): 193. http://dx.doi.org/10.1071/wr02075.
Testo completoAbstract (sommario):
Frog decline in Australia has often occurred where habitat is relatively intact. Habitat alteration and loss do, however, threaten many species. Widespread degradation of aquatic and terrestrial systems has occurred since European settlement, with only 6.4% of Australia's landmass reserved for conservation. But what do we know about how frogs use modified Australian landscapes? Do wildlife managers have the information required to ensure that frog habitat is considered in the management and revegetation of these areas? This review examines published Australian research on frogs to determine knowledge on processes of habitat loss and degradation. Literature that informs landscape restoration and revegetation is also examined to determine whether the habitat needs of frogs are considered. While many threats associated with frog habitat loss and change have been identified there is little quantitative information on frog–habitat relationships in modified landscapes, habitat fragmentation or knowledge of the connectivity required between terrestrial and aquatic frog habitat. Without this information frogs have largely been ignored in efforts to revegetate and manage for the conservation of Australian biota outside reserves. Ecological frog research in modified landscapes is required to avoid land-management decisions and conservation strategies based on inappropriate assumptions of how biota respond to landscape change.
4
Woinarski, J. C. Z., S. M. Legge, L. A. Woolley, R. Palmer, C. R. Dickman, J. Augusteyn, T. S. Doherty et al. "Predation by introduced cats Felis catus on Australian frogs: compilation of species records and estimation of numbers killed". Wildlife Research 47, n. 8 (2020): 580. http://dx.doi.org/10.1071/wr19182.
Testo completoAbstract (sommario):
Abstract ContextWe recently estimated the numbers of reptiles, birds and mammals killed by cats (Felis catus) in Australia, with these assessments providing further evidence that cats have significant impacts on Australian wildlife. No previous studies have estimated the numbers of frogs killed by cats in Australia and there is limited comparable information from elsewhere in the world. AimsWe sought to (1) estimate the numbers of frogs killed by cats in Australia and (2) compile a list of Australian frog species known to be killed by cats. MethodsFor feral cats, we estimated the number of frogs killed from information on their frequency of occurrence in 53 cat dietary studies (that examined stomach contents), the mean number of frogs in dietary samples that contained frogs, and the numbers of cats in Australia. We collated comparable information for take of frogs by pet cats, but the information base was far sparser. Key resultsFrogs were far more likely to be reported in studies that sampled cat stomachs than cat scats. The mean frequency of occurrence of frogs in cat stomachs was 1.5%. The estimated annual per capita consumption by feral cats in Australia’s natural environments is 44 frogs, and, hence, the annual total take is estimated at 92 million frogs. The estimated annual per capita consumption by pet cats is 0.26 frogs, for a total annual kill of one million frogs by pet cats. Thirty native frog species (13% of the Australian frog fauna) are known to be killed by cats: this tally does not include any of the 51 threatened frog species, but this may simply be because no cat dietary studies have occurred within the small ranges typical of threatened frog species. ConclusionsThe present study indicated that cats in Australia kill nearly 100 million frogs annually, but further research is required to understand the conservation significance of such predation rates. ImplicationsThe present study completed a set of reviews of the impacts of cats on Australian terrestrial vertebrates. Cat predation on Australian frogs is substantial, but is likely to be markedly less than that on Australian reptiles, birds and mammals.
5
LaDouceur, Elise E. B., Amanda M. Hauck, Michael M. Garner, Andrew N. Cartoceti e Brian G. Murphy. "Odontomas in Frogs". Veterinary Pathology 57, n. 1 (24 settembre 2019): 147–50. http://dx.doi.org/10.1177/0300985819877633.
Testo completoAbstract (sommario):
Odontomas are variably differentiated, hamartoma-like proliferations of odontogenic epithelium, pulp ectomesenchyme (odontoblasts), and dental matrix. Frogs are polyphyodont and homodont. Their teeth also differ from mammals in that they are restricted to the upper jaw in adults and lack a periodontal ligament and cementum, attaching directly to the underlying bone. Odontomas were identified in an African clawed frog ( Xenopus laevis), a false tomato frog ( Dyscophus guineti), and a tomato frog of unknown species ( Dyscophus sp.). All of the examined odontomas were composed of numerous tooth-like structures comprising an arc of dentinal matrix lined on the convex surface by ameloblasts and on the concave surface by odontoblasts. Masson’s trichrome and immunohistochemistry with pan-cytokeratin supported these findings. The pathogenesis of these lesions may be displacement of the dental lamina, which has been shown in research studies to lead to de novo proliferation of dental elements in frogs.
6
Koshevoy, N. D., V. V. Muratov, A. L. Kirichenko e S. A. Borisenko. "APPLICATION OF THE “JUMPING FROGS” ALGORITHM FOR RESEARCH AND OPTIMIZATION OF THE TECHNOLOGICAL PROCESS". Radio Electronics, Computer Science, Control 1, n. 1 (26 marzo 2021): 57–65. http://dx.doi.org/10.15588/1607-3274-2021-1-6.
Testo completoAbstract (sommario):
Context. An application of the method of a “jumping frogs” search algorithm to construct optimal experiment plans for cost (time) in the study of technological processes and systems that allow the implementation of an active experiment on them is proposed.
The object of study are optimization methods for cost (time) costs of experimental designs, based on the application of a “jumping frogs” search algorithm.
Objective. To obtain optimization results by optimizing the search of a “jumping frogs” search algorithm for the cost (time) costs of plans for a full factorial experiment.
Method. A method is proposed for constructing a cost-effective (time) implementation of an experiment planning matrix using algorithms for searching for “jumping frogs”. At the beginning, the number of factors and the cost of transitions for each factor level are entered. Then, taking into account the entered data, the initial experiment planning matrix is formed. Then, taking into account the entered data, the initial matrix of experiment planning is formed. The “jumping frogs” method determines the “successful frog” by the lowest cost of transitions between levels for each of the factors. After that, the permutations of the “frogs” are performed. The “frog” strives for the most “successful” and, provided it stays close, remains in the location. Then the gain is calculated in comparison with the initial cost (time) of the experiment.
Results. Software has been developed that implements the proposed method, which was used to conduct computational experiments to study the properties of these methods in the study of technological processes and systems that allow the implementation of an active experiment on them. The experimental designs that are optimal in terms of cost (time) are obtained, and the winnings in the optimization results are compared with the initial cost of the experiment. A comparative analysis of optimization methods for the cost (time) costs of plans for a full factorial experiment is carried out.
Conclusions. The conducted experiments confirmed the operability of the proposed method and the software that implements it, and also allows us to recommend it for practical use in constructing optimal experiment planning matrices.
7
Gardiner, David, A. Ndayibagira, Felix Grün e Bruce Blumberg. "Deformed frogs and environmental retinoids". Pure and Applied Chemistry 75, n. 11-12 (1 gennaio 2003): 2263–73. http://dx.doi.org/10.1351/pac200375112263.
Testo completoAbstract (sommario):
Since the early 1990s, a substantial number of deformed frogs have been observed in North America, particularly in the upper Midwest and Canada. Attempts to understand the etiology of the deformed frog problem have met with limited success to date with nearly as many proposed explanations as research groups working on the problem. Models for the mechanism underlying the development of deformed frogs include parasite/predation, ultraviolet radiation, and chemical exposure. Each model has its strengths and weaknesses. Despite contentious debate among researchers, there is an overall consensus that the increasing prevalence of deformed frogs is the result of a water-borne contaminant that has recently appeared, or reached a critical concentration. Our detailed analysis of malformed frogs collected in Minnesota ponds and lakes suggested that limb patterning was being modified by the disruption of a retinoid-sensitive developmental signaling pathway. Accordingly, we focused in the identification and characterization of bioactive retinoids from lake water and showed that retinoid treatment of frog embryos at sensitive times of development could recapitulate the full spectrum of limb abnormalities observed in field specimens in the laboratory. These data have led to the conclusion that inappropriate modulation of retinoid signaling by environmental contaminants is the mechanism underlying the increased incidence of frog malformations.
8
Tong, Qing, Xiao-peng Du, Zong-fu Hu, Li-yong Cui e Hong-bin Wang. "Modelling the growth of the brown frog (Rana dybowskii)". PeerJ 6 (16 maggio 2018): e4587. http://dx.doi.org/10.7717/peerj.4587.
Testo completoAbstract (sommario):
Well-controlled development leads to uniform body size and a better growth rate; therefore, the ability to determine the growth rate of frogs and their period of sexual maturity is essential for producing healthy, high-quality descendant frogs. To establish a working model that can best predict the growth performance of frogs, the present study examined the growth of one-year-old and two-year-old brown frogs (Rana dybowskii) from metamorphosis to hibernation (18 weeks) and out-hibernation to hibernation (20 weeks) under the same environmental conditions. Brown frog growth was studied and mathematically modelled using various nonlinear, linear, and polynomial functions. The model input values were statistically evaluated using parameters such as the Akaike’s information criterion. The body weight/size ratio (Kwl) and Fulton’s condition factor (K) were used to compare the weight and size of groups of frogs during the growth period. The results showed that the third- and fourth-order polynomial models provided the most consistent predictions of body weight for age 1 and age 2 brown frogs, respectively. Both the Gompertz and third-order polynomial models yielded similarly adequate results for the body size of age 1 brown frogs, while the Janoschek model produced a similarly adequate result for the body size of age 2 brown frogs. The Brody and Janoschek models yielded the highest and lowest estimates of asymptotic weight, respectively, for the body weights of all frogs. TheKwlvalue of all frogs increased from 0.40 to 3.18. TheKvalue of age 1 frogs decreased from 23.81 to 9.45 in the first four weeks. TheKvalue of age 2 frogs remained close to 10. Graphically, a sigmoidal trend was observed for body weight and body size with increasing age. The results of this study will be useful not only for amphibian research but also for frog farming management strategies and decisions.
9
Dökenel, Gülşah, e Selmin Özer. "Bacterial agents isolated from cultured marsh frog (Pelophylax ridibundus, Pallas 1771)". Ege Journal of Fisheries and Aquatic Sciences 36, n. 2 (15 giugno 2019): 115–24. http://dx.doi.org/10.12714/egejfas.2019.36.2.03.
Testo completoAbstract (sommario):
Marsh frogs (Pelophylax ridibundus) are preferred in European cuisine. In recent years, interest in farming of marsh frogs has increased, but little is known about their bacterial diseases. This research was carried out in a marsh frog farming operation in Mersin, Turkey, in order to determine the bacterial diversity. For this purpose, a total of 339 frog, 30 water, and 8 feed samples were collected. Isolation and identification of bacteria were carried out by conventional techniques and the VITEK-2 compact system. Antimicrobial susceptibility testing was performed by Kirby-Bauer disc diffusion method. A total of 239 isolates of 49 different species, including 31 Gram negative rod-shaped bacteria, 9 Gram positive rod-shaped sporeforming bacteria, and 9 Gram positive cocci-shaped non-sporeforming bacteria have been identified. These bacteria species were detected from 25 (83.3%) water, 5 (62.5%) feed samples, and 64 (84.2%) of 76 frog specimens. Antimicrobial susceptibility and MAR index values ranged between 1.4-95.8% and 0.13-0.73, respectively. In conclusion, the presence of opportunistic pathogenic bacteria in water, feed and frog specimens, which could pose risk for frogs and human health, have been detected in the marsh frog farm in Mersin. This study reveals, that further investigations are necessary for sustainable marsh frog breeding in Turkey.
10
Liu, Haorui, Fengyan Yi e Heli Yang. "Adaptive Grouping Cloud Model Shuffled Frog Leaping Algorithm for Solving Continuous Optimization Problems". Computational Intelligence and Neuroscience 2016 (2016): 1–8. http://dx.doi.org/10.1155/2016/5675349.
Testo completoAbstract (sommario):
The shuffled frog leaping algorithm (SFLA) easily falls into local optimum when it solves multioptimum function optimization problem, which impacts the accuracy and convergence speed. Therefore this paper presents grouped SFLA for solving continuous optimization problems combined with the excellent characteristics of cloud model transformation between qualitative and quantitative research. The algorithm divides the definition domain into several groups and gives each group a set of frogs. Frogs of each region search in their memeplex, and in the search process the algorithm uses the “elite strategy” to update the location information of existing elite frogs through cloud model algorithm. This method narrows the searching space and it can effectively improve the situation of a local optimum; thus convergence speed and accuracy can be significantly improved. The results of computer simulation confirm this conclusion.
11
GU^|^Eacute;NETTE, Sarah Annie, Marie-Chantal GIROUX e Pascal VACHON. "Pain Perception and Anaesthesia in Research Frogs". Experimental Animals 62, n. 2 (2013): 87–92. http://dx.doi.org/10.1538/expanim.62.87.
Testo completo
12
Mello, Sílvia Conceição Reis Pereira, Roberto Rodrigues de Oliveira, Marcelo Maia Pereira, Eliane Rodrigues, Willian Nascimento Silva e José Teixeira de Seixas Filho. "Development of a water recirculating system for bullfrog production: technological innovation for small farmers". Ciência e Agrotecnologia 40, n. 1 (febbraio 2016): 67–75. http://dx.doi.org/10.1590/s1413-70542016000100006.
Testo completoAbstract (sommario):
ABSTRACT Despite the technological progress in frog farming, issues related to the environment, biosafety, and the use of technologies that minimise environmental impacts are frequently neglected by farmers. With the goal of developing a low-cost technology for reuse and preservation of water quality, an anaerobic filtering system combined with an aerobic filtering system was implemented in the grow-out sector in the Frog Culture Research Unit at Fundação Instituto de Pesca do Estado do Rio de Janeiro (FIPERJ). The filtering system received the effluent from six pens of frogs that were populated with 362 frogs in different development phases. The efficiency of the filtering system was evaluated by an analysis of the water before and after passing through the filters. In addition to the standards of water quality, the animals' performance was also observed through monitoring rates of survival, weight gain and feed conversion ratio. The results showed the effectiveness of the filtering system by removing organic matter, on average 87%. The values of total ammonia and non-ionisable reached 1.04 and 0.004 mg/L, respectively. Also, frogs subjected to the system presented satisfactory rates of weight gain and a high survival rate (97%).
13
Backlin, Adam R., Cynthia J. Hitchcock, Elizabeth A. Gallegos, Julie L. Yee e Robert N. Fisher. "The precarious persistence of the Endangered Sierra Madre yellow-legged frog Rana muscosa in southern California, USA". Oryx 49, n. 1 (21 novembre 2013): 157–64. http://dx.doi.org/10.1017/s003060531300029x.
Testo completoAbstract (sommario):
AbstractWe conducted surveys for the Endangered Sierra Madre yellow-legged frog Rana muscosa throughout southern California to evaluate the current distribution and status of the species. Surveys were conducted during 2000–2009 at 150 unique streams and lakes within the San Gabriel, San Bernardino, San Jacinto, and Palomar mountains of southern California. Only nine small, geographically isolated populations were detected across the four mountain ranges, and all tested positive for the amphibian chytrid fungus Batrachochytrium dendrobatidis. Our data show that when R. muscosa is known to be present it is easily detectable (89%) in a single visit during the frog's active season. We estimate that only 166 adult frogs remained in the wild in 2009. Our research indicates that R. muscosa populations in southern California are threatened by natural and stochastic events and may become extirpated in the near future unless there is some intervention to save them.
14
Dare, O. K., e M. R. Forbes. "Patterns of trematode and nematode lungworm infections in northern leopard frogs and wood frogs from Ontario, Canada". Journal of Helminthology 83, n. 4 (26 marzo 2009): 339–43. http://dx.doi.org/10.1017/s0022149x09243495.
Testo completoAbstract (sommario):
AbstractIn this study we examined trematode and nematode lung helminths commonly found in two species of host ranid frogs for competitive interactions. We examined 147 adult (breeding and non-breeding) and juvenile northern leopard frogs, and 84 breeding male wood frogs in Bishops Mills, Ontario for Haematoloechus spp. (Trematoda) and Rhabdias sp. (Nematoda) infections. A strong negative association between phyla of helminth was observed in breeding and juvenile northern leopard frogs, and also in breeding wood frogs, but not in non-breeding adult northern leopard frogs. Few hosts carried both types of worm concurrently. Thirteen northern leopard frogs carried dual infections, while 77 carried only one phylum of helminth. Twenty-seven wood frogs carried dual infections, while 54 carried only one phylum of helminth. We also observed spatial segregation of the two phyla in host lungs. Our study informs future research on the dynamics of interactions among lung helminths in these two host species.
15
Mann, Reinier M., Ross V. Hyne, Paulina Selvakumaraswamy e Sergio S. Barbosa. "Longevity and larval development among southern bell frogs (Litoria raniformis) in the Coleambally Irrigation Area - implications for conservation of an endangered frog". Wildlife Research 37, n. 6 (2010): 447. http://dx.doi.org/10.1071/wr10061.
Testo completoAbstract (sommario):
Context. With the flow of many of the world’s rivers regulated such that water can be diverted for agriculture and human consumption, basic ecological information on the current status of key biota in significant floodplain wetlands and their response following inundation is needed. The maintenance of natural habitat to ensure amphibian survival is gaining increasing recognition, given the ongoing decline of anuran populations. Information on longevity, time required to emerge from the water and to reach sexual maturity, all provide important information about the required timing, frequency and duration of environmental water allocations to ensure successful recruitment among populations of southern bell frogs (Litoria raniformis Keferstein, 1867). Aims. The aims of this research were to establish the longevity of southern bell frogs in the Coleambally Irrigation Area (CIA) in the Riverina region of New South Wales, Australia, and to evaluate the capacity for southern bell frog tadpoles to survive and successfully metamorphose following an extended overwintering period. Methods. Skeletochronology studies were carried out using toe-clips taken from adult and juvenile frogs captured in irrigation channels and rice fields over two rice-growing seasons. For the metamorphosis assay, southern bell frog tadpoles were held back in their development by low temperatures and low food allocation for 290 days, before temperatures and food allocation were increased adequately to allow metamorphosis to occur. Key results. The study indicated that skeletochronological examination of toe-bones was a useful technique for establishing the age structure of southern bell frogs in this region. The oldest animals in the population were found to be 4–5 years old, although the majority of frogs were typically 2–3 years old. Also, the metamorphosis assay indicated that successful metamorphosis was the exception rather than the rule if tadpole development was held back by low food ration and low temperatures. Conclusions. If southern bell frogs reach sexual maturity only after 2 years, and the oldest animals observed in the field are 4 or 5 years old, then there is a very narrow window of opportunity – two to three seasons – for each individual to successfully breed. Implications. The implications for environmental flow management are that habitats for key species identified for protection such as the endangered southern bell frog will need water every 1–2 years to enable each cohort to breed and maintain the wild populations. The extent of the environmental flows needs to be adequate to ensure that water persists long enough for critical biological events such as anuran metamorphosis to occur during the spring and summer months.
16
Hirsch, Peter Buell. "The emasculation of frogs". Journal of Business Strategy 36, n. 3 (18 maggio 2015): 57–60. http://dx.doi.org/10.1108/jbs-03-2015-0024.
Testo completoAbstract (sommario):
Purpose – This article aims to suggest some ways in which the effectiveness of critical scientific communication might be improved. The persistence of anti-vaccine rhetoric, disputes about climate change and other scientific controversies have shone a light on the difficulty of communicating scientific information effectively to the public. Design/methodology/approach – The article looks at some recent research into neuroscience and human decision-making to suggest some best practices in communicating about science to the public. Findings – This literature review suggests that if we can embed rational arguments into a rich emotional narrative, we are more likely to overcome public skepticism and suspicion. Originality/value – While there has been much focus on human decision-making and cognitive bias, the relevant research has not often been related to the effectiveness of scientific communication.
17
Michaels, Christopher. "The effects of two calcium supplementation regimens on growth and health traits of juvenile mountain chicken frogs (Leptodactylus fallax)". Herpetological Journal, Volume 31 Number 1 (1 gennaio 2021): 18–26. http://dx.doi.org/10.33256/31.1.1826.
Testo completoAbstract (sommario):
The mountain chicken frog (Leptodactylus fallax) is among the 42 % of amphibians threatened with extinction and is dependent upon ex situ populations to recover in the wild. Amphibian captive husbandry is not fully understood and empirical data are required to optimise protocols for each species in captivity. Calcium metabolism and homeostasis are areas of importance in captive husbandry research and have been identified as a challenge in maintaining ex situ populations of L. fallax. We trialled two frequencies (twice and seven times weekly) of calcium supplementation via dusting of feeder insects in two groups of L. fallax juveniles and measured growth and health effects through morphometrics, radiography, ultrasonography and blood and faecal analysis over 167 days, followed by a further 230 days of monitoring on an intermediate diet informed by the initial dataset. We showed that supplementation treatment did not affect growth or health status as measured through blood analysis, radiography and ultrasonography. More frequent supplementation resulted in significantly more radiopaque endolymphatic sacs and broader skulls. Frogs fed more calcium excreted twice as much calcium in their faeces. The intermediate diet resulted in previously lower supplementation frogs approximating the higher supplementation frogs in morphometrics and calcium stores. Comparison with radiographic data from wild frogs showed that both treatments may still have had narrower skulls than wild animals, but mismatching age class may limit this comparison. Our data may be used to inform dietary supplementation of captive L. fallax as well as other amphibians.
18
Xu, Bo, Zhou Yu Fu e Zhao Yang Sun. "Research on the Relationship between Bionic Surface Friction Coefficient and Interface Medium". Advanced Materials Research 712-715 (giugno 2013): 387–90. http://dx.doi.org/10.4028/www.scientific.net/amr.712-715.387.
Testo completoAbstract (sommario):
The convex structure on tree frogs foot pats provide huge adsorption force, we can extract this facture of tree frogs foot pats, and apply on the surface of belt conveyor drum encapsulation in order to increase friction between drum and conveyor belt. But the environment underground is complex. There is always has coal particle and water on the frictional contact surface. The friction performance test was done by MMW-1A universal friction and wear tester in order to verify the friction coefficient of bionic surface under different conditions. At last, we figure out that water or coal particle has little influence on bionic friction surface, but has huge influence on common surface.
19
Huang, Xueliang, Hao Qiang, Qidong Zhang e Haijuan Li. "Research on ISFLA-Based Optimal Control Strategy for the Coordinated Charging of EV Battery Swap Station". Mathematical Problems in Engineering 2013 (2013): 1–7. http://dx.doi.org/10.1155/2013/613404.
Testo completoAbstract (sommario):
As an important component of the smart grid, electric vehicles (EVs) could be a good measure against energy shortages and environmental pollution. A main way of energy supply to EVs is to swap battery from the swap station. Based on the characteristics of EV battery swap station, the coordinated charging optimal control strategy is investigated to smooth the load fluctuation. Shuffled frog leaping algorithm (SFLA) is an optimization method inspired by the memetic evolution of a group of frogs when seeking food. An improved shuffled frog leaping algorithm (ISFLA) with the reflecting method to deal with the boundary constraint is proposed to obtain the solution of the optimal control strategy for coordinated charging. Based on the daily load of a certain area, the numerical simulations including the comparison of PSO and ISFLA are carried out and the results show that the presented ISFLA can effectively lower the peak-valley difference and smooth the load profile with the faster convergence rate and higher convergence precision.
20
Goldingay, R., G. Daly e F. Lemckert. "Assessing the Impacts of Logging on Reptiles and Frogs in the Montane Forests of Southern New South Wales." Wildlife Research 23, n. 4 (1996): 495. http://dx.doi.org/10.1071/wr9960495.
Testo completoAbstract (sommario):
This study describes an assessment of the medium-term effects of selection logging on the reptiles and frogs in the montane forests near Queanbeyan, New South Wales. A total of 15 reptile and two frog species was detected across 20 fixed-area plots that were selected according to broad forest type and logging history. Reptile species richness was not significantly different among the different habitat treatments. Total reptile abundance was significantly higher on logged plots, but was not influenced by forest moisture type. Individual analyses for five lizard species (accounting for 84% of all data) showed that several species (Eulamprus tympanum, E. heatwolei and Pseudemoia spenceri) had significantly greater abundances on the logged plots than on the unlogged plots, while two species (Nannoscincus maccoyi and Niveoscincus coventryi) did not differ significantly in their abundances across treatments. Thus, none of these species (which included arboreal, terrestrial and fossorial species) appeared to be adversely affected by past logging practices. Insufficient data on frogs were obtained for analysis. An additional 26 species (13 reptile and 13 frog species) were recorded during a regional survey involving 57 sites. Only two frog species were detected at more than 10 sites, illustrating the difficulty in obtaining data to determine whether logging has any impact on frog populations. Snakes are similarly difficult to assess: 13 snakes from six species were detected in this study. It is concluded that (i) the most abundant reptile species were not adversely affected by past logging, and (ii) many species of herpetofauna were patchy in their distribution across the study area, preventing resolution of the influence of habitat type or disturbance. The difficulty in collecting quantitative data on frogs and snakes confirms the importance of surveys that target endangered frog and snake species so that protective buffer zones can be delineated. Further research is required on these groups to assess the impact of forest management practices.
21
Skerratt, Lee F., Lee Berger, Nick Clemann, Dave A. Hunter, Gerry Marantelli, David A. Newell, Annie Philips et al. "Priorities for management of chytridiomycosis in Australia: saving frogs from extinction". Wildlife Research 43, n. 2 (2016): 105. http://dx.doi.org/10.1071/wr15071.
Testo completoAbstract (sommario):
To protect Australian amphibian biodiversity, we have identified and prioritised frog species at an imminent risk of extinction from chytridiomycosis, and devised national management and research priorities for disease mitigation. Six Australian frogs have not been observed in the wild since the initial emergence of chytridiomycosis and may be extinct. Seven extant frog species were assessed as needing urgent conservation interventions because of (1) their small populations and/or ongoing declines throughout their ranges (southern corroboree frog (Pseudophryne corroboree, New South Wales), northern corroboree frog (Pseudophryne pengilleyi, Australian Capital Territory, New South Wales), Baw Baw frog (Philoria frosti, Victoria), Litoria spenceri (spotted tree frog, Victoria, New South Wales), Kroombit tinkerfrog (Taudactylus pleione, Queensland), armoured mist frog (Litoria lorica, Queensland)) or (2) predicted severe decline associated with the spread of chytridiomycosis in the case of Tasmanian tree frog (Litoria burrowsae, Tasmania). For these species, the risk of extinction is high, but can be mitigated. They require increased survey effort to define their distributional limits and to monitor and detect further population changes, as well as well-resourced management strategies that include captive assurance populations. A further 22 frog species were considered at a moderate to lower risk of extinction from chytridiomycosis. Management actions that identify and create or maintain habitat refugia from chytridiomycosis and target other threatening processes such as habitat loss and degradation may be effective in promoting their recovery. Our assessments for some of these species remain uncertain and further taxonomical clarification is needed to determine their conservation importance. Management actions are currently being developed and trialled to mitigate the threat posed by chytridiomycosis. However, proven solutions to facilitate population recovery in the wild are lacking; hence, we prioritise research topics to achieve this aim. Importantly, the effectiveness of novel management solutions will likely differ among species due to variation in disease ecology, highlighting the need for species-specific research. We call for an independent management and research fund of AU$15 million over 5 years to be allocated to recovery actions as determined by a National Chytridiomycosis Working Group of amphibian managers and scientists. Procrastination on this issue will likely result in additional extinction of Australia’s amphibians in the near future.
22
Seburn, David C., Kari Gunson e Frederick W. Schueler. "Apparent widespread decline of the Boreal Chorus Frog (Pseudacris maculata) in eastern Ottawa". Canadian Field-Naturalist 128, n. 2 (6 luglio 2014): 151. http://dx.doi.org/10.22621/cfn.v128i2.1579.
Testo completoAbstract (sommario):
The Boreal Chorus Frog (Pseudacris maculata) was once common in the eastern Ottawa area. To assess its current status, we conducted auditory surveys at 184 wetlands in 2011 and 2012. Boreal Chorus Frogs were heard at only five (2.7%) of the surveyed sites. These five sites were spatially aggregated, with only 0.5–7.5 km between any two sites. Sites occupied by Boreal Chorus Frogs in eastern Ottawa were surrounded by significantly greater agricultural cover (at 1.0-, 1.5-, and 2.0-km radii), less forest cover (1.0- and 2.0-km radii), and less wetland cover (1.5- and 2.0-km radii) than occupied sites in western Ottawa. Sites in eastern Ottawa that were apparently unoccupied were surrounded by significantly greater agricultural cover (only at the 2.0-km radius), similar forest cover (all radii), and less wetland cover (all radii) compared with occupied sites in western Ottawa. Boreal Chorus Frog populations are commonly subject to extirpation resulting from stochastic events. The reduced wetland cover in eastern Ottawa may be accompanied by reduced wetland connectivity, making recolonization of wetlands difficult or impossible. Our data do not show whether wetland connectivity has been reduced, but future research should address this important topic.
23
Dalbeck, Lutz, Joyce Janssen e Sophie Luise Völsgen. "Beavers (Castor fiber) increase habitat availability, heterogeneity and connectivity for common frogs (Rana temporaria)". Amphibia-Reptilia 35, n. 3 (2014): 321–29. http://dx.doi.org/10.1163/15685381-00002956.
Testo completoAbstract (sommario):
Beavers (Castor fiber), as typical ecosystem engineers, alter living conditions especially for amphibians through the building of dams and felling of trees, thereby changing the hydroperiod and substantially affecting forest succession stages. In this study we quantify the effects of beavers on the availability of amphibian breeding waters in the Hürtgenwald, a woodland area in the Central European Rhenish Massif, its colonisation by common frogs (Rana temporaria) and the effects of age and succession stage of beaver ponds on ovipositional site selection. In 2013, beaver ponds comprised about half (49%) of all lentic water bodies but contained 82.5% of all common frog egg masses. Mature beaver ponds (>6 years old) harboured approximately half of the egg masses (), but new beaver ponds (1-3 years old) can also be home to large breeding aggregations. Abandoned beaver ponds are of minor importance as ovipositional sites for common frogs. High egg mass counts were also found in artificially-dammed ponds (). We believe that common frogs prefer occupied beaver ponds as ovipositional sites because of high insolation and a permanent hydroperiod, which lead to rapid tadpole emergence. Beaver ponds are generally located in close proximity to each other, facilitating movement and rapid colonisation by common frogs. Our research provides additional evidence to show that beavers enhance habitat availability, heterogeneity and connectivity, thereby fostering amphibian populations at a landscape level. As natural elements of small streams, beaver ponds must be taken into account in the context of the EU Water Framework Directive.
24
Wansbrough, Henry. "Two choruses of frogs?" Journal of Hellenic Studies 113 (novembre 1993): 162. http://dx.doi.org/10.2307/632407.
Testo completoAbstract (sommario):
In September 1991 I came across two parties of frogs in the bulrushes on either side of a still little pool at the Ain Qilt, some ten miles east of Jerusalem. The two parties were calling to each other in turn, as though singing antiphonally. The remarkable fact which struck me was that each group had a different chant, the one distinctly chanting only βρεκεκεκέξ, while the other replied equally distinctly with a consistent κοάξ, κοάξ. I observed this phenomenon for some ten minutes, but was not able to ascertain other differences between the two groups, such as sex, age, or temperament; but I thought that this fact, whatever its explanation, might be a significant contribution to field-research on Aristophanes.
25
Yudha, Donan Satria, Rury Eprilurahman, Hastin Ambar Asti, Herofi Azhar, Nurrochmah Wisudhaningrum, Puji Lestari, Siti Markhamah e Imam Sujadi. "Keanekaragaman katak dan kodok (Amphibia: Anura) di Suaka Margasatwa Paliyan, Gunungkidul, Yogyakarta". Jurnal Biologi Udayana 23, n. 2 (30 dicembre 2019): 59. http://dx.doi.org/10.24843/jbiounud.2019.v23.i02.p03.
Testo completoAbstract (sommario):
Frogs and toads commonly found by human. Frogs and toads could become a bio-indicator of anenvironment. Paliyan Wildlife Sanctuary is a forest area which posses several animal to protect and it’slocated in Gunungkidul Regency, Province of DIY. The diversity of frogs and toads in this wildlifesanctuary is not yet recorded and published. The aim of this research is to understand the diversity of frogsand toads in the area of Paliyan Wildlife Sanctuary. The results there were 9 species of frogs and toads, i.e.,Duttaphrynus melanostictus, Ingerophrynus biporcatus, Fejervarya limnocharis, Kaloula baleata,Occidozyga lima, Occidozyga sumatrana, Microhyla orientalis, Microhyla palmipes and Polypedatesleucomystax. The diversity of frogs and toads in the wildlife sanctuary is moderate according to theShannon-Wiener Index with value: 1,43. Area of Paliyan Wildlife Sanctuary is a suitable habitat for frogsand toads due to its location with dense forest, bushes, rivers, lakes and pools as well as least humanactivities.
26
Bruni, Giacomo. "Will there be a second extinction? Molecular identification of multiple alien water frogs (Pelophylax ridibundus sensu lato) in Tuscany, Central Italy, reveals genetic pollution within a unique hybridogenetic system". Herpetological Journal, Volume 30, Number 3 (1 luglio 2020): 147–58. http://dx.doi.org/10.33256/hj30.3.147158.
Testo completoAbstract (sommario):
The introduction of alien water frogs is perhaps one of the most underestimated herpetological conservation issues in Europe. The identification of distinct species is highly challenging at the phenotypic level, and artificial syntopy between various taxa and lineages may lead to diverse outcomes, including hybridisation and local extinction. In central Italy the native synklepton of Pelophylax bergeri (the parental taxon) and P. kl. (klepton) hispanicus (the hybridogenetic hybrid, which clonally transmits the genome of an extinct ridibundus-like taxon) is present. Until recently, data regarding the presence of alien water frogs in central Italy was scarce, and no alien taxa have been reported for Tuscany. In this study, four distinct non-native Pelophylax lineages have been identified via molecular analysis in the Cecina and Arno river basins and ascribed to the Marsh frog group (P. ridibundus sensu lato). Alien Pelophylax ridibundus, P. kurtmuelleri, and P. cf. bedriagae sensu stricto currently appear to be widespread in the Cecina basin. Furthermore, evidence of hybridisation with autochthonous taxa has been suggested by genetic analyses in four out of eight sampling localities. With a view to evaluate urgent conservation strategies, a greater sampling effort is required to assess the actual distribution and ecology of the alien lineages, and further research is necessary to measure their impact on the native hybridogenetic system of the central-southern Italian pool frogs.
27
Quick, Gemma, Ross L. Goldingay, Jonathan Parkyn e David A. Newell. "Population stability in the endangered Fleay’s barred frog (Mixophyes fleayi) and a program for long-term monitoring". Australian Journal of Zoology 63, n. 3 (2015): 214. http://dx.doi.org/10.1071/zo14106.
Testo completoAbstract (sommario):
In the wake of the global decline in amphibians there is a need for long-term population monitoring. Previous research suggested that the endangered Fleay’s barred frog (Mixophyes fleayi) had recovered after a severe decline. We aimed to determine whether this recovery has been sustained and to test an example of a monitoring program that could be employed at intervals of five or more years to assess long-term population stability. We conducted capture–mark–recapture five years after the last detailed census at Brindle Creek in Border Ranges National Park, New South Wales. Frogs were captured along a 200 m creek transect between September 2013 and February 2014. We used program Mark to estimate demographic parameters of adult male frogs using two modelling approaches: robust design (RD) and the POPAN formulation of the Jolly–Seber model. Abundance was estimated at 38.2 ± 0.5 (s.e.) (RD) and 46.0 ± 2.7 (POPAN). Abundance in 2008 was estimated at 53.2 ± 10.0 (POPAN) male frogs. Estimates of apparent monthly survival over our five-month-long study were very high (RD: 1.0 ± 0.0; POPAN: 1.0 ± 0.02). Recapture estimates were also high (RD: 0.40 ± 0.07 to 0.72 ± 0.05 per session; POPAN: 0.84 ± 0.05 per month). These data suggest that the Brindle Creek population has remained relatively stable over a period of ~10 years.
28
Plötner, Jörg, e Dirk Scmeller. "Some remarks on current research on western Palearctic water frogs". Zoosystematics and Evolution 77, n. 1 (22 aprile 2008): 3–4. http://dx.doi.org/10.1002/mmnz.20010770102.
Testo completo
29
Plötner, Jörg, e Dirk Scmeller. "Some remarks on current research on western Palearctic water frogs". Mitteilungen aus dem Museum für Naturkunde in Berlin. Zoologische Reihe 77, n. 1 (2001): 3–4. http://dx.doi.org/10.1002/mmnz.4850770102.
Testo completo
30
Brooks, Olivia L., e Ralph A. Saporito. "For poison frogs, bitter is better". Biochemist 41, n. 6 (2 dicembre 2019): 16–20. http://dx.doi.org/10.1042/bio04106016.
Testo completoAbstract (sommario):
You are what you eat. Although this common phrase is one that all animals can relate to, for poison frogs, what they choose to eat could be a matter of life and death. Poison frogs are famously known for the brilliant colours and striking patterns that bring attention to themselves (Figure 1)—but attention seekers they are not. Instead, they are engaged in a complex advertisement scheme, aimed to warn predators that they might want to eat something else. You see, poison frogs are chock-full of bitter-tasting alkaloids, which most predators find distasteful and many pathogens find hard to live with. Interestingly, these defensive chemicals don't just come from anywhere—instead, poison frogs choose to eat food items that are loaded with them, and then, like kleptomaniacs, they steal them for themselves! Where they get their alkaloids and how they use them in defence, all without poisoning themselves, is a fascinating story that is beginning to unfold from decades of research on the chemistry, ecology and molecular biology of these charismatic tropical frogs.
31
MONTAGUE, PETER. "Research Ethics and the Precautionary Principle: Marching toward Environmental Decay". Cambridge Quarterly of Healthcare Ethics 12, n. 4 (7 agosto 2003): 466–67. http://dx.doi.org/10.1017/s0963180103124176.
Testo completoAbstract (sommario):
I recently read through the most recent 24 issues of Environmental Health Perspectives—the National Institutes of Health journal of, among other issues, scientific research into how environmental contaminants impact animal and human health. It is a catalog of horrors from a public health perspective. Fish and frogs with their sex scrambled; deformed frogs with altered hormone levels in their blood; a nearly threefold increase in birth defects among Minnesota farm children exposed to pesticides; 2,4-D exposure reducing hormone levels in men; insignificant levels of four environmental chemicals adding up to a significant dose; a third study reconfirming a 50% sperm decline in U.S. men, 1934–1996; phthalates elevated in the blood of Puerto Rican girls developing breasts before they are 8; some 6,000 chemicals declared candidates for study as hormone disrupters (selected by computer from a universe of 58,000 chemicals for “most” of which we have “no biologic data”); children living near incinerators having delayed sexual development; hypospadias linked to organochlorine levels in the blood of mink, otter, and polar bears; and “No living organism may be considered DDT-free.” Nothing definitive, but it all suggests that things are tending in a direction that is perfectly awful.
32
Rojas, Bibiana, e Andrius Pašukonis. "From habitat use to social behavior: natural history of a voiceless poison frog, Dendrobates tinctorius". PeerJ 7 (17 settembre 2019): e7648. http://dx.doi.org/10.7717/peerj.7648.
Testo completoAbstract (sommario):
Descriptive studies of natural history have always been a source of knowledge on which experimental work and scientific progress rely. Poison frogs are a well-studied group of small Neotropical frogs with diverse parental behaviors, distinct calls, and bright colors that warn predators about their toxicity; and a showcase of advances in fundamental biology through natural history observations. The dyeing poison frog, Dendrobates tinctorius, is emblematic of the Guianas region, widespread in the pet trade, and increasingly popular in research. This species shows several unusual behaviors, such as the lack of advertisement calls and the aggregation around tree-fall gaps, which remain poorly described and understood. Here, we summarize our observations from a natural population of D. tinctorius in French Guiana collected over various field trips between 2009 and 2017; our aim is to provide groundwork for future fundamental and applied research spanning parental care, animal dispersal, disease spread, habitat use in relation to color patterns, and intra-specific communication, to name a few. We report sex differences in habitat use and the striking invasion of tree-fall gaps; describe their courtship and aggressive behaviors; document egg development and tadpole transport; and discuss how the knowledge generated by this study could set the grounds for further research on the behavior, ecology, and conservation of this species.
33
Bina Perl, R. G., Sarig Gafny, Yoram Malka, Sharon Renan, Douglas C. Woodhams, Louise Rollins-Smith, James D. Pask, Molly C. Bletz, Eli Geffen e Miguel Vences. "Natural history and conservation of the rediscovered Hula painted frog, Latonia nigriventer". Contributions to Zoology 86, n. 1 (13 febbraio 2017): 11–37. http://dx.doi.org/10.1163/18759866-08601002.
Testo completoAbstract (sommario):
Dramatic global amphibian declines have recently led to an increased concern for many species of this animal class. The enigmatic Hula painted frog (Latonia nigriventer), the first amphibian to be declared extinct but unexpectedly rediscovered in 2011, has remained one of the rarest and most poorly understood amphibians worldwide. Gathering basic biological information on this species, along with an understanding of its disease-related threats remains fundamental for developing risk assessments and conservation strategies. Our surveys in recent years confirmed that L. nigriventer is a localised species with elusive habits. The species appears to follow an opportunistic breeding phenology and has a tadpole morphology similar to its well-studied sister group Discoglossus. However, the adults’ extended annual presence in the aquatic habitat is a major difference from species of Discoglossus. We detected the amphibian chytrid fungus, Batrachochytrium dendrobatidis (Bd), in northern Israel and on Hula painted frogs but did not observe any signs of chytridiomycosis in this species. Our preliminary data on aspects of the innate immunity of L. nigriventer suggest that the skin mucosome of this species contains antimicrobial peptides and a bacterial community differing from other syntopic frogs (Pelophylax bedriagae). The combined knowledge of both natural history and innate immunity of L. nigriventer provides valuable insights to direct future research and conservation management of this critically endangered frog species.
34
Lewis, Carrie H. R., Corinne L. Richards-Zawacki, Roberto Ibáñez, Jennifer Luedtke, Jamie Voyles, Paul Houser e Brian Gratwicke. "Conserving Panamanian harlequin frogs by integrating captive-breeding and research programs". Biological Conservation 236 (agosto 2019): 180–87. http://dx.doi.org/10.1016/j.biocon.2019.05.029.
Testo completo
35
Huang, Min Yi, Ren Yan Duan e Xiao Li Ji. "Amphibian as a Model to Study Environmental Problem". Applied Mechanics and Materials 71-78 (luglio 2011): 3179–82. http://dx.doi.org/10.4028/www.scientific.net/amm.71-78.3179.
Testo completoAbstract (sommario):
In order to obtain a better insight of the possible threat of environmental factor to wildlife, especially to amphibians, we studied influences of dicofol on heart rate inR. nigromaculataby applying biological signal recording and monitoring system.R. nigromaculatawas injected in ventral lymph follicle in different doses of dicofol solution, and then observed the changes of heart rate after 7 days. The results showed that with the concentration of dicofol solution increasing, the heart rate, systolic tension and diastolic tension changed. The aim of this research is to discuss the cause of dicofol on the physiology in frogs. It can be concluded that dicofol affects the electronic activity of the frog’s heart.
36
Animalesto, Gloria. "The infection of trematodes on rice frogs (Fejervarya cancrivora) in Karawang Regency, West Java". BIO Web of Conferences 19 (2020): 00004. http://dx.doi.org/10.1051/bioconf/20201900004.
Testo completoAbstract (sommario):
Fejervarya cancrivora is often used as raw material for food and export commodities. In 2014, it was recorded that Karawang Regency was the largest producer of frog’s legs meat in West Java. Research on trematode worms of F. cancrivora from Karawang Regency was conducted to find out the diversity of trematodes worms and its infection patterns. The observation was carried out on 120 frogs. The lungs, stomach, intestine, and caecum were examined for trematodes. The results showed that the F. cancrivora infected by four species of trematodes i.e., Glypthelmins sp., Pleurogenoides sp., Haematoloechus sp., and Diplodiscus sp. with a prevalence of 25.8%, 18.3%, 35.8%, and 23.3%, respectively, and parasite index 1 -25, 1-268, 1-19, and 1-23 individual parasite in each host, respectively.
37
Garg, Sonali, Robin Suyesh, Sandeep Das, Mark A. Bee e S. D. Biju. "An integrative approach to infer systematic relationships and define species groups in the shrub frog genus Raorchestes, with description of five new species from the Western Ghats, India". PeerJ 9 (3 marzo 2021): e10791. http://dx.doi.org/10.7717/peerj.10791.
Testo completoAbstract (sommario):
The genus Raorchestes is a large radiation of Old World tree frogs for which the Western Ghats in Peninsular India is the major center for origin and diversification. Extensive studies on this group during the past two decades have resolved long-standing taxonomic confusions and uncovered several new species, resulting in a four-fold increase in the number of known Raorchestes frogs from this region. Our ongoing research has revealed another five new species in the genus, formally described as Raorchestes drutaahu sp. nov., Raorchestes kakkayamensis sp. nov., Raorchestes keirasabinae sp. nov., Raorchestes sanjappai sp. nov., and Raorchestes vellikkannan sp. nov., all from the State of Kerala in southern Western Ghats. Based on new collections, we also provide insights on the taxonomic identity of three previously known taxa. Furthermore, since attempts for an up-to-date comprehensive study of this taxonomically challenging genus using multiple integrative taxonomic approaches have been lacking, here we review the systematic affinities of all known Raorchestes species and define 16 species groups based on evidence from multi-gene (2,327 bp) phylogenetic analyses, several morphological characters (including eye colouration and pattern), and acoustic parameters (temporal and spectral properties, as well as calling height). The results of our study present novel insights to facilitate a better working taxonomy for this rather speciose and morphologically conserved radiation of shrub frogs. This will further enable proper field identification, provide momentum for multi-disciplinary studies, as well as assist conservation of one of the most colourful and acoustically diverse frog groups of the Western Ghats biodiversity hotspot.
38
Davenport, J. M., P. A. Seiwert, L. A. Fishback e W. B. Cash. "The effects of two fish predators on Wood Frog (Lithobates sylvaticus) tadpoles in a subarctic wetland: Hudson Bay Lowlands, Canada". Canadian Journal of Zoology 91, n. 12 (dicembre 2013): 866–71. http://dx.doi.org/10.1139/cjz-2013-0091.
Testo completoAbstract (sommario):
Fish can have strong predatory impacts on aquatic food webs. Indeed, fish are known to have strong effects on amphibians, with some species being excluded from communities where fish are present. Most research with amphibians and fish has focused on lower latitudes and very little is known of amphibian–fish interactions at higher latitudes. Therefore, we conducted an enclosure experiment in a subarctic natural wetland to examine the predatory effects of two species of fish, brook sticklebacks (Culaea inconstans (Cuvier, 1829)) and ninespine sticklebacks (Pungitius pungitius (L., 1758)), on the survival and growth of Wood Frogs (Lithobates sylvaticus (LeConte, 1825)). We found no significant difference in survival and size at metamorphosis among the two fish species treatments and fish-free treatments. We found that individuals from fish-free treatments metamorphosed earlier than those from either fish species present treatment. Our work suggests that stickleback fish predation may not have a major impact on Wood Frog tadpole survival and growth in a subarctic wetland. Sticklebacks may still have an impact on earlier developmental stages of Wood Frogs. This work begins to fill an important gap in potential factors that may impact larval amphibian survival and growth at higher latitudes.
39
Chao, Kuo-Wei, Nian-Ze Hu, Yi-Chu Chao, Chin-Kai Su e Wei-Hang Chiu. "Implementation of Artificial Intelligence for Classification of Frogs in Bioacoustics". Symmetry 11, n. 12 (26 novembre 2019): 1454. http://dx.doi.org/10.3390/sym11121454.
Testo completoAbstract (sommario):
This research presents the implementation of artificial intelligence (AI) for classification of frogs in symmetry of the bioacoustics spectral by using the feedforward neural network approach (FNNA) and support vector machine (SVM). Recently, the symmetry concept has been applied in physics, and in mathematics to help make mathematical models tractable to achieve the best learning performance. Owing to the symmetry of the bioacoustics spectral, feature extraction can be achieved by integrating the techniques of Mel-scale frequency cepstral coefficient (MFCC) and mentioned machine learning algorithms, such as SVM, neural network, and so on. At the beginning, the raw data information for our experiment is taken from a website which collects many kinds of frog sounds. This in fact saves us collecting the raw data by using a digital signal processing technique. The generally proposed system detects bioacoustic features by using the microphone sensor to record the sounds of different frogs. The data acquisition system uses an embedded controller and a dynamic signal module for making high-accuracy measurements. With regard to bioacoustic features, they are filtered through the MFCC algorithm. As the filtering process is finished, all values from ceptrum signals are collected to form the datasets. For classification and identification of frogs, we adopt the multi-layer FNNA algorithm in machine learning and the results are compared with those obtained by the SVM method at the same time. Additionally, two optimizer functions in neural network include: scaled conjugate gradient (SCG) and gradient descent adaptive learning rate (GDA). Both optimization methods are used to evaluate the classification results from the feature datasets in model training. Also, calculation results from the general central processing unit (CPU) and Nvidia graphics processing unit (GPU) processors are evaluated and discussed. The effectiveness of the experimental system on the filtered feature datasets is classified by using the FNNA and the SVM scheme. The expected experimental results of the identification with respect to different symmetry bioacoustic features of fifteen frogs are obtained and finally distinguished.
40
YEN, GARY G., e QIANG FU. "AUTOMATIC FROG CALLS MONITORING SYSTEM: A MACHINE LEARNING APPROACH". International Journal of Computational Intelligence and Applications 01, n. 02 (giugno 2001): 165–86. http://dx.doi.org/10.1142/s1469026801000184.
Testo completoAbstract (sommario):
Automatic recognition of frog vocalization is considered a valuable tool for a variety of biological research and environmental monitoring applications. In this research an automatic monitoring system, which can recognize the vocalizations of four species of frogs and can identify different individuals within the species of interest, is proposed. For the desired monitoring system, species identification is performed first with the proposed filtering and grouping algorithm. Individual identification, which can estimate frog population within the specific species, is performed in the second stage. Digital signal pre-processing, feature extraction, dimensionality reduction, and neural network pattern classification are performed step by step in this stage. Wavelet Packet feature extraction together with two different dimension reduction algorithms are synergistically integrated to produce final feature vectors, which are to be fed into a neural network classifier. The simulation results show the promising future of deploying an array of continuous, on-line environmental monitoring systems based upon nonintrusive analysis of animal calls.
41
Womble, Mandy A., Gregory A. Lewbart e Heather R. Shive. "Pathologic Lesions of the Budgett Frog (Lepidobatrachus laevis), an Emerging Laboratory Animal Model". Comparative Medicine 70, n. 3 (1 giugno 2020): 239–47. http://dx.doi.org/10.30802/aalas-cm-19-000071.
Testo completoAbstract (sommario):
Lepidobatrachus laevis, commonly called the Budgett frog, is a member of the horned frog family (Ceratophryidae), which has become increasingly popular among amphibian hobbyists. L. laevis is also used in biologic research on embryonic development, providing a novel model species for the study of organogenesis, regeneration, evolution, and biologic scaling. However, little scientific literature details disease processes or histologic lesions in this species. Our objective was to describe spontaneous pathologic lesions in L. laevis to identify disease phenotypes. We performed a retrospective analysis of 14 captive L. laevis frogs (wild-caught and captive-bred), necropsied at the NC State University College of Veterinary Medicine between 2008 and 2018. The majority of frogs exhibited renal changes, including varying combinations of tubular epithelial binucleation, karyomegaly, and cytoplasmic vacuolation; polycystic kidney disease; and renal carcinoma. Many of the renal changes are reminiscent of a condition described in Japanese (Bufo japonicus) and Chinese (Bufo raddei) toad hybrids that progresses from tubular epithelial atypia and tubular dilation to polycystic kidney disease to renal carcinoma. A second common finding was variably sized, randomly distributed bile duct clusters (biliary proliferation). Other noteworthy findings included regional or generalized edema, intestinal adenocarcinoma, aspiration pneumonia, and parasitism. This retrospective analysis is the first description of histologic lesions identified in captive L. laevis populations, providing new insight into spontaneous disease processes occurring in this species for use in disease diagnosis and clinical management.
42
Palamarenko, O. V. "ЗМЕНШЕННЯ ЧИСЕЛЬНОСТІ ТРАВ’ЯНОЇ ЖАБИ (RANA TEMPORARIA) ЯК ПОКАЗНИК НЕСТАБІЛЬНОСТІ ЛОКАЛЬНОЇ ЕКОСИСТЕМИ". Scientific Issue Ternopil Volodymyr Hnatiuk National Pedagogical University. Series: Biology 79, n. 1-2 (6 giugno 2020): 36–41. http://dx.doi.org/10.25128/2078-2357.20.1-2.4.
Testo completoAbstract (sommario):
In the 21st century, the existence of many species of amphibians on our planet has become quite problematic due to a number of adverse environmental factors of both natural and anthropogenic origin. Amphibian fauna in Ukraine is not an exception. By conducting a series of field studies and observations, the author has established changes that occurred in the population of the grass frog (Rana temporaria) in the territory of the Lypnyky Forestry of the State Enterprise "Lvivlis". From 2005 to 2019 a number of field studies were conducted and the fact of a sharp decrease in the number of this species was established. During 2005-2009, the number of frogs reached 16 individuals per 1,000 m route. In the last few years, the number is 0.1 individuals per 1000 m of route. The drying up of reservoirs in which amphibians lay eggs spawned a reason for the low success of young frogs after the metamorphosis. First of all, we are talking about large, previously stable reservoirs and, to a lesser extent, ephemeral forest puddles. Over the last 5-7 years, the number of inhabitants has increased significantly in the study area. We are talking about the villages of Solonka, Lypnyky, Kovyri and others located near the forest. Thus, due to the rise of population, the volume of sewage drains also increased. This is a major cause of pollution and degradation of wintering frogs. Due to the low level of oxygen in local ponds, it has become virtually impossible for amphibians to winter. In 2019, due to the drought, we determined the death of caviar laying in different places of the Lypnyky forest. In one of the locations where thousands of frogs metamorphosis successfully completed ten years ago, spawning of single individuals occurred with complete loss of eggs. Therefore, we have obtained and summarized valuable data for a long period of research, formed a prediction for the population of herb frogs for the future. We believe that once numerous species in the Lypnyky forest, in the next few years will be on the verge of extinction, in some forest quarters completely cease to occur. The instability of the local ecosystem prevents the successful existence of amphibians, which requires two environments in the life cycle - terrestrial for spring and autumn habitat and aquatic for reproduction and wintering.
43
de Boer, Teun P., e Marcel A. G. van der Heyden. "Xenopus connexins: how frogs bridge the gap". Differentiation 73, n. 7 (settembre 2005): 330–40. http://dx.doi.org/10.1111/j.1432-0436.2005.00026.x.
Testo completo
44
Mudke, Madhushri. "Nesting frogs - the breeding biology of Indirana cf. tysoni in the Western Ghats, India". Spring 2021, n. 155, Spring 2021 (1 aprile 2021): 2–7. http://dx.doi.org/10.33256/hb155.27.
Testo completoAbstract (sommario):
Frogs of the genus Indirana are endemic to India. Previous research on these frogs has focussed on taxonomy and systematics but their behaviour remains largely understudied. Here we report the breeding behaviour of Indirana cf. tysoni, including nest building, male to male combat, inguinal amplexus, egg clutch guarding, tadpoles and polymorphism. We also analyse advertisement calls and present a comparative analysis with previously published data. Lastly, we discuss the need to study these breeding behaviours in-depth in order to help frame appropriate conservation plans.
45
Purnamasari, Sry, e Muhammad Wahyu Setiyadi. "PENGARUH ZAT KIMIA PADA BERBAGAI SUHU TERHADAP DENYUT JANTUNG KATAK (Rana sp.) DALAM UPAYA PENGEMBANGAN BUKU PETUNJUK PRAKTIKUM FISIOLOGI HEWAN". Bioscientist : Jurnal Ilmiah Biologi 7, n. 2 (30 dicembre 2019): 123. http://dx.doi.org/10.33394/bjib.v7i2.2388.
Testo completoAbstract (sommario):
The purpose of this study is to determine the effect of chemicals on various temperatures in the heart of frogs (Rana sp.) And to compile valid animal physiology practical instructions. This research is a type of experimental research (true experimental) and this research approach is a qualitative approach. Samples were given 3 different treatments, namely controls with room temperature of 250C-300C, temperature of 00C-100C, and 300C-400C. The results of the study using ANOVA (Analysis of Variance) showed the effect of NaCl solution on the frog heart rate (Rana sp.) Namely Fcount of 5.18 while Ftable of 3.59 so that the results of this study were declared significant. While the effect of saline solution on the frog heart rate (Rana sp.) Is Fcount of 1.78 while Ftable is 3.59 so the results of this study are declared non-significant. So it can be concluded that, NaCl solution at various temperatures significantly influences the frog heart rate (Rana sp.), While saline solution at various temperatures does not significantly influence the frog heart rate (Rana sp.). The process of developing this animal physiology practical guide uses a 3-D development model, which consists of the define, design, and develope stages. The results of the study showed that the practicum instructions for animal physiology were valid, said to be valid because the practicum instructions prepared and developed had met the "valid" criteria.
46
Jaafar, Haryati, e Dzati Athiar Ramli. "Effect of Natural Background Noise and Man-Made Noise on Automated Frog Calls Identification System". Journal of Tropical Resources and Sustainable Science (JTRSS) 3, n. 1 (18 luglio 2021): 208–13. http://dx.doi.org/10.47253/jtrss.v3i1.559.
Testo completoAbstract (sommario):
Frog identification based on their calls becomes important for biological research and environmental monitoring. However, identifying particular frog calls becomes challenging particularly when the frog calls are interrupted with noises either in natural background noise or man-made noise. Hence, an automatic identification frog call system that robust in noisy environment has been proposed in this paper. Experimental studies of 675 audio obtained from 15 species of frogs in the Malaysian forest and recorded in an outdoor environment are used in this study. These audio data are then corrupted by 10dB and 5dB noise. A syllable segmentation technique i.e. short time energy (STE) and Short Time Average Zero Crossing Rate (STAZCR) and feature extraction, Mel-Frequency Cepstrum Coefficients (MFCC) are employed to segment the desired syllables and extract the segmented signal. Subsequently, the Local Mean k-Nearest Neighbor with Fuzzy Distance Weighting (LMkNN-FDW) are employed as a classifier in order to evaluate the performance of the identification system. The experimental results show both of natural background noise and man-made noise outperform by 95.2% and 88.27% in clean SNR, respectively.
47
Carruthers, Vincent. "Ensuring a Future for South Africa's Frogs: a Strategy for Conservation Research". Transactions of the Royal Society of South Africa 66, n. 2 (giugno 2011): 154. http://dx.doi.org/10.1080/0035919x.2011.586444.
Testo completo
48
Carr, Anna, e Donna Hazell. "Talking Frogs: The Role of Communication in Ecological Research on Private Land". Biodiversity and Conservation 15, n. 10 (30 giugno 2006): 3177–91. http://dx.doi.org/10.1007/s10531-005-6969-1.
Testo completo
49
Speers, Claire. "How can teachers effectively use student dialogue to drive engagement with ancient drama? An analysis of a Year 12 Classical Civilisation class studying Aristophanes’ Frogs". Journal of Classics Teaching 21, n. 41 (2020): 19–32. http://dx.doi.org/10.1017/s2058631020000112.
Testo completoAbstract (sommario):
Within this article I aim to explore how greater student dialogue in the classroom can drive engagement with ancient drama. As part of the Classical Civilisation A Level specification, students need to demonstrate knowledge and awareness in the examination of how Aristophanes’ Frogs might have been performed on stage and its possible reception by a classical audience. This research investigates how teachers can effectively encourage student discourse in the classroom for students to engage with and analyse Frogs as a piece of comic drama, rather than simply as an A Level set text.
50
Duffus, Amanda L. J., Trenton W. J. Garner, Richard A. Nichols, Joshua P. Standridge e Julia E. Earl. "Modelling Ranavirus Transmission in Populations of Common Frogs (Rana temporaria) in the United Kingdom". Viruses 11, n. 6 (15 giugno 2019): 556. http://dx.doi.org/10.3390/v11060556.
Testo completoAbstract (sommario):
Ranaviruses began emerging in common frogs (Rana temporaria) in the United Kingdom in the late 1980s and early 1990s, causing severe disease and declines in the populations of these animals. Herein, we explored the transmission dynamics of the ranavirus(es) present in common frog populations, in the context of a simple susceptible-infected (SI) model, using parameters derived from the literature. We explored the effects of disease-induced population decline on the dynamics of the ranavirus. We then extended the model to consider the infection dynamics in populations exposed to both ulcerative and hemorrhagic forms of the ranaviral disease. The preliminary investigation indicated the important interactions between the forms. When the ulcerative form was present in a population and the hemorrhagic form was later introduced, the hemorrhagic form of the disease needed to be highly contagious, to persist. We highlighted the areas where further research and experimental evidence is needed and hope that these models would act as a guide for further research into the amphibian disease dynamics.