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A TEST OF FOOD PARTITIONING BETWEEN THE AQUATIC LARVAE OF TWO PARAPATRIC SPECIES OF TWO-LINED SALAMANDER (EURYCEA BISLINEATA SPECIES COMPLEX) IN A ZONE OF SYMPATRIC CONTACT
Get PDFPhylogenetically related species with similar ecologies often partition resources when in sympatry. Food is an important factor in the co-occurrence of sympatric salamanders, and food partitioning occurs in a variety of sympatric, similar species. Several members of the Two-lined Salamander (Eurycea bislineata) species complex are largely parapatric but co-exist within a narrow zone of sympatric contact. Because larvae of these salamanders frequently occur in very high densities, we tested the hypothesis that larvae of the Blue Ridge Salamander (E. wilderae) and the Southern Two-lined Salamander (E. cirrigera) partition food in sympatry in northeastern Georgia. We predicted that the diets of these two species would differ in sympatry and that the respective diet of each species would differ between allopatric and sympatric populations. Both species fed largely on the aquatic larvae of Trichoptera and Diptera, and their diets reflected the available insect fauna of the respective streams. There was no significant difference between the species in sympatry or between allopatric and sympatric populations of either species. Although we found no evidence of food partitioning, we cannot rule out interspecific competition that may manifest itself in some resource other than food
Geometric Algebra: The “Royal Road” To Quantum Gravity
No full textEuclid is said to have chided Ptolemy I that there is no “royal road” to geometry. Fortunately, there is a “royal road” to quantum gravity – namely, geometric algebra. In geometric algebra, geometrical elements, such as points, vectors, bivectors, ..., up to n-volumes, are represented by matrices. The kind of matrix – dyreal, real, complex, quaternionic, or dyquaternionic – depends only on the metric signature s (the number of spatial dimensions minus the number of temporal dimensions). The rank of the matrix depends only on n, the total number of dimensions, spatial plus temporal. Geometric algebras are periodic in s, but recursive in n. The recursion is generated from the basis vectors of either the Euclidean plane or the Minkowskian plane. The product of these two planes is 4-dimensional space-time if the resulting dimensions are not curled up, but it generates the Standard Model of physics if the resulting dimensions are curled up. Recursive generation leads to an expanding space-time lattice with the Standard Model at each node of the lattice. The rate of the recursion sets the cosmological constant. The other roads of Lee Smolin’s Three Roads to Quantum Gravity, namely M-Theory and Loop Quantum Gravity, can each be expressed as a geometric algebra. By subsuming the alternatives, geometric algebra is indeed the “royal road” to quantum gravity
Cost-Effective Microwave Absorber With Metal Patches
No full textA microwave absorber is fabricated with a single or multilayer dielectric materials covered by metal plane on one side while other side is exposed to free space to absorb microwave signals. In this research, a microwave absorber was designed with a given single layer absorbing material whose dielectric constant was known. In this design process, dielectric constant was controlled by circular metal patches added periodically on the material to achieve desired impedance matching between absorber and free space. 3D electromagnetic simulation software HFSS was used to determine appropriate size and periodicity of metal patches and to evaluate the performance of the designed absorber. Simulation result showed that circular metal patches could improve impedance matching between air and absorber and could tune the absorption frequency. The authors acknowledge the National Science Foundation (Grant # 2000289) for research support
Implementation of a Hairpin model based passive microwave tag using microstrip structure
No full textMicrowave tag is a combination of circuitry utlizing microwave energy to provide a means of identification. A passive microwave tag does not require a battery or power source. We When a passive tag can be enabled for identification and tracking using microwave signal from a distance of several hundred feet. We have developed an elegant and lowcost hairpin model based microwave tag operating around 7 GHz. Our microwave tag can be implemented on a printed circuit board using a mcirostrip structure. This low cost microwave tag can be easily integrated with a plastic package for industrial, scientific and medical purposes due to its smaller size and reduced cost
High-Speed Aerodynamics of Plane Crashes
No full textAirplanes rely on a very special balance of forces on the plane’s fuselage, structure of the wings, and power of the engines. Although this balance can be difficult to achieve at times, flying is one of the safest forms of travel. This is primarily because when mistakes are found in aircraft design, they are fixed across the entire industry worldwide. However, these mistakes are often discovered due to the deaths of passengers and airplane crew. In this poster presentation, we will be examining the high-speed aerodynamic effects that caused a major catastrophe that changed the world of aviation
AN AT-HOME TITRATION USING BAKING SODA, LEMON JUICE, AND MENTOS©.
No full textThe ongoing trend towards increased online and hybrid instruction accelerated during the pandemic. To effectively provide laboratory experiences to students in these modalities it is essential that suitable at-home experiments are developed. In this work, we demonstrate an experiment which can quantify the concentration of citric acid in lemon juice via titration with baking soda without the use of any specialized equipment. Although sodium bicarbonate is a weak base, the gas evolution of carbon dioxide drives the reaction to near completion via Le Chatelier’s Principle. Further, we add the candy Mentos to the analyte during titration which provides a nucleation site for carbon dioxide and ensures the gas evolution is rapid. The cessation of this vigorous gas evolution also provides an easy way to monitor the completion of this acid-base reaction. During the summer of 2021, a group of general chemistry students at Georgia Gwinnett College performed this experiment at-home and compared their results with the traditional in-person titration (performed with sodium hydroxide). The concentration of citric acid determined by the at-home procedure was of 0.20 M (±0.08 M) which was within one standard deviation of the results of the in-person titration (0.25 M (±0.03 M))
THE EFFECTS OF OCEAN ACIDIFICATION ON LARVAL DEVELOPMENT AND SURVIVORSHIP IN LYTECHINUS VARIEGATUS
No full textIn recent decades, increasing atmospheric CO2 levels have contributed to the acidification of the world’s oceans. The absorption of CO2 and associated decrease in pH, cause a decrease in seawater carbonate ion concentrations. Marine organisms, including sea urchins, use calcium carbonate for building critical anatomical structures, without which they cannot survive. Declines in sea urchin populations can have economic and ecological effects, as adult sea urchins are important commercially harvested invertebrates and both larvae and adults play critical roles in maintaining ecological balance in marine habitats. In our study, we focused on larval sea urchins, which are particularly vulnerable to pH changes due to their small size and use of calcium building skeletal elements during critical developmental stages. To understand the effect of acidification on larval sea urchins, green sea urchin (Lytechinus variegatus) larvae were exposed to different pHs in the environmentally realistic range of 7.6-8.4, and the effects on early development and mortality were recorded. Increased developmental abnormalities and mortality were expected in more acidic environments. Our results indicate that the most severe developmental abnormalities and highest mortality occurred in larvae exposed to the lowest pH. These results suggest that acidic seawater, at pH values currently found in the world’s oceans, can adversely affect sea urchin larval development, which can, in turn, have negative ecological and economic impacts
ACCURACY OF MOBILE DEVICE 3D SCANNING APPLICATIONS WHEN MAPPING HUMAN REMAINS IN SIUMLATED CLANDESTINE GRAVES**
No full textWhen assessing human remains upon discovery of a clandestine grave it is important to have a clear and accurate understanding of the spatial context of the scene or site. Furthermore, recording of the remains and their position must be done in a timely manner. Current mapping techniques involve time consuming manual mapping techniques, and expensive LiDAR (Light Detection and Ranging) methods. New advances in technology have seemingly offered an alternative to current methods by the introduction of mobile device 3D scanning applications. However, if the use of these applications is to be adopted in a professional context, the accuracy of such applications must be known to a stateable degree of confidence. Context is important when analyzing human remains in a forensic setting therefore mapping of the scene is required. Conventional mapping methods are time consuming and leave room for human error. High-tech LiDAR methods are expensive and often require a certain degree of expertise to operate confidently. The option of a quick, easy, accurate, and inexpensive method to record the context of a forensic scene may offer an additional tool to agencies that previously had not the expertise or funds to support accurate documentation. Identification of human remains relies largely on quantitative and qualitative data from the remains themselves, but the context in which the remains are found can provide more insight as to the identity of the decedent. This study tests 1) the accuracy and consistency of measurements taken with three of these applications against those taken with conventional methods, 2) ideal conditions (lighting, distance from target area to be scanned, and weather), and 3) whether there a significant reduction of time spent mapping a scene by the use of mobile device-based 3D scanning applications when compared to conventional methods
Size Estimates of the Extinct Marine Snake Pterosphenus schucherti from Eocene-aged Sediments of Central Georgia
Get PDFFossil snakes are most often identified from isolated vertebrae, complicating estimations of total body lengths of extinct taxa. Here we estimate the range of total body length of the late Eocene North American palaeophiid marine snake Pterosphenus schucherti based on 29 recently collected fossil vertebrae from Wilkinson County, Georgia, USA. Previous research suggests that the palaeophiids are most closely related to modern boids. Total body length estimates here are based on family-specific regressions of centrum length versus known total body length in extant members of Boidae, Pythonidae, and Colubridae. The high correlation coefficients for the family specific regressions supports previous studies that used centrum length to estimate total body length in extinct snakes. Here, size estimates for Pterosphenus schucherti ranged from 2.5 to 4.8 m using boids, 3.4 to 13.0 m using pythonids, and 2.8 to 5.3 m using colubrids. This study demonstrates how the lumping of multiple extant clades greatly increases the range of variability for length estimations. For the TL estimates of fossil snakes, it appears that regressions generated from the lowest taxonomic level of the most closely related extant species should be used
OPHIDIOMYCES OPHIDIICOLA INFECTION PREVALENCE IN TIMBER RATTLESNAKES (CROTALUS HORRIDUS LINNEAUS, 1758) FROM THE LOWER PIEDMONT OF CENTRAL GA, USA **
No full textOphidiomyces ophidiicola, the causative agent of Ophidiomycosis, formerly known as Snake Fungal Disease (SFD) is an emerging infection in many species of snakes around the globe. Here, we examine the infection prevalence of Ophidiomyces ophidiicola (Oo) in Timber Rattlesnakes (Crotalus horridus LINNEAUS, 1758) from Cedar Creek Wildlife Management Area (CCWMA) in Putnam Co., Georgia that are part of a long-term radio telemetry study. The CCWMA is a 40,000-acre property within the Oconee National Forest that is characterized by upland Loblolly Pine forests, bottomland hardwood forests, mixed pine-hardwood forests where the previous two associations adjoin, and scattered clear cuts at various secessional stages. The study area is also bisected by a major two-lane highway and a series of smaller paved and unpaved access roads. Both adults from the telemetry study, and neonates born in the lab from females in the same population, were swabbed and will be screened for Oo DNA using quantitative PCR analysis. Based on lesions typically associated with ophydiomycosis present in the adults, we expect to find a high infection prevalence in these animals because of the severity of signs of disease observed. There have been previous reports of vertical transmission of Oo, therefore we cannot rule out infection of the neonates. The emergence of Oo in wild populations of snakes in central Georgia is of concern because Timber Rattlesnakes are in decline for most of their southern range. It is important to understand the dynamics of Oo infection and resultant disease in these animals