Biology Commons^™

Remarkably High And Consistent Tolerance Of A Red Sea Coral To Acute And Chronic Thermal Stress Exposures, Nicolas R. Evensen, Maoz Fine, Gabriela Perna, Christian R. Voolstra, Daniel J. Barshis

Biological Sciences Faculty Publications

Global warming is resulting in unprecedented levels of coral mortality due to mass bleaching events and, more recently, marine heatwaves, where rapid increases in seawater temperature cause mortality within days. Here, we compare the response of a ubiquitous scleractinian coral, Stylophora pistillata, from the northern Red Sea to acute (7 h) and chronic (7-11 d) thermal stress events that include temperature treatments of 27 degrees C (i.e., the local maximum monthly mean), 29.5 degrees C, 32 degrees C, and 34.5 degrees C, and assess recovery of the corals following exposure. Overall, S. pistillata exhibited remarkably similar responses to acute …

Dietary Protein Content And Digestibility Influences Discrimination Of Amino Acid Nitrogen Isotope Values In A Terrestrial Omnivorous Mammal, John P. Whiteman, Mauriel Rodriguez Curras, Kelli L. Feeser, Seth D. Newsome

Biological Sciences Faculty Publications

RATIONALE: Ecologists increasingly determine the δ¹⁵N values of amino acids (AA) in animal tissue; "source" AA typically exhibit minor variation between diet and consumer, while "trophic" AA have increased δ¹⁵N values in consumers. Thus, trophic-source δ¹⁵N offsets (i.e., Δ¹⁵N_T-S) reflect trophic position in a food web. However, even minor variation in δ¹⁵N_{source AA} values may influence the magnitude of offset that represents a trophic step, known as the trophic discrimination factor (i.e., TDF_T-S). Diet digestibility and protein content can influence the δ¹⁵N values …

Tick Extracellular Vesicles Enable Arthropod Feeding And Promote Distinct Outcomes Of Bacterial Infection, Adela S. Oliva Chávez, Xiaowei Wang, Liron Marnin, Nathan K. Archer, Holly L. Hammond, Erin E. Mcclure Carroll, Dana K. Shaw, Brenden G. Tully, Amanda D. Buskirk, Shelby L. Ford, L. Rainer Butler, Preeti Shahi, Kateryna Morozova, Cristina C. Clement, Lauren Lawres, Anya J. O'Neal, Choukri Ben Mamoun, Kathleen L. Mason, Brandi E. Hobbs, Glen A. Scoles, Eileen M. Barry, Daniel E. Sonenshine, Utpal Pal, Jesus G. Valenzuela, Marcelo B. Sztein, Marcela F. Pasetti, Michael L. Levin, Michail Kotsyfakis, Steven M. Jay, Jason F. Huntley, Lloyd S. Miller, Laura Santambrogio, Joao H.F. Pedra

Biological Sciences Faculty Publications

Extracellular vesicles are thought to facilitate pathogen transmission from arthropods to humans and other animals. Here, we reveal that pathogen spreading from arthropods to the mammalian host is multifaceted. Extracellular vesicles from Ixodes scapularis enable tick feeding and promote infection of the mildly virulent rickettsial agent Anaplasma phagocytophilum through the SNARE proteins Vamp33 and Synaptobrevin 2 and dendritic epidermal T cells. However, extracellular vesicles from the tick Dermacentor andersoni mitigate microbial spreading caused by the lethal pathogen Francisella tularensis. Collectively, we establish that tick extracellular vesicles foster distinct outcomes of bacterial infection and assist in vector feeding by acting …

Global Extinction Risk For Seahorses, Pipefishes And Their Near Relatives (Syngnathiformes), Riley A. Pollom, Gina M. Ralph, Caroline M. Pollock, Amanda C.J. Vincent

Biological Sciences Faculty Publications

Few marine taxa have been comprehensively assessed for their conservation status, despite heavy pressures from fishing, habitat degradation and climate change. Here we report on the first global assessment of extinction risk for 300 species of syngnathiform fishes known as of 2017, using the IUCN Red List criteria. This order of bony teleosts is dominated by seahorses, pipefishes and seadragons (family Syngnathidae). It also includes trumpetfishes (Aulostomidae), shrimpfishes (Centriscidae), cornetfishes (Fistulariidae) and ghost pipefishes (Solenostomidae). At least 6% are threatened, but data suggest a mid-point estimate of 7.9% and an upper bound of 38%. Most of the threatened species are …

Diet Of Long-Eared Owl And Common Kestrel In An Urban Landscape (Ukraine), Ivan Zahorodnyi, Oleksii Dubovyk, Ivan Komarnytskyi, Ihor Dykyy

Biological Sciences Faculty Publications

In the present study we performed a comparative dietary analysis of two predatory birds, the Long-eared Owl (Asio otus) and the Common Kestrel (Falco tinnunculus) in the district of Lviv city. We found that the Long-eared Owl and the Common Kestrel are typical small mammal specialists within the urban ecosystem. Considering the abundance and biomass of prey, small mammals comprise 98.4% of the Long-eared Owl’s diet. The species composition of mammals coincides almost 50% in the food intake comparison of the two birds. It has been established that the main prey of both species is the …

Consensus Guidelines For Advancing Coral Holobiont Genome And Specimen Voucher Deposition, Christian R. Voolstra, Kate M. Quigley, Sarah W. Davies, John Everett Parkinson, Raquel S. Peixoto, Manuel Aranda, Andrew C. Baker, Adam R. Barno, Daniel J. Barshis, Francesca Benzoni, Victor Bonito, David G. Bourne, Carol Buitrago-López, Tom C.L. Bridge, Cheong Xin Chan, David J. Combosch, Jamie Craggs, Jörg C. Frommlet, Santiago Herrera, Andrea M. Quattrini, Till Röthig, James D. Reimer, Esther Rubio-Portillo, David J. Suggett, Helena Villela, Maren Ziegler, Michael Sweet

Biological Sciences Faculty Publications

Coral research is being ushered into the genomic era. To fully capitalize on the potential discoveries from this genomic revolution, the rapidly increasing number of high-quality genomes requires effective pairing with rigorous taxonomic characterizations of specimens and the contextualization of their ecological relevance. However, to date there is no formal framework that genomicists, taxonomists, and coral scientists can collectively use to systematically acquire and link these data. Spurred by the recently announced “Coral symbiosis sensitivity to environmental change hub” under the “Aquatic Symbiosis Genomics Project” - a collaboration between the Wellcome Sanger Institute and the Gordon and Betty Moore Foundation …

Spatio-Temporal Modelling Of Tick Life-Stage Count Data With Spatially Varying Coefficients, Thabo Lephoto, Henry Mwambi, Oliver Bodhlyera, Holly Gaff

Biological Sciences Faculty Publications

There is a vast amount of geo-referenced data in many fields of study including ecological studies. Geo-referencing is usually by point referencing; that is, latitudes and longitudes or by areal referencing, which includes districts, counties, states, provinces and other administrative units. The availability of large geo-referenced datasets for modelling has necessitated the development and application of spatial statistical methods. However, spatial varying coefficients models exploring the abundance of tick counts remain limited. In this study we used data that was collected and prepared by researchers in the Department of Biological Sciences from the Old Dominion University, Virginia, USA. We modelled …

Variation In Coral Thermotolerance Across A Pollution Gradient Erodes As Coral Symbionts Shift To More Heat-Tolerant Genera, Melissa S. Naugle, Thomas A. Oliver, Daniel J. Barshis, Ruth D. Gates, Cheryl A. Logan

Biological Sciences Faculty Publications

Phenotypic plasticity is one mechanism whereby species may cope with stressful environmental changes associated with climate change. Reef building corals present a good model for studying phenotypic plasticity because they have experienced rapid climate-driven declines in recent decades (within a single generation of many corals), often with differential survival among individuals during heat stress. Underlying differences in thermotolerance may be driven by differences in baseline levels of environmental stress, including pollution stress. To examine this possibility, acute heat stress experiments were conducted on Acropora hyacinthus from 10 sites around Tutuila, American Samoa with differing nutrient pollution impact. A threshold-based heat …

Self And Microbiota-Derived Epitopes Induce Cd4⁺ T Cell Anergy And Conversion Into Cd4⁺Foxp3⁺ Regulatory Cells, Michal P. Kuczma, Edyta A. Szurek, Anna Cebula, Vu L. Ngo, Maciej Pietrzak, Piotr Kraj, Timothy L. Denning, Leszek Ignatowicz

Biological Sciences Faculty Publications

The physiological role of T cell anergy induction as a key mechanism supporting self-tolerance remains undefined, and natural antigens that induce anergy are largely unknown. In this report, we used TCR sequencing to show that the recruitment of CD4⁺CD44⁺Foxp3⁻CD73⁺FR4⁺ anergic (Tan) cells expands the CD4⁺Foxp3⁺ (Tregs) repertoire. Next, we report that blockade in peripherally-induced Tregs (pTregs) formation due to mutation in CNS1 region of Foxp3 or chronic exposure to a selecting self-peptide result in an accumulation of Tan cells. Finally, we show that microbial antigens from Akkermansia muciniphila …

Polar Bear Behavior: Morphologic And Physiologic Adaptations, John P. Whiteman

Biological Sciences Faculty Publications

Polar bears possess morphologic and physiologic characteristics that reflect their terrestrial lineage as members of the bear family (Ursidae) as well as adaptations to the Arctic marine environment. Among marine mammals, they are the least adapted for aquatic life. They exhibit substantial seasonality in body mass, body condition, and many physiological functions, reflecting the annual cycle of both their Arctic sea ice habitat and the availability of their main prey, ringed seals. This hypercarnivorous diet has likely influenced the polar bear’s craniodental morphology and nutritional physiology. Similar to other marine mammal predators, polar bears exhibit a relatively high resting metabolic …

Incorporation Of Summer Annual Mixtures Into Grazing Systems In Kentucky, Kelly Marie Mercier

Theses and Dissertations--Plant and Soil Sciences

Utilizing summer annual grass-legume forage mixtures has the potential to improve forage yield and nutritive characteristics, and/or animal performance during times when cool-season pasture growth is limited by high temperatures. Legumes can utilize atmospheric nitrogen, which can increase crude protein and forage digestibility in mixtures. As nitrogen application generally improves both the yield and nutritive characteristics of summer annual forages, but can have a negative effect on legume competitiveness, nitrogen fertilizer recommendations for legume-containing summer annual mixtures are not well established.

Two experiments were conducted to determine the feasibility of utilizing summer annual mixtures in Kentucky, USA. The first experiment …

Lessons From Four Decades Of Monitoring Vegetation And Fire: Maintaining Diversity And Resilience In Florida's Uplands, Warren G. Abrahamson Ii, Christy R. Abrahamson, Matthew A. Keller

Faculty Journal Articles

Worldwide, humans are altering the fire regimes of fire-prone ecosystems. Efforts to restore fire regimes in natural areas are usually guided by fire-management plans (FMP) using prescribed burning. We assessed an FMP by repeatedly sampling 11 Florida uplands impacted by 2 to 11 fires each during a 38-year period. Stands exhibited ecological resilience with little plant composition change and modest abundance shifts. Resilience was not eroded by repeated FMP-prescribed fires. Species richness and diversity were significantly higher at the end vs. beginning of our study, suggesting that FMP-applied fire regimes are within the range of those with which species evolved. …

The Effects Of Food Supply On Reproductive Hormones And Timing Of Reproduction In An Income-Breeding Seabird, Shannon Whelan, Scott A. Hatch, Z. Morgan Benowitz-Fredericks, Charline Parenteau, Olivier Chastel, Kyle Elliott

Faculty Journal Articles

Current food supply is a major driver of timing of breeding in income-breeding animals, likely because increased net energy balance directly increases reproductive hormones and advances breeding. In capital breeders, increased net energy balance increases energy reserves, which eventually leads to improved reproductive readiness and earlier breeding. To test the hypothesis that phenology of income-breeding birds is independent of energy reserves, we conducted an experiment on food-supplemented (“fed”) and control female black-legged kittiwakes (Rissa tridactyla). We temporarily increased energy costs (via weight handicap) in a 2 × 2 design (fed/unfed; handicapped/unhandicapped) during the pre-laying period and observed movement …

There’S More Than One Way To Beat The Heat: What Anal Probes Reveal About Thermal Responses In Neotropical Beetles (Coleoptera: Cerambycidae)., Emilie I. Dion

Dissertations and Theses

Increasing global temperatures have been linked to shifts in the distributions and preferred microhabitats of terrestrial species. This trend is predicted to impact tropical forest insects, which may already be exposed to conditions that bring them close to their thermal maxima. Tropical microhabitats are linked to vertical stratification, because the canopy is hotter, winder, and less humid than the ground. In ectothermic organisms, such as beetles, thermoregulation is dependent on morphological and behavioral traits. This study investigates woodboring cerambycid beetles, to determine how behavioral thermoregulation through microhabitat selection (vertical stratification) is correlated to morphological attributes (color lightness, size, and pubescence) …

Analyzing Ultrastructural Characteristics Of Post-Synaptic Targets Of Pre-Identified Presynaptic Boutons In Layer 3 And Layer 4 Of The Ferret Primary Visual Cortex, Donia Shehab

Dissertations and Theses

The purpose of this study was to analyze the size and ultrastructural characteristics of post-synaptic elements apposed to previously characterized pre-synaptic elements in layers 3 and 4 of the primary visual cortex (PVC). We are aiming to quantify a range of values for synaptic element morphologies as well as to correlate pre- and post-synaptic elements to find a set of rules that is prevalent in the visual cortex that can also be upheld in other mammals. We hypothesize that bigger pre-synaptic elements correlate to bigger synapses and bigger post-synaptic elements. We compared these two different layers because they receive synaptic …

Geometric Morphometric Analyses Define Riverine And Lacustrine Species Flocks Of Himalayan Snowtrout (Cyprinidae: Schizothorax) In Nepal, Binod Regmi, Marlis R. Douglas, David R. Edds, Michael E. Douglas

Biological Sciences Faculty Publications and Presentations

Freshwater fishes in the river and lake systems in the Himalayas and Tibetan Plateau are morphologically diverged but the evolutionary relationship of putative subspecies separated in these freshwater systems has not been explored. Snowtrout (Schizothorax spp.) are minnows (Cyprinidae) broadly distributed in Asia. Body shapes of 3 Lake Rara (northwest Nepal) endemics (S. macrophthalmus, S. nepalensis, S. raraensis) and 2 widely distributed riverine species (S. progastus, S. richardsonii) across 3 drainages in Nepal (i.e. Karnali, Gandaki, and Koshi Rivers) were studied using geometric morphometry. Data were derived from museum voucher specimens/tissues collected …

Searching For Gold: Using A Novel Land Cover Classification To Identify Multiscale Drivers Of Site Occupancy By A Flagship Species For Early-Successional Habitat Conservation, Baron Lin

Theses and Dissertations

Understanding habitat selection at multiple scales is an important step in guiding conservation programs and reversing species declines. This, however, is difficult for species that occupy early-successional habitats (ESH) due to a lack of accurate representation of shrub cover in publicly available land cover data. The Golden-winged Warbler (Vermivora chrysoptera; GWWA) is a threatened species of conservation concern and a flagship for ESH conservation. We used a novel, LIDAR-derived land cover classification that accurately identifies shrubs at a fine resolution (1m) to investigate how habitat composition and configuration influence GWWA site occupancy. We aggregated this same land cover …

Modeling Vegetation Effects On Barrier Island Evolution, Eric W. Schoen

Theses and Dissertations

Barrier islands play a significant role in protecting coastlines and harboring coastal habitats. In an effort to study and better understand the evolution of barrier island systems, a cellular model capturing various meteorological and environmental processes is proposed. Erosion due to wind, gravity, and marine processes are coupled with plant population effects. We demonstrate the inhibition of plant cover on sediment mobility, island migration, and erosion in the presence of sea level rise.

Validating The Methods And Assays Necessary For Establishing An Effective In Vitro Lung Cancer Transformation Model, Crystal Turner

Theses and Dissertations

In my research, I developed tools and performed assays to study the in vitro transformation of immortalized lung epithelial cells by oncogenic KRAS^G12V. I delivered the KRAS by transfection and lentiviral transduction, and after confirming the cells expressed KRAS, I evaluated transformation using several experimental approaches including monitoring of EMT markers and various types of growth assays. I also conducted preliminary experiments that quantified sphingolipid alterations in the cells that had markers indicative of having gone through EMT. The goal of these experiments was to assess whether sphingolipids are altered in cells that are transformed in vitro by …

Impact Of Targeting Glycosylated Ceramides On Tumorigenic Properties, And Characterization Of Sphingolipids In Head And Neck Tumors, Katherine E. Hylton

Theses and Dissertations

Sphingolipids play a crucial role in signaling, membrane structure, and migration, making them important molecules in cancer development, metastasis, and drug resistance. While some sphingolipids have been associated with pro-apoptotic or pro-survival behaviors, the role of many sphingolipids in cancer remains poorly defined. Chapter 1 of this study investigated the impact of three enzymes that compose most of the ceramide to Lc3 ceramide pathway – UGCG, GBA, and B3GNT5 – and how their alteration impacts chemoresistance and basal membrane invasion in vitro. It was found that the CΒE-induced inhibition of GBA, which converts glucosylceramide to ceramide, has no effects on …

Water Clarity At The River-Estuary Transition Zone: A Comparative Study Of The James, Mattaponi, And Pamunkey Sub-Estuaries, Rachel Henderson

Theses and Dissertations

Water clarity is a key parameter for monitoring water quality and often used to assess habitat suitability for submerged aquatic vegetation (SAV). Light attenuation, a measure of water clarity, is impacted by colored dissolved organic matter (CDOM), and by suspended particulates which include living and non-living components. We anticipated that the relative importance of these factors in regulating light attenuation would vary among the upper portions of three sub-estuaries differing in morphometry, hydrology, and degree of human influence. The James is characterized by eutrophic conditions and high algal abundance, whereas the Mattaponi and Pamunkey exhibit lower phytoplankton production. The Mattaponi …

Larval Anatomy Of Monotypic Painted Ant Nest Frogs Lithodytes Lineatus Reveals Putative Homoplasies With The Leptodactylus Pentadactylus Group (Anura: Leptodactylidae), Filipe A.C Do Nascimento, Rafael O. De Sá, Paulo C. De A. Garcia

Biology Faculty Publications

The morphological diversity of anuran larvae made them an important source of information for evolutionary and systematic studies. For the monotypic frog genus Lithodytes, which has an interesting taxonomic history, including its past synonymizing with Adenomera and its placement as a subgenus of Leptodactylus, the information provided from its larvae can help to understand its systematics interrelationships and also provide insights about its evolutionary trajectories. Herein, we provide a detailed description of the larval morphology of Lithodytes lineatus, including novel data of internal morphology (buccopharyngeal cavity and skeleton), and discuss some morphological and evolutionary aspects in relation …

A Functional Genomics Screen Identifying Blood Cell Development Genes In Drosophila By Undergraduates Participating In A Course-Based Research Experience, Cory J. Evans, John M. Olson, Bama Charan Mondal, Pratyush Kandimalla, Ariano Abbasi, Mai M. Abdusamad, Osvaldo Acosta, Julia A. Ainsworth, Haris M. Akram, Ralph B. Albert, Elitzander Alegria-Leal, Kai Y. Alexander, Angelica C. Ayala, Nataliya S. Balashova, Rebecca M. Barber, Harmanjit Bassi, Sean P. Bennion, Miriam Beyder, Kush V. Bhatt, Chinmay Bhoot, Aaron W. Bradshaw, Tierney G. Brannigan, Boyu Cao, Yancey Y. Cashell, Timothy Chai, Alex W. Chan, Carissa Chan, Inho Chang, Jonathan Chang, Michael T. Chang, Patrick W. Chang, Stephen Chang, Neel Chari

Biology Faculty Works

Undergraduate students participating in the UCLA Undergraduate Research Consortium for Functional Genomics (URCFG) have conducted a two-phased screen using RNA interference (RNAi) in combination with fluorescent reporter proteins to identify genes important for hematopoiesis in Drosophila. This screen disrupted the function of approximately 3500 genes and identified 137 candidate genes for which loss of function leads to observable changes in the hematopoietic development. Targeting RNAi to maturing, progenitor, and regulatory cell types identified key subsets that either limit or promote blood cell maturation. Bioinformatic analysis reveals gene enrichment in several previously uncharacterized areas, including RNA processing and export and vesicular …

Characterizing Industrial And Artisanal Fishing Vessel Catch Composition Using Environmental Dna And Satellite-Based Tracking Data, Demian A. Willette, Gabriela Navarrete-Forero, Zachary Gold, Apollo Marco D. Lizano, Leonardo Gonzalez-Smith, Giovanna Sotil

Biology Faculty Works

The decline in wild-caught fisheries paired with increasing global seafood demand is pushing the need for seafood sustainability to the forefront of national and regional priorities. Validation of species identity is a crucial early step, yet conventional monitoring and surveillance tools are limited in their effectiveness because they are extremely time-consuming and require expertise in fish identification. DNA barcoding methods are a versatile tool for the genetic monitoring of wildlife products; however, they are also limited by requiring individual tissue samples from target specimens which may not always be possible given the speed and scale of seafood operations. To circumvent …

Stomatal Conductance And Reed Canary Grass Suppression Traits Of Native Michigan Trees, David E. Martinez, Martin L. Vanderschoot, Dave Warners

Student Papers and Reports

Reed canary grass (Phalaris arundinacea), a prominent invasive understory species, threatens native Michigan biodiversity statewide. A notable affected area includes a stretch of agricultural land along Schooley Drain in Caledonia, MI, located in the headwaters of the Plaster Creek watershed. Our study pursues the following questions: “Do native trees provide enough shade to reduce the growth of Reed canary grass?” and “Which native trees best transpire water from a floodplain?”: To answer these questions, we initiated a long term evaluation of seven different species of native Michigan trees to investigate which species best inhibits the growth of reed …

Testing The Effect Of Aquarium-Based Learning On Patron Acceptance Of Evolutionary Theory, Jamie Jensen, Ethan R. Tolman, Spencer G. Shumway, Liam S. Williams

ScholarsArchive Data

This is data collected prior to and directly following an intervention at a public aquarium in Idaho surrounding the reconciliation of evolution with religious audiences.

Stomatal Conductance And Reed Canary Grass Suppression Of Native Michigan Trees, David E. Martinez Vasquez, Martin L. Vanderschoot, David Warners

Faculty and Professional Research

Reed canary grass (Phalaris arundinacea), a prominent invasive understory species, threatens native Michigan biodiversity statewide. A notable affected area includes a stretch of agricultural land along Schooley Drain in Caledonia, MI, located in the headwaters of the Plaster Creek watershed. Our study pursues the following questions: “Do native trees provide enough shade to reduce the growth of Reed canary grass?” and “Which native trees best transpire water from a floodplain?”: To answer these questions, we initiated a long-term evaluation of seven different species of native Michigan trees to investigate which species best inhibits the growth of reed canary grass and …

Plaster Creek Floodplain And Adjacent Ravines Near Stanaback Park: Botanical Inventory Highlights And Management Considerations, David Warners, Garrett Crow, Haley Weesies

Faculty and Professional Research

In the summer of 2021, the research team visited this area of ravines and floodplain a total of twenty-one times to conduct our field research. During the visits, they carefully walked throughout different sections of the study site, identifying each vascular plant species they saw growing there and observing how the flora developed throughout the season. In addition to keeping detailed field notes, they documented permanent records of the findings of our inventory by collecting voucher specimens that have been deposited in the Calvin University Herbarium. Additionally, they sent duplicate specimens to the Michigan State University Herbarium and/or University of …

Botanical Inventory Highlights And Management Considerations For Covenant Park, David Warners, Garrett Crow, Haley Weesies

Faculty and Professional Research

In the spring and summer of 2021, Calvin University students and faculty conducted a botanical inventory and assessment of the natural areas in Covenant Park, located at 3724 Shaffer Avenue SE, Kentwood, MI 49512. Given that the property was recently acquired by the City of Kentwood Parks & Recreation, the purpose of this inventory is to inform Kentwood Parks and Recreation staff about the site’s floristic quality, diversity, and ecological significance. The specific objectives of this study are to 1) provide a comprehensive inventory of the species of plants occurring on the property, 2) identify particular areas that would benefit …

Identification Of Compounds Causing Cellular Autofluorescence In Touch Samples, Elora C. Wall

Master of Science in Forensic Science Directed Research Projects

As DNA analysis has advanced and produced tests with higher sensitivities, attention has turned toward obtaining DNA profiles from cells left with fingermarks. Recent studies have reported that cells deposited within fingermarks can exhibit differences in autofluorescence emission in the ‘red’ region of the visible spectrum (e.g., between 650-670 nm), which can be used to differentiate contributor cell population and separate them before DNA profiles. Interestingly, this emission was not consistent to the individual day-to-day and likely not a genetically-controlled attribute of the contributor. Instead, this emission signature results from extended exposure of the skin to certain materials such as …