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2011

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Articles 391 - 420 of 10326

Full-Text Articles in Physical Sciences and Mathematics

Spring Migration Of Mallards From Arkansas As Determined By Satellite Telemetry, David George Krementz, Kwasi Asante, Luke W. Naylor Dec 2011

Spring Migration Of Mallards From Arkansas As Determined By Satellite Telemetry, David George Krementz, Kwasi Asante, Luke W. Naylor

United States Geological Survey: Staff Publications

We used satellite telemetry to document spring migration phenology, routes, stopover regions, and nesting sites of mallards Anas platyrhynchos marked in Arkansas during the winters of 2004–2007. Of the 143 marked mallards that migrated from Arkansas, they did so, on average, by mid-March. Mallards flew over the Missouri Ozarks and 42% made an initial stopover in Missouri, where they used areas that had larger rivers (Mississippi River, Missouri River) embedded in an agricultural landscape. From this stopover region they either migrated directly to the Prairie Pothole Region (PPR) or they migrated north to Minnesota where they either moved next to …


Notes On The Distribution Of Eastern Woodrats And Hispid Cotton Rats In South-Central Nebraska, Heather D. Wills, Keith Geluso, Eric J. Smits, Joseph T. Springer, Wesley E. Newton Dec 2011

Notes On The Distribution Of Eastern Woodrats And Hispid Cotton Rats In South-Central Nebraska, Heather D. Wills, Keith Geluso, Eric J. Smits, Joseph T. Springer, Wesley E. Newton

The Prairie Naturalist

The eastern woodrat (Neotoma floridana) and hispid cotton rat (Sigmodon hispidus) reach distributional limits in southern Nebraska (Jones 1964, Farney 1975). In the last half-century, both species have expanded their distributional ranges in the region (Kugler and Geluso 2009, Wright et al. 2010). Herein, we report new localities of occurrence for both species that extend known distributional boundaries in south-central Nebraska beyond those reported by Kugler and Geluso (2009) and Wright et al. (2010).

Associated with other studies, we captured small mammals in Sherman live-traps in south-central Nebraska. Voucher specimens were deposited in collections at the …


Patterns Of Age-0 Gizzard Shad Abundance And Food Habits In A Nebraska Irrigation Reservoir, Christopher L. Sullivan, Casey W. Schoenebeck, Keith D. Koupal, W. Wyatt Hoback, Brian C. Peterson Dec 2011

Patterns Of Age-0 Gizzard Shad Abundance And Food Habits In A Nebraska Irrigation Reservoir, Christopher L. Sullivan, Casey W. Schoenebeck, Keith D. Koupal, W. Wyatt Hoback, Brian C. Peterson

The Prairie Naturalist

Gizzard shad (Dorosoma cepedianum) are prolific spawners that can influence reservoir communities. Larval gizzard shad may compete with larval recreational fish for zooplankton resources. Therefore, it is necessary to determine larval gizzard shad dynamics and food habits to better understand their potential for competition with larval recreational fish. Our study examined age-0 gizzard shad abundance in Harlan County Reservoir during late spring/summer from 2002–2010 and food habits and prey electivity of age-0 gizzard shad during late spring/summer 2008 and 2009. The annual peak age-0 gizzard shad density 3 from 2002–2010 ranged from 50 to 380/100 m , which …


Late Seasonal Captures Of The Plains Pocket Mouse (Perognathus Flavescens) In Iowa, Hans W. Otto, Jeremy A. White Dec 2011

Late Seasonal Captures Of The Plains Pocket Mouse (Perognathus Flavescens) In Iowa, Hans W. Otto, Jeremy A. White

The Prairie Naturalist

The plains pocket mouse, Perognathus flavescens, is a nocturnal granivore that inhabits friable soils in sparsely vegetated areas (Monk and Jones 1996). In the United States, the distribution of the plains pocket mouse extends from Arizona, New Mexico, and Texas through the Great Plains to North Dakota and Minnesota (Hall 1981). This species reaches its easternmost limits in Iowa, where it has been documented from a limited number of grassland sites in eastern, central, and western parts of the state (Bowles 1975, Wilson et al. 1996). Due to loss of grassland habitat, the plains pocket mouse is currently listed …


Book Review: Effects Of Climate Change On Birds, Edited By Anders Pape Meller, Wolfgang Fiedler, And Peter Berthold, Brian J. Olsen Dec 2011

Book Review: Effects Of Climate Change On Birds, Edited By Anders Pape Meller, Wolfgang Fiedler, And Peter Berthold, Brian J. Olsen

The Prairie Naturalist

Book review of Effects of Climate Change on Birds, edited by Anders Pape Meller, Wolfgang Fiedler, and Peter Berthold.

Climate scientists from across the globe predict vast changes during the next century in the planet's temperatures, precipitation, storm intensities, fire regimes, hydrologic cycles, and atmospheric, water, and soil chemistries. The changes will be global, but their effects will be felt locally everywhere. To find a scientifically and socially engaging bellwether of these events, we need to look only through the lens of avian biology. Birds are found from pole to pole; their movements connect continents. They are loud, colorful …


Review Of Teaching Children Science: Hands-On Nature Study In North America, 1890-1930 By Sally Kohlstedt, Meena M. Balgopal Dec 2011

Review Of Teaching Children Science: Hands-On Nature Study In North America, 1890-1930 By Sally Kohlstedt, Meena M. Balgopal

The Prairie Naturalist

Many scientists and educators agree that the goal of science education is to prepare students "to know, use and interpret scientific explanations of the natural world," as cited in the National Research Council publication, Taking Science to School: Learning and Teaching Science in Grades K-8 (DuschI et al. 2007). Yet, many science instructors of K-12 and post-secondary students often rely on teacher-telling modes of pedagogy and neglect to engage their students in natural inquiry and scientific study that model the research methods used by scientists. As a result, many young people are not aware of how scientists make discoveries about …


Genetic Structure Of Grass Carp Populations In The Missouri And Mississippi River Basins, Usa, Bobbi M. Adams, Katie N. Bertrand, Michael L. Brown, Donald Auger Dec 2011

Genetic Structure Of Grass Carp Populations In The Missouri And Mississippi River Basins, Usa, Bobbi M. Adams, Katie N. Bertrand, Michael L. Brown, Donald Auger

The Prairie Naturalist

We provided an early characterization of the genetic structure of the grass carp (Ctenopharyngodon idella) population as it expands its distribution in both the Missouri and Mississippi River basins. Further, we provided initial comparisons of allelic richness at 17 polymorphic microsatellite markers between 56 grass carp from the USA, and six from the Yangtze River in China. The number of alleles per locus ranged from two to eight and size ranges of alleles for fish collected from the invaded and native ranges were similar (P ≤ 0.001; 107–226 bp) to those previously reported in the literature. Distance-based clustering …


Massasauga Repatriation On A Restored Wet Prairie, Francis E. Durbian, Brian N. Lomas, Jeff Briggler, Paul Mckenzie, Tom Nagel Dec 2011

Massasauga Repatriation On A Restored Wet Prairie, Francis E. Durbian, Brian N. Lomas, Jeff Briggler, Paul Mckenzie, Tom Nagel

The Prairie Naturalist

The massasauga (Sistrurus catenatus) is a small rattlesnake that occurs from Texas to New York (Schmidt and Davis 1941, Conant and Collins 1991, Szymanski 1998). In Missouri, the Eastern massasauga rattlesnake (EMR; S. c. catenatus), a subspecies of the massasauga, occurs north and east of the Missouri River, is a former candidate for listing under the United States Endangered Species Act (Code of Federal Regulations 64 FR 57534; Szymanski 1998), and is listed as a state endangered species (Missouri Natural Heritage Program 2011). Missouri currently harbors five extant EMR populations (Johnson 2000, Durbian et al., unpublished report, …


Book Review Of Encyclopedia Of Biological Invasions, Edited By Daniel Simberloff And Marcel Rejmanek, Qinfeng Guo Dec 2011

Book Review Of Encyclopedia Of Biological Invasions, Edited By Daniel Simberloff And Marcel Rejmanek, Qinfeng Guo

The Prairie Naturalist

Book review of Encyclopedia of Biological Invasions, edited by Daniel Simberloff and Marcel Rejmanek.

Species introductions and consequent biotic invasions and homogenization are major components of global change that are drawing increasing concern and various levels of actions and reactions around the world. Invasion ecology has advanced rapidly during the last few decades, and the discipline is now increasingly integrated with the social and economic sciences. A better understanding of the invasion process and its effects is thus clearly needed. For basic research, invasion biology offers fascinating and sometimes unique opportunities for testing certain ecological or evolutionary theories and …


Depth And Littoral Habitat Association Of Age-0 Yellow Perch In Two South Dakota Glacial Lakes, Daniel J. Dembkowski, Melissa R. Wuellner, David W. Willis Dec 2011

Depth And Littoral Habitat Association Of Age-0 Yellow Perch In Two South Dakota Glacial Lakes, Daniel J. Dembkowski, Melissa R. Wuellner, David W. Willis

The Prairie Naturalist

Yellow perch (Perca flavescens) are a recreationally important species and represent a key ecological component of glacial lake littoral fish assemblages (Stone 1996, Blackwell et al. 1999). Research has shown a generalized pattern of juvenile (age-0) yellow perch spatial distribution wherein larvae hatch in near-shore areas, migrate to limnetic areas where they remain for approximately 40 d, and then return to demersal behaviors and within near-shore littoral habitats (Noble 1975, Whiteside et al. 1985). However, anomalous distribution and habitat use by age-0 yellow perch has been observed in South Dakota glacial lakes (Fisher and Willis 1997) and the …


Northern Harrier Hatches Mallard Nest, Jeffery W. Stackhouse, Benjamin A. Geaumont Dec 2011

Northern Harrier Hatches Mallard Nest, Jeffery W. Stackhouse, Benjamin A. Geaumont

The Prairie Naturalist

The northern harrier (Circus cyaneus) is a widespread raptor commonly found nesting throughout the Northern Great Plains. Northern harriers forage primarily on small mammals and passerines with the males providing the majority of prey to nestlings until 14–28 days of age (Redpath et al. 2006, Vukovich and Ritchison 2006). Although the genus Circus is known to predate eggs from nest of many nesting birds (Hiraldo et al. 1975, Donaszar et al. 1996, Opermanis et al. 2000), few have been recorded commandeering nests of different species (Laine 1928, Fleskes 1992). In June 2010, we observed a northern harrier that …


Review Of Sandhill And Whooping Cranes: Ancient Voices Over America's Wetlands\ By Paul Johnsgard, Jane Austin Dec 2011

Review Of Sandhill And Whooping Cranes: Ancient Voices Over America's Wetlands\ By Paul Johnsgard, Jane Austin

The Prairie Naturalist

Paul Johnsgard has long been captivated by wild cranes and their unique vocalizations, courtship dances, and wide-ranging migrations. As a scientist and an admirer, Johnsgard has watched their migrations and behaviors for decades as hundreds of thousands of cranes staged each spring by the central Platte River, not far from his home in Lincoln, Nebraska. As an artist, he has skillfully captured their courtship dances and other behaviors in his exceptional line drawings. And, as an author, he has written extensively on their ecology in three earlier books: Cranes of the World (1983), Those of the Gray Wind: The Sandhill …


Comparison Of Fish Communities In Recently Constructed Side-Channel Chutes With The Main Stem Missouri River, Kasey Whiteman, Vincent H. Travnichek, Darrick L. Garner, Brandon Eder, Kirk Steffensen Dec 2011

Comparison Of Fish Communities In Recently Constructed Side-Channel Chutes With The Main Stem Missouri River, Kasey Whiteman, Vincent H. Travnichek, Darrick L. Garner, Brandon Eder, Kirk Steffensen

The Prairie Naturalist

Two United States Army Corp of Engineers- (USACE) funded projects were conducted from 2006 to 2008 along the Missouri River to monitor fish communities in recently constructed side-channel chutes and to monitor pallid sturgeon (Scaphirhynchus albus) and the associated fish assemblage in the main stem Missouri River. Data from both monitoring projects were compared to evaluate fish assemblages among four mitigated habitats (e.g., constructed side-channel chutes) and the main-stem Missouri River. Chutes had a greater overall number of species (n = 59) and higher species richness (Margalef’s index = 5.81), but richness was not different (F1, 4 = …


Baryon Spectrum Analysis Using Dirac's Covariant Constraint Dynamics, Joshua Franklin Whitney Dec 2011

Baryon Spectrum Analysis Using Dirac's Covariant Constraint Dynamics, Joshua Franklin Whitney

Doctoral Dissertations

We determine the energy spectrum of the baryons by treating each of them as a three-body system with the interacting forces coming from a set of two-body potentials that depend on both the distance between the quarks and the spin and orbital angular momentum coupling terms. We first review constraint dynamics for a relativistic two-body system in order to assemble the necessary two body framework for the three-body problem. We review the different types of covariant two-body interactions involved in constraint dynamics, including vector and scalar, and solve the problem of energy eigenstates using constraint dynamics. We use the Two …


Dendroclimatology And Woodland Dynamics On The Volcanic Badlands Of Western New Mexico, U.S.A., Mark Daniel Spond Dec 2011

Dendroclimatology And Woodland Dynamics On The Volcanic Badlands Of Western New Mexico, U.S.A., Mark Daniel Spond

Doctoral Dissertations

My dissertation research addressed woodland dynamics and dendroclimatology on the volcanic badlands of western New Mexico. The research was intended to complement previous studies by: (1) assessing vegetation structure and composition dynamics at El Malpais National Monument between 1948–2010 using repeat photography; (2) improving knowledge of the influence of climate and land use on vegetation dynamics at El Malpais National Monument; (3) providing a unique tree-ring data set from Rocky Mountain juniper growing on the malpais; (4) elucidating relationships between Pacific teleconnections and radial growth in Rocky Mountain juniper; and (5) improving understanding of the dynamic nature of climate in …


Environmental Influences On Juvenile Fish Abundances In A River-Dominated Coastal System, Laure Carassou, Brian Dzwonkowski, Frank J. Hernandez, Jr., Sean P. Powers, William M. Graham, Kyeong Park, John Mareska Dec 2011

Environmental Influences On Juvenile Fish Abundances In A River-Dominated Coastal System, Laure Carassou, Brian Dzwonkowski, Frank J. Hernandez, Jr., Sean P. Powers, William M. Graham, Kyeong Park, John Mareska

University Faculty and Staff Publications

We investigated the influence of climatic and environmental factors on variations in juvenile abundances of marine fishes in a river-dominated coastal system of the north-central Gulf of Mexico, where an elevated primary productivity sustains fisheries of high economic importance. Fish were collected monthly with an otter trawl at three stations near Mobile Bay from 1982 to 2007. Fish sizes were used to isolate juvenile stages within the data set, and monthly patterns in juvenile fish abundance and size were then used to identify seasonal peaks for each species. The average numbers of juvenile fish collected during these seasonal peaks in …


The Valuation Of User-Generated Content: A Structural, Stylistic And Semantic Analysis Of Online Reviews, Noi Sian Koh Dec 2011

The Valuation Of User-Generated Content: A Structural, Stylistic And Semantic Analysis Of Online Reviews, Noi Sian Koh

Dissertations and Theses Collection (Open Access)

The ability and ease for users to create and publish content has provided vast amount of online product reviews. However, the amount of data is overwhelmingly large and unstructured, making information difficult to quantify. This creates challenge in understanding how online reviews affect consumers’ purchase decisions. In my dissertation, I explore the structural, stylistic and semantic content of online reviews. Firstly, I present a measurement that quantifies sentiments with respect to a multi-point scale and conduct a systematic study on the impact of online reviews on product sales. Using the sentiment metrics generated, I estimate the weight that customers place …


Dynamic Server Allocation At Parallel Queues, Susan E. Martonosi Dec 2011

Dynamic Server Allocation At Parallel Queues, Susan E. Martonosi

All HMC Faculty Publications and Research

We explore whether dynamically reassigning servers to parallel queues in response to queue imbalances can reduce average waiting time in those queues. We use approximate dynamic programming methods to determine when servers should be switched, and we compare the performance of such dynamic allocations to that of a pre-scheduled deterministic allocation. Testing our method on both synthetic data and data from airport security checkpoints at Boston Logan International Airport, we find that in situations where the uncertainty in customer arrival rates is significant, dynamically reallocating servers can substantially reduce waiting time. Moreover, we find that intuitive switching strategies that are …


From Double Lie Groupoids To Local Lie 2-Groupoids, Rajan Amit Mehta, Xiang Tang Dec 2011

From Double Lie Groupoids To Local Lie 2-Groupoids, Rajan Amit Mehta, Xiang Tang

Mathematics Sciences: Faculty Publications

We apply the bar construction to the nerve of a double Lie groupoid to obtain a local Lie 2-groupoid. As an application, we recover Haefliger's fundamental groupoid from the fundamental double groupoid of a Lie groupoid. In the case of a symplectic double groupoid, we study the induced closed 2-form on the associated local Lie 2-groupoid, which leads us to propose a definition of a symplectic 2-groupoid.


An Extension Of The Rishon Model, Paul Finkler Dec 2011

An Extension Of The Rishon Model, Paul Finkler

Paul Finkler Papers

We present an extension of the Rishon Model of Harari, et. al. [1] [2] [3] In that model, the first generation leptons and quarks are each made from three rishons of two varieties, T and V as follows: ve = V V V , e+ = T T T , d = T V V , and u = T T V . In addition to the original rishons and their anti-rishons T and V , we introduce the dark rishon X and its anti-rishon X; all have spin 1/2.

An exciting possibility that emerges from this idea …


Quantum Many-Body Calculation Of Mixed-Parity Pairing In The Sr2ruo4 Superconductor Induced By Spin-Orbit Coupling, J. J. Deisz, Tim Kidd Dec 2011

Quantum Many-Body Calculation Of Mixed-Parity Pairing In The Sr2ruo4 Superconductor Induced By Spin-Orbit Coupling, J. J. Deisz, Tim Kidd

Faculty Publications

The unusual superconducting state in Sr2RuO4 has long been viewed as being analogous to a superfluid state in liquid 3He. Nevertheless, calculations based on this odd-parity state are presently unable to completely reconcile the properties of Sr2RuO4. Using a self-consistent quantum many-body scheme that employs realistic parameters, we are able to model several signature properties of the normal and superconducting states of Sr2RuO4. We find that the dominant component of the model superconducting state is of even parity and closely related to superconducting state for the high-Tc …


Localization Of Objects Using Cross-Correlation Of Shadow Fading Noise And Copulas, Mohammed Rana Basheer, Sarangapani Jagannathan Dec 2011

Localization Of Objects Using Cross-Correlation Of Shadow Fading Noise And Copulas, Mohammed Rana Basheer, Sarangapani Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

While fading, in general, is detrimental to accurately localizing a target, fading correlation between adjacent receivers may be exploited to improve localization accuracy. Therefore, this paper presents a novel wireless localization scheme that employs a combination of cross-correlation between shadow fading noise and copula technique to recursively estimate the location of a transmitter. a stochastic filter that models multipath fading as an Ornstein-Uhlenbeck process followed by a Generalized Auto Regressive Conditional Heteroskedasticity (GARCH) filtering is proposed to extract shadow fading residuals from measured RSSI values. Subsequently, Student-t Copula function is used to create the log likelihood function, which acts as …


Personalized Searching For Web Service Using User Interests, Rong Hu, Wanchun Dou, Xiaoqing Frank Liu, Jianxun Liu Dec 2011

Personalized Searching For Web Service Using User Interests, Rong Hu, Wanchun Dou, Xiaoqing Frank Liu, Jianxun Liu

Computer Science Faculty Research & Creative Works

Users usually have different prospective even they input a same keyword to search Web services. It is a challenge to personalize web service search engine as more and more keyword-like Web services becoming available on Internet. User interest plays an important role in personalizing search result. Therefore, through interest extraction, Web service search engine is personalized. at last, an experiment is presented to demonstrate the feasibility of the method. © 2011 IEEE.


Exploring Caching For Efficient Collection Operations, Swetha Surapaneni, Venkata Krishna Suhas Nerella, Sanjay K. Madria, Thomas Weigert Dec 2011

Exploring Caching For Efficient Collection Operations, Swetha Surapaneni, Venkata Krishna Suhas Nerella, Sanjay K. Madria, Thomas Weigert

Computer Science Faculty Research & Creative Works

Many useful programs operate on collection types. Extensive libraries are available in many programming languages, such as the C++ Standard Template Library, which make programming with collections convenient. Extending programming languages to provide collection queries as first class constructs in the language would not only allow programmers to write queries explicitly in their programs but it would also allow compilers to leverage the wealth of experience available from the database domain to optimize such queries. This paper describes an approach to reducing the run time of programs involving explicit collection queries by leveraging a cache to store previously computed results. …


Middleware For Supporting Content Sharing In Dynamic Networks, Mohan Kumar, Sharma Chakravarthy, Sanjay Kumar Madria, Mark Linderman, Waseem Naqvi Dec 2011

Middleware For Supporting Content Sharing In Dynamic Networks, Mohan Kumar, Sharma Chakravarthy, Sanjay Kumar Madria, Mark Linderman, Waseem Naqvi

Computer Science Faculty Research & Creative Works

This paper proposes a middleware architecture to enable seamless content sharing in highly dynamic networks, such as those involving a number of aerial unmanned autonomous vehicles (UAVs), which are characterized by constantly changing connectivity and network topology. the proposed middleware maintains up-to-date network status as well as metadata information about data objects in the network nodes, masking the content sharing applications from the network dynamics and faults. Mechanisms for node discovery, message passing, and network management are developed. a strategy is also proposed for efficient replication to ensure availability of data in highly mobile environments. the middleware includes a message …


Object Recognition Based On Shape And Function, Akihiro Eguchi Dec 2011

Object Recognition Based On Shape And Function, Akihiro Eguchi

Computer Science and Computer Engineering Undergraduate Honors Theses

This thesis explores a new approach to computational object recognition by borrowing an idea from child language acquisition studies in developmental psychology. Whereas previous image recognition research used shape to recognize and label a target object, the model proposed in this thesis also uses the function of the object resulting in a more accurate recognition. This thesis makes use of new gaming technology, Microsoft’s Kinect, in implementing the proposed new object recognition model. A demonstration of the model developed in this project properly infers different names for similarly shaped objects and the same name for differently shaped objects.


Energy-Based Analysis Of Utility Scale Hybrid Power Systems, Kwame Agyenim-Boateng Dec 2011

Energy-Based Analysis Of Utility Scale Hybrid Power Systems, Kwame Agyenim-Boateng

UNLV Theses, Dissertations, Professional Papers, and Capstones

The promise of large-scale use of renewables such as wind and solar for supplying electrical power is tempered by the sources' transient behavior and the impact this would have on the operation of the grid. Among the methods cited for addressing some of those concerns are exploring the complementary nature of solar and wind power generation, and through the use of supplemental energy storage. While the technology for the latter has not been proven to be economical on a large scale at the present time, some assessments of what magnitude is required can be made. An energy-based analysis of utility …


Computing Inconsistency Measure Based On Paraconsistent Semantics, Pascal Hitzler, Yue Ma, Guilin Qi Dec 2011

Computing Inconsistency Measure Based On Paraconsistent Semantics, Pascal Hitzler, Yue Ma, Guilin Qi

Computer Science and Engineering Faculty Publications

Measuring inconsistency in knowledge bases has been recognized as an important problem in several research areas. Many methods have been proposed to solve this problem and a main class of them is based on some kind of paraconsistent semantics. However, existing methods suffer from two limitations: (i) they are mostly restricted to propositional knowledge bases; (ii) very few of them discuss computational aspects of computing inconsistency measures. In this article, we try to solve these two limitations by exploring algorithms for computing an inconsistency measure of first-order knowledge bases. After introducing a four-valued semantics for first-order logic, we define an …


Overview Of Contrast Data Mining As A Field And Preview Of An Upcoming Book, Guozhu Dong, James Bailey Dec 2011

Overview Of Contrast Data Mining As A Field And Preview Of An Upcoming Book, Guozhu Dong, James Bailey

Kno.e.sis Publications

This report provides an overview of the field of contrast data mining and its applications, and offers a preview of an upcoming book on the topic. The importance of contrasting is discussed and a brief survey is given covering the following topics: general definitions and terminology for contrast patterns, representative contrast pattern mining algorithms, applications of contrast mining for fundamental data mining tasks such as classification and clustering, applications of contrast mining in bioinformatics, medicine, blog analysis, image analysis and subgroup mining, results on contrast based dataset similarity measure, and on analyzing item interaction in contrast patterns, and open research …


Analysis Of Volatile Organic Compounds In Virgin Coconut Oil And Their Sensory Attibutes, Fabian M. Dayrit, Jaclyn Elizabeth R. Santos, Bianca J. Villarino, Anthony R. Zosa Dec 2011

Analysis Of Volatile Organic Compounds In Virgin Coconut Oil And Their Sensory Attibutes, Fabian M. Dayrit, Jaclyn Elizabeth R. Santos, Bianca J. Villarino, Anthony R. Zosa

Chemistry Faculty Publications

The volatile compounds in the headspace of twenty-four commercial virgin coconut oil (VCO) samples prepared by different methods (i.e. expeller, centrifugation, and fermentation with and without heat) were analyzed by solid phase microextraction-gas chromatography mass spectrometry (SPME-GCMS). The following volatile organic compounds (VOCs) were identified: ethyl acetate, acetic acid, 2-pentanone, hexanal, n-octane, 2-heptanone, limonene, nonanal, octanoic acid, ethyl octanoate, δ-octalactone, ethyl decanoate, δ-decalactone, and dodecanoic acid. Fermentation-produced samples were found to have higher levels of acetic acid and free fatty acids in the headspace compared to VCO produced using the centrifuge and expeller methods. Descriptive sensory analysis of the VCO …