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2009

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Articles 7021 - 7050 of 7616

Full-Text Articles in Physical Sciences and Mathematics

Complex Symmetric Partial Isometries, Stephan Ramon Garcia, Warren R. Wogen Jan 2009

Complex Symmetric Partial Isometries, Stephan Ramon Garcia, Warren R. Wogen

Pomona Faculty Publications and Research

An operator $T \in B(\h)$ is complex symmetric if there exists a conjugate-linear, isometric involution $C:\h\to\h$ so that $T = CT^*C$. We provide a concrete description of all complex symmetric partial isometries. In particular, we prove that any partial isometry on a Hilbert space of dimension $\leq 4$ is complex symmetric.

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Every Graph Has An Embedding In S³ Containing No Non-Hyperbolic Knot, Erica Flapan, Hugh Howards Jan 2009

Every Graph Has An Embedding In S³ Containing No Non-Hyperbolic Knot, Erica Flapan, Hugh Howards

Pomona Faculty Publications and Research

In contrast with knots, whose properties depend only on their extrinsic topology in S³ , there is a rich interplay between the intrinsic structure of a graph and the extrinsic topology of all embeddings of the graph in S³ . For example, it was shown by Conway and Gordon that every embedding of the complete graph K_7 in S³ contains a non-trivial knot. Later it was shown that for every m ∈ N there is a complete graph K_n such that every embedding of K_n in S³ contains a knot Q whose minimal crossing number is at least m. …

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Review: Graded Structure And Hopf Structures In Parabosonic Algebra. An Alternative Approach To Bosonisation, Gizem Karaali Jan 2009

Review: Graded Structure And Hopf Structures In Parabosonic Algebra. An Alternative Approach To Bosonisation, Gizem Karaali

Pomona Faculty Publications and Research

No abstract provided.

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Review: Solutions For The Constant Quantum Yang-Baxter Equation From Lie (Super)Algebras, Gizem Karaali Jan 2009

Review: Solutions For The Constant Quantum Yang-Baxter Equation From Lie (Super)Algebras, Gizem Karaali

Pomona Faculty Publications and Research

No abstract provided.

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Review: Set-Theoretic Solutions Of The Yang-Baxter Equation, Graphs And Computations, Gizem Karaali Jan 2009

Review: Set-Theoretic Solutions Of The Yang-Baxter Equation, Graphs And Computations, Gizem Karaali

Pomona Faculty Publications and Research

No abstract provided.

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The Once And Future Forest Service: Land-Management Policies And Politics In Contemporary America, Char Miller Jan 2009

The Once And Future Forest Service: Land-Management Policies And Politics In Contemporary America, Char Miller

Pomona Faculty Publications and Research

The news from the Far North is not good. In the spring of 2007, University of Alberta scientists reported that portions of the Canadian tundra were transforming into new forests of spruce and shrubs much more rapidly than once was imaginable. "The conventional thinking on treeline dynamics has been that advances are very slow because conditions are so harsh at these high latitudes and altitudes," reported Dr. Ryan Danby, a member of the UA research team. "But what our data indicate is that there was an upslope surge of trees in response to warmer temperatures. It's like [the forest] waited …

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A Different Pencil Too Good To Be Ignored? A First Look At Wolfram|Alpha, Gizem Karaali, Bruce Yoshiwara Jan 2009

A Different Pencil Too Good To Be Ignored? A First Look At Wolfram|Alpha, Gizem Karaali, Bruce Yoshiwara

Pomona Faculty Publications and Research

So you came across several news pieces about Wolfram|Alpha and you’re wondering what all the fuss is about. Let’s start with the basics.

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Development Of A Novel Humidity Sensor Based On A Polymer Silver Nanoparticle Composite, Aoife Power, John Cassidy, Tony Betts Jan 2009

Development Of A Novel Humidity Sensor Based On A Polymer Silver Nanoparticle Composite, Aoife Power, John Cassidy, Tony Betts

Conference Papers

Humidity sensing is of particular concern for many industrial applications. Humidity sensors have typically been based on a reversible interaction between a polymer and water vapour. There is work published on gas sensors based on polymer gold nanoparticle composites, where the conductivity of the composite decreases on interaction with the gas. This happens because the swelling of the polymer which increases the electron hopping distance between the gold nanoparticles. The device in this work is a poly vinyl alcohol silver nanoparticle composite cast on an interdigital electrode array. On application of a dc bias, a current develops which is proportional …

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Folate-Cyclodextrin Conjugate For Targeted Chemotherapy, Zlata Tofzikovskaya, Orla L. Howe, Mary Mcnamara, Christine O'Connor Jan 2009

Folate-Cyclodextrin Conjugate For Targeted Chemotherapy, Zlata Tofzikovskaya, Orla L. Howe, Mary Mcnamara, Christine O'Connor

Conference Papers

A general disadvantage of chemotherapy is that the drugs cannot discriminate between fast-growing cancer cells and normal healthy cells which causes many side-effects such as hair loss. An ideal solution to current methods of chemotherapy would be the development of a carrier for an anticancer drug which would be able to transport the drug and therefore target only cancer cells and release the drug molecules inside the cells. In this work folic acid (FA) is attached to an aminoalkane derivative of b-cyclodextrin (CDEn) with a view to developing novel drug delivery systems for therapeutic purposes. Cytotoxisity of folate-conjugate (CDEnFA) is …

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Ophiolite-Hosted Copper And Gold Deposits Of Southeastern Turkey: Formation And Relationship With Seafloor Hydrothermal Processes, Ömer Tezcan Akinci Jan 2009

Ophiolite-Hosted Copper And Gold Deposits Of Southeastern Turkey: Formation And Relationship With Seafloor Hydrothermal Processes, Ömer Tezcan Akinci

Turkish Journal of Earth Sciences

The paper documents evidence about the physical and chemical controls on the behaviour of Au and Cu sulphide deposits in fossil seafloor hydrothermal systems of SE Turkey. Observations from actively forming sulphides at mid-ocean ridges (MOR) and in back-arc environments are compared briefly with ancient analogues of gold and pyritic copper deposits such as Kisecik, Ergani and Siirt-Madenköy, formed at mid-oceanic ridges, or possibly at seamounts and back-arc settings. Many ophiolite-hosted Au- and Cu-deposits, of various sizes, are known to exist along the Bitlis-Zagros Suture Zone (BZS), the boundary between Anatolian and Arabian plates in SE Turkey. These deposits are …

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Growth And Microindentation Analysis Of Pure And Doped Sb_2se_3 Crystals, K. A. Chandrasekharan, A. G. Kunjomana Jan 2009

Growth And Microindentation Analysis Of Pure And Doped Sb_2se_3 Crystals, K. A. Chandrasekharan, A. G. Kunjomana

Turkish Journal of Physics

Pure and doped antimony selenide (Sb_2Se_3, Sb_2Se_{2.8}Te_{0.2}, and Sb_2Se_{2.6}Te_{0.4}) crystals have been grown from melt by the Bridgman Stockbarger method. X-ray powder diffraction analysis was carried out to determine the lattice parameters of the grown samples. The morphology of cleavage planes was observed using SEM. Energy dispersive analysis by X-rays (EDAX) was done to find out the chemical composition of the grown samples. Correlation of microhardness with other mechanical characteristics such as toughness, brittleness, and yield strength, has been investigated. The effects of Te doping on the mechanical behaviour and energy gap were also studied on the cleavage faces.

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Oil Platforms And Red Snapper Movement And Behavior, Michael Mcdonough Jan 2009

Oil Platforms And Red Snapper Movement And Behavior, Michael Mcdonough

LSU Master's Theses

Understanding the behavior, including movement, of red snapper (Lutjanus campechanus), around and among the many oil and gas platforms in the northern Gulf of Mexico (GOM) is crucial to the management of this important commercial and recreational species. What role oil and gas production platforms play in the attraction vs. production continuum for red snapper is unknown, but it is certain these large structures have a role at some life history stage. We used the VRAP acoustic telemetry system to track red snapper around two platforms in the GOM in 2005 and 2006. Fish detections per hour generally decreased over …

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Mortality Of Diamondback Terrapins In Blue Crab Traps: Population Changes And Conservation In Southeastern Virginia, Megan Ann Rook Jan 2009

Mortality Of Diamondback Terrapins In Blue Crab Traps: Population Changes And Conservation In Southeastern Virginia, Megan Ann Rook

Dissertations, Theses, and Masters Projects

No abstract provided.

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The Synthesis And Spectroscopic Study Of A Spirooxazine-Functionalized Poly(Phenylenevinylene), Jordan Thomas Walk Jan 2009

The Synthesis And Spectroscopic Study Of A Spirooxazine-Functionalized Poly(Phenylenevinylene), Jordan Thomas Walk

Dissertations, Theses, and Masters Projects

No abstract provided.

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Cyclization Reactions Catalyzed By Bi(Iii) Compounds, Jia Liu Jan 2009

Cyclization Reactions Catalyzed By Bi(Iii) Compounds, Jia Liu

Dissertations, Theses, and Masters Projects

No abstract provided.

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Counting Links In Complete Graphs, Thomas Fleming, Blake Mellor Jan 2009

Counting Links In Complete Graphs, Thomas Fleming, Blake Mellor

Mathematics, Statistics and Data Science Faculty Works

We find the minimal number of non-trivial links in an embedding of any complete kk-partite graph on 7 vertices (including K7, which has at least 21 non-trivial links). We give either exact values or upper and lower bounds for the minimal number of non-trivial links for all complete kk-partite graphs on 8 vertices. We also look at larger complete bipartite graphs, and state a conjecture relating minimal linking embeddings with minimal book embeddings.

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Ecosystem Modeling Of College Drinking: Parameter Estimation And Comparing Models To Data, Azmy S. Ackleh, Ben G. Fitzpatrick, Richard Scribner, Neal Simonsen, Jeremy J. Thibodeaux Jan 2009

Ecosystem Modeling Of College Drinking: Parameter Estimation And Comparing Models To Data, Azmy S. Ackleh, Ben G. Fitzpatrick, Richard Scribner, Neal Simonsen, Jeremy J. Thibodeaux

Mathematics, Statistics and Data Science Faculty Works

Recently we developed a model composed of five impulsive differential equations that describes the changes in drinking patterns (that persist at epidemic level) amongst college students. Many of the model parameters cannot be measured directly from data; thus, an inverse problem approach, which chooses the set of parameters that results in the “best” model to data fit, is crucial for using this model as a predictive tool. The purpose of this paper is to present the procedure and results of an unconventional approach to parameter estimation that we developed after more common approaches were unsuccessful for our specific problem. The …

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In-Situ Ambient Quantification Of Monoterpenes, Sesquiterpenes And Related Oxygenated Compounds During Bearpex 2007: Implications For Gas-And Particle-Phase Chemistry, Nicole Bouvier-Brown Jan 2009

In-Situ Ambient Quantification Of Monoterpenes, Sesquiterpenes And Related Oxygenated Compounds During Bearpex 2007: Implications For Gas-And Particle-Phase Chemistry, Nicole Bouvier-Brown

Chemistry and Biochemistry Faculty Works

We quantified ambient mixing ratios of 9 monoterpenes, 6 sesquiterpenes, methyl chavicol, the oxygenated terpene linalool, and nopinone using an in-situ gas chromatograph with a quadrupole mass spectrometer (GC-MS). These measurements were a part of the 2007 Biosphere Effects on AeRosols and Photochemistry EXperiment (BEARPEX) at Blodgett Forest, a ponderosa pine forest in the Sierra Nevada Mountains of California. To our knowledge, these observations represent the first direct in-situ ambient quantification of the sesquiterpenes α-bergamotene, longifolene, α-farnesene, and β-farnesene. From average diurnal mixing ratio profiles, we show that α-farnesene emissions are dependent mainly on temperature whereas α-bergamotene and β-farnesene emissions …

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Methyl Chavicol: Characterization Of Its Biogenic Emission Rate, Abundance, And Oxidation Products In The Atmosphere, Nicole Bouvier-Brown Jan 2009

Methyl Chavicol: Characterization Of Its Biogenic Emission Rate, Abundance, And Oxidation Products In The Atmosphere, Nicole Bouvier-Brown

Chemistry and Biochemistry Faculty Works

We report measurements of ambient atmospheric mixing ratios for methyl chavicol and determine its biogenic emission rate. Methyl chavicol, a biogenic oxygenated aromatic compound, is abundant within and above Blodgett Forest, a ponderosa pine forest in the Sierra Nevada Mountains of California. Methyl chavicol was detected simultaneously by three in-situ instruments – a gas chromatograph with mass spectrometer detector (GC-MS), a proton transfer reaction mass spectrometer (PTR-MS), and a thermal desorption aerosol GC-MS (TAG) – and found to be abundant within and above Blodgett Forest. Methyl chavicol atmospheric mixing ratios are strongly correlated with 2-methyl-3-buten-2-ol (MBO), a light- and temperature-dependent …

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Suppression Of South Asian Summer Monsoon Precipitation In The 21st Century, Moetasim Ashfaq, Ying Shi, Wen-Wen Tung, Robert J. Trapp, Xueijie Gao, Jeremy S. Pal, Noah S. Diffenbaugh Jan 2009

Suppression Of South Asian Summer Monsoon Precipitation In The 21st Century, Moetasim Ashfaq, Ying Shi, Wen-Wen Tung, Robert J. Trapp, Xueijie Gao, Jeremy S. Pal, Noah S. Diffenbaugh

Civil and Environmental Engineering Faculty Works

We used a high-resolution nested climate modeling system to investigate the response of South Asian summer monsoon dynamics to anthropogenic increases in greenhouse gas concentrations. The simulated dynamical features of the summer monsoon compared well with reanalysis data and observations. Further, we found that enhanced greenhouse forcing resulted in overall suppression of summer precipitation, a delay in monsoon onset, and an increase in the occurrence of monsoon break periods. Weakening of the large-scale monsoon flow and suppression of the dominant intraseasonal oscillatory modes were instrumental in the overall weakening of the South Asian summer monsoon. Such changes in monsoon dynamics …

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On The Estimation Of Averages Over Infinite Intervals With An Application To Average Persistence In Population Models, Sean F. Ellermeyer Jan 2009

On The Estimation Of Averages Over Infinite Intervals With An Application To Average Persistence In Population Models, Sean F. Ellermeyer

Faculty Articles

We establish a general result for estimating the upper average of a continuous and bounded function over an infinite interval. As an application, we show that a previously studied model of microbial growth in a chemostat with time–varying nutrient input admits solutions (populations) that exhibit weak persistence but not weak average persistence.

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A Dynamic Insertion Approach For Multi-Dimensional Data Using Index Structures, Yong Shi Jan 2009

A Dynamic Insertion Approach For Multi-Dimensional Data Using Index Structures, Yong Shi

Faculty Articles

Nowadays large volumes of data with high dimensionality are being generated in many fields. Most existing indexing techniques degrade rapidly when dimensionality goes higher. A large amount of data sets are time related, and the existence of the obsolete data in the data sets may seriously degrade the data processing. In our previous work[7], we proposed ClusterTree+, a new indexing approach representing clusters generated by any existing clustering approach. It is a hierarchy of clusters and subclusters which incorporates the cluster representation into the index structure to achieve effective and efficient retrieval. It also has features from the …

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Influence Of Irradiance And Iron On The Growth Of Colonial Phaeocystic Antarctica: Implications For Seasonal Bloom Dynamics In The Ross Sea, Antarctica, Nathan S. Garcia, Peter N. Sedwick, Giacomo R. Ditullio Jan 2009

Influence Of Irradiance And Iron On The Growth Of Colonial Phaeocystic Antarctica: Implications For Seasonal Bloom Dynamics In The Ross Sea, Antarctica, Nathan S. Garcia, Peter N. Sedwick, Giacomo R. Ditullio

OES Faculty Publications

Laboratory culture experiments were used to investigate the growth rate of colonial Phaeocystis anarctica as a function of irradiance and dissolved iron concentration. The experiments were conducted with a P. antarctica strain isolated from the southern Ross Sea, Antarctica, and made use of natural, low-iron (P. antarctica attained an average maximum cell-specific growth rate of 0.37 d-1at an irradiance of 68 μE m-2s-1, above which growth rates decreased to 0.27 d-1 at an irradiance of 314 μE m-2s-1. The dependence of growth rate on ambient dissolved iron concentration was …

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Geobiology: Evidence For Early Life On Earth And The Search For Life On Other Planets, Sherry L. Cady, Nora Noffke Jan 2009

Geobiology: Evidence For Early Life On Earth And The Search For Life On Other Planets, Sherry L. Cady, Nora Noffke

OES Faculty Publications

Extensive research efforts in the subdisciplinary field of geobiology have focused on the interactions between Earth and life through time. As a consequence, gaps in our knowledge of Earth’s history are closing, and the search for life beyond Earth is expanding. A few examples of geobiology studies designed to advance our understanding of life on early Earth and to improve the chances of finding life on other planets are provided to highlight recent developments and research areas that are on the verge of new discoveries.

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Peptide Hydrolysis And The Uptake Of Dipeptides By Phytoplankton, Margaret R. Mulholland, Cindy Lee Jan 2009

Peptide Hydrolysis And The Uptake Of Dipeptides By Phytoplankton, Margaret R. Mulholland, Cindy Lee

OES Faculty Publications

Rates of peptide hydrolysis (using the fluorescent substrate, lucifer yellow anhydride-labeled tetra-alanine) and dipeptide uptake (using dually labeled, 15N and 13C, dialanine) were measured in phytoplankton cultures and in natural populations during algal blooms dominated by one or two taxa. During most sampling events, both peptide hydrolysis and dipeptide uptake were greatest in the size fraction containing the dominant phytoplankter, suggesting that phytoplankton contribute substantially to or may even dominate observed extracellular peptide hydrolysis and dipeptide uptake in the environment. These are the first data suggesting that dipeptides may be taken up directly by phytoplankton and this may …

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The Effects Of Climate Change On Biodiversity: Pressing Issues And Research Priorities, Friedhelm Krupp, Lytton J. Musselman, Mohammed M.A. Kotb, Ilka Weidig Jan 2009

The Effects Of Climate Change On Biodiversity: Pressing Issues And Research Priorities, Friedhelm Krupp, Lytton J. Musselman, Mohammed M.A. Kotb, Ilka Weidig

Biological Sciences Faculty Publications

No abstract provided.

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The Epidemiological Status Of Pav1, And The Effects Of Infection On Caribbean Spiny Lobster (Panulirus Argus) Condition, Olfaction, And Predation Risk, Donald C. Behringer, Mark J. Butler Iv, Jeffrey D. Shields Jan 2009

The Epidemiological Status Of Pav1, And The Effects Of Infection On Caribbean Spiny Lobster (Panulirus Argus) Condition, Olfaction, And Predation Risk, Donald C. Behringer, Mark J. Butler Iv, Jeffrey D. Shields

Biological Sciences Faculty Publications

No abstract provided.

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Patterns Of Spiny Lobster (Panulirus Argus) Postlarval Recruitment In The Carribbean: A Crtr Project, Mark J. Butler Iv, Angela M. Mojica, Eloy Sosa-Cordero, Marines Millet, Paul Sanchez-Navarro, Miguel A. Maldonado, Juan Posada, Bladimir Rodriguez, Carlos M. Rivas, Adrian Oviedo, Marcio Arrone, Martha Prada, Nick Bach, Nilda Jimenez, Maria Del Carmen Garcia-Rivas, Kirah Forman, Donald C. Behringer Jr., Thomas Matthews, Claire Paris, Robert Cowen Jan 2009

Patterns Of Spiny Lobster (Panulirus Argus) Postlarval Recruitment In The Carribbean: A Crtr Project, Mark J. Butler Iv, Angela M. Mojica, Eloy Sosa-Cordero, Marines Millet, Paul Sanchez-Navarro, Miguel A. Maldonado, Juan Posada, Bladimir Rodriguez, Carlos M. Rivas, Adrian Oviedo, Marcio Arrone, Martha Prada, Nick Bach, Nilda Jimenez, Maria Del Carmen Garcia-Rivas, Kirah Forman, Donald C. Behringer Jr., Thomas Matthews, Claire Paris, Robert Cowen

Biological Sciences Faculty Publications

As part of the Coral Reef Targeted Research (CRTR) Program, a partnership between the Global Environment Facility and the World Bank, our research team examined the recruitment patterns of Caribbean spiny lobster (Panulirus argus) postlarvae among regions in the Caribbean, with a particular focus on Mesoamerica. Our goal was to collect comparable information on postlarval supply among regions and to provide data to test predictions of connectivity generated from a coupled biophysical oceanographic model of lobster larval dispersal. Here we present the results of the postlarval recruitment monitoring program. We monitored the catch of postlarvae on Witham-style collectors …

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Autonomous Abstraction Of Policies Based On Policy Homomorphism, Srividhya Rajendran Jan 2009

Autonomous Abstraction Of Policies Based On Policy Homomorphism, Srividhya Rajendran

Computer Science and Engineering Dissertations

A life long learning agent performing in a complex and dynamic environment needs the ability to learn increasingly complex tasks over time. These agents over their lifetime have to learn new tasks, adapt the policies of already learned tasks and extract and reuse the knowledge gained to learn new, more complex tasks. To do this, they need methods that allow them to autonomously extract knowledge from the already learned policy instances and reuse the knowledge gained to learn related tasks in novel environments.This dissertation presents a novel approach that enables an agent to autonomously abstract reusable skills and concepts using …

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Unusual Anatomy Of The Ectoparasitic Muricid Vitularia Salebrosa (King And Broderip, 1832) (Neogastropoda: Muricidae) From The Pacific Coast Of Panama, Luiz R. L. Simone, Gregory S. Herbert, Didier Merle Jan 2009

Unusual Anatomy Of The Ectoparasitic Muricid Vitularia Salebrosa (King And Broderip, 1832) (Neogastropoda: Muricidae) From The Pacific Coast Of Panama, Luiz R. L. Simone, Gregory S. Herbert, Didier Merle

School of Geosciences Faculty and Staff Publications

The morphology and anatomy of Vitularia salebrosa, a muricid ectoparasitic on other mollusks, are investigated based on study of specimens from western Panama. Distinctive characters of this species include the small size of the buccal mass and radular apparatus, simplification of the odontophore muscles and diminished lateral teeth of the radula; an elongated, narrow proboscis; narrow digestive tract and a differentiable glandular region at the beginning of the posterior esophagus. These traits are consistent with adaptive specialization for an ectoparasitic life history

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