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UniversityMangilao Village, Guam

Research output, citation impact, and the most-cited recent papers from University of Guam (Guam). Aggregated across the NobleBlocks index of 300M+ scholarly works.

Total works
4.1K
Citations
106.8K
h-index
133
i10-index
1.9K
Also known as
Unibetsedåt GuåhanUniversity of Guam

Top-cited papers from University of Guam

Seaweed Ecology and Physiology
Catriona L. Hurd, Paul J. Harrison, Kai Bischof, Christopher S. Lobban
2014· Cambridge University Press eBooks1.6Kdoi:10.1017/cbo9781139192637

In coastal seas, from the tropics to the poles, seaweeds supply the energy required to support diverse coastal marine life and provide habitat for invertebrates and fish. Retaining the highly successful approach and structure of the first edition, this is a synthesis of the role of seaweeds in underpinning the functioning of coastal ecosystems worldwide. It has been fully updated to cover the major developments of the past twenty years, including current research on the endosymbiotic origin of algae, molecular biology including 'omics', chemical ecology, invasive seaweeds, photobiology and stress physiology. In addition to exploring the processes by which seaweeds, as individuals and communities, interact with their biotic and abiotic environment, the book presents exciting new research on how seaweeds respond to local and global environmental change. It remains an invaluable resource for students and provides an entry into the scientific literature of a wide range of topics.

Seaweed Ecology and Physiology
Christopher S. Lobban, Paul J. Harrison
1994· Cambridge University Press eBooks790doi:10.1017/cbo9780511626210

A rewritten and re-organised edition of The Physiological Ecology of Seaweeds (1985). Seaweed Ecology and Physiology surveys the broad literature, but it is not merely an update of the earlier book. This book contains an introductory chapter reviewing seaweed morphology, cytology, and life histories. The chapter on community level ecology now includes six guest essays by senior algal ecologists which conveys the excitement of phycological research. The treatment of tropical seaweeds had been expanded, reflecting the growing literature from tropical regions, and the authors' experiences in the tropics. The final chapter on mariculture is much larger, and includes a case study on how principles of physiological ecology were applied in developing the carrageenan industry. Finally there is an appendix summarising the taxonomic position and nomenclature of the species mentioned in the book.

Reproduction and recruitment of corals: comparisons among the Caribbean, the Tropical Pacific, and the Red Sea
RH Richmond, Cynthia Hunter
1990· Marine Ecology Progress Series570doi:10.3354/meps060185

Detailed reproductive data are now available for 210 of the ca 600 identified scleractinian reef coral species. The majonty (131 species) are hermaphroditic broadcast spawners, although hermaphroditic brooders (1 1 species), gonochoristic broadcasters (37 species), and gonochoristic brooders (7 species) have also been reported. Characteristics of sexuality and mode of reproduction are generally conservative within species, genera, and even families, although some exceptions occur. Variation in timing or mode of reproduction in allopatric populations may represent adaptations to local environmental conditions or indicate problems in the taxonomy of some groups. Synchronous spawning of numerous species occurs on the Great Barrier Reef, while asynchrony among and withln species has been observed in the Red Sea, Caribbean, Central Pacific, Hawall, and southern Japan. Sexual reproduct~on is the primary means for successful recruitment for some coral populations, while asexual processes may be the dominant or sole means of recruitment for these same species at the limits of their ranges. Recruitment success of different reproductive strategies may vary within and between localities, and is mediated by both biotic (predation, competition) and abiotic (environmental variability, disturbance) factors. Data on reproductive patterns and recruitment success may be applied to coral reef management practices.

Assessing the complex sponge microbiota: core, variable and species-specific bacterial communities in marine sponges
Susanne Schmitt, Peter Tsai, James J. Bell, Jane Fromont +4 more
2011· The ISME Journal554doi:10.1038/ismej.2011.116

Marine sponges are well known for their associations with highly diverse, yet very specific and often highly similar microbiota. The aim of this study was to identify potential bacterial sub-populations in relation to sponge phylogeny and sampling sites and to define the core bacterial community. 16S ribosomal RNA gene amplicon pyrosequencing was applied to 32 sponge species from eight locations around the world's oceans, thereby generating 2567 operational taxonomic units (OTUs at the 97% sequence similarity level) in total and up to 364 different OTUs per sponge species. The taxonomic richness detected in this study comprised 25 bacterial phyla with Proteobacteria, Chloroflexi and Poribacteria being most diverse in sponges. Among these phyla were nine candidate phyla, six of them found for the first time in sponges. Similarity comparison of bacterial communities revealed no correlation with host phylogeny but a tropical sub-population in that tropical sponges have more similar bacterial communities to each other than to subtropical sponges. A minimal core bacterial community consisting of very few OTUs (97%, 95% and 90%) was found. These microbes have a global distribution and are probably acquired via environmental transmission. In contrast, a large species-specific bacterial community was detected, which is represented by OTUs present in only a single sponge species. The species-specific bacterial community is probably mainly vertically transmitted. It is proposed that different sponges contain different bacterial species, however, these bacteria are still closely related to each other explaining the observed similarity of bacterial communities in sponges in this and previous studies. This global analysis represents the most comprehensive study of bacterial symbionts in sponges to date and provides novel insights into the complex structure of these unique associations.

Local-scale projections of coral reef futures and implications of the Paris Agreement
Ruben van Hooidonk, Jeffrey Maynard, Jerker Tamelander, Jamison M. Gove +4 more
2016· Scientific Reports458doi:10.1038/srep39666

Abstract Increasingly frequent severe coral bleaching is among the greatest threats to coral reefs posed by climate change. Global climate models (GCMs) project great spatial variation in the timing of annual severe bleaching (ASB) conditions; a point at which reefs are certain to change and recovery will be limited. However, previous model-resolution projections (~1 × 1°) are too coarse to inform conservation planning. To meet the need for higher-resolution projections, we generated statistically downscaled projections (4-km resolution) for all coral reefs; these projections reveal high local-scale variation in ASB. Timing of ASB varies >10 years in 71 of the 87 countries and territories with > 500 km 2 of reef area. Emissions scenario RCP4.5 represents lower emissions mid-century than will eventuate if pledges made following the 2015 Paris Climate Change Conference (COP21) become reality. These pledges do little to provide reefs with more time to adapt and acclimate prior to severe bleaching conditions occurring annually. RCP4.5 adds 11 years to the global average ASB timing when compared to RCP8.5; however, >75% of reefs still experience ASB before 2070 under RCP4.5. Coral reef futures clearly vary greatly among and within countries, indicating the projections warrant consideration in most reef areas during conservation and management planning.

Revisiting metazoan phylogeny with genomic sampling of all phyla
Christopher Laumer, Rosa Fernández, Sarah Lemer, David J. Combosch +4 more
2019· Proceedings of the Royal Society B Biological Sciences406doi:10.1098/rspb.2019.0831

Proper biological interpretation of a phylogeny can sometimes hinge on the placement of key taxa-or fail when such key taxa are not sampled. In this light, we here present the first attempt to investigate (though not conclusively resolve) animal relationships using genome-scale data from all phyla. Results from the site-heterogeneous CAT + GTR model recapitulate many established major clades, and strongly confirm some recent discoveries, such as a monophyletic Lophophorata, and a sister group relationship between Gnathifera and Chaetognatha, raising continued questions on the nature of the spiralian ancestor. We also explore matrix construction with an eye towards testing specific relationships; this approach uniquely recovers support for Panarthropoda, and shows that Lophotrochozoa (a subclade of Spiralia) can be constructed in strongly conflicting ways using different taxon- and/or orthologue sets. Dayhoff-6 recoding sacrifices information, but can also reveal surprising outcomes, e.g. full support for a clade of Lophophorata and Entoprocta + Cycliophora, a clade of Placozoa + Cnidaria, and raising support for Ctenophora as sister group to the remaining Metazoa, in a manner dependent on the gene and/or taxon sampling of the matrix in question. Future work should test the hypothesis that the few remaining uncertainties in animal phylogeny might reflect violations of the various stationarity assumptions used in contemporary inference methods.

Isolation of Dolastatin 10 from the Marine Cyanobacterium <i>Symploca</i> Species VP642 and Total Stereochemistry and Biological Evaluation of Its Analogue Symplostatin 1
Hendrik Luesch, Richard E. Moore, Valerie J. Paul, Susan L. Mooberry +1 more
2001· Journal of Natural Products380doi:10.1021/np010049y

The potent antitumor agent dolastatin 10 (1) was originally isolated from the sea hare Dolabella auricularia, and we now report its isolation from the marine cyanobacterium Symploca sp. VP642 from Palau. The chemically related analogue symplostatin 1 (2) has been reisolated from Guamanian and Hawaiian varieties of S. hydnoides and its total stereochemistry completed by determining the N,N-dimethylisoleucine unit to be L. Symplostatin 1 (2), like dolastatin 10 (1), is a potent microtubule inhibitor. The antitumor activity of 2 was assessed in vivo against several murine tumors. Symplostatin 1 (2) was effective against a drug-insensitive mammary tumor and a drug-insensitive colon tumor; however, it was only slightly effective against two MDR tumors.

Total Structure Determination of Apratoxin A, a Potent Novel Cytotoxin from the Marine Cyanobacterium <i>Lyngbya </i><i>m</i><i>ajuscula</i>
Hendrik Luesch, Wesley Y. Yoshida, Richard E. Moore, Valerie J. Paul +1 more
2001· Journal of the American Chemical Society374doi:10.1021/ja010453j

Apratoxin A (1), a potent cytotoxin with a novel skeleton, has been isolated from the marine cyanobacterium Lyngbya majuscula Harvey ex Gomont. This cyclodepsipeptide of mixed peptide-polyketide biogenesis bears a thiazoline ring flanked by polyketide portions, one of which possesses an unusual methylation pattern. Its gross structure has been elucidated by spectral analysis, including various 2D NMR techniques. The absolute configurations of the amino acid-derived units were determined by chiral HPLC analysis of hydrolysis products. The relative stereochemistry of the new dihydroxylated fatty acid unit, 3,7-dihydroxy-2,5,8,8-tetramethylnonanoic acid, was elucidated by successful application of the J-based configuration analysis originally developed for acyclic organic compounds using carbon-proton spin-coupling constants ((2,3)J(C,H)) and proton-proton spin-coupling constants ((3)J(H,H)); its absolute stereochemistry was established by Mosher analysis. The conformation of 1 in solution was mimicked by molecular modeling, employing a combination of distance geometry and restrained molecular dynamics. Apratoxin A (1) possesses IC(50) values for in vitro cytotoxicity against human tumor cell lines ranging from 0.36 to 0.52 nM; however, it was only marginally active in vivo against a colon tumor and ineffective against a mammary tumor.

Modulation of In Vivo Striatal Transmitter Release by Nitric Oxide and Cyclic GMP
Rosalinda Guevara‐Guzmán, Piers C. Emson, Keith M. Kendrick
1994· Journal of Neurochemistry367doi:10.1046/j.1471-4159.1994.62020807.x

The effects of nitric oxide (NO) and cyclic GMP on in vivo transmitter release in the rat striatum were investigated using microdialysis sampling in urethane-anaesthetised animals. The NO release-inducing substances S-nitrosoacetylpenicillamine (SNAP), S-nitrosoglutathione (SNOG), and sodium nitroprusside (SNP) increased extracellular concentrations of aspartate (Asp), glutamate (Glu), gamma-aminobutyric acid (GABA), taurine (Tau), acetylcholine (ACh), and serotonin (5-HT). Dopamine (DA) concentrations were decreased by SNAP but were increased by SNOG and SNP. An NO scavenger, haemoglobin, blocked or reduced the effects of SNAP on transmitter release. However, the control carrier compounds for SNAP, SNOG, and SNAP (penicillamine, glutathione, and potassium ferricyanide, respectively, which do not induce release of NO) also increased GABA, Tau, DA, and 5-HT concentrations. When NO gas was given directly by dissolving it in degassed Ringer's solution, DA concentrations decreased significantly, and those of Asp, Glu, GABA, Tau, ACh, and 5-HT increased. These effects of NO gas were all inhibited by coadministration of haemoglobin and for GABA, Tau, ACh, and DA showed some calcium dependency. The cyclic GMP agonists 8-bromo-cyclic GMP and dibutryl-cyclic GMP stimulated dose-dependent increases in Asp, Glu, GABA, Tau, ACh, DA, and 5-HT concentrations. Increased striatal transmitter release in response to NO may therefore be mediated by its stimulatory action on cyclic GMP formation. NO inhibition of DA release may be mediated indirectly through its stimulation of local cholinergic and GABAergic neurones.

Ecotoxicology of tropical marine ecosystems
Esther C. Peters, Nancy J. Gassman, Julie Firman, Robert H. Richmond +1 more
1997· Environmental Toxicology and Chemistry361doi:10.1002/etc.5620160103

Abstract The negative effects of chemical contaminants on tropical marine ecosystems are of increasing concern as human populations expand adjacent to these communities. Watershed streams and ground water carry a variety of chemicals from agricultural, industrial, and domestic activities, while winds and currents transport pollutants from atmospheric and oceanic sources to these coastal ecosystems. The implications of the limited information available on impacts of chemical stressors on mangrove forests, seagrass meadows, and coral reefs are discussed in the context of ecosystem management and ecological risk assessment. Three classes of pollutants have received attention: heavy metals, petroleum, and synthetic organics such as herbicides and pesticides. Heavy metals have been detected in all three ecosystems, causing physiological stress, reduced reproductive success, and outright mortality in associated invertebrates and fishes. Oil spills have been responsible for the destruction of entire coastal shallow-water communities, with recovery requiring years. Herbicides are particularly detrimental to mangroves and seagrasses and adversely affect the animal-algal symbioses in corals. Pesticides interfere with chemical cues responsible for key biological processes, including reproduction and recruitment of a variety of organisms. Information is lacking with regard to long-term recovery, indicator species, and biomarkers for tropical communities. Critical areas that are beginning to be addressed include the development of appropriate benchmarks for risk assessment, baseline monitoring criteria, and effective management strategies to protect tropical marine ecosystems in the face of mounting anthropogenic disturbance.

An Exploratory Analysis of the Relationship between Tropical Storm Formation in the Western North Pacific and ENSO
Mark A. Lander
1994· Monthly Weather Review347doi:10.1175/1520-0493(1994)122<0636:aeaotr>2.0.co;2

El Niño-Southern Oscillation (ENSO)-related variations in the observed character (e.g., annual storm totals, preferred genesis region, etc.) of the tropical cyclone activity in the western North Pacific are sought. With respect to annual storm totals, no ENSO signal is found; with respect to genesis region, a strong relationship is found between ENSO indices and the zonal displacement of the annual mean genesis locations. ENSO indices during the first half of the calendar year were found to be weakly predictive of the number and genesis locations of tropical cyclones occurring from July through December.

Occurrence of beta-methylamino-l-alanine (BMAA) in ALS/PDC patients from Guam
Susan J. Murch, Paul Alan Cox, Sandra Anne Banack, John C. Steele +1 more
2004· Acta Neurologica Scandinavica346doi:10.1111/j.1600-0404.2004.00320.x

We tested the brain tissues of the Chamorro people of Guam who died of amyotrophic lateral sclerosis/Parkinsonism dimentia complex (ALS/PDC) for the neurotoxin beta-methylamino-l-alanine (BMAA). We used validated high-pressure liquid chromatography and liquid chromatography-mass spectrometry analyses to test well-characterized archival tissues of the superior frontal gyrus from eight Chamorros from Guam and a comparison group of 15 Canadians. BMAA was found as a free amino acid in 83% of Chamorro ALS/PDC patients (3-10 microg/g) as a protein-associated amino acid in 100% of the Chamorro individuals (149-1190 microg/g). Both forms of BMAA were also found at comparable levels in two Canadians who died of progressive neurodegenerative disease. BMAA, which is produced by cyanobacteria, may be associated with some cases of neurodegenerative disease.

Coral Reefs: Present Problems and Future Concerns Resulting from Anthropogenic Disturbance
Robert H. Richmond
1993· American Zoologist330doi:10.1093/icb/33.6.524

Coral reefs, with their vast diversity of invertebrate, vertebrate and algal species, have undoubtedly been subjected to natural disturbance since their appearance millions of years ago. Anthropogenic disturbance has been a factor affecting reefs for a fraction of that time, yet in terms of overall impact, may be of greater concern. Data on habitat destruction, pesticide and heavy metal accumulation, nutrient loading, sedimentation, runoff and related impacts of man's activities indicate that many coastal reefs are endangered by these processes through alterations in animal-algal symbioses, shifts in competitive interactions, direct mortality, reproductive failure, and insufficient recruitment. The death of corals critically affects reef communities, as corals provide an important trophic link as well as the main habitat structure. While natural disturbance is an important factor affecting reef interactions, species diversity and evolution, chronic anthropogenic disturbances combined with unsuitable environments for recovery, are of great concern. Physiological stress can be measured in corals in addition to outright mortality, allowing the impacts of specific disturbances to be assessed. Sufficientdata for distinguishing real problems from temporal variability are becoming available, allowing scientists to focus on practical solutions to problems in coral reef management and preservation.

Biodiversity on Oceanic Islands: Its Origin and Extinction<sup>1</sup>
Gustav Paulay
1994· American Zoologist276doi:10.1093/icb/34.1.134

SYNOPSIS. The isolation and small size of oceanic islands make them attractive models for studies of diversification; the sensitivity of their biota makes them important subjects for studies of extinction. I explore the origin of island biotas through dispersal and in situ diversification, and examine the fate of these biotas since human contact. Island biotas start out depauperate and disharmonic, facilitating the survival of relict taxa and stimulating adaptive radiations. The often highly restricted range and small population size of insular species, together with their limited diversity of defenses, make island biotas particularly vulnerable to extinction, largely through habitat loss or interactions with introduced species.

Host specificity in marine sponge‐associated bacteria, and potential implications for marine microbial diversity
Michael W. Taylor, Peter J. Schupp, Ingela Dahllöf, Staffan Kjelleberg +1 more
2003· Environmental Microbiology273doi:10.1046/j.1462-2920.2003.00545.x

Biodiversity is fundamental to both eukaryote and prokaryote ecology, yet investigations of diversity often differ markedly between the two disciplines. Host specificity - the association of organisms with only a few (specialism) or many (generalism) host species - is recognized within eukaryote ecology as a key determinant of diversity. In contrast, its implications for microbial diversity have received relatively little attention. Here we explore the relationship between microbial diversity and host specificity using marine sponge-bacteria associations. We used a replicated, hierarchical sampling design and both 16S rDNA- and rpoB-based denaturing gradient gel electrophoresis (DGGE) to examine whether three co-occurring sponges from temperate Australia -Cymbastela concentrica, Callyspongia sp. and Stylinos sp. - contained unique, specialized communities of microbes. Microbial communities varied little within each species of sponge, but variability among species was substantial. Over five seasons, the microbial community in C. concentrica differed significantly from other sponges, which were more similar to seawater. Overall, three types of sponge-associated bacteria were identified via 16S rDNA sequencing of excised DGGE bands: 'specialists'- found on only one host species, 'sponge associates'- found on multiple hosts but not in seawater, and 'generalists' from multiple hosts and seawater. Analogous to other high diversity systems, the degree of specificity of prokaryotes to host eukaryotes could have a potentially significant effect on estimates of marine microbial diversity.

The mental health and wellbeing of first generation migrants: a systematic-narrative review of reviews
Ciara Close, Anne Kouvonen, Tania Bosqui, Kishan Patel +2 more
2016· Globalization and Health256doi:10.1186/s12992-016-0187-3

BACKGROUND: First generation migrants are reportedly at higher risk of mental ill-health compared to the settled population. This paper systematically reviews and synthesizes all reviews on the mental health of first generation migrants in order to appraise the risk factors for, and explain differences in, the mental health of this population. METHODS: Scientific databases were searched for systematic reviews (inception-November 2015) which provided quantitative data on the mental ill-health of first generation migrants and associated risk factors. Two reviewers screened titles, abstracts and full text papers for their suitability against pre-specified criteria, methodological quality was assessed. RESULTS: One thousand eight hundred twenty articles were identified, eight met inclusion criteria, which were all moderate or low quality. Depression was mostly higher in first generation migrants in general, and in refugees/asylum seekers when analysed separately. However, for both groups there was wide variation in prevalence rates, from 5 to 44 % compared with prevalence rates of 8-12 % in the general population. Post-Traumatic Stress Disorder prevalence was higher for both first generation migrants in general and for refugees/asylum seekers compared with the settled majority. Post-Traumatic Stress Disorder prevalence in first generation migrants in general and refugees/ asylum seekers ranged from 9 to 36 % compared with reported prevalence rates of 1-2 % in the general population. Few studies presented anxiety prevalence rates in first generation migrants and there was wide variation in those that did. Prevalence ranged from 4 to 40 % compared with reported prevalence of 5 % in the general population. Two reviews assessed the psychotic disorder risk, reporting this was two to three times more likely in adult first generation migrants. However, one review on the risk of schizophrenia in refugees reported similar prevalence rates (2 %) to estimates of prevalence among the settled majority (3 %). Risk factors for mental ill-health included low Gross National Product in the host country, downward social mobility, country of origin, and host country. CONCLUSION: First generation migrants may be at increased risk of mental illness and public health policy must account for this and influencing factors. High quality research in the area is urgently needed as is the use of culturally specific validated measurement tools for assessing migrant mental health.

Destruction of Pacific Corals by the Sea Star <i>Acanthaster planci</i>
Richard H. Chesher
1969· Science251doi:10.1126/science.165.3890.280

Acanthaster planci, a coral predator, is undergoing a population explosion in many areas of the Pacific Ocean. Data on feeding rates, population movements, and stages of infestation were collected along coral reefs of Guam and Palau. Direct observations on destruction of Guam's coral reefs indicate that narrow, fringing reefs may be killed as rapidly as 1 kilometer per month. In a 2(1/2)-year period, 90 percent of the coral was killed along 38 kilometers of Guam's shoreline.

The first settlement of Remote Oceania: the Philippines to the Marianas
Hsiao‐chun Hung, Mike T. Carson, Peter Bellwood, Fredeliza Z. Campos +4 more
2011· Antiquity225doi:10.1017/s0003598x00068393

The authors compare pottery assemblages in the Marianas and the Philippines to claim endorsement for a first human expansion into the open Pacific around 1500 BC. The Marianas are separated from the Philippines by 2300km of open sea, so they are proposing an epic pioneering voyage of men and women, with presumably some cultivated plants but apparently no animals. How did they manage this unprecedented journey?

Marine Biofilm Bacteria Evade Eukaryotic Predation by Targeted Chemical Defense
Carsten Matz, Jeremy S. Webb, Peter J. Schupp, Shui Yen Phang +4 more
2008· PLoS ONE224doi:10.1371/journal.pone.0002744

Many plants and animals are defended from predation or herbivory by inhibitory secondary metabolites, which in the marine environment are very common among sessile organisms. Among bacteria, where there is the greatest metabolic potential, little is known about chemical defenses against bacterivorous consumers. An emerging hypothesis is that sessile bacterial communities organized as biofilms serve as bacterial refuge from predation. By testing growth and survival of two common bacterivorous nanoflagellates, we find evidence that chemically mediated resistance against protozoan predators is common among biofilm populations in a diverse set of marine bacteria. Using bioassay-guided chemical and genetic analysis, we identified one of the most effective antiprotozoal compounds as violacein, an alkaloid that we demonstrate is produced predominately within biofilm cells. Nanomolar concentrations of violacein inhibit protozoan feeding by inducing a conserved eukaryotic cell death program. Such biofilm-specific chemical defenses could contribute to the successful persistence of biofilm bacteria in various environments and provide the ecological and evolutionary context for a number of eukaryote-targeting bacterial metabolites.

The effects of semantic and thematic clustering on the learning of second language vocabulary
Thomas Tinkham
1997· Second language Research222doi:10.1191/026765897672376469

ESL students are often presented much of their new English vocabulary preorganized for them in ‘semantic clusters’, sets of semantically and syntactically similar words, e.g., eye, nose, ear, mouth, chin. Although clustering of this sort facilitates the activities which serve current approaches to language teaching and would seem,at first glance, to facilitate vocabulary learning as well, little or no empirical justification is offered by researchers in support of its employment. In fact, research that might apply, psychological research generated by interference theory, would predict that such clustering of similar items impedes rather than enhances learning. On a more positive note, a more ‘thematic’ manner of organizing new L2 vocabulary is suggested by more recent psychological research which would predict that clusters like frog, green,hop, pond,slippery, croak would be more easily learnt than groups of unassociated words. With these predictions in mind,the reported research explored the effects upon L2 vocabulary learning of both ‘semantic’ and ‘thematic’ clustering. The results provide a wide range of evidence that suggests that semantic clustering does indeed serve as a hindrance while thematic clustering serves as a facilitator of new language vocabulary learning.