Tanner C.E.,St. Marys College of Maryland |
Parham T.,580 Taylor Avenue
Restoration Ecology | Year: 2010
The use of aquaculture systems to grow the seagrass Zostera marina (eelgrass) from seeds for restoration projects was evaluated through laboratory and mesocosm studies. Along the mid-Atlantic coast of North America Z. marina seeds are shed from late spring through early summer, but seeds typically do not begin to germinate until the late fall. Fall is the optimal season to plant both seeds and shoots in this region. We conducted studies to determine if Z. marina seeds can be induced to germinate in the summer and seedlings grown in mesocosms to a size sufficiently large enough for out-planting in the fall. Seeds in soil-less culture germinated in the summer when held at 14°C, with percent germination increasing with lower salinities. Cold storage (4°C) of seeds prior to planting in sediments enhanced germination and seedling survival. Growth rates of seedlings were significantly higher in nutrient enriched estuarine sediments. Results from preliminary studies were used in designing a large-scale culture project in which 15,000 shoots were grown and out-planted into the Potomac River estuary in the Chesapeake Bay and compared with an equal number of transplanted shoots. These studies demonstrate that growing Z. marina from seeds is an alternative approach to harvesting plants from donor beds when vegetative shoots are required for restoration projects. © 2010 Society for Ecological Restoration International.
Roberts W.C.,St. Marys College of Maryland |
Schwab-Stone M.E.,Yale University
Social Psychiatry and Psychiatric Epidemiology | Year: 2011
Background: Community violence exposure among youth can lead to various negative outcomes, including post-traumatic stress symptoms. Research in the Western world indicates that a number of social support factors may moderate the relation between violence exposure and internalizing symptoms. Little research has been carried out in non-Western countries. This study aimed to fill this gap by exploring the relations among violence exposure, parental warmth, positive school climate, and post-traumatic stress reactions among youth in The Republic of The Gambia, Africa. Methods: A school-based survey of youth behaviors, feelings, attitudes, and perceptions was administered to 653 students at senior secondary schools in four Gambian communities. Results: Students reported high levels of exposure to violence. Over half of students reported witnessing someone threatened with serious physical harm, beaten up or mugged, attacked or stabbed with a knife/piece of glass, or seriously wounded in an incident of violence. Nearly half of students reported being beaten up or mugged during the past year, and nearly a quarter reported being threatened with serious physical harm. There were no sex differences in levels of exposure. Traumatic stress symptoms were common, especially among females. Both violence witnessing and violent victimization significantly predicted post-traumatic stress symptoms, and positive school climate moderated the relationship. Among youth victimized by violence, positive school climate was most strongly correlated with lower levels of post-traumatic stress at low levels of exposure. Among youth who had witnessed violence, positive school climate was most strongly correlated with lower levels of post-traumatic stress at high levels of exposure. Conclusion: Community-based programs that bring together parents, schools, and youth may play an important role in combating the negative effects of some types of violence exposure among Gambian youth. Youth experiencing high levels of violent victimization represent a sample of particular concern and merit special research and clinical attention. © 2009 Springer-Verlag.
Kose E.,St. Marys College of Maryland |
Perline R.K.,Drexel University
Applied Optics | Year: 2014
We compute a family of double-mirror catadioptric sensors with ultrawide field of view and no distortion. The two concentric mirrors are rotationally symmetric, and the inside mirror is a revolved conic section. The mapping between the object and the image planes was linear, hence the lack of distortion. The equations describing the outer mirror were determined by the projection induced by the inside mirror and the rectifying property of the sensor. Solving the resulting nonlinear ordinary differential equations yielded the cross section of the secondary mirror. The sensors we present require no further digital processing. © 2014 Optical Society of America.
Pfordresher P.Q.,State University of New York at Buffalo |
Mantell J.T.,St. Marys College of Maryland
Cognitive Psychology | Year: 2014
Singing is a ubiquitous and culturally significant activity that humans engage in from an early age. Nevertheless, some individuals - termed poor-pitch singers - are unable to match target pitches within a musical semitone while singing. In the experiments reported here, we tested whether poor-pitch singing deficits would be reduced when individuals imitate recordings of themselves as opposed to recordings of other individuals. This prediction was based on the hypothesis that poor-pitch singers have not developed an abstract "inverse model" of the auditory-vocal system and instead must rely on sensorimotor associations that they have experienced directly, which is true for sequences an individual has already produced. In three experiments, participants, both accurate and poor-pitch singers, were better able to imitate sung recordings of themselves than sung recordings of other singers. However, this self-advantage was enhanced for poor-pitch singers. These effects were not a byproduct of self-recognition (Experiment 1), vocal timbre (Experiment 2), or the absolute pitch of target recordings (i.e., the advantage remains when recordings are transposed, Experiment 3). Results support the conceptualization of poor-pitch singing as an imitative deficit resulting from a deficient inverse model of the auditory-vocal system with respect to pitch. © 2014 Elsevier Inc.
Sasmal P.K.,University of Marburg |
Streu C.N.,St. Marys College of Maryland |
Meggers E.,University of Marburg |
Meggers E.,Xiamen University
Chemical Communications | Year: 2013
This feature article discusses synthetic metal complexes that are capable of catalyzing chemical transformations in living organisms. Photodynamic therapy exemplifies what is probably the most established artificial catalytic process exploited in medicine, namely the photosensitized catalytic generation of cell-damaging singlet oxygen. Different redox catalysts have been designed over the last two decades to target a variety of redox alterations in cancer and other diseases. For example, pentaazamacrocyclic manganese(ii) complexes catalyze the dismutation of superoxide to O2 and H2O 2in vivo and thus reduce oxidative stress in analogy to the native enzyme superoxide dismutase. Recently, piano-stool ruthenium and iridium complexes were reported to influence cellular redox homeostasis indirectly by catalytic glutathione oxidation and catalytic transfer hydrogenation using the coenzyme NADH, respectively. Over the last few years, significant progress has been made towards the application of non-biological reactions in living systems, ranging from the organoruthenium-catalyzed cleavage of allylcarbamates and a gold-catalyzed intramolecular hydroarylation to palladium-catalyzed Suzuki-Miyaura and Sonogashira cross-couplings within the cytoplasm or on the surface of living cells. The design of bioorthogonal catalyst/substrate pairs, which can passively diffuse into cells, combines the advantages of small molecules with catalysis and promises to provide exciting new tools for future chemical biology studies. This journal is © The Royal Society of Chemistry 2013.