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• 1061. [Article] Numerical study of natural convection in square partitioned and non-partitioned enclosures

  Heat transfer characteristics and associated temperature and flow fields for natural convection in two-dimensional, square, partitioned and non-partitioned enclosures have been determined for Grashof numbers ...

  Citation × Citation Citation Abstract Copy Title: Numerical study of natural convection in square partitioned and non-partitioned enclosures Author: Sukkaset, Prasart Heat transfer characteristics and associated temperature and flow fields for natural convection in two-dimensional, square, partitioned and non-partitioned enclosures have been determined for Grashof numbers ranging from 10³ to 10⁶. The vertical side walls of the enclosure are isothermal with all other surfaces assumed to be adiabatic. An adiabatic partition is oriented vertically with one edge on the enclosure floor. The dimensions and location of the partition were varied in order to investigate its effect of natural convection in the enclosure. Air was taken as the working fluid. Transport equations for vorticity and energy were solved using the QUICKEST scheme while the Poisson equation, for the steamfunction, was solved using the SOR method. For any Grashof number, temperature and flow fields in the region above the partition are not significantly different from those of the non-partitioned enclosure in the case of an aperture ratio of 0.75 or greater. An increase in the partition height or width results in modifying the temperature and flow fields and decreasing the average heat transfer across the enclosure. Title: Numerical study of natural convection in square partitioned and non-partitioned enclosures Author: Sukkaset, Prasart Heat transfer characteristics and associated temperature and flow fields for natural convection in two-dimensional, square, partitioned and non-partitioned enclosures have been determined for Grashof numbers ranging from 10³ to 10⁶. The vertical side walls of the enclosure are isothermal with all other surfaces assumed to be adiabatic. An adiabatic partition is oriented vertically with one edge on the enclosure floor. The dimensions and location of the partition were varied in order to investigate its effect of natural convection in the enclosure. Air was taken as the working fluid. Transport equations for vorticity and energy were solved using the QUICKEST scheme while the Poisson equation, for the steamfunction, was solved using the SOR method. For any Grashof number, temperature and flow fields in the region above the partition are not significantly different from those of the non-partitioned enclosure in the case of an aperture ratio of 0.75 or greater. An increase in the partition height or width results in modifying the temperature and flow fields and decreasing the average heat transfer across the enclosure. Close

• 1062. [Article] Effects of spatial scale and heterogeneity on avian occupancy dynamics and population trends in forested mountain landscapes

  Population trends and patterns in species distributions are the major currencies used to examine responses by biodiversity to changing environments. Effective conservation recommendations require that ...

  Citation × Citation Citation Abstract Copy Title: Effects of spatial scale and heterogeneity on avian occupancy dynamics and population trends in forested mountain landscapes Author: Frey, Sarah Jean Kiuama Population trends and patterns in species distributions are the major currencies used to examine responses by biodiversity to changing environments. Effective conservation recommendations require that models of both distribution dynamics and population trends accurately reflect reality. However, identification of the appropriate temporal and spatial scales of animal response, and then obtaining data at these scales present two major challenges to developing predictive models. In heterogeneous forested mountain landscapes I examined: A) the relative drivers of climatic variability at fine spatial scales under the forest canopy ('microclimate'), B) the influence of microclimate on local-scale occupancy dynamics of bird communities, and C) the effects of spatial scale and imperfect bird detection on long-term avian population trends. Climate change has been predicted to cause widespread biodiversity declines. However, the capacity of climate envelope models for predicting the future of biodiversity has been questioned due to the mismatch between the scale of available data (i.e., global climate models) and the scales at which organisms experience their environment. Local-scale variation in microclimate is hypothesized to provide potential ‘microrefugia’ for biodiversity, but the relative role of elevation, microtopography, and vegetation structure in driving microclimate is not well known. If the microrefugia hypothesis is true, I expected to see areas on the landscape that remained relatively cooler (i.e., buffered sites). To test this, I collected temperature data at 183 sites across elevation and forest structure gradients in complex terrain of the H. J. Andrews Experimental Forest in the Cascade Mountains of Oregon, USA (Chapter 2). I used boosted regression trees, a novel machine learning approach, to determine the relative influence of vegetation structure, microtopography, and elevation as drivers of microclimate and mapped fine-scale distributions of temperature across the landscape. Models performed extremely well on independent data - cross-validation correlations between testing and training data were 0.69 - 0.98 for ten selected climate variables. Elevation was the dominant driver in fine-scale microclimate patterns, although vegetation and microtopography also showed substantial relative influences. For instance, during the spring-summer transition, maximum monthly temperatures observed in old-growth sites were 2.6°C (95% CI: 1.8 - 3.3°C) cooler than plantation sites and minimum temperatures during winter months were 0.6°C (95% CI: 0.4 - 0.8°C) warmer. This suggests that older forest stands mediate changes in temperature by buffering against warming during summer months and moderating cold temperatures during the winter. Climate is generally considered most influential on species distributions at large spatial scales; however much microclimate variability exists within regional patterns. I tested whether this high degree of microclimate variability has relevance for predicting species distributions and occupancy dynamics of the Andrews Forest bird community. I collected bird occurrence data in 2012 and 2013 at all 183 sites with fine-scale temperature measurements. I used dynamic occupancy models to test the effects of temperature on occupancy and apparent within-season bird movement while statistically accounting for vegetation effects and imperfect bird detection (Chapter 3). Most species (87%) exhibited within-season shifts in response to local-scale temperature metrics. Effects of temperature on within-season occupancy dynamics were as large or larger (1 to 1.7 times) than vegetation. However, individual species were almost as likely to shift toward warmer sites as toward cooler sites, suggesting that microclimate preferences are species-specific. My results emphasize that high-resolution temperature data provide valuable insight into avian distribution dynamics in montane forest environments and that microclimate is an important variable in breeding season habitat selection by forest birds. I hypothesize that microclimate-associated distribution shifts may reflect species' potential for behavioral buffering from climate change in complex terrain. Factors influencing population trends often differ depending on the spatial scale under consideration. Further, accurate estimation of trends requires accounting for biases caused by imperfect detection. To test the degree to which population trends are consistent across scales, I estimated landscape-scale bird population trends from 1999-2012 for 38 species at the Hubbard Brook Experimental Forest (HBEF) in the White Mountains of New Hampshire, USA and compared them to regional and local trends (Chapter 4). I used a new method - open-population binomial mixture models - to test the hypothesis that imperfect detection in bird sampling has the potential to bias trend estimates. I also tested for generalities in species responses by predicting population trends as a function of life history and ecological traits. Landscape-scale trends were correlated with regional and local trends, but generally these correlations were weak (r = 0.12 - 0.4). Further, more species were declining at the regional scale compared to within the relatively undisturbed HBEF. Life history and ecological traits did not explain any of the variability in the HBEF trends. However, at the regional scale, species that occurred at higher elevations were more likely to be declining and species associated with older forests have increased. I hypothesize that these differences could be attributed to both elevated rates of land-use change in the broader region and the fact that the structure of regional data did not permit modeling of imperfect detection. Indeed, accounting for imperfect detection resulted in more accurate population trend estimates at the landscape scale; without accounting for detection we would have both missed trends and falsely identified trends where none existed. These results highlight two important cautions for trend analysis: 1) population trends estimated at fine spatial scales may not be extrapolated to broader scales and 2) accurate trends require accounting for imperfect detection. Title: Effects of spatial scale and heterogeneity on avian occupancy dynamics and population trends in forested mountain landscapes Author: Frey, Sarah Jean Kiuama Population trends and patterns in species distributions are the major currencies used to examine responses by biodiversity to changing environments. Effective conservation recommendations require that models of both distribution dynamics and population trends accurately reflect reality. However, identification of the appropriate temporal and spatial scales of animal response, and then obtaining data at these scales present two major challenges to developing predictive models. In heterogeneous forested mountain landscapes I examined: A) the relative drivers of climatic variability at fine spatial scales under the forest canopy ('microclimate'), B) the influence of microclimate on local-scale occupancy dynamics of bird communities, and C) the effects of spatial scale and imperfect bird detection on long-term avian population trends. Climate change has been predicted to cause widespread biodiversity declines. However, the capacity of climate envelope models for predicting the future of biodiversity has been questioned due to the mismatch between the scale of available data (i.e., global climate models) and the scales at which organisms experience their environment. Local-scale variation in microclimate is hypothesized to provide potential ‘microrefugia’ for biodiversity, but the relative role of elevation, microtopography, and vegetation structure in driving microclimate is not well known. If the microrefugia hypothesis is true, I expected to see areas on the landscape that remained relatively cooler (i.e., buffered sites). To test this, I collected temperature data at 183 sites across elevation and forest structure gradients in complex terrain of the H. J. Andrews Experimental Forest in the Cascade Mountains of Oregon, USA (Chapter 2). I used boosted regression trees, a novel machine learning approach, to determine the relative influence of vegetation structure, microtopography, and elevation as drivers of microclimate and mapped fine-scale distributions of temperature across the landscape. Models performed extremely well on independent data - cross-validation correlations between testing and training data were 0.69 - 0.98 for ten selected climate variables. Elevation was the dominant driver in fine-scale microclimate patterns, although vegetation and microtopography also showed substantial relative influences. For instance, during the spring-summer transition, maximum monthly temperatures observed in old-growth sites were 2.6°C (95% CI: 1.8 - 3.3°C) cooler than plantation sites and minimum temperatures during winter months were 0.6°C (95% CI: 0.4 - 0.8°C) warmer. This suggests that older forest stands mediate changes in temperature by buffering against warming during summer months and moderating cold temperatures during the winter. Climate is generally considered most influential on species distributions at large spatial scales; however much microclimate variability exists within regional patterns. I tested whether this high degree of microclimate variability has relevance for predicting species distributions and occupancy dynamics of the Andrews Forest bird community. I collected bird occurrence data in 2012 and 2013 at all 183 sites with fine-scale temperature measurements. I used dynamic occupancy models to test the effects of temperature on occupancy and apparent within-season bird movement while statistically accounting for vegetation effects and imperfect bird detection (Chapter 3). Most species (87%) exhibited within-season shifts in response to local-scale temperature metrics. Effects of temperature on within-season occupancy dynamics were as large or larger (1 to 1.7 times) than vegetation. However, individual species were almost as likely to shift toward warmer sites as toward cooler sites, suggesting that microclimate preferences are species-specific. My results emphasize that high-resolution temperature data provide valuable insight into avian distribution dynamics in montane forest environments and that microclimate is an important variable in breeding season habitat selection by forest birds. I hypothesize that microclimate-associated distribution shifts may reflect species' potential for behavioral buffering from climate change in complex terrain. Factors influencing population trends often differ depending on the spatial scale under consideration. Further, accurate estimation of trends requires accounting for biases caused by imperfect detection. To test the degree to which population trends are consistent across scales, I estimated landscape-scale bird population trends from 1999-2012 for 38 species at the Hubbard Brook Experimental Forest (HBEF) in the White Mountains of New Hampshire, USA and compared them to regional and local trends (Chapter 4). I used a new method - open-population binomial mixture models - to test the hypothesis that imperfect detection in bird sampling has the potential to bias trend estimates. I also tested for generalities in species responses by predicting population trends as a function of life history and ecological traits. Landscape-scale trends were correlated with regional and local trends, but generally these correlations were weak (r = 0.12 - 0.4). Further, more species were declining at the regional scale compared to within the relatively undisturbed HBEF. Life history and ecological traits did not explain any of the variability in the HBEF trends. However, at the regional scale, species that occurred at higher elevations were more likely to be declining and species associated with older forests have increased. I hypothesize that these differences could be attributed to both elevated rates of land-use change in the broader region and the fact that the structure of regional data did not permit modeling of imperfect detection. Indeed, accounting for imperfect detection resulted in more accurate population trend estimates at the landscape scale; without accounting for detection we would have both missed trends and falsely identified trends where none existed. These results highlight two important cautions for trend analysis: 1) population trends estimated at fine spatial scales may not be extrapolated to broader scales and 2) accurate trends require accounting for imperfect detection. Close

• 1063. [Article] Optimization of feeding schedules for coho salmon in the hatchery environment

  A growth model is developed for coho salmon which accounts for temperatures and feeding rates typically encountered in fish hatchery operation. Feeding rates utilized by the model ranged from maintenance ...

  Citation × Citation Citation Abstract Copy Title: Optimization of feeding schedules for coho salmon in the hatchery environment Author: Corey, Philip David A growth model is developed for coho salmon which accounts for temperatures and feeding rates typically encountered in fish hatchery operation. Feeding rates utilized by the model ranged from maintenance to maximum utilizable rations. The model is derived from an empirical equation for maximum growth rate, and a theoretical equation for net energy utilization. The resultant equation is modified to improve fit at higher feeding levels. Calibration is accomplished with experimentally obtained data. The model is similar to one developed by G.D. Stauffer, but represents an improvement because points on the growth curve between maintenance and maximum ration can be fitted even if maintenance and maximum requirements are obtained independently. An optimization method is then developed using this growth model that determines, for a given temperature regime, a feeding schedule that minimizes total food consumption for a given rearing period. The method is then extended to determine simultaneously feeding schedules and temperature regimes that minimize total food consumption. Title: Optimization of feeding schedules for coho salmon in the hatchery environment Author: Corey, Philip David A growth model is developed for coho salmon which accounts for temperatures and feeding rates typically encountered in fish hatchery operation. Feeding rates utilized by the model ranged from maintenance to maximum utilizable rations. The model is derived from an empirical equation for maximum growth rate, and a theoretical equation for net energy utilization. The resultant equation is modified to improve fit at higher feeding levels. Calibration is accomplished with experimentally obtained data. The model is similar to one developed by G.D. Stauffer, but represents an improvement because points on the growth curve between maintenance and maximum ration can be fitted even if maintenance and maximum requirements are obtained independently. An optimization method is then developed using this growth model that determines, for a given temperature regime, a feeding schedule that minimizes total food consumption for a given rearing period. The method is then extended to determine simultaneously feeding schedules and temperature regimes that minimize total food consumption. Close

• 1064. [Article] Studies on the germination and growth of Anisogramma anomala Peck (Muller) in vitro

  This study examined the effects of pH, temperature, washing, and post-hydration drying on germination of Anisogramma anomala ascopores. Spores germinate most readily in the temperature range of 5 to 15 ...

  Citation × Citation Citation Abstract Copy Title: Studies on the germination and growth of Anisogramma anomala Peck (Muller) in vitro Author: Lightfoot, Richard (Richard Thomas), 1958- This study examined the effects of pH, temperature, washing, and post-hydration drying on germination of Anisogramma anomala ascopores. Spores germinate most readily in the temperature range of 5 to 15 degrees C, with an optimal temperature of 10 degrees (1 sd=0.05). Growth was best in the pH range of 5 to 6. Washed ascopores germinate at significantly higher rates than unwashed spores (P=.05, .01, and .06 for three experiments). Germination rate declined sharply with increasing post-hydration drying, with 5 minutes of drying resulting in a 45% reduction in germination. After one hour of drying, spore germination was reduced by 98.5%. Those environmental factors which were optimal for germination in vitro reflected prevailing field conditions during the natural host infection period. The growth of A. anomala on artificial meduium is described. The germination process includes the following series of events: (1) spore hydration and swelling, (2) emergence of the germ tube, (3) vesicle formation, (4) production of hyphal initials, and (5) hyphal growth. Attempts to maintain cultures of A. anomala for longer than several months were unsuccessful. Title: Studies on the germination and growth of Anisogramma anomala Peck (Muller) in vitro Author: Lightfoot, Richard (Richard Thomas), 1958- This study examined the effects of pH, temperature, washing, and post-hydration drying on germination of Anisogramma anomala ascopores. Spores germinate most readily in the temperature range of 5 to 15 degrees C, with an optimal temperature of 10 degrees (1 sd=0.05). Growth was best in the pH range of 5 to 6. Washed ascopores germinate at significantly higher rates than unwashed spores (P=.05, .01, and .06 for three experiments). Germination rate declined sharply with increasing post-hydration drying, with 5 minutes of drying resulting in a 45% reduction in germination. After one hour of drying, spore germination was reduced by 98.5%. Those environmental factors which were optimal for germination in vitro reflected prevailing field conditions during the natural host infection period. The growth of A. anomala on artificial meduium is described. The germination process includes the following series of events: (1) spore hydration and swelling, (2) emergence of the germ tube, (3) vesicle formation, (4) production of hyphal initials, and (5) hyphal growth. Attempts to maintain cultures of A. anomala for longer than several months were unsuccessful. Close

• 1065. [Article] Estimation of transmission dynamics of the Ceratomyxa shasta actinospore to the salmonid host

  This is the publisher’s final pdf. The published article is copyrighted by Cambridge University Press and can be found at: http://www.cambridge.org/.

  Citation × Citation Citation Abstract Copy Title: Estimation of transmission dynamics of the Ceratomyxa shasta actinospore to the salmonid host Author: Bartholomew, J. L., Ray, R. A. This is the publisher’s final pdf. The published article is copyrighted by Cambridge University Press and can be found at: http://www.cambridge.org/. Title: Estimation of transmission dynamics of the Ceratomyxa shasta actinospore to the salmonid host Author: Bartholomew, J. L., Ray, R. A. This is the publisher’s final pdf. The published article is copyrighted by Cambridge University Press and can be found at: http://www.cambridge.org/. Close

• 1066. [Article] High-resolution wind speed measurements using actively heated fiber optics

  Supporting information is available online at: http://onlinelibrary.wiley.com/doi/10.1002/2015GL066729

  Citation × Citation Citation Abstract Copy Title: High-resolution wind speed measurements using actively heated fiber optics Author: Thomas, Christoph K., Wagner, James, Selker, John, Sayde, Chadi Supporting information is available online at: http://onlinelibrary.wiley.com/doi/10.1002/2015GL066729 Title: High-resolution wind speed measurements using actively heated fiber optics Author: Thomas, Christoph K., Wagner, James, Selker, John, Sayde, Chadi Supporting information is available online at: http://onlinelibrary.wiley.com/doi/10.1002/2015GL066729 Close

• 1067. [Article] Genetic selection for avian embryo development at an elevated temperature

  A genetic selection study to determine the effects on egg hatchability and subsequent chick performance of Japanese quail eggs incubated at a 38.9° C (102° F) dry bulb temperature (Selected, S) when compared ...

  Citation × Citation Citation Abstract Copy Title: Genetic selection for avian embryo development at an elevated temperature Author: Colvin, Wendy R. A genetic selection study to determine the effects on egg hatchability and subsequent chick performance of Japanese quail eggs incubated at a 38.9° C (102° F) dry bulb temperature (Selected, S) when compared to 37.8 C (100°F) (Control, C) was conducted for four consecutive generations. Eggs from a randomly mated population of Japanese quail were randomly allocated to the two treatment groups and incubated in dedicated Jamesway 252 units for the first 14 days then transferred to a common hatcher 36.9° C (98.5° F). Using family-based selection, the chicks that hatched from the two lines were subsequently used as breeders (25 pair matings/line) and the resulting eggs incubated at their respective temperatures. After four consecutive generations, percent egg fertility, percent early dead embryos (1 -7days), and percent hatch of fertile eggs were numerically higher in line C vs. S. While total development time was reduced in line S vs. C by 24 hours, mean egg weight and body weight were higher (p < 0.01) and age to first egg was reduced in line S. Title: Genetic selection for avian embryo development at an elevated temperature Author: Colvin, Wendy R. A genetic selection study to determine the effects on egg hatchability and subsequent chick performance of Japanese quail eggs incubated at a 38.9° C (102° F) dry bulb temperature (Selected, S) when compared to 37.8 C (100°F) (Control, C) was conducted for four consecutive generations. Eggs from a randomly mated population of Japanese quail were randomly allocated to the two treatment groups and incubated in dedicated Jamesway 252 units for the first 14 days then transferred to a common hatcher 36.9° C (98.5° F). Using family-based selection, the chicks that hatched from the two lines were subsequently used as breeders (25 pair matings/line) and the resulting eggs incubated at their respective temperatures. After four consecutive generations, percent egg fertility, percent early dead embryos (1 -7days), and percent hatch of fertile eggs were numerically higher in line C vs. S. While total development time was reduced in line S vs. C by 24 hours, mean egg weight and body weight were higher (p < 0.01) and age to first egg was reduced in line S. Close

• 1068. [Article] Variations of δ¹⁸O in rainwater from southwestern Oregon

  We examine the relation between δ¹⁸O in rainwater collected in southwestern Oregon and climate variables including temperature, parcel trajectory, precipitation amount, and specific humidity. Local surface ...

  Citation × Citation Citation Abstract Copy Title: Variations of δ¹⁸O in rainwater from southwestern Oregon Author: Clark, Peter U., Ersek, Vasile, Mix, Alan C. We examine the relation between δ¹⁸O in rainwater collected in southwestern Oregon and climate variables including temperature, parcel trajectory, precipitation amount, and specific humidity. Local surface air temperature at the time of sample collection explains a large proportion of δ¹⁸O variability, suggesting that paleoclimatic archives that are related to rainfall δ¹⁸O should be useful for qualitative temperature reconstructions. Models of Rayleigh distillation of air masses originating in the North Pacific can broadly constrain the observed isotopic variability in southwestern Oregon. Results from a Hybrid Single‐ Particle Lagrangian Integrated Trajectory Model suggest that recent parcel pathways have little influence on the isotopic composition of precipitation collected at our site. We also find no significant relation between rainfall d18O and precipitation amount. Changes in specific humidity along the parcel tracks, however, indicate that the water vapor exchange of the air mass with the underlying ocean influenced the isotopic composition of the most enriched samples. Title: Variations of δ¹⁸O in rainwater from southwestern Oregon Author: Clark, Peter U., Ersek, Vasile, Mix, Alan C. We examine the relation between δ¹⁸O in rainwater collected in southwestern Oregon and climate variables including temperature, parcel trajectory, precipitation amount, and specific humidity. Local surface air temperature at the time of sample collection explains a large proportion of δ¹⁸O variability, suggesting that paleoclimatic archives that are related to rainfall δ¹⁸O should be useful for qualitative temperature reconstructions. Models of Rayleigh distillation of air masses originating in the North Pacific can broadly constrain the observed isotopic variability in southwestern Oregon. Results from a Hybrid Single‐ Particle Lagrangian Integrated Trajectory Model suggest that recent parcel pathways have little influence on the isotopic composition of precipitation collected at our site. We also find no significant relation between rainfall d18O and precipitation amount. Changes in specific humidity along the parcel tracks, however, indicate that the water vapor exchange of the air mass with the underlying ocean influenced the isotopic composition of the most enriched samples. Close

• 1069. [Article] Anthropogenic influence on the changing likelihood of an exceptionally warm summer in Texas, 2011

  This is the publisher’s final pdf. The published article is copyrighted by the American Geophysical Union and can be found at: http://agupubs.onlinelibrary.wiley.com/agu/journal/10.1002/%28ISSN%291944-...

  Citation × Citation Citation Abstract Copy Title: Anthropogenic influence on the changing likelihood of an exceptionally warm summer in Texas, 2011 Author: Massey, Neil, Rupp, David E., Allen, Myles, Mote, Philip W., Li, Sihan, Sparrow, Sarah N. This is the publisher’s final pdf. The published article is copyrighted by the American Geophysical Union and can be found at: http://agupubs.onlinelibrary.wiley.com/agu/journal/10.1002/%28ISSN%291944-8007/ Title: Anthropogenic influence on the changing likelihood of an exceptionally warm summer in Texas, 2011 Author: Massey, Neil, Rupp, David E., Allen, Myles, Mote, Philip W., Li, Sihan, Sparrow, Sarah N. This is the publisher’s final pdf. The published article is copyrighted by the American Geophysical Union and can be found at: http://agupubs.onlinelibrary.wiley.com/agu/journal/10.1002/%28ISSN%291944-8007/ Close

• 1070. [Article] Room temperature multiferroic properties of single-phase (Bi₀.₉La₀.₁)FeO₃-Ba(Fe₀.₅Nb₀.₅)O₃ solid solution ceramics

  Article appears in Applied Physics Letters (http://apl.aip.org/) and is copyrighted by American Institute of Physics (http://www.aip.org/).

  Citation × Citation Citation Abstract Copy Title: Room temperature multiferroic properties of single-phase (Bi₀.₉La₀.₁)FeO₃-Ba(Fe₀.₅Nb₀.₅)O₃ solid solution ceramics Author: No, Kwangsoo, Paik, Hanjong, Hwang, Hosung, Kwon, Seunghwa, Cann, David P. Article appears in Applied Physics Letters (http://apl.aip.org/) and is copyrighted by American Institute of Physics (http://www.aip.org/). Title: Room temperature multiferroic properties of single-phase (Bi₀.₉La₀.₁)FeO₃-Ba(Fe₀.₅Nb₀.₅)O₃ solid solution ceramics Author: No, Kwangsoo, Paik, Hanjong, Hwang, Hosung, Kwon, Seunghwa, Cann, David P. Article appears in Applied Physics Letters (http://apl.aip.org/) and is copyrighted by American Institute of Physics (http://www.aip.org/). Close