Contour Integration over Time: Psychophysical and fMRI Evidence.

The brain integrates discrete but collinear stimuli to perceive global contours. Previous contour integration (CI) studies mainly focus on integration over space, and CI is attributed to either V1 long-range connections or contour processing in high-visual areas that top-down modulate V1 responses. Here, we show that CI also occurs over time in a design that minimizes the roles of V1 long-range interactions. We use tilted contours embedded in random orientation noise and moving horizontally behind a fixed vertical slit. Individual contour elements traveling up/down within the slit would be encoded over time by parallel, rather than aligned, V1 neurons. However, we find robust contour detection even when the slit permits only one viewable contour element. Similar to CI over space, CI over time also obeys the rule of collinearity. fMRI evidence shows that while CI over space engages visual areas as early as V1, CI over time mainly engages higher dorsal and ventral visual areas involved in shape processing, as well as posterior parietal regions involved in visual memory that can represent the orientation of temporally integrated contours. These results suggest at least partially dissociable mechanisms for implementing the Gestalt rule of continuity in CI over space and time.European Community’s Seventh Framework Programme (FP7/2007-2013) (Grant ID: 255577), Biotechnology and Biological Sciences Research Council (Grant IDs: D52199X , E027436), National Natural Science Foundation of China (Grant IDs: 31230030, 31571160, 91432102

Contour Integration over Time: Psychophysical and fMRI Evidence.

The brain integrates discrete but collinear stimuli to perceive global contours. Previous contour integration (CI) studies mainly focus on integration over space, and CI is attributed to either V1 long-range connections or contour processing in high-visual areas that top-down modulate V1 responses. Here, we show that CI also occurs over time in a design that minimizes the roles of V1 long-range interactions. We use tilted contours embedded in random orientation noise and moving horizontally behind a fixed vertical slit. Individual contour elements traveling up/down within the slit would be encoded over time by parallel, rather than aligned, V1 neurons. However, we find robust contour detection even when the slit permits only one viewable contour element. Similar to CI over space, CI over time also obeys the rule of collinearity. fMRI evidence shows that while CI over space engages visual areas as early as V1, CI over time mainly engages higher dorsal and ventral visual areas involved in shape processing, as well as posterior parietal regions involved in visual memory that can represent the orientation of temporally integrated contours. These results suggest at least partially dissociable mechanisms for implementing the Gestalt rule of continuity in CI over space and time

Domain evolution of BaTiO3 ultrathin films under electric field: a first-principles study

A first-principles-derived method is used to study the morphology and electric-field-induced evolution of stripe nanodomains in (001) BaTiO3 (BTO) ultrathin films, and to compare them with those in (001) Pb(Zr,Ti)O3 (PZT) ultrathin films. The BaTiO3 systems exhibit 180o periodic stripe domains at null electric field, as in PZT ultrathin films. However, the stripes alternate along [1-10] in BTO systems versus [010] in PZT systems, and no in-plane surface dipoles occur in BTO ultrathin films (unlike in PZT materials). Moreover, the evolution of the 180o stripe domains in the BaTiO3 systems, when applying and increasing an electric field along [001], involves four regions: Region I for which the magnitude of the down dipoles (i.e., those that are antiparallel to the electric field) is reduced, while the domain walls do not move; Region II in which some local down dipoles adjacent to domain walls switch their direction, resulting in zigzagged domain walls - with the overall stripe periodicity being unchanged; Region III in which nanobubbles are created, then contract along [110] and finally collapse; and Region IV which is associated with a single monodomain. Such evolution differs from that of PZT ultrathin films for which neither Region I nor zigzagged domain walls exist, and for which the bubbles contract along [100]. Discussion about such differences is provided.Comment: 19 pages, 4 figures, 27 references, submitted to Phys. Rev.

Project Report No. 67, A Whole-Stand Growth and Yield Model for Unmanaged Loblolly and Slash Pine Plantations in East Texas

The amount of forestland in east Texas has been estimated at 11.8 million acres, with approximately 2.5 million acres classified as pine plantations. The majority of these plantations are owned by forest industry (71 percent), while non-industrial private forest landowners represent the next largest shareholder (23 percent). Pine plantations are typically managed to produce timber, so information is needed to make informed management decisions. Growth is one piece of information that managers often rely upon in their decision-making process. The purpose of this paper is to develop an updated whole-stand growth and yield model for unmanaged loblolly and slash pine plantations in east Texas that improves upon the whole-stand model of Coble (2009). Specifically, this updated model includes a new equation to predict average stand diameter as well as an improved survival function

Identification of a latent pathogen on mulberry tree with a disease of mosaic dwarf

A disease on mulberries with the typical symptoms of mosaic and dwarf leaves was found in middle areas of China in 1980s. Presently, this disease became serious and spread out. Based on previous finding, we detected a viroid-like small molecular RNA in diseased mulberries tissues. In this paper, we further identified the pathogen of mulberry mosaic dwarf disease (MMDD) according to the Koch's postulates and reported the diagnostic method of the pathogen by using PCR with two sets of specific primers. The result might be helpful to control the disease extension

A modified stand table projection model for unmanaged loblolly and slash pine plantations in east Texas

Four methodologies to project future trees per acre by diameter class were compared to develop a new modified stand table projection growth model for unmanaged loblolly pine (Pinus taeda L.) and slash pine (Pinus elliottii Engelm.) plantations in East Texas. The new models were fit to 92,882 observations from 153 permanent plots located in loblolly pine plantations and 33,792 observations from 71 permanent plots located in slash pine plantations throughout East Texas. The new models were validated with 12,750 observations from 22 permanent plots and 3,724 observations from 9 permanent plots located in loblolly and slash pine plantations, respectively. The validation data were used to select between the four methodologies. The results indicated which of the new models produced the best results, based on error indexes calculated for trees per acre and basal area per acre at the stand table and diameter class levels across a range of projection lengths. We recommend that this new model be used by forest managers for projecting stand tables in East Texas loblolly and slash pine plantations. An example is also provided to show users how to use the new modified stand table projection model

Resin Flow in Loblolly and Shortleaf Pines Used by Red-Cockaded Woodpeckers

We measured resin flow in loblolly (Pinus taeda L.) and shortleaf (Pinus echinata Mill.) pines in stands used by red-cockaded woodpecker, Picoides borealis (Vieillot), in the Angelina and Davy Crockett National Forests in eastern Texas. We also measured resin flow in a mature loblolly pine stand not used by the woodpeckers. Resin flow varied by study area, species, and stand position. In woodpecker stands, pines experiencing low levels of competition seemed better able to tolerate the continual resin drainage associated with red-cockaded woodpecker resin well pecking. In the Angelina National Forest, all new cavity trees excavated during the study were on forest edges. In the non-woodpecker stand, edge trees had significantly better resin flow. These results indicate that the woodpeckers choose trees most likely to be good resin producers. They also indicate that silviculture in loblolly and shortleaf pine stands should favor edge and an open stand habit when red-cockaded woodpeckers are a major management consideration and that potential resin production can be measured in both cavity pines, and pines being considered for red-cockaded woodpecker introduction

Psychological Typhoon Eye in the 2008 Wenchuan Earthquake

BACKGROUND: On May 12, 2008, an earthquake measuring 8.0 on the Richter scale jolted Wenchuan, China, leading to 69,227 deaths and 374,643 injured, with 17,923 listed as missing as of Sept. 25, 2008, and shook the whole nation. We assessed the devastating effects on people's post-earthquake concern about safety and health. METHODOLOGY/PRINCIPAL FINDINGS: From June 4 to July 15, 2008, we surveyed a convenience sample of 2,262 adults on their post-earthquake concern about safety and health. Residents in non-devastated areas (Fujian and Hunan Provinces, and Beijing) and devastated areas (Sichuan and Gansu Provinces) responded to a questionnaire of 5 questions regarding safety measures, epidemic disease, medical workers, psychological workers, and medication. The ANOVAs showed a significant effect of residential devastation level on the estimated number of safety measures needed, the estimated probability of the outbreak of an epidemic, and the estimated number of medical and psychological workers needed (Ps<0.001). The post-earthquake concern decreased significantly as the level of residential devastation increased. Because of the similarity with the meteorological phenomenon of the eye of a typhoon, we dubbed these findings a "Psychological Typhoon Eye": the closer to the center of the devastated areas, the less the concern about safety and health a resident felt. CONCLUSIONS/SIGNIFICANCE: Contrary to common perception and ripple effect that the impact of an unfortunate event decays gradually as ripples spread outward from a center, a "Psychological Typhoon Eye" effect was observed where the post-earthquake concern was at its lowest level in the extremely devastated areas. The resultant findings may have implications for Chinese governmental strategies for putting "psychological comfort" into effect

Retrograde Interference in Perceptual Learning of a Peripheral Hyperacuity Task

Consolidation, a process that stabilizes memory trace after initial acquisition, has been studied for over a century. A number of studies have shown that a skill or memory must be consolidated after acquisition so that it becomes resistant to interference from new information. Previous research found that training on a peripheral 3-dot hyperacuity task could retrogradely interfere with earlier training on the same task but with a mirrored stimulus configuration. However, a recent study failed to replicate this finding. Here we address the controversy by replicating both patterns of results, however, under different experimental settings. We find that retrograde interference occurs when eye-movements are tightly controlled, using a gaze-contingent display, where the peripheral stimuli were only presented when subjects maintained fixation. On the other hand, no retrograde interference was found in a group of subjects who performed the task without this fixation control. Our results provide a plausible explanation of why divergent results were found for retrograde interference in perceptual learning on the 3-dot hyperacuity task and confirm that retrograde interference can occur in this type of low-level perceptual learning. Furthermore, our results demonstrate the importance of eye-movement controls in studies of perceptual learning in the peripheral visual field

High spatial resolution imaging of methane and other trace gases with the airborne Hyperspectral Thermal Emission Spectrometer (HyTES)

Currently large uncertainties exist associated with the attribution and quantification of fugitive emissions of criteria pollutants and greenhouse gases such as methane across large regions and key economic sectors. In this study, data from the airborne Hyperspectral Thermal Emission Spectrometer (HyTES) have been used to develop robust and reliable techniques for the detection and wide-area mapping of emission plumes of methane and other atmospheric trace gas species over challenging and diverse environmental conditions with high spatial resolution that permits direct attribution to sources. HyTES is a pushbroom imaging spectrometer with high spectral resolution (256 bands from 7.5 to 12 µm), wide swath (1&ndash;2 km), and high spatial resolution (∼ 2 m at 1 km altitude) that incorporates new thermal infrared (TIR) remote sensing technologies. In this study we introduce a hybrid clutter matched filter (CMF) and plume dilation algorithm applied to HyTES observations to efficiently detect and characterize the spatial structures of individual plumes of CH4, H2S, NH3, NO2, and SO2 emitters. The sensitivity and field of regard of HyTES allows rapid and frequent airborne surveys of large areas including facilities not readily accessible from the surface. The HyTES CMF algorithm produces plume intensity images of methane and other gases from strong emission sources. The combination of high spatial resolution and multi-species imaging capability provides source attribution in complex environments. The CMF-based detection of strong emission sources over large areas is a fast and powerful tool needed to focus on more computationally intensive retrieval algorithms to quantify emissions with error estimates, and is useful for expediting mitigation efforts and addressing critical science questions