Prevalence and predictors of sexual assault among a college sample.

OBJECTIVE: This study examined the prevalence and correlates of precollege, college-onset, and repeat sexual assault (SA) within a representative student sample. PARTICIPANTS: A representative sample of 7,603 students. METHODS: Incoming first-year students completed a survey about their exposure to broad SA prior to college, prior trauma, personality, relationships, and mental health. Broad SA was then reassessed each spring semester while enrolled. RESULTS: Nearly 20% of the sample reported experiencing broad SA, with women endorsing significantly higher rates compared with males. Prior victimization before coming to college was related to a greater risk of victimization in college, and there was no statistically significant difference between males and females who reported revictimization. Correlates of college-onset broad SA were found and are discussed. CONCLUSIONS: Given the need for SA intervention and prevention on college campuses, identification of factors potentially contributing to exposure within this population is essential.

Quantum superposition at the half-metre scale.

The quantum superposition principle allows massive particles to be delocalized over distant positions. Though quantum mechanics has proved adept at describing the microscopic world, quantum superposition runs counter to intuitive conceptions of reality and locality when extended to the macroscopic scale, as exemplified by the thought experiment of Schrödinger's cat. Matter-wave interferometers, which split and recombine wave packets in order to observe interference, provide a way to probe the superposition principle on macroscopic scales and explore the transition to classical physics. In such experiments, large wave-packet separation is impeded by the need for long interaction times and large momentum beam splitters, which cause susceptibility to dephasing and decoherence. Here we use light-pulse atom interferometry to realize quantum interference with wave packets separated by up to 54 centimetres on a timescale of 1 second. These results push quantum superposition into a new macroscopic regime, demonstrating that quantum superposition remains possible at the distances and timescales of everyday life. The sub-nanokelvin temperatures of the atoms and a compensation of transverse optical forces enable a large separation while maintaining an interference contrast of 28 per cent. In addition to testing the superposition principle in a new regime, large quantum superposition states are vital to exploring gravity with atom interferometers in greater detail. We anticipate that these states could be used to increase sensitivity in tests of the equivalence principle, measure the gravitational Aharonov-Bohm effect, and eventually detect gravitational waves and phase shifts associated with general relativity.

Spontaneous fast gamma activity in the septal hippocampal region correlates with spatial learning in humans.

Hippocampal neuronal populations exhibit multiple kinds of activity patterns, from the dominant theta rhythm during active exploration to high-frequency ripple-like activity during periods of relative inactivity. In animals, evidence is rapidly accruing that these high-frequency ripple activity patterns subserve retention of spatial learning performance. In a translational effort to address the possible function of offline hippocampal processes in humans, we measured spontaneous gamma activity during an awake rest period within a virtual spatial learning context. Whole-head magnetoencephalographic (MEG) recordings were taken while healthy participants (N=24) quietly rested (eyes open) between encoding and retrieval phases of a hippocampal-dependent virtual Morris water maze task. Results are that fast gamma activity (80-140 Hz) in the septal or posterior region of the hippocampus (bilaterally) was positively correlated across participants with subsequent within-session spatial learning rate. Fast gamma did not predict initial retrieval performance following rest, failing to provide evidence of a direct link between spontaneous high-frequency activity patterns during awake rest and consolidation of previous spatial memories. The findings nevertheless are consistent with a prospective role for offline human hippocampal processes in spatial learning and indicate that higher spontaneous gamma activity in the septal hippocampal region is related to faster updating of spatial knowledge in familiar virtual surroundings.

Site specific nematode management-development and success in cotton production in the United States.

Variability in edaphic factors such as clay content, organic matter, and nutrient availability within individual fields is a major obstacle confronting cotton producers. Adaptation of geospatial technologies such global positioning systems (GPS), yield monitors, autosteering, and the automated on-and-off technology required for site-specific nematicide application has provided growers with additional tools for managing nematodes. Multiple trials in several states were conducted to evaluate this technology in cotton. In a field infested with Meloidogyne spp., both shallow (0 to 0.3 m) and deep (0 to 0.91 m) apparent electrical conductivity (ECa) readings were highly correlated with sand content. Populations of Meloidogyne spp. were present when shallow and deep EC values were less than 30 and 90 mS/m, respectively. Across three years of trials in production fields in which verification strips (adjacent nematicide treated and untreated rows across all soil zones) were established to evaluate crop response to nematicide application, deep EC values from 27.4-m wide transects of verification strips were more predictive of yield response to application of 1,3-dichloropropene than were shallow EC values in one location and both ECa values equally effective at predicting responses at the second location. In 2006, yields from entire verification strips across three soil zones in four production fields showed that nematicide response was greatest in areas with the lowest EC values indicating highest content of sand. In 2008 in Ashley and Mississippi Counties, AR, nematicide treatment by soil zone resulted in 36% and 42% reductions in the amount of nematicide applied relative to whole-field application. In 2007 in Bamberg County, SC, there was a strong positive correlation between increasing population densities of Meloidogyne incognita and increasing sand content. Trials conducted during 2007 and 2009 in South Carolina against Hoplolaimus columbus showed a stepwise response to increasing rates of aldicarb in zone 1 but not in zones 2 and 3. Site-specific application of nematicides has been shown to be a viable option for producers as a potential management tool against several nematode pathogens of cotton.

Computational modeling of direct neuronal recruitment during intracortical microstimulation in somatosensory cortex.

OBJECTIVE: Electrical stimulation of cortical tissue could be used to deliver sensory information as part of a neuroprosthetic device, but current control of the location, resolution, quality, and intensity of sensations elicited by intracortical microstimulation (ICMS) remains inadequate for this purpose. One major obstacle to resolving this problem is the poor understanding of the neural activity induced by ICMS. Even with new imaging methods, quantifying the activity of many individual neurons within cortex is difficult. APPROACH: We used computational modeling to examine the response of somatosensory cortex to ICMS. We modeled the axonal arbors of eight distinct morphologies of interneurons and seven types of pyramidal neurons found in somatosensory cortex and identified their responses to extracellular stimulation. We then combined these axonal elements to form a multi-layered slab of simulated cortex and investigated the patterns of neural activity directly induced by ICMS. Specifically we estimated the number, location, and variety of neurons directly recruited by stimulation on a single penetrating microelectrode. MAIN RESULTS: The population of neurons activated by ICMS was dependent on both stimulation strength and the depth of the electrode within cortex. Strikingly, stimulation recruited interneurons and pyramidal neurons in very different patterns. Interneurons are primarily recruited within a dense, continuous region around the electrode, while pyramidal neurons were recruited in a sparse fashion both near the electrode and up to several millimeters away. Thus ICMS can lead to an unexpectedly complex spatial distribution of firing neurons. SIGNIFICANCE: These results lend new insights to the complexity and range of neural activity that can be induced by ICMS. This work also suggests mechanisms potentially responsible for the inconsistency and unnatural quality of sensations initiated by ICMS. Understanding these mechanisms will aid in the design of stimulation that can be used to generate effective sensory feedback for neuroprosthetic devices.

Depressed mood enhances anxiety to unpredictable threat.

BACKGROUND: Depression and anxiety disorders (ADs) are highly co-morbid, but the reason for this co-morbidity is unclear. One possibility is that they predispose one another. An informative way to examine interactions between disorders without the confounds present in patient populations is to manipulate the psychological processes thought to underlie the pathological states in healthy individuals. In this study we therefore asked whether a model of the sad mood in depression can enhance psychophysiological responses (startle) to a model of the anxiety in ADs. We predicted that sad mood would increase anxious anxiety-potentiated startle responses. METHOD: In a between-subjects design, participants (n=36) completed either a sad mood induction procedure (MIP; n=18) or a neutral MIP (n=18). Startle responses were assessed during short-duration predictable electric shock conditions (fear-potentiated startle) or long-duration unpredictable threat of shock conditions (anxiety-potentiated startle). RESULTS: Induced sadness enhanced anxiety- but not fear-potentiated startle. CONCLUSIONS: This study provides support for the hypothesis that sadness can increase anxious responding measured by the affective startle response. This, taken together with prior evidence that ADs can contribute to depression, provides initial experimental support for the proposition that ADs and depression are frequently co-morbid because they may be mutually reinforcing.

Vertical Distribution of Rotylenchulus reniformis in Cotton Fields.

The possible impact of Rotylenchulus reniformis below plow depth was evaluated by measuring the vertical distribution of R. reniformis and soil texture in 20 symptomatic fields on 17 farms across six states. The mean nematode population density per field, 0 to 122 cm deep, ranged from 0.4 to 63 nematodes/g soil, and in 15 fields more than half of the R. reniformis present were below 30.5 cm, which is the greatest depth usually plowed by farmers or sampled by consultants. In 11 fields measured, root density was greatest in the top 15 cm of soil; however, roots consistently penetrated 92 to 122 cm deep by midseason, and in five fields in Texas and Louisiana the ratio of nematodes to root-length density within soil increased with depth. Repeated sampling during the year in Texas indicated that up to 20% of the nematodes in soil below 60 cm in the fall survived the winter. Differences between Baermann funnel and sugar flotation extraction methods were not important when compared with field-to-field differences in nematode populations and field-specific vertical distribution patterns. The results support the interpretation that R. reniformis below plow depth can significantly impact diagnosis and treatment of cotton fields infested with R. reniformis.

Survey of crop losses in response to phytoparasitic nematodes in the United States for 1994.

Previous reports of crop losses to plant-parasitic nematodes have relied on published results of survey data based on certain commodities, including tobacco, peanuts, cotton, and soybean. Reports on crop-loss assessment by land-grant universities and many commodity groups generally are no longer available, with the exception of the University of Georgia, the Beltwide Cotton Conference, and selected groups concerned with soybean. The Society of Nematologists Extension Committee contacted extension personnel in 49 U.S. states for information on estimated crop losses caused by plant-parasitic nematodes in major crops for the year 1994. Included in this paper are survey results from 35 states on various crops including corn, cotton, soybean, peanut, wheat, rice, sugarcane, sorghum, tobacco, numerous vegetable crops, fruit and nut crops, and golf greens. The data are reported systematically by state and include the estimated loss, hectarage of production, source of information, nematode species or taxon when available, and crop value. The major genera of phytoparasitic nematodes reported to cause crop losses were Heterodera, Hoplolaimus, Meloidogyne, Pratylenchus, Rotylenchulus, and Xiphinema.

Interactions Between Calonectria crotalariae and Heterodera glycines on Soybean.

The interactions of Heterodera glycines at four egg inoculum levels (0, 100, 1,000, and 10,000 per pot) and three cyst levels (0, 100, and 200 per pot) and Calonectria crotalariae at 500, 5,000, and 50,000 microsclerotia per pot were evaluated on soybean. At the two lowest nematode egg levels, the presence of C. crotalariae did not affect nematode reproduction. At 10,000 eggs per pot, however, nematode reproduction was increased significantly at each microsclerotial level. The increase in nematode reproduction was stepwise at 500 and 5,000 microsclerotia per pot but declined at 50,000 microsclerotia per pot. Similar results were obtained when cysts rather than eggs were used as nematode inoculum. The nematode x fungus interaction significantly affected 60-day plant growth parameters of both Lee 74 and Centennial soybean. The nematode x fungus interaction was antagonistic to plant roots and significantly influenced root injury ratings. The presence of C. crotalariae in tissues of stock plants or plants used as race differentials did not alter the analysis of this population as race 3.

Influence of Calonectria crotalariae on Reproduction of Heterodera glycines on Soybean.

Calonectria crotalariae enhanced root penetration of Lee 74 (susceptible) and Centennial (resistant) soybeans by juveniles of race 3 of Heterodera glycines. Numbers of cysts in and on the roots of Lee 74 increased during the first 30 days in the presence of the fungus. Percentage of root infection by the fungus increased at 40 days in Lee 74 in the presence of the nematode. Numbers of cysts in soil at 80 and 120 days after inoculation with both organisms accounted for the significantly increased nematode population levels on Lee 74. In the presence of the fungus on the resistant cultivar, significantly increased levels of cysts were recovered from soil at 120 days. Fungus infection of Centennial roots also infected with the nematode increased from 58 to 86% at 120 days. An inoculum timing study in which Lee 74 was infested with the nematode and fungus individually, sequentially, and in combination at days 0 and 35 indicated that enhanced nematode reproduction was related more to early plant-fungus than to early plant-fungus-nematode interaction(s).

Permanent deficits in lordosis behavior in female rats with lesions of the ventromedial nucleus of the hypothalamus.

Bilateral lesions of the ventromedial nucleus of the hypothalamus (VMN) significantly attentuated lordosis behavior in the female rat. The degree of this deficit was significantly correlated with the amount of damage to the VMN. There was no improvement in lordosis performance even after an extended recovery period.