Assessment of Adolescents\u27 Knowledge of Suicide Warning Signs In Their Peers

The present study examined the knowledge adolescents have about suicide warning signs. Participants included 188 students (79% female and 21% male), 18 to 20 years old, from a Midwestern University. Participants anonymously completed an online survey. Results indicated that adolescents did not show knowledge of suicide warning signs. They also did not correctly identify suicide risk levels in three scenarios. Furthermore, direct exposure to suicide was not related to adolescents\u27 knowledge of suicide warning signs or risk factors; however, adolescents who looked up information about suicide online were better at identifying suicide warning signs. Finally, those who had a family or friend express thoughts of suicide had decreased suicidal ideation. Results, limitations, and implications of the study and future research directions are discussed

The Urotsa Bladder Cell Model For Heavy Metal Carcinogenesis: Characterization With Respect To The Role Of Beclin-1 And Sparc Expression

The development of bladder cancer is known to have a strong association with environmental toxins. This laboratory employs the human UROtsa cell line model to explore the relationship between As+3 and Cd+2 exposure and the development of urothelial cancer. The parental UROtsa cells and their As+3 and Cd+2 transformed counterparts have been used to define the mechanism of cell death (apoptosis and/or necrosis). A third mechanism of cell death, autophagy, has not yet been investigated. The hypothesis for the current study is that the autophagy pathway involving beclin-1plays a role in UROtsa cell death mechanisms. A combination of real time RT-PCR, western analysis, and immunohistochemistry showed that beclin-1 is expressed in the urothelium of normal human bladder, but large alterations in beclin-1 and its associated autophagy genes are not found in heavy metal induced bladder cancer cells. SPARC, a glycoprotein with counter adhesive properties, has the ability to modulate cell-cell and cell-matrix interactions. Microarray analysis indicated that SPARC gene expression was greatly decreased between parental and all transformed UROtsa cell lines. The hypothesis for this study is that a reduction in SPARC expression is necessary for a malignant phenotype to develop. SPARC expression was determined in human parental UROtsa cells, their Cd+2 and As+3 transformed counterparts, and in archival specimens of human bladder cancer using a combination of RT-PCR, western analysis, immunofluorescence localization, and immunohistochemical staining. This study showed that exposure to As+3 or Cd+2 greatly reduced SPARC expression in UROtsa cells. To further analyze SPARC expression, SPARC was stably transfected into select transformed UROtsa cell lines which were characterized based on growth rates, morphology, wound closure, migration, invasion, and tumorigenicity. Tumors generated by injection of the SPARC-transfected cell lines into nude mice, showed an absence of SPARC expression within the epithelial tumor component, but were positive for the transfected vector. This study suggests post-transcriptional down-regulation of SPARC expression in urothelial carcinoma cells within the mouse tumor environment. Overall, results from this study show that autophagy does not play a large cell death role within the UROtsa system however, down-regulation of SPARC expression does strongly correlate with the malignant phenotype

Growth of Planetary Embryos: Conserving Mass During Planet Formation in the Oligarchic Growth Stage

In order to fine-tune our current understanding of the formation of planets, we update the classic model of oligarchic growth to include mass conservation. In the early stages of planet formation, the protoplanetary disk contained only a swarm of planetesimals, rocky bodies with diameters of at most about 100 km, that collided together to form embryos greater than 1,000 km in diameter. Because planetesimals accrete, or accumulate, onto embryos, the surface mass density of the planetesimal swarm decreases with time. Here we describe surface mass density of the planetesimal swarm as the total initial surface mass density of the protoplanetary disk minus the surface mass density of the embryos. However, as the mass of the individual embryos increases, the average spacing between them must also change. Therefore, the parameter that is related to the characteristic spacing between embryos, b, must also change. We incorporate the changing eccentricity and surface mass density into a model that describes the growth of any given planetary embryo in the protoplanetary disk, which includes the new formulation for mass conservation. Finally, we test how the presence of a circum-embryo debris disk affects the growth rate of a planet. Because a debris disk in orbit about an embryo will increase the collisional cross-section of the planetary embryo, the time needed to fully grow the embryo decreases. The accelerated growth rate due to the circum-embryo disk holds implications for describing the formation of gas giant cores within the necessary timescale to capture the gas from the surrounding protoplanetary disk

MS

thesisPrevious studies have shown that verbalization, in the form of self-guided instruction, is an effective cognitive strategy used to enhance motor skill acquisition and motor performance. However, past research has not explicitly examined which aspects of motor output are affected (whether beneficially or deleteriously) by verbalization. In the current study, we conducted two separate experiments in which a total of 80 healthy participants, ages 18-27, completed a novel motor sequence learning task. Half of the participants in each Experiment were pretrained in the sequence using verbalization, while the other half was either trained motorically, or not trained at all. Rote memorization of verbal labels facilitated motor learning, motor control, performance speed, and set maintenance, but not motor planning. Potential underlying mechanisms as well as clinical implications are discussed

Doctor of Philosophy

dissertationIt is unknown if children with high-functioning autism (HFA) employ self-directed speech to guide motor sequencing and motor control, or if they can benefit from using self-directed speech when prompted to do so. Participants performed a three-movement sequence across three conditions: Natural Learning, Task-Congruent Verbalization (TCV), and Task-Incongruent Verbalization (TIV). TIV deleteriously impacted performance in the typically-developing group (TD; n= 22), and not the HFA group (n=21). TCV improved performance in both groups, but to a greater extent in the HFA group. These findings suggest that children with HFA do not initiate self-directed speech spontaneously, but can use language to guide behavior when prompted to do so

Archeota, Spring 2018

https://scholarworks.sjsu.edu/saasc_archeota/1007/thumbnail.jp

Conserving All the Pollinators: Variation in Probability of Pollen Transport among Insect Taxa

As concern about declining pollinator populations mounts, it is important to understand the range of insect taxa that provide pollination services. We use pollen transport information acquired over three years in two habitats at Badlands National Park, South Dakota, USA, to compare probabilities of pollen transport among insect taxa and between sexes of bees. Sampling was conducted on 1-ha plots, eight in sparse vegetation (May–October samples; N = 74 surveys) and 12 in wheatgrass prairie vegetation (June–July samples; N = 87 surveys). Insects contacting reproductive parts of flowers were netted, placed individually into tubes charged with ethyl acetate, then transferred to individual labeled glassine envelopes for transport to the lab. Pollen was removed from insect bodies with fuchsin jelly cubes which were then mounted on microscope slides for identification. The probability of taxa transporting only conspecific pollen (with respect to the plant species upon which it was collected), mixed pollen, only non-conspecific, or no pollen was estimated with multinomial logistic regression. Bees were the most commonly captured flower visitor and carried by far the most pollen (females \u3e10× as much as males), but they were most likely to carry mixed pollen loads. Flies, beetles, and wasps were also common flower visitors and beetles were most likely to carry only conspecific pollen. Ants and diurnal lepidopterans were unlikely to carry any pollen. Bees, beetles, flies, and wasps varied in the timing and habitat in which they were most likely to transport pollen, suggesting that all played a role in providing robust pollination services

Long-Term Dynamics of Leafy Spurge (\u3ci\u3eEuphorbia esula\u3c/i\u3e) and its Biocontrol Agent, Flea Beetles in the Genus Aphthona

Three flea beetle species (Aphthona spp.), first introduced into North America in 1988, have come to be regarded as effective biological control organisms for leafy spurge (Euphorbia esula). The black flea beetles (Aphthona lacertosa and A. czwalinae) in particular have been shown to cause reductions in leafy spurge stem counts in the northern Great Plains, while the brown flea beetle (A. nigriscutis) has persisted and spread, but has not been found to be as effective at controlling leafy spurge. The ability of black flea beetles to control leafy spurge in any given year, however, has been found to vary. To better understand the long-term effects of flea beetle herbivory on leafy spurge, we monitored stem counts of leafy spurge and numbers of black and brown flea beetles at three sites on two National Wildlife Refuges in east-central North Dakota, USA, from 1998 to 2006. Brown flea beetle numbers were observed to be negligible on these sites. Over the 9 years of the study, black flea beetles were seen to spread over the three study sites and leafy spurge stem counts declined substantially on two of the three sites. Even at low densities of spurge, black flea beetle populations persisted, a necessary prerequisite for long-term control. We used structural equation models (SEM) to assess the yearly effects of black flea beetles, soil texture, and refuge site on leafy spurge stem counts over this time period. We then used equations developed from the SEM analysis to explore flea beetle–leafy spurge dynamics over time, after controlling for soil texture and refuge. Yearly effect strength of black flea beetles on leafy spurge was found to be modest, largely owing to substantial spatial variability in control. However, simulation results based on prediction coefficients revealed leafy spurge to be highly responsive to increases in flea beetle populations on average

NATIVE AND EUROPEAN HAPLOTYPES OF \u3ci\u3ePHRAGMITES AUSTRALIS\u3c/i\u3e (COMMON REED) IN THE CENTRAL PLATTE RIVER, NEBRASKA

Phragmites australis (common reed) is known to have occurred along the Platte River historically, but recent rapid increases in both distribution and density have begun to impact habitat for migrating sandhill cranes and nesting piping plovers and least terns. Invasiveness in Phragmites has been associated with the incursion of a European genotype (haplotype M) in other areas; determining the genotype of Phragmites along the central Platte River has implications for proper management of the river system. In 2008 we sampled Phragmites patches along the central Platte River from Lexington to Chapman, NE, stratified by bridge segments, to determine the current distribution of haplotype E (native) and haplotype M genotypes. In addition, we did a retrospective analysis of historical Phragmites collections from the central Platte watershed (1902- 2006) at the Bessey Herbarium. Fresh tissue from the 2008 survey and dried tissue from the herbarium specimens were classified as haplotype M or E using the restriction fragment length polymorphism procedure. The European haplotype was predominant in the 2008 samples: only 14 Phragmites shoots were identified as native haplotype E; 224 were non-native haplotype M. The retrospective analysis revealed primarily native haplotype individuals. Only collections made in Lancaster County, near Lincoln, NE, were haplotype M, and the earliest of these was collected in 1973

Factors affecting post-control reinvasion by seed of an invasive species, \u3ci\u3ePhragmites australis\u3c/i\u3e, in the central Platte River, Nebraska

Invasive plants, such as Phragmites australis, can profoundly affect channel environments of large rivers by stabilizing sediments and altering water flows. Invasive plant removal is considered necessary where restoration of dynamic channels is needed to provide critical habitat for species of conservation concern. However, these programs are widely reported to be inefficient. Post-control reinvasion is frequent, suggesting increased attention is needed to prevent seed regeneration. To develop more effective responses to this invader in the Central Platte River (Nebraska,USA), we investigated several aspects of Phragmites seed ecology potentially linked to post-control reinvasion, in comparison to other common species: extent of viable seed production, importance of water transport, and regeneration responses to hydrology. We observed that although Phragmites seed does not mature until very late in the ice-free season, populations produce significant amounts of viable seed (\u3e50 %of filled seed). Most seed transported via water in the Platte River are invasive perennial species, although Phragmites abundances are much lower than species such as Lythrum salicaria, Cyperus esculentus and Phalaris arundinacea. Seed regeneration of Phragmites varies greatly depending on hydrology, especially timing of water level changes. Flood events coinciding with the beginning of seedling emergence reduced establishment by as much as 59 % compared to flood events that occurred a few weeks later. Results of these investigations suggest that prevention of seed set (i.e., by removal of flowering culms) should be a priority in vegetation stands not being treated annually. After seeds are in the seedbank, preventing reinvasion using prescribed flooding has a low chance of success given that Phragmites can regenerate in a wide variety of hydrologic microsites