Current and potential distributions of three non-native invasive plants in the contiguous USA

Biological invasions pose a serious threat to biodiversity, but monitoring for invasive species is time consuming and costly. Understanding where species have the potential to invade enables land managers to focus monitoring efforts. In this paper, we compared two simple types of models to predict the potential distributions of three non-native invasive plants (Geranium robertianum, Hedera spp., and Ilex aquifolium) in the contiguous USA. We developed models based on the climatic requirements of the species as reported in the literature (literature-based) and simple climate envelope models based on the climate where the species already occur (observation-based). We then compared the results of these models with the current species distributions. Most models accurately predicted occurrences, but overall accuracy was often low because these species have not yet spread throughout their potential ranges. However, literature-based models for Geranium and observation-based models for Ilex illustrated potential problems with the methodology. Although neither model type produced accurate predictions in all cases, comparing the two methods with each other and with the current species distributions provided rough estimates of the potential habitat for each species. More importantly, this methodology raised specific questions for further research to increase our understanding of invasion patterns of these species. Although these types of models do not replace more rigorous modeling techniques, we suggest that this methodology can be an important early step in understanding the potential distributions of non-native species and can allow managers of natural areas to be aware of potential invaders and implement early detection

Same-Sex Focus in the Visual Attention of Heterosexual Women: An Investigation of Potential Explanations

When simultaneously presented with male and female erotic visual stimuli, heterosexual women have a significantly less category-specific pattern of visual attention, wherein they spend much more time viewing same sex stimuli than do men. Heterosexual men, on the other hand, have a much more category-specific pattern of visual attention, allocating nearly all of their visual attention to the female stimuli. The present study investigated several proposed explanations for women’s more diffuse visual attention patterns: that heterosexual women may find some arousal value in viewing erotic female images given their greater sexual fluidity/erotic plasticity in comparison to men, that women may be engaging in social comparison with the same-sex images to an extent that men do not, that women may have a more erotic self-focus in comparison to men that translates into visual attention to other women, and/or that women may be empathizing and projectively identifying with the women in the images, given that women appear to have a greater empathic orientation . To test these potential explanations, 117 heterosexual women viewed 12 split-screen slides, each of which featured paired erotic photos of a nude man and a nude woman on each side of the screen, while their gaze patterns were tracked using an eye-tracker. Participants then completed a series of measures designed to assess individual variability on erotic fluidity, tendency toward appearance-based social comparison, erotic self-focus, and empathy orientation. Correlational and regression analyses were used to explore the relationship between women’s visual attention patterns and their endorsements of the afore-mentioned constructs. Participants’ endorsement of greater cognitive/affective arousal toward women (i.e., erotic fluidity) was significantly related to greater visual attention on the female, compared to male, images. It thus appears that, at the level of visual attention, self-identified heterosexual women who are more erotically fluid are more likely to focus on erotic images of nude women. These results support the contention that the visual attention to the female images might be arousal-based and it converges with more recent data on women’s genital arousal patterns to visual sexual stimuli. Social comparison, erotic self-focus, and empathy orientation, as measured in this study, were not significantly related to visual attention patterns. Interpretations of these results, in light of this study’s limitations, are discussed, as are future directions for this line of research

Formation of contacts between doped carbon nanotubes and aluminum electrodes

A theoretical study of the a semiconducting carbon nanotube (CNT) bonding to an aluminum electrode is presented using density functional theory to determine the electronic structure, and charge transport across the junction is studied using non-equilibrium Green's functions. The properties of CNT-metal junctions are of interest for optimizing metal-semiconductor junctions for Schottky barrier transistors and for the formation of Ohmic contacts for nanoelectronics. We first consider the properties of an undoped (16,0) CNT bonded to an aluminum electrode, including an analysis of metal induced gap states and examination of the surface dipole. The junction is then modified by introduction of substitutional dopants into the CNT using nitrogen and boron to form n- and p-type semiconductors, respectively, and the resulting impact of the doping on current transport across the junctions is calculated. As an alternative doping strategy, tetrathiafulvalene is introduced endohedrally and found to act as an n-type dopant in agreement with previous experimental studies. From electron transmission and current voltage characteristics, it is found that the doped junctions can be engineered to have much lower onset resistances relative to the undoped junction. It is found that the current-voltage characteristics display increased resistance for larger forward and reverse biases: For one polarity, the resistance increase is associated with the introduction of the CNT band gap into the voltage bias window, whereas for the opposing voltage polarity, the resistance increase is due to large charge carrier-substitutional dopant scattering. For the case of the endohedral doping scheme, it is found that the carrier-dopant scattering is effectively absent. (C) 2013 AIP Publishing LLC

An indigenous approach to explore health-related experiences among Māori parents: the Pukapuka Hauora asthma study.

Published onlineJournal ArticleResearch Support, Non-U.S. Gov'tBACKGROUND: The prevalence of asthma for Indigenous New Zealand Māori is amongst the highest in the world. Recent evidence shows ethnic differences in asthma symptom prevalence in New Zealand have widened, with asthma symptoms and hospitalisation rates consistently higher for Māori across all age-groups, especially children and adolescents. This paper: outlines our qualitative, longitudinal research exploring the practical issues Māori children and their families face trying to achieve optimum asthma outcomes; details the research methods used within this study; and discusses the process evaluation findings of the features that made this approach successful in engaging and retaining participants in the study. METHODS: Thirty-two Māori families were recruited using a Kaupapa Māori (Māori way) Research approach. Each participated in a series of four in-depth interviews that were carried out at seasonal intervals over the course of one year. Families also took part in an interviewer-administered questionnaire and participated in a Photovoice exercise. All interviews were digitally recorded, transcribed verbatim and independently coded by two researchers. The research team then conducted the analysis and theme development. The questionnaires were analysed separately, with explanations for findings explored within the qualitative data. RESULTS: The methodology produced a 100 percent retention rate of the participating families over the course of the follow-up. This was attributed to the research collaboration, the respectful research relationships established with families, and the families' judgement that the methods used enabled them to tell their stories. The acceptability of the methodology will add to the validity and trustworthiness of the findings. CONCLUSION: Given the extent and persistence of ethnic disparities in childhood asthma management, it is imperative that an indigenous approach be taken to understanding the core issues facing Māori families. By conducting community-partnership research underpinned by an indigenous methodology, and employing a range of appropriate methods, we have successfully recruited and retained a cohort of Māori families with experiences of childhood asthma. We aim to make their voices heard in order to develop a series of culturally relevant interventions aimed at remediating these disparities.Health Research Council of New ZealandNIH

Electron transport properties of sub-3-nm diameter copper nanowires

Density functional theory and density functional tight-binding are applied to model electron transport in copper nanowires of approximately 1 nm and 3 nm diameters with varying crystal orientation and surface termination. The copper nanowires studied are found to be metallic irrespective of diameter, crystal orientation and/or surface termination. Electron transmission is highly dependent on crystal orientation and surface termination. Nanowires oriented along the [110] crystallographic axis consistently exhibit the highest electron transmission while surface oxidized nanowires show significantly reduced electron transmission compared to unterminated nanowires. Transmission per unit area is calculated in each case, for a given crystal orientation we find that this value decreases with diameter for unterminated nanowires but is largely unaffected by diameter in surface oxidized nanowires for the size regime considered. Transmission pathway plots show that transmission is larger at the surface of unterminated nanowires than inside the nanowire and that transmission at the nanowire surface is significantly reduced by surface oxidation. Finally, we present a simple model which explains the transport per unit area dependence on diameter based on transmission pathways results

Calcium-Dependent But Action Potential-Independent BCM-Like Metaplasticity in the Hippocampus

The Bienenstock, Cooper and Munro (BCM) computational model, which incorporates a metaplastic sliding threshold for LTP induction, accounts well for experience-dependent changes in synaptic plasticity in the visual cortex. BCM-like metaplasticity over a shorter timescale has also been observed in the hippocampus, thus providing a tractable experimental preparation for testing specific predictions of the model. Here, using extracellular and intracellular electrophysiological recordings from acute rat hippocampal slices, we tested the critical BCM predictions (1) that high levels of synaptic activation will induce a metaplastic state that spreads across dendritic compartments, and (2) that postsynaptic cell-firing is the critical trigger for inducing that state. In support of the first premise, high-frequency priming stimulation inhibited subsequent long-term potentiation and facilitated subsequent long-term depression at synapses quiescent during priming, including those located in a dendritic compartment different to that of the primed pathway. These effects were not dependent on changes in synaptic inhibition or NMDA/ metabotropic glutamate receptor function. However, in contrast to the BCM prediction, somatic action potentials during priming were neither necessary nor sufficient to induce the metaplasticity effect. Instead, in broad agreement with derivatives of the BCM model, calcium as released from intracellular stores and triggered byM1 muscarinic acetylcholine receptor activation was critical for altering subsequent synapticplasticity. These results indicate that synaptic plasticity in stratum radiatum of CA1 can be homeostatically regulated by the cell-wide history of synaptic activity through a calcium-dependent but action potential-independent mechanis

The Pandemic Leadership Model: A Study of Medical Student Values During COVID-19

Background: Leadership training in medical school continues to grow. Little information exists to guide leadership program development. Concurrently, the COVID-19 pandemic provides a real-world crucible of leadership, allowing insight into qualities and characteristics medical students value. We aim to determine what students value in leadership during a pandemic and the implicit framework students use. Methods: We conducted a cross-sectional, qualitative study using a five-item novel survey instrument developed by a consensus group of experts from family medicine, leadership development, medical education, and survey research to elicit student perceptions of effective and ineffective leadership qualities and examples during the COVID-19 pandemic at the University of Michigan Medical School. We used thematic analysis to identify overarching themes to build a model of leadership integrated with existing theory. Results: 162 students participated across all years of medical school. We identified themes of Communication, Other-Orientation, Personal Characteristics, Decisive Action, and Use of Information. These five themes were then built into the model of Pandemic Leadership within the context of complexity leadership theory and collective leadership theory. This model represents qualities and characteristics students value in good leaders during a crisis. Conclusion: This study is unique in its focus on student perceptions of leadership qualities during a real-world laboratory for leadership. We hope that this information, along with the pandemic leadership model, can serve as the first step toward relevant leadership training programs in medical education. Leadership training programs in medical education would likely benefit from grounding in the student values identified by this study

Neural tube derived Wnt signals cooperate with FGF signaling in the formation and differentiation of the trigeminal placodes

BACKGROUND: Neurogenic placodes are focal thickenings of the embryonic ectoderm that form in the vertebrate head. It is within these structures that the precursors of the majority of the sensory neurons of the cranial ganglia are specified. The trigeminal placodes, the ophthalmic and maxillomandibular, form close to the midbrain-hindbrain boundary and many lines of evidence have shown that signals emanating from this level of the neuraxis are important for the development of the ophthalmic placode. RESULTS: Here, we provide the first evidence that both the ophthalmic and maxillomandibular placodes form under the influence of isthmic Wnt and FGF signals. Activated Wnt signals direct development of the Pax3 expressing ophthalmic placodal field and induce premature differentiation of both the ophthalmic and the maxillomandibular placodes. Similarly, overexpression of Fgf8 directs premature differentiation of the trigeminal placodes. Wnt signals require FGF receptor activity to initiate Pax3 expression and, subsequently, the expression of neural markers, such as Brn3a, within the cranial ectoderm. Furthermore, fibroblast growth factor signaling via the mitogen activated protein kinase pathway is required to maintain early neuronal differentiation within the trigeminal placodes. CONCLUSION: We demonstrate the identity of inductive signals that are necessary for trigeminal ganglion formation. This is the first report that describes how isthmic derived Wnt signals act in concert with fibroblast growth factor signaling. Together, both are necessary and sufficient for the establishment and differentiation of the ophthalmic and maxillomandibular placodes and, consequently, the trigeminal ganglion

Neural tube derived Wnt signals cooperate with FGF signaling in the formation and differentiation of the trigeminal placodes

<p>Abstract</p> <p>Background</p> <p>Neurogenic placodes are focal thickenings of the embryonic ectoderm that form in the vertebrate head. It is within these structures that the precursors of the majority of the sensory neurons of the cranial ganglia are specified. The trigeminal placodes, the ophthalmic and maxillomandibular, form close to the midbrain-hindbrain boundary and many lines of evidence have shown that signals emanating from this level of the neuraxis are important for the development of the ophthalmic placode.</p> <p>Results</p> <p>Here, we provide the first evidence that both the ophthalmic and maxillomandibular placodes form under the influence of isthmic Wnt and FGF signals. Activated Wnt signals direct development of the <it>Pax3 </it>expressing ophthalmic placodal field and induce premature differentiation of both the ophthalmic and the maxillomandibular placodes. Similarly, overexpression of <it>Fgf8 </it>directs premature differentiation of the trigeminal placodes. Wnt signals require FGF receptor activity to initiate <it>Pax3 </it>expression and, subsequently, the expression of neural markers, such as <it>Brn3a</it>, within the cranial ectoderm. Furthermore, fibroblast growth factor signaling via the mitogen activated protein kinase pathway is required to maintain early neuronal differentiation within the trigeminal placodes.</p> <p>Conclusion</p> <p>We demonstrate the identity of inductive signals that are necessary for trigeminal ganglion formation. This is the first report that describes how isthmic derived Wnt signals act in concert with fibroblast growth factor signaling. Together, both are necessary and sufficient for the establishment and differentiation of the ophthalmic and maxillomandibular placodes and, consequently, the trigeminal ganglion.</p

Comparative Analysis of Zoning of Food Retail and Urban Agriculture for Richmond, Virginia

This research partnership between local public health practitioners and urban food systems scholars suggests improvements to City of Richmond, Virginia’s zoning code related to food retail and urban agriculture by drawing inspiration from other American central cities. The authors created an empirical process to identify potential sister cities to Richmond as a source for high quality comparative examples. Next, the authors then engaged in a non-empirical, purposive process of identifying potential zoning code improvements from both identified sister cities, as well as other communities. Time and capacity constraints dictated the non-empirical nature of this search. Recommendations for improvement to Richmond’s zoning code are included. Local government officials and potential urban food entrepreneurs of jurisdictions with comparable characteristics to the City of Richmond could benefit from this analysis