253 research outputs found
A Values-Based Learning Model to Impact Maturational Change: The College Fraternity as Developmental Crucible
The period of late adolescence and early adulthood is a critical time during which individual identity is developed. One fraternity recently implemented a developmental process that facilitated identity maturation within its members by emphasizing self-awareness and reflection. Utilizing a learning model as the core component of all aspects of its programming, the fraternity conducted research to determine the impact of its learning model on the development of self-awareness. This article provides data from three years of implementation that documents significant increases in this critical developmental competency
Towards Integrative Systematics of Anthozoa (Cnidaria): Evolution of Form in the Order Zoanthidea
A decade of research inferring evolutionary relationships from nucleotide sequences has demonstrated a fundamental misconception of the evolution of form in Zoanthidea. Morphological features that define current taxa are plesiomorphic or homoplastic and do not circumscribe clades of species delineated by ecological and molecular characters. Although molecular data have been critical in exposing this deficiency, their parataxonomic application to Zoanthidea has created a barrier to comprehensive revision within the order. Species descriptions and higher taxon definitions based on nucleotide sequences isolate new taxa from the existing taxonomic system and restrict the application of novel systematics hypotheses to a fraction of the known diversity of taxa. This creates competing taxonomic systems that do not benefit from the knowledge contained in the opposing system. To enable the integration of modern molecular data with more than a century of morphological research, characters that can simultaneously span the parataxonomy barrier, existing taxonomic system and historical record must be identified. Here, we test the utility of morphological characters for integrative systematics by reviewing commonly described and novel morphological characters, assessing independence of character components and analysing character homoplasy and ancestral states on the most comprehensive molecular phylogeny available. The results indicate a rich diversity of form that span the full range of homoplasy values, including more than a dozen independent characters useful to systematics or differentiating closely related species. The least homoplasious characters include traditionally targeted (fifth mesenteries, marginal muscle arrangement, encircling sinus) and novel (fissure morphology, basal canals of the mesenteries) features. These analyses represent a first step in identifying characters necessary for reunification and revision of Zoanthidea systematics
Understanding the demand for REDD+ credits
REDD (Reducing emissions from deforestation and forest degradation), broadened to REDD+, has recently emerged as a potentially important component of the global policy mix to mitigate climate change. In this context, it has been the hope of policy-makers that private sector stakeholders will turn into novel and active actors in many of the different components of REDD+ such as forest conservation and many have expected them to play a central role in providing funding for forest protection. However, even as REDD+ credits have become increasingly available on the voluntary market - private sector stakeholders seem to have lost interest REDD+ carbon credits. In order to better understand possible models of private sector engagement in REDD+ in the future, this report analyzes the motivation of a sample of private sector stakeholders to engage in REDD+, the perception of the potential of REDD+, the critical obstacles to making REDD+ functional and finally how private sector actors perceive themselves as part of future REDD+ scenarios. Based on a range of qualitative engagements with a wide grouping of private sector actors, we find that few seem to expect a regulatory market for REDD+ to emerge and that credits from the voluntary market have to be more tailor-made to their specific needs (ranging from demands based on Corporate Social Responsibility, to portfolio diversification and hedging strategies against stranded assets). The carbon value alone is currently not sufficient for many private actors. For REDD+ to become more attractive for most surveyed private sector stakeholders, the main problem is the uncertainty about how REDD+ will be designed in the future, along with building understanding of the values, barriers and risks that accompany REDD+
Genarris: Random Generation of Molecular Crystal Structures and Fast Screening with a Harris Approximation
We present Genarris, a Python package that performs configuration space
screening for molecular crystals of rigid molecules by random sampling with
physical constraints. For fast energy evaluations Genarris employs a Harris
approximation, whereby the total density of a molecular crystal is constructed
via superposition of single molecule densities. Dispersion-inclusive density
functional theory (DFT) is then used for the Harris density without performing
a self-consistency cycle. Genarris uses machine learning for clustering, based
on a relative coordinate descriptor (RCD) developed specifically for molecular
crystals, which is shown to be robust in identifying packing motif similarity.
In addition to random structure generation, Genarris offers three workflows
based on different sequences of successive clustering and selection steps: the
"Rigorous" workflow is an exhaustive exploration of the potential energy
landscape, the "Energy" workflow produces a set of low energy structures, and
the "Diverse" workflow produces a maximally diverse set of structures. The
latter is recommended for generating initial populations for genetic
algorithms. Here, the implementation of Genarris is reported and its
application is demonstrated for three test cases
Oriented Thiophene-Extended Benzotrithiophene Covalent Organic Framework Thin Films: Directional Electrical Conductivity
The synthesis of covalent organic frameworks (COFs) based on a novel thiophene-extended benzotrithiophene (BTT) building block is described, which in combination with triazine-based amines (1,3,5-triazine-2,4,6-triyl)trianiline (TTA) or (1,3,5-triazine-2,4,6-triyl)tris(([1,1 '-biphenyl]-4-amine)) (TTTBA)) affords crystalline, and porous imine-linked COFs, BTT TTA and BTT TTTBA, with surface areas as high as 932 and 1200 m(2) g(-1), respectively. Oriented thin films are grown successfully on different substrates, as indicated by grazing incidence diffraction (GID). Room-temperature in-plane electrical conductivity of up to 10(-4) S m(-1) is measured for both COFs. Temperature-dependent electrical conductivity measurements indicate activation energies of approximate to 123.3 meV for BTT TTA and approximate to 137.5 meV for BTT TTTBA and trap-dominated charge transport via a hopping mechanism for both COFs. Moreover, conductive atomic force microscopy reveals directional and defect-dominated charge transport in the oriented BTT COF films with a strong preference for the in-plane direction within the molecular 2D-planes. Quantum mechanical calculations predict BTT TTTBA to conduct holes and electrons effectively in both in-plane and out-of-plane directions. In-plane, charge carrier transport is of hopping character where the triazine cores represent the barrier. Out-of-plane, a continuous charge-carrier pathway is calculated that is hampered by an imposed structural defect simulated by a rotated molecular COF layer
Very Extended X-ray and H-alpha Emission in M82: Implications for the Superwind Phenomenon
We discuss the properties and implications of a 3.7x0.9 kpc region of
spatially-coincident X-ray and H-alpha emission about 11.6 kpc to the north of
the galaxy M82 previously discussed by Devine and Bally (1999). The PSPC X-ray
spectrum is fit by thermal plasma (kT=0.80+-0.17 keV) absorbed by only the
Galactic foreground column density. We evaluate the relationship of the
X-ray/H-alpha ridge to the M82 superwind. The main properties of the X-ray
emission can all be explained as being due to shock-heating driven as the
superwind encounters a massive ionized cloud in the halo of M82. This encounter
drives a slow shock into the cloud, which contributes to the excitation of the
observed H-alpha emission. At the same time, a fast bow-shock develops in the
superwind just upstream of the cloud, and this produces the observed X-ray
emission. This interpretation would imply that the superwind has an outflow
speed of roughly 800 km/s, consistent with indirect estimates based on its
general X-ray properties and the kinematics of the inner kpc-scale region of
H-alpha filaments. The gas in the M82 ridge is roughly two orders-of-magnitude
hotter than the minimum "escape temperature" at this radius, so this gas will
not be retained by M82.
(abridged)Comment: 24 pages (latex), 3 figures (2 gif files and one postscript),
accepted for publication in Part 1 of The Astrophysical Journa
Greater neural responses to trajectory errors are associated with superior force field adaptation in older adults
Although age-related declines in cognitive, sensory and motor capacities are well documented, current evidence is mixed as to whether or not aging impairs sensorimotor adaptation to a novel dynamic environment. More importantly, the extent to which any deficits in sensorimotor adaptation are due to general impairments in neural plasticity, or impairments in the specific processes that drive adaptation is unclear. Here we investigated whether there are age-related differences in electrophysiological responses to reaching endpoint and trajectory errors caused by a novel force field, and whether markers of error processing relate to the ability of older adults to adapt their movements. Older and young adults (NâŻ=âŻ24/group, both sexes) performed 600 reaches to visual targets, and received audio-visual feedback about task success or failure after each trial. A velocity-dependent curl field pushed the hand to one side during each reach. We extracted ERPs time-locked to movement onset [kinematic error-related negativity (kERN)], and the presentation of success/failure feedback [feedback error-related negativity (fERN)]. At a group level, older adults did not differ from young adults in the rate or extent of sensorimotor adaptation, but EEG responses to both trajectory errors and task errors were reduced in the older group. Most interestingly, the amplitude of the kERN correlated with the rate and extent of sensorimotor adaptation in older adults. Thus, older adults with an impaired capacity for encoding kinematic trajectory errors also have compromised abilities to adapt their movements in a novel dynamic environment
Treatment with Helicobacter pylori-derived VacA attenuates allergic airway disease
BACKGROUND: Asthma is an incurable heterogeneous disease with variations in clinical and underlying immunological phenotype. New approaches could help to support existing therapy concepts. Neonatal infection of mice with Helicobacter pylori or administration of H. pylori-derived extracts or molecules after birth have been shown to prevent the development of allergic airway disease later in life. This study evaluated the potential therapeutic efficacy of H. pylori vacuolating cytotoxin A (VacA) in allergic airway inflammation and investigated the underlying immunological mechanisms for its actions.
METHODS: Murine models of allergic airway diseases, and murine and human in vitro models were used.
RESULTS: In both an acute model and a therapeutic house dust mite model of allergic airway disease, treatment with H. pylori-derived VacA reduced several asthma hallmarks, including airway hyperresponsiveness, inflammation and goblet cell metaplasia. Flow cytometry and ELISA analyses revealed induction of tolerogenic dendritic cells (DC) and FoxP3 positive regulatory T cells (Tregs), and a shift in the composition of allergen-specific immunoglobulins. Depletion of Tregs during treatment with VacA reversed treatment-mediated suppression of allergic airway disease. Human monocyte derived DCs (moDC) that were exposed to VacA induced Tregs in co-cultured naĂŻve autologous T cells, replicating key observations made in vivo.
CONCLUSION: H. pylori-derived VacA suppressed allergic airway inflammation via induction of Tregs in both allergic airway disease models. These data suggest that the immunomodulatory activity of VacA could potentially be exploited for the prevention and treatment of allergic airway disease
Tropical field stations yield high conservation return on investment
Conservation funding is currently limited; costâeffective conservation solutions are essential. We suggest that the thousands of field stations worldwide can play key roles at the frontline of biodiversity conservation and have high intrinsic value. We assessed field stationsâ conservation return on investment and explored the impact of COVIDâ19. We surveyed leaders of field stations across tropical regions that host primate research; 157 field stations in 56 countries responded. Respondents reported improved habitat quality and reduced hunting rates at over 80% of field stations and lower operational costs per km2 than protected areas, yet half of those surveyed have less funding now than in 2019. Spatial analyses support field station presence as reducing deforestation. These âearth observatoriesâ provide a high return on investment; we advocate for increased support of field station programs and for governments to support their vital conservation efforts by investing accordingly
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