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There is a limited understanding about the ecological mechanisms that enable certain plant species to become successful invaders of natural areas. This study was conducted to determine the soil and landscape characteristics that correlate with invasion of Chinese privet (CHP), and to develop a model to predict the probability of CHP invasion in Piedmont forests. A landscape ecosystem classification (LEC) system—based on the percentage of clay in the B horizon, depth to maximum clay (cm), exposure, terrain shape, and aspect (degrees)—was used to determine the soil moisture characteristics of invaded and uninvaded plots. Additional measurements included the cover classes of CHP and other species, litter depth (cm), slope (degrees), overstory basal area (m2 ha−1), and soil chemical properties. CHP invasion was negatively correlated with overstory basal area and slope and positively with litter depth and pH. A stepwise logistic regression model containing these four variables was highly sensitive, with an overall accuracy of 78%. Given the accuracy of this model, we propose that it can be used to calculate the probability of invasion in a given area, provided that some basic, readily obtainable site characteristics are known.
This paper examines the dynamic coupling between a sloshing fluid and the motion of the vessel containing the fluid. A mechanism is identified that leads to an energy exchange between the vessel dynamics and fluid motion. It is based on a 1:1 resonance in the linearized equations, but nonlinearity is essential for the energy transfer. For definiteness, the theory is developed for Cooker’s pendulous sloshing experiment. The vessel has a rectangular cross-section, is partially filled with a fluid and is suspended by two cables. A nonlinear normal form is derived close to an internal 1:1 resonance, with the energy transfer manifested by a heteroclinic connection, which connects the purely symmetric sloshing modes to the purely antisymmetric sloshing modes. Parameter values where this pure energy transfer occurs are identified. In practice, this energy transfer can lead to sloshing-induced destabilization of fluid-carrying vessels.
Titanium (IV) oxide, TiO2, has been the object of intense scrutiny for energy applications. TiO2 is inexpensive, non-toxic, and has excellent corrosion resistance when exposed to electrolytes. A major drawback preventing the widespread use TiO2 for photolysis is its relatively large band gap of ∼3eV. Only light with wavelengths shorter than 400 nm, which is in the ultraviolet portion of the spectrum, has sufficient energy to be absorbed. Less than 14 percent of the solar irradiation reaching the earth’s surface has energy exceeding this band gap. Adding dopants such as transition metals has long been used to reduce the gap and increase photocatalytic activity by accessing the visible part of the solar spectrum. The degree to which the band gap is reduced using transition metals depends in part on the overlap of the d-orbitals of the transition metals with the oxygen p-orbitals. Therefore, doping with anions such as nitrogen to modify the cation-anion orbital overlap is another approach to reduce the gap. Recent studies suggest that using a combination of transition metals and nitrogen as dopants is more effective at introducing intermediate states within the band gap, effectively narrowing it. Here we report the synthesis of mesoporous TiO2 spheres, co-doped with transition metals and nitrogen that exhibit a nearly flat absorbance response across the visible spectrum extending into the near infrared.
Objectives: Schizophrenia imposes a great burden on society, and while evaluation should play an important role in informing society's efforts to alleviate these burdens, it is unclear what “endpoints” should be chosen as the objective of such analyses. The objectives of the study were to elicit endpoints directly from patients with schizophrenia, to ascertain whether patients are sufficiently cognoscente to express what endpoints are and are not important to them and to rank the relevant endpoints.
Methods: We applied principles of patient-centered health technology assessment to identify and value endpoints from the patient's perspective. Focus groups were conducted to elicit endpoints, using interpretive phenomalogical analysis (IPA) to guide the collection, analysis and interpretation of data. Patient interviews were subsequently used to elicit patient preference over endpoints. Respondents were presented with cards outlining the endpoints and asked to remove irrelevant cards. They where then asked to identify and rank their five most relevant endpoints in order of importance. Interviews were recorded for the purposed of triangulation, and data was analyzed using descriptive statistics. Patients were recruited from five geographically diverse cities in Germany. Eligibility required a diagnosis of schizophrenia by a physician and treatment with an antipsychotic medication for at least one year. Respondents were excluded if they were experiencing an acute episode.
Results: Thirteen endpoints emerged as important from the focus groups spanning side-effects, functional status, processes of care and clinical outcomes. Respondents could clearly identify relevant and irrelevant endpoints, and rank which factors were important to them. Triangulation between field notes of the ranking exercise and recordings confirmed that rankings were not arbitrary, but justified from the respondents' point of view.
Conclusions: Patients with schizophrenia can express preferences over endpoints. Our results show that qualitative methods such as IPA can be used to identify factors, but ranking exercises provide a more robust method for ranking the importance of endpoints. Future research involving patients with schizophrenia ranking outcomes is needed to identify variations across patients and methods such as conjoint analysis could prove beneficial in identifying acceptable tradeoffs across endpoints.
Executive functions are highly sensitive to the effects of aging and
other conditions affecting frontal lobe function. Yet there are few
validated interventions specifically designed to address executive
functions, and, to our knowledge, none validated in a healthy aging
sample. As part of a large-scale cognitive rehabilitation randomized trial
in 49 healthy older adults, a modified Goal Management Training program
was included to address the real-life deficits caused by executive
dysfunction. This program emphasized periodic suspension of ongoing
activity to establish goal hierarchies and monitor behavioral output.
Tabletop simulated real-life tasks (SRLTs) were developed to measure the
processes targeted by this intervention. Participants were randomized to
two groups, one of which received the intervention immediately and the
other of which was wait-listed prior to rehabilitation. Results indicated
improvements in SRLT performance and self-rated executive deficits
coinciding with the training in both groups. These gains were maintained
at long-term follow-up. Future research will assess the specificity of
these effects in patient groups (JINS, 2007, 13,
This study reports the effects of a 12-week multimodular cognitive
rehabilitation training program on memory performance in two groups of
older adults. In the Memory Training module, participants were instructed
on the nature of memory and how to improve memory performance; internal
and external strategies were described and practiced over the training
sessions. Memory performance was assessed by four tests: Alpha Span,
Brown-Peterson, Hopkins Verbal Learning Test − Revised (HVLT-R), and
Logical Stories. One group received training on entry into the study
(Early Training Group, ETG), the other after a 3-month delay (Late
Training Group, LTG). The results showed no training-related improvement
in working memory (Alpha Span), primary memory (Brown-Peterson, HVLT-R),
or recognition memory (HVLT-R). While the most direct analyses of a
training effect (analyses of covariance) rarely demonstrated significant
effects, exploratory analyses provided some evidence for a training
benefit in several measures of secondary memory (Logical Stories; HVLT-R)
and strategic processing (Brown-Peterson; Logical Stories; HVLT-R).
Positive results were largely restricted to the ETG, possibly because the
LTG lost motivation as a consequence of their delayed training. The
results need to be treated with caution, but are promising for the
rehabilitation of memory functioning in older adults (JINS, 2007,
In this study, we report changes in psychosocial function in two
groups of older adults that participated in the experimental trial of our
cognitive rehabilitation program. The results, based on tests that
measured a range of psychosocial attributes, showed that, following
training, participants improved in terms of overall well-being, as well as
in specific areas that included perceived happiness, coping strategies,
and quality of life. An important finding was that improvements were also
observed in long-term follow-up testing. Both groups benefited from
training, but the effect was greater in the group that received training
before undergoing a control procedure. The results, which show that the
benefits of our rehabilitation program extend into the psychosocial
domain, underscore the potentially important relationship between
psychosocial factors and cognitive performance in older adults.
(JINS, 2007, 13, 153–165.)
A generalization of criticality – called secondary criticality – is introduced and applied to finite-amplitude Stokes waves. The theory shows that secondary criticality signals a bifurcation to a class of steady dark solitary waves which are biasymptotic to a Stokes wave with a phase jump in between, and synchronized with the Stokes wave. We find the that the bifurcation to these new solitary waves – from Stokes gravity waves in shallow water – is pervasive, even at low amplitude. The theory proceeds by generalizing concepts from hydraulics: three additional functionals are introduced which represent non-uniformity and extend the familiar mass flux, total head and flow force, the most important of which is the wave action flux. The theory works because the hydraulic quantities can be related to the governing equations in a precise way using the multi-symplectic Hamiltonian formulation of water waves. In this setting, uniform flows and Stokes waves coupled to a uniform flow are relative equilibria which have an attendant geometric theory using symmetry and conservation laws. A flow is then ‘critical’ if the relative equilibrium representation is degenerate. By characterizing successively non-uniform flows and unsteady flows as relative equilibria, a generalization of criticality is immediate. Recent results on the local nonlinear behaviour near a degenerate relative equilibrium are used to predict all the qualitative properties of the bifurcating dark solitary waves, including the phase shift. The theory of secondary criticality provides new insight into unsteady waves in shallow water as well. A new interpretation of the Benjamin–Feir instability from the viewpoint of hydraulics, and the connection with the creation of unsteady dark solitary waves, is given in Part 2.
The theory for criticality presented in Part 1 is extended to the unsteady problem, and a new formulation of the Benjamin–Feir instability for Stokes waves in finite depth coupled to a mean flow, which takes the criticality matrix as an organizing centre, is presented. The generation of unsteady dark solitary waves at points of stability changes and their connection with the steady dark solitary waves of Part 1 are also discussed.
Case-based reasoning (CBR) is an approach to problem solving that emphasizes the role of prior experience during future problem solving (i.e., new problems are solved by reusing and if necessary adapting the solutions to similar problems that were solved in the past). It has enjoyed considerable success in a wide variety of problem solving tasks and domains. Following a brief overview of the traditional problem-solving cycle in CBR, we examine the cognitive science foundations of CBR and its relationship to analogical reasoning. We then review a representative selection of CBR research in the past few decades on aspects of retrieval, reuse, revision and retention.
We have investigated the stellar kinematics of two brightest cluster galaxies (BCGs) to large distances from the cluster centre. In both galaxies, the velocity dispersion rises with radius. Orbital anisotropy is ruled out as the cause and we conclude that the kinematics in the outer parts of BCGs are dark matter dominated. This result contrasts with the current problem for intermediate luminosity ellipticals, which appear to have less dark matter than predicted by CDM. Combining the present results with our previous work, the fraction of BCGs with outwardly rising dispersions ($\sim60\%$) is much higher than that found previously ($\sim7\%$) from the inner parts of BCGs. We argue that this phenomenon may be more common than previously thought. The agreement with radial trends expected for a smooth galaxy/cluster transition, and the lack of dependence on cD/BCG dominance and cluster environment, suggest that the outwardly rising dispersion is a genuine response of the stars to the underlying cluster potential. There is evidence that BCG in Abell 2063 is not at the centre of the cluster potential.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html
A main topic at this meeting is how galaxies are affected when they enter for the first time the cluster environment from the outskirts. Most of the times we are forced to infer the environmental effects indirectly, relying on systematic variations of galaxy properties with environment, but there aren't many examples of direct observations able to unveil ongoing transformations, and the corresponding mechanism producing it. We present a case in which it is possible to identify the cluster environment, and in particular the intracluster medium and the recent infall history of galaxies onto the cluster, as the cause for a recent, abrupt change in the evolutionary history of galaxies.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html
Here we present a short progress report of a comprehensive search for variability in the globular cluster 47 Tucanae. Using the MSSSO 40” telescope and a combined V+R filter, we are searching for variability across a 52×52' field centered on the cluster. The main aim is to search for transiting ‘Hot Jupiter’ planets in this cluster, the results of which are still being produced, but a natural side product is a deep catalogue of variable stars within the cluster field. The experiment samples the whole of the cluster (except the inner 5'), thus probing the uncrowded outer regions where the stellar densities are lower, increasing the prospects for the survivability of planetary systems. Half of the currently identified variable stars are new discoveries. We have data for 36,000 stars with masses similar to that of the Sun for the main transit search.
We present an investigation of the halo dynamics of M31 using planetary nebulae velocities. We have performed on-band [OIII] and off-band continuum imaging for a 3.6 square degree area centred on M31 and follow-up spectroscopy for over 600 planetary nebulae candidates. In the future the halo mass will be measured and the mass distribution and velocity anisotropy will be constrained as a function of radius.