Strong correlation effects in single-wall carbon nanotubes

We present an overview of strong correlations in single-wall carbon nanotubes, and an introduction to the techniques used to study them theoretically. We concentrate on zigzag nanotubes, although universality dictates that much ofthe theory can also be applied to armchair or chiral nanotubes. We show how interaction effects lead to exotic low energy properties and discuss future directions for studies on correlation effects in nanotubes

Evaluation of the effect of hedgerow intercropping using Leucaena leucocephala and fertilizer application on growth and yield of garden eggs (Solanum melongena)

Field trials were conducted in Ghana to assess the effect of applying Leucaena prunings as mulch and N.P.K., 15-15-15 compound fertilizer on the growth and yield of garden eggs (Solanum melongena) during the 1993 minor and 1994 major cropping seasons. The crop was grown with or without Leucaena mulch as well as 0 kg/ha, 180 kg/ha and 360 kg/ha rates of fertilizer. The crop responded very well to the 15-15-15 compound fertilizer used, since plants without fertilizer had significantly reduced height; more days to flowering, fruiting and harvesting and produced yields far below the potential yield levels of the crop. In both seasons, applying the Leucaena mulch increased the mean yield by 21 percent over the no mulch treatments. Economic analysis of the various treatments showed that: producing the crop during the minor season with rainfall was not profitable; producing the crop during the major season was profitable when the half rate of fertilizer, mulched (F1M1 ); full rate fertilizer, mulched (F2 M1 ) and full rate fertilizer no mulch (F2 M0 ) treatments were applied, with the F1M1 ranking first as the most profitable option. This was shown by the comparative net income per hectare of: ¢1,215,000, ¢1,201,020 and ¢819,020 for the (F1M1 ), (F2M1 ) and (F2M0 ) respectively. Producing garden eggs with Leucaena mulch in hedgerow intercropping could reduce fertilizer requirement, at least by half. Hedgerow intercropping with garden eggs is therefore profitable and may become an attractive alternative to small-scale farmers as prices of inorganic fertilizer continue to increase over the years.Journal of Science and Technology (Ghana) Vol. 27 (2) 2007: pp. 62-7

Joint evolution of multiple social traits: a kin selection analysis

General models of the evolution of cooperation, altruism and other social behaviours have focused almost entirely on single traits, whereas it is clear that social traits commonly interact. We develop a general kin-selection framework for the evolution of social behaviours in multiple dimensions. We show that whenever there are interactions among social traits new behaviours can emerge that are not predicted by one-dimensional analyses. For example, a prohibitively costly cooperative trait can ultimately be favoured owing to initial evolution in other (cheaper) social traits that in turn change the cost-benefit ratio of the original trait. To understand these behaviours, we use a two-dimensional stability criterion that can be viewed as an extension of Hamilton's rule. Our principal example is the social dilemma posed by, first, the construction and, second, the exploitation of a shared public good. We find that, contrary to the separate one-dimensional analyses, evolutionary feedback between the two traits can cause an increase in the equilibrium level of selfish exploitation with increasing relatedness, while both social (production plus exploitation) and asocial (neither) strategies can be locally stable. Our results demonstrate the importance of emergent stability properties of multidimensional social dilemmas, as one-dimensional stability in all component dimensions can conceal multidimensional instability

Tagged tiger shark (Galeocerda cuvieri) landed atTuticorin

The shark was caught by a mechanised Tuticorin type boat using hooks and line . The fish was caught at a distance of 40 km from shore southeast of Tuticorin in the 26 fathom depth area The fish weighed 130 kg and was sold by auction for Rupees 916. Morphometric measurements (in mm) of tagged tiger shark Galeocerda cuvieri caught off Tuticorin are Total length 2,050, Fork length 1,680, and detailed morphometry were recorded

Signatures of non-gaussianity in the isocurvature modes of primordial black hole dark matter

Primordial black holes (PBHs) are black holes which may have formed very early on during the radiation dominated era in the early universe. We present here a method by which the large scale perturbations in the density of primordial black holes may be used to place tight constraints on non-gaussianity if PBHs account for dark matter (DM). The presence of local-type non-gaussianity is known to have a significant effect on the abundance of primordial black holes, and modal coupling from the observed CMB scale modes can significantly alter the number density of PBHs that form within different regions of the universe, which appear as DM isocurvature modes. Using the recent \emph{Planck} constraints on isocurvature perturbations, we show that PBHs are excluded as DM candidates for even very small local-type non-gaussianity, $|f_{NL}|\approx0.001$ and remarkably the constraint on $g_{NL}$ is almost as strong. Even small non-gaussianity is excluded if DM is composed of PBHs. If local non-Gaussianity is ever detected on CMB scales, the constraints on the fraction of the universe collapsing into PBHs (which are massive enough to have not yet evaporated) will become much tighter.Comment: 23 pages, 11 figures. V2: minor corrections and changes, matches published versio

Testing Behavioral Hypotheses Using an Integrated Model of Grocery Store Shopping Path and Purchase Behavior

We examine three sets of established behavioral hypotheses about consumers\u27 in-store behavior using field data on grocery store shopping paths and purchases. Our results provide field evidence for the following empirical regularities. First, as consumers spend more time in the store, they become more purposeful—they are less likely to spend time on exploration and more likely to shop/buy. Second, consistent with “licensing” behavior, after purchasing virtue categories, consumers are more likely to shop at locations that carry vice categories. Third, the presence of other shoppers attracts consumers toward a store zone but reduces consumers\u27 tendency to shop there

The Traveling Salesman Goes Shopping: The Systematic Deviations of Grocery Paths from TSP-Optimality

We examine grocery shopping paths using the “Traveling Salesman Problem” (TSP) as a normative frame of reference. We define the “TSP-path” for each shopper as the shortest path that connects all of his purchases. We then decompose the length of each observed path into three components: the length of the TSP-path, the additional distance due to order deviation (i.e., not following the TSP-order of category purchases), and the additional distance due to travel deviation (i.e., not following the shortest point-to-point route). We explore the relationship between these deviations and different aspects of in-store shopping/purchase behavior. Among other things, our results suggest that (1) a large proportion of trip length is due to travel deviation; (2) paths that deviate substantially from the TSP solution are associated with larger shopping baskets; (3) order deviation is strongly associated with purchase behavior, while travel deviation is not; and (4) shoppers with paths closer to the TSP solution tend to buy more from frequently purchased product categories

Path Data in Marketing: An Integrative Framework and Prospectus for Model Building

Many data sets, from different and seemingly unrelated marketing domains, all involve paths—records of consumers\u27 movements in a spatial configuration. Path data contain valuable information for marketing researchers because they describe how consumers interact with their environment and make dynamic choices. As data collection technologies improve and researchers continue to ask deeper questions about consumers\u27 motivations and behaviors, path data sets will become more common and will play a more central role in marketing research. To guide future research in this area, we review the previous literature, propose a formal definition of a path (in a marketing context), and derive a unifying framework that allows us to classify different kinds of paths. We identify and discuss two primary dimensions (characteristics of the spatial configuration and the agent) as well as six underlying subdimensions. Based on this framework, we cover a range of important operational issues that should be taken into account as researchers begin to build formal models of path-related phenomena. We close with a brief look into the future of path-based models, and a call for researchers to address some of these emerging issues

Calculating the mass fraction of primordial black holes

We reinspect the calculation for the mass fraction of primordial black holes (PBHs) which are formed from primordial perturbations, finding that performing the calculation using the comoving curvature perturbation c in the standard way vastly overestimates the number of PBHs, by many orders of magnitude. This is because PBHs form shortly after horizon entry, meaning modes significantly larger than the PBH are unobservable and should not affect whether a PBH forms or not - this important effect is not taken into account by smoothing the distribution in the standard fashion. We discuss alternative methods and argue that the density contrast, Δ, should be used instead as super-horizon modes are damped by a factor k2. We make a comparison between using a Press-Schechter approach and peaks theory, finding that the two are in close agreement in the region of interest. We also investigate the effect of varying the spectral index, and the running of the spectral index, on the abundance of primordial black holes