THE INSTITUTIONAL ORIGINS OF DEFORESTATION IN LATIN AMERICA

Land Economics/Use,

"Free-Process" and "Only-way" Arguments

This is the author accepted manuscript. The final version is available from Baker Publishing Group via the link in this recor

Do 18-month-olds really attribute mental states to others? A critical test

In the research reported here, we investigated whether 18-month-olds would use their own past experience of visual access to attribute perception and consequent beliefs to other people. Infants in this study wore either opaque blindfolds (opaque condition) or trick blindfolds that looked opaque but were actually transparent (trick condition). Then both groups of infants observed an actor wearing one of the same blindfolds that they themselves had experienced, while a puppet removed an object from its location. Anticipatory eye movements revealed that infants who had experienced opaque blindfolds expected the actor to behave in accordance with a false belief about the object's location, but that infants who had experienced trick blindfolds did not exhibit that expectation. Our results suggest that 18-month-olds used self-experience with the blindfolds to assess the actor's visual access and to update her belief state accordingly. These data constitute compelling evidence that 18-month-olds infer perceptual access and appreciate its causal role in altering the epistemic states of other people

Baby steps: investigating the development of perceptual-motor couplings in infancy

There are cells in our motor cortex that fire both when we perform and when we observe similar actions. It has been suggested that these perceptual-motor couplings in the brain develop through associative learning during correlated sensorimotor experience. Although studies with adult participants have provided support for this hypothesis, there is no direct evidence that associative learning also underlies the initial formation of perceptual–motor couplings in the developing brain. With the present study we addressed this question by manipulating infants’ opportunities to associate the visual and motor representation of a novel action, and by investigating how this influenced their sensorimotor cortex activation when they observed this action performed by others. Pre-walking 7–9-month-old infants performed stepping movements on an infant treadmill while they either observed their own real-time leg movements (Contingent group) or the previously recorded leg movements of another infant (Non-contingent control group). Infants in a second control group did not perform any steps and only received visual experience with the stepping actions. Before and after the training period we measured infants’ sensorimotor alpha suppression, as an index of sensorimotor cortex activation, while they watched videos of other infants’ stepping actions. While we did not find greater sensorimotor alpha suppression following training in the Contingent group as a whole, we nevertheless found that the strength of the visuomotor contingency experienced during training predicted the amount of sensorimotor alpha suppression at post-test in this group. We did not find any effects of motor experience alone. These results suggest that the development of perceptual–motor couplings in the infant brain is likely to be supported by associative learning during correlated visuomotor experience

The effects of stocking density and ration on survival and growth of winged pearl oyster (Pteria penguin) larvae fed commercially available micro-algae concentrates

AbstractCommercially available micro-algae concentrates have been successfully used as an alternative to live micro-algae as a food source during routine larval culture of the winged pearl oyster, Pteria penguin. This supports the development of simplified hatchery facilities and larval rearing protocols that are more appropriate to Pacific island nations. An optimal feeding regime based on these products that also accounts for larval stocking density is yet to be developed. Two experiments were conducted at a commercial pearl oyster hatchery facility in the Kingdom of Tonga to examine the combined effects of stocking density and ration on survival and growth of both D-stage (from 1 to 8 days post-fertilsation) and umbo-stage (from 8 to 17 days) P. penguin larvae. Both experiments used a factorial design combining three larval stocking densities (D-stage: 2, 6 & 10 larvaemL−1; umbo-stage: 1, 3 & 5 larvaemL−1) and three rations (D-stage: 5, 10 & 15 cellsmL−1; umbo-stage: 10, 15 & 20 cellsmL−1). Survival during D-stage was significantly improved in aquaria stocked below 10 larvaemL−1, whereby a density of 6mL−1 maximised larval production. An intermediate ration of 10×103 cellsmL−1 maximised both survival and growth during D-stage. Increasing the initial stocking density of umbo-stage larvae from 1 to 3mL−1 resulted in significant reductions in both survival and growth. Growth of umbo-stage larvae stocked at a density of 1mL−1 increased significantly when ration remained below 20×103 cellsmL−1. The results of this study provide a basis for optimised hatchery culture protocols for P. penguin that are more appropriate to Pacific island nations

Differential Regulation of Growth-Promoting Signalling Pathways by E-Cadherin

Background: Despite the well-documented association between loss of E-cadherin and carcinogenesis, as well as the link between restoration of its expression and suppression of proliferation in carcinoma cells, the ability of E-cadherin to modulate growth-promoting cell signalling in normal epithelial cells is less well understood and frequently contradictory. The potential for E-cadherin to co-ordinate different proliferation-associated signalling pathways has yet to be fully explored. Methodology/Principal Findings: Using a normal human urothelial (NHU) cell culture system and following a calcium-switch approach, we demonstrate that the stability of NHU cell-cell contacts differentially regulates the Epidermal Growth Factor Receptor (EGFR)/Extracellular Signal-Regulated Kinase (ERK) and Phosphatidylinositol 3-Kinase (PI3-K)/AKT pathways. We show that stable cell contacts down-modulate the EGFR/ERK pathway, whilst inducing PI3-K/AKT activity, which transiently enhances cell growth at low density. Functional inactivation of E-cadherin interferes with the capacity of NHU cells to form stable calcium-mediated contacts, attenuates E-cadherin-mediated PI3-K/AKT induction and enhances NHU cell proliferation by allowing de-repression of the EGFR/ERK pathway and constitutive activation of beta-catenin-TCF signalling. Conclusions/Significance: Our findings provide evidence that E-cadherin can differentially and concurrently regulate specific growth-related signalling pathways in a context-specific fashion, with direct, functional consequences for cell proliferation and population growth. Our observations not only reveal a novel, complex role for E-cadherin in normal epithelial cell homeostasis and tissue regeneration, but also provide the basis for a more complete understanding of the consequences of E-cadherin loss on malignant transformation

Experiences of service users involved in recruitment for nursing courses: a phenomenological research study

The aim of this study was to gain insight into service users’ experiences of participating in recruitment for Adult, Mental Health and Child nursing studies at the authors’ university; to establish potential motivations behind such participation; and to make suggestions for improved future practice. The involvement of service users in nurse education and recruitment has for some years been required by the Nursing and Midwifery Council, but there is a dearth of publications on the meaning of that involvement to participating service users. It is hoped that this study will contribute to this body of knowledge. A phenomenological approach was selected, field-specific focus groups of service users being facilitated using a semi-structured interview format; these were audio recorded and transcribed. The data was analysed using thematic analysis. Participation was subject to the service users having been involved in recruitment to nursing studies at the authors’ university and the focus groups took place either at the university or at the child participants’ school. Themes identified demonstrated largely positive experiences and a sense of meaningful involvement for all concerned. Findings indicated a close link between the values of the participants and those of the wider NHS, benefits to a sense of wellbeing and achievement, as well as the need for greater ownership of the recruitment process by service users. Potential lessons for academics wishing to promote greater service user involvement in student recruitment are articulated

Thickness Design Curves for Portland Cement Concrete Pavements

Past experience indicates that thickness designs using portland cement concrete best agree with criterion used in the Portland Cement Association\u27s design method for 18-kip EAL of 2 to 3 million or less. For EALs greater than 2 to 3 million, past experience best agrees with criterion developed from the AASHO Road Test. Research herein indicates the two criterion become asymptotic to each other at approximately 2.5 million EAL. For a variation in thickness and elastic moduli in portland cement concrete, dense-graded aggregate, and sub grade elastic modulus, research indicates that a general conic equation (included herein) very closely duplicates the work at the bottom of the portland cement concrete caused by an 18-kip single axle load. The transition from a tensile strain to a work criterion is presented. Decreasing the thickness of dense-graded aggregate base caused a maximum increase of 0.15 inches in the thickness of portland cement concrete. Thus, the thicknesses of the portland cement concrete were averaged. The resulting thickness design curves are presented for a concrete elastic modulus of 4.2 million psi (Kentucky concrete strength)

Suggested Changes to Kentucky Statutes (Vehicle Weights and Dimensions)

The purposes of this report are: 1. To clearly define the terms \u27\u27tandem, tridem, and “triaxle. 2. To clearly define the term 600 pounds per inch width of tire as the width of the tread in contact with the pavement. 3. To make the axle load limits the same throughout the statutes. 4. To suggest elimination of indentified discriminatory legislation. 5. To recommend additional legislation: a. to clearly define the purpose and use of air-bag suspension systems -- those that can be raised or lowered by the driver, and b. to enable vehicle weight enforcement officers to use shipping documents as evidence to issue overweight citations without having to weigh the trucks. These documents may be in the possession of the driver, or in the files of the shipping and/ or receiving firms

Distributions of Strain Components and Work Within Flexible Pavement Structures

An investigation was made to determine the location along the centerline of the axle of the maximum strain energy density, or work, in the pavement as defined by classical physics. The location is under the inside edge of either dual tire. The most influential strain was the shear component. The distribution of shear strains and stresses with depth through the full-depth asphaltic concrete and into the subgrade was investigated. Using Simpson\u27s rule for an even number of increments, or using the trapezoidal rule, allows the summation of strain energy density calculated at various depths. This sum multiplied by a unit volume converts the strain energy density to work as defined by classical physics. The sum of work throughout the pavement structure provides a greater insight to the behavior of the pavement because all components of strain, or stress, are considered and the variation throughout the depth may be large according to the location within the tire print. The sum of strain energy density is much greater under the edge of the dual tire compared to that under the center of the dual tire, yet the magnitude of the strain energy density at the bottom of the asphaltic concrete may be nearly identical. For an 18-kip (80-kN) four-tired single axleload, the depth of maximum shear is approximately 35 to 40 percent of the thickness from the surface downward for a maximum pavement thickness of approximately 8 inches (203 mm); thereafter the depth of maximum shear moves toward the surface as the thickness increases. An investigation of shear stress indicated the maximum value was approximately 67 psi (0.46 GPa) due to an 18-kip (80-kN) single axleload and tire contact pressure of 80 psi (0.63 GPa). For an 80-kip (36-kN) tandem axleload and tire contact pressures of 100 psi (0.69 GPa), the shear stress increased o approximately 133 psi (0.92 GPa). As the tire contact pressures of 100 psi (o.69 GPa), the shear stress increased to approximately 133 psi (0.92 GPa). As the tire contact pressure increases, the shear stress may approach 200 psi (1.38 GPa). Recommendations include eliminating any construction plane between the 1- to 4-inch (25– to 102–mm) depth from the surface and determining the shear resistance of the asphaltic concrete mix to insure that the mix can withstand a higher shear stress that is currently being obtained. Target values of shear stress have not been recommended for adoption because a limiting value has not been found in the literature