Fynbos connectivity as a function of dispersal distance and the implications for bird conservation in the greater Cape Town area

Connectivity is defined as the degree to which a landscape facilitates an organisms' movement. It is considered a vital element of landscape structure with key implications for metapopulation survival and ecological processes such as pollination. The connectivity of a landscape changes depending on an organisms' ability to move between patches of favourable habitat and this in turn is related to the dispersal ability of the organism. Connectivity thus changes with the scale at which the landscape is viewed; however the relationship between connectivity and dispersal ability is overlooked in many studies. This study looks at the connectivity of two types of fynbos: Highland fynbos (Thicket, Bushland, Bushclumps and High fynbos) which makes up 22.7%, and Lowland fynbos (Shrubland and Low Fynbos) which makes up 28% of the studied extent. These vegetation types are outlined by the National Land Cover Database (NLCD 2000) and analysed as a function of organism dispersal ability in the greater Cape Town area. It is shown that a relationship between dispersal ability and connectivity exists; however the relationship is not linear but sigmoidal with inflection points at 45% connectivity. This raises the question of a connectivity threshold in the Fynbos Biome. Characteristics of the landscape are assessed and it is shown that Fynbos vegetation in the greater Cape Town area is highly fragmented. Fragmentation and habitat loss decrease connectivity and are thus important factors in conservation. In order to simulate the effect of further fragmentation through habitat loss, patches of increasing size were removed and the results put into context for conservation of both the vegetation types and the dispersing organisms dependent on them. The importance of conserving patches of remnant vegetation in order to facilitate organism dispersal is highlighted by this study

A turbulent diatom vs dinoflagellate phytoplankton biomass model

Phytoplankton blooms play an important role in global primary productivity and the dynamics of blooms are of interest to modellers. Diatom dominated phytoplankton blooms followed by dinoflagellate blooms are common in the Southern Benguela, and are often associated with Harmful Algal Blooms. A well-known ecological explanation for the succession of diatoms to dinoflagellates is given by Margalef’s Mandala which attributes the successional change to the interaction between turbulence and available nutrient concentration. This study introduced a simple variable accounting for the effects of turbulence to a numerical model describing diatom and dinoflagellate growth in order to emulate the common successional pattern. Succession was successfully modelled by reducing the maximum growth rate of diatoms in stratified conditions. The model was then used to investigate the predictions of Margalef’s Mandala. This study unpicks the relationship between nutrients, turbulence, diatoms and dinoflagellates through a simple 0D phytoplankton model with interesting insight into the role of turbulence in phytoplankton dynamics

Copyright Infringement in Sound Recording: How Courts and Legislatures Can Get in Vogue in a Post-Ciccone World

Music sampling is a legally complex and ambiguous area, with staggeringly high costs attached for copyright infringers. The legality of sampling frequently depends upon what jurisdiction the inquiry into the sampling takes place in, and has been guided by inconsistently applied doctrines of fair use, de minimis, and copyright infringement. The Ninth Circuit’s decision in VMG Salsoul v. Ciccone has dramatically highlighted these inconsistencies. This note suggests a four-part solution to resolve the tensions in copyrightable sound recordings magnified by the recent circuit split created by VMG Salsoul v. Ciccone. It incorporates elements of de minimis and fair use, a robust licensing scheme, and administrative oversight. While Ciccone fails to resolve the complex issues inherent to musical sampling and copyright infringement, it does create an opportunity for a joint legislative-judicial solution

Visualization of the distribution of autophosphorylated calcium/calmodulin-dependent protein kinase II after tetanic stimulation in the CA1 area of the hippocampus

Autophosphorylation of calcium/calmodulin-dependent protein kinase II (CaMKII) at threonine-286 produces Ca2+-independent kinase activity and has been proposed to be involved in induction of long-term potentiation by tetanic stimulation in the hippocampus. We have used an immunocytochemical method to visualize and quantify the pattern of autophosphorylation of CaMKII in hippocampal slices after tetanization of the Schaffer collateral pathway. Thirty minutes after tetanic stimulation, autophosphorylated CaM kinase II (P-CaMKII) is significantly increased in area CA1 both in apical dendrites and in pyramidal cell somas. In apical dendrites, this increase is accompanied by an equally significant increase in staining for nonphosphorylated CaM kinase II. Thus, the increase in P-CaMKII appears to be secondary to an increase in the total amount of CaMKII. In neuronal somas, however, the increase in P-CaMKII is not accompanied by an increase in the total amount of CaMKII. We suggest that tetanic stimulation of the Schaffer collateral pathway may induce new synthesis of CaMKII molecules in the apical dendrites, which contain mRNA encoding its alpha-subunit. In neuronal somas, however, tetanic stimulation appears to result in long-lasting increases in P-CaMKII independent of an increase in the total amount of CaMKII. Our findings are consistent with a role for autophosphorylation of CaMKII in the induction and/or maintenance of long-term potentiation, but they indicate that the effects of tetanus on the kinase and its activity are not confined to synapses and may involve induction of new synthesis of kinase in dendrites as well as increases in the level of autophosphorylated kinase

A socio-ecological systems approach to understanding development in a dynamic world : a case study of traditional agriculture in Pondoland, South Africa

Arguably one of the greatest challenges currently facing humankind is the linking of environmental sustainability with poverty reduction and social justice. These issues all come to a head in the rural smallholder agricultural regions of "underdeveloped" Africa .In these settings climate change and food security are but two of the many challenges faced on a daily basis, compounded by the need for "development". Through a case study of smallholder farmers facing multiple contested development trajectories, this research takes a social-ecological systems approach in order to: 1. investigate the past, present and future dynamics of smallholder agriculture and food practices in mPondo communities of the Wild Coast 2. locate the role of agriculture and agri-food systems in the local development discourses 3. describe the perceived opportunities and challenges which face the local agri-food system Through semi-structured interviews, informal discussions, workshops and participant observation in three regions of the Wild Coast of the Eastern Cape a trend of rapid cultural erosion was observed. Many traditional crops are no longer cultivated as farmers turn to commercial seeds and modern cooking methods. Three dominant development trajectories are explored for one region, focusing on the AmaDiba community whose history of resisting imposed development is again being tested by contentious titanium mining proposed in nearby Xolobeni. A central finding is that while resisting imposed development in order to achieve a self-defined development which values mPondo traditions and subsistence off the land, these communities - described as possessing strong community agency - are losing the very culture they are fighting to defend. This is made clear through the social-ecological systems approach of resilience theory. In building resilience to imposed development the community has become vulnerable to other disturbances. As this traditional agri-food system continues to face the enduring shocks of global environmental and social change, the communities must recognise their fragilities as well as the threats which have been overlooked in the past. This study therefore suggests that the community exploit this stage of readjustment so as to reorganise, building on local culture and tradition, through an integrated approach to development which combines agriculture, traditional food and tourism

BDNF Val66Met Polymorphism Influences Age Differences in Microstructure of the Corpus Callosum

Brain-derived neurotrophic factor (BDNF) plays an important role in neuroplasticity and promotes axonal growth, but its secretion, regulated by a BDNF gene, declines with age. The low-activity (met) allele of common polymorphism BDNF val66met is associated with reduced production of BDNF. We examined whether age-related reduction in the integrity of cerebral white matter (WM) depends on the BDNF val66met genotype. Forty-one middle-aged and older adults participated in the study. Regional WM integrity was assessed by fractional anisotropy (FA) computed from manually drawn regions of interest in the genu and splenium of the corpus callosum on diffusion tensor imaging scans. After controlling for effects of sex and hypertension, we found that only the BDNF 66met carriers displayed age-related declines in the splenium FA, whereas no age-related declines were shown by BDNF val homozygotes. No genotype-related differences were observed in the genu of the corpus callosum. This finding is consistent with a view that genetic risk for reduced BDNF affects posterior regions that otherwise are considered relatively insensitive to normal aging. Those individuals with a genetic predisposition for decreased BDNF expression may not be able to fully benefit from BDNF-based plasticity and repair mechanisms

Adult Age Differences and the Role of Cognitive Resources in Perceptual-Motor Skill Acquisition: Application of a Multilevel Negative Exponential Model

The effects of advanced age and cognitive resources on the course of skill acquisition are unclear, and discrepancies among studies may reflect limitations of data analytic approaches. We applied a multilevel negative exponential model to skill acquisition data from 80 trials (four 20-trial blocks) of a pursuit rotor task administered to healthy adults (19-80 years old). The analyses conducted at the single-trial level indicated that the negative exponential function described performance well. Learning parameters correlated with measures of task-relevant cognitive resources on all blocks except the last and with age on all blocks after the second. Thus, age differences in motor skill acquisition may evolve in 2 phases: In the first, age differences are collinear with individual differences in task-relevant cognitive resources; in the second, age differences orthogonal to these resources emerg

Modeling the emergence of a typological anomaly: Vowel nasalization in French

Proceedings of the 37th Annual Meeting of the Berkeley Linguistics Society (2013), pp. 155-16

Neuroanatomical Correlates of Fluid Intelligence in Healthy Adults and Persons with Vascular Risk Factors

The main objective of this study was to examine the effects of regional brain changes on cognitive decline and the modifying influence of vascular risk (VR) factors. We present latent difference score analyses of associations among 5-year changes in 12 regional brain volumes and age-sensitive cognitive functions in 87 adults (32 with identifiable VR factors). We found reliable individual differences in volume change for 11 of the 12 brain regions but not in the cognitive measures that showed average longitudinal decline. Thus, associations between rates of change in fluid intelligence and brain volumes could not be assessed. We observed, however, that lower levels of fluid intelligence were associated with smaller prefrontal and hippocampal volumes. Lower fluid intelligence scores were also linked to greater longitudinal shrinkage of the entorhinal cortex (EC). After accounting for the effects of age, sex, and VR factors, the orbitofrontal cortex and the prefrontal white matter (PFw) volumes as well as the 5-year change in the EC volume predicted fluid intelligence level. VR was independently associated with smaller prefrontal volumes and lower fluid intelligence. Thus, prefrontal and medial-temporal systems may play different roles in age-related differences and changes in cognitive performanc

Epidermal Threads Reveal the Origin of Hagfish Slime

When attacked, hagfishes produce a soft, fibrous defensive slime within a fraction of a second by ejecting mucus and threads into seawater. The rapid setup and remarkable expansion of the slime make it a highly effective and unique form of defense. How this biomaterial evolved is unknown, although circumstantial evidence points to the epidermis as the origin of the thread- and mucus-producing cells in the slime glands. Here, we describe large intracellular threads within a putatively homologous cell type from hagfish epidermis. These epidermal threads averaged ~2 mm in length and ~0.5 μm in diameter. The entire hagfish body is covered by a dense layer of epidermal thread cells, with each square millimeter of skin storing a total of ~96 cm threads. Experimentally induced damage to a hagfish’s skin caused the release of threads, which together with mucus, formed an adhesive epidermal slime that is more fibrous and less dilute than the defensive slime. Transcriptome analysis further suggests that epidermal threads are ancestral to the slime threads, with duplication and diversification of thread genes occurring in parallel with the evolution of slime glands. Our results support an epidermal origin of hagfish slime, which may have been driven by selection for stronger and more voluminous slime