Endogenous R&D Investment and Market Structure: A Case Study of the Agricultural Biotechnology Industry

Over the past three decades, the agricultural biotechnology sector has been characterized by rapid innovation, market consolidation, and a more exhaustive definition of property rights. The industry attributes consistently identified by the literature and important to this analysis include: (i) endogenous sunk costs in the form of expenditures on R&D; (ii) seed and agricultural chemical technologies that potentially act as complements within firms and substitutes across firms; and (iii) property rights governing plant and seed varieties that have become more clearly defined since the 1970s. This paper adds to the stylized facts of the agricultural biotechnology industry to include the ability of firms to license technology, a phenomenon observed only recently in the market as licensing was previously precluded by high transactions costs and “anti-stacking” provisions. We extend Sutton's theoretical framework of endogenous sunk costs and market structure to incorporate the ability of firms to license technology under well-defined property rights, an observed characteristic not captured in previous analyses of the sector. Our model implies that technology licensing leads to lower levels of industry concentration then what would be found under Sutton's model, but that industry concentration remains bounded away from perfect competition as market size becomes large.licensing, market structure, R&D, agricultural biotechnology, Research and Development/Tech Change/Emerging Technologies, L22, L24, Q16,

Variation in local population size predicts social network structure in wild songbirds

1. The structure of animal societies is a key determinant of many ecological and evolutionary processes. Yet, we know relatively little about the factors and mechanisms that underpin detailed social structure. 2. Among other factors, social structure can be influenced by habitat configuration. By shaping animal movement decisions, heterogeneity in habitat features, such as vegetation and the availability of resources, can influence the spatiotemporal distribution of individuals and subsequently key socioecological properties such as the local population size and density. Differences in local population size and density can impact opportunities for social associations and may thus drive substantial variation in local social structure. 3. Here, we investigated spatiotemporal variation in population size at 65 distinct locations in a small songbird, the great tit (Parus major), and its effect on social network structure. We first explored the within-location consistency of population size from weekly samples and whether the observed variation in local population size was predicted by the underlying habitat configuration. Next, we created social networks from the birds’ foraging associations at each location for each week and examined if local population size affected social structure. 4. We show that population size is highly repeatable within locations across weeks and years and that some of the observed variation in local population size was predicted by the underlying habitat, with locations closer to the forest edge having on average larger population sizes. Further, we show that local population size affected social structure inferred by four global network metrics. Using simple simulations, we then reveal that much of the observed social structure is shaped by social processes. Across different population sizes, the birds’ social structure was largely explained by their preference to forage in flocks. In addition, over and above effects of social foraging, social preferences between birds (i.e. social relationships) shaped certain network features such as the extent of realized social connections. 5. Our findings thus suggest that individual social decisions substantially contribute to shaping certain social network features over-and-above effects of population size alone

CADASIL with Cysteine-Sparing Notch-3 Mutation

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an inherited vascular dementia1,2. The mutations implicated in CADASIL are located on Chromosome 19 within the NOTCH3 gene, which encodes a transmembrane receptor that is primarily expressed in vascular smooth muscle cells. Over one hundred distinct mutations have been described which alter the number of cysteine residues in the extracellular region and result in a CADASIL phenotype. Cysteine-sparing mutations with CADASIL phenotype have been reported four times. Two German kindreds were recently described with a CADASIL-like phenotype associated with a cysteine-sparing NOTCH3 mutation. We present another such case in a third family, with the same point mutation described in the German families. The patient is a 55-year-old Caucasian woman with five years of progressive cognitive impairment, chronic headaches, and gait instability. Prior to presenting at our clinic, she had been diagnosed with Alzheimer disease. Her neuropsychological testing (Table One) and MRI studies (Figure One), however, were more consistent with a subcortical vascular dementia. Her genetic CADASIL screen was “negative” although a missense mutation in NOTCH3 was identified. At the time of that test, no cysteine-sparing mutations causing CADASIL had been reported. Workup of other family members is ongoing. Elucidation of this case will provide corroboration of a cysteine-sparing CADASIL mutation, and will inform the discussion of whether this represents a distinct entity or a CADASIL subtype. With the field of neurogenetics rapidly evolving, interpretation of standard genetic tests may need to include literature review to ascertain the correct diagnosis

Neurologic and Psychiatric Co-morbidity in Neuropsychiatry Training

Summary: Discusses a study on combined neuropsychiatry training for establishing competency in neuropsychiatry

First measurement of gravitational lensing by cosmic voids in SDSS

We report the first measurement of the diminutive lensing signal arising from matter underdensities associated with cosmic voids. While undetectable individually, by stacking the weak gravitational shear estimates around 901 voids detected in SDSS DR7 by Sutter et al. (2012a), we find substantial evidence for a depression of the lensing signal compared to the cosmic mean. This depression is most pronounced at the void radius, in agreement with analytical models of void matter profiles. Even with the largest void sample and imaging survey available today, we cannot put useful constraints on the radial dark-matter void profile. We invite independent investigations of our findings by releasing data and analysis code to the public at https://github.com/pmelchior/void-lensingComment: 6 pages, 5 figures, as accepted by MNRA

The Differential Diagnosis of Congenital Disorders that Include Psychosis

Summary: Neuropsychiatrists should be aware of congenital disorders that can present with psychosis, however rarely. Recommends a differential diagnosticapproach based on estimated prevalence of the disorders and their most prominent associated neuropsychiatric features

The Role of Neuropsychiatrists in Medical Science

The re-emergence of neuropsychiatry in the twentieth century occurred in the context of a history of neuropsychiatric contributions to medical science. In parallel to the growth of neuropsychiatry as a medical specialty, psychiatry has benefitted from developments in neuroscience, many of these built upon foundations established by neuropsychiatrists. We sought to enumerate the contributions by psychiatrists with neurological training to advances in medical science

Divergence in evolutionary potential of life-history traits among wild populations is predicted by differences in climatic conditions

Short-term adaptive evolution represents one of the primary mechanisms allowing species to persist in the face of global change. Predicting the adaptive response at the species level requires reliable estimates of the evolutionary potential of traits involved in adaptive responses, as well as understanding how evolutionary potential varies across a species’ range. Theory suggests that spatial variation in the fitness landscape due to environmental variation will directly impact the evolutionary potential of traits. However, empirical evidence on the link between environmental variation and evolutionary potential across a species range in the wild is lacking. In this study, we estimate multivariate evolutionary potential (via the genetic variance–covariance matrix, or G-matrix) for six morphological and life history traits in 10 wild populations of great tits (Parus major) distributed across Europe. The G-matrix significantly varies in size, shape, and orientation across populations for both types of traits. For life history traits, the differences in G-matrix are larger when populations are more distant in their climatic niche. This suggests that local climates contribute to shaping the evolutionary potential of phenotypic traits that are strongly related to fitness. However, we found no difference in the overall evolutionary potential (i.e., G-matrix size) between populations closer to the core or the edge of the distribution area. This large-scale comparison of G-matrices across wild populations emphasizes that integrating variation in multivariate evolutionary potential is important to understand and predict species’ adaptive responses to new selective pressures

Negative frequency dependent prey selection by two canid predators and its implications for the conservation of a threatened rodent in arid Australia

Unprecedented anthropogenic changes to biodiversity and biogeography demand a greater understanding of the consequences of altered faunal composition for ecosystem functioning. Selective predation has important, yet poorly understood effects on ecosystem stability, and can be strongly influenced by the relative frequencies of different prey types in the environment. Yet, how predators adjust their selection for prey according to their environmental frequency is often overlooked. Here, we assessed frequency dependent selection of prey by dingoes and foxes in the Australian desert, biannually, across a nine-year period (2007-2016). Both predators exhibited potentially destabilizing, negative frequency dependent selection for prey. Foxes persisted to preferentially consume a threatened, native rodent (Notomys fuscus) when it was environmentally scarce. Bolstered by the observation that N.fuscus occurs at low densities in areas where foxes are common, our results suggest that N.fuscus is particularly vulnerable to predation by this predator; possibly because it is naive and/or lacks adaptations to avoid or escape predation by the relatively recently introduced fox. Dingoes tended to consume reptiles when they were scarce; potentially constituting a conservation concern if selected reptilian taxa are threatened. Foxes avoided, thus were unlikely to control populations of overabundant kangaroos, while both foxes and dingoes showed a preference for, and may therefore control populations of invasive rabbits. The integration of our results into the relative suites of (de)stabilizing influences exerted by dingoes and foxes is important to provide a more dynamic insight into how each predator impacts their naturally fluctuating ecosystems

Social learning mechanisms shape transmission pathways through replicate local social networks of wild birds

The emergence and spread of novel behaviours via social learning can lead to rapid population-level changes whereby the social connections between individuals shape information flow. However, behaviours can spread via different mechanisms and little is known about how information flow depends on the underlying learning rule individuals employ. Here, comparing four different learning mechanisms, we simulated behavioural spread on replicate empirical social networks of wild great tits and explored the relationship between individual sociality and the order of behavioural acquisition. Our results reveal that, for learning rules dependent on the sum and strength of social connections to informed individuals, social connectivity was related to the order of acquisition, with individuals with increased social connectivity and reduced social clustering adopting new behaviours faster. However, when behavioural adoption depends on the ratio of an individuals’ social connections to informed versus uninformed individuals, social connectivity was not related to the order of acquisition. Finally, we show how specific learning mechanisms may limit behavioural spread within networks. These findings have important implications for understanding whether and how behaviours are likely to spread across social systems, the relationship between individuals’ sociality and behavioural acquisition, and therefore for the costs and benefits of sociality