Strategic patents and asymmetric litigation costs as entry deterrence instruments

To spur innovation, the patent protection system grants the patentee limited monopoly power to recoup his R&D investment, although, in general, allowing the use of the public good "innovation" is socially efficient. But patents and patent threats can also be used strategically, e.g. to deter entry from competitors. This note shows that, besides incumbency, the present patent protection system constitutes an additional strategic instrument that favors the incumbent, because asymmetric litigation costs may deter entry from potential rivals.Entry deterrence

Two-state system driven by imperfect pi pulses: an estimate of the error accumulation in bang-bang control methods

The evolution of a two-state system driven by a sequence of imperfect pi pulses (with random phase or amplitude errors) is calculated. The resulting decreased fidelity is used to derive a plausible limit on the performance of "bang-bang" control methods for the suppression of decoherence.Comment: 9 pages, 3 figures; submitted to Journal of Modern Optic

Dynamical compensation and structural identifiability: analysis, implications, and reconciliation

The concept of dynamical compensation has been recently introduced to describe the ability of a biological system to keep its output dynamics unchanged in the face of varying parameters. Here we show that, according to its original definition, dynamical compensation is equivalent to lack of structural identifiability. This is relevant if model parameters need to be estimated, which is often the case in biological modelling. This realization prompts us to warn that care should we taken when using an unidentifiable model to extract biological insight: the estimated values of structurally unidentifiable parameters are meaningless, and model predictions about unmeasured state variables can be wrong. Taking this into account, we explore alternative definitions of dynamical compensation that do not necessarily imply structural unidentifiability. Accordingly, we show different ways in which a model can be made identifiable while exhibiting dynamical compensation. Our analyses enable the use of the new concept of dynamical compensation in the context of parameter identification, and reconcile it with the desirable property of structural identifiability

Multicriteria global optimization for biocircuit design

One of the challenges in Synthetic Biology is to design circuits with increasing levels of complexity. While circuits in Biology are complex and subject to natural tradeoffs, most synthetic circuits are simple in terms of the number of regulatory regions, and have been designed to meet a single design criterion. In this contribution we introduce a multiobjective formulation for the design of biocircuits. We set up the basis for an advanced optimization tool for the modular and systematic design of biocircuits capable of handling high levels of complexity and multiple design criteria. Our methodology combines the efficiency of global Mixed Integer Nonlinear Programming solvers with multiobjective optimization techniques. Through a number of examples we show the capability of the method to generate non intuitive designs with a desired functionality setting up a priori the desired level of complexity. The presence of more than one competing objective provides a realistic design setting where every design solution represents a trade-off between different criteria. The tool can be useful to explore and identify different design principles for synthetic gene circuits

Seeds banks of desert annuals in an aridity gradient in the southern Atacama Desert

*Background/Question/Methods*
Annual plant communities are important components of the biodiversity found in the coastal southern Atacama Desert in Chile. Moreover, they are an important economic resource for the human communities living in that area. These plant communities develop, after heavy rainfall episodes, a phenomenon locally known as the “blooming of the desert”. Although the minimum rainfall thresholds for these plants to emerge are relatively well known, little is known about their seed banks, its composition, dynamics and variation across the latitudinal aridity gradient from south to north. This system is interesting to study species coexistence, as well as, to look for exotic plants invasion, since previous studies have shown that exotic annual plants decreases in importance northwards. We hypothesize that, as a result of the gradient, we should find more seeds of annuals in the southern part because of the increase of exotic species. The lowest diversity will be found in the northern limit, while the highest in the middle part of the gradient, coincident with a natural protected area, and less influence of exotics. In terms of seed size and viability, we should find larger and more viable seeds in the southern limit of the gradient, probably contrasting with smaller and more dormant seeds to the north. To test these hypotheses we selected 8 sites along the gradient and collected soil samples after seed set in December 2008 for seed bank determination. 

*Results/Conclusions*
According to our hypothesis we found more seeds in the southern part of the gradient. The northern seed banks (Rodillo and Cisne) are characterized by their low number of seeds and low species richness, according with their more extreme aridity. The central and southern seed banks have more than two times higher number and species richness than the northern ones. Southern seed banks (Lagunillas, Romeral and Punta Choros) contain more exotics’ seeds; meanwhile central seed banks (Pajonales, Carrizal Bajo and Los Bronces) have less seeds, and less exotics’ seeds. These results suggest that the increased seed number in the southern portion of the gradient could be due to an increased number of exotic species, rather than an increased diversity of native annuals. More viable and larger seeds were found in the southern sites, meanwhile, smaller seeds were found to the north indicating the use of a cautious opportunism strategy by these species. This is the first report on seed banks composition of this Atacama Desert area

Specialization in the bargaining family

We develop a two period family decision making model in which spouses bargain over their contributions to a family public good and the distribution of private consumption. In contrast to most models in the literature, specialization within the couple emerges endogenously from the production of the public good, and is not caused by exogenous differences between the spouses. Increasing marginal benefits of labour market experience make specialization efficient, even if both spouses have equal market and household productivities on the outset. If spouses are not able to enter into a binding contract governing the distribution of private consumption in the second period, the spouse specialized in market labour cannot commit to compensate the other spouse for foregone investments in earnings power. As a consequence, this spouse may withdraw part of his/her contribution and the provision level of the household good is likely to be inefficiently low.Family bargaining, specialization, private provision of public goods

The wage gap and the leisure gap for double earner couples

Empirical research has consistently shown that, on average, men are paid higher wages than women. At the same time, men enjoy more leisure time than women. We develop a model of private provision of family public goods to analyze whether the wage gap and the leisure gap are related. Within a nonco- operative framework, different bargaining power situations within a couple are considered which lead to different empirical hypotheses. With data from the German Socio-Economic Panel we focus on the leisure gap and the wage gap within double earner couples and in this way are able to discriminate among the theoretical models. Our random effects estimates show that husbands have a stronger bargaining position and this advantage results in them enjoying, other things equal, more leisure time that their wives.