Environmental Regulation and Technological Innovation with Spillovers

We present a two-period dynamic model of standard setting under asymmetric information to model the attempts by the Califormia Air Resources Board (CARB) in getting car manufacturers to comply with its phase-in of stringent emissions standards. After CARB chooses an initial emissions standard that ?rms are required to comply with, automakers respond by choosing R&D investment and production levels which provide CARB an imperfect signal whether they are more or less capable of complying with the standard. CARB resets the environmental standard and the ?rms once again choose research and production levels. Firms are Cournot duopolists in the product market and can choose to do research noncooperatively or cooperatively in the presence of spillovers. We show that ?rms will behave strategically and underinvest in research both under competitive and cooperative R&D, though the level of underinvestment — the ratchet effect — is greater under cooperative R&D when spillovers are large. We uncover a fundamental con?ict between the incentives of ?rms to do cooperative research and social welfare: that ?rms will want to engage in cooperative (resp. noncooperative) R&D only when spillovers are low (resp. high) while social welfare is greater under noncooperative (resp. cooperative) research.Car emissions; dynamic technology-forcing regulation; selfregulation; pre-commitment; cooperative R&D; ratchet effect.

No Till and Organic Farming Improve Soil Properties but Reduce Crop Yield Compared to Conventional Farming in a Swiss Farm Network

Soils are of vital importance for sustainable food production. In order to maintain or improve soil quality, it is necessary to develop strategies for a sustainable use of soil. Alternative cropping practices such as reduced tillage and improved crop rotation are more and more adopted with the aim of decreasing the impact of agriculture on the environment. However, their on-the-ground impact in Swiss farming systems still has to be assessed. In this study, we quantified the impact of three farming systems (conventional farming, no-till, and organic farming) on plant and soil chemical, biological and physical properties. Our study included 20 fields for each farming system. All selected fields were cultivated with winter wheat the year of sampling. Soil was sampled at four layers, 0-5 cm, 5-20 cm, 20-25 cm, 25-50 cm. The main variables analysed were grain yield, soil nutrient availability, organic carbon stocks, bulk density, aggregation, porosity and soil biology. This was complemented with a comprehensive survey to collect information about cropping practices at field and farm scale, including organic matter inputs, fertilisation, tillage, phytosanitary treatments, and crop rotation.Our results show a significant influence of cropping practices on plant and soil properties. Wheat yield in no till and organic systems was reduced by 10% and 30% compared to conventional systems. Bulk density was higher in no-till than in ploughed fields in the 5-20 cm layer but similar in the subsoil. A strong stratification with depth of nutrients and soil organic carbon was observed in no-till fields. No-till and organic fields showed larger soil aggregates and higher microbial biomass in the surface layer (0-5 cm). Mycorrhizal colonisation of wheat roots was on average 50% higher in organic fields. However, no differences in carbon stock in the 0-20 cm layer was observed and the ratio organic matter / clay shows a high variability (from poor to good) and was not dependent on the farming system.Our results show that an improvement of soil properties can be achieved with alternative cropping practices such as no-till and organic farming, but also depends on the other practices adopted by the farmers, such as input of organic amendments, crop rotation diversification, residue management

ECOLOGICAL SIGNIFICANCE OF NITRIFIER AND DENITRIFIER SPATIAL PATTERNS IN THREE ARCTIC ECOSYSTEMS

Owing to spatial variability of soil properties, microbial communities and their functional role in biogeochemical processes may also vary across multiple spatial scales. Soil and microbial spatial heterogeneity has been studied in various tropical and temperate ecosystems yet no information is available from Arctic permafrost ecosystems. These ecosystems represent a significant proportion of global land mass and contain about one fourth of total soil carbon pool. Soil microbial N transformations such as nitrification and denitrification have significant implications for N availability and N loss in nutrient-limited Arctic ecosystems. This study aims to elucidate 1) the spatial variability of soil attributes and the overall microbial communities 2) the spatial structure of ammonia oxidizer and denitrifier abundance and their activities, and 3) relationships among microbial communities, functional processes, and soil attributes in three Arctic Cryosolic ecosystems. The results show that despite challenging climatic conditions and the regular occurrence of cryopedogenic processes, soil properties and microbial abundance are highly spatially dependent and their spatial autocorrelation is consistent within and between the ecohabitats. Despite similar abundances, the zone of spatial autocorrelation is substantially smaller than other ecosystems. The correlations between moisture content and other soil attributes in Arctic are considerably higher than temperate agricultural and tropical grassland soils, suggesting the critical role of moisture in Arctic soil ecosystems. Ammonia-oxidizing archaeal and bacterial communities and aerobic ammonia oxidation were spatially dependent. Functional groups were spatially structured within 4 m whereas biochemical processes were structured within 40 m. Ammonia oxidation was driven at small scales (<1 m) by moisture and total organic carbon content whereas gene abundance and other edaphic factors drove ammonia oxidation at medium (1-10 m) and large (10-100 m) scales. Denitrifier functional groups and potential denitrification were spatially autocorrelated within a scale of 5 m. Soil moisture, organic carbon and nitrogen content were the predominant driving factors with nirK abundance also correlated to potential denitrification. This is the first study to report high spatial dependence of soil properties, overall microbial, ammonia oxidizing, and denitrifying communities, and functional processes in Canadian Arctic. It disentangles the associations among the aforementioned parameters to identify the key controls on nitrification and denitrification in Cryosolic ecosystems

R & D incentives in vertically related industries

We study vertically related industry where both upstream and downstream producers conduct cost-reducing R&D. We find that R&D investments at the two levels of the market are strategic complements: R&D by films at one level benefit all firms at the other level. Furthermore, R&D by a downstream firm increases the demand for the intermediate good, thereby raising the input price for rival firms. Consequently downstream firms may invest more in R&D with increased downstream competition, a possibility that never arises in a purely horizontal set up. Increased competition in the upstream (downstream) market leads to more R&D investment by all downstream (upstream) firms. By internalizing the positive externalities between the two levels of the market, as well as the negative externalities among firms on the same level, R&D cooperation may either promote or hinder innovation, depending on the number of firms. Policy analysis based on purely horizontal R&D models may not accurately reflect the true social benefits and costs of R&D cooperation

Downstream R&D, raising rivals\u27 costs, and input price contract

We analyze the incentives for cost-reducing R&D by downstream firms in a two-tier market structure. Downstream R&D increases the demand for an input,thereb y allowing the upstream firm to raise the input price. While it lowers the benefit of R&D to a downstream firm,suc h a price adjustment by the input supplier leads to a higher production cost for all rival firms. Due to this “raising rivals’ cost” effect,a downstream oligopolist may invest more in R&D than does a downstream monopolist,a phenomenon that does not occur in a purely horizontal setting. Fixed-price agreements under which the input price remains unchanged in response to downstream R&D promote innovation by eliminating the opportunistic behavior of the input supplier. In general,the incentive for downstream R&D is positively related to input pricing rigidit

On the Estimation of the incidence and Prevalence in Two-Phase Longitudinal Sampling Design

Two-phase sampling design is a common practice in many medical studies. Generally, the first-phase classification is fallible but relatively cheap, while the accurate second phase state-of-the-art medical diagnosis is complex and rather expensive to perform. When constructed efficiently it offers great potential for higher true case detection as well as for higher precision at a limited cost. In this article, we consider epidemiological studies with two-phase sampling design. However, instead of a single two-phase study, we consider a scenario where a series of two-phase studies are done in a longitudinal fashion on a cohort of interest. Another major design issue is non-curable pattern of certain disease (e.g. Dementia, Alzheimer\u27s etc.). Thus often the identified disease positive subjects are removed from the original population under observation, as they require clinical attention, which is quite different from the yet unidentified group. In this article, we motivated our methodology development from two real-life studies. We consider efficient and simultaneous estimation of prevalence as well incidence at multiple time points from a sampling design-based approach. We have explicitly shown the benefit of our developed methodology for an elderly population with significant burden of home-health care usage and at the high risk of major depressive disorder

Environmental Regulation and Technological Innovation with Spillovers

We present a two-period dynamic model of standard setting under asymmetric information to model the attempts by the Califormia Air Resources Board (CARB) in getting car manufacturers to comply with its phase-in of stringent emissions standards. After CARB chooses an initial emissions standard that firms are required to comply with, automakers respond by choosing R&D investment and production levels which provide CARB an imperfect signal whether they are more or less capable of complying with the standard. CARB resets the environmental standard and the firms once again choose research and production levels. Firms are Cournot duopolists in the product market and can choose to do research noncooperatively or cooperatively in the presence of spillovers. We show that firms will behave strategically and underinvest in research both under competitive and cooperative R&D, though the level of underinvestment — the ratchet effect — is greater under cooperative R&D when spillovers are large. We uncover a fundamental conflict between the incentives of firms to do cooperative research and social welfare: that firms will want to engage in cooperative (resp. noncooperative) R&D only when spillovers are low (resp. high) while social welfare is greater under noncooperative (resp. cooperative) research

Efficacy of Delta Plate in Condylar Fracture: a Case Series With Review

Open reduction and internal fixation (ORIF) of mandibular condylar fracture with a three dimensional stabilization has been a controversial topic in oral and maxillofacial surgery. Miniplates and many 3D plates have been used till now for fixation of condylar fracture and delta plate is one of them. Present literature has less evidence about which one is superior over another. We have tried to evaluate the clinical performance of the delta miniplate in this study. A total of 10 patients presenting mandibular condylar fracture were treated by ORIF using delta miniplate. Dimensional details were measured of 10 dry human mandibles. At the end of 1-year follow-up period, all patients had satisfactory results, both clinically and radiologically. Delta plate showed better stability in the condylar region and less complication associated with plating system

An age-distributed immuno-epidemiological model with information-based vaccination decision

A new age-distributed immuno-epidemiological model with information-based vaccine uptake suggested in this work represents a system of integro-differential equations for the numbers of susceptible individuals, infected individuals, vaccinated individuals and recovered individuals. This model describes the influence of vaccination decision on epidemic progression in different age groups. We prove the existence and uniqueness of a positive solution using the fixed point theory. In a particular case of age-independent model, we determine the final size of epidemic, that is, the limiting number of susceptible individuals at asymptotically large time. Numerical simulations show that the information-based vaccine acceptance can significantly influence the epidemic progression. Though the initial stage of epidemic progression is the same for all memory kernels, as the epidemic progresses and more information about the disease becomes available, further epidemic progression strongly depends on the memory effect. Short-range memory kernel appears to be more effective in restraining the epidemic outbreaks because it allows for more responsive and adaptive vaccination decisions based on the most recent information about the disease

An age-Dependent Immuno-Epidemiological Model With Distributed Recovery and Death Rates

The work is devoted to a new immuno-epidemiological model with distributed recovery and death rates considered as functions of time after the infection onset. Disease transmission rate depends on the intra-subject viral load determined from the immunological submodel. The age-dependent model includes the viral load, recovery and death rates as functions of age considered as a continuous variable. Equations for susceptible, infected, recovered and dead compartments are expressed in terms of the number of newly infected cases. The analysis of the model includes the proof of the existence and uniqueness of solution. Furthermore, it is shown how the model can be reduced to age-dependent SIR or delay model under certain assumptions on recovery and death distributions. Basic reproduction number and final size of epidemic are determined for the reduced models. The model is validated with a COVID-19 case data. Modelling results show that proportion of young age groups can influence the epidemic progression since disease transmission rate for them is higher than for other age groups