Solving higher-dimensional continuous time stochastic control problems by value function regression

The paper develops a method to solve higher-dimensional stochasticcontrol problems in continuous time. A finite difference typeapproximation scheme is used on a coarse grid of low discrepancypoints, while the value function at intermediate points is obtainedby regression. The stability properties of the method are discussed,and applications are given to test problems of up to 10 dimensions.Accurate solutions to these problems can be obtained on a personalcomputer.

Drug innovation, prices and health

This article tries to reconcile economic-industrial policy with health policy when dealing with biomedical innovation and welfare state sustainability. Better health accounts for an increasingly large proportion of welfare improvements. Explanation is given to the welfare losses coming from the fact than industrial and health policy tend to ignore each other. Drug s prices reflecting their relative relative effectiveness send the right signal to the industry rewarding innovation with impact on quantity and quality of life- and to the buyers of health care services.The level of drug s public reimbursement indicates the social willingness to pay of the different national health systems, not only by means of inclusion, or rejection, in the basket of services covered, but especially establishing the proportion of the price that is going to be financed publicly.Reference pricing for therapeutic equivalents as the upper limit of the social willingness to pay- and two-tiered co-payments for users (avoidable and inversely related with the incremental effectiveness of de drug) are deemed appropriate for those countries concerned at the same time with increasing their productivity and maintaining its welfare state. Profits drive R&D but not its location. There is no intrinsic contradiction between high productivity and a consolidated National Health Service (welfare state) as the European Nordic Countries are telling us every day.

Lobbying, innovation and protectionist cycles

This paper explains why trade liberalizations occur in developing countries,and why they are often reversed. It does so by focusing on the use oflobbying for protection by import competing firms as a means to postponecostly product quality upgrades to keep up with foreign competitors. Giventhe availability of a political market for import tariffs, domestic firmswill lobby for a sequence of tariffs that insulate domestic profits from awidening quality gap, thereby allowing adjustment to be postponed. But asthe contributions required by the government grow with the size of thequality gap, it will be optimal to adjust quality and to decrease thelobbying effort at some time, leading to liberalization and technologicalcatch-up. But then the equilibrium tariff will again be small and "cheap",and it will pay to start lobbying anew, until the next quality adjustment.Therefore, cycles in protection will occur as a result of the use oflobbying as a substitute for innovation. The model thus sheds new light onthe impact of the costs of protection on the effectiveness of the lobbyingeffort over time, and on their implications for the timing and the timehorizon of trade reforms in developing countries.

Entrepreneurial risk, investment and innovation

In this paper I develop a general equilibrium model with risk averse entrepreneurialfirms and with public firms. The model predicts that an increase in uncertainty reducesthe propensity of entrepreneurial firms to innovate, while it does not affect thepropensity of public firms to innovate. Furthermore, it predicts that the negativeeffect of uncertainty on innovation is stronger for the less diversified entrepreneurialfirms, and is stronger in the absence of financing frictions in the economy. In thesecond part of the paper I test these predictions on a dataset of small and mediumItalian manufacturing firms.

Neglected risks, financial innovation and financial fragility

We present a standard model of financial innovation, in which intermediaries engineer securities with cash flows that investors seek, but modify two assumptions. First, investors (and possibly intermediaries) neglect certain unlikely risks. Second, investors demand securities with safe cash flows. Financial intermediaries cater to these preferences and beliefs by engineering securities perceived to be safe but exposed to neglected risks. Because the risks are neglected, security issuance is excessive. As investors eventually recognize these risks, they fly back to safety of traditional securities and markets become fragile, even without leverage, precisely because the volume of new claims is excessive.

Diversity of Calliphoridae and Sarcophagidae (Diptera, Oestroidea) in continuous forest and gaps at different stages of regeneration in the Urucu oilfield in western Brazilian Amazonia

Diversity of Calliphoridae and Sarcophagidae (Diptera, Oestroidea) in continuous forest and gaps at different stages of regeneration in the Urucu oilfield in western Brazilian Amazonia. The diversity of Calliphoridae and Sarcophagidae in continuous forest and gaps at different stages of regeneration was studied in the Urucu river basin, in Coari, state of Amazonas, Brazil. The flies were collected at 16 sampling points, 12 in gaps at different stages of regeneration (early _ C1, mid- C2 and late successional _ C3) and four in continuous forest _ MT. The diversity of blowflies was similar in the two less regenerated habitats (C1 and C2), and lower than that in the late successional (C3) and continuous forests (MT). By contrast, the diversity of flesh flies was much higher in all three types of gaps (C1, C2 and C3) in comparison with continuous forest (MT). Ordination (NMDS) and similarity (ANOSIM) analyses revealed that the blowflies communities were grouped by habitat type, which affected species composition more than diversity. Analysis of the flesh flies revealed two main groupings, gaps (C1, C2 and C3) and continuous forest (MT), with no evidence of any influence of successional stage on the diversity of the community.

Complementarity between technology make and buy in innovation strategies: Evidence from Belgiam manufacturing firms

This paper characterizes the innovation strategy of manufacturing firms andexamines the relation between the innovation strategy and importantindustry-, firm- and innovation-specific characteristics using Belgiandata from the Eurostat Community Innovation Survey. In addition to importantsize effects explaining innovation, we find that high perceived risks andcosts and low appropriability of innovations do not discourage innovation,but rather determine how the innovation sourcing strategy is chosen. Withrespect to the determinants of the decision of the innovative firm toproduce technology itself (Make) or to source technology externally (Buy),we find that small firms are more likely restrict their innovation strategyto an exclusive make or buy strategy, while large firms are more likely tocombine both internal and external knowledge acquisition in their innovationstrategy. An interesting result that highlights the complementary nature ofthe Make and Buy decisions, is that, controlled for firm size, companies forwhich internal information is an important source for innovation are morelikely to combine internal and external sources of technology. We find thisto be evidence of the fact that in-house R&D generates the necessaryabsorptive capacity to profit from external knowledge acquisition. Also theeffectiveness of different mechanisms to appropriate the benefits ofinnovations and the internal organizational resistance against change areimportant determinants of the firm's technology sourcing strategy.

Employment protection, international specialization and innovation

We develop a model to analyse the implications of firing costs on incentivesfor R&D and international specialization. The Key idea is paying the firingcost, the country with a rigid labor market will tend to produce relativelysecure goods, at a late stage of their product life cycle.Under international trade, an international product cycle emerges where,roughly, new goods are first produced in the low firing cost country willspecialize in 'secondary innovations', that is, improvements in existinggoods, while the low firing cost country will more specialize in 'primaryinnovation', that is, invention of new goods.

Variability of resting energy expenditure in healthy volunteers during fasting and continuous enteral feeding.

The magnitude of variability in resting energy expenditure (REE) during the day was assessed in nine healthy young subjects under two nutritional conditions: 1) mixed nutrient (53% carbohydrate, 30% fat, 17% protein) enteral feeding at an energy level corresponding to 1.44 REE; and 2) enteral fasting, with only water allowed. In each subject, six 30-min measurements of REE were performed using indirect calorimetry (hood system) at 90-min intervals from 9 AM to 5 PM. The mean REE and respiratory quotient were significantly (p less than .01) greater during feeding than during fasting (1.08 +/- 0.07 [SEM] vs. 1.00 +/- 0.06 kcal/min and 0.874 +/- 0.007 vs. 0.829 +/- 0.008 kcal/min, respectively). Mean postprandial thermogenesis was 4.9 +/- 0.4% of metabolizable energy administered. The intraindividual variability of REE throughout the day, expressed as the coefficient of variation, ranged from 0.7% to 2.0% in the fasting condition and from 1.2% to 4.1% in the feeding condition. There was no significant difference between the REE measured in the morning and that determined in the afternoon.

Ignoring information in binary choice with continuous variables: When is less 'more'?

When can a single variable be more accurate in binary choice than multiple sources of information? We derive analytically the probability that a single variable (SV) will correctly predict one of two choices when both criterion and predictor are continuous variables. We further provide analogous derivations for multiple regression (MR) and equal weighting (EW) and specify the conditions under which the models differ in expected predictive ability. Key factors include variability in cue validities, intercorrelation between predictors, and the ratio of predictors to observations in MR. Theory and simulations are used to illustrate the differential effects of these factors. Results directly address why and when one-reason decision making can be more effective than analyses that use more information. We thus provide analytical backing to intriguing empirical results that, to date, have lacked theoretical justification. There are predictable conditions for which one should expect less to be more.

Translation to success of surgical innovation.

Contemporary thoracic and cardiovascular surgery uses extensive equipment and devices to enable its performance. As the specialties develop and new frontiers are crossed, the technology needs to advance in a parallel fashion. Strokes of genius or problem-solving brain-storming may generate great ideas, but the metamorphosis of an idea into a physical functioning tool requires a lot more than just a thinking process. A modern surgical device is the end-point of a sophisticated, complicated and potentially treacherous route, which incorporates new skills and knowledge acquisition. Processes including technology transfer, commercialisation, corporate and product development, intellectual property and regulatory routes all play pivotal roles in this voyage. Many good ideas may fall by the wayside for a multitude of reasons as they may not be marketable or may be badly marketed. In this article, we attempt to illuminate the components required in the process of surgical innovation, which we believe must remain in the remit of the modern-day thoracic and cardiovascular surgeon.

Continuous arterial spin labeling of mouse cerebral blood flow using an actively-detuned two-coil system at 9.4T.

Among numerous magnetic resonance imaging (MRI) techniques, perfusion MRI provides insight into the passage of blood through the brain's vascular network non-invasively. Studying disease models and transgenic mice would intrinsically help understanding the underlying brain functions, cerebrovascular disease and brain disorders. This study evaluates the feasibility of performing continuous arterial spin labeling (CASL) on all cranial arteries for mapping murine cerebral blood flow at 9.4 T. We showed that with an active-detuned two-coil system, a labeling efficiency of 0.82 ± 0.03 was achieved with minimal magnetization transfer residuals in brain. The resulting cerebral blood flow of healthy mouse was 99 ± 26 mL/100g/min, in excellent agreement with other techniques. In conclusion, high magnetic fields deliver high sensitivity and allowing not only CASL but also other MR techniques, i.e. (1)H MRS and diffusion MRI etc, in studying murine brains.

Un nuevo muestreador de huevos de peces pelagicos a bordo del BIC Jose Olaya Balandra: CUFES (Continuous Underway y Fish egg Sampler)

El IMARPE cuenta con un nuevo muestreador de huevos de peces pelágicos, con características diferentes aquéllas de las redes convencionales.

Minimal data requirements for a continuous monitoring of the quality of care using the DRG classification.

The DRG classification provides a useful tool for the evaluation of hospital care. Indicators such as readmissions and mortality rates adjusted for the hospital Casemix could be adopted in Switzerland at the price of minor additions to the hospital discharge record. The additional information required to build patients histories and to identify the deaths occurring after hospital discharge is detailed.

Saturable metabolism of continuous high-dose ifosfamide with mesna and GM-CSF: a pharmacokinetic study in advanced sarcoma patients. Swiss Group for Clinical Cancer Research (SAKK).

BACKGROUND: The aim of this study was to assess the pharmacology, toxicity and activity of high-dose ifosfamide mesna +/- GM-CSF administered by a five-day continuous infusion at a total ifosfamide dose of 12-18 g/m2 in adult patients with advanced sarcomas. PATIENTS AND METHODS: Between January 1991 and October 1992 32 patients with advanced or metastatic sarcoma were entered the study. Twenty-seven patients were pretreated including twenty-three with prior ifosfamide at less than 8 g/m2 total dose/cycle. In 25 patients (27 cycles) extensive pharmacokinetic analyses were performed. RESULTS: The area under the plasma concentration-time curve (AUC) for ifosfamide increased linearly with dose while the AUC's of the metabolites measured in plasma by thin-layer chromatography did not increase with dose, particularly that of the active metabolite isophosphoramide mustard. Furthermore the AUC of the inactive carboxymetabolite did not increase with dose. Interpatient variability of pharmacokinetic parameters was high. Dose-limiting toxicity was myelosuppression at 18 g/m2 total dose with grade 4 neutropenia in five of six patients and grade 4 thrombocytopenia in four of six patients. Therefore the maximum tolerated dose was considered to be 18 g/m2 total dose. There was one CR and eleven PR in twenty-nine evaluable patients (overall response rate 41%). CONCLUSION: Both the activation and inactivation pathways of ifosfamide are non-linear and saturable at high-doses although the pharmacokinetics of the parent drug itself are dose linear. Ifosfamide doses greater than 14-16 g/m2 per cycle appear to result in a relative decrease of the active metabolite isophosphoramide mustard. These data suggest a dose-dependent saturation or even inhibition of ifosfamide metabolism by increasing high dose ifosfamide and suggest the need for further metabolic studies.