730 research outputs found
The optimal behaviour of firms facing stochastic costs
This paper aims at assessing the optimal behavior of a firm facing stochastic costs of production. In an imperfectly competitive setting, we evaluate to what extent a firm may decide to locate part of its production in other markets different from which it is actually settled. This decision is taken in a stochastic environment. Portfolio theory is used to derive the optimal solution for the intertemporal profit maximization problem. In such a framework, splitting production between different locations may be optimal when a firm is able to charge different prices in the different local markets.Firm behaviour, Portfolio theory, Risk aversion, Uncertainty.
multibody simulation of a small size farming tracked vehicle
Abstract In this paper, the Multibody (MTB) model of a small size tracked vehicle for farming applications is shown. These machines may encounter several working scenarios in their operating life when equipped with different working tools. Moreover, they are used in unstructured environments that are very difficult to predict in terms of terrain conditions and slope. Depending on these factors, the actual tractive force may vary a lot requiring often a high number of field tests to qualify the vehicle performance. The numerical model built in MSC ADAMS, wants to be a software environment where several working conditions can be exploited considering the dynamic properties of the vehicle. This work focuses on the global kinematic behavior, considering the difference between imposed motion laws and the actual one
Un \u201cdialogo\u201d possibile? Riflessioni comparative sulla dialettica corti-legislatore nella prospettiva della giurisdizione costituzionale \u201cmutilata\u201d della Norvegia
Dopo aver illustrato il contributo della comparazione giuridica nelle indagini sul \u2018dialogo\u2019 tra corti e legislatori, il contributo si concentra sulle inevitabili tensioni che oppongono la giurisdizione costituzionale al potere democraticamente legittimato. Di qui si esamina la natura non-maggioritaria e anti-maggioritaria del conflitto che oppone corti e legislatori. Infine, ci si sofferma sul caso norvegese, dove il controllo di costituzionalit\ue0 \ue8 indagato nelle sue numerose particolarit\ue0
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Spinning Loop Black Holes
In this paper we construct four Kerr-like spacetimes starting from the loop
black hole Schwarzschild solutions (LBH) and applying the Newman-Janis
transformation. In previous papers the Schwarzschild LBH was obtained replacing
the Ashtekar connection with holonomies on a particular graph in a
minisuperspace approximation which describes the black hole interior. Starting
from this solution, we use a Newman-Janis transformation and we specialize to
two different and natural complexifications inspired from the complexifications
of the Schwarzschild and Reissner-Nordstrom metrics. We show explicitly that
the space-times obtained in this way are singularity free and thus there are no
naked singularities. We show that the transformation move, if any, the
causality violating regions of the Kerr metric far from r=0. We study the
space-time structure with particular attention to the horizons shape. We
conclude the paper with a discussion on a regular Reissner-Nordstrom black hole
derived from the Schwarzschild LBH and then applying again the Newmann-Janis
transformation.Comment: 18 pages, 18 figure
Evaluation of antioxidant supplementation in must on the development and potential reduction of different compounds involved in atypical ageing of wine using HPLC-HRMS
Atypical aging of white wines (ATA) is an off-flavour characterised by rapid loss of fruity aromas and the development of unpleasant odours. This study aims to evaluate the effectiveness of different oenological adjuvants (4-ethylcatechol, 4-methylcatechol, gentisic acid, hydroxytyrosol, ascorbic acid, glutathione, ellagic acid, gallic acid, galla tannin, ellagic tannin, quebracho, grape tannins) added to musts before fermentation for preventing the possible development of ATA. High resolution mass spectrometry made it possible to quantify and qualify free and conjugated IAA in wine at the end of the fermentation and subsequently 2-aminoacetophenone (AAP) was quantified after the force ageing period (6 days at 40 °C). Ascorbic acid was confirmed as the most appropriate antioxidant adjuvant which can be used for ATA defect prevention. With an almost comparable effect, gallotannin addition prevented AAP production to exceed 1 μg/L. A predicted model (ANCOVA) indicated that over 80% of the variability of potential AAP formation in wines was explained by the amount of precursors, grape variety and antioxidant treatment. Moreover, a suspect screening approach made it possible to study the kinetic formation and the consumption of the reaction metabolites formed during the oxidative degradation of IAA leading to AA
Treatment of forearm fractures in children and adolescents
OBJECTIVE: The treatment and the angular deviations tolerated in diaphyseal forearm fractures in children evoke divergent opinions in literature. In view of this controversy, we idealized this study to evaluate the preferred treatment methods for this injury, during the 39th Brazilian Congress on Orthopedics and Traumatology. METHODS: A total 759 questionnaires were answered (13% of total entrants). We addressed the general aspects of the study sample to obtain a profile of the orthopedic surgeons questioned. RESULTS: Two clinical subjects were presented, aged 12 (CASE 1) and 5 years old (CASE 2), along with radiographs depicting forearm diaphyseal fractures of these patients. Data was gathered and submitted to statistical analysis. The overall preferred treatment in CASE 1 was closed reduction and fixation with Kirschner wires (26%), while in case 2 it was closed reduction followed by plaster cast (46%). CONCLUSION: Among orthopedic surgeons less than 30 years old, the choice for less invasive treatments and greater acceptance of angular values prevailed in both cases. The traumatologists accepted lower angular values and tended towards more invasive treatments, particularly for CASE 2. On the other hand, the pediatric orthopedic surgeon prefers less invasive treatments and accepts greater angular deviations.OBJETIVO: O tratamento e os desvios angulares tolerados nas fraturas diafisárias do antebraço em crianças evoca opiniões divergentes na literatura. Frente a esta indefinição, idealizamos este trabalho com o objetivo de avaliar transversalmente os métodos terapêuticos preferenciais para esta lesão durante o 39º Congresso Brasileiro de Ortopedia e Traumatologia. MÉTODO: Foram respondidos 759 questionários (13% do total de inscritos). Abordamos os aspectos gerais da amostra estudada para traçar o perfil do ortopedista questionado. Foram expostas duas situações clÃnicas em indivÃduos de 12 (CASO 1) e 5 anos (CASO 2), sendo apresentadas radiografias com fraturas do antebraço destes pacientes. Os dados obtidos foram compilados e submetidos à análise estatÃstica. RESULTADO: O tratamento mais indicado no CASO 1 foi redução incruenta e fixação com fios de Kirschner (26%), enquanto no CASO 2 foi redução incruenta seguida de aparelho gessado (46%). CONCLUSÃO: Entre os ortopedistas com menos de 30 anos, a escolha por tratamentos menos invasivos e aceitação de maiores angulações prevaleceu para ambos os casos. Os traumatologistas aceitam menor angulação e tendem aos tratamentos invasivos, particularmente para o CASO 2. Já o ortopedista pediátrico opta por tratamentos menos invasivos e aceita maiores desvios angulares.Universidade Federal de São Paulo (UNIFESP) Departamento de Ortopedia e TraumatologiaUNIFESP, Depto. de Ortopedia e TraumatologiaSciEL
The optimal behaviour of firms facing stochastic costs
This paper aims at assessing the optimal behavior of a firm facing stochastic costs of production. In an imperfectly competitive setting, we evaluate to what extent a firm may decide to locate part of its production in other markets different from which it is actually settled. This decision is taken in a stochastic environment. Portfolio theory is used to derive the optimal solution for the intertemporal profit maximization problem. In such a framework, splitting production between different locations may be optimal when a firm is able to charge different prices in the different local markets
Long-Term Outcomes of Conventional Aortic Valve Replacement in High-Risk Patients: Where Do We Stand?
Purpose: The introduction of transcatheter aortic valves has focused attention on the
results of conventional aortic valve surgery in high-risk patients. The aim of the study was
to evaluate 5-years outcomes in this category of patients in the current surgical era.
Methods: This is an observational retrospective study of 581 high-risk patients undergoing
aortic valve replacement from 2008 to 2013, with a mean logistic EuroSCORE of 26.6% ±
14.6%. Data were prospectively collected in a database of Emilia-Romagna region (Italy).
Results: Overall 30-day mortality was 9.3%. Stroke rate was 1.5%. At 1-, 3-, and 5-years
overall mortality was 18.2%, 30.4%, and 42.2%, cardiac death rate was 3.9%, 9.2%, and
12.9%, stroke rate 2.5%, 7.7%, and 10.2%, re-operation occurrence 0.2%, 0.9% and
1.3%, and new pacemaker implantation was 2.3%, 5.1% and 7.8%. At multivariate analysis,
urgency, hemodynamic instability, LVEF ≤30%, NYHA III-IV, severe chronic
obstructive pulmonary disease (COPD), extra-cardiac arteriopathy, cerebrovascular disease,
and creatinine >2.0 mg/dL remained independent predictors of 5-year mortality.
Conclusion: The results of the current study add weight to the evidence that traditional
aortic valve replacement can be performed in high-risk patients with satisfactory 5-year
mortality and morbidity. Our study may help to improve decision-making in this category
of high-risk patients with aortic valve disease
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