Curve crossing for the reflected Levy process at zero and infinity

Let $R_{t}=\sup_{0\leq s\leq t}X_{s}-X_{t}$ be a Levy process reflected in its maximum. We give necessary and sufficient conditions for finiteness of passage times above power law boundaries at infinity. Information as to when the expected passage time for $R_{t}$ is finite, is given. We also discuss the almost sure finiteness of $\limsup_{t\to 0}R_{t}/t^{\kappa}$, for each $\kappa\geq 0$.

Analysis of Direct Outdoor Air Cooling Efficency for Combined Variable Air Volume Air-conditioning System in Stores in Cold Climates of China

Direct outdoor air cooling contributes a lot not only to the improvement of the indoor air quality but also to the energy saving. Its full use will reduce the water chiller’s running time especially in some stores where cooling load keeps much higher and longer than that in other buildings. A novel air-conditioning system named Combined Variable Air Volume system (CVAV), combining a normal AHU with a separate outdoor air supply system, was proposed firstly by the authors. The most attractive feature of the system is its full utilization of cooling capacity and freshness of outdoor air in the transition period of the year round. On the basis of the obtain of the dynamic cooling loads of the typical shopping malls in different four cities located in cold climates in China with the aid of DOE-2, the possibility of increasing the amount of outdoor air volume of CVAV system in the transition period instead of operating the water chillers was confirmed. Moreover, a new concept, Direct Outdoor Air Cooling Efficiency (DOACE), was defined as the ratio of cooling capacity of outdoor air to the water chiller, indicating the degree of outdoor air’s utilization. And the DOACE of the CVAV was calculated and compared with that of conventional all-air constant volume air-conditioning systems, the results showed that CVAV bear much more energy saving potential with the 10%~19% higher DOACE and it is a kind of energy efficient systems and can improve the indoor air quality as well.

The Carnegie curve

The Earth’s fair weather atmospheric electric field shows, in clean air, an average daily variation which follows universal time, globally independent of the measurement position. This single diurnal cycle variation (maximum around 19UT and minimum around 03UT) is widely known as the Carnegie curve, after the geophysical survey vessel of the Carnegie Institution of Washington on which the original measurement campaigns demonstrating the universal time variation were undertaken. The Carnegie curve’s enduring importance is in providing a reference variation against which atmospheric electricity measurements are still compared; it is believed to originate from regular daily variations in atmospheric electrification associated with the different global disturbed weather regions. Details of the instrumentation, measurement principles and data obtained on the Carnegie’s seventh and final cruise are reviewed here, also deriving new harmonic coefficients allowing calculation of the Carnegie curve for different seasons. The additional harmonic analysis now identifies changes in the phasing of the maximum and minimum in the Carnegie curve, which shows a systematic seasonal variation, linked to the solstices and equinoxes, respectively.

The M curve and the performance of Spanish international new ventures

In this paper we address three challenges. First, we discuss how international new ventures (INVs) are probably not explained by the Uppsala model as there is no time for learning about foreign markets in newly born and small firms. Only in the longer term can INVs develop experiential learning to overcome the liability of foreignness as they expand abroad. Second, we advance theoretically on previous research demonstrating that the multinationality−performance relationship of INVs follows a traditional S-shaped relationship, but they first experience a ‘born global illusion’ which leads to a non-traditional M curve. Third, using a panel data analysis for the period 1994–2008 we find empirically that Spanish INVs follow an inverted U curve in the very short term, where no learning takes place, but that experience gained over time yields an M-curve relationship once learning takes place.

Chronic low frequency/low volume resistance training reduces pro-inflammatory cytokine protein levels and TLR4 mRNA in rat skeletal muscle

Skeletal muscle is the source of pro- and anti-inflammatory cytokines, and recently, it has been recognized as an important source of interleukin 6 (IL-6), a cytokine that exerts inhibitory effects on several pro-inflammatory cytokines. Although dynamic chronic resistance training has been shown to produce the known ""repeated bout effect"", which abolishes the acute muscle damage, performing of high-intensity resistance training has been regarded highly advisable, at least from the hypertrophy perspective. On the other hand, a more therapeutic, ""non-damaging"" resistance training program, mainly composed of concentric forces, low frequency/low volume of training, and the same exercise, could theoretically benefit the muscle when the main issue is to avoid muscle inflammation (as in the treatment of several ""low-grade"" inflammatory diseases) because the acute effect of each resistance exercise session could be diminished/avoided, at the same time that the muscle is still being overloaded in a concentric manner. However, the benefits of such ""less demanding"" resistance training schedule on the muscle inflammatory profile have never been investigated. Therefore, we assessed the protein expression of IL-6, TNF-alpha, IL-10, IL-10/TNF-alpha ratio, and HSP70 levels and mRNA expression of SCF(beta-TrCP), IL-15, and TLR-4 in the skeletal muscle of rats submitted to resistance training. Briefly, animals were randomly assigned to either a control group (S, n = 8) or a resistance-trained group (T, n = 7). Trained rats were exercised over a duration of 12 weeks (two times per day, two times per week). Detection of IL-6, TNF-alpha, IL-10, and HSP70 protein expression was carried out by western blotting and SCF(beta-TrCP) (SKP Cullin F-Box Protein Ligases), a class of enzymes involved in the ubiquitination of protein substrates to proteasomal degradation, IL-15, and TLR-4 by RT-PCR. Our results show a decreased expression of TNF-alpha and TLR4 mRNA (40 and 60%, respectively; p < 0.05) in the plantar muscle from trained, when compared with control rats. In conclusion, exercise training induced decreased TNF-alpha and TLR-4 expressions, resulting in a modified IL-10/TNF-alpha ratio in the skeletal muscle. These data show that, in healthy rats, 12-week resistance training, predominantly composed of concentric stimuli and low frequency/low volume schedule, down regulates skeletal muscle production of cytokines involved in the onset, maintenance, and regulation of inXammation.

On ""Schwinger mechanism for gluon pair production in the presence of arbitrary time dependent chromo-electric field""

Recently the paper ""Schwinger mechanism for gluon pair production in the presence of arbitrary time dependent chromo-electric field"" by G. C. Nayak was published [Eur. Phys. J. C 59: 715, 2009; arXiv:0708.2430]. Its aim is to obtain an exact expression for the probability of non-perturbative gluon pair production per unit time per unit volume and per unit transverse momentum in an arbitrary time-dependent chromo-electric background field. We believe that the obtained expression is open to question. We demonstrate its inconsistency on some well-known examples. We think that this is a consequence of using the socalled ""shift theorem""[arXiv:hep-th/0609192] in deriving the expression for the probability. We make some critical comments on the theorem and its applicability to the problem in question.

U-curve: A branch-and-bound optimization algorithm for U-shaped cost functions on Boolean lattices applied to the feature selection problem

This paper presents the formulation of a combinatorial optimization problem with the following characteristics: (i) the search space is the power set of a finite set structured as a Boolean lattice; (ii) the cost function forms a U-shaped curve when applied to any lattice chain. This formulation applies for feature selection in the context of pattern recognition. The known approaches for this problem are branch-and-bound algorithms and heuristics that explore partially the search space. Branch-and-bound algorithms are equivalent to the full search, while heuristics are not. This paper presents a branch-and-bound algorithm that differs from the others known by exploring the lattice structure and the U-shaped chain curves of the search space. The main contribution of this paper is the architecture of this algorithm that is based on the representation and exploration of the search space by new lattice properties proven here. Several experiments, with well known public data, indicate the superiority of the proposed method to the sequential floating forward selection (SFFS), which is a popular heuristic that gives good results in very short computational time. In all experiments, the proposed method got better or equal results in similar or even smaller computational time. (C) 2009 Elsevier Ltd. All rights reserved.

Sequential injection analysis (SIA) and response surface methodology: A versatile small volume approach for optimization of photo-Fenton processes

Optimization of photo-Fenton degradation of copper phthalocyanine blue was achieved by response surface methodology (RSM) constructed with the aid of a sequential injection analysis (SIA) system coupled to a homemade photo-reactor. Highest degradation percentage was obtained at the following conditions [H(2)O(2)]/[phthalocyanine] = 7, [H(2)O(2)]/[FeSO(4)] = 10, pH = 2.5, and stopped flow time in the photo reactor = 30 s. The SIA system was designed to prepare a monosegment containing the reagents and sample, to pump it toward the photo-reactor for the specified time and send the products to a flow-through spectrophotometer for monitoring the color reduction of the dye. Changes in parameters such as reagent molar ratios. residence time and pH were made by modifications in the software commanding the SI system, without the need for physical reconfiguration of reagents around the selection valve. The proposed procedure and system fed the statistical program with degradation data for fast construction of response surface plots. After optimization, 97% of the dye was degraded. (C) 2009 Elsevier B.V. All rights reserved.

Daily Calls Volume Forecasting

A massive amount has been written about forecasting but few articles are written about the development of time series models of call volumes for emergency services. In this study, we use different techniques for forecasting and make the comparison of the techniques for the call volume of the emergency service Rescue 1122 Lahore, Pakistan. For the purpose of this study data is taken from emergency calls of Rescue 1122 from 1st January 2008 to 31 December 2009 and 731 observations are used. Our goal is to develop a simple model that could be used for forecasting the daily call volume. Two different approaches are used for forecasting the daily call volume Box and Jenkins (ARIMA) methodology and Smoothing methodology. We generate the models for forecasting of call volume and present a comparison of the two different techniques.

Real-Time Control Of Floods Along The Demer River, Belgium, By Means Of MPC In Combination With GA And A Fast Conceptual River Model

Climate model projections show that climate change will further increase the risk of flooding in many regions of the world. There is a need for climate adaptation, but building new infrastructure or additional retention basins has its limits, especially in densely populated areas where open spaces are limited. Another solution is the more efficient use of the existing infrastructure. This research investigates a method for real-time flood control by means of existing gated weirs and retention basins. The method was tested for the specific study area of the Demer basin in Belgium but is generally applicable. Today, retention basins along the Demer River are controlled by means of adjustable gated weirs based on fixed logic rules. However, because of the high complexity of the system, only suboptimal results are achieved by these rules. By making use of precipitation forecasts and combined hydrological-hydraulic river models, the state of the river network can be predicted. To fasten the calculation speed, a conceptual river model was used. The conceptual model was combined with a Model Predictive Control (MPC) algorithm and a Genetic Algorithm (GA). The MPC algorithm predicts the state of the river network depending on the positions of the adjustable weirs in the basin. The GA generates these positions in a semi-random way. Cost functions, based on water levels, were introduced to evaluate the efficiency of each generation, based on flood damage minimization. In the final phase of this research the influence of the most important MPC and GA parameters was investigated by means of a sensitivity study. The results show that the MPC-GA algorithm manages to reduce the total flood volume during the historical event of September 1998 by 46% in comparison with the current regulation. Based on the MPC-GA results, some recommendations could be formulated to improve the logic rules.

Influência do modo ventilatório no desempenho funcional dos enxertos pulmonares pós-transplante em modelo canino : ventilção controlada a volume versus ventilação controlada a pressão

O conhecimento dos riscos e conseqüências da lesão pulmonar induzida pela ventilação mecânica mudou a filosofia da terapia respiratória e tem influenciado nas recomendações e padronizações de seu uso. A influência dos diferentes modos ventilatórios não tem sido estudada em transplante de pulmão. O presente estudo teve como objetivo comparar a influência da ventilação controlada a volume (VCV) com a ventilação controlada a pressão (PCV) no desempenho funcional dos enxertos pulmonares, em modelo canino de transplante pulmonar unilateral utilizando-se doadores após três horas de parada cardiocirculatória. Quinze cães foram randomizados em dois grupos: oito cães foram alocados para o Grupo VCV e sete cães para o Grupo PCV. Cinco cães não completaram o período de avaliação pós-transplante, os dez animais restantes, grupo VCV (n= 5) e grupo PCV (n=5), foram avaliados durante 360 min após o término do transplante pulmonar. O desempenho funcional dos enxertos foi estudado através da avaliação da mecânica respiratória, trocas gasosas e das alterações histopatológicas. Não foram encontradas diferenças significativas em nenhuma das variáveis da mecânica respiratória estudadas (pressões de pico inspiratória- PPI; pressões de platô- PPLAT ; pressões médias de vias aéreas – Pmédia; complacências dinâmica- Cdyn e estática- Cst); da oxigenação, pressão parcial de oxigênio no sangue arterial e venoso misto (PaO2, PvO2); a diferença entre a saturação da hemoglobina no sangue arterial e no sangue venoso misto (ΔSO2); a pressão parcial de dióxido de carbono no sangue arterial e no sangue venoso misto (PaCO2, PvO2). As alterações histopatológicas encontradas nos pulmões dos animais foram compatíveis com o padrão de lesão pulmonar aguda. As alterações histológicas de padrão inespecífico não tiveram nenhuma correlação com o modo ventilatório. Este estudo demonstra que os modos ventilatórios estudados não influenciam as respostas dos enxertos pulmonares à lesão de isquemia reperfusão que se estabelece precocemente neste modelo experimental até 6 horas de reperfusão pulmonar pós-transplante unilateral.

A influência do volume na performance dos fundos de investimento em ações no Brasil

Tendo como base a literatura internacional sobre fundos mútuos, o presente estudo busca encontrar algumas características que influenciam a performance dos fundos de investimentos em ações no Brasil de janeiro de 1999 até abril de 2005. O objetivo principal do trabalho é perceber se os fundos de investimento em ações têm retorno decrescente de escala. Ao mesmo tempo, sabe-se que a persistência de uma boa rentabilidade depende do grau de profissionalismo dos gestores e também de uma boa relação entre o gestor responsável e o investidor e, um contrato ótimo entre ambos. Observou-se que o volume não tem influência negativa no retorno do fundo, pelo contrário, quanto maior o fundo melhor é a rentabilidade do mesmo. Os resultados também apresentaram que os fundos que cobram taxa de performance têm um desempenho melhor do que os que não cobram. Foi identificado também que os fundos que utilizam a marca d água como incentivo de remuneração aos gestores têm rentabilidade um pouco maior do que os fundos que pagam taxa de performance, mas não utilizam a marca d água no regulamento. Chegou-se a conclusão que há uma relação direta entre incentivo e desempenho. Os resultados aqui encontrados buscam facilitar o conhecimento e a tomada de decisão de pesquisadores, investidores, empresas gestoras, Corretoras e Distribuidoras, fundos de pensão e dos demais interessados na indústria de fundos de investimento em ações no Brasil.

Optimisation of stir bar sorptive extraction and liquid desorption combined with large volume injection-gas chromatography–quadrupole mass spectrometry for the determination of volatile compounds in wines

Stir bar sorptive extraction and liquid desorption followed by large volume injection coupled to gas chromatography–quadrupole mass spectrometry (SBSE–LD/LVI-GC–qMS) had been applied for the determination of volatiles in wines. The methodology was optimised in terms of extraction time and influence of ethanol in the matrix; LD conditions, and instrumental settings. The optimisation was carried out by using 10 standards representative of the main chemical families of wine, i.e. guaiazulene, E,E-farnesol, β-ionone, geranylacetone, ethyl decanoate, β-citronellol, 2-phenylethanol, linalool, hexyl acetate and hexanol. The methodology shows good linearity over the concentration range tested, with correlation coefficients higher than 0.9821, a good reproducibility was attained (8.9–17.8%), and low detection limits were achieved for nine volatile compounds (0.05–9.09 μg L−1), with the exception of 2-phenylethanol due to low recovery by SBSE. The analytical ability of the SBSE–LD/LVI-GC–qMS methodology was tested in real matrices, such as sparkling and table wines using analytical curves prepared by using the 10 standards where each one was applied to quantify the structurally related compounds. This methodology allowed, in a single run, the quantification of 67 wine volatiles at levels lower than their respective olfactory thresholds. The proposed methodology demonstrated to be easy to work-up, reliable, sensitive and with low sample requirement to monitor the volatile fraction of wine.

Artificial fertilization of oocytes and sperm activation in pacu: effects of the spermatozoa:oocyte ratio, water volume, and in natura semen preservation

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Osteopenia diabética e pós-menopausa: efeito metabólico do zinco na recuperação do volume ósseo trabecular

Diabetes mellitus has been associated with bone metabolism alterations, such as osteopenia and osteporosis. So, the search of new anabolic agents promote bone mass gain can be important to prevent osteoporosis. The aim of this study was evaluate zinc anabolic effect over bone in diabetic and post-menopausal osteopenic models. Diabetes was induced by STZ (45mg/Kg of body weight) administration and post-menopausal by bilateral ovariectomy. Adults female Wistar rats (n=65) were divided in 5 groups: control group (n=15), ovariectomized without (n=15) and with zinc supplementation (n=10) groups, diabetic and ovarioctomized without (n=15) and with zinc supplementation (n=10) groups. Studied periods had been untill 90 days. Diabetic condition was confirmed hiperglicemic state and alterations of state with polyuria, polyphagia, polydipsia and glucosuria. Histomorphometric analysis showed that zinc supplementation increased trabecular thickness and reduced trabecular distance significantly in diabetic groups with similar values to those showed in control group. Correlation analysis of histomorphometric parameters with serum glucose concentration showed that more time in hyperglycemia more bone damage, as well as, zinc supplementation contributed to prevent this damage. Elevated serum glucose caused hyperzincuria, phosphaturia and calciuria. Zinc supplementation promoted increased levels of calcium and phosphorous ions in 90th days diabetic group. No alteration was observed by ovariectomy in mineral (Ca, P and Zn) serum and urine concentrations. Total serum Alkaline Phosphatase activity increased in diabetic groups, supplemented or not, compared with control group. However, Tartarate-Resistant Acid Phosphatase, magnesium and serum zinc did not altered in studied groups. Serum albumin was reduced only in diabetic groups. Serum creatinine was unaltered. These results support the hypotesis that zinc can be used to prevent and treat diabetic and post-menopausal osteopenia