JOURNAL OF FOOD QUALITY, Issue 3 2000
JORGE A. PINO
ABSTRACT Isolation of volatile constituents from fresh and processed grapefruit juice by a simple technique afforded up to 20 components in each juice type. Many of these constituents are known to contribute to grapefruit juice flavor. Multivariate analysis utilizing the concentration data of twelve constituents allowed classification of the juice samples according to processing conditions. The classification corresponded to expected flavor quality. [source]

Analysis of Headspace Volatile and Oxidized Volatile Compounds in DHA-enriched Fish Oil on Accelerated Oxidative Storage

JOURNAL OF FOOD SCIENCE, Issue 7 2003
H. Lee
ABSTRACT: Oxidative stability of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) and volatile and oxidized volatile compounds in 2 types of DHA-enriched fish oil, triacylglycerol (TG) and ethyl ester (EE), were studied during storage at 80 °C with aeration. The rate of DHA autoxidation was higher than that of EPA. DHA in EE form was more susceptible to autoxidation than in TG form. Thirty-one volatile compounds were identified in EE and 23 volatile compounds in TG. (E)-2-pentenal, 2-(1-pentenyl) furan, and (E,E)-2,4-heptadienal were commonly detected as oxidized volatile compounds from TG and EE fish oil. These volatile oxidized compounds might be formed mainly from the oxidation of DHA and EPA, the main fatty acids of the oil. [source]

Volatile and Nonvolatile Amines in Mediterranean Hake as Function of their Storage Temperature

JOURNAL OF FOOD SCIENCE, Issue 1 2001
S. Baixas-Nogueras
ABSTRACT: The main amines in frozen and fresh hake (Merluccius merluccius) are the natural polyamines, spermidine. The levels of volatile and nonvolatile amines during storage of hake were strogly dependent on temperature. In samples stored at -20° only changes in dimethylamine and agmatine were found, whereas major changes were observed in samples stored at higher temperatures. Cadaverine was the major amine formed followed by histamine, putrescine and tyramine. The maximum levels of biogenic amines were lower than those reported for other fish species. Trimethylamine and biogenic amines related to hake spollage showed levels higher in fresh than in frozen samples, whereas levels of natural polyamines were not statistically different. [source]

Have Individual Stocks Become More Volatile?

THE JOURNAL OF FINANCE, Issue 1 2001
An Empirical Exploration of Idiosyncratic Risk
This paper uses a disaggregated approach to study the volatility of common stocks at the market, industry, and firm levels. Over the period from 1962 to 1997 there has been a noticeable increase in firm-level volatility relative to market volatility. Accordingly, correlations among individual stocks and the explanatory power of the market model for a typical stock have declined, whereas the number of stocks needed to achieve a given level of diversification has increased. All the volatility measures move together countercyclically and help to predict GDP growth. Market volatility tends to lead the other volatility series. Factors that may be responsible for these findings are suggested. [source]

A Parsimonious Macroeconomic Model for Asset Pricing

ECONOMETRICA, Issue 6 2009
Fatih Guvenen
I study asset prices in a two-agent macroeconomic model with two key features: limited stock market participation and heterogeneity in the elasticity of intertemporal substitution in consumption (EIS). The model is consistent with some prominent features of asset prices, such as a high equity premium, relatively smooth interest rates, procyclical stock prices, and countercyclical variation in the equity premium, its volatility, and in the Sharpe ratio. In this model, the risk-free asset market plays a central role by allowing non-stockholders (with low EIS) to smooth the fluctuations in their labor income. This process concentrates non-stockholders' labor income risk among a small group of stockholders, who then demand a high premium for bearing the aggregate equity risk. Furthermore, this mechanism is consistent with the very small share of aggregate wealth held by non-stockholders in the U.S. data, which has proved problematic for previous models with limited participation. I show that this large wealth inequality is also important for the model's ability to generate a countercyclical equity premium. When it comes to business cycle performance, the model's progress has been more limited: consumption is still too volatile compared to the data, whereas investment is still too smooth. These are important areas for potential improvement in this framework. [source]

The Unemployment Volatility Puzzle: Is Wage Stickiness the Answer?

ECONOMETRICA, Issue 5 2009
Christopher A. Pissarides
I discuss the failure of the canonical search and matching model to match the cyclical volatility in the job finding rate. I show that job creation in the model is influenced by wages in new matches. I summarize microeconometric evidence and find that wages in new matches are volatile and consistent with the model's key predictions. Therefore, explanations of the unemployment volatility puzzle have to preserve the cyclical volatility of wages. I discuss a modification of the model, based on fixed matching costs, that can increase cyclical unemployment volatility and is consistent with wage flexibility in new matches. [source]

Currency boards: More than a quick fix?

ECONOMIC POLICY, Issue 31 2000
Atish R. Ghosh
Once a popular colonial monetary arrangement, currency boards fell into disuse as countries gained political independence. But recently, currency boards have made a remarkable come-back. This essay takes a critical look at their performance. Are currency boards really a panacea for achieving low inflation and high growth? Or do they merely provide a ,quick fix' allowing authorities to neglect fundamental reforms and thus fail to yield lasting benefits? We have three major findings. First, the historical track record of currency boards is sterling, with few instances of speculative attacks and virtually no ,involuntary' exits. Countries that did exit from currency boards did so mainly for political, rather than economic reasons, and such exits were usually uneventful. Second, modern currency boards have often been instituted to gain credibility following a period of high or hyperinflation, and in this regard, have been remarkably successful. Countries with currency boards experienced lower inflation and higher (if more volatile) GDP growth compared to both floating regimes and simple pegs. The inflation difference reflects both a lower growth rate of money supply (a ,discipline effect'), and a faster growth of money demand (a ,credibility effect'). The GDP growth effect is significant, but may simply reflect a rebound from depressed levels. Third, case studies reveal the successful introduction of a currency board to be far from trivial, requiring lengthy legal and institutional changes, as well as a broad economic and social consensus for the implied commitment. Moreover, there are thorny issues, as yet untested, regarding possible exits from a currency board. Thus currency boards do not provide easy solutions. But if introduced in the right circumstances, with some built-in flexibility, they can be an important tool for gaining credibility and achieving macroeconomic stabilization. [source]

High-efficiency peptide analysis on monolithic multimode capillary columns: Pressure-assisted capillary electrochromatography/capillary electrophoresis coupled to UV and electrospray ionization-mass spectrometry

ELECTROPHORESIS, Issue 21 2003
Alexander R. Ivanov
Abstract High-efficiency peptide analysis using multimode pressure-assisted capillary electrochromatography/capillary electrophoresis (pCEC/pCE) monolithic polymeric columns and the separation of model peptide mixtures and protein digests by isocratic and gradient elution under an applied electric field with UV and electrospray ionization-mass spectrometry (ESI-MS) detection is demonstrated. Capillary multipurpose columns were prepared in silanized fused-silica capillaries of 50, 75, and 100 ,m inner diameters by thermally induced in situ copolymerization of methacrylic monomers in the presence of n -propanol and formamide as porogens and azobisisobutyronitrile as initiator. N -Ethylbutylamine was used to modify the chromatographic surface of the monolith from neutral to cationic. Monolithic columns were termed as multipurpose or multimode columns because they showed mixed modes of separation mechanisms under different conditions. Anion-exchange separation ability in the liquid chromatography (LC) mode can be determined by the cationic chromatographic surface of the monolith. At acidic pH and high voltage across the column, the monolithic stationary phase provided conditions for predominantly capillary electrophoretic migration of peptides. At basic pH and electric field across the column, enhanced chromatographic retention of peptides on monolithic capillary column made CEC mechanisms of migration responsible for separation. The role of pressure, ionic strength, pH, and organic content of the mobile phase on chromatographic performance was investigated. High efficiencies (exceeding 300,000 plates/m) of the monolithic columns for peptide separations are shown using volatile and nonvolatile, acidic and basic buffers. Good reproducibility and robustness of isocratic and gradient elution pressure-assisted CEC/CE separations were achieved for both UV and ESI-MS detection. Manipulation of the electric field and gradient conditions allowed high-throughput analysis of complex peptide mixtures. A simple design of sheathless electrospray emitter provided effective and robust low dead volume interfacing of monolithic multimode columns with ESI-MS. Gradient elution pressure-assisted mixed-mode separation CE/CEC-ESI-MS mass fingerprinting and data-dependent pCE/pCEC-ESI-MS/MS analysis of a bovine serum albumin (BSA) tryptic digest in less than 5 min yielding high sequence coverage (73%) demonstrated the potential of the method. [source]

Characterization of marine isoprene-degrading communities

ENVIRONMENTAL MICROBIOLOGY, Issue 12 2009
Laura Acuña Alvarez
Summary Isoprene is a volatile and climate-altering hydrocarbon with an atmospheric concentration similar to that of methane. It is well established that marine algae produce isoprene; however, until now there was no specific information about marine isoprene sinks. Here we demonstrate isoprene consumption in samples from temperate and tropical marine and coastal environments, and furthermore show that the most rapid degradation of isoprene coincides with the highest rates of isoprene production in estuarine sediments. Isoprene-degrading enrichment cultures, analysed by denaturing gradient gel electrophoresis and 454 pyrosequencing of the 16S rRNA gene and by culturing, were generally dominated by Actinobacteria, but included other groups such as Alphaproteobacteria and Bacteroidetes, previously not known to degrade isoprene. In contrast to specialist methane-oxidizing bacteria, cultivated isoprene degraders were nutritionally versatile, and nearly all of them were able to use n -alkanes as a source of carbon and energy. We therefore tested and showed that the ubiquitous marine hydrocarbon-degrader, Alcanivorax borkumensis, could also degrade isoprene. A mixture of the isolates consumed isoprene emitted from algal cultures, confirming that isoprene can be metabolized at low, environmentally relevant concentrations, and suggesting that, in the absence of spilled petroleum hydrocarbons, algal production of isoprene could maintain viable populations of hydrocarbon-degrading microbes. This discovery of a missing marine sink for isoprene is the first step in obtaining more robust predictions of its flux, and suggests that algal-derived isoprene provides an additional source of carbon for diverse microbes in the oceans. [source]

Micro-reactor for transesterification of plant seed oils

EUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 5 2009
Phattaraporn Kaewkool
Abstract The fatty acid compositions of vegetable or other plant seed oils are generally determined by gas chromatography (GC). Methyl esters (the most volatile derivatives) are the preferred derivatives for GC analysis. Esters of higher alcohols are good for the separation of volatile and positional isomers. All the esters of the C1,C8 alcohols of vegetable oils were silmilarly prepared by passing the reaction mixture containing the desired alcohol, oil and tetrahydrofuran through the micro-reactor (a 3-mL dispossible syringe packed with 0.5,g of NaOH powder). The reaction products were acidified with acetic acid and the mixture was analyzed by high-performance size exclusion chromatography and GC. Transesterification was quantitative for primary alcohols, but an appreciable amount of free fatty acids was formed for secondary alcohols. Coriander seed oil was quantitatively esterified with 2-ethyl 1-hexanol with the micro-reactor in less than 1,min. Oleic and petroselinic acid 2-ethyl 1-hexyl esters are baseline separated on an Rtx-2330 capillary column (30,m×0.25,mm, 0.25,µm film thickness). [source]

A direct main olfactory bulb projection to the ,vomeronasal' amygdala in female mice selectively responds to volatile pheromones from males

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 3 2009
Ningdong Kang
Abstract The main olfactory system, like the accessory olfactory system, responds to pheromones involved in social communication. Whereas pheromones detected by the accessory system are transmitted to the hypothalamus via the medial (,vomeronasal') amygdala, the pathway by which pheromones are detected and transmitted by the main system is not well understood. We examined in female mice whether a direct projection from mitral/tufted (M/T) cells in the main olfactory bulb (MOB) to the medial amygdala exists, and whether medial amygdala-projecting M/T cells are activated by volatile urinary odors from conspecifics or a predator (cat). Simultaneous anterograde tracing using Phaseolus vulgaris leucoagglutinin and Fluoro-Ruby placed in the MOB and accessory olfactory bulb (AOB), respectively, revealed that axons of MOB M/T cells projected to superficial laminae of layer Ia in anterior and posterodorsal subdivisions of the medial amygdala, whereas projection neurons from the AOB sent axons to non-overlapping, deeper layer Ia laminae of the same subdivisions. Placement of the retrograde tracer cholera toxin B into the medial amygdala labeled M/T cells that were concentrated in the ventral MOB. Urinary volatiles from male mice, but not from female conspecifics or cat, induced Fos in medial amygdala-projecting MOB M/T cells of female subjects, suggesting that information about male odors is transmitted directly from the MOB to the ,vomeronasal' amygdala. The presence of a direct MOB-to-medial amygdala pathway in mice and other mammals could enable volatile, opposite-sex pheromones to gain privileged access to diencephalic structures that control mate recognition and reproduction. [source]

The vomeronasal organ is required for the expression of lordosis behaviour, but not sex discrimination in female mice

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 2 2006
Matthieu Keller
Abstract The role of the vomeronasal organ (VNO) in mediating neuroendocrine responses in female mice is well known; however, whether the VNO is equally important for sex discrimination is more controversial as evidence exists for a role of the main olfactory system in mate recognition. Therefore, we studied the effect of VNO removal (VNOx) on the ability of female mice to discriminate between volatile and non-volatile odours of conspecifics of the two sexes and in different endocrine states using Y-maze tests. VNOx female mice were able to reliably distinguish between male and female or male and gonadectomized (gdx) male volatile odours. However, when subjects had to discriminate between male and female or gdx male non-volatile odours, VNOx females were no longer able to discriminate between sex or different endocrine status. These results thus show that the VNO is primarily involved in the detection and processing of non-volatile odours, and that female mice can use volatile odours detected and processed by the main olfactory system for mate recognition. However, VNO inputs are needed to promote contact with the male, including facilitation of lordosis responses to his mounts. A single subcutaneous injection with gonadotropin-releasing hormone (GnRH) partially reversed the deficit in lordosis behaviour observed in VNOx females suggesting that VNO inputs may reach hypothalamic GnRH neurons to influence the display of sexual behaviour. [source]

Modelling volatility clustering in electricity price return series for forecasting value at risk

EUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 1 2009
R. G. Karandikar
Abstract Modelling of non-stationary time series using regression methodology is challenging. The wavelet transforms can be used to model non-stationary time series having volatility clustering. The traditional risk measure is variance and now a days Value at Risk (VaR) is widely used in finance. In competitive environment, the prices are volatile and price risk forecasting is necessary for the market participants. The forecasting period may be 1 week or higher depending upon the requirement. In this paper, a model is developed for volatility clustering in electricity price return series and its application for forecasting VaR is demonstrated. The first model is using GARCH (1, 1). The VaR of variance rate series, that is worst-case volatility is calculated using variance method using wavelet transform. The model is used to forecast variance rate (volatility) for a sample case of 1-week half-hourly price return series. The second model developed is for forecasting VaR for price return series of 440 days. This model is developed using wavelets via multi-resolution analysis and uses regime-switching technique. The historical data of daily average prices is obtained from 100% pool type New South Wales (NSW), a zonal market of National Electricity Market (NEM), Australia. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Influence of carbonation on aroma release from liquid systems using an artificial throat and a proton transfer reaction,mass spectrometric technique (PTR,MS)

FLAVOUR AND FRAGRANCE JOURNAL, Issue 5 2009
Maria Ángeles Pozo-Bayón
Abstract To determine whether carbonation affects aroma release from liquid systems, carbonated and non-carbonated flavoured model systems were prepared and volatile release was determined under static (equilibrium) and dynamic conditions. A model flavour system was added as a single compound or as a mixture of the six aroma compounds used in this study. Volatile release under dynamic conditions involved using a home-made device simulating an artificial throat, coupled to a proton transfer mass spectrometer (PTR,MS). The results showed that carbonation increased the release of most of the aroma compounds in both static and in dynamic testing conditions. The extent of this effect depended, however, on the physicochemical characteristics of the aroma compounds (the most volatile and most hydrophobic compounds were affected more). Release was also increased if the aroma compounds were added as a mixture rather than as individual compounds. CO2 appears to be a key factor responsible for the enhanced release of flavourings from carbonated liquid systems. Copyright © 2009 John Wiley & Sons, Ltd. [source]

A selective and sensitive approach to characterize odour-active and volatile constituents in small-scale human milk samples

FLAVOUR AND FRAGRANCE JOURNAL, Issue 6 2007
Andrea Buettner
Abstract A sensitive and selective analytical approach was developed for the characterization of trace volatile and odorous substances in body fluids. The methodology was successfully applied for identification of more than 40 characteristic odorants in human milk. The technique comprises a modified stir bar sorptive extraction system in combination with two-dimensional gas chromatographic separation and parallel mass spectrometric and olfactometric characterization of the analytes. The present study shows that the technique can be used for both direct extractive sampling and headspace analysis, and that it is applicable for small sample volumes. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Coffee ,avour: an overview

FLAVOUR AND FRAGRANCE JOURNAL, Issue 2 2004
Roberto A. Buffo
Abstract This paper is a concise review of the research on coffee ,avour to serve as a rapid reference on the subject. It covers the process of roasting coffee beans, the volatile and non-volatile components generated by the process and the chemical reactions responsible for their formation. Volatile compounds signi,cant on the determination of coffee aroma are given according to the most recent research. Finally, the paper discusses the chemical indexes used over the years to characterize coffee ,avour deterioration and estimation of shelf-life. Copyright © 2004 John Wiley & Sons, Ltd. [source]

Soil organic carbon contents in long-term experimental grassland plots in the UK (Palace Leas and Park Grass) have not changed consistently in recent decades

GLOBAL CHANGE BIOLOGY, Issue 7 2009
D. W. HOPKINS
Abstract A recent report of widespread declines in soil organic C (SOC) in the UK over the 10,25 years until the early 2000s has focussed attention on the importance of resampling previously characterized sites to assess long-term trends in SOC contents and the importance of soils as a potentially volatile and globally significant reservoir of terrestrial C. We have used two sets of long-term experimental plots which have been under constant and known management for over a century and for which historical data exist that allow comparison over recent decades to determine what, if any, changes in SOC content have occurred. The plots used are the Palace Leas (PL) Meadow Hay Plots in north-east England (UK) established in 1897, and from the Park Grass (PG) Continuous Hay experiment established in 1856 at Rothamsted in south-east England. Collectively, these plots represent the only grassland sites in the UK under long-term management where changes in SOC over several decades can be assessed, and are probably unique in the world. The plots have received different manure and fertilizer treatment and have been under known management for at least 100 years. In 1982, total SOC contents were determined for the 0,27 cm layer of six of the PL plots using measurements of SOC concentrations, bulk density and soil depth. In 2006, the same six PL plots were resampled and SOC contents determined again. Four of the plots showed no net change in SOC content, but two plots showed net loss of SOC of 15% and 17% (amounting to decreases of 18 and 15 t C ha,1) since 1982. However, these differences in total SOC content were in a similar range to the variations in bulk density (6,31%) with changing soil water content. In 1959, the soil masses and SOC concentrations to 23 cm depth were measured on six PG plots with fertilizer and manure treatments corresponding closely with those measured on PL. In 2002, the SOC concentrations on the same plots were measured again. On three of the PG plots, SOC concentrations had declined by 2,10%, but in the other three it had increased by 4,8% between 1959 and 2002. If it is assumed that the soil bulk density had not changed over this period, the losses of SOC from the top soils ranged range from 10 to 3 t C ha,1, while the gains ranged from 4 to 7 t C ha,1. When the differences with time in SOC contents for the six PL and the six PG plots were examined using paired t -tests, that is, regarding the plots as two sets of six replicate permanent grasslands, there were no significant differences between 1982 and 2006 for the PL plots or between 1959 and 2002 for the PG plots. Thus, these independent observations on similar plots at PL and PG indicate there has been no consistent decrease in SOC stocks in surface soils under old, permanent grassland in England in recent decades, even though meteorological records for both sites indicate significant warming of the soil and air between 1980 and 2000. Because the potential influences of changes in management or land use have been definitively excluded, and measured rather than derived bulk densities have been used to convert from SOC concentrations to SOC amounts, our observations question whether for permanent grassland in England, losses in SOC in recent decades reported elsewhere can be attributed to widespread environmental change. [source]

Smoothing Mechanisms in Defined Benefit Pension Accounting Standards: A Simulation Study,

ACCOUNTING PERSPECTIVES, Issue 2 2009
Cameron Morrill
ABSTRACT The accounting for defined benefit (DB) pension plans is complex and varies significantly across jurisdictions despite recent international convergence efforts. Pension costs are significant, and many worry that unfavorable accounting treatment could lead companies to terminate DB plans, a result that would have important social implications. A key difference in accounting standards relates to whether and how the effects of fluctuations in market and demographic variables on reported pension cost are "smoothed". Critics argue that smoothing mechanisms lead to incomprehensible accounting information and induce managers to make dysfunctional decisions. Furthermore, the effectiveness of these mechanisms may vary. We use simulated data to test the volatility, representational faithfulness, and predictive ability of pension accounting numbers under Canadian, British, and international standards (IFRS). We find that smoothed pension expense is less volatile, more predictive of future expense, and more closely associated with contemporaneous funding than is "unsmoothed" pension expense. The corridor method and market-related value approaches allowed under Canadian GAAP have virtually no smoothing effect incremental to the amortization of actuarial gains and losses. The pension accrual or deferred asset is highly correlated with the pension plan deficit/surplus. Our findings complement existing, primarily archival, pension accounting research and could provide guidance to standard-setters. [source]

Decision making using time-dependent knowledge: knowledge augmentation using qualitative reasoning

INTELLIGENT SYSTEMS IN ACCOUNTING, FINANCE & MANAGEMENT, Issue 1 2001
Song Jin Yu
In this paper we propose a method to enhance the performance of knowledge-based decision-support systems, knowledge of which is volatile and incomplete by nature in a dynamically changing situation, by providing meta-knowledge augmented by the Qualitative Reasoning (QR) approach. The proposed system intends to overcome the potential problem of completeness of the knowledge base. Using the deep meta-knowledge incorporated into the QR module, along with the knowledge we gain from applying inductive learning, we then identify the ongoing process and amplify the effects of each pending process to the attribute values. In doing so, we apply the QR models to enhance or reveal the patterns which are otherwise less obvious. The enhanced patterns can eventually be used to improve the classification of the data samples. The success factor hinges on the completeness of the QR process knowledge base. With enough processes taking place, the influences of each process will lead prediction in a direction that can reflect more of the current trend. The preliminary results are successful and shed light on the smooth introduction of Qualitative Reasoning to the business domain from the physical laboratory application. © 2001 John Wiley & Sons, Ltd. [source]

HOUSING AND THE BUSINESS CYCLE*

INTERNATIONAL ECONOMIC REVIEW, Issue 3 2005
Morris A. Davis
In the United States, the percentage standard deviation of residential investment is more than twice that of nonresidential investment. In addition, GDP, consumption, and both types of investment co-move positively. We reproduce these facts in a calibrated multisector growth model where construction, manufacturing, and services are combined, in different proportions, to produce consumption, business investment, and residential structures. New housing requires land in addition to new structures. The model can also account for important features of industry-level data. In particular, hours and output in all industries are positively correlated, and are most volatile in construction. [source]

Time-consistent optimal fiscal policy*

INTERNATIONAL ECONOMIC REVIEW, Issue 4 2003
Paul Klein
This article studies the properties of optimal fiscal policy in a stochastic growth model when the government cannot commit itself beyond the next period's capital income tax rate. We find that the results contrast markedly with those under full commitment. First, capital income tax rates are very high (65% on average versus close to zero on average under full commitment). Second, labor income taxes are rather low on average (about 12% versus a value of around 31% under full commitment). Finally, labor income taxes are quite volatile, whereas under full commitment their standard deviation is essentially zero. [source]

From Malthus to Modern Growth: Can Epidemics Explain the Three Regimes?*

INTERNATIONAL ECONOMIC REVIEW, Issue 2 2003
Nils-Petter Lagerlöf
We model demographic and economic long-run development in a setting where mortality is endogenous and subject to epidemic shocks. The model replicates the full transition from Malthusian stagnation to modern growth. Consistent with the historical facts, the economy also passes an intermediate post-Malthusian phase where growth rates of both population and per capita income increase simultaneously, as mortality rates fall and become less volatile. The escape from the Malthusian trap is the result of a series of mild epidemic shocks, making it inevitable at some stage, but its timing random. Calibrations show that it can differ by thousands of generations, absent differences in exogenous parameters. [source]

Kim Jong-Il of North Korea: in the shadow of his father,

INTERNATIONAL JOURNAL OF APPLIED PSYCHOANALYTIC STUDIES, Issue 3 2008
Jerrold M. Post
Abstract This paper explores the political personality of North Korea's leader, Kim Jong-Il, particularly in the context of his succession from his father, the founding leader Kim Il-Sung. Drawing upon what is known of Kim Jong-Il's childhood and family life, the paper examines the key personality formations that have shaped his political persona and leadership style, particularly his narcissism, paranoia and lack of empathy. Eccentric, reclusive and self-indulgent, Kim is depicted as an emotionally volatile, narcissistic personality who indulges in hedonistic behavior while ignoring the privations of his people. Copyright © 2004 Cornell University Press. [source]

Anaesthesia for endoscopic sinus surgery

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 7 2010
A. R. BAKER
Endoscopic sinus surgery is commonly performed and has a low risk of major complications. Intraoperative bleeding impairs surgical conditions and increases the risk of complications. Remifentanil appears to produce better surgical conditions than other opioid analgesics, and total intravenous anaesthesia with propofol may provide superior conditions to a volatile-based technique. Moderate hypotension with intraoperative , blockade is associated with better operating conditions than when vasodilating agents are used. Tight control of CO2 does not affect the surgical view. The use of a laryngeal mask may be associated with improved surgical conditions and a smoother emergence. It provides airway protection equivalent to that provided by an endotracheal tube in well-selected patients, but offers less protection from gastric regurgitation. Post-operatively, multimodal oral analgesia provides good pain relief, while long-acting local anaesthetics have been shown not to improve analgesia. [source]

SPME/GC/MS and sensory flavour profile analysis for estimation of authenticity of thyme honey

INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 2 2007
Demet Manna
Summary Volatiles of six commercially obtained thyme honey samples and a pure thyme honey sample were extracted and analysed by Solid phase micro extraction (SPME)/Gas chromatography (GC)/Mass spectrometry (MS) procedure. Excess amount of volatiles such as thymol (trace) and carvacrole (0.66%) that originate from thyme plants indicated adulteration by thyme essential oil in one of the commercial samples. Sensory flavour profile analysis showed that the flavour of pure thyme honey sample consisted of: sweet, honey, lilac, bitter almond, thyme, violet, waxy, sour, ginger, caramel and rose characters. Adulterated honey was detected to be the sweetest sample involving intense thyme flavour without honey character. 3,4,5-Trimethoxybenzaldehyde which is a volatile not found in other unifloral honeys, seems to be a possible marker, but further studies with certified thyme honey samples are necessary in order to confirm the utility of this compound in estimation of authenticity. [source]

Flavour encapsulation and controlled release , a review

INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 1 2006
Atmane Madene
Summary Flavours can be among the most valuable ingredients in any food formula. Even small amounts of some aroma substance can be expensive, and because they are usually delicate and volatile, preserving them is often a top concern of food manufacturers. Encapsulation describes different processes to cover an active compound with a protective wall material and it can be employed to treat flavours so as to impart some degree of protection against evaporation, reaction, or migration in a food. Encapsulation of flavours has been attempted and commercialized using many different methods such as spray drying, spray chilling or spray cooling, extrusion, freeze drying, coacervation and molecular inclusion. The choice of appropriate microencapsulation technique depends upon the end use of the product and the processing conditions involved in the manufacturing product. This overview describes each method cited above in terms of the basic chemical and/or physical principles involved and covers mechanisms of flavour release from food matrices. [source]

Financial Market Crises and Natural Resource Production

INTERNATIONAL REVIEW OF FINANCE, Issue 1 2010
JAMES R. BROWN
ABSTRACT During a financial crisis, the loss of access to world capital markets may force heavily indebted countries to accelerate their production of exhaustible resources. Few studies consider the impact that financial crises have on real behavior, and no existing studies appear to consider the impact a crisis might have on resource production. We find that four major state-owned enterprises in Brazil, Chile and Mexico substantially expanded their production and world market share of copper, iron ore and oil during the 1980s' international financial crisis. There was also a very large expansion, followed by a sharp contraction, of production of tin in Brazil and silver in Mexico. In contrast, Indonesia , a major resource producer who did not succumb to the 1980s' financial crisis , did not accelerate production during the 1980s' crisis, and resource production in the United States sharply contracted during this period. Our study provides new insights into why the prices of natural resources are so volatile and highlights a previously unexplored reason for financial contagion: one country's efforts to service its debt can drive down resource prices and revenues to other indebted resource producers. [source]

Herbivore-induced plant volatiles as cues for habitat assessment by a foraging parasitoid

JOURNAL OF ANIMAL ECOLOGY, Issue 1 2007
CEDRIC TENTELIER
Summary 1Animals usually require information about the current state of their habitat to optimize their behaviour. For this, they can use a learning process through which their estimate is continually updated according to the cues they perceive. Identifying these cues is a long-standing but still inveterate challenge for ecologists. 2The use of plant cues by aphid parasitoids for the assessment of habitat profitability and the adaptation of patch exploitation was studied. Grounding on predictions from optimal foraging theory, we tested whether parasitoids exploited host patches less intensively after visiting heavily infested plants than after visiting plants bearing fewer aphids. 3As predicted, after visiting heavily infested plants parasitoids reduced their residence time and attacked fewer hosts in the next patch. This was the case regardless of whether the aphids were actually present on the first plant, indicating that the cue came from the plant. Moreover, the level of infestation of a plant at some distance from the first plant visited affected parasitoid patch exploitation on the second plant in a similar manner, indicating that the cue was volatile. 4These results highlight a novel role of herbivore-induced volatiles in parasitoid foraging behaviour, different from the widely studied attraction at a distance. [source]

Pine shoot beetle, Tomicus piniperda (Col., Scolytidae), responses to common green leaf volatiles

JOURNAL OF APPLIED ENTOMOLOGY, Issue 2 2000
T. M. Poland
We tested the hypothesis that green leaf volatiles (GLVs) disrupt the response of overwintered pine shoot beetles, Tomicus piniperda (L.) to multiple-funnel traps baited with the attractive host volatile ,-pinene. A combination of four GLV alcohols, 1-hexanol (E)-2-hexen-1-ol (Z)-2-hexen-1-ol, and (Z)-3-hexen-1-ol, caused 54 and 36% reduction in the number of pine shoot beetles captured in two separate trapping experiments. Similarly, a combination of the four alcohols plus two GLV aldehydes, hexanal and (E)-2-hexenal, caused 38% reduction in the number of pine shoot beetles captured compared with ,-pinene alone. A blend of the two GLV aldehydes was not disruptive. None of the four GLV alcohols nor the two GLV aldehydes were disruptive when tested individually. The finding that the blend of four GLV alcohols reduced attraction of T. piniperda supports the general hypothesis that GLVs common to nonhost angiosperms are disruptive to conifer-attacking bark beetles (Scolytidae). [source]

The appropriation and repurposing of social technologies in higher education

JOURNAL OF COMPUTER ASSISTED LEARNING, Issue 1 2009
A. Hemmi
Abstract This paper presents some of the findings from a recent project that conducted a virtual ethnographic study of three formal courses in higher education that use ,Web 2.0' or social technologies for learning and teaching. It describes the pedagogies adopted within these courses, and goes on to explore some key themes emerging from the research and relating to the pedagogical use of weblogs and wikis in particular. These themes relate primarily to the academy's tendency to constrain and contain the possibly more radical effects of these new spaces. Despite this, the findings present a range of student and tutor perspectives which show that these technologies have significant potential as new collaborative, volatile and challenging environments for formal learning. [source]