915 resultados para concentrate


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The general circulation pattern in the western boundary of the SW Atlantic is dominated by the opposite flows of Malvinas (-Falkland)and Brazil Current. In the Confluence region both currents separate from the continental slope and flow offshore creating an area of strong contracts and complex dynamics. The shelf-break fronts off Argentina mark the transition between shelf waters of mixed origin and nutrient rich Malvinas waters. Two areas deserve special attention due to the steep gradients introduced by the outflow of important sources of continental waters: the Rio de la Plata and the Magellan Strait to the north and south of the study area. Characteristics of the front is the high primary and secondary production, and the presence of important invertebrate and fish stocks that concentrate along the front to feed or spawn. The area comprises nearly 30 o/o (333 million U$S in 1995)of all Argentine catches of fish and squid. Resources in the area, beyond the EEZ limits, support international fisheries mainly of Russia, Poland and Spain. (Document contains 15 pages & figs)

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This study was designed to compare the quality of veal produced from ‘Tudanca x Charolais’ cross (n=6) and Limousin (n=6) breeds when allowed to feed freely on mountain pastures and suckle naturally from birth to 7 months of age. After 80 days of age calves also had access to concentrate (maximum of 3 Kg/day), while mothers did not. At slaughter, Limousin calves were heavier (P<0.01) and provided better carcass yield (P<0.05) and conformation (P<0.001) than Tudanca calves. Tudanca beef provided higher fat content (P<0.05) was less tough (P<0.05), and was scored as more tender and juicy (P<0.1) with higher acceptability than Limousin beef (P<0.1). In general, Tudanca had a better fatty acid profile than Limousin beef, especially in terms of the content of polyunsaturated (P<0.05), long-chain polyunsaturated fatty acids (P<0.05) and their n-6/n-3 ratios (P<0.1), as well as vaccenic acid (P<0.1) and the overall trans-18:1 isomer profile.

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[EN] The main focus of this paper is the cohesion of the theme. First of all, placing anaphoric cohesion within the theoretical framework developed by Bronckart (1985, 1996), we need to distinguish between cohesion, connection and coherence; and furthermore, within the field of cohesion we need to distinguish between verbal cohesion and cohesion as regards nouns. Similarly, the paper also defines discourse as the linguistic realisation of the text, and talks about different types of discourse and textual genres. Next, the paper focuses on the different approaches to cohesion. Since anaphoric cohesion is the cornerstone of the study, some limits of this concept are defined and its main indicators specified. Studies carried out from four different perspectives are taken into consideration: those that focus on understanding pronominal anaphora; those that seek to analyse the discursive side of language acquisition; those that look at anaphora and written texts; and those that concentrate on the didactic side of anaphora. From the model offered by Bronckart’s theory and the aforementioned studies, the following hypothesis is extracted: in Basque, language development is something which takes a long time, and textual genre plays an important role in defining and determining this development.

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In the current paper an analytical solution for diffusive wave equation with the concentrate-distributed lateral inflow is yielded. Finite-difference numerical method is also employed to validate this model. The backwater effects drawn from lateral inflow on the mainstream are examined finally.

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Global warming of the oceans is expected to alter the environmental conditions that determine the growth of a fishery resource. Most climate change studies are based on models and scenarios that focus on economic growth, or they concentrate on simulating the potential losses or cost to fisheries due to climate change. However, analysis that addresses model optimization problems to better understand of the complex dynamics of climate change and marine ecosystems is still lacking. In this paper a simple algorithm to compute transitional dynamics in order to quantify the effect of climate change on the European sardine fishery is presented. The model results indicate that global warming will not necessarily lead to a monotonic decrease in the expected biomass levels. Our results show that if the resource is exploited optimally then in the short run, increases in the surface temperature of the fishery ground are compatible with higher expected biomass and economic profit.

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Workshop Research Data Management – Activities and Challenges 14-15 November 2011, Bonn The Knowledge Exchange initiative organised a workshop to highlight current activities and challenges with respect to research data management in the Knowledge Exchange partner countries and beyond. The workshop brought together experts from data centres, libraries, computational centres, funding organisations, publishing services and other institutions in the field of research and higher education who are working to improve research data management and encourage effective reuse of research data. A considerable part of the programme was dedicated to sharing perspectives from these communities, leading to the development of a roadmap of practical actions for the Knowledge Exchange initiative, partner organisations and other stakeholders to progress over the next two years. On the first day, principal investigators and project managers from a great variety of recent projects shared their insights on objectives and methods for improving data management ranging from discipline-specific to more general approaches. A series of short presentations of selected projects was followed by an extensive poster session that functioned as a “trade fair” of current trends and activities in the field of research data management. Moreover, the poster session offered ample network opportunities for participants. The second day was dedicated to intensive group discussions looking at a number of data management challenges. First the most important findings from the "Surfboard for 'Riding the Wave'" report were presented. This included the state of the art on activities and challenges in the field of research data management. The subgroups will concentrate on the following key themes: funding, incentives, training and technical infrastructure. These discussions culminated in the identification of practical recommendations for future cooperation on practical as well as on strategic levels that should be taken forward by the KE partner organisations and beyond. These activities aim to improve the sustainability of services and infrastructures at both national and international levels.

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Climate change is an important environmental problem and one whose economic implications are many and varied. This paper starts with the presumption that mitigation of greenhouse gases is a necessary policy that has to be designed in a cost effective way. It is well known that market instruments are the best option for cost effectiveness. But the discussion regarding which of the various market instruments should be used, how they may interact and what combinations of policies should be implemented is still open and very lively. In this paper we propose a combination of instruments: the marketable emission permits already in place in Europe for major economic sectors and a CO(2) tax for economic sectors not included in the emissions permit scheme. The study uses an applied general equilibrium model for the Spanish economy to compute the results obtained with the new mix of instruments proposed. As the combination of the market for emission permits and the CO(2) tax admits different possibilities that depend on how the mitigation is distributed among the economic sectors, we concentrate on four possibilities: cost-effective, equalitarian, proportional to emissions, and proportional to output distributions. Other alternatives to the CO(2) tax are also analysed (tax on energy, on oil and on electricity). Our findings suggest that careful, well designed policies are needed as any deviation imposes significant additional costs that increase more than proportionally to the level of emissions reduction targeted by the EU.

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The reduction of discards will only be achieved, if more effective methods of catch selection will be developed and used. In principle, the unavoidable by catch of commercial fish should be used for human consumption, independent of the requirements for minimum length and existing catch quotas. The amount of such bycatch should be charged to the total catch quota and preferably be used for processing of fish portions with skin (carcasses with skin), because this kind of processing results in higher yields and nutrional advantages compared to fillet processing. Unfortunately, nowadays, in the German fishery and fish trade this traditional form of supply is only of minor importance because of the predominance of fillets and fillet products. However, cooperation between fishing industry and fish trade and a good advertising of processed fish portions with skin could overcome this problem. In the pelagic fishery of herring, mackerel and other similar pelagic species the bycatch of small sized specimen of these species can be a problem. These small sized fish can principally be processed to traditional fish products, but the processing costs for them are much higher. The prospects for processing of the bycatch into minced fish meat, fish protein concentrate or fish protein hydrolysate are very poor under the existing regime in the German fishing industry. A further way for processing of the bycatch, which can not be used for human consumption, is the production of fishmeal. However, only three German factory ships dispose of fish meal plants. Under the current economic conditions, i.e. because of limited storage capacity, the Ger-man trawler and cutter fleet is not able to transport the bycatch for fish meal production ashore.

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This thesis is mainly concerned with the application of groups of transformations to differential equations and in particular with the connection between the group structure of a given equation and the existence of exact solutions and conservation laws. In this respect the Lie-Bäcklund groups of tangent transformations, particular cases of which are the Lie tangent and the Lie point groups, are extensively used.

In Chapter I we first review the classical results of Lie, Bäcklund and Bianchi as well as the more recent ones due mainly to Ovsjannikov. We then concentrate on the Lie-Bäcklund groups (or more precisely on the corresponding Lie-Bäcklund operators), as introduced by Ibragimov and Anderson, and prove some lemmas about them which are useful for the following chapters. Finally we introduce the concept of a conditionally admissible operator (as opposed to an admissible one) and show how this can be used to generate exact solutions.

In Chapter II we establish the group nature of all separable solutions and conserved quantities in classical mechanics by analyzing the group structure of the Hamilton-Jacobi equation. It is shown that consideration of only Lie point groups is insufficient. For this purpose a special type of Lie-Bäcklund groups, those equivalent to Lie tangent groups, is used. It is also shown how these generalized groups induce Lie point groups on Hamilton's equations. The generalization of the above results to any first order equation, where the dependent variable does not appear explicitly, is obvious. In the second part of this chapter we investigate admissible operators (or equivalently constants of motion) of the Hamilton-Jacobi equation with polynornial dependence on the momenta. The form of the most general constant of motion linear, quadratic and cubic in the momenta is explicitly found. Emphasis is given to the quadratic case, where the particular case of a fixed (say zero) energy state is also considered; it is shown that in the latter case additional symmetries may appear. Finally, some potentials of physical interest admitting higher symmetries are considered. These include potentials due to two centers and limiting cases thereof. The most general two-center potential admitting a quadratic constant of motion is obtained, as well as the corresponding invariant. Also some new cubic invariants are found.

In Chapter III we first establish the group nature of all separable solutions of any linear, homogeneous equation. We then concentrate on the Schrodinger equation and look for an algorithm which generates a quantum invariant from a classical one. The problem of an isomorphism between functions in classical observables and quantum observables is studied concretely and constructively. For functions at most quadratic in the momenta an isomorphism is possible which agrees with Weyl' s transform and which takes invariants into invariants. It is not possible to extend the isomorphism indefinitely. The requirement that an invariant goes into an invariant may necessitate variants of Weyl' s transform. This is illustrated for the case of cubic invariants. Finally, the case of a specific value of energy is considered; in this case Weyl's transform does not yield an isomorphism even for the quadratic case. However, for this case a correspondence mapping a classical invariant to a quantum orie is explicitly found.

Chapters IV and V are concerned with the general group structure of evolution equations. In Chapter IV we establish a one to one correspondence between admissible Lie-Bäcklund operators of evolution equations (derivable from a variational principle) and conservation laws of these equations. This correspondence takes the form of a simple algorithm.

In Chapter V we first establish the group nature of all Bäcklund transformations (BT) by proving that any solution generated by a BT is invariant under the action of some conditionally admissible operator. We then use an algorithm based on invariance criteria to rederive many known BT and to derive some new ones. Finally, we propose a generalization of BT which, among other advantages, clarifies the connection between the wave-train solution and a BT in the sense that, a BT may be thought of as a variation of parameters of some. special case of the wave-train solution (usually the solitary wave one). Some open problems are indicated.

Most of the material of Chapters II and III is contained in [I], [II], [III] and [IV] and the first part of Chapter V in [V].

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This study includes an analysis of the trawl survey that was carried out by the Kainji Lake Fisheries Promotion Project in May, 1997. The objective of the survey was to assess the biomass and the potential yield of clupeids and the carrying capacity of the beach seine fishery in the entire Kainji Lake (Nigeria). The biomass of the beach seine by-catch was also estimated. The density (kg /km super(3)) of the clupeids was higher in the Bussa and Foge than in the other stations. The lowest density of clupeids was in the Anfani station followed by Jetty, both in the southern basin. These stations were the deepest parts of all the areas trawled, measuring between 37-120 m of depth. There was an inverse correlation between depth trawled and the catch rates of clupeids, though the correlation was poor. The average annual biomass of the clupeids was estimated at 36,769.85 Mt in the entire Lake with an MSY of 11,705.95 Mt. The smaller species, Sierrathrissa leonensis, made up about 97% of the total clupeid population in the lake and occurred at a shallower depth than the larger species Pellonula afzeliusi. From the clupeid production statistics in 1996, it is estimated that the MSY is already overshot by 34%. Therefore, about 698 beach seines instead of the present 810 would be sufficient for sustainable exploitation of the clupeid stocks. Because of the substantial by-catch in the beach seines, this fishing method was banned from Kainji Lake in 1997. An offshore open water seine net is recommended to replace the beach seines on the lake. The number of these nets should not exceed 500. The current ban on beach seine is supported by this study. Nevertheless, and since the ban may not be 100% effective, effort should concentrate on maintaining that the number of beach seines must be kept at most at the present level. Recommendation is made against the introduction of the pair trawling not only from an economic point of view but also for resource conservation, legal and social reasons. The development of this fishery could pose a serious danger to continuity of stocks. It is proposed that priority be given to the development of an open water seine which is at the same level of exploitation as the beach seine and requires similar cost to acquire. (PDF contains 39 pages)

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Research has proven that Shoreline Erosion is caused by excess water contained within the shore face. This Research presents an opportunity to control erosion by managing the near shore water table. Our Research on Bogue Banks North Carolina suggests that our buildings and other impervious surfaces collect and concentrate water from storm rain runoff into the surface water table and within the critical beach front water exit point. Presently our Potable Fresh Water is supplied from deep wells located beneath an impervious layer of Marl. After our use, the Waste water is drained into the Surface Aquifer, the combined waste and storm rain water raises the Surface Aquifer water table and produces Erosion. The Deep Aquifers presently supplying our Potable Water have an unknown recharge rate, with increasing reports of Salt Water intrusion. We believe our Vital Fresh water supply system should be modified to supply Reverse Osmosis treatment plants from shallow wells. This will lower the Surface Water Table. These Shallow wells, either horizontal or vertical, might be located within the beach front, adjacent to high erosion risk properties. Beach Drains and Reverse Osmosis Water systems are new and proven technologies. By combining these technologies we can reduce or reverse Shore Erosion, ensure a safe Potable Water supply, reduce requirements for periodic beach nourishment, reduce taxes and protect our property well into the Future. (PDF contains 5 pages)

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[EN] The purpose of this review article is to illustrate synthetic aspects of functionalized phosphorus derivatives containing an oximo moiety at the beta-position. First section will be focused on the synthesis of phosphine oxides, phosphonates or phosphonium salts containing an oxime group. The synthesis of these derivatives comprises the carbon–phosphorus single bond construction by reaction of haloximes with phosphorus derivatives, nucleophilic addition of phosphorus reagents to carbonyl compounds, or nucleophilic addition of phosphorus reagents to nitro olefins. This section will also concentrate on the most practical routes for the synthesis of the target compounds, through carbon–nitrogen double bond formation, which are as follows: condensation processes of carbonyl compounds and hydroxylamine derivatives or addition of hydroxylamines to allenes or alkynes. The preparative use of beta-oximo phosphorus derivatives as synthetic intermediates will be discussed in a second section, comprising olefination reaction, oxidation of oximes to nitrile oxides by reaction at the C-N double bond of the oxime moiety, oxidation of these substrates to nitrosoalkenes, reduction to the corresponding hydroxylamines and some reactions at the hydroxyl group of the hydroxyimino moiety.

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Spontaneous emission into the lasing mode fundamentally limits laser linewidths. Reducing cavity losses provides two benefits to linewidth: (1) fewer excited carriers are needed to reach threshold, resulting in less phase-corrupting spontaneous emission into the laser mode, and (2) more photons are stored in the laser cavity, such that each individual spontaneous emission event disturbs the phase of the field less. Strong optical absorption in III-V materials causes high losses, preventing currently-available semiconductor lasers from achieving ultra-narrow linewidths. This absorption is a natural consequence of the compromise between efficient electrical and efficient optical performance in a semiconductor laser. Some of the III-V layers must be heavily doped in order to funnel excited carriers into the active region, which has the side effect of making the material strongly absorbing.

This thesis presents a new technique, called modal engineering, to remove modal energy from the lossy region and store it in an adjacent low-loss material, thereby reducing overall optical absorption. A quantum mechanical analysis of modal engineering shows that modal gain and spontaneous emission rate into the laser mode are both proportional to the normalized intensity of that mode at the active region. If optical absorption near the active region dominates the total losses of the laser cavity, shifting modal energy from the lossy region to the low-loss region will reduce modal gain, total loss, and the spontaneous emission rate into the mode by the same factor, so that linewidth decreases while the threshold inversion remains constant. The total spontaneous emission rate into all other modes is unchanged.

Modal engineering is demonstrated using the Si/III-V platform, in which light is generated in the III-V material and stored in the low-loss silicon material. The silicon is patterned as a high-Q resonator to minimize all sources of loss. Fabricated lasers employing modal engineering to concentrate light in silicon demonstrate linewidths at least 5 times smaller than lasers without modal engineering at the same pump level above threshold, while maintaining the same thresholds.