191 research outputs found
Proposal of an FTIR Methodology to Monitor Oxidation Level in Used Engine Oils: Effects of Thermal Degradation and Fuel Dilution
This article describes a procedure, based on ASTM standards D7214 and E2412, that has been defined to improve quantification of oil oxidation in used engine oils. Taking into account typical problems that can be found in this type of sample, including thermal oxidation and fuel dilution, Fourier transform infrared (FTIR) spectra were analyzed also considering the effect of the oil formulation. Two zones were considered inside the typical wave number range for quantification of oxidation, where those problems can be detected and assessed more easily: zone A between 1725 and 1650 cm-1, where the main oxidation products, such as aldehydes, carboxylic acids, and ketones, occur due to thermal degradation of the oil; and zone B between 1770 and 1725 cm-1, where esters due to potential biodiesel dilution problems are detected. Copyright © Society of Tribologists and Lubrication Engineers.The authors are grateful for Spanish Grant TRA2008-06508 (GLAUTO) from the Ministerio de Ciencia e Innovacion-Direccion General de Investigacion for supporting this work.Macian Martinez, V.; Tormos, B.; Gomez Estrada, YA.; Salavert Fernández, JM. (2012). Proposal of an FTIR Methodology to Monitor Oxidation Level in Used Engine Oils: Effects of Thermal Degradation and Fuel Dilution. Tribology Transactions. 55(6):872-882. https://doi.org/10.1080/10402004.2012.721921S87288255
Confusion and dependence in uses of history
Many people argue that history makes a special difference to the subjects of biology and psychology, and that history does not make this special difference to other parts of the world. This paper will show that historical properties make no more or less of a difference to biology or psychology than to chemistry, physics, or other sciences. Although historical properties indeed make a certain kind of difference to biology and psychology, this paper will show that historical properties make the same kind of difference to geology, sociology, astronomy, and other sciences. Similarly, many people argue that nonhistorical properties make a special difference to the nonbiological and the nonpsychological world. This paper will show that nonhistorical properties make the same difference to all things in the world when it comes to their causal behavior and that historical properties make the same difference to all things in the world when it comes to their distributions. Although history is special, it is special in the same way to all parts of the worl
Clusters of ant colonies and robust criticality in a tropical agroecosystem
Although sometimes difficult to measure at large scales, spatial pattern is important in natural biological spaces as a determinant of key ecological properties such as species diversity, stability, resiliency and others(1-6). Here we demonstrate, at a large spatial scale, that a common species of tropical arboreal ant forms clusters of nests through a combination of local satellite colony formation and density- dependent control by natural enemies, mainly a parasitic fly. Cluster sizes fall off as a power law consistent with a so-called robust critical state(7). This endogenous cluster formation at a critical state is a unique example of an insect population forming a non- random pattern at a large spatial scale. Furthermore, because the species is a keystone of a larger network that contributes to the ecosystem function of pest control, this is an example of how spatial dynamics at a large scale can affect ecosystem service at a local level.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62598/1/nature06477.pd
Evaluation of genotypic and phenotypic methods for differentiation of the members of the Anginosus group streptococci
The terminology and classification of the Anginosus group streptococci has been inconsistent. We tested the utility of 16S rRNA gene and tuf gene sequencing and conventional biochemical tests for the reliable differentiation of the Anginosus group streptococci. Biochemical testing included Rapid ID 32 Strep, API Strep, Fluo-Card Milleri, Wee-tabs, and Lancefield antigen typing. Altogether, 61 Anginosus group isolates from skin and soft tissue infections and four reference strains were included. Our results showed a good agreement between 16S rRNA gene and tuf gene sequencing. Using the full sequence was less discriminatory than using the first part of the 16S rRNA gene. The three species could not be separated with the API 20 Strep test. Streptococcus intermedius could be differentiated from the other two species by β-galactosidase (ONPG) and β-N-acetyl-glucosaminidase reactions. Rapid ID 32 Strep β-glucosidase reaction was useful in separating S. anginosus strains from S. constellatus. In conclusion, both 16S rRNA gene and tuf gene sequencing can be used for the reliable identification of the Anginosus group streptococci. S. intermedius can be readily differentiated from the other two species by phenotypic tests; however, 16S rRNA gene or tuf gene sequencing may be needed for separating some strains of S. constellatus from S. anginosus
Current trends in the cardiovascular clinical trial arena (I)
The existence of effective therapies for most cardiovascular disease states, coupled with increased requirements that potential benefits of new drugs be evaluated on clinical rather than surrogate endpoints, makes it increasingly difficult to substantiate any incremental improvements in efficacy that these new drugs might offer. Compounding the problem is the highly controversial issue of comparing new agents with placebos rather than active pharmaceuticals in drug efficacy trials. Despite the recent consensus that placebos may be used ethically in well-defined, justifiable circumstances, the problem persists, in part because of increased scrutiny by ethics committees but also because of considerable lingering disagreement regarding the propriety and scientific value of placebo-controlled trials (and trials of antihypertensive drugs in particular). The disagreement also substantially affects the most viable alternative to placebo-controlled trials: actively controlled equivalence/noninferiority trials. To a great extent, this situation was prompted by numerous previous trials of this type that were marked by fundamental methodological flaws and consequent false claims, inconsistencies, and potential harm to patients. As the development and use of generic drugs continue to escalate, along with concurrent pressure to control medical costs by substituting less-expensive therapies for established ones, any claim that a new drug, intervention, or therapy is "equivalent" to another should not be accepted without close scrutiny. Adherence to proper methods in conducting studies of equivalence will help investigators to avoid false claims and inconsistencies. These matters will be addressed in the third article of this three-part series
Social rank in schools of juvenile yellowtail, Seriola quinqueradiata
The composition, stability and biotic factors of social rank in juvenile marine fish schools are demonstrated using juvenile yellowtails, Seriola quinequeradiata (Temminck et Schlegel: Carangidae). According to the frequency of aggressive behaviour, members within a school were divided into three categories: dominants (10-20%) intermediates (10-20%) and sub-ordinates (60-80%). Social rank was reset with the same hierarchy composition when dominants and intermediates were combined. Observation of individual aggressive behaviour using a video image analysis system revealed that starvation and an increase in fish densities accelerated aggression only in the dominants. In order to determine the durability of social rank, otoliths of dominant fish in eight experimental groups were labelled and the fish returned to their groups; six dominants appeared after one day and three after one week of rearing, indicating that social rank was maintained for at least one week (binomial distribution; P < 0.05). Total lengths of dominants were larger than tose of subordinates after one day of rearing, whereas dominants were smaller after one week. Social rank of this species is decided upon by individual aggressive tendency, but is not beneficial for feeding or growth
The link between volcanism and plutonism in epizonal magma systems; high-precision U–Pb zircon geochronology from the Organ Mountains caldera and batholith, New Mexico
The Organ Mountains caldera and batholith expose the volcanic and epizonal plutonic record of an Eocene caldera complex. The caldera and batholith are well exposed, and extensive previous mapping and geochemical analyses have suggested a clear link between the volcanic and plutonic sections, making this an ideal location to study magmatic processes associated with caldera volcanism. Here we present high-precision thermal ionization mass spectrometry U–Pb zircon dates from throughout the caldera and batholith, and use these dates to test and improve existing petrogenetic models. The new dates indicate that Eocene volcanic and plutonic rocks in the Organ Mountains formed from ~44 to 34 Ma. The three largest caldera-related tuff units yielded weighted mean [superscript 206]Pb/[superscript 238]U dates of 36.441 ± 0.020 Ma (Cueva Tuff), 36.259 ± 0.016 Ma (Achenback Park tuff), and 36.215 ± 0.016 Ma (Squaw Mountain tuff). An alkali feldspar granite, which is chemically similar to the erupted tuffs, yielded a synchronous weighted mean [superscript 206]Pb/[superscript 238]U date of 36.259 ± 0.021 Ma. Weighted mean [superscript 206]Pb/[superscript 238]U dates from the larger volume syenitic phase of the underlying Organ Needle pluton range from 36.130 ± 0.031 to 36.071 ± 0.012 Ma, and the youngest sample is 144 ± 20 to 188 ± 20 ka younger than the Squaw Mountain and Achenback Park tuffs, respectively. Younger plutonism in the batholith continued through at least 34.051 ± 0.029 Ma. We propose that the Achenback Park tuff, Squaw Mountain tuff, alkali feldspar granite and Organ Needle pluton formed from a single, long-lived magma chamber/mush zone. Early silicic magmas generated by partial melting of the lower crust rose to form an epizonal magma chamber. Underplating of the resulting mush zone led to partial melting and generation of a high-silica alkali feldspar granite cap, which erupted to form the tuffs. The deeper parts of the chamber underwent continued recharge and crystallization for 144 ± 20 ka after the final eruption. Calculated magmatic fluxes for the Organ Needle pluton range from 0.0006 to 0.0030 km3/year, in agreement with estimates from other well-studied plutons. The petrogenetic evolution proposed here may be common to many small-volume silicic volcanic systems
Spatial, seasonal and ontogenetic changes in food resource use by a piscivore fish in two Pantanal lagoons, Brazil
European Competition Policy in International Markets
International audienceChanges in the institutional, technological and economic environment raise new challenges to the European competition policy. In this context, it is timely for European authorities to appraise the external dimension of the European competition policy as well as its articulation with current internal reforms. Globalisation can increase the costs of monitoring and seriously reduce the ability of European authorities to tackle cross-border anti-competitive conducts. In addition, conflicts are exacerbated by industrial policy motivations. As it is unlikely that the sole application of the territoriality and extraterritoriality principles to competition rules could yield an optimal international competition system, globalisation calls for higher levels and types of cooperation. Given that bilateral cooperation and especially the implementation of comity principles could be of no value when laws or interests are sources of international conflicts, three main paths could be therefore encouraged: The continuous harmonization of rules through the joint action of OECD and ICN; the higher cooperation in the confidential information exchange; the establishment of global anti-trust institutions. Although WTO is legitimate in judging questions related market access and entry barriers, it is less equipped to assess international hard core cartels or M&A reviews. As a substitute for WTO, a multilevel system, like the EU system, could be promoted. For political and pragmatic reasons, it could be composed in a first step of a hard core of countries like the EU, Japan and the U.S. It could be associated with the creation of an international Court of Justice for competition. In addition to these external reforms, some internal reforms could be required. Competition authorities have to develop further competition advocacy to give a higher priority to competition issues in other EU policies and national regulation. A parallel and complementary reform could consist in making the European competition agency independent from State Members' interference
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