Detecção e recuperação de falhas para a máquina de redução de grafos PEWS-AM

Web services are software units that allow access to one or more resources, supporting the deployment of business processes in the Web. They use well-defined interfaces, using web standard protocols, making possible the communication between entities implemented on different platforms. Due to these features, Web services can be integrated as services compositions to form more robust loose coupling applications. Web services are subject to failures, unwanted situations that may compromise the business process partially or completely. Failures can occur both in the design of compositions as in the execution of compositions. As a result, it is essential to create mechanisms to make the implementation of service compositions more robust and to treat failures. Specifically, we propose the support for fault recovery in service compositions described in PEWS language and executed on PEWS-AM, an graph reduction machine. To support recovery failure on PEWS-AM, we extend the PEWS language specification and adapted the rules of translation and reduction of graphs for this machine. These contributions were made both in the model of abstract machine as at the implementation level

O problema do Hiker Dice em tabuleiro compacto: um estudo algorítmico

The Hiker Dice was a game recently proposed in a software designed by Mara Kuzmich and Leonardo Goldbarg. In the game a dice is responsible for building a trail on an n x m board. As the dice waits upon a cell on the board, it prints the side that touches the surface. The game shows the Hamiltonian Path Problem Simple Maximum Hiker Dice (Hidi-CHS) in trays Compact Nth , this problem is then characterized by looking for a Hamiltonian Path that maximize the sum of marked sides on the board. The research now related, models the problem through Graphs, and proposes two classes of solution algorithms. The first class, belonging to the exact algorithms, is formed by a backtracking algorithm planed with a return through logical rules and limiting the best found solution. The second class of algorithms is composed by metaheuristics type Evolutionary Computing, Local Ramdomized search and GRASP (Greed Randomized Adaptative Search). Three specific operators for the algorithms were created as follows: restructuring, recombination with two solutions and random greedy constructive.The exact algorithm was teste on 4x4 to 8x8 boards exhausting the possibility of higher computational treatment of cases due to the explosion in processing time. The heuristics algorithms were tested on 5x5 to 14x14 boards. According to the applied methodology for evaluation, the results acheived by the heuristics algorithms suggests a better performance for the GRASP algorithm

Interação gestual em ambiente residencial: estudo, concepção e desenvolvimento

Control and automation of residential environments domotics is emerging area of computing application. The development of computational systems for domotics is complex, due to the diversity of potential users, and because it is immerse in a context of emotional relationships and familiar construction. Currently, the focus of the development of this kind of system is directed, mainly, to physical and technological aspects. Due to the fact, gestural interaction in the present research is investigated under the view of Human-Computer Interaction (HCI). First, we approach the subject through the construction of a conceptual framework for discussion of challenges from the area, integrated to the dimensions: people, interaction mode and domotics. A further analysis of the domain is accomplished using the theoretical-methodological referential of Organizational Semiotics. After, we define recommendations to the diversity that base/inspire the inclusive design, guided by physical, perceptual and cognitive abilities, which aim to better represent the concerned diversity. Although developers have the support of gestural recognition technologies that help a faster development, these professionals face another difficulty by not restricting the gestural commands of the application to the standard gestures provided by development frameworks. Therefore, an abstraction of the gestural interaction was idealized through a formalization, described syntactically by construction blocks that originates a grammar of the gestural interaction and, semantically, approached under the view of the residential system. So, we define a set of metrics grounded in the recommendations that are described with information from the preestablished grammar, and still, we conceive and implement in Java, under the foundation of this grammar, a residential system based on gestural interaction for usage with Microsoft Kinect. Lastly, we accomplish an experiment with potential end users of the system, aiming to better analyze the research results

A biotecnologia e a educação ambiental no resguarde a duas espécies em vias de extinção na flora da Mata Atlântica Brasileira

The anthropical action caused destruction of great part of the Atlantic forest remaining today around 7% to 8% of the original portion. A classical example of the degradation is the situation of the Pau-Brasil (Caesalpinia echinata Lam.) which appellant exploration summarized abruptly decreased the wild occurrence of the species. Besides the economic exploration and the threat of extinction, the plant shows some characteristics that its own physiology makes difficult the survival in natural conditions. For this reason, any strategy developed to conserve it should also guarantee ways for its multiplication. In these conditions, the only reasonable technology is micropropagation in vitro based on immature segments of Catullus (explants or internodes). However, in virtue of the threat of extinction, extractivism and fenology, the disponibility of the sources of explants are reduced. Then, to turn this around, the present research showed the hypothesis that arrange these explants would have as a solution to elaborate a bank of matrixes and the utilization of produced seedlings as source of explant. Then, assuming that the soil is a fundamental element for a good formation of the seedlings, there were tests in a greenhouse on the Laboratory of plant biotechnology at UFRN, from May to June of 2008 that showed the influence of the four different soils on the production of Pau-Brasil. The objective of this work was to make possible the seedlings production of the specie and from them to establish a bank of matrixes as source of explant to guarantee the continuity of the process of micropropagation, contributing with the preservation of the specie

Viabilidade da cultura Cnidoscolus quercifolius POHL para produção de Biodiesel no semiárido nordestino

The northeastern semiarid is a region that presents a serious picture stagnation or slowness of the economic growth, beyond the presence of social pointers below of the averages national and regional. The half-dryness conditions become the improper region for many agricultural cultures, what it affects the local populations directly, as well as the economy that is based mainly on agriculture. Cnidoscolus quercifolius Pohl, popularly know as favelone is a native species of the semiarid region that withholds great potential for the development of the region in virtue of its multiple uses. Being an oleaginous, its production in familiar farmings makes with that biodiesel either for the misery an important alternative eradication for the possibility of occupation of enormous contingents of people. The present study it aims at to evaluate the germination of the faveleira without thorns under conditions of water and saline stresses, main stresses which the vegetal species of the semiarid one are submitted; beyond verifying the acceptance of the species for agriculturists of a cooperative in the city of Apodi/RN. The methodology used for germination corresponds to using treatments with polyethylene glycol and sodium chloride to assess water and salt stress respectively, being held in rolo. O system approach used for the verification of acceptance of faveleira was the use of interview with farmers cooperative in the study area determined. In this direction it was verified that the faveleira is a resistant species the conditions of drought and salinity of the ground, factor of great relevance, since one is about a species with high added value, making possible the development for the semiarid region. It was verified that the agriculturists are favorable the introduction of the faveleira and reveal receptive the idea to cultivate a species with potential for production of biodiesel

Biomonitoramento da qualidade da água e ações em educação ambiental em dois açudes da bacia hidrográfica Apodi-Mossoró, RN

Water scarcity is a reality for the inhabitants of the Brazilian semiarid region. The problem, in quantitative terms , is caused due to local climatic conditions due mostly to a water deficit. Qualitatively, results of multiple uses and resulting contamination by human activities. Eutrophication is presented as a threat to the sustainable use of water resources, in order to favor the predominance of dense populations of cyanobacteria, which can be potentially harmful to human health. The aim of this study is to understand the population dynamics of phytoplankton and cyanobacteria to assess water quality of reservoirs Santa Cruz do Apodi and Pau dos Ferros belonging to bacia Apodi Mossoró-RN . Water samples were collected monthly between October 2011 and May 2012 in reservoirs Santa Cruz do Apodi and Pau dos Ferros, in this latter , in Jan/12 we performed a diel profile . The abiotic variables obtained in the field and in the laboratory were: water temperature , dissolved oxygen , pH , turbidity , transparency , total nitrogen and total phosphorus . Phytoplankton samples were collected with a plankton net and bottle of Van dorn . Were performed : identification , quantification , calculation of biovolume , classification into functional groups and index calculation phytoplankton assembly ( Q ) , cyanotoxins were quantified by ELISA . Statistical analyzes supported the evaluation of the dynamics between biotic and abiotic factors. A questionnaire was conducted to examine the conceptions of the population, education professionals and students. The reservoir of Pau dos Ferros, shallow , turbid and eutrophic showed dominance of the functional group SN throughout the sample period . The phytoplankton biomass ranged from 20 to 70 mm ³ . L - 1, the lowest values coincided with the increase of the mixing zone and transparency, which contributed to the occurrence of a change in species composition phytoplankton . The application of the index Q proved relevant, the reservoir of Pau dos Ferros , depending on the species present , was classified ecologically as bad for almost the entire sample period . The reservoir Santa Cruz do Apodi showed low biomass ( 0.04 and 4.31 mm ³ . L - 1 ) and greater diversity in the phytoplankton composition . According to the index assembly (Q ), it showed moderate condition during most of the period influenced by different functional groups of typical meso- eutrophic environment (K S0, H1, C, F , J , E, D and N) . Associations of diatoms and green algae D and X1 succeeded populations of cyanobacteria in periods marked by greater instability in the system , caused by wind or rain. In summary , the occurrence of drought has a direct influence on the hydrological conditions of the reservoirs , in general, these events, reducing the reservoir level is directly related to decreased water quality and increased density of phytoplankton occurring predominance of cyanobacteria , the index Q reflected well to changes in phytoplankton composition , being a good indicator for biomonitoring of reservoirs in this study and survey of previous conceptions showed the need to work on environmental awareness for the preservation of water resources by conducting workshops for Environmental Education

Análise da mobilidade urbana de Natal/RN a partir do uso de indicadores de sustentabilidade

In contemporary times, the urban mobility is presented as one of the main challenges of large and medium-sized Brazilian cities , it presents signs of unsustainability , above all due to the increase in motorized transport system , especially the individual . Thus , it is clear that mobility is considered of special interest for sustainable urban development , is facing a crisis that is reflected in negative externalities , particularly with regard to congestion , accidents , air pollution , social exclusion , among others. The complexity of these problems requires an integrated analysis based on the principles of sustainability . In this sense , trying to understand this problem and in the attempt to minimize its impacts, Costa (2008 ) proposed the Index of Sustainable Urban Mobility (I_SUM) with the goal of providing a methodology capable to assess relevant aspects of mobility , including social dimensions , political, economic and environmental . Given the above, was elected as the main objective of this study is to analyze urban mobility in Natal / RN from the perspective of sustainability . Like specific objectives will seek to analyze Natal´s urban mobility, using the I_SUM like a tool for both the city as a whole and for each of its four administrative regions; evaluate Natal s urban accessibility conditions and verify to what extent the access to urban services and equipment is facilitated or hindered because of the location and incomes of the population . For this, it was necessary to use bibliographic , documentary and field research . The index , which varies from 0.00 to 1.00, revealed for Natal an Global value of 0,510, and that refers to its administrative regions, it was found that there are very small percentage differences from the overall index calculated for the city . The performance of I_SUM by administrative region showed that although there are differences , the results were very similar , varying between 0,494 and 0,537. Particularly in relation to urban accessibility, it appears that Natal presents as an unequal city and this inequity , which is not only income is reflected in the issues related to accessibility and hence urban mobility

Proteção constitucional do consumidor no âmbito da regulação publicitária

The concern with issues related to consumer protection has emerged in North America and then spread throughout the world. In Brazil, consumer‟s rights and interests only gained greater importance after their consolidation in the Constitution of 1988 and the enactment of the 8078/90 Law (Consumer‟s Protection and Defense Code), which established the consumerist microsystem. The understanding of the legal relationship of consumption concept is necessarily connected to knowledge of the elements that compose it. Among these, we can find the consumer and the provider (subjective elements), the product or service (objective elements), and the consumer‟s condition as final receiver of the consumption object (finalistic element). In order to elucidate the configuration of consumer protection before advertising communication, this work will analyze the advertising through the prism of consumerist laws, conceptualizing it and presenting a differentiation of it in relation to practices such as marketing, offer and commercial communication as well as examining its several kinds of manifestation, focusing mainly the ones categorized as misleading or unfair advertising. All kinds of advertising communication against the consumerist microsystem are subject to judicial control exercised by the State. Besides individual protection possibilities, this state-owned control can be collectively exercised as a result of the utilization of public civil action and popular action. Some specific categories of advertising (smoking products, alcoholic beverages, pesticides, medicines and therapies) are still subject to a set of particular restraints provided by the 9294/96 Law, which enables the performance of a special control in relation to them. In addition to state control, there is also a system of advertising communication self-regulation, which develops itself through the actions of the National Council of Advertising Self-Regulation that are based mainly on the laws established by the Brazilian Code of Advertising Self-Regulation and its annexes. However, this system of advertising self-regulation still has some deficiencies that hinder its effectiveness

Caracterização dos sedimentos superficiais de fundo do complexo recifal de Maracajaú

The study carried out in the environment of Maracajaú reef an São Roque channel, had as main objective to analyze the characteristics of sediments active locally expressed in the grains, through collections of sediments in the field, technical processing and data analyzes of sediments. Data processing were made on three main aspects: biotic composition, concentration of calcium carbonate and particle size of the sediment. Differences between the sediments of the reefs and channel were observed. It was emphasized the contribution of algae limestone in the production of carbonate, with some influence of foraminifera near the coast. The particle size distribution presented significant results for the understanding of locally sedimentary deposits. The results showed an environment of carbonate, with predominance of algae limestone, associated to unconsolidated sediments with gross granularity, besides the presence of rhodoliths in all samples.The fragmentation of biotic components and the prevalence of elliptical rhodoliths with little or no branch, indicate an environment of high energy hydrodynamics. This work is a further contribution to the understanding of sedimentology active locally in reef environments, in particular the of Maracajaú reef, by virtue of their complex ecosystem composed of a diversity of wild fauna and flora that still little studied in Brazil comparing to accelerated growth of teeth extractions and usufructs of natural resources causing often irreversible impacts to the environment

Caracterização morfológica e sedimentar do talude continental (foz do Amazonas)

Created on 3 december 1997, the REMPLAC (Program for Assessment of Mineral Potencial of the Continental Shelf), this porgram aimed to make the basic survey, systematic geological and geophysical continental shelf, detail, at an appropriate scale, sites geo-economic, and perform the analysis and evaluation of mineral deposits. The REMPLAC should continue the efforts of Global Recognition Program of the Brazilian Continental Margin REMAC closed in 1978, the operations Geophysical Sea (GEOMAR) developed by the Directorate of Hydrography and Navigation and the various initiatives of the Program of Marine Geology and Geophysics (PGGM). Despite the high interest on the Amazon platform, there is little information o their morphology and sediment characterization, and in order to fill this gap, the present work samples sedimentological point followed by seismic acquisition. And the studies were to characterize the possible area of interest as being directly influence by tides, which sediments are reworked throughout the platform featuring grain angle with sharp corners, and the carbonate content increases as it approaches the breakdown the platform, and the bodies found outside the foraminifera and mollusks. However, diverging with organic matter that reduces its concentration as it moves away from the coast. The seismic profiles do not get satisfactory results because of low visibility, however, to correlate with the spot samples, of sediment were possible morphological characterization of the area.

Alterações dos parâmetros climáticos no município de Apodi-RN, antes e após a construção da barragem Santa Cruz do Apodi, e formação do lago

Este trabalho teve como objetivo principal analisar as mudanças ocorridas no clima local onde o município de Apodi/RN está inserido, em virtude da construção da Barragem Santa Cruz do Apodi. Foram utilizadas para o tratamento dos dados climáticos precipitação pluviométrica, umidade relativa do ar e temperatura técnicas estatísticas como Desvio Padrão, Teste T, Coeficiente de Variação e Média aritmética, além do modelo matemático. Para o balanço hídrico foi aplicado o método de Thornthwait (1948), considerando dois períodos em análise: o anterior e posterior a construção da Barragem Santa Cruz do Apodi, respectivamente 1995 e 2005. os resultados obtidos permitiram inferir que a hipótese inicial levantada se confirma, ou seja, a construção da Barragem Santa Cruz do Apodi, está influenciando diretamente numa alteração no que concerne à condição atmosférica local, especialmente no parâmetro umidade relativa do ar. Quanto ao balanço hídrico, observou-se a predominância do déficit hídrico especialmente entre os meses de junho a janeiro, período de estiagem; um excedente ocorrente entre os meses de maio e junho, conseqüente do período chuvoso; e uma reposição hídrica antecedendo e sucedendo este período, chuvoso, ou seja, compreendendo os meses de fevereiro a junho. Todas as considerações e análises poderão contribuir para o planejamento de abastecimento d´água, a irrigação, auxílio na previsão de enchentes e estiagens, bem como o manejo do uso da água subterrânea

Condições de trabalho e terceiro setor: implicações contemporâneas para o serviço social

In the contemporaneity, due to the implementation of the neoliberal project in which one verifies the withdrawal of the State in regard to the development of social policies, it is observed a new way of responding to the multifaceted expressions of the social issue, which is the emergence and expansion of a supposed "third sector" in society. Thus, the productive restructuring process has led to the deterioration of labor relations, as well as a super exploration of human labor power, also triggering structural unemployment. By being delineated in classist interests, the emergence of the "third sector" brings contradictory aspects to the society, one of these being the very concept of "third sector", more ideological than real. By seeking to answer the expressions of the social issue, demands the intervention of social workers in the institutions that "composes it". This way, arises the interest in researching what are the current conditions and labor relations of the social workers who work in the institutions of the "third sector" in Mossoró-RN. Therefore, this study is constituted by a survey for the conclusion of a Master's degree in Social Service at the Universidade Federal do Rio Grande do Norte. Therefore, it was listed out as general objective to identify and analyze the conditions and labor relations of the social workers entered in the institutions of the "third sector" in Mossoró-RN. And by specific objectives: to map the institutions that are part of the "third sector" in the city of Mossoró, which have social workers on its professional staff, in order to profile the same; and, analyze the main challenges presented to the work of the social worker in these institutions. We used the bibliographic and documental research to enlighten the knowledge of the topic approached and the development of the field research, in which for the analysis of the data obtained, through field research, it was used the quantitative and qualitative approach. The search results confirmed that half of the institutions was identified as philanthropics, and most of them are funded by the federal government and that such organizations develop activities in several areas, particularly health and welfare. Concerning the conditions and labor relations, was highlighted the fact that half of the professionals insert themselves within the institutions by appointment; regarding the salary, 57.1% of employees receive between 3 and 4 minimum wages, which is considered relatively low. Was satisfactory the analysis related to the labor rights, because almost all offer a formal contract, which ensures, in great measure, the effectuation of such rights. Now with regard to the workload, 5 of 6 institutions implemented the Law Nº. 12.317/2010 ensuring 30 hours a week for social workers. However, it were cited many challenges relating the reality of the "third sector" to the conditions and labor relations, among them stands out: the delay of salary and non-salary adjustment; the realization of activities that do not relate to professionals, functions and duties; the development of many activities by a single professional. Two important data are the not incentive to a postgraduate and the charging of the fulfillment of the goals for the professional productivity. Here, it is worth to reflect that, although this study presents elements that provide to identify some aspects of labor relations and conditions of social workers in the "third sector" in Mossoró- RN, as well as some challenges that permeate this space of professional insertion, is meant that there is much to be unveiled, and other studies can later do so in an attempt to a better understanding of the complexity of processes that permeate the "third sector"

(Santa) Rita de Cássia na boca do povo de Santa Cruz/RN: identidades culturais em construção

The purpose of this study is to investigate the cultural identities of Santa Rita de Cassia constructed from the representations contained in the speech of Santa Cruz urban area residents, which is located in a harsh part of the State of Rio Grande do Norte. These residents make the story of the Saint full of meaning for themselves, in their daily lives, as well as to the society. This is observed in the narration of Rita de Cassia’s story which has been told in the city over the past one hundred and eighty years, the number of women's names and commercial establishments named “Santa Rita”. In 2010, with the inauguration of the Alto de Santa Rita – a space for worshiping the saint –, the amount of visitors increased in the city, due to the construction and inauguration of a colossal monument representing the image of Rita de Cassia. Then, new social, cultural, religious and political aspects became part of the local reality of the city of Santa Cruz, what made residents have something in common to talk about. According to the interdisciplinary approach of Applied Linguistics, our theoretical background is based on the socio-historical language concept, which understands language as discursive practice. Still theoretically speaking, this study establishes an interface with cultural studies, taking into account the concept of cultural identity in post-modernity society. Discourse analysis proved plural, with a multiplicity of cultural identities ranging from very obedient daughter to wife who suffered because of the husband, from very religious woman to the widow who entered the convent, on to the Saint of the miracles and healings interceding in the lives of the ones who seek for help. It was also observed in the above mentioned investigative path that these identities can be constructed and reconstructed if immersed in a different set of social practices historically determined

A cidadania no contexto do estado constitucional democrático de direito brasileiro

The citizenship is a fundamental category to the democratic progress and the development and concretization of human rights, in addition to being one of the essential foundations of democratic contextualized in the rule of law of the Federative Republic of Brazil. That’s exactly why the discussion about its concept and content is a paramount requirement to the understanding and interpretation-application-concretization of the Federal Constitution of 1988, as well as its democracy, since there is no democracy without citizenship. That is why the general objective of the research is to determine the characteristics of the citizenship, relating it to the Law, as well as to discuss (critically) its inclusion in the list of fundamental rights and delimitate the scope of protection and the limits of this right, in the context of Brazilian law post-1988 Constitution. The specific objectives are: a) to analyze the concept of citizenship, its extent and scope, contextualizing it historically; b) to examine the evolution of the legal and regulatory treatment of the citizenship in Brazilian constitutions, focusing on the 1988 Constitution; c) assess whether citizenship can be considered a fundamental right; d) to investigate which implications, theoretical and practical, of assignment fundamentality character to the right to citizenship. This research identifies and deconstructs current conceptual confusions, such as the lack of distinction between citizenship and nationality; citizenship and electoral capacity; citizenship and person. It also helps to identify and oppose the generalizations, as well as the excessively abstract associations which tend to purely metaphysical understandings, fluid and empty of any content. The main virtue, however, is the proposed of understanding of the citizenship as a fundamental right and the examination of the relationship between citizenship and human dignity. In this context, citizenship appears as a corollary of human dignity and it goes beyond. This (human dignity) requires equality, non-arbitraries, non-excessive, disproportionate or unreasonable impositions affecting their freedom rights, and, yet, doesn’t affect a minimum core of possibilities of have to a decent life, in conditions of freedom and self-conformation involved in the necessary consideration of the individual as a subject. All of this requires a decision-making process, molded by the citizenship, which reaches the entire development process of possible state interventions, to ensure the person as a subject, the right holder and the objective point of reference of the juridical relations. Thus, the citizenship represents a substantial and beneficial addition to the human dignity, since the emancipated citizen is a person, formally and materially, qualified, to be able to build their own and collectively organized history, to participate effectively in the making processes decision juridical and social

Características estruturais e fotocatalíticas do compósito oxihidróxido de nióbio/vermiculita

The preparation of nanostructured materials using natural clays as support, has been studied in literature under the same are found in nature and consequently, have a low price. Generally, clays serve as supports for metal oxides by increasing the number of active sites present on the surface and can be applied for various purposes such as adsorption, catalysis and photocatalysis. Some of the materials that are currently highlighted are niobium compounds, in particular, its oxides, by its characteristics such as high acidity, rigidity, water insolubility, oxidative and photocatalytic properties. In this scenario, the study aimed preparing a composite material oxyhydroxide niobium (NbO2OH) / sodium vermiculite clay and evaluate its effectiveness with respect to the natural clay (V0) and NbO2OH. The composite was prepared by precipitation-deposition method and then characterized by X-ray diffraction, infrared spectroscopy (XRD), energy dispersive X-ray (EDS), thermal analysis (TG/DTG), scanning electron microscopy (SEM), N2 adsorption-desorption and investigation of distribution of load. The application of the material NbO2OH/V0 was divided in two steps: first through oxidation and adsorption methods, and second through photocatalytic activity using solar irradiation. Studies of adsorption, oxidation and photocatalytic oxidation monitored the percentage of color removal from the dye methylene blue (MB) by UV-Vis spectroscopy. The XRD showed a decrease in reflection d (001) clay after modification; the FTIR indicated the presence of both the clay when the oxyhydroxide niobium to present bands in 1003 cm-1 related to Si-O stretching bands and 800 cm-1 to the Nb-O stretching. The presence of niobium was also confirmed by EDS indicated that 17 % by mass amount of the metal. Thermal analysis showed thermal stability of the composite at 217 °C and micrographs showed that there was a decrease in particle size. The investigation of the surface charge of NbO2OH/V0 found that the material exhibits a heterogeneous surface with average low and high negative charges. Adsorption tests showed that the composite NbO2OH/V0 higher adsorption capacity to remove 56 % of AM, while the material removed from V0 only 13 % showed no NbO2OH and adsorptive capacity due to the formation of H-aggregates. The percent removal of dye color for the oxidation tests showed little difference from the adsorption, being 18 and 66 % removal of dye color for V0 and NbO2OH/V0 respectively. The NbO2OH/V0 material shows excellent photocatalytic activity managing to remove just 95,5 % in 180 minutes of the color of MB compared to 41,4 % and 82,2 % of V0 the NbO2OH, proving the formation of a new composite with distinct properties of its precursors.