Políticas sociales y cambio social en América Latina y la Región Andina: alcances y perspectivas

Entre 1982 e inicios del actual mileno, las políticas sociales en América Latina, y la región andina en particular, estuvieron inspiradas en el Consenso de Washington, y guiadas por tres ideas dominantes: a) el mecanismo fundamental de reducción de la pobreza es la promoción del crecimiento económico, b) la inversión en educación y salud debe contar con una alta participación del sector privado, y c) se deben implementar transferencias condicionadas de dinero y programas asistenciales para los más pobres (Solimano, 2005). Estas líneas se insertaron en una política económica que buscó la minimización de la intervención del Estado en la economía, la promoción de mecanismos de mercado para el crecimiento y la apertura comercial internacional. En general, el crecimiento económico de la región fue mínimo e inestable, la pobreza mantuvo niveles persistentes y la inequidad social se profundizó, aunque se registraron avances moderados en educación y salud. A partir de mediados de la década anterior, se observan dos cambios fundamentales. Por una parte, la región retoma un crecimiento económico relativamente sostenido, basado en la expansión de sus exportaciones de bienes primarios y en una mejora sustancial en los términos de intercambio. Adicionalmente, cambia la concepción de las políticas sociales en muchos países, y el nuevo enfoque se basa en un aumento significativo de la inversión pública en educación, salud y seguridad social, en la aceptación más amplia de un enfoque universal de las políticas sociales basadas en la noción de derechos, y en la consolidación de programas de transferencias monetarias condicionadas. Los resultados alcanzados durante los últimos 10 años son alentadores en términos de reducción de pobreza, aumento de la equidad social y mejoras en educación, salud y empleo. Estos avances, al parecer, se registran en la mayor parte de los países, y la orientación política de sus gobiernos no juega un rol importante como factor diferenciador. Desafortunadamente, el escenario positivo para el crecimiento económico de la región comienza a agotarse, principalmente como resultado del menor impulso económico en China, la reducción del crecimiento de la economía mundial y del menor dinamismo en la demanda de ciertas materias primas, que ha conducido a una nueva declinación en los términos de intercambio. Los resultados alcanzados por la región en términos de diversificación económica son muy poco alentadores, y en varios países han aparecido manifestaciones importantes de descontento social e inestabilidad económica. Este artículo analiza, en el caso de los países andinos, los resultados sociales alcanzados a partir de 2004, su relación con la orientación política de sus gobiernos, y sus perspectivas de continuidad bajo un nuevo escenario internacional menos favorable. Se analiza con mayor profundidad la experiencia ecuatoriana.

Integración andina y convergencia suramericana

El 19 de septiembre de 2013 los ministros de relaciones exteriores de los cuatro países miembros de la Comunidad Andina (CAN) expidieron la Decisión 792, norma comunitaria jurídicamente vinculante, mediante la cual pusieron en marcha un proceso de “reingeniería” del Sistema Andino de Integración2 (SAI). El aspecto más resaltado por la prensa fue una supuesta determinación de suprimir al Parlamento Andino, órgano deliberante del SAI. En realidad, la norma aprobada plantea su paulatina salida del Sistema, presumiblemente con miras a su migración hacia el Parlamento Suramericano por establecerse en el marco de la Unión de Naciones Suramericanas (UNASUR)3, pero también dispone evaluar la permanencia en el SAI de la Corporación Andina de Fomento (CAF), el Fondo Latinoamericano de Reservas (FLAR) y el Organismo Andino de Salud. Sin subestimar la trascendencia e implicaciones de estas resoluciones que afectan a cuatro importantes instituciones comunitarias, lo que importa destacar aquí es que la Decisión 792 marca el inicio de un proceso de amplias reformas al esquema y al proceso andino de integración.

Repeated administration of caffeine increases femproporex-induced locomotor activity in adolescent and adult rats

Caffeine and femproporex are psychostimulants drugs widely consumed in Brazil. Behavioral sensitization is defined as an augmentation in the behavioral effect of a psychostimulant upon re-administration. Repeated administration of a psychostimulant produces behavioral sensitization to that drug and cross-sensitization to other drugs. We investigated whether repeated administration of caffeine increases femproporex-induced locomotor activity in adolescent and adult rats. Forty-eight adolescent (postnatal day 27) and 32 adult (postnatal day 60) received i.p. injections of caffeine (CAF) (10.0 mg/kg) (adolescent N = 24; adult N = 16)) or saline (adolescent N = 24; adult N = 16) once daily for ten days. Three days following the last injection each group was subdivided and received a challenge injection of femproporex (2.0 mg/kg i.p) or saline. Locomotor activity was recorded for 1 hour in 5 - minute intervals. Our results showed that repeated injections of caffeine increased femproporex - induced locomotor activity in adult and adolescent rats.

Occupational exposure to radon and natural gamma radiation in the La Carolina, a former gold mine in San Luis Province, Argentina

Radon and gamma radiation level measurements were carried out inside the La Carolina mine, one of the oldest gold mining camps of southern South America, which is open for touristic visits nowadays. CR-39 track-etch detectors and thermoluminescent dosimeters of natural CaF(2) and LiF TLD-100 were exposed at 14 points along the mine tunnels in order to estimate the mean (222)Rn concentration and the ambient dose equivalent during the summer season (November 2008 to February 2009). The values for the (222)Rn concentration at each monitoring site ranged from 1.8 +/- 0.1 kBq m(-3) to 6.0 +/- 0.5 kBq m(-3), with a mean value of 4.8 kBq m(-3), indicating that these measurements exceed in about three times the upper action level recommended by ICRP for workplaces. The correlations between radon and gamma radiation levels inside the mine were also investigated. Effective doses due to (222)Rn and gamma rays inside the mine were determined, resulting in negligible values to tourists. Considering the effective dose to the mine tourist guides, values exceeding 20 mSv of internal contribution to the effective doses can be reached, depending on the number of working hours inside the mine. (C) 2009 Elsevier Ltd. All rights reserved.

Simultaneous Differential Pulse Voltammetric Determination of Ascorbic Acid and Caffeine in Pharmaceutical Formulations Using a Boron-Doped Diamond Electrode

A cathodically pretreated boron-doped diamond electrode was used for the simultaneous anodic determination of ascorbic acid (AA) and caffeine (CAF) by differential pulse voltammetry Linear calibration curves (r = 0 999) were obtained from 1 9 x 10(-5) to 2 I x 10(-4) mol L(-1) for AA and from 9 7 x 10(-6) to 1 1 x 10-4 mol L(-1) for CAF. with detection limits of 19 wool L(-1) and 7 0 mu nol L(-1). respectively This method was successfully applied for the determination of AA and CAF in pharmaceutical formulations. with results equal to those obtained using a HPLC reference method

Omslagstrender - en studie av vad som höjer uppmärksamhetsvärdet hos tidskrifter

Through interviews, a questionnaire survey and an in­depth analysis of the Swedish magazines Veckorevyn and Magazine Café has a number of parameters been made visible. It was difficult to obtain an unambiguous result when the journal's target audience is crucial for the cover design. Nevertheless, we can generally say that the transparent varnish of covers, PMS colors and enclosing the journal in plastic do not increase the attention value, as this occurs in many magazines. Due to today's tough competition among journals, we believe that they will need to niche themselves much harder to survive. We also believe that the new, big trend is that more covers will become more plain and stylistically pure, with one big communicating image and fewer coverlines, as many covers were designed during the 1940s.

Hur ett företag kan uppmärksammas genom en grafisk profil och en gerillamarknadsföring

The purpose of this thesis was to create a visual identity to the café Trädgårdscafét. This was to increase the awareness of the cafe among the population of Borlänge. To make the company's visual identity visible, we also organized a guerrilla marketing. The outcome of the guerrilla marketing were then measured by calculating the number of guests during a certain period of time and also through a survey conducted in Borlänge.Graphic material, such as a graphic identity, business cards, feel good-cards, store signs, standing information folders to place on the tables and pavement board was created. Flyers and posters were also created for the guerrilla marketing. The basis for this was established in the study of literature, focus groups and surveys. We also kept a regular and open contact with the café owners throughout the project.In a similar procedure a broad knowledge about guerrilla marketing was gathered in order to be able to arrange one our selves.The guerrilla marketing was held for one day in the city of Borlänge. To attract attention, groups of outdoor furniture, decorated with green plants, were placed at different locations, while six marketers handed out flyers and spread information about the café. The guerrilla marketing resulted in that the café's customers grew by nearly twice as many on the day of the guerrilla. Surveys made before and after the guerrilla showed that the awareness of the café grew.

Orka hela vägen : Upplevd hälsa, idrotts- och träningsbakgrund bland studenter på en fysiskt inriktad yrkesutbildning. Lärarstudenter GIH 2008 delrapport 1: 2009

Sammanfattning Ett sammanfattande porträtt av den nyantagna lärarstudenten vid GIH med utgångspunkt från enkätsvaren ger vid handen en bild av en person, som är ca 21 år gammal, född i Sverige och uppvuxen i en medelstor stad i Mellansverige. Studenten trivdes mycket bra i skolan och var som elev något över medel med MVG i idrott och hälsa. Valet av yrkesutbildning grundade sig på ett stort intresse för idrott, samt en önskan att få jobba med barn och ungdom. Studievalet hade för många påverkats av en tidigare idrotts-lärare, kompisar och familj. En bra lärare i idrott och hälsa är enligt studenten positiv, engagerad, rättvis, bestämd och kunnig. Lärarstudenten ser sig behärska bollspel väl. Störst kunskap och färdighet uppges i fot-boll och alpin skidåkning. Minst kunskap och färdighet skattades i softboll, baseboll, bergsklättring, långfärdsskridskoåkning och i konsten att kunna valla skidor. Många ser sig ha god kunskap om sambandet mellan hälsa, livsstil och miljö, men mindre god om hur en idrottsaktivitet har betydelse för kulturarvet, samband mellan miljö och männi-skans hälsa i ett historiskt och nutidsperspektiv samt i ergonomi. På sin fritid går lärarstudenten ofta på idrottsevenemang, café, tittar på TV och video eller umgås med vänner och familj. Lärarstudenten går sällan på bio och nästan aldrig på tea-ter, museum eller vernissager. "Vad är vernissage?" undrar en student. Hälsan, både fysiskt och psykiskt, skattas som tillfredsställande och man känner ofta hopp, glädje och meningsfullhet. Emellertid finner man sig även ofta stressad på grund av tidsbrist och alla krav. Många kvinnliga studenter (41%) rapporterade ryggont och många, både kvinnor och män, beskrev att de har besvär från en skadad fotled eller knä. De flesta lärarstudenterna är regelbundet fysiskt aktiva och de finner att mängden motion delvis är tillfredsställande. Förväntningarna är höga på utbildningen både att den är mångsidig och kommer att ge ökad kunskap inom olika områden. Under studietiden förväntar man sig att utvecklas och förbättra sin egen fysiska status och hälsa. En student uttrycker det med orden: "Mitt nya liv startar idag". Den sammanfattande bilden av lärarstudenten på GIH liknar den som tidigare har redovisats av Meckbach och Wedman i en liknande studie från maj 2005. Deras studie genomfördes på studenter efter ett års studier på GIH (Meckbach & Wed-man, 2007).

PANA V : Evaluation of a Literacy Project

PANA V Evaluation of a Literacy ProjectSUMMARY AND CONCLUSIONSThis evaluation set out to explore the impact of the literacy work carried out through PANA V. It focussed on clarifying effects such as empowerment and poverty reduction in relation to the civil society. Two specific objectives were to evaluate the methodological approach and the didactic materials and to evaluate the sustainability of the project.Although the focus of the evaluation has been PANA V, the project has been evaluated in its context, as one in a series of five projects located in Rwanda ten years after the war and genocide. The conclusion will consider future plans in this field.The evaluator has striven to create a holistic picture of the effects of the project, although the given time for the evaluation was short. Only three weeks were spent in the field study and only ten days in the actual field. Although there were some organisational and logistic problems, as is common when carrying out a study like this in a poor country, many literacy sites were visited and quite many participators were interviewed. The overall impression from the study is overwhelmingly positive. So many people commit themselves in this task of teaching Rwandans reading, writing and numeracy. Despite harsh conditions learners strive to learn and group leaders devote themselves to the task. Many leaders on different levels try their very best to manage their difficult and demanding task. The main objective was to explore the impact of the project on poverty reduction, particularly on empowerment and strategies for everyday life. Women were to be regarded particularly. From the results it is clear that the project has a strong, positive impact both on poverty reduction and empowerment of marginalised groups. Among those who have benefited from the alphabetisation are mainly women. Unfortunately, when it comes to leaders in PANA, who may also be said to have benefited from the project, only a small minority is women. This is something that is recommended that it be reconsidered inside the organisation. As a majority of the targeted learners are women, and as the economic and social situation of women in Rwanda is generally weak, this is a question that I recommend the Pentesostal church and ADEPR to look particularly into. With many women being single breadwinners of their households, it is important that also women get access to positions that may bring benefits of different kind.It is also clear that the project has positive effects for the civil society. In the present situation in Rwanda, during the process of reconciliation and rapid progress, basic education for the poor majority is a democratic issue. In a country with a plethora of internet-cafés in the capital and a small minority that use cars and mobile-telephones to communicate nation-wide, it is of outmost importance that the majority acquires basic education, of which literacy is a central part. To strengthen the civil society in Rwanda literacy is important. One central issue is then that Rwanda develops toward becoming a country where literacy is used for the benefit of the citizens and it is a democratic issue that all citizens get an opportunity to participate. Crucial for this is that strong efforts are put into primary schools nation-wide. Literacy projects for adults, like PANA, may only complement these efforts, but they constitute important and necessary complements. Other relevant ways to promote literacy are campaigns in Radio and TV and through cultural events such as festivals, music and theatre. News papers, magazines and books are natural parts of such campaigns as well as adult education. As stated under the results not much can be said about the didactics in this evaluation. On the whole the methodology and the materials fill their function well and receive a high reputation. As people learn to read and write under very simple conditions, obviously the approach is appropriate. A few suggestions may be given from the study:•Focus groups leaders’ attention on clearness, that they show very clearly what is to be read. Good structuring is probably of great importance for many learners.•Make clear what is tested in the tests and consider the possibility to use a holistic test that would be more congruent with the methodology. The possibility to use only one grade, pass, would enable a more practical test, such as reading a short, relevant text, writing something relevant and solving practical mathematic problems. Avoid tests that demand school knowledge.•Avoid using methaphors such as “fight against illiteracy” and connections between illiteracy/literacy and darkness/light. It is not true that illiteracy causes bad things and that literacy only brings good. •Be prepared that it may be more difficult in the future to achieve the goals as it may be the case that the early learners where the ones who achieved easily. The goal of “literacy in six month” in PANA will probably hold only for some learners but also those who do not manage in six months need literacy skills.A third objective was to secure sustainability. As for sustainability of the project in itself, and of the literacy process, the main conclusion is that there is a good potential. The commitment and devotedness among many involved in PANA proves good. One weakness is individual leaders in ADEPR who do not see this as an important task for the Pentecostal church in Rwanda. Other weaknesses are the unwillingness to mention explicitly the wish, for example among group leaders, to get some kind of incentive and the fear of loosing believers by cooperation with other organisations. A higher degree of transparency in this issue would probably solve some irritations and tensions.As for the sustainability of the literacy skills much may be done to improve. The acquired skills seem to be comparably relevant. The level achieved, and the level tested, may be defined as basic literacy skills, consisting of basic reading, writing and numeracy skills. However, these skills are very restricted and there is a high risk that the skills will decline, which means that there is a high risk that people will forget how to read and write because of lack of exercising. From these conclusions a few suggestions for future development will be given.

Pretty good for a girl: gender, identity and computer games

Young people’s participation in online digital culture is one of the most efficient means by which they become proficient in the management of Information and Communications Technologies and the new literacies emerging there. This paper reports on a small project investigating the
gendered dimensions of teenagers’ engagement in and out of school with stand-alone and multiplayer computer games. The study explored the game playing practices of a group of students in an English curriculum unit and the social and game playing practices of a group of young women of South East Asian backgrounds in a LAN café who had formed their own Counterstrike clan. It found that expertise is not just a matter of specific skills, strategies and familiarity, but is more broadly located within the complex dynamics of in- and out-of-school discourses and contexts that need to be factored in to the construction of gender-equitable pedagogy and curriculum.

Induction of epithelial to mesenchymal transition in PMC42-LA human breast carcinoma cells by carcinoma-associated fibroblast secreted factors

Background
Breast carcinoma is accompanied by changes in the acellular and cellular components of the microenvironment, the latter typified by a switch from fibroblasts to myofibroblasts.


Methods
We utilised conditioned media cultures, Western blot analysis and immunocytochemistry to investigate the differential effects of normal mammary fibroblasts (NMFs) and mammary cancer-associated fibroblasts (CAFs) on the phenotype and behaviour of PMC42-LA breast cancer cells. NMFs were obtained from a mammary gland at reduction mammoplasty, and CAFs from a mammary carcinoma after resection.


Results
We found greater expression of myofibroblastic markers in CAFs than in NMFs. Medium from both CAFs and NMFs induced novel expression of α-smooth muscle actin and cytokeratin-14 in PMC42-LA organoids. However, although conditioned media from NMFs resulted in distribution of vimentin-positive cells to the periphery of PMC42-LA organoids, this was not seen with CAF-conditioned medium. Upregulation of vimentin was accompanied by a mis-localization of E-cadherin, suggesting a loss of adhesive function. This was confirmed by visualizing the change in active β-catenin, localized to the cell junctions in control cells/cells in NMF-conditioned medium, to inactive β-catenin, localized to nuclei and cytoplasm in cells in CAF-conditioned medium.


Conclusion
We found no significant difference between the influences of NMFs and CAFs on PMC42-LA cell proliferation, viability, or apoptosis; significantly, we demonstrated a role for CAFs, but not for NMFs, in increasing the migratory ability of PMC42-LA cells. By concentrating NMF-conditioned media, we demonstrated the presence of factor(s) that induce epithelial-mesenchymal transition in NMF-conditioned media that are present at higher levels in CAF-conditioned media. Our in vitro results are consistent with observations in vivo showing that alterations in stroma influence the phenotype and behaviour of surrounding cells and provide evidence for a role for CAFs in stimulating cancer progression via an epithelial-mesenchymal transition. These findings have implications for our understanding of the roles of signalling between epithelial and stromal cells in the development and progression of mammary carcinoma.

LAN cafes: cafes, places of gathering or sites of informal teaching and learning?

Despite the interest of sociologists and educational researchers in Internet café as sites for new cultural and social formations and informal learning, thus far little attention has been paid to the function of café owners, managers and other staff in the mediation and co-construction of those spaces. Drawing from interviews with managers of commercial Internet café in Australia specialising in LAN (Local Area Network) gaming, this article seeks to examine their role and their attitudes more closely; in particular with regard to school-aged users of their facilities. We contend that LAN café are liminal spaces situated at the margins of Australian culture and located at the junctions between home, school and the street, online and offline spaces, work and play. The roles of LAN café managers are similarly ambiguous: in many ways they can be regarded as informal teachers facilitating the process of informal learning.

Children's fruit and vegetable intake : Associations with the neighbourhood food environment

Objective : To examine associations between availability of different types of food outlets and children's fruit and vegetable intake.
Method : Parents of 340 5–6 and 461 10–12 year-old Australian children reported how frequently their child ate 14 fruits and 13 vegetables in the last week in 2002/3. A geographic information system (GIS) was used to determine the availability of the following types of food outlets near home: greengrocers; supermarkets; convenience stores; fast food outlets; restaurants, cafés and takeaway outlets. Logistic regression analyses examined the likelihood of consuming fruit ≥ 2 times/day and vegetables ≥ 3 times/day, according to access to food outlets.
Results : Overall, 62.5% of children ate fruit ≥ 2 times/day and 46.4% ate vegetables ≥ 3 times/day. The more fast food outlets (OR = 0.82, 95%CI = 0.67–0.99) and convenience stores (OR = 0.84, 95%CI = 0.73–0.98) close to home, the lower the likelihood of consuming fruit ≥ 2 times/day. There was also an inverse association between density of convenience stores and the likelihood of consuming vegetables ≥ 3 times/day (OR = 0.84, 95%CI = 0.74–0.95). The likelihood of consuming vegetables ≥ 3 times/day was greater the farther children lived from a supermarket (OR = 1.27, 95%CI = 1.07–1.51) or a fast food outlet (OR = 1.19, 95%CI = 1.06–1.35).
Conclusion : Availability of fast food outlets and convenience stores close to home may have a negative effect on children's fruit and vegetable intake.

Family food environments as determinants of children's eating : implications for obesity prevention

The prevalence of childhood obesity is escalating rapidly and it considered to be a major public health problem. Diet is a recognised precursor of fatness, and current evidence supports the premise that in Westernised countries, the dietary intakes of children are likely to be important in obesity genesis. However, we have a relatively poor understanding of the environments in which a child’s eating is learnt and maintained. Much of the existing work in this area is based on small-scale or experimental studies, or has been derived from homogeneous populations within the USA. Despite these limitations, there is evidence that aspects of the child’s family environment are likely to be important in determining obesity risk in children. This thesis examines the impact of the family food environment on a child’s eating through two related studies. The first study, titled the Children and Family Eating (CAFÉ) study comprised three phases. Phase one involved qualitative interviews with 17 parents of 5-6 year-old children to explore parental perceptions regarding those factors in a child’s environment believed to influence the development of their child’s eating habits. These interviews were used to inform the development of quantitative measures of the family food environment. The second phase involved the development of a Food Frequency Questionnaire (FFQ) to assess dietary intake in 5-6 year-olds. The FFQ was informed by analysis of 1995 Australian National Nutrition Survey data. In the final phase the relationships between dietary intakes of 5-6 year-old children, and potential predictors of dietary intake were examined in a cross-sectional study of 560 families. Predictors included measures of: parental perceptions of the adequacy of their child’s diet; food availability and accessibility; child-feeding; the opportunities for parental modelling of food intake; a child’s television exposure; maternal Body Mass Index; and maternal education. Analysis of the CAFÉ data provides unique information regarding the relationships between a child’s family food environment and their food consumption. Models developed for a range of dietary outcomes considered to be predictive of increased risk for obesity, including total energy and fat intakes, vegetable variety, vegetable consumption, and high-energy (non-dairy) fluid consumption, explained between 11 and 20 percent of the variance in dietary intake. Two aspects of the family food environment, parental perception of a child’s dietary adequacy, and the total minutes of television viewed per day, were frequently found to be predictive of dietary outcomes likely to promote fatness in these children. The second study, titled the Parent Education and Support (PEAS) Feeding Intervention Study, was a prospective pre/post non-randomised intervention trial that assessed the impact of a feeding intervention to 240 first-time mothers of one-year-old children. This intervention focused on one aspect of the family food environment, child-feeding, which has been proposed as influential in the development of obesogenic eating behaviours. In this study, Maternal and Child Health Nurses (MCHNs), using a ‘Division of Responsibility’ model of feeding, taught parents to provide nutritious food at regular intervals and to let children decide if to eat and how much to eat. Thus parents were encourages to food their child without exerting pressure, or employing coercion or rewards (controlling behaviours). The aim was to influence parental attitudes and beliefs regarding child-feeding. Through the use of these feeding techniques, this intervention also aimed to increase the variety of fruits and vegetables a child consumed by teaching parents to persist with offering these foods, over the year of the intervention, in non-emotive environments. Fruits and vegetables were chosen in this intervention because they are likely to be protective in the development of obesity. Analysis of the PEAS data suggests that this low-level feeding intervention, delivered through existing Maternal and Child Health services, was modestly effective in changing parental attitudes and beliefs regarding the feeding of young children. Further, the validity of fruits offered to intervention group children increased. This thesis expands the existing knowledge base by providing a comprehensive analysis of the relative impact of aspects of the family environment on dietary intakes of 5-6 year-olds. Further, the analysis of a feeding intervention in first-time parents provides important insights regarding the potential to influence child-feeding and the impact this may have on the promotion of eating behaviours protective against obesity.

The assessment of тт-тт selective stationary phases for two-dimensional HPLC analysis of foods : application to the analysis of coffee

Differences between alkyl, dipole–dipole, hydrogen bonding, and π-π selective surfaces represented by non-resonance and resonance π-stationary phases have been assessed for the separation of ‘Ristretto’ café espresso by employing 2DHPLC techniques with C18 phase selectivity detection. Geometric approach to factor analysis (GAFA) was used to measure the detected peaks (N), spreading angle (β), correlation, practical peak capacity (n_p) and percentage usage of the separations space, as an assessment of selectivity differences between regional quadrants of the two-dimensional separation plane. Although all tested systems were correlated to some degree to the C18 dimension, regional measurement of separation divergence revealed that performance of specific systems was better for certain sample components. The results illustrate that because of the complexity of the ‘real’ sample obtaining a truly orthogonal two-dimensional system for complex samples of natural origin may be practically impossible.