Particle Survival and Polydispersity in Aggregation

We study the probability, $P_S(t)$, of a cluster to remain intact in one-dimensional cluster-cluster aggregation when the cluster diffusion coefficient scales with size as $D(s) \sim s^\gamma$. $P_S(t)$ exhibits a stretched exponential decay for $\gamma < 0$ and the power-laws $t^{-3/2}$ for $\gamma=0$, and $t^{-2/(2-\gamma)}$ for $0<\gamma<2$. A random walk picture explains the discontinuous and non-monotonic behavior of the exponent. The decay of $P_S(t)$ determines the polydispersity exponent, $\tau$, which describes the size distribution for small clusters. Surprisingly, $\tau(\gamma)$ is a constant $\tau = 0$ for $0<\gamma<2$.Comment: submitted to Europhysics Letter

Hoitohenkilökunnan stressinhallinta päivystyshoitotyössä - kirjallisuuskatsaus

Opinnäytetyön tarkoituksena oli kirjallisuuskatsauksen avulla kuvata stressin aiheuttajia, stressin ilmenemistä ja stressin hallintaa päivystyshoitotyössä. Opinnäytetyön tavoitteena oli tuottaa näyttöön perustuvaa tietoa päivystyksessä työskentelevän hoitohenkilökunnan jaksamisen edistämiseksi. Opinnäytetyön tilaaja on Satakunnan keskussairaalan yhteispäivystys. Opinnäytetyössä käytettiin mahdollisimman uutta ja monipuolista aineistoa vuosilta 2005-2016. Alkuperäistutkimuksia haettiin Melinda-, Medic- ja Pubmed-tietokannoista. Hoitohenkilökunnan stressinhallinnasta päivystyshoitotyössä löytyi ainoastaan ulkomaisia tutkimuksia, joten hakua piti laajentaa myös muissa yksiköissä työskentelevien hoitajien stressinhallintaan. Näin opinnäytetyöhön saatiin mukaan myös yksi kotimainen tutkimus. Kirjallisuuskatsaukseen valittiin yhteensä neljä tutkimusta. Stressi on yleinen ihmisen psyykkisesti, fyysisesti ja sosiaalisesti kokema tila, joka voi olla sekä positiivista että negatiivista. Stressi luokitellaan kolmeen pääluokkaan: eustressiin, distressiin ja neustressiin. Haitallinen distressi on se, joka vaikuttaa negatiivisesti ihmisen toimintaan ja työn tuloksiin. Stressin laukaisee työssä usein negatiivisena koetut asiat kuten kiire. Paineen kasautuessa stressi pahenee ja alkaa haitata yksilön ja yhteisön työskentelyä, jolloin stressinhallinnan merkitys korostuu. Tämän kirjallisuuskatsauksen tulosten mukaan stressiä aiheuttivat muun muassa työn liialliset vaatimukset ja kannustavan työympäristön puute. Stressi ilmeni esimerkiksi ristiriitatilanteiden hallinnan puutteena, väsymyksenä ja henkilöstön vaihtuvuutena. Stressin hallintakeinoina hoitohenkilökunta käytti eri selviytymiskeinoja, jotka olivat yhteydessä vähäisempään stressin kokemiseen. Näitä olivat esimerkiksi palautteen vastaanottaminen ja negatiivisten ajatusten välttäminen. Koko työorganisaatio voi vaikuttaa työympäristön stressin kokemiseen antamalla palautetta hyvin tehdystä työstä ja välttämällä hoitotyöntekijöiden kiirettä ja liiallista vastuuta. Lisäksi työvuorojen oikeanlainen suunnittelu vähensi stressin kokemista erityisesti silloin, kun työvuorolista sisälsi mahdollisimman vähän ilta-aamuvuorojen yhdistelmiä.The meaning of thesis was to describe with integrative literature review what is stress management, the occurrence and the causes of stress. The aim of the thesis was to produce evidence-based information to promote nursing staff working in emergency department. The subscriber of this thesis is Satakunta central hospitals emergency department. One of the meanings was to use as new and diverse material as possible in this thesis with publication date between 2005-2016. Primary studies were sought in Melinda-, Medic- and Pubmed-databases. Stress management in emergency nursing found only foreign researches, so the search had to be extended to those nurses and their stress management that are working in other departments. After that, one finnish research was also found to the thesis. 4 different researches is selected into the literature review. Stress is mentally, physically and socially experienced situation, which can be both positive and negative and are classified into a three main categories: eustress, distress and neustress. The most harmful distress is that negatively affect to the daily activities and to the results of the work we do. This thesis and its researches are mostly all about distress. Negative things in the workplace like rush are the most common causes of work stress, and the stress get even worse under pressure and begins to interfere with the work of the individual and the community, so the importance of stress management is emphasized. The results of this literature review shows that the causes of stress are for example lack of supportive work environment and high work demands. Stress occurs when there is lack of conflict management and employees are changing workplaces more than normal or when employee’s are unusually tired. Employee’s use as a stress management different coping mechanism skills that is connected to the perception of a lower levels of stress. These are for example avoiding negative thoughts and receiving feedback. The whole work organization can affect the experience of stress in the working environment by providing feedback on a job that is done well and by avoiding excessive rush and responsibility of nurses. In addition, the right way for planning shifts reduced stress, particularly when the roster included as little as possible evening-morning shift combinations

Ozone stress as a driving force of sesquiterpene emissions: a suggested parameterisation

Sesquiterpenes (C15H24) are semi-volatile organic compounds emitted by vegetation and are of interest in atmospheric research because they influence the oxidative capacity of the atmosphere and contribute to the formation of secondary organic aerosols. However, little is known about their emission pattern and no established parameterisation is available for global emission models. The aim of this study is to investigate a Central European spruce forest and its emission response to meteorological and environmental parameters, looking for a parameterisation that incorporates heat and oxidative stress as the main driving forces of the induced emissions. Therefore, a healthy ca. 80 yr old Norway spruce (Picea abies) tree was selected and a dynamical vegetation enclosure technique was applied from April to November 2011. The emissions clearly responded to temperature changes with small variations in the β-factor along the year (βspring = 0.09 ± 0.01, βsummer = 0.12 ± 0.02, βautumn = 0.11 ± 0.02). However, daily calculated values revealed a vast amount of variability in temperature dependencies ((0.02 ± 0.002) < β < (0.27 ± 0.04)) with no distinct seasonality. By separating the complete dataset in 10 different ozone regimes, we found that in moderately or less polluted atmospheric conditions the main driving force of sesquiterpene emissions is the temperature, but when ambient ozone mixing ratios exceed a critical threshold of (36.6 ± 3.9) ppbv, the emissions become primarily correlated with ozone. Considering the complete dataset, cross correlation analysis resulted in highest correlation with ambient ozone mixing ratios (CCO3 = 0.63 ± 0.01; CCT = 0.47 ± 0.02 at t = 0 h for temperature) with a time shift 2–4 h prior to the emissions. An only temperature dependent algorithm was found to substantially underestimate the induced emissions (20% of the measured; R2 = 0.31). However, the addition of an ozone dependent term improved substantially the fitting between measured and modelled emissions (81% of the modelled emissions could be explained by the measurements; R2 = 0.63), providing confidence about the reliability of the suggested parameterisation for the spruce forest site investigated

Ozone stress as a driving force of sesquiterpene emissions: a suggested parameterization [Discussion paper]

Sesquiterpenes (C15H24) are semi-volatile organic compounds emitted by vegetation and are of interest in atmospheric research because they influence the oxidative capacity of the atmosphere and contribute to the formation of secondary organic aerosols. However, little is known about their emission pattern and no established parameterization is available for global emission models. The aim of this study is to investigate a Central European spruce forest and its emission response to meteorological and environmental parameters, looking for a parameterization that incorporates heat and oxidative stress as the main driving forces of the induced emissions. Therefore, a healthy ca. 80 yr old Norway spruce (Picea abies) tree was selected and a dynamical vegetation enclosure technique was applied from April to November 2011. The emissions clearly responded to temperature changes with small variations in the β-factor along the year (βspring=0.09 ± 0.01, βsummer=0.12 ± 0.02, βautumn=0.11 ± 0.02). However, daily calculated values revealed a vast amount of variability in temperature dependencies ((0.02 ± 0.002)< β<(0.27 ± 0.04)) with no distinct seasonality. By separating the complete dataset in 10 different ozone regimes, we found that in moderately or less polluted atmospheric conditions the main driving force of sesquiterpene emissions is the temperature, but when ambient ozone mixing ratios exceed a~critical threshold of (36.6 ± 3.9) ppbv, the emissions become primarily correlated with ozone. Considering the complete dataset, cross correlation analysis resulted in highest correlation with ambient ozone mixing ratios (CCO3=0.63 ± 0.01; CCT=0.47 ± 0.02 at t=0 h for temperature) with a time shift 2–4 h prior to the emissions. An only temperature dependent algorithm was found to substantially underestimate the induced emissions (20 % of the measured; R2=0.31). However, the addition of an ozone dependent term improved substantially the fitting between measured and modeled emissions (81 % of the measured; R2=0.63), providing confidence about the reliability of the suggested parameterization for the spruce forest site investigated

Cluster persistence in one-dimensional diffusion--limited cluster--cluster aggregation

The persistence probability, $P_C(t)$, of a cluster to remain unaggregated is studied in cluster-cluster aggregation, when the diffusion coefficient of a cluster depends on its size $s$ as $D(s) \sim s^\gamma$. In the mean-field the problem maps to the survival of three annihilating random walkers with time-dependent noise correlations. For $\gamma \ge 0$ the motion of persistent clusters becomes asymptotically irrelevant and the mean-field theory provides a correct description. For $\gamma < 0$ the spatial fluctuations remain relevant and the persistence probability is overestimated by the random walk theory. The decay of persistence determines the small size tail of the cluster size distribution. For $0 < \gamma < 2$ the distribution is flat and, surprisingly, independent of $\gamma$.Comment: 11 pages, 6 figures, RevTeX4, submitted to Phys. Rev.

Design features impacting mobile phone upgrading frequency

This study examines the impact of design on customer upgrading frequency, and differentiates between functional and aesthetic aspects of design. For the empirical study, we conducted an intercept survey in Beijing and Shanghai with Chinese consumers (n=170) in a retail mall setting. The results of the survey show that the functional design aspects of mobile phones (screen size, keyboard, and width of body) affect perceived ease of use, and that design aesthetics (color and thickness of body) moderate the relationship between satisfaction and upgrading frequency. However, we did not gain significant results for the relationship between functional design and perceived usefulness. The results provide initial evidence of the importance of design for consumers when upgrading their mobile phones. The findings highlight the need of further investigating the impact of design. We see, e.g., the potential impact of design on emergent feature fatigue phenomena in mobile phone markets, where consumers begin to desire less functionality from their mobile phones and are willing to replace their advanced phones with simpler models, as a intriguing research avenue

Modeling Physical Accessibility Index for assessing physical accessibility in the City of Helsinki : Case studies from Lauttasaari, Itäkeskus and Keski-Pasila

Kaupunkisuunnittelussa on perinteisesti keskitytty autovirtojen hallintaan, mikä on tehnyt kaupunkialueista pirstaleisia ja jalankulkijoista “kakkosluokan kansalaisia”. Tämä on johtanut kansalaisliikkeiden syntyyn sekä laajoihin protesteihin, joissa varsinkin liikkumis- ja toimimisesteiset henkilöt ovat vaatineet parannuksia rakennetun ympäristön laatuun. Viime vuosikymmenten aikana onkin monissa kaupungeissa ympäri maailmaa aloitettu kehittämään infrastruktuurin laatua. Yksi tällaisista esimerkeistä, jossa kaupunkiympäristön laatua on parannettu ottamaan liikkumis- ja toimimisesteisten henkilöiden tarpeet huomioon, on Helsingin kaupungin Helsinki kaikille –projekti. Tämän tutkimuksen tarkoituksena on luoda paikkatietopohjainen malli kaupunkiympäristön esteettömyyden tason arvioimiseksi. Samalla arvioidaan myös olemassa olevan paikkatietoaineiston käyttökelpoisuus tämänkaltaisen tutkimuksen tekemiseen. Tarkoituksena on myös kriittisesti keskustella sosiaalisen oikeudenmukaisuuden toteutumisesta kaupunkiympäristössä erityisesti liikkumis- ja toimimisesteisten henkilöiden näkökulmasta. Luotu paikkatietopohjainen malli suoritetaan tästä johtuen kolmen eri jalankulkijaryhmän näkökulmasta katsottuna, jotta nähtäisiin, miten nykyinen esteettömyyden taso vaihtelee eri käyttäjäryhmien välillä. Tarkoituksena on myös tutkia sitä, mikä merkitys esteettömyysohjeistuksilla on ollut esteettömyysaspektin tekemisessä luonnolliseksi osaksi suunnitteluprosessia. Helsingin kaupungin rakennetun ympäristön esteettömyyden tasoa tutkitaan tässä tutkimuksessa luomalla esteettömyysindeksi, joka perustuu niin kutsuttuihin kaupunkirakenteen 3D- ja 6D malleihin. Näitä malleja, sekä Helsinki kaikille –projektin määrittelemiä esteettömän rakentamisen kriteerejä, käytetään tutkimuksen teoreettisena viitekehyksenä esteettömyysindeksin luomisessa. Näitä 3D- ja 6D malleja on muokattu huomioimaan esteettömyysaspekti. Lopullinen esteettömyysindeksi muodostuu kahdeksasta ulottuvuudesta, jotka ovat: maankäytön tiiviys, maankäytön monipuolisuus, jalankulkualueen laatu, kohteen saavutettavuus, joukkoliikenteen saavutettavuus, kohdealueen vastaanottavuus, maanpinnan kaltevuus, sekä jalankulkijoiden havainnot. Näitä ulottuvuuksia analysoitaessa on käytetty useita erilaisia menetelmiä. Analyysi on suoritettu kolmen alueen osalta Helsingin kaupungissa: Lauttasaaresta, Itäkeskuksesta sekä Keski-Pasilasta. Tutkimusalueet on valittu sen mukaan, missä alueiden kehityksen vaiheessa esteettömyysaspekti on otettu huomioon. Lauttasaari ja Itäkeskus ovat rakentuneet aikana, jolloin ei vielä ole ollut kattavaa määrää esteettömyysohjeistuksia. Sen sijaan Keski-Pasilassa esteettömyysaspekti on otettu huomioon jo asemakaavaa tehtäessä. Näistä tutkimusalueista Lauttasaaresta ja Itäkeskuksesta on saatavilla rakennettua ympäristöä kuvaavaa paikkatietoaineistoa, jota on hyödynnetty tutkimuksessa. Aineistot on hankittu avoimen datan rajapinnoista sekä suoraan Helsingin kaupungilta. Keski-Pasilan kohdalla aineisto on hankittu suunnitteludokumenteista digitoimalla, sillä alue on tällä hetkellä vasta rakenteilla. Tulokset osoittavat, että Lauttasaaren ja Itäkeskuksen kohdalla tutkimusalueiden keskusta-alueet ovat kehittyneet esteettömyyden kannalta hyvälle tasolle. Tulokset osoittavat myös, että esteettömyyden taso tulee olemaan erittäin hyvä koko Keski-Pasilan tutkimusalueen alueelta, jos alue rakennetaan suunnitelmien mukaisesti. Eri jalankulkijaryhmien välillä on kuitenkin suuria eroja Lauttasaaressa ja Itäkeskuksessa. Keski-Pasilassa ei ollut suuria eroja esteettömyyden tasossa eri jalankulkijaryhmien välillä. Tutkimuksen suorittamisen yhteydessä kävi ilmi, ettei käytetty aineisto ole tarpeeksi tarkkaa tällaisen analyysin tekemiseksi. Helsingin kaupungin ylläpitämään paikkatietoaineistoon suositellaankin siis tehtävän lukuisia päivityksiä ja korjauksia. Tutkimusta varten ei myöskään ollut löydettävissä viitetietoja esteettömyyden kriteerit täyttävistä raja-arvoista kullekin tässä tutkimuksessa analysoidulle ulottuvuudelle. Siksi ehdotetaan, että asiantuntijaraati määrittelisi kullekin ulottuvuudelle soveltuvat esteettömyyden kriteerit täyttävät raja-arvot. Käytetty menetelmä itsessään vaikuttaa kuitenkin tulosten perusteella olevan soveltuva rakennetun ympäristön esteettömyyden arvioimisessa.Traditional city planning has concentrated on auto-mobile flows since the 1930’s making urban areas sprawled and pedestrians as “second citizens”. This has led to widespread popular protests especially from the crowds of persons with impairments residing in cities. However, in recent decades, many cities around the world have shifted their infrastructure development to create better conditions for pedestrians and city life. One of the examples, where the urban environment is enhanced to enable the persons with impairments to fully be integrated in city life, is the Helsinki for all –project in the City of Helsinki. The aim in this research is to create a model for assessing the level of physical accessibility in urban environments. At the same time, the usability of the existing spatial data is evaluated. The aim is also to critically discuss social equality in urban context, and especially from the point of view of the rights of persons with mobility or functionality impairments. Therefore, the model is performed for three different pedestrian user groups to find out, if the level of physical accessibility differs between these groups. The aim is also to research the impact which various physical accessibility criteria have had in making the aspect of physical accessibility a more natural part of the planning process. The created Physical Accessibility Index, by which the current level of physical accessibility is assessed, is derived from the so-called 3D- and 6D models of Urban Structure. These models, and the physical accessibility criteria created by the Helsinki for all –project, are used as a theoretical framework in formulating the model for assessing the level of physical accessibility in the City of Helsinki. The 3D- and 6D models have been modified to take the aspect of physical accessibility into consideration, and the 8D model of physically accessible urban structure has been developed. This model includes the dimensions Density, Diversity, Design, Destination accessibility, Distance to transit, Demand, Declination and Discovery. Various methods have been used when analyzing the 8 dimensions in this 8D model. The analysis is performed for three areas in the City of Helsinki: Lauttasaari, Itäkeskus and Keski-Pasila. The research areas have been chosen to represent areas in which the aspect of physical accessibility has been considered in different phases in the development of these areas. Lauttasaari and Itäkeskus have been built during a time when there was not yet a comprehensive amount of physical accessibility criteria. In Keski-Pasila, on the contrary, the aspect of physical accessibility has been considered already in the local detailed land use plan. Out of these research areas, Lauttasaari and Itäkeskus provide existing spatial data, which has been acquired from open data sources and directly from the City of Helsinki. In the case of Keski-Pasila, which is currently under construction, the required data has been digitized from planning documents. The results show that the centers of the research areas in Lauttasaari and Itäkeskus have been developed and are built well from a physical accessibility point of view. The results show also that Keski-Pasila will in the future have a very good level of physical accessibility in all the new planned areas, if the areas are constructed according to the plans. There are big differences between the different pedestrian user groups in Lauttasaari and in Itäkeskus, but no visible differences between the groups were found in Keski-Pasila. It became clear when performing the analysis that the acquired data was not precise enough for making this kind of analysis. Big updates to the spatial data that the City of Helsinki administrates are therefore needed. Also, criteria for physical accessibility could not be found from literature or previous studies for every dimension, which influenced both the chosen methods and in results. Therefore, an expert group should define thresholds to special and basic level accessibility for each of the dimensions. However, the method itself seems to be suitable in analyzing the level of physical accessibility

Sources and concentrations of volatile organic compounds

Volatile organic compounds (VOCs) have a great influence on tropospheric chemistry; they affect ozone formation and they or their reaction products are able to take part in secondary organic aerosol formation; some of the VOCs are themselves toxic. Knowing the concentrations and sources of different reactive volatile organic compounds is essential for the development of ozone control strategies and for studies of secondary organic aerosol formation. The objective of this work was to study volatile organic compounds in urban air, develop and validate determination methods for them, characterize their concentrations and estimate the contributions of different VOC sources. Of the different compound groups detected in the urban air of Helsinki, alkanes were found to have the highest concentrations, but when the concentrations were scaled against the reactivity with hydroxyl radicals (OH), aromatic hydrocarbons and alkenes were found to have the greatest effect on local chemistry. Comparisons with rural sites showed that concentrations at Utö and Hyytiälä were generally lower than those in Helsinki, especially for the alkenes and aromatic hydrocarbons, but concentrations of halogenated hydrocarbons at Utö and carbonyls at Hyytiälä were at the same level as in Helsinki. Most halogenated hydrocarbons do not have any significant sources in Helsinki, and carbonyls are formed in the atmosphere in the reactions of other VOCs, and are therefore also produced in other than urban areas. At Hyytiälä carbonyls were found to have an important role in the local chemistry. The contribution of carbonyls as an OH sink was higher than that of the monoterpenes and aromatic hydrocarbons. Based on the emission profile and concentration measurements, the contributions of different sources were estimated at urban (Helsinki) and residential (Järvenpää) sites using a chemical mass balance (CMB) receptor model. It was shown that it is possible to apply CMB in the case of a large number of different compounds with different properties. According to the CMB analysis, the major sources for these VOCs in Helsinki were traffic and distant sources. At the residential site in Järvenpää, the contribution due to traffic was minor, while distant sources, liquid gasoline and wood combustion made higher contributions. It was also shown that wood combustion can be an important source at some locations of VOCs usually considered as traffic-related compounds (e.g., benzene).Haihtuviin orgaanisiin yhdisteisiin (VOC) kuulu monentyyppisiä yhdisteitä: alkaaneja, alkeeneja, aromaattisia hiilivetyjä, halogeeneja sisältäviä hiilivetyjä ja hapettuneita yhdisteitä kuten aldehydejä ja ketoneja. Näitä yhdisteitä pääsee ilmaan monenlaisista päästölähteistä. Palaminen, fossiilisten polttoaineiden käyttö, liuottimien käyttö ja teollisuus tuottavat ilmaan suuren joukon VOC yhdisteitä, mutta niitä emittoituu myös luonnosta. Osa VOC yhdisteistä on haitallisia ihmisen terveydelle kuten esim. bentseeni, jonka vuosikeskiarvolle Euroopan Unioni on asettanut pitoisuusrajan. Lähes kaikki VOC yhdisteet reagoivat ilmassa valon vaikutuksesta ja typen oksidien läsnä ollessa saattavat muodostaa otsonia. Ilmassa reagoidessaan orgaaniset yhdisteet muodostavat huonommin haihtuvia yhdisteitä, jotka saattavat osallistua uusien hiukkasten muodostukseen tai kasvuun. Tämän työ tarkoitus oli tutkia kaupunki-ilman haihtuvia orgaanisia yhdisteitä, kehittää määritysmenetelmiä niiden mittaamiseksi ilmasta, määrittää pitoisuustasoja ja arvioida eri VOC lähteiden merkityksiä pitoisuuksiin. Eri yhdisteryhmistä alkaaneilla havaittiin olevan suurimmat pitoisuudet Helsingin ilmassa, mutta jos pitoisuuksia tarkasteltiin reaktiivisuuksien suhteen, aromaattisilla hiilivedyillä ja alkeeneilla havaittiin olevan suurin vaikutus paikalliseen ilmakemiaan. Euroopan Union asettama raja-arvo (5 μg m-3) ilmassa olevan syöpää aiheuttavan bentseenin pitoisuuden vuosikeskiarvolle alittui selkeästi kaikilla mittausasemilla. Eri VOC lähteiden merkitystä arvioitiin erityyppisissä kaupunkiympäristöissä, Helsingissä Kalliossa ja Järvenpäässä pientaloalueella, kemiallisen massatasapaino menetelmän avulla käyttäen lähtötietoina mitattuja päästölähdeprofiileja ja ilmapitoisuuksia. Päälähteet useimmille yhdisteille Helsingissä olivat liikenne ja kaukokulkeuma. Järvenpäässä liikenteen osuus oli pieni verrattuna kaukokulkeuman, bensiinin ja puunpolton osuuksiin. Tutkimuksen avulla pystyttiin toteamaan, että puunpoltto voi olla merkittävä lähde yhdisteille, joiden tavallisesti ajatellaan tulevan pääasiassa liikenteestä (esim. bentseeni)

Cuidar o tratar? : búsqueda del campo de competencia y identidad profesional de la enfermería

Estudo qualitativo cujo objetivo foi identificar o núcleo central das representações sociais sobre os conceitos de cuidar e tratar dos profissionais de enfermagem. Participaram do estudo 45 sujeitos que responderam a um questionário de livre associação. Os dados foram analisados com o auxílio do software Evoc. Os resultados revelam que os conceitos de cuidar e tratar são interpretados como ações opostas e não complementares do ato de cuidar. Essas representações sociais comprometem a definição do campo de prática de enfermagem e sua identidade profissional. Conclui-se que o desafio consiste em aliar o tratamento ao processo de cuidar comprovando que o lugar e as contribuições dos cuidados de enfermagem nas práticas de saúde são insubstituíveis.Qualitative study which purpose was to identify the central nucleus of the social representations about the concepts of taking care and treating under the vision of the nursing professionals. Participated in the study45 subject. The data had been analyzed with the aid of Evoc software. The results reveal that the social representations of the professionals concerning the concepts of taking care and treating point to opposing actions and not complementary in the act of taking care. We conclude that this aspect can compromise the definition of the field of nursing practice and its professional identity. The challenge is in linking the treatment effect that care process and the contributions of the nursing cares in the health practices are irreplaceable.Estudio cualitativo con el objetivo de identificar el núcleo céntrico de las representaciones sociales sobre los conceptos de cuidar y tratar en la visión de los profesionales de enfermería. Participaron del estudio 45 sujetos. Los datos fueron analizados con el auxilio del software Evoc. Los resultados revelan que las representaciones sociales de los profesionales acerca de los conceptos de cuidar y tratar apuntan para acciones opuestas y no complementarias del acto de cuidar. Se concluye que ese aspecto puede comprometer la definición del campo de práctica de enfermería y su identidad profesional. El desafío consiste en demostrar que el lugar y las contribuciones de los cuidados de enfermería en las prácticas de salud son insustituibles

Nonequilibrium dynamics in fiber networks, aggregation, and sand ripples

In nonequilibrium dynamical systems the rich macroscopic behavior arises from simple microscopic processes. While the dominant transport mechanism is often diffusion, there are important dynamics also beyond the diffusive scale. This thesis concentrates on these issues and the effects of spatial fluctuations in various nonequilibrium systems using computer simulations and theoretical arguments. First, the combination of one-dimensional diffusion theory and random walk simulations is demonstrated to be a powerful tool for analyzing gas diffusion through paper-like structures. An efficient simulation method including the effects of fiber sorption is presented. When sorption is present, the characterization of dynamic diffusion processes is not possible using only the usually measured diffusion constant. The deviations between the theory and simulations suggest that the former is invalid for low porosities or thicknesses. Next, the dynamical behavior in aggregation is considered within a one-dimensional model. This model, as in aggregation systems generally, obeys dynamic scaling described by a time-dependent, characteristic length. However, the first-passage quantities involve other scales. A novel mean-field theory is developed to extract the asymptotic time-dependence of unaggregated clusters, which is shown to relate to the small size tail of the cluster size distribution, a quantity of primary importance in aggregation. Then the effect of the presence of two scales on the dynamic scaling properties is discussed by considering the sites staying unvisited by clusters. When an external field like gravitation is applied, the aggregation dynamics is shown to be dominated by the process leading to the fastest growing characteristic length and the dynamic phase diagram is predicted. Finally, coarsening of sand ripples is considered in one-dimensional mass transfer models motivated by sand ripple evolution. When mass is transferred preferably from large ripples to small ones, the ripple size distribution is calculated exactly and is given by a product measure. The approach towards the final state is discussed, leading to a universal decay which depends on the symmetry of the mass transfer. In the case of small clusters vanishing rapidly from the system, the noise in the dynamics is demonstrated to be irrelevant, but the mean-field theory developed fails to account for the numerically observed universality with respect to the initial ripple size distribution.reviewe