Hidden Markov Models With Set-Valued Parameters

Hidden Markov models (HMMs) are widely used probabilistic models of sequential data. As with other probabilistic models, they require the specification of local conditional probability distributions, whose assessment can be too difficult and error-prone, especially when data are scarce or costly to acquire. The imprecise HMM (iHMM) generalizes HMMs by allowing the quantification to be done by sets of, instead of single, probability distributions. iHMMs have the ability to suspend judgment when there is not enough statistical evidence, and can serve as a sensitivity analysis tool for standard non-stationary HMMs. In this paper, we consider iHMMs under the strong independence interpretation, for which we develop efficient inference algorithms to address standard HMM usage such as the computation of likelihoods and most probable explanations, as well as performing filtering and predictive inference. Experiments with real data show that iHMMs produce more reliable inferences without compromising the computational efficiency.

Test-retest variability in structural and functional parameters of glaucoma damage in the glaucoma imaging longitudinal study.

PURPOSE:

To determine the test-retest variability in perimetric, optic disc, and macular thickness parameters in a cohort of treated patients with established glaucoma.

PATIENTS AND METHODS:

In this cohort study, the authors analyzed the imaging studies and visual field tests at the baseline and 6-month visits of 162 eyes of 162 participant in the Glaucoma Imaging Longitudinal Study (GILS). They assessed the difference, expressed as the standard error of measurement, of Humphrey field analyzer II (HFA) Swedish Interactive Threshold Algorithm fast, Heidelberg retinal tomograph (HRT) II, and retinal thickness analyzer (RTA) parameters between the two visits and assumed that this difference was due to measurement variability, not pathologic change. A statistically significant change was defined as twice the standard error of measurement.

RESULTS:

In this cohort of treated glaucoma patients, it was found that statistically significant changes were 3.2 dB for mean deviation (MD), 2.2 for pattern standard deviation (PSD), 0.12 for cup shape measure, 0.26 mm for rim area, and 32.8 microm and 31.8 microm for superior and inferior macular thickness, respectively. On the basis of these values, it was estimated that the number of potential progression events detectable in this cohort by the parameters of MD, PSD, cup shape measure, rim area, superior macular thickness, and inferior macular thickness was 7.5, 6.0, 2.3, 5.7, 3.1, and 3.4, respectively.

CONCLUSIONS:

The variability of the measurements of MD, PSD, and rim area, relative to the range of possible values, is less than the variability of cup shape measure or macular thickness measurements. Therefore, the former measurements may be more useful global measurements for assessing progressive glaucoma damage.

Influence of corneal structure, corneal responsiveness, and other ocular parameters on tonometric measurement of intraocular pressure.

PURPOSE: To estimate the relationships between ocular parameters and tonometrically measured intraocular pressure (IOP), to determine the influence of ocular parameters on different instrument measurements of IOP, and to evaluate the association of ocular parameters with a parameter called hysteresis. METHODS: Patients presenting at a glaucoma clinic were recruited for this study. Subjects underwent IOP measurement with the Goldmann applanation tonometer (GAT), the TonoPen, and the Reichert Ocular Response Analyzer (ORA), and also measurements of central corneal thickness (CCT), axial length, corneal curvature, corneal astigmatism, central visual acuity, and refractive error. Chart information was reviewed to determine glaucoma treatment history. The ORA instrument provided a measurement called corneal hysteresis. The association between measured IOP and the other ocular characteristics was estimated using generalized estimating equations. RESULTS: Among 230 patients, IOP measurements from the TonoPen read lowest, and ORA read highest, and GAT measurements were closest to the mean IOP of the 3 instruments. In a multiple regression model adjusting for age, sex, race, and other ocular characteristics, a 10 microm increase in CCT was associated with an increase of 0.79 mm Hg measured IOP in untreated eyes (P<0.0001). Of the 3 tonometers, GAT was the least affected by CCT (0.66 mm Hg/10 mum, P<0.0001). Hysteresis was significantly correlated with CCT with a modest correlation coefficient (r=0.20, P<0.0007). CONCLUSIONS: Among parameters related to measured IOP, features in addition to CCT, such as hysteresis and corneal curvature, may also be important. Tonometric instruments seem to be affected differently by various physiologic characteristics.

Evaluation of Restorative Dentistry Specialty Registrars’ Clinical Experience of Developmental Disorders: A Survey

Background

Specialty Registrars in Restorative Dentistry (StRs) should be competent in the independent restorative management of patients with developmental disorders including hypodontia and cleft lip/palate upon completion of their specialist training.1 Knowledge and management may be assessed via the Intercollegiate Specialty Fellowship Examination (ISFE) in Restorative Dentistry.2

Objective

The aim of this study was to collate and compare data on the training and experience of StRs in the management of patients with developmental disorders across different training units within the British Isles.

Methods

Questionnaires were distributed to all StRs attending the Annual General Meeting of the Specialty Registrars in Restorative Dentistry Group, Belfast, in October 2015. Participants were asked to rate their confidence and experience of assessing and planning treatment for patients with developmental disorders, construction of appropriate prostheses, and provision of dental implants. Respondents were also asked to record clinical supervision and didactic teaching at their unit, and to rate their confidence of passing a future ISFE station assessing knowledge of developmental disorders.

Results

Responses were obtained from 32 StRs (n=32) training within all five countries of the British Isles. The majority of respondents were based in England (72%) with three in Wales, and two in each of Scotland, Northern Ireland, and the Republic of Ireland. Approximately one third of respondents (34%) were in the final years of training (years 4-6). Almost half of the StRs reported that they were not confident of independently assessing (44%) new patients with a developmental disorder, with larger numbers (72%) indicating a lack of confidence in treatment planning. Six respondents rated their experience of treating obturator patients as ‘poor’ or ‘very poor’. The majority (56%) rated their experience of implant provision in these cases as ‘good’ or ‘excellent’ with three-quarters (75%) rating clinical supervision at their unit as ‘good’ or ‘excellent’. Less than half (41%) rated the didactic teaching at their unit as ‘good’ or ‘excellent’, and only 8 StRs indicated that they were confident of passing an ISFE station focused on developmental disorders.

Conclusion

Experience and training regarding patients with developmental disorders is inconsistent for StRs across the British Isles with a number of trainees reporting a lack of clinical exposure.

POPULATION DYNAMICS OF PLANT PARASITIC NEMATODES AND THEIR RELATIONSHIPS WITH SOIL PHYSICO-CHEMICAL PARAMETERS DURING THE FALLOW PERIOD AFTER SUGARBEET AND LEADING INTO TOMATO CULTIVATION

The main objective of this research was the study of the soil nematode community, and in particular plant parasitic nematodes (PPN), from a field located in Portugal’s southern region, used for sugarbeet production. The study was performed from February to July 2003, covering part of the fallow period previous to tomato cultivation, the alternative crop in the rotation. The end of the fallow period in March and the soil preparation period in May were marked by a significant reduction in the numbers of PPN, whereas their numbers increased on the following tomato crop. The genus Helicotylenchus stood out as the most representative group, forming 90% of all PPN counted each month. The genus Heterodera was relatively abundant in the months following the previous sugarbeet crop, and numbers of the genus Meloidogyne increased during the tomato crop. The correlations between these group and environmental parameters show that, apart from the direct influence of the host, pH, organic matter, temperature and soil moisture significantly influenced nematode abundance and community composition.

Developmental biology and cytogenetics of B. xylophilus

The pine wood nematode Bursaphelenchus xylophilus reproduces bisexually: a haploid sperm fertilizes a haploid oocyte, and the two pronuclei rearrange, move together, fuse, and begin diploid development. Early embryonic events taking place in the B. xylophilus embryo are similar to those of Caenorhabditis elegans, although the anterior-posterior axis appeares to be determined oppositely to that observed for C. elegans. Thai is, in the B. xylophilus embryo, the male pronucleus emerges at the future anterior end, whereas the female pronucleus appeares laterally. To understand the evolution of nematode developmental systems, we cloned the full length of Bx-tbb-1 (beta tubulin) from B. xylophilus cDNA and attempted to apply reverse genetics analysis to B. xylophilus. Several lengths of double stranded RNA (dsRNA) for the Bx-tbb-1 gene were synthesized by in vitro transcription, and both B. xylophilus and C. elegans were soaked in dsRNA for RNAi. Both nematodes could suck up the dsRNA, and we could detect the abnormal phenotypes caused by Bx-tbb-1 dsRNA in C. elegans, but not in B. xylophilus. We suspect that systemic RNAi might be suppressed in B. xylophilus and are attempting to establish other methods for functionally analyzing B. xylophilus genes.

EFFECT OF DIFFERENT STORAGE CONDITIONS ON NUTRITIONAL AND QUALITY PARAMETERS OF 'SWEETHEART' CHERRY.

Abstract The sweet cherry ‘Sweetheart’, although having a short shelf life, is highly appreciated by consumers due to its organoleptic characteristics. Different storage methods were tested to study the maintenance of quality during a period of 27 days: 1) cold (air at 1°C and 95% relative humidity) (CC), 2) cold and polypropylene film bags (1°C and 95% relative humidity) (MA) and 3) cold and controlled atmosphere (1°C, 95% RH, 10% CO2 and 8% O2) (CA). Quality parameters tested included external colour (L*, a*, b*), total soluble solids (TSS), and titratable acidity (TA). To evaluate nutritional quality anthocyanins, total antioxidant activity, and total phenolics were measured. Results allow us to say that phenolic compounds were relatively stable and similar during storage in CC and MA. Cherries stored under CA conditions presented lowest concentrations of phenolic compounds. Phenolic compounds, total anthocyanins and antioxidant activity were inversely correlated with values of colour coordinates. Considering all the evaluations done during this work it is unquestionable that fruits stored in controlled atmosphere conditions had significantly different quality.

Evaluation of different postharvest conditions to preserve the amount of bioactive compounds, physicochemical quality parameters and sensory attributes of ‘Sweetheart’ cherries.

Sweet cherries (Prunus avium L.) ‘Sweetheart’ were harvested at different production regions from Portugal (Cova da Beira and Portalegre) and Spain (Valle de Jerte). Cherries were harvested at their commercial maturation according to the empirical knowledge of external color corresponding to good quality. Fruits were stored and evaluated in order to study their quality on the harvest day and during a period of 21 days, at cold storage (1 ºC, 95% RH). The sweet cherry ‘Sweetheart’ is a well-known variety and a highly appreciated one but fruits present a short shelf life. On the other hand the effect of different “terroir” on cherry characteristics should be known and clarified. Fruits from day 0, considered without storage, were kept at 20ºC and analyzed. Every weak, 3 replicas were randomly picked up and 10 fruits from each one were submitted to several analyses after fruit temperature stabilized at 20ºC. Several quality parameters were evaluated: external colour (L*, a*, b*), texture, soluble solids content (SSC), titratable acidity (TA) and the ratio between soluble solid contents (SSC) and tritratable acidity (TA). Fruits from different orchards and locations were significantly different according to these parameters. Fruits from Cova da Beira were less firm comparing with other two regions, Valle de Jerte and Portalegre, which may indicate a higher maturation rate at harvest in those fruits. This is in accordance with SSC/titratable acidity rate suggesting a late harvest in Cova da Beira comparing with other two orchards, however fruits from Cova da Beira exhibit a poor color at harvest. These results clearly showed a lower correlation between SSC and firmness considering fruits origin.

SHORT-TERM EFFECTS OF SALINITY ON SOME PHYSIOLOGICAL PARAMETERS OF YOUNG OLIVE TREES OF ARBEQUINA, COBRANÇOSA AND GALEGA VARIETIES

SHORT-TERM EFFECTS OF SALINITY ON SOME PHYSIOLOGICAL PARAMETERS OF YOUNG OLIVE TREES OF ARBEQUINA, COBRANÇOSA AND GALEGA VARIETIES Ana Elisa Rato1,4, Renato Coelho1, Margarida Vaz1, Teresa Carola2, Dália Barbosa2, Nádia Silva1, José dos Santos2, Lourenço Machado2, João Godinho2, Luzia Ruas2, Margarida Barradas2, Hernani Pereira2, Sara Porfírio4 1 ICAAM, Universidade de Évora, Apartado 94, 7002-554 Évora, Portugal 2 Master students, Universidade de Évora, Apartado 94, 7002-554 Évora, Portugal 3 Ph.D. student, Universidade de Évora, Apartado 94, 7002-554 Évora, Portugal 4 aerato@uevora.pt Due to the desertification in some regions, the interest in plant’s tolerance to salinity has been increasing, as this response is determining for plant survival in stress conditions. This work reports the investigation of tolerance to salt in two year-old olive trees (Olea europaea L.) of three varieties, Arbequina, Cobrançosa and Galega vulgar. Plants were grown in 10 L plastic pots containing approximately 9 Kg of a sandy granitic soil, on a greenhouse. For 3 months (from the beginning of February to the end of April 2012), they were subjected to three levels of salinity in the irrigation water, 0 mM, 80 mM and 200 mM NaCl (6 plants per salinity level in a total of 18 plants of each variety),. Stomatal conductance (gs) and relative leaf chlorophyll content were assessed on each plant in February, March and April. Mid-day leaf water potential () and soil salinity were measured at the end of the experiment (April). On average, concerning all treatments and dates of determination, stomatal conductance of Arbequina and Galega vulgar was quite similar, around 40 mmol m-2 s-1, but Cobrançosa had a value of gs 36% higher, almost 50% higher (61 mmol m-2 s-1) when compared with the controls (0 mM salt) of the other two varieties. In percentage of controls, there was little difference in gs between varieties and between salinities during February and March. In contrast, in April, after about 90 days of exposure to salt, there was a clear decrease in gs with salt irrigation, proportional to salt concentration. Compared with controls, plants irrigated with 200 mM salt showed around 80% (Arbequina) or 85% (Cobrançosa and Galega vulgar) decrease in gs. Chlorophyll content of leaves showed less than 5% difference between varieties on the average of all treatments and dates of determination. During the course of this experiment, the salinity levels used did not show any relevant effect on chlorophyll content. Overall, at the end of the experimental period (April), leaf water potential () at midday was significantly higher in Cobrançosa (-1,4 MPa) than in Galega vulgar (-1,7 MPa) or Arbequina (-1,8 MPa), and salt decreased  of control plants (-1,25 MPa) by an average 30% (with 80 mM) and 65% (with 200 mM). At the end of the experiment, salinity in the soil irrigated with 0 mM, 80 mM or 200 mM NaCl was, on average of all varieties, 0,2 mS, 1,0 mS or 2,0 mS, respectively. Soil salinity was quite similar in Arbequina and Galega vulgar but about 35% lower in the pots of Cobrançosa, on average of all salt-irrigation levels. Plants of Cobrançosa had higher stomatal conductance, however they showed higher water potential and lower salinity in the soil. These apparently contradictory results seem to suggest that Cobrançosa responds to salt differently from the other two varieties. This issue needs further investigation.

Pre- and post-settlement processes regulating recruitment of the shore crab Carcinus maenas

O sucesso do recrutamento em espécies com ciclos de vida complexos, i.e. com duas ou mais fases de desenvolvimento, depende do fornecimento de larvas aos locais apropriados do assentamento (mecanismos de pré-assentamento) e na consequente sobrevivência destas larvas até aos estágios bentónicos iniciais (mecanismos de pós-assentamento). O estudo dos principais processos físicos que controlam a variabilidade intra-anual do recrutamento do caranguejo Carcinus maenas foi possível com à obtenção em séries diárias da abundância de megalopas no plâncton e do seu assentamento em substratos artificiais de assentamento, e de parâmetros físicos relacionados com a amplitude de maré e o upwelling, durante os meses da época reprodutiva deste caranguejo. Os nossos resultados demonstraram um padrão cíclico de fornecimento de megalopas de C. maenas aos estuários na costa ocidental de Portugal, relacionado com a amplitude de maré e favorecido pelos ventos de sul. O assentamento de megalopas nos substratos artificiais de assentamento mostrou-se desacoplado do fornecimento nos dois estuários. Os dados obtidos sugerem que as megalopas são transportadas para a costa após a acção de ventos de downwelling, e o fornecimento para os estuários ocorre por transporte selectivo por corrente de maré. A utilização de substratos artificiais para medir densidades de juvenis de Carcinus maenas deve ser ponderada, uma vez que se verificou que em habitats estruturalmente menos complexos os juvenis utilizam os colectores como refúgio; em habitats mais complexos, os juvenis preferiram refugiar-se nas ervas marinhas existentes. No entanto, a estimativa de abundâncias diárias medidas nos colectores permitiu a descrição das abundâncias dos vários estádios de desenvolvimento juvenis, bem como as respectivas taxas de crescimento. As capacidades locomotoras de diferentes classes de tamanho de juvenis de C. maenas foram estimadas mediante o cálculo de um índice de locomoção. Os nossos resultados sugerem que os juvenis mais pequenos estão relativamente protegidos em habitats com vegetação densa, provavelmente porque este tipo de habitats inibe os movimentos dos juvenis de maiores dimensões. Foram também encontradas evidências da existência de segregação temporal na actividade locomotora das diferentes classes de juvenis, que funcionará como um mecanismo que permite reduzir o canibalismo e, consequentemente, aumentar a capacidade de suporte dos habitats juvenis. Foi realizado um estudo sobre o canibalismo nos juvenis de C. maenas na Ria de Aveiro, in situ e utilizando densidades reais. Verificou-se que as presas mais pequenas eram as mais vulneráveis, sendo os juvenis de maiores dimensões os predadores mais eficazes. Por outro lado, as taxas de canibalismo foram menores em habitats com elevadas densidades de refúgio (Zostera noltii). A estimativa das taxas diárias de mortalidade devidas ao canibalismo são aproximadamente metade das taxas diárias de mortalidade devidas aos processos de pré-assentamento, indicando que esta população de C. maenas será regulada pelo fornecimento larvar, i.e., será uma população regulada essencialmente por mecanismos préassentamento.

Endocrine disruption in the terrestrial isopod porcellio scaber

Nas últimas décadas tem-se assistido a uma preocupação crescente relativamente às possíveis consequências da exposição a compostosxenóbioticos capazes de modular ou causar disrupção do sistema endócrino, os denominados Compostos Disruptores Endócrinos (CDEs). A maioria dos estudos efectuados tem-se centrado principalmente nos efeitos dos CDEs em vertebrados, enquanto que os seus efeitos em invertebrados têmsido negligenciados, embora este grupo represente mais de 95% de todas asespécies animais. Isópodes como o Porcellio scaber, combinam características associadas às mudas e aos processos reprodutivos mediados por mecanismos endócrinosconhecidos com um modo de vida terrestre, tornando-os potenciais espécies sentinela para estudos de disrupção endócrina (DE) em ambientes terrestres. Neste estudo, isópodes machos adultos, machos e fêmeas juvenis e casais foram expostos a concentrações crescentes dedois CDEs, vinclozolina (Vz) e bisfenol A (BPA). Testou-se a hipótese nula que a Vz e o BPA não interferem com o desenvolvimento e reprodução deste isópode terrestre. Foi investigadaa possível ligação entre os efeitos causados pelos compostos propostos e DE assim como a ligação a outros potenciais mecanismos de toxicidade.Parâmetros como concentração de 20-hidroxiecdisona (20E), muda, crescimento, rácios sexuais ediversos parâmetros reprodutivos foram estudados. Adicionalmente, de modo a estudar os alvos moleculares destes tóxicos, analisou-se a expressão proteica do intestino, hepatopâncreas e testículos do isópode após exposição aos químicos. Os resultados demonstram que a Vz e o BPA estimulam o aumento dos níveis de 20E de um modo dependente da dose. Excepção feita para a concentração mais baixa de BPA testada (10 mg/kg solo), para a qual concentrações significativamente mais altas de 20E foram determinadas, sugerindo a ocorrência dos “efeitos de baixas doses típicos de DE” já demonstrados por outros autores. O BPA também distorceu o rácio sexual favorecendo asfêmeas na concentração mais baixa. A mortalidade devido à ecdise incompleta foi relacionada com o hiper-ecdisonismo nas concentrações mais elevadas de Vz. Mais ainda, a Vz tende a atrasar a muda e o BPA a induzi-la. Não obstante, ambos os compostos provocam toxicidade no desenvolvimento,uma vez que foi encontrada uma diminuição generalizada nos parâmetros de crescimento. Os juvenis mostraram ser mais sensíveis à exposição aos tóxicos que os adultos. Estes compostos provocaram ainda toxicidade reprodutiva, com um decréscimo generalizado do “output” reprodutivo. A toxicidadecausada pelos ecdisteróides e o seu papel na síntese de vitelogenina são alguns dos factores chave que poderão influenciar negativamente a reprodução.A Vz e o BPA afectaram a expressão de proteínas envolvidas nometabolismo energético e induziram várias respostas de stress. Interferiram ainda com proteínas intimamente ligadas com o sucesso reprodutivo. Conclui-se assim,que ambos os CDEs propostos provocam toxicidade nodesenvolvimento e na reprodução de P. scaber, tendo sido evidenciada umaligação a DE. Alvos moleculares de natureza não-endócrina foram também revelados, através da expressão diferencial de algumas proteínaspreviamente descritas para invertebrados aquáticos e mesmo alguns vertebrados.

Radiological imaging in digital systems: the effect of exposure parameters in diagnostic quality and patient dose

Esta tese pretende contribuir para o estudo e análise dos factores relacionados com as técnicas de aquisição de imagens radiológicas digitais, a qualidade diagnóstica e a gestão da dose de radiação em sistema de radiologia digital. A metodologia encontra-se organizada em duas componentes. A componente observacional, baseada num desenho do estudo de natureza retrospectiva e transversal. Os dados recolhidos a partir de sistemas CR e DR permitiram a avaliação dos parâmetros técnicos de exposição utilizados em radiologia digital, a avaliação da dose absorvida e o índice de exposição no detector. No contexto desta classificação metodológica (retrospectiva e transversal), também foi possível desenvolver estudos da qualidade diagnóstica em sistemas digitais: estudos de observadores a partir de imagens arquivadas no sistema PACS. A componente experimental da tese baseou-se na realização de experiências em fantomas para avaliar a relação entre dose e qualidade de imagem. As experiências efectuadas permitiram caracterizar as propriedades físicas dos sistemas de radiologia digital, através da manipulação das variáveis relacionadas com os parâmetros de exposição e a avaliação da influência destas na dose e na qualidade da imagem. Utilizando um fantoma contrastedetalhe, fantomas antropomórficos e um fantoma de osso animal, foi possível objectivar medidas de quantificação da qualidade diagnóstica e medidas de detectabilidade de objectos. Da investigação efectuada, foi possível salientar algumas conclusões. As medidas quantitativas referentes à performance dos detectores são a base do processo de optimização, permitindo a medição e a determinação dos parâmetros físicos dos sistemas de radiologia digital. Os parâmetros de exposição utilizados na prática clínica mostram que a prática não está em conformidade com o referencial Europeu. Verifica-se a necessidade de avaliar, melhorar e implementar um padrão de referência para o processo de optimização, através de novos referenciais de boa prática ajustados aos sistemas digitais. Os parâmetros de exposição influenciam a dose no paciente, mas a percepção da qualidade de imagem digital não parece afectada com a variação da exposição. Os estudos que se realizaram envolvendo tanto imagens de fantomas como imagens de pacientes mostram que a sobreexposição é um risco potencial em radiologia digital. A avaliação da qualidade diagnóstica das imagens mostrou que com a variação da exposição não se observou degradação substancial da qualidade das imagens quando a redução de dose é efectuada. Propõe-se o estudo e a implementação de novos níveis de referência de diagnóstico ajustados aos sistemas de radiologia digital. Como contributo da tese, é proposto um modelo (STDI) para a optimização de sistemas de radiologia digital.

Channel estimation and parameters acquisition systems employing cooperative diversity

This work investigates new channel estimation schemes for the forthcoming and future generation of cellular systems for which cooperative techniques are regarded. The studied cooperative systems are designed to re-transmit the received information to the user terminal via the relay nodes, in order to make use of benefits such as high throughput, fairness in access and extra coverage. The cooperative scenarios rely on OFDM-based systems employing classical and pilot-based channel estimators, which were originally designed to pointto-point links. The analytical studies consider two relaying protocols, namely, the Amplifyand-Forward and the Equalise-and-Forward, both for the downlink case. The relaying channels statistics show that such channels entail specific characteristics that comply to a proper filter and equalisation designs. Therefore, adjustments in the estimation process are needed in order to obtain the relay channel estimates, refine these initial estimates via iterative processing and obtain others system parameters that are required in the equalisation. The system performance is evaluated considering standardised specifications and the International Telecommunication Union multipath channel models.

Effects of environmental factors on the toxicity of pesticides to zebrafish embryos

During the last century mean global temperatures have been increasing. According to the predictions, the temperature change is expected to exceed 1.5ºC in this century and the warming is likely to continue. Freshwater ecosystems are among the most sensitive mainly due to changes in the hydrologic cycle and consequently changes in several physico-chemical parameters (e.g. pH, dissolved oxygen). Alterations in environmental parameters of freshwater systems are likely to affect distribution, morphology, physiology and richness of a wide range of species leading to important changes in ecosystem biodiversity and function. Moreover, they can also work as co-stressors in environments where organisms have already to cope with chemical contamination (such as pesticides), increasing the environmental risk due to potential interactions. Therefore, the objective of this work was to evaluate the effects of climate change related environmental parameters on the toxicity of pesticides to zebrafish embryos. The following environmental factors were studied: pH (3.0-12.0), dissolved oxygen level (0-8 mg/L) and UV radiation (0-500 mW/m2). The pesticides studied were the carbamate insecticide carbaryl and the benzimidazole fungicide carbendazim. Stressors were firstly tested separately in order to derive concentration- or intensity-response curves to further study the effects of binary combinations (environmental factors x pesticides) by applying mixture models. Characterization of zebrafish embryos response to environmental stress revealed that pH effects were fully established after 24 h of exposure and survival was only affected at pH values below 5 and above 10. Low oxygen levels also affected embryos development at concentrations below 4 mg/L (delay, heart rate decrease and edema), and at concentrations below 0.5 mg/L the survival was drastically reduced. Continuous exposure to UV radiation showed a strong time-dependent impact on embryos survival leading to 100% of mortality after 72 hours of exposure. The toxicity of pesticides carbaryl and carbendazim was characterized at several levels of biological organization including developmental, biochemical and behavioural allowing a mechanistic understanding of the effects and highlighting the usefulness of behavioural responses (locomotion) as a sensitive endpoint in ecotoxicology. Once the individual concentration response relationship of each stressor was established, a combined toxicity study was conducted to evaluate the effects of pH on the toxicity of carbaryl. We have shown that pH can modify the toxicity of the pesticide carbaryl. The conceptual model concentration addition allowed a precise prediction of the toxicity of the jointeffects of acid pH and carbaryl. Nevertheless, for alkaline condition both concepts failed in predicting the effects. Deviations to the model were however easy to explain as high pH values favour the hydrolysis of carbaryl with the consequent formation of the more toxic degradation product 1- naphtol. Although in the present study such explanatory process was easy to establish, for many other combinations the “interactive” nature is not so evident. In the context of the climate change few scenarios predict such increase in the pH of aquatic systems, however this was a first approach focused in the lethal effects only. In a second tier assessment effects at sublethal level would be sought and it is expectable that more subtle pH changes (more realistic in terms of climate changes scenarios) may have an effect at physiological and biochemical levels with possible long term consequences for the population fitness.

Developmental Antecedents of Proactive and Reactive Rebelliousness: The Role of Parenting Style, Childhood Adversity, and Attachment

Adolescence is a time of developmental transition that for one in five young people is characterised by feelings of oppositionality, rebellion, and negativism. Despite the prevalent experience of teen turbulence and despite its significance within the phenomenological framework provided by reversal theory (RT), the childhood antecedents of rebelliousness in adolescence and adulthood have not been given extensive empirical attention within RT, although such work has been carried out using other constructs and theories. We examined recalled parenting style, childhood adversity, and attachment style in adulthood as correlates of proactive and reactive rebelliousness in a sample of 80 participants, aged 18 to 50 years. Each participant responded to a questionnaire package containing the revised Adult Attachment Scale, the Parental Bonding Instrument, the Childhood Experience of Care and Abuse Questionnaire, and the Negativism Dominance Scale. We found that paternal abusive parenting, followed by paternal parenting style, paternal neglect, and paternal antipathy were independently predictive of scores on proactive rebelliousness, the sensation-seeking form. Maternal and paternal indifferent parenting styles each were found to equivalently and independently predict scores on reactive rebelliousness, the interpersonal disaffection form. The results of this study suggest these two forms of rebelliousness may have distinctly different antecedents. A longitudinal study is needed to examine the potentially causal pathways that are suggested by the results of this cross-sectional research. We consider reversal theory explanations of these results and contrast them with complementary theoretical frameworks.