Selection, training and validation process of a sensory panel for bread analysis: Influence of cultivar on the quality of breads made from common wheat and spelta wheat

A protocol of selection, training and validation of the members of the panel for bread sensory analysis is proposed to assess the influence of wheat cultivar on the sensory quality of bread. Three cultivars of bread wheat and two cultivars of spelt wheat organically-grown under the same edaphoclimatic conditions were milled and baked using the same milling and baking procedure. Through the use of triangle tests, differences were identified between the five breads. Significant differences were found between the spelt breads and those made with bread wheat for the attributes ?crumb cell homogeneity? and ?crumb elasticity?. Significant differences were also found for the odor and flavor attributes, with the bread made with ?Espelta Navarra? being the most complex, from a sensory point of view. Based on the results of this study, we propose that sensory properties should be considered as breeding criteria for future work on genetic improvement.

User experience with immersive and interactive media = Experiencia de usuario en entornos 3D inmersivos e interactivos

Estudios recientes promueven la integración de estímulos multisensoriales en activos multimedia con el fin de mejorar la experiencia de usuario mediante la estimulación de nuevos sentidos, más allá de la tradicional experiencia audiovisual. Del mismo modo, varios trabajos proponen la introducción de componentes de interacción capaces de complementar con nuevas características, funcionalidades y/o información la experiencia multimedia. Efectos sensoriales basados en el uso de nuevas técnicas de audio, olores, viento, vibraciones y control de la iluminación, han demostrado tener un impacto favorable en la sensación de Presencia, en el disfrute de la experiencia multimedia y en la calidad, relevancia y realismo de la misma percibidos por el usuario. Asimismo, los servicios basados en dos pantallas y la manipulación directa de (elementos en) la escena de video tienen el potencial de mejorar la comprensión, la concentración y la implicación proactiva del usuario en la experiencia multimedia. El deporte se encuentra entre los géneros con mayor potencial para integrar y explotar éstas soluciones tecnológicas. Trabajos previos han demostrado asimismo la viabilidad técnica de integrar éstas tecnologías con los estándares actualmente adoptados a lo largo de toda la cadena de transmisión de televisión. De este modo, los sistemas multimedia enriquecidos con efectos sensoriales, los servicios interactivos multiplataforma y un mayor control del usuario sobre la escena de vídeo emergen como nuevas formas de llevar la multimedia immersiva e interactiva al mercado de consumo de forma no disruptiva. Sin embargo, existen numerosas interrogantes relativas a los efectos sensoriales y/o soluciones interactivas más adecuadas para complementar un contenido audiovisual determinado o a la mejor manera de de integrar y combinar dichos componentes para mejorar la experiencia de usuario de un segmento de audiencia objetivo. Además, la evidencia científica sobre el impacto de factores humanos en la experiencia de usuario con estas nuevas formas de immersión e interacción en el contexto multimedia es aún insuficiente y en ocasiones, contradictoria. Así, el papel de éstos factores en el potencial de adopción de éstas tecnologías ha sido amplia-mente ignorado. La presente tesis analiza el impacto del audio binaural, efectos sensoriales (de iluminación y olfativos), interacción con objetos 3D integrados en la escena de vídeo e interacción con contenido adicional utilizando una segunda pantalla en la experiencia de usuario con contenidos de deporte. La posible influencia de dichos componentes en las variables dependientes se explora tanto a nivel global (efecto promedio) como en función de las características de los usuarios (efectos heterogéneos). Para ello, se ha llevado a cabo un experimento con usuarios orientado a explorar la influencia de éstos componentes immersivos e interactivos en dos grandes dimensiones de la experiencia multimedia: calidad y Presencia. La calidad de la experiencia multimedia se analiza en términos de las posibles variaciones asociadas a la calidad global y a la calidad del contenido, la imagen, el audio, los efectos sensoriales, la interacción con objetos 3D y la interacción con la segunda pantalla. El posible impacto en la Presencia considera dos de las dimensiones definidas por el cuestionario ITC-SOPI: Presencia Espacial (Spatial Presence) e Implicación (Engagement). Por último, los individuos son caracterizados teniendo en cuenta los siguientes atributos afectivos, cognitivos y conductuales: preferencias y hábitos en relación con el contenido, grado de conocimiento de las tecnologías integradas en el sistema, tendencia a involucrarse emocionalmente, tendencia a concentrarse en una actividad bloqueando estímulos externos y los cinco grandes rasgos de la personalidad: extroversión, amabilidad, responsabilidad, inestabilidad emocional y apertura a nuevas experiencias. A nivel global, nuestro estudio revela que los participantes prefieren el audio binaural frente al sistema estéreo y que los efectos sensoriales generan un aumento significativo del nivel de Presencia Espacial percibido por los usuarios. Además, las manipulaciones experimentales realizadas permitieron identificar una gran variedad de efectos heterogéneos. Un resultado interesante es que dichos efectos no se encuentran distribuidos de forma equitativa entre las medidas de calidad y Presencia. Nuestros datos revelan un impacto generalizado del audio binaural en la mayoría de las medidas de calidad y Presencia analizadas. En cambio, la influencia de los efectos sensoriales y de la interacción con la segunda pantalla se concentran en las medidas de Presencia y calidad, respectivamente. La magnitud de los efectos heterogéneos identificados está modulada por las siguientes características personales: preferencias en relación con el contenido, frecuencia con la que el usuario suele ver contenido similar, conocimiento de las tecnologías integradas en el demostrador, sexo, tendencia a involucrarse emocionalmente, tendencia a a concentrarse en una actividad bloqueando estímulos externos y niveles de amabilidad, responsabilidad y apertura a nuevas experiencias. Las características personales consideradas en nuestro experimento explicaron la mayor parte de la variación en las variables dependientes, confirmando así el importante (y frecuentemente ignorado) papel de las diferencias individuales en la experiencia multimedia. Entre las características de los usuarios con un impacto más generalizado se encuentran las preferencias en relación con el contenido, el grado de conocimiento de las tecnologías integradas en el sistema y la tendencia a involucrarse emocionalmente. En particular, los primeros dos factores parecen generar un conflicto de atención hacia el contenido versus las características/elementos técnicos del sistema, respectivamente. Asimismo, la experiencia multimedia de los fans del fútbol parece estar modulada por procesos emociona-les, mientras que para los no-fans predominan los procesos cognitivos, en particular aquellos directamente relacionados con la percepción de calidad. Abstract Recent studies encourage the integration of multi-sensorial stimuli into multimedia assets to enhance the user experience by stimulating other senses beyond sight and hearing. Similarly, the introduction of multi-modal interaction components complementing with new features, functionalities and/or information the multimedia experience is promoted. Sensory effects as odor, wind, vibration and light effects, as well as an enhanced audio quality, have been found to favour media enjoyment and to have a positive influence on the sense of Presence and on the perceived quality, relevance and reality of a multimedia experience. Two-screen services and a direct manipulation of (elements in) the video scene have the potential to enhance user comprehension, engagement and proactive involvement of/in the media experience. Sports is among the genres that could benefit the most from these solutions. Previous works have demonstrated the technical feasibility of implementing and deploying end-to-end solutions integrating these technologies into legacy systems. Thus, sensorially-enhanced media, two-screen services and an increased user control over the displayed scene emerge as means to deliver a new form of immersive and interactive media experiences to the mass market in a non-disruptive manner. However, many questions remain concerning issues as the specific interactive solutions or sensory effects that can better complement a given audiovisual content or the best way in which to integrate and combine them to enhance the user experience of a target audience segment. Furthermore, scientific evidence on the impact of human factors on the user experience with these new forms of immersive and interactive media is still insufficient and sometimes, contradictory. Thus, the role of these factors on the potential adoption of these technologies has been widely ignored. This thesis analyzes the impact of binaural audio, sensory (light and olfactory) effects, interaction with 3D objects integrated into the video scene and interaction with additional content using a second screen on the sports media experience. The potential influence of these components on the dependent variables is explored both at the overall level (average effect) and as a function of users’ characteristics (heterogeneous effects). To these aims, we conducted an experimental study exploring the influence of these immersive and interactive elements on the quality and Presence dimensions of the media experience. Along the quality dimension, we look for possible variations on the quality scores as-signed to the overall media experience and to the media components content, image, audio, sensory effects, interaction with 3D objects and interaction using the tablet device. The potential impact on Presence is analyzed by looking at two of the four dimensions defined by the ITC-SOPI questionnaire, namely Spatial Presence and Engagement. The users’ characteristics considered encompass the following personal affective, cognitive and behavioral attributes: preferences and habits in relation to the content, knowledge of the involved technologies, tendency to get emotionally involved and tendency to get absorbed in an activity and block out external distractors and the big five personality traits extraversion, agreeableness, conscientiousness, neuroticism and openness to experience. At the overall level, we found that participants preferred binaural audio than standard stereo audio and that sensory effects increase significantly the level of Spatial Presence. Several heterogeneous effects were also revealed as a result of our experimental manipulations. Interestingly, these effects were not equally distributed across the quality and Presence measures analyzed. Whereas binaural audio was foud to have an influence on the majority of the quality and Presence measures considered, the effects of sensory effects and of interaction with additional content through the tablet device concentrate mainly on the dimensions of Presence and on quality measures, respectively. The magnitude of these effects was modulated by individual’s characteristics, such as: preferences in relation to the content, frequency of viewing similar content, knowledge of involved technologies, gender, tendency to get emotionally involved, tendency to absorption and levels of agreeableness, conscientiousness and openness to experience. The personal characteristics collected in our experiment explained most of the variation in the dependent variables, confirming the frequently neglected role of individual differences on the media experience. Preferences in relation to the content, knowledge of involved technologies and tendency to get emotionally involved were among the user variables with the most generalized influence. In particular, the former two features seem to present a conflict in the allocation of attentional resources towards the media content versus the technical features of the system, respectively. Additionally, football fans’ experience seems to be modulated by emotional processes whereas for not fans, cognitive processes (and in particular those related to quality judgment) prevail.

Transforming neural computations and representing time

Motifs of neural circuitry seem surprisingly conserved over different areas of neocortex or of paleocortex, while performing quite different sensory processing tasks. This apparent paradox may be resolved by the fact that seemingly different problems in sensory information processing are related by transformations (changes of variables) that convert one problem into another. The same basic algorithm that is appropriate to the recognition of a known odor quality, independent of the strength of the odor, can be used to recognize a vocalization (e.g., a spoken syllable), independent of whether it is spoken quickly or slowly. To convert one problem into the other, a new representation of time sequences is needed. The time that has elapsed since a recent event must be represented in neural activity. The electrophysiological hallmarks of cells that are involved in generating such a representation of time are discussed. The anatomical relationships between olfactory and auditory pathways suggest relevant experiments. The neurophysiological mechanism for the psychophysical logarithmic encoding of time duration would be of direct use for interconverting olfactory and auditory processing problems. Such reuse of old algorithms in new settings and representations is related to the way that evolution develops new biochemistry.

Dopamine receptor subtypes modulate olfactory bulb γ-aminobutyric acid type A receptors

The γ-aminobutyric acid type A (GABAA) receptor is the predominant Cl− channel protein mediating inhibition in the olfactory bulb and elsewhere in the mammalian brain. The olfactory bulb is rich in neurons containing both GABA and dopamine. Dopamine D1 and D2 receptors are also highly expressed in this brain region with a distinct and complementary distribution pattern. This distribution suggests that dopamine may control the GABAergic inhibitory processing of odor signals, possibly via different signal-transduction mechanisms. We have observed that GABAA receptors in the rat olfactory bulb are differentially modulated by dopamine in a cell-specific manner. Dopamine reduced the currents through GABA-gated Cl- channels in the interneurons, presumably granule cells. This action was mediated via D1 receptors and involved phosphorylation of GABAA receptors by protein kinase A. Enhancement of GABA responses via activation of D2 dopamine receptors and phosphorylation of GABAA receptors by protein kinase C was observed in mitral/tufted cells. Decreasing or increasing the binding affinity for GABA appears to underlie the modulatory effects of dopamine via distinct receptor subtypes. This dual action of dopamine on inhibitory GABAA receptor function in the rat olfactory bulb could be instrumental in odor detection and discrimination, olfactory learning, and ultimately odotopic memory formation.

Predator-induced stress makes the pesticide carbaryl more deadly to gray treefrog tadpoles (Hyla versicolor)

Global declines in amphibians likely have multiple causes, including widespread pesticide use. Our knowledge of pesticide effects on amphibians is largely limited to short-term (4-d) toxicity tests conducted under highly artificial conditions to determine lethal concentrations (LC50). We found that if we used slightly longer exposure times (10–16 d), low concentrations of the pesticide carbaryl (3–4% of LC504-d) killed 10–60% of gray treefrog (Hyla versicolor) tadpoles. If predatory cues also were present, the pesticide became 2–4 times more lethal, killing 60–98% of tadpoles. Thus, under more realistic conditions of increased exposure times and predatory stress, current application rates for carbaryl can potentially devastate gray treefrog populations. Further, because predator-induced stress is ubiquitous in animals and carbaryl's mode of action is common to many pesticides, these negative impacts may be widespread in nature.

CA1-specific N-methyl-d-aspartate receptor knockout mice are deficient in solving a nonspatial transverse patterning task

In both humans and animals, the hippocampus is critical to memory across modalities of information (e.g., spatial and nonspatial memory) and plays a critical role in the organization and flexible expression of memories. Recent studies have advanced our understanding of cellular basis of hippocampal function, showing that N-methyl-d-aspartate (NMDA) receptors in area CA1 are required in both the spatial and nonspatial domains of learning. Here we examined whether CA1 NMDA receptors are specifically required for the acquisition and flexible expression of nonspatial memory. Mice lacking CA1 NMDA receptors were impaired in solving a transverse patterning problem that required the simultaneous acquisition of three overlapping odor discriminations, and their impairment was related to an abnormal strategy by which they failed to adequately sample and compare the critical odor stimuli. By contrast, they performed normally, and used normal stimulus sampling strategies, in the concurrent learning of three nonoverlapping concurrent odor discriminations. These results suggest that CA1 NMDA receptors play a crucial role in the encoding and flexible expression of stimulus relations in nonspatial memory.

Olfactory marker protein (OMP) gene deletion causes altered physiological activity of olfactory sensory neurons.

Olfactory marker protein (OMP) is an abundant, phylogentically conserved, cytoplasmic protein of unknown function expressed almost exclusively in mature olfactory sensory neurons. To address its function, we generated OMP-deficient mice by gene targeting in embryonic stem cells. We report that these OMP-null mice are compromised in their ability to respond to odor stimull, providing insight to OMP function. The maximal electroolfactogram response of the olfactory neuroepithelium to several odorants was 20-40% smaller in the mutants compared with controls. In addition, the onset and recovery kinetics following isoamyl acetate stimulation are prolonged in the null mice. Furthermore, the ability of the mutants to respond to the second odor pulse of a pair is impaired, over a range of concentrations, compared with controls. These results imply that neural activity directed toward the olfactory bulb is also reduced. The bulbar phenotype observed in the OMP-null mouse is consistent with this hypothesis. Bulbar activity of tyrosine hydroxylase, the rate limiting enzyme of catecholamine biosynthesis, and content of the neuropeptide cholecystokinin are reduced by 65% and 50%, respectively. This similarity to postsynaptic changes in gene expression induced by peripheral olfactory deafferentation or naris blockade confirms that functional neural activity is reduced in both the olfactory neuroepithelium and the olfactory nerve projection to the bulb in the OMP-null mouse. These observations provide strong support for the conclusion that OMP is a novel modulatory component of the odor detection/signal transduction cascade.

Expression of Drosophila mushroom body mutations in alternative genetic backgrounds: a case study of the mushroom body miniature gene (mbm).

Mutations in 12 genes regulating Drosophila melanogaster mushroom body (MB) development were each studied in two genetic backgrounds. In all cases, brain structure was qualitatively or quantitatively different after replacement of the "original" genetic background with that of the Canton Special wild-type strain. The mushroom body miniature gene (mbm) was investigated in detail. mbm supports the maintenance of MB Kenyon cell fibers in third instar larvae and their regrowth during metamorphosis. Adult mbm1 mutant females are lacking many or most Kenyon cell fibers and are impaired in MB-mediated associative odor learning. We show here that structural defects in mbm1 are apparent only in combination with an X-linked, dosage-dependent modifier (or modifiers). In the Canton Special genetic background, the mbm1 anatomical phenotype is suppressed, and MBs develop to a normal size. However, the olfactory learning phenotype is not fully restored, suggesting that submicroscopic defects persist in the MBs. Mutant mbm1 flies with full-sized MBs have normal retention but show a specific acquisition deficit that cannot be attributed to reductions in odor avoidance, shock reactivity, or locomotor behavior. We propose that polymorphic gene interactions (in addition to ontogenetic factors) determine MB size and, concomitantly, the ability to recognize and learn odors.

A human axillary odorant is carried by apolipoprotein D.

The characterization of the source of the odor in the human axillary region is not only of commercial interest but is also important biologically because axillary extracts can alter the length and timing of the female menstrual cycle. In males, the most abundant odor component is known to be E-3-methyl-2-hexenoic acid (E-3M2H), which is liberated from nonodorous apocrine secretions by axillary microorganisms. Recently, it was found that in the apocrine gland secretions, 3M2H is carried to the skin surface bound to two proteins, apocrine secretion odor-binding proteins 1 and 2 (ASOB1 and ASOB2) with apparent molecular masses of 45 kDa and 26 kDa, respectively. To better understand the formation of axillary odors and the structural relationship between 3M2H and its carrier protein, the amino acid sequence and glycosylation pattern of ASOB2 were determined by mass spectrometry. The ASOB2 protein was identified as apolipoprotein D (apoD), a known member of the alpha2mu-microglobulin superfamily of carrier proteins also known as lipocalins. The pattern of glycosylation for axillary apoD differs from that reported for plasma apoD, suggesting different sites of expression for the two glycoproteins. In situ hybridization of an oligonucleotide probe against apoD mRNA with axillary tissue demonstrates that the message for synthesis of this protein is specific to the apocrine glands. These results suggest a remarkable similarity between human axillary secretions and nonhuman mammalian odor sources, where lipocalins have been shown to carry the odoriferous signals used in pheromonal communication.

Parasite abundance and diversity in mammals: correlates with host ecology.

Fecally dispersed parasites of 12 wild mammal species in Mudumalai Sanctuary, southern India, were studied. Fecal propagule densities and parasite diversity measures were correlated with host ecological variables. Host species with higher predatory pressure had lower parasite loads and parasite diversity. Host body weight, home range, population density, gregariousness, and diet did not show predicted effects on parasite loads. Measures of alpha diversity were positively correlated with parasite abundance and were negatively correlated with beta diversity. Based on these data, hypotheses regarding determinants of parasite community are discussed.

How caterpillar-damaged plants protect themselves by attracting parasitic wasps.

Parasitic and predatory arthropods often prevent plants from being severely damaged by killing herbivores as they feed on the plants. Recent studies show that a variety of plants, when injured by herbivores, emit chemical signals that guide natural enemies to the herbivores. It is unlikely that herbivore-damaged plants initiate the production of chemicals solely to attract parasitoids and predators. The signaling role probably evolved secondarily from plant responses that produce toxins and deterrents against herbivores and antibiotics against pathogens. To effectively function as signals for natural enemies, the emitted volatiles should be clearly distinguishable from background odors, specific for prey or host species that feed on the plant, and emitted at times when the natural enemies forage. Our studies on the phenomena of herbivore-induced emissions of volatiles in corn and cotton plants and studies conducted by others indicate that (i) the clarity of the volatile signals is high, as they are unique for herbivore damage, produced in relatively large amounts, and easily distinguishable from background odors; (ii) specificity is limited when different herbivores feed on the same plant species but high as far as odors emitted by different plant species and genotypes are concerned; (iii) the signals are timed so that they are mainly released during the daytime, when natural enemies tend to forage, and they wane slowly after herbivory stops.

A receptor guanylyl cyclase expressed specifically in olfactory sensory neurons.

We have cloned an additional member (GC-D) of the membrane receptor guanylyl cyclase [GTP pyrophosphate-lyase (cyclizing), EC 4.6.1.2] family that is specifically expressed in a subpopulation of olfactory sensory neurons. The extracellular, putative ligand-binding domain of the olfactory cyclase is similar in primary structure to two guanylyl cyclases expressed in the retina but diverges considerably from other known guanylyl cyclases. The expression of GC-D RNA is restricted to a small, randomly dispersed population of neurons that is within a single topographic zone in the olfactory neuroepithelium and resembles the pattern of the more diverse seven-transmembrane-domain odorant receptors. These observations suggest that GC-D may function directly in odor recognition or in modulating the sensitivity of a subpopulation of sensory neurons to specific odors.

Interazioni piante - insetti: ruolo delle formiche in un sistema multitrofico. Aspetti ecoetologici ed applicativi

Le formiche svolgono un importante ruolo all’interno degli ecosistemi ed alcune specie sono considerate keystone in quanto in grado di modificare la componente biotica e/o abiotica dell’ecosistema stesso. Sono animali ubiquitari che hanno colonizzato molteplici ambienti, compresi gli agroecosistemi. Negli agroecosistemi spesso svolgono un ruolo impattante determinando la diffusione o il regresso di specie di artropodi, alcune delle quali dannose alle colture. La presente ricerca tiene conto di un’ampia visione dei rapporti ecoetologici intercorrenti tra le formiche e la componente biotica di un ecosistema, utilizzando il concetto di rete multitrofica. In quest’ottica, si è pensato di costruire un sistema multitrofico costituito da una specie vegetale di interesse agrario (Cucumis sativus), dai suoi fitofagi naturali, divisi in fitomizi (afidi) (Aphis gossypii e Myzus persicae) e fitofagi masticatori (bruchi del lepidottero Mamestra brassicae), formiche (Formica pratensis) e predatori afidofagi (Aphidolets aphidimyza). Il sistema multitrofico è stato utilizzato sia per studiare l’aggressività delle formiche, sia per verificare l’esistenza di una comunicazione interspecifica tra le formiche e le piante (allelochimici). Gli studi sull’aggressività sono consistiti nel: • Verificare il livello di aggressività delle formiche nei confronti di un fitofago masticatore, competitore degli afidi nello sfruttare la pianta ospite. • Verificare se la presenza di afidi mutualisti fa variare il livello di aggressività delle formiche verso il competitore. • Verificare se esiste aggressività verso un predatore di afidi, i quali, secondo il paradigma della trofobiosi, dovrebbero essere difesi dalle formiche in cambio della melata. • Verificare se il predatore ha evoluto strategie volte ad eludere il controllo delle formiche sugli insetti che si approcciano alla colonia di afidi. Gli studi sui rapporti piante-formiche sono stati effettuati mediante olfattometro, osservando la risposta delle formiche alle sostanze volatili provenienti da piante infestate in modo differente con i fitofagi del sistema. Attraverso il trappolaggio e l’analisi gas-cromatografica delle sostanze prodotte dalle piante oggetto di studio abbiamo quindi individuato tipo e quantità di ogni composto volatile. Oltre alle piante di cetriolo, per questi esperimenti sono state utilizzate anche piante di patata (Solanum tuberosum). Dagli esperimenti sull’aggressività è risultato che le formiche manifestano un elevato potenziale predatorio, eradicando completamente la presenza dei bruchi sulle piante. Questo livello di aggressività tuttavia non cresce con la presenza degli afidi mutualisti che dovrebbero essere difesi dai competitori. Le formiche inoltre non sono in grado di sopprimere i predatori afidofagi che ipotizziamo riescano ad effettuare un camuffamento chimico, assumendo gli odori degli afidi dei quali si nutrono. I risultati degli esperimenti in olfattometro mostrano una chiara risposta positiva delle formiche verso gli odori di alcune delle piante infestate. Vi sono delle differenze nella risposta in funzione della specie di fitofago presente e della specie di pianta utilizzata. Nei trattamenti in cui erano presenti le piante di C. sativus, gli esperimenti in olfattometro hanno mostrato che le formiche rispondono in modo significativo agli odori emessi dalle piante in cui vi era la presenza del fitofago masticatore M. brassicae, solo o in associazione con A. gossypii. La presenza dei soli afidi, sia mutualisti (A. gossypii) sia non mutualisti (M. persicae), non ha invece indotto una risposta significativa nelle formiche rispetto agli odori delle piante non infestate. Nei trattamenti in cui erano presenti le piante di S. tuberosum la scelta delle formiche è stata significativa verso gli odori emessi dalle piante infestate con ciascuna delle singole specie di erbivori rispetto alle piante non infestate. Gli esperimenti sull’analisi delle sostanze volatili emesse dalle piante hanno confermato che gli organismi vegetali sono una vera centrale di produzione biochimica, infatti ben 91 composti volatili diversi sono stati individuati dall’analisi gas-cromatografica delle piante di cetriolo e 85 in quelle di patata. Dalle elaborazioni effettuate, rispettivamente 27 e 4 di essi sono prodotti esclusivamente dalle piante attaccate dai fitofagi. In generale, il cambiamento più consistente è dato dalla quantità di alcune sostanze volatili emesse dalle piante infestate rispetto a quelle integre che determina un cambiamento nei rapporti tra le sostanze che compongono i volatiles. E’ probabile che l’effetto attrattivo esercitato sulle formiche sia dato da un Blend di sostanze più che dai singoli composti presenti

La cultura política del sandinismo: nacimiento, desarrollo y realineamiento de una anomalía política centroamericana

Sandinista ideology and its political culture are born in 1927, with the refusal of the Pacto del Espino Negro by Augusto César Sandino, while its disappearance can be placed in 1999, date of the signature of the Liberal-Sandinista pact with which –effectively- the two main protagonist of nicaraguan politics at that time, Daniel Ortega and Arnoldo Alemán, halt the democratization process of Nicaragua, so putting on ice also its political development. Meanwhile, in the lapse of time between these two pacts, the most intense, feverish, dramatic and participated period of political history of the Central American country develops: an anti-imperialist guerrilla warfare ended in a bloodbath; a dynastic dictatorship of predatory authoritarianism for more than 40 years; a popular revolution that throws down the dictatorship; a decade of revolutionary government attacked by a counter-revolutionary war; an electoral defeat that will lead to a season of “pactismo” that will end the Sandinista anomaly and that will give an opening to something that we could consider –not with a certain difficulty- its pretence. The aim of this essay consists in analyzing how it has been possible that a political experience like the Sandinista Front , created not only for gaining power and for revolutionizing politically, socially and economically Nicaragua, but also for changing radically cultural, ethic and moral perspective of the country and its people, arrived being the contrary of what had been posed as the horizon to aspire...

Dinâmica de interações intraguilda em Chrysoperla externa (Neuroptera: Chrysopidae), Harmonia axyridis (Coleoptera: Coccinellidae) com Diaphorina citri (Hemiptera: Psyllidae)

A necessidade por recursos alimentares move os insetos predadores na busca por presas, para garantir a sobrevivência. Existem vários fatores que podem influenciar o comportamento de busca e escolha por presas e, sob determinadas circunstâncias, o inseto pode escolher se alimentar de presas não alvo, como, por exemplo, inimigos naturais e assim prejudicar a população de organismos benéficos. Garantir a estabilidade do agroecossistema é uma forma de manter as populações de pragas em níveis compatíveis com a ação de inimigos naturais e, consequentemente obter o sucesso no controle biológico. Programas bem sucedidos de manejo de pragas requerem previamente a realização de estudos sobre comportamento de insetos. Com o intuito de compreender os fatores que governam o comportamento predatório e as interações ecológicas entre Harmonia axyridis e Chrysoperla externa, considerando a presença de Diaphorina citri como presa, objetivou-se estudar o efeito de interações intraguilda sobre a predação de D. citri, experimentalmente e utilizando modelos estatísticos para compreender a dinâmica de interações tróficas no contexto de potenciais guildas presentes em citros. Três experimentos distintos foram realizados para investigar o comportamento dos insetos predadores. Foram realizados testes com escolha entre larvas dos predadores C. externa e H. axyridis e testes com e sem escolha comparando machos e fêmeas do predador H. axyridis, a fim de investigar padrões de escolha de presas. O segundo experimento foi realizado para investigar o comportamento predatório entre larvas de segundo instar dos predadores sob diferentes densidades de D. citri como presa. As combinações foram: sem escolha de presas intraguilda, combinações com escolha de presas intraguilda e combinações com a presença de dois predadores da mesma espécie para possibilitar o canibalismo. As densidades de D. citri utilizadas foram 5, 10, 15, 30, 60, 80. No último experimento avaliou-se a interação entre larvas de C. externa e H. axyridis, ao longo do desenvolvimento, simulando a existência de apenas uma presa, como fonte de alimento. O desenvolvimento dos predadores foi avaliado e comparado utilizando-se duas presas diferentes, ninfas de D. citri e ovos de Ephestia kuehniella para cada larva de primeiro instar dos predadores C. externa e H. axyridis. As combinações de predadores foram as mesmas citadas no experimento anterior. Observou-se a duração do desenvolvimento larval nas diferentes combinações de predadores e presa, bem como o percentual de predações intraguilda e canibalismos ocorridos. Nem a densidade de presas, nem o tipo de presa ofertada influenciou o comportamento das larvas dos predadores para a realização de predação intraguilda ou canibalismo. O principal fator foi a diferença de idade que reflete no tamanho dos predadores, podendo direcionar a predação intraguilda ou o canibalismo e até mesmo acelerar o ciclo de desenvolvimento do predador intraguilda envolvido. Predadores em estágio inicial de vida buscaram por qualquer tipo de presa para garantir sua sobrevivência, não demonstrando qualquer padrão em suas escolhas. No caso dos adultos de H. axyridis, há diferença de comportamento entre os sexos, dependendo da densidade de presas disponíveis, fêmeas poderão ser mais ágeis na busca e consumo de presas.