The nature of alkanethiol self-assembled monolayer adsorption on sputtered gold substrates

A detailed study of the self-assembly and coverage by 1-nonanethiol of sputtered Au surfaces using molecular resolution atomic force microscopy (AFM) and scanning tunneling microscopy (STM) is presented. The monolayer self-assembles on a smooth Au surface composed predominantly of {111} oriented grains. The domains of the alkanethiol monolayer are observed with sizes typically of 5-25 nm, and multiple molecular domains can exist within one Au grain. STM imaging shows that the (4 × 2) superlattice structure is observed as a (3 × 2√3) structure when imaged under noncontact AFM conditions. The 1-nonanethiol molecules reside in the threefold hollow sites of the Au{111} lattice and aligned along its lattice vectors. The self-assembled monolayer (SAM) contains many nonuniformities such as pinholes, domain boundaries, and monatomic depressions which are present in the Au surface prior to SAM adsorption. The detailed observations demonstrate limitations to the application of 1-nonanethiol as a resist in atomic nanolithography experiments to feature sizes of ∼20 nm.

Influence of Outlet Boundary Conditions on Cerebrovascular Aneurysm Hemodynamics

Computational fluid dynamic (CFD) studies of blood flow in cerebrovascular aneurysms have potential to improve patient treatment planning by enabling clinicians and engineers to model patient-specific geometries and compute predictors and risks prior to neurovascular intervention. However, the use of patient-specific computational models in clinical settings is unfeasible due to their complexity, computationally intensive and time-consuming nature. An important factor contributing to this challenge is the choice of outlet boundary conditions, which often involves a trade-off between physiological accuracy, patient-specificity, simplicity and speed. In this study, we analyze how resistance and impedance outlet boundary conditions affect blood flow velocities, wall shear stresses and pressure distributions in a patient-specific model of a cerebrovascular aneurysm. We also use geometrical manipulation techniques to obtain a model of the patient’s vasculature prior to aneurysm development, and study how forces and stresses may have been involved in the initiation of aneurysm growth. Our CFD results show that the nature of the prescribed outlet boundary conditions is not as important as the relative distributions of blood flow through each outlet branch. As long as the appropriate parameters are chosen to keep these flow distributions consistent with physiology, resistance boundary conditions, which are simpler, easier to use and more practical than their impedance counterparts, are sufficient to study aneurysm pathophysiology, since they predict very similar wall shear stresses, time-averaged wall shear stresses, time-averaged pressures, and blood flow patterns and velocities. The only situations where the use of impedance boundary conditions should be prioritized is if pressure waveforms are being analyzed, or if local pressure distributions are being evaluated at specific time points, especially at peak systole, where the use of resistance boundary conditions leads to unnaturally large pressure pulses. In addition, we show that in this specific patient, the region of the blood vessel where the neck of the aneurysm developed was subject to abnormally high wall shear stresses, and that regions surrounding blebs on the aneurysmal surface were subject to low, oscillatory wall shear stresses. Computational models using resistance outlet boundary conditions may be suitable to study patient-specific aneurysm progression in a clinical setting, although several other challenges must be addressed before these tools can be applied clinically.

Collection of measurements on environmental conditions in plots of the Jena Experiment (time series since 2002)

This collection contains measurements of environmental conditions measured on the plots of the different sub-experiments at the field site of a large grassland biodiversity experiment (the Jena Experiment; see further details below). In the main experiment, 82 grassland plots of 20 x 20 m were established from a pool of 60 species belonging to four functional groups (grasses, legumes, tall and small herbs). In May 2002, varying numbers of plant species from this species pool were sown into the plots to create a gradient of plant species richness (1, 2, 4, 8, 16 and 60 species) and functional richness (1, 2, 3, 4 functional groups). Plots were maintained by bi-annual weeding and mowing. The following series of datasets are contained in this collection: 1.Soil temperature measurements on plots of the Main Experiment; 2. Quantification of the duration that individual plots of the Main Experiment were submerged during a flooding event occurring in June 2013

Molecular basis of canalization in an ascidian species complex adapted to different thermal conditions

Canalization is a result of intrinsic developmental buffering that ensures phenotypic robustness under genetic variation and environmental perturbation. As a consequence, animal phenotypes are remarkably consistent within a species under a wide range of conditions, a property that seems contradictory to evolutionary change. Study of laboratory model species has uncovered several possible canalization mechanisms, however, we still do not understand how the level of buffering is controlled in natural populations. We exploit wild populations of the marine chordate Ciona intestinalis to show that levels of buffering are maternally inherited. Comparative transcriptomics show expression levels of genes encoding canonical chaperones such as Hsp70 and Hsp90 do not correlate with buffering. However the expression of genes encoding endoplasmic reticulum (ER) chaperones does correlate. We also show that ER chaperone genes are widely conserved amongst animals. Contrary to previous beliefs that expression level of Heat Shock Proteins (HSPs) can be used as a measurement of buffering levels, we propose that ER associated chaperones comprise a cellular basis for canalization. ER chaperones have been neglected by the fields of development, evolution and ecology, but their study will enhance understanding of both our evolutionary past and the impact of global environmental change.

Molecular basis of canalization in an ascidian species complex adapted to different thermal conditions

Canalization is a result of intrinsic developmental buffering that ensures phenotypic robustness under genetic variation and environmental perturbation. As a consequence, animal phenotypes are remarkably consistent within a species under a wide range of conditions, a property that seems contradictory to evolutionary change. Study of laboratory model species has uncovered several possible canalization mechanisms, however, we still do not understand how the level of buffering is controlled in natural populations. We exploit wild populations of the marine chordate Ciona intestinalis to show that levels of buffering are maternally inherited. Comparative transcriptomics show expression levels of genes encoding canonical chaperones such as Hsp70 and Hsp90 do not correlate with buffering. However the expression of genes encoding endoplasmic reticulum (ER) chaperones does correlate. We also show that ER chaperone genes are widely conserved amongst animals. Contrary to previous beliefs that expression level of Heat Shock Proteins (HSPs) can be used as a measurement of buffering levels, we propose that ER associated chaperones comprise a cellular basis for canalization. ER chaperones have been neglected by the fields of development, evolution and ecology, but their study will enhance understanding of both our evolutionary past and the impact of global environmental change.

Stone temperature and moisture variability under temperate environmental conditions: implications for sandstone weathering

Temperature and moisture conditions are key drivers of stone weathering processes in both natural and built environments. Given their importance in the breakdown of stone, a detailed understanding of their temporal and spatial variability is central to understanding present-day weathering behaviour and for predicting how climate change may influence the nature and rates of future stone decay.
Subsurface temperature and moisture data are reported from quarry fresh Peakmoor Sandstone samples exposed during summer (June–July) and late autumn / early winter (October–December) in a mid-latitude, temperate maritime environment. These data demonstrate that the subsurface thermal response of sandstone comprises numerous short-term (minutes), low magnitude fluctuations superimposed upon larger-scale diurnal heating and cooling cycles with distinct aspect-related differences. The short-term fluctuations create conditions in the outer 5–10 mm of stone that are much more ‘energetic’ in comparison to the more subdued thermal cycling that occurs deeper within the sandstone samples.
Data show that moisture dynamics are equally complex with a near-surface region (5–10 mm) in which frequent moisture cycling takes place and this, combined with the thermal dynamism exhibited by the same region may have significant implications for the nature and rate of weathering activity. Data indicate that moisture input from rainfall, particularly when it is wind-driven, can travel deep into the stone where it can prolong the time of wetness. This most often occurs during wetter winter months when moisture input is high and evaporative loss is low but can happen at any time during the year when the hydraulic connection between near-surface and deeper regions of the stone is disrupted with subsequent loss of moisture from depth slowing as it becomes reliant on vapour diffusion alone.
These data illustrate the complexity of temperature and moisture conditions in sandstone exposed to the ‘moderate’ conditions of a temperate maritime environment. They highlight differences in thermal and moisture cycling between near-surface (5–10 mm) and deeper regions within the stone and contribute towards a better understanding of the development of structural and mineralogical heterogeneity between the stone surface and substrate.

Printmare Against Nature

Nicky Coutts showed a work in the show "Printmare: Against Nature 1", reproducing a miniature storm scene from a Scottish five pound note and an essay titled "Animal Print Suicide" for the accompanying publication "Printmare Against Nature 2". Curated by Finlay Taylor, ‘Against Nature’ was an exhibition exploring conditions of current understandings of geography (or the geo-graphical), natural histories and landscapes. This exhibition concentrated on work that uses print, and the ways in which subtle innovations in this medium are used to investigate some of the complexities that arise when looking at nature in art. An associated publication has been published by Camberwell Press with essays by David Cross and Nicky Coutts, as well as page images by Bob Matthews, Denis Masi, Finlay Taylor, Kate Scrivener and Dick Jewell. Exhibiting artists included Franz Ackermann, Jasone Miranda Bilbao, Sarah Bodman, Ian Brown, Helen Chadwick, Paul Coldwell, Cornford and Cross, Nicky Coutts, Dunhill & O’Brien, Adam Gillam, Oona Grimes, Judith Goddard, Mark Harris, Katsushika Hokusai, Dan Howard-Birt, Susan Johanknecht, James Keith, Serena Korda, Michael Landy, Jo Love, Mike Marshall, Bob Matthews, Julian Opie, Tim O’Riley, Simon Patterson, David Rayson, Rebecca Salter, Kate Scrivener, Jo Stockham, and Herman de Vries.

Vitamines B, éléments clés de l'efficacité métabolique : Effets de la nature de la diète sur les apports

Les travaux sur la nutrition en vitamines B des ruminants montrent des résultats très variés sur les quantités de ces nutriments disponibles pour l’animal selon la nature de la ration. Ces divergences sont dues à des changements des populations microbiennes dans le rumen, causées par les facteurs physico-chimiques de la ration. Une amélioration de la compréhension des effets de la nature de la diète sur la synthèse et l’utilisation des vitamines B dans le rumen pourrait aider à identifier les conditions sous lesquelles une supplémentation en ces vitamines serait bénéfique pour la vache. Le but de ce travail de thèse est donc d’améliorer la compréhension des effets de l’espèce fourragère, de la maturité et de la longueur des particules de fourrage sur les apports en vitamines B chez la vache laitière. Pour évaluer chacune de ces variables, les concentrations de thiamine, riboflavine, niacine, vitamine B6, folates et vitamine B12 ont été mesurées dans les échantillons d’aliments et de digesta duodénal recueillis lors de trois projets réalisés à l’Université du Michigan par l’équipe du Dr. M. Allen. Dans la première étude, l’effet de l’espèce fourragère des ensilages a été évalué au cours de deux expériences similaires durant lesquelles les vaches recevaient une diète à base d’ensilage de luzerne ou de dactyle. Les diètes à base de luzerne ont été associées à une augmentation de la dégradation de la thiamine et de la vitamine B6 dans le rumen par rapport aux diètes à base d’ensilage de dactyle. La deuxième étude visait à évaluer les effets de la maturité des plantes lors de la mise en silo sur les quantités de vitamines B disponibles pour la vache; les deux expériences se différenciaient par l’espèce fourragère étudiée, soit la luzerne ou le dactyle. Une récolte à un stade de maturité plus élevé a augmenté les flux duodénaux de thiamine, de niacine et de folates lorsque les vaches recevaient des diètes à base d’ensilage de luzerne mais n’a diminué que le flux duodénal de riboflavine chez les animaux recevant des diètes à base d’ensilage de dactyle. La troisième étude a comparé les effets de la longueur de coupe (10 vs. 19 mm) d’ensilages de luzerne et de dactyle sur le devenir des vitamines B dans le système digestif de la vache laitière. Cette étude a permis de constater qu’une augmentation du temps de séchage au champ diminuait les concentrations de vitamines B dans les ensilages. Cependant, la taille des particules des ensilages de luzerne et de dactyle n’a pas affecté les quantités des vitamines B arrivant au duodénum des vaches. En général, les résultats de ces études montrent qu’il existe une corrélation négative entre la synthèse de riboflavine, de niacine et de vitamine B6 et leur ingestion, suggérant une possible régulation de la quantité de ces vitamines B par les microorganismes du rumen. De plus, l’ingestion d’amidon et d’azote a été corrélée positivement avec la synthèse de thiamine, de folates et de vitamine B12, et négativement avec la synthèse de niacine. Ces corrélations suggèrent que les microorganismes qui utilisent préférentiellement l’amidon jouent un rôle majeur pour la synthèse ou la dégradation de ces vitamines. De plus, la présence d’une quantité suffisante d’azote semble avoir un impact majeur sur ces processus. La suite de ces travaux devrait viser la modélisation de ces données afin de mieux appréhender la physiologie de la digestion de ces vitamines et permettre la création de modèles mathématiques capables de prédire les quantités de vitamines disponibles pour les vaches. Ces modèles permettront, lorsqu’intégrés aux logiciels de formulation de ration, d’élaborer une diète plus précise, ce qui améliorera la santé du troupeau et la performance laitière et augmentera les profits du producteur.

Mothers’ perception of recovery and satisfaction with patent medicine dealers’ treatment of childhood febrile conditions in rural communities

Background Infant mortality in rural areas of Nigeria can be minimized if childhood febrile conditions are treated by trained health personnel, deployed to primary healthcare centres (PHCs) rather than the observed preference of mothers for patent medicine dealers (PMDs). However, health service utilization/patronage is driven by consumer satisfaction and perception of services/product value. The objective of this study was to determine ‘mothers’ perception of recovery’ and ‘mothers’ satisfaction’ after PMD treatment of childhood febrile conditions, as likely drivers of mothers’ health-seeking behaviour, which must be targeted to reverse the trend. Methods Ugwuogo-Nike, in Enugu, Nigeria, has many PMDs/PHCs, and was selected based on high prevalence of childhood febrile conditions. In total, 385 consenting mothers (aged 15–45 years) were consecutively recruited at PMD shops, after purchasing drugs for childhood febrile conditions, in a cross-sectional observational study using a pre-tested instrument; 33 of them (aged 21–47 years) participated in focus group discussions (FGDs). Qualitative data were thematically analysed while a quantitative study was analysed with Z score and Chi square statistics, at p < 0.05. Results Most participants in FGDs perceived that their child had delayed recovery, but were satisfied with PMDs’ treatment of childhood febrile conditions, for reasons that included politeness, caring attitude, drug availability, easy accessibility, flexibility in pricing, shorter waiting time, their God-fearing nature, and disposition as good listeners. Mothers’ satisfaction with PMDs’ treatment is significantly (p < 0.05) associated with mothers’ perception of recovery of their child (χ2 = 192.94, df = 4; p < 0.0001; Cramer’s V = 0.7079). However, predicting mothers’ satisfaction with PMDs’ treatment from a knowledge of mothers’ perception of recovery shows a high accord (lambda[A from B] = 0.8727), unlike when predicting mothers’ perception of recovery based on knowledge of mothers’ satisfaction with PMDs’ treatment (lambda[A from B] = 0.4727). Conclusions Mothers’ satisfaction could be the key ‘driver’ of mothers’ health-seeking behaviour and is less likely to be influenced by mothers’ perception of recovery of their child. Therefore, mothers’ negative perception of their child’s recovery may not induce proportionate decline in mothers’ health-seeking behaviour (patronage of PMDs), which might be influenced mainly by mothers’ satisfaction with the positive attributes of PMDs’ personality/practice and sets an important agenda for PHC reforms.

A Utilitarian Perspective of Social and Medical Contributions to Three Illustrative Conditions, and Recent UK NHS Policy Initiatives

Background: To date debate concerning the relative merits of social and medical sciences has been largely academic. Aims: To outline and critically appraise a utilitarian approach to mental health research that reflects a critical realist perspective. Method: Consideration of the relative utility of differing approaches to illustrative ‘‘psychiatric’’ disorders, and recent policy initiatives. Results: Socially relevant outcomes of Bipolar Affective Disorder are determined by influences that operate independently of the characteristic instability of mood. There is now a highly specific and effective psychological treatment for Panic Disorder. Its benefits are still not fully exploited because of continuing lay and professional focus upon the condition’s social manifestations. Great numbers of people presenting in primary care are unhelpfully caused to adopt the role of ‘‘patient’’ due to practices limiting the professional response to a medical one. Such practices reflect public and professional perceptions of the nature of ‘‘mental health difficulties’’ much more than they do the achievements of medicine. Recent policy-supporting initiatives influencing UK NHS mental health services are much more likely to be supported by social sciences than by medical research. Conclusions: There is considerable scope for a contribution to applied mental health research from frameworks and methodologies that are rooted in a social sciences perspective.

Evolution of strength and physical properties of ultramafic and carbonate rocks under hydrothermal conditions

Interaction of rocks with fluids can significantly change mineral assemblage and structure. This so-called hydrothermal alteration is ubiquitous in the Earth’s crust. Though the behavior of hydrothermally altered rocks can have planet-scale consequences, such as facilitating oceanic spreading along slow ridge segments and recycling volatiles into the mantle at subduction zones, the mechanisms involved in the hydrothermal alteration are often microscopic. Fluid-rock interactions take place where the fluid and rock meet. Fluid distribution, flux rate and reactive surface area control the efficiency and extent of hydrothermal alteration. Fluid-rock interactions, such as dissolution, precipitation and fluid mediated fracture and frictional sliding lead to changes in porosity and pore structure that feed back into the hydraulic and mechanical behavior of the bulk rock. Examining the nature of this highly coupled system involves coordinating observations of the mineralogy and structure of naturally altered rocks and laboratory investigation of the fine scale mechanisms of transformation under controlled conditions. In this study, I focus on fluid-rock interactions involving two common lithologies, carbonates and ultramafics, in order to elucidate the coupling between mechanical, hydraulic and chemical processes in these rocks. I perform constant strain-rate triaxial deformation and constant-stress creep tests on several suites of samples while monitoring the evolution of sample strain, permeability and physical properties. Subsequent microstructures are analyzed using optical and scanning electron microscopy. This work yields laboratory-based constraints on the extent and mechanisms of water weakening in carbonates and carbonation reactions in ultramafic rocks. I find that inundation with pore fluid thereby reducing permeability. This effect is sensitive to pore fluid saturation with respect to calcium carbonate. Fluid inundation weakens dunites as well. The addition of carbon dioxide to pore fluid enhances compaction and partial recovery of strength compared to pure water samples. Enhanced compaction in CO2-rich fluid samples is not accompanied by enhanced permeability reduction. Analysis of sample microstructures indicates that precipitation of carbonates along fracture surfaces is responsible for the partial restrengthening and channelized dissolution of olivine is responsible for permeability maintenance.

Pricing recreation use of national parks for an efficient nature conservation : an application to the portuguese case

Current institutions, research, and legislation have not yet been sufficient to achieve the conservation level of Nature as required by the society. One of the reasons that explains this relative failure is the lack of incentives to motivate local individual and Nature users in general, to adopt behaviour compliant with Nature sustainable uses. Economists believe that, from the welfare point of view, pricing is the more efficient way to make economic actors to take more environmental friendly decisions. In this paper we will discuss how efficient can be the act of pricing the recreation use of a specific natural area, in terms of maximising welfare. The main conservation issues for pricing recreation use, as well as the conditions under which pricing will be an efficient and fair instrument for the natural area will be outlined. We will conclude two things. Firstly that, from the rational utilitarian economic behaviour point of view, economic efficiency can only be achieved if the natural area has positive and known recreation marginal costs under the relevant range of the marshallian demand recreation curve and if price system management is not costly. Secondly, in order to guarantee equity for the different type of visitors when charging the fee, it is necessary to discuss differential price systems. We shall see that even if marginal recreation costs exist but are unknown, pricing recreation is still an equity instrument and a useful one from the conservation perspective, as we shall demonstrate through an empirical application to the Portuguese National Park. An individual Travel Cost Method Approach will be used to estimate the recreation price that will be set equal to the visitor’s marginal willingness to pay for a day of visit in the national park. Although not efficient, under certain conditions this can be considered a fair pricing practice, because some of the negative recreation externalities will be internalised. We shall discuss the conditions that guarantee equity on charging for the Portuguese case.

A novel approach to reduce fire exposure and promote nature conservation in Mediterranean ecosystems: the case study of Reserva Natural da Serra da Malcata, Portugal

Mestrado Mediterranean Forestry and Natural Resources Management - Instituto Superior de Agronomia - UL

Le langage chez Descartes dans la réflexion sur la nature des animaux

Descartes pose l’identité entre l’animal et la machine sur le plan de leur nature. Le présent texte examine l’importance de la notion de langage dans l’expérience de pensée de Descartes portant sur l’animal, et ce, à partir du test du langage présenté dans le Discours de la méthode. L’échec au test du langage témoigne de leur incapacité à manifester des aptitudes langagières minimales ce qui supporte le jugement cartésien voulant que les animaux soient des machines dénuées d’âme et de pensée. De plus, le discours sur la nature des animaux est l’occasion de faire valoir le caractère universel de la raison.

Cognitive and Visual Speech Contributions to Speech Perception in Challenging Listening Conditions

Speech perception routinely takes place in noisy or degraded listening environments, leading to ambiguity in the identity of the speech token. Here, I present one review paper and two experimental papers that highlight cognitive and visual speech contributions to the listening process, particularly in challenging listening environments. First, I survey the literature linking audiometric age-related hearing loss and cognitive decline and review the four proposed causal mechanisms underlying this link. I argue that future research in this area requires greater consideration of the functional overlap between hearing and cognition. I also present an alternative framework for understanding causal relationships between age-related declines in hearing and cognition, with emphasis on the interconnected nature of hearing and cognition and likely contributions from multiple causal mechanisms. I also provide a number of testable hypotheses to examine how impairments in one domain may affect the other. In my first experimental study, I examine the direct contribution of working memory (through a cognitive training manipulation) on speech in noise comprehension in older adults. My results challenge the efficacy of cognitive training more generally, and also provide support for the contribution of sentence context in reducing working memory load. My findings also challenge the ubiquitous use of the Reading Span test as a pure test of working memory. In a second experimental (fMRI) study, I examine the role of attention in audiovisual speech integration, particularly when the acoustic signal is degraded. I demonstrate that attentional processes support audiovisual speech integration in the middle and superior temporal gyri, as well as the fusiform gyrus. My results also suggest that the superior temporal sulcus is sensitive to intelligibility enhancement, regardless of how this benefit is obtained (i.e., whether it is obtained through visual speech information or speech clarity). In addition, I also demonstrate that both the cingulo-opercular network and motor speech areas are recruited in difficult listening conditions. Taken together, these findings augment our understanding of cognitive contributions to the listening process and demonstrate that memory, working memory, and executive control networks may flexibly be recruited in order to meet listening demands in challenging environments.