2,155 research outputs found
Investigating the foraging ecology and energy requirements of a seabird population increasing in an intensely exploited marine environment
Their high energetic demands make seabirds sensitive to changes in prey availability, which is often reflected in their diet and energetic expenditure during breeding. Populations of the three seabirds endemic to southern Africa's Benguela upwelling ecosystem that rely on small pelagic fish have decreased dramatically over the last decade. In contrast, the population of the greater crested tern Thalasseus bergii has increased. To understand these conflicting trends, I investigated the foraging ecology and energy requirements of greater crested tern breeding in the Western Cape, South Africa. Diet was assessed by a novel non-invasive methodology developed in this study, using digital photography. More than 24,000 prey items from at least 51 different prey taxa were identified, with 34 new prey species recorded, revealing a high degree of foraging plasticity for this seabird. Greater crested terns rely mainly on anchovy Engraulis encrasicolus (65%), which averaged 84 mm long. Prey composition differed significantly between breeding stages, with anchovy especially dominant at the onset of the breeding period and the diet becoming more variable as the season progressed. Time-energy models for breeding terns were built based on activity budgets collected from non-invasive video-recordings and focal observations. Foraging trips were significantly longer during incubation than the chick provisioning stages, and feeding rates doubled from early to late chick provisioning. This study illustrated a steady increase in energy needs of adults throughout the breeding season, due to their increased foraging effort to meet chick energy needs. In comparison to other Benguela endemic seabirds that also rely on small pelagic fish, terns displayed substantially lower energy requirements at both individual and population levels. I also explored the benefits underlying interactions within mixed-species aggregations by investigating the costs induced by kleptoparasitism between mixed colonies of greater crested terns and Hartlaub's gulls Chroicocephalus hartlaubii and colonies with greater crested terns alone. Video-recordings coupled with focal observations showed that terns suffer direct costs to chick provisioning rates and indirect costs through energy expenditure in a mixed-species colony, suggesting that these breeding assemblages may be a form of parasitism rather than a mutualistic association. Despite the detrimental effects of interspecific kleptoparasitism, the marked foraging plasticity and low energetic requirements of greater crested terns, described in this study, coupled with specific life history traits such as low fidelity to breeding sites and extended post-fledging care, are key factors that allow this species to cope with changes in the availability and abundance of their main prey. Understanding species-specific behavioural responses to ecosystem variations in the Benguela upwelling system is vital for assessing the impact of commercial fisheries on seabird populations and fish stocks. Finally, the implementation of the method developed in this study, in long-term monitoring programmes, may provide crucial knowledge for conservation plans and key input to realising an ecosystem approach to fisheries management
Psychological Needs Satisfaction in Teaching: A Mixed Methods Analysis on the Impact of Evaluation Systems on Teacher Intrinsic Motivational Outcomes Using Self-Determination Theory
The purpose of this study is to examine the relationships between psychological need satisfaction, motivational regulators, and intrinsic motivational outcomes regarding teacher evaluation systems related to the self-determination theory. The study consisted of 144 participants from two school districts and 18 school buildings. Confirmatory factor analysis and structural equation modeling showed that psychological need satisfaction positively predicted autonomous motivation and in turn, positively predicted enjoyment and pressure, while also negatively predicting value. Psychological need satisfaction also negatively predicted controlled motivation with autonomy and competence, but positively predicted relatedness. Controlled motivation positively predicted enjoyment, but negatively predicted pressure and value. Twenty participants were interviewed and a thematic analysis concluded two main themes: Teacher evaluations do not hold value for teachers and evaluations do not increase motivation. Thematic analysis also concluded four subthemes: (a) autonomy and peer competence promoted value and enjoyment, (b) relatedness improves all motivational indexes and adds value, (c) evaluations do not increase pressure, and (d) improvement plans do not influence motivation. These findings can help provide insight into how teacher evaluation systems could change for the better, giving teachers a greater sense of value and motivation and increasing teacher retention
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Adaptive routing in active networks
New conceptual ideas on network architectures have been proposed in the recent past. Current store-andforward
routers are replaced by active intermediate systems,
which are able to perform computations on transient packets,
in a way that results very helpful for developing and
deploying new protocols in a short time. This paper introduces a new routing algorithm, based on a congestion
metric, and inspired by the behavior of ants in nature. The
use of the Active Networks paradigm associated with a cooperative learning environment produces a robust, decentralized algorithm capable of adapting quickly to changing conditions
Improving bioavailability of insoluble payloads through PLGA nanotechnology
Bioactive molecules are a cluster of natural or synthetic compounds, which modu- late actions in the body promoting good health. Furthermore, they have been ap- plied in the prevention of cancer, heart disease, and other diseases for their antiox- idant, anti-inflammatory, anti-microbial, anti-cancer properties. Among them, many are hydrophobic or poorly soluble nutrients, such as phenolic compounds, ca- rotenoids, essential oils, essential fatty acids, insoluble peptides, and vitamins. Their low water solubility is the limiting factor for their use in both nutraceutical and pharmacological industries. In fact, drugs with poor water solubility show a slower absorption rate, which can lead to inadequate bioavailability making the drug ineffective. Furthermore, hydrophobic molecules can also be used as bio- probe for imaging purpose. Narrow bandwidth emissions and large Stokes shifts make lanthanide complexes interesting as versatile molecular probes of biological systems. Nevertheless, they are not widely used for imaging purpose since their luminescence is completely quenched in aqueous environment. In this scenario, nanoencapsulation through the use of polymeric nanoparticles (NPs ) could be an effective solution to improve solubility and protection of the insoluble payload with consequent increase in bioavailability and action. Poly lac- tic-co-glycolic acid (PLGA) is a synthetic copolymer of lactic acid and glycolic acid of remarkable interest for potential applications in biomedicine; indeed, for its biodegradability and biocompatibility, it has been approved for human use both by Food and Drug Administration (FDA) and European Medicine Agency (EMA). In this thesis, we want to give several proofs of concept about the huge potentiality of PLGA nanoparticles in medical purpose. We used single emulsion methos (O/W) to encapsulate natural bioactive molecules producing planted-derived PLGA nanocarriers enabling anti-inflammatory and antioxidant activity when the polyphe- nol Oxyresveratrol has been incorporated into PLGA NPs. Moreover, an osteogenic promoting action has been observed when PLGA NPs have been embedded with Fisetin (a natural flavonoid).Since PLGA can deliver more than one payload simultaneously, we also produced PLGA nanoassemblies able to combine antibacterial activity with physical treat- ments (such as magnetic and photothermic hyperthermia). Finally, we exploited the shielding properties of PLGA to preserve the luminescence of NIR-emitting lantha- nide complexes in aqueous environment. Therefore, we produced a NIR-CPL probe based on PLGA for bioassay imaging. To summarise, during the past three years we were able to use PLGA encapsulation technology to make natural or synthetic compounds bioavailable, even if naturally water insoluble, and use the loaded nanomaterials in in-vitro experiments assessing the activity of the encapsulated material, paving the way for their application in in- vivo tests and eventual use in nanomedicine
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Fast training of self organizing maps for the visual exploration of molecular compounds
Visual exploration of scientific data in life science
area is a growing research field due to the large amount of
available data. The Kohonen’s Self Organizing Map (SOM) is
a widely used tool for visualization of multidimensional data.
In this paper we present a fast learning algorithm for SOMs
that uses a simulated annealing method to adapt the learning
parameters. The algorithm has been adopted in a data analysis
framework for the generation of similarity maps. Such maps
provide an effective tool for the visual exploration of large and
multi-dimensional input spaces. The approach has been applied
to data generated during the High Throughput Screening
of molecular compounds; the generated maps allow a visual
exploration of molecules with similar topological properties.
The experimental analysis on real world data from the
National Cancer Institute shows the speed up of the proposed
SOM training process in comparison to a traditional approach.
The resulting visual landscape groups molecules with similar
chemical properties in densely connected regions
Development of a business model for Industry 4.0 based on industrial analytics
Over the last few years, the manufacturing sector has changed and is continuing to change due
to the use of new technologies resulting from the advent of the fourth industrial revolution
(Industry 4.0), such as the Internet of Things (IoT), technology whose importance is becoming
increasingly recognized by citizens, businesses and governments and which is proving capable
of changing not only our daily way of life, but also the way companies carry out their activities,
redefining the relationships between companies themselves and their customers, employees and
partners. This technology also allows the exploitation of new Industrial Analytics processes,
which allow companies to perform a systematic computational analysis of data and statistics in
order to better interpret such data, applying models that make the decision-making process more
effective.
The goal of this thesis is to develop a new business model for Industry 4.0 based on Industrial
Analytics. This model intends to act as a starting point and help for all those companies that
want to install IoT solutions or platforms based for Industrial Analytics.
The methodology used to achieve this goal has consisted in administering a questionnaire to 3
companies, with the aim of understanding how these companies are changing their way of doing
business thanks to the advent of the IoT, of Industrial Analytics. and other technologies that are
part of the Industry 4.0 context. The analysis of the responses to the questionnaire was the basis
for the development of the business models of the three companies interviewed. Finally, by
comparing the three models, a new business model for Industry 4.0 based on Industrial
Analytics was developed.Nos últimos anos, o setor industrial mudou e continua mudando devido ao uso de novas
tecnologias decorrentes da quarta revolução industrial (Indústria 4.0), tais como a Internet of
Things (IoT); esta é uma tecnologia cuja importância está a ser cada vez mais reconhecida por
cidadãos, empresas e governos e que se mostra capaz de mudar não só o nosso quotidiano, mas
também a forma como as empresas desenvolvem as suas atividades, redefinindo as relações
com os seus clientes, colaboradores e parceiros. A IoT viabiliza ainda a exploração de novos
processos de Industrial Analytics, que permitem às empresas realizar uma análise
computacional sistemática de dados e estatísticas conducente a uma melhor interpretação dos
mesmos, aplicando modelos que tornam mais eficaz o processo de tomada de decisão.
O objetivo desta tese é desenvolver um novo modelo de negócios para a Indústria 4.0 baseado
em "Industrial Analytics". Este modelo pretende ser um ponto de partida e ajudar todas as
empresas que pretendam instalar soluções IoT ou plataformas baseadas em "Industrial Analytics".
A metodologia utilizada para atingir este objetivo consistiu na aplicação de um questionário a
três empresas, com o objetivo de compreender como elas estão a mudar a sua forma de fazer
negócio graças ao advento da IoT, da "Industrial Analytics" e de outras tecnologias que fazem
parte do âmbito da Indústria 4.0. A análise das respostas ao questionário serviu de base para o
desenvolvimento dos modelos de negócio das três empresas entrevistadas. Finalmente,
desenvolveu-se um novo modelo de negócio para a Indústria 4.0 com base na análise avançada
de dados industriais e por comparação dos três modelos previamente concebidos
Le tissu productif numérique en France
Amorcée clairement au début des années 2000, la transformation numérique fait
l'objet de nombreuses études qui en soulignent le caractère prometteur et exaltant
(Brynjolfsson et MacAfee, 2014) bien que bouleversant et polarisant, appelant donc des
adaptations des politiques publiques (Haskel et Westlake, 2018). Dans ce Policy brief, on
s'intéresse à la dimension productive de cette transformation numérique. Cette dernière
est au centre des débats sur les transformations du tissu productif, du marché de l'emploi,
de la concentration du pouvoir économique et de l'énigme de la productivité. Pour en
saisir les enjeux, il faut commencer par l'évaluer.
Ce Policy brief propose une évaluation de la numérisation du tissu productif français en
utilisant une grille sectorielle mais en doublant l'évaluation de la production de numérique
par celle de la consommation des branches en numérique. Par l'entrée de la production,
on capture la création de « matières premières » numériques : les ordinateurs, les puces,
les éléments électroniques mais aussi les services d'ingénierie informatique, les logiciels, les
services de télécommunications, etc. Par l'entrée de la consommation, nous mesurons
l'intensité numérique par secteur qui rapporte la consommation intermédiaire du secteur
en « matières premières » numérique au total de la consommation intermédiaire du
secteur. Des comparaisons internationales permettent de situer la France relativement à
ses principaux partenaires.
Cette approche de la dimension numérique du tissu productif français permet d'établir
que la France se situe dans une position médiane qui appelle une plus forte mobilisation
des acteurs pour rejoindre les pays de tête. Comme ailleurs, le tissu productif français a
profité, depuis le début des années 2000, de la baisse des prix des services des télécommunications
et des prix du manufacturier numérique. L'accélération de la numérisation de
l'économie passera par une augmentation de l'intensité numérique du tissu productif en
services d'ingénierie informatique et numérique, ce qui contribuera à développer le
secteur lui-même ainsi que les exportations de services. De la vitalité de ces services et de
leur capacité à répondre aux besoins des autres secteurs dépendra la numérisation du tissu
productif
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