Rhombic Tilings and Primordia Fronts of Phyllotaxis

We introduce and study properties of phyllotactic and rhombic tilings on the cylin- der. These are discrete sets of points that generalize cylindrical lattices. Rhombic tilings appear as periodic orbits of a discrete dynamical system S that models plant pattern formation by stacking disks of equal radius on the cylinder. This system has the advantage of allowing several disks at the same level, and thus multi-jugate config- urations. We provide partial results toward proving that the attractor for S is entirely composed of rhombic tilings and is a strongly normally attracting branched manifold and conjecture that this attractor persists topologically in nearby systems. A key tool in understanding the geometry of tilings and the dynamics of S is the concept of pri- mordia front, which is a closed ring of tangent disks around the cylinder. We show how fronts determine the dynamics, including transitions of parastichy numbers, and might explain the Fibonacci number of petals often encountered in compositae.Comment: 33 pages, 10 picture

Commuting polynomials and polynomials with same Julia set

It has been known since Julia that polynomials commuting under composition have the same Julia set. More recently in the works of Baker and Eremenko, Fern\'andez, and Beardon, results were given on the converse question: When do two polynomials have the same Julia set? We give a complete answer to this question and show the exact relation between the two problems of polynomials with the same Julia set and commuting pairs

Economic analysis on the impacts of climate change in the maresme coast

L’objectiu principal d’aquesta tesi és desenvolupar una metodologia per a quantificar els impactes del canvi climàtic a nivell local i per a expressar aquest resultat en termes econòmics. En particular, aquest treball considera Catalunya, Espanya, i calcula les pèrdues totals econòmiques que el canvi climàtic pot representar sota un escenari específic per quatre zones costeres vulnerables del Maresme, la comarca al nord de Barcelona. El capítol 2 identifica els efectes del canvi climàtic que s’han de considerar per a calcular les pèrdues totals econòmiques a zones costeres. Basant-se en el coneixement científic actual, intenta presentar les línies de tendència del passat i escenaris pel futur tant a nivell global com al local, per tal d’establir la magnitud dels canvis identificats a escala mundial. No obstant, deixa de banda els impactes que es considera que no provoquin un dany significatiu a la línia del litoral, i conseqüentment els impactes estudiats són la temperatura de l’aire i dels oceans, la precipitació, la salinitat de l’aigua marina i el nivell del mar. En el tercer capítol, es presenta una revisió de la literatura per tal de preparar el desenvolupament d’una metodologia per a calcular els impactes del canvi climàtic. En aquest capítol, diversos estudis, informes i tesis es presenten per a donar una visió general de projectes que ja han encarat un problema similar, o que simplement puguin proporcionar eines pel següent capítol. Després de la revisió de la literatura i basant-se en els seus resultats, es proposa una metodologia en el capítol 4 per tal d’avaluar les pèrdues monetàries que el canvi climàtic pot suposar a nivell local. Es divideix seguint dues perspectives, pèrdues socioeconòmiques i naturals, i una de combinada per a subratllar la particularitat del cas de les platges. Pels impactes socioeconòmics, el valor de les construccions es suma al valor del sòl. També es té en compte les infraestructures de transport, donant un valor per unitat de longitud. Per les pèrdues naturals, s’utilitza el mètode dels serveis d’un ecosistema, considerant un ambient natural com una suma de funcions que representen un benefici per la societat de manera directa o indirecta. En el capítol 5 el cas d’estudi es presenta, on es consideren quatre zones costeres de la regió del Maresme. Seguint la metodologia presentada en el capítol anterior, primerament es realitza la identificació dels usos del sòl. Seguidament, es calculen les àrees i longituds de cada ús del sòl. El tercer pas és valorar en termes econòmics cada subàrea. A continuació s’adopta un criteri de malmès o no-malmès, i cada ús del sòl es considera o bé perdut pels impactes del canvi climàtic o bé roman no malmès. Finalment, les pèrdues totals es calculen pels quatre casos d’estudi sumant el valor de les àrees danyades. El sisè capítol presenta els resultats pels quatre casos d’estudi, així com una visió general de l’estimació de les pèrdues econòmiques total que el canvi climàtic pot representar a la regió del Maresme. El resultat apunta a una pèrdua de 962 M€, que representa el 30% del capital públic del Maresme. En aquest capítol, les limitacions d’aquesta tesi també es presenten, i es suggereixen àrees per futura recerca de les parts que cauen fora de l’abast d’aquest treball.El objetivo principal de esta tesis es desarrollar una metodología para cuantificar los impactos del cambio climático a nivel local y para expresar este resultado en términos económicos. En particular, este trabajo considera Cataluña, España, y calcula las pérdidas totales económicas que el cambio climático puede representar bajo un escenario específico en cuatro zonas costeras vulnerables del Maresme, la comarca al norte de Barcelona. El capítulo 2 identifica los efectos del cambio climático que se tienen que considerar para calcular las pérdidas totales económicas en zonas costeras. Basándose en el conocimiento científico actual, intenta presentar las líneas de tendencia del pasado y escenarios para el futuro tanto a nivel global como local, con tal de establecer la magnitud de los cambios identificados a escala mundial. No obstante, deja de banda los impactos que se considera que no provoquen un daño significativo a la línea del litoral, y consecuentemente los impactos estudiados son la temperatura del aire y los océanos, la precipitación, la salinidad del agua marina y el nivel del mar. En el tercer capítulo, se presenta una revisión de la literatura con tal de preparar el desarrollo de una metodología para calcular los impactos del cambio climático. En este capítulo, diversos estudios, informes y tesis se presentan para dar una visión general de proyectos que ya hayan encarado un problema similar, o que simplemente puedan proporcionar herramientas para el siguiente capítulo. Después de la revisión de la literatura y basándose en sus resultados, se propone una metodología en el capítulo 4 con tal de evaluar las pérdidas monetarias que el cambio climático puede suponer a nivel local. Se divide siguiendo dos perspectivas, pérdidas socioeconómicas y naturales, y una de combinada para subrayar la particularidad del caso de las playas. Para los impactos socioeconómicos, el valor de las construcciones se suma al valor del suelo. También se tiene en cuenta las infraestructuras de transporte, dando un valor por unidad de longitud. Para las pérdidas naturales, se utiliza el método de los servicios de un ecosistema, considerando un ambiente natural como una suma de funciones que representan un beneficio para la sociedad de manera directa o indirecta. En el capítulo 5 el caso de estudio se presenta, donde se consideran cuatro zonas costeras de la región del Maresme. Siguiendo la metodología presentada en el capítulo anterior, primeramente se realiza la identificación de los usos del suelo. Seguidamente, se calculan las áreas y longitudes de cada uso. El tercer paso es valorar en términos económicos cada sub-área. A continuación se adopta un criterio de daño o no-daño, y cada uso del suelo se considera o bien perdido por los impactos del cambio climático o bien permanece no dañado. Finalmente, las pérdidas totales se calculan para los cuatro casos de estudio sumando el valor de las áreas dañadas. El sexto capítulo presenta los resultados para los cuatro casos de estudio, así como una visión general de la estimación de las pérdidas económicas totales que el cambio climático puede representar en la región del Maresme. El resultado apunta a una pérdida de 962 M€, que representa el 30% del capital público del Maresme. En este capítulo, las limitaciones de esta tesis también se presentan, y se sugieren áreas para futuro estudio de las partes que caen fuera del abaste de este trabajo.The main aim of this thesis is to develop a methodology to quantify the impacts of climate change on a local level and to express this result in economic terms. In particular, this project looks at Catalunya, Spain, and calculates the total economic losses that climate change may represent under a certain scenario for four vulnerable coastal zones in the Maresme, a region north of Barcelona. Chapter 2 identifies the climate change effects which must be considered when calculating the total economic losses in coastal zones. Based on the current scientific knowledge, it attempts to present past trends and future scenarios in both the global and local level, in order to establish the magnitude of the reported global changes. However, it leaves aside the impacts which are considered not to damage the coastal line in a significant matter, and hence the studied impacts are air and ocean temperature, precipitation, sea water salinity and mean sea level. In the third chapter, a literature review is presented in order to pave the road for the development of a methodology to calculate the impacts of climate change. In this chapter, several studies, reports and thesis are presented to give an overview of projects which have already tackled a similar problem, or which simply may provide tools for the following chapter. Following the literature overview and based on its results, a methodology is proposed in chapter 4 to evaluate the economic losses that climate change may have on a local level. It is divided following two perspectives, socioeconomic and natural losses, and a combined one underlining the particularity of the case of beaches. For socioeconomic impacts, the construction or buildings value is added to the land value. Transportation infrastructure is also accounted for, giving a per length unit value. As for natural losses, the ecosystem services approach is taken, by considering a natural environment as a sum of functions which represent a benefit to human society in a direct or indirect way. In the chapter 5 the case study is presented where four coastal zones of the Maresme region in Catalunya are studied. Following the methodology presented in the previous chapter, firstly, the identification of land uses is carried out. Then, the areas and lengths for each land use are calculated. The third step is to valuate in economic terms each subarea. Afterward a loss or unharmed criterion is adopted, in a similar way to pass/fail criteria, and each land use is considered to be lost to the impacts of climate change or to remain unharmed. Finally, the total losses are calculated in all four case studies by adding up the value of all the harmed areas. The sixth chapter presents the results for the four case studies, as well as a general overview of the estimated economic losses that climate change may represent for the Maresme region. The results point to a 962 M€ total loss, which represents 30% of the Maresme public capital. In this chapter, the limitations of this thesis are also presented, and future research is suggested in the areas that fall out of the scope of this study

The Politics of Agricultural Carbon Finance: The Case of the Kenya Agricultural Carbon Project

ESR

Rhombic Tilings and Primordia Fronts of Phyllotaxis

We introduce and study properties of phyllotactic and rhombic tilings on the cylin- der. These are discrete sets of points that generalize cylindrical lattices. Rhombic tilings appear as periodic orbits of a discrete dynamical system S that models plant pattern formation by stacking disks of equal radius on the cylinder. This system has the advantage of allowing several disks at the same level, and thus multi-jugate config- urations. We provide partial results toward proving that the attractor for S is entirely composed of rhombic tilings and is a strongly normally attracting branched manifold and conjecture that this attractor persists topologically in nearby systems. A key tool in understanding the geometry of tilings and the dynamics of S is the concept of pri- mordia front, which is a closed ring of tangent disks around the cylinder. We show how fronts determine the dynamics, including transitions of parastichy numbers, and might explain the Fibonacci number of petals often encountered in compositae

Farmers’ Agency and Experiences of Agricultural Change in Rural Kenya: Insights from Exploratory Fieldwork

Using novel agricultural technologies to boost farm productivity in the face of climatic and demographic disruption remains a priority for African policy and research. This paper uses an innovative, participatory and ethnographic methodology to explore, through farmers’ experiences, the historical pathways of social, ecological and technical (socio-eco-technical) change that have reshaped agriculture, livelihoods and rural landscapes in three sites in Kenya (Machakos, Siaya and Kisumu Counties) over recent decades. The paper identifies events and processes that triggered major changes in farming systems at household and community levels. Insights from engagements with farmers reflect an evolution in the strategic direction of agricultural development in Kenya from a more ‘bureaucratic’ mode during the colonial and immediate post-independence periods to a more ‘technocratic’ mode today. In the bureaucratic mode, the state was at the centre and aspired to align all farming practices and technologies with the priorities and programmes determined by the national government. In the contemporary period of technocratic development, agricultural programmes and interventions have been designed by scientific experts and implemented by technical agencies through the institutional form of short-term projects and programmes. In both the bureaucratic and technocratic systems, the agency of local farmers has remained weak and constrained. Both systems of management established formal development processes and power structures that largely sidelined meaningful contributions by ordinary farmers to technological change processes. We argue that the agency and capacities of farmers and rural communities, to make choices and respond to opportunities arising from or introduced into their local situations, should be recognised as an important engine of socio-eco-technical transformations towards a sustainable future for African agriculture. We therefore propose that this exploratory study helps to build a platform for further research both conceptually and methodologically, with the potential to inform the design and implementation of future agricultural development interventions

A Dynamical System for Plant Pattern Formation: A Rigorous Analysis

We present a rigorous mathematical analysis of a discrete dynamical system modeling plant pattern formation. In this model, based on the work of physicists Douady and Couder, fixed points are the spiral or helical lattices often occurring in plants. The frequent occurrence of the Fibonacci sequence in the number of visible spirals is explained by the stability of the fixed points in this system, as well as by the structure of their bifurcation diagram. We provide a detailed study of this diagram

PRISE project 4 : enabling private sector adaptation in semi arid areas : country workshop : Laikipia

The presentation reports on Pathways to Resilience in Semi-Arid Economies (PRISE) Project 4. This phase investigates the private sector, especially Micro, Small and Medium Enterprises (MSMEs) including findings on women-led SMEs, and how they can adapt to climate change. Small and medium enterprises play a key role in supporting livelihoods and economic growth in semi- arid regions such as Laikipia (Kenya). The Kenyan semi-arid lands (SALs) host over 10 million people (25% of the country’s population) who draw their livelihoods from natural resources and associated enterprises. Support of SME through combined financial and gender policy, microcredit and climate funds is critical

Relationship Between Personality Types and Career Choice Among Undergraduate Students of Maseno University, Kenya

Training institutions in most parts of the world place high premium on those who excel in examinations based on scholastic intelligence. In Kenya, students are admitted into available undergraduate degree programmes in public universities based on their performance in Kenya Certificate of Secondary Education (KCSE). Yet, the Bachelor of Education (B.Ed) degree programmes offered in the School of Education at Maseno University have a strong bearing on personality types and not all the students admitted can fit in them. Academic qualification remains a challenge to a majority of students (79.4%) in choosing a career; hence a significant number (94%) of students end up settling for what is available rather than their choice. Apparently, limited attention has been given to exploring the relationship between students’ unique personality-occupational interests hence the current low (7%) college career satisfaction level.  The purpose of the study therefore, was to establish the types of personality and their relationship with career choice among first-year B.Ed students of Maseno University, Kenya. The objectives of the study was to establish Holland personality types across gender; to determine the level of relationship between personality types and career choice in the B.Ed programmmes of Maseno University  The study was guided by the Holland Code Theory (1997). Correlation and descriptive survey designs were adopted for the study. The target population consisted of the 490 first-year B.Ed students admitted in the Academic year 2011/2012 in the School of Education. The study sample consisted of 220 first-years B.Ed students drawn using proportionate stratified sampling. Data was collected by use of Questionnaire and document analysis guides. The questionnaire was piloted using 10% (n = 49) of the study population Pearson Product Moment correlation was used to determine reliability at alpha level 0.05. The questionnaire had an acceptable reliability index of 0.84. Quantitative data was coded and analyzed using descriptive statistics such as mode, frequency counts and percentages. Gender difference in personality types was examined using percentages and mean gender differences across personality types. Further, the degree of relationship between personality types and career choice was established using cross tabulation with chi-square test and Likelihood Ratio test. Qualitative data was transcribed into text form of emerging themes and reported. Gender was found to be strongly correlated to personality types (X = 34.962, df= 5, p= .000) with more males classified as realistic and investigative and more females as social type. The results of the of the chi square test likelihood ratio test show very high (p<.000) level of relationship between personality types and career choice. The study concludes that students at Maseno University can be classified into the six Holland personality types which correlate significantly with gender. The study further concludes that there is also a significant relationship (p<.000) between personality types and career choice. The study recommended that the need to investigate factors at the university environment which influences the development of personality types among female and male students. Significantly, the study provides a useful guide to students, education policymakers and university staff for career choice, training and retention efforts and placement. Keywords: Personality, Gender, Career choice, degree program DOI: 10.7176/JEP/11-14-14 Publication date:May 31st 202