The gut microbiome plays a vital role in human health. Disturbances of this microbial system is associated with diseases such as obesity and inflammatory bowel disease. In populations of microbial species, many organisms partake in byproduct cross-feeding interactions, where byproducts from one organism are consumed by other microbes. Using the digital evolution software Avida, I studied the effect of recurring perturbations and imperfect resource conversion on the evolution of byproduct cross-feeding chains in digital communities. To investigate the effect of perturbation and conversion rate on digital organisms, I evolved digital communities for 200,000 updates in an unperturbed environment that could hold 50 different resource types, each produced as a byproduct of consuming another resource. At 200,000 updates, 50 or 60 % of all organisms were removed at various intervals during periods of different lengths, with a conversion rate less than 100 % between resources in the byproduct chain. I found that 0.9 conversion rate caused communities to evolve longer cross-feeding chains. A conversion rate of 0.5 resulted in communities with much shorter chains, more similar in length to byproduct chains in the human gut. Perturbation events seem to affect chain length only under certain conditions when energy is lost between resources, for example when 60 % of all organisms were removed every 50th update on average. It appears that conversion loss makes digital communities more robust against the effects of perturbations, and that it might protect these communities from going extinct.

The human gut microbiome is a complex ecosystem with hundreds of species interacting with each other and the host. One function of the microbiome is to break down undigested nutrients into smaller nutrients, sometimes available for uptake by the host. The digestion of such macromolecules can involve several species where one feeds on another’s byproducts, forming a large cross-feeding network. The method of digital evolution can be of great aid in studying such complex ecosystems by creating models of the studied system. In this study, the digital evolution software Avida was used to study the effects of perturbations in the system on byproduct cross-feeding chain length. Intense perturbations were found to shorten the chain lengths in general whereas weaker perturbations had either a small or no effect. When perturbations ceased, most byproduct chains displayed recovery to lengths similar to the preperturbation lengths. This indicates that byproduct chain lengths may be kept short by common ecological mechanisms alone, explaining why very long chains are rarely observed while still theoretically possible.

This thesis is on Cognitive Science of Religion (CSR) and its relevance for the rationality of religious beliefs. An epistemical model for rationality is developed according to which: a person (or group of persons) is rational to hold a certain belief a) if this belief can be assumed to have been generated by one or more reliable cognitive mechanisms, b) applies whether or not she is aware of what these mechanisms are, but c) only as long as it does not exist or arise some reasons (defeaters) to question the belief; if they occur, she must d) reflect on it and find other reasons or grounds to hold the belief in question.      Two different positions are examined, namely: 1) negative relevance: the findings and theories in CSR undermines the rationality of religious beliefs; 2) positive relevance: religious beliefs need not be irrational in the light of CSR, in fact CSR may actually support the rationality of religious beliefs.      Two lines of argument can be distinguished among those who argue for a negative relevance: a) the natural explanations that are provided by CSR are preferable; and b) religious beliefs are irrational because they are caused by unreliable cognitive mechanisms.      Among those who argue for positive relevance two arguments can be distinguised: a) religious beliefs seem to come naturally to humans and therefore are probably true; and b) CSR confirms empirically that we are equipped with a "divine mechanism" that there are reasons to believe is reliable.      The conclusions are: CSR has negative relevance to beliefs in "finite supernatural agency", but not for the faith of "infinite supernatural agency". First, the first type of beliefs is easier to explain by being generated by unreliable cognitive mechanisms; secondly they are difficult to integrate with what we otherwise know about the world. A category that falls outside the scope of CSR and thus not even potentially can be affected, is beliefs in "supernatural non-agency". / The Impact of Religion – Challenges for Society, Law and Democracy

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This trial was composed of two experiments. In the first the objective of was ascertain this chemical characteristics of theof the silage of orange bagasse pre-dried ( SOB ) as well as this fermentative characteristics at different storage times. In the second experiment the objective was to determine the effect of replacement of maize by sob, in the of Santa Inês lambs and cost benefit of the diets. In the first experiment was conduced in laboratorial PVC mini silo with 10 cm diameter and 70 cm long, with a capacity of about 10 kg which are sealed with a lid equipped with a valve PVC "Bunsen" type. Adopted a distributed in a completely randomized design with five treatments and six replications . The treatments were different opening times of mini silos in days (10, 20, 40, 60 and 80). It was determined the chemical and fermentation parameters . The values of DM, CP , NDF , lignin and TDN did not suffer influence of opening days . The pre - drying increased the dry matter content of 28.3 % . Reduction in the ADF and increase in MM to advance the days of ensiling . The pH decreased during the days of storage , since the values of ammonia nitrogen did not vary . The values for dry matter losses and gases decreased after 60 days of storage , since the RMS did not change in relation to treatments . The orange peel can be stored efficiently in preserving their nutrients over the form of silage. According to the results found in this work silage orange has good nutritional value . In the second experiment 20 lambs with approximately 150 days of age and average weight (BW ) of 25 kg were fed for 73 days or until they reached 35 kg, fed diets with increasing levels of SBL replacing corn ( 0 , 33 , 66 and 100 % DM ) . There was a decline in dry matter intake (DMI) in g / day and% PV that showed average values of 914.62 g / day and 2.75 % BW respectively. Only FDA intake in g / day and% PV was not influenced by the inclusion of the SBL , all other nutrients ( DM, OM , CP, MM, NDF , and TDN ) decreased . The average daily gain ( ADG ) decreased with the inclusion of SBL and days on feed increased but feed conversion was not affected . The feed cost was reduced with the inclusion of the SBL . The replacement levels of 33 % and 66 showed better cost-benefit ratio , and the level of 66 % replacement of corn by SBL as indicated in the conditions of the present work . / O trabalho foi composto de dois experimentos no primeiro objetivou-se determinar as características químicas e bromatológicas da silagem do bagaço de laranja pré-seco (SBL) bem como suas características fermentativas em diferentes tempos de armazenamento, no segundo experimento objetivou-se determinar o efeito da substituição do milho pela SBL no desempenho de cordeiros da raça Santa Inês e no custo benefício das dietas utilizadas. No primeiro experimento foram utilizados mini silos laboratoriais de PVC com 10 cm de diâmetro e 70 cm de comprimento, com capacidade de aproximadamente 10 kg, sendo estes vedados com uma tampa de PVC dotada de uma válvula tipo "Bunsen". Adotou-se um delineamento inteiramente casualizado, com cinco tratamentos e seis repetições. Sendo os tratamentos diferentes tempos de abertura dos mini silos em dias (10, 20, 40, 60 e 80). Determinou-se as características químicas e os parâmetros de fermentação. Os valores de MS, PB, FDN, lignina e NDT não sofreram influencia dos dias de abertura. A pré-secagem aumentou o teor de matéria seca em 28,3%. Houve redução nos teores de FDA e aumento na MM ao avançar dos dias de ensilagem. O pH apresentou redução durante os dias de armazenamento, já os valores de nitrogênio amoniacal não variaram. Os valores para perdas de matéria seca e gases apresentaram redução a partir dos 60 dias de armazenamento, já a RMS não variou em relação aos tratamentos. O bagaço de laranja pode ser conservado com eficiência na preservação de seus nutrientes sobre a forma de silagem. De acordo com os resultados encontrados neste trabalho a silagem de bagaço de laranja apresenta bom valor nutricional. No segundo experimento, foram utilizados 20 cordeiros com aproximadamente 150 dias de idade e media de peso vivo (PV) de 25 kg que permaneceram confinados por 73 dias ou até que atingissem 35kg, foram alimentados com dietas contendo níveis crescentes de SBL em substituição ao milho (0, 33, 66 e 100% MS). Houve declínio da ingestão de matéria seca (IMS) em g/dia e em %PV que apresentaram valores médios de 914,62 g/dia e 2,75%PV respectivamente. Apenas a ingestão de FDA em g/dia e em % PV não foi influenciada com a inclusão da SBL, todos os outros nutrientes (MS, MO, PB, MM, FDN, e NDT) apresentaram redução. O ganho de peso diário (GPD) reduziu com a inclusão da SBL e os dias de confinamento aumentados, porém a conversão alimentar não foi influenciada. O custo da ração apresentou redução com a inclusão da SBL. Os níveis de substituição de 33 e 66% apresentaram melhor relação custo benefício, sendo o nível de 66% de substituição do milho pela SBL o mais indicado nas condições do presente trabalho.

Made available in DSpace on 2014-07-29T15:13:41Z (GMT). No. of bitstreams: 1 Eduardo Rodrigues de Carvalho.pdf: 1237820 bytes, checksum: d8bf044399d1192242219f8c2afee68b (MD5) Previous issue date: 2010-12-06 / The expansion of the biofuel industry has generated increased availability of glycerol, which can be used as an ingredient in the ration of dairy cows. This study aimed to determine the effects of glycerol on DMI, milk production, production of SCFA in the rumen, blood parameters, selective consumption and feeding behavior of dairy cows periparturientes. Twenty-six multiparous Holstein cows were paired according to performance in the previous lactation and expected date of calving and fed diets containing glycerol or high moisture corn from -28 to +56 DRDP. Glycerol was included in 11.5 and 10.8% of total DM in the diet pre-and post-partum respectively. CMS has not changed (P> 0.05) by feeding with glycerol both pre-partum (14.9 vs. 14.6 kg / day, vs control. glycerol) and the post-partum (19.8 vs. 20.7 kg / day, vs control. Glycerol), as well as production (35.8 vs. 37 kg / day, vs control. glycerol) and milk composition did not differ (P> 0.05) between treatments. The concentration of blood glucose was reduced (P <0.05, vs 59.1. 53.4 mg / dL vs control. glycerol) and ABHB blood was elevated (P <0.05, 0.58 vs. 0.82 mmol / L vs control. glycerol) in cows fed glycerol during pre-partum. The concentration of NEFA in the blood did not differ (P> 0.05) between experimental groups in the pre-partum, and no effect (P> 0.05) on the glycerol blood parameters during the postpartum period. The total concentration of SCFA in rumen (mmol / L) did not differ (P> 0.05) between treatments, but increased (P <0.05) in the molar proportion of propionate (22.7 vs. 28.6% vs control. Glycerol) and butyrate (11.5 vs. 15.3% vs control. glycerol) and reduced (P <0.05) in proportion molar acetate (61.5 vs. 51.5% vs control. glycerol) in cows fed with glycerol. In relation to the selective consumption and ingestive behavior, there increase (P <0.05) the rate of DMI (94.2 vs. MS 144.4 g / h vs. control. glycerol) and preferential consumption (9.2 vs. 17.8% vs control. glycerol) long particle with glycerol in the diet, but decreased (P <0.05) the rate of CMS short particles (383.8 vs. MS 332.5 g / h vs. control. glycerol) and very short (173.9 vs. MS 129.8 g / h vs. control. Glycerol) and increased (P <0.05) in rejecting short particles (42 vs. 37.3% vs control. glycerol) and very short (17.9 vs. 13.6% vs control. glycerol) during pre-partum. No effect (P> 0.05) of treatments on the selective use of particles of the diet in the postpartum period and also on the feeding behavior throughout the experimental period. The data obtained in this study indicated that replacing corn wet grain by glycerol in diets for dairy cows was periparturientes satisfactory. / A expansão da indústria de biocombustíveis tem gerado aumento na disponibilidade do glicerol, o qual pode ser utilizado como ingrediente na ração de vacas leiteiras. Objetivou-se nesse estudo determinar os efeitos do glicerol sobre o CMS, produção de leite, produção de AGCC no rúmen, parâmetros sanguíneos, consumo seletivo e comportamento ingestivo de vacas leiteiras periparturientes. Vinte e seis vacas multíparas da raça Holandesa foram pareadas de acordo com o desempenho na lactação anterior e data prevista de parição, e alimentadas com dietas contendo glicerol ou milho grão úmido desde -28 até +56 DRDP. O glicerol foi incluído em 11,5 e 10,8% do total da MS nas dietas pré e pós-parto, respectivamente. O CMS não foi alterado (P>0,05) pela alimentação com glicerol tanto no pré-parto (14,9 vs. 14,6 kg/dia, controle vs. glicerol) quanto no pós-parto (19,8 vs. 20,7 kg/dia, controle vs. glicerol), assim como a produção (35,8 vs. 37 kg/dia, controle vs. glicerol) e composição de leite não diferiram (P>0,05) entre os tratamentos. A concentração de glucose no sangue foi reduzida (P<0,05; 59,1 vs. 53,4 mg/dL, controle vs. glicerol) e de ABHB no sangue foi elevada (P<0,05; 0,58 vs. 0,82 mmol/L, controle vs. glicerol) nas vacas alimentadas com glicerol durante o pré-parto. A concentração de AGNE no sangue não diferiu (P>0,05) entre os grupos experimentais no pré-parto, e não houve efeito (P>0,05) do glicerol sobre os parâmetros sanguíneos durante o pós-parto. A concentração total de AGCC no rúmen (mmol/L) não diferiu (P>0,05) entre os tratamentos, mas houve aumento (P<0,05) na proporção molar de propionato (22,7 vs. 28,6%, controle vs. glicerol) e butirato (11,5 vs. 15,3%, controle vs. glicerol) e redução (P<0,05) na proporção molar de acetato (61,5 vs. 51,5%, controle vs. glicerol) nas vacas alimentadas com glicerol. Em relação ao consumo seletivo e comportamento ingestivo, houve aumento (P<0,05) na taxa do CMS (94,2 vs. 144,4 g MS/h; controle vs. glicerol) e no consumo preferencial (9,2 vs. 17,8%; controle vs. glicerol) de partículas longas na dieta com glicerol, porém houve redução (P<0,05) na taxa do CMS de partículas curtas (383,8 vs. 332,5 g MS/h; controle vs. glicerol) e muito curtas (173,9 vs. 129,8 g MS/h; controle vs. glicerol) e aumento (P<0,05) na rejeição de partículas curtas (42 vs. 37,3%; controle vs. glicerol) e muito curtas (17,9 vs. 13,6%; controle vs. glicerol) durante o pré-parto. Não houve efeito (P>0,05) dos tratamentos sobre o consumo seletivo de partículas da dieta no pós-parto e também sobre o comportamento ingestivo durante todo o período experimental. Os dados obtidos na presente pesquisa indicaram que a substituição do milho grão úmido pelo glicerol em dietas para vacas leiteiras periparturientes foi satisfatória.