Miracle-dz/UniFAR-FTUs huggingface dataset:
The Initiation of Gastrular Ingression in the Chick Blastoderm

Normal gastrular ingression in the chick blastoderm occurs in two steps. The first consists in de-epithelialization of the cells in the middle of the young primitive streak. The cells that will ingress converge as a sheet towards the primitive streak; this convergence builds up the elongating primitive streak. These cells come from a large posterior area of the area pellucida. In this area they show many blebs at their ventral side. These blebs are not visible in the more lateral regions of the upper layer at this stage. During the second step of ingression, de-epithelialization goes on in the middle of the primitive streak, but convergence within the upper layer has come to an end, while migration of the ingressed middle layer cells starts, away from the primitive streak. To observe the first stages of ingression, we studied secondary primitive streaks, induced by grafting a nodus posterior into the entophyllic crescent of a host blastoderm. We fixed blastoderms in which, though a secondary primitive streak was not yet visible, spreading of the graft had taken place so as to make evocation of a streak most probable. From this study we conclude that the initiation of de-epithelialization in experimental and probably in normal chick gastrulation is not preceded by an overall lysis of the basal lamina at the future site of ingression. Ingression starts and goes on as a de-epithelialization of individual cells.
Wolbachia's Role In Classical Speciation Theory

Wolbachia are intracellular bacteria that commonly infect arthropod species. Since they often induce a cytoplasmic mating incompatibility (CI) in their hosts that acts as a postzygotic isolating mechanism between differently infected individuals of one species, Wolbachia have received attention as a potential promoter of arthropod speciation processes. Previous studies on speciation focused on either Wolbachia-induced or the classical nuclear-based postzygotic isolating mechanism. However, it should usually be the case that both co-occur. This thesis continues investigations on Wolbachia’s role in speciation by analyzing interactions of Wolbachia-induced CI and nuclear incompatibility (NI) caused by genetic differentiation. We will show that Wolbachia has strong impact on nuclear-based speciation processes. In particular, synergy effects can occur when both isolating mechanisms act simultaneously. Furthermore, we show that Wolbachia can influence speciation processes under more general conditions than previous studies on Wolbachia’s role in speciation suggested. Since the actual role of Wolbachia in arthropod speciation will strongly depend on their abundance, we present a statistical meta-analysis of published data on Wolbachia infection frequencies. Due to the sampling methods applied in studies on Wolbachia infection frequencies, it is likely that current estimates of 20% infected species are underestimates. This is supported by our analysis and we show that more likely about two-thirds of species are infected. Combining both results, this thesis provides strong evidence forWolbachia being a very general factor in arthropod speciation processes.
Tooth-Like Scales in Early Devonian Eugnathostomes and the ‘Outside-In’ Hypothesis for the Origins of Teeth in Vertebrates

ABSTRACT Although teeth are considered one of the most important steps in vertebrate evolution, details of their origins are obscure. Two prominent and opposing theories for the evolution of the vertebrate dentition are current: the ‘Outside-in’ hypothesis and the ‘inside-out’ hypothesis. One of the main arguments against the ‘outside-in’ hypothesis is that, although similarities between teeth and scales have been observed, there is little fossil evidence of transitional forms between the two structures. Specimens of ischnacanthid acanthodians from the Man On The Hill (MOTH) locality in the Mackenzie Mountains of Canada provide the first unequivocal example of such transitional forms in an Early Devonian (Lochkovian) vertebrate assemblage. The head scales of these specimens are modified with proximity to the mouth to be extremely tooth-like. Three distinct morphotypes of modified cheek and lip scales are described. Their detailed similarity to teeth suggests that they are a result of the same developmental processes, and also suggests the existence of a field of gene expression near the mouth margin in which scales could be transformed into teeth. These transitional forms remove one of the chief objections to the ‘outside-in’ hypothesis for the origins of teeth in vertebrates.
Edge‐effects Drive Tropical Forest Fragments Towards an Early‐Successional System

O futuro da biodiversidade das florestas tropicais e dos serviços ambientais prestados por este ecossistema está intrinsecamente ligado a nossa habilidade de entender as mudanças deflagradas pela fragmentação de habitats e por outras forças que dirigem a dinâmica biológica em paisagens antrópicas. Neste artigo nós reunimos evidências empíricas e teóricas para argumentar que os efeitos de borda deflagram um processo sucessional rápido e inevitável, o qual conduz a maioria dos fragmentos de florestas neotropicais em direção a um sistema sucessional inicial. Este tipo de sistema emerge e persiste uma vez que os efeitos de borda favorecem, de forma permanente, um pequeno grupo de espécies pioneiras redundantes em detrimento de um grupo muito diverso de espécies que compõe as florestas maduras. Esta mudança na direção de um sistema inicial representa um conjunto de processes inter‐relacionados, a qual define a assinatura dos ambientes expostos aos efeitos de borda em termos de estrutura de comunidades e do funcionamento do ecossistema. Nossa intenção é que este ensaio estimule a investigação e, também, uma melhor compreensão das forças que determinam a natureza dos ecossistemas em paisagens alteradas pela ação antrópica. Esta compreensão é um passo fundamental para a definição de normas do uso da terra que sejam capazes de ampliar o papel das paisagens antrópicas em termos de retenção de biodiversidade e prestação de serviços ambientais.
Relating genotype and phenotype for tryptophan synthesis in an aphid–bacterial symbiosis

The symbiotic bacteria Buchnera provide their aphid hosts with tryptophan and other essential amino acids. Tryptophan production by Buchnera varied among 12 parthenogenetic clones of the pea aphid Acyrthosiphon pisum (Harris), as determined from both the incorporation of radioactivity from 14C‐anthranilate into tryptophan and the protein‐tryptophan growth rate of larval aphids on tryptophan‐free diet. The values of tryptophan production obtained for the two methods were correlated significantly with each other but not with the level of amplification of the Buchnera genes trpEG, which code for anthranilate synthase, a key enzyme in tryptophan biosynthetic pathway. This study provides the first direct demonstration of interclonal variation in production of any nutrient in an aphid–Buchnera symbiosis and indicates that a key aspect of Buchnera phenotype (tryptophan production) does not vary in a simple fashion with Buchnera genotype.
An Evaluation of Methionine Hydroxy Analog Free Acid Using A Nonlinear (Exponential) Bioassay

Abstract Two experiments were conducted to determine the bioefficacy of methionine hydroxy analog free acid (MHA-FA) using the nonlinear (exponential) bioassay method. Male broiler chicks were fed a low methionine diet composed primarily of ground yellow corn and soybean meal for the 1st wk. The experimental diets, which varied in eight levels of DL-methionine and in eight equimolar levels of MHA-FA, were fed from 7 to 21 days of age. The source of protein was soybean meal and isolated soybean meal (15% of each) in the first experiment and soybean meal and peanut meal (23 and 21%, respectively) in the second experiment with glucose as the primary source of energy. Compared with DL-methionine on an equimolar basis, the bioefficacy of the MHA-FA was 72 ± 5 and 73 ± 7% using weight gains and feed conversions, respectively, from the first experiment and 85 ± 11 and 79 ± 8% using weight gain and feed conversion from the second experiment. These results clearly show that DL-methionine is much superior to MHA-FA on an equimolar basis.
Temporal and spatial correlation in chick production of willow grouse Lagopus lagopus in Sweden and Norway

Abstract We analysed the spatial and temporal dynamics of chick production of willow grouse Lagopus lagopus in the Swedish and Norwegian mountain region using harvest data covering 24–38 years and line-transect counts covering 6–10 years from the period 1960–2003. Juvenile and adult grouse were counted in the bag of harvested willow grouse in late August and throughout September at six sites in Sweden and Norway. In addition, numbers of juvenile and adult willow grouse were obtained from line-transect counts at 21 sites in Sweden just before the hunting season started on 25 August. The juvenile:adult ratio from the harvest data, estimated as number of juveniles per two adults, showed similar long-term averages and distributions between all six sites. The results from the line-transect counts revealed an overall higher average and a greater range of production between sites. We suggest that the difference between estimates based on line-transect counts and harvest data are caused by hunter behaviour. Hunters did not sample the juvenile and adult grouse in proportion to what was present in the population, e.g., productivity estimates derived from harvest samples will underestimate the proportion of juveniles in autumn in most years. We suggest that it is the harvest process that acts to adjust the juvenile to old bird ratio in the harvest data to a similar distribution in different sites. We found little evidence of regular fluctuations/cycles in annual production of juveniles from either harvest data or line-transect data. We conclude that chick production in willow grouse appears to fluctuate more irregularly than was previously believed based on harvest data and can not be used as a potential forecasting tool in willow grouse management as suggested earlier. Spatial correlation was weak and investigating only a limited number of sites to predict the proportion of juveniles in autumn should not be considered as a management tool for large areas such as the state-owned land in Sweden. Line-transect counts are costly, but do provide a more accurate estimate of the proportion of juveniles in the fall population than is revealed by harvest data. A more detailed understanding of hunter behaviour is obviously needed for better interpretation of harvest data.
Genetic variations and antibiotic resistance patterns of Staphylococcus aureus isolates from human and bovine

L'etude a ete realisee pour estimer le lien genetique existant entre 96 isolats de Staphylococcus aureus d'origine humaines et bovines par electrophorese en champ pulse (PFGE) ainsi que pour etudier les profils de resistance des isolats a 11 agents antimicrobiens par l'E-essai. Sur les 96 isolats, 45 types distincts de PFGE ont ete identifies. Ils ont ete repartis en 18 groupes de lignee notes A a S. L'analyse de Cluster a prouve que des genotypes bacteriens sont associes a une suele espece hote. Les genotypes des souches d'origine humaine etaient plus heterogenes. Soixante-seize pour cent des isolats bovins et 34 % des isolats humains ont ete assignes au groupe S et K respectivement. Approximativement 70 % de s souches MRSA ont ete inclus dans le groupe K et la comparaison des souches MSSA et MRSA a prouve qu'elles ne sont pas etroitement liees. Excepte pour des socuhes MRSA, on n'a pas observe de niveau important de correlation entre les profils de resistance antimicrobiens et les pulsotypes des isolats. Alors que la resistance a la peniciline etait 100 % dans les souches d'origine humaine et 80.4 % dans les isolats bovins, la resistance a l'erythromycine etait de 48 % et 4.3 % pour les isolats humains et bovins, respectivement. Treize des isolats humains (26 %) etaient resistants a la methicilline (MRSA) tandis que tous les isolats bovins etaient sensibles. En outre 84.6 % des souches MRSA etaient egalement resistantes a 8 antimicrobiens differents. On peut en conclure qu'il n'y a pas de rapport entre les isolats humains et bovins de S.dore et le nombre de pulsotype responsable de la mammites chez la vache est limite. Les taux de resistance aux agents antimicrobiennes est inferieurs dans les isolats bovins par rapport aux isolats humains.
First Report of the Papaya Mealybug, Paracoccus marginatus (Hemiptera: Pseudococcidae), in Indonesia and India

Abstract The papaya mealybug, Paracoccus marginatus Williams and Granara de Willink (Hemiptera: Pseudococcidae), is recorded from the Oriental Region for the first time, where it was found in Indonesia (Java) and India (Tamil Nadu) in 2008. Papaya mealybug is a polyphagous pest that damages many tropical crops. A native of Central America, it spread to the Caribbean region and South America in the 1990s; since then it has been accidentally introduced to some islands in the Pacific region. The distribution, host range and characteristics of the mealybug are summarized.
Construction of a gene-data bank of tropical rainforest tree species in Sarawak, Malaysia

A “gene-data bank” of tropical rainforest tree species in Sarawak was constructed. This work was initiated to deposit DNA materials from tree species in the whole area of Sarawak and found the information gathered to be effective tools for the sustainable management of bio-resources. For this study leaf samples, mainly from dipterocarp species, were collected from eight natural populations in national parks mainly and also several man-made forests. We collected nearly 5,000 samples including 127species in 27 families. DNA extraction was done in the Forest Research Centre (FRC) in Kuching, Sarawak using a modified CTAB method. These DNA samples were deposited along with field sampling data and DNA extraction data. Genetic analysis using RAPD, AFLP, microsatellite and DNA sequencing is now under progress to clarify the genetic constitution of the tree populations. Genetic information obtained by these methods will be useful in specifying the individual trees and will be incorporated into the gene-data bank.
The population of Odonata (dragonflies) in small tropical rivers with reference to asynchronous growth patterns

Abstract The odonate larval communities in three small rivers in Penang Island were studied. More species of dragonflies were found in the Botanical Garden and Titi Teras rivers (13 and 11 respectively) of relatively similar environmental parameters. Fewer (nine) dragonfly species were collected from the Youth Park River which has a lower dissolved oxygen (DO) and a higher biological oxygen demand (BOD), conductivity and turbidity. A mixture of sand, gravel and pebble substrate of Botanical Garden River with dense growth of submerged Hydrilla, grasses and Cladias (Araceae) provided suitable habitats for the dragonflies. The sandy substrate and relatively fast flowing water of Titi Teras River was highly preferred by gomphids. In the Youth Park River, the small community of dragonfly larvae was dominated by tolerant Pseudagrion rubriceps, P. microcephalum, Orthetrum chrysis and Crocothemis servilia. Based on the larval instar distribution of Ictinogomphus decoratus and O. chrysis, very asynchronous populations of these dragonflies occurred in each river. Young larvae were continuously introduced into the populations resulting in undulating growth rate curves. The growth rates of these two species were higher in the Titi Teras River when compared to those in other rivers. Density-dependent mortality, asynchronous cannibalism and fish predation could play important roles in regulating the larval dragonfly population in these rivers.
COMPARISON OF UNDIRECTED PHYLOGENETIC TREES BASED ON SUBTREES OF FOUR EVOLUTIONARY UNITS

A method to measure how similar are two phylogenetic trees for the same collection of evolutionary units (EUs) is described. The measure does not change with changes in the direction of evolution in either of the two trees being compared, and thus it depends only on the convexity and proximity of the groups of EUs within the collection under study. It can also be used with only partially resolved phylogenetic trees. The measure is based on the idea that a group of four EUs is the smallest group for which there is more than one possible distinct undirected phylogenetic tree. For a given phylogenetic tree, the undirected subtree inherited by a group of four EUs is the tree that results when all the branches containing only EUs not in this group of four are removed. Every group of four EUs either inherits one of three distinct types of undirected phylogenetic trees, or is unresolved. Two phylogenetic trees can be com- pared on the basis of which groups of four EUs inherit the same type of undirected phylogenetic tree. The ideas can be extended to comparisons of three or more trees. (Phylogenetic trees; compatibility; subtree.)
Size-assortative nest preference in a paternal brooding blenny Rhabdoblennius ellipes (Jordan & Starks)

Field and laboratory studies were conducted to clarify the processes contributing to the size-assortative nest use by males of a paternal brooding blenny Rhabdoblennius ellipes. The use of natural and artificial nests by males in the field was highly size-assortative; males used smaller nests even when larger nests were available. Aquarium nest choice experiments without a competitive male strongly suggested that the size-assortative nest use by males is not the result of male–male competition for larger nests, but male preference for size-matched nests. Males were likely to choose nests on the basis of the nest entrance size rather than nest length and volume, suggesting that the size-assortative nest preference in this species is an adaptation to predation pressure against eggs and resident males.
The Role of the Territory in the Ecology of the Intertidal Limpet Lottia Gigantea (Gray)

The marine mollusk Lottia gigantea, a large grazing limpet of the upper intertidal zone, grazes algal film from a territory which it defends against intrusions by conspecifics and other grazers as well as the gradual encroachment of sessile organisms. The areas of the territories are correlated with the length of the resident Lottia, but for a given size of Lottia the areas vary greatly at different study sites. The thickness of the algal film charcteristic of the territory fluctuates, being greatest in spring. Experimental removal of abundant algal film from some territories in spring was followed by enlargement of these territories relative to controls. Growth rates of Lottia are positively correlated with the thickness of the algal film in their territories. The smaller limpets (1—2 cm in length) of the genus Acmaea are able to crop the algal film more closely than Lottia and will remove almost all the algal film from a territory if the territory—resident is removed. Experiments to determine whether te.
Effect of nitrogen and potassium fertilisation on vegetative growth and flowering of mature carob trees (Ceratonia siliqua): variations in leaf area index and water use indices

This work aimed to assess how potassium (K) and nitrogen (N) fertilisation may affect the use of precipitation in terms of vegetative and flowering response of 15-year-old carob trees during a 3-year experiment. A field trial was conducted in 1997, 1998 and 1999 in Algarve (Southern Portugal) in a calcareous soil. Four fertilisation treatments were tested: no fertiliser (control); 0.8 kg N/tree (N treatment); 1 kg K2O/tree (K treatment) and 0.8 kg N/tree plus 1 kg K2O/tree (NK treatment). No irrigation was applied during the experimental period. Branch length increments were measured every month throughout the growing season and inflorescence number was registered once per year. There was a strong seasonal effect on vegetative growth, since low levels of precipitation (115 mm) during October 1998–March 1999 suppressed the increment in branch length. N supplied to the trees (N and NK treatments) tended to increase water use indices in terms of vegetative growth. No response to K alone was observed in trees fertilised only with K. The number of inflorescences increased throughout the experimental period, particularly for N and NK treatments, and a reduction of the precipitation amount during April, May and June, may also enhance flowering. This knowledge could be important when making decisions concerning fertilisation under dry conditions. The results reported here indicate that tree growth (expressed as the branch growth) and flower production under dry-farming conditions, may be achieved by applying 0.8 kg of N (as ammonium nitrate) per tree during the growing season. However, N uptake and use depends on soil water availability.
MEASURING EFFICIENCY OF SOUTH AMERICAN FOREIGN EXCHANGE DERIVATIVES MARKET IN MINIMIZING CURRENCY RISK:

This paper attempts to reveal whether the foreign exchange (FX) derivatives market effectively and efficiently reduces the volatility to foreign exchange rate fiuctuations. Cross-country evidence suggests that development ofthe FXderivatives market does not boost up spot exchange rate volatility and reduces aggregate exposure to currency risk. Intraday evidence for Chile shows that activity in the forward market has not been associated with higher volatility in the exchange rate following the adoption ofa fioating exchange rate regime. The study also found no evidence that net positions of large participants in the FX derivatives market help to predict the exchange rate. These findings support the view that development of the FX derivatives market is valuable to reduce aggregate currency risk.
Distribuição e densidade do bivalve Anomalocardia brasiliana em praias do Rio Grande do Norte durante um período de pluviosidade atípica

O presente trabalho teve como objetivo avaliar a distribuicao e a densidade de Anomalocardia brasiliana em 22 km de praias da regiao oeste do Rio Grande do Norte durante e apos periodos de pluviosidade atipica relacionada com o fenomeno La Nina. Foram realizadas quatro coletas semestrais entre os meses de Abril/2009 e Outubro/2010, sendo realizados transcectos perpendiculares a linha da praia, ao longo de um gradiente espacial de distanciamento do estuario, visando coletar organismos, sedimento e dados sobre a temperatura e salinidade da agua. Nao foram constatadas diferencas significativas na densidade de A. brasiliana entre as diferentes epocas do ano, sendo que as densidades medias foram 218 ind. /m² em Abril/2009, 198 ind. /m² em Outubro/2009, 233 ind. /m² em Abril/2010 e 200 ind. /m² em Outubro/2010. Anomalocardia brasiliana apresentou um padrao de distribuicao bem definido, com sua ocorrencia restrita principalmente a regiao estuarina do rio Apodi/Mossoro onde os teores de materia orgânica do sedimento foram mais elevados. Pode-se constatar que esta especie apresentou reduzida resiliencia, uma vez que nao conseguiu retornar a sua densidade anterior a Marco/2008, ou seja, antes das chuvas intensas ocasionadas pelo fenomeno La Nina.
Responses to human-like artificial agents : effects of user and agent characteristics

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