Comparison of echogram measurements against data expectations and assumptions for distinguishing seafloor substrates

Defining types of seafloor substrate and relating them to the distribution of fish and invertebrates is an important but difficult goal. An examination of the processing steps of a commercial acoustics analyzing software program, as well as the data values produced by the proprietary first echo measurements, revealed potential benef its and drawbacks for distinguishing acoustically distinct seafloor substrates. The positive aspects were convenient processing steps such as gain adjustment, accurate bottom picking, ease of bad data exclusion, and the ability to average across successive pings in order to increase the signal-to-noise ratio. A noteworthy drawback with the processing was the potential for accidental inclusion of a second echo as if it were part of the first echo. Detailed examination of the echogram measurements quantified the amount of collinearity, revealed the lack of standardization (subtraction of mean, division by standard deviation) before principal components analysis (PCA), and showed correlations of individual echogram measurements with depth and seafloor slope. Despite the facility of the software, these previously unknown processing pitfalls and echogram measurement characteristics may have created data artifacts that generated user-derived substrate classifications, rather than actual seafloor substrate types.

Age- or length-based methods of growth estimation. What drives the choice?

Based upon a global comparison of over 400 fisheries, the Principal Components Analysis (PCA) methodology was used to identify factors affecting the choice of growth estimation methods. Of the six factors examined, the growth rate (K) and asymptotic length (L8) explained most of the variations. Financial resources, i.e., Gross National Product (GNP), and latitude were also important factors.

Estudo de níveis de ozônio troposférico usando métodos de estatística univariada e multivariada para duas localidades da cidade do Rio de Janeiro

Com cada vez mais intenso desenvolvimento urbano e industrial, atualmente um desafio fundamental é eliminar ou reduzir o impacto causado pelas emissões de poluentes para a atmosfera. No ano de 2012, o Rio de Janeiro sediou a Rio +20, a Conferência das Nações Unidas sobre Desenvolvimento Sustentável, onde representantes de todo o mundo participaram. Na época, entre outros assuntos foram discutidos a economia verde e o desenvolvimento sustentável. O O3 troposférico apresenta-se como uma variável extremamente importante devido ao seu forte impacto ambiental, e conhecer o comportamento dos parâmetros que afetam a qualidade do ar de uma região, é útil para prever cenários. A química das ciências atmosféricas e meteorologia são altamente não lineares e, assim, as previsões de parâmetros de qualidade do ar são difíceis de serem determinadas. A qualidade do ar depende de emissões, de meteorologia e topografia. Os dados observados foram o dióxido de nitrogênio (NO2), monóxido de nitrogênio (NO), óxidos de nitrogênio (NOx), monóxido de carbono (CO), ozônio (O3), velocidade escalar vento (VEV), radiação solar global (RSG), temperatura (TEM), umidade relativa (UR) e foram coletados através da estação móvel de monitoramento da Secretaria do Meio Ambiente (SMAC) do Rio de Janeiro em dois locais na área metropolitana, na Pontifícia Universidade Católica (PUC-Rio) e na Universidade do Estado do Rio de Janeiro (UERJ) no ano de 2011 e 2012. Este estudo teve três objetivos: (1) analisar o comportamento das variáveis, utilizando o método de análise de componentes principais (PCA) de análise exploratória, (2) propor previsões de níveis de O3 a partir de poluentes primários e de fatores meteorológicos, comparando a eficácia dos métodos não lineares, como as redes neurais artificiais (ANN) e regressão por máquina de vetor de suporte (SVM-R), a partir de poluentes primários e de fatores meteorológicos e, finalmente, (3) realizar método de classificação de dados usando a classificação por máquina de vetor suporte (SVM-C). A técnica PCA mostrou que, para conjunto de dados da PUC as variáveis NO, NOx e VEV obtiveram um impacto maior sobre a concentração de O3 e o conjunto de dados da UERJ teve a TEM e a RSG como as variáveis mais importantes. Os resultados das técnicas de regressão não linear ANN e SVM obtidos foram muito próximos e aceitáveis para o conjunto de dados da UERJ apresentando coeficiente de determinação (R2) para a validação, 0,9122 e 0,9152 e Raiz Quadrada do Erro Médio Quadrático (RMECV) 7,66 e 7,85, respectivamente. Quanto aos conjuntos de dados PUC e PUC+UERJ, ambas as técnicas, obtiveram resultados menos satisfatórios. Para estes conjuntos de dados, a SVM mostrou resultados ligeiramente superiores, e PCA, SVM e ANN demonstraram sua robustez apresentando-se como ferramentas úteis para a compreensão, classificação e previsão de cenários da qualidade do ar

Análise de componentes principais aplicada a ruído eletroquímico

Neste trabalho foi utilizado um método matemático para classificar registros de potencial e corrente de ensaios de corrosão na técnica de amperimetria de resistência nula (ZRA). Foi aplicado o método estatístico de múltiplas variáveis simples chamado Análise dos Componentes Principais (PCA), cujo objetivo principal foi identificar padrões nestes dados de ruído eletroquímico. Foram testados o aço carbono UNS G10200, os aços inoxidáveis austenítico UNS S31600 e o superduplex UNS S32750 em meios de ácido sulfúrico (5% H2SO4), cloreto férrico (0,1 mol/L FeCl3) e hidróxido de sódio (0,1% NaOH). Os ensaios foram replicados com oito repetições para se ter reprodutibilidade e conhecimento dos aspectos estatísticos envolvidos. Os resultados mostraram que a análise de componentes principais pode ser utilizada como uma ferramenta para analisar sinais de ruído eletroquímico, identificando os clusters dos comportamentos potencial-tempo, corrente-tempo e acessoriamente identificar os outliersdos registros temporais.

Mandibular morphometric variation among Chinese cercopithecoids and the unique structure of the snub-nosed monkey (Rhinopithecus) mandible

In order to understand how mandibular structure differs among the Chinese cercopithecoids (Rhinopithecus, Trachypithecus and Macaca), particularly the uniqueness of the snub-nosed monkeys (Rhinopithecus), we analysed ten mandibular measurements by principal components analysis (PCA), and examined scaling patterns. The results provided by the PCA illustrated differences due to size among the cercopithecoids and the relationship between colobines (Trachypithecus and Rhinopithecus) and cercopithecines, in which macaques (Macaca) are included. Allometric analysis indicated that, biomechanically, there is not a marked difference between macaques and leaf-eating monkeys. This may be associated with the fact that both share some similar ecology and niches in south and southwest China. The snub-nosed monkeys exhibit a significantly more robust mandible, evident in the symphysis, corpus, condyle, and masticatory momentum arm. This supports the hypothesis, based on the study of dental structure, that Rhinopithecus is a unique group in Asian Old World monkeys (OWMs) and has developed some unique characteristics in order to adapt to the tough food available in the severe cold climate of the Plateaux of Qinghai-Tibet, Yun-Gui and Qingling in China.

黄土丘陵沟壑区纸坊沟小流域农业生态安全态势变化的驱动力分析

以黄土丘陵沟壑区纸坊沟小流域为研究对象,利用1985—2006年调查和监测资料,综合现有研究成果,将主成分分析和通径分析方法相结合,分析可能影响农业生态安全态势变化的各因子,探讨农业生态安全态势变化的驱动力。结果表明:自然条件是影响黄土丘陵沟壑区纸坊沟小流域农业生态安全态势变化的基础,人文社会经济条件是其变化的主要驱动力,具体可归纳为经济发展、人口压力、流域产业结构调整和农业科技进步4类因子;此外,国家和区域的相关政策、农业产业链与资源量相关度对农业生态安全也有一定影响。

荞麦(Fagopyrum tataricum Gaertn.和F. esculentum Moench.)对紫外线B辐射的响应研究

近二十多年来，基于对臭氧层衰减、紫外线B（UV-B）增强的担心，研究者希望了解到紫外线辐射对不同作物的影响情况，增强UV-B辐射条件下是否对作物的生长发育、产量质量构成威胁。在本试验中，我们首先探讨了双子叶作物黄瓜（Cucumis sativus）和大豆（Glycine max）对不同紫外波段的生物效应[分别为B-UVA（315-400 nm），N-UVA（315-340 nm），B-UVB（275-400 nm）和N-UVB（290-340 nm），UV-（>400nm）作对照]。我们观察到所有的UV波段处理都使黄瓜和大豆的生长受到抑制，并且细胞受到不同程度的氧化伤害；UV波段处理的作用效果与不同波段的紫外有效生物辐射剂量有关。处理差异在UV-B波段内部和UV-A波段内部同样存在。植物生长UV辐射公式（BSWF）能很好的预测本试验UV-B波段内的平均植物效应，但不能预测UV-A波段的植物效应。短波UV-A的生物作用强于长波UV-A。光合色素的变化与UV波谱差异和种间差异有关。在高的紫外/可见光背景下，UV-A处理同UV-B同样导致光合色素的降低，但黄瓜类胡萝卜素/叶绿素比例升高。与其他研究者的试验结果比较后，我们认为紫外线B辐射的生物效应一致性很高，但紫外线A波段的生物学效应存在较大争议。因此我们在本试验的基础上仅进行荞麦[苦荞(Fagopyrum tataricum Gaertn.)和甜荞(Fagopyrum esculentum Moench.)]对紫外线B波段的响应研究。 我们对苦荞品种-圆籽荞进行了连续两个生长季节的大田半控制试验以观察UV-B辐射对苦荞生长、发育、产量及叶片色素的影响；试验小区进行降低UV-B、近充足UV-B和增强UV-B辐射处理。我们的试验表明在不同强度UV-B辐射下苦荞的生长、地上部生物量积累及最终产量都有所下降，但苦荞的发育加快；当前条件下的日光紫外线B辐射对植物生长和产量也造成负面影响。植物光合色素被日光及增强UV-B辐射降低；UV化合物及卢丁含量在中低剂量的UV-B辐射强度下显著升高，但在高剂量的增强UV-B辐射下短期升高后迅速下降。我们的试验表明苦荞是一个对UV-B高度敏感的作物。苦荞对UV-B的敏感性与UV-B剂量、外界环境因素及生长季节有关。 单个苦荞品种的试验结果使我们认识到外界UV-B辐射已经对苦荞生长发育构成逆境条件，未来全球气候变化条件下增强紫外线B辐射可能使其处于更不利的生长环境中。因此我们有进行了多个种群进行UV-B响应观察并筛选耐性种群。我们对15个苦荞种群进行增强UV-B辐射处理（6.30 kJ m2 UV-BBE，模拟当地25%的臭氧衰减），我们观察苦荞UV-B辐射效应存在显著的种内差异，UV-B辐射对多数种群具有抑制作用，但对一些种群还有刺激作用。我们采用主成分分析方法与作物UV-B响应指数（RI）来评价苦荞作物UV-B辐射耐性。我们发现作物的UV-B耐性不仅与其原产地背景UV-B强度有关，而且与作物相对生长效率、次生代谢产物含量（如卢丁）及其他因素有关。我们观察到苦荞伸展叶总叶绿素变化与UV-B耐性成正相关；室内苦荞幼苗的UV-B辐射致死试验表明：苦荞种群死亡率与其UV-B耐性成负相关。 此外，我们对甜荞的UV-B辐射响应也进行了初步研究。选取美姑甜荞、巧家甜荞和云龙甜荞进行5个梯度的增强UV-B辐射室外模拟试验。我们观察到UV-B辐射显著降低了甜荞的生长、生物量及产量；并严重影响了甜荞的生殖生长，降低了花序数、种子数和结实率；并且UV-B辐射对甜荞的抑制作用存在显著的剂量效应。三种甜荞品种存在显著的种内差异，其中美姑品种UV-B耐性最强，且膜脂受UV-B辐射氧化伤害最小，这与该品种UV-B辐射下较高的GR酶活性、APX酶活性和PPO酶活性、以及含量更高的抗坏血酸有关。甜荞的次生代谢也受到增强UV-B辐射的影响，其香豆酰类化合物在UV-B辐射下升高显著，而槲皮素含量也在高剂量UV-B辐射下有所增加；卢丁含量依赖UV-B辐射剂量而变化，中低剂量UV-B辐射下其卢丁含量逐渐升高，但在高剂量辐射下逐渐下降。 通过对生长在高海拔地区的荞麦作物(苦荞和甜荞)进行的室外研究，我们认识到作物不同品种存在很大的耐性差异，这就为UV-B耐性育种创造了有利条件。进一步加大荞麦种质资源筛选力度并深入认识荞麦抗性机理，在此基础上通过杂交或其他基因融合手段培育抗性品种，对高剂量UV-B辐射地区的荞麦产量的提高将起到重要推动作用，并使荞麦生产能有效应对未来全球气候变化条件下UV-B辐射可能升高的威胁。 During last few decades, due to concern of ozone layer depletion and enhancement of ultraviolet B radiation（UV-B, 280-315 nm), the agronomist want to know the responses of different crop species to UV-B. In the first experiment of our study, the effect of different UV band [B-UVA（315-400 nm), N-UVA（315-340 nm), B-UVB（275-400 nm), N-UVB（290-340 nm）and UV-（>400nm, as control)] on the cucumber（Cucumis sativus）and soybean（Glycine max）were investigated in growth room. Spectra-dependent differences in growth and oxidation indices existed within UV-A bands as well as UV-B bands. The general biological effects of different band were UV- ＜ B-UVA＜ N-UVA＜N-UVB＜B-UVB. The plant growth biologically spectra weighting function（BSWF）matched well with average plant response in UV-B region, but not in UV-A region. Shorter UV-A wavelength imposed more negative impact than longer UV-A wavelength did in both species. The effect on photosynthetic pigment was related to different UV bands and different species. The photosynthetic pigment content was decreased by UV-A spectra as well as UV-B spectra. In comparison with the results of previous studies, we found that the wavelength-dependent biological effect of ultraviolet B radiation has high consistency, but the biological effect of ultraviolet-A radiation was inconsistent. We narrow our following study on the effect of ultraviolet B radiation on the buckwheat（tartary buckwheat and common buckwheat). The tartary buckwheat（Fagopyrum tataricum Gaertn.）cultivars Yuanziqiao was grown in the sheltered field plots for two consecutive seasons under reduced, near-ambient and two supplemental levels of UV-B radiation. The crop growth, photosynthetic pigments, total biomass, final seed yield and thousand-grain weight were decreased by near-ambient and enhanced UV-B radiation, while crop development was promoted by enhanced UV-B radiation. Leaf rutin concentration and UV-B absorbing compound was generally increased by UV-B with the exception of 8.50 kJ m-2 day-1 supplemental levels. Our results showed that tartary buckwheat is a potentially UV-B sensitive species. Study on one cultivars showed that ambient solar radiation had present a stress to tartary buckwheat. This makes it necessary to observe the UV-B response of many cultivars and screen tolerant cultivars. Fifteen populations of tartary buckwheat were experienced enhanced UV-B radiation simulating 25% depletion of the stratospheric ozone layer in Kunming region, and plant responses in growth, morphology and productivity were observed. Principal components analysis（PCA）was used to evaluate overall sensitivity of plant response to UV-B as well as response index. The different populations exhibited significant differences in responses to UV-B. The photosynthetic pigments of young seedlings were also affected significantly under field condition. On the other hand, the healthy seedlings of different populations were exposed to the high level of UV-B radiation in growth chambers to determine the plant lethality rate. The plant tolerance evaluated by multivariate analysis was positively related to total plant chlorophyll change, but negatively related to lethality rate. In other hand, the UV-B responses of the other important cultivated buckwheat species, common buckwheat（Fagopyrum esculentum Moench.), were also studied preliminarily. Three widespread cultivated variety（Meigu, Qiaojia and Yunlong cultivars）were provided with five level of enhanced UV-B radiation outdoors. We observed that the crop growth, development and production were significantly decreased, and reproductive production, like anthotaxy number, seed number and seed setting ratio, was also decreased. Dose-dependent inhibition effect caused by enhanced UV-B radiation also existed in common buckwheat. Significant intraspecific difference existed in those three cultivars. The Meigu cultivars with dwarfed growth and lower production have highest UV-B tolerance as well as lowest damage in cell membrane, this could be associated with profound enhancements of glutathione reductase（GR）activity, ascorbate peroxidase activity and polyphenol oxidase activity as well as higher ascorbic acid concentration. The secondary metabolism was also affected by UV-B radiation, with profound elevation of coumarin compound and moderate increase of quercetin concentration. Rutin concentration was peaked in 5kJ m-2 UV-B. The contrasting effect of UV-B radiation on different populations indicated that there existed abundant genetic resources for selecting tolerant populations of common and tartary buckwheat. Much effort needed be pose on screening of buckwheat germplasm and clarification of mechanism of buckwheat tolerance to UV-B. On this base the tolerant cultivars could be bred by hybridization and other gene transfusion method, this would help increase buckwheat yield in high ambient UV-B region and counteract the effect of possible enhanced UV-B radiation in future.

Is perception of upper body orientation based on the inertia tensor? Normogravity versus microgravity conditions

During lateral leg raising, a synergistic inclination of the supporting leg and trunk in the opposite direction to the leg movement is performed in order to preserve equilibrium. As first hypothesized by Pagano and Turvey (J Exp Psychol Hum Percept Perform, 1995, 21:1070-1087), the perception of limb orientation could be based on the orientation of the limb's inertia tensor. The purpose of this study was thus to explore whether the final upper body orientation (trunk inclination relative to vertical) depends on changes in the trunk inertia tensor. We imposed a loading condition, with total mass of 4 kg added to the subject's trunk in either a symmetrical or asymmetrical configuration. This changed the orientation of the trunk inertia tensor while keeping the total trunk mass constant. In order to separate any effects of the inertia tensor from the effects of gravitational torque, the experiment was carried out in normo- and microgravity. The results indicated that in normogravity the same final upper body orientation was maintained irrespective of the loading condition. In microgravity, regardless of loading conditions the same (but different from the normogravity) orientation of the upper body was achieved through different joint organizations: two joints (the hip and ankle joints of the supporting leg) in the asymmetrical loading condition, and one (hip) in the symmetrical loading condition. In order to determine whether the different orientations of the inertia tensor were perceived during the movement, the interjoint coordination was quantified by performing a principal components analysis (PCA) on the supporting and moving hips and on the supporting ankle joints. It was expected that different loading conditions would modify the principal component of the PCA. In normogravity, asymmetrical loading decreased the coupling between joints, while in microgravity a strong coupling was preserved whatever the loading condition. It was concluded that the trunk inertia tensor did not play a role during the lateral leg raising task because in spite of the absence of gravitational torque the final upper body orientation and the interjoint coupling were not influenced.

Effects of Undaria pinnatifida, Himanthalia elongata and Porphyra umbilicalis extracts on in vitro α-glucosidase activity and glucose diffusion

Background: Seaweeds are good sources of dietary fibre, which can influence glucose uptake and glycemic control.Objective: To investigate and compare the in vitro inhibitory activity of different extracts from Undaria pinnatifida (Wakame), Himanthalia elongata (Sea spaghetti) and Porphyra umbilicalis (Nori) on α-glucosidase activity and glucose diffusion.Methods: The in vitro effects chloroform-, ethanol- and water-soluble extracts of the three algae were assayed on α- glucosidase activity and glucose diffusion through membrane. Principal Components Analysis (PCA) was applied to identify patterns in the data and to discriminate which extract will show the most proper effect.Results: Only water extracts of Sea spaghetti possessed significant in vitro inhibitory effects on α-glucosidase activity (26.2% less mmol/L glucose production than control, p < 0.05) at 75 min. PCA distinguished Sea spaghetti effects, supporting that soluble fibre and polyphenols were involved. After 6 h, Ethanol-Sea spaghetti and water-Wakame extracts exerted the highest inhibitory effects on glucose diffusion (65.0% and 60.2% vs control, respectively). This extracts displayed the lowest slopes for glucose diffusion-time lineal adjustments (68.2% and 62.8% vs control, respectively).Conclusions: The seaweed hypoglycemic effects appear multi-faceted and not necessarily concatenated. According to present results, ethanol and water extracts of Sea spaghetti, and water extracts of Wakame could be useful for the development of functional foods with specific hypoglycemic properties.

A unified view on the effect of fibers and loading on sfrc creep through linear projection to latent structures

Creep of Steel Fiber Reinforced Concrete (SFRC) under flexural loads in the cracked state and to what extent different factors determine creep behaviour are quite understudied topics within the general field of SFRC mechanical properties. A series of prismatic specimens have been produced and subjected to sustained flexural loads. The effect of a number of variables (fiber length and slenderness, fiber content, and concrete compressive strength) has been studied in a comprehensive fashion. Twelve response variables (creep parameters measured at different times) have been retained as descriptive of flexural creep behaviour. Multivariate techniques have been used: the experimental results have been projected to their latent structure by means of Principal Components Analysis (PCA), so that all the information has been reduced to a set of three latent variables. They have been related to the variables considered and statistical significance of their effects on creep behaviour has been assessed. The result is a unified view on the effects of the different variables considered upon creep behaviour: fiber content and fiber slenderness have been detected to clearly modify the effect that load ratio has on flexural creep behaviour.

Larval habitat associations with human land uses, roads, rivers, and land cover for Anopheles albimanus, A. pseudopunctipennis, and A. punctimacula (Diptera: Culicidae) in coastal and highland Ecuador

Larval habitat for three highland Anopheles species: Anopheles albimanus Wiedemann, Anopheles pseudopunctipennis Theobald, and Anopheles punctimacula Dyar and Knab was related to human land uses, rivers, roads, and remotely sensed land cover classifications in the western Ecuadorian Andes. Of the five commonly observed human land uses, cattle pasture (n = 30) provided potentially suitable habitat for A. punctimacula and A. albimanus in less than 14% of sites, and was related in a principal components analysis (PCA) to the presence of macrophyte vegetation, greater surface area, clarity, and algae cover. Empty lots (n = 30) were related in the PCA to incident sunlight and provided potential habitat for A. pseudopunctipennis and A. albimanus in less than 14% of sites. The other land uses surveyed (banana, sugarcane, and mixed tree plantations; n = 28, 21, 25, respectively) provided very little standing water that could potentially be used for larval habitat. River edges and eddies (n = 41) were associated with greater clarity, depth, temperature, and algae cover, which provide potentially suitable habitat for A. albimanus in 58% of sites and A. pseudopunctipennis in 29% of sites. Road-associated water bodies (n = 38) provided potential habitat for A. punctimacula in 44% of sites and A. albimanus in 26% of sites surveyed. Species collection localities were compared to land cover classifications using Geographic Information Systems software. All three mosquito species were associated more often with the category “closed/open broadleaved evergreen and/or semi-deciduous forests” than expected (P ≤ 0.01 in all cases), given such a habitat’s abundance. This study provides evidence that specific human land uses create habitat for potential malaria vectors in highland regions of the Andes.

Studies on nitrifying microorganisms in Cochin Estuary and adjacent coastal waters

This thesis entitled “Studies on Nitrifying Microorganisms in Cochin Estuary and Adjacent Coastal Waters” reports for the first time the spatial andtemporal variations in the abundance and activity of nitrifiers (Ammonia oxidizingbacteria-AOB; Nitrite oxidizing bacteria- NOB and Ammonia oxidizing archaea-AOA) from the Cochin Estuary (CE), a monsoon driven, nutrient rich tropicalestuary along the southwest coast of India. To fulfil the above objectives, field observations were carried out for aperiod of one year (2011) in the CE. Surface (1 m below surface) and near-bottomwater samples were collected from four locations (stations 1 to 3 in estuary and 4 in coastal region), covering pre-monsoon, monsoon and post-monsoon seasons. Station 1 is a low saline station (salinity range 0-10) with high freshwater influx While stations 2 and 3 are intermediately saline stations (salinity ranges 10-25). Station 4 is located ~20 km away from station 3 with least influence of fresh water and is considered as high saline (salinity range 25- 35) station. Ambient physicochemical parameters like temperature, pH, salinity, dissolved oxygen (DO), Ammonium, nitrite, nitrate, phosphate and silicate of surface and bottom waters were measured using standard techniques. Abundance of Eubacteria, total Archaea and ammonia and nitrite oxidizing bacteria (AOB and NOB) were quantified using Fluorescent in situ Hybridization (FISH) with oligonucleotide probes labeled withCy3. Community structure of AOB and AOA was studied using PCR Denaturing Gradient Gel Electrophoresis (DGGE) technique. PCR products were cloned and sequenced to determine approximate phylogenetic affiliations. Nitrification rate in the water samples were analyzed using chemical NaClO3 (inhibitor of nitrite oxidation), and ATU (inhibitor of ammonium oxidation). Contribution of AOA and AOB in ammonia oxidation process was measured based on the recovered ammonia oxidation rate. The contribution of AOB and AOA were analyzed after inhibiting the activities of AOB and AOA separately using specific protein inhibitors. To understand the factors influencing or controlling nitrification, various statistical tools were used viz. Karl Pearson’s correlation (to find out the relationship between environmental parameters, bacterial abundance and activity), three-way ANOVA (to find out the significant variation between observations), Canonical Discriminant Analysis (CDA) (for the discrimination of stations based on observations), Multivariate statistics, Principal components analysis (PCA) and Step up multiple regression model (SMRM) (First order interaction effects were applied to determine the significantly contributing biological and environmental parameters to the numerical abundance of nitrifiers). In the CE, nitrification is modulated by the complex interplay between different nitrifiers and environmental variables which in turn is dictated by various hydrodynamic characteristics like fresh water discharge and seawater influx brought in by river water discharge and flushing. AOB in the CE are more adapted to varying environmental conditions compared to AOA though the diversity of AOA is higher than AOB. The abundance and seasonality of AOB and NOB is influenced by the concentration of ammonia in the water column. AOB are the major players in modulating ammonia oxidation process in the water column of CE. The distribution pattern and seasonality of AOB and NOB in the CE suggest that these organisms coexist, and are responsible for modulating the entire nitrification process in the estuary. This process is fuelled by the cross feeding among different nitrifiers, which in turn is dictated by nutrient levels especially ammonia. Though nitrification modulates the increasing anthropogenic ammonia concentration the anthropogenic inputs have to be controlled to prevent eutrophication and associated environmental changes.

Comparing methods for dimensionality reduction when data are density functions

Functional Data Analysis (FDA) deals with samples where a whole function is observed for each individual. A particular case of FDA is when the observed functions are density functions, that are also an example of infinite dimensional compositional data. In this work we compare several methods for dimensionality reduction for this particular type of data: functional principal components analysis (PCA) with or without a previous data transformation and multidimensional scaling (MDS) for diferent inter-densities distances, one of them taking into account the compositional nature of density functions. The difeerent methods are applied to both artificial and real data (households income distributions)

Building the niche through time: using 13,000 years of data to predict the effects of climate change on three tree species in Europe

Aim  Species distribution models (SDMs) based on current species ranges underestimate the potential distribution when projected in time and/or space. A multi-temporal model calibration approach has been suggested as an alternative, and we evaluate this using 13,000 years of data. Location  Europe. Methods  We used fossil-based records of presence for Picea abies, Abies alba and Fagus sylvatica and six climatic variables for the period 13,000 to 1000 yr bp. To measure the contribution of each 1000-year time step to the total niche of each species (the niche measured by pooling all the data), we employed a principal components analysis (PCA) calibrated with data over the entire range of possible climates. Then we projected both the total niche and the partial niches from single time frames into the PCA space, and tested if the partial niches were more similar to the total niche than random. Using an ensemble forecasting approach, we calibrated SDMs for each time frame and for the pooled database. We projected each model to current climate and evaluated the results against current pollen data. We also projected all models into the future. Results  Niche similarity between the partial and the total-SDMs was almost always statistically significant and increased through time. SDMs calibrated from single time frames gave different results when projected to current climate, providing evidence of a change in the species realized niches through time. Moreover, they predicted limited climate suitability when compared with the total-SDMs. The same results were obtained when projected to future climates. Main conclusions  The realized climatic niche of species differed for current and future climates when SDMs were calibrated considering different past climates. Building the niche as an ensemble through time represents a way forward to a better understanding of a species' range and its ecology in a changing climate.

Investigation of the postcure reaction and surface energy of epoxy resins using time-of-flight secondary ion mass spectrometry and contact-angle measurements

Time-of-flight secondary ion mass spectrometry (ToF-SIMS) was used to investigate correlations between the molecular changes and postcuring reaction on the surface of a diglycidyl ether of bisphenol A and diglycidylether of bisphenol F based epoxy resin cured with two different amine-based hardeners. The aim of this work was to present a proof of concept that ToF-SIMS has the ability to provide information regarding the reaction steps, path, and mechanism for organic reactions in general and for epoxy resin curing and postcuring reactions in particular. Contact-angle measurements were taken for the cured and postcured epoxy resins to correlate changes in the surface energy with the molecular structure of the surface. Principal components analysis (PCA) of the ToFSIMS positive spectra explained the variance in the molecular information, which was related to the resin curing and postcuring reactions with different hardeners and to the surface energy values. The first principal component captured information related to the chemical phenomena of the curing reaction path, branching, and network density based on changes in the relative ion density of the aliphatic hydrocarbon and the C₇H₇O⁺ positive ions. The second principal component captured information related to the difference in the surface energy, which was correlated to the difference in the relative intensity of the C_xH_yN_z⁺ ions of the samples. PCA of the negative spectra provided insight into the extent of consumption of the hardener molecules in the curing and postcuring reactions of both systems based on the relative ion intensity of the nitrogen-containing negative ions and showed molecular correlations with the sample surface energy.