495 research outputs found
Analysing musical performance through functional data analysis: rhythmic structure in Schumann's Träumerei
Functional data analysis (FDA) is a relatively new branch of statistics devoted to describing and modelling data that are complete functions. Many relevant aspects of musical performance and perception can be understood and quantified as dynamic processes evolving as functions of time. In this paper, we show that FDA is a statistical methodology well suited for research into the field of quantitative musical performance analysis. To demonstrate this suitability, we consider tempo data for 28 performances of Schumann's Träumerei and analyse them by means of functional principal component analysis (one of the most powerful descriptive tools included in FDA). Specifically, we investigate the commonalities and differences between different performances regarding (expressive) timing, and we cluster similar performances together. We conclude that musical data considered as functional data reveal performance structures that might otherwise go unnoticed.Peer ReviewedPostprint (author's final draft
EcologĂa reproductiva de los olmos de ribera
This paper review our current knowledge of the reproductive ecology in the genus Ulmus, for which few investigations has been conducted and relatively little information is available. In the genus Ulmus, as in other riparian or sub-riparian genera, trees reproduce either vegetatively (by sprouting) or sexually. These mechanisms work differently. Sprouting permits colonization of open areas close to the trees, being especially frequent from large trees following death of their stem. Sprouting from the surviving roots of trees affected with Dutch Elm Disease is abundant in Spanish Ulmus minor. Sexual reproduction is infrequent, and requires some special conditions to be successful. It probably occurs coincidently with massive river floods that remove riparian vegetation and deposit a fertile muddy bed suitable for seed germination. Many Ulmus minor genotypes do not produce seed owing to seed abortion and other mechanisms. As a result, two gender-classes, male and cosexual, are presumably present in Spain, although this requires confirmation. A hypothesis trying to explain female sterility as the result of a trade-off between sexual and vegetative reproduction has been recently proposed, but it requires to be confirmed. Further research is also necessary for a better knowledge of flooding effect on elm regeneration and for evaluating other aspects of its reproductive ecology.Este artículo revisa el actual conocimiento de la ecología reproductiva en el género Ulmus, del que hay poca información disponible. Las especies del género Ulmus se reproducen, al igual que ocurre en otras especies riparias o sub-riparias, tanto sexual como vegetativamente (a través de renuevos). Estos mecanismos son efectivos en situaciones distintas. Así, los renuevos permiten la colonización de zonas abiertas próximas a los árboles, y son especialmente frecuentes tras la muerte del tronco principal de grandes árboles, como se ha observado en España, donde el rebrote a partir de raíces supervivientes de ejemplares de Ulmus minor afectados por la grafiosis es muy abundante. La reproducción sexual, por otra parte, es infrecuente, y requiere ciertas condiciones especiales para ser exitosa, teniendo lugar, probablemente, cuando se producen grandes inundaciones que eliminan la vegetación riparia y depositan una fértil capa de barro adecuada para que las semillas germinen. Gran número de genotipos de Ulmus minor no producen semilla debido a distintos mecanismos, entre los que destaca el aborto de la semilla. Como consecuencia, en España se encuentran presumiblemente dos géneros distintos de árboles en relación con sus características sexuales, masculino y cosexual, aunque esto requiere confirmación. Recientemente se ha propuesto una hipótesis que trata de explicar la presencia de esterilidad femenina como resultado de un equilibrio entre la reproducción sexual y vegetativa, pero esto requiere igualmente confirmación. También es necesario realizar nuevos estudios para conocer mejor el efecto de las inundaciones en la regeneración del olmo y para evaluar otros aspectos poco conocidos de su ecología reproductiva
Fittonia verschaffeltii Response to Artificial Light Treatments: BIOMASS, Nutrient Concentrations and Physiological Changes
The purpose of the present study was to evaluate the effects of different light treatments on biomass, nutrient concentrations and physiological parameters of Fittonia verschaffeltii (Lem) Van Houtte. The aim was to establish a methodology to evaluate the effect of photosynthetically active radiation (PAR) emitted by lamps on biomass. The light treatments used were tube luminescent Dunn (TL-D), tube luminescent Dunn + light emitting diodes (LEDs) and Tube luminescent 5 (TL-5). At the end of the experimental period, biomass, nutritional, biochemical, and physiological parameters were assessed. A clear reduction in total plant dry weight under TL-D + LEDs at the end of the experiment was recorded. With respect to nutrient concentration in the different organs assessed, there was no clear response under the different light treatments. The growth under TL-D lamps resulted in the highest concentration of total soluble sugars and starch in leaves, whereas the highest value of indole 3-acetic acid concentration was under TL-5 lamps. Plants grown under TL-D + LEDs showed the lowest values of chlorophyll a, b and a + b. The relationship proposed between integrated use of spectral energy (IUSE) and total dry weight (TDW) showed a good correlation with an R2 value of 0.86, therefore we recommend this methodology to discern the effects of the different spectral qualities on plant biomass
RC structures cyclic behavior simulation with a model integrating plasticity, damage, and bond-slip
The behavior of reinforced concrete structures under severe demands, as strong ground motions, is highly complex; this is mainly due to the complexity of concrete behavior and to the strong interaction between concrete and steel, with several coupled failure modes. On the other hand, given the increasing awareness and concern on the worldwide seismic risk, new developments have arisen in earthquake engineering; nonetheless, some developments are mainly based on simple analytical tools that are widely used, given their moderate computational cost. This research aims to provide a solid basis for validation and calibration of such developments by using computationally efficient continuum mechanics-based tools. Within this context, this paper presents a model for 3D simulation of cyclic behavior of RC structures. The model integrates a bond-slip model developed by one of the authors and the damage variable evolution methodology for concrete damage plastic model developed by some authors. In the integrated model, a new technique is derived for efficient 3D analysis of bond-slip of 2 or more crossing reinforcing bars in beam-column joints, slabs, footings, pile caps, and other similar members. The analysis is performed by implementing the bond-slip model in a user element subroutine of Abaqus and the damage variable evolution methodology in the original concrete damage plastic model in the package. Two laboratory experiments consisting of a column and a frame subjected to cyclic displacements up to failure are simulated with the proposed formulation
The courses of objective physical activity and the association with sleepiness during a 2-week-on/2-week-off offshore shift rotation:an observational repeated-measures study
BACKGROUND: Offshore workers are assumed to have poor health behaviours, but no studies have yet examined physical activity (PA) during a full offshore shift rotation period, including both work and at home periods. Furthermore, the relationship of PA with sleepiness, a prevalent safety hazard offshore, is not known. This study aimed to examine (1) the courses of objectively measured PA in offshore workers during pre-, offshore and post-offshore periods, and (2) the association between PA and self-reported sleepiness. METHODS: An observational repeated measures study was conducted among 36 offshore workers during a full 2-week on/2-week off offshore shift rotation. Objective PA was assessed using Daytime Activity Averages (DAA) from actigraph recordings. Sleepiness was assessed using next-morning Karolinska Sleepiness Scale (KSS) scores. The courses of PA over time were analysed with Linear Mixed Models (LMM). Parallel LMM were used to assess the longitudinal relationship between PA and sleepiness, both on a between-person and within-person level. RESULTS: The courses of PA were not significantly different between the pre-, offshore, and post-offshore periods. In addition, between-person trends of PA and sleepiness were not associated (p ranges between 0.08─0.99) and PA did not affect next-morning sleepiness on a within-person level (p = 0.15). CONCLUSIONS: PA levels during the offshore working period were not different from PA levels at home. Furthermore, PA was not associated with next-morning sleepiness. Further research should focus on different levels of PA including its intensity level
Nanomedicine against biofilm infections: A roadmap of challenges and limitations
Microbial biofilms are complex three-dimensional structures where sessile microbes are embedded in a polymeric extracellular matrix. Their resistance toward the host immune system as well as to a diverse range of antimicrobial treatments poses a serious health and development threat, being in the top 10 global public health threats declared by the World Health Organization. In an effort to combat biofilm-related microbial infections, several strategies have been developed to independently eliminate biofilms or to complement conventional antibiotic therapies. However, their limitations leave room for other treatment alternatives, where the application of nanotechnology to biofilm eradication has gained significant relevance in recent years. Their small size, penetration efficiency, and the design flexibility that they present makes them a promising alternative for biofilm infection treatment, although they also present set-backs. This review aims to describe the main possibilities and limitations of nanomedicine against biofilms, while covering the main aspects of biofilm formation and study, and the current therapies for biofilm treatment. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease Toxicology and Regulatory Issues in Nanomedicine > Toxicology of Nanomaterials Toxicology and Regulatory Issues in Nanomedicine > Regulatory and Policy Issues in Nanomedicine
Variance constraints strongly influenced model performance in growth mixture modeling:a simulation and empirical study
BACKGROUND: Growth Mixture Modeling (GMM) is commonly used to group individuals on their development over time, but convergence issues and impossible values are common. This can result in unreliable model estimates. Constraining variance parameters across classes or over time can solve these issues, but can also seriously bias estimates if variances differ. We aimed to determine which variance parameters can best be constrained in Growth Mixture Modeling. METHODS: To identify the variance constraints that lead to the best performance for different sample sizes, we conducted a simulation study and next verified our results with the TRacking Adolescent Individuals' Lives Survey (TRAILS) cohort. RESULTS: If variance parameters differed across classes and over time, fitting a model without constraints led to the best results. No constrained model consistently performed well. However, the model that constrained the random effect variance and residual variances across classes consistently performed very poorly. For a small sample size (N = 100) all models showed issues. In TRAILS, the same model showed substantially different results from the other models and performed poorly in terms of model fit. CONCLUSIONS: If possible, a Growth Mixture Model should be fit without any constraints on variance parameters. If not, we recommend to try different variance specifications and to not solely rely on the default model, which constrains random effect variances and residual variances across classes. The variance structure must always be reported Researchers should carefully follow the GRoLTS-Checklist when analyzing and reporting trajectory analyses
Deep Learning for Vanishing Point Detection Using an Inverse Gnomonic Projection
We present a novel approach for vanishing point detection from uncalibrated
monocular images. In contrast to state-of-the-art, we make no a priori
assumptions about the observed scene. Our method is based on a convolutional
neural network (CNN) which does not use natural images, but a Gaussian sphere
representation arising from an inverse gnomonic projection of lines detected in
an image. This allows us to rely on synthetic data for training, eliminating
the need for labelled images. Our method achieves competitive performance on
three horizon estimation benchmark datasets. We further highlight some
additional use cases for which our vanishing point detection algorithm can be
used.Comment: Accepted for publication at German Conference on Pattern Recognition
(GCPR) 2017. This research was supported by German Research Foundation DFG
within Priority Research Programme 1894 "Volunteered Geographic Information:
Interpretation, Visualisation and Social Computing
Growth and survival of cuttlefish (Sepia officinalis) of different ages fed crustaceans and fish. Effects of frozen and live prey
Three feeding experiments, using live mysid shrimp, grass shrimp or fish fry as prey for 1-, 30- and 60-day-old cuttlefish were conducted to determine the efficiency of each dietary source in relation to cuttlefish size and age. Additionally, a fourth experiment using fish fry and grass shrimp, but previously frozen, was also conducted. The results showed that when 1-day-old cuttlefish were fed mysids, grass shrimp or fish for 4 weeks, mysids were the best prey, but only during the first week. From this moment until the end of the experiment, the best growth rate was when cuttlefish were fed grass shrimp. Cuttlefish fed fish fry showed the poorest growth rate throughout the experiment. Similarly, cuttlefish aged 30 or 60 days fed grass shrimp or fish fry had the best growth rates when fed grass shrimp. When cuttlefish were fed live fish, survival increased with size of cuttlefish (73.3%, 91.7% and 100% for 1, 30 and 60 days cuttlefish, respectively). In the fourth experiment, using frozen diets, overall acceptance of each diet (feeding rates) was the same for fish and shrimp. However, lower growth was obtained when cuttlefish were fed fish compared to grass shrimp. This lower growth was due to a lower food conversion (28% vs. 41%). Since cephalopod paralarvae and juvenile most likely need prey rich in polyunsaturated fatty acids (PUFA), phospholipids and cholesterol, and a moderate content in neutral lipids, we have analyzed the biochemical compositions of the different prey to evaluate the influence of this factor on growth and survival.En prensa2,04
Fixation of bioactive compounds to the cuticle of Artemia
Artemia is extensively used in aquaculture to feed early stages of cultured marine species. A problem associated
with this practice is that Artemia fails to supply some essential nutrients. As a possible solution, we have devised
a procedure to make Artemia a vehicle for exogenous nutrients and other bioactive compounds. It consists of the
construction of chimeric proteins composed of a chitin-binding domain, which binds to the cuticle of Artemia,
and a carrier domain that conveys a functional property. As confirmatory examples, we describe the successful
fixation to Artemia's metanauplii of two hybrid proteins: a β-galactosidase from the thermophilic bacterium
Thermotoga maritima and the jellyfish green fluorescent protein (GFP), both linked to the CBM2 chitin-binding
domain from the hyperthermophilic archaeon Pyrococcus furiosus. Positive results of experiments carried out ex
vivo and in vivo show the validity of this approach. The methodology used could become a general procedure for
the attachment of different kinds of bioactive compounds, such as enzymes, hormones, antibiotics, etc., to the
cuticle of Artemia as well as other arthropods.
Statement of relevance: Our results overcome shortcomings of Artemia as a feedstock.En prensa2,04
- …