Search Results

You are looking at 1 - 10 of 20 items for

  • Author or Editor: A. Delgado x
  • Search level: All x
Clear All
Authors: , , , and

Due to the increase of the human world population, modern-day research is looking for new methods of protein exploitation. Therefore the authors conducted a joint research project with the goal to automate the breeding of Tenebrio molitor as a novel protein source. An important task is to monitor the size of larvae in order to control the rearing process. In this work, a suitable algorithm is presented to measure the size distribution of the population. It is a combination of classical image processing functions and a neural net to enhance the dataset for a more reliable result. The output can be used to determine the most efficient time for harvesting. First, a grayscale picture of the insects in one box is taken and binarised by a threshold algorithm. The connected objects in this image are separated by an irregular watershed algorithm that delivers separate segments of larvae. Not all single segments can be used for measuring the size distribution; therefore, an artificial neural network is used for a classification. In the end, the algorithm separates the segments given by the watershed and categorises them into four categories: good segments, medium segments, bad segments, and artefacts. The good segments have a recall rate of 91.4%. In the end, the identified segments can be used to establish a method for determining the size distribution and, thus, to document the growth of the larvae.

In: Journal of Insects as Food and Feed
In: Ruminant physiology

Researchers hypothesize that male loud calls play several roles in primate societies including in the context of intergroup spacing and spatial coordination. Field studies examining the behavioural correlates of vocalizations are essential to evaluate the function of these calls. This preliminary study, from July 2011 to January 2012, explores the behavioural contexts and correlates of male loud calls in a habituated group of red langurs (Presbytis rubicunda) in the Wehea Forest, East Kalimantan, Indonesia. In analysing 418 h of data collection, we find a total of 87 vocal behaviours, including bouts of multiple calls in rapid succession (i.e. calling events) and individual loud calls. In this sample, most vocal behaviour takes place in the morning with 59% of calling events occurring before 8.00 h. The mean rate of calling events is 0.12 events/h, and the mean rate of individual loud calls is 0.20 calls/h. The mean number of calling events per day is 1.31 (range: 0-4), and the mean number of individual loud calls per day is 2.81 (range: 0-13). The rate of calling events is highest in the context of intragroup conflict, followed by intergroup encounters, predator threat, group travel, and the highest number of individual loud calls occurred during intergroup encounters. Although these results are preliminary, they suggest that adult male loud calls among red langurs at Wehea may play a role in both intergroup spacing and social coordination, supporting the hypothesis that these calls can serve different functions.

In: Folia Primatologica
In: Silage production and utilisation


Separation of Tenebrio molitor larvae from unwanted residues, like frass, feed or exuviae is a key process step for an industrial scale plant. One method to separate larvae from residues is using a zigzag air classifier. For designing and for an efficient operation of a zigzag air classifier, the terminal velocity is a key parameter to separate larvae from different residues with a high separation sensitivity. In this work, the terminal velocities of different larvae sizes are evaluated analytically, numerically and experimentally. For this, the sizes of 3 week to 12 week old larvae were used to calculate and simulate the terminal velocity. To validate the results, an experiment was carried out and compared with the analytical and numerical data. For this, a model for T. molitor larvae was designed to calculate the surface and volume of a larva to produce equivalent spheres with the same physical properties as a real larva. The results are showing similar curves with terminal velocities from 5 m/s for young larvae (3 weeks old) to 12 m/s for older larvae (12 weeks old). The deviations between each method are 1 m/s for smaller larvae and 1.5 m/s for bigger larvae. In further experiments and simulations, approaches with calculation methods for non-spherical particles are necessary to achieve results closer to reality due to the cylindrical shape of T. molitor larvae.

In: Journal of Insects as Food and Feed


Food-sharing is a cooperative behaviour related to the transfer of resources between conspecifics, and it is considered a complex prosocial behaviour because of its associated costs. It is more likely that an individual cooperates with closely related kin (e.g., in food sharing), and particularly with close maternal kin. In female philopatric species, such as Cebus spp., mother–offspring bonds likely explain patterns of maternal kin biases. On the other hand, the explanation of the evolution of food-sharing among non-kin is diverse. Capuchin monkeys (genera Cebus and Sapajus) are interesting to study cooperation since this is a critical behaviour to gain and protect ecological and reproductive resources in the wild, including care of their offspring. We performed an experimental protocol to induce behavioural observations with a provisioning technique using chicken eggs in a wild group of white-faced capuchin monkeys (Cebus versicolor). We aimed to test whether this white-faced capuchin monkeys engaged in food-sharing in the wild, describing the pattern of this cooperative behaviour. Furthermore, we also described some conditions that might affect this behaviour. We observed that these capuchins shared the eggs in passive exchanges, meaning that possessors let other individuals to eat from their egg. Our results further suggest that these exchanges may be due to mainly maternal kin biases. This study offers a preliminary observation of a little-studied capuchin species in the wild and adds information about how cooperation works in the wild.

In: Behaviour

Llamas display a great variability of fibre traits that determine the quality of the fleece as raw material for textiles. Little research has been conducted on the extent of this variability, although it is important for optimal use of natural resources in the Andean region. Fibre samples of 1,869 llamas were analysed with the optical fibre diameter analyser (OFDA). The following traits were considered: Mean fibre diameter (MFD), standard deviation (SD), diameter of fine fibre (DFF), proportion of fine fibre (PFF), proportion of kemp (PK) and proportion of medullated fibre (PMF). The effects of type of llama, age, sex and coat colour were studied. The type of llama influences all traits showing that Th´ampulli (fibre type) is better than Kh´ara (meat type). With increasing age of the animal MFD, SD, DFF and PK increased whereas PFF decreased. Comparing the two sexes, females showed better fibre quality. Light coat colours tend to be of better quality than darker ones. Heritabilities and genetic correlations were estimated using animal model procedures where all information came from mother-offspring relationships. Heritability estimates were 0.33, 0.28, 0.36, 0.32 and 0.25 for MFD, SD, DFF, PFF and PK, indicating potential for genetic selection.

In: South American camelids research

Morphometric variation of biological structures has been widely used to determine taxonomic affinities among taxa, and teeth are especially informative for both deep phylogenetic relationships and specific ecological signals. We report 2-dimensional geometric morphometrics (GM) analyses of occlusal crown surfaces of lower molars (M1, n = 141; M2, n = 158) of cercopithecoid primate species. A 12-landmark configuration, including cusp tips and 8 points of the molar crown contour, were used to evaluate patterns of variation in lower molar shape among cercopithecoid primates and to predict the taxonomic attribution of 2 archaeological macaques from Roman time periods. The results showed that the lower molar shape of cercopithecoid primates reflects taxonomic affinities, mostly at a subfamily level and close to a tribe level. Thus, the cusp positions and crown contour were important elements of the pattern related to interspecific variation. Additionally, the archaeological specimens, attributed to Macaca sylvanus based on osteological information, were classified using the GM molar shape variability of the cercopithecoid primates studied. The results suggest that their molar shape resembled both M. sylvanus and M. nemestrina, and species attribution varied depending on the comparative sample used.

In: Folia Primatologica

series of push-pull chromophores built around thiophene-based . π-conjugating spacers and bearing various types of amino-donors and cyanovinyl-acceptors have been analyzed by means of UV-Vis- NIR spectroscopic measurements. Density functional theory (DFT) calculations have also been performed to help the assignment of the most relevant electronic features and to derive useful information about the molecular structure of these NLO-phores. The effects of the donor/acceptor substitution in the electronic and molecular properties of the .π -conjugated spacer have been addressed. The effectiveness of the intramolecular charge transfer (ICT) has also been tested as a function of the nature of the end groups (i.e., electron-donating or electron-withdrawing capabilities).

In: Computing Letters