Search results for "selection"
showing 10 items of 1940 documents
Timing of reproductive effort as an alternative mating strategy in young black grouse (Tetrao tetrix) males
2014
Seksuaalivalinta aiheuttaa yksilöiden välille kilpailua parittelukumppaneista, minkä johdosta osa yksilöistä lisääntyy toisia enemmän. Elinkiertoteorian mukaan yksilöt eivät niukkojen resurssien vuoksi pysty tehokkaasti kohdentamaan energiaa samanaikaisesti useisiin toimintoihin, kuten kasvuun, selviytymiseen ja lisääntymiseen. Ikä, suuri koko ja näyttävät seksuaaliornamentit ovat seksuaalivalinnassa menestyvän yksilön merkkejä, sillä tällaisilla yksilöillä riittää energiaa elintärkeiden toimintojen lisäksi myös lisääntymiseen. Tavallisesti ne menestyvätkin parhaiten kilpailussa parittelukumppaneista. Nuoret tai huonokuntoiset yksilöt voivat kuitenkin turvautua vaihtoehtoisiin lisääntymisst…
A hybrid MCDM approach for ranking suppliers by considering ethical factors
2016
One of the negative effects of cooperating with un-ethically behaving suppliers is that it may devastate the companies' credibility among employees, customers and the public. In this paper, a hybrid Multiple Criteria Decision Making (MCDM) approach (Disjunctive-WPM method) is proposed to resolve this limitation. The proposed methods consist of the following steps: 1. drop unethical solutions and 2. rank the remaining solutions. Therefore, the aim of this paper is the application of the DisjunctiveWPM method to supplier selection problem by adding ethical factors into the analysis. In addition, a comparative analysis to the traditional WMP method is carried out. The proposed method appears t…
Darwin i la millora genètica animal: evolució aplicada a la producció animal
2013
Darwin va reflexionar sobre la potencialitat de la selecció natural comparant-la amb els efectes que han aconseguit els éssers humans amb la selecció artifi cial. En aquest treball s’analitza com, encara que la similitud entre ambdós tipus de selecció és visible, hi ha també importants diferències. També es presenten dos exemples d’aplicacions de la teoria evolutiva: la possible importància de la selecció sexual en la introducció de peixos transgènics i la selecció de caràcters socials en el context d’una millora genètica respectuosa amb el benestar animal.
Bateman gradients from first principles
2022
In 1948, Angus Bateman presented experiments and concepts that remain influential and debated in sexual selection. The Bateman gradient relates reproductive success to mate number, and Bateman presented this as the cause of intra-masculine selection. A deeper causal level was subsequently asserted: that the ultimate cause of sex differences in Bateman gradients is the sex difference in gamete numbers, an argument that remains controversial and without mathematical backup. Here I develop models showing how asymmetry in gamete numbers alone can generate steeper Bateman gradients in males. This conclusion remains when the further asymmetry of internal fertilisation is added to the model and fe…
Single joint exercises do not provide benefits in performance and anthropometric changes in recreational bodybuilders
2020
The purpose of the present study was to compare the changes in anthropometric measures and muscle performance in users and non-users of androgenic anabolic steroids (AAS) performing resistance training (RT) programmes involving only multiple joint (MJ) exercises or a combination of MJ and single joint (SJ) exercises. Thirty recreational bodybuilders were divided into 4 groups: non-AAS users performing only MJ exercises (MJ), non-AAS users performing MJ + SJ (MJ + SJ), AAS users performing only MJ exercises (AAS − MJ) and AAS users performing MJ + SJ exercises (AAS − MJ + SJ). Before and after 8 weeks of training, the participants were tested for 10 repetition maximum (10RM) in different RT …
Experimental study of species invasion : early population dynamics and role of disturbance in invasion success
2020
Much of our understanding of natural invasions is retrospective, based on data acquired after invaders become established. As a consequence, we know little about the characteristics of the early population growth and habitat use of the invaders during establishment. Here we report on experimental introductions of guppies into natural streams in which we conducted monthly censuses of each population. Two of the four introductions were in streams with thinned canopies, which mimics a common form of habitat disturbance. We conducted similar censuses of natural populations to characterize natural population densities and generate a null distribution against which we could test a priori hypothes…
Robust Selective Stereo SLAM without Loop Closure and Bundle Adjustment
2013
This paper presents a novel stereo SLAM framework, where a robust loop chain matching scheme for tracking keypoints is combined with an effective frame selection strategy. The proposed approach, referred to as selective SLAM (SSLAM), relies on the observation that the error in the pose estimation propagates from the uncertainty of the three-dimensional points. This is higher for distant points, corresponding to matches with low temporal flow disparity in the images. Comparative results based on the reference KITTI evaluation framework show that SSLAM is effective and can be implemented efficiently, as it does not require any loop closure or bundle adjustment.
Prototyping Crop Traits Retrieval Models for CHIME: Dimensionality Reduction Strategies Applied to PRISMA Data
2022
In preparation for new-generation imaging spectrometer missions and the accompanying unprecedented inflow of hyperspectral data, optimized models are needed to generate vegetation traits routinely. Hybrid models, combining radiative transfer models with machine learning algorithms, are preferred, however, dealing with spectral collinearity imposes an additional challenge. In this study, we analyzed two spectral dimensionality reduction methods: principal component analysis (PCA) and band ranking (BR), embedded in a hybrid workflow for the retrieval of specific leaf area (SLA), leaf area index (LAI), canopy water content (CWC), canopy chlorophyll content (CCC), the fraction of absorbed photo…
Geranium sylvaticum increases pollination probability by sexually dimorphic flowers
2022
Sexual dimorphism is expressed as different morphologies between the sexes of a species. Dimorphism is pronounced in gynodioecious populations which consist of female and hermaphrodite individuals. The small size of female flowers in gynodioecious species is often explained by resource re-allocation to seed production instead of large flowers. However, pollinator attraction is critical to female fitness, and factors other than resource savings are needed to explain the small size of female flowers. We hypothesized that the floral size dimorphism in the perennial gynodioecious Geranium sylvaticum (L.) is adaptive in terms of pollination. To test this “pollination hypothesis,” we video record…
BOTH MALE AND FEMALE SEXUAL ORNAMENTS REFLECT OFFSPRING PERFORMANCE IN A FISH
2010
Secondary sexual characters are often expressed in both sexes (mutual ornamentation), but are less often studied simultaneously. We studied the adaptive signaling function of male and female ornamentation in a mutually ornamented fish, the whitefish Coregonus lavaretus. In an experimental design in which nongenetic environmental effects were minimized, we found that highly ornamented females, males, and their parental combinations had offspring with better swimming performance and predator-avoidance ability than less ornamented individuals or combinations. Furthermore, highly ornamented females had larger offspring that also had higher yolk volume than less ornamented individuals. Offspring…