More Than Eggs – Relationship Between Productivity and Learning in Laying Hens

The intense selection of chickens for production traits, such as egg laying, is thought to cause undesirable side effects and changes in behavior. Trade-offs resulting from energy expenditure in productivity may influence other traits: in order to sustain energetic costs for high egg production, energy expenditure may be redirected away from specific behavioral traits. For example, such energetic trade-offs may change the hens’ cognitive abilities. Therefore, we hypothesized highly productive laying hens to show reduced learning performance in comparison to moderate productive lines. We examined the learning ability of four chicken lines that differed in laying performance (200 versus 300 eggs/year) and phylogenetic origin (brown/white layer; respectively, within performance). In total 61 hens were tested in semi-automated Skinner boxes in a three-phase learning paradigm (initial learning, reversal learning, extinction). To measure the hens’ learning performance within each phase, we compared the number of active decisions needed to fulfill a learning criteria (80% correct choices for learning, 70% no responses at extinction) using linear models. Differences between the proportions of hens per line that reached criterion on each phase of the learning tasks were analyzed by using a Kaplan–Meier (KM) survival analysis. A greater proportion of high productive hens achieved the learning criteria on each phase compared to less productive hens (Chi23 = 8.25, p = 0.041). Furthermore, high productive hens accomplished the learning criteria after fewer active decisions in the initial phase (p = 0.012) and in extinction (p = 0.004) compared to the less selected lines. Phylogenetic origin was associated with differences in learning in extinction. Our results contradict our hypothesis and indicate that the selection for productivity traits has led to changes in learning behavior and the high productive laying hens possessed a better learning strategy compared to moderate productive hens in a feeding-rewarding context. This better performance may be a response to constraints resulting from high selection as it may enable these hens to efficiently acquire additional energy resources. Underlying mechanisms for this may be directly related to differences in neuronal structure or indirectly to foraging strategies and changes in personality traits such as fearfulness and sociality

Model study of adsorbed metallic quantum dots: Na on Cu(111)

We model electronic properties of the second monolayer Na adatom islands (quantum dots) on the Cu(111) surface covered homogeneously by the first Na monolayer. An axially-symmetric three-dimensional jellium model, taking into account the effects due to the first Na monolayer and the Cu substrate, has been developed. The electronic structure is solved within the local-density approximation of the density-functional theory using a real-space multigrid method. The model enables the study of systems consisting of thousands of Na-atoms. The results for the local density of states are compared with differential conductance ($dI/dV$) spectra and constant current topographs from Scanning Tunneling Microscopy.Comment: 10 pages, 8 figures. For better quality figures, download http://www.fyslab.hut.fi/~tto/cylart1.pd

Die elektronische Struktur adsorbierter Azabenzole auf Metalloberflaechen

SIGLETIB Hannover: DR 5278 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Angle-resolved photoemission from cytosine adsorbed on Cu (110)

Angle-resolved photoemission with synchrotron radiation has been applied to the study of adsorbed films of cytosine on Cu(110). Using dipole selection rules, we established that in the monolayer the molecules adsorb with the molecular plane perpendicular to the surface while in multilayer films only a preferred, but indeterminate, orientation was ascertainable. The oxygen lone-pair orbital was found to be strongly affected by the adsorption in the monolayer

The electronic structure of benzene adsorbed on Ag(111) studied by angle resolved photoemission

Angle resolved photoemission spectroscopy using synchrotron radiation has been applied to study a (3 × 3) overlayer of benzene adsorbed on Ag(111). This monolayer is formed by flat lying benzene molecules. The photoelectron spectra can only be interpreted if the surface molecule is described by C3v,σd symmetry. The adsorbed benzene molecules exhibit an almost uniform relaxation shift of the ionization potentials of 0.8 eV comparing adsorbed and gaseous phase. Combining the photoemission and LEED results a structural model is proposed, in which the benzene molecules occupy the three-fold hollow sites of the Ag(111) surface

Computer-aided continuous drug infusion: Setup and test of a mobile closed-loop system for the continuous automated infusion of insulin

For a diabetes mellitus patient, tight control of glucose level is essential. Results are reported of an investigation of the suitability of existing wearable continuous insulin infusors controlled and adjusted by a control algorithm using continuous glucose measurements as input to perform the functionality of an artificial pancreas. Special attention was given to the development of a continuous glucose monitor and to evaluate which quality of input data is necessary for the control algorithm. In clinical trials, it was found that for patients in a controlled environment an autonomously regulating control algorithm leads to an improved adjustment of patient glucose values and less overall insulin infusion as compared with the best fixed preprogrammed insulin infusion profiles of standard pump therapy. For the limited number of cases studied here, functionality of the control algorithm could tolerate some delay between the actual glucose values in the patient interstitial fluid and the algorithm input of up to 30 min. A quasicontinuous glucose measurement delivering Actual glucose values every 5-10 min seems to be suited to control an artificial pancreas

Orientation and electronic structure of pyrazine adsorbed on Ag(111)

Near-edge X-ray absorption fine structure (NEXAFS) and angle-resolved photoemission spectra from ordered pyrazine layers with thicknesses ranging from submonolayer to multilayer coverages on Ag(111) have been measured using synchrotron radiation. LEED reveals a (2×2) ordered adsorbate structure. The polarization dependence of the NEXAFS shows on orientation of the pyrazine molecular plane parallel to the metal surface. The angular dependence of the photoemission corroborates this result. Furthermore, a complete mapping of the valence bands and an improved symmetry assignment of the bands emerges. Substrate-induced changes in the pyrazine molecular orbital (MO) structure for the first layer can be identified in a similar way to the pyridine/Ag (111) system