Untersuchungen zu Fütterung, Milchleistung und Tiergesundheit von Milchkühen im Ökologischen Landbau

The breeding scheme entails yield differences of more than 2 000 kg energy corrected milk (ECM) per cow and year. On average, farms feeding less concentrate yielded slightly lower milk yields per cow and year, however, because of the longer productive life the cows showed similar milk yields over their lifetime. The farms investigated so far appeared to have healthy cows, even if fed low levels of concentrates or in the case of extremely low or high urea contents in the milk. These values could indicate the cows’ ability to compensate for short-dated changes

Kraftfuttergaben und Milchleistung bei Weidegang von Milchviehherden im ökologischen Landbau

During grazing, the efficiency of concentrate feeding on milk yields is low, especially when white clover is present in the sward (Wilkens et al., 1994). Clover in animal feed enhances forage intake; feeding trials have shown increased intake rates by 15-30 % (Paul, 2003). These results are of special interest for organic farms, where clover has a higher impact on the farming system. In the experimental organic farm of the Landwirtschaftskammer Nordrhein-Westfalen (Haus Riswick) the concentrate rate fed during grazing time showed no influence upon milk yields (2,6 resp.4,7 kg DM concentrate/ animal/day). In agreement with these results a three years investigation on 89 organic farms in Northwest Germany showed no effect of concentrate feeding on milk yield during the grazing season. Furthermore, a reduction or increase of concentrate rates during the grazing season did not show any differences in animal health so far

A Virtual Conversational Agent for Teens with Autism: Experimental Results and Design Lessons

We present the design of an online social skills development interface for teenagers with autism spectrum disorder (ASD). The interface is intended to enable private conversation practice anywhere, anytime using a web-browser. Users converse informally with a virtual agent, receiving feedback on nonverbal cues in real-time, and summary feedback. The prototype was developed in consultation with an expert UX designer, two psychologists, and a pediatrician. Using the data from 47 individuals, feedback and dialogue generation were automated using a hidden Markov model and a schema-driven dialogue manager capable of handling multi-topic conversations. We conducted a study with nine high-functioning ASD teenagers. Through a thematic analysis of post-experiment interviews, identified several key design considerations, notably: 1) Users should be fully briefed at the outset about the purpose and limitations of the system, to avoid unrealistic expectations. 2) An interface should incorporate positive acknowledgment of behavior change. 3) Realistic appearance of a virtual agent and responsiveness are important in engaging users. 4) Conversation personalization, for instance in prompting laconic users for more input and reciprocal questions, would help the teenagers engage for longer terms and increase the system's utility

Interaction of Stored, Cooled Proton Beams with Fiber Targets

This research was sponsored by the National Science Foundation Grant NSF PHY-931478

Spin Correlation Coefficients in pp-->pnpi+ from 325 to 400 MeV

The spin correlation coefficient combinations Axx + Ayy, Axx - Ayy and the analyzing powers Ay(theta) were measured for pp-->pnpi+ at beam energies of 325, 350, 375 and 400 MeV. A polarized internal atomic hydrogen target and a stored, polarized proton beam were used. These polarization observables are sensitive to contributions of higher partial waves. A comparison with recent theoretical calculations is provided.Comment: 8 Pages, 1 Table, 5 Figures. Accepted for publication in Phys. Lett.

Cross section and analyzing power of pol{p}p -> pn pi+ near threshold

The cross section and analyzing power of the pol{p}p -> pn pi+ reaction near threshold are estimated in terms of data obtained from the pol{p}p -> d pi+ and pp -> pp pi0 reactions. A simple final state interaction theory is developed which depends weakly upon the form of the pion-production operator and includes some Coulomb corrections. Within the uncertainties of the model and the input data, the approach reproduces well the measured energy dependence of the total cross section and the proton analyzing power at a fixed pion c.m. angle of 90deg, from threshold to T_p = 330 MeV. The variation of the differential cross section with pion angle is also very encouraging.Comment: 20 pages, Latex including 4 eps figure

Recoil-Ion Detection System

This research was sponsored by the National Science Foundation Grant NSF PHY-931478

Differential Cross Section and Analyzing Power of p(p,pi+)d Near Threshold

This research was sponsored by the National Science Foundation Grant NSF PHY-931478

Photofission of heavy nuclei at energies up to 4 GeV

Total photofission cross sections for 238U, 235U, 233U, 237Np, 232Th, and natPb have been measured simultaneously, using tagged photons in the energy range Egamma=0.17-3.84 GeV. This was the first experiment performed using the Photon Tagging Facility in Hall B at Jefferson Lab. Our results show that the photofission cross section for 238U relative to that for 237Np is about 80%, implying the presence of important processes that compete with fission. We also observe that the relative photofission cross sections do not depend strongly on the incident photon energy over this entire energy range. If we assume that for 237Np the photofission probability is equal to unity, we observe a significant shadowing effect starting below 1.5 GeV.Comment: 4 pages of RevTex, 6 postscript figures, Submitted to Phys. Rev. Let

Emergent global oscillations in heterogeneous excitable media: The example of pancreatic beta cells

Using the standard van der Pol-FitzHugh-Nagumo excitable medium model I demonstrate a novel generic mechanism, diversity, that provokes the emergence of global oscillations from individually quiescent elements in heterogeneous excitable media. This mechanism may be operating in the mammalian pancreas, where excitable beta cells, quiescent when isolated, are found to oscillate when coupled despite the absence of a pacemaker region.Comment: See home page http://lec.ugr.es/~julya