Short communication: Short-term intravenous amino acid infusions as a method to detect limiting amino acids in dairy cattle diets

We hypothesized that the addition of limiting AA increases dry matter intake (DMI) by reducing anaplerosis and hepatic oxidation. Accordingly, the objective of this work was to examine the effects of short-term intravenous infusions of Met, Lys, and His (which are considered the most limiting AA) on DMI as a method to detect whether specific AA are limiting in dairy cow diets. We conducted 4 experiments using Holstein cows in the immediate postpartum period to address this objective. The first experiment used 4 cows 6 to 10 d postpartum (PP) in a 4 × 4 Latin square design with 1-d periods including 12 h for infusions and 12 h for recovery. Treatments were continuous infusions of 5 (low), 10 (medium), or 15% (high) of the calculated requirement of metabolizable Met, Lys, and His or 0.9% saline (control, CONT). In the second and third experiments, 8 cows (4–12 d PP) were divided into 2 groups of 4 cows, and each group received a different diet formulated to either be low in Lys (experiment 2) or Met (experiment 3). Each experiment was a crossover design with two 1-d periods with 12-h infusions (continuous) and 12 h for recovery. Treatments were 15% of the calculated requirement of metabolizable Met, Lys, and His (high), or 0.9% saline (CONT). In the fourth experiment, 5 cows (4–14 d PP) were used in a 5 × 5 Latin square design. Periods were 2 d in which treatments were continuously infused for the first 46 h. Treatments were 0.9% saline (CONT), all (Lys, Met, and His), LM (Lys and Met), LH (Lys and His), and MH (Met and His); dosages were equal to the estimated shortage in each specific AA. In each experiment, feed intake was recorded by a computerized data acquisition system, milk yield was recorded, and milk composition was analyzed for fat, protein, lactose, and milk urea nitrogen (MUN) concentrations. Treatments did not affect DMI or yield of milk or milk components in the first experiment. In the second experiment, AA treatment increased protein percentage and reduced lactose percentage but had no effect on protein and lactose yields or DMI. In the third experiment, the AA treatment tended to increase yields of milk, lactose, and protein as well as MUN concentration but did not affect DMI. In the fourth experiment, no effects were detected for DMI and milk yield, whereas the all, LH, and LM treatments reduced milk lactose concentration compared with CONT, and MH increased MUN concentration compared with CONT and other treatments. These results failed to provide support for our hypothesis that short-term addition of these potentially limiting AA will increase DMI. This may be due to our hypothesis being inaccurate or to other factors; other limiting AA could have prevented the effects of Lys, Met, and His infusions or the infusion periods could have been too short to induce a response in DMI. Accordingly, short-term infusion of AA is probably not a sensitive method to detect limiting AA in dairy cow diets.     

Searching for close alternative plans

Consider the situation where an intelligent agent accepts as input a complete plan, i.e., a sequence of states (or operators) that should be followed in order to achieve a goal. For some reason, the given plan cannot be implemented by the agent, who then goes about trying to find an alternative plan that is as close as possible to the original. To achieve this, a search algorithm that will find similar alternative plans is required, as well as some sort of comparison function that will determine which alternative plan is closest to the original. In this paper, we define a number of distance metrics between plans, and characterize these functions and their respective attributes and advantages. We then develop a general algorithm based on best-first search that helps an agent efficiently find the most suitable alternative plan. We also propose a number of heuristics for the cost function of this best-first search algorithm. To explore the generality of our idea, we provide three different problem domains where our approach is applicable: physical roadmap path finding, the blocks world, and task scheduling. Experimental results on these various domains support the efficiency of our algorithm for finding close alternative plans. A preliminary version of this paper appeared in the International Joint Conference on Autonomous Agents and Multiagent Systems (8). An erratum to this article can be found at     

The social accident: a theoretical model and a research agenda for studying the influence of social and cultural characteristics on motor vehicle accidents

The paper develops a sociological model to explain collisions between two drivers or more. The "Social Accident" model presented here integrates empirical findings from prior studies and extant sociological theories. Sociological theory posits that social groups have unique cultural characteristics, which include a distinctive world view and ways of operating that influence its members. These cultural characteristics may cause drivers in different groups to interpret a given situation differently; therefore, they will make conflicting decisions that may possibly lead to road accidents. The proposed model may contribute to an understanding of the social mechanism related to interactions and communication among drivers by presenting new directions for understanding accidents and collisions. The paper concludes with suggestions for future research that will employ the model to assess its predictive and practical utility.     

Nonlinear Response of a Continuous Wave NMR Spectrometer for Samples with a Large Magnetization

We present a new insight in the response of a CW NMR spectrometer for highly magnetized samples above 100 MHz. The spectrometer is a bridge made of a magic T. The output of the bridge is proportional to the reflection coefficient, , of a resonant circuit, which is built with a coil containing the sample. The sensitivity of the reflection coefficient to the complex susceptibility of the sample, () = () – j(), depends on the quality factor, Q, of the circuit and filling factor, . When the condition Q 1 is not fulfilled, we show indeed that the use of a simple crystal detector, which is only sensitive to || gives rise to a strong nonlinear response of the spectrometer. Measurements of the complex value of by means of phase sensitive detection allow to recover a linear behavior. We discuss and illustrate those issues with a few circuits we designed for our measurements on liquid ³ He with spin polarizations up to 15 %. A method is described to build in a reproducible and predictable way resonant circuits matched to 50 in the frequency range 100 – 400 MHz with a quality factor as high as 1000 at 4 K.     

Absorption of Pulsed Terahertz and Optical Radiation in Earthworm Tissue and Its Heating Effect

Journal of Infrared, Millimeter, and Terahertz Waves - The transmission of THz, near-infrared (1030 nm), and green (515 nm) pulses through Eisenia andrei body wall is studied,...     

In situ HTXRD formation of magnesium titanates

Coprecipitated xerogel precursors of nanocrystalline magnesium titanates, with a Mg:Ti stoichiometric ratio of 2:1, were subjected to thermal treatment in air at constant temperature, from 100 to 1300°C, using a hot‐stage X‐ray powder diffractometer. The phase sequences, the kinetics of phase evolution and crystallite size were studied during the first hour of the process at different temperatures. Until 500°C no diffraction peaks were observed. Between 550 and 800°C the structure was a mixture of two cubic nanocrystalline coherent structures: qandilite‐like and periclase‐like forms. At 900 and 1000°C, after 15 minutes, geikielite and periclase appear in small amounts but the qandilite‐like phase remains predominant; at 1100°C and above, qandilite is formed again as a single phase. The diffraction lines were substantially broadened for all crystalline phases formed at low temperatures, becoming sharper with increasing temperature and time. The phase evolution is interpreted as a consequence of the decrease in the surface area to volume ratio with increasing temperature and time, thus decreasing the significance of the surface energy. Linear thermal expansion coefficients were derived for qandilite.     

Learning to Reason with a Restricted View

The Learning to Reason framework combines the study of Learning and Reasoning into a single task. Within it, learning is done specifically for the purpose of reasoning with the learned knowledge. Computational considerations show that this is a useful paradigm; in some cases learning and reasoning problems that are intractable when studied separately become tractable when performed as a task of Learning to Reason.In this paper we study Learning to Reason problems where the interaction with the world supplies the learner only partial information in the form of partial assignments. Several natural interpretations of partial assignments are considered and learning and reasoning algorithms using these are developed. The results presented exhibit a tradeoff between learnability, the strength of the oracles used in the interface, and the range of reasoning queries the learner is guaranteed to answer correctly.     

Should Google Scholar be used for benchmarking against the professoriate in education?

Scientometrics - In the neoliberal environment of contemporary academia, an individual’s research rankings and outputs can shape their career security and progression. When applying for...     

Heuristic search for one-to-many shortest path queries

Annals of Mathematics and Artificial Intelligence - In this paper we study the One-to-Many Shortest Path Problem (OMSPP), which is the problem of solving k shortest path problems that share the...