Climate Dependent Heat Stress Mitigation Modeling for Dairy Cattle Housing

Dairy cattle are susceptible to heat stress with reported milk production loss exceeding 1.2 billion dollars in 2010. Heat stress occurs when the local thermal environment prevents adequate dissipation of metabolic heat production over extended periods. Implementing mitigation strategies in order to reduce heat stress has been a crucial need as dairy housing has transitioned from pasture to indoor housing systems. In order to maximize production, producers need the most effective cooling system to reduce heat stress. A heat stress mitigation model was developed using TMY3 data sets as inputs. The objectives of this research were to: (i) analyze the thermal environment’s ability to reduce heat stress in dairy cattle in selected regions using TMY3 data, (ii) model Holstein cattle subjected to various environmental modification systems (elevated airspeed, evaporative pad cooling, direct sprinkling) by region, (iii) create a universal barn/cooling system model to apply to selected regions with given TMY3 data inputs, and (iv) develop contour maps with optimal cooling system recommendations throughout the United States. A transient thermal balance model was developed using equations and parameters from published heat stress models in order to quantify heat dissipation from a dairy cow to her environment. The model was initially tested and evaluated using two TMY3 stations (Fresno, California SN:723890 and Eau Claire, Wisconsin SN:726435). The model’s predictions were within one standard deviation of field data. Once validated, the model was applied to all 215 TMY3 Class 1 stations and contour maps of the U.S. were created for producers to determine which cooling strategy is the most economical in their region

Learning about compact binary merger: the interplay between numerical relativity and gravitational-wave astronomy

Activities in data analysis and numerical simulation of gravitational waves have to date largely proceeded independently. In this work we study how waveforms obtained from numerical simulations could be effectively used within the data analysis effort to search for gravitational waves from black hole binaries. We propose measures to quantify the accuracy of numerical waveforms for the purpose of data analysis and study how sensitive the analysis is to errors in the waveforms. We estimate that ~100 templates (and ~10 simulations with different mass ratios) are needed to detect waves from non-spinning binary black holes with total masses in the range 100 Msun < M < 400 Msun using initial LIGO. Of course, many more simulation runs will be needed to confirm that the correct physics is captured in the numerical evolutions. From this perspective, we also discuss sources of systematic errors in numerical waveform extraction and provide order of magnitude estimates for the computational cost of simulations that could be used to estimate the cost of parameter space surveys. Finally, we discuss what information from near-future numerical simulations of compact binary systems would be most useful for enhancing the detectability of such events with contemporary gravitational wave detectors and emphasize the role of numerical simulations for the interpretation of eventual gravitational-wave observations.Comment: 19 pages, 12 figure

Large-scale Oscillation of Structure-Related DNA Sequence Features in Human Chromosome 21

Human chromosome 21 is the only chromosome in human genome that exhibits oscillation of (G+C)-content of cycle length of hundreds kilobases (500 kb near the right telomere). We aim at establishing the existence of similar periodicity in structure-related sequence features in order to relate this (G+C)% oscillation to other biological phenomena. The following quantities are shown to oscillate with the same 500kb periodicity in human chromosome 21: binding energy calculated by two sets of dinucleotide-based thermodynamic parameters, AA/TT and AAA/TTT bi-/tri-nucleotide density, 5'-TA-3' dinucleotide density, and signal for 10/11-base periodicity of AA/TT or AAA/TTT. These intrinsic quantities are related to structural features of the double helix of DNA molecules, such as base-pair binding, untwisting/unwinding, stiffness, and a putative tendency for nucleosome formation.Comment: submitted to Physical Review

A microfabricated sensor for thin dielectric layers

We describe a sensor for the measurement of thin dielectric layers capable of operation in a variety of environments. The sensor is obtained by microfabricating a capacitor with interleaved aluminum fingers, exposed to the dielectric to be measured. In particular, the device can measure thin layers of solid frozen from a liquid or gaseous medium. Sensitivity to single atomic layers is achievable in many configurations and, by utilizing fast, high sensitivity capacitance read out in a feedback system onto environmental parameters, coatings of few layers can be dynamically maintained. We discuss the design, read out and calibration of several versions of the device optimized in different ways. We specifically dwell on the case in which atomically thin solid xenon layers are grown and stabilized, in cryogenic conditions, from a liquid xenon bath

The theory of heating of the quantum ground state of trapped ions

Using a displacement operator formalism, I analyse the depopulation of the vibrational ground state of trapped ions. Two heating times, one characterizing short time behaviour, the other long time behaviour are found. The short time behaviour is analyzed both for single and multiple ions, and a formula for the relative heating rates of different modes is derived. The possibility of correction of heating via the quantum Zeno effect, and the exploitation of the suppression of heating of higher modes to reduce errors in quantum computation is considered.Comment: 9 pages, 2 figure