THE ECONOMIC IMPACTS OF ALTERNATIVE MANURE MANAGEMENT REGULATIONS ON HOG FARMS IN THE HEARTLAND: AN INDIVIDUAL-FARM ANALYSIS

A whole-farm modeling approach applied to survey data was used to assess the economic impacts on Heartland hog farms of alternative manure management regulations on manure application. Results showed differential economic impacts on the hog operations. Many large farms (over 2,500 hogs) had to lease additional land to meet restrictions on manure phosphorous application, with reductions in net crop returns exceeding those of medium size operations (750-2,500 hogs). Feeding hogs a phytase diet to lessen phosphorous in manure reduced the additional land needed and moderated the increase in manure application costs, but net crop returns still dropped for most operations.Livestock Production/Industries,

The Effect of Vascularization and Tissue Type on Cryosurgical Procedures

Cryosurgery is a minimally-invasive surgical procedure that is used in the treatment of multiple types of cancer. Although cryosurgical treatments, which involve the application of extreme cold to diseased or cancerous tissue, are often used in the treatment of near-surface skin cancer, they have also been used to treat several other types of internal cancers, including those in the prostate, liver, and kidney. Although fundamentally similar, many of these tissues differ significantly in properties such as density, vascularization, and thermal conductivity. A major issue in cryosurgery is adapting the procedure to different tissue types. In this study, the effect of tissue perfusivity on the outcomes of cryosurgery was modeled using the COMSOL software. For the purposes of comparison, the properties of lung tissue, which is highly perfused and not as conductive, and liver tissue, which is mildly perfused and more conductive, were used. The procedure was modeled as a 10 mm diameter cryoprobe set at a temperature of -196?C in a cylindrical region of tissue 8 cm in height and 8 cm in diameter. The time required for a 26mm diameter spherical tumor to reach -45?C was determined in four scenarios, lung tissue and liver tissue both with and without blood perfusion. Although metabolic heat generation was also included, sensitivity analysis showed it to be a minor factor in the cooling process. Results showed blood perfusivity to have a significant effect on freezing time in lung tissue and a relatively minor one in liver tissue: although the addition of perfusion caused freezing time in the liver to increase from 200 to 250 seconds, the addition of perfusion in the lung tissue caused the freezing front to never reach the tumor edge. Sensitivity analyses also revealed the freezing process to be highly sensitive to conductivity as well. It was therefore concluded that although blood perfusion is one of the most important heat transfer processes in cryosurgery, tissue conductivity is just as, if not more important. We recommend that cryosurgery continue to be used as a treatment for liver tumors, but further studies are needed to determine its efficacy in highly perfused, porous tissue such as the lung

A genetic variant of the sperm-specific SLO3 K+ channel has altered pH and Ca2+ sensitivities

To fertilize an oocyte, sperm must first undergo capacitation in which the sperm plasma membrane becomes hyperpolarized via activation of potassium (K(+)) channels and resultant K(+) efflux. Sperm-specific SLO3 K(+) channels are responsible for these membrane potential changes critical for fertilization in mouse sperm, and they are only sensitive to pH i However, in human sperm, the major K(+) conductance is both Ca(2+)- and pH i -sensitive. It has been debated whether Ca(2+)-sensitive SLO1 channels substitute for human SLO3 (hSLO3) in human sperm or whether human SLO3 channels have acquired Ca(2+) sensitivity. Here we show that hSLO3 is rapidly evolving and reveal a natural structural variant with enhanced apparent Ca(2+) and pH sensitivities. This variant allele (C382R) alters an amino acid side chain at a principal interface between the intramembrane-gated pore and the cytoplasmic gating ring of the channel. Because the gating ring contains sensors to intracellular factors such as pH and Ca(2+), the effectiveness of transduction between the gating ring and the pore domain appears to be enhanced. Our results suggest that sperm-specific genes can evolve rapidly and that natural genetic variation may have led to a SLO3 variant that differs from wild type in both pH and intracellular Ca(2+) sensitivities. Whether this physiological variation confers differences in fertility among males remains to be established.info:eu-repo/semantics/publishe

Single-channel kinetics of BK (Slo1) channels

Single-channel kinetics has proven a powerful tool to reveal information about the gating mechanisms that control the opening and closing of ion channels. This introductory review focuses on the gating of large conductance Ca2+- and voltage-activated K+ (BK or Slo1) channels at the single-channel level. It starts with single-channel current records and progresses to presentation and analysis of single-channel data and the development of gating mechanisms in terms of discrete state Markov (DSM) models). The DSM models are formulated in terms of the tetrameric modular structure of BK channels, consisting of a central transmembrane pore-gate domain (PGD) attached to four surrounding transmembrane voltage sensing domains (VSD) and a large intracellular cytosolic domain (CTD), also referred to as the gating ring. The modular structure and data analysis shows that the Ca2+ and voltage dependent gating considered separately can each be approximated by 10-state two-tiered models with 5 closed states on the upper tier and 5 open states on the lower tier. The modular structure and joint Ca2+ and voltage dependent gating are consistent with a 50 state two-tiered model with 25 closed states on the upper tier and 25 open states on the lower tier. Adding an additional tier of brief closed (flicker states) to the 10-state or 50-state models improved the description of the gating. For fixed experimental conditions a channel would gate in only a subset of the potential number of states. The detected number of states and the correlations between adjacent interval durations are consistent with the tiered models. The examined models can account for the single-channel kinetics and the bursting behavior of gating. Ca2+ and voltage activate BK channels by predominantly increasing the effective opening rate of the channel with a smaller decrease in the effective closing rate. Ca2+ and depolarization thus activate by mainly destabilizing the closed states

Deployment Methods for an Origami-Inspired Rigid-Foldable Array

The purpose of this work is to evaluate several deployment methods for an origami-inspired solar array at two size scales: 25-meter array and CubeSat array. The array enables rigid panel deployment and introduces new concepts for actuating CubeSat deployables. The design for the array was inspired by the origami flasher model (Lang, 1997; Shafer, 2001). Figure 1 shows the array prototyped from Garolite and Kapton film at the CubeSat scale. Prior work demonstrated that rigid panels like solar cells could successfully be folded into the final stowed configuration without requiring the panels to flex (Zirbel, Lang, Thomson, & al., 2013). The design of the array is novel and enables efficient use of space. The array can be wrapped around the central bus of the spacecraft in the case of the large array, or can accommodate storage of a small instrument payload in the case of the CubeSat array. The radial symmetry of this array around the spacecraft is ideally suited for spacecraft that need to spin. This work focuses on several actuation methods for a one-time deployment of the array. The array is launched in its stowed configuration and it will be deployed when it is in space. Concepts for both passive and active actuation were considered

An organic nanoparticle transistor behaving as a biological synapse

Molecule-based devices are envisioned to complement silicon devices by providing new functions or already existing functions at a simpler process level and at a lower cost by virtue of their self-organization capabilities. Moreover, they are not bound to von Neuman architecture and this feature may open the way to other architectural paradigms. Neuromorphic electronics is one of them. Here we demonstrate a device made of molecules and nanoparticles, a nanoparticle organic memory filed-effect transistor (NOMFET), which exhibits the main behavior of a biological spiking synapse. Facilitating and depressing synaptic behaviors can be reproduced by the NOMFET and can be programmed. The synaptic plasticity for real time computing is evidenced and described by a simple model. These results open the way to rate coding utilization of the NOMFET in dynamical neuromorphic computing circuits.Comment: To be publsihed in Adv. Func. Mater. Revised version. One pdf file including main paper and supplementary informatio