1,680 research outputs found
DISCUSSION OF FACTORS AFFECTING STRUCTURAL CHANGE IN AGRICULTURAL SUBSECTORS: IMPLICATIONS FOR RESEARCH
Industrial Organization,
Feasible US steps to strengthen NATO deterrence in the Baltics and Poland
With Russia's invasion of Ukraine, a renewed assessment of efforts by the United States and the North Atlantic Treaty Organization (NATO) to deter Russia from taking military action on NATO's eastern flank has become particularly salient. In the coming weeks, NATO leadership will meet to discuss what longer term force posture adjustments are required to create such a deterrent. This paper proposes several modest policy recommendations which will help inform the discussion and ultimately strengthen NATO's conventional deterrence postur
Interim security insights and implications from the first two months of the Russia-Ukraine war
Russia's ongoing struggles during its invasion of Ukraine have led some to suggest that the Russian military lacks the capability to credibly threaten the North Atlantic Treaty Organization (NATO) and its member states. However, narrowly focusing on Russia's tactical and operational struggles, while omitting the flawed Russian strategic decisionmaking which underpinned the invasion, is a dangerous approach. While Russia's significant losses in this war will clearly degrade its ability to conduct large scale offensive operations against NATO in the short term, it is too soon to write off the medium to long-term threat posed by Russia. Therefore, as the Russian invasion enters a new phase, it is useful to determine what lessons should and should not be derived from this conflict. In our subsequent analysis, we analyze these initial insights and provide policy recommendations for NATO to enhance its conventional capability and strengthen its ability to credibly deter future Russian aggression
Transfers between moons with escape and capture patterns via Lyapunov exponent maps
This contribution focuses on the design of low-energy transfers between
planetary moons and presents an efficient technique to compute trajectories
characterized by desirable behaviors in the vicinities of the departure and
destination bodies. The method utilizes finite-time Lyapunov exponent maps in
combination with the Moon-to-Moon Analytical Transfer (MMAT) method previously
proposed by the authors. The integration of these two components facilitates
the design of direct transfers between moons within the context of the circular
restricted three-body problem, and allows the inclusion of a variety of
trajectory patterns, such as captures, landings, transits and takeoffs, at the
two ends of a transfer. The foundations and properties of the technique are
illustrated through an application based on impulsive direct transfers between
Ganymede and Europa. However, the methodology can be employed to assist in the
design of more complex mission scenarios, such as moon tours
Factors Influencing Spatial Variability in Nitrogen Processing in Nitrogen-Saturated Soils
Nitrogen (N) saturation is an environmental concern for forests in the eastern U.S. Although several watersheds of the Fernow Experimental Forest (FEF), West Virginia exhibit symptoms of Nsaturation, many watersheds display a high degree of spatial variability in soil N processing. This study examined the effects of temperature on net N mineralization and nitrification in N-saturatedsoils from FEF, and how these effects varied between high N-processing vs. low N-processingsoils collected from two watersheds, WS3 (fertilized with [NH4]2SO4) and WS4 (untreated control). Samples of forest floor material (O2 horizon) and mineral soil (to a 5-cm depth) were taken from three subplots within each of four plots that represented the extremes of highest and lowest ratesof net N mineralization and nitrification (hereafter, high N and low N, respectively) of untreated WS4 and N-treated WS3: control/low N, control/high N, N-treated/low N, N-treated/high N. Forest floor material was analyzed for carbon (C), lignin,and N. Subsamples of mineral soil were extractedimmediately with 1 N KCl and analyzed for NH4+and NO3– to determine preincubation levels. Extracts were also analyzed for Mg, Ca, Al, and pH. To test the hypothesis that the lack of net nitrification observed in field incubations on the untreated/low N plot was the result of absence ofnitrifier populations, we characterized the bacterial community involved in N cycling by amplification of amoA genes. Remaining soil was incubated for 28 d at three temperatures (10, 20, and30°C), followed by 1 N KCl extraction and analysis for NH4+ and NO3–. Net nitrification was essentially 100% of net N mineralization for all samples combined. Nitrification rates from lab incubation sat all temperatures supported earlier observations based on field incubations. At 30°C, rates from N- t reated/high N were three times those of N-treated/low N. Highest rates were found for untreated/high N (two times greater than those of N-treated/high N), whereas untreated/low N exhibited no net nitrification. However, soils exhibitingno net nitrification tested positive for presence of nitrifying bacteria, causing us to reject our initial hypothesis. We hypothesize that nitrifier populations in such soil are being inhibited by a combination of low Ca:Al ratios in mineral soil and allelopathic interactions with mycorrhizae of ericaceous species in the herbaceous layer
Cellular Fibronectin is Induced in Ultraviolet-Exposed Human Skin and Induces IL-10 Production by Monocytes/Macrophages
CD11b+ monocytic/macrophagic cells that infiltrate human skin after in vivo ultraviolet exposure potently produce interleukin-10. We hypothesized that binding of monocyte β1 integrins to ultraviolet-induced extracellular matrix ligands, such as fibronectin, after entry of blood monocytes into the dermis, is involved in the modulation of immunoregulatory monocytic cytokines. Immunostaining of human skin and reverse transcriptase–polymerase chain reaction studies revealed that the embryonic isoform of cellular fibronectin, in which the extra domain A (EDA) segment is spliced in (EDA+ cellular fibronectin), and confers enhanced binding to β1 integrins, is newly induced and is associated with infiltrating CD11b+ cells post in vivo ultraviolet exposure. We then tested the effect of fibronectin on resting purified peripheral monocytes in vitro. We found that monocyte interleukin-10, but not interleukin-12, was significantly induced in a concentration-dependent manner by in vitro binding to cellular fibronectin (n = 6), but not plasma fibronectin. Tumor necrosis factor-α was also induced in a concentration-dependent manner, but to a lesser extent. Monoclonal antibodies to β1 integrins β-subunit (CD29) also strongly induced tumor necrosis factor-α and interleukin-10 production, but not interleukin-12. Neutralization of tumor necrosis factor-α reduced by 54% the interleukin-10 production that was induced by monocytes binding to cellular fibronectin, indicating that interleukin-10 induction is at least in part dependent upon concomitant autocrine tumor necrosis factor-α release. In conclusion, ultraviolet skin injury results in increased production and deposition of EDA+ cellular fibronectin in the papillary dermis, which may be one of the key signals capable of inducing interleukin-10 but not interleukin-12 in monocytes that infiltrate micromilieu of human skin after ultraviolet exposure
Excimer laser interaction with dentin of the human tooth
The use an excimer laser produced many unusual conical structures within the dentin of the inner part of the human tooth. By varying the frequency of the laser one can disperse the energy and cause more bleeding in laser surgery, but not destroy the cells associated with the incision. Therefore, the healing process will virtually be without scarring. Whereas, using the infrared laser the blood loss would be less, but the healing process would tend to be longer because cells are being destroyed due to the cauterization effect of the laser. The question is, are these structures produced as an interaction with the laser or are they an intrinsic part of the structure. The effects of the laser interaction upon dentin was studied, and in using electron microscopy the interaction of the excimer laser upon the tooth dentin and other various biological tissue is more clearly understood
The Effect of Substituting High Oil Corn as a Replacement for Normal Corn in Nursery Pig Diets
The objective of this study was to determine the production and monetary effects of using High Oil Corn (HOC) in a nursery phase feeding program and monitor growth performance differences through marketing. Two groups of weaned crossbred pigs (n = 293 trial 1; n = 265 trial 2) were segregated by sex and weight into small, medium and heavy groups and allotted to 12 nursery pens. Pigs received one of two dietary treatments which included; a transitional phase I diet for 7 days; a commercial corn soy based phase II diet (NCII) for 14 days and a phase III diet (NCIII) for 7 days; a HOC soy based phase II diet for 21 days and the NCIII diet for 7 days. Body weight, Average daily feed intake and Gain/Feed (G/F) ratios were measured weekly during the nursery period. Pigs were transferred to a grow/finish barn on d 28 post-weaning. Body weight, Backfat (BF) and Longissimus Muscle Area (LMA) at the 10th and last ribs were ultrasonically evaluated 4 times prior to market. Average daily gain of nursery pigs on the three-phase NC diet was greater than pigs fed the HOC two-phase diet at d 21 post-weaning (p = .0034) and 28 post-weaning (p = .0128). ADG for heavy pigs was greater (p = .0001) than that of medium and lightweight pigs and no treatment�weight group interactions were observed (p = .2043). Pigs fed the three-phase diet had greater G/F ratios than pigs fed the HOC two-phase diet at d 21 (p = .0137) and 28 (p = .0134). LEA for pigs fed the three-phase diet was greater than pigs fed the HOC two-phase diet when measured on d 28 at the 10th (p = .0565) and last rib (p = .0370). Even though pigs were fed alike in the grow-finish period, ADG of pigs fed the three-phase nursery diet was greater (p = .0106) than that of pigs fed the HOC two-phase nursery diet. There were no differences in the predicted 114 kg weight (p = .2658). However, economic differences were noted for the two treatments with the HOC two-phase diet lowering the cost of production of marketed animals. There were no treatment differences for average daily lean growth per day (p = .8611) or percentage lean of carcasses (p = .2865). The results did not support removal of the transitional phase I diet and the substitution of HOC for NC in a phase II diet fed to nursery pigs for maximal nursery growth, nor was carcass composition of pigs at marketing adversely affected
Fidelity to a behavioral intervention to improve goals of care decisions for nursing home residents with advanced dementia
Ensuring fidelity to a behavioral intervention implemented in nursing homes requires awareness of the unique considerations of this setting for research. The purpose of this manuscript is to describe the Goals of Care (GOC) cluster-randomized trial and the methods used to monitor and promote fidelity to a GOC decision aid intervention delivered in nursing homes
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