Initial Conditions for Bubble Universes

The "bubble universes" of Coleman and De Luccia play a crucial role in string cosmology. Since our own Universe is supposed to be of this kind, bubble cosmology should supply definite answers to the long-standing questions regarding cosmological initial conditions. In particular, it must explain how an initial singularity is avoided, and also how the initial conditions for Inflation were established. We argue that the simplest non-anthropic approach to these problems involves a requirement that the spatial sections defined by distinguished bubble observers should not be allowed to have arbitrarily small volumes. Casimir energy is a popular candidate for a quantum effect which can ensure this, but [because it violates energy conditions] there is a danger that it could lead to non-perturbative instabilities in string theory. We make a simple proposal for the initial conditions of a bubble universe, and show that our proposal ensures that the system is non-perturbatively stable. Thus, low-entropy conditions can be established at the beginning of a bubble universe without violating the Second Law of thermodynamics and without leading to instability in string theory. These conditions are inherited from the ambient spacetime.Comment: Further clarifications; 28 pages including three eps files. This is the final [accepted for publication] versio

Association analysis of stem rust resistance in U.S. winter wheat

Citation: Zhang D, Bowden RL, Yu J, Carver BF, Bai G (2014) Association Analysis of Stem Rust Resistance in U.S. Winter Wheat. PLoS ONE 9(7): e103747. https://doi.org/10.1371/journal.pone.0103747Stem rust has become a renewed threat to global wheat production after the emergence and spread of race TTKSK (also known as Ug99) and related races from Africa. To elucidate U.S. winter wheat resistance genes to stem rust, association mapping was conducted using a panel of 137 lines from cooperative U.S. winter wheat nurseries from 2008 and simple sequence repeat (SSR) and sequence tagged site (STS) markers across the wheat genome. Seedling infection types were evaluated in a greenhouse experiment using six U.S. stem rust races (QFCSC, QTHJC, RCRSC, RKQQC, TPMKC and TTTTF) and TTKSK, and adult plant responses to bulked U.S. races were evaluated in a field experiment. A linearization algorithm was used to convert the qualitative Stakman scale seedling infection types for quantitative analysis. Association mapping successfully detected six known stem rust seedling resistance genes in U.S. winter wheat lines with frequencies: Sr6 (12%), Sr24 (9%), Sr31 (15%), Sr36 (9%), Sr38 (19%), and Sr1RS[superscript Amigo] (8%). Adult plant resistance gene Sr2 was present in 4% of lines. SrTmp was postulated to be present in several hard winter wheat lines, but the frequency could not be accurately determined. Sr38 was the most prevalent Sr gene in both hard and soft winter wheat and was the most effective Sr gene in the adult plant field test. Resistance to TTKSK was associated with nine markers on chromosome 2B that were in linkage disequilibrium and all of the resistance was attributed to the Triticum timopheevii chromosome segment carrying Sr36. Potential novel rust resistance alleles were associated with markers Xwmc326-203 on 3BL, Xgwm160-195 and Xwmc313-225 on 4AL near Sr7, Xgwm495-182 on 4BL, Xwmc622-147 and Xgwm624-146 on 4DL, and Xgwm334-123 on 6AS near Sr8. Xwmc326-203 was associated with adult plant resistance to bulked U.S. races and Xgwm495-182 was associated with seedling resistance to TTKSK

Diversity patterns associated with varying dispersal capabilities as a function of spatial and local environmental variables in small wetlands in forested ecosystems

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. The diversity of species on a landscape is a function of the relative contribution of diversity at local sites and species turnover between sites. Diversity partitioning refers to the relative contributions of alpha (local) and beta (species turnover) diversity to gamma (regional/landscape) diversity and can be influenced by the relationship between dispersal capability as well as spatial and local environmental variables. Ecological theory predicts that variation in the distribution of organisms that are strong dispersers will be less influenced by spatial properties such as topography and connectivity of a region and more associated with the local environment. In contrast, the distribution of organisms with limited dispersal capabilities is often dictated by their limited dispersal capabilities. Small and ephemeral wetlands are centers of biodiversity in forested ecosystems. We sampled 41 small and ephemeral wetlands in forested ecosystems six times over a two-year period to determine if three different taxonomic groups differ in patterns of biodiversity on the landscape and/or demonstrate contrasting relationships with local environmental and spatial variables. We focused on aquatic macroinvertebrates (aerial active dispersers consisting predominantly of the class Insecta), amphibians (terrestrial active dispersers), and zooplankton (passive dispersers). We hypothesized that increasing active dispersal capabilities would lead to decreased beta diversity and more influence of local environmental variables on community structure with less influence of spatial variables. Our results revealed that amphibians had very high beta diversity and low alpha diversity when compared to the other two groups. Additionally, aquatic macroinvertebrate community variation was best explained by local environmental variables, whereas amphibian community variation was best explained by spatial variables. Zooplankton did not display any significant relationships to the spatial or local environmental variables that we measured. Our results suggest that amphibians may be particularly vulnerable to losses of wetland habitat in forested ecosystems as they have high beta diversity. Consequently, the loss of individual small wetlands potentially results in local extirpations of amphibian species in forested ecosystems

Inaccessible Singularities in Toral Cosmology

The familiar Bang/Crunch singularities of classical cosmology have recently been augmented by new varieties: rips, sudden singularities, and so on. These tend to be associated with final states. Here we consider an alternative possibility for the initial state: a singularity which has the novel property of being inaccessible to physically well-defined probes. These singularities arise naturally in cosmologies with toral spatial sections.Comment: 10 pages, version to appear in Classical and Quantum Gravit

Electrochemical methods in pesticides control

The state of the art of voltammetric and amperometric methods used in the study and determination of pesticides in crops, food, phytopharmaceutical products, and environmental samples is reviewed. The main structural groups of pesticides, i.e., triazines, organophosphates, organochlorides, nitrocompounds, carbamates, thiocarbamates, sulfonylureas, and bipyridinium compounds are considered with some degradation products. The advantages, drawbacks, and trends in the development of voltammetric and amperometric methods for study and determination of pesticides in these samples are discussed

Essential Oils from Apple mint (Mentha suaveolens) and Passionflower fruit (Passiflora incarnata): Studies on Cognition, Coordination, and Chemical Components.

Plant essential oils (EO) are used as perfumes, lotions and air fresheners because of their pleasant aromas, but EO also have the ability to elicit changes in mood and behavior. These activities are influenced by the mode of administration and by multiple signaling pathways. The EO aromas from organically grown apple mint (Mentha suaveolens) and passionflower fruit (Passiflora incarnata) were assessed for their effects on cognition and coordination. Participants completed two tasks designed to test working memory and bimanual task efficiency in rooms infused with apple mint, passionflower fruit or control EO. Bimanual coordination was assessed using the Intercept2 program and the Memory Span component of CogLab 2.0 was utilized as a test of working memory. Then, the EO were analyzed by GC-MS, resulting in the identification of several compounds with affinity towards olfactory receptors and neurotransmitter systems. For specific memory subtests within CogLab, EO from apple mint aided number recall, whereas passionflower fruit hindered recall of numbers and letters that sound similar. Passionflower fruit EO slightly enhanced bimanual task coordination. The results indicate that specific aromas may differentially affect task performance

Coping with climatic extremes: Dietary fat content decreased the thermal resilience of barramundi (Lates calcarifer)

Aquatic organisms, including important cultured species, are forced to contend with acute changes in water temperature as the frequency and intensity of extreme weather events worsen. Acute temperature spikes are likely to threaten aquaculture species, but dietary intervention may play an important protective role. Increasing the concentration of macronutrients, for example dietary fat content, may improve the thermal resilience of aquaculture species, however, this remains unexplored. To evaluate this hypothesis, we used two commercially available diets (20% versus 10% crude fat) to examine if dietary fat content improves the growth performance of juvenile barramundi (Lates calcarifer) while increasing their resilience to acute thermal stress. Fish were fed their assigned diets for 28-days before assessing the upper thermal tolerance (CTMAX) and the thermal sensitivity of swimming performance (UCRIT) and metabolism. We found that feeding fish a high fat diet resulted in heavier fish, but did not affect the thermal sensitivity of swimming performance or metabolism over an 18 °C temperature range (from 20 to 38 °C). Thermal tolerance was compromised in fish fed the high fat diet by 0.48 °C, showing significantly lower CTMAX. Together, these results suggest that while a high fat diet increases juvenile L. calcarifer growth, it does not benefit physiological performance across a range of relevant water temperatures and may even reduce fish tolerance of extreme water temperatures. These data may have implications for aquaculture production in a warming world, where episodic extremes of temperature are likely to become more frequent

Training Manipulations Based on Acute Heart Rate Variability Measures

Heart rate variability (HRV) is an accurate indicator of sympathetic and parasympathetic nervous system activity. The balance between these systems affects the time between heartbeats. A high variability between heartbeats is equated to a greater influence from the parasympathetic nervous system. In this state, an individual is well rested, and therefore possesses higher readiness to perform physical activity. Through the use of smartphone applications (apps), athletes and coaches can collect accurate short-term HRV readings to assess autonomic nervous system balance. These apps provide a readiness to train score that may prove beneficial in adjusting daily training loads to maximize performance. PURPOSE: The purpose of this study is to characterize the changes in lower-body strength and power before and after a 6-week strength training program while manipulating intensity based on daily HRV readiness measures in female collegiate softball athletes. METHODS: Nine female NCAA Division II Softball athletes completed the 6-week training protocol. Participants were split into an experimental group (E; n = 5; age = 20.5±0.7 yrs, height = 166.9±2.7 cm, weight = 59.9±7.6 kg), who completed the training with the intensity adjusted based off of daily HRV readiness scores, and a control group (C; n = 4; age = 20.6±0.8 yrs, height = 171.7±1.2 cm, weight = 70.7±30.3 kg), who completed the training with no changes in exercise intensity. Measures of HRV were taken prior to each training session and used to calculate readiness scores with the use of a smartphone app. Participants completed 3 strength-training sessions per week throughout the study. Lower-body strength and power measurements were assessed before and after the protocol. One-repetition maximums on the back squat (SQ) and clean (CL) exercises and maximum vertical jump (VJ) height were collected. RESULTS: Lower-body power measurements were increased in the E group (CL: 51.3 vs. 56.9 kg, p = 0.047; VJ: 40.1 vs. 44.7 cm, p = 0.037) and the C group (CL: 56.8 vs. 63.6 kg, p = 0.021; VJ: 41.6 vs. 46.2 cm, p = 0.034), following 6 weeks of strength training. No significant differences were observed in lower body strength measurements in the E group (SQ: 74 vs. 84.1kg, p = 0.21) or the C group (SQ: 75.5 vs. 86.6 kg, p = 0.2). Significant differences were found between the prescribed volume of training and the completed volume of training (25364 vs 21650 kg, p = 0.014) in the E group. No significant differences (p \u3e 0.05) were found with SQ, CL, and VJ measures between the E and C groups following 6 weeks of strength training. No significant differences (p \u3e 0.05) were found in daily HRV measures between the E and C groups. CONCLUSION: Both groups exhibited similar HRV scores throughout the 6-week training protocol. Using daily short-term HRV readings, training intensity can be reduced without leading to any differences in lower-body strength and power improvements in female collegiate softball athletes