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Ovipositional decisions in herbivorous insects may be affected by social information from conspecifics. Social facilitation of oviposition has been suggested for the onion fly Delia antiqua. In the current study, we found that D. antiqua oviposition was unequal between paired oviposition stations of equal quality and that more eggs were laid on an oviposition station baited with decoy flies than on the control. The increased oviposition toward the decoys continued over time >8 h. When decoys were placed upside down, the number of eggs laid did not differ between the decoy and control sides of oviposition stations, suggesting that social facilitation of oviposition is mediated by visual cues. Based on these findings, mechanisms of social facilitation of oviposition in D. antiqua were discussed.
Chapter 5 draws on the survey data to show how private standards are implemented in the field. It introduces three avenues through which standards may address different definitions of sustainability: to drive sustainable intensification, to shift time horizons backward, or to act as payments for social and ecosystem services. It then evaluates standards’ success by evaluating a range of production practices in each category. It shows that particularly industry-friendly standards encourage farmers to intensify their production, with moderate success, but that simultaneous decreases in input use are rarer. Improvements in practices that encourage farmers to make short-term investments for longer-term gains in terms of health or farm resilience can be observed, but often depend on outside financial support. Finally, the chapter finds very few improvements in practices that constitute long-term opportunity costs, for two reasons: one, over time many standards have lowered the stringency of their requirements for high-opportunity-cost practices such as the maintenance of permanent shade cover. Two, even when rules are binding (e.g., minimum wage laws), they are not always followed.
In this article, Si nanoparticle (NP) films were prepared by pulsed laser ablation (PLA) in the argon atmosphere of 10 Pa at room temperature under different pulse repetition rates from 1 to 40 Hz without the baffle. Different from the conventional PLA method, the substrates were placed below and parallel to the ablated plume axis. The obtained films containing NPs were characterized by scanning electron microscopy and Raman spectrometer. The experimental results under constant laser fluence demonstrate the strong dependence of the mean size and the area number density of NPs on the repetition rate. Specifically, with the increase of pulse repetition rate, the mean size of the NPs in the film first decreases and reaches its minimum at 20 Hz, and then increases after 20 Hz, and decreases again till 40 Hz. The area number density shows the contrary trend versus mean size. The in situ diagnostic results of Langmuir probe denote the ablated Si ion density increases monotonously with the increase of repetition rate, while the temperature is almost constant. Combining with the nucleation probability, the growth/aggregation duration of NPs in the “nucleation region” and the effect of the baffle, the influence of pulse repetition rate on the formation of NPs is addressed. It is found that the repetition rate impacts the growth modes of NPs (i.e., growth and aggregation). 1–20, 20–30, and 30–40 Hz, respectively, correspond to growth-, aggregation-, and growth-controlled rate ranges without the baffle; however, 1–10, 10–20, and 20–40 Hz, respectively, correspond to growth-controlled, aggregation/growth-coexisted, and aggregation-controlled rate ranges with the baffle.
The (re)insurance industry is faced with a growing risk related to the development of information technology (IT). This growth is creating an increasingly digitally interconnected world with more and more dependence being placed on IT systems to manage processes. This is generating opportunities for new insurance products and coverages to directly address the risks that companies face. However, it is also changing the risk landscape of existing classes of business within non-life insurance where there is inherent risk of loss as a result of IT events that cannot be or have not been excluded in policy wordings or are changing the risk profile of traditional risks. This risk of losses to non-cyber classes of business resulting from cyber as a peril that has not been intentionally included (often by not clearly excluding it) is defined as non-affirmative cyber risk, and the level of understanding of this issue and the cyber peril exposure from non-cyber policies varies across the market. In contract wordings, the market has remained relatively “silent” across most lines of business about potential losses resulting from IT-related events, either by not addressing the potential issue or excluding via exclusions. Some classes of business recognise the exposure by use of write-backs. Depending on the line of business, the approach will vary as to how best to turn any “silent” exposure into a known quantity either by robust exclusionary language, pricing or exposure monitoring. This paper proposes a framework to help insurance companies address the issue of non-affirmative cyber risk across their portfolios. Whilst the framework is not intended to be an all-encompassing solution to the issue, it has been developed to help those tasked with addressing the issue to be able to perform a structured analysis of the issue. Each company’s analysis will need to tailor the basis of the framework to fit their structure and underwriting procedures. Ultimately, the framework should be used to help analysts engage with management on this issue so that the risk is understood, and any risk mitigation actions can be taken if required. In the appendix, we present a worked example to illustrate how companies could implement the framework. The example is entirely fictional, is focused on non-life specialty insurance, and is intended only to help demonstrate one possible way in which to apply the framework.
The distribution of parasites within host populations and communities, and the mechanisms responsible for these patterns, are poorly understood aspects of wildlife parasitology. Here, we evaluate the influence of the average abundance of endoparasite variance, using endoparasites of lizards from the Caatinga domain (semiarid region), north-eastern Brazil. We hypothesized that, due to the high number of generalist endoparasite species, they may occur randomly throughout host populations in an aggregate pattern. In addition, we evaluated the degree to which sample variance is influenced by the average abundance of endoparasite species, patterns of co-occurrence and dominance among endoparasite species and similarities between abundance and the richness of endoparasite infracommunities in several host species. Between September 2015 and February 2016, 2141 lizards (1233 infected) from 16 species were collected from six Caatinga areas. In total, 25,687 endoparasites were collected, which belonged to 13 species including nematodes, pentastomids, cestodes, trematodes and acanthocephalans. Parasite–host associations documented here included 39 newly identified interactions. Endoparasites occurred in a typical aggregate pattern of distribution within their hosts; there was no measurable preference related to the acquisition of hosts by endoparasites. Despite the new records, endoparasites found were commonly associated with lizards in Caatinga environments, which may reflect fauna composed of generalist endoparasite species.
Here it is demonstrated how some anionic food additives commonly used in our diet, such as tartrazine (TZ), bind to DHVAR4, an antimicrobial peptide (AMP) derived from oral host defense peptides, resulting in significantly fostered toxic activity against both Gram-positive and Gram-negative bacteria, but not against mammalian cells. Biophysical studies on the DHVAR4–TZ interaction indicate that initially large, positively charged aggregates are formed, but in the presence of lipid bilayers, they rather associate with the membrane surface. In contrast to synergistic effects observed for mixed antibacterial compounds, this is a principally different mechanism, where TZ directly acts on the membrane-associated AMP promoting its biologically active helical conformation. Model vesicle studies show that compared to dye-free DHVAR4, peptide–TZ complexes are more prone to form H-bonds with the phosphate ester moiety of the bilayer head-group region resulting in more controlled bilayer fusion mechanism and concerted severe cell damage. AMPs are considered as promising compounds to combat formidable antibiotic-resistant bacterial infections; however, we know very little on their in vivo actions, especially on how they interact with other chemical agents. The current example illustrates how food dyes can modulate AMP activity, which is hoped to inspire improved therapies against microbial infections in the alimentary tract. Results also imply that the structure and function of natural AMPs could be manipulated by small compounds, which may also offer a new strategic concept for the future design of peptide-based antimicrobials.
Parasite distribution among hosts is a fundamental aspect of host–parasite interactions. Aggregated parasite distributions within and across host species are commonly reported and potentially influenced by many factors, whether host or parasite specific, or related to host–parasite encounter and compatibility. Yet, the respective role of each in observed parasite distributions are often unclear. Here, we documented the distribution of the acanthocephalan parasite Pomphorhynchus laevis sensu lato (s.l.) in two replicate fish host populations. Aggregated distributions were observed in both populations, within and across fish host species. We found a positive abundance–prevalence relationship across fish species, suggesting that resource availability (fish host biomass density) was the main driver of P. laevis s.l. distribution. This was supported by further positive associations between mean parasite load and fish biomass density. We found little evidence for intensity-dependent regulation within host (i.e. intra-host competition among co-infecting parasites). Furthermore, P. laevis s.l. infection had no detectable effect on fish condition indices, except on the body condition of female barbel (Barbus barbus). Therefore, P. laevis s.l. tended to accumulate with size/age within fish species, and with fish biomass density among fish species, with apparently negligible limitations due to intra-host intensity-dependent regulation of parasite, or to parasite-induced morbidity in fish. The relative availability of final hosts for trophic transmission thus appears to be the main driver of P. laevis s.l. distribution among fish.
In this paper, we analyse the set of all possible aggregate distributions of the sum of standard uniform random variables, a simply stated yet challenging problem in the literature of distributions with given margins. Our main results are obtained for two distinct cases. In the case of dimension two, we obtain four partial characterization results. For dimension greater than or equal to three, we obtain a full characterization of the set of aggregate distributions, which is the first complete characterization result of this type in the literature for any choice of continuous marginal distributions.
We study a Markovian agent-based model (MABM) in this paper. Each agent is endowed with a local state that changes over time as the agent interacts with its neighbours. The neighbourhood structure is given by a graph. Recently, Simon, Taylor, and Kiss  used the automorphisms of the underlying graph to generate a lumpable partition of the joint state space, ensuring Markovianness of the lumped process for binary dynamics. However, many large random graphs tend to become asymmetric, rendering the automorphism-based lumping approach ineffective as a tool of model reduction. In order to mitigate this problem, we propose a lumping method based on a notion of local symmetry, which compares only local neighbourhoods of vertices. Since local symmetry only ensures approximate lumpability, we quantify the approximation error by means of the Kullback–Leibler divergence rate between the original Markov chain and a lifted Markov chain. We prove the approximation error decreases monotonically. The connections to fibrations of graphs are also discussed.
Should we allow grave harm to befall one individual so as to prevent minor harms befalling sufficiently many other individuals? This is a question of aggregation. Can many small harms ‘add up’, so that, collectively, they morally outweigh a greater harm? The ‘Close Enough View’ supports a moderate position: aggregation is permissible when, and only when, the conflicting harms are sufficiently similar, or ‘close enough’, to each other. This paper surveys a range of formally precise interpretations of this view, and reveals some of the problems they face. It also proposes a novel interpretation which avoids these problems.
Platelet-activating factor (PAF) is a potent mediator of inflammation that plays a crucial role in atherosclerosis. The purpose of this study was to evaluate the effect of a dietary supplement containing mainly plant extracts on PAF actions and metabolism in healthy volunteers. A double-blind, placebo-controlled, 8 weeks’ duration study was performed. Healthy volunteers were randomly allocated into the supplement or the placebo group and fifty-eight of them completed the study. The supplement contained plant extracts (Aloe gel, grape juice, Polygonum cuspidatum) and vitamins. The activities of PAF metabolic enzymes: the two isoforms of acetyl-CoA:lyso-PAF acetyltransferase, cytidine 5’-diphospho-choline:1-alkyl-2-acetyl-sn-glycerol cholinephosphotransferase (PAF-cholinephosphotransferase) and platelet-activating factor–acetylhydrolase (PAF-AH) in leucocytes and lipoprotein associated phospholipase-A2 in plasma were measured along with several markers of endothelial function. Platelet aggregation against PAF, ADP and thrombin receptor activating peptide was measured in human platelet-rich plasma by light transmission aggregometry. No difference was observed on soluble vascular cell adhesion molecule-1, sP-selectin and IL-6 levels at the beginning or during the study period between the two groups. Concerning PAF metabolism enzymes’ activity, no difference was observed at baseline between the groups. PAF-AH activity was only increased in the supplement group at 4 and 8 weeks compared with baseline levels. In addition, supplement consumption led to lower platelet sensitivity against PAF and ADP compared with baseline levels. However, a trial effect was only observed when platelets were stimulated by PAF. In conclusion, supplementation with plant extracts and vitamins ameliorates platelet aggregation primarily against PAF and secondarily against ADP and affects PAF catabolism by enhancing PAF-acetylhydrolase activity in healthy subjects.
Despite being classed as an asocial species, aggregations of sea anemones can be common in abundant species. UK populations of the geographically common aggressive intertidal sea anemone Actinia equina, form clustered aggregations notwithstanding a violent nature towards neighbours and relatives. Smaller in body size, and more abundant than those found in warmer climates, little research has been undertaken to discover what factors affect body size. This study investigates whether aggregation, distance to neighbour, submergence at low tide or pH in rock pools affect body size of A. equina in their natural habitat. Populations were investigated at five sites on the Yorkshire coast during August and September 2016. A total of 562 anemones were recorded revealing that solitary anemones were significantly larger than those found in clustered aggregations. In addition, anemones found submerged in rock pools at low tide were significantly larger than those found on emergent rock, and smaller anemones were found in significantly higher pH conditions (8.5+) than larger anemones. Anemones submerged at low tide are constantly able to feed and not subject to harsh conditions such as wind exposure and temperature, hence they can achieve larger sizes. Consequently, the size of the anemones may reflect a trade-off between the benefits of aggregating in exposed environments and the costs of competition for a reduced food resource.
Inspired by a PDE–ODE system of aggregation developed in the biomathematical literature, we investigate an interacting particle system representing aggregation at the level of individuals. We prove that the empirical density of the individual converges to the solution of the PDE–ODE system.
The aggregation of the 11 residue long NACore peptide segment of α-synuclein (68-GAVVTGVTAVA-78) has been investigated using a combination of cryogenic transmission electron microscopy (cryo-TEM), small- and wide-angle X-ray scattering, and spectroscopy techniques. The aqueous peptide solubility is pH dependent, and aggregation was triggered by a pH quench from pH 11.3 to approximately pH 8 or 6, where the average peptide net charge is weakly negative (pH 8), or essentially zero (pH 6). Cryo-TEM shows the presence of long and stiff fibrillar aggregates at both pH, that are built up from β-sheets, as demonstrated by circular dichroism spectroscopy and thioflavin T fluorescence. The fibrils are crystalline, with a wide angle X-ray diffraction pattern that is consistent with a previously determined crystal structure of NACore. Of particular note is the cryo-TEM observation of small globular shaped aggregates, of the order of a few nanometers in size, adsorbed onto the surface of already formed fibrils at pH 6. The fibrillation kinetics is slow, and occurs on the time scale of days. Similarly slow kinetics is observed at both pH, but slightly slower at pH 6, even though the peptide solubility is here expected to be lower. The observation of the small globular shaped aggregates, together with the associated kinetics, could be highly relevant in relation to mechanisms of secondary nucleation and oligomer formation in amyloid systems.
The complex life cycle of Trichinella spiralis includes the migration of newborn larvae through the bloodstream to their encystment in muscle. The parasite establishes an intimate contact with the erythrocytes of the host both during the migration of the newborn larvae and when encysting, as this parasite causes intense vascularization in the muscle cell. The goal of this work was to study the effects of various concentrations of T. spiralis muscle larvae (ML) on erythrocyte membranes. The treatment was performed by incubating human erythrocytes with equal volume of different concentrations of ML for 30 minutes, with controlled agitation (37°C). The control erythrocytes (with no contact with the larvae) were incubated in the same way with an equal volume of physiological solution. To evaluate the alterations to the erythrocytes by the action of the larvae and in the respective controls, an Erythrocyte Rheometer and a Digital Image Analysis technique were used. The results indicated that when the larval concentration was higher, the aggregation and erythrocyte membrane alterations were also higher. Also, the erythrocyte deformability index and the erythrocyte elasticity increased. The values of isolated cell coefficient varied from 0.51 in the treatment with 100 larvae/ml to 0.91 in the incubation with 1000 larvae/ml. This experiment shows that T. spiralis muscle larvae affect significantly the red blood cell aggregation and the erythrocyte viscoelastic properties.
It has repeatedly been shown that properly constructed monetary aggregates based on index number theory (such as Divisia money) vastly outperform traditional measures of money (i.e. simple sum money) in empirical models. However, opponents of Divisia frequently claim that Divisia is “too complex” for little gain. And indeed, at first glance it looks as if simple sum and Divisia sum exhibit similar dynamics. In this paper, we want to build deeper understanding of how and when Divisia and simple sum differ empirically using monthly US data from 1990M1 to 2007M12. In particular, we look at how they respond differently to monetary policy shocks, which seems to be the most essential aspect of those differences from the perspective of the policy maker. We use a very rich, fairly agnostic setup that allows us to identify many potential nonlinearities, building on a smoothed local projections approach with automatic selection of the relevant interaction terms. We find, that—while the direction of change is often similar—the precise dynamics differ sharply. In particular in times of economic uncertainty, when the proper assessment of monetary policy is most relevant, those existing differences are drastically augmented.
For previously identified weakly separable blockings of goods and assets, we construct aggregates using four superlative index numbers, the Fisher, Sato-Vartia, Törnqvist, and Walsh, two non-superlative indexes, the Laspeyres and Paasche, and the atheoretical simple summation. We conduct several tests to examine how well each of these aggregates “fit” the data. These tests are how close the aggregates come to solving the revealed preference conditions for weak separability, how often each aggregate gets the direction of change correct, and how well the aggregates mimic the preference ranking from revealed preference tests. We find that, as the number of goods and assets being aggregated increases, the problems with simple summation manifest.
A monetary production model of financial firms is employed to investigate supply-side inside-money aggregation, augmented to include credit card transaction services. Inside money is a supply-side concept. Financial firms are conceived to produce monetary and credit card transaction services as outputs through financial intermediation. While credit cards provide transactions services, credit cards have never been included into measures of the money supply. The reason is accounting conventions, which do not permit adding liabilities to assets. However, index number theory measures service flows and is based on microeconomic aggregation theory, not accounting. We derive theory needed to measure the supply of the joint services of credit cards and inside money, needed to estimate the output supply function and to compute value added. The data needed for empirical implementation of our theory are available online from the Center for Financial Stability in New York City.
Bipolar disorder is a highly heritable mental illness that transmits intergeneratively. Previous studies supported that first-degree relatives (FDRs), such as parents, offspring, and siblings, of patients with bipolar disorder, had a higher risk of bipolar disorder. However, whether FDRs of bipolar patients have an increased risk of schizophrenia, major depressive disorder (MDD), autism spectrum disorder (ASD), and attention deficit hyperactivity disorder (ADHD) remains unclear.
Among the entire population in Taiwan, 87 639 patients with bipolar disorder and 188 290 FDRs of patients with bipolar disorder were identified in our study. The relative risks (RRs) of major psychiatric disorders were assessed among FDRs of patients with bipolar disorder.
FDRs of patients with bipolar disorder were more likely to have a higher risk of major psychiatric disorders, including bipolar disorder (RR 6.12, 95% confidence interval (CI) 5.95–6.30), MDD (RR 2.89, 95% CI 2.82–2.96), schizophrenia (RR 2.64, 95% CI 2.55–2.73), ADHD (RR 2.21, 95% CI 2.13–2.30), and ASD (RR 2.10, 95% CI 1.92–2.29), than the total population did. These increased risks for major psychiatric disorders were consistent across different familial kinships, such as parents, offspring, siblings, and twins. A dose-dependent relationship was also found between risk of each major psychiatric disorder and numbers of bipolar patients.
Our study was the first study to support the familial coaggregation of bipolar disorder with other major psychiatric disorders, including schizophrenia, MDD, ADHD, and ASD, in a Taiwanese (non-Caucasian) population. Given the elevated risks of major psychiatric disorders, the public health government should pay more attention to the mental health of FDRs of patients with bipolar disorder.
This chapter deals with protein aggregation, which is a key issue in biopharmaceutical processes. Several experimental techniques to characterize the aggregate size and content are presented and fundamentals on the kinetic modelling of aggregation mechanisms are provided. The impact of operating conditions on the aggregation rate is reviewed and the steps critical for aggregate formation in biopharmaceutical processes are identified. Finally, methods aiming at reducing the aggregate content are proposed. These methods focus either on improving protein stability or on removing the formed aggregates. The former can be achieved by synthesizing aggregation-resistant proteins, tuning operating conditions, or designing processes with a shorter residence time (e.g. perfusion bioreactors or counter-current chromatography). The latter method is mainly achieved by filtration and chromatography. In particular, the simulated moving bed process is shown to be very advantageous for aggregate removal with size exclusion chromatography: it allows improving productivity, decreasing eluent consumption and increasing the outlet protein concentration as compared to single-column processes.