To save content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about saving content to .
To save content items to your Kindle, first ensure firstname.lastname@example.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
In a previous study, we showed that access to willow fodder decreased somatic cell counts (SCC) in the milk of local Mamber goats grazing in brushland at the end of lactation. To test whether the consumption of willow affects the cells of the immune system, Alpine crossbred dairy goats grazing in the same environment were either offered free access to freshly cut willow fodder (W, n = 24) or not (C, n = 24) for 2 weeks. The willow fodder contained 7.5 g/kg DM of salicin. The other major secondary compounds were catechin, myricitrin, hyperin and chlorogenic acid (2.2, 2.6, 1.0 and 0.75 g/kg DM, respectively). Udder health status was determined before the experiment, and each of the two groups included five (W) or six (C) goats defined as infected, as established by microbial cfu in milk, and 19 (W) or 18 (C) non-infected goats. Goats ingested, on average, 600 g of DM from willow (25% of food intake), resulting in minor changes in dietary quality compared to the controls, as established by faecal near-IR spectrometry. Throughout the 2 weeks of experiment, differences between groups in dietary CP contents were minor and affected neither by infection nor by access to willow; the dietary percentage of neutral detergent fibre (NDF) decreased in C and increased in W; dietary acid detergent fibre (ADF) increased; and the dietary tannin contents decreased for both treatments. However, milking performance and milk quality attributes in both W and C goats were similar. Initial SCC and milk neutrophil (cluster of differentiation (CD)18+ and porcine granulocyte (PG)68) cell counts were higher in infected than in non-infected goats; counts decreased significantly in W but not in C uninfected goats. The percentage of CD8+ T-cells increased in all C goats, while in the W group, a significant increase was found only for infected goats. The consumption of willow mitigated an increase in CD8+ in blood and triggered an increase in CD8+ in milk, suggesting an immune-regulatory effect independent of udder status. To our knowledge, this is the first report of a direct nutraceutical effect of fodder ingestion on the immune status of goats.
J. E. Colwell, University of Central Florida Orlando, Florida, USA,
J. Blum, Technische Universität Braunschweig Braunschweig, GERMANY,
R. N. Clark, Planetary Science Institute Tucson, Arizona, USA,
S. Kempf, University of Colorado Boulder, Colorado, USA,
R. M. Nelson, Planetary Science Institute Tucson, Arizona, USA
The surface area of Saturn's rings is greater than that of any of the planets in the solar system, yet, aside from dust, we have never observed or sampled an individual ring particle. Rings are unique in the solar system in that they are a complex dynamical system whose individual constituents interact not only with the light that we use to sense them remotely, but also with each other through gravitational and contact forces. These dynamical interactions play as large a role in determining the appearance of the ring system as do the optical properties of the individual ring particles. In this chapter we review the experimental work that has been done to help us understand both aspects of planetary rings: their collective dynamical behavior and their optical properties.
We have a wealth of data on the behavior of ensembles of particles, both dynamically and their optical properties. Laboratory measurements of the behavior of various likely ring particle analogs are a critical link in connecting these bulk observations with the nature of individual ring particles, and understanding the properties of individual ring particles should provide clues to the outstanding unanswered questions about the age and origin of rings.
Images of Saturn's rings and optical depth profiles from occultations show features at a variety of spatial scales, from the resolution limit of tens of meters for occultations up to thousands of kilometers, and including most scales in between (Colwell et al., 2009; Chapter 3). A frustratingly small fraction of these structures is well understood. Many that remain puzzling, such as the large optical depth fluctuations in Saturn's central B ring, the complex structure in the B ring and the inner A ring, the long-wavelength low-amplitude undulations in optical depth in the C ring, and the plateaus in the C ring, are likely linked to either the collective behavior of the ring particles governed in part by their collisional properties (see e.g. Schmidt et al., 2009, for a review) or by ballistic transport of material due to extrinsic micrometeoroid bombardment (Chapter 9). The mechanical properties of individual ring particles are critical in both types of process.
On August 25, 2017, Hurricane Harvey made landfall near Corpus Christi, Texas. The ensuing unprecedented flooding throughout the Texas coastal region affected millions of individuals.1 The statewide response in Texas included the sheltering of thousands of individuals at considerable distances from their homes. The Dallas area established large-scale general population sheltering as the number of evacuees to the area began to amass. Historically, the Dallas area is one familiar with “mega-sheltering,” beginning with the response to Hurricane Katrina in 2005.2 Through continued efforts and development, the Dallas area had been readying a plan for the largest general population shelter in Texas. (Disaster Med Public Health Preparedness. 2019;13:33–37)
The United States of America (USA) has the largest international population of any nation in the world. Immigrants from Latin American countries, where intestinal parasites are endemic, comprise more than half of this population. This study aims to determine the prevalence of strongyloidiasis, a potentially deadly parasitic infection, in foreign-born individuals. We conducted a cross-sectional study in Washington, DC, to determine the seroprevalence of Strongyloides stercoralis infection using an NIE-ELISA IgG antibody assay. Multi-parallel quantitative real-time polymerase chain reaction (qPCR) was performed in stool samples of NIE-ELISA-positive patients to investigate possible polyparasitism. The NIE-ELISA assay detected an S. stercoralis prevalence of 4.2% in a group of 119 volunteers. Combining NIE-ELISA and qPCR detected a parasite prevalence of 5.0%. Our results underscore the relevance of systematic testing for gastrointestinal parasites in individuals from endemic regions. It also makes a case for a survey in the USA to identify immigrants' risk for strongyloidiasis and other gastrointestinal parasitic infections.
Ecological restoration of trees is often constrained by limited knowledge of the biology, propagation and management requirements of individual species. Consequently, restoration initiatives rarely incorporate less well-known species or those that are difficult to source and grow. We describe challenges associated with the restoration of threatened trees in the Araucaria Forest of southern Brazil, and analyse the effectiveness of methods used to define target species, identify seed sources and generate information on the phenology of rare or threatened tree species. A review of secondary data identified 71 rare or threatened taxa as targets for seed collection. We then surveyed 68.7 km of trails in 26 forest remnants, identifying and mapping 1,027 seed-producing trees of 38 species. Surveys confirmed the scarcity of several tree species (including seven species with an abundance of <0.04 individuals per km), and nine species showed no signs of fruiting during 3 years of phenological monitoring. These findings, together with limited knowledge and application of optimal seed collection methods, are significant factors impeding the recovery of these species within their natural habitat. Wider application of the results of this case study could support restoration of the Araucaria Forest with seedlings from a wider diversity of species.
We present a comprehensive survey of various computational methods in CEDRES++ (Couplage Equilibre Diffusion Résistive pour l'Etude des Scénarios) for finding equilibria of toroidal plasma. Our focus is on free-boundary plasma equilibria, where either poloidal field coil currents or the temporal evolution of voltages in poloidal field circuit systems are given data. Centered around a piecewise linear finite element representation of the poloidal flux map, our approach allows in large parts the use of established numerical schemes. The coupling of a finite element method and a boundary element method gives consistent numerical solutions for equilibrium problems in unbounded domains. We formulate a new Newton method for the discretized nonlinear problem to tackle the various nonlinearities, including the free plasma boundary. The Newton method guarantees fast convergence and is the main building block for the inverse equilibrium problems that we can handle in CEDRES++ as well. The inverse problems aim at finding either poloidal field coil currents that ensure a desired shape and position of the plasma or at finding the evolution of the voltages in the poloidal field circuit systems that ensure a prescribed evolution of the plasma shape and position. We provide equilibrium simulations for the tokamaks ITER and WEST to illustrate the performance of CEDRES++ and its application areas.
In view of the complexity of thin-film solar cells, which are comprised of a multitude of layers, interfaces, surfaces, elements, impurities, etc., it is crucial to characterize and understand the chemical and electronic structure of these components. Because of the high complexity of the Cu2ZnSn(S,Se)4 compound semiconductor absorber material alone, this is particularly true for kesterite-based devices. Hence, this paper reviews our recent progress in the characterization of Cu2ZnSnS4 (CZTS) thin films. It is demonstrated that a combination of different soft x-ray spectroscopies is an extraordinarily powerful method for illuminating the chemical and electronic material characteristics from many different perspectives, ultimately resulting in a comprehensive picture of these properties. The focus of the article will be on secondary impurity phases, electronic structure, native oxidation, and the CZTS surface composition.
The aim of our present study was to examine the regulation of xenobiotic- and antioxidant enzymes by phytogenic feed additives in the intestine and the liver of broilers. A total of 240 male Ross-308 broiler chickens (1 d old) were fed a commercial starter diet for 2 weeks. On day 15, the birds were assigned to six treatment groups of forty birds each. The control (Con) group was fed a diet without any additive for 3 weeks. The diet of group sulforaphane (SFN) contained broccoli extract providing 0·075 g/kg SFN, whereas the diets of the other four groups contained 0·15 g/kg essential oils from turmeric (Cuo), oregano (Oo), thyme and rosemary (Ro). Weight gain and feed conversion were slightly impaired by Cuo and Oo. In the jejunum SFN, Cuo and Ro increased the expression of xenobiotic enzymes (epoxide hydrolases 1 and 2 and aflatoxin B1 aldehyde reductase) and of the antioxidant enzyme haeme oxygenase regulated by an ‘antioxidant response element’ (ARE) compared to group Con. In contrast to our expectations in the liver, the expression of these enzymes was decreased by all the additives. Nevertheless, all the additives increased the Trolox equivalent antioxidant capacity of the jejunum and the liver and reduced Fe-induced lipid peroxidation in the liver. We conclude that the up-regulation of ARE genes in the small intestine reduces oxidative stress in the organism and represents a novel mechanism by which phytogenic feed additives improve the health of farm animals.
Modern time-domain surveys have demonstrated that finding variable objects is relatively straightforward. The problem now is one of selecting and following up discoveries. With even larger-scale surveys on the horizon, the magnitude of the problem will inevitably increase. One way to prepare for the coming deluge is to have realistic estimates of the numbers of potential detections so that resources can be developed to meet that need. To that end, astronomers at the National Optical Astronomy Observatory (NOAO) have begun a project to characterize the variable sky in terms of type of objects, distribution on the sky and range of variation.
We sought to determine attitudes toward patients with borderline personality disorder (BPD) among mental health clinicians at nine academic centers in the United States.
A self-report questionnaire was distributed to 706 mental health clinicians, including psychiatrists, psychiatry residents, social workers, nurses, and psychologists.
The study showed that most clinicians consider BPD a valid diagnosis, although nearly half reported that they preferred to avoid these patients. The clinician's occupational subgroup was significantly related to attitude. Staff nurses had the lowest self-ratings on overall caring attitudes, while social workers had the highest. Social workers and psychiatrists had the highest ratings on treatment optimism. Social workers and psychologists were most optimistic about psychotherapy effectiveness, while psychiatrists were most optimistic about medication effectiveness. Staff nurses had the lowest self-ratings on empathy toward patients with BPD and treatment optimism.
Negative attitudes persist among clinicians toward BPD, but differ among occupational subgroups. Overall, caring attitudes, empathy, and treatment optimism were all higher among care providers who had cared for a greater number of BPD patients in the past 12 months.
These findings hold important implications for clinician education and coordination of care for patients with BPD.
The composition of Cu2ZnSnS4 thin-film solar cell absorbers was varied to induce the.formation of secondary impurity phases. For their identification, the samples have been investigated by Cu L3 and S L2,3 soft x-ray absorption (XAS) spectroscopy. We find that Cu L3 XAS is especially sensitive to the presence of copper sulfides as well as copper oxides and/or changes in the electron configuration, suggesting a basis for future studies of the surface, defect, and interface characterization of similar samples. Additionally, it is shown that the S L2,3 absorption data can be used as a very sensitive probe of the variations in the prevalence of S-Zn bonds in the near-surface region of the investigated samples.
Understanding local perceptions of disease causation could help public health officials improve strategies to prevent bloody diarrhoea. A cross-sectional survey was conducted in Dhaka, Bangladesh to elicit community beliefs about the causes of and prevention strategies for bloody diarrhoea. Between March and June 2003, we interviewed 541 randomly selected respondents. Overall, 507 (93%) respondents perceived that a vaccine could prevent bloody diarrhoea. If a vaccine provided lifetime protection, 445 (83%) respondents stated that they would opt to get the vaccine and would pay a median of $0·05 (range U.S.$0·01–0·15) for it, equivalent to <1% of their median weekly income. There was almost universal perception that an effective vaccine to prevent bloody diarrhoea was highly beneficial and acceptable. While respondents valued a vaccine for prevention of bloody diarrhoea, they were only willing to pay minimally for it. Therefore, achieving a high rate of Shigella vaccine coverage may require subsidy of vaccine purchase.
Monthly bacteriological water testing of traditional water sources (ponds, rivers, unprotected springs and traditional wells) used by five villages in northeastern Imo State, Nigeria, was conducted during the period January 1983 to August 1985. The membrane-filtration technique was used to detect faecal coliforms (FC) and faecal streptococci (FS). Evidence of faecal pollution was seen throughout the year for all water sources. During the study period, the monthly geometric mean counts per 100 ml of water (all sources combined) ranged from 760 to 17877 for FC and from 678 to 17394 for FS. The peak period of faecal pollution occurred during the transition between the dry and wet seasons and in the early wet season. During this peak pollution season (February–May), the geometric mean counts were 2·5–7·2 times higher than in the remaining part of the year for all source types except rivers, with ponds being the most heavily polluted. Preliminary findings on the sensitivity and specificity, in this tropical environment, of the standard membrane-filtration technique for enumerating FC are presented. The implications of the findings of this study for the environmental control of waterborne and hygiene-related diseases are discussed.
Inflammation is a stereotypical physiological response to infections and tissue injury; it initiates pathogen killing as well as tissue repair processes and helps to restore homeostasis at infected or damaged sites. Acute inflammatory reactions are usually self-limiting and resolve rapidly, due to the involvement of negative feedback mechanisms. Thus, regulated inflammatory responses are essential to remain healthy and maintain homeostasis. However, inflammatory responses that fail to regulate themselves can become chronic and contribute to the perpetuation and progression of disease. Characteristics typical of chronic inflammatory responses underlying the pathophysiology of several disorders include loss of barrier function, responsiveness to a normally benign stimulus, infiltration of inflammatory cells into compartments where they are not normally found in such high numbers, and overproduction of oxidants, cytokines, chemokines, eicosanoids and matrix metalloproteinases. The levels of these mediators amplify the inflammatory response, are destructive and contribute to the clinical symptoms. Various dietary components including long chain ω-3 fatty acids, antioxidant vitamins, plant flavonoids, prebiotics and probiotics have the potential to modulate predisposition to chronic inflammatory conditions and may have a role in their therapy. These components act through a variety of mechanisms including decreasing inflammatory mediator production through effects on cell signaling and gene expression (ω-3 fatty acids, vitamin E, plant flavonoids), reducing the production of damaging oxidants (vitamin E and other antioxidants), and promoting gut barrier function and anti-inflammatory responses (prebiotics and probiotics). However, in general really strong evidence of benefit to human health through anti-inflammatory actions is lacking for most of these dietary components. Thus, further studies addressing efficacy in humans linked to studies providing greater understanding of the mechanisms of action involved are required.
This article is intended to be used as an introduction to the problem of protoplanetary dust aggregation. The basic concept of dust aggregation and its description by Smoluchowski's equation are presented. Analytic solutions to Smoluchowski's equation are explored which show some characteristics of the more general solutions, such as self-similarity and scaling behavior. The physics of dust aggregation is treated through interaction forces between the particles and empirical data on sticking efficiencies and particle morphologies in dust-dust collisions. Aggregate morphologies are described by the fractal concept, and its implications for collision cross sections and collision velocities are discussed. Theoretical and experimental work on collision-induced restructuring and fragmentation of fractal and non-fractal dust aggregates is presented. Finally, the latest modelling approaches for protoplanetary dust growth are discussed.