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Hostile Environment (hostile + environment)
Selected AbstractsHydrogels as a Platform for Stem Cell Delivery to the HeartCONGESTIVE HEART FAILURE, Issue 3 2010Mazen Kurdi PhD Stem cell therapy offers great promise to repair the injured or failing heart. The outcomes of clinical trials to date, however, have shown that the actual benefit realized falls far short of the promise. A number of factors may explain why that is the case, but poor stem cell retention and engraftment in the hostile environment of the injured heart would seem to be a major factor. Improving stem cell retention and longevity once delivered would seem a logical means to enhance their reparative function. One way to accomplish this goal may be injectable hydrogels, which would serve to fix stem cells in place while providing a sheltering environment. Hydrogels also provide a means to allow for the paracrine factors produced by encapsulated stem cells to diffuse into the injured myocardium. Alternatively, hydrogels themselves can be used for the sustained delivery of reparative factors. Here the authors discuss chitosan-based hydrogels. Congest Heart Fail. 2010;16:132,135. © 2010 Wiley Periodicals, Inc. [source] Computer-generated null models as an approach to detect perceptual range in mark,re-sight studies , an example with grasshoppersECOLOGICAL ENTOMOLOGY, Issue 2 2005Silke Hein Abstract., 1. Dispersal and habitat detection are key factors for the colonisation of habitat fragments in heterogeneous landscapes. The ability to recognise a habitat from a certain distance should increase the survival chances of a dispersing individual; however, due to methodological problems there is little information on the perceptual range of most species. 2. In a field experiment, 44 individually marked grasshoppers of the species Oedipoda caerulescens (Orthoptera: Acrididae: Locustinae) were released into an unfamiliar, hostile environment at various distances from a patch of preferred habitat. 3. Whether individuals reached the habitat or not was measured, as well as the daily movement distances. The number of individuals that reached the habitat was tested against computer-generated predictions based on different underlying rules for the movement behaviour of individuals but not accounting for the ability to detect habitat from distance. 4. On the first day a significantly higher proportion of grasshoppers arrived in the habitat than predicted by any of the null models. 5. It was concluded that individuals of O. caerulescens are able to detect their preferred habitat from a distance. 6. Edge permeability was very low as none of the individuals left the habitat once they had reached it. 7. Additional analyses showed that individuals changed movement behaviour from a directed walk with great daily distances in unsuitable habitat to a walk with significantly shorter daily distances within the preferred habitat. 8. The problems that arose in the field experiment are discussed and recommendations are given for further studies. [source] Reading, Work, and Catholic Women's BiographiesENGLISH LITERARY RENAISSANCE, Issue 3 2003Frances E. Dolan This essay considers biographies of Catholic women written after their deaths, largely by priests who served as their confessors, and the saints' lives which these biographies took as their models. The purpose of this essay is twofold: to draw attention to a significant body of Catholic writing, and to use this material to shed new light on the one text of this group that has gained considerable critical attention, The Lady Falkland, Her Life, a biography of Elizabeth Cary by one of her daughters, a Benedictine nun. Considering the Life as a participant in a subgenre of Catholic biography reveals the tension between the conventions and precedents available to Cary's biographer, on the one hand, and her intractable subject, on the other. The Life, like other similar biographies, borrows from and verges on hagiography, but is particularly unsuccessful at transforming its subject into a saint. While criticism of Cary and her works continues to dwell on her as eccentric and exceptional, determined by the particularities of her own character and experience, she is as like other female subjects of Catholic biography and hagiography as she is unlike them. This can only be seen by attending to the kinds of texts that Cary and her daughter might well have read, and the parameters they set for writing an eminent Catholic woman's life. These texts figure reading and housework as the chief means by which Catholic women define and sustain their confessional identities in the hostile environment of post-reformation England. [source] Enhanced process monitoring for wastewater treatment systemsENVIRONMETRICS, Issue 6 2008Chang Kyoo Yoo Abstract Wastewater treatment plants (WWTPs) remain notorious for poor data quality and sensor reliability problems due to the hostile environment, missing data problems and more. Many sensors in WWTP are prone to malfunctions in harsh environments. If a WWTP contains any redundancy between sensors, monitoring methods with sensor reconstruction such as the proposed one can yield a better monitoring efficiency than without a reconstruction scheme. An enhanced robust process monitoring method combined with a sensor reconstruction scheme to tackle the sensor failure problems is proposed for biological wastewater treatment systems. The proposed method is applied to a single reactor for high activity ammonia removal over nitrite (SHARON) process. It shows robust monitoring performance in the presence of sensor faults and produces few false alarms. Moreover, it enables us to keep the monitoring system running in the case of sensor failures. This guaranteed continuity of the monitoring scheme is a necessary development in view of real-time applications in full-scale WWTPs. Copyright © 2007 John Wiley & Sons, Ltd. [source] Pasteurella multocida pathogenesis: 125 years after PasteurFEMS MICROBIOLOGY LETTERS, Issue 1 2006Marina Harper Abstract Pasteurella multocida was first shown to be the causative agent of fowl cholera by Louis Pasteur in 1881. Since then, this Gram-negative bacterium has been identified as the causative agent of many other economically important diseases in a wide range of hosts. The mechanisms by which these bacteria can invade the mucosa, evade innate immunity and cause systemic disease are slowly being elucidated. Key virulence factors identified to date include capsule and lipopolysaccharide. The capsule is clearly involved in bacterial avoidance of phagocytosis and resistance to complement, while complete lipopolysaccharide is critical for bacterial survival in the host. A number of other virulence factors have been identified by both directed and random mutagenesis, including Pasteurella multocida toxin (PMT), putative surface adhesins and iron acquisition proteins. However, it is likely that many key virulence factors are yet to be identified, including those required for initial attachment and invasion of host cells and for persistence in a relatively nutrient poor and hostile environment. [source] FLSAC: A new scheme to defend against greedy behavior in wireless mesh networksINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 10 2009Soufiene Djahel Abstract The most commonly used medium access mechanism in wireless mesh networks is based on the CSMA/CA protocol. This protocol schedules properly the access to the medium among all the competing nodes. However, in a hostile environment, such as wireless mesh networks (WMNs), selfish or greedy behaving nodes may prefer to decline the proper use of the protocol rules in order to increase their bandwidth shares at the expense of the well-behaving nodes. In this paper, we focus on such misbehavior and in particular on the adaptive greedy misbehavior of a node in the context of WMN environment. In such environment, wireless nodes compete to gain access to the medium and communicate with a mesh router (MR). In this case, a greedy node may violate the protocol rules in order to earn extra bandwidth share upon its neighbors. In order to avoid its detection, this node may adopt different techniques and switch dynamically between each of them. To counter such misbehavior, we propose to use a fuzzy logic-based detection scheme. This scheme, dubbed FLSAC, is implemented in the MR/gateway to monitor the behavior of the attached wireless nodes and report any deviation from the proper use of the protocol. The simulation results of the proposed FLSAC scheme show robustness and its ability to detect and identify quickly any adaptive cheater. Copyright © 2009 John Wiley & Sons, Ltd. [source] A study of a routing attack in OLSR-based mobile ad hoc networksINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 11 2007Bounpadith Kannhavong Abstract A mobile ad hoc network (MANET) is a collection of mobile nodes which are able to communicate with each other without relying on predefined infrastructures or central administration. Due to their flexibilities and easy deployment, MANET can be applied in situation where network infrastructures are not available. However, due to their unique characteristics such as open medium and the lack of central administration, they are much more vulnerable to malicious attacks than a conventional infrastructured wireless network. MANET employs routing to provide connectivity for mobile nodes that are not within direct wireless transmission range. Existing routing protocols in MANET assume a trusted and cooperative environment. However, in hostile environment, mobile nodes are susceptible to various kinds of routing attacks. In this paper, we show that an OLSR MANET node is prone to be isolated by malicious attack called Node Isolation attack. After analysing the attack in detail, we present a technique to mitigate the impact of the attack and improve the performance of the network when the attack is launched. The results of our implementations illustrate that the proposed solution can mitigate the attack efficiently. Copyright © 2007 John Wiley & Sons, Ltd. [source] A study of the growth of Lactobacillus acidophilus in bovine, ovine and caprine milkINTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY, Issue 1 2003Alexandra P Drakoularakou The fermentation of reconstituted bovine, ovine and caprine milks with Lactobacillus acidophilus was investigated. Better growth of Lb. acidophilus was observed in ovine milk, but higher acidities developed in caprine milk. The high acidity produced after 12 h of fermentation (pH 3.9) created a hostile environment for the survival of the microorganism in caprine milk. [source] Maintenance of healthy skin: cleansing, moisturization, and ultraviolet protectionJOURNAL OF COSMETIC DERMATOLOGY, Issue 2007J Frank Nash PhD Summary Background, The human skin is exposed to an extraordinary hostile environment over the course of a lifetime. Whereas there are multiple product types that consumers may select to help preserve and protect the skin, at a minimum cleansing, moisturization, and protection against solar ultraviolet radiation are elements of any strategy designed for skin health. To achieve the greatest benefit from these treatment modalities, products must be carefully formulated, chosen, and used, since poorly designed or misused products may exacerbate symptoms associated with unhealthy skin. Aims, The objective of this review is to present the principle elements of cleansing, moisturization, and sun protection modalities that are, in some measure, responsible for maintaining healthy skin. Conclusion, Healthy skin is a universal desire of humans. The regular and proper use of cleansing, moisturization, and solar protection regimens plays a key role in maintaining skin health. These are lifetime practices wherein product technologies evolve even as the essential function remains. [source] A Military Challenge to Managing Feminine and Personal HygieneJOURNAL OF THE AMERICAN ACADEMY OF NURSE PRACTITIONERS, Issue 4 2001Diane Wind Wardell PhD PURPOSE To examine the personal remembrances of a group of military women concerning their experiences with hygiene issues during service in a hostile environment. DATA SOURCES Verbatim transcripts of focused interviews from 33 women who had been deployed to combat or the field were subjected to content analysis. Questions related to the womens' experiences in cleansing the body, collecting menses waste, and protecting against genitourinary infection in a hostile environment. CONCLUSIONS Management of personal hygiene needs was often difficult and consumed a great deal of time. Hygiene issues affected women's attitudes, practice, work, morale and coping. IMPLICATIONS FOR PRACTICE By understanding the hygiene needs and practices of military woman changes can be made that have the potential to affect health promotion and disease prevention strategies for all women. [source] Photonic circuits writing with UV pulsed laserPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 1 2007K. R. Kribich Abstract Photonics technology is employed in a growing number of applications. Biological and chemical sensors (E. Udd, Fiber Optic Sensors: An Introduction for Engineers and Scientists, Wiley, New York, 1991 [1]) for health and environment demand an adaptable technology. Network development towards the end-user requires more interconnecting components. Vision, lighting, data processing in hostile environment (spatial, military) need specific technologies. A flexible and low-cost process using good quality material is necessary. The sol-gel process is a chemical method to fabricate glasses at ambient pressure and moderate temperature. Hybrid materials (H.K. Schmidt et al., Proc. SPIE 3136, 220 (1997) [2]), mixing organic and inorganic parts, offer the advantages of polymer-like materials and glasses. We report on a new hybrid sol-gel technology to overcome the drawbacks of the formerly presented one (H. Krug, F. Teillantes, P.W. Oliviers, and H. Schmidt, Proc. SPIE 1758, 448 (1992) [3]). We present the material synthesis, an accurate and flexible fabrication process based on a pulsed UV laser lithography system and the characterisation of the optical waveguides and photonic circuits realised. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Media attention and the market for ,green' consumer productsBUSINESS STRATEGY AND THE ENVIRONMENT, Issue 3 2006John Thøgersen Abstract There are signs that a general ,counter-attack' is now being orchestrated against the ,greens'. This paper surveys the evidence regarding an ,issue-attention' cycle in environmental concern in Western Europe and North America. It furthermore discusses the role of the news media in creating the cycle. It is well documented that the mass media plays an important role in determining which issues receive high or low attention by the general public. However, not only does the media's assessment of what is newsworthy mean that ,green' businesses will eventually lose the current of a rising issue attention cycle, but also its mere success means that stories framing ,green' businesses in a negative light become newsworthy while positive stories lose their newsworthiness. Therefore, and despite a large and loyal customer base, many ,green' companies now find themselves in a much more hostile environment than a decade ago. Copyright © 2006 John Wiley & Sons, Ltd and ERP Environment. [source] Capability building through adversarial relationships: a replication and extension of Clarke and Roome (1999)BUSINESS STRATEGY AND THE ENVIRONMENT, Issue 5 2003Pursey P. M. A. R. Heugens Cooperative interorganizational relationships are seen by many as indispensable vehicles for accessing external knowledge and accumulating capabilities. Surprisingly, the question of whether companies can also build capabilities through adversarial relationships has received little attention. This paper reports a study of the learning,action network of a major Anglo-Dutch food and personal care company. The firm's present relationships with consumer representatives and environmental activists are strongly adversarial, due to the recent introduction of genetically modified ingredients. The study shows that companies can still build capabilities in a hostile environment, but that adversity influences capability building processes as well as capability content. Copyright © 2003 John Wiley & Sons, Ltd and ERP Environment. [source] Limits of life in hostile environments: no barriers to biosphere function?ENVIRONMENTAL MICROBIOLOGY, Issue 12 2009Jim P. Williams Summary Environments that are hostile to life are characterized by reduced microbial activity which results in poor soil- and plant-health, low biomass and biodiversity, and feeble ecosystem development. Whereas the functional biosphere may primarily be constrained by water activity (aw) the mechanism(s) by which this occurs have not been fully elucidated. Remarkably we found that, for diverse species of xerophilic fungi at aw values of , 0.72, water activity per se did not limit cellular function. We provide evidence that chaotropic activity determined their biotic window, and obtained mycelial growth at water activities as low as 0.647 (below that recorded for any microbial species) by addition of compounds that reduced the net chaotropicity. Unexpectedly we found that some fungi grew optimally under chaotropic conditions, providing evidence for a previously uncharacterized class of extremophilic microbes. Further studies to elucidate the way in which solute activities interact to determine the limits of life may lead to enhanced biotechnological processes, and increased productivity of agricultural and natural ecosystems in arid and semiarid regions. [source] Genome dynamics in major bacterial pathogensFEMS MICROBIOLOGY REVIEWS, Issue 3 2009Ole Herman Ambur Abstract Pathogenic bacteria continuously encounter multiple forms of stress in their hostile environments, which leads to DNA damage. With the new insight into biology offered by genome sequences, the elucidation of the gene content encoding proteins provides clues toward understanding the microbial lifestyle related to habitat and niche. Campylobacter jejuni, Haemophilus influenzae, Helicobacter pylori, Mycobacterium tuberculosis, the pathogenic Neisseria, Streptococcus pneumoniae, Streptococcus pyogenes and Staphylococcus aureus are major human pathogens causing detrimental morbidity and mortality at a global scale. An algorithm for the clustering of orthologs was established in order to identify whether orthologs of selected genes were present or absent in the genomes of the pathogenic bacteria under study. Based on the known genes for the various functions and their orthologs in selected pathogenic bacteria, an overview of the presence of the different types of genes was created. In this context, we focus on selected processes enabling genome dynamics in these particular pathogens, namely DNA repair, recombination and horizontal gene transfer. An understanding of the precise molecular functions of the enzymes participating in DNA metabolism and their importance in the maintenance of bacterial genome integrity has also, in recent years, indicated a future role for these enzymes as targets for therapeutic intervention. [source] Biogeochemistry of microbial mats under Precambrian environmental conditions: a modelling studyGEOBIOLOGY, Issue 2 2005E. K. HERMAN ABSTRACT Microbial mats have arguably been the most important ecosystem on Earth over its 3.5 Gyr inhabitation. Mats have persisted as consortia for billions of years and occupy some of Earth's most hostile environments. With rare exceptions (e.g. microbial mats developed on geothermal springs at Yellowstone National Park, USA), today's mats do not exist under conditions analogous to Precambrian habitats with substantially lower oxygen and sulphate concentrations. This study uses a numerical model of a microbial mat to investigate how mat composition in the past might have differed from modern mats. We present a numerical model of mat biogeochemistry that simulates the growth of cyanobacteria (CYA), colourless sulphur bacteria (CSB), and purple sulphur bacteria (PSB), with sulphate-reducing bacteria (SRB) and heterotrophic bacteria represented by parameterized sulphate reduction rates and heterotrophic consumption rates, respectively. Variations in the availability of light, oxygen, sulphide, and sulphate at the upper boundary of the mat are the driving forces in the model. Mats with remarkably similar biomass and chemical profiles develop in models under oxygen boundary conditions ranging from 2.5 × 10,13 to 0.25 mm and sulphate boundary concentrations ranging from 0.29 to 29 mm, designed to simulate various environments from Archean to modern. The modelled mats show little sensitivity to oxygen boundary conditions because, independent of the overlying oxygen concentrations, cyanobacterial photosynthesis creates similar O2 concentrations of 0.45,0.65 mm in the upper reaches of the mat during the photoperiod. Varying sulphate boundary conditions have more effect on the biological composition of the mat. Sulphide generated from sulphate reduction controls the magnitude and distribution of the PSB population, and plays a part in the distribution of CSB. CSB are the most sensitive species to environmental change, varying with oxygen and sulphide. [source] The Ties That Bind: Infanticide, Gender, and SocietyHISTORY COMPASS (ELECTRONIC), Issue 7 2010Brigitte H. Bechtold Infanticide is seen to be a horrific act, and yet this article finds that a growing body of literature on the topic is proving that infanticide is tied to human history. It provides a synthesis of the literature and identifies new directions in the scholarship since William L. Langer. These new directions move beyond the infanticidal act itself to an understanding of the circumstances that prompt it. They make clear that women's bodies tie them to their sexuality and the need to nurture children. Moreover, women must carry out these responsibilities while tied to hostile environments, cultural proscriptions, patriarchal law, and the violence of war. Infanticide scholarship, then, uncovers the numerous ties that bind women together as victims who are driven to infanticide and also as women who have exhibited agency in an attempt to move beyond victimhood and assert control over their own destiny. [source] Analyzing unidentified locked-joint failures in kinematically redundant manipulatorsJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 1 2005Manish Goel Robots are frequently used for operations in hostile environments. The very nature of these environments, however, increases the likelihood of robot failures. Common failure-tolerance techniques rely on effective failure detection and identification. Since a failure may not always be successfully identified, or, even if identified, may not be identified soon enough, it becomes important to consider the behavior of manipulators with unidentified failures. This work investigates the behavior of robots experiencing unidentified locked-joint failures in a general class of tasks characterized by point-to-point motion. Based on the analysis, a procedure for workspace evaluation is developed that allows for the identification of regions in the manipulator's workspace in which tasks may be completed even with such failures. © 2005 Wiley Periodicals, Inc. [source] | |||||||||||||||||||