568 research outputs found

    Reproductive performance of Norwegian cattle from 1985 to 2005: trends and seasonality

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    Declining reproductive performance is a serious breeding concern in many countries. To reveal the situation in Norwegian cattle, trends in reproductive performance were studied using insemination reports from 1985 to 2005 and data based on herd recording files from 1989 to 2005. The total number of first services was 469.765 in 1985 declining to 335.712 in 2005. The number of recorded herds and animals declined from 21.588 to 14.718 and 360.289 to 309.452 from 1989 to 2005, respectively. Sixty days non-return rate after single inseminations (NR60) increased from 68.1 in 1985 to 72.7% in 2005 (p < 0.001) and the number of services per inseminated animal (NIA) decreased from 1.8 to 1.6 (p < 0.001) from 1985 to 2005. However, return rates 0–3 days post insemination (RR0-3) increased from 6 to 12% in the same period (p < 0.001). NR60 was higher and the RR0-3 was lower in the summer season compared to the winter season during the whole period. A fertility index (FS), has been calculated from the herd recording files each year from 1989 to 2005. The average FS-index did not show a significant trend and the calving interval was also fairly constant between 12.4 and 12.6 months during this period. The average interval from calving to first and last insemination, respectively, increased from a low of 79 and 102 days in 1990 to a high of 86 and 108 days in 2005. Both intervals were consistently longer for cows in first lactation than for cows in later lactations. The percentage of inseminated animals reported culled because of poor fertility decreased from 6.0% in 1989 to 4.6% in 1996 and thereafter again increased to 6% in 2005. In conclusion, most fertility measures, mainly comprising the Norwegian Red (NRF) breed, show a relatively high level of reproductive performance with a positive or a relatively constant trend during the last two decades

    A Worldwide Phylogeography for the Human X Chromosome

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    BACKGROUND: We reasoned that by identifying genetic markers on human X chromosome regions where recombination is rare or absent, we should be able to construct X chromosome genealogies analogous to those based on Y chromosome and mitochondrial DNA polymorphisms, with the advantage of providing information about both male and female components of the population. METHODOLOGY/PRINCIPAL FINDINGS: We identified a 47 Kb interval containing an Alu insertion polymorphism (DXS225) and four microsatellites in complete linkage disequilibrium in a low recombination rate region of the long arm of the human X chromosome. This haplotype block was studied in 667 males from the HGDP-CEPH Human Genome Diversity Panel. The haplotypic diversity was highest in Africa (0.992+/-0.0025) and lowest in the Americas (0.839+/-0.0378), where no insertion alleles of DXS225 were observed. Africa shared few haplotypes with other geographical areas, while those exhibited significant sharing among themselves. Median joining networks revealed that the African haplotypes were numerous, occupied the periphery of the graph and had low frequency, whereas those from the other continents were few, central and had high frequency. Altogether, our data support a single origin of modern man in Africa and migration to occupy the other continents by serial founder effects. Coalescent analysis permitted estimation of the time of the most recent common ancestor as 182,000 years (56,700-479,000) and the estimated time of the DXS225 Alu insertion of 94,400 years (24,300-310,000). These dates are fully compatible with the current widely accepted scenario of the origin of modern mankind in Africa within the last 195,000 years and migration out-of-Africa circa 55,000-65,000 years ago. CONCLUSIONS/SIGNIFICANCE: A haplotypic block combining an Alu insertion polymorphism and four microsatellite markers on the human X chromosome is a useful marker to evaluate genetic diversity of human populations and provides a highly informative tool for evolutionary studies

    Exploring the transdisciplinary trajectory of suggestibility

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    Traditionally considered a deficiency in will power and rationality, suggestibility has proven a troublesome concept for psychology. It was forgotten, rediscovered, denounced, undermined experimentation and recently became the ambiguous issue at the centre of concern about child witness' credibility in sexual abuse cases. This paper traces the history of suggestibility to show how it raises the 'paradox of the psychosocial'. Drawing on the work of Deleuze and Stengers, and on interviews with legal practitioners, this paper demonstrates how suggestibility carries this paradox into theory, research and legal practice. It thereby opens up a transdisciplinary perspective, allowing for questions of power and knowledge to be asked as performative questions. In the spirit of a process-centred ontology for psychology, I argue that suggestibility constitutes a 'rhythm of problematization', a folding, giving a subversive insight into dynamics of subjectification and application, and offering new perspectives towards issues of children's credibility and protection

    Towards real-time cardiovascular magnetic resonance guided transarterial CoreValve implantation: in vivo evaluation in swine

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    <p>Abstract</p> <p>Background</p> <p>Real-time cardiovascular magnetic resonance (rtCMR) is considered attractive for guiding TAVI. Owing to an unlimited scan plane orientation and an unsurpassed soft-tissue contrast with simultaneous device visualization, rtCMR is presumed to allow safe device navigation and to offer optimal orientation for precise axial positioning. We sought to evaluate the preclinical feasibility of rtCMR-guided transarterial aortic valve implatation (TAVI) using the nitinol-based Medtronic CoreValve bioprosthesis.</p> <p>Methods</p> <p>rtCMR-guided transfemoral (n = 2) and transsubclavian (n = 6) TAVI was performed in 8 swine using the original CoreValve prosthesis and a modified, CMR-compatible delivery catheter without ferromagnetic components.</p> <p>Results</p> <p>rtCMR using TrueFISP sequences provided reliable imaging guidance during TAVI, which was successful in 6 swine. One transfemoral attempt failed due to unsuccessful aortic arch passage and one pericardial tamponade with subsequent death occurred as a result of ventricular perforation by the device tip due to an operating error, this complication being detected without delay by rtCMR. rtCMR allowed for a detailed, simultaneous visualization of the delivery system with the mounted stent-valve and the surrounding anatomy, resulting in improved visualization during navigation through the vasculature, passage of the aortic valve, and during placement and deployment of the stent-valve. Post-interventional success could be confirmed using ECG-triggered time-resolved cine-TrueFISP and flow-sensitive phase-contrast sequences. Intended valve position was confirmed by ex-vivo histology.</p> <p>Conclusions</p> <p>Our study shows that rtCMR-guided TAVI using the commercial CoreValve prosthesis in conjunction with a modified delivery system is feasible in swine, allowing improved procedural guidance including immediate detection of complications and direct functional assessment with reduction of radiation and omission of contrast media.</p

    Depression and anxiety, an Indicated Prevention (DIP) protocol in homes for the elderly: feasibility and (cost) effectiveness of a stepped care programme

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    BACKGROUND: Depressive and anxiety disorders are a very common, serious and underdetected problem in homes for the elderly. Elderly persons in residential homes are at high risk for developing major depressive and anxiety disorders, and, therefore, deserve attention with regard to prevention. METHODS/DESIGN: This protocol describes a randomised trial on the feasibility and (cost) effectiveness of a stepped-care programme for prevention of depressive and anxiety disorders in homes for the elderly. The main outcome measure is the incidence of depressive and anxiety disorder in one year with a two years follow up. Secondary outcomes are symptoms of depression and anxiety, quality of life, direct health care costs and satisfaction with treatment. DISCUSSION: The number of studies examining the effects of preventive interventions on the incidence of mental disorders in the elderly population is very small. However, indicated prevention by means of a stepped-care programme seems to be an important option for decreasing the burden of illness for residents and their caregivers. This study contributes to the body of knowledge in this field. Positive effects may contribute to further use and development of tailored, (cost-) effective and easy to use interventions in a preventive stepped-care programme. TRIAL REGISTRATION: The Dutch Cochrane Centre, ISRCTN2754073

    International entrepreneurship in SMEs: a study of influencing factors in the textile industry

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    The final publication is available at Springer via http://dx.doi.org/10.1007/s11365-012-0242-3International entrepreneurship is an incipient research area with a rapidly increasing body of knowledge and contributions. An important part of this literature has focused on the analysis of the contributing factors to IE development. From these studies, this work attempts to analyse and validate through an integrative model the effect on this construct in SME of some of the main factors proposed by the literature such as Skills and Competences, Attitude and Proactiveness, Creativity and Innovation, Networking, Employees and Activity. To proceed with this aim, we conducted an empirical research focused on 174 textile SME in Spain. The results obtained confirm a positive relationship between the studied factors and the IE development. In consequence, this work agrees with previous literature that point out the need to use multi-theoretical perspectives, combining multiple factors.Gil Pechuán, I.; Expósito Langa, M.; Tomas Miquel, JV. (2013). International entrepreneurship in SMEs: a study of influencing factors in the textile industry. International Entrepreneurship and Management Journal. 9(1):45-57. doi:10.1007/s11365-012-0242-3S455791Akgün, A., Keskin, H., & Byrne, J. (2012). Organizational emotional memory. Management Decision, 50(1), 95–114.Andersén, J. (2011). Strategic resources and firm performance. Management Decision, 49(1), 87–98.Anderson, A. R., Dodd, S. D., & Jack, S. L. (2012). Entrepreneurship as connecting: some implications for theorising and practice. Management Decision, 50(5), 958–971.Appelbaum, S. H., Roy, M., & Gilliland, T. (2011). Globalization of performance appraisals: theory and applications. Management Decision, 49(4), 570–585.Arribas, I., Hernández, P., Urbano, A., & Vila, J. E. (2012). Are social and entrepreneurial attitudes compatible? A behavioral and self-perceptional analysis. Management Decision, 50(10), 1739–1757.Audretsch, D. (2012). Entrepreneurship research. Management Decision, 50(5), 755–764.Autio, E., Sapienza, H. J., & Almeida, J. G. (2000). Effects of age at entry, knowledge intensity, and imitability on international growth. Academy of Management Journal, 43, 909–924.Bannon, L. (1998). Mattel plans to double sales abroad. Wall Street Journal, February 11, (A3 and A8).Battistella, C., Biotto, G., & De Toni, A. (2012). From design driven innovation to meaning strategy. Management Decision, 50(4), 718–743.Bell, J., McNaughton, J., Young, R., & Crick, D. (2003). Towards an integrative model of small firm internationalization. Journal of International Entrepreneurship, 1, 339–362.Bonzo, P., Valadares de Oliveira, P., & McCormarck. (2012). Planning, capabilities, and performance: an integrated value approach. Management Decision, 50(6), 1001–1021.Bossak, J., & Nagashima, S. (1997). Corporate strategies for a borderless world: sharpening your competitive edge. Tokyo: Asian Productivity Organization.Cambra-Fierro, J., Florin, J., Perez, L., & Whitelock, J. (2011). Inter-firm market orientation as antecedent of knowledge transfer, innovation and value creation in networks. Management Decision, 49(3), 444–467.Cantarello, S., Nosella, A., Petroni, G., & Venturini, K. (2011). External technology sourcing: evidence from design-driven innovation. Management Decision, 49(6), 962–983.Chang, Y. Y., Hughes, M., & Hotho, S. (2011). Internal and external antecedents of SMEs’ innovation ambidexterity outcomes. Management Decision, 49(10), 1658–1676.Chaston, I., & Scott, G. J. (2012). Entrepreneurship and open innovation in an emerging economy. Management Decision, 50(7), 1161–1177.Coviello, N. E., & Jones, M. V. (2004). Methodological issues in international entrepreneurship research. Journal of Business Venturing, 19, 485–508.Coviello, N. E., & McAuley, A. (1999). Internationalization and the smaller firm: a review of contemporary empirical research. Management International Review, 39, 223–256.Covin, J., & Slevin, D. (1989). Strategic management of small firms in hostile and benign environments. Strategic Management Journal, 10(1), 75–87.Covin, J., & Slevin, D. (1991). A conceptual model of entrepreneurship as firm behavior. Entrepreneurship Theory and Practice, 16, 7–25.Davis, D., Morris, M., & Allen, J. (1991). Perceived environmental turbulence and its effect on selected entrepreneurship, marketing, and organizational characteristics in industrial firms. Journal of the Academy of Marketing Science, 19(1), 43–51.Dean, C. C., Thibodeaux, M. S., Beyerlein, M., Ebrahimi, B., & Molina, D. (1993). Corporate entrepreneurship and competitive aggressiveness. A comparison of U.S. firms operating in eastern Europe and the Commonwealth of Independent States with U.S. firms in other high-risk environments. Advances in International Comparative Management, 8, 31–54.Dess, G. G., & Robinson, R. B. (1984). Measuring organizational performance in the absence of objective measures: the case of privately held firms and conglomerate business units. Strategic Management Journal, 5, 265–273.Dess, G. G., Lumpkin, G. T., & Covin, J. G. (1997). Entrepreneurial strategy making and firm performance: tests of contingency and configurational models. Strategic Management Journal, 18, 677–695.Díaz-Casero, J. C., Díaz-Aunión, A., Sánchez-Escobedo, M. C., Coduras-Martinez, A., & Hernández-Mogollón, R. (2012). Economic freedom and entrepreneurial activity. Management Decision, 50(9), 1686–1711.Dimitratos, P., & Plakoyiannaki, E. (2003). Theoretical foundations of an international entrepreneurial culture. Journal of International Entrepreneurship, 1, 187–215.Dubini, P., & Aldrich, H. (1991). Personal and extended networks are central to the entrepreneurial process. Journal of Business Venturing, 6, 305–313.Felício, J. A., Rodrigues, R., & Caldeirinha, V. R. (2012). The effect of intrapreneurship on corporate performance. Management Decision, 50(10), 1717–1738.Goktan, A. B., & Miles, G. (2011). Innovation speed and radicalness: are they inversely related? Management Decision, 49(4), 533–547.Gómez-Haro, S., Aragón-Correa, J. A., & Cordón-Pozo, E. (2011). Differentiating the effects of the institutional environment on corporate entrepreneurship. Management Decision, 49(10), 1677–1693.Hitt, M. A., Ireland, R. D., Camp, S. M., & Sexton, L. D. (2001). Strategic entrepreneurship: entrepreneurial strategies for wealth creation [Special Issue]. Strategic Management Journal, 22(6), 479–492.Hotho, S., & Champion, K. (2011). Small businesses in the new creative industries: innovation as a people management challenge. Management Decision, 49(1), 29–54.Hu, Y.-S. (1995). The international transferability of competitive advantage. California Management Review, 37(4), 73–88.Huarng, K. H., & Yu, T. H. K. (2011). Entrepreneurship, process innovation and value creation by a non-profit SME. Management Decision, 49(2), 284–296.Jones, M. V. (1999). The internationalization of small UK high technology based firms. Journal of International Marketing, 7, 15–41.Jones, M. V., & Coviello, N. E. (2005). Internationalization: conceptualising and entrepreneurial process of behaviour in time. Journal of International Business Studies, 36(3):284–303.Khandwalla, P. (1977). The design of organizations. New York: Harcourt Brace Jovanovich.Knight, G. A., & Cavusgil, S. T. (2004). Innovation, organization capabilities, and the born-global firm. Journal of International Business Studies, 35, 124–141.Kropp, F., Lindsay, N. J., & Shoham, A. (2006). Entrepreneurial, market, and learning orientations and international entrepreneurial business venture performance in South African firms. International Marketing Review, 23(5), 504–523.Liebeskind, J. P. (1996). Knowledge, strategy, and the theory of the firm. Strategic Management Journal, 17, 93–107.Lumpkin, G. T., & Dess, G. G. (1996). Clarifying the entrepreneurial construct and linking it to performance. Academy of Management Review, 21, 135–172.McDougall, P. P., & Oviatt, B. M. (2000). International entrepreneurship: the intersection of two research paths. Academy of Management Journal, 43, 902–908.McDougall, P. P., Shane, S., & Oviatt, B. M. (1994). Explaining the formation of international new ventures: the limits of theories from international business research. Journal of Business Venturing, 9, 469–487.McGrath, R. G., MacMillan, I. C., & Venkataraman, S. (1995). Global dimensions of new competencies. In S. Birley & I. C. MacMillan (Eds.), International entrepreneurship. New York: Routledge.McNaughton, R. B. (2001). The export mode decision-making process in small knowledge- intensive firms. Market Intelligence and Planning, 19, 12–20.McNaughton, R. B. (2003). The number of export markets that a firm serves: process models versus the born-global phenomenon. Journal of International Entrepreneurship, 1, 297–311.Miles, R. E., & Snow, C. C. (1978). Organizational strategy, structure and process. New York: McGraw-Hill.Miller, D. (1983). The correlates of entrepreneurship in three types of firms. Management Science, 29(7), 770–791.Miller, D., & Friesen, P. (1984). Organizations: a quantum view. Englewood Cliffs: Prentice-Hall.Morrow, J. F. (1988). International entrepreneurship: a new growth opportunity. New Management, 3, 59–61.Murphy, G. B., Trailer, J. W., & Hill, R. C. (1996). Measuring performance in entrepreneurship research. Journal of Business Research, 36, 15–23.Naman, J. L., & Slevin, D. P. (1993). Entrepreneurship and the concept of fit: a model and empirical tests. Strategic Management Journal, 14, 137–153.Naranjo-Valencia, J. C., Jiménez-Jiménez, D., & Sanz-Valle, R. (2011). Innovation or imitation? The role of organizational culture. Management Decision, 49(1), 55–72.Oviatt, B. M., & McDougall, P. P. (1994). Toward a theory of international new ventures. Journal of International Business Studies, 25(1), 45–64.Oviatt, B. M., & McDougall, P. P. (1999). A framework for understanding accelerated international entrepreneurship. In R. Wright (Ed.), Research in global strategic management (pp. 23–40). Stamford: JAI Press.Oviatt, B. M., & McDougall, P. P. (2005). Defining international entrepreneurship and modeling the speed of internalization. Entrepreneurship Theory & Practice, 29(5), 537–554.Peiris, I.K., Akoorie, M.E.M., & Sinha, P.N. (2012). International entrepreneurship: A critical analysis of studies in the past two decades and future directions for research. Journal of International Entrepreneurship. Article in press.Pinchot, G., III. (1985). Intrapreneuring: why you don’t have to leave the corporation to become entrepreneur. New York: Harper and Row Publishers.Porter, M. (1990). The competitive advantage of nations. London: Collier-Macmillan.Renko, M., Shrader, R. C., & Simon, M. (2012). Perception of entrepreneurial opportunity: a general framework. Management Decision, 50(7), 1233–1251.Sandulli, F. D., Fernandez-Menendez, J., Rodriguez-Duarte, A., & Lopez-Sanchez, J. I. (2012). Testing the Schumpeterian hypotheses on an open innovation framework. Management Decision, 50(7), 1222–1232.Santos, F. J., Romero, I., & Fernández-Serrano, J. (2012). SMEs and entrepreneurial quality from a macroeconomic perspective. Management Decision, 50(8), 1382–1395.Shama, A. (1995). Entry strategies of U.S. firms to the former Soviet Bloc and Eastern Europe. California Management Review, 37(3), 90–109.Simon, H. (1996). Hidden champions: lessons from 500 of the world’s best unknown companies. Boston: Harvard Business School Press.Singh, S., Darwish, T. K., Costa, A. C., & Anderson, N. (2012). Measuring HRM and organisational performance: concepts, issues, and framework. Management Decision, 50(4), 651–667.Smart, T. (1996). GE’s Welch: ‘Fighting like hell to be No. 1’. Business Week, July 8, 48.Snow, C., & Hrebiniak, L. (1980). Strategy, distinctive competence, and organizational performance. Administrative Science Quarterly, 25, 317–336.Stevenson, H. H., & Jarillo, J. C. (1990). A paradigm of entrepreneurship: entrepreneurial management. Strategic Management Journal, 11, 17–27.Styles, C., & Seymour, R. G. (2006). Opportunities for marketing researchers in international entrepreneurship. International Marketing Review, 23(2), 126–145.Turner, R., Ledwith, A., & Kelly, J. (2012). Project management in small to medium-sized enterprises: tailoring the practices to the size of company. Management Decision, 50(5), 942–957.Venkatraman, N., & Ramanujam, V. (1986). Measurement of business performance in strategy research: a comparison of approaches. Academy of Management Review, 11, 801–814.Vlasic, B. (1998). The little car that could carry Chrysler overseas. Business Week, 19, 39.Welbourne, T. M., Neck, H., & Meyer, G. D. (2012). The entrepreneurial growth ceiling: using people and innovation to mitigate risk and break through the growth ceiling in initial public offerings. Management Decision, 50(5), 778–796.Williamson, P. J. (1997). Asia’s new competitive game. Harvard Business Review, 75(5), 55–67.Yeoh, P. L. (2004). International learning: antecedents and performance implications among newly internationalizing companies in an exporting context. International Marketing Review, 21(4/5), 511–535.Zahra, S. A. (1991). Predictors and financial outcomes of corporate entrepreneurship. An exploratory study. Journal of Business Venturing, 6(4), 259–285.Zahra, S. A. (1993a). Environment, corporate entrepreneurship and financial performance. A taxonomic approach. Journal of Business Venturing, 8(4), 319–340.Zahra, S. A. (1993b). A conceptual model of entrepreneurship as firm behavior: a critique and extensión. Entrepreneurship Theory and Practice, 17(4), 5–21.Zahra, S. A., & George, G. (2002). International entrepreneurship: the current status of the field and future agenda. In M. A. Hitt, R. D. Ireland, S. M. Camp, & D. L. Sexton (Eds.), Strategic entrepreneurship: creating a new mindset. Oxford: Blackwell Publishers.Zahra, S. A., Jennings, D. F., & Kuratko, D. F. (1999). The antecedents and consequences of firm-level entrepreneurship: the state of the field. Entrepreneurship Theory and Practice, 24(2), 45–63.Zhou, L. (2007). The effects of entrepreneurial proclivity and foreign market knowledge on early internationalization. Journal of World Business, 42(3), 281–293

    Molecular Networks in FGF Signaling: Flotillin-1 and Cbl-Associated Protein Compete for the Binding to Fibroblast Growth Factor Receptor Substrate 2

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    Fibroblast growth factor receptor substrate 2 (FRS2α) is a signaling adaptor protein that regulates downstream signaling of many receptor tyrosine kinases. During signal transduction, FRS2 can be both tyrosine and threonine phosphorylated and forms signaling complexes with other adaptor proteins and tyrosine phosphatases. We have here identified flotillin-1 and the cbl-associated protein/ponsin (CAP) as novel interaction partners of FRS2. Flotillin-1 binds to the phosphotyrosine binding domain (PTB) of FRS2 and competes for the binding with the fibroblast growth factor receptor. Flotillin-1 knockdown results in increased Tyr phosphorylation of FRS2, in line with the inhibition of ERK activity in the absence of flotillin-1. CAP directly interacts with FRS2 by means of its sorbin homology (SoHo) domain, which has previously been shown to interact with flotillin-1. In addition, the third SH3 domain in CAP binds to FRS2. Due to the overlapping binding domains, CAP and flotillin-1 appear to compete for the binding to FRS2. Thus, our results reveal a novel signaling network containing FRS2, CAP and flotillin-1, whose successive interactions are most likely required to regulate receptor tyrosine kinase signaling, especially the mitogen activated protein kinase pathway

    Simukunin from the Salivary Glands of the Black Fly Simulium vittatum Inhibits Enzymes That Regulate Clotting and Inflammatory Responses

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    BACKGROUND: Black flies (Diptera: Simuliidae) feed on blood, and are important vectors of Onchocerca volvulus, the etiolytic agent of River Blindness. Blood feeding depends on pharmacological properties of saliva, including anticoagulation, but the molecules responsible for this activity have not been well characterized. METHODOLOGY/PRINCIPAL FINDINGS: Two Kunitz family proteins, SV-66 and SV-170, were identified in the sialome of the black fly Simulium vittatum. As Kunitz proteins are inhibitors of serine proteases, we hypothesized that SV-66 and/or -170 were involved in the anticoagulant activity of black fly saliva. Our results indicated that recombinant (r) SV-66 but not rSV-170 inhibited plasma coagulation. Mutational analysis suggested that SV-66 is a canonical BPTI-like inhibitor. Functional assays indicated that rSV66 reduced the activity of ten serine proteases, including several involved in mammalian coagulation. rSV-66 most strongly inhibited the activity of Factor Xa, elastase, and cathepsin G, exhibited lesser inhibitory activity against Factor IXa, Factor XIa, and plasmin, and exhibited no activity against Factor XIIa and thrombin. Surface plasmon resonance studies indicated that rSV-66 bound with highest affinity to elastase (K(D) = 0.4 nM) and to the active site of FXa (K(D) = 3.07 nM). We propose the name "Simukunin" for this novel protein. CONCLUSIONS: We conclude that Simukunin preferentially inhibits Factor Xa. The inhibition of elastase and cathepsin G further suggests this protein may modulate inflammation, which could potentially affect pathogen transmission

    Does Environmental Enrichment Reduce Stress? An Integrated Measure of Corticosterone from Feathers Provides a Novel Perspective

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    Enrichment is widely used as tool for managing fearfulness, undesirable behaviors, and stress in captive animals, and for studying exploration and personality. Inconsistencies in previous studies of physiological and behavioral responses to enrichment led us to hypothesize that enrichment and its removal are stressful environmental changes to which the hormone corticosterone and fearfulness, activity, and exploration behaviors ought to be sensitive. We conducted two experiments with a captive population of wild-caught Clark's nutcrackers (Nucifraga columbiana) to assess responses to short- (10-d) and long-term (3-mo) enrichment, their removal, and the influence of novelty, within the same animal. Variation in an integrated measure of corticosterone from feathers, combined with video recordings of behaviors, suggests that how individuals perceive enrichment and its removal depends on the duration of exposure. Short- and long-term enrichment elicited different physiological responses, with the former acting as a stressor and birds exhibiting acclimation to the latter. Non-novel enrichment evoked the strongest corticosterone responses of all the treatments, suggesting that the second exposure to the same objects acted as a physiological cue, and that acclimation was overridden by negative past experience. Birds showed weak behavioral responses that were not related to corticosterone. By demonstrating that an integrated measure of glucocorticoid physiology varies significantly with changes to enrichment in the absence of agonistic interactions, our study sheds light on potential mechanisms driving physiological and behavioral responses to environmental change
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