1,887 research outputs found

    Bacteriophages as antimicrobial agents against bacterial contaminants in yeast fermentation processes

    Get PDF

    Innovations in cryoconservation of animal genetic resources: SECTION 4 The economics of gene banking:Animal Production and Health Guideline

    Get PDF
    The livestock sector faces a range of challenges, including climate change, emerging diseases, competition for natural resources and evolving demand for animal-source foods, which is increasing globally, especially in developing countries. Genetic diversity of livestock is a key resource for allowing livestock keepers to address these challenges, but this diversity has been in a state of decline. The diminishing genetic diversity thus represents yet another obstacle for sustainable livestock production. Cryoconservation (i.e. ex situ – in vitro conservation) of genetic resources through gene banking provides one of the most powerful tools governments and other stakeholders have to manage genetic diversity in both the short and long term and thereby provide future generations with the tools to meet the challenges ahead.Gene banking genetic resources fits within the context of the Global Plan of Action forAnimal Genetic Resources, which was developed and adopted by FAO Member Nations.Specifically, Strategic Priority 9 of the Global Plan of Action is “Establish or strengthen ex situ conservation programmes” and Strategic Priority 11 urges countries to “Develop approaches and technical standards for conservation. To assist countries in the implementation the Global Plan of Action, FAO worked with experts from around the world to prepare technical guidelines. In 2012 FAO published FAO Guidelines on Cryoconservation of animal genetic resources.Gene banking is a long-term effort that needs to be viewed in terms of decades rather than years, as demonstrated by similar systems for agricultural crops. The responsibility for establishing such resources lies squarely within governments’ roles of providing public goods and food security. Gene banking of animal genetic resources is a technology-intense undertaking and the associated technologies are in a continual state of research and development. The livestock sector also continues to evolve rapidly. Since the development and release of the previous guidelines, numerous changes have taken place. Critical among these is a greater appreciation of the opportunities for actively utilizing cryopreserved material to enhance management of in vivo populations, rather than as simply an “insurance policy” to protect breeds against extinction.This key development has led to further changes in gene bank management. First, interaction with users of the stored material has increased. This in turn has created a need to involve stakeholders more closely in the management of genetic collections and to better monitor and document the processes of gene banking to ensure quality management.Measures have been developed to help ensure high health and sanitary standards. New models and methods have been proposed for utilization of collections in the management of genetic diversity in vivo. Greater potential demand for stored material has also increased the need for expanded procedures and legal instruments, in some instances, to ensur

    New Bounds and Computations on Prime-Indexed Primes

    Get PDF
    In a 2009 article, Barnett and Broughan considered the set of prime-index primes. If the prime numbers are listed in increasing order (2, 3, 5, 7, 11, 13, 17, . . .), then the prime-index primes are those which occur in a prime-numbered position in the list (3, 5, 11, 17, . . .). Barnett and Broughan established a prime-indexed prime number theorem analogous to the standard prime number theorem and gave an asymptotic for the size of the n-th prime-indexed prime. We give explicit upper and lower bounds for π2(x), the number of prime-indexed primes up to x, as well as upper and lower bounds on the n-th prime-indexed prime, all improvements on the bounds from 2009. We also prove analogous results for higher iterates of the sequence of primes. We present empirical results on large gaps between prime-index primes, the sum of inverses of the prime-index primes, and an analog of Goldbach’s conjecture for prime-index primes

    Audiovisual integration increases the intentional step synchronization of side-by-side walkers

    Get PDF
    When people walk side-by-side, they often synchronize their steps. To achieve this, individuals might cross-modally match audiovisual signals from the movements of the partner and kinesthetic, cutaneous, visual and auditory signals from their own movements. Because signals from different sensory systems are processed with noise and asynchronously, the challenge of the CNS is to derive the best estimate based on this conflicting information. This is currently thought to be done by a mechanism operating as a Maximum Likelihood Estimator (MLE). The present work investigated whether audiovisual signals from the partner are integrated according to MLE in order to synchronize steps during walking. Three experiments were conducted in which the sensory cues from a walking partner were virtually simulated. In Experiment 1 seven participants were instructed to synchronize with human-sized Point Light Walkers and/or footstep sounds. Results revealed highest synchronization performance with auditory and audiovisual cues. This was quantified by the time to achieve synchronization and by synchronization variability. However, this auditory dominance effect might have been due to artifacts of the setup. Therefore, in Experiment 2 human-sized virtual mannequins were implemented. Also, audiovisual stimuli were rendered in real-time and thus were synchronous and co-localized. All four participants synchronized best with audiovisual cues. For three of the four participants results point toward their optimal integration consistent with the MLE model. Experiment 3 yielded performance decrements for all three participants when the cues were incongruent. Overall, these findings suggest that individuals might optimally integrate audiovisual cues to synchronize steps during side-by-side walking.info:eu-repo/semantics/publishedVersio

    Sensorimotor synchronization when walking side by side with a point light walker

    Get PDF
    [Excerpt] Synchronization of periodic movements like side-by-side walking [7] is frequently modeled by coupled oscillators [5] and the coupling strength is defined quantitatively [3]. In contrast, in most studies on sensorimotor synchronization (SMS), simple movements like finger taps are synchronized with simple stimuli like metronomes [4]. While the latter paradigm simplifies matters and allows for the assessment of the relative weights of sensory modalities through systematic variation of the stimuli [1], it might lack ecological validity. Conversely, using more complex movements and stimuli might complicate the specification of mechanisms underlying coupling. We merged the positive aspects of both approaches to study the contribution of auditory and visual information on synchronization during side-by-side walking. As stimuli, we used Point Light Walkers (PLWs) and auralized steps sound; both were constructed from previously captured walking individuals [2][6]. PLWs were retro-projected on a screen and matched according to gender, hip height, and velocity. The participant walked for 7.20m side by side with 1) a PLW, 2) steps sound, or 3) both displayed in temporal congruence. Instruction to participants was to synchronize with the available stimuli. [...]Acknowledgments: [Supported by Fundação Bial (Grant 77/12) and Fundação para a Ciência e Tecnologia - FCT: SFRH/BD/88396/2012; EXPL/MHC-PCN/0162/2013; FCOMP-01-0124 - FEDER-022674 and PEst-C/CTM/U10264/2011; FCOMP-01-0124-FEDER-037281 and PEstC/EEI/LA0014/2013. This work was financed by FEDER grants through the Operational Competitiveness Program – COMPETE]

    Остаточный энергетический потенциал низкокалорийных отходов угольного производства: критерии оценки

    Get PDF
    Розглянуто загальні проблеми, пов’язані із залученням до господарського обороту низькокалорійних відходів видобування і збагачення вугілля. Наведено результати систематизації і узагальнення інформації про їх технічні характеристики, викладено методичні підходи до вибору критеріїв оцінки їх енергетичного потенціалу. Ключові слова: вугілля, енергозбереження, відходи виробництва, вторинні ресурси.Рассмотрены общие проблемы, связанные с вовлечением в хозяйственный оборот низкокалорийных отходов добычи и обогащения угля. Приведены результаты систематизации и обобщения информации об их технических характеристиках, изложены методические подходы к выбору критериев оценки их энергетического потенциала. Ключевые слова: уголь, энергосбережение, отходы производства, вторичные ресурсы.The general problems connected with involving of low-calorie wastes of mining process and coal enrichment into economic turnover are considered. The results of systematization and generalization of the information about their technical characteristics are shown; methodical approaches to choosing the criteria of estimation of their energy potential are presented. Keywords: coal, energy saving, production wastes, secondary resources

    The Campylobacter jejuni MarR-like transcriptional regulators RrpA and RrpB both influence bacterial responses to oxidative and aerobic stresses.

    Get PDF
    The ability of the human intestinal pathogen Campylobacter jejuni to respond to oxidative stress is central to bacterial survival both in vivo during infection and in the environment. Re-annotation of the C. jejuni NCTC11168 genome revealed the presence of two MarR-type transcriptional regulators Cj1546 and Cj1556, originally annotated as hypothetical proteins, which we have designated RrpA and RrpB (regulator of response to peroxide) respectively. Previously we demonstrated a role for RrpB in both oxidative and aerobic (O2) stress and that RrpB was a DNA binding protein with auto-regulatory activity, typical of MarR-type transcriptional regulators. In this study, we show that RrpA is also a DNA binding protein and that a rrpA mutant in strain 11168H exhibits increased sensitivity to hydrogen peroxide oxidative stress. Mutation of either rrpA or rrpB reduces catalase (KatA) expression. However, a rrpAB double mutant exhibits higher levels of resistance to hydrogen peroxide oxidative stress, with levels of KatA expression similar to the wild-type strain. Mutation of either rrpA or rrpB also results in a reduction in the level of katA expression, but this reduction was not observed in the rrpAB double mutant. Neither the rrpA nor rrpB mutant exhibits any significant difference in sensitivity to either cumene hydroperoxide or menadione oxidative stresses, but both mutants exhibit a reduced ability to survive aerobic (O2) stress, enhanced biofilm formation and reduced virulence in the Galleria mellonella infection model. The rrpAB double mutant exhibits wild-type levels of biofilm formation and wild-type levels of virulence in the G mellonella infection model. Together these data indicate a role for both RrpA and RrpB in the C. jejuni peroxide oxidative and aerobic (O2) stress responses, enhancing bacterial survival in vivo and in the environment

    Conserving the Mesoamerican herpetofauna: The most critical case of the priority level one endemic species

    Get PDF
    Of significant biodiversity importance, the Mesoamerican herpetofauna now increases at a rate of approximately 35 species annually. As its size increases, however, the global problem of biodiversity decline continues to worsen with time. Recently, a set of conservation priority levels was established for individual species based on a combination of physiographic distribution and Environmental Vulnerability Score (EVS). The 18 such levels identified range from level one, encompassing species that occupy a single physiographic region and with a high EVS, to level 18, including species that inhabit six physiographic regions and have a low EVS. For the Mesoamerican herpetofauna, the greatest number of species is placed in level one, amounting to 970 taxa with documentable distributions. From one to 149 priority level one species are found in 20 of the 21 physiographic regions recognized in Mesoamerica. Slightly more than three-quarters of the priority level one species of anurans, salamanders, and squamates are found in the Baja California Peninsula and six montane regions in Mexico and Central America. Conservation biology, thus far, has not been successful at reversing the steady loss of biodiversity nor at placing biodiversity decline on the global agenda. In addition, humans are becoming increasingly divorced from contact with the natural world and, thus, less aware of the life-threatening impact they are having on the planet’s life-support systems. Given this situation, the authors of this paper have become increasingly devoted to trying to understand why humans in general exhibit the highly dangerous anthropocentric worldview. As have other biologists, the authors ascribe this behavior to what is known as “the mismanagement of the human mind.” This mismanagement of the human mind is believed to result from a cascade of psychological ailments giving rise to increasingly restrictive forms of centristic thinking. In the final analysis, these types of thinking appear likely to doom to failure any efforts to establish for perpetuity protected areas that can harbor the priority level one species identified in this and earlier papers. Until and unless the anthropocentric worldview can be transformed into a worldview consonant with the realities of how life operates on planet Earth, we humans are not only endangering ourselves but also all other life. This article discusses the implications of this worldview for the potential conservation of the priority level one endemic species of the Mesoamerica herpetofauna

    Etude de couches limites oscillantes par vélocimétrie laser Doppler

    No full text
    International audienceLe transport sédimentaire induit par les vagues à l'approche de la côte est piloté par des processus non linéaires et turbulents. Les non-linéarités des vagues se caractérisent par une dissymétrie de vitesse (les crêtes hautes des vagues sont de courte durée et les creux peu profonds de longue durée) et une asymétrie de vitesse (ou dissymétrie d'accélération, caractérisant la raideur des fronts). Des études récentes indiquent que des fronts raides (vagues asymétriques) produisent des vitesses dissymétriques dans la couche limite. Ainsi, pour développer des formules de prédiction de transport des sédiments, la compréhension détaillée de la dynamique de la couche limite de fond et des contraintes de cisaillement sous les ondes de surface apparaît essentielle. Ceci justifie de chercher à réaliser des mesures de vitesse dans les tous premiers millimètres au-dessus du lit.Par ailleurs, la caractérisation de la turbulence sous les vagues déferlantes reste une question ouverte, en particulier pour chercher à évaluer la part provenant de la vague déferlée de celle produite par frottement au fond.Actuellement, l’essentiel de notre connaissance des couches limites oscillantes est issu de mesures réalisées sur des fonds fixes horizontaux. En laboratoire, l’évolution des non-linéarités des vagues, lors de leur propagation et de leur déferlement, a été principalement étudiée pour des plages de pentes relativement fortes (> 1:40). Cependant, des études de terrain récentes sur des plages réelles de pentes moins raides (1:80) ont montré que certains processus non-linéaires sont différents par rapport aux cas des plages de pentes relativement raides (> 1:40). Cette constatation a motivé le lancement d’une série d'expériences de laboratoire dans le cadre du projet européen GLOBEX sur une plage à fond fixe de pente 1:80
    corecore