114 research outputs found
Nectar palatability can selectively filter bird and insect visitors to coral tree flowers
Secondary compounds in nectar may play a decisive role in determining the
spectrum of floral visitors on plants. Flowers of the African coral tree Erythrina caffra are
visited mainly by generalist passerine nectarivores, such as weavers and bulbuls. As the
nectar of this species tastes very bitter to humans, it was hypothesized that secondary
compounds may repel sunbirds and honeybees which are common in the same habitats yet
seldom consume the nectar. We conducted choice tests using fresh nectar and both sucrose
and hexose (glucose/fructose) solutions of the same concentration as the nectar. Whitebellied
Sunbirds (Cinnyris talatala) were repelled by nectar of both E. caffra and a related
species Erythrina lysistemon, but Dark-capped Bulbuls (Pycnonotus tricolor) did not
discriminate between the Erythrina nectar and control sugar solution in terms of amounts
consumed. Honeybees (Apis mellifera scutellata) probed exposed droplets of E. caffra
nectar and a control sugar solution at the same rate, suggesting that there is no volatile
deterrent, but they immediately withdrew their proboscis far more often from the droplets
of Erythrina nectar than they did from the sugar solution, suggesting that they find Erythrina
nectar distasteful. These results contribute to a growing awareness that non-sugar
components of nectar can play important functional roles in plant pollination systems.South African National Research Foundation (NRF)http://link.springer.com/journal/106822016-03-31hb201
TRPM2 channel deficiency prevents delayed cytosolic Zn²⁺ accumulation and CA1 pyramidal neuronal death after transient global ischemia
Transient ischemia is a leading cause of cognitive dysfunction. Postischemic ROS generation and an increase in the cytosolic Zn²⁺ level ([Zn²⁺]c) are critical in delayed CA1 pyramidal neuronal death, but the underlying mechanisms are not fully understood. Here we investigated the role of ROS-sensitive TRPM2 (transient receptor potential melastatin-related 2) channel. Using in vivo and in vitro models of ischemia-reperfusion, we showed that genetic knockout of TRPM2 strongly prohibited the delayed increase in the [Zn²⁺]c, ROS generation, CA1 pyramidal neuronal death and postischemic memory impairment. Time-lapse imaging revealed that TRPM2 deficiency had no effect on the ischemia-induced increase in the [Zn²⁺]c but abolished the cytosolic Zn²⁺ accumulation during reperfusion as well as ROS-elicited increases in the [Zn²⁺]c. These results provide the first evidence to show a critical role for TRPM2 channel activation during reperfusion in the delayed increase in the [Zn²⁺]c and CA1 pyramidal neuronal death and identify TRPM2 as a key molecule signaling ROS generation to postischemic brain injury
The Winchcombe meteorite, a unique and pristine witness from the outer solar system.
Direct links between carbonaceous chondrites and their parent bodies in the solar system are rare. The Winchcombe meteorite is the most accurately recorded carbonaceous chondrite fall. Its pre-atmospheric orbit and cosmic-ray exposure age confirm that it arrived on Earth shortly after ejection from a primitive asteroid. Recovered only hours after falling, the composition of the Winchcombe meteorite is largely unmodified by the terrestrial environment. It contains abundant hydrated silicates formed during fluid-rock reactions, and carbon- and nitrogen-bearing organic matter including soluble protein amino acids. The near-pristine hydrogen isotopic composition of the Winchcombe meteorite is comparable to the terrestrial hydrosphere, providing further evidence that volatile-rich carbonaceous asteroids played an important role in the origin of Earth's water
Nurse prescribing of medicines in Western European and Anglo-Saxon countries: a systematic review of the literature
<p>Abstract</p> <p>Background</p> <p>A growing number of countries are introducing some form of nurse prescribing. However, international reviews concerning nurse prescribing are scarce and lack a systematic and theoretical approach. The aim of this review was twofold: firstly, to gain insight into the scientific and professional literature describing the extent to and the ways in which nurse prescribing has been realised or is being introduced in Western European and Anglo-Saxon countries; secondly, to identify possible mechanisms underlying the introduction and organisation of nurse prescribing on the basis of Abbott's theory on the division of professional labor.</p> <p>Methods</p> <p>A comprehensive search of six literature databases and seven websites was performed without any limitation as to date of publication, language or country. Additionally, experts in the field of nurse prescribing were consulted. A three stage inclusion process, consisting of initial sifting, more detailed selection and checking full-text publications, was performed independently by pairs of reviewers. Data were synthesized using narrative and tabular methods.</p> <p>Results</p> <p>One hundred and twenty-four publications met the inclusion criteria. So far, seven Western European and Anglo-Saxon countries have implemented nurse prescribing of medicines, viz., Australia, Canada, Ireland, New Zealand, Sweden, the UK and the USA. The Netherlands and Spain are in the process of introducing nurse prescribing. A diversity of external and internal forces has led to the introduction of nurse prescribing internationally. The legal, educational and organizational conditions under which nurses prescribe medicines vary considerably between countries; from situations where nurses prescribe independently to situations in which prescribing by nurses is only allowed under strict conditions and supervision of physicians.</p> <p>Conclusions</p> <p>Differences between countries are reflected in the jurisdictional settlements between the nursing and medical professions concerning prescribing. In some countries, nurses share (full) jurisdiction with the medical profession, whereas in other countries nurses prescribe in a subordinate position. In most countries the jurisdiction over prescribing remains predominantly with the medical profession. There seems to be a mechanism linking the jurisdictional settlements between professions with the forces that led to the introduction of nurse prescribing. Forces focussing on efficiency appear to lead to more extensive prescribing rights.</p
Valorisation of Biowastes for the Production of Green Materials Using Chemical Methods
With crude oil reserves dwindling, the hunt for a sustainable alternative feedstock for fuels and materials for our society continues to expand. The biorefinery concept has enjoyed both a surge in popularity and also vocal opposition to the idea of diverting food-grade land and crops for this purpose. The idea of using the inevitable wastes arising from biomass processing, particularly farming and food production, is, therefore, gaining more attention as the feedstock for the biorefinery. For the three main components of biomass—carbohydrates, lipids, and proteins—there are long-established processes for using some of these by-products. However, the recent advances in chemical technologies are expanding both the feedstocks available for processing and the products that be obtained. Herein, this review presents some of the more recent developments in processing these molecules for green materials, as well as case studies that bring these technologies and materials together into final products for applied usage
Training programme designs in professional team sport: an ecological dynamics exemplar
Ecological dynamics is a contemporary theory of skill acquisition, advocating the mutuality of the performer-environment system, with clear implications for the design of innovative training environments in elite sport. It contends that performance behaviours emerge, and are adapted, by athletes satisfying a confluence of constraints impacting on their structural and functional capacities, the physics of a performance environment and the intended task goals. This framework implicates contemporary models of coaching, training design and sport science support, to stimulate continuous interactions between an individual and performance environment, predicated on representative learning designs (RLD). While theoretical principles of RLD in ecological dynamics are tangible, their practical application in elite and high level (team) sports need verification. Here, we exemplify how data sampled from a high-performance team sport setting could underpin innovative methodologies to support practitioners in designing representative training activities. We highlight how the use of principles grounded within ecological dynamics, along with data from performance analytics, could suggest contemporary models of coaching and preparation for performance in elite sport
Penile hygiene: puberty, paraphimosis and personal care for men and boys with an intellectual disability
Background: Supporting men and boys with an intellectual disability (ID) to meet their penile hygiene needs is perhaps one of the least acknowledged but most confronting issues facing care staff. The delivery of intimate hygiene can be a challenging topic particularly as it has been drawn into the emerging sexuality discourse and the ongoing abuse narrative. Compounding this challenge is the lack of guidance in intimate care for support staff. In addition, whereas the male with an ID outnumber the female, female care staff greatly outnumber male staff. Whether this situation affects outcomes for men and boys with an ID is unknown but it is an issue which should be examined. Method: This paper reports data from two separate studies, one quantitative the other qualitative, which sought to explore penile hygiene as a male health issue. Results: Results show the practice of care staff to be inconsistent, the views and values of care staff to be divergent. Some patterns and contextual differences were identified depending upon the gender of care staff. An emerging dialogue described some of the positive contributions that male staff make to men and boys with an ID. Conclusions: The penile health needs of men and boys with an ID are being compromised by a lack of guidance, training, knowledge and limited gender-sensitive care
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