1,743 research outputs found
A commercial arbuscular mycorrhizal inoculum increases root colonization across wheat cultivars but does not increase assimilation of mycorrhizaâacquired nutrients
Production and heavy application of chemicalâbased fertilizers to maintain crop yields is unsustainable due to pollution from runâoff, high CO2 emissions, and diminishing yield returns. Access to fertilizers will be limited in the future due to rising energy costs and dwindling rock phosphate resources. A growing number of companies produce and sell arbuscular mycorrhizal fungal (AMF) inoculants, intended to help reduce fertilizer usage by facilitating crop nutrient uptake through arbuscular mycorrhizas. However, their success has been variable. Here, we present information about the efficacy of a commercially available AMF inoculant in increasing AMF root colonization and fungal contribution to plant nutrient uptake, which are critical considerations within the growing AMF inoculant industry.
Summary
Arable agriculture needs sustainable solutions to reduce reliance on large inputs of nutrient fertilizers while continuing to improve crop yields. By harnessing arbuscular mycorrhizal symbiosis, there is potential to improve crop nutrient assimilation and growth without additional inputs, although the efficacy of commercially available mycorrhizal inocula in agricultural systems remains controversial.
Using stable and radioisotope tracing, carbonâforânutrient exchange between arbuscular mycorrhizal fungi and three modern cultivars of wheat was quantified in a nonâsterile, agricultural soil, with or without the addition of a commercial mycorrhizal inoculant.
While there was no effect of inoculum addition on aboveâground plant biomass, there was increased root colonization by arbuscular mycorrhizal fungi and changes in community structure. Inoculation increased phosphorus uptake across all wheat cultivars by up to 30%, although this increase was not directly attributable to mycorrhizal fungi. Carbonâforânutrient exchange between symbionts varied substantially between the wheat cultivars.
Plant tissue phosphorus increased in inoculated plants potentially because of changes induced by inoculation in microbial community composition and/or nutrient cycling within the rhizosphere. Our data contribute to the growing consensus that mycorrhizal inoculants could play a role in sustainable food production systems of the future
An Extended Photoperiod Increases Milk Yield and Decreases Ovulatory Activity in Dairy Goats
Short day length is associated with reduced milk production in dairy ruminants. Dairy ruminants have been kept in lit sheds during winter to extend the day length and stimulate milk production. However, there studies are few on the effect of an extended photoperiod on the ensuing reproductive performance of dairy goats. The aim of this study was to examine the effect of long day photoperiod (LDPP) and exposure to bucks on milk production and plasma progesterone and prolactin in dairy goats. The study was conducted in 122 non-pregnant lactating dairy goats over 18 weeks from April to August (late autumn and winter in the Southern Hemisphere). The goats were kept in open sided sheds in which the control treatment received ambient lighting while the LDPP treatment received 16 h of light, including artificial lighting. In June, July and August synchronised does were randomly assigned each month to the presence or absence of a buck and ovulatory activity determined from plasma progesterone. Plasma progesterone concentrations were reduced (0.73 vs. 0.46 pmol, p < 0.001) while prolactin concentrations were increased (0.095 vs. 1.33 ng/mL, p < 0.001) in LDPP goats. The former response was most marked in late winter (0.58 vs. 0.004 pmol, p < 0.001) indicating a lack of functional corpora lutea. While there was no overall effect of buck exposure on plasma progesterone concentrations there was a three-way interaction such that plasma progesterone concentrations were increased (p < 0.05) by exposure to bucks in LDPP goats in August (late winter) but not at other times. Milk production was increased in LDPP goats over the latter stages of the study (1. 55 vs. 1.82 L/d, p < 0.05). Also, persistency of lactation was greater in LDPP goats with fewer goats drying off (13 vs. 0%, p < 0.05). These findings suggest that LDPP can increase milk production and persistence while decreasing ovulatory activity in dairy goats
Functional complementarity of ancient plantâfungal mutualisms: contrasting nitrogen, phosphorus and carbon exchanges between Mucoromycotina and Glomeromycotina fungal symbionts of liverworts
Liverworts, which are amongst the earliest divergent plant lineages and important ecosystem pioneers, often form nutritional mutualisms with arbuscular mycorrhizaâforming Glomeromycotina and fineâroot endophytic Mucoromycotina fungi, both of which coevolved with early land plants. Some liverworts, in common with many later divergent plants, harbour both fungal groups, suggesting these fungi may complementarily improve plant access to different soil nutrients.
We tested this hypothesis by growing liverworts in single and dual fungal partnerships under a modern atmosphere and under 1500 ppm [CO2], as experienced by early land plants. Access to soil nutrients via fungal partners was investigated with 15Nâlabelled algal necromass and 33P orthophosphate. Photosynthate allocation to fungi was traced using 14CO2.
Only Mucoromycotina fungal partners provided liverworts with substantial access to algal 15N, irrespective of atmospheric CO2 concentration. Both symbionts increased 33P uptake, but Glomeromycotina were often more effective. Dual partnerships showed complementarity of nutrient pool use and greatest photosynthate allocation to symbiotic fungi.
We show there are important functional differences between the plantâfungal symbioses tested, providing new insights into the functional biology of Glomeromycotina and Mucoromycotina fungal groups that form symbioses with plants. This may explain the persistence of the two fungal lineages in symbioses across the evolution of land plants
Revisiting Ruddick: Feminism, pacifism and non-violence
This article explores feminist contentions over pacifism and non-violence in the contextof the Greenham Common Peace Camp in the 1980s and later developments offeminist Just War Theory. We argue that Sara Ruddickâs work puts feminist pacifism, its radical feminist critics and feminist just war theory equally into question. Although Ruddick does not resolve the contestations within feminism over peace, violence and the questions of war, she offers a productive way of holding the tension between them. In our judgment, her work is helpful not only for developing a feminist political response to the threats and temptations of violent strategies but also for thinking through the question of the relation between violence and politics as such
Homeostatic competition drives tumor growth and metastasis nucleation
We propose a mechanism for tumor growth emphasizing the role of homeostatic
regulation and tissue stability. We show that competition between surface and
bulk effects leads to the existence of a critical size that must be overcome by
metastases to reach macroscopic sizes. This property can qualitatively explain
the observed size distributions of metastases, while size-independent growth
rates cannot account for clinical and experimental data. In addition, it
potentially explains the observed preferential growth of metastases on tissue
surfaces and membranes such as the pleural and peritoneal layers, suggests a
mechanism underlying the seed and soil hypothesis introduced by Stephen Paget
in 1889 and yields realistic values for metastatic inefficiency. We propose a
number of key experiments to test these concepts. The homeostatic pressure as
introduced in this work could constitute a quantitative, experimentally
accessible measure for the metastatic potential of early malignant growths.Comment: 13 pages, 11 figures, to be published in the HFSP Journa
Policing the community together: the impact of technology on citizen engagement
Despite broad and often varied underlying definitions, a common theme throughout community and neighbourhood policing strategies establishes the need to target improvements in the relationship and level of engagement between the police and the communities they serve. Community policing approaches have long underpinned a desire to move away from reactive policing models towards those which establish a more proactive philosophy, responsive to the wants and needs of the community. The near ubiquitous proliferation of smartphones and other ICTs (Information and Communication Technologies) means they are often seen as a vector through which initiatives of all kinds can instil a culture of proactive engagement with their respective stakeholder communities. This paper builds upon existing research which suggests that technologies for crime prevention should be designed to support communications and problem-solving rather than used simply as a means to disseminate information, unpacking a number of the core concepts that are considered central to participation and effective engagement; social capital, public participation and social and digital inclusion. Moreover, examples of wider initiatives are comparatively discussed, not just those associated with community policing, which target the engagement of communities through the use of technology, and more specifically mobile applications, before reflecting on the empirical evidence and experiences gleaned through the EU H2020 funded âUNITYâ project, a project that sought to establish effective strategies for engagement between police and citizen communities
Using Social Media for Actionable Disease Surveillance and Outbreak Management: A Systematic Literature Review
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Echinoderms have bilateral tendencies
Echinoderms take many forms of symmetry. Pentameral symmetry is the major
form and the other forms are derived from it. However, the ancestors of
echinoderms, which originated from Cambrian period, were believed to be
bilaterians. Echinoderm larvae are bilateral during their early development.
During embryonic development of starfish and sea urchins, the position and the
developmental sequence of each arm are fixed, implying an auxological
anterior/posterior axis. Starfish also possess the Hox gene cluster, which
controls symmetrical development. Overall, echinoderms are thought to have a
bilateral developmental mechanism and process. In this article, we focused on
adult starfish behaviors to corroborate its bilateral tendency. We weighed
their central disk and each arm to measure the position of the center of
gravity. We then studied their turning-over behavior, crawling behavior and
fleeing behavior statistically to obtain the center of frequency of each
behavior. By joining the center of gravity and each center of frequency, we
obtained three behavioral symmetric planes. These behavioral bilateral
tendencies might be related to the A/P axis during the embryonic development of
the starfish. It is very likely that the adult starfish is, to some extent,
bilaterian because it displays some bilateral propensity and has a definite
behavioral symmetric plane. The remainder of bilateral symmetry may have
benefited echinoderms during their evolution from the Cambrian period to the
present
"A convenient truth": air travel passengers' willingness to pay to offset their CO2 emissions
Several economic reviews demonstrate the substantial costs related to climate
change and consequently call for early action. These reviews, however, have been limited
to measuring âobjectiveâ risks and expected material damage related to climate change. The
âsubjectiveâ perceived risk of climate change and societyâs willingness to pay (WTP) to
avoid these risks are expected to provide an important additional motivation for direct
action. We investigate whether and why air travel passengersâan increasingly important
source of greenhouse gas emissionsâare supportive of measures that increase the cost of
their travel based on the polluter pays principle and compensate the damage caused by their
flight. Compared to the results of the few previous studies that have elicited WTP estimates
for climate policy more generally, our results appear to be at the lower end of the scale,
while a comparison to estimates of the social cost of carbon shows that the average WTP
estimate in this study is close to the estimated marginal damage cost. Although significant
differences are found between travellers from Europe, North America, Asia and the rest of
the world, we show that there exists a substantial demand for climate change mitigation
action. The positive risk premium over and above the expected property damage cost
assessments should be accounted for more explicitly in economic reviews as it will add to
the burden of proof of direct action. Measurements of passenger WTP will help policy
makers to design effective financial instruments aimed at discouraging climate-unfriendly
travel activities as well as to generate funds for the measures directed at climate change
mitigation and adaptation. Based on stated WTP by travellers to offset their greenhouse gas
emissions, funds in the order of magnitude of âŹ23 billion could be generated annually to
finance climate change mitigation activities
Changing Pattern of Esophageal Cancer Incidence in New Mexico: A 30-Year Evaluation
The incidence of esophageal adenocarcinoma has increased over the last 30Â years, especially in non-Hispanic whites (nHw). Recent work indicates an increase in Hispanic Americans (HA). It is important to understand the effect of ethnicity on cancer occurrence over a prolonged interval.
We searched the New Mexico Tumor Registry for all cases of esophageal cancer from 1 January 1973 to 31 December 2002. Inclusion criteria were histologic diagnosis of adenocarcinoma or squamous cell carcinoma, ethnicity and gender. Incidence rates for both were compared among ethnic groups in 5-year intervals.
Nine hundred eighty-eight patients met the criteria. Esophageal adenocarcinoma incidence rates/100,000 population increased significantly over 30Â years; 1973â1977, 0.4 cases; 1978â1982, 0.4 cases; 1983â1987, 0.6 cases; 1988â1992, 1.2 cases, 1993â1997, 1.6 cases and 1998â2002, 2.2 cases; PÂ <Â 0.001. Squamous cell carcinoma incidence rates remained unchanged during the interval. In nHw and HA, adenocarcinoma incidence rates increased significantly during the study period. In all minority groups, squamous cell carcinoma remained the major type.
Esophageal adenocarcinoma incidence among nHw and HA increased from 1973 to 2002 in New Mexico. Squamous cell carcinoma remains predominant in minorities. Ethnicity may influence the histology or indicate an increased risk for certain types of esophageal cancer
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