1,619 research outputs found
Investigating the probable consequences of super absorbent polymer and mycorrhizal fungi to reduce detrimental effects of lead on wheat (Triticum aestivum L.)
ArticleIn many parts of the world, agricultural use of soils is restricted due to heavy metal
contamination. Absorption of heavy metals, such as (Pb), in the tissue of plants increases the
plant’s metabolism and causes physiological disorders or even death. In order to study the
potential of super absorbent polymers (SAP) and mycorrhiza fungi application to mitigate adverse
effects of lead (Pb) on wheat, a greenhouse experiment was conducted. The experiment was setup
as a completely randomized design, with two treatments arranged in a factorial scheme with three
levels of lead (0, 100 and 200 mg per kg soil) and four levels of SAP and mycorrhiza fungi
application (without SAP and mycorrhiza fungi application, SAP application alone, mycorrhiza
fungi application alone, SAP and mycorrhiza fungi application combined). The results showed
that Pb significantly affected all parameters measured of wheat. The Pb-contamination caused a
significantly decreasing in plant height, total dry weight per plant and total chlorophyll contents.
And also, the results indicated that the combined use of superabsorbent and mycorrhiza reduced
the amount of superoxide dismutase enzyme. As well as, our results show that the application of
super absorbent polymer and mycorrhizal fungi seems to be a promising path to reduce
detrimental effects of heavy metal pollution of agricultural soils on plant performance.http://dx.doi.org/10.15159/ar.18.00
Fight to Be Forgotten: Exploring the Efficacy of Data Erasure in Popular Operating Systems
A long history of longitudinal and intercultural research has identified decommissioned storage devices (e.g., USB memory sticks) as a serious privacy and security threat. Sensitive data deleted by previous owners have repeatedly been found on second-hand USB sticks through forensic analysis. Such data breaches are unlikely to occur when data is securely erased, rather than being deleted. Yet, research shows people confusing these two terms. In this paper, we report on an investigation of possible causes for this confusion. We analysed the user interface of two popular operating systems and found: (1) inconsistencies in the language used around delete and erase functions, (2) insecure default options, and (3) unclear or incomprehensible information around delete and erase functions. We discuss how this could result in data controllers becoming non-compliant with a legal obligation for erasure, putting data subjects at risk of accidental data breaches from the decommissioning of storage devices. Finally, we propose improvements to the design of relevant user interface elements and the development of official guidelines for best practice on GDPR compatible data erasure procedures
A tilted grating interferometer for full vector field differential x-ray phase contrast tomography
We report on a setup for differential x-ray phase-contrast imaging and tomography, that measures the full 2D phase-gradient information. The setup uses a simple one-dimensional x-ray grating interferometer, in which the grating structures of the interferometer are oriented at a tilt angle with respect to the sample rotation axis. In such a configuration, the differential phase images from opposing tomography projections can be combined to yield both components of the gradient vector. We show how the refractive index distribution as well as its x, y, and z gradient components can be reconstructed directly from the recorded projection data. The method can equally well be applied at conventional x-ray tube sources, to analyzer based x-ray imaging or neutron imaging. It is demonstrated with measurements of an x-ray phantom and a rat brain using synchrotron radiation
Valley spin polarization by using the extraordinary Rashba effect on silicon
The addition of the valley degree of freedom to a two-dimensional spin-polarized electronic system provides the opportunity to multiply the functionality of next-generation devices. So far, however, such devices have not been realized due to the difficulty to polarize the valleys, which is an indispensable step to activate this degree of freedom. Here we show the formation of 100% spin-polarized valleys by a simple and easy way using the Rashba effect on a system with C-3 symmetry. This polarization, which is much higher than those in ordinary Rashba systems, results in the valleys acting as filters that can suppress the backscattering of spin-charge. The present system is formed on a silicon substrate, and therefore opens a new avenue towards the realization of silicon spintronic devices with high efficiency.X114334Nsciescopu
Electron-correlation effects in appearance-potential spectra of Ni
Spin-resolved and temperature-dependent appearance-potential spectra of
ferromagnetic Nickel are measured and analyzed theoretically. The Lander
self-convolution model which relates the line shape to the unoccupied part of
the local density of states turns out to be insufficient. Electron correlations
and orbitally resolved transition-matrix elements are shown to be essential for
a quantitative agreement between experiment and theory.Comment: LaTeX, 6 pages, 2 eps figures included, Phys. Rev. B (in press
Trolling in asynchronous computer-mediated communication: From user discussions to academic definitions
Whilst computer-mediated communication (CMC) can benefit users by providing quick and easy communication between those separated by time and space, it can also provide varying degrees of anonymity that may encourage a sense of impunity and freedom from being held accountable for
inappropriate online behaviour. As such, CMC is a fertile ground for studying impoliteness, whether it occurs in response to perceived threat (flaming), or as an end in its own right (trolling). Currently, first and secondorder
definitions of terms such as im/politeness (Brown and Levinson 1987; Bousfield 2008; Culpeper 2008; Terkourafi 2008), in-civility (Lakoff 2005), rudeness (Beebe 1995, Kienpointner 1997, 2008), and etiquette (Coulmas 1992), are subject to much discussion and debate, yet the CMC
phenomenon of trolling is not adequately captured by any of these terms. Following Bousfield (in press), Culpeper (2010) and others, this paper suggests that a definition of trolling should be informed first and foremost
by user discussions. Taking examples from a 172-million-word, asynchronous CMC corpus, four interrelated conditions of aggression, deception, disruption, and success are discussed. Finally, a working definition of trolling
is presented
Proliferation of sorted human and rat beta cells
Aims/hypothesis: The aim of the study was to determine whether purified beta cells can replicate in vitro and whether this is enhanced by extracellular matrix (ECM) and growth factors. Methods: Human beta cells were purified by FACS by virtue of their high zinc content using Newport Green, and excluding ductal and dead cells. Rat beta cells were sorted by autofluorescence or using the same method developed for human cells. Cells were plated on poly-l-lysine or ECMs from rat or human bladder carcinoma cells or bovine corneal ECM and incubated in the presence of BrdU with or without growth factors. Results: The newly developed method for sorting human beta cells yields a population containing 91.4 ± 2.8% insulin-positive cells with a low level of spontaneous apoptosis and a robust secretory response to glucose. Beta cells from 8-week-old rats proliferated in culture and this was increased by ECM. Among growth factors, only human growth hormone (hGH) and the glucagon-like peptide-1 analogue liraglutide enhanced proliferation of rat beta cells, with a significant increase on both poly-l-lysine and ECM. By contrast, sorted adult human beta cells from 16 donors aged 48.9 ± 14.3years (range 16-64years) failed to replicate demonstrably in vitro regardless of the substratum or growth factors used. Conclusions/interpretation: These findings indicate that, in our conditions, the fully differentiated human adult insulin-producing beta cell was unable to proliferate in vitro. This has important implications for any attempt to expand cells from pancreases of donors of this age group. By contrast, the rat beta cells used here were able to divide in vitro, and this was enhanced by ECM, hGH and liraglutid
Clinical outcomes for young people with screening-detected and clinically-diagnosed rheumatic heart disease in Fiji.
Echocardiographic screening is under consideration as a disease control strategy for rheumatic heart disease (RHD). However, clinical outcomes of young people with screening-detected RHD are unknown. We aimed to describe the outcomes for a cohort with screening-detected RHD, in comparison to patients with clinically-diagnosed RHD.
A retrospective cohort study included all young people with screening-detected RHD in the Central Division of Fiji in the primary cohort. Screen-negative and clinically-diagnosed comparison groups were matched 1:1 to the primary cohort. Data were collected on mortality, clinical complications and healthcare utilisation from the electronic and paper health records and existing databases.
Seventy participants were included in each group. Demographic characteristics of the groups were similar (median age 11years, 69% female, median follow-up 7years). There were nine (12.9%) RHD-related deaths in the clinically-diagnosed group and one (1.4%) in the screening-detected group (Incident Rate Ratio: 9.6, 95% CI 1.3-420.6). Complications of RHD were observed in 39 (55.7%) clinically-diagnosed cases, four (20%) screening-detected cases and one (1.4%) screen-negative case. There were significant differences in the cumulative complication curves of the groups (p<0.001). Rates of admission and surgery were highest in the clinically-diagnosed group, and higher in the screening-detected than screen-negative group.
Young people with screening-detected RHD have worse health outcomes than screen-negative cases in Fiji. The prognosis of clinically-diagnosed RHD remains poor, with very high mortality and complication rates. Further studies in other settings will inform RHD screening policy. Comprehensive control strategies are required for disease prevention
Family memories in the home: contrasting physical and digital mementos
We carried out fieldwork to characterise and compare physical and digital mementos in the home. Physical mementos are highly valued, heterogeneous and support different types of recollection. Contrary to expectations, we found physical mementos are not purely representational, and can involve appropriating common objects and more idiosyncratic forms. In contrast, digital mementos were initially perceived as less valuable, although participants later reconsidered this. Digital mementos were somewhat limited in function and expression, largely involving representational photos and videos, and infrequently accessed. We explain these digital limitations and conclude with design guidelines for digital mementos, including better techniques for accessing and integrating these into everyday life, allowing them to acquire the symbolic associations and lasting value that characterise their physical counterparts
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