Trophic Conditions and Planktonic Processes of Semi-arid Floodplain Lakes Inundated with Environmental Flows

Shallow floodplain lakes are critical components of semi-arid floodplain wetland systems. Delivery of environmental flows that aim to sustain ecological processes of semi-arid floodplain wetlands has enhanced inundation of shallow lakes in inland Australia. To maximise environmental flow outcomes to support floodplain productivity and ecosystem functions, environmental managers would benefit from knowing whether semi-arid floodplain lakes function as a sink or source of atmospheric carbon. We investigated abiotic conditions, and rates of planktonic respiration and primary productivity of phytoplankton during summer under environmental flow conditions in three floodplain lakes of the lower Murrumbidgee River, Australia. All lakes showed mesoeutrophic to hypereutrophic characteristics and significant within- and between-lake variability in abiotic conditions, planktonic processes, and associated carbon balance. Nevertheless, the mean net primary productivity of phytoplankton in the lakes (364-1,674 mg C m-2 day-1) were up to about three times greater than in other semi-arid floodplain wetlands of southeast Australia. Therefore, shallow floodplain lakes in semi-arid regions have great potential to function as a sink of atmospheric carbon through planktonic metabolism during summer. A spatial hierarchical framework for lake functional response to inundation is proposed to support decision-making and to maximise the benefits of environmental flow regimes for floodplain lakes

Metropolis simulations of Met-Enkephalin with solvent-accessible area parameterizations

We investigate the solvent-accessible area method by means of Metropolis simulations of the brain peptide Met-Enkephalin at 300$K$. For the energy function ECEPP/2 nine atomic solvation parameter (ASP) sets are studied. The simulations are compared with one another, with simulations with a distance dependent electrostatic permittivity $\epsilon (r)$, and with vacuum simulations ($\epsilon =2$). Parallel tempering and the biased Metropolis techniques RM$_1$ are employed and their performance is evaluated. The measured observables include energy and dihedral probability densities (pds), integrated autocorrelation times, and acceptance rates. Two of the ASP sets turn out to be unsuitable for these simulations. For all other systems selected configurations are minimized in search of the global energy minima, which are found for the vacuum and the $\epsilon(r)$ system, but for none of the ASP models. Other observables show a remarkable dependence on the ASPs. In particular, we find three ASP sets for which the autocorrelations at 300$$K are considerably smaller than for vacuum simulations.Comment: 10 pages and 8 figure

Open source approaches to establishing Roseobacter Glade bacteria as synthetic biology chassis for biogeoengineering

AIM: The nascent field of bio-geoengineering stands to benefit from synthetic biologists’ efforts to standardise, and in so doing democratise, biomolecular research methods. Roseobacter clade bacteria comprise 15–20% of oceanic bacterio-plankton communities, making them a prime candidate for establishment of synthetic biology chassis for bio-geoengineering activities such as bioremediation of oceanic waste plastic. Developments such as the increasing affordability of DNA synthesis and laboratory automation continue to foster the establishment of a global ‘do-it-yourself’ research community alongside the more traditional arenas of academe and industry. As a collaborative group of citizen, student and professional scientists we sought to test the following hypotheses: (i) that an incubator capable of cultivating bacterial cells can be constructed entirely from non-laboratory items, (ii) that marine bacteria from the Roseobacter clade can be established as a genetically tractable synthetic biology chassis using plasmids conforming to the BioBrickTM standard and finally, (iii) that identifying and subcloning genes from a Roseobacter clade species can readily by achieved by citizen scientists using open source cloning and bioinformatic tools. METHOD: We cultivated three Roseobacter species, Roseobacter denitrificans, Oceanobulbus indolifexand Dinoroseobacter shibae. For each species we measured chloramphenicol sensitivity, viability over 11 weeks of glycerol-based cryopreservation and tested the effectiveness of a series of electroporation and heat shock protocols for transformation using a variety of plasmid types. We also attempted construction of an incubator-shaker device using only publicly available components. Finally, a subgroup comprising citizen scientists designed and attempted a procedure for isolating the cold resistance anf1 gene from Oceanobulbus indolifexcells and subcloning it into a BioBrickTM formatted plasmid. RESULTS: All species were stable over 11 weeks of glycerol cryopreservation, sensitive to 17 µg/mL chloramphenicol and resistant to transformation using the conditions and plasmids tested. An incubator-shaker device, ‘UCLHack-12’ was assembled and used to cultivate sufficient quantity of Oceanobulbus indolifexcells to enable isolation of the anf1 gene and its subcloning into a plasmid to generate the BioBrickTM BBa_K729016. CONCLUSION: The process of ‘de-skilling’ biomolecular techniques, particularly for relatively under-investigated organisms, is still on-going. However, our successful cell growth and DNA manipulation experiments serve to indicate the types of capabilities that are now available to citizen scientists. Science democratised in this way can make a positive contribution to the debate around the use of bio-geoengineering to address oceanic pollution or climate change

Resonant nonlinear magneto-optical effects in atoms

In this article, we review the history, current status, physical mechanisms, experimental methods, and applications of nonlinear magneto-optical effects in atomic vapors. We begin by describing the pioneering work of Macaluso and Corbino over a century ago on linear magneto-optical effects (in which the properties of the medium do not depend on the light power) in the vicinity of atomic resonances, and contrast these effects with various nonlinear magneto-optical phenomena that have been studied both theoretically and experimentally since the late 1960s. In recent years, the field of nonlinear magneto-optics has experienced a revival of interest that has led to a number of developments, including the observation of ultra-narrow (1-Hz) magneto-optical resonances, applications in sensitive magnetometry, nonlinear magneto-optical tomography, and the possibility of a search for parity- and time-reversal-invariance violation in atoms.Comment: 51 pages, 23 figures, to appear in Rev. Mod. Phys. in Oct. 2002, Figure added, typos corrected, text edited for clarit

Fossils from Mille-Logya, Afar, Ethiopia, elucidate the link between Pliocene environmental changes and Homo origins

Several hypotheses posit a link between the origin of Homo and climatic and environmental shifts between 3 and 2.5 Ma. Here we report on new results that shed light on the interplay between tectonics, basin migration and faunal change on the one hand and the fate of Australopithecus afarensis and the evolution of Homo on the other. Fieldwork at the new Mille-Logya site in the Afar, Ethiopia, dated to between 2.914 and 2.443 Ma, provides geological evidence for the northeast migration of the Hadar Basin, extending the record of this lacustrine basin to Mille-Logya. We have identified three new fossiliferous units, suggesting in situ faunal change within this interval. While the fauna in the older unit is comparable to that at Hadar and Dikika, the younger units contain species that indicate more open conditions along with remains of Homo. This suggests that Homo either emerged from Australopithecus during this interval or dispersed into the region as part of a fauna adapted to more open habitats.info:eu-repo/semantics/publishedVersio

Structural evidence for the partially oxidized dipyrromethene and dipyrromethanone forms of the cofactor of porphobilinogen deaminase: structures of the Bacillus megaterium

The enzyme porphobilinogen deaminase (PBGD; hydroxymethylbilane synthase; EC 2.5.1.61) catalyses an early step of the tetrapyrrole-biosynthesis pathway in which four molecules of the monopyrrole porphobilinogen are condensed to form a linear tetrapyrrole. The enzyme possesses a dipyrromethane cofactor, which is covalently linked by a thioether bridge to an invariant cysteine residue (Cys241 in the Bacillus megaterium enzyme). The cofactor is extended during the reaction by the sequential addition of the four substrate molecules, which are released as a linear tetrapyrrole product. Expression in Escherichia coli of a His-tagged form of B. megaterium PBGD has permitted the X-ray analysis of the enzyme from this species at high resolution, showing that the cofactor becomes progressively oxidized to the dipyrromethene and dipyrromethanone forms. In previously solved PBGD structures, the oxidized cofactor is in the dipyromethenone form, in which both pyrrole rings are approximately coplanar. In contrast, the oxidized cofactor in the B. megaterium enzyme appears to be in the dipyrromethanone form, in which the C atom at the bridging α-position of the outer pyrrole ring is very clearly in a tetrahedral configuration. It is suggested that the pink colour of the freshly purified protein is owing to the presence of the dipyrromethene form of the cofactor which, in the structure reported here, adopts the same conformation as the fully reduced dipyrromethane form

Uncovering treatment burden as a key concept for stroke care: a systematic review of qualitative research

<b>Background</b> Patients with chronic disease may experience complicated management plans requiring significant personal investment. This has been termed ‘treatment burden’ and has been associated with unfavourable outcomes. The aim of this systematic review is to examine the qualitative literature on treatment burden in stroke from the patient perspective.<p></p> <b>Methods and findings</b> The search strategy centred on: stroke, treatment burden, patient experience, and qualitative methods. We searched: Scopus, CINAHL, Embase, Medline, and PsycINFO. We tracked references, footnotes, and citations. Restrictions included: English language, date of publication January 2000 until February 2013. Two reviewers independently carried out the following: paper screening, data extraction, and data analysis. Data were analysed using framework synthesis, as informed by Normalization Process Theory. Sixty-nine papers were included. Treatment burden includes: (1) making sense of stroke management and planning care, (2) interacting with others, (3) enacting management strategies, and (4) reflecting on management. Health care is fragmented, with poor communication between patient and health care providers. Patients report inadequate information provision. Inpatient care is unsatisfactory, with a perceived lack of empathy from professionals and a shortage of stimulating activities on the ward. Discharge services are poorly coordinated, and accessing health and social care in the community is difficult. The study has potential limitations because it was restricted to studies published in English only and data from low-income countries were scarce.<p></p> <b>Conclusions</b> Stroke management is extremely demanding for patients, and treatment burden is influenced by micro and macro organisation of health services. Knowledge deficits mean patients are ill equipped to organise their care and develop coping strategies, making adherence less likely. There is a need to transform the approach to care provision so that services are configured to prioritise patient needs rather than those of health care systems

Antioxidant potential of bitter cumin (Centratherum anthelminticum (L.) Kuntze) seeds in in vitro models

<p>Abstract</p> <p>Background</p> <p>Bitter cumin (<it>Centratherum anthelminticum </it>(L.) Kuntze), is a medicinally important plant. Earlier, we have reported phenolic compounds, antioxidant, and anti-hyperglycemic, antimicrobial activity of bitter cumin. In this study we have further characterized the antioxidative activity of bitter cumin extracts in various in vitro models.</p> <p>Methods</p> <p>Bitter cumin seeds were extracted with a combination of acetone, methanol and water. The antioxidant activity of bitter cumin extracts were characterized in various <it>in vitro </it>model systems such as DPPH radical, ABTS radical scavenging, reducing power, oxidation of liposomes and oxidative damage to DNA.</p> <p>Results</p> <p>The phenolic extracts of bitter cumin at microgram concentration showed significant scavenging of DPPH and ABTS radicals, reduced phosphomolybdenum (Mo(VI) to Mo(V)), ferricyanide Fe(III) to Fe(II), inhibited liposomes oxidation and hydroxyl radical induced damage to prokaryotic genomic DNA. The results showed a direct correlation between phenolic acid content and antioxidant activity.</p> <p>Conclusion</p> <p>Bitter cumin is a good source of natural antioxidants.</p

Application f ionized reactive oxygen species for desinfection of carcasses, table eggs and fertile eggs

Primary Audience: Processing Plant Managers, Hatchery Managers SUMMARY We evaluated the effect of ionized reactive oxygen species created using Binary Ionization Technology (BIT) for disinfection of broiler carcasses, table eggs, and treatment of fertile eggs. Previous research has indicated that BIT creates a high concentration of reactive oxygen species (ROS) that lyse bacterial cells on contact. Application of BIT to broiler carcasses that had been intentionally inoculated with 1.58 × 10 6 Salmonella enterica Enteritidis (SE) caused a 1 to 3 log reduction in recoverable SE, depending on the duration of the treatment. Additionally, after inoculation of table eggs with 6.8 × 10 8 cfu of SE, we recovered SE from 95% fewer eggs following enrichment and found significantly fewer (7.77 and 7.41 log reduction) colony-forming units recovered from eggs treated with BIT compared with nontreated control eggs. We also evaluated whether application of the BIT treatment had any effect on hatchability of broiler breeder eggs to determine whether use of this technology could be feasible in a hatchery environment for disinfection of eggs. There were no significant effects of BIT on the hatchability (of total set) of treated eggs as compared with nontreated control eggs; however, there was a slight numerical increase in hatchability, between 5 and 10% in 2 trials. These data suggest that application of BIT technology to carcasses and table eggs could reduce contamination with pathogens and that the application to fertile eggs may not have effects on hatchability of eggs set

Returning to work after stroke: perspectives of employer stakeholders, a qualitative study.

Purpose: More than 40 % of working age adults with stroke fail to return to work. The work context is a key factor in return to work, but little is known about the experiences of employers in supporting employees with stroke. The aim of this study was to explore return to work after stroke from the employer perspective, to identify key features associated with success and to seek participants’ views regarding the role of healthcare in return to work. Methods: Data was gathered through 18 semi-structured interviews with employer stakeholders and included small business owners, line managers, human resources and occupational health staff. Data was analysed thematically. Results: The main themes identified were: the impact of stroke on the employer, characteristics of the employee, communication, knowledge and information, experience of other stakeholders, integrating healthcare in return to work. Conclusion: Employers face complex emotional and practical issues when helping an employee return to work after stroke, for which many lack knowledge and experience. The range and quality of support networks that they access is variable and advice and support from clinicians is welcomed. Further research is necessary to investigate how such support could be funded and integrated within existing service provision