201 research outputs found
The effects of baryon physics, black holes and AGN feedback on the mass distribution in clusters of galaxies
The spatial distribution of matter in clusters of galaxies is mainly
determined by the dominant dark matter component, however, physical processes
involving baryonic matter are able to modify it significantly. We analyse a set
of 500 pc resolution cosmological simulations of a cluster of galaxies with
mass comparable to Virgo, performed with the AMR code RAMSES. We compare the
mass density profiles of the dark, stellar and gaseous matter components of the
cluster that result from different assumptions for the subgrid baryonic physics
and galaxy formation processes. First, the prediction of a gravity only N-body
simulation is compared to that of a hydrodynamical simulation with standard
galaxy formation recipes, then all results are compared to a hydrodynamical
simulation which includes thermal AGN feedback from Super Massive Black Holes
(SMBH). We find the usual effects of overcooling and adiabatic contraction in
the run with standard galaxy formation physics, but very different results are
found when implementing SMBHs and AGN feedback. Star formation is strongly
quenched, producing lower stellar densities throughout the cluster, and much
less cold gas is available for star formation at low redshifts. At redshift z =
0 we find a flat density core of radius 10 kpc in both of the dark and stellar
matter density profiles. We specu- late on the possible formation mechanisms
able to produce such cores and we conclude that they can be produced through
the coupling of different processes: (I) dynamical friction from the decay of
black hole orbits during galaxy mergers; (II) AGN driven gas outflows producing
fluctuations of the gravitational potential causing the removal of
collisionless matter from the central region of the cluster; (III) adiabatic
expansion in response to the slow expulsion of gas from the central region of
the cluster during the quiescent mode of AGN activity.Comment: Published on MNRAS - 13 pages, 4 tables, 9 figure
Vitamin D status in post-medieval Northern England: Insights from dental histology and enamel peptide analysis at Coach Lane, North Shields (AD 1711â1857)
Objectives: The post-medieval period in Europe saw a dramatic increase in metabolic bone disease related to vitamin D deficiency (VDD). Recent paleopathological work has utilized interglobular dentin (IGD) as a proxy for poor vitamin D status during development, while enamel peptide analysis allows the identification of chromosomal sex in non-adult remains. Here we explore the relationship between sex, the presence of IGD, and macroscopic markers of VDD in an industrial era assemblage from Northeast England. Materials and methods: 25 individuals (9 females, 9 males, 9 unknown sex) from the cemetery site at Coach Lane, North Shields (1711â1857) were selected for paleopathological analysis, histological assessment of IGD, and enamel peptide determination of chromosomal sex. Results: Ground tooth sections from 21 individuals were of suitable quality for detection of IGD, and enamel peptide analysis confirmed the chromosomal sex of ten individuals. Sixteen individuals (76.1%) exhibited â„1 episode of IGD. Nine of these (42.8%) exhibited >1 episode and four (19%) exhibited â„4 episodes in regular intervals. Male sex was significantly associated with the presence of IGD (p = 0.0351; 100% males vs. 54.5% females). Females were more likely to exhibit macroscopic evidence of VDD (45.5% females vs 30% males) but this was not statistically significant. Discussion and conclusions: Periods of poor mineral metabolism during childhood appear much more prevalent at Coach Lane than macroscopic evidence suggests. Evidence of seasonal IGD episodes indicates that northern latitude played a major role in poor VD status in the Northeast of England. The significant association of IGD with male sex may be due to sex-related differences in dentinal mineralization or a higher risk of poor VD status in males aged <5 years. More work is needed to establish an evidence-based threshold for pathological levels of IGD before the presence of this feature can confidently be used as a biomarker for poor VD status
Vitamin D status in post-medieval Northern England:Insights from dental histology and enamel peptide analysis at Coach Lane, North Shields (AD 1711-1857)
Objectives The post-medieval period in Europe saw a dramatic increase in metabolic bone disease related to vitamin D deficiency (VDD). Recent paleopathological work has utilized interglobular dentin (IGD) as a proxy for poor vitamin D status during development, while enamel peptide analysis allows the identification of chromosomal sex in non-adult remains. Here we explore the relationship between sex, the presence of IGD, and macroscopic markers of VDD in an industrial era assemblage from Northeast England. Materials and methods 25 individuals (9 females, 9 males, 9 unknown sex) from the cemetery site at Coach Lane, North Shields (1711-1857) were selected for paleopathological analysis, histological assessment of IGD, and enamel peptide determination of chromosomal sex. Results Ground tooth sections from 21 individuals were of suitable quality for detection of IGD, and enamel peptide analysis confirmed the chromosomal sex of ten individuals. Sixteen individuals (76.1%) exhibited â„1 episode of IGD. Nine of these (42.8%) exhibited >1 episode and four (19%) exhibited â„4 episodes in regular intervals. Male sex was significantly associated with the presence of IGD (p = 0.0351; 100% males vs. 54.5% females). Females were more likely to exhibit macroscopic evidence of VDD (45.5% females vs 30% males) but this was not statistically significant. Discussion and conclusions Periods of poor mineral metabolism during childhood appear much more prevalent at Coach Lane than macroscopic evidence suggests. Evidence of seasonal IGD episodes indicates that northern latitude played a major role in poor VD status in the Northeast of England. The significant association of IGD with male sex may be due to sex-related differences in dentinal mineralization or a higher risk of poor VD status in males aged <5 years. More work is needed to establish an evidence-based threshold for pathological levels of IGD before the presence of this feature can confidently be used as a biomarker for poor VD status.</p
Persistent Polypharmacy and Fall Injury Risk: The Health, Aging and Body Composition Study
Background
Older adults receive treatment for fall injuries in both inpatient and outpatient settings. The effect of persistent polypharmacy (i.e. using multiple medications over a long period) on fall injuries is understudied, particularly for outpatient injuries. We examined the association between persistent polypharmacy and treated fall injury risk from inpatient and outpatient settings in community-dwelling older adults.
Methods
The Health, Aging and Body Composition Study included 1764 community-dwelling adults (age 73.6â±â2.9âyears; 52% women; 38% black) with Medicare Fee-For-Service (FFS) claims at or within 6âmonths after 1998/99 clinic visit. Incident fall injuries (N =â545 in 4.6â±â2.9âyears) were defined as the initial claim with an ICD-9 fall E-code and non-fracture injury, or fracture code with/without a fall code from 1998/99 clinic visit to 12/31/08. Those without fall injury (N =â1219) were followed for 8.1â±â2.6âyears. Stepwise Cox models of fall injury risk with a time-varying variable for persistent polypharmacy (defined as â„6 prescription medications at the two most recent consecutive clinic visits) were adjusted for demographics, lifestyle characteristics, chronic conditions, and functional ability. Sensitivity analyses explored if persistent polypharmacy both with and without fall risk increasing drugs (FRID) use were similarly associated with fall injury risk.
Results
Among 1764 participants, 636 (36%) had persistent polypharmacy over the follow-up period, and 1128 (64%) did not. Fall injury incidence was 38 per 1000 person-years. Persistent polypharmacy increased fall injury risk (hazard ratio [HR]: 1.31 [1.06, 1.63]) after adjusting for covariates. Persistent polypharmacy with FRID use was associated with a 48% increase in fall injury risk (95%CI: 1.10, 2.00) vs. those who had non-persistent polypharmacy without FRID use. Risks for persistent polypharmacy without FRID use (HR: 1.22 [0.93, 1.60]) and non-persistent polypharmacy with FRID use (HR: 1.08 [0.77, 1.51]) did not significantly increase compared to non-persistent polypharmacy without FRID use.
Conclusions
Persistent polypharmacy, particularly combined with FRID use, was associated with increased risk for treated fall injuries from inpatient and outpatient settings. Clinicians may need to consider medication management for FRID and other fall prevention strategies in community-dwelling older adults with persistent polypharmacy to reduce fall injury risk
Astrocytic Ion Dynamics: Implications for Potassium Buffering and Liquid Flow
We review modeling of astrocyte ion dynamics with a specific focus on the
implications of so-called spatial potassium buffering, where excess potassium
in the extracellular space (ECS) is transported away to prevent pathological
neural spiking. The recently introduced Kirchoff-Nernst-Planck (KNP) scheme for
modeling ion dynamics in astrocytes (and brain tissue in general) is outlined
and used to study such spatial buffering. We next describe how the ion dynamics
of astrocytes may regulate microscopic liquid flow by osmotic effects and how
such microscopic flow can be linked to whole-brain macroscopic flow. We thus
include the key elements in a putative multiscale theory with astrocytes
linking neural activity on a microscopic scale to macroscopic fluid flow.Comment: 27 pages, 7 figure
Association of Accelerometry-Measured Physical Activity and Cardiovascular Events in Mobility-Limited Older Adults: The LIFE (Lifestyle Interventions and Independence for Elders) Study.
BACKGROUND:Data are sparse regarding the value of physical activity (PA) surveillance among older adults-particularly among those with mobility limitations. The objective of this study was to examine longitudinal associations between objectively measured daily PA and the incidence of cardiovascular events among older adults in the LIFE (Lifestyle Interventions and Independence for Elders) study. METHODS AND RESULTS:Cardiovascular events were adjudicated based on medical records review, and cardiovascular risk factors were controlled for in the analysis. Home-based activity data were collected by hip-worn accelerometers at baseline and at 6, 12, and 24 months postrandomization to either a physical activity or health education intervention. LIFE study participants (n=1590; age 78.9±5.2 [SD] years; 67.2% women) at baseline had an 11% lower incidence of experiencing a subsequent cardiovascular event per 500 steps taken per day based on activity data (hazard ratio, 0.89; 95% confidence interval, 0.84-0.96; P=0.001). At baseline, every 30 minutes spent performing activities â„500 counts per minute (hazard ratio, 0.75; confidence interval, 0.65-0.89 [P=0.001]) were also associated with a lower incidence of cardiovascular events. Throughout follow-up (6, 12, and 24 months), both the number of steps per day (per 500 steps; hazard ratio, 0.90, confidence interval, 0.85-0.96 [P=0.001]) and duration of activity â„500 counts per minute (per 30 minutes; hazard ratio, 0.76; confidence interval, 0.63-0.90 [P=0.002]) were significantly associated with lower cardiovascular event rates. CONCLUSIONS:Objective measurements of physical activity via accelerometry were associated with cardiovascular events among older adults with limited mobility (summary score >10 on the Short Physical Performance Battery) both using baseline and longitudinal data. CLINICAL TRIAL REGISTRATION:URL: http://www.clinicaltrials.gov. Unique identifier: NCT01072500
The emotional context of self-management in chronic illness: A qualitative study of the role of health professional support in the self-management of type 2 diabetes
Background: Support for patient self-management is an accepted role for health professionals. Little evidence exists on the appropriate basis for the role of health professionals in achieving optimum self-management outcomes. This study explores the perceptions of people with type 2 diabetes about their self-management strategies and how relationships with health professionals may support this.Methods: Four focus groups were conducted with people with type 2 diabetes: two with English speaking and one each with Turkish and Arabic-speaking. Transcripts from the groups were analysed drawing on grounded hermeneutics and interpretive description.Results: We describe three conceptually linked categories of text from the focus groups based on emotional context of self management, dominant approaches to self management and support from health professionals for self management. All groups described important emotional contexts to living with and self-managing diabetes and these linked closely with how they approached their diabetes management and what they looked for from health professionals. Culture seemed an important influence in shaping these linkages.Conclusion: Our findings suggest people construct their own individual self-management and self-care program, springing from an important emotional base. This is shaped in part by culture and in turn determines the aims each person has in pursuing self-management strategies and the role they make available to health professionals to support them. While health professionals\u27 support for self-care strategies will be more congruent with patients\u27 expectations if they explore each person\u27s social, emotional and cultural circumstances, pursuit of improved health outcomes may involve a careful balance between supporting as well as helping shift the emotional constructs surrounding a patient life with diabetes.<br /
Abundance, Distribution, and Activity of Fe(II)-Oxidizing and Fe(III)-Reducing Microorganisms in Hypersaline Sediments of Lake Kasin, Southern Russia
The extreme osmotic conditions prevailing in hypersaline environments result in decreasing metabolic diversity with increasing salinity. Various microbial metabolisms have been shown to occur even at high salinity, including photosynthesis as well as sulfate and nitrate reduction. However, information about anaerobic microbial iron metabolism in hypersaline environments is scarce. We studied the phylogenetic diversity, distribution, and metabolic activity of iron(II)-oxidizing and iron(III)-reducing Bacteria and Archaea in pH-neutral, iron-rich salt lake sediments (Lake Kasin, southern Russia; salinity, 348.6 g liter-1) using a combination of culture-dependent and -independent techniques. 16S rRNA gene clone libraries for Bacteria and Archaea revealed a microbial community composition typical for hypersaline sediments. Most-probable-number counts confirmed the presence of 4.26×102 to 8.32×103 iron(II)-oxidizing Bacteria and 4.16×102 to 2.13×103 iron(III)-reducing microorganisms per gram dry sediment. Microbial iron(III) reduction was detected in the presence of 5 M NaCl, extending the natural habitat boundaries for this important microbial process. Quantitative real-time PCR showed that 16S rRNA gene copy numbers of total Bacteria, total Archaea, and species dominating the iron(III)-reducing enrichment cultures (relatives of Halobaculum gomorrense, Desulfosporosinus lacus, and members of the Bacilli) were highest in an iron oxide-rich sediment layer. Combined with the presented geochemical and mineralogical data, our findings suggest the presence of an active microbial iron cycle at salt concentrations close to the solubility limit of NaCl
Crop Updates 2005 - Cereals
This session covers thirty six papers from different authors:
WHEAT AGRONOMY
1. Optimum sowing time of new wheat varieties in Western Australia, Darshan Sharma, Brenda Shackley, Mohammad Amjad, Christine M. Zaicou-Kunesch and Wal Anderson, Department of Agriculture
2. Wheat varieties updated in âFlowering Calculatorâ: A model predicting flowering time, B. Shackley, D. Tennant, D. Sharma and C.M. Zaicou-Kunesch, Department of Agriculture
3. Plant populations for wheat varieties, Christine M. Zaicou-Kunesch, Wal Anderson, Darshan Sharma, Brenda Shackley and Mohammad Amjad, Department of Agriculture
4. New wheat cultivars response to fertiliser nitrogen in four major agricultural regions of Western Australia, Mohammad Amjad, Wal Anderson, Brenda Shackley, Darshan Sharma and Christine Zaicou-Kunesch, Department of Agriculture
5. Agronomic package for EGA Eagle Rock, Steve Penny, Department of Agriculture
6. Field evaluation of eastern and western wheats in large-scale farmerâs trials, Mohammad Amjad, Ben Curtis and Veronika Reck, Department of Agriculture
7. New wheat varieties for a changing environment, Richard Richards, CSIRO Plant Industry; Canberra
8. Farmers can profitably minimise exposure to frost! Garren Knell, Steve Curtin and David Sermon, ConsultAg
9. National Variety Trials, Alan Bedggood, Australian Crops Accreditation System; Horsham
10. Preharvest-sprouting tolerance of wheat in the field, T.B. Biddulph1, T.L. Setter2, J.A. Plummer1 and D.J. Mares3; 1Plant Biology; FNAS, University of Western Australia; 2Department of Agriculture, 3School of Agriculture and Wine, University of Adelaide
11. Waterlogging induces high concentration of Mn and Al in wheat genotypes in acidic soils, H. Khabaz-Saberi, T. Setter, I. Waters and G. McDonald, Department of Agriculture
12. Agronomic responses of new wheat varieties in the Northern Agricultural Region, Christine M. Zaicou-Kunesch and Wal Anderson, Department of Agriculture
13. Agronomic responses of new wheat varieties in the Central Agricultural Region of WA, Darshan Sharma, Steve Penny and Wal Anderson, Department of Agriculture
14. EGA Eagle Rock tolerance to metribuzin and its mixtures, Harmohinder Dhammu, David Nicholson and Chris Roberts, Department of Agriculture
15. Herbicide tolerance of new bread wheats, Harmohinder Dhammu1 and David Nicholson2, Department of Agriculture
NUTRITION
16. The impact of fertiliser placement, timing and rates on nitrogen-use efficiency, Stephen Loss, CSBP Ltd
17. Cereals deficient in potassium are most susceptible to some leaf diseases, Ross Brennan and Kith Jayasena, Department of Agriculture
18. Responses of cereal yields to potassium fertiliser type, placement and timing, Eddy Pol, CSBP Limited
19. Sulphate of Potash, the potash of choice at seeding, Simon Teakle, United Farmers Co-operative
20. Essential disease management for successful barley production, K. Jayasena, R. Loughman, C. Beard, B. Paynter, K. Tanaka, G. Poulish and A. Smith, Department of Agriculture
21. Genotypic differences in potassium efficiency of wheat, Paul Damon and Zed Rengel, Faculty of Natural and Agricultural Sciences, University of Western Australia
22. Genotypic differences in potassium efficiency of barley, Paul Damon and Zed Rengel, Faculty of Natural and Agricultural Sciences, University of Western Australia
23. Investigating timing of nitrogen application in wheat, Darshan Sharma and Lionel Martin, Department of Agriculture, and Muresk Institute of Agriculture, Curtin University of Technology
24. Nutrient timing requirements for increased crop yields in the high rainfall cropping zone, Narelle Hill, Ron McTaggart, Dr Wal Anderson and Ray Tugwell, Department of Agriculture
DISEASES
25. Integrate strategies to manage stripe rust risk, Geoff Thomas, Robert Loughman, Ciara Beard, Kith Jayasena and Manisha Shankar, Department of Agriculture
26. Effect of primary inoculum level of stripe rust on variety response in wheat, Manisha Shankar, John Majewski and Robert Loughman, Department of Agriculture
27. Disease resistance update for wheat varieties in WA, M. Shankar, J.M. Majewski, D. Foster, H. Golzar, J. Piotrowski and R. Loughman, Department of Agriculture
28. Big droplets for wheat fungicides, Rob Grima, Agronomist, Elders
29. On farm research to investigate fungicide applications to minimise leaf disease impacts in wheat, Jeff Russell and Angie Roe, Department of Agriculture, and Farm Focus Consultants
PESTS
30. Rotations for nematode management, Vivien A. Vanstone, Sean J. Kelly, Helen F. Hunter and Mena C. Gilchrist, Department of Agriculture
31. Investigation into the adaqyacy of sealed farm silos in Western Australia to control phosphine-resistant Rhyzopertha dominica, C.R. Newman, Department of Agriculture
32.Insect contamination of cereal grain at harvest, Svetlana Micic and Phil Michael, Department of Agriculture
33. Phosure â Extending the life of phosphine, Gabrielle Coupland and Ern Kostas, Co-operative Bulk Handling
SOIL
34. Optimum combinations of ripping depth and tine spacing for increasing wheat yield, Mohammed Hamza and Wal Anderson, Department of Agriculture
35. Hardpan penetration ability of wheat roots, Tina Botwright Acuña and Len Wade, School of Plant Biology, University of Western Australia
MARKETS
36. Latin America: An emerging agricultural powerhouse, Ingrid Richardson, Food and Agribusiness Research, Rabobank; Sydne
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