Treatment of brain tumors in children is associated with abnormal MRS ratios in brain tissue remote from the tumor site.

PURPOSE: Children who have brain tumors are at risk for a variety of treatment-related sequelae, including neuropsychological and cognitive impairment, neurologic deficits, and neuroendocrinologic disturbances. We sought to determine the value of proton MR spectroscopy in assessing brain tissue remote from the tumor site to ascertain the effects of chemotherapy and radiation treatment in these patients. METHODS: Single-voxel proton MR spectra from 70 patients (111 spectra) and 11 healthy volunteers (11 spectra) were analyzed. NAA/Cr, NAA/Cho, and Cho/Cr ratios based on peak areas were obtained from nonneoplastic regions of the frontal lobe. The relationship between MR spectroscopic ratios and treatment was determined. RESULTS: NAA-containing ratios were decreased in patients as compared with control subjects. The presence of gadolinium-based contrast material did not cause significant changes in the ratios as compared with precontrast data. When chemotherapy was a component of a child’s treatment protocol, we found a significant decline in NAA/Cr ratios. Patients who underwent both chemotherapy and radiation therapy showed a trend toward lower NAAcontaining ratios if the chemotherapy was administered before the radiation therapy. Patients receiving whole-brain radiation had a trend toward lower NAA-containing ratios than did those who had only focal tumor treatment. CONCLUSION: In children with brain tumors, MR spectroscopy of brain tissue remote from the tumor reveals treatment-related biochemical changes

Seasonal Influence on Botanical Composition of Plantain, Chicory, White- and Red-Clover Based Herbage Mixes

Use of herb based sward mixes that are productive in different weather conditions could be an effective option to provide feed requirements for finishing lambs year round compared to ryegrass (Lolium perenne L.)/white clover (Trifolium repens L.) sward in New Zealand (Kemp et al., 2010). Herbs such as plantain (Plantago lanceolata L.) and chicory (Cichorium intybus L.) and the legumes such as white clover and red clover (Trifolium pratense L.) as pure swards are known to improve lamb performance compared to ryegrass/white clover. Therefore, there is scope to have herb-clover mixes to enhance post-weaning lamb performance. However, one significant limitation in the use of these herbages is the seasonality of their production. A further issue could be their persistence and poor winter growth (Moloney and Milne, 1993). Botanical composition of a sward mix changes depending on the grazing management system. Herbs such as plantain and chicory are susceptible to winter grazing and treading damage affecting their proportion in a sward mix. A sward’s botanical composition (legumes or grasses, leaf or stem materials, dead matter or weeds) and morphological composition (growth in different seasons), would likely affect the nutrient composition and lamb production (Lambert and Litherland, 2000). Therefore, it is essential to observe potential changes within and across seasons of the botanical composition in herb clover sward mixes

Net Herbage Accumulation Rate (NHAR) of Plantain and Chicory Based Sward Mixes

The managed grasslands of New Zealand have a range of forage species comprising grasses and legumes that can be grown and utilised in a wide range of conditions (Saggar et al., 2007). Perennial ryegrass (Lolium perenne) and white clover (Trifolium repens) are the dominant grass and legume species found in these grasslands (Hodgson et al., 2005; Waghorn and Clark, 2004). Annual pasture production is affected by the soil moisture status, nutrient levels and temperatures (Valantine and Kemp, 2007). Therefore, monthly pasture production can vary from year to year. Net herbage accumulation rate (NHAR) is a measurement of pasture production (Valantine and Kemp, 2007). Net herbage accumulation rate can be used to help with livestock management by determining the carrying capacity of the land. Alternative forages such as plantain (Plantago lanceolata) and chicory (Cichorium intybus) are becoming popular in New Zealand. Kemp et al., (2010) suggested that farmers could achieve „marketable target weight‟ of lambs sooner by feeding a herb and legume mix consisted of plantain, chicory, white clover (Trifolium repens) and red clover (Trifolium pratense) compared to a ryegrass/white clover pasture. However, a significant potential limitation in the use of these herbages is the seasonality of their production. There is a dearth of knowledge on NHAR of these herb-clover mixes. Therefore, the aim of this study was to determine NHAR and NHAR curves for plantain and chicory based sward mixes

Bags, junctions, and networks of BPS and non-BPS defects

We investigate several models of coupled scalar fields that present discrete Z_2, Z_2 x Z_2, Z_3 and other symmetries. These models support topological domain wall solutions of the BPS and non-BPS type. The BPS solutions are stable, but the stability of the non-BPS solutions may depend on the parameters that specify the models. The BPS and non-BPS states give rise to bags, and also to three-junctions that may allow the presence of networks of topological defects. In particular, we show that the non-BPS defects of a specific model that engenders the Z_3 symmetry give rise to a stable regular hexagonal network of domain walls.Comment: Revtex, 16 pages, 6 ps figures; Shorter version to be published in Phys. Rev.

High-resolution temporal profiling of transcripts during Arabidopsis leaf senescence reveals a distinct chronology of processes and regulation

Leaf senescence is an essential developmental process that impacts dramatically on crop yields and involves altered regulation of thousands of genes and many metabolic and signaling pathways, resulting in major changes in the leaf. The regulation of senescence is complex, and although senescence regulatory genes have been characterized, there is little information on how these function in the global control of the process. We used microarray analysis to obtain a highresolution time-course profile of gene expression during development of a single leaf over a 3-week period to senescence. A complex experimental design approach and a combination of methods were used to extract high-quality replicated data and to identify differentially expressed genes. The multiple time points enable the use of highly informative clustering to reveal distinct time points at which signaling and metabolic pathways change. Analysis of motif enrichment, as well as comparison of transcription factor (TF) families showing altered expression over the time course, identify clear groups of TFs active at different stages of leaf development and senescence. These data enable connection of metabolic processes, signaling pathways, and specific TF activity, which will underpin the development of network models to elucidate the process of senescence

Differences in trajectories of quality of life according to type of dementia: 6-year longitudinal findings from the IDEAL programme

Background: People with different types of dementia may have distinct symptoms and experiences that affect their quality of life. This study investigated whether quality of life varied across types of dementia and over time. Methods: The participants were 1555 people with mild-to-moderate dementia and 1327 carers from the IDEAL longitudinal cohort study, recruited from clinical services. As many as possible were followed for up to 6 years. Diagnoses included were Alzheimer’s disease, vascular dementia, mixed Alzheimer’s and vascular dementia, Parkinson’s disease dementia, dementia with Lewy bodies, and frontotemporal dementia. Self- and informant-rated versions of the Quality of Life in Alzheimer’s Disease scale were used. A joint model, incorporating a mixed effects model with random effects and a survival model to account for dropout, was used to examine whether quality of life varied by dementia type at the time of diagnosis and how trajectories changed over time. Results: The strongest associations between dementia type and quality of life were seen around the time of diagnosis. For both self-ratings and informant ratings, people with Parkinson’s disease dementia or dementia with Lewy bodies had lower quality of life scores. Over time there was little change in self-rated scores across all dementia types (− 0.15 points per year). Informant-rated scores declined over time (− 1.63 points per year), with the greatest decline seen in ratings by informants for people with dementia with Lewy bodies (− 2.18 points per year). Conclusions: Self-rated quality of life scores were relatively stable over time whilst informant ratings showed a steeper decline. People with Parkinson’s disease dementia or dementia with Lewy bodies report particularly low levels of quality of life, indicating the importance of greater attention to the needs of these groups

The Lick AGN Monitoring Project: Broad-Line Region Radii and Black Hole Masses from Reverberation Mapping of Hbeta

We have recently completed a 64-night spectroscopic monitoring campaign at the Lick Observatory 3-m Shane telescope with the aim of measuring the masses of the black holes in 12 nearby (z < 0.05) Seyfert 1 galaxies with expected masses in the range ~10^6-10^7 M_sun and also the well-studied nearby active galactic nucleus (AGN) NGC 5548. Nine of the objects in the sample (including NGC 5548) showed optical variability of sufficient strength during the monitoring campaign to allow for a time lag to be measured between the continuum fluctuations and the response to these fluctuations in the broad Hbeta emission. We present here the light curves for the objects in this sample and the subsequent Hbeta time lags for the nine objects where these measurements were possible. The Hbeta lag time is directly related to the size of the broad-line region, and by combining the lag time with the measured width of the Hbeta emission line in the variable part of the spectrum, we determine the virial mass of the central supermassive black hole in these nine AGNs. The absolute calibration of the black hole masses is based on the normalization derived by Onken et al. We also examine the time lag response as a function of velocity across the Hbeta line profile for six of the AGNs. The analysis of four leads to ambiguous results with relatively flat time lags as a function of velocity. However, SBS 1116+583A exhibits a symmetric time lag response around the line center reminiscent of simple models for circularly orbiting broad-line region (BLR) clouds, and Arp 151 shows an asymmetric profile that is most easily explained by a simple gravitational infall model. Further investigation will be necessary to fully understand the constraints placed on physical models of the BLR by the velocity-resolved response in these objects.Comment: 24 pages, 16 figures and 13 tables, submitted to Ap