Co2 efflux, co2 concentration and photosynthetic refixation in stems of Eucalyptus globulus (Labill.)

Research PaperIn spite of the importance of respiration in forest carbon budgets, the mechanisms by which physiological factors control stem respiration are unclear. An experiment was set up in a Eucalyptus globulus plantation in central Portugal with monoculture stands of 5-year-old and 10-year-old trees. CO2 efflux from stems under shaded and unshaded conditions, as well as the concentration of CO2 dissolved in sap [CO2 *], stem temperature, and sap flow were measured with the objective of improving our understanding of the factors controlling CO2 release from stems of E. globulus. CO2 efflux was consistently higher in 5-year-old, compared with 10-year-old, stems, averaging 3.4 versus 1.3 mmol m22 s21, respectively. Temperature and [CO2 *] both had important, and similar, influences on the rate of CO2 efflux from the stems, but neither explained the difference in the magnitude of CO2 efflux between trees of different age and size. No relationship was found between efflux and sap flow, and efflux was independent of tree volume, suggesting the presence of substantial barriers to the diffusion of CO2 from the xylem to the atmosphere in this species. The rate of corticular photosynthesis was the same in trees of both ages and only reduced CO2 efflux by 7%, probably due to the low irradiance at the stem surface below the canopy. The younger trees were growing at a much faster rate than the older trees. The difference between CO2 efflux from the younger and older stems appears to have resulted from a difference in growth respiration rather than a difference in the rate of diffusion of xylemtransported CO

Using the Mass Media

Patterns of media use in an urban setting are related to media gratification processes, but the relationship of media use to the needs of the media users is a complex one. Television, newspapers, and books are perceived as the most helpful media sources of need gratification, while radio, magazines, and films are perceived as less helpful. Use of the media is, in general, related to their perceived helpfulness. However, use of the media is not clearly related to the expressed needs of the audience members. The media appear to form two groups, books, magazines, and films as contrasted to radio, television, and newspapers. This dichotomy appears to be based not only on content but on availability and accessibility.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67162/2/10.1177_009365028000700304.pd

Experimental Control and Characterization of Autophagy in Drosophila

Insects such as the fruit fly Drosophila melanogaster, which fundamentally reorganize their body plan during metamorphosis, make extensive use of autophagy for their normal development and physiology. In the fruit fly, the hepatic/adipose organ known as the fat body accumulates nutrient stores during the larval feeding stage. Upon entering metamorphosis, as well as in response to starvation, these nutrients are mobilized through a massive induction of autophagy, providing support to other tissues and organs during periods of nutrient deprivation. High levels of autophagy are also observed in larval tissues destined for elimination, such as the salivary glands and larval gut. Drosophila is emerging as an important system for studying the functions and regulation of autophagy in an in vivo setting. In this chapter we describe reagents and methods for monitoring autophagy in Drosophila, focusing on the larval fat body. We also describe methods for experimentally activating and inhibiting autophagy in this system and discuss the potential for genetic analysis in Drosophila to identify novel genes involved in autophagy

An assessment of the carbon balance of Arctic tundra:Comparisons among observations, process models, and atmospheric inversions

Although Arctic tundra has been estimated to cover only 8% of the global land surface, the large and potentially labile carbon pools currently stored in tundra soils have the potential for large emissions of carbon (C) under a warming climate. These emissions as radiatively active greenhouse gases in the form of both CO<sub>2</sub> and CH<sub>4</sub> could amplify global warming. Given the potential sensitivity of these ecosystems to climate change and the expectation that the Arctic will experience appreciable warming over the next century, it is important to assess whether responses of C exchange in tundra regions are likely to enhance or mitigate warming. In this study we compared analyses of C exchange of Arctic tundra between 1990 and 2006 among observations, regional and global applications of process-based terrestrial biosphere models, and atmospheric inversion models. Syntheses of flux observations and inversion models indicate that the annual exchange of CO<sub>2</sub> between Arctic tundra and the atmosphere has large uncertainties that cannot be distinguished from neutral balance. The mean estimate from an ensemble of process-based model simulations suggests that Arctic tundra has acted as a sink for atmospheric CO<sub>2</sub> in recent decades, but based on the uncertainty estimates it cannot be determined with confidence whether these ecosystems represent a weak or a strong sink. Tundra was 0.6 °C warmer in the 2000s compared to the 1990s. The central estimates of the observations, process-based models, and inversion models each identify stronger sinks in the 2000s compared with the 1990s. Some of the process models indicate that this occurred because net primary production increased more in response to warming than heterotrophic respiration. Similarly, the observations and the applications of regional process-based models suggest that CH<sub>4</sub> emissions from Arctic tundra have increased from the 1990s to 2000s because of the sensitivity of CH<sub>4</sub> emissions to warmer temperatures. Based on our analyses of the estimates from observations, process-based models, and inversion models, we estimate that Arctic tundra was a sink for atmospheric CO<sub>2</sub> of 110 Tg C yr<sup>−1</sup> (uncertainty between a sink of 291 Tg C yr<sup>−1</sup> and a source of 80 Tg C yr<sup>−1</sup>) and a source of CH<sub>4</sub> to the atmosphere of 19 Tg C yr<sup>−1</sup> (uncertainty between sources of 8 and 29 Tg C yr<sup>−1</sup>). The suite of analyses conducted in this study indicate that it is important to reduce uncertainties in the observations, process-based models, and inversions in order to better understand the degree to which Arctic tundra is influencing atmospheric CO<sub>2</sub> and CH<sub>4</sub> concentrations. The reduction of uncertainties can be accomplished through (1) the strategic placement of more CO<sub>2</sub> and CH<sub>4</sub> monitoring stations to reduce uncertainties in inversions, (2) improved observation networks of ground-based measurements of CO<sub>2</sub> and CH<sub>4</sub> exchange to understand exchange in response to disturbance and across gradients of climatic and hydrological variability, and (3) the effective transfer of information from enhanced observation networks into process-based models to improve the simulation of CO<sub>2</sub> and CH<sub>4</sub> exchange from Arctic tundra to the atmosphere

Thinking about growth : a cognitive mapping approach to understanding small business development

School of Managemen

Spin dependent scattering of a domain-wall of controlled size

Magnetoresistance measurements in the CPP geometry have been performed on single electrodeposited Co nanowires exchange biased on one side by a sputtered amorphous GdCo layer. This geometry allows the stabilization of a single domain wall in the Co wire, the thickness of which can be controlled by an external magnetic field. Comparing magnetization, resistivity, and magnetoresistance studies of single Co nanowires, of GdCo layers, and of the coupled system, gives evidence for an additional contribution to the magnetoresistance when the domain wall is compressed by a magnetic field. This contribution is interpreted as the spin dependent scattering within the domain wall when the wall thickness becomes smaller than the spin diffusion length.Comment: 9 pages, 13 figure

Lawyer rankings either do not matter for litigation outcomes or are redundant

I investigate the success of litigants in tax cases in England and Wales between 1996 and 2010. I explore the effect upon success of having better-ranked legal representation, according to rankings of barristers published by Chambers. I find that, for a variety of model specifications, there is no significant positive effect of having better-ranked legal representation. After conducting a sensitivity analysis, I conclude that better-ranked legal representation might have a positive effect on litigation outcomes, but only if better-ranked lawyers receive cases that are substantially more difficult to win. However, if better-ranked lawyers receive substantially more difficult cases, this suggests consumers of legal representation are sophisticated enough to dispense with legal rankings

Population policies and education: exploring the contradictions of neo-liberal globalisation

The world is increasingly characterised by profound income, health and social inequalities (Appadurai, 2000). In recent decades development initiatives aimed at reducing these inequalities have been situated in a context of increasing globalisation with a dominant neo-liberal economic orthodoxy. This paper argues that neo-liberal globalisation contains inherent contradictions regarding choice and uniformity. This is illustrated in this paper through an exploration of the impact of neo-liberal globalisation on population policies and programmes. The dominant neo-liberal economic ideology that has influenced development over the last few decades has often led to alternative global visions being overlooked. Many current population and development debates are characterised by polarised arguments with strongly opposing aims and views. This raises the challenge of finding alternatives situated in more middle ground that both identify and promote the socially positive elements of neo-liberalism and state intervention, but also to limit their worst excesses within the population field and more broadly. This paper concludes with a discussion outling the positive nature of middle ground and other possible alternatives

Racial and Ethnic Differences in Acceptability of Urine and Cervico-Vaginal Sample Self-Collection for HPV-Based Cervical Cancer Screening

Background: We compared women's acceptability of urine and cervico-vaginal sample self-collection for high-risk (oncogenic) human papillomavirus (hrHPV) testing and assessed whether acceptability varied across racial/ethnic groups. Methods: As part of a test accuracy study of urine-based hrHPV testing, we recruited a convenience sample of women 25-65 years of age at two colposcopy clinics in North Carolina between November 2016 and January 2019. After self-collection of urine and cervico-vaginal samples, women completed a questionnaire on the acceptability of the sample collection methods. We coded open-ended questions inductively. All results are presented stratified by racial/ethnic group. Results: We included 410 women (119 Hispanic, 115 non-Hispanic Black, 154 non-Hispanic White, and 22 women with other racial identities). Most women (79%, 95% confidence interval [CI] = 76%-83%) had positive feelings about urine-based hrHPV testing. Women generally preferred urine (78%, 95% CI = 74%-82%) over cervico-vaginal self-collection (18%, 95% CI = 14%-22%), but the degree differed by racial/ethnic group, increasing from 75% in non-Hispanic Black to 82% in Hispanic women (p = 0.011). Most women reported at least one positive aspect of urine (89%) and cervico-vaginal self-collection (85%) for hrHPV testing with the most common positive aspect being easy sample collection, although 16% of women were concerned about performing the cervico-vaginal self-collection correctly. Conclusions: Self-collection for hrHPV-based cervical cancer screening is highly acceptable to women across different racial/ethnic groups in the United States, and most women in our study would be more likely to attend future cervical cancer screening appointments if screening were urine based. Urine-based hrHPV testing is a promising approach to improve cervical cancer screening coverage

The Clinical Sequencing Evidence-Generating Research Consortium: Integrating Genomic Sequencing in Diverse and Medically Underserved Populations

The Clinical Sequencing Evidence-Generating Research (CSER) consortium, now in its second funding cycle, is investigating the effectiveness of integrating genomic (exome or genome) sequencing into the clinical care of diverse and medically underserved individuals in a variety of healthcare settings and disease states. The consortium comprises a coordinating center, six funded extramural clinical projects, and an ongoing National Human Genome Research Institute (NHGRI) intramural project. Collectively, these projects aim to enroll and sequence over 6,100 participants in four years. At least 60% of participants will be of non-European ancestry or from underserved settings, with the goal of diversifying the populations that are providing an evidence base for genomic medicine. Five of the six clinical projects are enrolling pediatric patients with various phenotypes. One of these five projects is also enrolling couples whose fetus has a structural anomaly, and the sixth project is enrolling adults at risk for hereditary cancer. The ongoing NHGRI intramural project has enrolled primarily healthy adults. Goals of the consortium include assessing the clinical utility of genomic sequencing, exploring medical follow up and cascade testing of relatives, and evaluating patient-provider-laboratory level interactions that influence the use of this technology. The findings from the CSER consortium will offer patients, healthcare systems, and policymakers a clearer understanding of the opportunities and challenges of providing genomic medicine in diverse populations and settings, and contribute evidence toward developing best practices for the delivery of clinically useful and cost-effective genomic sequencing in diverse healthcare settings