Cumulus cloud venting of mixed layer ozone

Observations are presented which substantiate the hypothesis that significant vertical exchange of ozone and aerosols occurs between the mixed layer and the free troposphere during cumulus cloud convective activity. The experiments utilized the airborne Ultra-Violet Differential Absorption Lidar (UV-DIAL) system. This system provides simultaneous range resolved ozone concentration and aerosol backscatter profiles with high spatial resolution. Evening transects were obtained in the downwind area where the air mass had been advected. Space-height analyses for the evening flight show the cloud debris as patterns of ozone typically in excess of the ambient free tropospheric background. This ozone excess was approximately the value of the concentration difference between the mixed layer and free troposphere determined from independent vertical soundings made by another aircraft in the afternoon

Mechanical response of neural cells to physiologically relevant stiffness gradients

Understanding the influence of the mechanical environment on neurite behavior is crucial in the development of peripheral nerve repair solutions, and could help tissue engineers to direct and guide regeneration. In this study, a new protocol to fabricate physiologically relevant hydrogel substrates with controlled mechanical cues is proposed. These hydrogels allow the analysis of the relative effects of both the absolute stiffness value and the local stiffness gradient on neural cell behavior, particularly for low stiffness values (1–2 kPa). NG108‐15 neural cell behavior is studied using well‐characterized collagen gradient substrates with stiffness values ranging from 1 to 10 kPa and gradient slopes of either 0.84 or 7.9 kPa mm^{-1}. It is found that cell orientation is influenced by specific combinations of stiffness value and stiffness gradient. The results highlight the importance of considering the type of hydrogel as well as both the absolute value of the stiffness and the steepness of its gradient, thus introducing a new framework for the development of tissue engineered scaffolds and the study of substrate stiffness

Long-term adherence to healthy dietary guidelines and chronic inflammation in the prospective Whitehall II study

Background Inflammation plays an important role in the cause of cardiovascular diseases and may contribute to the association linking an unhealthy diet to chronic age-related diseases. However, to date the long-term associations between diet and inflammation have been poorly described. Our aim was to assess the extent to which adherence to a healthy diet and dietary improvements over a 6-year exposure period prevented subsequent chronic inflammation over a 5-year follow-up in a large British population of men and women. Methods Data were drawn from 4600 adults (mean ± standard deviation, age 49.6 ± 6.1 years, 28% were women) from the prospective Whitehall cohort II study. Adherence to a healthy diet was measured using Alternative Healthy Eating Index (AHEI) scores in 1991-1993 (50.7 ± 11.9 points) and 1997-1999 (51.6 ± 12.4 points). Chronic inflammation, defined as average levels of serum interleukin-6 from 2 measures 5 years apart, was assessed in 1997-1999 and 2002-2004. Results After adjustment for sociodemographic factors, health behaviors, and health status, participants who maintained a high AHEI score (ie, a healthy diet, n = 1736, 37.7%) and those who improved this score over time (n = 681, 14.8%) showed significantly lower mean levels of interleukin-6 (1.84 pg/mL, 95% confidence interval [CI], 1.71-1.98 and 1.84 pg/mL, 95% CI, 1.70-1.99, respectively) than those who had a low AHEI score (n = 1594, 34.6%) over the 6-year exposure period (2.01 pg/mL, 95% CI, 1.87-2.17). Conclusions These data suggest that maintaining and improving adherence to healthy dietary recommendations may reduce the risk of long-term inflammation.</p

The evaluation of a shuttle borne lidar experiment to measure the global distribution of aerosols and their effect on the atmospheric heat budget

A shuttle-borne lidar system is described, which will provide basic data about aerosol distributions for developing climatological models. Topics discussed include: (1) present knowledge of the physical characteristics of desert aerosols and the absorption characteristics of atmospheric gas, (2) radiative heating computations, and (3) general circulation models. The characteristics of a shuttle-borne radar are presented along with some laboratory studies which identify schemes that permit the implementation of a high spectral resolution lidar system

Gender-specific associations of short sleep duration with prevalent and incident hypertension : the Whitehall II Study

Sleep deprivation (5 hour per night) was associated with a higher risk of hypertension in middle-aged American adults but not among older individuals. However, the outcome was based on self-reported diagnosis of incident hypertension, and no gender-specific analyses were included. We examined cross-sectional and prospective associations of sleep duration with prevalent and incident hypertension in a cohort of 10 308 British civil servants aged 35 to 55 years at baseline (phase 1: 1985-1988). Data were gathered from phase 5 (1997-1999) and phase 7 (2003-2004). Sleep duration and other covariates were assessed at phase 5. At both examinations, hypertension was defined as blood pressure 140/90 mm Hg or regular use of antihypertensive medications. In cross-sectional analyses at phase 5 (n5766), short duration of sleep (5 hour per night) was associated with higher risk of hypertension compared with the group sleeping 7 hours, among women (odds ratio: 2.01; 95% CI: 1.13 to 3.58), independent of confounders, with an inverse linear trend across decreasing hours of sleep (P0.003). No association was detected in men. In prospective analyses (mean follow-up: 5 years), the cumulative incidence of hypertension was 20.0% (n740) among 3691 normotensive individuals at phase 5. In women, short duration of sleep was associated with a higher risk of hypertension in a reduced model (age and employment) (6 hours per night: odds ratio: 1.56 [95% CI: 1.07 to 2.27]; 5 hour per night: odds ratio: 1.94 [95% CI: 1.08 to 3.50] versus 7 hours). The associations were attenuated after accounting for cardiovascular risk factors and psychiatric comorbidities (odds ratio: 1.42 [95% CI: 0.94 to 2.16]; odds ratio: 1.31 [95% CI: 0.65 to 2.63], respectively). Sleep deprivation may produce detrimental cardiovascular effects among women. (Hypertension. 2007;50:694-701.) Key Words: sleep duration blood pressure hypertension gender differences confounders comorbiditie

ECT, sleep, and biogenic amines in affective illness

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26148/1/0000225.pd

Application of powder metallurgy techniques to produce improved bearing elements for liquid rocket engines

The objective was to apply powder metallurgy techniques for the production of improved bearing elements, specifically balls and races, for advanced cryogenic turbopump bearings. The materials and fabrication techniques evaluated were judged on the basis of their ability to improve fatigue life, wear resistance, and corrosion resistance of Space Shuttle Main Engine (SSME) propellant bearings over the currently used 440C. An extensive list of candidate bearing alloys in five different categories was considered: tool/die steels, through hardened stainless steels, cobalt-base alloys, and gear steels. Testing of alloys for final consideration included hardness, rolling contact fatigue, cross cylinder wear, elevated temperature wear, room and cryogenic fracture toughness, stress corrosion cracking, and five-ball (rolling-sliding element) testing. Results of the program indicated two alloys that showed promise for improved bearing elements. These alloys were MRC-2001 and X-405. 57mm bearings were fabricated from the MRC-2001 alloy for further actual hardware rig testing by NASA-MSFC

Degree of explanation

Partial explanations are everywhere. That is, explanations citing causes that explain some but not all of an effect are ubiquitous across science, and these in turn rely on the notion of degree of explanation. I argue that current accounts are seriously deficient. In particular, they do not incorporate adequately the way in which a cause’s explanatory importance varies with choice of explanandum. Using influential recent contrastive theories, I develop quantitative definitions that remedy this lacuna, and relate it to existing measures of degree of causation. Among other things, this reveals the precise role here of chance, as well as bearing on the relation between causal explanation and causation itself

Reaction time and incident cancer: 25 years of follow-up of study members in the UK Health and Lifestyle Survey

&lt;b&gt;Objectives&lt;/b&gt;&lt;p&gt;&lt;/p&gt; To investigate the association of reaction time with cancer incidence.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Methods&lt;/b&gt;&lt;p&gt;&lt;/p&gt; 6900 individuals aged 18 to 94 years who participated in the UK Health and Lifestyle Survey in 1984/1985 and were followed for a cancer registration for 25 years.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Results&lt;/b&gt;&lt;p&gt;&lt;/p&gt; Disease surveillance gave rise to 1015 cancer events from all sites. In general, there was essentially no clear pattern of association for either simple or choice reaction time with cancer of all sites combined, nor specific malignancies. However, selected associations were found for lung cancer, colorectal cancer and skin cancer.&lt;p&gt;&lt;/p&gt; &lt;b&gt;Conclusions&lt;/b&gt;&lt;p&gt;&lt;/p&gt; In the present study, reaction time and its components were not generally related to cancer risk