bluuebunny/crossref_metadata_2025 huggingface dataset:
Small mitochondrial ARF (smARF) is located in both the nucleus and cytoplasm, induces cell death, and activates p53 in mouse fibroblasts
Authors: Ueda Yuko , Koya Terutsugu , Yoneda-Kato Noriko , Kato Jun-ya
Published: April 2008

The ARF transcript produces two proteins, the full‐length ARF, p19ARF, and a short mitochondrial version, smARF. To explore the functional difference between the two, we generated GFP‐fused expression vectors for each protein and introduced them into NIH3T3 murine fibroblasts, which sustains a global deletion in the INK4a locus but contains a functional p53 gene. GFP‐p19ARF was located within the nucleolus as previously reported, whereas GFP‐smARF was detected mainly in the nucleoplasm. GFP‐smARF induced cell death although to a slightly lesser extent than p19ARF. GFP‐smARF stabilized p53 thereby inducing expression of the target genes, MDM2 and p21. We suggest that smARF has functions other than mitochondria‐mediated autophagy, and induces p53 expression and cell death via a novel mechanism.
Principles of Anesthesiology
Authors: O'neill Miriam H.
Published: April 2008

PRINCIPLES OF ANESTHESIOLOGY by Vincent J. Collins, 1175 pages, Lea and Febiger, Philadelphia, Pa. Price $35.00.
The Research Process in Nursing
Authors: Fisher Leona M.
Published: April 2008

The Research Process in Nursing, by David J. Fox, Ph.D., and Ruth L. Kelly, R.N., Ed. D., Appleton‐Century‐Crofts, Division of Meredith Publishing Co., New York, 1967, 611 pages. Price $12.95.
Personal, Impersonal, and Interpersonal Relations
Authors: Atkinson Lucy Jo
Published: April 2008

Genevieve Burton R.N., PERSONAL, IMPERSONAL, AND INTERPERSONAL RELATIONS, 2nd Edition, 1964, Springer Publishing Company, New York City, Price $3.75.
The Art of Plain Talk
Authors: Crawford Mabel
Published: April 2008

The Art of Plain Talk by Rudolf Flesch, Ph.D., 210 pages, Harper & Row, New York, 1946, Price $4.95 hardcover, $ paperback.
Hospital Sanitation An Administrative Program
Authors: Atkinson Lucy Jo
Published: April 2008

Hospital Sanitation An Administrative Program, by Bertha Yanis Lilsky, Clissold Publishing Co., Chicago, 1966, 167 pages. Price $10.00.
The Nurse and the Law
Authors: Reeser Frances E.
Published: April 2008

The Nurse and The Law, by Harvey Sarner, B.S., LL.B., 219 pages, W. B. Sounders Company, Philadelphia, London & Toronto, 1968. Price $6.50.
Comprehensive Background for Anesthesiology
Authors: William Marie Sister
Published: April 2008

Comprehensive Background for Anesthesiology by W. Forrest Powell, M.D., 338 pages, Charles C. Thomas, Springfield, Ill. Price $15.75.
Obstetric Nursing Manual and Conference Guide
Authors: Buck Barbara
Published: April 2008

OBSTETRIC NURSING MANUAL AND CONFERENCE GUIDE, by Anne D. Kri‐vacek, R.N., The Macmillan Company, New York, 1965. Price $3.00.
The beneficial effect of the sap ofAcer monoin an animal with low-calcium diet-induced osteoporosis-like symptoms
Authors: Lee Geun-Shik , Byun Hyuk-Soo , Kim Man-Hee , Lee Bo-Mi , Ko Sang-Hwan , Jung Eui-Man , Gwak Ki-Seob , Choi In-Gyu , Kang Ha-Young , Jo Hyun-Jin , Lee Hak-Ju , Jeung Eui-Bae
Published: April 2008

The sap ofAcer monohas been called ‘bone-benefit-water’ in Korea because of its mineral and sugar content. In particular, the calcium concentration of the sap ofA. monois 37·5 times higher than commercial spring water. In the current study, we examined whetherA. monosap could improve or prevent osteoporosis-like symptoms in a mouse model. Male mice (3 weeks old) were fed a low-calcium diet supplemented with 25, 50 or 100 %A. monosap, commercial spring water or a high calcium-containing solution as a beverage for 7 weeks. There were no differences in weekly weight gain and food intake among all the groups. Mice that were given a low-calcium diet supplemented with commercial spring water developed osteoporosis-like symptoms. To assess the effect of sap on osteoporosis-like symptoms, we examined serum calcium concentration, and femur density and length, and carried out a histological examination. Serum calcium levels were significantly lower in mice that received a low-calcium diet supplemented with commercial spring water (the negative control group), and in the 25 % sap group compared to mice fed a normal diet, but were normal in the 50 and 100 % sap and high-calcium solution groups. Femur density and length were significantly reduced in the negative control and 25 % sap groups. These results indicate that a 50 % sap solution can mitigate osteoporosis-like symptoms induced by a low-calcium diet. We also examined the regulation of expression of calcium-processing genes in the duodenum and kidney. DuodenalTRPV6and renalcalbindin-D9kwere up-regulated dose-dependently by sap, and the levels of these factors were higher than those attained in the spring water-treated control. The results demonstrate that the sap ofA. monoameliorates the low bone density induced by a low-calcium diet, most likely by increasing calcium ion absorption.
Effect of a prebiotic mixture on intestinal comfort and general wellbeing in health
Authors: Goetze Oliver , Fruehauf Heiko , Pohl Daniel , Giarrè Marianna , Rochat Florence , Ornstein Kurt , Menne Dieter , Fried Michael , Thumshirn Miriam
Published: April 2008

Specific carbohydrates, i.e. prebiotics such as fructo-oligosaccharide (FOS), are not digested in the small intestine but fermented in the colon. Besides beneficial health effects of an enhanced bifidobacteria population, intestinal gas production resulting from fermentation can induce abdominal symptoms. Partial replacement with slowly fermented acacia gum may attenuate side effects. The aim was to compare the effects of FOS with those of a prebiotic mixture (50 % FOS and 50 % acacia gum; BLEND) and a rapidly absorbed carbohydrate (maltodextrin) on general intestinal wellbeing, abdominal comfort and anorectal sensory function. Twenty volunteers (eight male and twelve female; age 20–37 years) completed this double-blind, randomised study with two cycles of a 2-week run-in phase (10 g maltodextrin) followed by 5 weeks of 10 g FOS or BLEND once daily, separated by a 4-week wash-out interval. Abdominal symptoms and general wellbeing were documented by telephone interview or Internet twice weekly. Rectal sensations were assessed by a visual analogue scale during a rectal barostat test after FOS and BLEND treatment. Both FOS and BLEND induced more side effects than maltodextrin. Belching was more pronounced under FOS compared with BLEND (P = 0·09 for females; P = 0·01 for males), and for self-reported general wellbeing strong sex differences were reported (P = 0·002). Urgency scores during rectal barostat were higher with FOS than BLEND (P = 0·01). Faced with a growing range of supplemented food products, consumers may benefit from prebiotic mixtures which cause fewer abdominal side effects. Sex differences must be taken in consideration when food supplements are used.
Eating behaviours and obesity in the adult population of Spain
Authors: Marín-Guerrero A. C. , Gutiérrez-Fisac J. L. , Guallar-Castillón P. , Banegas J. R. , Rodríguez-Artalejo F.
Published: April 2008

To examine the association between several eating behaviours and obesity, data were taken from a cross-sectional study conducted with 34 974 individuals aged 25–64 years, representative of the non-institutionalised Spanish population. Obesity was defined as BMI ≥ 30 kg/m2. Study associations were summarised with OR obtained from logistic regression, with adjustment for socio-demographic and lifestyle factors. The results showed that those skipping breakfast were more likely to be obese, both in men (OR 1·58; 95 % CI 1·29, 1·93) and women (OR 1·53; 95 % CI 1·15, 2·03). Moreover, obesity was more prevalent in those having only two meals per day than in those having three or four meals in men (OR 1·63; 95 % CI 1·37, 1·95) and women (OR 1·30; 95 % CI 1·05, 1·62). Also, snacking was associated with obesity in women (OR 1·51; 95 % CI 1·17, 1·95). However, no association was observed between obesity and having one or more of the main meals away from home, in either sex. In conclusion, skipping breakfast and eating frequency were associated with obesity. The lack of association between eating away from home and obesity is in contrast to most previous research conducted in Anglo-Saxon countries. Differences in the type of establishment frequented when eating out or in the characteristics of restaurant customers in a Mediterranean population might explain these conflicting results.
The effect of an incremental increase in exercise on appetite, eating behaviour and energy balance in lean men and women feedingad libitum
Authors: Whybrow Stephen , Hughes Darren A. , Ritz Patrick , Johnstone Alexandra M. , Horgan Graham W. , King Neil , Blundell John E. , Stubbs R. James
Published: April 2008

The effects of incremental exercise on appetite, energy intake (EI), expenditure (EE) and balance (EB) in lean men and women were examined. Six men (age 29·7 (sd5·9) years, weight 75·2 (sd15·3) kg, height 1·75 (sd0·11) m) and six women (age 24·7 (sd5·9) years, weight 66·7 (sd9·10) kg, height 1·70 (sd0·09) m) were each studied three times during a 16 d protocol, corresponding to no additional exercise (Nex), moderate-intensity exercise (Mex; 1·5–2·0 MJ/d) and high-intensity exercise (Hex; 3·0–4·0 MJ/d) regimens. Subjects were fed to EB during days 1–2, and during days 3–16 they fedad libitumfrom a medium-fat diet of constant composition. Daily EE, assessed using the doubly labelled water method, was 9·2, 11·6 and 13·7 MJ/d (P < 0·001;sed0·45) for the women and 12·2, 14·0 and 16·7 MJ/d (P = 0·007;sed1·11) for the men on the Nex, Mex and Hex treatments, respectively. EI was 8·3, 8·6 and 9·9 MJ/d (P = 0·118;sed0·72) for the women and 10·6, 11·6 and 12·0 MJ/d (P = 0·031;sed0·47) for the men, respectively. On average, subjects compensated for about 30 % of the exercise-induced energy deficit. However, the degree of compensation varied considerably among individuals. The present study captured the initial compensation in EI for exercise-induced energy deficits. Total compensation would take a matter of weeks.
Co-enzyme Q10, riboflavin and niacin supplementation on alteration of DNA repair enzyme and DNA methylation in breast cancer patients undergoing tamoxifen therapy
Authors: Premkumar Vummidi Giridhar , Yuvaraj Srinivasan , Shanthi Palanivel , Sachdanandam Panchanatham
Published: April 2008

In the present study, eighty-four breast cancer patients were randomized to receive a daily supplement of 100 mg co-enzyme Q10, 10 mg riboflavin and 50 mg niacin (CoRN), one dosage per d along with 10 mg tamoxifen twice per d. A significant increase in poly(ADP-ribose) polymerase levels and disappearance ofRASSF1ADNA methylation patterns were found in patients treated with supplement therapy along with tamoxifen compared to untreated breast cancer patients and tamoxifen alone-treated patients. An increase in DNA repair enzymes and disappearance of DNA methylation patterns attributes to reduction in tumour burden and may suggest good prognosis and efficacy of the treatment.
Predictors of first lifetime episodes of major depression in midlife women
Authors: Bromberger J. T. , Kravitz H. M. , Matthews K. , Youk A. , Brown C. , Feng W.
Published: April 2008

Background

Little is known about factors that predict first lifetime episodes of major depression in middle-aged women. It is not known whether health-related factors and life stress pose more or less of a risk to the onset of clinical depression than does the menopausal transition.

Method

The Structured Clinical Interview for DSM-IV Axis I Disorders (SCID) was used to assess diagnoses of lifetime, annual and current major depression in a community-based sample of premenopausal or early perimenopausal African American and White women. Menstrual cycle characteristics, psychosocial and health-related factors, and blood samples for assay of reproductive hormones were obtained annually. Two hundred and sixty-six women without a history of major depression at baseline constituted the cohort for the current analyses.

Results

Over 7 years of follow-up, 42 (15.8%) women met criteria for a diagnosis of major depression. Frequent vasomotor symptoms (VMS; hot flashes and/or night sweats) (HR 2.14,p=0.03) were a significant predictor of major depression in univariate analyses. After simultaneous adjustment for multiple predictors in Cox proportional hazards analyses, frequent VMS were no longer significant; lifetime history of an anxiety disorder (HR 2.20,p=0.02) and role limitations due to physical health (HR 1.88,p=0.07) at baseline and a very stressful life event (HR 2.25,p=0.04) prior to depression onset predicted a first episode of major depression.

Conclusions

Both earlier (e.g. history of anxiety disorders) and more proximal factors (e.g. life stress) may be more important than VMS in contributing to a first episode of major depression during midlife.
Lifetime course of eating disorders: design and validity testing of a new strategy to define the eating disorders phenotype
Authors: Anderluh M. , Tchanturia K. , Rabe-Hesketh S. , Collier D. , Treasure J.
Published: April 2008

Background

Aetiological studies of eating disorders would benefit from a solution to the problem of instability of eating disorder symptoms. We present an approach to defining an eating disorders phenotype based on the retrospective assessment of lifetime eating disorders symptoms to define a lifetime pattern of illness. We further validate this approach by testing the most common lifetime categories for differences in the prevalence of specific childhood personality traits.

Method

Ninety-seven females participated in this study, 35 with a current diagnosis of restricting anorexia nervosa, 32 with binge/purging subtype of anorexia nervosa and 30 with bulimia nervosa. Subjects were interviewed by a newly developed EATATE Lifetime Diagnostic Interview for a retrospective assessment of the lifetime course of eating disorders symptoms and childhood traits reflecting obsessive–compulsive personality.

Results

The data illustrate the extensive instability of the eating disorders diagnosis. Four most common lifetime diagnostic categories were identified that significantly differ in the prevalence of childhood traits. Perfectionism and rigidity were more common in groups with a longer duration of underweight status, longer episodes of severe food restriction, excessive exercising, and shorter duration of binge eating.

Conclusions

The assessment of lifetime symptoms may produce a more accurate definition of the eating disorders phenotype. Obsessive–compulsive traits in childhood may moderate the course producing longer periods of underweight status. These findings may have important implications for nosology, treatment and future aetiological studies of eating disorders.
group shifts and Bernoulli factors
Authors: BOYLE MIKE , SCHRAUDNER MICHAEL
Published: April 2008

In this paper, a group shift is an expansive action of $\Z ^d$ on a compact metrizable zero-dimensional group by continuous automorphisms. All group shifts factor topologically onto equal-entropy Bernoulli shifts; abelian group shifts factor by continuous group homomorphisms onto canonical equal-entropy Bernoulli group shifts; and completely positive entropy abelian group shifts are weakly algebraically equivalent to these Bernoulli factors. A completely positive entropy group (even vector) shift need not be topologically conjugate to a Bernoulli shift, and the Pinsker factor of a vector shift need not split topologically.
On spectral properties of a family of transfer operators and convergence to stable laws for affine random walks
Authors: GUIVARC’H Y. , LE PAGE EMILE
Published: April 2008

We consider a random walk on the affine group of the real line, we denote by P the corresponding Markov operator on $\mathbb {R}$, and we study the Birkhoff sums associated with its trajectories. We show that, depending on the parameters of the random walk, the normalized Birkhoff sums converge in law to a stable law of exponent α∈ ]0,2[ or to a normal law. The corresponding analysis is based on the spectral properties of two families of associated transfer operators Pt,Tt. The operator Pt is a Fourier operator and is considered here as a perturbation of the Markov operator P=P0 of the random walk. The operator Tt is related to Pt by a symmetry of Heisenberg type and is also considered as a perturbation of the Markov operator T0=T. We prove that these operators have an isolated dominant eigenvalue which has an asymptotic expansion involving fractional powers of t. The parameters of this expansion have simple expressions in terms of tails and moments of the stationary measures of P and T.
Excitation of an upper hybrid wave by a high power laser beam in plasma
Authors: Purohit G. , Chauhan P.K. , Sharma R.P.
Published: April 2008

In the present investigation, the excitation of an upper hybrid wave (UHW) in a hot collisionless magneto-plasma by a relativistic laser beam propagating perpendicular to the static magnetic field and having its electric vector polarized along the direction of the static magnetic field (ordinary mode) is presented. Due to nonuniform intensity distribution of pump laser, the background electron concentration is modified. The amplitude of the UHW, which depends on the background electron concentration, is thus nonlinearly coupled with the laser beam. The effect of nonlinear coupling between the pump laser and UHW is studied. The effect of the relativistic electron mass nonlinearity and the relativistic self-focusing of the pump laser on the excitation of the UHW have been incorporated. The dynamics of the excitation of the UHW in different power domains of the laser beam is accordingly modified. It has been seen that the effect of changing the strength of the static magnetic field on the nonlinear coupling and the dynamics of the excitation of the UHW is significant. The focusing behavior of the UHW may find its relevance in the heating of plasmas near the upper hybrid resonance.
Inhibition factor reduces fast ignition threshold for laser fusion using nonlinear force driven block acceleration
Authors: Ghoranneviss M. , Malekynia B. , Hora H. , Miley G.H. , He X.
Published: April 2008

Fast ignition for fusion energy by using petawatt-picosecond (PW-ps) laser pulses was modified due to an anomaly based on extremely clean suppression of prepulses. The resulting plasma blocks with space charge neutral ion current densities above 1011Amp/cm2may be used to ignite deuterium-tritium at densities at or little above solid state density. The difficulty is to produce extremely high energy flux densities of the blocks. Results are reported how the threshold can be reduced by a factor up to fife if the inhibition factor for thermal conductivity due to electric double layers is included in the hydrodynamic analysis.
Geochemistry of basalt from the North Gorda segment of the Gorda Ridge: Evolution toward ultraslow spreading ridge lavas due to decreasing magma supply
Authors: Davis A. S. , Clague D. A. , Cousens B. L. , Keaten R. , Paduan J. B.
Published: April 2008

High‐density, precisely located, dive and rock‐corer basalt samples from the 65‐km‐long North Gorda ridge segment reveal compositional diversity as great as for the entire Gorda Ridge. Lava compositions along the ridge axis show considerable major and minor element diversity (MgO 9.2–4.4%, K2O 0.04–0.36%) for lavas erupted in close proximity. Although they form a near‐continuum in the higher MgO range, the samples can be separated into two groups; one is typical N‐type mid‐ocean ridge basalt (MORB) (K2O/TiO2 < 0.09), and the other is a more enriched T‐MORB (K2O/TiO2 > 0.09). Incompatible elements also reflect this grouping with (Ce/Yb)N < 1 and Zr/Nb > 20 for N‐MORB and (Ce/Yb)N > 1 and Zr/Nb < 20 for T‐MORB. Samples collected from off‐axis, over a distance of 4 km up the eastern rift valley wall, are all light rare earth element (LREE)‐depleted N‐MORB with a narrower compositional range (MgO of glasses 7.7 ± 0.3%, Zr/Nb = 38–50; (Ce/Yb)N < 1), although isotopic ratios are comparable to those on‐axis. Lavas erupted in the past, before the present‐day deep axial valley formed on this part of the ridge, were more uniform N‐MORB, generated by larger degrees of melting when magma supply was greater. Basalts from the adjoining southern Juan de Fuca Ridge segment, with comparable spreading rate but distinctly different ridge morphology, are also all LREE‐depleted N‐MORB, but the narrow range of evolved compositions of the sheet flows covering the broad, U‐shaped valley suggests shallower, more steady state magma reservoirs underlying this ridge segment. Basalts from Escanaba, the slowest spreading segment of Gorda Ridge, include N‐, T‐, and E‐MORB that were erupted from isolated volcanic centers. The pattern of incompatible element enrichment, especially in LREE, K, Ba, and 87Sr/86Sr, with decreasing spreading rate and magma supply is even more pronounced at the ultraslow spreading Arctic ridges where most lavas are E‐MORB (Zr/Nb < 10, (Ce/Yb)N >1.0–3.0). Arctic E‐MORB compositions lie along a common mixing trend with those from North Gorda. As the magma budget and/or partial melting decreases, a similar enriched component, especially in K, Ba, and LREE, widely present in the oceanic mantle is apparently incorporated to a greater degree. At North Gorda, morphology and chemical characteristics appear to evolve with time toward that of ultraslow spreading ridges.
Weakening of the subduction interface and its effects on surface heat flow, slab dehydration, and mantle wedge serpentinization
Authors: Wada Ikuko , Wang Kelin , He Jiangheng , Hyndman Roy D.
Published: April 2008

The shallow part of the interface between the subducting slab and the overriding mantle wedge is evidently weakened by the presence of hydrous minerals and high fluid pressure. We use a two‐dimensional finite element model, with a thin layer of uniform viscosity along the slab surface to represent the strength of the interface and a dislocation‐creep rheology for the mantle wedge, to investigate the effect of this interface “decoupling.” Decoupling occurs when the temperature‐dependent viscous strength of the mantle wedge is greater than that of the interface layer. We find that the maximum depth of decoupling is the key to most primary thermal and petrological processes in subduction zone forearcs. The forearc mantle wedge above a weakened subduction interface always becomes stagnant (<0.2% slab velocity), providing a stable thermal environment for the formation of serpentinite. The degree of mantle wedge serpentinization depends on the availability of aqueous fluids from slab dehydration. A very young and warm slab releases most of its bound H2O in the forearc, leading to a high degree of mantle wedge serpentinization. A very old and cold slab retains most of its H2O until farther landward, leading to a lower degree of serpentinization. Our preferred model for northern Cascadia has a maximum decoupling depth of about 70–80 km, which provides a good fit to surface heat flow data, predicts conditions for a high degree of serpentinization of the forearc mantle wedge, and is consistent with the observed shallow intraslab seismicity and low volume of arc volcanism.
A wind tunnel examination of shear stress partitioning for an assortment of surface roughness distributions
Authors: Brown S. , Nickling W. G. , Gillies J. A.
Published: April 2008

Surface roughness aids to ameliorate wind erosion by extracting a portion of the wind's momentum thereby reducing the quantity of stress on the surface. This paper evaluates the effect of different spatial arrangements of surface roughness on the partition of average drag forces and distribution of stress at the surface. A new tiered force balance was used in a wind tunnel to independently and simultaneously measure the drag on arrays of roughness elements and the drag on the intervening surface. In addition, Irwin sensors recorded point measurements of surface shear stress within the arrays. Roughness arrays consisted of small cylinders in four different spatial arrangements, one being staggered and three being simplifications of natural roughness configurations, at four roughness densities. Results from the tiered force balance and Irwin sensors indicate that the roughness configuration has a small impact on the average (R) and maximum (R″) drag partition. The protection of the surface increased with roughness density regardless of the roughness arrangement. Point measurements of shear stress revealed that the roughness configuration had a small impact on the distribution of shear stress at the surface, and that the maximum shear stress scaled to the average shear stress. Drag partition measurements were compared to the ratios predicted by the Raupach et al. (1993) model and a good degree of agreement was found for all configurations when using measured values of the β and m parameter.
CH4 and N2O emissions from a forest‐alas ecosystem in the permafrost taiga forest region, eastern Siberia, Russia
Authors: Takakai Fumiaki , Desyatkin Alexey R. , Lopez C. M. Larry , Fedorov Alexander N. , Desyatkin Roman V. , Hatano Ryusuke
Published: April 2008

‘Alases’ are mature thermokarst depressions covered by grassland distributed in taiga forests in central Yakutia, eastern Siberia, following thermokarst formation initiated in early Holocene. Alases are important land‐cover class in the central Yakutia lowland occupying 17% of the total land area. CH4 and N2O fluxes were measured temporally in a typical alas which have a pond at the center during the growing season of two years. Seven monitoring plots represented various vegetation types: a larch forest (F), a dry grassland (DG), four wet grasslands (WG) flooded temporarily or continuously, and a pond surface (P) flooded continuously without vegetation. The pond flooding area reached its maximum just after snow‐melting and decreased during the summer. The F and DG plots were small CH4 sinks. The wet plots (including WG and P) were large CH4 sources (cumulative value of growing season: 17 to 864 kg CH4‐C ha−1), and emission rates vary drastically depending on flooding conditions. All plots were slight sources or sinks of N2O except for the WG plots (0.16 to 1.7 kg N2O‐N ha−1) where peak emissions were observed after the flooding ended. The global warming potentials (time horizon of 100 years) of the cumulative N2O emissions from the plots were lower than those of each CH4 emissions. Estimated total CH4 emission from the whole WG area (7.93 ha) accounted for 88% of the emission from the whole alas (28.9 ha). The current permafrost‐taiga region in central Yakutia could be a net CH4 source owing to the presence of alases.
An Enigmatic Carbonate Layer in Everglades Tree Island Peats
Authors: Graf Maria‐Theresia , Schwadron Margo , Stone Peter A. , Ross Michael , Chmura Gail L.
Published: April 2008

Recent archaeological excavations on the heads (i.e., the most elevated and upstream parts) of several large Everglades fixed tree islands may reshape what is understood about the age and formation of these landforms, and about the role of humans in the early Everglades wetland, between 3500 and 1000 B.C. Tree islands are patches of high ground, dry enough to support trees, that rise about 1 meter above the surrounding wetland, and those islands termed “fixed” are the large teardrop‐shaped islands thought to have formed over localized high points in the underlying bedrock (Figures 1a and 1b). A hard, cemented carbonate layer perched in the sediments of two tree islands in the southern Everglades was discovered by U.S. National Park Service archaeologists, and penetration of it with a concrete saw revealed that beneath the layer are unconsolidated sediments containing archaeological artifacts dating back to late‐Archaic times (3000–1000 B.C.) [Schwadron, 2006].
Updated 2008 Surface Snowmelt Trends in Antarctica
Authors: Tedesco Marco
Published: April 2008

Surface snowmelt in Antarctica in 2008, as derived from spaceborne passive microwave observations at 19.35 gigahertz, was 40% below the average of the period 1987–2007. The melting index (MI, a measure of where melting occurred and for how long) in 2008 was the second‐smallest value in the 1987–2008 period, with 3,465,625 square kilometers times days (km2 x days) against the average value of 8,407,531 km2 x days (Figure 1a). Melt extent (ME, the extent of the area subject to melting) in 2008 set a new minimum with 297,500 square kilometers, against an average value of approximately 861,812 square kilometers. The 2008 updated melting index and melt extent trends over the whole continent, as derived from a linear regression approach, are −164,487 km2 x days per year (MI) and −11,506 square kilometers per year (ME), respectively.
Outstanding Student Paper Awards
Authors: Anonymous
Published: April 2008

Aihua Zhu, University of California, San Diego, La Jolla, Spectral signature of radiative forcing by East Asian dust‐soot mixture.

Ashton Robinson Cook, NOAA Storm Prediction Center and University of Oklahoma, Norman, The relation of El Niño Southern Oscillation (ENSO) to winter tornado outbreaks.
Lagrangian simulation of multidimensional anomalous transport at the MADE site
Authors: Zhang Yong , Benson David A.
Published: April 2008

Contaminant transport through regional‐scale natural geological formations typically exhibits several “anomalous” features, including direction‐dependent spreading rates, channeling along preferential flow paths, trapping of solute in relatively immobile domains, and/or the local variation of transport speed. Simulating these plume characteristics can be computationally intensive using a traditional advection‐dispersion equation (ADE) because anomalous features of transport generally depend on local‐scale subsurface properties. Here we develop an alternative simulation approach that solves the full nonlocal, multidimensional, spatiotemporal fractional‐order ADE with variable coefficients in a Lagrangian framework using a novel non‐Markovian random walk method. This model allows us to simulate anomalous plumes without the need to explicitly define local‐scale heterogeneity. The simple model accurately simulates the tritium plume measured at the extensively characterized MADE test site.
ENA periodicities at Saturn
Authors: Carbary J. F. , Mitchell D. G. , Brandt P. , Paranicas C. , Krimigis S. M.
Published: April 2008

The Magnetospheric Imaging Instrument (MIMI) on the Cassini spacecraft has observed energetic neutral atoms (ENA) at Saturn for three years from 2004 to 2007. The 20–50 keV hydrogen and 64–144 keV oxygen neutrals were examined for periodic behavior by projecting their images onto a plane perpendicular to Saturn's equatorial plane and summing the emissions along the vertical. The resulting “strip” images were then subjected to a Lomb periodogram analyses for the period between mid‐2004 to mid‐2007. The hydrogens display erratic periods in the 8–13 hour range, while the oxygens exhibit a very strong, repeatable period of 10.8 ± 0.2 hours, which is close to the nominal period of Saturn kilometric radiation as well as the period of energetic particles in Saturn's outer magnetosphere.
Marine aerosol chemistry gradients: Elucidating primary and secondary processes and fluxes
Authors: Ceburnis Darius , O'Dowd Colin D. , Jennings Gerard S. , Facchini Maria Cristina , Emblico Lorenza , Decesari Stefano , Fuzzi Sandro , Sakalys Jonas
Published: April 2008

Production mechanisms of aerosol chemical species, in terms of primary and secondary processes, were studied using vertical concentration gradient measurements at the coastal research station in Mace Head, Ireland. Total gravimetric PM1.0 mass, sea salt and water insoluble organic carbon (WIOC) concentration profiles showed a net production at the surface (i.e. primary production), while nssSO4 and water soluble organic carbon (WSOC) concentration profiles showed a net removal at the surface. These observations indicate that WSOC was predominantly of secondary origin and that WIOC was predominantly of primary origin. Derived PM1 mass fluxes compared reasonably well with those previously obtained from an eddy covariance (EC) technique following a power law relationship with the wind speed (FPM1 = 0.000096*U4.23). For cases with clear primary organic mass fluxes in the flux footprint WIOM mass fluxes ranged between 0.16 and 1.02 ng m−2 s−1 and WIOM/sea salt mass ratio was 0.34–3.6, in good agreement with previous measurements at Mace Head.
ChIPping away at gene regulation
Authors: Massie Charles E , Mills Ian G
Published: April 2008

The coordinated regulation of gene expression in higher eukaryotes is complex and poorly understood. Recent technological advances have allowed the first insights into these networks on a genome‐wide scale. These investigations have identified transcription factor target sites in the genome and successfully predicted cooperative interactions with other factors. However, a detailed understanding of the processes that coordinate gene expression remains elusive. Here, we highlight the advances that have been made using current methods, and the need for new technologies to address the gaps in our knowledge and to map these complex pathways further.
Determination of T‐cell fate by dendritic cells
Authors: Diebold Sandra S
Published: April 2008

Dendritic cells (DC) are professional antigen‐presenting cells with a unique T‐cell stimulatory aptitude that play a crucial role in the instruction of adaptive immune responses upon infection. By controlling the initiation of a diverse set of effector functions, which are suitable for the elimination of a wide range of pathogens, DCs form the pivotal link between the innate and the adaptive immune system. The innate pattern recognition pathways that trigger DC activation are central for skewing of the adaptive immune responses that are subsequently induced. Thus innate activation not only precedes adaptive immune activation, it also controls it and tailors the effector functions to the requirements of the infection. The adaptive immune response has to match the nature of the infection, but this does not only concern the type of pathogen, it is also affected by the localization of the infection. Tissue homeostasis has to be ensured and thus tissue‐derived environmental factors influence the functional activity of activated DCs and thereby contribute to shaping of the immune response. Adaptive immune responses are vital for the elimination of pathogens, have the potential to attack tumor cells and play a detrimental role during transplant rejection and in a variety of autoimmune diseases. Better understanding of the mechanisms that control the induction of different T‐cell effector functions will enable the development of strategies to manipulate the immune system in the context of vaccination, tumor immunotherapy, transplantation and autoimmunity.
The limits of human performance
Authors: Beneke Ralph , Böning Dieter
Published: April 2008

Human performance, defined by mechanical resistance and distance per time, includes human, task and environmental factors, all interrelated. It requires metabolic energy provided by anaerobic and aerobic metabolic energy sources. These sources have specific limitations in the capacity and rate to provide re-phosphorylation energy, which determines individual ratios of aerobic and anaerobic metabolic power and their sustainability. In healthy athletes, limits to provide and utilize metabolic energy are multifactorial, carefully matched and include a safety margin imposed in order to protect the integrity of the human organism under maximal effort. Perception of afferent input associated with effort leads to conscious or unconscious decisions to modulate or terminate performance; however, the underlying mechanisms of cerebral control are not fully understood. The idea to move borders of performance with the help of biochemicals is two millennia old. Biochemical findings resulted in highly effective substances widely used to increase performance in daily life, during preparation for sport events and during competition, but many of them must be considered as doping and therefore illegal. Supplements and food have ergogenic potential; however, numerous concepts are controversially discussed with respect to legality and particularly evidence in terms of usefulness and risks. The effect of evidence-based nutritional strategies on adaptations in terms of gene and protein expression that occur in skeletal muscle during and after exercise training sessions is widely unknown. Biochemical research is essential for better understanding of the basic mechanisms causing fatigue and the regulation of the dynamic adaptation to physical and mental training.
Theory of polyelectrolyte adsorption onto surfaces patterned with charge and topography
Authors: Hoda Nazish , Kumar Satish
Published: April 2008

Mean-field theory is used to derive criteria for the adsorption of a weakly charged polyelectrolyte molecule from salt solution onto surfaces patterned with charge and topography. For flat surfaces patterned with periodic arrays of charged patches, the adsorbed layer thickness predicted using mean-field theory and that found by Brownian dynamics simulations are in quantitative agreement in the strong-adsorption regime, which corresponds to sufficiently small κ or sufficiently large ∣σeffq∣, where κ is the inverse Debye screening length, σeff is an effective surface charge density, and q is the charge on each segment of the polyelectrolyte. Qualitative agreement is obtained in the weak-adsorption regime, and for the case where surfaces are patterned with both charge and topography. For uniformly charged, sinusoidally corrugated surfaces, the theory predicts that the critical temperature required for adsorption can be greater than or less than the corresponding value for a flat surface depending on the relative values of κ and the corrugation wave number. If the surface charge is also allowed to vary sinusoidally, then adsorption is predicted to occur only when the topography crests have a surface charge opposite to that of the polyelectrolyte. Surfaces patterned with rectangular indentations having charged bottoms which are separated by flat charged plateaus are investigated as well. Adsorption is predicted to occur even when the net surface charge is zero, provided that the plateaus have a charge opposite to that of the polyelectrolyte. If the charge on the plateaus and polyelectrolyte is the same, adsorption may still occur if electrostatic attraction from the indentation bottoms is sufficiently strong.
Stereographic projection path integral simulations of (HCl)n clusters (n=2–5): Evidence of quantum induced melting in small hydrogen bonded networks
Authors: Avilés Michael W. , McCandless Michelle L. , Curotto E.
Published: April 2008

We investigate the quantum thermodynamic properties of small (HCl)n clusters using stereographic projection path integral simulations. The HCl stretches are rigid, the orientations are mapped with stereographic projection coordinates, and we make use of the reweighted random series techniques to obtain cubic convergence with respect to the number of path coefficients. Path integral simulations are converged at and above 10K for the pentamer and above 15K for the dimer and the trimer. None of the systems display a melting feature in the classical limit. We find an evidence of quantum induced melting between 15 and 45K.
Stretching an anisotropic DNA
Authors: Eslami-Mossallam B. , Ejtehadi M. R.
Published: April 2008

We present a perturbation theory to find the response of an anisotropic DNA to the external tension. It is shown that the anisotropy has a nonzero but small contribution to the force-extension curve of the DNA. Thus an anisotropic DNA behaves like an isotropic one with an effective bending constant equal to the harmonic average of its soft and hard bending constants.
Energy transfer of highly vibrationally excited naphthalene. II. Vibrational energy dependence and isotope and mass effects
Authors: Liu Chen-Lin , Hsu Hsu Chen , Hsu Yuan Chin , Ni Chi-Kung
Published: April 2008

The vibrational energy dependence, H and D atom isotope effects, and the mass effects in the energy transfer between rare gas atoms and highly vibrationally excited naphthalene in the triplet state were investigated using crossed-beam/time-sliced velocity-map ion imaging at various translational collision energies. Increase of vibrational energy from 16194to18922cm−1 does not make a significant difference in energy transfer. The energy transfer properties also remain the same when H atoms in naphthalene are replaced by D atoms, indicating that the high vibrational frequency modes do not play important roles in energy transfer. They are not important in supercollisions either. However, as the Kr atoms are replaced by Xe atoms, the shapes of energy transfer probability density functions change. The probabilities for large translation to vibration/rotation energy transfer (T→VR) and large vibration to translation energy transfer (V→T) decrease. High energy tails in the backward scatterings disappear, and the probability for very large vibration to translation energy transfer such as supercollisions also decreases.
Rotational state selection of a CH3I+ ion beam using vacuum ultraviolet–mass-analyzed threshold ionization spectroscopy: Characterization using photodissociation spectroscopy
Authors: Bae Yong Jin , Kim Myung Soo
Published: April 2008

The ÃA12←X̃E3∕22 transition of CH3I+ was investigated by photodissociation (PD) of the cation generated by one-photon mass-analyzed threshold ionization (MATI). Compared to the PD spectrum obtained by excitation of the cation in the main 0-0 band in the MATI spectrum, those obtained by excitation of the cations in the satellite structures showed substantially simplified rotational structures for nondegenerate vibronic bands. Spectral simplification occurred because each satellite consisted mostly of cations with one K quantum number. Spectroscopic constants in the ground vibronic state and in the 2135, 2138, 39, and 313 nondegenerate vibrational states in ÃA12 were determined via spectral fitting. Also, those in the 213n61 (n=1?) degenerate state, which had been reported previously, was improved. The K quantum number in each satellite determined by the present high resolution study was compatible with the prediction by the symmetry selection rule for photoionization. That is, the K quantum number of the ion core in high Rydberg states accessed by one-photon excitation was found to be conserved upon pulsed field ionization. This work demonstrates generation of mass-selected, vibronically selected, and K-selected ion beam by one-photon MATI.
Aerodynamic loads on cactus-shaped cylinders at low Reynolds numbers
Authors: Babu Pradeep , Mahesh Krishnan
Published: April 2008

Direct numerical simulations of flow past cactus-shaped cylinders are performed at Reynolds numbers of 20, 100, and 300. The results are contrasted to those from smooth cylinders at the same Reynolds numbers. The cavities in the cactus-shaped cylinders are seen to reduce the forces acting on them. At Reynolds number of 20, the drag is reduced by 22% due to reduction in the viscous forces. At Reynolds number of 100, the unsteady pressure forces increase, while the unsteady viscous forces acting on the cactus-shaped cylinder decrease. The overall reduction in drag force is about 18%. At Reynolds number of 300, onset of three dimensionality is observed together with significant decrease in pressure and viscous forces. Both the mean and fluctuating forces are found to decrease considerably. The Strouhal number is also found to decrease by about 10%. These reductions in force magnitudes and observed wake instabilities are attributed to the presence of large-scale, quiescent, recirculating flow within the cactus cavities.
Energy landscapes of the monomer and dimer of the Alzheimer’s peptide Aβ(1–28)
Authors: Dong Xiao , Chen Wei , Mousseau Normand , Derreumaux Philippe
Published: April 2008

The cytoxicity of Alzheimer’s disease has been linked to the self-assembly of the 40∕42 amino acid of the amyloid-β (Aβ) peptide into oligomers. To understand the assembly process, it is important to characterize the very first steps of aggregation at an atomic level of detail. Here, we focus on the N-terminal fragment 1–28, known to form fibrils in vitro. Circular dichroism and NMR experiments indicate that the monomer of Aβ(1–28) is α-helical in a membranelike environment and random coil in aqueous solution. Using the activation-relaxation technique coupled with the OPEP coarse grained force field, we determine the structures of the monomer and of the dimer of Aβ(1–28). In agreement with experiments, we find that the monomer is predominantly random coil in character, but displays a non-negligible β-strand probability in the N-terminal region. Dimerization impacts the structure of each chain and leads to an ensemble of intertwined conformations with little β-strand content in the region Leu17-Ala21. All these structural characteristics are inconsistent with the amyloid fibril structure and indicate that the dimer has to undergo significant rearrangement en route to fibril formation.
Photochemical stability of nonlinear optical chromophores in polymeric and crystalline materials
Authors: Rezzonico Daniele , Kwon Seong-Ji , Figi Harry , Kwon O-Pil , Jazbinsek Mojca , Günter Peter
Published: April 2008

We compare the photochemical stability of the nonlinear optical chromophore configurationally locked polyene 2-{3-[2-(4-dimethylaminophenyl)vinyl]-5,5-dimethylcyclohex-2-enylidene} malononitrile (DAT2) embedded in a polymeric matrix and in a single-crystalline configuration. The results show that, under resonant light excitations, the polymeric compound degrades through an indirect process, while the DAT2 crystal follows a slow direct process. We show that chromophores in a crystalline environment exhibit three orders of magnitude better photostability as compared to guest-host polymer composites.
Shock, release and Taylor impact of the semicrystalline thermoplastic polytetrafluoroethylene
Authors: Bourne N. K. , Brown E. N. , Millett J. C. F. , Gray G. T.
Published: April 2008

The high strain-rate response of polymers is a subject that has gathered interest over recent years due to their increasing engineering importance, particularly in load bearing applications subject to extremes of pressure and strain rate. The current work presents two specific sets of experiments interrogating the effect of dynamic, high-pressure loading in the regime of the phase II to phase III pressure-induced crystalline phase transition in polytetrafluoroethylene (PTFE). These are gas-gun driven plate- and Taylor impact. Together these experiments highlight several effects associated with the dynamic, pressure-induced phase transitions in PTFE. An elevated release wave speed shows evidence of a pressure-induced phase change at a stress commensurate with that observed statically. It is shown that convergence between analytic derivations of release wave speed and the data requires the phase II to III transition to occur. Taylor impact is an integrated test that highlights continuum behavior that has origin in mesoscale response. There is a rapid transition from ductile to brittle behavior observed that occurs at a pressure consistent with this phase transition.