bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of aridity and rainfall seasonality on vegetation in the southern tropics of East Africa during the Pleistocene/Holocene transition
Authors: Ivory Sarah J. , Lézine Anne-Marie , Vincens Annie , Cohen Andrew S.
Published: December 2011

Fossil pollen analyses from northern Lake Malawi, southeast Africa, provide a high-resolution record of vegetation change during the Pleistocene/Holocene transition (~ 18–9 ka). Recent studies of local vegetation from lowland sites have reported contrasting rainfall signals during the Younger Dryas (YD). The Lake Malawi record tracks regional vegetation changes and allows comparison with other tropical African records identifying vegetation opening and local forest maintenance during the YD. Our record shows a gradual decline of afromontane vegetation at 18 ka. Around 14.5 ka, tropical seasonal forest and Zambezian miombo woodland became established. At ~ 13 ka, drier, more open formations gradually became prevalent. Although tropical seasonal forest taxa were still present in the watershed during the YD, this drought-intolerant forest type was likely restricted to areas of favorable edaphic conditions along permanent waterways. The establishment of drought-tolerant vegetation followed the reinforcement of southeasterly tradewinds resulting in a more pronounced dry winter season after ~ 11.8 ka. The onset of the driest, most open vegetation type was coincident with a lake low stand at the beginning of the Holocene. This study demonstrates the importance of global climate forcing and local geomorphological conditions in controlling vegetation distribution.
Iron requirements based upon iron absorption tests are poorly predicted by haematological indices in patients with inactive inflammatory bowel disease
Authors: Lomer Miranda C. E. , Cook William B. , Jan-Mohamed Hamid Jan B. , Hutchinson Carol , Liu Ding Yong , Hider Robert C. , Powell Jonathan J.
Published: December 2011

Fe deficiency and Fe-deficiency anaemia are common in patients with inflammatory bowel disease (IBD). Traditional clinical markers of Fe status can be skewed in the presence of inflammation, meaning that a patient's Fe status can be misinterpreted. Additionally, Fe absorption is known to be down-regulated in patients with active IBD. However, whether this is the case for quiescent or mildly active disease has not been formally assessed. The present study aimed to investigate the relationship between Fe absorption, Fe requirements and standard haematological indices in IBD patients without active disease. A group of twenty-nine patients with quiescent or mildly active IBD and twenty-eight control subjects undertook an Fe absorption test that measured sequential rises in serum Fe over 4 h following ingestion of 200 mg ferrous sulphate. At baseline, serum Fe, transferrin saturation, non-transferrin-bound Fe (NTBI), ferritin and soluble transferrin receptor were all measured. Thereafter (30–240 min), only serum Fe and NTBI were measured. Fe absorption did not differ between the two groups (P = 0·9; repeated-measures ANOVA). In control subjects, baseline haematological parameters predicted Fe absorption (i.e. Fe requirements), but this was not the case for patients with IBD. Fe absorption is normal in quiescent or mildly active IBD patients but standard haematological parameters do not accurately predict Fe requirements.
NOTE ON q-DEDEKIND-TYPE SUMS RELATED TO q-EULER POLYNOMIALS
Authors: KIM TAEKYUN
Published: December 2011

Recently, q-Dedekind-type sums related to q-zeta function and basic L-series are studied by Simsek in [13] (Y. Simsek, q-Dedekind type sums related to q-zeta function and basic L-series, J. Math. Anal. Appl. 318 (2006), 333–351) and Dedekind-type sums related to Euler numbers and polynomials are introduced in the previous paper [11] (T. Kim, Note on Dedekind type DC sums, Adv. Stud. Contem. Math. 18 (2009), 249–260). It is the purpose of this paper to construct a p-adic continuous function for an odd prime to contain a p-adic q-analogue of the higher order Dedekind the type sums related to q-Euler polynomials and numbers by using an invariant p-adic q-integrals.
THE DIVISIBILITY OF THE CLASS NUMBER OF THE IMAGINARY QUADRATIC FIELD
Authors: MINHUI ZHU , TINGTING WANG
Published: December 2011

Let hK denote the class number of the imaginary quadratic field $K=\mathbf{Q}(\sqrt{2^{2m}-k^n})$, where m and n are positive integers, k is an odd integer with k > 1 and 22m < kn. In this paper we prove that if either 3 ∣ n and 22m − kn ≡ 5(mod 8) or n = 3 and k = (22m+2 −1)/3, then ∣ hK. Otherwise, we have n ∣ hK.
A MEAN VALUE RELATED TO D. H. LEHMER'S PROBLEM AND THE RAMANUJAN'S SUM
Authors: WENPENG ZHANG
Published: December 2011

Let q > 1 be an odd integer and c be a fixed integer with (c, q) = 1. For each integer a with 1 ≤ a ≤ q − 1, it is clear that there exists one and only one b with 0 ≤ b ≤ q − 1 such that ab ≡ c (mod q). Let N(c, q) denotes the number of all solutions of the congruence equation ab ≡ c (mod q) for 1 ≤ a, b ≤ q − 1 in which a and b are of opposite parity, where b is defined by the congruence equation bb ≡ 1(modq). The main purpose of this paper is using the mean value theorem of Dirichlet L-functions to study the mean value properties of a summation involving (N(c, q) − φ(q)) and Ramanujan's sum, and give two exact computational formulae.
STABILITY OF GORENSTEIN FLAT MODULES
Authors: BOUCHIBA SAMIR , KHALOUI MOSTAFA
Published: December 2011

Sather-Wagstaff et al. proved in [8] (S. Sather-Wagsta, T. Sharif and D. White, Stability of Gorenstein categories, J. Lond. Math. Soc.(2), 77(2) (2008), 481–502) that iterating the process used to define Gorenstein projective modules exactly leads to the Gorenstein projective modules. Also, they established in [9] (S. Sather-Wagsta, T. Sharif and D. White, AB-contexts and stability for Goren-stein at modules with respect to semi-dualizing modules, Algebra Represent. Theory14(3) (2011), 403–428) a stability of the subcategory of Gorenstein flat modules under a procedure to build R-modules from complete resolutions. In this paper we are concerned with another kind of stability of the class of Gorenstein flat modules via-à-vis the very Gorenstein process used to define Gorenstein flat modules. We settle in affirmative the following natural question in the setting of a left GF-closed ring R: Given an exact sequence of Gorenstein flat R-modules G = ⋅⋅⋅ G2G1G0G−1G−2 ⋅⋅⋅ such that the complex H ⊗RG is exact for each Gorenstein injective right R-module H, is the module M:= Im(G0 → G−1) a Gorenstein flat module?
STABILITY OF GORENSTEIN FLAT CATEGORIES
Authors: YANG GANG , LIU ZHONGKUI
Published: December 2011

A left R-module M is called two-degree Gorenstein flat if there exists an exact sequence of Gorenstein flat left R-modules ⋅⋅⋅ → G2 → G1 → G0 → G−1 → G−2 → ⋅⋅⋅ such that M ≅ Ker(G0 → G−1) and it remains exact after applying H ⊗R- for any Gorenstein injective right R-module H. In this paper we first give some characterisations of Gorenstein flat objects in the category of complexes of modules and then use them to show that two notions of the two-degree Gorenstein flat and the Gorenstein flat left R-modules coincide when R is right coherent.
THE COMPLEXITY OF THE EQUIVALENCE PROBLEM OVER FINITE RINGS
Authors: HORVÁTH GÁBOR
Published: December 2011

We investigate the complexity of the equivalence problem over a finite ring when the input polynomials are written as sum of monomials. We prove that for a finite ring if the factor by the Jacobson radical can be lifted in the centre, then this problem can be solved in polynomial time. This result provides a step in proving a dichotomy conjecture of Lawrence and Willard (J. Lawrence and R. Willard, The complexity of solving polynomial equations over finite rings (manuscript, 1997)).
INTEGRAL FORMULAE ON QUASI-EINSTEIN MANIFOLDS AND APPLICATIONS
Authors: BARROS A. , RIBEIRO E.
Published: December 2011

The aim of this paper is to extend for the m-quasi-Einstein metrics some integral formulae obtained in [1] (C. Aquino, A. Barros and E. Ribeiro Jr., Some applications of the Hodge-de Rham decomposition to Ricci solitons, Results Math. 60 (2011), 245–254) for Ricci solitons and derive similar results achieved there. Moreover, we shall extend the m-Bakry-Emery Ricci tensor for a vector field X on a Riemannian manifold instead of a gradient field ∇f, in order to obtain some results concerning these manifolds that generalize their correspondents to a gradient field.
Magnetic resonance imaging for Ménière's disease: correlation with tone burst electrocochleography
Authors: Hornibrook J , Coates M , Goh A , Gourley J , Bird P
Published: December 2011

The newly developed use of magnetic resonance imaging of the human inner ear, on a 3 Tesla scanner with intratympanically administered gadolinium, can now reliably distinguish perilymph from endolymph and visually confirm the presence or absence of endolymphatic hydrops. Transtympanic tone burst electrocochleography is an established, and under-utilised evoked response electrophysiological test for hydrops, but it relies on a symptom score to indicate the likelihood of hydrops being present. The current diagnostic criteria for Ménière's disease make no allowance for any in vivo test, making diagnostic errors likely. In this small pilot study of three patients undergoing tone burst electrocochleography, subsequent magnetic resonance imaging confirmed or excluded the hydrops that the electrocochleography predicted. Magnetic resonance imaging of the inner ear is a safe technique that can be performed in conjunction with imaging of the VIIIth cranial nerves. As this report comprised only three patients in a pilot study, rigorous clinical studies are required to define the possible role of magnetic resonance imaging in the diagnosis of Ménière's disease.
Molecular signatures of peripheral blood mononuclear cells during chronic interferon-α treatment: relationship with depression and fatigue
Authors: Felger J. C. , Cole S. W. , Pace T. W. W. , Hu F. , Woolwine B. J. , Doho G. H. , Raison C. L. , Miller A. H.
Published: December 2011

Background

Interferon-alpha (IFN-α) treatment for infectious disease and cancer causes high rates of depression and fatigue, and has been used to investigate the impact of inflammatory cytokines on brain and behavior. However, little is known about the transcriptional impact of chronic IFN-α on immune cellsin vivoand its relationship to IFN-α-induced behavioral changes.

Method

Genome-wide transcriptional profiling was performed on peripheral blood mononuclear cells (PBMCs) from 21 patients with chronic hepatitis C virus (HCV) either awaiting IFN-α therapy (n=10) or at 12 weeks of IFN-α treatment (n=11).

Results

Significance analysis of microarray data identified 252 up-regulated and 116 down-regulated gene transcripts. Of the up-regulated genes, 2′-5′-oligoadenylate synthetase 2 (OAS2), a gene linked to chronic fatigue syndrome (CFS), was the only gene that was differentially expressed in patients with IFN-α-induced depression/fatigue, and correlated with depression and fatigue scores at 12 weeks (r=0.80,p=0.003 andr=0.70,p=0.017 respectively). Promoter-based bioinformatic analyses linked IFN-α-related transcriptional alterations to transcription factors involved in myeloid differentiation, IFN-α signaling, activator protein-1 (AP1) and cAMP responsive element binding protein/activation transcription factor (CREB/ATF) pathways, which were derived primarily from monocytes and plasmacytoid dendritic cells. IFN-α-treated patients with high depression/fatigue scores demonstrated up-regulation of genes bearing promoter motifs for transcription factors involved in myeloid differentiation, IFN-α and AP1 signaling, and reduced prevalence of motifs for CREB/ATF, which has been implicated in major depression.

Conclusions

Depression and fatigue during chronic IFN-α administration were associated with alterations in the expression (OAS2) and transcriptional control (CREB/ATF) of genes linked to behavioral disorders including CFS and major depression, further supporting an immune contribution to these diseases.
Rabbinic Authority, Medical Rhetoric, and Body Hermeneutics in Mishnah Nega‘im
Authors: Balberg Mira
Published: December 2011

The second century CE has long been recognized as a time of intense preoccupation with medicine and health in the Graeco-Roman world. Medicine had always been a part of the Greekpaideia, and acquaintance with it was traditionally required of every aristocrat, but it was during the second Sophistic period that a new form of medical self-presentation emerged in which the knowledge of medicine was hailed not only as one of the apices of the intellectualhabitus, but also as indispensable to everyday life. As Michel Foucault observed, the literature of this period placed an enormous emphasis on the body not just as a tool to be used but also as an end in itself, and the classic philosophical ideal of “caring for the Self” (epimeleia heautou) came to entail unrelenting attention to one's health and physical well-being. In this setting, the doctor—the bearer of medical knowledge and the ultimate caretaker of the Self—was seen as offering more than physical relief: The doctor was both a healer and a mentor, and functioned as a watchperson and a guide to right living. Indeed, it is in this period that we first come across the appellationsiatrophilosophos(doctor-philosopher) andiatrosophistes(doctor-sophist). Medical knowledge had thus become a most esteemed form of knowledge during the Antonine period of the Roman Empire, and doctors, as its guardians, interpreters, and practitioners, were invested with substantial power and authority.
From Boys to Men: Gender Politics and Jewish Identity in A Serious Man
Authors: Lang Ariella
Published: December 2011

Like many of their films, the Coen brothers' A Serious Man at once portrays a society dominated by men and calls into question what it is to be a man, especially but not exclusively a Jewish man. Indeed, while Larry Gopnik's wife is the source of much of his trouble, she, like her unmanageable daughter and the seductress-neighbor—the only women characters in the film—occupies minimal space in the narrative. But the role of the female, or the characteristics that differentiate men from women, occupy maximal space in the narrative: They are incorporated throughout the film in Gopnik's behaviors, in parodies of those behaviors, and in stereotypes of Jewish men, and non-Jewish men for that matter, that have a lengthy history in American television and film and in Western, Christian culture more generally. And so we find the central irony of A Serious Man, which is the presence of the female restricted to an indirect “male” presence that articulates the problem of male Jewish identity as it is construed and challenged in the context of American suburban life.
Refined carbohydrate intake in relation to non-verbal intelligence among Tehrani schoolchildren
Authors: Abargouei Amin Salehi , Kalantari Naser , Omidvar Nasrin , Rashidkhani Bahram , Rad Anahita Houshiar , Ebrahimi Azizeh Afkham , Khosravi-Boroujeni Hossein , Esmaillzadeh Ahmad
Published: December 2011

Objective

Nutrition has long been considered one of the most important environmental factors affecting human intelligence. Although carbohydrates are the most widely studied nutrient for their possible effects on cognition, limited data are available linking usual refined carbohydrate intake and intelligence. The present study was conducted to examine the relationship between long-term refined carbohydrate intake and non-verbal intelligence among schoolchildren.

Design

Cross-sectional study.

Setting

Tehran, Iran.

Subjects

In this cross-sectional study, 245 students aged 6–7 years were selected from 129 elementary schools in two western regions of Tehran. Anthropometric measurements were carried out. Non-verbal intelligence and refined carbohydrate consumption were determined using Raven's Standard Progressive Matrices test and a modified sixty-seven-item FFQ, respectively. Data about potential confounding variables were collected. Linear regression analysis was applied to examine the relationship between non-verbal intelligence scores and refined carbohydrate consumption.

Results

Individuals in top tertile of refined carbohydrate intake had lower mean non-verbal intelligence scores in the crude model (P < 0·038). This association remained significant after controlling for age, gender, birth date, birth order and breast-feeding pattern (P = 0·045). However, further adjustments for mother's age, mother's education, father's education, parental occupation and BMI made the association statistically non-significant. We found a significant inverse association between refined carbohydrate consumption and non-verbal intelligence scores in regression models (β = −11·359, P < 0·001). This relationship remained significant in multivariate analysis after controlling for potential confounders (β = −8·495, P = 0·038).

Conclusions

The study provides evidence indicating an inverse relationship between refined carbohydrate consumption and non-verbal intelligence among Tehrani children aged 6–7 years. Prospective studies are needed to confirm our findings.
Escherichia coliO157:H7 in beef cattle: on farm contamination and pre-slaughter control methods
Authors: Soon J. M. , Chadd S. A. , Baines R. N.
Published: December 2011

This paper addresses food safety in beef cattle production, with particular emphasis on factors that affect the prevalence ofEscherichia coliO157:H7 in beef cattle and on control methods that have been investigated. Product recalls and foodborne diseases due to this organism continue to occur even though control measures have been under investigation for over 20 years. Most meatborne outbreaks are due to improper food handling practices and consumption of undercooked meat. However, the majority of pathogenic bacteria that can spread at slaughter by cross-contamination can be traced back to the farm rather than originating from the slaughter plant. This would ideally require the adoption of rigorous on-farm intervention strategies to mitigate risks at the farm level. On-farm strategies to control and reduceE. coliO157:H7 at the farm level will reduce the risk of carcass contamination at slaughter and processing facilities although they will not eliminateE. coliO157:H7. The most successful strategy for reducing the risk of contamination of beef and beef products will involve the implementation of both pre- and post-harvest measures.
Detection of O antigens inEscherichia coli
Authors: DebRoy Chitrita , Roberts Elisabeth , Fratamico Pina M.
Published: December 2011

Lipopolysaccharide on the surface ofEscherichia coliconstitutes the O antigens which are important virulence factors that are targets of both the innate and adaptive immune systems and play a major role in host–pathogen interactions. O antigens are responsible for antigenic specificity of the strain and determine the O serogroup. The designation of O serogroups is important for classifyingE. colistrains, for epidemiological studies, in tracing the source of outbreaks of gastrointestinal or other illness, and for linking the source to the infection. For conventional serogroup identification, serotyping by agglutination reactions against antisera developed for each of the O serogroups has been used. In the last decade, many O-antigen gene clusters that encode for the enzymes responsible for the synthesis of the variable oligosaccharide region on the surface of the bacteria have been sequenced and characterized. Unique gene sequences within the O-antigen gene clusters have been targeted for identification and detection of many O groups using the polymerase chain reaction and microarrays. This review summarizes current knowledge on the DNA sequences of the O-antigen gene clusters, genetic-based methods for O-group determination and detection of pathogenicE. colibased on O-antigen and virulence gene detection, and provides perspectives on future developments in the field.
Persistency of pension contributions in the UK: evidence from the British Household Panel Survey
Authors: SMITH SARAH
Published: December 2011

This paper presents evidence from the British Household Panel Survey (BHPS) on the persistency of contributions to individual, private pensions. The BHPS contains a wealth of information on individuals' socio-economic and demographic characteristics, allowing detailed analysis of how individual circumstances – and changes in those circumstances – can affect whether or not someone continues to contribute. The paper finds variation in persistency rates by gender, earnings, and household income. As might be expected, changes in income and consumption needs (for example, becoming unemployed or the arrival of a new baby) increase the probability of lapse, but, conditional on these changes, the level of household income also matters, suggesting that pensions may be less affordable for those on low incomes, even in the absence of shocks.
Modeling transient groundwater flow by coupling ensemble Kalman filtering and upscaling
Authors: Li Liangping , Zhou Haiyan , Hendricks Franssen Harrie‐Jan , Gómez‐Hernández J. Jaime
Published: December 2011

The ensemble Kalman filter (EnKF) is coupled with upscaling to build an aquifer model at a coarser scale than the scale at which the conditioning data (conductivity and piezometric head) had been taken for the purpose of inverse modeling. Building an aquifer model at the support scale of observations is most often impractical since this would imply numerical models with many millions of cells. If, in addition, an uncertainty analysis is required involving some kind of Monte Carlo approach, the task becomes impossible. For this reason, a methodology has been developed that will use the conductivity data at the scale at which they were collected to build a model at a (much) coarser scale suitable for the inverse modeling of groundwater flow and mass transport. It proceeds as follows: (1) Generate an ensemble of realizations of conductivities conditioned to the conductivity data at the same scale at which conductivities were collected. (2) Upscale each realization onto a coarse discretization; on these coarse realizations, conductivities will become tensorial in nature with arbitrary orientations of their principal components. (3) Apply the EnKF to the ensemble of coarse conductivity upscaled realizations in order to condition the realizations to the measured piezometric head data. The proposed approach addresses the problem of how to deal with tensorial parameters, at a coarse scale, in ensemble Kalman filtering while maintaining the conditioning to the fine‐scale hydraulic conductivity measurements. We demonstrate our approach in the framework of a synthetic worth‐of‐data exercise, in which the relevance of conditioning to conductivities, piezometric heads, or both is analyzed.
Global‐mean precipitation and black carbon in AR4 simulations
Authors: Pendergrass A. G. , Hartmann D. L.
Published: December 2011

How much and why precipitation changes as the climate warms is uncertain, even for the global mean. In the 21st Century of the IPCC AR4 A1b forcing scenario, global‐mean precipitation increase per degree warming varies among models by over a factor of three. Clear‐sky atmospheric shortwave absorption change explains over half of the intermodel spread (r2= 0.61) in precipitation increase. Removing the part of clear‐sky atmospheric shortwave absorption change due to water vapor increase reveals that shortwave absorption forcing decreases in NCAR CCSM 3.0 but increases in GFDL CM 2.1, which we attribute to differences in black carbon forcing reported by these modeling groups. The range of applied forcing causes a range in atmospheric shortwave absorption increase, which leads to spread in precipitation increase. In contrast, in the CO2‐doubling forcing scenario, clear‐sky atmospheric shortwave absorption explains an insignificant amount of spread (r2 = 0.04).
Rheologic testing of wet kaolin reveals frictional and bi‐viscous behavior typical of crustal materials
Authors: Cooke Michele L. , van der Elst Nicholas J.
Published: December 2011

New rheological data for wet kaolin support its use in analog table‐top experiments that simulate deformation of the Earth's crust. Creep tests at small strain reveal that wet kaolin (62–66% water by mass) exhibits both elastic and viscous deformation characteristic of a Burger's material. When sheared to failure, the shear strength is relatively insensitive to the strain rate. The shear strength appears sensitive to the amount of initial compaction within the rheometer, which may indicate a normal‐stress dependency typical of frictional materials. Stepped velocity tests at large strain demonstrate velocity weakening rate and state frictional behavior after yielding. Because the wet kaolin exhibits deformation characteristic of both frictional materials and bi‐viscous materials, this material is well suited to simulate a variety of crustal deformational processes in scaled analog experiments.
Thin filament simulations for Earth's plasma sheet: Interchange oscillations
Authors: Wolf R. A. , Chen C. X. , Toffoletto F. R.
Published: December 2011

This paper presents a quantitative theory of “interchange oscillations,” which occur as an earthward‐moving low‐entropy plasma bubble slows and eventually comes to rest. Our theoretical picture is based on an idealized situation where an ideal‐MHD magnetic filament moves without friction through a stationary background that represents the plasma sheet. If the relevant region of the background plasma sheet is interchange stable, then the filament usually executes a damped oscillation about an equilibrium position, where its entropy parameter matches the local background. The oscillations are typically dramatic only if the equatorial plasma beta is greater than about one. We derive an approximate analytic formula for the oscillation period, which is not simply related to slow‐ or intermediate‐wave travel times. For an oscillation that Panov and collaborators carefully studied using THEMIS data, our simple theory, though based on an unrealistic 2D background magnetic field, predicted an oscillation period that agrees with the observations within about 40%. The simulations suggest that the ionospheric oscillation should lag behind the magnetospheric one by between 40 and 90 degrees. Ionospheric conductance affects the damping rate, which maximizes for an auroral zone conductance ∼2 S. Adding a friction force acting between the filament and the background increases the decay rate of the oscillation.
First principles investigations on the elasticity and phase stability of grossular garnet
Authors: Kawai Kenji , Tsuchiya Taku
Published: December 2011

In order to understand the fate of subducted continental materials by means of mechanisms such as tectonic erosion and sediment subduction, it is important to understand the high‐pressure stability and elastic properties of grossular garnet. We study these questions using the first principles computation method. Grossular garnet was found to dissociate into an assemblage of CaSiO3 Ca‐perovskite (Pv) and Al2O3 corundum (Cor) at about 23.4 GPa, accompanied by remarkable jumps of compressional wave (8.0%), shear wave (11.6%), bulk sound (5.7%) velocities, and density (12.1%). Although Pv with the grossular garnet composition was suggested experimentally after the decomposition reaction, this phase was found to be less stable than an assemblage of CaPv and Cor at pressures higher than 20 GPa. This indicates that observed Pv with the grossular garnet composition is metastable but can be obtained because of the slow kinetics of the garnet decomposition reaction. Our results imply that the dissociation of grossular garnet (as well as that of jadeite) included in continental materials subducted into the deep mantle increases the complexity of the 660 km discontinuity and can explain seismically observed multiple reflections. We have also investigated the anisotropy of elastic velocities of grossular garnet, CaPv, and Cor and found that CaPv is the most anisotropic mineral. This implies that CaPv could produce seismic anisotropy in the uppermost lower mantle.
Wet removal of black carbon in Asian outflow: Aerosol Radiative Forcing in East Asia (A‐FORCE) aircraft campaign
Authors: Oshima N. , Kondo Y. , Moteki N. , Takegawa N. , Koike M. , Kita K. , Matsui H. , Kajino M. , Nakamura H. , Jung J. S. , Kim Y. J.
Published: December 2011

The Aerosol Radiative Forcing in East Asia (A‐FORCE) aircraft campaign was conducted over East Asia in March–April 2009. During the A‐FORCE campaign, 120 vertical profiles of black carbon (BC) and carbon monoxide (CO) were obtained in the planetary boundary layer (PBL) and the free troposphere. This study examines the wet removal of BC in Asian outflow using the A‐FORCE data. The concentrations of BC and CO were greatly enhanced in air parcels sampled at 3–6 km in altitude over the Yellow Sea on 30 March 2009, associated with upward transport due to a cyclone with modest amounts of precipitation over northern China. In contrast, high CO concentrations without substantial enhancements of BC concentrations were observed in air parcels sampled at 5–6 km over the East China Sea on 23 April 2009, caused by uplifting due to cumulus convection with large amounts of precipitation over central China. The transport efficiency of BC (TEBC, namely the fraction of BC particles not removed during transport) in air parcels sampled above 2 km during the entire A‐FORCE period decreased primarily with the increase in the precipitation amount that air parcels experienced during vertical transport, although their correlation was modest (r2 = 0.43). TEBC also depended on the altitude to which air parcels were transported from the PBL and the latitude where they were uplifted locally over source regions. The median values of TEBC for air parcels originating from northern China (north of 33°N) and sampled at 2–4 km and 4–9 km levels were 86% and 49%, respectively, during the A‐FORCE period. These median values were systematically greater than the corresponding median values (69% and 32%, respectively) for air parcels originating from southern China (south of 33°N). Use of the A‐FORCE data set will contribute to the reduction of large uncertainties in wet removal process of BC in global‐ and regional‐scale models.
Productivity and sedimentary δ15N variability for the last 17,000 years along the northern Gulf of Alaska continental slope
Authors: Addison Jason A. , Finney Bruce P. , Dean Walter E. , Davies Maureen H. , Mix Alan C. , Stoner Joseph S. , Jaeger John M.
Published: December 2011

Biogenic opal, organic carbon, organic matter stable isotope, and trace metal data from a well‐dated, high‐resolution jumbo piston core (EW0408–85JC; 59° 33.3′N, 144° 9.21′W, 682 m water depth) recovered from the northern Gulf of Alaska continental slope reveal changes in productivity and nutrient utilization over the last 17,000 years. Maximum values of opal concentration (∼10%) occur during the deglacial Bølling‐Allerød (B‐A) interval and earliest Holocene (11.2 to 10.8 cal ka BP), moderate values (∼6%) occur during the Younger Dryas (13.0 to 11.2 cal ka BP) and Holocene, and minimum values (∼3.5%) occur during the Late Glacial Interval (LGI). When converted to opal mass accumulation rates, the highest values (∼5000 g cm−2 kyr−1) occur during the LGI prior to 16.7 cal ka BP, which points to a strong influence by LGI glacimarine sedimentation regimes. Similar patterns are also observed in total organic carbon and cadmium paleoproductivity proxies. Mid‐Holocene peaks in the terrestrial organic matter fraction at 5.5, 4.7, 3.5, and 1.2 cal ka BP indicate periods of enhanced delivery of glaciomarine sediments by the Alaska Coastal Current. The B‐A and earliest Holocene intervals are laminated, and enrichments of redox‐sensitive elements suggest dysoxic‐to‐anoxic conditions in the water column. The laminations are also associated with mildly enriched sedimentary δ15N ratios, indicating a link between productivity, nitrogen cycle dynamics, and sedimentary anoxia. After applying a correction for terrestrial δ15N contributions based on end‐member mixing models of terrestrial and marine organic matter, the resulting B‐A marine δ15N (6.3 ± 0.4 ‰) ratios are consistent with either mild denitrification, or increased nitrate utilization. These findings can be explained by increased micronutrient (Fe) availability during episodes of rapid rising sea level that released iron from the previously subaerial coastal plain; iron input from enhanced terrestrial runoff; and/or the intermittent presence of seasonal sea ice resulting from altered ocean/atmospheric circulation during the B‐A in the Gulf of Alaska.
Emerging roles of the FBW7 tumour suppressor in stem cell differentiation
Authors: Wang Zhiwei , Inuzuka Hiroyuki , Fukushima Hidefumi , Wan Lixin , Gao Daming , Shaik Shavali , Sarkar Fazlul H , Wei Wenyi
Published: December 2011

FBW7 is a ubiquitin E3 ligase substrate adaptor that targets many important oncoproteins—such as Notch, c‐Myc, cyclin E and c‐Jun—for ubiquitin‐dependent proteolysis. By doing so, it plays crucial roles in many cellular processes, including cell cycle progression, cell growth, cellular metabolism, differentiation and apoptosis. Loss of FBW7 has been observed in many types of human cancer, and its role as a tumour suppressor was confirmed by genetic ablation of FBW7 in mice, which leads to the induction of tumorigenesis. How FBW7 exerts its tumour suppression function, and whether loss of FBW7 leads to de‐differentiation or acquisition of stemness—a process frequently seen in human carcinomas—remains unclear. Emerging evidence shows that FBW7 controls stem cell self‐renewal, differentiation, survival and multipotency in various stem cells, including those of the haematopoietic and nervous systems, liver and intestine. Here, we focus on the function of FBW7 in stem cell differentiation, and its potential relevance to human disease and therapeutics.
DNA methylation: TET proteins—guardians of CpG islands?
Authors: Williams Kristine , Christensen Jesper , Helin Kristian
Published: December 2011

DNA methylation is involved in key cellular processes, including X‐chromosome inactivation, imprinting and transcriptional silencing of specific genes and repetitive elements. DNA methylation patterns are frequently perturbed in human diseases such as imprinting disorders and cancer. The recent discovery that the three members of the TET protein family can convert 5‐methylcytosine (5mC) into 5‐hydroxymethylcytosine (5hmC) has provided a potential mechanism leading to DNA demethylation. Moreover, the demonstration that TET2 is frequently mutated in haematopoietic tumours suggests that the TET proteins are important regulators of cellular identity. Here, we review the current knowledge regarding the function of the TET proteins, and discuss various mechanisms by which they contribute to transcriptional control. We propose that the TET proteins have an important role in regulating DNA methylation fidelity, and that their inactivation contributes to the DNA hypermethylation phenotype often observed in cancer.
Structural insights into the activation of RIG‐I, a nanosensor for viral RNAs
Authors: Jiang Qiu‐Xing , Chen Zhijian J
Published: December 2011

RIG‐I detects cytosolic viral dsRNA and initiates antiviral innate immune responses. Four recent reports of crystal structures that enlighten how RIG‐I is activated and recognizes RNA are discussed.
The present status of the nuclear shell model
Authors: Baranger Elizabeth Urey
Published: December 2011

The nuclear shell model is the central idea of nuclear structure. Theorists work either backwards from it (by this I mean they try to justify and derive its properties by stating a basic many-body Hamiltonian) or they work forward from it (they assume it is true and try to derive and justify the wide variety and complexity of nuclear properties including the well known phenomenon of nuclear collective motion). The shell model lurks somewhere in every paper on nuclear structure. The intense interest in the shell model among experimentalists for the last fifteen years has been due to the kinds of experiments that became possible during this time. It has been an era of direct reactions that characteristically excite simple degrees of freedom of the nucleus—just those most easily explained by the shell model. Without the possibility of these experiments and their analysis, the shell model might have been left mainly to the theorists, and they would have found it a very dry subject, without the wealth of experimental data they now have.
Collective microdynamics and noise suppression in dispersive electron beam transport
Authors: Gover Avraham , Dyunin Egor , Duchovni Tamir , Nause Ariel
Published: December 2011

A general formulation is presented for deep collective interaction micro-dynamics in dispersive e-beam transport. In the regime of transversely coherent interaction, the formulation is applicable to both coherent and random temporal modulation of the electron beam. We demonstrate its use for determining the conditions for suppressing beam current noise below the classical shot-noise level by means of transport through a dispersive section with a small momentum compaction parameter.
Investigation of tearing instability using GeFi particle simulation model
Authors: Wang X. Y. , Lin Y. , Chen L. , Lu X. , Kong W.
Published: December 2011

The gyrokinetic (GK) electron and fully kinetic ion (GeFi) simulation model of Lin et al. [Plasmas Phys. Controlled Fusion 53, 054013 (2011)] has been thoroughly benchmarked and validated for a two-dimensional (2D) Harris current sheet with a finite guide field. First, a gyrokinetic eigenmode theory for the collisionless tearing mode in the small Larmor radius limit is presented. The linear eigenmode structure and growth rate of the tearing mode obtained from the GeFi simulation are benchmarked against those from the GK eigenmode analysis in the limit of L≫ρi>ρe, where L is the current sheet half-width, ρi is ion Larmor radius, and ρe is electron Larmor radius. Second, to valid the GeFi model, both the linear and nonlinear tearing instabilities obtained from the GeFi simulations are compared with the Darwin particle-in-cell (PIC) simulation. The validation of the GeFi model for laboratory and space plasmas is also discussed. Meanwhile, the GeFi simulation is carried out to investigate both the linear and nonlinear tearing instabilities for cases with a broad range of L and guide magnetic field BG. It is found that in a wide current sheet with L > 4.5ρeK, the nonlinear saturation level of the island half-width is ws ≃ 3ρeK, where ρeK = ρeB0/Bx0, B0 is the strength of the asymptotic magnetic field, and Bx0 is the antiparallel field. On the other hand, in a thin current sheet with L < 2.5ρeK, ws ≃ 2.2 L. In addition, a high frequency electrostatic drift mode is found to coexist with the tearing mode.
Ab-initio multiplet calculation of oxygen vacancy effect on Ti-L2,3 electron energy loss near edge structures of BaTiO3
Authors: Ootsuki S. , Ikeno H. , Umeda Y. , Moriwake H. , Kuwabara A. , Kido O. , Ueda S. , Tanaka I. , Fujikawa Y. , Mizoguchi T.
Published: December 2011

The effect of oxygen vacancy on Ti-L2,3 electron energy-loss near-edge structures (ELNES) of BaTiO3 was theoretically investigated through ab initio multiplet calculation. The presence of an oxygen vacancy influences spectral features not only at the nearest neighbor Ti site but also at Ti sites further from the oxygen vacancy. The effects of different oxygen vacancy concentrations were also investigated. Based on this study, it was concluded that the detection limit for oxygen vacancy with Ti-L2,3 ELNES is approximately 1%.
Autonomous micro-magnet based systems for highly efficient magnetic separation
Authors: Zanini L. F. , Dempsey N. M. , Givord D. , Reyne G. , Dumas-Bouchiat F.
Published: December 2011

The various forces experienced by magnetic particles pumped through microfluidic channels placed above a chessboard array of micromagnets were calculated as a function of particle size and device dimensions. A device incorporating magnetically microstructured hard magnetic NdFeB films was fabricated. Good agreement was achieved between the calculated and observed distance over which magnetic particles travel before they are trapped. Using this simple and autonomous device, mixed solutions of magnetic and non-magnetic micro-particles were separated into two distinct solutions containing a concentration of up to 99.9% and 94.5% of non-magnetic and magnetic particles, respectively.
Copper doping of small gold cluster cations: Influence on geometric and electronic structure
Authors: Lang Sandra M. , Claes Pieterjan , Cuong Ngo Tuan , Nguyen Minh Tho , Lievens Peter , Janssens Ewald
Published: December 2011

The effect of Cu doping on the properties of small gold cluster cations is investigated in a joint experimental and theoretical study. Temperature-dependent Ar tagging of the clusters serves as a structural probe and indicates no significant alteration of the geometry of Aun+ (n = 1–16) upon Cu doping. Experimental cluster–argon bond dissociation energies are derived as a function of cluster size from equilibrium mass spectra and are in the 0.10–0.25 eV range. Near-UV and visible light photodissociation spectroscopy is employed in conjunction with time-dependent density functional theory calculations to study the electronic absorption spectra of Au4-mCum+ (m = 0, 1, 2) and their Ar complexes in the 2.00−3.30 eV range and to assign their fragmentation pathways. The tetramers Au4+, Au4+·Ar, Au3Cu+, and Au3Cu+·Ar exhibit distinct optical absorption features revealing a pronounced shift of electronic excitations to larger photon energies upon substitution of Au by Cu atoms. The calculated electronic excitation spectra and an analysis of the character of the optical transitions provide detailed insight into the composition-dependent evolution of the electronic structure of the clusters.
Nonlinear-optical brain anatomy by harmonic-generation and coherent Raman microscopy on a compact femtosecond laser platform
Authors: Doronina-Amitonova Lyubov V. , Lanin Aleksandr A. , Ivashkina Olga I. , Zots Marina A. , Fedotov Andrei B. , Anokhin Konstantin V. , Zheltikov Aleksei M.
Published: December 2011

An extended-cavity Cr:forsterite laser is integrated with a photonic-crystal fiber soliton frequency shifter and a periodically poled lithium niobate spectrum compressor for simultaneous harmonic-generation and coherent Raman brain imaging. Adapting the laser beam focusing geometry to the tissue morphology is shown to enable complementarity enhancement in tissue imaging by second- and third-harmonic generation, as well as coherent Raman scattering, facilitating quantitative image analysis.
High-resolution Fourier-transform infrared spectroscopy of the ν6 and Coriolis perturbation allowed ν10 modes of ketenimine
Authors: Bane Michael K. , Robertson Evan G. , Thompson Christopher D. , Appadoo Dominique R. T. , McNaughton Don
Published: December 2011

High-resolution FTIR spectra of the short lived species ketenimine have been recorded in the region 700–1300 cm−1 and over 1500 transitions of the ν10 and ν6 modes have been assigned. Effective rotational and centrifugal distortion parameters for the v10 = 1 and v6 = 1 (excluding Ka = 5) states were determined by co-fitting transitions, and treating strong a- and c-axis Coriolis interactions between them. Other perturbations attributed to interactions with the v8 = 2 and v12 = 1 + v8 = 1 dark-states were also observed and treated. The ν10 transitions are predicted to be inherently very weak, but are enhanced by an intensity stealing effect with the highly IR active ν6 mode. A mechanism for this intensity stealing in ketenimine is also detailed.
Atomistic theory of mesoscopic pattern formation induced by bimolecular surface reactions between oppositely charged molecules
Authors: Kuzovkov V. N. , Kotomin E. A. , Zvejnieks G.
Published: December 2011

The kinetics of mesoscopic pattern formation is studied for a reversible $A+B \rightleftharpoons 0$A+B⇌0 reaction between mobile oppositely charged molecules at the interface. Using formalism of the joint correlation functions, non-equilibrium charge screening and reverse Monte Carlo methods, it is shown that labyrinth-like percolation structure induced by (even moderate-rate) reaction is principally non-steady-state one and is associated with permanently growing segregation of dissimilar reactants and aggregation of similar reactants into mesoscopic size domains. A role of short-range and long-range reactant interactions in pattern formation is discussed.
Nonlinear viscous fluid patterns in a thin rotating spherical domain and applications
Authors: Ibragimov Ranis N.
Published: December 2011

We study the nonlinear incompressible fluid flows within a thin rotating spherical shell. The model uses the two-dimensional Navier-Stokes equations on a rotating three-dimensional spherical surface and serves as a simple mathematical descriptor of a general atmospheric circulation caused by the difference in temperature between the equator and the poles. Coriolis effects are generated by pseudoforces, which support the stable west-to-east flows providing the achievable meteorological flows rotating around the poles. This work addresses exact stationary and non-stationary solutions associated with the nonlinear Navier-Stokes. The exact solutions in terms of elementary functions for the associated Euler equations (zero viscosity) found in our earlier work are extended to the exact solutions of the Navier-Stokes equations (non-zero viscosity). The obtained solutions are expressed in terms of elementary functions, analyzed, and visualized.