bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimal Taylor–Couette turbulence
Authors: van Gils Dennis P. M. , Huisman Sander G. , Grossmann Siegfried , Sun Chao , Lohse Detlef 
Published: July 2012

AbstractStrongly turbulent Taylor–Couette flow with independently rotating inner and outer cylinders with a radius ratio of $\eta = 0. 716$ is experimentally studied. From global torque measurements, we analyse the dimensionless angular velocity flux ${\mathit{Nu}}_{\omega } (\mathit{Ta}, a)$ as a function of the Taylor number $\mathit{Ta}$ and the angular velocity ratio $a= \ensuremath{-} {\omega }_{o} / {\omega }_{i} $ in the large-Taylor-number regime $1{0}^{11} \lesssim \mathit{Ta}\lesssim 1{0}^{13} $ and well off the inviscid stability borders (Rayleigh lines) $a= \ensuremath{-} {\eta }^{2} $ for co-rotation and $a= \infty $ for counter-rotation. We analyse the data with the common power-law ansatz for the dimensionless angular velocity transport flux ${\mathit{Nu}}_{\omega } (\mathit{Ta}, a)= f(a)\hspace{0.167em} {\mathit{Ta}}^{\gamma } $, with an amplitude $f(a)$ and an exponent $\gamma $. The data are consistent with one effective exponent $\gamma = 0. 39\pm 0. 03$ for all $a$, but we discuss a possible $a$ dependence in the co- and weakly counter-rotating regimes. The amplitude of the angular velocity flux $f(a)\equiv {\mathit{Nu}}_{\omega } (\mathit{Ta}, a)/ {\mathit{Ta}}^{0. 39} $ is measured to be maximal at slight counter-rotation, namely at an angular velocity ratio of ${a}_{\mathit{opt}} = 0. 33\pm 0. 04$, i.e. along the line ${\omega }_{o} = \ensuremath{-} 0. 33{\omega }_{i} $. This value is theoretically interpreted as the result of a competition between the destabilizing inner cylinder rotation and the stabilizing but shear-enhancing outer cylinder counter-rotation. With the help of laser Doppler anemometry, we provide angular velocity profiles and in particular identify the radial position ${r}_{n} $ of the neutral line, defined by $ \mathop{ \langle \omega ({r}_{n} )\rangle } \nolimits _{t} = 0$ for fixed height $z$. For these large $\mathit{Ta}$ values, the ratio $a\approx 0. 40$, which is close to ${a}_{\mathit{opt}} = 0. 33$, is distinguished by a zero angular velocity gradient $\partial \omega / \partial r= 0$ in the bulk. While for moderate counter-rotation $\ensuremath{-} 0. 40{\omega }_{i} \lesssim {\omega }_{o} \lt 0$, the neutral line still remains close to the outer cylinder and the probability distribution function of the bulk angular velocity is observed to be monomodal. For stronger counter-rotation the neutral line is pushed inwards towards the inner cylinder; in this regime the probability distribution function of the bulk angular velocity becomes bimodal, reflecting intermittent bursts of turbulent structures beyond the neutral line into the outer flow domain, which otherwise is stabilized by the counter-rotating outer cylinder. Finally, a hypothesis is offered allowing a unifying view and consistent interpretation for all these various results.
Numerical study of magnetohydrodynamic duct flow at high Reynolds and Hartmann numbers
Authors: Krasnov Dmitry , Zikanov Oleg , Boeck Thomas 
Published: July 2012

AbstractHigh-resolution direct numerical simulations are conducted to analyse turbulent states of the flow of an electrically conducting fluid in a duct of square cross-section with electrically insulating walls and imposed transverse magnetic field. The Reynolds number of the flow is $1{0}^{5} $ and the Hartmann number varies from $0$ to $400$. It is found that there is a broad range of Hartmann numbers in which the flow is neither laminar nor fully turbulent, but has laminar core, Hartmann boundary layers and turbulent zones near the walls parallel to the magnetic field. Analysis of turbulent fluctuations shows that each zone consists of two layers: the boundary layer near the wall characterized by small-scale turbulence and the outer layer dominated by large-scale vortical structures strongly elongated in the direction of the magnetic field. We also find a peculiar scaling of the mean velocity, according to which the reciprocal von Kármán coefficient grows nearly linearly with the distance to the wall.
Numerical solution of unsteady boundary-layer separation in supersonic flow: upstream moving wall
Authors: Yapalparvi R. , Van Dommelen L. L. 
Published: July 2012

AbstractThis paper is an extension of work on separation from a downstream moving wall by Ruban et al. (J. Fluid. Mech., vol. 678, 2011, pp. 124–155) and is in particular concerned with the boundary-layer separation in unsteady two-dimensional laminar supersonic flow. In a frame attached to the wall, the separation is assumed to be provoked by a shock wave impinging upon the boundary layer at a point that moves downstream with a non-dimensional speed which is assumed to be of order ${\mathit{Re}}^{\ensuremath{-} 1/ 8} $ where $\mathit{Re}$ is the Reynolds number. In the coordinate system of the shock however, the wall moves upstream. The strength of the shock and its speed are allowed to vary with time on a characteristic time scale that is large compared to ${\mathit{Re}}^{\ensuremath{-} 1/ 4} $. The ‘triple-deck’ model is used to describe the interaction process. The governing equations of the interaction problem can be derived from the Navier–Stokes equations in the limit $\mathit{Re}\ensuremath{\rightarrow} \infty $. The numerical solutions are obtained using a combination of finite differences along the streamwise direction and Chebyshev collocation along the normal direction in conjunction with Newton linearization. In the present study with the wall moving upstream, the evidence is inconclusive regarding the so-called ‘Moore–Rott–Sears’ criterion being satisfied. Instead it is observed that the pressure rise from its initial value is very slow and that a recirculation region forms, the upstream part of which is wedge-shaped, as also observed in turbulent marginal separation for large values of angle of attack.
Adherence to a healthy Nordic food index is associated with a lower incidence of colorectal cancer in women: The Diet, Cancer and Health cohort study
Authors: Kyrø Cecilie , Skeie Guri , Loft Steffen , Overvad Kim , Christensen Jane , Tjønneland Anne , Olsen Anja 
Published: July 2012

Colorectal cancer (CRC) is a multi-factorial disease in which diet is believed to play a role. Little is known about the health effects of specific regional diets. The Nordic diet is high in fat and sugar but also includes a range of traditional products with anticipated health-promoting effects. The aim of this cohort study was to determine whether a healthy Nordic food index consisting of fish, cabbage, rye bread, oatmeal, apples, pears and root vegetables was related to CRC incidence. Data were obtained from a prospective cohort study of 57 053 Danish men and women aged 50–64 years, of whom 1025 developed CRC (13 years' follow-up). Incidence rate ratios (IRR) with 95 % CI were calculated from Cox proportional hazard models. Women who strongly adhered to a healthy Nordic food index had a 35 % lower incidence of CRC than women with poor adherence (adjusted IRR, 0·65; 95 % CI 0·46, 0·94); a similar tendency was found for men. Women had a 9 % lower incidence of CRC per point adherence to the healthy Nordic food index, but no significant effect was found for men. A regional diet based on healthy Nordic food items was therefore associated with a lower incidence of CRC in women. The protective effect was of the same magnitude as previously found for the Mediterranean diet, suggesting that healthy regional diets should be promoted in order to ensure health; this will also preserve cultural heredity and the environment.
Housing data-based socioeconomic index and risk of invasive pneumococcal disease: an exploratory study
Authors: JOHNSON M. D. , URM S. H. , JUNG J. A. , YUN H. D. , MUNITZ G. E. , TSIGRELIS C. , BADDOUR L. M. , JUHN Y. J. 
Published: July 2012

SUMMARYWe previously developed and validated an index of socioeconomic status (SES) termed HOUSES (housing-based index ofsocioeconomicstatus) based on real property data. In this study, we assessed whether HOUSES overcomes the absence of SES measures in medical records and is associated with risk of invasive pneumococcal disease (IPD) in children. We conducted a population-based case-control study of children in Olmsted County, MN, diagnosed with IPD (1995–2005). Each case was age- and gender-matched to two controls. HOUSES was derived using a previously reported algorithm from publicly available housing attributes (the higher HOUSES, the higher the SES). HOUSES was available for 92·3% (n = 97) and maternal education level for 43% (n = 45). HOUSES was inversely associated with risk of IPD in unmatched analysis [odds ratio (OR) 0·22, 95% confidence interval (CI) 0·05–0·89,P = 0·034], whereas maternal education was not (OR 0·77, 95% CI 0·50–1·19,P = 0·24). HOUSES may be useful for overcoming a paucity of conventional SES measures in commonly used datasets in epidemiological research.
Annual cycles of pressure, temperature, absolute humidity and precipitable water from the radiosoundings performed at Dome C, Antarctica, over the 2005–2009 period
Authors: Tomasi Claudio , Petkov Boyan H. , Benedetti Elena 
Published: July 2012

AbstractA four-year set of vertical profiles of pressure, temperature and relative humidity derived from 1113 radiosoundings performed at Dome C (Antarctica) at 12h00 UT of each day, from late March 2005 to the end of March 2009, was examined by following a complex procedure for removing the most important lag errors and dry biases from the temperature and moisture data. The analysis provides evidence of annual cycles over the four years, characterizing the pressure and temperature conditions at the surface and at the various troposphere and low stratosphere levels, with maxima in summer and wide minima in winter for both parameters. Specific studies of the thermal parameters characterizing the ground layer and the tropopause region are also presented to describe their annual average variations. The analysis of moisture parameters indicates that absolute humidity varies regularly with season within the low troposphere, presenting well marked peaks in the summer months. Consequently, precipitable water was found to vary regularly during the year, from values of 0.2–0.4 mm in the winter to more than 0.6 mm in summer. The main year-to-year variations characterizing the monthly mean vertical profiles of pressure, temperature and moisture parameters are also described.
Mapping of seasonal freeze‐thaw transitions across the pan‐Arctic land and sea ice domains with satellite radar
Authors: Mortin J. , Schrøder T. M. , Walløe Hansen A. , Holt B. , McDonald K. C. 
Published: July 2012

To monitor the pan‐Arctic seasonal freeze‐thaw transitions of the land surface and sea ice, we analyze daily backscatter data from satellite scatterometry to examine the time series on an annual basis by applying an optimal edge detection scheme, and iterate against an internal median climatology to mitigate unreasonable outliers. By applying this novel algorithm to resolution‐enhanced QuikSCAT data from 1999 to 2009, we have mapped a decade of seasonal freeze‐thaw transitions across the landmass and sea ice north of 60°N at a spatial resolution better than 5 km. The data set has been validated against surface air temperature measurements and snow depth obtained from a distributed network of weather stations and drift buoys. Most retrieved timings from surface and QuikSCAT measurements agree to less than a week at thaw transition for both land and sea ice and at freeze transition for sea ice, indicating successful retrieval over a range of surface covers. While the spatial pattern of freeze‐thaw transition changes substantially from year to year, the interannual variability of the mean transition timing over a particular surface is small.
PDIp is a major intracellular oestrogen-storage protein that modulates tissue levels of oestrogen in the pancreas
Authors: Fu Xinmiao , Wang Pan , Fukui Masayuki , Long Cheng , Yin Linxiang , Choi Hye Joung , Zhu Bao Ting 
Published: July 2012

E2 (17β-oestradiol), a female sex hormone, has important biological functions in a woman's body. The pancreas, often considered a non-classical E2-targeting organ, is known to be functionally regulated by E2, but little is known about how oestrogen actions are regulated in this organ. In the present study we report that PDIp (pancreas-specific protein disulfide isomerase), a protein-folding catalyst, can act as a major intracellular E2 storage protein in a rat model to modulate the pancreatic tissue level, metabolism and action of E2. The purified endogenous PDIp from both rat and human pancreatic tissues can bind E2 with a Kd value of approximately 150 nM. The endogenous PDIp-bound E2 accounts for over 80% of the total protein-bound E2 present in rat and human pancreatic tissues, and this binding protects E2 from metabolic disposition and prolongs its duration of action. Importantly, we showed in ovariectomized female rats that the E2 level in the pancreas reaches its highest level (9-fold increase over its basal level) at 24–48 h after a single injection of E2, and even at 96 h its level is still approximately 5-fold higher. In contrast, the E2 level in the uterus quickly returns to its basal level at 48 h after reaching its maximal level (approximately 2-fold increase) at 24 h. Taken together, these results show for the first time that PDIp is a predominant intracellular oestrogen storage protein in the pancreas, which offers novel mechanistic insights into the accumulation and action of oestrogen inside pancreatic cells.
Magnetostriction and magnetic texture to 100.75 Tesla in frustrated SrCu
2
(BO
3
)
2
Authors: Jaime Marcelo , Daou Ramzy , Crooker Scott A. , Weickert Franziska , Uchida Atsuko , Feiguin Adrian E. , Batista Cristian D. , Dabkowska Hanna A. , Gaulin Bruce D. 
Published: July 2012

Strong geometrical frustration in magnets leads to exotic states such as spin liquids, spin supersolids, and complex magnetic textures. SrCu
2
(BO
3
)
2
, a spin-1/2 Heisenberg antiferromagnet in the archetypical Shastry–Sutherland lattice, exhibits a rich spectrum of magnetization plateaus and stripe-like magnetic textures in applied fields. The structure of these plateaus is still highly controversial due to the intrinsic complexity associated with frustration and competing length scales. We discover magnetic textures in SrCu
2
(BO
3
)
2
via magnetostriction and magnetocaloric measurements in fields up to 100.75 T. In addition to observing low-field fine structure with unprecedented resolution, the data also reveal lattice responses at 73.6 T and at 82 T that we attribute, using a controlled density matrix renormalization group approach, to a unanticipated 2/5 plateau and to the long-predicted 1/2 plateau.
Correlating the magic numbers of inorganic nanomolecular assemblies with a
{Pd

84

}
molecular-ring Rosetta Stone
Authors: Xu Feng , Miras Haralampos N. , Scullion Rachel A. , Long De-Liang , Thiel Johannes , Cronin Leroy 
Published: July 2012

Molecular self-assembly has often been suggested as the ultimate route for the bottom-up construction of building blocks atom-by-atom for functional nanotechnology, yet structural design or prediction of nanomolecular assemblies is still far from reach. Whereas nature uses complex machinery such as the ribosome, chemists use painstakingly engineered step-by-step approaches to build complex molecules but the size and complexity of such molecules, not to mention the accessible yields, can be limited. Herein we present the discovery of a palladium oxometalate
{Pd

84

}
-ring cluster 3.3 nm in diameter; [Pd
84
O
42
(OAc)
28
(PO
4
)
42
]
70-
(
{Pd

84

}
≡
{Pd

12

}

7

) that is formed in water just by mixing two reagents at room temperature, giving crystals of the compound in just a few days. The structure of the
{Pd

84

}
-ring has sevenfold symmetry, comprises 196 building blocks, and we also show, using mass spectrometry, that a large library of other related nanostructures is present in solution. Finally, by analysis of the symmetry and the building block library that construct the
{Pd

84

}
we show that the correlation of the symmetry, subunit number, and overall cluster nuclearity can be used as a “Rosetta Stone” to rationalize the “magic numbers” defining a number of other systems. This is because the discovery of
{Pd

84

}
allows the relationship between seemingly unrelated families of molecular inorganic nanosystems to be decoded from the overall cluster magic-number nuclearity, to the symmetry and building blocks that define such structures allowing the prediction of other members of these nanocluster families.
Observationally constrained estimates of carbonaceous aerosol radiative forcing
Authors: Chung Chul E. , Ramanathan V. , Decremer Damien 
Published: July 2012

Carbonaceous aerosols (CA) emitted by fossil and biomass fuels consist of black carbon (BC), a strong absorber of solar radiation, and organic matter (OM). OM scatters as well as absorbs solar radiation. The absorbing component of OM, which is ignored in most climate models, is referred to as brown carbon (BrC). Model estimates of the global CA radiative forcing range from 0 to 0.7 Wm-2, to be compared with the Intergovernmental Panel on Climate Change’s estimate for the pre-Industrial to the present net radiative forcing of about 1.6 Wm-2. This study provides a model-independent, observationally based estimate of the CA direct radiative forcing. Ground-based aerosol network data is integrated with field data and satellite-based aerosol observations to provide a decadal (2001 through 2009) global view of the CA optical properties and direct radiative forcing. The estimated global CA direct radiative effect is about 0.75 Wm-2(0.5 to 1.0). This study identifies the global importance of BrC, which is shown to contribute about 20% to 550-nm CA solar absorption globally. Because of the inclusion of BrC, the net effect of OM is close to zero and the CA forcing is nearly equal to that of BC. The CA direct radiative forcing is estimated to be about 0.65 (0.5 to about 0.8) Wm-2, thus comparable to or exceeding that by methane. Caused in part by BrC absorption, CAs have a net warming effect even over open biomass-burning regions in Africa and the Amazon.
High-throughput single-microparticle imaging flow analyzer
Authors: Goda Keisuke , Ayazi Ali , Gossett Daniel R. , Sadasivam Jagannath , Lonappan Cejo K. , Sollier Elodie , Fard Ali M. , Hur Soojung Claire , Adam Jost , Murray Coleman , Wang Chao , Brackbill Nora , Di Carlo Dino , Jalali Bahram 
Published: July 2012

Optical microscopy is one of the most widely used diagnostic methods in scientific, industrial, and biomedical applications. However, while useful for detailed examination of a small number (< 10,000) of microscopic entities, conventional optical microscopy is incapable of statistically relevant screening of large populations (> 100,000,000) with high precision due to its low throughput and limited digital memory size. We present an automated flow-through single-particle optical microscope that overcomes this limitation by performing sensitive blur-free image acquisition and nonstop real-time image-recording and classification of microparticles during high-speed flow. This is made possible by integrating ultrafast optical imaging technology, self-focusing microfluidic technology, optoelectronic communication technology, and information technology. To show the system’s utility, we demonstrate high-throughput image-based screening of budding yeast and rare breast cancer cells in blood with an unprecedented throughput of 100,000 particles/s and a record false positive rate of one in a million.
Staphylococcus aureus Colonization before Infection Is Not Associated with Mortality among S. aureus-infected Patients: A Meta-analysis
Authors: Schweizer Marin L. , Bossen Ann , McDanel Jennifer S. , Dennis Leslie K. 
Published: July 2012

Background and Objective.The literature is conflicted as to whether people colonized with Staphylococcus aureus are at an increased risk of mortality. The aim of this meta-analysis was to review and analyze the current literature to determine whether prior history of S. aureus colonization is associated with mortality among S. aureus-infected patients.Methods.The PUBMED databases were searched with keywords related to S. aureus colonization and mortality. After reviewing 380 article abstracts and 59 articles in detail, only 7 studies had data on the association between S. aureus colonization and mortality among S. aureus-infected patients. Crude estimates of study odds ratios (ORs) were calculated on the basis of data from subset analyses. We pooled crude ORs from the 7 studies using a random-effects model. Woolf's test for heterogeneity was assessed.Results.When all studies were pooled in a random-effects model, no association between S. aureus colonization and mortality among S. aureus-infected patients was seen (pooled OR, 1.08 [95% confidence interval (CI), 0.32–3.66]; n = 7; heterogeneity P = .05). When the analyses were restricted to infection-attributable mortality, the association between colonization and mortality among S. aureus-infected patients was not statistically significant (pooled OR, 0.42 [95% CI, 0.15–1.21]; n = 4; heterogeneity P = .28).Conclusions.S. aureus colonization was not associated with mortality among patients who developed an S. aureus infection. Interventions to decolonize S. aureus carriers may prevent S. aureus infections but may not be sufficient to prevent mortality.
A Toolkit for Monitoring Hospital-Acquired Bloodstream Infection in Neonatal Intensive Care
Authors: Leighton Pamela , Cortina-Borja Mario , Millar Michael , Kempley Stephen , Gilbert Ruth 
Published: July 2012

Objective.In neonatal intensive care units (NICUs), monitoring hospital-acquired bloodstream infection (BSI) is critical to alert clinicians to variations in the incidence of infection between units and over time. We demonstrate a toolkit of monitoring techniques that account for case mix and could be implemented using routinely available clinical data. This toolkit could enable quality of care comparisons between hospitals to facilitate the sharing of improved practices.Design.Prospective study over 4 years.Setting and Patients.Babies admitted to 2 tertiary London NICUs.Methods.We derived expected numbers of BSI episodes using a Poisson regression risk model adjusting for variations in birth weight, transfers to the NICU from other hospitals, postnatal age, and days spent at each National Health Service level of care. We compared observed and expected numbers of BSI episodes using 2 monitoring techniques: standardized infection ratios (SIRs) and the sequential probability ratio test (SPRT).Results.Using the SIR method, observed BSI incidence increased over expected incidence in 2002 at both NICUs, but this increase did not reach statistical significance at the 1% level. Using the SPRT method, neither unit showed a clinically important increase or decrease, defined as a 30% deviation from expected incidence.Conclusions.Risk-adjusted BSI monitoring can be performed using routine hospital data. NICUs could use SIRs for an annual look back at infection incidence and SPRTs for prospective, quarterly monitoring. The SIR and the SPRT methods have different strengths, and both could help clinicians improve infection control and patient care in NICUs.