bluuebunny/crossref_metadata_2025 huggingface dataset:
Validity of two short screeners for diet quality in time-limited settings
Authors: Schröder Helmut , Benitez Arciniega Alejandra , Soler Cristina , Covas Maria-Isabel , Baena-Díez José Miguel , Marrugat Jaume
Published: August 2011

Objective

An urgent need in dietary assessment is the development of short tools that provide valid assessments of dietary quality for use in time-limited settings. The present study assessed concurrent and construct validity of the short Diet Quality Screener (sDQS) and brief Mediterranean Diet Screener (bMDSC) questionnaires.

Design

Relative validity was measured by comparing three dietary quality indices – the Diet Quality Index (DQI), the modified Mediterranean Diet Score (mMDS) and the Antioxidant Score (ANTOX-S) – derived from the two questionnaires with those from multiple 24 h recalls over 12 months. Construct validity was demonstrated by correlations between average nutrient intake recorded on multiple 24 h recalls and the DQI, mMDS and ANTOX-S derived by the short screeners.

Setting

Both short questionnaires were administered to 102 participants recruited from a population-based survey in Spain.

Results

DQI, mMDS and ANTOX-S correlated (P < 0·001) with the corresponding 24 h recall indices (r = 0·61, 0·40 and 0·45, respectively). Limits of agreement lay between 96 and 126 %, 59 and 144 % and 61 and 118 % for the DQI, ANTOX-S and mMDS, respectively. Dietary intakes of fibre, vitamin C, vitamin E, Mg and K reported on the 24 h recalls were positively associated (P < 0·04) with the DQI, mMDS and ANTOX-S indices.

Conclusions

The sDQS and bMDSC provide reasonable approximations to food-based dietary indices and accurately situate subjects within the indices constructed for the present validation study.
Serum retinol in 1–6-year-old children from a low socio-economic South African community with a high intake of liver: implications for blanket vitamin A supplementation
Authors: van Stuijvenberg Martha E , Schoeman Serina E , Lombard Carl J , Dhansay Muhammad A
Published: August 2011

Objective

To assess serum retinol, liver intake patterns, breast-feeding history and anthropometric status in pre-school children of a low socio-economic community where liver is regularly consumed.

Design

Cross-sectional study.

Setting

Northern Cape Province, South Africa.

Subjects

Children aged 1–6 years (n243) who attended the local primary health-care facility and had not received a vitamin A supplement in the 6 months preceding the study. Non-pregnant female caregivers (n225), below 50 years of age, were also assessed.

Results

Despite stunting, underweight and wasting being prevalent in 40·5 %, 23·1 % and 8·4 % of the children, only 5·8 % had serum retinol concentrations < 20 μg/dl, which is in sharp contrast to the national prevalence of 63·6 %. None of the caregivers were vitamin A deficient. Liver was eaten by 89·2 % of children, with 87 % of households eating liver at least once monthly and 30 % eating it at least once weekly; liver was introduced into the diet of the children at a median age of 18 months. Ninety-three per cent of the children were being breast-fed or had been breast-fed in the past; children were breast-fed to a median age of 18 months. A significant negative correlation was found between educational level of the caregiver and frequency of liver intake (r= −0·143,P=0·032). There was no correlation between serum retinol and indicators of anthropometric or socio-economic status.

Conclusions

The blanket approach in applying the national vitamin A supplementation programme may not be appropriate for all areas in the country, even though the community may be poor and undernourished.
Myofibroblast differentiation and survival in fibrotic disease
Authors: Kis Kornelia , Liu Xiaoqiu , Hagood James S.
Published: August 2011

During wound healing, contractile fibroblasts called myofibroblasts regulate the formation and contraction of granulation tissue; however, pathological and persistent myofibroblast activation, which occurs in hypertrophic scars or tissue fibrosis, results in a loss of function. Many reviews outline the cellular and molecular features of myofibroblasts and their roles in a variety of diseases. This review focuses on the origins of myofibroblasts and the factors that control their differentiation and prolonged survival in fibrotic tissues. Pulmonary fibrosis is used to illustrate many key points, but examples from other tissues and models are also included. Myofibroblasts originate mostly from tissue-resident fibroblasts, and also from epithelial and endothelial cells or other mesenchymal precursors. Their differentiation is influenced by cytokines, growth factors, extracellular matrix composition and stiffness, and cell surface molecules such as proteoglycans and THY1, among other factors. Many of these effects are modulated by cell contraction. Myofibroblasts resist programmed cell death, which promotes their accumulation in fibrotic tissues. The cause of resistance to apoptosis in myofibroblasts is under ongoing investigation, but many of the same stimuli that regulate their differentiation are involved. The contributions of oxidative stress, the WNT–β-catenin pathway and PPARγ to myofibroblast differentiation and survival are increasingly appreciated.
Water resources implications of integrating malaria control into the operation of an Ethiopian dam
Authors: Reis Julia , Culver Teresa B. , McCartney Matthew , Lautze Jonathan , Kibret Solomon
Published: August 2011

This paper investigates the water resources implications of using a method of hydrological control to reduce malaria around the Koka reservoir in central Ethiopia. This method is based on recent findings that malaria is transmitted from the shoreline of the Koka reservoir, and on a similar method that was used to control malaria some 80 yr ago in the United States. To assess the feasibility of implementing hydrological control at Koka, we considered the potential impact of the modified management regime on the benefits derived from current uses of the reservoir water (i.e., hydropower, irrigation, flood control, water supply, and downstream environmental flows). We used the HEC‐ResSim model to simulate lowering the reservoir by a rate designed to disrupt larval development, which is expected to reduce the abundance of adult mosquito vectors and therefore reduce malaria transmission during the season in which transmission of the disease peaks. A comparison was made of major reservoir uses with and without the malaria control measure. In the 26‐yr simulation, application of the malaria control measure increased total average annual electricity generation from 87.6 GWh × y−1 to 92.2 GWh × y−1 (i.e., a 5.3% increase) but resulted in a small decline in firm power generation (i.e., guaranteed at 99.5% reliability) from 4.16 MW to 4.15 MW (i.e., a 0.2% decrease). Application of the malaria control measure did not impact the ability of the reservoir to meet downstream irrigation demand and reduced the number of days of downstream flooding from 28 to 24 d. These results indicate that targeted use of hydrological control for malaria vector management could be undertaken without sacrificing the key benefits of reservoir operation.
Microvascular Free Tissue Transfer in the Reconstruction of Scalp and Lateral Temporal Bone Defects
Authors: O'Connell Daniel A. , Teng Marita S. , Mendez Eduardo , Futran Neal D.
Published: August 2011

Defects of the scalp and lateral temporal bone (LTB) represent a unique challenge to the reconstructive surgeon. Simple reconstructive methods such as skin grafts, locoregional flaps, or tissue expanders are often not feasible due to a myriad of reasons. Vascularized free tissue transfer coverage offers distinct advantages in managing these defects. A retrospective case series was performed on all patients at the University of Washington Medical Center who had scalp or LTB defects reconstructed with free tissue transfer from May 1996 to July 2009. Cases were analyzed for defect characteristics, flap type, vessel selection, radiation status, dural exposure, complications, and outcomes. Sixty-eight free flaps were performed in 65 patients with scalp or LTB defects. Twenty-two resections included craniotomy, and 48 patients had pre- or postoperative radiation. Defects ranged from 6 to 836 cm2. All flaps (46 latissimus, 11 rectus, 4 radial forearm, 6 anterolateral thigh, and 1 omental) were transferred successfully. Vein grafts were required in five cases. Complications included delayed flap failure requiring secondary reconstruction, neck hematoma, venous thrombosis, skull base infection, large wound dehiscence, small wound dehiscence, donor site hematoma and seroma, and cerebrospinal fluid leak. Cosmetic results were consistent and durable. Microvascular free tissue transfer is a safe, reliable method of reconstructing scalp and LTB defects and offers favorable cosmetic results. We favor the use of latissimus muscle-only flap with skin graft coverage for large scalp defects and rectus or anterolateral thigh free flaps for lateral temporal bone defects.
Large area quasi-free standing monolayer graphene on 3C-SiC(111)
Authors: Coletti C. , Emtsev K. V. , Zakharov A. A. , Ouisse T. , Chaussende D. , Starke U.
Published: August 2011

Large scale, homogeneous quasi-free standing monolayer graphene is obtained on cubic silicon carbide, i.e., the 3C-SiC(111) surface, which represents an appealing and cost effective platform for graphene growth. The quasi-free monolayer is produced by intercalation of hydrogen under the interfacial, (63×63)R30 °-reconstructed carbon layer. After intercalation, angle resolved photoemission spectroscopy reveals sharp linear π-bands. The decoupling of graphene from the substrate is identified by x-ray photoemission spectroscopy and low energy electron diffraction. Atomic force microscopy and low energy electron microscopy demonstrate that homogeneous monolayer domains extend over areas of hundreds of square-micrometers.
Evaluation of thermal efficiency of oscillating-bed solar dryer through drying of sunflower seeds
Authors: Shanmugam S. , Kumar P. , Veerappan AR.
Published: August 2011

Quite a number of solar dryers have been reported for drying of different agricultural produce and products. Few dryers have their bed oscillated. A solar dryer, the bed of which is oscillated at different frequencies is presented in this paper. This paper also explains the drying methodology, variation in relative humidity, and removal of moisture content from sunflower seeds. It is possible to dry 31.36 kg of sunflower seeds to the average moisture level of 7.9% which is in the acceptable level of moisture content of less than 10% in just 8 h. The average thermal efficiency of the solar dryer is 30.1%.
Monte Carlo simulation study of spin transport in single layer graphene
Authors: Ghosh Bahniman , Misra Soumya
Published: August 2011

Spin transport in single layer graphene is studied in this work using a semiclassical Monte Carlo simulation, and a comparison is made to bi-layer graphene. Spin relaxation is modeled using the D’yakonov-Perel and Elliot-Yafet mechanisms. It is shown that bi-layer graphene has a higher spin relaxation length compared to single layer graphene, and this has also been observed experimentally. An explanation of this difference is given in terms of the band structures of the two materials.
Electron pair density in the lowest 1$\Sigma _u^+$Σu+ and 1$\Sigma _g^+$Σg+ states of H2
Authors: Wang Jian , Kim Kwang S. , Baerends Evert Jan
Published: August 2011

We demonstrate and advocate the use of observable quantities derived from the two-electron reduced density matrix – pair densities, conditional densities, and exchange-correlation holes – as signatures of the type of electron correlation in a chemical bond. The prototype cases of the lowest 1\documentclass[12pt]{minimal}\begin{document}$\Sigma _u^+$\end{document}Σu+ and 1\documentclass[12pt]{minimal}\begin{document}$\Sigma _g^+$\end{document}Σg+ states of H2, which exhibit large variation in types of bonding, ranging from strongly ionic to covalent, are discussed. Both the excited 1\documentclass[12pt]{minimal}\begin{document}$\Sigma _g^+$\end{document}Σg+ and 1\documentclass[12pt]{minimal}\begin{document}$\Sigma _u^+$\end{document}Σu+ states have been interpreted as essentially consisting of (natural) orbital configurations with an inner electron in a contracted 1sσg orbital and an outer electron in a diffuse (united atom type, Rydberg) orbital. We show that nevertheless totally different correlation behavior is encountered in various states when comparing them at a common internuclear distance. Also when following one state along the internuclear distance coordinate, strong variation in correlation behavior is observed, as expected. Switches between ionic to covalent character of a state occur till very large distances (40 bohrs for states approaching the 1s3ℓ asymptotic limit, and 282 bohrs for states approaching the 1s4ℓ limit).
Temperature dependence of surface phonon polaritons from a quartz grating
Authors: Hafeli Andrew K. , Rephaeli Eden , Fan Shanhui , Cahill David G. , Tiwald Thomas E.
Published: August 2011

We report the temperature dependence of the surface phonon polariton (SPhP) spectra of α-SiO2 (quartz), propagated to the far-field by a grating, in the temperature range between 300 K and 800 K. Room temperature data for a 670 nm deep grating are compared to a simulated spectrum using a finite-difference frequency-domain approach. The inputs to the simulation are the dielectric functions measured by infrared ellipsometry and modeled as a set of damped oscillators. The simulated spectra are in good agreement with experiment. The width of the SPhP reflectivity dip depends on the depth of the grating. For a grating depth of 280 nm, the width of the reflectivity dip in the temperature range 300 < T < 800 K is comparable to what is expected for the SPhP excitations of a flat surface. For a grating depth of 670 nm, the width of the reflectivity dip increases significantly due to coupling to far-field radiation.
Nonvolatile, reversible electric-field controlled switching of remanent magnetization in multifunctional ferromagnetic/ferroelectric hybrids
Authors: Brandlmaier A. , Geprägs S. , Woltersdorf G. , Gross R. , Goennenwein S. T. B.
Published: August 2011

In spin-mechanics, the magnetoelastic coupling in ferromagnetic/ferroelectric hybrid devices is exploited in order to realize an electric-voltage control of magnetization orientation. To this end, different voltage-induced elastic strain states are used to generate different magnetization orientations. In our approach, we take advantage of the hysteretic expansion and contraction of a commercial piezoelectric actuator as a function of electrical voltage to deterministically select one of two electro-remanent elastic strain states. We investigate the resulting magnetic response in a nickel thin film/piezoelectric actuator hybrid device at room temperature, using simultaneous magneto-optical Kerr effect and magnetotransport measurements. The magnetic properties of the hybrid can be consistently described in a macrospin model, i.e., in terms of a single magnetic domain. At zero external magnetic field, the magnetization orientation in the two electro-remanent strain states differs by 15°, which corresponds to a magnetoresistance change of 0.5%. These results demonstrate that the spin-mechanics scheme indeed enables a nonvolatile electrically read- and writable memory bit where the information is encoded in a magnetic property.
Thermopower and thermal conductivity of Kondo lattice CeCu4Al
Authors: Falkowski M. , Kowalczyk A.
Published: August 2011

The thermal conductivity κ and thermopower S are discussed for the Kondo lattice CeCu4Al compound. Thermopower is positive over the whole temperature range and below Tmax = 27 K falls rapidly. Based on a simple band model the position and width of the 4f peak nearest to the Fermi level have been estimated. The measured thermal conductivity of the CeCu4Al compound increases almost linearly with increasing temperature. The values of L/L0 for CeCu4Al are typical of heavy fermion compounds. At low temperatures the magnetic field has the strongest effect on the thermopower and thermal conductivity. The maximum value of S(T) and temperature of the peak, Tmax are independent of applied magnetic field.
Cs atoms on helium nanodroplets and the immersion of Cs+ into the nanodroplet
Authors: Theisen Moritz , Lackner Florian , Ernst Wolfgang E.
Published: August 2011

We report the non-desorption of cesium (Cs) atoms on the surface of helium nanodroplets (\documentclass[12pt]{minimal}\begin{document}${\rm He}_{\text{N}}$\end{document} He N) in their 62P1/2 (2Π1/2) state upon photo-excitation as well as the immersion of Cs+ into the \documentclass[12pt]{minimal}\begin{document}${\rm He}_{\text{N}}$\end{document} He N upon photo-ionization via the 62P1/2 (2Π1/2) state. Cesium atoms on the surface of helium nanodroplets are excited with a laser to the 62P states. We compare laser-induced fluorescence (LIF) spectra with a desorption-sensitive method (Langmuir-Taylor detection) for different excitation energies. Dispersed fluorescence spectra show a broadening of the emission spectrum only when Cs-\documentclass[12pt]{minimal}\begin{document}${\rm He}_{\text{N}}$\end{document} He N is excited with photon energies close to the atomic D1-line, which implies an attractive character of the excited state system (Cs*-\documentclass[12pt]{minimal}\begin{document}${\rm He}_{\text{N}}$\end{document} He N) potential energy curve. The experimental data are compared with a calculation of the potential energy curves of the Cs atom as a function of its distance R from the center of the \documentclass[12pt]{minimal}\begin{document}${\rm He}_{\text{N}}$\end{document} He N in a pseudo-diatomic model. Calculated Franck-Condon factors for emission from the 62P1/2 (2Π1/2) to the 62S1/2 (2Σ1/2) state help to explain the experimental data. The stability of the Cs*-\documentclass[12pt]{minimal}\begin{document}${\rm He}_{\text{N}}$\end{document} He N system allows to form Cs+ snowballs in the \documentclass[12pt]{minimal}\begin{document}${\rm He}_{\text{N}}$\end{document} He N, where we use the non-desorbing 62P1/2 (2Π1/2) state as a springboard for ionization in a two-step ionization scheme. Subsequent immersion of positively charged Cs ions is observed in time-of-flight mass spectra, where masses up to several thousand amu were monitored. Only ionization via the 62P1/2 (2Π1/2) state gives rise to a very high yield of immersed Cs+ in contrast to an ionization scheme via the 62P3/2 (2Π3/2) state. When resonant two-photon ionization is applied to cesium dimers on He droplets, \documentclass[12pt]{minimal}\begin{document}${\rm Cs}_2^+$\end{document} Cs 2+-\documentclass[12pt]{minimal}\begin{document}${\rm He}_{\text{N}}$\end{document} He N aggregates are observed in time-of-flight mass spectra.
Structural, optical and magnetic properties of polycrystalline BaTi1−xFexO3 ceramics
Authors: Dang N. V. , Thanh T. D. , Hong L. V. , Lam V. D. , Phan The-Long
Published: August 2011

Polycrystalline BaTi1−xFexO3 ceramics have been prepared by conventional solid-state reaction. Their structural, optical and magnetic properties are then studied by means of x-ray diffraction (XRD), Raman scattering (RS) and absorption spectrometers, and a physical properties measurement system. Detailed analyses of XRD patterns and RS spectra reveal the phase separation of the tetragonal-hexagonal structure at a threshold concentration of x = 0.005. The increase in the Fe-doping content (x) leads to development of the hexagonal phase. Magnetic measurements prove that many BaTi1−xFexO3 samples exhibit the room-temperature ferromagnetic order, excepting the samples with x = 0.02–0.06. The ferromagnetism depends strongly on concentration of Fe impurities. The nature of this ferromagnetism is discussed by means of the results of structural analyses and optical absorption spectra.
Reversible strain by physisorption in nanoporous gold
Authors: Detsi E. , Chen Z. G. , Vellinga W. P. , Onck P. R. , De Hosson J. T. M.
Published: August 2011

Reversible strain amplitudes up to 0.02% in response to a 15% change in relative humidity were detected in nanoporous gold. We show that the mechanism involved in dimensional changes during physisorption is associated with changes in the surface stress when molecules are adsorbed from the vapor phase onto the metal interface.
Mechanism of high luminous efficacy in plasma display panel with high secondary electron emission coefficient cathode material analyzed through three-dimensional fluid model simulation
Authors: Kwon Ohyung , Bae Hyun Sook , Jung Hae-Yoon , Lee Tae-Ho , Cheong Hee-Woon , Whang Ki-Woong
Published: August 2011

The mechanism to realize high luminous efficacy in a plasma display panel fabricated with a cathode material possessing a high secondary electron emission coefficient (γ) for Ne and Xe ions was studied via three-dimensional numerical simulation. When a high γ cathode material is used, the increased electron heating efficacy is responsible for increasing vacuum ultraviolet (VUV) efficacy with 10% Xe content gas. However, the continued availability of sufficient secondary electrons during the dynamic moving phase of the cathode sheath in which the electric field remains weakened causes increasing VUV efficacy with 30% Xe content gas. It was found that the improvement of the luminous efficacy of the plasma display panel with a high γ cathode material is maximized under the condition of high Xe content gas because of the simultaneous increase of the electron heating efficacy and Xe excitation efficacy.
Experimental study of a semi-passive ventilation grille with a feedback control system
Authors: D’Orazio A. , Fontana L. , Salata F.
Published: August 2011

The diffusion of window frames with low air permeability, due to the energy saving regulations, has implied in several cases the worsening of the indoor microclimate and air quality. On the other hand, air-tight window frames imply uncontrolled and too high air change rates. The mechanical ventilation not always is a practicable solution because of economic reasons and because it implies energy waste. Various Italian and European environmental and energetic laws take into consideration and promote the use of controlled natural ventilation, though this definition is not associated to well defined and tested technical solutions. An adequate solution can be achieved by using semi-passive self adjustable ventilation devices, able to ensure controlled changes of indoor air. In this paper, a semi-passive damper with a feedback control system is proposed and its behavior is investigated by means of experimental study. The presented semi-passive grille allows to control the air flow rate, injected into the room by natural or artificial pressure gradient, more effectively than the usual passive ventilation grilles made available by the present industrial production. However, since the semi-passive grille has a one-way flow, in the natural ventilation of a flat the proper functioning of the system could be ensured with a more complex configuration, with respect to the passive self-regulating grilles, able to limit the flow of fresh air in the presence of high levels of Δp; conversely, it could have widespread use in applications requiring a more accurate control of airflow in case of mechanical ventilation plants.
Enhanced exciton separation through negative energy band bending at grain boundaries of Cu2ZnSnSe4 thin-films
Authors: Jeong A. R. , Jo W. , Jung S. , Gwak J. , Yun J. H.
Published: August 2011

Local surface potential of Cu2ZnSnSe4 thin-films was investigated by Kelvin probe force microscopy. The surface potential profile across grain boundaries (GBs) shows a rise of 200–600 meV at GBs in a Cu-poor and Zn-poor film with 3.8% efficiency, which means positively charged GBs. In contrast, the GBs in a Cu-poor and Zn-rich film with 2% efficiency exhibit lowering of surface potential by 40 meV. The results indicate that GBs of Cu2ZnSnSe4 films play a role for exciton separation and governing defects for high efficiency could be not only CuZn but also VCu as explained theoretical predictions.
Role of wetting and nanoscale roughness on thermal conductance at liquid-solid interface
Authors: Wang Y. , Keblinski P.
Published: August 2011

Using non-equilibrium molecular dynamics simulations in which a temperature gradient is imposed, we determine the thermal resistance of a model liquid-solid interface with and without nanoscale roughness. Our simulations reveal that in both cases the key factor controlling interfacial thermal conductance is the strength of the bonding between liquid and solid atoms. In addition, we show that in the case of rough surfaces, the nanoscopic wetting-dewetting transition has a strong signature in the interfacial thermal conductance. Interestingly, the smooth and rough interfaces, despite distinct geometry, show quantitatively the same dependence of the interfacial conductance on the value of the interfacial adhesion.
Creation of arbitrary spectra with an acousto-optic modulator and an injection-locked diode laser
Authors: Lin Pei-Ying , Shiau Bor-Wen , Hsiao Ya-Fen , Chen Ying-Cheng
Published: August 2011

We use a double-passed acousto-optic modulator (AOM), driven by an arbitrary waveform generator to produce multiple frequency components for a laser with arbitrary frequency spacings. A programmed sequence containing various sections of radio-frequency sinusoidal signal at different frequency is applied to drive the AOM. The diffracted light is used to injection-lock a diode laser. The combined techniques allow us to generate the multi-line spectra for the diode laser with arbitrary frequency spacings in the range of 100 MHz at a relatively high output power of 80 mW and a small power variation of 2%. Such a light source can be used in the application for laser cooling of molecules.
Limiting mechanism of inversion channel mobility in Al-implanted lateral 4H-SiC metal-oxide semiconductor field-effect transistors
Authors: Frazzetto A. , Giannazzo F. , Fiorenza P. , Raineri V. , Roccaforte F.
Published: August 2011

The mechanism limiting the channel mobility in metal-oxide-semiconductor field-effect transistors (MOSFETs) fabricated in Al-implanted 4H-SiC is discussed comparing different post-implantation annealings. In spite of the improved interfacial morphology in carbon capped samples during annealing, the observed reduction of the mobility (from 40 to 24 cm2 V−1 s−1) suggests that interfacial roughness does not significantly impact the transport in the channel. Furthermore, the temperature dependence of the mobility demonstrates that Coulomb scattering is the main degradation mechanism due to the presence of trapped charges at the SiO2/SiC interface.
Non-invasive terahertz field imaging inside parallel plate waveguides
Authors: Iwaszczuk K. , Andryieuski A. , Lavrinenko A. , Zhang X.-C. , Jepsen P. U.
Published: August 2011

We present a non-invasive broadband air photonic method of imaging of the electric field of THz pulses propagating inside a tapered parallel plate waveguide. The method is based on field-enhanced second harmonic generation of the fundamental laser beam in an external electric field. We apply the technique to measure the frequency-dependent reflection coefficient at the end of the waveguide.
On biodiversity conservation and poverty traps
Authors: Barrett Christopher B. , Travis Alexander J. , Dasgupta Partha
Published: August 2011

This paper introduces a special feature on biodiversity conservation and poverty traps. We define and explain the core concepts and then identify four distinct classes of mechanisms that define important interlinkages between biodiversity and poverty. The multiplicity of candidate mechanisms underscores a major challenge in designing policy appropriate across settings. This framework is then used to introduce the ensuing set of papers, which empirically explore these various mechanisms linking poverty traps and biodiversity conservation.
Community Markets for Conservation (COMACO) links biodiversity conservation with sustainable improvements in livelihoods and food production
Authors: Lewis Dale , Bell Samuel D. , Fay John , Bothi Kim L. , Gatere Lydiah , Kabila Makando , Mukamba Mwangala , Matokwani Edwin , Mushimbalume Matthews , Moraru Carmen I. , Lehmann Johannes , Lassoie James , Wolfe David , Lee David R. , Buck Louise , Travis Alexander J.
Published: August 2011

In the Luangwa Valley, Zambia, persistent poverty and hunger present linked challenges to rural development and biodiversity conservation. Both household coping strategies and larger-scale economic development efforts have caused severe natural resource degradation that limits future economic opportunities and endangers ecosystem services. A model based on a business infrastructure has been developed to promote and maintain sustainable agricultural and natural resource management practices, leading to direct and indirect conservation outcomes. The Community Markets for Conservation (COMACO) model operates primarily with communities surrounding national parks, strengthening conservation benefits produced by these protected areas. COMACO first identifies the least food-secure households and trains them in sustainable agricultural practices that minimize threats to natural resources while meeting household needs. In addition, COMACO identifies people responsible for severe natural resource depletion and trains them to generate alternative income sources. In an effort to maintain compliance with these practices, COMACO provides extension support and access to high-value markets that would otherwise be inaccessible to participants. Because the model is continually evolving via adaptive management, success or failure of the model as a whole is difficult to quantify at this early stage. We therefore test specific hypotheses and present data documenting the stabilization of previously declining wildlife populations; the meeting of thresholds of productivity that give COMACO access to stable, high-value markets and progress toward economic self-sufficiency; and the adoption of sustainable agricultural practices by participants and other community members. Together, these findings describe a unique, business-oriented model for poverty alleviation, food production, and biodiversity conservation.
Random partitioning of molecules at cell division
Authors: Huh Dann , Paulsson Johan
Published: August 2011

Many RNAs, proteins, and organelles are present in such low numbers per cell that random segregation of individual copies causes large “partitioning errors” at cell division. Even symmetrically dividing cells can then by chance produce daughters with very different composition. The size of the errors depends on the segregation mechanism: Control systems can reduce low-abundance errors, but the segregation process can also be subject to upstream sources of randomness or spatial heterogeneities that create large errors despite high abundances. Here we mathematically demonstrate how partitioning errors arise for different types of segregation mechanisms and how errors can be greatly increased by upstream heterogeneity but remarkably hard to avoid through controlled partitioning. We also show that seemingly straightforward experiments cannot be straightforwardly interpreted because very different mechanisms produce identical fits and present an approach to deal with this problem by adding binomial counting noise and testing for convexity or concavity in the partitioning error as a function of the binomial thinning parameter. The results lay a conceptual groundwork for more effective studies of heterogeneity among growing and dividing cells, whether in microbes or in differentiating tissues.
PI3K/Akt signaling requires spatial compartmentalization in plasma membrane microdomains
Authors: Gao Xinxin , Lowry Pamela R. , Zhou Xin , Depry Charlene , Wei Zhikui , Wong G. William , Zhang Jin
Published: August 2011

Spatial compartmentalization of signaling pathway components generally defines the specificity and enhances the efficiency of signal transduction. The phosphatidylinositol 3-kinase (PI3K)/Akt pathway is known to be compartmentalized within plasma membrane microdomains; however, the underlying mechanisms and functional impact of this compartmentalization are not well understood. Here, we show that phosphoinositide-dependent kinase 1 is activated in membrane rafts in response to growth factors, whereas the negative regulator of the pathway, phosphatase and tensin homolog deleted on chromosome 10 (PTEN), is primarily localized in nonraft regions. Alteration of this compartmentalization, either by genetic targeting or ceramide-induced recruitment of PTEN to rafts, abolishes the activity of the entire pathway. These findings reveal critical steps in raft-mediated PI3K/Akt activation and demonstrate the essential role of membrane microdomain compartmentalization in enabling PI3K/Akt signaling. They further suggest that dysregulation of this compartmentalization may underlie pathological complications such as insulin resistance.
In situ molecular NMR picture of bioavailable calcium stabilized as amorphous CaCO3biomineral in crayfish gastroliths
Authors: Akiva-Tal Anat , Kababya Shifi , Balazs Yael S. , Glazer Lilah , Berman Amir , Sagi Amir , Schmidt Asher
Published: August 2011

Bioavailable calcium is maintained by some crustaceans, in particular freshwater crayfish, by stabilizing amorphous calcium carbonate (ACC) within reservoir organs—gastroliths, readily providing the Ca2+needed to build a new exoskeleton. Despite the key scientific and biomedical importance of the in situ molecular-level picture of biogenic ACC and its stabilization in a bioavailable form, its description has eluded efforts to date. Herein, using multinuclear NMR, we accomplish in situ molecular-level characterization of ACC withinintactgastroliths of the crayfishCherax quadricarinatus. In addition to the known CaCO3, chitin scaffold and inorganic phosphate (Pi), we identify within the gastrolith two primary metabolites, citrate and phosphoenolpyruvate (PEP) and quantify their abundance by applying solution NMR techniques to the gastrolith “soluble matrix.” The long-standing question on the physico-chemical state of ACC stabilizing, P-bearing moieties within the gastrolith is answered directly by the application of solid state rotational-echo double-resonance (REDOR) and transferred-echo double-resonance (TEDOR) NMR to the intact gastroliths: Pi and PEP are found molecularly dispersed throughout the ACC as a solid solution. Citrate carboxylates are found < 5 Åfrom a phosphate (intermolecular C⋯P distance), an interaction that must be mediated by Ca2+. The high abundance and extensive interactions of these molecules with the ACC matrix identify them as the central constituents stabilizing the bioavailable form of calcium. This study further emphasizes that it is imperative to characterize the intact biogenic CaCO3. Solid state NMR spectroscopy is shown to be a robust and accessible means of determining composition, internal structure, and molecular functionality in situ.
Trial-to-trial variability in the responses of neurons carries information about stimulus location in the rat whisker thalamus
Authors: Scaglione Alessandro , Moxon Karen A. , Aguilar Juan , Foffani Guglielmo
Published: August 2011

From the perspective of neural coding, the considerable trial-to-trial variability in the responses of neurons to sensory stimuli is puzzling. Trial-to-trial response variability is typically interpreted in terms of “noise” (i.e., it represents either intrinsic noise of the system or information unrelated to the stimuli). However, trial-to-trial response variability can be considerably different across stimuli, suggesting that it could also provide an important contribution to the information conveyed by the neural responses about the stimuli. To test this hypothesis, we addressed the problem of discriminating stimulus location from the spike-count responses of neurons recorded in the ventro-postero-medial (VPM) nucleus of the thalamus in anesthetized rats. Using a recently developed information theory approach, we verified that differences between stimuli in the trial-to-trial spike-count variability of the responses provided an important contribution to the overall information carried by the neurons. In addition, we found that the relatively reliable (sub-Poisson) firing regime of our VPM neurons was not only more informative, but also more redundant between neurons compared with a more variable (Poisson) firing regime with the same total number of spikes. The typical increase in trial-to-trial response variability from the periphery to the cortex could therefore serve as a strategy to reduce redundancy between neurons and promote efficient sparse coding distributed in large populations of neurons. Overall, our data suggest that the trial-to-trial response variability plays a critical role in establishing the trade-off between total information and redundancy between neurons in population codes.
Intersection of FOXO- and RUNX1-mediated gene expression programs in single breast epithelial cells during morphogenesis and tumor progression
Authors: Wang Lixin , Brugge Joan S. , Janes Kevin A.
Published: August 2011

Gene expression networks are complicated by the assortment of regulatory factors that bind DNA and modulate transcription combinatorially. Single-cell measurements can reveal biological mechanisms hidden by population averages, but their value has not been fully explored in the context of mRNA regulation. Here, we adapted a single-cell expression profiling technique to examine the gene expression program downstream of Forkhead box O (FOXO) transcription factors during 3D breast epithelial acinar morphogenesis. By analyzing patterns of mRNA fluctuations among individual matrix-attached epithelial cells, we found that a subset of FOXO target genes was jointly regulated by the transcription factor Runt-related transcription factor 1 (RUNX1). Knockdown of RUNX1 causes hyperproliferation and abnormal morphogenesis, both of which require normal FOXO function. Down-regulating RUNX1 and FOXOs simultaneously causes widespread oxidative stress, which arrests proliferation and restores normal acinar morphology. In hormone-negative breast cancers lacking human epidermal growth factor receptor 2 (
HER2
) amplification, we find that RUNX1 down-regulation is strongly associated with up-regulation of FOXO1, which may be required to support growth of RUNX1-negative tumors. The coordinate function of these two tumor suppressors may provide a failsafe mechanism that inhibits cancer progression.
CD4
+
CD25
+
Foxp3
+
regulatory T cell formation requires more specific recognition of a self-peptide than thymocyte deletion
Authors: Cozzo Picca Cristina , Simons Donald M. , Oh Soyoung , Aitken Malinda , Perng Olivia A. , Mergenthaler Christina , Kropf Elizabeth , Erikson Jan , Caton Andrew J.
Published: August 2011

CD4
+
CD25
+
Foxp3
+
regulatory T (Treg) cells are generated during thymocyte development and play a crucial role in preventing the immune system from attacking the body's cells and tissues. However, how the formation of these cells is directed by T-cell receptor (TCR) recognition of self-peptide:major histocompatibility complex (MHC) ligands remains poorly understood. We show that an agonist self-peptide with which a TCR is strongly reactive can induce a combination of thymocyte deletion and CD4
+
CD25
+
Foxp3
+
Treg cell formation in vivo. A weakly cross-reactive partial agonist self-peptide could similarly induce thymocyte deletion, but failed to induce Treg cell formation. These studies indicate that CD4
+
CD25
+
Foxp3
+
Treg cell formation can require highly stringent recognition of an agonist self-peptide by developing thymocytes. They also refine the “avidity” model of thymocyte selection by demonstrating that the quality of the signal mediated by agonist self-peptides, rather than the overall intensity of TCR signaling, can be a critical factor in directing autoreactive thymocytes to undergo CD4
+
CD25
+
Foxp3
+
Treg cell formation and/or deletion during their development.
Basic leucine zipper transcription factor, ATF-like (BATF) regulates epigenetically and energetically effector CD8 T-cell differentiation via Sirt1 expression
Authors: Kuroda Shoko , Yamazaki Maya , Abe Manabu , Sakimura Kenji , Takayanagi Hiroshi , Iwai Yoshiko
Published: August 2011

CD8 T cells play a critical role in protection against viral infections. During effector differentiation, CD8 T cells dramatically change chromatin structure and cellular metabolism, but how energy production increases in response to these epigenetic changes is unknown. We found that loss of basic leucine zipper transcription factor, ATF-like (BATF) inhibited effector CD8 T-cell differentiation. At the late effector stage, BATF was induced by IL-12 and required for IL-12–mediated histone acetylation and survival of effector T cells. BATF, together with c-Jun, transcriptionally inhibited expression of the nicotinamide adenine dinucleotide (NAD
+
)-dependent deacetylase Sirt1, resulting in increased histone acetylation of the T-bet locus and increased cellular NAD
+
, which increased ATP production. In turn, high levels of T-bet expression and ATP production promoted effector differentiation and cell survival. These results suggest that BATF promotes effector CD8 T-cell differentiation by regulating both epigenetic remodeling and energy metabolism through Sirt1 expression.
Topology of human apolipoprotein E3 uniquely regulates its diverse biological functions
Authors: Chen Jianglei , Li Qianqian , Wang Jianjun
Published: August 2011

Human apolipoprotein E (apoE) is one of the major determinants in lipid transport, playing a critical role in atherosclerosis and other diseases. Binding to lipid and heparan sulfate proteoglycans (HSPG) induces apoE to adopt active conformations for binding to low-density lipoprotein receptor (LDLR) family. ApoE also interacts with beta amyloid peptide, manifests critical isoform-specific effects on Alzheimer’s disease. Despite the importance of apoE in these major human diseases, the fundamental questions of how apoE adjusts its structure upon binding to regulate its diverse functions remain unsolved. We report the NMR structure of apoE3, displaying a unique topology of three structural domains. The C-terminal domain presents a large exposed hydrophobic surface that likely initiates interactions with lipids, HSPG, and beta amyloid peptides. The unique topology precisely regulates apoE tertiary structure to permit only one possible conformational adaptation upon binding and provides a double security in preventing lipid-free and partially-lipidated apoE from premature binding to apoE receptors during receptor biogenesis. This topology further ensures the optimal receptor-binding activity by the fully lipidated apoE during lipoprotein transport in circulation and in the brain. These findings provide a structural framework for understanding the structural basis of the diverse functions of this important protein in human diseases.
Control of body size by oxygen supply reveals size-dependent and size-independent mechanisms of molting and metamorphosis
Authors: Callier Viviane , Nijhout H. Frederik
Published: August 2011

Body size profoundly affects many aspects of animal biology, including metamorphosis, allometry, size-dependent alternative pathways of gene expression, and the social and ecological roles of individuals. However, regulation of body size is one of the fundamental unsolved problems in developmental biology. The control of body size requires a mechanism that assesses size and stops growth within a characteristic range of sizes. Under normal growth conditions in
Manduca sexta
, the endocrine cascade that causes the brain to initiate metamorphosis starts when the larva reaches a critical weight. Metamorphosis is initiated by a size-sensing mechanism, but the nature of this mechanism has remained elusive. Here we show that this size-sensing mechanism depends on the limited ability of a fixed tracheal system to sustain the oxygen supply to a growing individual. As body mass increases, the demand for oxygen also increases, but the fixed tracheal system does not allow a corresponding increase in oxygen supply. We show that interinstar molting has the same size-related oxygen-dependent mechanism of regulation as metamorphosis. We show that low oxygen tension induces molting at smaller body size, consistent with the hypothesis that under normal growth conditions, body size is regulated by a mechanism that senses oxygen limitation. We also found that under poor growth conditions, larvae may never attain the critical weight but eventually molt regardless. We show that under these conditions, larvae do not use the critical weight mechanism, but instead use a size-independent mechanism that is independent of the brain.
Subcutaneous administration of leptin normalizes fasting plasma glucose in obese type 2 diabetic UCD-T2DM rats
Authors: Cummings Bethany P. , Bettaieb Ahmed , Graham James L. , Stanhope Kimber L. , Dill Riva , Morton Gregory J. , Haj Fawaz G. , Havel Peter J.
Published: August 2011

Leptin has been shown to reduce hyperglycemia in rodent models of type 1 diabetes. We investigated the effects of leptin administration in University of California, Davis, type 2 diabetes mellitus (UCD-T2DM) rats, which develop adult-onset polygenic obesity and type 2 diabetes. Animals that had been diabetic for 2 mo were treated with s.c. injections of saline (control) or murine leptin (0.5 mg/kg) twice daily for 1 mo. Control rats were pair-fed to leptin-treated animals. Treatment with leptin normalized fasting plasma glucose and was accompanied by lowered HbA1c, plasma glucagon, and triglyceride concentrations and expression of hepatic gluconeogenic enzymes compared with vehicle (
P
< 0.05), independent of any effects on body weight and food intake. In addition, leptin-treated animals exhibited marked improvement of insulin sensitivity and glucose homeostasis compared with controls, whereas pancreatic insulin content was 50% higher in leptin-treated animals (
P
< 0.05). These effects coincided with activation of leptin and insulin signaling pathways and down-regulation of the PKR-like endoplasmic reticulum (ER) kinase/eukaryotic translation inhibition factor 2α (PERK-eIF2α) arm of ER stress in liver, skeletal muscle, and adipose tissue as well as increased pro-opiomelanocortin and decreased agouti-related peptide in the hypothalamus. In contrast, several markers of inflammation/immune function were elevated with leptin treatment in the same tissues (
P
< 0.05), suggesting that the leptin-mediated increase of insulin sensitivity was not attributable to decreased inflammation. Thus, leptin administration improves insulin sensitivity and normalizes fasting plasma glucose in diabetic UCD-T2DM rats, independent of energy intake, via peripheral and possibly centrally mediated actions, in part by decreasing circulating glucagon and ER stress.