Stellar color regression: a spectroscopy based method for color calibration to a few mmag accuracy and the recalibration of Stripe 82

In this paper, we propose a spectroscopy based Stellar Color Regression (SCR) method to perform accurate color calibration for modern imaging surveys, taking advantage of millions of stellar spectra now available. The method is straightforward, insensitive to systematic errors in the spectroscopically determined stellar atmospheric parameters, applicable to regions that are effectively covered by spectroscopic surveys, and capable of delivering an accuracy of a few millimagnitudes for color calibration. As an illustration, we have applied the method to the SDSS Stripe 82 data (Ivezic et al; I07 hereafter). With a total number of 23,759 spectroscopically targeted stars, we have mapped out the small but strongly correlated color zero point errors present in the photometric catalog of Stripe 82, and improve the color calibration by a factor of 2 -- 3. Our study also reveals some small but significant magnitude dependence errors in z-band for some CCDs. Such errors are likely to be present in all the SDSS photometric data. Our results are compared with those from a completely independent test based on the intrinsic colors of red galaxies presented by I07. The comparison as well as other tests shows that the SCR method has achieved a color calibration internally consistent at a level of about 5 mmag in u-g, 3 mmag in g-r, and 2 mmag in r-i and i-z, respectively. Given the power of the SCR method, we discuss briefly the potential benefits by applying the method to existing, on-going, and up-coming imaging surveys.Comment: 17 pages, 14 figures, 3 tables, ApJ in pres

Automated identification of 2612 late-k and M dwarfs in the LAMOST commissioining data using the classification template fits

We develop a template-fit method to automatically identify and classify late-type K and M dwarfs in spectra from the LAMOST. A search of the commissioning data, acquired in 2009-2010, yields the identification of 2612 late-K and M dwarfs. The template fit method also provides spectral classification to half a subtype, classifies the stars along the dwarf-subdwarf metallicity sequence, and provides improved metallicity/gravity information on a finer scale. The automated search and classification is performed using a set of cool star templates assembled from the Sloan Digital Sky Survey spectroscopic database. We show that the stars can be efficiently classified despite shortcomings in the LAMOST commissioning data which include bright sky lines in the red. In particular we find that the absolute and relative strengths of the critical TiO and CaH molecular bands around 7000A are cleanly measured, which provides accurate spectral typing from late-K to mid-M, and makes it possible to estimate metallicities in a way that is more efficient and reliable than with the use of spectral indices or spectral-index based parameters such as zeta. Most of the cool dwarfs observed by LAMOST are found to be metal-rich dwarfs. We use a calibration of spectral type to absolute magnitude and estimate spectroscopic distances for all the stars; we also recover proper motions from the SUPERBLINK and PPMXL catalogs. Our analysis of the estimated transverse motions suggests a mean velocity and standard deviation for the UVW components of velocity to be: U=-9.8 km/s; V=-22.8 km/s; W=-7.9 km/s. The resulting values are general agreement with previous reported results, which yields confidence in our spectral classification and spectroscopic distance estimates, and illustrates the potential for using LAMOST spectra of K and M dwarfs for investigating the chemo-kinematics of the local Galactic disk and halo.Comment: 18 pages,16 figures,accepted for publication A

Prediction of xylanase optimal temperature by support vector regression

Background: Support vector machine (SVM), a novel powerful machine learning technology, was used to develop the non-linear quantitative structure-property relationship (QSPR) model of the G/11 xylanase based on the amino acid composition. The uniform design (UD) method was applied to optimize the running parameters of SVM for the first time. Results: Results showed that the predicted optimum temperature of leave-one-out (LOO) cross-validation fitted the experimental optimum temperature very well, when the running parameter C, \u190, and \u3b3 was 50, 0.001 and 1.5, respectively. The average root-mean-square errors (RMSE) of the LOO cross-validation were 9.53\ubaC, while the RMSE of the back propagation neural network (BPNN), was 11.55\ubaC. The predictive ability of SVM is a minor improvement over BPNN, but it is superior to the reported method based on stepwise regression. Two experimental examples proved the validation of the model for predicting the optimal temperature of xylanase. Conclusion: The results indicated that UD might be an effective method to optimize the parameters of SVM, which could be used as an alternative powerful modeling tool for QSPR studies of xylanase

Solid fat content and bakery characteristics of interesterified beef tallow-palm mid fraction based margarines

Palm mid fraction (PMF) was interesterified with edible beef tallow (BT) catalyzed using sodium methoxide to investigate the effects on the solid fat content (SFC) of these palmitic rich plastic fats. Interesterified blends crystallize more slowly than BT. Conversely, the crystallization rates of PMF-BT-based interesterification (IE) products were compared with the starting mixture and IE products prepared with non-PMF triglycerides. The SFC PMF-based IE products increased significantly at temperatures between 25 and 40 °C. The SFC profiles became smoother and the products had potential to serve as base oils for preparing specialty fats with a wider range of plasticity. Further exploration of triacylglycerol (TAG) compositional changes revealed that PMF interesterified products had greater saturated/saturated/saturated (S/S/S)-type TAGs compared with soybean oil interesterified products. Moreover, in subsequent evaluations of BT-PMF-based IE fats as a margarine replacement effects in a baked cake model system showed that the material was a suitable functional oil base with acceptable aeration properties and plasticity during baking. Therefore, it is a potential alternative to IE-BT based and traditional IE-BT-palm oil based margarines. The physical-characteristics of bakery products prepared with this fat exhibited improved cake volume with fine structure and clear lifting properties, which affirmed the potential for its application in bakery fats

Challenges and Strategies for High‐Energy Aqueous Electrolyte Rechargeable Batteries

Aqueous rechargeable batteries are becoming increasingly important to the development of renewable energy sources, because they promise to meet cost‐efficiency, energy and power demands for stationary applications. Over the past decade, efforts have been devoted to the improvement of electrode materials and their use in combination with highly concentrated aqueous electrolytes. Here the latest ground‐breaking advances in using such electrolytes to construct aqueous battery systems efficiently storing electrical energy, i.e., offering improved energy density, cyclability and safety, are highlighted. This Review aims to timely provide a summary of the strategies proposed so far to overcome the still existing hurdles limiting the present aqueous batteries technologies employing concentrated electrolytes. Emphasis is placed on aqueous batteries for lithium and post‐lithium chemistries, with potentially improved energy density, resulting from the unique advantages of concentrated electrolytes

Regulation of the stability and transcriptional activity of NFATc4 by ubiquitination

AbstractNuclear factor of activated T cells (NFATc4) has been implicated as a critical regulator of the cardiac development and hypertrophy. However, the mechanisms for regulating NFATc4 stability and transactivation remain unclear. We showed that NFATc4 protein was predominantly ubiquitinated through the formation of Lysine 48-linked polyubiquitin chains, and this modification decreased NFATc4 protein levels and its transcriptional activity. Furthermore, activation of GSK3β markedly enhanced NFATc4 ubiquitination and decreased its transactivation, whereas inhibition of GSK3β had opposite effects. Importantly, ubiquitination and phosphorylation induced by GSK3β repressed NFATc4-dependent cardiac-specific gene expression. These results demonstrate that the ubiquitin–proteasome system plays an important role in regulating NFATc4 stability and transactivation.Structured summaryMINT-6798349:NFATc4 (uniprotkb:Q14934) physically interacts (MI:0218) with Ubiquitin (uniprotkb:P62988) by anti bait coimmunoprecipitation (MI:0006)MINT-6798334:NFATc4 (uniprotkb:Q14934) physically interacts (MI:0218) with Ubiquitin (uniprotkb:P62988) by anti tag coimmunoprecipitation (MI:0007)MINT-6798321:Ubiquitin (uniprotkb:P62988) physically interacts (MI:0218) with NFATc4 (uniprotkb:Q14934) by pull down (MI:0096

Residents’ participation in energy performance certification for collective action on climate change: the case of EnerGuide

IntroductionAlthough governments have launched energy performance certification (EPC) programs to increase residential energy efficiency, residents’ perception and acceptance of these programs have been little studied. This study contextualizes residents’ intentions to participate in EPC programs in terms of their attributions to and attitudes toward climate change to find mediating factors and effects to help trigger collective action to reduce residential sector energy demand.MethodsThis study employed a partial least squares structural equation modeling approach to empirically analyze a survey conducted on 400 residents of Edmonton, Canada, who participated in the Canadian energy efficiency rating and labeling program, EnerGuide.Results and DiscussionUsing EnerGuide, a Canadian energy efficiency rating and labeling program, as an example, this study establishes a framework to explain that local residents’ internal and external attributions to climate change elicit positive attitudes (need to take action), increasing their recognition of energy efficiency program benefits, which further promotes their EnerGuide program acceptance and participation intentions. This study also reveals the mediating effects between variables. Residents’ attitudes toward climate change mediate the relationship between internal/external attributions and EnerGuide program acceptance, and they indirectly impact residents’ program acceptance and participation intentions, with this effect moderated by energy efficiency program benefits. Residents’ program acceptance also mediates the relationship between climate change attitudes/energy efficiency program benefits and the intention outcome.ImplicationThe study provides an example of the use of climate change discourse to motivate residents’ energy efficiency program participation

Layered Oxide Material as a Highly Stable Na‐ion Source and Sink for Investigation of Sodium‐ion Battery Materials

Investigating Na-ion battery (SIB) materials is complicated by the absence of a well-performing (reference) electrode material since sodium metal cannot be considered as a quasi-reference electrode. Taking advantage of the activity of both Ni and Mn, herein, the P2-type and Mn-rich Na$_{0.6}$Ni$_{0.22}$Al$_{0.11}$Mn$_{0.66}$O$_2$ (NAM) material, known to be an excellent positive electrode, is investigated as a negative electrode. To prove NAM stability as both positive and negative electrode, symmetric cells have been assembled without pre-sodiation, which showed a reversible capacity of 73 mA h g$^{−1}$ and a remarkable capacity retention of 82.6 % after 500 cycles. The outstanding cycling performance is ascribed to the high stability of the active material at both the highest and lowest Na-ion storage plateaus and the rather limited electrolyte decomposition and solid-electrolyte-interphase (SEI) formation occurring. The long-term stability of NAM at both electrodes enables its use as a “reference” electrode for the investigation of other positive and negative electrode materials for SIBs, resembling the role played by lithium titanate (LTO) and lithium iron phosphate (LFP) in LIBs