Theoretical measures of relative performance of classifiers for high dimensional data with small sample sizes

We suggest a technique, related to the concept of 'detection boundary' that was developed by Ingster and by Donoho and Jin, for comparing the theoretical performance of classifiers constructed from small training samples of very large vectors. The resulting 'classification boundaries' are obtained for a variety of distance-based methods, including the support vector machine, distance-weighted discrimination and kth-nearest-neighbour classifiers, for thresholded forms of those methods, and for techniques based on Donoho and Jin's higher criticism approach to signal detection. Assessed in these terms, standard distance-based methods are shown to be capable only of detecting differences between populations when those differences can be estimated consistently. However, the thresholded forms of distance-based classifiers can do better, and in particular can correctly classify data even when differences between distributions are only detectable, not estimable. Other methods, including higher criticism classifiers, can on occasion perform better still, but they tend to be more limited in scope, requiring substantially more information about the marginal distributions. Moreover, as tail weight becomes heavier the classification boundaries of methods designed for particular distribution types can converge to, and achieve, the boundary for thresholded nearest neighbour approaches. For example, although higher criticism has a lower classification boundary, and in this sense performs better, in the case of normal data, the boundaries are identical for exponentially distributed data when both sample sizes equal 1

Comparison of Organic and Integrated Nutrient Management Strategies for Reducing Soil N\u3csub\u3e2\u3c/sub\u3eO Emissions

To prevent nutrient limitations to crop growth, nitrogen is often applied in agricultural systems in the form of organic inputs (e.g., crop residues, manure, compost, etc.) or inorganic fertilizer. Inorganic nitrogen fertilizer has large environmental and economic costs, particularly for low-input smallholder farming systems. The concept of combining organic, inorganic, and biological nutrient sources through Integrated Nutrient Management (INM) is increasingly promoted as a means of improving nutrient use efficiency by matching soil nutrient availability with crop demand. While the majority of previous research on INM has focused on soil quality and yield, potential climate change impacts have rarely been assessed. In particular, it remains unclear whether INM increases or decreases soil nitrous oxide (N2O) emissions compared to organic nitrogen inputs, which may represent an overlooked environmental tradeoff. The objectives of this review were to (i) summarize the mechanisms influencing N2O emissions in response to organic and inorganic nitrogen (N) fertilizer sources, (ii) synthesize findings from the limited number of field experiments that have directly compared N2O emissions for organic N inputs vs. INM treatments, (iii) develop a hypothesis for conditions under which INM reduces N2O emissions and (iv) identify key knowledge gaps to address in future research. In general, INM treatments having low carbon to nitrogen ratio C:N (2O emissions

Thiosemicarbazone organocatalysis:Tetrahydropyranylation and 2-deoxygalactosylation reactions and kinetics-based mechanistic investigation

Thiosemicarbazones are introduced as a new class of highly tunable and efficient organocatalysts. We showcase this by studies of the tetrahydropyranylation reaction, where insights to the mechanism was achieved by a double Hammett analysis of both the substrate and the catalyst.</p

Sn(IV)-corroles reversibly bind carboxylates in the axial position

We present the synthesis of Sn(IV)-corrole complexes that bind to carboxylate moieties reversibly, via axial ligation. The systems have been predominantly characterized using H-1 NMR spectroscopy, X-ray crystallography, and MALDI mass spectrometry. The dynamic nature of the Sn(IV)-O2CR bond has been studied in solution using 2D-NMR spectroscopy

Social Anxiety and Empathy:A Systematic Review and Meta-analysis

OBJECTIVE: This systematic review and meta-analysis aimed to clarify the association between social anxiety and affective (AE) and cognitive empathy (CE). METHODS: 1442 studies from PsycINFO, Medline, and EMBASE (inception-January 2020) were systematically reviewed. Included studies (N = 48) either predicted variance in empathy using social anxiety scores or compared empathy scores between socially anxious individuals and a control group. RESULTS: Social anxiety and AE were statistically significantly positively associated, k = 14, r = .103 (95%CI [.003, .203]), z = 2.03, p = .043. Sex (QM (2) = 18.79, p <  .0001), and type of measures (QM (1 = 7.34, p = .007) moderated the association. Correlations were significant for male samples (rmale = .316, (95%CI [.200, .432])) and studies using self-report measures (rself-report = .162 (95%CI [.070, .254])). Overall, social anxiety and CE were not significantly associated, k = 52, r =-.021 (95%CI [-.075, .034]), z= -0.74, p = .459. Sample type moderated the association (QM (1) = 5.03, p < .0001). For clinical samples the association was negative (rclinical= -.112, (95%CI [-.201, -.017]). CONCLUSION: There was evidence for a positive association between social anxiety and AE, but future studies are needed to verify the moderating roles of sex and type of measure. Besides, low CE might only hold for patients with SAD

Simulated dataset of corn response to nitrogen over thousands of fields and multiple years in Illinois

Nitrogen (N) fertilizer recommendations for corn (Zea mays L.) in the US Midwest have been a puzzle for several decades, without agreement among stakeholders for which methodology is the best to balance environmental and economic outcomes. Part of the reason is the lack of long-term data of crop responses to N over multiple fields since trial data is often limited in the number of soils and years it can explore. To overcome this limitation, we designed an analytical platform based on crop simulations run over millions of farming scenarios over extensive geographies. The database was calibrated and validated using data from more than four hundred trials in the region. This dataset can have an important role for research and education in N management, machine leaching, and environmental policy analysis. The calibration and validation procedure provides a framework for future gridded crop model studies. We describe dataset characteristics and provide thorough descriptions of the model setup

Estabelecimento de normas DRIS para o cupuaçueiro na região amazônica.

A avaliação do estado nutricional de um pomar ou lavoura depende da definição de valores de referência que sejam adequados para refletir as condições de crescimento das plantas. Neste sentido, o objetivo deste trabalho foi determinar normas DRIS para cupuaçueiro cultivado na Amazônia, testando em populações com diferentes idades. Amostras foliares de cupuaçu foram coletadas de pomares comerciais, cuja idade das plantas variou de 5 a 18 anos, cultivadas sob monocultivo ou sistemas agroflorestais (SAF's), obtendo-se para cada relação nutricional entre os nutrientes N, P, K, Ca, Mg, Zn, Fe, Mn e Cu as normas DRIS, as quais foram obtidas para o conjunto da população monitorada e para subpopulações específicas. Os diferentes grupos de normas não diferem entre si, possibilitando a obtenção de normas DRIS que possam representar um grande número de condições de produção

The blue vibronically resolved electroluminescence of azatrioxa[8]circulene

Organic Light Emitting Dioides (OLED)devices were fabricated with blue emission based on azatrioxa[8]circulene and 4,4-N,N'-Dicarbazolyl-1,1'-biphenyl (CBP) with maximum brightness of 840 kd/m(2) at 12 V and the starting voltage of 3.5 V. The vibronic emission spectrum was analyzed by the promotive modes calculation method. The electroluminescence of fabricated OLED device is caused by the 0-0 electronic transition and single excitations of 1473 cm(-1) and 1673 cm(-1) modes and combinations thereof.Peer reviewe

Impairment of organ-specific T cell negative selection by diabetes susceptibility genes: genomic analysis by mRNA profiling

BACKGROUND T cells in the thymus undergo opposing positive and negative selection processes so that the only T cells entering circulation are those bearing a T cell receptor (TCR) with a low affinity for self. The mechanism differentiating negative from positive selection is poorly understood, despite the fact that inherited defects in negative selection underlie organ-specific autoimmune disease in AIRE-deficient people and the non-obese diabetic (NOD) mouse strain RESULTS Here we use homogeneous populations of T cells undergoing either positive or negative selection in vivo together with genome-wide transcription profiling on microarrays to identify the gene expression differences underlying negative selection to an Aire-dependent organ-specific antigen, including the upregulation of a genomic cluster in the cytogenetic band 2F. Analysis of defective negative selection in the autoimmune-prone NOD strain demonstrates a global impairment in the induction of the negative selection response gene set, but little difference in positive selection response genes. Combining expression differences with genetic linkage data, we identify differentially expressed candidate genes, including Bim, Bnip3, Smox, Pdrg1, Id1, Pdcd1, Ly6c, Pdia3, Trim30 and Trim12. CONCLUSION The data provide a molecular map of the negative selection response in vivo and, by analysis of deviations from this pathway in the autoimmune susceptible NOD strain, suggest that susceptibility arises from small expression differences in genes acting at multiple points in the pathway between the TCR and cell death.This work was supported by grants from the NHMRC and the Juvenile Diabetes Research Foundation