33 research outputs found
Canopy Management to Improve Grape Yield and Wine Quality - Principles and Practices
This paper reviews the subject of canopy management with an attempt to develop principles. These principles provide guidelines for canopy surface area amount; spacing between canopies; within canopy shade, especially for the fruiting/ renewal zone; balance between fruit and shoot growth; and uniformity of location of fruit/renewal zones, shoot tips and cane bases. Field techniques of point quadrat analysis and canopy scoring are introduced as an aid to defining problem canopies. These techniques are cheap, quick and effective. A set of twenty-one numeric indices and descriptors to assess winegrape canopies is then presented as a winegrape canopy ideotype, which can be further used as management guidelines. Recent publications are reviewed from various aspects of canopy management. These include vigour control, shoot trimming, leaf removal in the fruit zone and training system responses. The paper concludes with presentation of the authors' unpublished data on the effects of canopy microclimate on yield and wine quality. The trial was conducted with the cultivar Cabernet franc on a deep, fertile soil in a cool, high rainfall region. Canopy division using the Ruakura Twin Two Tier doubled yield compared to dense, vertical shoot positioned canopies which are common in New Zealand. Shade caused reduction in all yield components, and also delayed fruit ripening and reduced wine quality. Similar results were obtained by comparing fruit production at different heights with the Te Kauwhata Three Tier trellis system, where lower tiers were shaded at the canopy exterior. The results confirm that grape yield and wine quaiity can be simultaneously increased by improved canopy management of shaded vineyards
The Hubble constant and dark energy from cosmological distance measures
We study how the determination of the Hubble constant from cosmological
distance measures is affected by models of dark energy and vice versa. For this
purpose, constraints on the Hubble constant and dark energy are investigated
using the cosmological observations of cosmic microwave background, baryon
acoustic oscillations and type Ia suprenovae. When one investigates dark
energy, the Hubble constant is often a nuisance parameter, thus it is usually
marginalized over. On the other hand, when one focuses on the Hubble constant,
simple dark energy models such as a cosmological constant and a constant
equation of state are usually assumed. Since we do not know the nature of dark
energy yet, it is interesting to investigate the Hubble constant assuming some
types of dark energy and see to what extent the constraint on the Hubble
constant is affected by the assumption concerning dark energy. We show that the
constraint on the Hubble constant is not affected much by the assumption for
dark energy. We furthermore show that this holds true even if we remove the
assumption that the universe is flat. We also discuss how the prior on the
Hubble constant affects the constraints on dark energy and/or the curvature of
the universe.Comment: 45 pages, 15 figure
Political leaders' identity leadership and civic citizenship behavior:The mediating role of trust in fellow citizens and the moderating role of economic inequality
Identity leadership captures leaders efforts to create and promote a sense of shared group membership (i.e., a sense of “we” and of “us”) among followers. The present research report tests this claim by drawing on data from 26 countries that are part of the Global Identity Leadership Development (GILD) project to examine the relationship between political leaders' identity leadership and civic citizenship behavior (N = 6787). It also examines the contributions of trust and economic inequality to this relationship. Political leaders' identity leadership (PLIL) was positively associated with respondents' people-oriented civic citizenship behaviors (CCB-P) in 20 of 26 countries and civic citizenship behaviors aimed at one's country (CCB-C) in 23 of 26 countries. Mediational analyses also confirmed the indirect effects of PLIL via trust in fellow citizens on both CCB-P (in 25 out of 26 countries) and CCB-C (in all 26 countries). Economic inequality moderated these effects such that the main and indirect effects of trust in one's fellow citizens on CCB-C were stronger in countries with higher economic inequality. This interaction effect was not observed for CCB-P. The study highlights the importance of identity leadership and trust in fellow citizens in promoting civic citizenship behavior, especially in the context of economic inequality.</p
Political leaders' identity leadership and civic citizenship behavior:The mediating role of trust in fellow citizens and the moderating role of economic inequality
Identity leadership captures leaders efforts to create and promote a sense of shared group membership (i.e., a sense of “we” and of “us”) among followers. The present research report tests this claim by drawing on data from 26 countries that are part of the Global Identity Leadership Development (GILD) project to examine the relationship between political leaders' identity leadership and civic citizenship behavior (N = 6787). It also examines the contributions of trust and economic inequality to this relationship. Political leaders' identity leadership (PLIL) was positively associated with respondents' people-oriented civic citizenship behaviors (CCB-P) in 20 of 26 countries and civic citizenship behaviors aimed at one's country (CCB-C) in 23 of 26 countries. Mediational analyses also confirmed the indirect effects of PLIL via trust in fellow citizens on both CCB-P (in 25 out of 26 countries) and CCB-C (in all 26 countries). Economic inequality moderated these effects such that the main and indirect effects of trust in one's fellow citizens on CCB-C were stronger in countries with higher economic inequality. This interaction effect was not observed for CCB-P. The study highlights the importance of identity leadership and trust in fellow citizens in promoting civic citizenship behavior, especially in the context of economic inequality.</p
Species-specific responses of Late Quaternary megafauna to climate and humans
Despite decades of research, the roles of climate and humans in driving the dramatic extinctions of large-bodied mammals during the Late Quaternary remain contentious. We use ancient DNA, species distribution models and the human fossil record to elucidate how climate and humans shaped the demographic history of woolly rhinoceros, woolly mammoth, wild horse, reindeer, bison and musk ox. We show that climate has been a major driver of population change over the past 50,000 years. However, each species responds differently to the effects of climatic shifts, habitat redistribution and human encroachment. Although climate change alone can explain the extinction of some species, such as Eurasian musk ox and woolly rhinoceros, a combination of climatic and anthropogenic effects appears to be responsible for the extinction of others, including Eurasian steppe bison and wild horse. We find no genetic signature or any distinctive range dynamics distinguishing extinct from surviving species, underscoring the challenges associated with predicting future responses of extant mammals to climate and human-mediated habitat change.This paper is in the memory of our friend and colleague Dr. Andrei Sher, who was a major contributor of this study. Dr Sher died unexpectedly, but his major contributions to the field of Quaternary science will be remembered and appreciated for many years to come. We are grateful to Dr. Adrian Lister and Dr. Tony Stuart for guides and discussions. Thanks to Tina B. Brandt, Dr. Bryan Hockett and Alice Telka for laboratory help and samples and to L. Malik R. Thrane for his work on the megafauna locality database. Data taken from the Stage 3 project was partly funded by Grant #F/757/A from the Leverhulme Trust, together with a grant from the McDonald Grants and Awards Fund. We acknowledge the Danish National Research Foundation, the Lundbeck Foundation, the Danish Council for Independent Research and the US National Science Foundation for financial suppor
The genetic architecture of the human cerebral cortex
The cerebral cortex underlies our complex cognitive capabilities, yet little is known about the specific genetic loci that influence human cortical structure. To identify genetic variants that affect cortical structure, we conducted a genome-wide association meta-analysis of brain magnetic resonance imaging data from 51,665 individuals. We analyzed the surface area and average thickness of the whole cortex and 34 regions with known functional specializations. We identified 199 significant loci and found significant enrichment for loci influencing total surface area within regulatory elements that are active during prenatal cortical development, supporting the radial unit hypothesis. Loci that affect regional surface area cluster near genes in Wnt signaling pathways, which influence progenitor expansion and areal identity. Variation in cortical structure is genetically correlated with cognitive function, Parkinson's disease, insomnia, depression, neuroticism, and attention deficit hyperactivity disorder
Finishing the euchromatic sequence of the human genome
The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead
Conversion Discriminative Analysis on Mild Cognitive Impairment Using Multiple Cortical Features from MR Images
Neuroimaging measurements derived from magnetic resonance imaging provide important information required for detecting changes related to the progression of mild cognitive impairment (MCI). Cortical features and changes play a crucial role in revealing unique anatomical patterns of brain regions, and further differentiate MCI patients from normal states. Four cortical features, namely, gray matter volume, cortical thickness, surface area, and mean curvature, were explored for discriminative analysis among three groups including the stable MCI (sMCI), the converted MCI (cMCI), and the normal control (NC) groups. In this study, 158 subjects (72 NC, 46 sMCI, and 40 cMCI) were selected from the Alzheimer's Disease Neuroimaging Initiative. A sparse-constrained regression model based on the l2-1-norm was introduced to reduce the feature dimensionality and retrieve essential features for the discrimination of the three groups by using a support vector machine (SVM). An optimized strategy of feature addition based on the weight of each feature was adopted for the SVM classifier in order to achieve the best classification performance. The baseline cortical features combined with the longitudinal measurements for 2 years of follow-up data yielded prominent classification results. In particular, the cortical thickness produced a classification with 98.84% accuracy, 97.5% sensitivity, and 100% specificity for the sMCI–cMCI comparison; 92.37% accuracy, 84.78% sensitivity, and 97.22% specificity for the cMCI–NC comparison; and 93.75% accuracy, 92.5% sensitivity, and 94.44% specificity for the sMCI–NC comparison. The best performances obtained by the SVM classifier using the essential features were 5–40% more than those using all of the retained features. The feasibility of the cortical features for the recognition of anatomical patterns was certified; thus, the proposed method has the potential to improve the clinical diagnosis of sub-types of MCI and predict the risk of its conversion to Alzheimer's disease
Quantitative 18F-AV1451 Brain Tau PET Imaging in Cognitively Normal Older Adults, Mild Cognitive Impairment, and Alzheimer's Disease Patients
Recent developments of tau Positron Emission Tomography (PET) allows assessment of regional neurofibrillary tangles (NFTs) deposition in human brain. Among the tau PET molecular probes, 18F-AV1451 is characterized by high selectivity for pathologic tau aggregates over amyloid plaques, limited non-specific binding in white and gray matter, and confined off-target binding. The objectives of the study are (1) to quantitatively characterize regional brain tau deposition measured by 18F-AV1451 PET in cognitively normal older adults (CN), mild cognitive impairment (MCI), and AD participants; (2) to evaluate the correlations between cerebrospinal fluid (CSF) biomarkers or Mini-Mental State Examination (MMSE) and 18F-AV1451 PET standardized uptake value ratio (SUVR); and (3) to evaluate the partial volume effects on 18F-AV1451 brain uptake.Methods: The study included total 115 participants (CN = 49, MCI = 58, and AD = 8) from the Alzheimer's Disease Neuroimaging Initiative (ADNI). Preprocessed 18F-AV1451 PET images, structural MRIs, and demographic and clinical assessments were downloaded from the ADNI database. A reblurred Van Cittertiteration method was used for voxelwise partial volume correction (PVC) on PET images. Structural MRIs were used for PET spatial normalization and region of interest (ROI) definition in standard space. The parametric images of 18F-AV1451 SUVR relative to cerebellum were calculated. The ROI SUVR measurements from PVC and non-PVC SUVR images were compared. The correlation between ROI 18F-AV1451 SUVR and the measurements of MMSE, CSF total tau (t-tau), and phosphorylated tau (p-tau) were also assessed.Results:18F-AV1451 prominently specific binding was found in the amygdala, entorhinal cortex, parahippocampus, fusiform, posterior cingulate, temporal, parietal, and frontal brain regions. Most regional SUVRs showed significantly higher uptake of 18F-AV1451 in AD than MCI and CN participants. SUVRs of small regions like amygdala, entorhinal cortex and parahippocampus were statistically improved by PVC in all groups (p < 0.01). Although there was an increasing tendency of 18F-AV-1451 SUVRs in MCI group compared with CN group, no significant difference of 18F-AV1451 deposition was found between CN and MCI brains with or without PVC (p > 0.05). Declined MMSE score was observed with increasing 18F-AV1451 binding in amygdala, entorhinal cortex, parahippocampus, and fusiform. CSF p-tau was positively correlated with 18F-AV1451 deposition. PVC improved the results of 18F-AV-1451 tau deposition and correlation studies in small brain regions.Conclusion: The typical deposition of 18F-AV1451 tau PET imaging in AD brain was found in amygdala, entorhinal cortex, fusiform and parahippocampus, and these regions were strongly associated with cognitive impairment and CSF biomarkers. Although more deposition was observed in MCI group, the 18F-AV-1451 PET imaging could not differentiate the MCI patients from CN population. More tau deposition related to decreased MMSE score and increased level of CSF p-tau, especially in ROIs of amygdala, entorhinal cortex and parahippocampus. PVC did improve the results of tau deposition and correlation studies in small brain regions and suggest to be routinely used in 18F-AV1451 tau PET quantification