239 research outputs found
A Carleman type theorem for proper holomorphic embeddings
In 1927, Carleman showed that a continuous, complex-valued function on the
real line can be approximated in the Whitney topology by an entire function
restricted to the real line. In this paper, we prove a similar result for
proper holomorphic embeddings. Namely, we show that a proper \cC^r embedding
of the real line into \C^n can be approximated in the strong \cC^r topology
by a proper holomorphic embedding of \C into \C^n
Toward a theory for diversity gradients: the abundance–adaptation hypothesis
The abundance–adaptation hypothesis argues that taxa with more individuals and faster generation times will have more evolutionary ‘experiments’ allowing expansion into, and diversification within, novel habitats. Thus, as older taxa have produced more individuals over time, and smaller taxa have higher population sizes and faster generation times, the Latitudinal Diversity Gradients (LDGs) of these clades should show shallower slopes. We describe the LDGs for archaea, bacteria, fungi, invertebrates and trees from six North American forests. For three focal groups – bacteria, ants, and trees – older taxa had shallower LDG slopes than the more recent, terminal taxa. Across 12 orders of magnitude of body mass, LDG slopes were steeper in larger taxa. The slopes of LDGs vary systematically with body size and clade age, underscoring the non-canonical nature of LDGs. The steepest LDG slopes were found for the largest organisms while the smallest, from bacteria to small litter-soil invertebrates, have shallower- to zero-slope LDGs. If tropical niche conservatism is the failure of clades to adapt to, and diversify in temperate habitats, then the steep LDGs of chordates and plants likely arise from the decreased ability of clades with large individuals to adapt to the multiple challenges of extra-tropical life
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A mathematical model of melt lake development on an ice shelf
The accumulation of surface meltwater on ice shelves can lead to the formation of melt lakes. Melt lakes have been implicated in ice shelf collapse; Antarctica's Larsen B Ice Shelf was observed to have a large amount of surface melt lakes present preceding its collapse in 2002. Such collapse can affect ocean circulation and temperature, cause habitat loss and contribute to sea level rise through the acceleration of tributary glaciers. We present a mathematical model of a surface melt lake on an idealised ice shelf. The model incorporates a calculation of the ice shelf surface energy balance, heat transfer through the firn, the production and percolation of meltwater into the firn, the formation of ice lenses and the development and refreezing of surface melt lakes.
The model is applied to the Larsen C Ice Shelf, where melt lakes have been observed. This region has warmed several times the global average over the last century and the Larsen C firn layer could become saturated with meltwater by the end of the century.
When forced with weather station data, our model produces surface melting, meltwater accumulation, and melt lake development consistent with observations. We examine the sensitivity of lake formation to uncertain parameters, and provide evidence of the importance of processes such as lateral meltwater transport.
We conclude that melt lakes impact surface melt and firn density and warrant inclusion in dynamic-thermodynamic models of ice shelf evolution within climate models, of which our model could form the basis for the thermodynamic component
An embedding of ℂ in ℂ 2 with hyperbolic complement
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46249/1/208_2005_Article_BF01445264.pd
Integral models of Hilbert modular varieties in the ramified case, deformations of modular Galois representations, and weight one forms
2002 Wild Blueberry Project Reports
The 2002 edition of the Wild Blueberry Project Reports was prepared for the Wild Blueberry Commission of Maine and the Wild Blueberry Advisory Committee by researchers at the University of Maine, Orono. Projects in this report include:
1. Factors Affecting Microbial and Pesticide Residue Levels on Wild Blueberries
2. Effect of Blueberry Products on Oxidation in Meat Based Food
3. Determination of Pesticide Residue Levels in Freshly Harvested and Processed Wild Blueberries
4. Detection of Infested Wild Blueberries using Near-Infrared Spectroscopy
5. Investigation Of The Mechanism By Which Blueberry Fractions Maintain Arterial Integrity
6. Antioxidant Assessment in the Elderly
7. Water Use of Wild Blueberries and the Impact of Plant Water Stress on Yield
8. Control Tactics for Wild blueberry Pest Insects
9. IPM Strategies
10. Pest Biology
11. Wild Blueberry Pollination Research
12. Survey and Determination of Effective Control of Stem Blight and Leaf Spot Diseases in Wild Blueberry Fields
13. Effect of Foliar-applied Iron Chelate Concentration on Leaf Iron Concentration, Wild Blueberry Growth and Yield
14. Effect of Boron Application Methods on Boron Uptake in Wild Blueberries
15. Effect of Foliar N spray on Leaf N Concentration, Growth and Yield of Wild Blueberries
16. Effect of Foliar Spray (4-13-15) on Leaf Nutrient Concentration, Growth and Yield of Wild Blueberries
17. Effect of Foliar Copper Application on Growth and Yield of Wild Blueberries
18. Effect of Foliar Copper and/or Iron Application on Growth and Yield of Wild Blueberries
19. Effect of Soil pH on Nutrient Uptake
20. Assessment of Hexazinone Alternatives for Weed Control in Wild Blueberries and Weed Control
21. Evaluation of Fall Applications of Sulfonylurea Herbicides for Bunchberry Control in Wild Blueberries
22. Evaluation and Demonstration of Techniques for Filling in Bare Spots in Wild Blueberry Fields
23. Blueberry Extension Education Program Base
24. 2002 Pesticide Groundwater Survey
25. Cultural Weed Management using sulfur to lower the p
2001 Wild Blueberry CSREES Project Reports
The 2001 edition of the Wild Blueberry CSREES Progress Reports was prepared for the Maine Wild Blueberry Commission and the University of Maine Wild Blueberry Advisory Committee by researchers at the University of Maine, Orono. Projects in this report include:
1. Effect of Wild Blueberry Products on Oxidation in Meat Based Food Systems
2. Factors Affecting the Microbial and Pesticide Residues Levels on Wild Blueberries
3. Determination of Pesticide Residue Levels in Fresh and Processed Wild Blueberries
4. Separation of Maggot-Infested Wild Blueberries in the IQF Processing Line
5. Water Use of Wild Blueberries and the Impact of Plant Water Stress on Yields
6. Survey of Stem Blight and Leaf Spot Diseases in Wild Blueberry Fields
7. IPM Strategies
8. Control Tactics for Wild Blueberry Pest Insects, 2001
9. Biology and Ecology of Blueberry Pest Insects
10. Diurnal Bee Activity and Measurement of Honeybee Field Strength
11. Effect of Foliar-applied Iron (Fe) Chelate Concentration on Leaf Iron Concentration, Wild Blueberry Growth and Yield
12. Effect of Boron Application Methods on Boron Uptake in Wild Blueberries
13. Effect of Foliar Iron and Copper Application on Growth and Yield of Wild Blueberries
14. Effect of Fertilizer Timing on Wild Blueberry Growth and Productivity
15. Effect of Foliar Copper Application on Growth and Yield of Wild Blueberries
16. Effect of Prune-year Applications of Nutri-Phitetm P or Nutri-Phitetm P+K on Growth and Yield of Wild Blueberry (Vaccinium angustifolium Ait.)
17. Effect of Soil pH on Nutrient Uptake
18. Assessment of Azafenidin for Weed Control in Wild Blueberries
19. Assessment of Rimsulfuron for Weed Control in Wild Blueberries
20. Assessment of Pendimethalin for Weed Control in Wild Blueberries
21. Evaluation and Demonstration of Techniques for Filling in Bare Spots in Wild Blueberry Fields
22. Assessment of Sprout-less Weeder for Hardwood Control in Wild Blueberries
23. Wild Blueberry Extension Education Program in 2001
24. Evaluation of Fungicide Efficacy in Wild Blueberry Fields
25. 2001 Pesticide Groundwater Survey
26. Cultural Weed Management Using Sulfur to Lower the pH
27. Wild Blueberry Web Sit
Longitudinal machine learning modeling of MS patient trajectories improves predictions of disability progression
Background and Objectives: Research in Multiple Sclerosis (MS) has recently focused on extracting knowledge from real-world clinical data sources. This type of data is more abundant than data produced during clinical trials and potentially more informative about real-world clinical practice. However, this comes at the cost of less curated and controlled data sets. In this work we aim to predict disability progression by optimally extracting information from longitudinal patient data in the real-world setting, with a special focus on the sporadic sampling problem. Methods: We use machine learning methods suited for patient trajectories modeling, such as recurrent neural networks and tensor factorization. A subset of 6682 patients from the MSBase registry is used. Results: We can predict disability progression of patients in a two-year horizon with an ROC-AUC of 0.85, which represents a 32% decrease in the ranking pair error (1-AUC) compared to reference methods using static clinical features. Conclusions: Compared to the models available in the literature, this work uses the most complete patient history for MS disease progression prediction and represents a step forward towards AI-assisted precision medicine in MS
Human Embryonic Stem Cell Technology: Large Scale Cell Amplification and Differentiation
Embryonic stem cells (ESC) hold the promise of overcoming many diseases as potential sources of, for example, dopaminergic neural cells for Parkinson’s Disease to pancreatic islets to relieve diabetic patients of their daily insulin injections. While an embryo has the innate capacity to develop fully functional differentiated tissues; biologists are finding that it is much more complex to derive singular, pure populations of primary cells from the highly versatile ESC from this embryonic parent. Thus, a substantial investment in developing the technologies to expand and differentiate these cells is required in the next decade to move this promise into reality. In this review we document the current standard assays for characterising human ESC (hESC), the status of ‘defined’ feeder-free culture conditions for undifferentiated hESC growth, examine the quality controls that will be required to be established for monitoring their growth, review current methods for expansion and differentiation, and speculate on the possible routes of scaling up the differentiation of hESC to therapeutic quantities
Identification of IKr Kinetics and Drug Binding in Native Myocytes
Determining the effect of a compound on IKr is a standard screen for drug safety. Often the effect is described using a single IC50 value, which is unable to capture complex effects of a drug. Using verapamil as an example, we present a method for using recordings from native myocytes at several drug doses along with qualitative features of IKr from published studies of HERG current to estimate parameters in a mathematical model of the drug effect on IKr. IKr was recorded from canine left ventricular myocytes using ruptured patch techniques. A voltage command protocol was used to record tail currents at voltages from −70 to −20 mV, following activating pulses over a wide range of voltages and pulse durations. Model equations were taken from a published IKr Markov model and the drug was modeled as binding to the open state. Parameters were estimated using a combined global and local optimization algorithm based on collected data with two additional constraints on IKrI–V relation and IKr inactivation. The method produced models that quantitatively reproduce both the control IKr kinetics and dose dependent changes in the current. In addition, the model exhibited use and rate dependence. The results suggest that: (1) the technique proposed here has the practical potential to develop data-driven models that quantitatively reproduce channel behavior in native myocytes; (2) the method can capture important drug effects that cannot be reproduced by the IC50 method. Although the method was developed for IKr, the same strategy can be applied to other ion channels, once appropriate channel-specific voltage protocols and qualitative features are identified
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