julilili42/papers huggingface dataset:
Towards scalability in niching methods
2010-07-01

The scaling properties of multimodal optimization methods have seldom been studied, and existing studies often concentrated on the idea that all local optima of a multimodal function can be found and their number can be estimated a priori. We argue that this approach is impractical for complex, high-dimensional target functions, and we formulate alternative criteria for scalable multimodal optimization methods. We suggest that a scalable niching method should return the more local optima the longer it is run, without relying on a fixed number of expected optima. This can be fulfilled by sequential and semi-sequential niching methods, several of which are presented and analyzed in that respect. Results show that, while sequential local search is very successful on simpler functions, a clustering-based particle swarm approach is most successful on multi-funnel functions, offering scalability even under deceptive multimodality, and denoting it a starting point towards effective scalable niching.
Optimization of the energy extraction of a shallow geothermal system
2010-07-01

Geothermal energy use from shallow groundwater systems is attractive for the supply of heat and hot water to buildings. It offers economic and environmental advantages over traditional fossil-fuel based technologies, in particular when large scale systems are well adapted to the always unique hydrogeological conditions. Computer based numerical simulations are used to examine the performance of multiple borehole heat exchangers installed in the ground. This paper demonstrates how evolutionary algorithms can be utilized to configure the elements of a geothermal system in an ideal way, and thus substantially enhance the energy extraction rate in comparison to standardized approaches. Differential evolution (DE), evolution strategies (ES) and particle swarm optimizers (PSO) are combined with a local search approach and compared with respect to their efficiency in the optimization of synthetic, real case oriented and static systems. First results are promising, especially for the PSO and the DE with the local search approach.
Properties and distribution of paired candidate stony meteorites at Meridiani Planum, Mars
2010-07-01

The Mars Exploration Rover Opportunity investigated four rocks, informally dubbed Barberton, Santa Catarina, Santorini, and Kasos, that are possible stony meteorites. Their chemical and mineralogical composition is similar to the howardite, eucrite, and diogenite group but with additional metal, similar to mesosiderite silicate clasts. Because of their virtually identical composition and because they appear to represent a relatively rare group of meteorites, they are probably paired. The four rocks were investigated serendipitously several kilometers apart, suggesting that Opportunity is driving across a larger population of similar rock fragments, maybe a meteorite strewn field. Small amounts of ferric Fe are a result of weathering. We did not observe evidence for fusion crusts. Four iron meteorites were found across the same area. Although mesosiderites are stony irons, a genetic link to these irons is unlikely. The stony meteorites probably fell later than the irons. The current atmosphere is sufficiently dense to land such meteorites at shallow entry angles, and it would disperse fragments over several kilometers upon atmospheric breakup. Alternatively, dispersion by spallation from an impacting meteoroid may have occurred. Santa Catarina and a large accumulation of similar rocks were found at the rim of Victoria crater. It is possible that they are associated with the impactor that created Victoria crater, but our limited knowledge about their distribution cannot exclude mere coincidence.
Mutational Mapping of UL130 of Human Cytomegalovirus Defines Peptide Motifs within the C-Terminal Third as Essential for Endothelial Cell Infection
2010-07-01

ABSTRACT The UL130 gene is one of the major determinants of endothelial cell (EC) tropism of human cytomegalovirus (HCMV). In order to define functionally important peptides within this protein, we have performed a charge-cluster-to-alanine (CCTA) mutational scanning of UL130 in the genetic background of a bacterial artificial chromosome-cloned endotheliotropic HCMV strain. A total of 10 charge clusters were defined, and in each of them two or three charged amino acids were replaced with alanines. While the six N-terminal clusters were phenotypically irrelevant, mutation of the four C-terminal clusters each caused a reduction of EC tropism. The importance of this protein domain was further emphasized by the fact that the C-terminal pentapeptide PNLIV was essential for infection of ECs, and the cell tropism could not be rescued by a scrambled version of this sequence. We conclude that the C terminus of the UL130 protein serves an important function for infection of ECs by HCMV. This makes UL130 a promising molecular target for antiviral strategies, e.g., the development of antiviral peptides.
Reduction of Dipyrido Ureas via 6-Alkyloxydipyrido[1,2-c;2´,1´-e]imidazolium Salts
2010-07-01

Dipyrido uronium salts can readily be synthesized by alkylation of dipyrido ureas with Meerwein’s reagent. Compared to the corresponding ureas, the uronium salts are more reactive towards basic or reducing agents like metal hydrides. Reactivity studies show that the uronium salts can react as alkylating agents towards DMSO, DBU and NaOEt along with release of the respective dipyrido ureas. In contrast, reduction of the dipyrido uronium salts with sodium borohydride or sodium trimethoxyborohydride in dry and degassed acetonitrile leads to the imidazolium salts 7a and 7b in moderate yields. Analysis of the by-products reveals an in situ carbene formation which can be reversed by using degassed but wet acetonitrile as solvent. The yield of 7b was increased significantly by these means.
Determining crop-production functions using multi-objective evolutionary algorithms
2010-07-01

The determination of crop production functions which describe the relationship between irrigation water and crop yield under the assumption of optimal irrigation scheduling is a major building block for a more efficient and sustainable water management. In this paper we introduce a methodology to determine the entire crop production function for a given scenario within a single run of a multi-objective evolutionary algorithm. Further we compare the performance of four major algorithms (NSGA-II, NSDE, DEMO, and MO-CMA-ES), and a single-objective approach based on differential evolution on three different scenarios and two different population initialization methods on this problem. We show that the combination of a problem specific initialization with MO-CMA-ES is able to determine crop production functions which are extremely close to actual ones.
Vitamin D levels of XP-patients under stringent sun-protection
2010-07-01

Xeroderma pigmentosum (XP) is a rare autosomal recessive disorder characterized by an increased skin cancer risk due to defective repair of ultraviolet (UV)-radiation induced DNA damage. Therefore patients with XP are required to apply stringent sun-protection. Since the skin needs UV-B irradiation for de novo vitamin D synthesis, it has been postulated that sun-protection may lead to a clinically relevant reduction of vitamin D levels. To investigate whether reduced vitamin D levels in XP-patients are caused by the stringent sun-protection measures employed, in this study we examined 15 patients with XP. The 25-hydroxyvitamin (25-OHD) and 1,25-dihydroxyvitamin D (1,25-(OH)2D) serum levels were measured. Additionally, patients received a questionnaire about their sun-protection-behaviour. Serum levels for 25-OHD were decreased in 10 of 15 (67%) patients, however there was no statistically significant association between decreased 25-OHD serum levels and duration of sun-protection (p = 0.84). Results for 1,25-(OH)2D levels showed a probability of < 0.16 and between 0.16 and 0.77 for sun-protection duration of < 20 and 20 to 40 years, respectively (p = 0.0058). There was no statistically significant association between the duration of sun-protection with drometrizole trisiloxane and the probability of reduced 25-OHD and 1,25-(OH)2D levels. In conclusion, this investigation indicates that vitamin D serum levels in patients with XP may be normal, increased or decreased but this is not causally linked to the stringent photoprotective measures carried out in our group of investigated XP-patients.
Simplified simulation of steady state bioreactive transport with kinetic solute uptake by the biomass
2010-07-01

Biodegradation of continuously emitted compounds that need a dissolved reaction partner, which is not jointly introduced with the contaminant into the subsurface, is mainly controlled by transverse dispersive mixing. Previous analytical approaches of evaluating mixing‐controlled bioreactive transport in steady state have been based on the assumption that the bulk aqueous‐phase concentration of the reactants is directly available to the specific biomass catalyzing the reaction. These models predict a very narrow stripe of active biomass with high specific biomass concentration. Experimental studies have indicated that such behavior may be unrealistic, particularly for anaerobic biodegradation. I extend the previous analysis to include kinetic solute uptake by the biomass, expressed as a first‐order mass‐transfer process coupled to dual Monod kinetics in the bio‐available domain. The approach is based on the evaluation of conservative components undergoing advective‐dispersive transport, the solution of a quadratic speciation problem within the immobile bio domain, and iterative simulation of linear transport of a single reactive constituent in steady state. Convergence is typically achieved within less than ten iterations. The comparison with simulations assuming instantaneous solute uptake by the biomass indicate that mass‐transfer kinetics may explain larger overlap of reactive constituents and a wider spatial distribution of specific biomass observed in experiments. Depending on the rate coefficient of mass transfer, the overall transformation of the contaminant may be significantly reduced or only slightly shifted to a region farther downstream.
Mineralogy and chemistry of cobbles at Meridiani Planum, Mars, investigated by the Mars Exploration Rover Opportunity
2010-07-01

Numerous loose rocks with dimensions of a few centimeters to tens of centimeters and with no obvious physical relationship to outcrop rocks have been observed along the traverse of the Mars Exploration Rover Opportunity. To date, about a dozen of these rocks have been analyzed with Opportunity's contact instruments, providing information about elemental chemistry (Alpha Particle X‐ray Spectrometer), iron mineralogy and oxidation states (Mössbauer Spectrometer) and texture (Microscopic Imager). These “cobbles” appear to be impact related, and three distinct groups can be identified on the basis of chemistry and mineralogy. The first group comprises bright fragments of the sulfate‐rich bedrock that are compositionally and texturally indistinguishable from outcrop rocks. All other cobbles are dark and are divided into two groups, referred to as the “Barberton group” and the “Arkansas group,” after the first specimen of each that was encountered by Opportunity. Barberton group cobbles are interpreted as meteorites with an overall chemistry and mineralogy consistent with a mesosiderite silicate clast composition. Arkansas group cobbles appear to be related to Meridiani outcrop and contain an additional basaltic component. They have brecciated textures, pointing to an impact‐related origin during which local bedrock and basaltic material were mixed.
Visible and near‐infrared multispectral analysis of geochemically measured rock fragments at the Opportunity landing site in Meridiani Planum
2010-07-01

We have used visible and near‐infrared Panoramic Camera (Pancam) spectral data acquired by the Opportunity rover to analyze 15 rock fragments at the Meridiani Planum landing site. These spectral results were then compared to geochemistry measurements made by the in situ instruments Mössbauer (MB) and Alpha Particle X‐ray Spectrometer (APXS) to determine the feasibility of mineralogic characterization from Pancam data. Our results suggest that dust and alteration rinds coat many rock fragments, which limits our ability to adequately measure the mineralogy of some rocks from Pancam spectra relative to the different field of view and penetration depths of MB and APXS. Viewing and lighting geometry, along with sampling size, also complicate the spectral characterization of the rocks. Rock fragments with the same geochemistry of sulfate‐rich outcrops have similar spectra, although the sulfate‐rich composition cannot be ascertained based upon Pancam spectra alone. FeNi meteorites have spectral characteristics, particularly ferric oxide coatings, that generally differentiate them from other rocks at the landing site. Stony meteorites and impact fragments with unknown compositions have a diverse range of spectral properties and are not well constrained nor diagnostic in Pancam data. Bounce Rock, with its unique basalt composition, is easily differentiated in the Pancam data from all other rock types at Meridiani Planum. Our Pancam analyses of small pebbles adjacent to these 15 rock fragments suggests that other rock types may exist at the landing site but have not yet been geochemically measured.
Methodological aspects of the electron-beam investigation of dielectric target charging
2010-07-01

The basic characteristics of dielectric target charging with (2–30)-keV electron beams were investigated using the example of a typical insulator, Al2O3. A new hypothetical scenario of dielectric charging, based on the reduction of secondary-electron current due to the formation of polarized excitons in the positive layer of a charged target, is proposed on the basis of modeling calculations and the experimental data.
Some Personal Memories of Otto Scherzer
2010-07-01

At last year's M&amp;M meeting, the birth centennial of Otto Scherzer, one of the pioneers of electron optics and particularly the correction of electron-optical lenses, was remembered in a special symposium. His scientific achievements have been extensively described in an article by Marko and Rose (2010). Here we try to recollect some personal memories of Otto Scherzer from the time we spent at the “Institut für theoretische Physik” at the Technische Hochschule Darmstadt (now Technische Universität Darmstadt).
Experiments on formation switching for mobile robots
2010-07-01

In this paper, we address the problem of distributed role assignment for multiple mobile robots. This problem arises when a mobile robot in the team must decide what role to take on in a desired formation configuration. In some applications, in which the center and the orientation of a desired formation are not predetermined, the rotation and translation of the formation can be computed by using average consensus protocols. However, a conflict arises when the same role is assigned to more than one robot. This problem is resolved by using a negotiation strategy, while each assigned robot is traveling to the target position. We evaluate our proposed framework through two experiments on a team of physical nonholonomic mobile robots, i.e., (i) robots reconfigure themselves from one formation to another, and (ii) formation switching happens, while each robot is following a reference path.
O4‐05‐05: Modeling familial danish dementia: Implications for the amyloid hypothesis of Alzheimer's disease
2010-07-01

Familial Danish Dementia (FDD) is a neurodegenerative disease with cerebral deposition of Dan-amyloid (ADan), neuroinflammation, and neurofibrillary tangles - hallmark characteristics remarkably similar to those in Alzheimer's disease (AD). We have generated transgenic mouse models of FDD that recapitulate the deposition of ADan throughout the brain as well as the associated amyloid angiopathy, microhemorrhage, neuritic dystrophy, and neuroinflammation seen in Danish patients. Furthermore, ADanPP tg mice are impaired in the Morris water maze and exhibit increased anxiety in the open field. To advance our understanding of disease pathogenesis and that of amyloid hypotheses in general, we have used this model of non-ABeta amyloidosis to investigate whether ADan, ABeta, and Tau participate in similar disease-related pathways. ADanPP tg mice were cross-bred to models that exhibit ABeta-amyloidosis and Tau tangle formation. Offspring from these crosses were analysed for changes in beta-amyloid plaque and Tau tangle formation using histochemical and biochemical methods. When crossed with TauP301S mice, ADan accumulation induced neurofibrillary lesions, in all aspects similar to the Tau lesions observed in crosses between beta-amyloid depositing mice and TauP301S mice. While these observations argue for shared mechanisms of downstream pathophysiology for the sequence-unrelated ADan and ABeta peptides, the lack of co-deposition of these peptides in crosses of ADan- and ABeta-depositing APPPS1 mice also points to distinguishing properties of the two peptides. Our results suggest that different proteins prone to amyloid formation can drive strikingly similar pathogenic pathways in the brain. Further investigation of common disease pathways is likely to shed light on key upstream therapeutic targets.
O4‐05‐07: The role of immune cells in mouse models of cerebral amyloidosis
2010-07-01

In Alzheimer's disease (AD) microglia, the immune effector cells of the brain, are found in close vicinity to β-amyloid (Aβ) plaques, which is one of the pathological hallmarks of the disease. Recently, we have shown that almost complete ablation of resident microglia in a mouse model of cerebral β-amyloidosis does not alter the formation or maintenance of Aβ deposits (Grathwohl et al., Nature Neuroscience, 2009,12:1361-3). Numerous studies have indicated that in similar transgenic mouse models of cerebral β-amyloidosis blood-derived monocytic cells (BDMC) can enter the brain and migrate to areas of Aβ deposition. However, the exact role and significance of BDMC in AD pathogenesis and progression remains unresolved. A novel method of reconstituting the brain with BDMC in the absence of resident microglial cells was developed. In brief, CD11b-HSVTK (TK mice) are exposed to the toxic thymidine analog Ganciclovir (GCV) for two weeks to ablate microglia. GCV treatment is then terminated, which is followed by a rapid infiltration of the brain with BDMC. By applying an irradiation-independent assay we show that after microglial ablation in TK mice BDMC migrate into and distribute evenly throughout the brain developing a ramified morphology different from resident microglial cells. When TK mice were bred to APPPS1 transgenic mice a similar brain invasion of BDMC was observed in response to microglia ablation. Surprisingly, infiltrating BDMC did not migrate towards newly formed or existing Aβ plaques in APPPS1/TK mice. We provide a new experimental approach to investigate the role of BDMC for brain function and brain disease. Our data suggest that without further activation BDMC show a limited role in cerebral amyloidosis of APPPS1 transgenic mice.
Die Waltherschen Totenklagen auf Reinmar
2010-07-01

The Walther corpus includes two obituaries dedicated to the minnesinger Reinmar which share the same style. With regard to the personal evaluation of the fellow singer, however, they are simply irreconcilable with each other. To resolve this problem, the statement in L.82,24 has to be reflected in a critical way, along with a new look at the performative orientation of L.83,1. This serves to verify how the two stanzas are linked to reality and to reconcile them with the confusion evoked by their contradictory nature.
P1‐181: Various inoculation routes of Aβ‐containing brain extract in APP‐tg mice
2010-07-01

Cerebral β-amyloidosis is a histopathological hallmark of Alzheimer's disease (AD) in the form of parenchymal as well as vascular Aβ deposits. However, little is known about the initiation of Aβ aggregation in vivo. We recently reported that the intracerebral injection of dilute extracts from the brains of humans with AD or from aged amyloid precursor protein (APP) transgenic (tg) mice induces cerebral β-amyloidosis (Meyer-Luehmann et al., Science 313: 1781, 2006). Although these observations are reminiscent of a prion-like mechanism, our initial studies revealed no evidence that peripheral inoculations with the Aβ-containing brain extract could likewise induce cerebral β-amyloidosis (Eisele et al., Proc Natl Acad Sci U S A: 106, 2009). However, induction of cerebral β-amyloidosis is a concentration- and time-dependent process. In addition, peripheral expression of human APP/Aβ may be necessary for propagation of Aβ aggregation from the periphery to the brain, similar to findings in prion research. We therefore extended our peripheral Aβ inoculation studies applying higher amounts of Aβ-containing brain extract, increasing the post-inoculation observation period, and using host mice with peripheral APP expression. Predepositing APP transgenic mice (APP23 or R1.40) served as model systems to assess induction of cerebral β-amyloidosis. In addition to cerebral injections, the following routes of peripheral inoculation were investigated: oral, intraperitoneal, intravenous, intraocular and intranasal. Immunohistochemistry and Western blot were used to investigate Aβ deposition. Induction of Aβ deposition in R1.40 mice is very similar, albeit, less than in APP23 mice 4 months after intracerebral injections of highly dilute brain extracts from aged APP23 mice. In addition, we found first evidence for induction of cerebral β-amyloid deposition after peripheral inoculations of APP tg mice after long incubation times. In response to peripheral extract application circulating Aβ-immunoreactive blood monocytes were found. Our results indicate that minute amounts of Aβ-containing brain extract induces cerebral β-amyloidosis. Ongoing results will reveal whether peripheral inoculations after extended observation times and in hosts with peripheral APP/Aβ expression will also induce cerebral β-amyloidosis.