974 resultados para Subset Sum Problem
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The existence of a new class of inclined periodic orbits of the collision restricted three-body problem is shown. The symmetric periodic solutions found are perturbations of elliptic kepler orbits and they exist only for special values of the inclination and are related to the motion of a satellite around an oblate planet
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Forensic scientists face increasingly complex inference problems for evaluating likelihood ratios (LRs) for an appropriate pair of propositions. Up to now, scientists and statisticians have derived LR formulae using an algebraic approach. However, this approach reaches its limits when addressing cases with an increasing number of variables and dependence relationships between these variables. In this study, we suggest using a graphical approach, based on the construction of Bayesian networks (BNs). We first construct a BN that captures the problem, and then deduce the expression for calculating the LR from this model to compare it with existing LR formulae. We illustrate this idea by applying it to the evaluation of an activity level LR in the context of the two-trace transfer problem. Our approach allows us to relax assumptions made in previous LR developments, produce a new LR formula for the two-trace transfer problem and generalize this scenario to n traces.
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Amino-N is preserved because of the scarcity and nutritional importance of protein. Excretion requires its conversion to ammonia, later incorporated into urea. Under conditions of excess dietary energy, the body cannot easily dispose of the excess amino-N against the evolutively adapted schemes that prevent its wastage; thus ammonia and glutamine formation (and urea excretion) are decreased. High lipid (and energy) availability limits the utilisation of glucose, and high glucose spares the production of ammonium from amino acids, limiting the synthesis of glutamine and its utilisation by the intestine and kidney. The amino acid composition of the diet affects the production of ammonium depending on its composition and the individual amino acid catabolic pathways. Surplus amino acids enhance protein synthesis and growth, and the synthesis of non-protein-N-containing compounds. But these outlets are not enough; consequently, less-conventional mechanisms are activated, such as increased synthesis of NO∙ followed by higher nitrite (and nitrate) excretion and changes in the microbiota. There is also a significant production of N(2) gas, through unknown mechanisms. Health consequences of amino-N surplus are difficult to fathom because of the sparse data available, but it can be speculated that the effects may be negative, largely because the fundamental N homeostasis is stretched out of normalcy, forcing the N removal through pathways unprepared for that task. The unreliable results of hyperproteic diets, and part of the dysregulation found in the metabolic syndrome may be an unwanted consequence of this N disposal conflict.
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The objective of this work was to evaluate basal temperature, thermal sum at different phenological stages, phenological phase duration, yield and seasonality of one nectarine and 14 peach cultivars, between 2006 and 2009. The considered phenological phases were: pruning-sprouting; sprouting-flowering, from swollen bud to open flower; flowering-fruiting, from petal fall to medium-sized fruit; and ripening. Minimum basal temperatures (Tb) obtained were: pruning-sprouting, 8°C, irrespective of the cultivars; sprouting-flowering, 10°C, except for 'Cascata 968', which required 8°C Tb; flowering-fruiting, 12°C, except for 'Oro Azteca', which required 14°C Tb; ripening, 14°C, except for 'Sunblaze', 'Diamante Mejorado' and 'Precocinho' with 12°C Tb. For most cultivars, the maximum basal temperatures were 30, 34, 34 and 28ºC for phases pruning-sprouting, sprouting-flowering, flowering-fruiting and ripening, respectively. 'Turmalina', 'Marli' and 'Tropic Beauty' showed average yields of 3,945.0, 3,969.3 and 3,954.0 kg ha-1, respectively, in 2009, while the nectarine 'Sunblaze' showed around 3,900 kg ha-1 in 2008 and 2009. The cultivars differed for their total cycle and for the accumulated thermal sums which varied, respectively, from 245 days and 1,881.4 degree-days for 'Oro Azteca', to144 days and 1,455.7 degree-days for 'Precocinho'.
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To defend the host from malignancies, the immune system can spontaneously raise CD8(+) T-cell responses against tumor antigens. Investigating the functional state of tumor-reactive cytolytic T cells in cancer patients is a key step for understanding the role of these cells in tumor immunosurveillance and for evaluating the potential of immunotherapeutic approaches of vaccination against cancer. In this study we identified a subset of circulating tumor-reactive CD8(+) T lymphocytes, which specifically secreted IFN-gamma after exposition to autologous tumor cell lines in stage IV metastatic melanoma patients. Additional phenotypic characterization using multicolor flow cytometry revealed that a significant fraction of these cells were CD45RA(+)CCR7(-), a phenotype that has been proposed recently to characterize cytolytic effectors potentially able to home into inflamed tissues. In the case of an HLA-A2-expressing patient, the antigen specificity of this population was identified by using HLA-A2/peptide multimers incorporating a tyrosinase-derived peptide. Consistently with their phenotypic characteristics, A2/tyrosinase peptide multimer(+) CD8(+) T cells, isolated by cell sorting, were directly lytic ex vivo and able to specifically recognize tyrosinase-expressing tumor cells. Overall, these results provide the first evidence that a proportion of melanoma patients have circulating tumor-reactive T cells, which are lytic effectors cells.
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Abstract
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Peer-reviewed
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The continuous wavelet transform is obtained as a maximumentropy solution of the corresponding inverse problem. It is well knownthat although a signal can be reconstructed from its wavelet transform,the expansion is not unique due to the redundancy of continuous wavelets.Hence, the inverse problem has no unique solution. If we want to recognizeone solution as "optimal", then an appropriate decision criterion hasto be adopted. We show here that the continuous wavelet transform is an"optimal" solution in a maximum entropy sense.
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The General Assembly Line Balancing Problem with Setups (GALBPS) was recently defined in the literature. It adds sequence-dependent setup time considerations to the classical Simple Assembly Line Balancing Problem (SALBP) as follows: whenever a task is assigned next to another at the same workstation, a setup time must be added to compute the global workstation time, thereby providing the task sequence inside each workstation. This paper proposes over 50 priority-rule-based heuristic procedures to solve GALBPS, many of which are an improvement upon heuristic procedures published to date.
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A maximum entropy statistical treatment of an inverse problem concerning frame theory is presented. The problem arises from the fact that a frame is an overcomplete set of vectors that defines a mapping with no unique inverse. Although any vector in the concomitant space can be expressed as a linear combination of frame elements, the coefficients of the expansion are not unique. Frame theory guarantees the existence of a set of coefficients which is “optimal” in a minimum norm sense. We show here that these coefficients are also “optimal” from a maximum entropy viewpoint.
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Introduction: Trastuzumab (T) is a cornerstone in the treatment of patients with HER2-overexpressing advanced breast cancer and development of resistance to T is a major therapeutic problem. HER-2 is part of a highly interactive signaling network that may impair efficacy of endocrine therapy. A sequential treatment design was chosen in this trial to ensure complete resistance to single agent therapy before receiving both a non-steroidal aromatase inhibitor (AI) and T. Any kind of clinical activity with combined treatment of AI and T after progression of single agent treatments could indicate restoration of sensitivity as a consequence of cross-talking and networking between both pathways. Methods: Key eligibility criteria included postmenopausal patients (pts.) with advanced, measurable, HER-2 positive (assessed by FISH, ratio (≥2)), HR positive disease and progression on prior treatment with a non-steroidal AI, e.g. letrozole or anastrozole, either in an adjuvant or advanced setting. Pts. received standard dose T monotherapy either weekly or three-weekly in step 1 and upon disease progression, continued T in combination with letrozole in step 2. The primary endpoint was clinical benefit response (CBR: CR, PR or SD for at least 24 weeks (+/- 1 week) according to RECIST) in step 2. Results: Thirteen pts. were enrolled in five centers in Switzerland. In step 1, six pts. (46%) achieved CBR. Median time to progression (TTP) was 161 days (Range: 50 - 627). Based on data collected until the end of May 2010, CBR was observed in seven out of the eleven evaluable pts. (64%) in step 2, including one pt. with partial response. Four of the seven pts. within step 2 that achieved CBR also had CBR in step 1. Seven out of eleven pts. have documented tumor progression during step 2 treatment. Median TTP for all eleven pts. was 184 days (range 61 - 471). Mean time on study treatment (TTP in step 1 plus TTP in step 2) for pts. reaching step 2 was 380 days (range 174 - 864). Adverse events were generally mild. Conclusion: Results of this proof-of-principle trial suggest that complete resistance to both AI and T can be overcome in a proportion of pts. by combined treatment of AI and T, as all pts. served as their own control. Our results appear promising for a new treatment strategy which offers a chemotherapy-free and well-tolerated option for at least a subset of the pts. with HR positive, HER-2 positive breast cancer. Further trials will need to corroborate this finding.
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PURPOSE AND METHOD: This questionnaire survey of 190 university music students assessed negative feelings of music performance anxiety (MPA) before performing, the experience of stage fright as a problem, and how closely they are associated with each other. The study further investigated whether the experience of stage fright as a problem and negative feelings of MPA predict the coping behavior of the music students. Rarely addressed coping issues were assessed, i.e., self-perceived effectiveness of different coping strategies, knowledge of possible risks and acceptance of substance-based coping strategies, and need for more support.RESULTS: The results show that one-third of the students experienced stage fright as a problem and that this was only moderately correlated with negative feelings of MPA. The experience of stage fright as a problem significantly predicted the frequency of use and the acceptance of medication as a coping strategy. Breathing exercises and self-control techniques were rated as effective as medication. Finally, students expressed a strong need to receive more support (65%) and more information (84%) concerning stage fright.CONCLUSION: Stage fright was experienced as a problem and perceived as having negative career consequences by a considerable percentage of the surveyed students. In addition to a desire for more help and support, the students expressed an openness and willingness to seriously discuss and address the topic of stage fright. This provides a necessary and promising basis for optimal career preparation and, hence, an opportunity to prevent occupational problems in professional musicians. [Authors]
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Neurofilamentous changes in select groups of neurons are associated with the degenerative changes of many human age-related neurodegenerative diseases. To examine the possible effects of aging on the neuronal cytoskeleton containing human proteins, the retinas of transgenic mice expressing the gene for the human middle-sized neurofilament triplet were investigated at 3 or 12 months of age. Transgenic mice developed tangle-like neurofilamentous accumulations in a subset of retinal ganglion cells at 12 months of age. These neurofilamentous accumulations, which also involved endogenous neurofilament proteins, were present in the perikarya and proximal processes of large ganglion cells and were predominantly located in peripheral retina. The presence of the human protein may thus confer vulnerability of the cytoskeleton to age-related alterations in this specific retinal cell type and may serve as a model for similar cellular changes associated with Alzheimer's disease and glaucoma.
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A wide variety of whole cell bioreporter and biosensor assays for arsenic detection has been developed over the past decade. The assays permit flexible detection instrumentation while maintaining excellent method of detection limits in the environmentally relevant range of 10-50 μg arsenite per L and below. New emerging trends focus on genetic rewiring of reporter cells and/or integration into microdevices for more optimal detection. A number of case studies have shown realistic field applicability of bioreporter assays.
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Diplomityön tutkimusfunktio käsittelee toimeksiantajan, Stora Enso Timber Oy Ltd Kotkan sahan, sahalinjan optimointikokonaisuuden relevanttia ongelmakenttää. Tutkimuksen alussa profiloivan sahalinjan tukinpyörityksen, pelkan sivuttaissiirron tai sivulautaoptimoinnin toimivuudesta ei ollut varmuutta. Työn painopistealue on sivulautaoptimointi, jonka toimivuus tutkimuksen alussa on hyvin kyseenalaista tuotantoajossa. Työn tavoitteet kiteytyvät paremman raaka-aineen käyttösuhteen saavuttamiselle, jolloin pitkän aikajänteen kannattavuus on realistisempaa saavuttaa. Kotkan sahalinjan optimointijärjestelmässä on kokonaisuudessaan saavutettu tuotantoajoon hyväksyttävä taso. Tukinpyörityksen tarkkuudessa saavutettiin asetettu tavoite, eli 90 % pyöritystuloksista menee virheikkunaan ± 10° , sekä virheen keskiarvon itseisarvo jasen ympärillä olevan hajonnan summa on maksimissaan 10° . Pelkan sivuttaissiirto todettiin tutkimuksessa sekundääriseksi optimointijärjestelmäksi. Ohjaus perustuu tukkimittarin mittaamaan dataan, jolloin tukinpyörityksen hajonta aiheuttaa epätarkkuutta pelkan suuntauksessa. Pelkan sivuttaisiirron käyttäminen vaatii lisämittauksia, jolloin voidaan varmistua pelkan suuntauksen optimoinnin toimivuudesta. Sivulautaoptimoinnin toimivuuden kehittämisessä saavutettiin se taso, missä todellista kehitystyötä voidaan tehdä. Koeajoissa ja optimointiohjelman tarkastamisessa havaittiin periaatteellisia virheitä, jotka korjattiin. Toimivan sivulautaoptimoinnin myötä on mahdollista hallita paremmin tuotannonohjaus, jolloin tuotanto voidaan etenkin sivulautojen osalta kohdentaa paremmin vastaamaan kysyntää sekä asete-erän hyvää käyttösuhdetta. Raaka-aineen käyttösuhde on parantunut. Yksittäisten asetevertailujen sekä esimerkkilaskelmien perusteella tuottopotentiaali tukinpyörityksen ja sivulautaoptimoinnin osalta on 0,6...1,5 MEUR Välillinen tuottopotentiaali on suurempi, koska tuotantoprosessi sahauksen osalta on erittäin joustava markkinoiden tarpeen muutoksille. Sahalinjalla on mahdollista tuottaa helposti laajalla tukkisumalla laajaa tuotematriisia, jossa sivulautaoptimoinnilla on avainrooli. Tuotannonsuunnittelufunktiota tulee kehittää vastaamaan mahdollisuuksiin,joita sivulautaoptimointi tarjoaa. Tuotematriisi ja sitä vastaavat asetteet lankeavalla tukkisumalla tulee rakentaa uudestaan niiltä osin, joihin sivulautaoptimointi antaa variaatiomahdollisuuksia.