381 research outputs found

    Ternary Syndrome Decoding with Large Weight

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    The Syndrome Decoding problem is at the core of many code-based cryptosystems. In this paper, we study ternary Syndrome Decoding in large weight. This problem has been introduced in the Wave signature scheme but has never been thoroughly studied. We perform an algorithmic study of this problem which results in an update of the Wave parameters. On a more fundamental level, we show that ternary Syndrome Decoding with large weight is a really harder problem than the binary Syndrome Decoding problem, which could have several applications for the design of code-based cryptosystems

    An Optimal Algorithm for Tiling the Plane with a Translated Polyomino

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    We give a O(n)O(n)-time algorithm for determining whether translations of a polyomino with nn edges can tile the plane. The algorithm is also a O(n)O(n)-time algorithm for enumerating all such tilings that are also regular, and we prove that at most Θ(n)\Theta(n) such tilings exist.Comment: In proceedings of ISAAC 201

    Solving Medium-Density Subset Sum Problems in Expected Polynomial Time: An Enumeration Approach

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    The subset sum problem (SSP) can be briefly stated as: given a target integer EE and a set AA containing nn positive integer aja_j, find a subset of AA summing to EE. The \textit{density} dd of an SSP instance is defined by the ratio of nn to mm, where mm is the logarithm of the largest integer within AA. Based on the structural and statistical properties of subset sums, we present an improved enumeration scheme for SSP, and implement it as a complete and exact algorithm (EnumPlus). The algorithm always equivalently reduces an instance to be low-density, and then solve it by enumeration. Through this approach, we show the possibility to design a sole algorithm that can efficiently solve arbitrary density instance in a uniform way. Furthermore, our algorithm has considerable performance advantage over previous algorithms. Firstly, it extends the density scope, in which SSP can be solved in expected polynomial time. Specifically, It solves SSP in expected O(nlogn)O(n\log{n}) time when density dcn/lognd \geq c\cdot \sqrt{n}/\log{n}, while the previously best density scope is dcn/(logn)2d \geq c\cdot n/(\log{n})^{2}. In addition, the overall expected time and space requirement in the average case are proven to be O(n5logn)O(n^5\log n) and O(n5)O(n^5) respectively. Secondly, in the worst case, it slightly improves the previously best time complexity of exact algorithms for SSP. Specifically, the worst-case time complexity of our algorithm is proved to be O((n6)2n/2+n)O((n-6)2^{n/2}+n), while the previously best result is O(n2n/2)O(n2^{n/2}).Comment: 11 pages, 1 figur

    DIGESTIBILITY AND SOME PERFORMANCE PARAMETERS FOR SHEEP FEEDING ON DATE SEED TREATED WITH BACTERIA

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    This paper focuses on treated date seed with two cellulolytic bacteria (Acetobacter xylinum and Thermonospora fusca) isolated from sheep and evaluated these species by Invitro gas production and metabolism trail.  We evaluated the influence of many rations contain several percentage from date seed untreated and treated on In vitro traild for DM,OM, NDF, ADF, cellulose and hemicellulose disappeara (samples incubated for 24 hrs). the best ration used in metabolism trail . The experimental work was conducted in 2017, at the Department of Animal Production, faculty of agriculture, Ain Shams University, Cairo, Egypt and the experiment of the farm animals occurred in the Animal Production research institute.  Our results in this revealed that the ration content 25% untreated and treated with bacteria  had significant values on NDF, ADF and hemicellulose degradability after 24 hours, especially treatment 2 (Thermonospora fusca) of date seed. In  the experimental ration with ascending level of untreated and treated date seed  had not significant effect on pH value while more effect on total gas production (GP),ammonia, TVFA’s, MP, EMP and  metabolizable energy ME (Mcal/ g). The differences were significant (P<0.05) between control ration and other experimental  rations. Furthermore, ration content date seed treated (R3) had the highest values of DM, OM, CF and EE digestibility. It could be noticed that improving CP, CF and cell wall constituents (NDF, ADF, hemicellulose and cellulose) digestibility may be due to the increasing number of rumen cellulolytic bacteria. In conclusion, the bacterial treatment (Acetobacter xylinum and Thermonospora fusca) with date seed successfully to improve chemical compostion of date seed and Invitro digestiability specially ration contain 25% from total dry matter.  It showed that the strain (Thermonospora fusca) was  the best in In vitro fermentation . Digestibility indicated that ration contain treated date seed (R3) was high DM, OM, ADF and nitrogen than other rations.  It was concluded that treated date seed can replace concentrate in rations and improve In vitro degradability, digestibility trail and no effect on rumen and blood parameters without adversely affecting on helthy animals

    Serotonin 5-HT4 receptor boosts functional maturation of dendritic spines via RhoA-dependent control of F-actin

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    Activity-dependent remodeling of excitatory connections underpins memory formation in the brain. Serotonin receptors are known to contribute to such remodeling, yet the underlying molecular machinery remains poorly understood. Here, we employ high-resolution time-lapse FRET imaging in neuroblastoma cells and neuronal dendrites to establish that activation of serotonin receptor 5-HT4 (5-HT4R) rapidly triggers spatially-restricted RhoA activity and G13-mediated phosphorylation of cofilin, thus locally boosting the filamentous actin fraction. In neuroblastoma cells, this leads to cell rounding and neurite retraction. In hippocampal neurons in situ, 5-HT4R-mediated RhoA activation triggers maturation of dendritic spines. This is paralleled by RhoA-dependent, transient alterations in cell excitability, as reflected by increased spontaneous synaptic activity, apparent shunting of evoked synaptic responses, and enhanced long-term potentiation of excitatory transmission. The 5-HT4R/G13/RhoA signaling thus emerges as a previously unrecognized molecular pathway underpinning use-dependent functional remodeling of excitatory synaptic connections

    An environmental assessment of risk in achieving good environmental status to support regional prioritisation of management in Europe

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    The Marine Strategy Framework Directive (MSFD) aims to achieve Good Environmental Status (GES) in Europe's Seas. The requirement for regional sea authorities to identify and prioritise issues for management has meant that standardized methods to assess the current level of departure from GES are needed. The methodology presented here provides a means by which existing information describing the status of ecosystem components of a regional sea can be used to determine the effort required to achieve GES. A risk assessment framework was developed to score departure from GES for 10 out of the 11 GES descriptors, based on proposed definitions of 'good' status, and current knowledge of environmental status in each of the four regional seas (North-East Atlantic, Mediterranean Sea, Baltic Sea and Black Sea). This provides an approach for regional evaluation of environmental issues and national prioritisation of conservation objectives. Departure from GES definitions is described as 'high', 'moderate' or low' and the implications for management options and national policy decisions are discussed. While the criteria used in this study were developed specifically for application toward MSFD objectives, with modification the approach could be applied to evaluate other high-level social, economic or environmental objectives. Crown Copyright (C) 2012 Published by Elsevier Ltd. All rights reserved

    The PINE study: rationale and design of a randomised comparison of epidural injection of local anaesthetics and steroids versus care-as-usual to prevent postherpetic neuralgia in the elderly [ISRCTN32866390]

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    BACKGROUND: Postherpetic neuralgia (PHN) is by far the most common complication of herpes zoster (HZ) and one of the most intractable pain disorders. Since PHN is seen most often in the elderly, the number of patients with this disorder is expected to increase in our ageing society. PHN may last for months to years and has a high impact on the quality of life. The results of PHN treatment are rather disappointing. Epidural injection of local anaesthetics and steroids in the acute phase of HZ is a promising therapy for the prevention of PHN. Since randomised trials on the effectiveness of this intervention are lacking, the PINE (Prevention by epidural Injection of postherpetic Neuralgia in the Elderly) study was set up. The PINE study compares the effectiveness and cost-effectiveness of a single epidural injection of local anaesthetics and steroids during the acute phase of HZ with that of care-as-usual (i.e. antivirals and analgesics) in preventing PHN in elderly patients. METHODS / DESIGN: The PINE study is an open, multicenter clinical trial in which 550 elderly (age ≥ 50 yr.) patients who consult their general practitioner in the acute phase of HZ (rash < 7 days) are randomised to one of the treatment groups. The primary clinical endpoint is the presence of HZ-related pain one month after the onset of the rash. Secondary endpoints include duration and severity of pain, re-interventions aiming to treat the existing pain, side effects, quality of life, and cost-effectiveness. CONCLUSION: The PINE study is aimed to quantify the (cost-) effectiveness of a single epidural injection during the acute phase of HZ on the prevention of PHN

    The Biodiversity of the Mediterranean Sea: Estimates, Patterns, and Threats

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    The Mediterranean Sea is a marine biodiversity hot spot. Here we combined an extensive literature analysis with expert opinions to update publicly available estimates of major taxa in this marine ecosystem and to revise and update several species lists. We also assessed overall spatial and temporal patterns of species diversity and identified major changes and threats. Our results listed approximately 17,000 marine species occurring in the Mediterranean Sea. However, our estimates of marine diversity are still incomplete as yet—undescribed species will be added in the future. Diversity for microbes is substantially underestimated, and the deep-sea areas and portions of the southern and eastern region are still poorly known. In addition, the invasion of alien species is a crucial factor that will continue to change the biodiversity of the Mediterranean, mainly in its eastern basin that can spread rapidly northwards and westwards due to the warming of the Mediterranean Sea. Spatial patterns showed a general decrease in biodiversity from northwestern to southeastern regions following a gradient of production, with some exceptions and caution due to gaps in our knowledge of the biota along the southern and eastern rims. Biodiversity was also generally higher in coastal areas and continental shelves, and decreases with depth. Temporal trends indicated that overexploitation and habitat loss have been the main human drivers of historical changes in biodiversity. At present, habitat loss and degradation, followed by fishing impacts, pollution, climate change, eutrophication, and the establishment of alien species are the most important threats and affect the greatest number of taxonomic groups. All these impacts are expected to grow in importance in the future, especially climate change and habitat degradation. The spatial identification of hot spots highlighted the ecological importance of most of the western Mediterranean shelves (and in particular, the Strait of Gibraltar and the adjacent Alboran Sea), western African coast, the Adriatic, and the Aegean Sea, which show high concentrations of endangered, threatened, or vulnerable species. The Levantine Basin, severely impacted by the invasion of species, is endangered as well

    Effect of invader removal: pollinators stay but some native plants miss their new friend

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    Removal of invasive species often benefits biological diversity allowing ecosystems’ recovery. However, it is important to assess the functional roles that invaders may have established in their new areas to avoid unexpected results from species elimination. Invasive animal-pollinated plants may affect the plant–pollination interactions by changing pollinator availability and/or behaviour in the community. Thus, removal of an invasive plant may have important effects on pollinator community that may then be reflected positive or negatively on the reproductive success of native plants. The objective of this study was to assess the effect of removing Oxalis pescaprae, an invasive weed widely spread in the Mediterranean basin, on plant–pollinator interactions and on the reproductive success of co-flowering native plants. For this, a disturbed area in central Portugal, where this species is highly abundant, was selected. Visitation rates, natural pollen loads, pollen tube growth and natural fruit set of native plants were compared in the presence of O. pes-caprae and after manual removal of their flowers. Our results showed a highly resilient pollination network but also revealed some facilitative effects of O. pes-caprae on the reproductive success of co-flowering native plants. Reproductive success of the native plants seems to depend not only on the number and diversity of floral visitors, but also on their efficiency as pollinators. The information provided on the effects of invasive species on the sexual reproductive success of natives is essential for adequate management of invaded areas.This work is financed by FEDER funds through the COMPETE Program and by Portuguese Foundation for Science and Technology (FCT) funds in the ambit of the project PTDC/ BIA-BIC/110824/2009, by CRUP Acc¸o˜es Integradas Luso- Espanholas 2010 with the project E10/10, by MCI-Programa de Internacionalizacio´n de la I ? D (PT2009-0068) and by the Spanish DGICYT (CGL2009-10466), FEDER funds from the European Union, and the Xunta de Galicia (INCITE09- 3103009PR). FCT also supported the work of S. Castro (FCT/ BPD/41200/2007) and J. Costa (CB/C05/2009/209; PTDC/ BIA-BIC/110824/2009). The work of V. Ferrero was supported by the Fundacio´n Ramo´n Areces
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