160 research outputs found

    Modelling Nonlinear Sequence Generators in terms of Linear Cellular Automata

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    In this work, a wide family of LFSR-based sequence generators, the so-called Clock-Controlled Shrinking Generators (CCSGs), has been analyzed and identified with a subset of linear Cellular Automata (CA). In fact, a pair of linear models describing the behavior of the CCSGs can be derived. The algorithm that converts a given CCSG into a CA-based linear model is very simple and can be applied to CCSGs in a range of practical interest. The linearity of these cellular models can be advantageously used in two different ways: (a) for the analysis and/or cryptanalysis of the CCSGs and (b) for the reconstruction of the output sequence obtained from this kind of generators.Comment: 15 pages, 0 figure

    Phytase-producing Bacillus sp. inoculation increases phosphorus availability in cattle manure

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    Organic wastes rich in phosphorus (P) are considered an alternative to decrease the dependence on chemical P fertilization in crops and pastures. Microbial inoculants are being studied as a tool to increase plant P availability in organic wastes. In this study, we explore the effect of inoculation with Bacillus sp. MQH-19 (a native phytase-producing bacterium) on the release of inorganic phosphorus (Pi) in cattle manure with low available P but a high total P content. Bacteria inoculation resulted in a higher release of Pi (8% in NaHCÜ3 and 13% in NaOH-EDTA extracts) compared with that of uninoculated manure (0.7% in NaHCÜ3 and 0.1% in NaOH-EDTA extracts). However, a greater amount of Pi was released in inoculated manure supplemented with phytate (47% in NaHCÜ3 and 117% in NaOH-EDTA extracts) compared with that of uninoculated manure supplemented with phytate (30% in NaHCÜ3 and 15% in NaOH-EDTA extracts). In addition, the use of denaturing gradient gel electrophoresis (DGGE) and quantitative PCR (qPCR) revealed that the bacterial community structure in manure was affected by inoculation and that the prevalence of Bacillus sp. MQH-19 decreased during incubation (6 days). This study demonstrates that Pi availability in cattle manure can be increased by phytase-producing bacteria inoculation. Phytase-producing bacteria inoculation might represent an attractive strategy to increase P availability in agricultural wastes, which are used as organic fertilizers in crops and pastures

    Causes of death among homeless people: a population-based cross-sectional study of linked hospitalisation and mortality data in England. [version 1; peer review: 2 approved]

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    Background: Homelessness has increased by 165% since 2010 in England, with evidence from many settings that those affected experience high levels of mortality. In this paper we examine the contribution of different causes of death to overall mortality in homeless people recently admitted to hospitals in England with specialist integrated homeless health and care (SIHHC) schemes.  Methods: We undertook an analysis of linked hospital admission records and mortality data for people attending any one of 17 SIHHC schemes between 1st November 2013 and 30th November 2016. Our primary outcome was death, which we analysed in subgroups of 10th version international classification of disease (ICD-10) specific deaths; and deaths from amenable causes. We compared our results to a sample of people living in areas of high social deprivation (IMD5 group). Results: We collected data on 3,882 individual homeless hospital admissions that were linked to 600 deaths. The median age of death was 51.6 years (interquartile range 42.7-60.2) for SIHHC and 71.5 for the IMD5 (60.67-79.0).  The top three underlying causes of death by ICD-10 chapter in the SIHHC group were external causes of death (21.7%; 130/600), cancer (19.0%; 114/600) and digestive disease (19.0%; 114/600).  The percentage of deaths due to an amenable cause after age and sex weighting was 30.2% in the homeless SIHHC group (181/600) compared to 23.0% in the IMD5 group (578/2,512). Conclusion: Nearly one in three homeless deaths were due to causes amenable to timely and effective health care. The high burden of amenable deaths highlights the extreme health harms of homelessness and the need for greater emphasis on prevention of homelessness and early healthcare interventions

    Outcomes of specialist discharge coordination and intermediate care schemes for patients who are homeless: analysis protocol for a population-based historical cohort

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    Introduction People who are homeless often experience poor hospital discharge arrangements, reflecting ongoing care and housing needs. Specialist integrated homeless health and care provision (SIHHC) schemes have been developed and implemented to facilitate the safe and timely discharge of homeless patients from hospital. Our study aims to investigate the health outcomes of patients who were homeless and seen by a selection of SIHHC services. Methods and analysis Our study will employ a historical population-based cohort in England. We will examine health outcomes among three groups of adults: (1) homeless patients seen by specialist discharge schemes during their hospital admission; (2) homeless patients not seen by a specialist scheme and (3)admitted patients who live in deprived neighbourhoods and were not recorded as being homeless. Primary outcomes will be: time from discharge to next hospital inpatient admission; time from discharge to next accident and emergency attendance and 28-day emergency readmission. Outcome data will be generated through linkage to hospital admissions data (Hospital Episode Statistics) and mortality data for November 2013 to November 2016. Multivariable regression will be used to model the relationship between the study comparison groups and each of the outcomes. Ethics and dissemination Approval has been obtained from the National Health Service (NHS) Confidentiality Advisory Group (reference 16/CAG/0021) to undertake this work using unconsented identifiable data. Health Research Authority Research Ethics approval (REC 16/EE/0018) has been obtained in addition to local research and development approvals for data collection at NHS sites. We will feedback the results of our study to our advisory group of people who have lived experience of homelessness and seek their suggestions on ways to improve or take this work further for their benefit. We will disseminate our findings to SIHHC schemes through a series of regional workshops

    Intermediate-linkage steps used to obtain longitudinal data (containing heath service use, morbidity and mortality) for a large cohort of patients who are homeless that visited, and were discharged from hospital in England.

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    Introduction In England, details on hospital admissions and mortality are recorded nationally, but housing status and patients’ hospital discharge arrangements are only recorded locally within discharge services. These data are required to evaluate specialist homeless hospital discharge (HHD) services in England, and can be obtained through linkage within and across sectors. Objectives and Approach We aimed to improve linkage to enable the evaluation of HHD schemes. 16 sites with a scheme were recruited along with a specialist facility that deliver screening and treatment services to homeless hostels (Find\&Treat). Linkage fields including National Health Service number (NHS number), name, gender and birthdate for clinical contacts between November 2013 and November 2016 were collected and linked to national hospital data, Hospital Episodes Statistics (HES). To improve linkage with HES, intermediate-linkage to a gender-names dictionary and a national demographic database (NDD) was performed. Ethics, access permissions were obtained through HRA-REC (REC16/EE/0018) and NHS CAG (16/CAG/0021). Results 47,569 clinical contacts among people who were homeless were collected from Find&Treat and 12,931 from sites. The median age at mid-study period (15th May 2015) among contacts with sites compared to Find&Treat were similar at 44 (IQR 34-53, n=12,905) and 45 (IQR 35-54, n=47,569), respectively. Among Find&Treat, 82% (n=38,905) were contacts with Males and 18% (n=8,650) with Females. Gender was not collected at all HHD sites or for all admissions. 70% of contacts had missing gender and among these contacts, gender was assigned using the gender-names dictionary. After imputing gender, 52% of contacts all linkage fields and 47% had all but NHS number. These data were linked to the NDD, an approximate 60% linkage rate was achieved retrieving complete linkage fields for these contacts. Conclusion/Implications Intermediate linkage steps described here provides the largest dataset of it’s kind, enabling investigations into effectiveness of hospital discharge schemes in England. The study provides generally a proof of concept that large cohorts of hard-to-reach population groups can be obtained through data linkage

    Urochloa ruziziensis cover crop increases the cycling of soil inositol phosphates

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    Ruzigrass (Urochloa ruziziensis) is a cover crop that is commonly used in Brazil and exudes high concentrations of organic acids from its roots, and is therefore expected to mobilize soil organic P such as inositol phosphates. However, it is not known if this can occur only under P deficient conditions. Specifically, we aimed to test the hypothesis that the degradation of inositol phosphates is increased by growing ruzigrass at two different P levels. To investigate this, we studied soil organic P in a 9-year-old field experiment, with treatments consisting of ruzigrass or fallow during the soybean (Glycine max) off-season, with or without P addition. Organic P was extracted in NaOH-EDTA, followed by colorimetric quantification of organic P hydrolysable by phytase, and myo-inositol hexakisphosphate by hypobromite oxidation and HPLC separation. Ruzigrass dry matter yield increased by about 80% with P application. Ruzigrass reduced the concentration of phytase labile P and myo-inositol hexakisphosphate, but only in soil receiving P. A corresponding increase in unidentified inositol phosphates, presumably representing lower-order esters, was also observed after ruzigrass in soil with P application. We deduce that the degradation of inositol phosphates under ruzigrass with P application is due to greater ruzigrass productivity in the more fertile treatment, increasing the release of root exudates that solubilize inositol phosphates and promote their decomposition by phytase. We conclude that ruzigrass cover cropping can promote the cycling of recalcitrant soil organic P, but only when fertility is raised to a sufficient level to ensure a productive crop. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature

    A holistic approach to understanding the desorption of phosphorus in soils

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    The mobility and resupply of inorganic phosphorus (P) from the solid phase were studied in 32 soils from the UK. The combined use of diffusive gradients in thin films (DGT), diffusive equilibration in thin films (DET) and the “DGT-induced fluxes in sediments” model (DIFS) were adapted to explore the basic principles of solid-to-solution P desorption kinetics in previously unattainable detail. On average across soil types, the response time (Tc) was 3.6 h, the desorption rate constant (k–1) was 0.0046 h–1, and the desorption rate was 4.71 nmol l–1 s–1. While the relative DGT-induced inorganic P flux responses in the first hour is mainly a function of soil water retention and % Corg, at longer times it is a function of the P resupply from the soil solid phase. Desorption rates and resupply from solid phase were fundamentally influenced by P status as reflected by their high correlation with P concentration in FeO strips, Olsen, NaOH–EDTA and water extracts. Soil pH and particle size distribution showed no significant correlation with the evaluated mobility and resupply parameters. The DGT and DET techniques, along with the DIFS model, were considered accurate and practical tools for studying parameters related to soil P desorption kinetics

    Can tropical grasses grown as cover crops improve soil phosphorus availability?

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    Tropical grasses grown as cover crops can mobilize phosphorus (P) in soil and have been suggested as a tool to increase soil P cycling and bioavailability. The objective of this study was to evaluate the effect of tropical grasses on soil P dynamics, lability, desorption kinetics and bioavailability to soya bean, specifically to test the hypothesis that introducing grass species in the cropping system may affect soil P availability and soya bean development according to soil P concentration. Three grass species, ruzi grass (Urochloa ruziziensis), palisade grass (Urochloa brizantha) and Guinea grass (Megathyrsus maximus), were grown in soils with contrasting P status. Soya bean was grown after grasses to assess soil P bioavailability. Hedley P fractionation, microbial biomass P, phytase-labile P and the diffusive gradient in thin films were determined, before and after cultivation. It was found that grasses remobilized soil P, reducing the concentration of recalcitrant P forms. The effect of grasses on changing the P desorption kinetics parameters did not directly explain the observed variation on P bioavailability to soya bean. Grasses and microorganisms solubilize recalcitrant organic P (Po) forms and tropical grasses grown as cover crops increased P bioavailability to soya bean mainly due to the supply of P by decomposition of grass residues in low-P soil. However, no clear advantages in soya bean P nutrition were observed when in rotation with these grasses in high-P soil. This study indicates that further advantages in soya bean P nutrition after tropical grasses may be impeded by phytate, which is not readily available to plants. © 2018 British Society of Soil Scienc

    A saga do algodão no semiárido nordestino: histórico, declínio e as perspectivas de base agroecológica

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    O cultivo do algodão no semiárido nordestino remonta ao período colonial no Brasil. Nas épocas áureas de produção, cumpriu importante papel na economia da região semiárida. Inicialmente, as lavouras de algodão localizavam-se próximas aos quintais das casas, destinadas à produção de fibra para as roupas dos escravos, bem como à produção de alimentos quando se associava o algodão com milho e feijão. Mais tarde, o cultivo de algodão se associou também à pecuária, gerando fibra, alimento para os animais e renda para a população local. O algodão teve seu apogeu no semiárido nos idos do século XX, quando ficou conhecido como o “ouro branco do Nordeste”, até o seu declínio a partir dos anos 1980. No entanto, a partir do início do século XXI, iniciou-se um lento e progressivo processo de recuperação, agora em bases agroecológicas vinculadas à agricultura familiar e ao mercado de moda em nível mundial, com interesse crescente na fibra de algodão orgânica. Alguns aspectos que desafiaram a produção de algodão no passado ainda continuam instigando agricultores e agricultoras no presente. E é precisamente sobre estes aspectos que a revisão proposta nesse artigo visa tratar. Foram trazidos aqui autores clássicos e contemporâneos, além de algumas entrevistas com pessoas-chave envolvidas na retomada do algodão. O objetivo é fazer aflorar a multidimensionalidade da saga do algodão no semiárido nordestino, considerando-se as suas bases históricas, técnicas, sociológicas e mercadológicas para apontar caminhos que poderão contribuir com sua sustentabilidade futura.The cotton has been cultivated in the northeastern semiarid region in Brazil since the colonial period. In the golden age of production, it played an important role in the economy of the semiarid region. Initially, cotton crops were located close to the backyards of the houses, mainly intended for producing fiber for the slave's clothing, as well as for the production of food when it was combined with corn and beans. Later on, cotton cultivation was also associated with livestock, generating fiber, food for animals and income for the local population. Cotton reached its peak during the 20th century, when it became known as the “white gold of the Northeast”, until its decline in the 1980s. However, from the beginning of the 21st century, it started a slow and progressive recovery process, now on an agroecological basis, linked to small farmers and the fashion market worldwide, with growing interest in organic cotton fiber. Some aspects that have challenged the cotton production in the past still continue to challenge farmers today. It is precisely on these aspects that this review aims to address. Classic and contemporary authors were brought here, as well as some interviews with key-people involved in the recent experiences with cotton. The objective is to bring out the multidimensionality of the cotton saga in the northeastern semiarid, considering its historical, technical, sociological and marketing aspects to point out ways that may contribute to its future sustainability

    P and Ca digestibility is increased in broiler diets supplemented with the high-phytase HIGHPHY wheat

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    Around 70% of total seed phosphorus is represented by phytate which must be hydrolysed to be bioavailable in non-ruminant diets. The limited endogenous phytase activity in non-ruminant animals make it common practice to add an exogenous phytase source to most poultry and pig feeds. The mature grain phytase activity (MGPA) of cereal seeds provides a route for the seeds themselves to contribute to phytate digestion, but MGPA varies considerably between species and most varieties in current use make negligible contributions. Currently, all phytases used for feed supplementation and transgenic improvement of MGPA are derived from microbial enzymes belonging to the group of histidine acid phosphatases (HAP). Cereals contain HAP phytases, but the bulk of MGPA can be attributed to phytases belonging to a completely different group of phosphatases, the purple acid phosphatases (PAPhy). In recent years, increased MGPAs were achieved in cisgenic barley holding extra copies of barley PAPhy and in the wheat HIGHPHY mutant, where MGPA was increased to ~6200 FTU/kg. In the present study, the effect of replacing 33%, 66% and 100% of a standard wheat with HIGHPHY wheat was compared with a control diet with and without 500 FTU of supplemental phytase. Diets were compared by evaluating broiler performance, ileal Ca and P digestibility and tibia development, using nine replicate pens of four birds per diet over 3 weeks from hatch. There were no differences between treatments in any tibia or bird performance parameters, indicating the control diet did not contain sufficiently low levels of phosphorus to distinguish effect of phytase addition. However, in a comparison of the two wheats, the ileal Ca and P digestibility coefficients for the 100% HIGHPHY wheat diets are 22.9% and 35.6% higher, respectively, than for the control diet, indicating the wheat PAPhy is functional in the broiler digestive tract. Furthermore, 33% HIGHPHY replacement of conventional wheat, significantly improved Ca and P digestibility over the diet-supplemented exogenous phytase, probably due to the higher phytase activity in the HIGHPHY diet (1804 v. 1150 FTU). Full replacement by HIGHPHY gave 14.6% and 22.8% higher ileal digestibility coefficients for Ca and P, respectively, than for feed supplemented with exogenous HAP phytase at 500 FTU. This indicates that in planta wheat PAPhys has promising potential for improving P and mineral digestibility in animal feed
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