789 research outputs found

    Microbial community structure under various wheat-based cropping systems

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    Non-Peer ReviewedThe effects of cropping systems on soil biological quality are slow to develop. We sampled the soil of a 36-year old long-term experiment established on an Orthic Brown Chernozem, at Swift Current SK, in the fall of 2003, to define the long-term impact of 10 cropping systems on soil biological quality. Numerous variables related to soil function - soil pH, organic C (SOC), moisture, enzymatic activities, available N, P, and S - and soil community structure - phospholipid fatty acids (PLFA) indicators of fungal saprobes, arbuscular mycorrhizal fungi and bacterial groups - were used to describe soil quality. Soils under different cropping systems had become distinct, as revealed by discriminant analyses. Variations in SOC, and pH were most influential in discriminating the soils. SOC varied from 2.38% under continuous wheat to 1.81% under a fallow-wheat rotation. pH went from 6.55 under fallow-wheat-wheat receiving no P-fertilizer, to 4.89, under chemical fallow – fall rye – wheat. Absence of fallow under normal fertilization increased SOC and decreased soil pH. Variations in SOC and pH were concurrent with variations in microbial community structure. Enhanced AM fungi abundance under low soil P, could compensate for the large soil P depletion created by 36 years without P fertilizer, in a fallow-wheat-wheat rotation, and P-fertilized and non-P-fertilized plots produced similar yields. The season of 2003 was dryer than normal and it remains to be seen if AM fungi can compensate for low soil available P when soil moisture is abundant

    Seasonal variation in the soil microbial community in wheat-growing soil and influence of C, N, and P inputs

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    Non-Peer ReviewedIt has long been know that N and P fertilization increases plant growth and yield, but the impact of fertilization on soil microorganisms has rarely been considered. Long-term plots (36-year old) under fallow-wheat-wheat (F-W-W) rotations with no P or no N fertilization, or normally fertilized, and plots receiving low C inputs due to frequent fallow (F-W rotation) were used to define the impact of C, N and P on the seasonal variation of the soil microbial communities in the fallow-after-wheat or the wheat-after-fallow phases of the rotations. The soil was sampled on June 8, July 4, August 5 and September 16, in 2003. There was no significant (P≤ 0.05) time by treatment interactions. Populations of bacteria, arbuscular mycorrhizal (AM) fungi and saprophytic fungi, as estimated by phospholipids fatty acid (PLFA) indicators, were strongly reduced on July 4th, a date corresponding to rapid plant growth. Sporulation of fungal saprobes was enhanced at that date, as indicated by the neutral lipid fatty acid (NLFA) to PLFA fraction ratio of the fatty acid C18:2. It appears that a competition for resources exists between soil microorganisms and wheat, at least in July at the time of active crop growth. While P availability had little effect on soil microorganisms, absence of N fertilization increased sporulation in AM and saprophytic fungi. In spite of the biotrophic1 nature of AM fungi, C input in the form of infrequent fallow or presence of living wheat plant favoured the partitioning of fatty acids into reserve lipid i.e., NLFA

    Differentiation of type A foot-and-mouth disease virus subtypes by double-and radial-immunodiffusion analysis.

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    Para clasificar el virus de la enfermedad de las patas y boca del ganado y reconocer el subtipo, se examinaron cuatro subtipos del virus FMDV (Foot and Mouth Disease Virus) así: A-12, A-24, A-31 y A-32. Si la identidad parcial se obtiene bajo condiciones de campo se indica un nuevo subtipo y deberá ser examinado en mayor detalle. La aplicabilidad de la técnica convencional de inmunodifusión radial para diferenciar subtipos de FMDV fue examinada y probada con antisueros por cada cuatro subtipos de virus para reacciones homólogas y heterogamas. Fueron evidentes las diferencias en apariencia de los anillos formados en el precipitado por sistemas homólogos y heterogamos. Los estimativos de la cantidad de anticuerpos precipitados por estos sistemas, se determinaron asumiendo un valor común (anillo-ración masa), la cual representa la masa inicial de anticuerpo dentro del anillo para la masa de antígenos usados en la fuente. Todos los antisueros contienen gran cantidad de anticuerpos que reaccionan con virus homólogos más que con virus heterogamos. Se hizo un rango tentativo antigénico en el cual los subtipos A-31 y A-32 estuvieron a los extremos de la lista de ordenamiento con subtipos A-24 y A-12 en una posición intermedia así: A-31, A-24, A-12 y A-32. Mientras la doble inmunodifusión permite la diferenciación de estos subtipos, el método SRID (Single Radial Inmunodiffusion Determinations) proporciona estimaciones cuantitativa

    Beta vulgaris lines from USDA-ARS Kimberly evaluated for resistance to Cercospora beticola, 2016

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    In 2016, six sugar beet (Beta vulgaris L.) germplasm lines from the USDA-ARS Kimberly program and 2 check lines [EL50/2 (resistant) and F1042 (susceptible)] were screened for resistance to Cercospora beticola. The Cercospora leaf spot (CLS) evaluation was conducted at the Michigan State University Saginaw Valley Research and Extension Center (SVREC) near Frankenmuth, MI in a field that had been planted in wheat with clover underseeded in 2015. The germplasm was planted on 6 May and thinned by hand as necessary. Single-row plots 4.5 m long with 51 cm between row spacing were planted with the treatments arranged in a randomized complete block design with four replications. Quadris 2.08SC (azoxystrobin) was applied at 0.0091 kg/100 m row in a 14 cm band in-furrow at planting to control Rhizoctonia damping-off. Weeds were controlled by a preplant application of ethofumesate 9 May, four times with mixtures of phenmedipham, desmedipham, triflusulfuron methyl, and clopyralid (18 and 23 May, 10 Jun., and 21 Jun), and once with S-metolachlor (29 Jun). The herbicide spray treatments had to also be supplemented with hand weeding. The nursery was spray inoculated on 5 Jul. with a liquid spore suspension (1 x 103 spores/ml) of C. beticola. The inoculum was produced from a mixture of leaves collected from the 2015 CLS nursery at SVREC and from naturally infected sugar beets grown at SVREC and on the Michigan State University campus farms in East Lansing, MI. The plots were rated for foliar symptom development on 6 Sep. using a scale of 0 to 10 (0 = healthy and 10 = all leaves dead; J. Am. Soc. Sugar Technol. 16:284). Data were rank transformed prior to analysis in SAS (Ver. 9.4) with mixed linear models (Proc MIXED), but the non-transformed means have been presented in the table. Mean separation was based on a PDIFF comparison with a probability cutoff of 0.05. Cercospora leaf spot development was uniform and moderate and other disease and pest problems were evident in the plot area. The checks performed as expected for the visual rating. Statistically, five of the entries contain at least moderate resistance since their visual ratings were at least as good as the moderate and resistant checks. However, entry 3 was better than the resistant check and entries 4, 5, and 6 were equal to the resistant check. These data confirm what had been determined the previous year, so these lines will be incorporated into the USDA-ARS germplasm improvement program as a source of resistance to CLS

    Beta vulgaris lines from USDA-ARS Kimberly evaluated for resistance to Cercospora beticola, 2015.

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    In 2015, six sugar beet (Beta vulgaris L.) germplasm lines from the USDA-ARS Kimberly program and 2 check lines [EL50/2 (resistant) and F1042 (susceptible)] were screened for resistance to Cercospora beticola. The Cercospora leaf spot (CLS) evaluation was conducted at the Michigan State University Saginaw Valley Research and Extension Center (SVREC) near Frankenmuth, MI in a field that had been planted in wheat with clover underseeded in 2014. The germplasm was planted on 30 Apr. and thinned by hand as necessary. Single-row plots 4.5 m long with 51 cm between row spacing were planted with the treatments arranged in a randomized complete block design with three replications. Quadris 2.08SC (azoxystrobin) was applied at 0.0091 kg/100 m row in a 14 cm band in-furrow at planting to control Rhizoctonia damping-off. Weeds were controlled by a preplant application of ethofumesate (7 May), three times with mixtures of phenmedipham, desmedipham, triflusulfuron methyl, and clopyralid (23 May, 11 Jun., and 24 Jun), and once with S-metolachlor (17 Jun.). The herbicide spray treatments had to also be supplemented with hand weeding. The nursery was spray inoculated on 2 Jul with a liquid spore suspension (1 x 103 spores/ml) of C. beticola. The inoculum was produced from a mixture of leaves collected from the 2014 CLS nursery at SVREC and from naturally infected sugar beets grown at SVREC and on the Michigan State University campus farms in East Lansing, MI. The plots were rated for foliar symptom development on 9 Sep. using a scale of 0 to 10 (0 = healthy and 10 = all leaves dead; J. Am. Soc. Sugar Technol. 16:284). Data were rank transformed prior to analysis in SAS (Ver. 9.4) with mixed linear models (Proc MIXED), but the non-transformed means have been presented in the table. Mean separation was based on a PDIFF comparison with a probability cutoff of 0.05. Cercospora leaf spot development was uniform and moderate and other disease and pest problems were evident in the plot area. The checks performed as expected for the visual rating. Statistically, five of the entries contain at least moderate resistance since their visual ratings were at least as good as the moderate and resistant checks. However, 3 entries (4, 5, and 6) were better than the resistant check and entry 3 was equal to the resistant check. If the resistance in these four entries can be confirmed, these lines will be considered for incorporation into the USDA-ARS germplasm improvement program as a source of resistance to CLS

    Virulence, Distribution and Diversity of Rhizoctonia Solani from Sugar Beet in Idaho and Oregon

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    Rhizoctonia root rot causes serious losses on sugar beet worldwide. In order to help explain why Rhizoctonia root rot management practices have not performed well in some areas of the Intermountain West (IMW), a survey was conducted. In the IMW from 2004 to 2006, 94 Rhizoctonia solani field isolates were collected from sugar beet roots. These field isolates were compared with 19 reference strains and 46 accessions from GenBank for genetic diversity based on sequencing of the ITS-5.8S rDNA region. Greenhouse pathogenicity tests on sugar beet and silage corn were conducted and plant damage was assessed using a randomized complete block design with at least four replications. The majority (92%) of the isolates had identity with the AG-2-2 IIIB (48%) or AG-4 subgroups (44%). Isolates from AG-2-2 IIIB were the most virulent on sugar beet and had the most diversity in phylogenetic analysis. Seven (all AG-2-2 IIIB) of 18 isolates tested could attack both sugar beet and corn, with two of the isolates causing less root rot than the others. To reduce Rhizoctonia root rot on sugar beet and corn, crop rotations and the isolates utilized for selecting host resistance could be given further consideration

    Photo- and Electron-Production of Mesons on Nucleons and Nuclei

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    In these lectures I will show some results obtained with the chiral unitary approach applied to the photo and electroproduction of mesons. The results for photoproduction of ηπ0p\eta \pi^0 p and K0π0Σ+K^0 \pi^0 \Sigma^+, together with related reactions will be shown, having with common denominator the excitation of the Δ(1700)\Delta(1700) resonance which is one of those dynamically generated in the chiral unitary approach. Then I will show results obtained for the e+e−→ϕf0(980)e^+ e^- \to \phi f_0(980) reaction which reproduce the bulk of the data except for a pronounced peak, giving support to a new mesonic resonance, X(2175). Results will also be shown for the electromagnetic form factors of the N∗(1535)N^*(1535) resonance, also dynamically generated in this approach. Finally, I will show some results on the photoproduction of the ω\omega in nuclei, showing that present experimental results claiming a shift of the ω\omega mass in the medium are tied to a particular choice of background and are not conclusive. One the other hand, the same experimental results show unambiguously a huge increase of the ω\omega width in the nuclear medium.Comment: Lecture at the "International School of Nuclear Physics", 29th Course Quarks in Hadrons and Nuclei, Erice, Italy, September 2007. Note added in Proofs concerning the mixed events technique and other comments on omega productio

    Chronic myelomonocytic leukemia in younger patients : molecular and cytogenetic predictors of survival and treatment outcome

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    In patients with chronic myelomonocytic leukemia (CMML), age>65 years is an adverse prognostic factor. Our objective in the current study was to examine risk factors for survival and treatment outcome in 261 'young' adults with CMML, as defined by age \u2a7d65 years. In multivariable analysis, lower HB (P=0.01), higher circulating blast % (P=0.002), ASXL1 (P=0.0007) and SRSF2 mutations (P=0.008) and Mayo-French cytogenetic stratification (P=0.04) negatively impacted survival. Similarly, leukemia-free survival was independently affected by higher circulating blast % (P<0.0001), higher bone marrow blast % (P=0.0007) and the presence of circulating immature myeloid cells (P=0.0002). Seventy-five (29%) patients received hypomethylating agents (HMA), with the median number of cycles being 5, and the median duration of therapy being 5 months. The over-all response rate was 40% for azacitidine and 30% for decitabine. Fifty-three (24%) patients underwent an allogeneic hematopoietic stem cell transplant (AHSCT), with a response rate of 56% and a non-relapse mortality of 19%. Survival in young adults with CMML, although higher than in older patients, is poor and even worse in the presence of ASXL1 and SRSF2 mutations. Treatment outcome was more impressive with AHSCT than with HMA and neither was influenced by ASXL1/SRSF2 mutations or karyotype

    Planck 2015 results. XXVII. The Second Planck Catalogue of Sunyaev-Zeldovich Sources

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    We present the all-sky Planck catalogue of Sunyaev-Zeldovich (SZ) sources detected from the 29 month full-mission data. The catalogue (PSZ2) is the largest SZ-selected sample of galaxy clusters yet produced and the deepest all-sky catalogue of galaxy clusters. It contains 1653 detections, of which 1203 are confirmed clusters with identified counterparts in external data-sets, and is the first SZ-selected cluster survey containing > 10310^3 confirmed clusters. We present a detailed analysis of the survey selection function in terms of its completeness and statistical reliability, placing a lower limit of 83% on the purity. Using simulations, we find that the Y5R500 estimates are robust to pressure-profile variation and beam systematics, but accurate conversion to Y500 requires. the use of prior information on the cluster extent. We describe the multi-wavelength search for counterparts in ancillary data, which makes use of radio, microwave, infra-red, optical and X-ray data-sets, and which places emphasis on the robustness of the counterpart match. We discuss the physical properties of the new sample and identify a population of low-redshift X-ray under- luminous clusters revealed by SZ selection. These objects appear in optical and SZ surveys with consistent properties for their mass, but are almost absent from ROSAT X-ray selected samples

    Divided communities and contested landscapes: Mobility, development and shifting identities in migrant destination sites in Papua New Guinea

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    Internal conflicts at the local and national levels in several South Pacific countries have revealed the fragility of national unity and the difficulties nations face in governing and managing their own economic development. In Papua New Guinea, the focus of this paper, an uncertain economic future for many rural and urban communities, and rising inequalities in income opportunities and access to resources, have coincided with greater intolerance of migrants at sites of high in-migration by customary landowners and provincial and local authorities. This paper draws on fieldwork undertaken in the major oil palm growing regions of Papua New Guinea where migrants from densely populated regions of the country have settled on state land alienated from customary landowners. We examine how struggles over land, resource control and development are polarising migrant and landowner identities resulting in increasing tensions and episodic communal violence. A settler identity is emerging based on a narrative of nation building and national development, while an ethno-regional identity amongst customary landowners is undermining the citizen rights of migrants and challenging the role and authority of the state in land matters
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