333 research outputs found

    Genetic Changes Over Breeding Generations of \u3cem\u3eFestulolium\u3c/em\u3e

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    Festulolium hybrids are a valuable breeding source for tolerance to abiotic stress and to make grass more persistent under drought and in cold environments. In 2004, the EU Commission enlarged the definition of Festulolium which may now include all hybrids between Lolium sp. and Festuca sp. and not only those between L. multiflorum and F. pratensis. We here report allele frequencies at two unlinked PCR-based marker loci in populations derived from tetraploid (2n=4x=28) L. multiflorum x F. glaucescens hybrids where breeding history enables us to test the effects of selection vs that of genetic drift

    QTL mapping of carrot resistance to leaf blight with connected populations: stability across years and consequences for breeding

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    Combining biparental and multiparental connected population analyses was useful for the identification of 11 QTLs in two new genetic backgrounds of carrot resistance to Alternaria dauci and for breeding recommendations. Leaf blight due to the fungus Alternaria dauci is the major carrot foliar disease worldwide. Some resistance QTLs have been previously identified in one population, but the evaluation of additional genetic backgrounds with higher level of resistance would give opportunities for breeders to combine them by pyramiding. For this purpose, two segregating populations were evaluated twice across 4 years in the same environment (1) to compare the efficiency of the single vs. the connected populations approach for characterizing the new sources of carrot resistance to Alternaria dauci; (2) to evaluate the stability of QTLs over the years; and (3) to give recommendations to breeders for marker-assisted selection. Single and connected analyses were complementary; their combination allowed the detection of 11 QTLs. Connected analyses allowed the identification of common and specific QTLs among the two populations and the most favorable allele at each QTL. Important contrasts between allelic effects were observed with four and five most favorable alleles coming from the two resistant parental lines, whereas two other favorable alleles came from the susceptible parental line. While four QTLs were consistent across years, seven were detected within a single year. The heritabilities for both populations PC2 and PC3 were high (75 and 78 %, respectively), suggesting that the resistance of carrot to A. dauci was little affected by these environmental conditions, but the instability of QTL over years may be due to changing environmental conditions. The complementarity between these parental lines in terms of interesting allelic combinations is also discussed

    Retrieval of ozone profiles from GOMOS limb scattered measurements

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    The GOMOS (Global Ozone Monitoring by Occultation of Stars) instrument on board the Envisat satellite measures the vertical composition of the atmosphere using the stellar occultation technique. While the night-time occultations of GOMOS have been proven to be of good quality, the daytime occultations are more challenging due to weaker signal-to-noise ratio. During daytime GOMOS measures limb scattered solar radiation in addition to stellar radiation. In this paper we introduce a retrieval method that determines ozone profiles between 20–60 km from GOMOS limb scattered solar radiances. GOMOS observations contain a considerable amount of stray light at high altitudes. We introduce a method for removing stray light and demonstrate its feasibility by comparing the corrected radiances against those measured by the OSIRIS (Optical Spectrograph & Infra Red Imaging System) instrument. For the retrieval of ozone profiles, a standard onion peeling method is used. The first comparisons with other data sets suggest that the retrieved ozone profiles in 22–50 km are within 10% compared with the GOMOS night-time occultations and within 15% compared with OSIRIS. GOMOS has measured about 350 000 daytime profiles since 2002. The retrieval method presented here makes this large amount of data available for scientific use

    Short-Term Thermal Acclimation Modifies the Metabolic Condition of the Coral Holobiont

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    The nutritional symbiosis between coral hosts and photosynthetic dinoflagellates is fundamental to the functioning of coral reefs. Rising seawater temperatures destabilize this relationship, resulting in drastic declines in world-wide coral cover. Thermal history is thought to play an important role in shaping a coral\u27s response to subsequent thermal stress. Here, we exposed Pocillopora damicornis to two thermal acclimation regimes (ambient vs. warm) and compared the effect that acclimation had on the coral holobiont\u27s response to a subsequent seven day heat stress event. We conducted daily physiological measurements at the holobiont level (gross photosynthesis, respiration, host protein content, symbiont density and chlorophyll content) throughout the heating event, as well as cellular-level imaging of 13C-bicarbonate and 15N-nitrate assimilation (using NanoSIMS) at the end of the heat stress event. Thermal acclimation history had a negligible effect on the measurements conducted at the holobiont level during the heat stress event. No differences were observed in the O2-budget between ambient and warm-acclimated corals and only small fluctuations in host protein, symbiont density and chlorophyll content were detected. In contrast, this lack of differential response, was not mirrored at the cellular level. Warm-acclimated corals had substantially higher 13C enrichment in the host gastrodermis and lipid bodies, but significantly lower 15N-nitrate assimilation in the symbionts and the host tissue layers, relative to the ambient-acclimated corals. We discuss potential reasons for the disconnect that occurred between symbiont bicarbonate and nitrate assimilation (in the absence of photosynthetic breakdown) in the warm-acclimated corals. We suggest this represents either a shift in nitrogen utilization, or supply limitation by the host. Our findings raise several interesting hypotheses regarding the role that nitrogen metabolism plays in thermal stress, which will warrant further investigation if we are to understand the acclimatization capacity of the coral holobiont

    A global climatology of the mesospheric sodium layerfrom GOMOS data during the 2002-2008 period

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    This paper presents a climatology of the mesospheric sodium layer built from the processing of 7 years of GOMOS data. With respect to preliminary results already published for the year 2003, a more careful analysis was applied to the averaging of occultations inside the climatological bins (10° in latitude-1 month). Also, the slant path absorption lines of the Na doublet around 589 nm shows evidence of partial saturation that was responsible for an underestimation of the Na concentration in our previous results. The sodium climatology has been validated with respect to the Fort Collins lidar measurements and, to a lesser extent, to the OSIRIS 2003–2004 data. Despite the important natural sodium variability, we have shown that the Na vertical column has a marked semi-annual oscillation at low latitudes that merges into an annual oscillation in the polar regions, a spatial distribution pattern that was unreported so far. The sodium layer seems to be clearly influenced by the mesospheric global circulation and the altitude of the layer shows clear signs of subsidence during polar winter. The climatology has been parameterized by time-latitude robust fits to allow for easy use. Taking into account the non-linearity of the transmittance due to partial saturation, an experimental approach is proposed to derive mesospheric temperatures from limb remote sounding measurements

    Integration of HIV/AIDS services into African primary health care: lessons learned for health system strengthening in Mozambique - a case study

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    <p>Abstract</p> <p>Introduction</p> <p>In 2004, Mozambique, supported by large increases in international disease-specific funding, initiated a national rapid scale-up of antiretroviral treatment (ART) and HIV care through a vertical "Day Hospital" approach. Though this model showed substantial increases in people receiving treatment, it diverted scarce resources away from the primary health care (PHC) system. In 2005, the Ministry of Health (MOH) began an effort to use HIV/AIDS treatment and care resources as a means to strengthen their PHC system. The MOH worked closely with a number of NGOs to integrate HIV programs more effectively into existing public-sector PHC services.</p> <p>Case Description</p> <p>In 2005, the Ministry of Health and Health Alliance International initiated an effort in two provinces to integrate ART into the existing primary health care system through health units distributed across 23 districts. Integration included: a) placing ART services in existing units; b) retraining existing workers; c) strengthening laboratories, testing, and referral linkages; e) expanding testing in TB wards; f) integrating HIV and antenatal services; and g) improving district-level management. Discussion: By 2008, treatment was available in nearly 67 health facilities in 23 districts. Nearly 30,000 adults were on ART. Over 80,000 enrolled in the HIV/AIDS program. Loss to follow-up from antenatal and TB testing to ART services has declined from 70% to less than 10% in many integrated sites. Average time from HIV testing to ART initiation is significantly faster and adherence to ART is better in smaller peripheral clinics than in vertical day hospitals. Integration has also improved other non-HIV aspects of primary health care.</p> <p>Conclusion</p> <p>The integration approach enables the public sector PHC system to test more patients for HIV, place more patients on ART more quickly and efficiently, reduce loss-to-follow-up, and achieve greater geographic HIV care coverage compared to the vertical model. Through the integration process, HIV resources have been used to rehabilitate PHC infrastructure (including laboratories and pharmacies), strengthen supervision, fill workforce gaps, and improve patient flow between services and facilities in ways that can benefit all programs. Using aid resources to integrate and better link HIV care with existing services can strengthen wider PHC systems.</p

    Orexinergic Input to Dopaminergic Neurons of the Human Ventral Tegmental Area

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    The mesolimbic reward pathway arising from dopaminergic (DA) neurons of the ventral tegmental area (VTA) has been strongly implicated in reward processing and drug abuse. In rodents, behaviors associated with this projection are profoundly influenced by an orexinergic input from the lateral hypothalamus to the VTA. Because the existence and significance of an analogous orexigenic regulatory mechanism acting in the human VTA have been elusive, here we addressed the possibility that orexinergic neurons provide direct input to DA neurons of the human VTA. Dual-label immunohistochemistry was used and orexinergic projections to the VTA and to DA neurons of the neighboring substantia nigra (SN) were analyzed comparatively in adult male humans and rats. Orexin B-immunoreactive (IR) axons apposed to tyrosine hydroxylase (TH)-IR DA and to non-DA neurons were scarce in the VTA and SN of both species. In the VTA, 15.062.8% of TH-IR perikarya in humans and 3.260.3% in rats received orexin B-IR afferent contacts. On average, 0.2460.05 and 0.0560.005 orexinergic appositions per TH-IR perikaryon were detected in humans and rats, respectively. The majority(86–88%) of randomly encountered orexinergic contacts targeted the dendritic compartment of DA neurons. Finally, DA neurons of the SN also received orexinergic innervation in both species. Based on the observation of five times heavierorexinergic input to TH-IR neurons of the human, compared with the rat, VTA, we propose that orexinergic mechanism acting in the VTA may play just as important roles in reward processing and drug abuse in humans, as already established well in rodents
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