U.S. science policy. Leaving Congress, physicist Bill Foster calls for reinforcements     

Kintisch E 《Science (New York, N.Y.)》2010,330(6011):1601

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Detachment of sprayed colloidal copper oxychloride–metalaxyl fungicides by a shallow water flow     

Eva Pose‐Juan  Marcos Paradelo‐Pérez  Raquel Rial‐Otero  Jesus Simal‐Gándara  José E López‐Periago 《Pest management science》2009,65(6):615-623

BACKGROUND: Flow shear stress induced by rainfall promotes the loss of the pesticides sprayed on crops. Some of the factors influencing the losses of colloidal‐size particulate fungicides are quantified by using a rotating shear system model. With this device it was possible to analyse the flow shear influencing washoff of a commercial fungicide formulation based on a copper oxychloride–metalaxyl mixture that was sprayed on a polypropylene surface. A factor plan with four variables, i.e. water speed and volume (both variables determining flow boundary stress in the shear device), formulation dosage and drying temperature, was set up to monitor colloid detachment. RESULTS: This experimental design, together with sorption experiments of metalaxyl on copper oxychloride, and the study of the dynamics of metalaxyl and copper oxychloride washoff, made it possible to prove that metalaxyl washoff from a polypropylene surface is controlled by transport in solution, whereas that of copper oxychloride occurs by particle detachment and transport of particles. Average losses for metalaxyl and copper oxychloride were, respectively, 29 and 50% of the quantity applied at the usual recommended dosage for crops. CONCLUSION: The key factors affecting losses were flow shear and the applied dosage. Empirical models using these factors provided good estimates of the percentage of fungicide loss. From the factor analysis, the main mechanism for metalaxyl loss induced by a shallow water flow is solubilisation, whereas copper loss is controlled by erosion of copper oxychloride particles. Copyright © 2009 Society of Chemical Industry  相似文献   

BLUP for genetic evaluation of plants in non-inbred families of annual crops     

José Marcelo Soriano Viana  Ísis Fernanda de Almeida  Marcos Deon Vilela de Resende  Vinícius Ribeiro Faria  Fabyano Fonseca e Silva 《Euphytica》2010,174(1):31-39

Best Linear Unbiased Prediction (BLUP) has become the most widely used method for genetic assessment of animal and perennial species, and it is potentially relevant for annual crops. The objective of this study was to assess this method for selection within non-inbred families in recurrent breeding programs. The ‘animal model’ was fitted. The data were expansion volume (EV) and grain yield of plants in recombination plots of two to three selection cycles in the popcorn population Viçosa, with half- and full-sib progenies. The ASReml program was used to perform the analyses. For both EV and yield the breeding values predicted from the additive and additive-dominant models were highly correlated. Multi-generation BLUP was, in general, more accurate than single-generation analysis. These two methods resulted in highly correlated predicted breeding values. The dominance genetic values predicted from the single- and multi-generation analysis were also highly correlated. The pedigree information reduced the percentage of coincidences among the selected individuals relative to phenotypic selection mainly in the population structured in half-sib families. Based on breeding values predicted by BLUP analysis, the most efficient selection procedure was mass selection.  相似文献   

Water yam (Dioscorea alata L.) development as affected by photoperiod and temperature: Experiment and modeling     

J. Marcos  A. Lacointe  R. Tournebize  R. Bonhomme  J. Sierra 《Field Crops Research》2009

Water yam (Dioscorea alata L.) is one of the most popular tuber crops in the tropics. Although it is well known that photoperiod greatly affects yam development, little information is available on the effect of temperature on different developmental phases, and there has been no attempt to model the effect of both environmental factors. The aim of this study was to assess the combined effect of photoperiod and temperature on the development of two early maturing varieties of yam with similar growth pattern. For this we used a model proposed for potatoes grown under tropical conditions. Experimental information was obtained from 15 field experiments carried out in Guadeloupe (French West Indies) covering a wide range of planting dates. Two yam phases were analyzed: from emergence (EM) to tuber initiation (TI), and from TI to harvest (HA). The EM–HA period varied from 3 to 6 months, with the longer cycles corresponding to early planting dates (e.g. April). On average, EM–TI represented one-third of the EM–HA period, and was mainly affected by photoperiod and to a lesser extent by temperature. Both factors also affected the duration of TI–HA but their effects were less noticeable. The observed mean temperature during TI–HA was near the estimated optimum and its effect was less than that of photoperiod. The variation of the phase duration was higher for EM–TI (CV 45%) than for TI–HA (8%), which was satisfactorily explained by the model. For EM–TI there was a positive interaction between both environmental factors which, together with the greater influence of climatic conditions, resulted in much variability in its duration. For TI–HA, a small influence of environmental factors, coupled with a compensatory effect between environmental factors, resulted in a relatively smaller variation in the duration of this phase. The model estimated satisfactorily the dates and the duration of each phase. The root mean square error (RMSE) was 7.4 d which corresponded to 13% and 7% of the observed mean duration of EM–TI and TI–HA, respectively. Our results showed that small changes in photoperiod and temperature, which are very usual in the tropics, have a big effect on the tested yam varieties. We also showed that the model applied in this study can be a useful tool to predict yam development for management purposes as well as for the modeling of yam growth.  相似文献   

Species diversity,population structure and regeneration of woody species in fallows and mature stands of tropical woodlands of southeast Angola   总被引：1，自引：0，他引：1  

Francisco M. P. Gonçalves  Rasmus Revermann  Manuel J. Cachissapa  Amândio L. Gomes  Marcos P. M. Aidar 《林业研究》2018,29(6):1569-1579

This study in the dry tropical woodlands of SE Angola in Cuando-Cubango Province assessed the diversity and composition of woody species in fallows compared to those in mature woodlands. We assessed the population structure of the most harvested woody species by calculating size class distribution and evaluated their regeneration potential based on the density of saplings. The vegetation was surveyed in 20 plots of 20 × 50 m(1000 m2). In each plot, we measured the diameter at breast height(DBH) of all woody species with DBH ≥ 5 cm. The saplings were counted, identified and recorded; 718 individuals, corresponding to 34 species in 32 genera and 15 families were recorded. The size class distribution of target woody species showed three different patterns in fallows and mature woodlands. In general,most of the smaller diameter classes had more individuals than the larger ones did, showing that the regeneration may take place. However, in some diameter classes, the absence of larger stems indicated selective logging of larger trees. Few saplings were recorded in the fallows or mature woodlands; fire frequency and intensity is probably the main obstacle for seed germination and seedling survival rates in the studied area.  相似文献   

How local stakeholders perceive agroforestry systems: an Italian perspective   总被引：1，自引：1，他引：0  

Francesca Camilli  Andrea Pisanelli  Giovanna Seddaiu  Antonello Franca  Valerio Bondesan  Adolfo Rosati  Gerardo Marcos Moreno  Anastasia Pantera  John E. Hermansen  Paul J. Burgess 《Agroforestry Systems》2018,92(4):849-862

This paper reports the results of a study conducted in Italy, within the AGFORWARD (2014–2017) project, aimed at promoting innovative agroforestry practices in Europe. Agroforestry offers a means for maintaining food production whilst addressing some of the negative environmental effects of intensive agriculture. This study aims to elicit the positive and negative points of view and perceptions of local stakeholders in Italy in relation to three types of agroforestry systems. The Participatory Research and Network Development was implemented in three workshops conducted in Sardinia, Umbria, and Veneto regions, and applied adopting a common methodological protocol. Qualitative data were obtained using open discussions with stakeholders on key issues, challenges and innovations. Quantitative data were obtained from stakeholders completing questionnaires during the workshops. A statistical analysis was applied to elicit the differences in stakeholders’ positive and negative perceptions in relation to production, management, environment and socio-economy aspects. Although the participants in the study came from different geographical and socioeconomic contexts with varied educational and cultural backgrounds, the different professional groups (farmers, policy-makers and researchers) and the three workshops generally shared similar perceptions of the benefits and constraints. The effects of agroforestry on production and the environment were generally perceived as positive, whilst those related to management were generally negative. The process of bringing the groups together seemed to be an effective means for identifying the key research gaps that need to be addressed in order to promote the uptake and maintenance of agroforestry.  相似文献   

Effect of reproductive methods and GnRH administration on long-term protocol in Santa Ines ewes     

Biehl  Marcos V  Ferraz Junior  Marcos V C  Ferreira  Evandro M  Polizel  Daniel M  Miszura  Alexandre A  Barroso  José P R  Oliveira  Gabriela B  Bertoloni  Analisa V  Pires  Alexandre V 《Tropical animal health and production》2017,49(6):1303-1308

This study aimed to determine whether reproductive performance of ewes submitted to laparoscopic timed artificial insemination (TAI) would be similar to ante meridiem (AM)/post meridiem (PM) rule and assisted natural mating (NM), and whether GnRH may enhance the pregnancy rate in TAI. In experiment I, 191 non-lactating ewes were synchronized, then TAI was performed either 48 h after progesterone (P4) removal (TAI-48 h) or 12 h after estrus detection (AM/PM); moreover, some ewes were submitted to NM (NM) as control treatment. In experiment II, 247 non-lactating ewes were allocated in five treatments, a control (no-GnRH on protocol) and four treatments arranged in a factorial design 2 × 2. The factors were time and dose of GnRH: ewes that received either 10 μg (TAI-10 μg-36 h) or 25 μg of GnRH (TAI-25 μg-36 h) 36 h after P4 removal and ewes that received either 10 μg (TAI-10 μg-48 h) or 25 μg of GnRH (TAI-25 μg-48 h) at time of insemination, 48 h after P4 removal. In experiment I, pregnancy rate in TAI-48 h was lower (P = 0.03) than AM/PM and NM. Moreover, the probability of pregnancy in TAI-48 h was higher (P = 0.06) in ewes detected in estrus early. In experiment II, the use of GnRH in TAI protocols increased (P < 0.01) pregnancy rate at synchronization, and TAI-25 μ-48 h and TAI-10 μg-36 h treatments increased (P = 0.02) pregnancy rate compered to TAI-10 μg-48 h. We conclude that TAI decreased pregnancy rate compered to NM and AM/PM, which may be improved by GnRH use in TAI to synchronize ovulation.

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Association of SNP variants of MHC Class II DRB gene with thermo-physiological traits in tropical goats     

Abdulmojeed Yakubu  Adebowale E. Salako  Marcos De Donato  Sunday O. Peters  Michael I. Takeet  Mathew Wheto  Moses Okpeku  Ikhide G. Imumorin 《Tropical animal health and production》2017,49(2):323-336

Host defense in vertebrates depend on many secreted regulatory proteins such as major histocompatibility complex (MHC) class II which provide important regulatory and effector functions of T cells. Gene polymorphism in the second exon of Capra-DRB gene in three major Nigerian goat breeds [West African Dwarf (WAD), Red Sokoto (RS), and Sahel (SH)] was analyzed by restriction fragment length polymorphisms (RFLP). Four restriction enzymes, BsaHI, AluI, HaeIII, and SacII, were utilized. The association between the polymorphic sites and some heat tolerance traits were also investigated in a total of 70 WAD, 90 RS, and 50 SH goats. Fourteen different types of alleles identified in the Nigerian goats, four of which were found in the peptide coding region (A57G, Q89R, G104D, and T112I), indicate a high degree of polymorphism at the DRB locus in this species. An obvious excess (P?<?0.01) of non-synonymous substitutions than synonymous (dN/dS) in this locus is a reflection of adaptive evolution and positive selection. The phylogenetic trees revealed largely species-wise clustering in DRB gene. BsaHI, AluI, HaeIII, and SacII genotype frequencies were in Hardy-Weinberg equilibrium (P?>?0.05), except AluI in RS goats and HaeIII in WAD goats (P?<?0.05). The expected heterozygosity (H), which is a measure of gene diversity in the goat populations, ranged from 0.16 to 0.50. Genotypes AA (BsaHI), GG, GC and CC (AluI) and GG, GA, AA (HaeIII) appeared better in terms of heat tolerance. The heat-tolerant ability of SH and RS goats to the hot and humid tropical environment of Nigeria seemed better than that of the WAD goats. Sex effect (P?<?0.05) was mainly on pulse rate and heat stress index, while there were varying interaction effects on heat tolerance. Variation at the DRB locus may prove to be important in possible selection and breeding for genetic resistance to heat stress in the tropics.  相似文献   

Bruises in beef cattle at slaughter in Mexico: implications on quality,safety and shelf life of the meat     

Rosy G. Cruz-Monterrosa  Verónica Reséndiz-Cruz  Armando A. Rayas-Amor  Marcos López  Genaro C. Miranda-de la Lama 《Tropical animal health and production》2017,49(1):145-152

In emergent economies and developing countries of Africa, Asia and Latin America, the major cause for carcass rejection from the international market is bruising; nevertheless, many of these carcases are destined to local markets and meat processing industries for human consumption. Therefore, the aim of the present study was to assess the effect of bruised meat on pH, microbiologic count and biogenic amine (BA) profiles along 21 days of ageing (sampling 1st, 7th, 14th and 21st day) with two packaging method (plastic bag vs vacuum) at 4 °C. A total of 50 bruised carcasses were sampled from 1000 young bulls (Brown Swiss X Zebu) of 18–24 months old and an average live weight of 450?±?66 kg. The results showed significant differences between packaging systems and bruised vs non-bruised meat. The bruised meat caused higher biogenic amine concentrations than did non-bruised meat. We conclude that bruised meat favoured increments of biogenic amine concentrations, even more than did non-bruised meat. The plastic bag?+?vacuum system limited the increments of BA concentration during storage time therefore it improved shelf life of meat. These results emphasized the importance of implementing best management practices during pre-slaughter operations of cattle in order to reduce a possible risk factor for bruised meat.  相似文献   

Radius and ulna fracture repair with the IMEX miniature circular external skeletal fixation system in 37 small and toy breed dogs: A retrospective study          下载免费PDF全文

Denise Bierens DVM  Marcos D. Unis DVM  MS  DACVS  Sady Y. Cabrera DVM  DACVS  Philip H. Kass DVM  PhD  DACVPM  Tina J. Owen DVM  DACVS  Maureen G. Mueller DVM  DACVS 《Veterinary surgery : VS》2017,46(4):587-595

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