Patchiness in habitat distribution can enhance biological diversity of coastal engineering structures

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High mortality of adult female Magellanic penguins by gillnet fisheries in southern Brazil

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Historical aspects, current status and prospects of pejerrey aquaculture in South America

The pejerrey Odontesthes bonariensis (Valenciennes, 1835) is an inland water fish from the Pampas region comprising part of Argentina, Uruguay and the South of Brazil. Pejerrey is a very popular fish in this region and has a long history of domestic and international introductions, which attests to the high quality and market value of its flesh, as well as its attractiveness as a game fish. The desirable characteristics of pejerrey also make it a good candidate for aquaculture, and the first trials on pejerrey cultivation (atheriniculture) were started more than a century ago in Argentina. In spite of the considerable interest in its development, little progress has been made and atheriniculture is still restricted to propagation and stocking for sport fishing purposes. In this review, we summarize the history of atheriniculture and the biological, technological, scientific, cultural and infrastructural constraints to pejerrey aquaculture development thus far. We also suggest possible scenarios of pejerrey aquaculture development compatible with the socio–economic conditions of South American countries. Our projections also take into consideration recent scientific findings on the biology of pejerrey and technological advances in seafood processing, storage and transportation, as well as the latest trends of seafood consumption and international markets. The best production strategy remains to be determined by trial and error but it is likely that, initially, production should focus on a differentiated, high‐quality fish for the premium or international markets rather than attempting to compete with the cheap fish from natural sources. An international cooperation project with Japan has successfully demonstrated the feasibility of breeding pejerrey in captivity and mass producing seeds efficiently in Argentina, and has provided the foundation for the development of intensive and extensive farming of this species.     

Evaluation of N2‐fixation measured by the 15N‐dilution and N‐difference methods in Nicaraguan and Ecuadorian Phaseolus vulgaris L. plants inoculated with Rhizobium leguminosarum biovar

Pot and field experiments were performed to assess N₂ fixation in Nicaraguan (R79 and R84) and Ecuadorian (Imba) common bean (Phaseolus vulgaris L.) cultivars, with the aim of improving their productivity by inoculating them with commercially produced Rhizobium phaseoli. With maize (Zea mays L.) as the non‐N₂‐fixing control, the percentage of N₂ fixed predicted by the ¹⁵N‐dilution method was significantly (P ≤ 0.05) higher than that predicted by the N‐difference method. However, the N₂ amounts predicted by the two methods were not significantly different. The correlation between the two methods was significant and positive (P ≤ 0.0001, n = 36). Compared with the native rhizobial strain, symbiotic associations of the bean cultivars with UMR1073, UMR1077 and UMR1899 rhizobial inoculants did not significantly (P ≤ 0.05) influence plant dry matter (DM) and N yields, the extent of N₂ fixation and uptake of soil and fertilizer N. Nevertheless, the UMR1077 and UMR1899 strains markedly increased the uptake of soil N by R84 plants, while decreasing N2 fixation. In contrast, the Imba‐UMR1899 association enhanced positive effects on all variables. About 60–70% of the total N taken up by the Imba plants was fixed N_2. The R79 and R84 plants fixed about 50% of their total N uptake. N₂ fixation rates were positively correlated with DM and total N yields, while being negatively correlated with soil N uptake (P ≤ 0.001, n = 36). Future research in Nicaragua should focus on selecting rhizobial strains suitable for indigenous common bean cultivars.     

Utility of inline milk fat and protein ratio to diagnose subclinical ketosis and to assign propylene glycol treatment in lactating dairy cows

The objective was to identify a fat-to-protein ratio (FPR) cut-off to diagnose subclinical ketosis (SCK) and to evaluate the effect of propylene glycol (PPG) treatment of cows with high FPR. The optimized cut-off was > 1.42; sensitivity (Se) = 92%; specificity (Sp) = 65%. A cut-off > 1.5 was selected for the PPG trial for balanced Se-Sp. Fat-to-protein ratio cut-offs > 1.25, 1.35, 1.50, 1.60, and 1.70 resulted in Se-Sp of 100% to 49%, 96% to 59%, 75% to 78%, 33% to 90%, and 8% to 96%, respectively. The proportions of cows with FPR > 1.25, 1.35, 1.42, 1.50, 1.60, and 1.70 were 60%, 50%, 44%, 30%, 14%, and 6%, respectively. Incidences of clinical ketosis and milk yield were similar between cows that received 400 mL of PPG (n = 34) and control cows (n = 38). Prevalence of SCK at enrollment was 29.2%; therefore, FPR > 1.5 is not indicated for treatment. Lower cut-offs should be used for screening.     

What variables are important in predicting bovine viral diarrhea virus? A random forest approach

Bovine viral diarrhea virus (BVDV) causes one of the most economically important diseases in cattle, and the virus is found worldwide. A better understanding of the disease associated factors is a crucial step towards the definition of strategies for control and eradication. In this study we trained a random forest (RF) prediction model and performed variable importance analysis to identify factors associated with BVDV occurrence. In addition, we assessed the influence of features selection on RF performance and evaluated its predictive power relative to other popular classifiers and to logistic regression. We found that RF classification model resulted in an average error rate of 32.03% for the negative class (negative for BVDV) and 36.78% for the positive class (positive for BVDV).The RF model presented area under the ROC curve equal to 0.702. Variable importance analysis revealed that important predictors of BVDV occurrence were: a) who inseminates the animals, b) number of neighboring farms that have cattle and c) rectal palpation performed routinely. Our results suggest that the use of machine learning algorithms, especially RF, is a promising methodology for the analysis of cross-sectional studies, presenting a satisfactory predictive power and the ability to identify predictors that represent potential risk factors for BVDV investigation. We examined classical predictors and found some new and hard to control practices that may lead to the spread of this disease within and among farms, mainly regarding poor or neglected reproduction management, which should be considered for disease control and eradication.

Electronic supplementary material

The online version of this article (doi:10.1186/s13567-015-0219-7) contains supplementary material, which is available to authorized users.     

Responses to photoperiod before and after jointing in wheat substitution lines

It has been hypothesised that wheat yields may be increased by lengthening the duration of the stemelongation phase. This paper reports studies on the effects of chromosomes carrying major photoperiod genes (Ppd-A1, Ppd-B1, Ppd-D1) in different genetic backgrounds, on responses to photoperiod before and after jointing, when the onset of stem elongation occurs, and on number of grains per spike. A field experiment considered the effects of two photoperiods on Chinese Spring and 12 substitution lines, in which chromosomes 2A, 2B or 2D had been substituted by those from four contrasting cultivars. The phase from seedling emergence to jointing (EM-JO) was more responsive than that from jointing to anthesis (JO-ANT), but no relationship was found between the duration of these phases. EM-JO length affected leaf and spikelet number and consequently grains per spike, but this component was further influenced by JO-ANT duration. Our results confirmed that the phases are independent in sensitivity, supporting the hypothesis that genetic manipulation of phase duration could enhance yield, but no evidence was found of any particular Ppd allele being responsible for major responses to photoperiod during stem elongation. This revised version was published online in July 2006 with corrections to the Cover Date.     

Breeding effects on sensitivity of barley grain weight and quality to events of high temperature during grain filling

Monogenic inheritance and linkage were established on the basis of F₁ observations and analysis of 13,498 plants in 42 crosses for leaf colour, 7046 plants in 27 crosses for plant pubescence, 1926 plants in 8 crosses for number of leaflets per leaf, and 3182 plants in 12 crosses for plant height under field conditions. Normal green colour of foliage was found to be dominant over light green, pubescent plant over glabrous, high number of leaflets per leaf over low number of leaflets, and tall plant over dwarf. Linkage was estimated from joint segregation analysis, taking two characters at a time in all possible combinations as significant χ² values were recorded for these genes. Gene symbols Gl, Pub, Ph, and Hl are proposed for these four traits, respectively. The genes are arranged in the order of Ph-Gl-Pub-Hl with the map distances of 21.1, 28.9, and 17.5 cM between them. This short sequence of four linked genes spanning over 37.2 cM has been called Linkage Group 2 of lentil.     

A rapid sample screening method for authenticity control of whiskey using capillary electrophoresis with online preconcentration

The present study aimed to develop a methodology using capillary electrophoresis for the determination of sinapaldehyde, syringaldehyde, coniferaldehyde, and vanillin in whiskey samples. The main objective was to obtain a screening method to differentiate authentic samples from seized samples suspected of being false using the phenolic aldehydes as chemical markers. The optimized background electrolyte was composed of 20 mmol L(-1) sodium tetraborate with 10% MeOH at pH 9.3. The study examined two kinds of sample stacking, using a long-end injection mode: normal sample stacking (NSM) and sample stacking with matrix removal (SWMR). In SWMR, the optimized injection time of the samples was 42 s (SWMR42); at this time, no matrix effects were observed. Values of r were >0.99 for the both methods. The LOD and LOQ were better than 100 and 330 mg mL(-1) for NSM and better than 22 and 73 mg L(-1) for SWMR. The CE-UV reliability in the aldehyde analysis in the real sample was compared statistically with LC-MS/MS methodology, and no significant differences were found, with a 95% confidence interval between the methodologies.