219 research outputs found
Effect of farming system changes on life cycle assessment indicators for dairy farms in the Italian Alps.
In some Alpine areas dairy farming is going through a process of intensification with significant changes in farming systems. The aim of this study was to investigate environmental performance of a sample of 31 dairy farms in an Alpine area of Lombardy with different levels of intensification. A cradle to farm gate life cycle assessment was performed including the following impact categories: land use, non-renewable energy use, climate change, acidification and eutrophication. From a cluster analysis it resulted that the group of farms with lowest environmental impacts were characterized by low stocking density and production intensity; farms that combined good environmental performances with medium gross margins were characterized also by high feed self-sufficiency and lowland availability. Environmental impacts of dairy farms in the mountain areas could be mitigated by the improvement of forage production and quality and by the practice of summer highland grazing, that significantly reduced eutrophication per kg of milk of the less self-sufficient farms
Supersymmetric Wilson loops via integral forms
We study supersymmetric Wilson loops from a geometrical perspective. To this end, we propose a new formulation of these operators in terms of an integral form associated to the immersion of the loop into a supermanifold. This approach provides a unifying description of Wilson loops preserving different sets of supercharges, and clarifies the flow between them. Moreover, it allows to exploit the powerful techniques of super- differential calculus for investigating their symmetries. As remarkable examples, we discuss supersymmetry and kappa-symmetry invariance
Effect of raw sunflower seeds on goat milk production in different farming systems
Aim of this study was to test the effect of raw sunflower seeds on goat milk production. Two farms with different farming systems (intensive and semi-intensive) participated to the trial. In each farm about 60 mid-lactation Alpine goats were divided in two groups during spring-summer time. A diet containing 5-6% of sunflower seeds on DM basis was compared with a control diet in a change-over design. In the semi-intensive farm milk yield of goats fed sunflower was 3.46 kg/d compared to 3.58 kg/d of goats fed control diet, whereas in the intensive farm milk yield was 4.60 kg/d vs 4.66 kg/d. Fat content increased significantly from 2.99% to 3.23% only in the intensive farm. The research in the intensive farm investigated also milk and cheese fatty acids composition. Medium and short chain fatty acids (C8-C16) content dropped and long chain fatty acids content increased when sunflower was added. In conclusion raw sunflower seed inclusion in dairy goat diets can be useful, in order to limit the inversion of fat and protein percentages in milk
T-Duality of Green-Schwarz Superstrings on AdS(d) x S(d) x M(10-2d)
We verify the self-duality of Green-Schwarz supercoset sigma models on AdS backgrounds (d=2,3,5) under combined bosonic and fermionic
T-dualities without gauge fixing kappa symmetry. We also prove this property
for superstrings on AdS (d=2,3) described by
supercoset sigma models with the isometries governed by the exceptional Lie
supergroups (d=2) and
(d=3), which requires an additional T-dualisation along one of the spheres.
Then, by taking into account the contribution of non-supercoset fermionic modes
(up to the second order), we provide evidence for the T-self-duality of the
complete type IIA and IIB Green-Schwarz superstring theory on AdS (d=2,3) backgrounds with Ramond-Ramond fluxes. Finally,
applying the Buscher-like rules to T-dualising supergravity fields, we prove
the T-self-duality of the whole class of the AdS
superbackgrounds with Ramond-Ramond fluxes in the context of supergravity.Comment: v2: 57 pages, 1 figure, typos fixed and clarifications added, version
to appear in JHE
Operator mixing in N=4 SYM: The Konishi anomaly revisited
In the context of the superconformal N=4 SYM theory the Konishi anomaly can
be viewed as the descendant of the Konishi multiplet in the 10 of
SU(4), carrying the anomalous dimension of the multiplet. Another descendant
with the same quantum numbers, but this time without anomalous
dimension, is obtained from the protected half-BPS operator (the
stress-tensor multiplet). Both and are renormalized mixtures
of the same two bare operators, one trilinear (coming from the superpotential),
the other bilinear (the so-called "quantum Konishi anomaly"). Only the operator
is allowed to appear in the right-hand side of the Konishi anomaly
equation, the protected one does not match the conformal properties of
the left-hand side. Thus, in a superconformal renormalization scheme the
separation into "classical" and "quantum" anomaly terms is not possible, and
the question whether the Konishi anomaly is one-loop exact is out of context.
The same treatment applies to the operators of the BMN family, for which no
analogy with the traditional axial anomaly exists. We illustrate our abstract
analysis of this mixing problem by an explicit calculation of the mixing matrix
at level g^4 ("two loops") in the supersymmetric dimensional reduction scheme.Comment: 28 pp LaTeX, 3 figure
A three-loop test of the dilatation operator in N=4 SYM
We compute the three-loop anomalous dimension of the BMN operators with
charges J=0 (the Konishi multiplet) and J=1 in N=4 super-Yang-Mills theory. We
employ a method which effectively reduces the calculation to two loops. Instead
of using the superconformal primary states, we consider the ratio of the
two-point functions of suitable descendants of the corresponding multiplets.
Our results unambiguously select the form of the N=4 SYM dilatation operator
which is compatible with BMN scaling. Thus, we provide evidence for BMN scaling
at three loops.Comment: 38 pages LaTeX, 4 figures, references adde
The Dilatation Operator of Conformal N=4 Super Yang-Mills Theory
We argue that existing methods for the perturbative computation of anomalous
dimensions and the disentanglement of mixing in N = 4 gauge theory can be
considerably simplified, systematized and extended by focusing on the theory's
dilatation operator. The efficiency of the method is first illustrated at the
one-loop level for general non-derivative scalar states. We then go on to
derive, for pure scalar states, the two-loop structure of the dilatation
operator. This allows us to obtain a host of new results. Among these are an
infinite number of previously unknown two-loop anomalous dimensions, new
subtleties concerning 't Hooft's large N expansion due to mixing effects of
degenerate single and multiple trace states, two-loop tests of various
protected operators, as well as two-loop non-planar results for two-impurity
operators in BMN gauge theory. We also put to use the recently discovered
integrable spin chain description of the planar one-loop dilatation operator
and show that the associated Yang-Baxter equation explains the existence of a
hitherto unknown planar ``axial'' symmetry between infinitely many gauge theory
states. We present evidence that this integrability can be extended to all
loops, with intriguing consequences for gauge theory, and that it leads to a
novel integrable deformation of the XXX Heisenberg spin chain. Assuming that
the integrability structure extends to more than two loops, we determine the
planar three-loop contribution to the dilatation operator.Comment: 54 pages, 5 figures, v2: references added, small textual changes, v3:
to appear in Nucl. Phys. B, v4: zeros in (D.21), signs in (F.4) correcte
Environmental impact of milk production in intensive farming systems: life cycle assessment approach
Life cycle assessment (LCA) has been shown to be a valuable method for the environmental evaluation of farming systems and has been applied to several agricultural products, particularly in Europe. In LCA the potential environmental impacts of a product are assessed by quantifying the resources consumed and the emissions, at all stages of its life cycle, from the extraction of resources, through the production and transport of materials, to the production process at the farm. The aim of the study was to evaluate the environmental impacts of milk production in intensive farming systems using LCA approach on a sample of 44 dairy farms in northern Italy. Impact categories were: Land use, Non-renewable energy use, Climate change, Acidification and Eutrophication. Functional units were: 1 kg of Fat and Protein Corrected Milk (FPCM); 1 ha of farm land. Data were collected by personal interview with the farmers. Farms involved in the study reared on average 145 (\ub191) cows, with a daily milk production of 28.0 (\ub13.32) kg FPCM/cow. Average farm land was 49.9 (\ub137) ha and stocking density 5.3 (\ub12.5) LU/ha. On average, 59% of the total dry matter of cow rations consisted of feed ingredients produced on the farm. The average results for the 5 LCA categories per kg of FPCM were: 2.84 (\ub11.02) m2 for Land use, 4.98 (\ub11.34) MJ for Energy use, 0.93 (\ub10.29) kg CO2-eq for Climate change, 18.2 (\ub14.2) g SO2-eq for Acidification and 12.0 (\ub13.1) g PO4-eq for Eutrophication. Impact indicators from this study are similar to those reported in recent European LC analyses on intensive dairy farms, although the comparison among LCA studies from different countries can be misleading because of local peculiarities and different methodologies. Within the study, LCA indicators allowed to compare environmental impacts of milk production among farms characterized by different levels of intensification (stocking density, milk production, feed self-supply)
Impact of Staphylococcus aureus infection on the late lactation goat milk proteome: New perspectives for monitoring and understanding mastitis in dairy goats
The milk somatic cell count (SCC) is a standard parameter for monitoring intramammary infections (IMI) in dairy ruminants. In goats, however, the physiological increase in SCC occurring in late lactation heavily compromises its reliability. To identify and understand milk protein changes specifically related to IMI, we carried out a shotgun proteomics study comparing high SCC late lactation milk from goats with subclinical Staphylococcus aureus IMI and from healthy goats to low SCC mid-lactation milk from healthy goats. As a result, we detected 52 and 19 differential proteins (DPs) in S. aureus-infected and uninfected late lactation milk, respectively. Unexpectedly, one of the proteins higher in uninfected milk was serum amyloid A. On the other hand, 38 DPs were increased only in S. aureus-infected milk and included haptoglobin and numerous cytoskeletal proteins. Based on STRING analysis, the DPs unique to S. aureus infected milk were mainly involved in defense response, cytoskeleton organization, cell-to-cell, and cell-to-matrix interactions. Being tightly and specifically related to infectious/inflammatory processes, these proteins may hold promise as more reliable markers of IMI than SCC in late lactation goats.
Significance: The biological relevance of our results lies in the increased understanding of the changes specifically related to bacterial infection of the goat udder in late lactation. The DPs present only in S. aureus infected milk may find application as markers for improving the specificity of subclinical mastitis monitoring and detection in dairy goats in late lactation, when other widespread tools such as the SCC lose diagnostic value
Proteomic datasets of uninfected and Staphylococcus aureus-infected goat milk
We present a proteomic dataset generated from half-udder Alpine goat milk. The milk samples belonged to 3 groups: i) mid-lactation, low somatic cell count, uninfected milk (MLU, n=3); ii) late lactation, high somatic cell count, uninfected milk (LHU, n=3); and late lactation, high somatic cell count, Staphylococcus aureus subclinically infected milk (LHS, n=3). The detailed description of results is reported in the research article entitled \u201cImpact of Staphylococcus aureus infection on the late lactation goat milk proteome: new perspectives for monitoring and understanding mastitis in dairy goats\u201d. After milk defatting, high speed centrifugation and trypsin digestion of milk with the FASP protocol, peptide mixtures were analyzed by LC-MS/MS on a Q-Exactive. Peptide identification was carried out using Sequest-HT in Proteome Discoverer. Then, the Normalized Abundance Spectrum Factor (NSAF) value was calculated by label free quantitation using the spectral counting approach, and Gene Ontology (GO) annotation by Uniprot was carried out by reporting biological process, molecular function and cellular component. The MS data have been deposited to the ProteomeXchange via the PRIDE with the dataset identifier PXD017243
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