2,659 research outputs found
Green public procurement criteria for road infrastructures: State of the art and proposal of a weighted sum multicriteria analysis to assessenvironmental impacts
In the last years, the attention to environmental issue is growing, demonstrating the interest to protect the nature and to better use the non-renewable resources. At international level, and especially in the European Community, for different trades, a wide production of voluntary documents and institutional acts proves the interest and the need for a green economy. An innovative approach may lead to the experience of Green Public Procurements (GPP), to protect the environment as a public interest and to promote technological developments. So far, the experiences of GPP are limited, not entirely positive and in the field of road infrastructures almost entirely absent. Construction and maintenance of road infrastructures is objectively more complex than purchasing goods or services. The paper proposes the integration of the weighted sum multi-criteria analysis into existing procedures. The methodology needs for environmental labels related to materials, machines and works which contribute to the final product "road". The labels are recognized at international level and consistent with procedures, conditions and criteria currently published in road tenders, therefore the approach can be followed to pursue the environmental sustainability of road infrastructures without compromising the economic attention
The Noncommutative Geometry of the Quantum Projective Plane
We study the spectral geometry of the quantum projective plane CP^2_q, a
deformation of the complex projective plane CP^2, the simplest example of a
spin^c manifold which is not spin. In particular, we construct a Dirac operator
D which gives a 0^+ summable spectral triple, equivariant under U_q(su(3)). The
square of D is a central element for which left and right actions on spinors
coincide, a fact that is exploited to compute explicitly its spectrum.Comment: v2: 26 pages. Paper completely reorganized; no major change, several
minor one
Polariton-polariton scattering in microcavities: A microscopic theory
We apply the fermion commutation technique for composite bosons to
polariton-polariton scattering in semiconductor planar microcavities.
Derivations are presented in a simple and physically transparent fashion. A
procedure of orthogonolization of the initial and final two-exciton state
wavefunctions is used to calculate the effective scattering matrix elements and
the scattering rates. We show how the bosonic stimulation of the scattering
appears in this full fermionic approach whose equivalence to the bosonization
method is thus demonstrated in the regime of low exciton density. We find an
additional contribution to polariton-polariton scattering due to the exciton
oscillator strength saturation, which we analyze as well. We present a theory
of the polariton-polariton scattering with opposite spin orientations and show
that this scattering process takes place mainly via dark excitonic states.
Analytical estimations of the effective scattering amplitudes are given.Comment: Theoretical paper on polariton-polariton scattering in planar
microcavities. The new version contains a slightly modified abstract and a
revised introduction. Typos have been corrected wherever spotted. 16 page
Origin of the v. portae and variability of its tributaries in laboratory animals. V. The golden (Syrian) hamster (Mesocricetus auratus).
The authors studied the origin and variability of the v. portae in 30 adult golden hamsters (Mesocricetus auratus) of both sexes after injecting blue-dyed latex into their portal bed. In 16 cases (53.3%) the v. portae was formed from three tributaries and in 11 cases (36.7%) from four. The v. mesenterica cranialis was the only constant tributary, the v. lienalis was a tributary in 28 cases (93.3%) and the other most frequent tributaries were the v. gastroduodenalis and the v. pancreaticoduodenalis cranialis. In one case there was an anastomosis between the v. portae and the v. cava caudalis. In 25 cases (83.3%) the v. gastrica sinistra joined the v. lienalis, in four (13.3%) it was an independent tributary of the v. portae and in one case (3.3%) it was duplicated. A v. cardiaca was found in 25 cases (83.3%), when it was most frequently a tributary of the v. gastroepiploica sinistra and v. gastrica sinistra. In one case only it was an independent tributary of the v. portae. A v. pylorica was observed in 29 cases (96.7%), usually (in 17 cases--56.7%) as a tributary of the v. gastroepiploica dextra; in three cases it was an independent tributary of the v. portae (10.0%). A v. pancreaticoduodenalis cranialis was formed in 28 cases (93.3%). In 12 cases (40.0%), together with the v. gastroepiploica dextra, it was a tributary of the v. gastroduodenalis and in eight cases (26.7%) it was an independent tributary of the v. portae. In two cases (6.7%) the two vv. pancreaticoduodenales united to form v. pancreaticoduodenalis communis. In three cases (10.0%) this vein was duplicated and in one case it was triplicated. A v. gastroepiploica dextra was found in 26 cases (86.7%) and a v. gastroepiploica sinistra in 22 (73.3%). Both veins occurred simultaneously in 19 cases (63.3%). In no case, however, was there a continuous venous arc along the curvatura major ventriculi. A v. lienalis was present in 28 cases (93.3%). It was absent in two cases (6.7%), in which it was replaced by inter-organ anastomoses with the stomach and pancreas. In 19 cases (63.3%), the v. gastroepiploica sinistra and v. gastrica sinistra were both its main tributaries and in five cases (16.7%) its main tributary was the v. gastrica sinistra. In one case the v. lienalis was duplicated. Inter-organ anastomoses were formed in all 30 cases (100%). They occurred between the spleen and the stomach in 27 cases (90%) and between the spleen and the pancreas in 28 cases (93.3%).(ABSTRACT TRUNCATED AT 400 WORDS
Variability of the v. cava caudalis and its tributaries in some laboratory animals. I. The guinea pig (Cavia aperea f. porcellus).
The authors studied variability of the v. caudalis and its tributaries in 30 guinea pigs (Cavia aperea f. porcellus--15 males and 15 females) after injecting the relevant venous system with blue-dyed latex. Since the largest lobe of the guinea pig's liver (the lobus sinister) is situated on the left, the right kidney lies further cranially than the left one. In males, as a rule, the right v. renalis opens into the v. cava caudalis further cranially than the left one. The number of vv. renales showed no sex-related differences, although in 17 regions (i.e. in 29%) there was more than one. The increase most often concerned the v. renalis dextra (the ratio in relation to the left vein was 15:2). The tributaries of the vv. renales are the v. spermatica or v. uterina cranialis a v. lumbalis and a v. or vv. suprarenales. There are usually two tributaries, (the commonest of which is the v. spermatica or v. uterina cranialis) on both the right and the left side, though somewhat more frequently on the left (23:19). Blood is drained from the surface or capsule of the kidney relatively often (in 75% of the cases) by the capsularis, which is the most frequent tributary of the v. spermatica or v. uterina cranialis of the corresponding side. Vv. suprarenales (1-4) are a constant finding on both sides. In males they open more often into the v. cava caudalis and in both sexes they also open into the v. renalis and v. lumbalis. The v. spermatica dextra opened into the v. renalis dextra in 10 cases and the v. spermatica sinistra into the v. renalis sinistra in 12 cases. The v. uterina cranialis dextra was a tributary of the v. renalis dextra in eight cases and the v. uterina cranialis sinistra joined the v. renalis sinistra in 13 cases. Drainage into the v. renalis can thus be regarded as the norm in both sexes and on both sides. The v. uterina caudalis leads from the corpus and cervix uteri and joins the v. uterina cranialis. It has a regular incidence and caudally it is most often a tributary of the v. iliaca communis. The v. ovarica is a constant tributary of the v. uterina cranialis; it is usually joined by several vv. lumbales or v. v. capsulares.(ABSTRACT TRUNCATED AT 400 WORDS
Variability of the v. cava caudalis and its tributaries in some laboratory animals. II. The laboratory rat (Rattus norvegicus v. alba).
Duplication of the v. renalis was found in 11 of the regions examined (18.3%), when it was more frequent on the right side. A v. capsularis was found in 35 regions (58.3%), usually as a single vein. There were 1-3 vv. suprarenales (but mostly two; on the right they usually joined the v. cava caudalis and on the left the v. renalis sinistra). A v. spermatica was present on the right side in every case, but on the left side in 11 cases only; in one case it was duplicated. In the rat, the v. spermatica was rather thin; if absent, it was replaced by the v. deferentialis. In nine cases (60.0%) the v. uterina cranialis dextra opened into the v. cava caudalis, while in 12 cases (80.0%) the left vein opened into the v. renalis sinistra. A v. uterina media, draining blood from the caudal third of the cornu uteri, was found in only five cases (16.7%). The v. uterina caudalis drained blood from the corpus and cervix uteri. The v. ovarica was a constant finding; it was mostly joined by the v. lumbalis--and on the left side by the v. phrenica sinistra. In males, the vv. lumbales occurred mostly as a pair of veins lying just below the vv. renales. In females, they were present on both sides. As a rule, the v. iliolumbalis occurred as a single vein on both sides. The v. cava caudalis originated at the level of the transition between the lumbar and the sacral spine, usually at the confluence of the two vv. iliacae communes, which in 14 cases (46.7%) were joined by the v. sacralis mediana. Duplication of the v. cava caudalis was found in only one case (a female). Comparison of the morphology of the v. cava caudalis and its tributaries in the rat and the guinea pig showed more slight differences between the two species
Prognostic significance of primary-tumor extension, stage and grade of nuclear differentiation in patients with renal cell carcinoma
Surgery remains the preferred therapy for renal cell carcinoma. The various adjunctive or complementary therapies currently yield disappointing results. Identifying reliable prognostic factors could help in selecting patients most likely to benefit from postoperative adjuvant therapies. We reviewed the surgical records of 78 patients who had undergone radical nephrectomy with lymphadenectomy for renal cell carcinoma, matched for type of operation and histology. According to staging (TNM), 5.1% of the patients were classified as stage I, 51.3% as stage II, 29.5% as stage III and 14.5% as stage IV. Of the 78 patients 40 were T2N0 and 21 T3aN0. Tumor grading showed that 39.7% of the patients had well-differentiated tumors(G1), 41.1% moderately-differentiated (G2), and 19.2% poorly-differentiated tumors (G3). Overall actuarial survival at 5 and 10 years was 100% for stage 1; 91.3% at 5 years and 83.1% at 10 years for stage II; 45.5% and 34.1% for stage III; and 29.1% and nil for stage IV (stage II vs stage III p = 0.0001). Patients with tumors confined to the kidney (pT2N0) had better 5- and 10-year survival rates than patients with tumors infiltrating the perirenal fat (pT3aN0) (p = 0.000006). Survival differed according to nuclear grading (G1 vs G3 ; p = 0.000005; G2 vs G3; p = 0.0009). In conclusion our review identified tumor stage, primary-tumor extension, and the grade of nuclear differentiation as reliable prognostic factors in patients with renal cell carcinomas
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