Reproducibility of observables and coherent control in molecular photoionization: from continuous wave to ultrashort pulsed radiation

One-photon single ionization of molecules has been at the focus of several discussions concerning the reconstruction of observables obtained with ultrashort pulses from those obtained from continuous wave radiation (and vice versa). A related controversy on the conditions and observables that allow for coherent control in one-photon processes has been recently revisited (Science 2006, 313, 1257; J. Chem. Phys. 2010, 133, 151101). Our benchmark to investigate these issues is photoionization of the hydrogen molecule, where the autoionization events are the time-dependent processes in field-free evolution that could serve as a target for coherent control. We show that the variation of one-photon ionization probabilities with pulse duration are solely due to spectral effects and thus cannot be coherently controlled. We then discuss for which observables and under which conditions phase control of autoionization dynamics is possible.

Observation of interference between two distinct autoionizing states in dissociative photoionization of H2

Dissociative photoionization (DPI) of randomly oriented H(2) molecules has been studied using linearly polarized synchrotron radiation at selected photon energies of 31, 33, and 35 eV. Large amplitude oscillations in the photoelectron asymmetry parameter β, as a function of electron energy, have been observed. The phase of these β oscillations are in excellent agreement with the results of recent close coupling calculations [Fernández and Martín, New J. Phys. 11, 043020 (2009)]. We show that the oscillations are the signature of interferences between the 1Q(1) (1)Σ(u)(+) and 1Q(2) (1)Π(u) doubly excited states decaying at different internuclear distances. The oscillations thus provide information about the classical paths followed by the nuclei. The presence of such oscillations is predicted to be a general phenomenon in DPI.

Susceptibility to peroxidation and fatty acid composition of fresh boar semen obtained from different hog farms

<p>Objectives of this study were to determine the fatty acid composition and to analyze the sensitivity to lipid peroxidation of different boar fresh semen samples from two herds, H1 and H2. Lipid peroxidation was evaluated using chemilu­minescence (cpm/mg of protein) and fatty acid profile by means of gas chromatography. The saturated fatty acid content found in the analyzed spermatozoa was approximately 43% in H1 and 33% in H2, whereas the total unsaturated fatty acid content was 47% in H1 and 59% in H2. When control and ascorbate-Fe++ dependent samples were compared, it was observed a significant increase in light emission. Consequently, significant decrease in the percentage of the polyunsaturated fatty acids was determined, being more affected: C22: 5 n6 and C22: 6 n3 in both herds, whereas C20: 4 n6 and C22: 4 n6 only in H2. The great amounts of polyun­saturated fatty acids found in H2 samples could be related to the loss of acrosomal integrity. Our results indicate that boar semen contains great amounts of polyunsaturated fatty acid in its composition, which were vulnerable to the lipid peroxidation.</p>

Components of (co)variance of the days open in Siboney dairy cows

The records of 63,406 calvings of Siboney dairy cows (5/8 Holstein 3/8 Cuban Zebu) were used to estimate the components of covariance of the days open (DO). Five models were used: of repeatability; univariate; bivariate; of random regression with Legendre polynomials and the parity number as predicting variable; and a model of random regression with Legendre polynomials and heterogeneity of the residual variance. The heritability obtained with the univariate model was 0.09 in the first calving and decreased to 0.05 in the fifth. A higher estimate of heritability (0.12) was obtained with the repeatability model. When the model of random regression with heterogeneity of the residual variance was used, the heritability was higher than the values estimated with the previous models. The genetic correlations among the DO in different calvings, estimated with the models of random regression with and without heterogeneity of the residual variance, were close to 1.0. It is concluded that the estimates of heritability increased with the use of the random regression models. The genetic correlations among the DO of different calvings indicated that in the first three, the DO are regulated for the most part by the same genes.

Two-electron time-delay interference in atomic double ionization by attosecond pulses

A two-color two-photon atomic double ionization experiment using subfemtosecond uv pulses can be designed such that the sequential two-color process dominates and one electron is ejected by each pulse. Nonetheless, ab initio calculations show that, for sufficiently short pulses, a prominent interference pattern in the joint energy distribution of the sequentially ejected electrons can be observed that is due to their indistinguishability and the exchange symmetry of the wave function.

[Oral nutritional supplementation in hematologic patients]

RATIONALE

Hematological patients often present anorexia which along with other secondary effects from the chemotherapy and/or radiotherapy treatments compromise their nutritional status. Oral supplementation can aid to fulfill the energy and protein requirements of these patients. Nevertheless, the use of commercial nutritional supplements normally available, is limited by its poor intake.

OBJECTIVE

To evaluate the degree of fulfillment of the prescribed supplements and fulfillment of energy requirements, as well as the development of nutritional status in hematological patients hospitalized for treatment with chemotherapy and/or radiotherapy.

METHODS

Prospective, randomized and open study of inpatients at the hematological ward. Patients were randomized sequentially and they were assigned into 3 different nutritional interventions providing: Group 1 (G1), a flavored supplement; Group 2 (G2): a non flavored (neutral) supplement and Group 3 (G3): "kitchen" foods as supplements. Need and amount of nutritional supplements were provided according to the oral intake previously analyzed. Nutritional assessment (at admission and discharge) was based in the Subjective Global Assessment test (SGA), Risk Nutritional Index (RNI) and percentage of lost weight. Both fulfillment of supplement intake and achievement of energetic requirements were analyzed.

RESULTS

125 patients of 51.3 +/- 16.8 years; 45% men and 55% women.

DIAGNOSIS

54% lymphoma, 33% leukemia, 8% myeloma and others 4%. Length of stay (LOS): 7.0 +/- 3.6 d. The nutritional assessment done by SGA showed significant negative changes in G2 and G3 (G1: 30% developed malnutrition and 28% improved their nutritional status, p = NS; G2: 50% developed malnutrition against 7% whom improved their nutritional status, p = 0.002; y G3: 37% developed malnutrition against 21% whom improved their nutritional status, p = 0.02). According to RNI, patients evolved negatively from their nutritional state but no significant differences were found within groups (G1, from 81% of malnutrition to 90%; G2, from 77% to 91%, and G3 from 71% to 85%). Globally, during hospitalization patients lost weight significantly (2.3 +/- 2.2 kg, p < 0.001), but within groups weight loss differences were not significant (G1, 1.16 kg; G2, 1.75 kg, y G3, 1.17 kg). All three groups required intake of supplements (G1, 47%; G2, 30%, and G3, 47%). The percentage of fulfillment of oral intake was similar in both commercial supplemented groups (G1, 47% and G2, 58%) although it was significantly greater in those receiving kitchen supplements (G3, 100%, p < 0.001). The fulfillment of energy requirements at admission and discharge did not showed significant changes (G1, from 53% to 46%; G2, from 67% to 52% and G3 from 49% to 55%).

CONCLUSION

Our results suggest that hematological patients admitted to hospital for treatment with chemotherapy and/or radiotherapy loose weight during their hospitalization and present intakes below their energy requirements so they need supplementation. Kitchen supplements are better accepted than commercial ones although that does not result in an increased total energy intake. The group which received commercial flavored supplements was the only one which did not showed negative significant changes in the nutritional status evaluated by SGA.