SALVADOR DE LA PLAZA Y LA REFORMA AGRARIA EN VENEZUELA 19421954

El trabajo analiza algunos ensayos de Salvador De La Plaza sobre el tema de la reforma agraria en Venezuela, escritos entre 1942 y 1954, después de su segundo destierro. Entre 1937 y 1942, en efecto, vive en México donde asiste a los cambios sociales determinados por la reforma agraria y la nacionalización del petróleo. La necesidad de una reforma agraria en el país y sus relaciones con las transformaciones de la sociedad venezolana son objeto de una profunda reflexión que une el rigor científico y el análisis marxista de la realidad de su país, a la pasión del militante que afronta, en más de una ocasión, la cárcel y el destierro para sostener con coherencia sus ideas

Effect of suckling management on productive performance and carcass traits of Comisana lambs.

The effect of restricted suckling on productive performance and carcass traits of growing lambs was determined. Twenty-one naturally sucked male Comisana lambs were divided into three equal weight groups with differing suckling management systems: 1) only maternal milk (C); 2) only maternal milk until 15 d of age and, from 16 d of age to slaughter, maternal milk, concentrate and hay ad libitum (T1); 3) only maternal milk until 15 d of age and, from 16 d to 30 d of age, maternal milk, concentrate and hay ad libitum, and, from 31 d of age to slaughter, only concentrate and hay ad libitum (T2). Average daily weight gain (ADG) and milk and feed intake were calculated. Ewe milk was collected from each group. At slaughter (63 d) live weight and carcass measurements were recorded. The overall mean of total milk collected was 22.7 and 41.6 kg ewe-1 for T1 and T2, respectively. Suckling management system significantly affected ADG, milk intake, dressing percentage, and percentages of intestines, stomachs, offals, and kidney fat. Suckling management appears to be an important factor affecting lamb growth and carcass quality

Analysis of anaerobic power in club level young rowers

Aim: To date, assessment of the anaerobic components to determine performance in rowers is not part of standard evaluation or monitoring set for training. The aim of this study was to evaluate the relation between anaerobic power output and ergometer rowing performance over 2000 meters, in a group of 14 -17 years old rowers (n = 11). Methods: Each subject performed, in three separate days, two “all-out” tests, over 20 and 60 seconds, and a 2000 meters trial, using a Concept II rowing ergometer. Mean power values over 20 sec (W20) and 60 sec (W60) were measured and compared with the time to perform the 2000 m trial (t2000). Results: Statistical analysis showed high and significant correlation between 2000 meters performance (6.90 ± 0.1 min) and anaerobic power over 20 sec (479.5 ± 93.90 watts; r = 0.941, P = 0.00002) and 60 sec (435.5 ± 64.60 watts; r = 0.964, P = 0.000002). Conclusions: The data of our study confirm that parameters of anaerobic power strongly affect the performance and that the determination of these variables by testing on rowing ergometer can be an useful tool for planning and monitoring of training in young rowers

Directional detection of light dark matter from three-phonon events in superfluid 4^4He

We present the analysis of a new signature for light dark matter detection with superfluid $^4$He: the emission of three phonons. We show that, in a region of mass below the MeV, the kinematics of this process can offer a way to reconstruct the dark matter interaction vertex, while providing background rejection via coincidence requirements and directionality. We develop all the necessary technology to deal with such an observable, and compute the associated differential distributions.Comment: 8 pages, 4 figures. Version published in Physical Review

Relationship Between Heart Rate Recovery After Exercise and Maximal Oxygen Uptake in Sedentary Patients with Type 2 Diabetes

AIMS: Heart rate recovery after exercise (HRR) is an estimate of autonomic modulation of the heart, and has been shown to be inversely associated with type 2 diabetes. Type 2 diabetes is associated with decreased maximal oxygen consumption (VO2max). Aim of our study was to assess the relationship between HRR and VO2max in sedentary patients with type 2 diabetes. METHODS: Maximal exercise testing to determine VO2max (ml ∙ Kg-1 ∙ min-1) was performed in 16 sedentary patients with type 2 diabetes (DP) and in 16 age-matched sedentary healthy controls (HS). HRR (bpm) 2 min after cessation of the exercise was recorded. Simple linear regression was used to assess the relations between HRR and VO2max. RESULTS: VO2max and HRR were significantly lower in DP compared to HS (P = 0.002 and P = 0.008 respectively). A correlation between HRR and VO2max has been found, stronger in DP (r = 0.672, P = 0.004) than HS (r = 0.620, P = 0.01). CONCLUSIONS: Our study suggests that regular physical activity aimed to improve the levels of VO2max in subjects with diabetes may improve the HRR and reduce the risk of cardiovascular events

Immunohistochemical expression and distribution of orexin, orphanin and leptin in the major salivary glands of some mammals

Abstract: The aim of the study was to assess the involvement of apoptotic factors, cytokeratins and metalloproteinase- 9 in the histogenesis of both Epithelialized Gingival Lesions (EGL) and Periapical Lesions (PAL). 55 consecutive patients, 30 with PAL and 25 with EGL, were selected for the study after clinical and radiological examinations. The PAL patients had severe periapical lesions and tooth decay with exposure of the pulp chamber. All PAL and EGL biopsies were surgically extracted, fixed in 10% buffered formalin, and processed for routine light microscopy. Ten biopsies of each category were processed for immunohistochemistry (IHC). Serial paraffin sections were stained by IHC with appropriate antibodies to detect cytokeratins (CKs) 1, 5, 8, 10 and 14, caspase-3 and -9, metalloproteinase-9, and for PCNA and TUNEL assays. Both PAL and EGL showed a high expression of the cytokeratin 1, 5 and 8 with higher expression in EGL. Moreover, CK10 was markedly less intense expressed in EGL compared to PAL, while CK14 was almost three times stronger expressed in EGL. The expression of caspase-3 and -9 was stronger in PAL compared to EGL, however, the difference was only significant for caspase-9. In PAL apoptosis detected by TUNNEL method and the expression of MMP-9 were higher than in EGL, whereas PCNA was significantly more expressed in EGL. The results clearly suggest that both lesions have exclusively an epithelial origin and that epithelial proliferation was correlated with the degree of apoptosis in both entities. PAL and EGL presented mostly similar cytokeratin expression except for CK10 and CK14, though with marked differences in the distribution and intensity of IHC reactions. Finally, the degradation of extracellular matrix in both lesions could be partially attributed to the strong presence of MMP-9. (Folia Histochemica et Cytobiologica 2012, Vol. 50, No. 4, 497–503)The aim of the study was to determine by immunochemistry the expression of leptin, orexin A and orphanin FQ in the major salivary glands (parotid, submandibular and sublingual) of rat, sheep and cow. These peptides, originally synthesized in central nervous system, adipose tissue and peripheral tissues including gastrointestinal tract, play an orexigenic (orphanin and orexin) or anorexigenic (leptin) roles in the intricate neuronal network appointed to the control of nutritional homeostasis. Peptide-specific immunoreactivity was present in the studied salivary glands with various intensities in different species, in the ductal epithelium, sometimes in the acinar epithelium, and in nervous trunks spread in connective tissue stroma. The obtained data show that salivary glands present an unexpected source of orexigenic and anorexigenic peptides which with their autocrine, paracrine, and endocrine mechanisms of action may participate in the control of salivary gland function

Relationship between heart rate variability and repeated sprint exercise in young soccer players

Aim: The sport of soccer is characterized by neuromuscular performance resulting in short bursts interspersed by brief recovery periods over an extended period of time. Several studies suggest that the cardiac autonomic nervous system (ANS) assessed by heart rate variability (HRV) may provide useful information regarding the functional adaptations to training stimulus. Although HRV has often been associated with aerobic power and cardiovascular fitness, the influence of sympathovagal balance on neuromuscular performance in young athletes is not well assessed. The aim of this study was to assess the influence of the autonomic system on the performance of repeated sprints, involving predominantly muscular power and anaerobic metabolism, in young soccer players. Method: Twelve young soccer players, selected for the Sicilian Regional Representative of the Italian Football Federation, mean age 15 years, were recruited. Resting HRV was measured and indices of power spectral analysis (ratio LF/HF) were calculated to evaluate the sympathovagal balance. To assess the state of physical fitness of subjects, VO2max was determined by maximal graded treadmill test. Finally, the athletes performed 10 maximal all-out 6-sec cycling sprints (RS), interspersed with 30-sec of passive recovery, to measure the peak power (PP) represented by the highest value recorded during a single sprint, and the average of the values of maximum power (AP) recorded during all sprints. Results: On the basis of their VO2max (56.22 ± 3.93 ml/Kg/min), all subjects showed good levels of physical fitness. HRV index (LF/HF = 1.31 ± 0.74) showed an inverse correlation with PP (14.05 ± 0.89 W/Kg; r = -0.709, P = 0.01), and with AP (12.82 ± 0.88 W/Kg; r = -0.606, P = 0.04). Conclusion: Our study shows that a low ratio LF/HF, which reflects a parasympathetic predominance in the ANS balance, is associated with a better anaerobic contribution to performance resulting in higher values of PP and AP during brief repeated maximal cycling sprints. The assessment of resting HRV before exercise may be useful for performance monitoring of young soccer players

Synthesis and Photovoltaic Properties of Regioregular Head-to-Head Substituted Thiophene Hexadecamers

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Diffusive transport and self-consistent dynamics in coupled maps

The study of diffusion in Hamiltonian systems has been a problem of interest for a number of years. In this paper we explore the influence of self-consistency on the diffusion properties of systems described by coupled symplectic maps. Self-consistency, i.e. the back-influence of the transported quantity on the velocity field of the driving flow, despite of its critical importance, is usually overlooked in the description of realistic systems, for example in plasma physics. We propose a class of self-consistent models consisting of an ensemble of maps globally coupled through a mean field. Depending on the kind of coupling, two different general types of self-consistent maps are considered: maps coupled to the field only through the phase, and fully coupled maps, i.e. through the phase and the amplitude of the external field. The analogies and differences of the diffusion properties of these two kinds of maps are discussed in detail.Comment: 13 pages, 14 figure

Nanofat 2.0: experimental evidence for a fat grafting rich in mesenchymal stem cells.

Different strategies have been developed in the last decade to obtain fat grafts as rich as possible of mesenchymal stem cells, so exploiting their regenerative potential. Recently, a new kind of fat grafting, called "nanofat", has been obtained after several steps of fat emulsification and filtration. The final liquid suspension, virtually devoid of mature adipocytes, would improve tissue repair because of the presence of adipose mesenchymal stem cells (ASCs). However, since it is probable that many ASCs may be lost in the numerous phases of this procedure, we describe here a novel version of fat grafting, which we call "nanofat 2.0", likely richer in ASCs, obtained avoiding the final phases of the nanofat protocol. The viability, the density and proliferation rate of ASCs in nanofat 2.0 sample were compared with samples of nanofat and simple lipoaspirate. Although the density of ASCs was initially higher in lipoaspirate sample, the higher proliferation rate of cells in nanofat 2.0 virtually filled the gap within 8 days. By contrast, the density of ASCs in nanofat sample was the poorest at any time. Results show that nanofat 2.0 emulsion is considerably rich in stem cells, featuring a marked proliferation capability