Organsko-geohemijska korelacija nekih nafti depresije Drmno (južni deo panonskog basena, Jugoslavija)

The results of an investigation of crude oils originating from the Sirakovo and Bradarac-Maljurevac localities (southern part of the Pannonian Basin) are reported in this paper. The aim was to estimate the organic geochemical similarity of the crude oils fi om the DI mno (Kostolac) depression oil fields. The nine selected samples originated from reservoir. rocks of various depths. Reliable source and organic geochemical maturation parameters served as the basis for the correlation studies. The similar origin of the investigated DI mno depression crude oils was corroborated, characterized by a significant participation of terrestrial precursor biomass. They were shown to be of relatively low maturity and to have been formed during the earlier stages of the diagenet- ic-catagenetic sequence of processes leading to the formation of crude oils, most probably in source rocks of Tertiary age, corresponding to vitrinite reflectances between Ro = 0.70 % and Ro = 0.80%. The crude oils from Bradarac-Maljurevac seemed to be somewhat less homogeneous with respect to organic geochemical parameters compared to Sirakovo crude oils.U ovom radu ispitivani su uzorci sirovih nafti depresije Drmno (Kostolac) sa lokaliteta Sirakovo i Bradarac-Maljurevac. Cilj rada bio je da se proceni organsko-geohemijska ujednačenost nafti naftnih polja depresije Drmno. Izabrani su uzorci koji potiču iz rezervoarskih stena sa različitih dubina i u njima su određeni grupni i specifični izvorni i maturacioni organsko-geohemijski parametri. Potvrđeno je da ispitivani uzorci depresije Drmno imaju slično poreklo koje karakteriše veći udeo terestrijalne prekursorske biomase. Ispitivane nafte su nešto nižeg stepena maturisanosti i nastale su u ranijim fazama dijagenetsko-katagenetske sekvencije formiranja nafte kojima odgovaraju vrednosti refleksije vitrinita između Ro = 0,70 % i Ro = 0,80 %. Najverovatnije su nastale u izvornim stenama tercijarne starosti. Nafte sa lokaliteta Bradarac-Maljurevac karakteriše nešto niži nivo organsko-geohemijske homogenosti nego nafte sa lokaliteta Sirakovo

Glucocorticoids, master modulators of the thymic catecholaminergic system?

There is evidence that the major mediators of stress, i.e., catecholamines and glucocorticoids, play an important role in modulating thymopoiesis and consequently immune responses. Furthermore, there are data suggesting that glucocorticoids influence catecholamine action. Therefore, to assess the putative relevance of glucocorticoid-catecholamine interplay in the modulation of thymopoiesis we analyzed thymocyte differentiation/maturation in non-adrenalectomized and andrenalectomized rats subjected to treatment with propranolol (0.4 mg.100 g body weight(-1).day(-1)) for 4 days. The effects of beta-adrenoceptor blockade on thymopoiesis in non-adrenalectomized rats differed not only quantitatively but also qualitatively from those in adrenalectomized rats. In adrenalectomized rats, besides a more efficient thymopoiesis [judged by a more pronounced increase in the relative proportion of the most mature single-positive TCR alpha beta(high) thymocytes as revealed by two-way ANOVA; for CD4(+)CD8(-)F (1,20) = 10.92, P lt 0.01; for CD4(-)CD8(+)F (1,20) = 7.47, P lt 0.05], a skewed thymocyte maturation towards the CD4(-)CD8(+) phenotype, and consequently a diminished CD4(+)CD8(-)/CD4(-)CD8(+) mature TCR alpha beta(high) thymocyte ratio (3.41 +/- 0.21 in non-adrenalectomized rats vs 2.90 +/- 0.31 in adrenalectomized rats, P lt 0.05) were found. Therefore, we assumed that catecholaminergic modulation of thymopoiesis exhibits a substantial degree of glucocorticoid-dependent plasticity. Given that glucocorticoids, apart from catecholamine synthesis, influence adrenoceptor expression, we also hypothesized that the lack of adrenal glucocorticoids affected not only beta-adrenoceptor- but also alpha-adrenoceptor-mediated modulation of thymopoiesis

Crop pests and predators exhibit inconsistent responses to surrounding landscape composition

The idea that noncrop habitat enhances pest control and represents a win–win opportunity to conserve biodiversity and bolster yields has emerged as an agroecological paradigm. However, while noncrop habitat in landscapes surrounding farms sometimes benefits pest predators, natural enemy responses remain heterogeneous across studies and effects on pests are inconclusive. The observed heterogeneity in species responses to noncrop habitat may be biological in origin or could result from variation in how habitat and biocontrol are measured. Here, we use a pest-control database encompassing 132 studies and 6,759 sites worldwide to model natural enemy and pest abundances, predation rates, and crop damage as a function of landscape composition. Our results showed that although landscape composition explained significant variation within studies, pest and enemy abundances, predation rates, crop damage, and yields each exhibited different responses across studies, sometimes increasing and sometimes decreasing in landscapes with more noncrop habitat but overall showing no consistent trend. Thus, models that used landscape-composition variables to predict pest-control dynamics demonstrated little potential to explain variation across studies, though prediction did improve when comparing studies with similar crop and landscape features. Overall, our work shows that surrounding noncrop habitat does not consistently improve pest management, meaning habitat conservation may bolster production in some systems and depress yields in others. Future efforts to develop tools that inform farmers when habitat conservation truly represents a win–win would benefit from increased understanding of how landscape effects are modulated by local farm management and the biology of pests and their enemies

An organic geochemical correlation study of some Drmno depresssion crude oils (southern part of the Pannonian Basin, Yugoslavia)

The results of an investigation of crude oils originating from the Sirakovo and Bradarac-Maljurevac localities (southern part of the Pannonian Basin) are reported in this paper. The aim was to estimate the organic geochemical similarity of the crude oils from the Drmno (Kostolac) depression oil fields. The nine selected samples originated from reservoir rocks of various depths. Reliable source and organic geochemical maturation parameters served as the basis for the correlation studies. The similar origin of the investigated Drmno depression crude oils was corroborated, characterized by a significant participation of terrestrial precursor biomass. They were shown to be of relatively low maturity and to have been formed during the earlier stages of the diagenet- ic-catagenetic sequence of processes leading to the formation of crude oils, most probably in source rocks ofTertiary age, corresponding to vitrinite reflectances between Ro = 0.70 % and Ro = 0.80 %. The crude oils from Bradarac-Maljurevac seemed to be somewhat less homogeneous with respect to organic geochemical parameters compared to Sirakovo crude oils

Chronic a1-adrenoreceptor blockade produces age-dependent changes in rat thymus structure and thymocyte differentiation

In order to examine the influence of chronic a1-adrenergic receptor (a1-AR) blockade on the thymus structure and T-cell maturation, peripubertal and adult male rats were treated with urapidil (0.20 mg/kg BW/d; s.c.) over 15 consecutive days. Thymic structure and phenotypic characteristics of the thymocytes were assessed by stereological and flow cytometry analysis, respectively. In immature rats, treatment with urapidil reduced the body weight gain and, affecting the volume of cortical compartment and its cellularity decreased the organ size and the total number of thymocytes compared to age-matched saline-injected controls. The percentage of CD4+8- single positive (SP) thymocytes was decreased, while that of CD4-8+ was increased suggesting, most likely, a disregulation in final steps of the positively selected cells maturation. However, a1- AR blockade in adult rats increased the thymus weight as a consequence of increase in the cortical size and cellularity. The increased percentage of most immature CD4-8- double negative (DN) cells associated with decreased percentage of immature CD4+8+ double positive (DP) thymocytes suggests a decelerated transition from DN to DP stage of T-cell development. As in immature rats, the treatment in adult rats evoked changes in the relative numbers of SP cells, but contrary to immature animals, favoring the maturation of CD4+8- over CD4-8+ thymocytes. These results demonstrate that: i) chronic blockade of a1-ARs affects both the thymus structure and thymocyte differentiation, ii) these effects are age-dependent, pointing out to pharmacological manipulation of a1-AR-mediated signaling as potential means for modulation of the intrathymic T-cell maturation