7,584 research outputs found
\u3cem\u3eThe Cherry Beret\u3c/em\u3e by Ashton L. Kerr [Review]
Review of Colonel Ashton L. Kerr, MD, The Cherry Beret: Distant recollections of World War II as remembered by one of the first Canloan officers. Published privately
Risk in agriculture as impediment to rural lending: the case of North-Western Kazakhstan
On the basis of portfolio selection theory, this paper finds that whole-farm risk must be regarded as a major reason for the low level of credit flow to agriculture in North-western Kazakhstan. A quadratic programming model was used in order (a) to demonstrate the comparatively high overall risk exposition of a typical farm, (b) to show that an inflow of working capital could contribute to risk reduction, and (c) to illustrate short-term risk management strategies. Although there may be a role for the government in reducing risk exposition of agriculture in its current form, natural and economic constraints suggest to pave the way for structural reforms that reduce the importance of agriculture in the rural economy. -- G E R M A N V E R S I O N: Auf Grundlage der Portfolio selection-Theorie kommt dieser Beitrag zu dem Ergebnis, dass das einzelbetriebliche Risiko in der Landwirtschaft Nordwest-Kasachstans als ein Hauptgrund für geringen Kreditzufluss angesehen werden muss. Ein quadratisches Programmierungsmodell wurde verwendet, um (a) die vergleichbar hohe Riskoexposition eines typischen Betriebes zu verdeutlichen, (b) zu zeigen, daß ein Zufluss von Umlaufkapital zur Risikoreduktion beitragen kann und (c) kurzfristige Risikomanagement-Strategien zu illustrieren. Obwohl es bestimmte Politikoptionen zur Verminderung des Risikos in der Landwirtschaft in ihrer gegenwärtigen Form gibt, legen natürliche und ökonomische Rahmenbedingungen tiefgreifendere Strukturreformen nahe. Diese sollten dazu beitragen, mittelfristig die Bedeutung der Landwirtschaft im ländlichen Raum zu verringern.Agricultural credit,Kazakhstan,Portfolio selection theory,Risk programming,Agrarkredit,Kasachstan,Portfolio selection-Theorie,Risiko-Programmierung
Tree-Automatic Well-Founded Trees
We investigate tree-automatic well-founded trees. Using Delhomme's
decomposition technique for tree-automatic structures, we show that the
(ordinal) rank of a tree-automatic well-founded tree is strictly below
omega^omega. Moreover, we make a step towards proving that the ranks of
tree-automatic well-founded partial orders are bounded by omega^omega^omega: we
prove this bound for what we call upwards linear partial orders. As an
application of our result, we show that the isomorphism problem for
tree-automatic well-founded trees is complete for level Delta^0_{omega^omega}
of the hyperarithmetical hierarchy with respect to Turing-reductions.Comment: Will appear in Logical Methods of Computer Scienc
Induction of defences and within-plant variation on palatability in two brown algae from the northern-central coast of Chile: effects of mesograzers and UV radiation
Macroalgae possess different defense mechanisms in response to herbivory. Some species produce anti-herbivore secondary metabolites, but production of these substances can be costly. Therefore, algae may produce defensive metabolites only in response to herbivory (inducible defense) or defend particular parts of the alga differentially (within-alga variation). In the present study, we examined whether two species of brown algae from the SE-Pacific show evidence of inducible chemical defense (non-polar compounds) or within-alga variation of defense, which we estimated in form of palatability of differently treated algae to amphipod grazers (with live algae and agar-based food containing non-polar algal extracts). In Glossophora kunthii (C. Agardh) J. Agardh, we observed an increase in palatability after algae were acclimated for 12 days without grazers. Subsequent addition of grazers for 12 days then resulted in a reduction of palatability indicating the existence of inducible defense. After removal of grazers for 12 days, these induced effects again disappeared. The reaction of G. kunthii was triggered even by the mere presence of grazers, which suggests that this alga can respond to waterborne cues by reducing palatability. Effects were only found for agar-based food containing non-polar extracts, but not for live algae, suggesting that some parts of the algae are undefended. Our second experiment on within-alga variation confirmed that only apical (growth region) and basal parts (near the holdfast region) of G. kunthii are defended against herbivores. For the second species, Macrocystis integrifolia Bory, the first experiment revealed no induction of defense, while the second experiment on within-alga variation showed that amphipods avoided basal parts and in particular stipes of M. integrifolia but only in live algae. Although both studied algal species differed substantially in their defensive strategies, their reaction was independent of the presence or absence of UV radiation. Thus, it appears that UV effects play only a minor role in anti-herbivore defense, which is in accordance with most previous studies
The Effect of Target Transparency on Managers’ Target Setting Decisions
This study investigates, via two experiments, the effects of target transparency, which reflects employees' knowledge about each other's targets in an organization, on managers' target setting decisions. We also investigate whether this effect depends on the need for help among employees. We predict and find that target transparency and need for help interact to influence managers' target setting decisions. Target transparency increases target levels when the need for help is low, but not when it is high. Further, target transparency leads managers to differentiate less between individual employee targets. This reduction is greater when the need for help is high than when it is low. Additional analyses support our theory by revealing that managers strategically set targets in a way that is consistent with an intention to motivate both effort at the individual level and help among employees when such are needed. Our results help explain anecdotal evidence of why companies that value help among employees often make targets transparent throughout the entire organization
Design and in vivo characterization of self-inactivating human and non-human lentiviral expression vectors engineered for streptogramin-adjustable transgene expression
Adjustable transgene expression is considered key for next-generation molecular interventions in gene therapy scenarios, therapeutic reprogramming of clinical cell phenotypes for tissue engineering and sophisticated gene-function analyses in the post-genomic era. We have designed a portfolio of latest generation self-inactivating human (HIV-derived) and non-human (EIAV-based) lentiviral expression vectors engineered for streptogramin-adjustable expression of reporter (AmySΔS, EYFP, SAMY, SEAP), differentiation-modulating (human C/EBP-α) and therapeutic (human VEGF) transgenes in a variety of rodent (CHO-K1, C2C12) and human cell lines (HT-1080, K-562), human and mouse primary cells (NHDF, PBMC, CD4+) as well as chicken embryos. Lentiviral design concepts include (i) binary systems harboring constitutive streptogramin-dependent transactivator (PIT) and PIT-responsive transgene expression units on separate lentivectors; (ii) streptogramin-responsive promoters (PPIR8) placed 5′ of desired transgenes; (iii) within modified enhancer-free 3′-long terminal repeats; and (iv) bidirectional autoregulated configurations providing streptogramin-responsive transgene expression in a lentiviral one-vector format. Rigorous quantitative analysis revealed HIV-based direct PPIR-transgene configurations to provide optimal regulation performance for (i) adjustable expression of intracellular and secreted product proteins, (ii) regulated differential differentiation of muscle precursor cell lines into adipocytes or osteoblasts and (iii) conditional vascularization fine-tuning in chicken embryos. Similar performance could be achieved by engineering streptogramin-responsive transgene expression into an autoregulated one-vector format. Powerful transduction systems equipped with adjustable transcription modulation options are expected to greatly advance sophisticated molecular interventions in clinically and/or biotechnologically relevant primary cells and cell line
Amiloride reduces portal hypertension in rat liver cirrhosis
Objective This study aimed to investigate the effect of amiloride on portal hypertension. Amiloride is known to inhibit Na(+)/H(+) exchangers on activated hepatic stellate cells. Methods Liver cirrhosis in rats was induced by bile duct ligation (BDL) or thioacetamide (TAA) administration. The effects of zymosan for Kupffer cell (KC) activation or a thromboxane (TX) analogue (U46619) were tested in isolated perfused livers of cirrhotic rats and in vivo. Downstream mechanisms were investigated using Rho kinase inhibitor (Y-27632) or amiloride. Acute and chronic effects of amiloride and canrenoate on portal pressure were compared in perfused livers and in vivo. TXB(2) efflux was measured by ELISA. The phosphorylation state of moesin (p-moesin) as an indicator of Rho kinase activity and expression of the thromboxane synthase were assessed by western blot analyses. The activity of hepatic stellate cells was analysed by western blot and staining for alpha-smooth muscle actin (alpha-SMA). Results In BDL rats, KC activation via zymosan increased portal pressure. This was attenuated by the Rho kinase inhibitor Y-27632. Increased thromboxane efflux following zymosan infusion remained unaltered by Y-27632. The infusion of amiloride attenuated zymosan- and U46619-induced increases in portal perfusion pressure. In vivo, direct administration of amiloride, but not of canrenoate, lowered portal pressure. In TAA and BDL rats, treatment with amiloride for 3 days reduced basal portal pressure and KC-induced increases in portal pressure whereas canrenoate had no effect. In livers of amiloride-treated animals, the phosphorylation state of moesin and the number of alpha-SMA positive cells were reduced. Conclusions Amiloride lowers portal pressure in rat liver cirrhosis by inhibition of intrahepatic vasocontraction. Therefore, patients with cirrhosis and portal hypertension may benefit from amiloride therapy
Hormônios sexuais influenciam a resposta ao trauma e à sepsis: possíveis soluções terapêuticas
Uma série de estudos clínicos e experimentais demonstram a existência de dimorfismo sexual das respostas imunológicas e orgânicas, bem como da suscetibilidade e morbidade em relação ao choque, ao trauma e à sepse. Respostas imunes celularmente mediadas apresentam-se deprimidas em machos em resposta ao binômio trauma-hemorragia, mas conservados/enaltecidos em fêmeas em proestro. Adicionalmente demonstra-se que os hormônios sexuais são responsáveis por esta dicomotomia de resposta sexualmente específica, em condições cardiovasculares adversas. Estudos específicos indicam que os andrógenos produzem imunodepressão pós-trauma hemorragia em machos. Em contraste, esteróides sexuais femininos parecem exibir propriedades imunoprotetoras após episódios de trauma com ou sem perda importante de sangue. No terreno dos mecanismos subjacentes, foram identificados receptores para hormônios sexuais em várias células do sistema imunológico, sugerindo a existência de efeitos diretos destes hormônios sobre tais células. Alternativamente, observam efeitos indiretos de hormônios sexuais tais como modulação das respostas cardiovasculares das enzimas sintetizadores de andrógeno e estrógeno, que podem contribuir para as estas respostas sexualmente diferenciadas. Estudos recentes indicam que os hormônios sexuais, como por exemplo a dehidroepiandrosterona também modulam a função de células mononucleares da série branca em pacientes cirúrgicos. Assim, as propriedades imunomodulatórias de hormônios sexuais/antagonistas de receptores/enzimas sintetizadores de esteróides após a ocorrência de trauma ou de hemorragia sugerem o caminho para novas estratégias terapêuticas para o tratamento de imunodepressão em pacientes cirúrgicos.Several clinical and experimental studies have demonstrated gender dimorphism in immune and organ responsiveness and in the susceptibility to and morbidity from shock, trauma, and sepsis. In this respect, cell-mediated immune responses have been shown to be depressed in males following trauma-hemorrhage, whereas they were aintained/enhanced in proestrus females. Furthermore, sex hormones have been shown to be responsible for this gender-specific immune response following adverse circulatory conditions. More specifically, studies indicate that androgens produce immunodepression following trauma-hemorrhage in males. In contrast, female sex steroids appear to exhibit immunoprotective properties following trauma and severe blood loss. With regard to the underlying mechanisms, receptors for sex hormones have been identified on various immune cells suggesting direct effects of these hormones on the immune cells. Alternatively, indirect effects of sex hormones, ie, modulation of cardiovascular responses or androgen- and estrogen-synthesizing enzymes, might contribute to gender-specific immune responses. Recent studies indicate that sex hormones, eg, dehydroepiandrosterone (DHEA), also modulate the function of peripheral blood mononuclear cells in surgical patients. Thus, the immunomodulatory properties of sex hormones/receptor antagonists/sex steroid synthesizing enzymes following trauma-hemorrhage suggests novel therapeutic strategies for the treatment of immunodepression in surgical patients
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