6 resultados para activities of dean
em Digital Commons at Florida International University
Resumo:
It is well established that secondary metabolites play an important role in plant chemical defense. In an effort to find natural herbicides research on plant growth regulatory activity of secondary metabolites has received more and more attention recently. The genus Piper has been an important source for useful secondary metabolites.^ Crude extracts from Piper species inhibited gram-positive bacteria and higher plant growth under laboratory conditions. Bioassay-guided isolation and purification lead to the identification of safrole, a phenylpropene, as the responsible agent for the inhibitory activity. Safrole was found to leach from naturally fallen leaves with water. Mechanisms of plant growth inhibition by safrole were investigated. Disassociation of cell membrane from cell walls was determined to be a major cause.^ Phenylpropenes structurally similar to safrole had similar phytogrowth inhibitory activity. It is postulated that phenylpropanoids are an important group of naturally occurring secondary metabolites in plant-plant interactions. ^
Resumo:
Twelve plants used medicinally in Callejon de Huaylas, Department of Ancash, northeastern Peru were selected and screened in vitro for cytotoxic and cytostatic activities. Traditional preparations, aqueous extracts and organic extracts (methanol:dimethyl chloride) were tested against murine leukemia P388 cells using flow cytometry. Seventy-five percent or more of the traditional and aqueous extracts were cytostatic at concentrations of 1mg/ml. For organic extracts, cytostatic activity ranged from 8.3% (at 6.25 μg/ml) to 58.3% (at 100 μg/ml). Quinchamalium procumbens, Ophryosporus chilca and Baccharis genistelloides showed strong activity. Extracts of Brachyotum rostratum, Monnina salicifolia, and Orthrosanthus chimboracensis were particularly interesting, since they were cytostatic but not cytotoxic at concentrations of 0.5 mg/ml. These Andean plants merit further analysis. The high percentage of activity found among the traditional preparations suggests that the traditional medical knowledge of Callejon de Huaylas healers deserves respect and merits further research. ^
Resumo:
The growth of criminal gangs and organized crime groups has created unprecedented challenges in Central America. Homicide rates are among the highest in the world, countries spend on average close to 10 percent of GDP to respond to the challenges of public insecurity, and the security forces are frequently overwhelmed and at times coopted by the criminal groups they are increasingly tasked to counter. With some 90 percent of the 700 metric tons of cocaine trafficked from South America to the United States passing through Central America, the lure of aiding illegal traffickers through provision of arms, intelligence, or simply withholding or delaying the use of force is enormous. These conditions raise the question: to what extent are militaries in Central America compromised by illicit ties to criminal groups? The study focuses on three cases: Nicaragua, El Salvador, and Honduras. It finds that: Although illicit ties between the military and criminal groups have grown in the last decade, militaries in these countries are not yet “lost’ to criminal groups. Supplying criminal groups with light arms from military stocks is typical and on the rise, but still not common. In general the less exposed services, the navies and air forces, are the most reliable and effective ones in their roles in interdiction. Of the three countries in the study, the Honduran military is the most worrying because it is embedded in a context where civilian corruption is extremely common, state institutions are notoriously weak, and the political system remains polarized and lacks the popular legitimacy and political will needed to make necessary reforms. Overall, the armed forces in the three countries remain less compromised than civilian peers, particularly the police. However, in the worsening crime and insecurity context, there is a limited window of opportunity in which to introduce measures targeted toward the military, and such efforts can only succeed if opportunities for corruption in other sectors of the state, in particular in law enforcement and the justice system, are also addressed. Measures targeted toward the military should include: Enhanced material benefits and professional education opportunities that open doors for soldiers in promising legitimate careers once they leave military service. A clear system of rewards and punishments specifically designed to deter collusion with criminal groups. More effective securing of military arsenals. Skills and external oversight leveraged through combined operations, to build cooperation among those sectors of the military that have successful and clean records in countering criminal groups, and to expose weaker forces to effective best practices.
Resumo:
Over the last decade, the Colombian military has successfully rolled back insurgent groups, cleared and secured conflict zones, and enabled the extraction of oil and other key commodity exports. As a result, official policies of both the Uribe and Santos governments have promoted the armed forces to participate to an unprecedented extent in economic activities intended to consolidate the gains of the 2000s. These include formal involvement in the economy, streamlined in a consortium of military enterprises and social foundations that are intended to put the Colombian defense sector “on the map” nationally and internationally, and informal involvement expanded mainly through new civic action development projects intended to consolidate the security gains of the 2000s. However, failure to roll back paramilitary groups other than through the voluntary amnesty program of 2005 has facilitated the persistence of illicit collusion by military forces with reconstituted “neoparamilitary” drug trafficking groups. It is therefore crucially important to enhance oversight mechanisms and create substantial penalties for collusion with illegal armed groups. This is particularly important if Colombia intends to continue its new practice of exporting its security model to other countries in the region. The Santos government has initiated several promising reforms to enhance state capacity, institutional transparence, and accountability of public officials to the rule of law, which are crucial to locking in security gains and revitalizing democratic politics. Efforts to diminish opportunities for illicit association between the armed forces and criminal groups should complement that agenda, including the following: Champion breaking existing ties between the military and paramilitary successor groups through creative policies involving a mixture of punishments and rewards directed at the military; Investigation and extradition proceedings of drug traffickers, probe all possible ties, including as a matter of course the possibility of Colombian military collaboration. Doing so rigorously may have an important effect deterring military collusion with criminal groups. Establish and enforce zero-tolerance policies at all military ranks regarding collusion with criminal groups; Reward military units that are effective and also avoid corruption and criminal ties by providing them with enhanced resources and recognition; Rely on the military for civic action and development assistance as minimally as possible in order to build long-term civilian public sector capacity and to reduce opportunities for routine exposure of military forces to criminal groups circulating in local populations.