Biphasic effect of a primary tumor on the growth of secondary tumor implants Bruzzo Iraola, Juan; Chiarella, Paula; Meissl, Roberto Jose; Ruggiero, Raul Alejandro Background: The phenomenon of hormesis is characterized by a biphasic dose-response, exhibiting opposite effects in the low- and high-dose zones. In this study, we explored the possibility that the hormesis concept may describe the interactions between two tumors implanted in a single mouse, such that the resulting tumors are of different sizes. Materials and methods: We used two murine tumors of spontaneous origin and undetectable immunogenicity growing in BALB/c mice. A measure of cell proliferation was obtained by immunostaining for Ki-67 protein and by using the [3H] thymidine uptake assay. For serum fractionation, we utilized dialysis and chromatography on Sephadex G-15. Results: The larger primary tumor induced inhibitory or stimulatory effects on the growth of the smaller secondary one, depending on the ratio between the mass of the larger tumor relative to that of the smaller one, with high ratios rendering inhibition and low ratios inducing stimulation of the secondary tumor. Conclusion: Since metastases can be considered as natural secondary tumor implants in a tumor-bearing host and that they constitute the main problem in cancer pathology, the use of the concept of hormesis to describe those biphasic effects might have significant clinical implications. In effect, if the tumor-bearing host were placed in the inhibitory window, tumor extirpation could enhance the growth of distant metastases and, reciprocally, if placed in the stimulatory window, tumor extirpation would result not only in a reduction or elimination of primary tumor load but also in a slower growth or inhibition of metastases. © 2010 Springer-Verlag.

Costs and Benefits of Radio-collaring on the Behavior, Demography, and Conservation of Owl Monkeys (Aotus azarai) in Formosa, Argentina Juárez, Cecilia Paola; Rotundo, Marcelo Alejandro; Berg, Wendy; Fernandez Duque, Eduardo The benefits to researchers of capturing and collaring free-ranging primates are numerous, but so are the actual and potential costs to the individuals. We aimed to 1)evaluate quantitatively the possible demographic long-term costs of radio-collaring a free-ranging primate species, and 2) evaluate qualitatively the costs to the subjects and the overall benefits to the research program that results from monitoring a large number of groups with collared individuals during many years. Between 2000 and 2009, we captured, recaptured, and radio-collared 146 owl monkeys (Aotus azarai) to study the behavior, demography, and genetics of the species. To evaluate the potential long-term costs of the collaring procedures on the population, we compared the demographic composition of groups (n=20) in our core study area with those of undisturbed groups(n=20) in a control area within the same forest. Groups in both areas ranged in size between 2 and 5 individuals. Surprisingly, group size tended to be larger among the study groups owing to more infants and juveniles in those groups than in the control groups. The benefits to the research program have included, among others, the reliable identification of individuals, increased sample sizes, the recovery of specimens, studies of dispersal, outreach activities, and conservation education. Still, some of the benefits will become tangible only when the project persists on time; is fully approved and supported by local authorities; and has broad community participation, as well as conservation and education goals. Thus, any serious initiative to capture and collar individuals should be the result of an extremely careful evaluation of benefits and costs.

Ensayo y error: la reconversión de las estrategias empresariales en la disputa política en el espacio de trabajo : Metrovías y el Cuerpo de delegados de Subterráneos de Buenos Aires Ventrici, Patricia Para comprender la dinámica del desarrollo de la organización gremial es imprescindible dar cuenta de la relación siempre dinámica entre la dominación y la resistencia en el espacio de trabajo. La organización de los trabajadores y la corporación empresarial componen un vínculo estructuralmente contradictorio, en el que las acciones de cada parte condicionan y moldean el accionar de la otra, y en el que el objetivo de fondo es conservar la iniciativa política para ganar terreno en la disputa por el control del espacio de trabajo. Desde esta perspectiva, nuestro trabajo se propone aproximarse a la comprensión de la dinámica y transformaciones de la dominación social en un proceso micro, analizando las reconversiones de las estrategias empresariales en función de los acontecimientos políticos generados desde la práctica sindical al interior de la empresa Metrovías, concesionaria del transporte subterráneo en la Ciudad de Buenos Aires. Creemos que dicho caso reúne un conjunto de particularidades que dan cuenta de su potencialidad para reflexionar en torno a esta problemática, en la medida en que tiene lugar al interior de un tipo de empresa privatizada paradigmático de los cambios en las relaciones del trabajo en las últimas décadas, a la vez que se trata de un sector cuya organización sindical ha sido particularmente exitosa en las luchas por sus reivindicaciones. Frente al avance de estos procesos reivindicativos, a lo largo de los años, la empresa ha ido desarrollando distintas estrategias para contrarrestar la incidencia de la organización colectiva, que abarcaron desde políticas de coerción directa hasta técnicas orientadas a la fidelización e implicación afectiva de los trabajadores. Precisamente serán las causas, modos y consecuencias de estas transformaciones el objeto privilegiado de nuestra indagación.; To understand the dynamics of development of the trade organization is imperative to always realize the relationship dynamics between domination and resistance in the workspace. The organization of workers and business corporation comprise a structurally adversarial relationship in which each party shares condition and shape the actions of the other and in which the basic aim is to retain the political initiative to gain ground in the dispute over control of the workspace. From this perspective, our paper proposes closer to understanding the dynamics and transformations of social domination in a micro process, analyzing the restructuring of corporation strategies based on political events stemming from labor practice within the company Metrovías, licensee of the subway system in Buenos Aires. We believe that this case meets a set of characteristics that account for its potential to reflect on this issue, as it takes place within a kind of privatized company paradigmatic changes in labor relations in the past decades, while this is a sector whose union has been particularly successful in fighting for their claims. Encroachment of these reintegration process, over the years, the company has developed various strategies to counteract the impact of collective organization, ranging from direct coercion policies oriented techniques to the loyalty and emotional involvement of workers. It will be the causes, modes and consequences of these changes the privileged object of our inquiry.

The expression of Sphingosine kinase-1 in head and neck carcinoma Facchinetti, Maria Marta; Gandini, Norberto Ariel; Fermento, María Eugenia; Sterin, Norma Beatriz; Ji, Youngmi; Patel, Vyomesh; Gutkind, J. Silvio; Rivadulla, Maria G.; Curino, Alejandro Carlos Sphingosine kinase-1 (SPHK1) modulates the proliferation, apoptosis and differentiation of keratinocytes through the regulation of ceramide and sphingosine-1-phosphate levels. However, studies on the expression of SPHK1 in human head and neck squamous cell carcinoma (HNSCC) specimens are lacking. Therefore, the aim of the present work was to evaluate SPHK1 expression in human primary HNSCCs and to correlate the results with clinical and anatomopathological parameters. We investigated the expression of this protein by immunohistochemistry performed in tissue microarrays of HNSCC and in an independent cohort of 37 paraffin-embedded specimens. SPHK1 expression was further validated by real-time PCR performed on laser capture-microdissected tissue samples. The positive rate of SPHK1 protein in the cancerous tissues was significantly higher (74%) than that in the nontumor oral tissues (23%), and malignant tissues showed stronger immunoreactivity for SPHK1 than normal matching samples. These results were confirmed by real-time PCR quantification of SPHK1 mRNA. Interestingly, the positive expression of SPHK1 was associated with shorter patient survival time (Kaplan-Meier survival curves) and with the loss of p21 expression. Taken together, these results demonstrate that SPHK1 is upregulated in HNSCC and provide clues of the role SPHK1 might play in tumor progression.

Animal models in diabetes and pregnancy Jawerbaum, Alicia Sandra; White, Verónica The worldwide increase in the incidence of diabetes, the increase in type 2 diabetes in women at reproductive ages, and the cross-generation of the intrauterine programming of type 2 diabetes are the bases for the growing interest in the use of experimental diabetic models in order to gain insight into the mechanisms of induction of developmental alterations in maternal diabetes. In this scenario, experimental models that present the most common features of diabetes in pregnancy are highly required. Several important aspects of human diabetic pregnancies such as the increased rates of spontaneous abortions, malformations, fetoplacental impairments, and offspring diseases in later life can be approached by using the appropriate animal models. The purpose of this review is to give a practical and critical guide into the most frequently used experimental models in diabetes and pregnancy, discuss their advantages and limitations, and describe the aspects of diabetes and pregnancy for which these models are thought to be adequate. This review provides a comprehensive view and an extensive analysis of the different models and phenotypes addressed in diabetic animals throughout pregnancy. The review includes an analysis of the surgical, chemical-induced, and genetic experimental models of diabetes and an evaluation of their use to analyze early pregnancy defects, induction of congenital malformations, placental and fetal alterations, and the intrauterine programming of metabolic diseases in the offspring’s later life.

Climate-driven changes in air quality over Europe by the end of the 21st century, with special reference to Portugal Carvalho, A.; Monteiro, A.; Solman, Silvina Alicia; Miranda, A. I.; Borrego, C. Climate change alone may deeply impact air quality levels in the atmosphere because the changes in the meteorological conditions will induce changes on the transport, dispersion and transformation of air pollutants. The aim of this work was to evaluate the impact of climate change on the air quality over Europe and Portugal, using a reference year (year 1990) and a IPCC SRES A2 year (year 2100). The Hadley Centre global atmospheric circulation model (HadAM3P) was used to provide results for these two climatic scenarios, which were then used as synoptic forcing for the MM5-CHIMERE air quality modelling system. In order to assess the contribution of future climate change on O3 and PM concentrations, no changes in regional emissions were assumed and only climate change forcing was considered. The modelling results suggest that the O3 monthly mean levels in the atmosphere may increase almost 50 mg m3 across Europe in July under the IPCC SRES A2 scenario. In Portugal, this increase may reach 20 mg m3 . The changes of PM10 monthly average values over Europe will depend on the region. The increase in PM10 concentrations during specific months could be explained by the average reduction of the boundary layer height and wind speed.

Assessment of the impact of 2,4-dichlorophenoxyacetic acid (2,4-D) on indigenous herbicide-degrading bacteria and microbial community function in an agricultural soil Zabaloy, Maria Celina; Garland, Jay L.; Gómez, Marisa Anahi The herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) may influence soil microbial communities by altering the balance between resident populations. Our objective was to assess the effect of environmentally relevant levels (ERLs) of 2,4-D on microbial community function and on the population dynamics of 2,4-D degrading bacteria using a microcosm approach. The most probable number approach was used to enumerate 2,4-D-degrading soil bacteria. Carbon substrates utilization was tested with a microtiter-based oxygen sensor system to evaluate short-term functional shifts caused by herbicide treatment. Shifts in the community in response to potential toxicity of 2,4-D were assessed in the agricultural soil and a reference forest soil using the pollution-induced community-tolerance (PICT) approach. Results indicated that the agricultural soil had a stable 2,4-D degrading population able to use the herbicide as C and energy source, which increases immediately after an ERL dose of 2,4-D and remains high for about 1 month after exposure has ceased. An enhanced, dose-dependent response to 2,4-D as substrate was observed in the microtiter assay, while heterotrophic bacterial activity appeared mostly unchanged. The PICT assay showed higher tolerance to 2,4-D in the agricultural soil than in the unexposed forest soil. Our results suggest that agricultural use of 2,4-D at recommended level leads to selection for (1) a copiotrophic degrader population and (2) a persistently herbicide-tolerant, but functionally similar, microbial community.

Effect of steviosides and system composition on stability and antimicrobial action of sorbates in acidified model aqueous systems Hracek, V. M.; Gliemmo, María Fernanda; Campos, Carmen Adriana The effect of steviosides on sorbate stability and on its antimicrobial action was studied in aqueous systems (pH 3.0). The use of steviosides decreased sorbate destruction in all the systems. Its effect on nonenzymatic browning (NEB) depended on the system composition. From the point of view of microbial stability, the steviosides promoted a slight increase in the minimum inhibitory concentration (MIC) of sorbates against Zygosaccharomyces bailii and Zygosaccharomyces rouxii. However, the main effect of steviosides was the protected action on sorbate destruction. This action was essential to ensure that the preservative residual level was higher than the MIC of the preservative to prevent the growth Z. bailii or Z. rouxii during storage. The results reported highlight that the use of steviosides in aqueous model systems resembling low-calorie sweet products can be useful to protect potassium sorbate (KS) from destruction and depending on the system composition also to decrease browning development.

Casimir energy between media-separated cylinders: the scalar case Lombardo, Fernando Cesar; Mazzitelli, Francisco Diego; Villar, Paula Ines; Dalvit, A. R. We derive exact expressions for the Casimir scalar interaction energy between media-separated eccentric dielectric cylinders and for the media-separated cylinder-plane geometry using a mode-summation approach. Similarly to the electromagnetic Casimir-Lifshitz interaction energy between fluid-separated planar plates, the force between cylinders is attractive or repulsive depending on the relative values of the permittivities of the three intervening media.

High rates of bovine blastocyst development after ICSI-mediated gene transfer assisted by chemical activation Bevacqua, Romina Jimena; Pereyra Bonnet, Federico Alberto; Fernandez Martin, Rafael; Salamone, Daniel Felipe In order to establish conditions for intracytoplasmic sperm injection-mediated gene transfer (ICSI-MGT) in cattle, various aspects of fertilization and embryonic development were assessed after five activation treatments. Spermatozoa were co-incubated with pCX-EGFP (pCX-enhanced green fluorescent protein gene) plasmid and injected into metaphase II oocytes, which were then treated with ionomycin (Io), before further activation with the following agents: 6-dimethylaminopurine (Io-DMAP), additional Io plus DMAP (2Io-DMAP), Io alone (2Io), ethanol (Io-EtOH), or strontium chloride (Io-SrCl2). Fertilization rates at 16 h after ICSI, presence of a condensed spermatozoon head on Day 4 (Day 0 = ICSI), blastocyst and EGFP expression rates on Day 7, and Oct-4 pattern of Day 8 blastocysts were evaluated. Fertilization rates did not differ significantly among treatments. All (100%) of EGFP-positive embryos resulted from ICSI fertilization, whereas at least 60% of EGFP-negative embryos (>4 cells) had a condensed sperm head. Blastocyst rates after 2Io-DMAP were not significantly different from Io-DMAP or Io-EtOH, but they were higher than 2Io or Io-SrCl2 treatments (25.9, 18.7, 14.7, 9.4, and 10.9% respectively; P < 0.05). Transgene expression rates were higher for Io-DMAP, 2Io-DMAP and Io-SrCl2 than for 2Io and Io-EtOH (52.3, 53.0, 42.8, 28.2, and 29.4% respectively; P < 0.05). Over 80% of the blastocysts expressed egfp protein. In conclusion, ICSI-MGT was a powerful technique to produce bovine embryos that expressed the EGFP transgene. Moreover, the actual efficiency of ICSI-MGT could be readily evaluated by this method, which uses a marker expressed early in embryo development.

Chronic cannulation in the small intestine of feral pigeons (Columba livia) to assess bioavailability Chediack, Juan Gabriel; Cid, Fabricio Damian; Fasulo, S. V.; Caviedes Vidal, Enrique Juan Raul We improved a method of chronic duodenal cannulation to study intestinal transport of solutes in an in vivo model (pigeon, Columba livia). A hypoallergenic cannula was inserted into the proximal part of the small intestine of pigeons and used for solution administration. Recovery from surgery was extremely rapid and animals started eating and drinking within a day. After surgery, the body mass of cannulated pigeons was stable, and no adverse effects in the weight could be detected. The method is simple, economical and useful to determine intestinal bioavailability of solutes, for nutritional and ecological studies, in intact animals without influence of anesthesia.

Nitric oxide synthase-like dependent NO production enhances heme oxygenase up-regulation in ultraviolet-B-irradiated soybean plants Santa Cruz, Diego Mario; Pacienza, Natalia Alejandra; Polizio, Ariel Héctor; Balestrasse, Karina Beatriz; Tomaro, Maria Lujan; Yannarelli, Gustavo Gabriel Heme oxygenase (HO) has antioxidant properties and is up-regulated by reactive oxygen species (ROS) in ultraviolet-B-irradiated soybean plants. This study shows that nitric oxide (NO) protects against oxidative damage and that nitric oxide synthase (NOS)-like activity is also required for HO-1 induction under UV-B radiation. Pre-treatments with sodium nitroprussiate (SNP), a NO-donor, prevented chlorophyll loss, H2O2 and View the MathML source accumulation, and ion leakage in UV-B-treated plants. HO activity was significantly enhanced by NO and showed a positive correlation with HO-1 transcript levels. In fact, HO-1 mRNA levels were increased 2.1-fold in 0.8 mM SNP-treated plants, whereas subsequent UV-B irradiation augmented this expression up to 3.5-fold with respect to controls. This response was not observed using ferrocyanide, a SNP inactive analog, and was effectively blocked by 2-(4-carboxyphenil)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO), a specific NO-scavenger. In addition, experiments carried out in the presence of NG-nitro-l-arginine methyl ester (l-NAME) or tungsten, well-known inhibitors of NOS and nitrate reductase, showed that NOS is the endogenous source of NO that mediates HO-1 expression. In summary, we found that NO is involved in the signaling pathway leading to HO-1 up-regulation under UV-B, and that a balance between NO and ROS is important to trigger the antioxidant response against oxidative stress.

Role of polymorphisms 919A>G and 2039A>G of FSH receptor (FSHR) gene in premature ovarian failure (POF) development Sundblad, Victoria; Chiauzzi, Violeta Alicia; Andreone, Luz; Campo, Stella Maris; Charreau, Eduardo Hernan; Dain, Liliana Beatriz Although the impact of polymorphisms 919A>G and 2039A>G of FSHR gene in normal ovarian function is almost clear, in Premature Ovarian Failure (POF) it still remains elusive. To analyse the putative association of these polymorphisms with POF development, 97 POF patients and 72 women over 40 years of age with normal menstrual record were genotyped for 919A>G and 2039A>G variants. No association was found between genotype GG of each polymorphism and the risk of POF. Nevertheless, ten POF patients and only one control presented the less common combinations 919G-2039A and 919A-2039G (p<0.05). In addition, the frequency of primary amenorrhoea and the occurrence of familial POF were significantly increased among patients with 919GG-2039GG genotype. In 45 normally menstruating women, no significant differences were found among different FSHR genotypes in FSH, E2, Inhibin A and Inhibin B levels. In conclusion, FSHR polymorphism genotypes were not associated either to the risk of POF or to serum hormone levels of control women. However, 919GG-2039GG genotype might be associated to relatively more severe symptoms of POF. On the other hand, the differences found between controls and patients in the prevalence of the cross haplotypes, may suggest that these rare allelic variants might possibly influence POF development.

Histamine receptors and cancer pharmacology Medina, Vanina Araceli; Rivera, Elena S. Considerable evidence has been collected indicating that histamine can modulate proliferation of different normal and malignant cells. High histamine biosynthesis and content together with histamine receptors have been reported in different human neoplasias including melanoma, colon and breast cancer, as well as in experimental tumours in which histamine has been postulated to behave as an important paracrine and autocrine regulator of proliferation. The discovery of the human histamine H(4) receptor in different tissues has contributed to our understanding of histamine role in numerous physiological and pathological conditions revealing novel functions for histamine and opening new perspectives in histamine pharmacology research. In the present review we aimed to briefly summarize current knowledge on histamine and histamine receptor involvement in cancer before focusing on some recent evidence supporting the novel role of histamine H(4) receptor in cancer progression representing a promising molecular target and avenue for cancer drug development.

Phenolic compounds from Pterocaulon alopecuroides Alarcón, Silvia Rosana; Pacciaroni, Adriana del Valle; Peñaloza, Lidia; Uriburu Monasterio, Maria Laura; Boemo, Analía; Sosa, Virginia Estela Aerial parts of Pterocaulon alopecuroides (Lam.) DC. (Asteraceae), were collected at the flowering stage in December 2003 in Salta, Argentina. The identification was carried out by Ing. Julio Tolaba. A voucher specimen (n° 3399) is on deposit at the Museo de la Facultad de Ciencias Naturales, Universidad Nacional de Salta, Salta, Argentina.

The symmetric Radon-Nikodým property for tensor norms Carando, Daniel Germán; Galicer, Daniel Eric We introduce the symmetric-Radon-Nikodým property (sRN pr operty) for finitely generated s-tensor norms β of order n and prove a Lewis type theorem for s-tensor norms with this property. As a consequence, if β is a projective s-tensor norm with the sRN prop- erty, then for every Asplund space E , the canonical map e ⊗ n,s β E ′ → e ⊗ n,s β ′ E ′ is a metric surjection. This can be rephrased as the isometric isomorph ism Q min ( E ) = Q ( E ) for certain polynomial ideal Q . We also relate the sRN property of an s-tensor norm with the A splund or Radon-Nikodým properties of different tensor products. S imilar results for full tensor products are also given. As an application, results concern ing the ideal of n -homogeneous extendible polynomials are obtained, as well as a new proof o f the well known isometric isomorphism between nuclear and integral polynomials on As plund spaces.

Algunas aclaraciones acerca del articulo “Linajes parentales amerindios en poblaciones del norte de Córdoba” (García A, Demarchi DA, Rev. Arg. Antrop. Biol. 8(1):57-71, 2006) Demarchi, Dario; García, Angelina En un número anterior de esta revista se publicó el artículo "Linajes parentales amerindios en poblaciones del norte de Córdoba" (García y Demarchi, 2006). En ese estudio se investigó la composición genética de una muestra de habitantes "criollos" de dos poblaciones del norte de Córdoba, a través del análisis de los marcadores del ADN mitocondrial que determinan los 4 principales linajes maternos amerindios y el marcador M3, del cromosoma Y, diagnóstico de linaje paterno amerindio. Se determinó la proporción de los linajes (haplogrupos) amerindios que sobreviven en esas localidades, se puso a prueba la existencia de  posibles variaciones significativas en la distribución de linajes entre ambas muestras y, por último, se establecieron similitudes con otros pueblos originarios del Cono Sur en la distribución de linajes maternos nativos. En el presente número, los lectores de la RAAB encontrarán una nota que se propone descalificar nuestro estudio a través de una serie de críticas. No es nuestro objetivo responder puntualmente a cada una de ellas sino más bien echar luz sobre algunas dudas que puedan surgir en los lectores a partir de las mismas.

The effect of the hydrocarbon-water interface structure on the behavior of an emulsion stabilized with dodecanephosphonic acid Verdinelli, Valeria; Messina, Paula Verónica; Schulz, Eduardo Nicolás; Salinas, Daniel Ricardo; Vuano, Bruno Mario; Schulz, Pablo Carlos We studied the phase transition of petroleum ether/water/n-dodecanephosphonic acid (DPA) from W/O to W/O/W emulsion when the neutralization degree (nd) of dodecanephosphonic acid (DPA) with NaOH was changed. We concluded that a phase transition from W/O emulsion to W/O/W emulsion occurs when nd≈0.47 due to a change in the structure of the polar layer at the oil/water interface from a tightly hydrogen-bonded layer to a less compact layer formed by -PO3H2 and -PO3H- groups in favor of an inversion. The W/O/W emulsion is probably caused by a partition of acid molecules in the water droplets interface inside the oil droplets, and monosodium phosphonate molecules at the external interface of oil droplets.

The unexpected diet of breeding Imperial Shags (Phalacrocorax atriceps) at the Nahuel Huapi Lake, Patagonia: implications on population trends? Casaux, Ricardo Jorge; Bertolin, María Lila; Tartara, Maria Alejandra; Alarcón, Pablo Angel Eduardo; Porro, Gerardo The Imperial Shag Phalacrocorax atriceps is widely distributed along the coast of South America and in Malvinas/Falkland Islands(Orta 1992). This shag is marine in most its range and forages predominantly on fish, although invertebrates were frequently reported as present in the diet(e.g., Punta etal. 2003, Ferrari et al. 2004, Bulgarella et al.2008)Reynolds (1934) reported the presence of the Imperial Shag breeding at Yehuin Lake,Tierra del Fuego, and later on Pereyra (1945, quoted in Navas 1970), Chebez & Gómez (1988) and Rasmussen et al. (1992) reported the existence of the only other three populations of this shag breeding in freshwater environments,the Nahuel Huapi (NHL),Fagnano, and Vintter lakes, respectively. Despite the potential interest in studying these populations, few studies provided information on the biology of this shag species. Although not globally threatened, the Imperial Shag at NHL is locally endangered and between the summers of 1990 (Rasmussen et.al. 1993) and 2005 (Pastore et al. 2005)the total number of individuals decreased in 68%. Thus,the aim of this study is provide the first information on the diet of the Imperial Shag breeding at NHL to improve the knowledge of the foraging behavior of this species as well as to explore the linkage between diet composition and the reported declining trend of this population.

La ciénaga afgana y la responsabilidad estadounidense Cuadro, Mariela El artículo analiza la actuación de las fuerzas de seguridad estadounidenses en Afganistán. A tal fin, se detiene en las distintas tácticas en juego en las esferas de poder en Washington. Detecta, entonces, un retorno al tratamiento hostil a los civiles afganos, produciéndose, entonces, una espiral que, se concluye, amenaza con transformarse en una guerra infinita.