A multiperiod model for production planning and design in a multiproduct batch environment Moreno, Marta Susana; Montagna, Jorge Marcelo A general multiperiod model to optimize simultaneously production planning and design decisions applied to multiproduct batch plants is proposed. This model includes deterministic seasonal variations of costs, prices, demands and supplies. The overall problem is formulated as a mixed-integer linear programming model by applying appropriate linearizations of non-linear terms. The performance criterion is to maximize the net present value of the profit, which comprises sales, investment, inventories, waste disposal and resources costs, and a penalty term accounting for late deliveries. A noteworthy feature of this approach is the selection of unit dimensions from the available discrete sizes, following the usual procurement policy in this area. The model simultaneously calculates the plant structure (parallel units in every stage, and allocation of intermediate storage tanks), and unit sizes, as well as the production planning decisions in each period (stocks of both product and raw materials, production plans, policies of sales and procurement, etc.).

Cambios ambientales y arqueología en el actual territorio del Uruguay Bracco Boksar, Roberto; del Puerto, Laura; Castiñeira Latorre, Carola; Garcia Rodriguez, Felipe; Panario, Daniel; Inda, Hugo Los cambios ambientales han ocupado un lugar central en la arqueología del Uruguay a partir de las investigaciones desarrolladas en la cuenca de la Laguna Merín, induciendo desarrollos técnico-metodológicos específicos. Este trabajo expone los resultados alcanzados a partir de los registros obtenidos de testigos de fondos de lagunas, particularmente el registro silicofitolítico. Los índices de humedad y temperatura se obtuvieron a partir de la relación de células chloridoides con el total de células cortas de gramíneas C4 y considerando las fluctuaciones de los fitolitos pooides. Los fitolitos chloridoides se producen en gramíneas C4, predominantes en regiones cálidas, áridas a semiáridas o con marcada estacionalidad en las precipitaciones. Las fluctuaciones de los fitolitos pooides, producidas por gramíneas C3, predominantes en zonas frías de altas latitudes y/o altitud, responden como indicadores de temperatura. En consecuencia una mayor representación relativa de fitolitos chloridoides indica una mayor aridez. Una mayor representación de fitolitos pooides señala una menor temperatura. A partir de testigos lagunares, con ambos indicadores se reconocieron tres períodos climáticos para el lapso 7,0-0,5 ka 14C AP. Por último se señalan interpretaciones que han relacionado estos períodos con cambios culturales, al igual que otras correlaciones que pueden ser relevantes al momento de interpretar o explicar la dinámica paleocultural regional.

Más de lo que se observa con una simple mirada: Mamíferos de los alrededores de Bahía Blanca Luengos Vidal, Estela Maris; Baglioni, Joaquín Los mamíferos, caracterizados fundamentalmente por la presencia de pelos y mamas, representan aquellos animales con que estamos mas familiarizados por ser nuestros compañeros diarios o por representar un recurso económico, mas aún en nuestra región agroganadera.

La bioinformática estructural o la realidad virtual de los medicamentos; Structural bioinformatics: the drugs virtual reality game Marti, Marcelo Adrian; Turjanski, Adrian La bioinformática estructural consiste, entre otras cosas, en realizar una simulación de del comportamiento de biomoléculas, principalmente proteínas y sus entornos, en diferentes situaciones. Al igual que un simulador de vuelo nos puede decir si un piloto se encuentra en condiciones de conducir con éxito un avión a su destino, la simulación con las biomoléculas puede establecer la capacidad de una droga para inhibir algunas enzimas o la posibilidad que dos proteínas puedan interactuar entre ellas. De este modo la bio informática contribuirá a un cambio en el paradigma del diseño de drogas permitiendo una mayor rapidez en su descubrimiento y en el proceso de optimización. Hay ejemplos exitosos de este nuevo paradigma como el caso de los inhibidores selectivos COX-2 como el Celecoxib usados en enfermedades inflamatorias crónicas, los inhibidores de la enzima convertidora de angiotensina (ECA) como el Captopril, empleados en el tratamiento de la hipertensión y diversos compuestos para el tratamiento del HIV.Palabras claves: bioinformática estructural – nuevo paradigma de desarrollo de medicamentos – diseño racional de fármacos – desarrollo de fármacos in silico.; Structural Bioinformatics consist in simulating biomolecules, mainly proteins and their environment in different situations. And just like a flight simulator can tell us, if a pilot is able to bring the plane safely to destiny, biomolecular simulations can determine the ability of a drug to inhibit certain enzyme, or the possibility of two proteins to interact with each other. In this way structural bioinformatics contributed to a change in the drug development paradigm allowing a faster drug discovery and optimization process. Successful examples of the new paradigm are COX-2 selective inhibitors used in chronic inflammations, ACE inhibitor captopril and several compounds to treat HIV among others.

Mirando el mar desde las orillas de un libro : Dos ficciones de Margo Glantz Perilli, Carmen Noemi Margo Glantz  propone una literatura que funciona como búsqueda de sí misma. El movimiento de la prosa se afirma sobre  el pliegue  entre escritura y lectura. Este trabajo recorre dos de sus  primeras ficciones: Doscientas ballenas azules (1979) y  Síndrome de naufragios (1984) que pueden adscribirse a la corriente literaria mexicana que  Glantz llamó la Literatura de la Escritura  en oposición a la Literatura de la Onda.    Sus imágenes subrayan la íntima relación de la escritura con la violencia: el naufragio y la caza de la ballena. Construidos con   fragmentos amplían el objeto hasta transformarlo en constelación simbólica. El lenguaje  se carga del erotismo que exige la reposición de la totalidad y la insistencia del cuerpo.; Margo Glantz proposes a literature that functions in a self-searching manner. The prose moves along the fold between writing and reading. The present article explores two of her early fictions, Doscientas ballenas azules (1979) and Síndrome de naufragios (1984), which can be ascribed to the mexican literary current Glantz named Literatura de la Escritura in opposition to Literatura de la Onda . Its images outline the intimate relation between writing and violence: shipwrecks and the hunting of whale. Building on fragments they amplify the object into a symbolic constellation. Language is full of the eroticism demanded by totality and insistence of the body.

Introduction of the American Bullfrog Lithobates catesbeianus (Anura: Ranidae) in Natural and Modified Environments: An Increasing Conservation Problem in Argentina Barrasso, Diego Andrés; Cajade, Rodrigo; Nenda, Santiago Javier; Baloriani, Gabriel; Herrera, Raúl Several previous studies have established that the introduction of the American bullfrog, Lithobates catesbeianus, Lithobates catesbeianus, produces negative effects on native communities. Herein, the American bullfrog is reported for the first time in the province of Buenos Aires, Argentina in the locality of 9 de Julio. The stomach contents of the collected specimens were examined and the reproduction of the species was also confirmed at the study area. A total of 85.7% (n = 30) of the analyzed stomachs contained prey items, and eleven of these were identified. The prey items belonged mostly to coleopterans (50%) and vertebrates (11%). The pathogen Batrachochytrium dendrobatidis was not found on skin samples examined. The installation of Lithobates catesbeianusn = 30) of the analyzed stomachs contained prey items, and eleven of these were identified. The prey items belonged mostly to coleopterans (50%) and vertebrates (11%). The pathogen Batrachochytrium dendrobatidis was not found on skin samples examined. The installation of Lithobates catesbeianusBatrachochytrium dendrobatidis was not found on skin samples examined. The installation of Lithobates catesbeianus breeding facilities contributes to the incidental release of this species. A tightening of rules in the regulation of aquaculture activities and the use of control programs for naturalized populations are necessary to address the increasing dispersion of the species in Argentina and potential ecological problems.

Bone marrow stromal cells attenuate injury-induced changes in galanin, NPY and NPY Y1 receptor expression after a sciatic nerve constriction Coronel, Maria Florencia; Musolino, P. L.; Brumovsky, Pablo Rodolfo; Hökfelt, T.; Villar, M. J. Single ligature nerve constriction (SLNC) of the rat sciatic nerve triggers neuropathic pain-related behaviors and induces changes in neuropeptide expression in primary afferent neurons. Bone marrow stromal cells (MSCs) injected into the lumbar 4 (L4) dorsal root ganglia (DRGs) of animals subjected to a sciatic nerve SLNC selectively migrate to the other ipsilateral lumbar DRGs (L3, L5 and L6) and prevent mechanical and thermal allodynia. In this study, we have evaluated the effect of MSC administration on the expression of the neuropeptides galanin and NPY, as well as the NPY Y(1)-receptor (Y(1)R) in DRG neurons. Animals were subjected to a sciatic nerve SLNC either alone or followed by the administration of MSCs, phosphate-buffered saline (PBS) or bone marrow non-adherent mononuclear cells (BNMCs), directly into the ipsilateral L4 DRG. Seven days after injury, the ipsilateral and contralateral L4-5 DRGs were dissected out and processed for standard immunohistochemistry, using specific antibodies. As previously reported, SLNC induced an ipsilateral increase in the number of galanin and NPY immunoreactive neurons and a decrease in Y(1)R-positive DRG neurons. The intraganglionic injection of PBS or BNMCs did not modify this pattern of expression. In contrast, MSC administration partially prevented the injury-induced changes in galanin, NPY and Y(1)R expression. The large number of Y(1)R-immunoreactive neurons together with high levels of NPY expression in animals injected with MSCs could explain, at least in part, the analgesic effects exerted by these cells. Our results support MSC participation in the modulation of neuropathic pain and give insight into one of the possible mechanisms involved.

Observaciones sobre las transferencias léxicas del inglés en español bonaerense Hipperdinger, Yolanda Haydee En español bonaerense, numerosos préstamos de lenguas europeas se han incorporado al acervo léxico en los dos últimos siglos, como concomitantes lingüísticos de diversos fenómenos culturales. La última lengua con un rol donante de relevancia es el inglés, como en el caso de muchas otras variedades lingüísticas en el mundo. En este artículo analizamos algunos de los emergentes del influjo del inglés en español bonaerense, particularmente a nivel léxico. En primer lugar, sobre la base de nuestros registros nos ocupamos de revisar algunas correlaciones que comúnmente se dan por supuestas (entre la extensión de uso y la adaptación a la lengua recipiente, entre los usos orales y escritos de los mismos lexemas de préstamo, entre la permanencia en uso de un préstamo y la fijación del modo en que se lo realiza oralmente y/o se lo representa grafémicamente, entre la fijación y la adaptación). Seguidamente nos ocupamos de analizar instancias de hipercorrección, que transparentan la íntima relación entre los usos y las actitudes, tanto como el papel rector que sobre estas últimas ejerce el prestigio de la lengua donante (aun cuando se combine con un conocimiento insuficiente de la misma). Por último, dejamos constancia de usos en los que se verifica una especial posición modélica del inglés, ya que también a sus pautas (además de a las españolas nativas) recurren en ocasiones los hablantes de la región, tanto para la realización de incorporaciones de otras lenguas cuanto para algunas innovaciones creativas.; In the Spanish variety spoken in Buenos Aires, many loanwords from European languages have been incorporated to its lexical store in the last two centuries, as linguistic consequences of different cultural phenomena. The last language with a donor role of significance is English, as in case of lots of other linguistic varieties all over the world. In this article we analyze some of the resultants of the influence of English on Buenos Aires’ Spanish, particularly at the lexical level. Firstly, on the basis of our registers we revise some correlations that are commonly taken for granted (between use extension and adaptation to the recipient language, between oral and written uses from the same borrowed lexemes, between the permanence in use of a loanword and the fixation with which it is orally realized and/or it is graphemically represented, between fixation and adaptation). Secondly, we analyze hypercorrection requests, that clearly show the intimate relationship between uses and attitudes, as well as the guiding role that the prestige of the donor language exerts over the latter (even when it is combined with an insufficient knowledge of it). Lastly, we lend evidence of uses in which a special model position of English is verified, because sometimes regional speakers also fall back on its patterns (as well as on their native Spanish ones) for the realization of other languages’ incorporations or for some creative innovations.

Few-electron semiconductor quantum dots with Gaussian confinement Gomez, Sergio Santiago; Romero, Rodolfo Horacio We have performed Hartree-Fock calculations of the electronic structure of N ≤ 10 electrons in a quantum dot modeled with a confining Gaussian potential well. We discuss the conditions for the stability of N bound electrons in the system. We show that the most relevant parameter determining the number of bound electrons is V 0 R 2. Such a feature arises from widely valid scaling properties of the confining potential. Gaussian Quantum dots having N = 2, 5, and 8 electrons are particularly stable in agreement with the Hund rule. The shell structure becomes less and less noticeable as the well radius increases.

Trypanosoma cruzi: adaptation to its vectors and its hosts Noireau, François; Diosque, Patricio; Jansen, Ana María American trypanosomiasis is a parasitic zoonosis that occurs throughout Latin America. The etiological agent, Trypanosoma cruzi, is able to infect almost all tissues of its mammalian hosts and spreads in the environment in multifarious transmission cycles that may or not be connected. This biological plasticity, which is probably the result of the considerable heterogeneity of the taxon, exemplifies a successful adaptation of a parasite resulting in distinct outcomes of infection and a complex epidemiological pattern. In the 1990s, most endemic countries strengthened national control programs to interrupt the transmission of this parasite to humans. However, many obstacles remain to the effective control of the disease. Current knowledge of the different components involved in elaborate system that is American trypanosomiasis (the protozoan parasite T. cruzi, vectors Triatominae and the many reservoirs of infection), as well as the interactions existing within the system, is still incomplete. The Triatominae probably evolve from predatory reduvids in response to the availability of vertebrate food source. However, the basic mechanisms of adaptation of some of them to artificial ecotopes remain poorly understood. Nevertheless, these adaptations seem to be associated with a behavioral plasticity, a reduction in the genetic repertoire and increasing developmental instability.

Acción, conocimiento y dolo eventual Manrique, Maria Laura En este trabajo señalo algunos desafíos que genera el dolo eventual a una explicación humeana de la acción. Estos desafíos son de dos clases: problemas internos y problemas externos. En cuanto a los problemas internos de la teoría del dolo eventual muestro que una teoría reduccionista o epistémica del dolo se compromete con dar una respuesta negativa a la pregunta sobre la diferencia entre dolo eventual y culpa consciente. Si por el contrario, se acepta un enfoque no reduccionista, no se puede dar cuenta de que el dolo eventual es genuinamente dolo sin alterar los términos de su propia teoría. Este esfuerzo presiona para modificar la teoría en una versión normativizada del dolo. La consecuencia de ello es la separación del dolo con los estados mentales que efectivamente posee el agente, borrando así la diferencia entre responsabilidad por las acciones y responsabilidad por las consecuencias. En cuanto a los inconvenientes de adecuación externa sostendré que la figura del dolo eventual invierte la prioridad conceptual de la explicación sobre la evaluación de las acciones responsabilizando a los agentes por las consecuencias que ocasionaron y no por lo que hicieron.; In this paper the author points out some problems that stem from the connection between contemporary theories in criminal law about dolus eventualis, and our paradigmatic conception of action, i.e. the so called Humean theory. These problems are of two classes: internal and external ones. On the one hand, the author shows that reductionist theories are not able to provide a sound criterion for distinguishing between dolus eventualis and conscious negligence. If reductionist theories are rejected, dolus eventualis can not be regarded as a genuine form of dolus. In order to overcome this problem, criminalists often replace a descriptive point of view on the actual motivation of agents for an adscriptive (normative) conception of dolus, but this shift separates dolus from agents' mental states that determine their actions. As a consequence of this conceptual movement, differences between subjective and objective responsibility actually vanish. On the other hand, the author shows that contemporary theories challenge the conceptual priority of the explanation of actions over their evaluation. Thus, these theories make agents responsible on account of the consequences of their actions rather than by their actions.

Acceleration of Monte Carlo modeling of light transport in turbid media; an approach based on hybrid, theoretical and numerical, calculations Di Rocco, Hector Omar; Iriarte, Daniela Ines; Pomarico, Juan Antonio; Ranea Sandoval, Hector Francisco A novel method to accelerate Monte Carlo (MC) simulations of photon migration in turbid media is presented. It is specifically suited for transillumination studies in slab geometries including some deep inhomogeneity. Propagation up to the inhomogeneity, at a given depth S1, is replaced by theoretical calculations using well established models. Then, photon propagation is continued inside the complete slab using MC rules until detection or absorption occurs. We report improvements in speed in factors up to approximately 10; the deeper the inhomogeneity, the larger the improvement. Examples are given showing that information remains unchanged with respect to pure MC simulations.

Evaluation of chlorine, benzalkonium chloride and lactic acid as sanitizers for reducing Escherichia coli O157:H7 and Yersinia enterocolitica on fresh vegetables Velázquez, Lidia del Carmen; Barbini, Norma Beatriz; Escudero, María Esther; Lucero Estrada, Cecilia Stella Marys; Stefanini de Guzman, Ana Maria Teresa Valentina The effectiveness in the assurance of fresh vegetable microbiological quality of wash solutions containing 200 ppm free chlorine, 0.1 mg/ml benzalkonium chloride, 0.2% and 1% lactic acid was assessed on Escherichia coli O157:H7 and Yersinia enterocolitica contaminated lettuce and tomatoes. Y. enterocolitica reduction on tomatoes (5.08, 4.77 and 4.21 log after 0.2% lactic acid, 200 ppm chlorine and 0.1 mg/ml benzalkonium chloride treatments, respectively) were significantly higher than those for Y. enterocolitica on lettuce and E. coli O157:H7 on both vegetables. Antimicrobial treatment effects on bacterial counts and product quality after subsequent 7 day storage (4 C and 22 C) were determined. No pathogens were found in natural microflora of fresh vegetables.

Caracterización de productos co-cristalizados de sacarosa mediante Rayos X y DSC Deladino, Lorena; Navarro, Alba Sofia del Rosario; Martino, Miriam Nora The objective of the work was to characterize through X-rays, differential scanning calorimetry (DSC) and scanning electron microscopy (SEM), co-crystallized products within a sucrose matrix. These products contained mineral salts, ca1ciumlactate, magnesium suIphate and a lyophilized yerba mate extract (Ilex paraguariensis). The studied techniques allowed comparing the structure ofthe different products and the hydration state of the salts after the process. The co-crystallized products showed the basic crystalline structure of control sample of sucrose. In the case of the minerals, dehydration was not totally accomplished since different salt hydrate structures were detected.

Synthesis and anticonvulsant activity of amino acid-derived sulfamides Gavernet, Luciana; Elvira, Juan E.; Samaja, Gisela Anabel; Pastore, Valentina; Cravero, Mariana Sella; Enrique, Andrea Verónica; Estiu, Guillermina Lucia; Bruno Blanch, Luis Enrique Sulfamides are promising functions for the design of new antiepileptic drugs (Bioorg. Med. Chem. 2007, 15, 1556-1567; 5604-5614). Following previous research in this line, a set of amino acid-derived sulfamides has been designed, synthesized, and tested as new anticonvulsant compounds. The experimental data confirmed the ability of some of the structures to suppress the convulsions originated by the electrical seizure (MES test) at low doses (100 mg/kg).

'Durable Residues': Addressing the use of microwear, a case study from March Hill Briz Godino, Ivan; Alvarez, Myrian Rosa; Spikins, Penny; Needham. Andrew Different cultural and research traditions have led to distinctively different approaches tolithics analysis. An integration of different approaches can often give new ´ways ofseeing´ artefact assemblages and distribution patterns and provide valuable insights intopast activities. Here we present the preliminary results of a project integrating detailedanalytical techniques, focused on processes of production and consumption and socialdynamics in ethnarchaeological contexts in Tierra del Fuego with existing detailed lithicanalysis at Mesolithic sites in the Central Pennines. Such methods, taken fromArgentina (Álvarez) and Spain (Briz), that were developed in ethnoarchaeologicalcontexts employed detailed edge morphological analysis and use wear. When appliedto site A at March Hill, these techniques yielded interesting new insights about activitiesat the site, and provided a test case for such techniques.

Rotigotine transdermal delivery for the treatment of Parkinson's disease Rascol, Olivier; Perez Lloret, Santiago Background: Rotigotine is a non-ergot dopamine agonist that has been developed as a new transdermal formulation, and is indicated for use in early (USA and Europe) and advanced (Europe only) Parkinson's disease (PD). The potential advantages of the rotigotine patch include immediacy of effect onset as intestinal absorption in unneeded, constant drug delivery, and ease of use via application of a once-daily adhesive patch. An interesting element of this profile is constant drug delivery, which may avoid pulsatile dopaminergic stimulation, which has been postulated to be related to the development of motor complications. Objective: To consider the evidence surrounding the profile of rotigotine and, in particular, whether its constant delivery system offers significant benefits to the treatment of early and advanced PD. Methods: Source material was identified using a PubMed search for the term 'rotigotine' (up to March 2008). The review focuses only on publications related to the rotigotine indication for PD. Results/conclusion: The rotigotine transdermal patch demonstrates clinical efficacy, alongside a tolerability profile that appears to be well within the range of that observed with other non-ergot dopamine agonists. The once-daily patch formulation may favour compliance but, in similarity with the other theoretical advantages of constant drug delivery (for example reduced emergence of motor complications, improved tolerance to peripheral AEs), requires further detailed study.

Aminoguanidine impedes human pancreatic tumor growth and metastasis development in nude mice Mohamad, Nora Alicia; Criocco, Graciela P.; Sambuco, Lorena Andrea; Croci, Máximo; Medina, Vanina Araceli; Gutiérrez, Alicia Susana; Bergoc, Rosa Maria; Rivera, Elena Susana; Martín, Gabriela A. Aim: To study the action of aminoguanidine on pancreatic cancer xenografts in relation to cell proliferation, apoptosis, redox status and vascularization. Methods: Xenografts of PANC-1 cells were developed in nude mice. The animals were separated into two groups: control and aminoguanidine treated. Tumor growth, survival and appearance of metastases were determined in vivo in both groups. Tumors were excised and ex vivo histochemical studies were performed. Cell growth was assessed by Ki-67 expression. Apoptosis was studied by intratumoral expression of B cell lymphoma-2 protein (Bcl-2) family proteins and Terminal deoxynucleotidyl transferase biotin-dUTP Nick End Labeling (Tunel). Redox status was evaluated by the expression of endothelial nitric oxide synthase (eNOS), catalase, copper-zinc superoxide dismutase (CuZnSOD), manganese superoxide dismutase (MnSOD) and glutathione peroxidase (GPx). Finally, vascularization was determined by Massons trichromic staining, and by VEGF and CD34 expression. Results: Tumor volumes after 32 d of treatment by aminoguanidine (AG) were significantly lower than in control mice (P < 0.01). Median survival of AG mice was significantly greater than control animals (P < 0.01). The appearance of both homolateral and contralateral palpable metastases was significantly delayed in AG group. Apoptotic cells, intratumoral vascularization (trichromic stain) and the expression of Ki-67, Bax, eNOS, CD34, VEGF, catalase, CuZnSOD and MnSOD were diminished in AG treated mice (P < 0.01), while the expression of Bcl-2 and GPx did not change. Conclusion: The antitumoral action of aminoguanidine is associated with decreased cell proliferation, reduced angiogenesis, and reduced expression of antioxidant enzymes.

Biología reproductiva de la serpiente semiacuática Liophis semiaureus (Serpentes, Colubridae) en el nordeste de Argentina Lopez, Maria Soledad; Giraudo, Alejandro Raul; Arzamendia, Vanesa; Chiaraviglio, Margarita Las serpientes tienen una notable flexibilidad y diversidad en sus tácticas reproductivas, a pesar de ello, los estudios acerca de la biología reproductiva de especies sudamericanas en zonas subtropicales-templadas son escasos. Se analizó la biología reproductiva de Liophis semiaureus en el nordeste de Argentina, incluyendo la madurez y dimorfismo sexual, fecundidad y ciclo reproductivo. Las hembras maduras fueron significativamente más largas, presentaron mayor peso corporal y alcanzaron la madurez sexual a una longitud mayor que los machos. Los machos tuvieron colas más largas que las hembras. El ciclo reproductivo fue estacional con mayor actividad en los períodos templados del año aunque previos a la época de inundaciones. Liophis semiaureus invirtió más energía en la reproducción que en el crecimiento, lo que posibilita que comiencen a reproducirse con tamaños más pequeños con respecto a otras poblaciones, sin retrasar su reproducción hasta alcanzar mayores tamaños. Esta puede ser una estrategia ventajosa en climas estacionales. Las características reproductivas y de dimorfismo sexual en L. semiaureus se encontrarían influenciadas por aspectos filogenéticos, geográficos y ecológicos, lo que determina que la especie responda de manera general al patrón reproductivo del grupo taxonómico pero con particularidades propias determinadas por los factores geográficos y los requerimientos ecológicos.

Diversification of inflorescence development in The PCK clade (Poaceae: Panicoideae: Paniceae) Reinheimer, Renata; Zuloaga, Fernando Omar; Vegetti, Abelardo Carlos; Pozner, Raúl Ernesto In grasses, inflorescence diversification and its correlation with species evolution are intriguing and not well understood. Part of this problem lies in our lack of comprehension about the inflorescence morphological complexity of grasses. We focused our study on the PCK clade (named for phosphoenol pyruvate carboxykinase), a well‐supported monophyletic group for which the relationships among its taxa are not well resolved. Interestingly, the PCK clade has an extensive diversity of adult inflorescence forms. A comparative developmental approach can help us to understand the basis of such morphological differences as well as provide characters that can be used in phylogenetic studies of the group. Using SEM studies, we demonstrate that inflorescence morphology in this clade is even more complex than what is typically observed in adult forms. We describe a number of new characters, and some classical features previously used for taxonomic purposes are redefined on the basis of development. We also define four morphological groups combining adult inflorescence form and development, and we discuss some of the evolutionary aspects of inflorescence diversification in the PCK clade. Taxonomic delimitation among genera in the PCK clade remains confusing and unclear where molecular and morphological studies support different classifications.