Mauricio Bahena García - Academia.edu (original) (raw)
Papers by Mauricio Bahena García
Zootaxa
Suphisellus shorti sp. n. is described from "Los Llanos", Venezuela, which brings to six the numb... more Suphisellus shorti sp. n. is described from "Los Llanos", Venezuela, which brings to six the number of species included in the Noteridae genus Suphisellus Crotch, 1873 recorded in this country. Specimens were collected in The Plains region in Venezuela (Apure and Guarico states) using either a light trap or a net. Description and illustration of the new species are provided along with a discussion of its systematic position. The new species can be distinguished from the other species of the genus by the following main characters: crease at posterolateral angle of pronotum weakly marked; numerous setae covering entire surface of prosternal process and medial part of prosternum; shape of male genitalia.
Two new genera and species are described. Spanglerodessus n. gen. is described to include the sin... more Two new genera and species are described. Spanglerodessus n. gen. is described to include the single new species, S. shor-ti n. sp. from localities in eastern Venezuela and western Guyana. This genus is similar to Bidessodes Régimbart and Fon-tidessus Miller and Spangler, but differs from the first in having overall dark coloration, lack of dorsal color patterns or iridescence, a broad lateral bead, and broad and robust habitus. From Fontidessus the genus differs in being much more robust and lacking natatory setae. Incomptodessus n. gen. is described to include a single new species I. camachoi n. sp. from localities in the upper Orinoco River basin in Amazonas and Bolivar States. This genus differs from similar bidessine genera, Sharphydrus Omer-Cooper, Tyndallhydrus Sharp, Liodessus Guignot and Neobidessus Young, in having impunc-tate metacoxae and metaventrite and lacking basal striae on the elytra. Resumen Dos nuevos géneros y especies se describen. Spanglerodessus n. gen. se de...
Systematic Entomology
Are noterids specialised meruids (Coleoptera, Adephaga)? A reply to Dressler et al. Recently, we ... more Are noterids specialised meruids (Coleoptera, Adephaga)? A reply to Dressler et al. Recently, we described the first known larvae of the enigmatic aquatic beetle family Meruidae (Alarie et al., 2011) and coded 28 larval features into a limited character matrix of 12 taxa to provide a phylogenetic context to the morphology that we described and discussed. In our analysis, Meru was placed as sister to the remaining Dytiscoidea – an identical placement to a preceding morphological analysis by Dressler & Beutel (2010). Subsequently, incorporating the newly illuminated Meru larval characters, Dressler et al. (2011) provided a re-analysis in the context of an expanded dataset. Based on this new analysis, Dressler et al. (2011), refuted the prior topology and made surprising claims about the morphology and ecology of Meru and Notomicrus. Further, despite basing their analysis and findings on the assumption that Meru adults and larvae were associated properly, they concluded that this assoc...
Systematic Entomology, 2015
The phylogeny of the aquatic beetle family Hydroscaphidae is inferred from one mitochondrial (COI... more The phylogeny of the aquatic beetle family Hydroscaphidae is inferred from one mitochondrial (COI) and five nuclear (18S, 28S, wingless, arginine kinase and CAD) genes. Bayesian, maximum likelihood and maximum parsimony analyses were conducted on a combined dataset that included representatives from all three described hydroscaphid genera, three new species of the family of uncertain placement, and representatives from the myxophagan families Sphaeriusidae, Torridincolidae and Lepiceridae. All analyses strongly supported a set of nearly identical trees in which (i) the monophyly of Hydroscaphidae and all its constituent genera is affirmed, (ii) the nearly cosmopolitan genus Hydroscapha is sister to the remaining and exclusively Neotropical genera, and (iii) the new, morphologically aberrant taxa from the Guiana Shield form a monophylum separate from any described genus. Here, we review each genus of the family including the description of Confossa Short, Joly, García & Maddison gen.n. to accommodate three new species: C. sculptura sp.n., C. falcata sp.n. and C. minima sp.n. The new genus possesses a remarkable perforated abdominal surface that we hypothesize serves as a respiratory plastron. We also present a key to the genera and a catalogue of species of the family. 214
Zootaxa, 2014
Radicitus gen. n. is described to accommodate three new species of water scavenger beetles from t... more Radicitus gen. n. is described to accommodate three new species of water scavenger beetles from the Guiana Shield region of South America: R. ayacucho sp. n. (Venezuela), R. granitum sp. n. (Venezuela), and R. surinamensis sp. n. (Suriname). The genus is placed in the subfamily Acidocerinae, and likely shares an affinity with the genus Helochares Mulsant and its relatives. It is characterized by its convex body form, short maxillary palps, partially glabrous hind femora, and complete fifth abdominal ventrite. All collections of the new genus were made from root mats and debris from seepages over rock outcrops or, rarely, root mats from streams. Individual females of all three species were observed to adhere their egg case to the venter of the abdomen.
Zootaxa, 2013
Three new species of Oocyclus Sharp, 1882 are described from tropical South America: O. maluz sp.... more Three new species of Oocyclus Sharp, 1882 are described from tropical South America: O. maluz sp. n. (Venezuela), O. miza sp. n. (Venezuela), and O. brunneus sp. n.
Fusion Science and Technology
Linear IFMIF Prototype Accelerator (LIPAC) is the prototype accelerator of the Engineering Valida... more Linear IFMIF Prototype Accelerator (LIPAC) is the prototype accelerator of the Engineering Validation and Engineering Design Activities (EVEDA) phase of the International Fusion Materials Irradiation Facility (IFMIF) project. The EVEDA phase is a first IFMIF step devoted to the construction of prototypes of the main units. The deuteron beam of LIPAC (125 mA, 9 MeV) is stopped by a conical copper beam stop, giving rise to neutron and photon sources that must be shielded to comply with dose requirements. A reliable characterization of these secondary sources is a mandatory task. The built-in-semi-analytical nuclear models used by advanced Monte Carlo transport codes as Monte Carlo N-Particle extended (MCNPX) or Particle and Heavy Ion Transport code System (PHITS) have been demonstrated as unreliable for describing deuteron interactions and secondary particle production at these low energies. The use of reliable external nuclear data is consequently necessary in the design of the LlPAC...
Systematic Entomology, 2012
Cortex, 2003
In addition to their deficit in overt face recognition, patients with prosopagnosia also have dif... more In addition to their deficit in overt face recognition, patients with prosopagnosia also have difficulties in matching sequentially presented unfamiliar faces. Here we assessed the possibility that covert matching of faces was present in a case with prosopagnosia using event-related potentials (ERPs). The participants (patient FE and normal controls) were challenged with a face-identity matching task, in which they decided whether two sequentially presented photographs of unfamiliar faces represented the same person. Only internal face features were used and the two faces in a pair differed in emotional expression. FE failed to overtly match these stimuli. In contrast, the ERPs revealed evidence of covert matching. If the two faces within a pair of stimuli depicted different posers, then the response to the second face contained an enhanced N300 compared to the situation where the identity of the faces was the same. The latency of the N300 was the same as a similar component found in controls. These results suggest that some cases with prosopagnosia have a covert ability to match unfamiliar faces, with similar temporal dynamics as controls, which in contrast with the idea that a generalized slowing of face processing occurs in all cases of prosopagnosia.
SPIRAL2 facility will produce 5mA of deuterons at 40 MeV. A beam dump device has been designed to... more SPIRAL2 facility will produce 5mA of deuterons at 40 MeV. A beam dump device has been designed to stop the beam. The residual dose rates in the beam dump room during beam-off phases at cooling times up to one year have been computed using the following methodology: i) ISABEL built-in MCNPX nuclear model to deal with deuterons transport and production and transport of secondary neutrons, ii) deuteron and neutron induced activation were simulated using ACAB code and EAF2007 library, iii) decay gammas were transported using MCNPX to compute residual dose rate. The ambient dose equivalent rate is mainly due to the activated copper pieces of the beam stop. Uncertainties in the results are mainly due to d-Cu activation cross sections and due to the determination of the neutron source. Correction factors to improve the activation cross section are proposed and residual dose rate range depending nuclear data used to compute the neutron source (nuclear model or library) will be evaluated.
Anti-Cancer Drugs, 2008
Mantle cell lymphoma (MCL) is a B-cell lymphoid tumor that expresses CD20 and is associated with ... more Mantle cell lymphoma (MCL) is a B-cell lymphoid tumor that expresses CD20 and is associated with a poor prognosis. Central nervous system involvement has been associated with particularly dismal outcome. We report a 62-year-old male with MCL and meningeal lymphomatosis. The patient was treated with intrathecal rituximab (IT-R) 25 mg every third day for five doses with clearance of tumor after the third dose. Systemic therapy consisted of R-HyperCVAD alternating with rituximab, high-dose methotrexate, and cytarabine every 21 days, with IT-R on day 1 of each chemotherapy cycle. The patient was consolidated with an autologous stem cell transplant and remains in remission 23 months later.
This paper describes the local shielding design process of the IFMIF/EVEDA Beam Dump and the most... more This paper describes the local shielding design process of the IFMIF/EVEDA Beam Dump and the most relevant results obtained from the simulations. Different geometries and materials have been considered, and the design has been optimized taking into account the origin of the doses, the effect of the walls of the accelerator vault and the space restrictions. The initial idea was to shield the beam stopper with a large water tank of easy transport and dismantling but it was shown to be insufficient to satisfy the dose limit requirements, basically due to photon dose, and hence a denser shield combining hydrogenous and heavy materials was preferred. It will be shown that, with this new shielding, dose rate outside the accelerator vault during operation comply with the legal limits and unrestricted maintenance operations inside most of the vault are possible after a reasonable cooling time after shutdown.
Annals of the Entomological Society of America, 2011
Meruidae, or comb-clawed cascade beetles, are a recently discovered monotypic family of Adephaga ... more Meruidae, or comb-clawed cascade beetles, are a recently discovered monotypic family of Adephaga endemic to Venezuela. The larvae of Meruidae are described for the Þrst time, based on material of Meru phyllisae , collected together with adults in southern Venezuela. External morphological features, including chaetotaxy, are reported for the mature larva and an assessment made of the polarity of larval characters of phylogenetic utility in Adephaga. Larvae of Meruidae possess a mixture of primitive and derived character states, and they are unique within the Adephaga in that here the mandibles are asymmetrical, the respiratory system is comprised of only two pairs of spiracles (ϭoligopneustic), the claws are pectinate, and the abdominal sternite VIII is prolonged overlapping the abdominal sternite IX. A parsimony analysis based on 18 informative larval characteristics was conducted with the program PAUP*. The most parsimonious trees conÞrm Meruidae as a relatively basal lineage within the Dytiscoidea. Both Meru Spangler & Steiner and Noteridae are hypothesized to have diverged anterior to Amphizoidae, Aspidytidae, Hygrobiidae, and Dytiscidae.
Fusion Science and Technology
A preliminary beam dump cartridge design has been proposed recently for the IFMIF-EVEDA accelerat... more A preliminary beam dump cartridge design has been proposed recently for the IFMIF-EVEDA accelerator. Copper was the material chosen for the beam stop. In this paper we investigate the possibility of designing a practical shielding for the proposed cartridge so that it can offer an acceptable radioprotection response during both beam-on and beam-off phases. The radioprotection analysis is performed for the whole beam dump component located inside the already designed accelerator vault. A comprehensive methodology has been proposed to deal with the problem. Special attention has been paid to the treatment of the neutron source and a significant effort has been devoted to validation purposes. It is justified that prompt and residual dose rates can be provided with a reasonably conservative margin. A base line shielding consisting of a 1 m water tank and a concrete shield of 1 m thickness in front of the tank can be a good approach to fulfil the radioprotection requirement assigned to t...
Zootaxa
Suphisellus shorti sp. n. is described from "Los Llanos", Venezuela, which brings to six the numb... more Suphisellus shorti sp. n. is described from "Los Llanos", Venezuela, which brings to six the number of species included in the Noteridae genus Suphisellus Crotch, 1873 recorded in this country. Specimens were collected in The Plains region in Venezuela (Apure and Guarico states) using either a light trap or a net. Description and illustration of the new species are provided along with a discussion of its systematic position. The new species can be distinguished from the other species of the genus by the following main characters: crease at posterolateral angle of pronotum weakly marked; numerous setae covering entire surface of prosternal process and medial part of prosternum; shape of male genitalia.
Two new genera and species are described. Spanglerodessus n. gen. is described to include the sin... more Two new genera and species are described. Spanglerodessus n. gen. is described to include the single new species, S. shor-ti n. sp. from localities in eastern Venezuela and western Guyana. This genus is similar to Bidessodes Régimbart and Fon-tidessus Miller and Spangler, but differs from the first in having overall dark coloration, lack of dorsal color patterns or iridescence, a broad lateral bead, and broad and robust habitus. From Fontidessus the genus differs in being much more robust and lacking natatory setae. Incomptodessus n. gen. is described to include a single new species I. camachoi n. sp. from localities in the upper Orinoco River basin in Amazonas and Bolivar States. This genus differs from similar bidessine genera, Sharphydrus Omer-Cooper, Tyndallhydrus Sharp, Liodessus Guignot and Neobidessus Young, in having impunc-tate metacoxae and metaventrite and lacking basal striae on the elytra. Resumen Dos nuevos géneros y especies se describen. Spanglerodessus n. gen. se de...
Systematic Entomology
Are noterids specialised meruids (Coleoptera, Adephaga)? A reply to Dressler et al. Recently, we ... more Are noterids specialised meruids (Coleoptera, Adephaga)? A reply to Dressler et al. Recently, we described the first known larvae of the enigmatic aquatic beetle family Meruidae (Alarie et al., 2011) and coded 28 larval features into a limited character matrix of 12 taxa to provide a phylogenetic context to the morphology that we described and discussed. In our analysis, Meru was placed as sister to the remaining Dytiscoidea – an identical placement to a preceding morphological analysis by Dressler & Beutel (2010). Subsequently, incorporating the newly illuminated Meru larval characters, Dressler et al. (2011) provided a re-analysis in the context of an expanded dataset. Based on this new analysis, Dressler et al. (2011), refuted the prior topology and made surprising claims about the morphology and ecology of Meru and Notomicrus. Further, despite basing their analysis and findings on the assumption that Meru adults and larvae were associated properly, they concluded that this assoc...
Systematic Entomology, 2015
The phylogeny of the aquatic beetle family Hydroscaphidae is inferred from one mitochondrial (COI... more The phylogeny of the aquatic beetle family Hydroscaphidae is inferred from one mitochondrial (COI) and five nuclear (18S, 28S, wingless, arginine kinase and CAD) genes. Bayesian, maximum likelihood and maximum parsimony analyses were conducted on a combined dataset that included representatives from all three described hydroscaphid genera, three new species of the family of uncertain placement, and representatives from the myxophagan families Sphaeriusidae, Torridincolidae and Lepiceridae. All analyses strongly supported a set of nearly identical trees in which (i) the monophyly of Hydroscaphidae and all its constituent genera is affirmed, (ii) the nearly cosmopolitan genus Hydroscapha is sister to the remaining and exclusively Neotropical genera, and (iii) the new, morphologically aberrant taxa from the Guiana Shield form a monophylum separate from any described genus. Here, we review each genus of the family including the description of Confossa Short, Joly, García & Maddison gen.n. to accommodate three new species: C. sculptura sp.n., C. falcata sp.n. and C. minima sp.n. The new genus possesses a remarkable perforated abdominal surface that we hypothesize serves as a respiratory plastron. We also present a key to the genera and a catalogue of species of the family. 214
Zootaxa, 2014
Radicitus gen. n. is described to accommodate three new species of water scavenger beetles from t... more Radicitus gen. n. is described to accommodate three new species of water scavenger beetles from the Guiana Shield region of South America: R. ayacucho sp. n. (Venezuela), R. granitum sp. n. (Venezuela), and R. surinamensis sp. n. (Suriname). The genus is placed in the subfamily Acidocerinae, and likely shares an affinity with the genus Helochares Mulsant and its relatives. It is characterized by its convex body form, short maxillary palps, partially glabrous hind femora, and complete fifth abdominal ventrite. All collections of the new genus were made from root mats and debris from seepages over rock outcrops or, rarely, root mats from streams. Individual females of all three species were observed to adhere their egg case to the venter of the abdomen.
Zootaxa, 2013
Three new species of Oocyclus Sharp, 1882 are described from tropical South America: O. maluz sp.... more Three new species of Oocyclus Sharp, 1882 are described from tropical South America: O. maluz sp. n. (Venezuela), O. miza sp. n. (Venezuela), and O. brunneus sp. n.
Fusion Science and Technology
Linear IFMIF Prototype Accelerator (LIPAC) is the prototype accelerator of the Engineering Valida... more Linear IFMIF Prototype Accelerator (LIPAC) is the prototype accelerator of the Engineering Validation and Engineering Design Activities (EVEDA) phase of the International Fusion Materials Irradiation Facility (IFMIF) project. The EVEDA phase is a first IFMIF step devoted to the construction of prototypes of the main units. The deuteron beam of LIPAC (125 mA, 9 MeV) is stopped by a conical copper beam stop, giving rise to neutron and photon sources that must be shielded to comply with dose requirements. A reliable characterization of these secondary sources is a mandatory task. The built-in-semi-analytical nuclear models used by advanced Monte Carlo transport codes as Monte Carlo N-Particle extended (MCNPX) or Particle and Heavy Ion Transport code System (PHITS) have been demonstrated as unreliable for describing deuteron interactions and secondary particle production at these low energies. The use of reliable external nuclear data is consequently necessary in the design of the LlPAC...
Systematic Entomology, 2012
Cortex, 2003
In addition to their deficit in overt face recognition, patients with prosopagnosia also have dif... more In addition to their deficit in overt face recognition, patients with prosopagnosia also have difficulties in matching sequentially presented unfamiliar faces. Here we assessed the possibility that covert matching of faces was present in a case with prosopagnosia using event-related potentials (ERPs). The participants (patient FE and normal controls) were challenged with a face-identity matching task, in which they decided whether two sequentially presented photographs of unfamiliar faces represented the same person. Only internal face features were used and the two faces in a pair differed in emotional expression. FE failed to overtly match these stimuli. In contrast, the ERPs revealed evidence of covert matching. If the two faces within a pair of stimuli depicted different posers, then the response to the second face contained an enhanced N300 compared to the situation where the identity of the faces was the same. The latency of the N300 was the same as a similar component found in controls. These results suggest that some cases with prosopagnosia have a covert ability to match unfamiliar faces, with similar temporal dynamics as controls, which in contrast with the idea that a generalized slowing of face processing occurs in all cases of prosopagnosia.
SPIRAL2 facility will produce 5mA of deuterons at 40 MeV. A beam dump device has been designed to... more SPIRAL2 facility will produce 5mA of deuterons at 40 MeV. A beam dump device has been designed to stop the beam. The residual dose rates in the beam dump room during beam-off phases at cooling times up to one year have been computed using the following methodology: i) ISABEL built-in MCNPX nuclear model to deal with deuterons transport and production and transport of secondary neutrons, ii) deuteron and neutron induced activation were simulated using ACAB code and EAF2007 library, iii) decay gammas were transported using MCNPX to compute residual dose rate. The ambient dose equivalent rate is mainly due to the activated copper pieces of the beam stop. Uncertainties in the results are mainly due to d-Cu activation cross sections and due to the determination of the neutron source. Correction factors to improve the activation cross section are proposed and residual dose rate range depending nuclear data used to compute the neutron source (nuclear model or library) will be evaluated.
Anti-Cancer Drugs, 2008
Mantle cell lymphoma (MCL) is a B-cell lymphoid tumor that expresses CD20 and is associated with ... more Mantle cell lymphoma (MCL) is a B-cell lymphoid tumor that expresses CD20 and is associated with a poor prognosis. Central nervous system involvement has been associated with particularly dismal outcome. We report a 62-year-old male with MCL and meningeal lymphomatosis. The patient was treated with intrathecal rituximab (IT-R) 25 mg every third day for five doses with clearance of tumor after the third dose. Systemic therapy consisted of R-HyperCVAD alternating with rituximab, high-dose methotrexate, and cytarabine every 21 days, with IT-R on day 1 of each chemotherapy cycle. The patient was consolidated with an autologous stem cell transplant and remains in remission 23 months later.
This paper describes the local shielding design process of the IFMIF/EVEDA Beam Dump and the most... more This paper describes the local shielding design process of the IFMIF/EVEDA Beam Dump and the most relevant results obtained from the simulations. Different geometries and materials have been considered, and the design has been optimized taking into account the origin of the doses, the effect of the walls of the accelerator vault and the space restrictions. The initial idea was to shield the beam stopper with a large water tank of easy transport and dismantling but it was shown to be insufficient to satisfy the dose limit requirements, basically due to photon dose, and hence a denser shield combining hydrogenous and heavy materials was preferred. It will be shown that, with this new shielding, dose rate outside the accelerator vault during operation comply with the legal limits and unrestricted maintenance operations inside most of the vault are possible after a reasonable cooling time after shutdown.
Annals of the Entomological Society of America, 2011
Meruidae, or comb-clawed cascade beetles, are a recently discovered monotypic family of Adephaga ... more Meruidae, or comb-clawed cascade beetles, are a recently discovered monotypic family of Adephaga endemic to Venezuela. The larvae of Meruidae are described for the Þrst time, based on material of Meru phyllisae , collected together with adults in southern Venezuela. External morphological features, including chaetotaxy, are reported for the mature larva and an assessment made of the polarity of larval characters of phylogenetic utility in Adephaga. Larvae of Meruidae possess a mixture of primitive and derived character states, and they are unique within the Adephaga in that here the mandibles are asymmetrical, the respiratory system is comprised of only two pairs of spiracles (ϭoligopneustic), the claws are pectinate, and the abdominal sternite VIII is prolonged overlapping the abdominal sternite IX. A parsimony analysis based on 18 informative larval characteristics was conducted with the program PAUP*. The most parsimonious trees conÞrm Meruidae as a relatively basal lineage within the Dytiscoidea. Both Meru Spangler & Steiner and Noteridae are hypothesized to have diverged anterior to Amphizoidae, Aspidytidae, Hygrobiidae, and Dytiscidae.
Fusion Science and Technology
A preliminary beam dump cartridge design has been proposed recently for the IFMIF-EVEDA accelerat... more A preliminary beam dump cartridge design has been proposed recently for the IFMIF-EVEDA accelerator. Copper was the material chosen for the beam stop. In this paper we investigate the possibility of designing a practical shielding for the proposed cartridge so that it can offer an acceptable radioprotection response during both beam-on and beam-off phases. The radioprotection analysis is performed for the whole beam dump component located inside the already designed accelerator vault. A comprehensive methodology has been proposed to deal with the problem. Special attention has been paid to the treatment of the neutron source and a significant effort has been devoted to validation purposes. It is justified that prompt and residual dose rates can be provided with a reasonably conservative margin. A base line shielding consisting of a 1 m water tank and a concrete shield of 1 m thickness in front of the tank can be a good approach to fulfil the radioprotection requirement assigned to t...
Teorías de la cinética química, 2018
Se describen la teoría de colisiones, mecánica estadística del equilibrio químico, teoría de las ... more Se describen la teoría de colisiones, mecánica estadística del equilibrio químico, teoría de las velocidades absolutas o del estado de transición y teoría total de la cinética química.
Dentro del proceso de fabricación de llantas de caucho, se utilizan diversas maquinarias involucr... more Dentro del proceso de fabricación de llantas de caucho, se utilizan diversas maquinarias involucradas en trabajar el caucho por medio de operaciones unitarias que en conjunto forman el producto deseado, el neumático. Las calandrias juegan un papel importante, ya que forma láminas de caucho uniformes con anchura y grosor definidos.