semestre de 2006. La actividad con los niños inicia con una tabla construida a partir del número ... more semestre de 2006. La actividad con los niños inicia con una tabla construida a partir del número 1, sumando consecutivamente 0, 1, 2, etc., las sumas parciales de esta tabla, nos dan otra tabla cuyos elementos son los números poligonales; fijamos nuestra atención sobre los números triangulares, en particular cuando las sumas de algunos de ellos también es un número triangular.
Background: Gastric cancer (GC) is the fourth most common cause of cancer deaths around the world... more Background: Gastric cancer (GC) is the fourth most common cause of cancer deaths around the world and the first cause of cancer deaths in Peru; however, there are no prospective trials for adjuvant chemotherapy in GC after curative gastrectomy in this country. The objective of this study was to evaluate the effectiveness of adjuvant chemotherapy in stage II-III gastric cancer patients who underwent D2 gastrectomy. Methods: We included patients with stage II-III gastric cancer who underwent radical gastrectomy and D2 dissection between 2014 and 2016 at our institution. Patients received 3-week cycles of capecitabine (1,000 mg/m² twice daily on days 1-14) plus oxaliplatin (130 mg/m² on day 1) for 6 months. Survival curves were estimated with the Kaplan-Meier method, and the Cox proportional hazards model was used to identify prognostic factors for survival. Results: In total, 173 patients were included: 100 (57.8%) patients received adjuvant chemotherapy and surgery (AChS) and 73 (42.2%) surgery alone (SA). Three-year diseasefree survival (DFS) was higher in the AChS groups (69%) than in the SA group (52.6%) (p = 0.034). Regarding overall survival (OS), 31 patients (31%) died in the AChS group compared with 34 (46.6%) in the SA group (p = 0.027). In the multivariate analysis, adjuvant chemotherapy was an independent prognostic factor for DFS (HR = 0.60; 95% CI = 0.37-0.97; p = 0.036) and OS (HR = 0.58; 95% CI = 0.36-0.95; p = 0.029). ACh showed consistent benefit in DFS and OS for patients with albumin >3.5 g/dL, lymphovascular and perineural invasion, pT4, pN2-3, pathologic stage (PS) IIIA and IIIB and lymph node ratio (LNR) > 13.1. Conclusion: These data suggest that adjuvant capecitabine and oxaliplatin reduce the recurrence and mortality in patients with stage II-III gastric cancer who underwent D2 gastrectomy. PS IIIA and IIIB and LNR > 13.1 benefited more from receiving adjuvant chemotherapy and poorly cohesive gastric carcinoma did not significantly reduce the rates of survival.
Revista de gastroenterologia del Peru : organo oficial de la Sociedad de Gastroenterologia del Peru, 2012
Identify prognostic factors associated to total or proximal gastrectomy with or without splenecto... more Identify prognostic factors associated to total or proximal gastrectomy with or without splenectomy and / or distal pancreatectomy in patient with proximal gastric cancer. Evaluate the frequency of lymph node metastasis to the hilum and splenic artery, postoperative morbidity and mortality and the impact of lymphadenectomy of group 10 and 11 on long term survival. We performed an observational, descriptive, longitudinal and retrospective study analyzing patients with diagnostic of proximal third gastric adenocarcinoma subjected to total or proximal gastrectomy with or without splenectomy or distal pancreatectomy in the service of Abdomen of the Instituto Nacional de Enfermedades Neoplásicas between 1990 and 2005. Overall survival for each of the groups was calculated using the Kaplan-Meier method, prognostic factors were evaluated using univariate and multivariate analysis. We studied 219 patients with proximal third gastric adenocarcinoma (cardias and bottom), of wich, according to inclusion criteria, only qualify 129 (N=129): 22 (17.1%) were treated by gastrectomy alone, 79 (61.2%) gastrectomy associated witch splenectomy and 28 (21.7%) gastrectomy with distal pancreatosplenectomy, constituting three treatment groups. We compared the survival of each group and each factor analyzed, determining the following prognostic factors: lymph node metastasis (N2-N3), degree of differentiation, undifferentiated tumors and Borrmann III and IV tumors. Neither splenectomy or distal pancreatectosplenectomy improved survival compared to the gastrectomy alone. The morbidity and mortality was higher in patients with more aggressive but more aggressive surgery without significant value. The number of nodes removed in patients who had pancreatosplenectomy and /or splenectomy was higher, however, had no impact on survival at 5 years.
2016. Bancos naturales de invertebrados bentónicos comerciales y zonas de pesca artesanal. Tumbes... more 2016. Bancos naturales de invertebrados bentónicos comerciales y zonas de pesca artesanal. Tumbes, Perú. Otoño 2014. Inf Inst Mar Perú. 43(3): 275-297.-Se efectuó evaluación biológica y oceanográfica en bancos naturales (intermareales y submareales) del litoral de Tumbes del 24 de mayo al 20 de junio 2014. En el intermareal se evaluaron 31 estaciones, y en el submareal 186 estaciones, mediante buceo semiautónomo; temperatura, pH y oxígeno disuelto (OD) tuvieron valores homogéneos. En el intermareal arenoso se identificaron bancos naturales de palabritas Donax dentifer y D. obesulus; en el rocoso, parches de ostra Crassostrea iridescens y percebe Pollicipes elegans. En el submareal rocoso se registraron bancos naturales de ostra Crassostrea iridescens y pulpo Octopus mimus; en fondos blandos se apreciaron parches de Chione amathusia y Tellina sp.; los moluscos y crustáceos presentaron mayor número de especies. En esta zona, la pendiente del relieve submarino aumentó de norte a sur, p...
En el seminario de algebra de la Universidad Pedagogica Nacional orientado por el grupo de algebr... more En el seminario de algebra de la Universidad Pedagogica Nacional orientado por el grupo de algebra, estamos interesados en estudiar el proceso matematico de Analizar, que involucra descomponer elementos de una estructura en elementos distinguidos de la misma, un ejemplo de esto es la descomposicion en factores primos en el conjunto de los naturales, sin embargo, cuando se indaga sobre la demostracion del teorema fundamental de la aritmetica, por lo general se encuentra que involucra a los enteros, lo que lleva a cuestionar si este se puede demostrarse en los naturales a partir de una de sus axiomaticas; esta pregunta se traslado a los participantes del seminario en el 2013, en esta propuesta se presentan algunos resultados obtenidos.
Se presenta la interpretacion que el grupo de Algebra de la Universidad Pedagogica Nacional tiene... more Se presenta la interpretacion que el grupo de Algebra de la Universidad Pedagogica Nacional tiene del proceso matematico de analizar, caracterizando las dos formas en las que este se utiliza para estudiar una estructura algebraica, a saber el analisis de una estructura y en la estructura, y mostrando ejemplos de anillos en los que el concepto de divisibilidad permite abordar actividades en las que se explicita el proceso de analizar bajo su segunda forma.
Thermography enables non-invasive, accessible, and easily repeated foot temperature measurements ... more Thermography enables non-invasive, accessible, and easily repeated foot temperature measurements for diabetic patients, promoting early detection and regular monitoring protocols, that limit the incidence of disabling conditions associated with diabetic foot disorders. The establishment of this application into standard diabetic care protocols requires to overcome technical issues, particularly the foot sole segmentation. In this work we implemented and evaluated several segmentation approaches which include conventional and Deep Learning methods. Multimodal images, constituted by registered visual-light, infrared and depth images, were acquired for 37 healthy subjects. The segmentation methods explored were based on both visual-light as well as infrared images, and optimization was achieved using the spatial information provided by the depth images. Furthermore, a ground truth was established from the manual segmentation performed by two independent researchers. Overall, the perfor...
Management of constipation associated with advanced cancers, chemotherapy and opioid-induced cons... more Management of constipation associated with advanced cancers, chemotherapy and opioid-induced constipation by oral herbal supplement in heterogeneous group of gastrointestinal, hepatobiliary and pancreatic cancers
Los peces venenosos y tóxicos forman parte de la riqueza en biodiversidad del Perú, sus venenos y... more Los peces venenosos y tóxicos forman parte de la riqueza en biodiversidad del Perú, sus venenos y toxinas contienen metabolitos que pueden emplearse para producir sustancias farmacológicas. La investigación tuvo como objetivo identificar, mediante ADN barcoding, las especies de peces venenosos y tóxicos en el manglar de Tumbes. Se recolectaron 46 ejemplares de estos peces que fueron identificados morfológicamente. Para el análisis de ADN barcoding, se obtuvo sus secuencias de un fragmento del gen de la subunidad I de la citocromo oxidasa (COI), con las cuales se realizó su identificación en Blast y Bold. Se realizó el análisis filogenético mediante Neighbor joining (NJ), automatic barcode gap discovery (ABGD) y modelo generalizado mixto de Yule y coalescencia (GMYC), que confirmaron la asignación de especies. Mediante ADN barcoding se identificó las especies: Daector dowi, Diodon holocanthus, Sphoeroides andersonianus, S. annulatus, S. kendalli, S. sechurae, Gymnura marmorata, Urotrygon asterias y U. peruanus. En algunos ejemplares la identificación mediante ADN barcoding, caracteres morfológicos y análisis filogenético fueron disimiles como en los géneros Sphoeroides y Urotrygon, por lo que deberían realizarse más estudios para confirmar la presencia de complejos de especies altamente emparentadas en ellos.
2016. Bancos naturales de invertebrados bentónicos comerciales y zonas de pesca artesanal. Tumbes... more 2016. Bancos naturales de invertebrados bentónicos comerciales y zonas de pesca artesanal. Tumbes, Perú. Otoño 2014. Inf Inst Mar Perú. 43(3): 275-297.-Se efectuó evaluación biológica y oceanográfica en bancos naturales (intermareales y submareales) del litoral de Tumbes del 24 de mayo al 20 de junio 2014. En el intermareal se evaluaron 31 estaciones, y en el submareal 186 estaciones, mediante buceo semiautónomo; temperatura, pH y oxígeno disuelto (OD) tuvieron valores homogéneos. En el intermareal arenoso se identificaron bancos naturales de palabritas Donax dentifer y D. obesulus; en el rocoso, parches de ostra Crassostrea iridescens y percebe Pollicipes elegans. En el submareal rocoso se registraron bancos naturales de ostra Crassostrea iridescens y pulpo Octopus mimus; en fondos blandos se apreciaron parches de Chione amathusia y Tellina sp.; los moluscos y crustáceos presentaron mayor número de especies. En esta zona, la pendiente del relieve submarino aumentó de norte a sur, p...
Identificación mediante ADN barcode de peces invasores en el manglar de Tumbes (Perú) Identificat... more Identificación mediante ADN barcode de peces invasores en el manglar de Tumbes (Perú) Identification by DNA barcode of invading fish in the mangrove of Tumbes (Peru)
The population of Mobula birostris (“giant manta ray”) found in the waters of northern Peru and E... more The population of Mobula birostris (“giant manta ray”) found in the waters of northern Peru and Ecuador is believed to be the largest in the world (Harding & Beirwagen, 2009). This species is considered to be the largest within the group of manta rays, as they attains at least 670 cm disc width (reported to 910 cm) (White et al., 2006) and there is a record of an individual weighing 2000 kg (Kunjipalu & Boopendranath, 1981). This species is ovoviviparous (matrotrophic viviparious) (Herbert, 2012). A single pup follows a gestation period of approximently one year, (Marshall et al., 2008, Mendonça et al., 2012). Sucessive pregnancies are speculated to be separated by a refactory period of two or more years (Mendonça et al., 2012). The objective of this study is to record the measurements of a M. birostris fetus of a female caught accidentally in the region of Tumbes, Peru. This is the first record of morphological and morphometric data regarding a manta fetus in Peru.
The population of Mobula birostris (“giant manta ray”) found in the waters of northern Peru and E... more The population of Mobula birostris (“giant manta ray”) found in the waters of northern Peru and Ecuador is believed to be the largest in the world (Harding & Beirwagen, 2009). This species is considered to be the largest within the group of manta rays, as they attains at least 670 cm disc width (reported to 910 cm) (White et al., 2006) and there is a record of an individual weighing 2000 kg (Kunjipalu & Boopendranath, 1981). This species is ovoviviparous (matrotrophic viviparious) (Herbert, 2012). A single pup follows a gestation period of approximently one year, (Marshall et al., 2008, Mendonça et al., 2012). Sucessive pregnancies are speculated to be separated by a refactory period of two or more years (Mendonça et al., 2012). The objective of this study is to record the measurements of a M. birostris fetus of a female caught accidentally in the region of Tumbes, Peru. This is the first record of morphological and morphometric data regarding a manta fetus in Peru.
We test the use of hyperspectral sensors for the early detection of the invasive denseflowered co... more We test the use of hyperspectral sensors for the early detection of the invasive denseflowered cordgrass (Spartina densiflora Brongn.) in the Guadalquivir River marshes, Southwestern Spain. We flew in tandem a CASI-1500 (368-1052 nm) and an AHS (430-13,000 nm) airborne sensors in an area with presence of S. densiflora. We simplified the processing of hyperspectral data (no atmospheric correction and no data-reduction techniques) to test if these treatments were necessary for accurate S. densiflora detection in the area. We tested several statistical signal detection algorithms implemented in ENVI software as spectral target detection techniques (matched filtering, constrained energy minimization, orthogonal subspace projection, target-constrained interference minimized filter, and adaptive coherence estimator) and compared them to the well-known spectral angle mapper, using spectra extracted from ground-truth locations in the images. The target S. densiflora was easy to detect in the marshes by all algorithms in images of both sensors. The best methods (adaptive coherence estimator and target-constrained interference minimized filter) on the best sensor (AHS) produced 100% discrimination (Kappa = 1, AUC = 1) at the study site and only some decline in performance when extrapolated to a new nearby area. AHS outperformed CASI in spite of having a coarser spatial resolution (4-m vs. 1-m) and lower spectral resolution in the visible and near-infrared range, but had a better signal to noise ratio. The larger spectral range of AHS in the shortwave and thermal infrared was of no particular advantage. Our conclusions are that it is possible to use hyperspectral sensors to map the early spread S. densiflora in the Guadalquivir River marshes. AHS is the most suitable airborne hyperspectral sensor for this task and the signal processing techniques target-constrained interference minimized filter (TCIMF) and adaptive coherence estimator (ACE) are the best performing target detection techniques that can be employed operationally with a simplified processing of hyperspectral images.
In the developing world, most patients with hepatocellular carcinoma present with advanced-stage ... more In the developing world, most patients with hepatocellular carcinoma present with advanced-stage disease, considered to be incurable based on current therapeutic algorithms. Here, we demonstrate that curative liver resection is achievable in a portion of Peruvian patients not addressed by these treatment algorithms. We conducted a retrospective cohort study of 253 hepatocellular carcinoma patients that underwent a curative hepatectomy between 1991 and 2011 at the National Cancer Institute of Peru. The median age of the cohort was
semestre de 2006. La actividad con los niños inicia con una tabla construida a partir del número ... more semestre de 2006. La actividad con los niños inicia con una tabla construida a partir del número 1, sumando consecutivamente 0, 1, 2, etc., las sumas parciales de esta tabla, nos dan otra tabla cuyos elementos son los números poligonales; fijamos nuestra atención sobre los números triangulares, en particular cuando las sumas de algunos de ellos también es un número triangular.
Background: Gastric cancer (GC) is the fourth most common cause of cancer deaths around the world... more Background: Gastric cancer (GC) is the fourth most common cause of cancer deaths around the world and the first cause of cancer deaths in Peru; however, there are no prospective trials for adjuvant chemotherapy in GC after curative gastrectomy in this country. The objective of this study was to evaluate the effectiveness of adjuvant chemotherapy in stage II-III gastric cancer patients who underwent D2 gastrectomy. Methods: We included patients with stage II-III gastric cancer who underwent radical gastrectomy and D2 dissection between 2014 and 2016 at our institution. Patients received 3-week cycles of capecitabine (1,000 mg/m² twice daily on days 1-14) plus oxaliplatin (130 mg/m² on day 1) for 6 months. Survival curves were estimated with the Kaplan-Meier method, and the Cox proportional hazards model was used to identify prognostic factors for survival. Results: In total, 173 patients were included: 100 (57.8%) patients received adjuvant chemotherapy and surgery (AChS) and 73 (42.2%) surgery alone (SA). Three-year diseasefree survival (DFS) was higher in the AChS groups (69%) than in the SA group (52.6%) (p = 0.034). Regarding overall survival (OS), 31 patients (31%) died in the AChS group compared with 34 (46.6%) in the SA group (p = 0.027). In the multivariate analysis, adjuvant chemotherapy was an independent prognostic factor for DFS (HR = 0.60; 95% CI = 0.37-0.97; p = 0.036) and OS (HR = 0.58; 95% CI = 0.36-0.95; p = 0.029). ACh showed consistent benefit in DFS and OS for patients with albumin >3.5 g/dL, lymphovascular and perineural invasion, pT4, pN2-3, pathologic stage (PS) IIIA and IIIB and lymph node ratio (LNR) > 13.1. Conclusion: These data suggest that adjuvant capecitabine and oxaliplatin reduce the recurrence and mortality in patients with stage II-III gastric cancer who underwent D2 gastrectomy. PS IIIA and IIIB and LNR > 13.1 benefited more from receiving adjuvant chemotherapy and poorly cohesive gastric carcinoma did not significantly reduce the rates of survival.
Revista de gastroenterologia del Peru : organo oficial de la Sociedad de Gastroenterologia del Peru, 2012
Identify prognostic factors associated to total or proximal gastrectomy with or without splenecto... more Identify prognostic factors associated to total or proximal gastrectomy with or without splenectomy and / or distal pancreatectomy in patient with proximal gastric cancer. Evaluate the frequency of lymph node metastasis to the hilum and splenic artery, postoperative morbidity and mortality and the impact of lymphadenectomy of group 10 and 11 on long term survival. We performed an observational, descriptive, longitudinal and retrospective study analyzing patients with diagnostic of proximal third gastric adenocarcinoma subjected to total or proximal gastrectomy with or without splenectomy or distal pancreatectomy in the service of Abdomen of the Instituto Nacional de Enfermedades Neoplásicas between 1990 and 2005. Overall survival for each of the groups was calculated using the Kaplan-Meier method, prognostic factors were evaluated using univariate and multivariate analysis. We studied 219 patients with proximal third gastric adenocarcinoma (cardias and bottom), of wich, according to inclusion criteria, only qualify 129 (N=129): 22 (17.1%) were treated by gastrectomy alone, 79 (61.2%) gastrectomy associated witch splenectomy and 28 (21.7%) gastrectomy with distal pancreatosplenectomy, constituting three treatment groups. We compared the survival of each group and each factor analyzed, determining the following prognostic factors: lymph node metastasis (N2-N3), degree of differentiation, undifferentiated tumors and Borrmann III and IV tumors. Neither splenectomy or distal pancreatectosplenectomy improved survival compared to the gastrectomy alone. The morbidity and mortality was higher in patients with more aggressive but more aggressive surgery without significant value. The number of nodes removed in patients who had pancreatosplenectomy and /or splenectomy was higher, however, had no impact on survival at 5 years.
2016. Bancos naturales de invertebrados bentónicos comerciales y zonas de pesca artesanal. Tumbes... more 2016. Bancos naturales de invertebrados bentónicos comerciales y zonas de pesca artesanal. Tumbes, Perú. Otoño 2014. Inf Inst Mar Perú. 43(3): 275-297.-Se efectuó evaluación biológica y oceanográfica en bancos naturales (intermareales y submareales) del litoral de Tumbes del 24 de mayo al 20 de junio 2014. En el intermareal se evaluaron 31 estaciones, y en el submareal 186 estaciones, mediante buceo semiautónomo; temperatura, pH y oxígeno disuelto (OD) tuvieron valores homogéneos. En el intermareal arenoso se identificaron bancos naturales de palabritas Donax dentifer y D. obesulus; en el rocoso, parches de ostra Crassostrea iridescens y percebe Pollicipes elegans. En el submareal rocoso se registraron bancos naturales de ostra Crassostrea iridescens y pulpo Octopus mimus; en fondos blandos se apreciaron parches de Chione amathusia y Tellina sp.; los moluscos y crustáceos presentaron mayor número de especies. En esta zona, la pendiente del relieve submarino aumentó de norte a sur, p...
En el seminario de algebra de la Universidad Pedagogica Nacional orientado por el grupo de algebr... more En el seminario de algebra de la Universidad Pedagogica Nacional orientado por el grupo de algebra, estamos interesados en estudiar el proceso matematico de Analizar, que involucra descomponer elementos de una estructura en elementos distinguidos de la misma, un ejemplo de esto es la descomposicion en factores primos en el conjunto de los naturales, sin embargo, cuando se indaga sobre la demostracion del teorema fundamental de la aritmetica, por lo general se encuentra que involucra a los enteros, lo que lleva a cuestionar si este se puede demostrarse en los naturales a partir de una de sus axiomaticas; esta pregunta se traslado a los participantes del seminario en el 2013, en esta propuesta se presentan algunos resultados obtenidos.
Se presenta la interpretacion que el grupo de Algebra de la Universidad Pedagogica Nacional tiene... more Se presenta la interpretacion que el grupo de Algebra de la Universidad Pedagogica Nacional tiene del proceso matematico de analizar, caracterizando las dos formas en las que este se utiliza para estudiar una estructura algebraica, a saber el analisis de una estructura y en la estructura, y mostrando ejemplos de anillos en los que el concepto de divisibilidad permite abordar actividades en las que se explicita el proceso de analizar bajo su segunda forma.
Thermography enables non-invasive, accessible, and easily repeated foot temperature measurements ... more Thermography enables non-invasive, accessible, and easily repeated foot temperature measurements for diabetic patients, promoting early detection and regular monitoring protocols, that limit the incidence of disabling conditions associated with diabetic foot disorders. The establishment of this application into standard diabetic care protocols requires to overcome technical issues, particularly the foot sole segmentation. In this work we implemented and evaluated several segmentation approaches which include conventional and Deep Learning methods. Multimodal images, constituted by registered visual-light, infrared and depth images, were acquired for 37 healthy subjects. The segmentation methods explored were based on both visual-light as well as infrared images, and optimization was achieved using the spatial information provided by the depth images. Furthermore, a ground truth was established from the manual segmentation performed by two independent researchers. Overall, the perfor...
Management of constipation associated with advanced cancers, chemotherapy and opioid-induced cons... more Management of constipation associated with advanced cancers, chemotherapy and opioid-induced constipation by oral herbal supplement in heterogeneous group of gastrointestinal, hepatobiliary and pancreatic cancers
Los peces venenosos y tóxicos forman parte de la riqueza en biodiversidad del Perú, sus venenos y... more Los peces venenosos y tóxicos forman parte de la riqueza en biodiversidad del Perú, sus venenos y toxinas contienen metabolitos que pueden emplearse para producir sustancias farmacológicas. La investigación tuvo como objetivo identificar, mediante ADN barcoding, las especies de peces venenosos y tóxicos en el manglar de Tumbes. Se recolectaron 46 ejemplares de estos peces que fueron identificados morfológicamente. Para el análisis de ADN barcoding, se obtuvo sus secuencias de un fragmento del gen de la subunidad I de la citocromo oxidasa (COI), con las cuales se realizó su identificación en Blast y Bold. Se realizó el análisis filogenético mediante Neighbor joining (NJ), automatic barcode gap discovery (ABGD) y modelo generalizado mixto de Yule y coalescencia (GMYC), que confirmaron la asignación de especies. Mediante ADN barcoding se identificó las especies: Daector dowi, Diodon holocanthus, Sphoeroides andersonianus, S. annulatus, S. kendalli, S. sechurae, Gymnura marmorata, Urotrygon asterias y U. peruanus. En algunos ejemplares la identificación mediante ADN barcoding, caracteres morfológicos y análisis filogenético fueron disimiles como en los géneros Sphoeroides y Urotrygon, por lo que deberían realizarse más estudios para confirmar la presencia de complejos de especies altamente emparentadas en ellos.
2016. Bancos naturales de invertebrados bentónicos comerciales y zonas de pesca artesanal. Tumbes... more 2016. Bancos naturales de invertebrados bentónicos comerciales y zonas de pesca artesanal. Tumbes, Perú. Otoño 2014. Inf Inst Mar Perú. 43(3): 275-297.-Se efectuó evaluación biológica y oceanográfica en bancos naturales (intermareales y submareales) del litoral de Tumbes del 24 de mayo al 20 de junio 2014. En el intermareal se evaluaron 31 estaciones, y en el submareal 186 estaciones, mediante buceo semiautónomo; temperatura, pH y oxígeno disuelto (OD) tuvieron valores homogéneos. En el intermareal arenoso se identificaron bancos naturales de palabritas Donax dentifer y D. obesulus; en el rocoso, parches de ostra Crassostrea iridescens y percebe Pollicipes elegans. En el submareal rocoso se registraron bancos naturales de ostra Crassostrea iridescens y pulpo Octopus mimus; en fondos blandos se apreciaron parches de Chione amathusia y Tellina sp.; los moluscos y crustáceos presentaron mayor número de especies. En esta zona, la pendiente del relieve submarino aumentó de norte a sur, p...
Identificación mediante ADN barcode de peces invasores en el manglar de Tumbes (Perú) Identificat... more Identificación mediante ADN barcode de peces invasores en el manglar de Tumbes (Perú) Identification by DNA barcode of invading fish in the mangrove of Tumbes (Peru)
The population of Mobula birostris (“giant manta ray”) found in the waters of northern Peru and E... more The population of Mobula birostris (“giant manta ray”) found in the waters of northern Peru and Ecuador is believed to be the largest in the world (Harding & Beirwagen, 2009). This species is considered to be the largest within the group of manta rays, as they attains at least 670 cm disc width (reported to 910 cm) (White et al., 2006) and there is a record of an individual weighing 2000 kg (Kunjipalu & Boopendranath, 1981). This species is ovoviviparous (matrotrophic viviparious) (Herbert, 2012). A single pup follows a gestation period of approximently one year, (Marshall et al., 2008, Mendonça et al., 2012). Sucessive pregnancies are speculated to be separated by a refactory period of two or more years (Mendonça et al., 2012). The objective of this study is to record the measurements of a M. birostris fetus of a female caught accidentally in the region of Tumbes, Peru. This is the first record of morphological and morphometric data regarding a manta fetus in Peru.
The population of Mobula birostris (“giant manta ray”) found in the waters of northern Peru and E... more The population of Mobula birostris (“giant manta ray”) found in the waters of northern Peru and Ecuador is believed to be the largest in the world (Harding & Beirwagen, 2009). This species is considered to be the largest within the group of manta rays, as they attains at least 670 cm disc width (reported to 910 cm) (White et al., 2006) and there is a record of an individual weighing 2000 kg (Kunjipalu & Boopendranath, 1981). This species is ovoviviparous (matrotrophic viviparious) (Herbert, 2012). A single pup follows a gestation period of approximently one year, (Marshall et al., 2008, Mendonça et al., 2012). Sucessive pregnancies are speculated to be separated by a refactory period of two or more years (Mendonça et al., 2012). The objective of this study is to record the measurements of a M. birostris fetus of a female caught accidentally in the region of Tumbes, Peru. This is the first record of morphological and morphometric data regarding a manta fetus in Peru.
We test the use of hyperspectral sensors for the early detection of the invasive denseflowered co... more We test the use of hyperspectral sensors for the early detection of the invasive denseflowered cordgrass (Spartina densiflora Brongn.) in the Guadalquivir River marshes, Southwestern Spain. We flew in tandem a CASI-1500 (368-1052 nm) and an AHS (430-13,000 nm) airborne sensors in an area with presence of S. densiflora. We simplified the processing of hyperspectral data (no atmospheric correction and no data-reduction techniques) to test if these treatments were necessary for accurate S. densiflora detection in the area. We tested several statistical signal detection algorithms implemented in ENVI software as spectral target detection techniques (matched filtering, constrained energy minimization, orthogonal subspace projection, target-constrained interference minimized filter, and adaptive coherence estimator) and compared them to the well-known spectral angle mapper, using spectra extracted from ground-truth locations in the images. The target S. densiflora was easy to detect in the marshes by all algorithms in images of both sensors. The best methods (adaptive coherence estimator and target-constrained interference minimized filter) on the best sensor (AHS) produced 100% discrimination (Kappa = 1, AUC = 1) at the study site and only some decline in performance when extrapolated to a new nearby area. AHS outperformed CASI in spite of having a coarser spatial resolution (4-m vs. 1-m) and lower spectral resolution in the visible and near-infrared range, but had a better signal to noise ratio. The larger spectral range of AHS in the shortwave and thermal infrared was of no particular advantage. Our conclusions are that it is possible to use hyperspectral sensors to map the early spread S. densiflora in the Guadalquivir River marshes. AHS is the most suitable airborne hyperspectral sensor for this task and the signal processing techniques target-constrained interference minimized filter (TCIMF) and adaptive coherence estimator (ACE) are the best performing target detection techniques that can be employed operationally with a simplified processing of hyperspectral images.
In the developing world, most patients with hepatocellular carcinoma present with advanced-stage ... more In the developing world, most patients with hepatocellular carcinoma present with advanced-stage disease, considered to be incurable based on current therapeutic algorithms. Here, we demonstrate that curative liver resection is achievable in a portion of Peruvian patients not addressed by these treatment algorithms. We conducted a retrospective cohort study of 253 hepatocellular carcinoma patients that underwent a curative hepatectomy between 1991 and 2011 at the National Cancer Institute of Peru. The median age of the cohort was
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Papers by Carlos Luque