http://repositoriodigital.ipn.mx/handle/123456789/2942 Sat, 18 Apr 2026 14:55:28 GMT 2026-04-18T14:55:28Z http://repositoriodigital.ipn.mx/handle/123456789/13719 Title: Occurrence of Pyrodinium bahamense var. compressum along the southern coast of the Baja California Peninsula Authors: Gárate Lizárraga, Ismael; González Armas, Rogelio Abstract: As part of a continuing toxic microalgae monitoring program, 22 phytoplankton samples were collected from July to November 2010 at several sampling stations along the southern coast of the Baja California Peninsula. For the first time, the toxic dinoflagellate Pyrodinium bahamense var. compressum was found along the southeastern and southwestern coasts of the peninsula. P. bahamense var. bahamense was first observed off San José del Cabo, which is an extension of the range of this variety. Both varieties occur as solitary cells. P. bahamense var. compressum occurred at temperatures ranging between 24.5 °C and 31 °C, whereas var. P. bahamense occurred at 28.5 °C to 29°C, indicating its tropical and subtropical nature. Occurrence of P. bahamense var. compressum along this coastline may be related to El Niño 2009–2010. Sat, 01 Jan 2011 00:00:00 GMT http://repositoriodigital.ipn.mx/handle/123456789/13719 2011-01-01T00:00:00Z http://repositoriodigital.ipn.mx/handle/123456789/13718 Title: Developing a non-invasive indicator of pinniped health: Neonate behavior and growth in california sea lions (Zalophus californianus) Authors: Green, David S.; Young, Julie K.; Hernández Camacho, Claudia Janetl; Gerber, Leah Abstract: Assessing the health of wildlife populations is critical to achieving conservation goals. However, proper assessments can be complicated when study sites are difficult to reach or when focal species are sensitive to human disturbance. Condition and growth of offspring may indicate population health, but obtaining such data generally relies on invasive techniques. Here, we examine the extent to which non-invasive observations of neonate behaviors could serve as a proxy for traditional approaches to estimating neonate body condition and growth of a wild pinniped, the California sea lion (Zalophus californianus), in the Gulf of California, Mexico. Generalized linear models and multiple linear regressions were used to examine the effect of sex, breeding island, year, and neonate behaviors (e.g., nursing, active) on body condition and growth rates. We found a strong correlation between individual growth rates and behaviors of male neonates. Males engaged in proportionally more active behaviors had lower growth rates (β = -0.0005), whereas males engaged in proportionally more nursing events had higher growth rates (β = 0.002). There was no relationship between neonate behavior and condition for either sex pup nor between behavior and growth rates of female pups. These results provide insight into the possibility of using behavior as an indicator of individual status of males that could facilitate assessments of population status, and illustrate the importance of using alternative approaches to measure animal condition for species conservation. Fri, 01 Jan 2010 00:00:00 GMT http://repositoriodigital.ipn.mx/handle/123456789/13718 2010-01-01T00:00:00Z http://repositoriodigital.ipn.mx/handle/123456789/13715 Title: Analysis of indigo-type compounds in natural dyes by negative ion atmospheric pressure photoionization mass spectrometry Authors: Papanastasiou, Malvina; Allen, Norman S.; McMahon, Adam; Naegel, Ludwig C.A.; Edge, Michele; Protopappas, Stavros Abstract: Atmospheric Pressure Photoionization (APPI) in Mass Spectrometry (MS) has been utilized for a lumber of indigo-related compounds and was found to exhibit an excellent response. All structures were ionizad in negative ion mode yielding almost exclusively deprotonated molecules. Their product ion mass spectra were also recorded and showed characteristic losses mainly of small neutrals such as CO, HBr and CONH2. APPI-MS was applied further to the analysis of indigo dyestuffs of historical importance. HPLC with single ion monitoring (SIM) was employed for the separation and detection of the compounds. A simple HPLC gradient that separated the components in less than 10 min was developed. MS/MS spectra of the colouring components were also recorded and compared to that of the referente substances. The composition of Tyrian purple originating from Murex trunculus (Hexaplex trunculus), was by far the most complex, whereas some of the structures were also detected in Purpura haemastoma (Stramonita haemastoma) and Plicopurpura pansa (Plicopurpura patula subs. pansa). Further, a number of synthetic indigo dyes, produced at different times of the 19thcentury by different manufacturers, were analyzed; similar spectra were obtained suggesting that these were highly pure. Overall, the developed analytical procedure was very efficient offering high sensitivity and selectivity. APPI was proved suitable for ionizing the species under investigation producing clear mass spectra with characteristic fragment ions and may be used successfully in the future for the characterization of similar structures in historical art objects. Sun, 01 Jan 2012 00:00:00 GMT http://repositoriodigital.ipn.mx/handle/123456789/13715 2012-01-01T00:00:00Z http://repositoriodigital.ipn.mx/handle/123456789/13714 Title: Cambios temporales en asociaciones de diatomeas bentónicas en estanques de cultivo de camarón Authors: Siqueiros Beltrones, David Alfaro; Acevedo González, Avryl Abstract: Aunque las diatomeas bentónicas forman parte de la dieta de los camarones, las asociaciones de diatomeas que proliferan en los fondos de los estanques donde habita el camarón no habían sido estudiadas. Dado que los estanques son manipulados para mantener constantes las características del fitoplancton, se contrastaron las hipótesis de que: 1) una sola asociación de diatomeas bentónicas se mantendría durante un ciclo de cultivo y 2) que esta sería distinta de las del ambiente natural. Así, nuestro objetivo fué determinar la variación espacial y temporal de las asociaciones de diatomeas bentónicas bajo condiciones típicas de producción. Se examinaron muestras mensuales (junio–octubre) de fondo y de arrastre. Se identificaron 100 taxa de diatomeas bentónicas de 46 géneros; los más representativos fueron: Nitzschia (9 especies), Amphora (7) y Navicula (6). La diversidad varió de H’=1.5 en junio a H’= 4.3 en septiembre y octubre. En muestras de arrastre el 70% fueron formas ticoplanctónicas. Se distinguieron dos asociaciones, una en junio y julio, con mayor dominancia y menor riqueza de especies y caracterizada por Amphora coffeaeformis var. salina y Catacombas gaillioni; y otra, de septiembre y octubre, caracterizada por Navicula cryptocephala var. subsalina y Neodelphineis pelágica, aunado a la disminución de los taxa anteriores. Las asociaciones mostraron variación similar al de ambientes naturales someros eutrofizados, i.e., cambios en estructura de la asociación de verano a la de otoño, lo que refuta las hipótesis planteadas. Fri, 01 Jan 2010 00:00:00 GMT http://repositoriodigital.ipn.mx/handle/123456789/13714 2010-01-01T00:00:00Z