Ludwig Naegel | Instituto Politécnico Nacional (original) (raw)

Papers by Ludwig Naegel

Dyes and Pigments, 2012

ABSTRACT Atmospheric Pressure Photoionization (APPI) in Mass Spectrometry (MS) has been utilized ... more ABSTRACT Atmospheric Pressure Photoionization (APPI) in Mass Spectrometry (MS) has been utilized for a number of indigo-related compounds and was found to exhibit an excellent response. All structures were ionized 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 reference 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.

4th International Symposium on Tilapia i Aquaculture

The production of tilapias has increased steadily in the last decades, making this fish family on... more The production of tilapias has increased steadily in the last decades, making this fish family one of the most important for aquaculture. Commercial enterprises are using for their tilapia production, compounded, pelleted fish feed with a high percentage of expensive fish meal, which subsistence farmers cannot afford. To increase the production of tilapias at the small-scale farmer level for home consumption and for earning an additional income for sales at local markets, the search for feed ingredients which could replace fish meal, and grown on their farm or locally available, is becoming a crucial issue. The inclusion of Azolla meal, a water fern with a relatively high protein content and grown together with rice, could replace part of the expensive fish meal, and could provide a farm-made supplemental feed of low cost for small-scale farmers. Azolla meal, from four different varieties and in four different concentrations, was incorporated into a compounded-pelleted feed used as a supplemental feed for all-male tilapia (Oreochromis niloticus) culture. Growth rates differed significantly between the Azolla varieties and concentrations tested. Introduction:

CICIMAR Oceanides

The coastal lagoon system Bahía Magdalena / Almejas (BM/A) at the Pacific coast of Baja Califor-n... more The coastal lagoon system Bahía Magdalena / Almejas (BM/A) at the Pacific coast of Baja Califor-nia Sur, México, is a large water body extremely important for ecological, economic and social reasons. Because of its natural environment BM/A was declared as one of the areas deserving marine conservation priority. The exact number of fishermen and their families living around the Bay is not known, and neither is the currently registered small boats in service, nor the fishing efforts, expenses and yields. Recently, several civil organizations started working in the BM/A with the mission to solve some of the identified environmental and social problems. However, because of the lack of reliable data, wide spread corruption, and undirected and uncoordinated research make it very difficult to suggest ways to improve the livelihood of the small-scale shrimp fishermen without endangering the environment. Some promising options are small-scale aquaculture projects, mainly for offshore mollusks production, and to offer eco-tourist activities as well as eco-friendly sport fishing. Both bring local employment opportunities while maintaining a quality environment. En busca de sustentabilidad de la pesquería de camarón a baja escala en el sistema lagunar Magdalena-Almejas Baja California Sur, México: una revisión RESUMEN. El sistema lagunar Bahía Magdalena / Almejas (BM/A) ubicado en la costa oeste de Baja California Sur, México, es un cuerpo de agua de extrema importancia bajo las perspectivas ecológica, económica y social. Dado su ambiente natural, BM/A es considerada un área prioritaria en términos de conservación marina. Se desconoce cuántas familias de pescadores viven entorno a la bahía, así como el número registrado de embarcacio-nes pequeñas en activo, el esfuerzo pesquero, sus gastos, o su rendimiento. Recientemente, varias organizaciones civiles comenzaron labores en BM/A bajo la consigna de resolver algunos de los problemas ambientales y sociales identificados. Sin embargo, debido a la falta de datos confiables y a la corrupción, aunados a investigación mal dirigida y sin coordinación, dificultan la posibilidad de sugerir maneras de mejorar la sustentabilidad de la pesca menor de camarón sin poner en riesgo el ambiente. Algunas alternativas prometedoras son los proyectos acuacul-turales a pequeña escala, principalmente para producción de moluscos lejos de la costa, así como las actividades ecoturísticas y la pesca deportiva ecológicamente amigable, dado que ambas abren oportunidades de empleo locales conservando la calidad del ambiente. Palabras clave: Bahía Magdalena/Almejas, conservación, pesca de camarón, sustentabilidad ambiental Naegel, L., M. Muñoz-Ochoa & L. Ma. Durán-Riveroll. 2016. Small-scale shrimp fishing in search of sustainability in the Magdalena-Almejas lagoon system, Baja California Sur, México: a review. CICIMAR Oceánides, 31(1): 43-54.

Panorama Acuicola, 2008

The academic programs in aquaculure often are not considering the neeeds and problems of the priv... more The academic programs in aquaculure often are not considering the neeeds and problems of the private industry

Jaspers Verlag. Munich, Germany, 1998

The stream driven spirl pump allows the most efficient energy use of a given stream flow for pum... more The stream driven spirl pump allows the most efficient energy use of a given stream flow for pumping purposes. The spiral pump has come to be considered by the farmers of Abra, Philippines,as a "Gift from God".

Jaspers Verlag, 2001

A controlled-environment greenhouse hss been designede for plant production in an efficient and e... more A controlled-environment greenhouse hss been designede for plant production in an efficient and environmentally friendly manner for arid areas with saltwater resources and high solar radiation

Aquaculture, 1977

A pilot plant o f ca 2000 1 o f recirculating fresh water fo r intensive fish p rod u ction was c... more A pilot plant o f ca 2000 1 o f recirculating fresh water fo r intensive fish p rod u ction was constructed in a controlled-environm ent greenhouse. T he feasibility was exam ined o f using nutrients from fish waste-water, mainly ox id ized nitrogenous com pou n d s, for plant p rod u c tion, com b in ed with an activated sludge system fo r water purification. T he red u ction o f nitrates, form ed during the extended aeration process b y nitrifying bacteria, was n ot sufficient b y higher plants and unicellular algae alone to reduce the nitrate con cen tration in our system significantly. A n additional m icrobial denitrification step had to be included to e ffe ct m axim al decrease in nitrogenous com pounds. F or fish culture in the pilot plant Tilapia mossambica and Cyprinus carpió were chosen as experim ental fishes. B oth fish species show ed significant weight increases during the course o f the experim ent. Ice-lettuce and tom atoes were tested b o th in recirculating water and in batch culture. T h e unicellular algae Scenedesm us spp. were grow n in a non-sterile batch culture. A ll plants grew well in the waste-water w ith out additional nutrients. D eterm ination o f the physical and Chemical parameters fo r optim um water purification, the m ost suitable ratio o f denitrification b y plants and b y m icroorganism s, and the m ost favourable fish and plant species for com bin ed culture in recirculating water are im portant and o f current interest in view o f the increasing demand for clean, fresh water, and the pressing need to find new ways o f producing protein for human nutrition under prevailing con dition s o f an exponentially expanding w orld population.

Aquaculture International, 1994

The integration of aquaculture into agricultural production systemw to intensify profitable food ... more The integration of aquaculture into agricultural production systemw to intensify profitable food production without the usual environmental degradaion appears to be a promising option for a large number of small farmers in developing countries. The multifaceted obstacles to developing a sustainable integrated aquafarming system are presented for a case in the Philippines.

Waterlines, 1991

New experiments on an old ideas have determined the ideal conditions for achieving maximum effici... more New experiments on an old ideas have determined the ideal conditions for achieving maximum efficiency from a spiral pump

J. Shellfish Research, 2006

ABSTRAeT Marked, sized and ,ex determined purple snails Plicopurpura pansa, (Oould, 1853) were di... more ABSTRAeT Marked, sized and ,ex determined purple snails Plicopurpura pansa, (Oould, 1853) were distributed randomly among other snails in crevices of an intertidal rocky island splashed during high tides by high impact waves. After 89 days 18%, after 117 days 12%, after 145 days 8% and after 183 days only 3% of ¡he marked snaíls could be recovered. There was no statistícally significant difference between size and sex and the recovery rateo In the laboratory we determined the lime needed for reattachment 10 the surface under different situations. Snails placed with the aperture down on a we! surface or in water reattached themselves after about 20 min, snails placed in water on their backs; in abou! 40 min, and snalls left on a wet surface on their backs after 2 hours. After 4 hours only 50% of the snails placed on their backs in a wet surface were found to be reattached. Oreat differences were noticed in the period needed for reattachment among individual snails. The time needed for the snalls to overcome the stress of being detached from Ihe surface and 10 reattach themselves again can be blamed for the los8 of animals during the increasing incoming tides eombined with the high impae! wave actions. The prohibirion of "milking" P. pansa 10 obtaln 'Tyrian Purple" and to colleet the snails as a bait for físhery or as a special food for foreigners should be enforced and should be extended to the removal Ihe snails from the crevices of illtertidal rocks.

Animal Research and Development, 1998

Field experiments with different Azolla varieties as feed for tilapias showed excellent results.

Animal Research and Development, 1998

Use of Azol;la as a feed ingredient for tilapias

Ciencias Marinas, 2004

Embriogénesis y desarrollo larvario intra-capsular de Plicopurpura pansa (Gould, 1853) (Prosobran... more Embriogénesis y desarrollo larvario intra-capsular de Plicopurpura pansa (Gould, 1853) (Prosobranchia, Muricidae) en condiciones de laboratorio

Ciencias Marinas, 2004

Embriogénesis y desarrollo larvario intra-capsular de Plicopurpura pansa (Gould, 1853) (Prosobran... more Embriogénesis y desarrollo larvario intra-capsular de Plicopurpura pansa (Gould, 1853) (Prosobranchia, Muricidae) en condiciones de laboratorio

Hannover, T. U., F. f. Math. u. Naturwiss., Diss. v. 6. Juli 1968.

Dyes and Pigments, 2012

ABSTRACT Atmospheric Pressure Photoionization (APPI) in Mass Spectrometry (MS) has been utilized ... more ABSTRACT Atmospheric Pressure Photoionization (APPI) in Mass Spectrometry (MS) has been utilized for a number of indigo-related compounds and was found to exhibit an excellent response. All structures were ionized 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 reference 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.

4th International Symposium on Tilapia i Aquaculture

The production of tilapias has increased steadily in the last decades, making this fish family on... more The production of tilapias has increased steadily in the last decades, making this fish family one of the most important for aquaculture. Commercial enterprises are using for their tilapia production, compounded, pelleted fish feed with a high percentage of expensive fish meal, which subsistence farmers cannot afford. To increase the production of tilapias at the small-scale farmer level for home consumption and for earning an additional income for sales at local markets, the search for feed ingredients which could replace fish meal, and grown on their farm or locally available, is becoming a crucial issue. The inclusion of Azolla meal, a water fern with a relatively high protein content and grown together with rice, could replace part of the expensive fish meal, and could provide a farm-made supplemental feed of low cost for small-scale farmers. Azolla meal, from four different varieties and in four different concentrations, was incorporated into a compounded-pelleted feed used as a supplemental feed for all-male tilapia (Oreochromis niloticus) culture. Growth rates differed significantly between the Azolla varieties and concentrations tested. Introduction:

CICIMAR Oceanides

The coastal lagoon system Bahía Magdalena / Almejas (BM/A) at the Pacific coast of Baja Califor-n... more The coastal lagoon system Bahía Magdalena / Almejas (BM/A) at the Pacific coast of Baja Califor-nia Sur, México, is a large water body extremely important for ecological, economic and social reasons. Because of its natural environment BM/A was declared as one of the areas deserving marine conservation priority. The exact number of fishermen and their families living around the Bay is not known, and neither is the currently registered small boats in service, nor the fishing efforts, expenses and yields. Recently, several civil organizations started working in the BM/A with the mission to solve some of the identified environmental and social problems. However, because of the lack of reliable data, wide spread corruption, and undirected and uncoordinated research make it very difficult to suggest ways to improve the livelihood of the small-scale shrimp fishermen without endangering the environment. Some promising options are small-scale aquaculture projects, mainly for offshore mollusks production, and to offer eco-tourist activities as well as eco-friendly sport fishing. Both bring local employment opportunities while maintaining a quality environment. En busca de sustentabilidad de la pesquería de camarón a baja escala en el sistema lagunar Magdalena-Almejas Baja California Sur, México: una revisión RESUMEN. El sistema lagunar Bahía Magdalena / Almejas (BM/A) ubicado en la costa oeste de Baja California Sur, México, es un cuerpo de agua de extrema importancia bajo las perspectivas ecológica, económica y social. Dado su ambiente natural, BM/A es considerada un área prioritaria en términos de conservación marina. Se desconoce cuántas familias de pescadores viven entorno a la bahía, así como el número registrado de embarcacio-nes pequeñas en activo, el esfuerzo pesquero, sus gastos, o su rendimiento. Recientemente, varias organizaciones civiles comenzaron labores en BM/A bajo la consigna de resolver algunos de los problemas ambientales y sociales identificados. Sin embargo, debido a la falta de datos confiables y a la corrupción, aunados a investigación mal dirigida y sin coordinación, dificultan la posibilidad de sugerir maneras de mejorar la sustentabilidad de la pesca menor de camarón sin poner en riesgo el ambiente. Algunas alternativas prometedoras son los proyectos acuacul-turales a pequeña escala, principalmente para producción de moluscos lejos de la costa, así como las actividades ecoturísticas y la pesca deportiva ecológicamente amigable, dado que ambas abren oportunidades de empleo locales conservando la calidad del ambiente. Palabras clave: Bahía Magdalena/Almejas, conservación, pesca de camarón, sustentabilidad ambiental Naegel, L., M. Muñoz-Ochoa & L. Ma. Durán-Riveroll. 2016. Small-scale shrimp fishing in search of sustainability in the Magdalena-Almejas lagoon system, Baja California Sur, México: a review. CICIMAR Oceánides, 31(1): 43-54.

Panorama Acuicola, 2008

The academic programs in aquaculure often are not considering the neeeds and problems of the priv... more The academic programs in aquaculure often are not considering the neeeds and problems of the private industry

Jaspers Verlag. Munich, Germany, 1998

The stream driven spirl pump allows the most efficient energy use of a given stream flow for pum... more The stream driven spirl pump allows the most efficient energy use of a given stream flow for pumping purposes. The spiral pump has come to be considered by the farmers of Abra, Philippines,as a "Gift from God".

Jaspers Verlag, 2001

A controlled-environment greenhouse hss been designede for plant production in an efficient and e... more A controlled-environment greenhouse hss been designede for plant production in an efficient and environmentally friendly manner for arid areas with saltwater resources and high solar radiation

Aquaculture, 1977

A pilot plant o f ca 2000 1 o f recirculating fresh water fo r intensive fish p rod u ction was c... more A pilot plant o f ca 2000 1 o f recirculating fresh water fo r intensive fish p rod u ction was constructed in a controlled-environm ent greenhouse. T he feasibility was exam ined o f using nutrients from fish waste-water, mainly ox id ized nitrogenous com pou n d s, for plant p rod u c tion, com b in ed with an activated sludge system fo r water purification. T he red u ction o f nitrates, form ed during the extended aeration process b y nitrifying bacteria, was n ot sufficient b y higher plants and unicellular algae alone to reduce the nitrate con cen tration in our system significantly. A n additional m icrobial denitrification step had to be included to e ffe ct m axim al decrease in nitrogenous com pounds. F or fish culture in the pilot plant Tilapia mossambica and Cyprinus carpió were chosen as experim ental fishes. B oth fish species show ed significant weight increases during the course o f the experim ent. Ice-lettuce and tom atoes were tested b o th in recirculating water and in batch culture. T h e unicellular algae Scenedesm us spp. were grow n in a non-sterile batch culture. A ll plants grew well in the waste-water w ith out additional nutrients. D eterm ination o f the physical and Chemical parameters fo r optim um water purification, the m ost suitable ratio o f denitrification b y plants and b y m icroorganism s, and the m ost favourable fish and plant species for com bin ed culture in recirculating water are im portant and o f current interest in view o f the increasing demand for clean, fresh water, and the pressing need to find new ways o f producing protein for human nutrition under prevailing con dition s o f an exponentially expanding w orld population.

Aquaculture International, 1994

The integration of aquaculture into agricultural production systemw to intensify profitable food ... more The integration of aquaculture into agricultural production systemw to intensify profitable food production without the usual environmental degradaion appears to be a promising option for a large number of small farmers in developing countries. The multifaceted obstacles to developing a sustainable integrated aquafarming system are presented for a case in the Philippines.

Waterlines, 1991

New experiments on an old ideas have determined the ideal conditions for achieving maximum effici... more New experiments on an old ideas have determined the ideal conditions for achieving maximum efficiency from a spiral pump

J. Shellfish Research, 2006

ABSTRAeT Marked, sized and ,ex determined purple snails Plicopurpura pansa, (Oould, 1853) were di... more ABSTRAeT Marked, sized and ,ex determined purple snails Plicopurpura pansa, (Oould, 1853) were distributed randomly among other snails in crevices of an intertidal rocky island splashed during high tides by high impact waves. After 89 days 18%, after 117 days 12%, after 145 days 8% and after 183 days only 3% of ¡he marked snaíls could be recovered. There was no statistícally significant difference between size and sex and the recovery rateo In the laboratory we determined the lime needed for reattachment 10 the surface under different situations. Snails placed with the aperture down on a we! surface or in water reattached themselves after about 20 min, snails placed in water on their backs; in abou! 40 min, and snalls left on a wet surface on their backs after 2 hours. After 4 hours only 50% of the snails placed on their backs in a wet surface were found to be reattached. Oreat differences were noticed in the period needed for reattachment among individual snails. The time needed for the snalls to overcome the stress of being detached from Ihe surface and 10 reattach themselves again can be blamed for the los8 of animals during the increasing incoming tides eombined with the high impae! wave actions. The prohibirion of "milking" P. pansa 10 obtaln 'Tyrian Purple" and to colleet the snails as a bait for físhery or as a special food for foreigners should be enforced and should be extended to the removal Ihe snails from the crevices of illtertidal rocks.

Animal Research and Development, 1998

Field experiments with different Azolla varieties as feed for tilapias showed excellent results.

Animal Research and Development, 1998

Use of Azol;la as a feed ingredient for tilapias

Ciencias Marinas, 2004

Embriogénesis y desarrollo larvario intra-capsular de Plicopurpura pansa (Gould, 1853) (Prosobran... more Embriogénesis y desarrollo larvario intra-capsular de Plicopurpura pansa (Gould, 1853) (Prosobranchia, Muricidae) en condiciones de laboratorio

Ciencias Marinas, 2004

Embriogénesis y desarrollo larvario intra-capsular de Plicopurpura pansa (Gould, 1853) (Prosobran... more Embriogénesis y desarrollo larvario intra-capsular de Plicopurpura pansa (Gould, 1853) (Prosobranchia, Muricidae) en condiciones de laboratorio

Hannover, T. U., F. f. Math. u. Naturwiss., Diss. v. 6. Juli 1968.

Jaspers Verlag, Munich, Germany2001, 2001

Aquaculture production becomes more and mor importantg for food supply especially in the tropics ... more Aquaculture production becomes more and mor importantg for food supply especially in the tropics and subtropics

Jaspers Verlag, Munich, 2001

The use of solar energy for the dasalination in sallwater greenhuases is becoming important in ar... more The use of solar energy for the dasalination in sallwater greenhuases is becoming important in arid regions close to marine waters.