• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 12
  • 10
  • 2
  • 2
  • 2
  • 2
  • 1
  • 1
  • Tagged with
  • 44
  • 10
  • 10
  • 9
  • 7
  • 7
  • 7
  • 7
  • 7
  • 7
  • 6
  • 5
  • 5
  • 5
  • 5
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Estudio de los efectos del índice de oxígeno sobre las propiedades de una llama de difusión laminar inversa

Escudero Barros, Felipe Andrés January 2014 (has links)
Autor no autoriza el acceso a texto completo de su documento hasta el 01/12/2019. / Magíster en Ciencias de la Ingeniería, Mención Mecánica / Ingeniero Civil Mecánico / El objetivo principal del presente estudio es analizar de manera cuantitativa los efectos del índice de oxígeno (OI) en una llama de difusión laminar inversa de etileno, en términos de la producción de hollín, su temperatura, la radiación emitida por la llama y su altura. El OI se define como la fracción molar de oxígeno en el flujo de oxidante y fue variado desde 17% hasta 37%. Para el estudio se escogió un flujo de combustible constante de 2.7 slpm y de aire de 2.2 slpm donde los cambios en el OI se consiguieron dopando aire del laboratorio con oxígeno para OI>21% y con nitrógeno para OI<21%. La altura de la llama se midió mediante la emisión espontánea de radicales CH* y se encontró que la altura de la zona de reacción disminuye a medida que el OI aumenta, a diferencia de la altura de la zona luminosa que aumenta debido a que el hollín continúa formándose más allá de la zona de reacción. Los perfiles radiales de fracción en volumen y temperatura de hollín fueron calculados en base a la metodología de Absorción y Emisión Modulada (MAE) a través de un posterior proceso de deconvolución y regularización. A medida que el OI se incrementa, la fracción en volumen de hollín aumenta debido a que los procesos de formación del hollín se ven favorecidos y continúan por sobre la altura de la zona de reacción de la llama, dadas las condiciones de temperatura. Sin embargo los procesos de oxidación no parecen verse afectados de manera apreciable para las condiciones estudiadas. Por lo anterior se producen mayores cantidades locales de hollín, alcanzando 3.5 ppm para OI de 37%, y también globales, cuantificadas a través de la fracción en volumen integrada con valores máximos de 3 (x 10^{-10} m^2). Por lo mismo, debido a que la cantidad de hollín y la transferencia de calor por radiación están relacionadas, la potencia radiativa de la llama se ve aumentada a medida que crece el OI. Comparando llamas normales e inversas de geometría y energía emitida similar, se puede observar que la cantidad total de hollín generada en una llama inversa es menor que en llamas normales, acentuándose la diferencia en condiciones cercanas a las ambientales. Además, el calor liberado por radiación es menor en llamas inversas para condiciones de OI bajo. Por último, la influencia del OI sobre la altura de la zona de reacción de la llama es mucho mayor en llamas normales, donde la disminución fue de un 50% comparado con un 10% en llamas inversas.
2

Determinación del perfil proteico y presencia de anticuerpos en el plasma seminal de llama (Lama glama) /

Lópes, Francisco Flores. January 2002 (has links)
Tesis de grado para obtener el titulo profesional de "Ingeniero Zootecnista" Universidad Catolocia Boliviana "San Pabo" Unidad Academica Campesina Tiahuanaco. / Abstract in Spanish and English.
3

Texas camelid health and management survey

Jacklitsch, Brenda Louise 02 June 2009 (has links)
A web-based and mail-out survey instrument was created to gather information on camelids in Texas. Information on management, nutrition, diseases, and reproductive problems was collected. The objectives of this research study were: (1) to establish prevalence of various diseases in alpaca and llama populations in Texas; (2) to evaluate association between potential management/nutrition risk factors and specific diseases/reproductive problems; (3) to determine how many camelids are kept in Texas and what their use is; (4) to determine possible disease clustering through spatial analysis. The survey results included 2,079 camelids on 125 farms within Texas. The top five camelid diseases in this sample were intestinal parasites, incisor overgrowth, mites, heat stress, and colic. Univariate analysis and multivariable modeling found associations between potential risk factors and these diseases.
4

Texas camelid health and management survey

Jacklitsch, Brenda Louise 02 June 2009 (has links)
A web-based and mail-out survey instrument was created to gather information on camelids in Texas. Information on management, nutrition, diseases, and reproductive problems was collected. The objectives of this research study were: (1) to establish prevalence of various diseases in alpaca and llama populations in Texas; (2) to evaluate association between potential management/nutrition risk factors and specific diseases/reproductive problems; (3) to determine how many camelids are kept in Texas and what their use is; (4) to determine possible disease clustering through spatial analysis. The survey results included 2,079 camelids on 125 farms within Texas. The top five camelid diseases in this sample were intestinal parasites, incisor overgrowth, mites, heat stress, and colic. Univariate analysis and multivariable modeling found associations between potential risk factors and these diseases.
5

Evaluación del manejo tecnológico en la producción de fibra y carne de alpaca y su incidencia en los niveles de ingreso familiar, en la comunidad campesina de Santa Cruz, distrito de Ilabaya – Jorge Basadre – Tacna - 2011

Parihuana Mamani, Rosa Candelaria 17 January 2013 (has links)
La comunidad campesina de Santa Cruz comprensión del distrito de Ilabaya de la Región Tacna, existe una población de 405 alpacas y 515 llamas, entre otras especies de camélidos; sin embargo, no se tiene información sobre cómo es el manejo tecnológico y su influencia en la economía familiar; por esta razón, el presente estudio tiene como propósito analizar el manejo tecnológico en la producción de fibra, carne de alpacas y llamas y su implicancia en los niveles de ingreso de las familias. Para el análisis de la relación existente entre los ingresos y el manejo tecnológico se han utilizado los estadísticos de Chi - Cuadrado de Pearson, con un nivel de significancia de 0,05; que demostró que solo el uso de equipos de dosificación tiene relación con los ingresos. Posteriormente, mediante regresión múltiple y seleccionando subvariables como total de ganado, posesión de equipos de dosificación, número de cursos asistidos, y número de asistencia técnica recibida como variables independientes, demostraron que tienen relación con el nivel de ingresos de la mencionada comunidad campesina; por tanto, su influencia de acuerdo a la prueba de varianza (Anova) arrojó el valor de sig=0.000 < de α= 0.05, mostrando así una influencia significativa sobre el nivel de ingresos de las familias estudiadas.
6

Ovarian follicular synchronization, ovulation and oocyte development in llamas and alpacas

Ratto, Marcelo 25 July 2005
The purpose of the studies reported in this thesis was to increase our understanding of the reproductive physiology of South American camelids. Studies were conducted in llamas and alpacas to investigate methods to electively control ovarian follicular dynamics, to determine the effects of hormone preparations or biological factors derived from seminal plasma on ovulation induction, and to evaluate the establishment of superstimulatory protocols to induce a consistent ovarian follicular response for oocyte collection. The first study was designed to compare the efficacy of treatments intended to induce follicular wave synchronization among llamas, and to determine the effect of these treatments on pregnancy rates after fixed-time natural mating. In the first experiment, lutenizing hormone (LH) and follicular ablation treatments were most effective for inducing follicular wave synchronization, while estradiol plus progesterone (E/P) treatment was intermediate. In the second experiment, llamas were assigned randomly to Control, (E/P), and LH groups. A single, fixed-time natural mating was permitted 10 to 12 days after treatment. The pregnancy rate was higher (P<0.05) for synchronized llamas (LH and E/P groups combined) than for non-synchronized llamas (Control group). The second study was done to compare the effects of hormonal treatments and natural mating on ovulation induction, interval to ovulation, and luteal development in llamas. No differences were detected among groups (mated, LH, and GnRH) in ovulation rate (80%, 91%, 80%, respectively; P = 0.6), or interval from treatment to ovulation (30.0 ¡À 0.5, 29.3 ¡À 0.6, 29.3 ¡À 0.7 h, respectively; P = 0.9). Similarly, no differences were detected among groups (mated, LH, and GnRH) in maximum corpus luteum (CL) diameter. The third study documents the existence of an ovulation-inducing factor (OIF) in the seminal plasma of alpacas and llamas. In Experiment 1, female alpacas were given alpaca seminal plasma or saline intramuscularly (im) or by intrauterine infusion. Only alpacas that were given seminal plasma im ovulated. In Experiment 2, ovulation was detected in 9/10 (90%) llamas at a mean of 29.3 ¡À 0.7 hours after seminal plasma treatment. In Experiment 3, female llamas were given llama seminal plasma, GnRH, or saline im, and ovulation was detected in 6/6, 5/6, and 0/6 llamas, respectively (P < 0.001). Treatment was followed by a surge (P < 0.01) in plasma LH concentration beginning 15 minutes and 75 minutes after treatment with GnRH and seminal plasma, respectively. Plasma LH remained elevated longer in the seminal plasma group (P < 0.05), and plasma progesterone concentration was twice as high in the seminal plasma group (P < 0.01). The fourth study describes the presence of an OIF in the seminal plasma of Bos taurus ¨C a species conventionally considered to ovulate spontaneously - contains OIF. Bull seminal plasma induced ovulations in 26% (5/19) of llamas compared to 0% (0/19) in PBS group (P < 0.001). The ovulation rate was lower (P < 0.01) in bull seminal plasma group compared to that in the groups treated with alpaca or llama seminal plasma (100%). The fifth study was conducted to determine a local versus systemic effect of ovulation-inducing factor in seminal plasma. Ovulation rate in the seminal plasma intramuscular group (93%) was higher (P < 0.01) than seminal plasma intrauterine group (41%), while the seminal plasma intrauterine curettage group was intermediate (67%). The sixth study was done to determine the time required for llama oocyte to reach the maturation stage, and to establish a superstimulatory treatment for oocyte collection. Llama oocytes reached second metaphase as early as 28 h after in vitro culture. The FSH- and eCG-treated groups did not differ (P = 0.85) with respect to the number of follicles ¡Ý6 mm at the time of cumulus-oocyte complex (COC) collection (17.9 ¡À 2.2 vs 17.7 ¡À 2.2), the number of COC collected (10.7 ¡À 2.1 vs 11.2 ¡À 2.3 per llama), or the collection rate per follicle aspirated (71 vs 74%). Finally, in the last study, the effect of two superstimulatory treatments was evaluated on ovarian response and COC collection efficiency and oocyte maturation in alpacas. No difference (P = 0.54) was observed between FSH and eCG- treated alpacas in the number of expanded (11.5 ¡À 2.9 vs 8.8 ¡À 2.8) or compact COC collected with ¡Ý3 layers of cumulus cells (12.5 ¡À 4.3 vs 14.3 ¡À 2.6; P = 0.72). No difference (P = 0.1) was detected between FSH and eCG groups in the number of expanded COC at first metaphase (1.2 ¡À 1.2 vs 1.7 ¡À 0.6) or second metaphase stage (8.5 ¡À 1.9 vs 6.0 ¡À 2.1) respectively. In conclusion, these studies demonstrated that the control of ovarian follicular wave emergence and ovulation induction in llamas will contribute consistently to the establishment of fixed-time natural or artificial insemination as well as recipient synchronization in embryo transfer programs. The discovery of an ovulatory molecule in the semen of this species generates a new area of research regarding the ovulation mechanism in induced ovulators. Characterization of this factor may have important implications in the diagnosis and treatment of male and female infertility. Finally, the superstimulatory treatments and oocyte development studies will establish the baseline for the development of an in vitro embryo production system in llamas and alpacas.
7

Ovarian follicular synchronization, ovulation and oocyte development in llamas and alpacas

Ratto, Marcelo 25 July 2005 (has links)
The purpose of the studies reported in this thesis was to increase our understanding of the reproductive physiology of South American camelids. Studies were conducted in llamas and alpacas to investigate methods to electively control ovarian follicular dynamics, to determine the effects of hormone preparations or biological factors derived from seminal plasma on ovulation induction, and to evaluate the establishment of superstimulatory protocols to induce a consistent ovarian follicular response for oocyte collection. The first study was designed to compare the efficacy of treatments intended to induce follicular wave synchronization among llamas, and to determine the effect of these treatments on pregnancy rates after fixed-time natural mating. In the first experiment, lutenizing hormone (LH) and follicular ablation treatments were most effective for inducing follicular wave synchronization, while estradiol plus progesterone (E/P) treatment was intermediate. In the second experiment, llamas were assigned randomly to Control, (E/P), and LH groups. A single, fixed-time natural mating was permitted 10 to 12 days after treatment. The pregnancy rate was higher (P<0.05) for synchronized llamas (LH and E/P groups combined) than for non-synchronized llamas (Control group). The second study was done to compare the effects of hormonal treatments and natural mating on ovulation induction, interval to ovulation, and luteal development in llamas. No differences were detected among groups (mated, LH, and GnRH) in ovulation rate (80%, 91%, 80%, respectively; P = 0.6), or interval from treatment to ovulation (30.0 ¡À 0.5, 29.3 ¡À 0.6, 29.3 ¡À 0.7 h, respectively; P = 0.9). Similarly, no differences were detected among groups (mated, LH, and GnRH) in maximum corpus luteum (CL) diameter. The third study documents the existence of an ovulation-inducing factor (OIF) in the seminal plasma of alpacas and llamas. In Experiment 1, female alpacas were given alpaca seminal plasma or saline intramuscularly (im) or by intrauterine infusion. Only alpacas that were given seminal plasma im ovulated. In Experiment 2, ovulation was detected in 9/10 (90%) llamas at a mean of 29.3 ¡À 0.7 hours after seminal plasma treatment. In Experiment 3, female llamas were given llama seminal plasma, GnRH, or saline im, and ovulation was detected in 6/6, 5/6, and 0/6 llamas, respectively (P < 0.001). Treatment was followed by a surge (P < 0.01) in plasma LH concentration beginning 15 minutes and 75 minutes after treatment with GnRH and seminal plasma, respectively. Plasma LH remained elevated longer in the seminal plasma group (P < 0.05), and plasma progesterone concentration was twice as high in the seminal plasma group (P < 0.01). The fourth study describes the presence of an OIF in the seminal plasma of Bos taurus ¨C a species conventionally considered to ovulate spontaneously - contains OIF. Bull seminal plasma induced ovulations in 26% (5/19) of llamas compared to 0% (0/19) in PBS group (P < 0.001). The ovulation rate was lower (P < 0.01) in bull seminal plasma group compared to that in the groups treated with alpaca or llama seminal plasma (100%). The fifth study was conducted to determine a local versus systemic effect of ovulation-inducing factor in seminal plasma. Ovulation rate in the seminal plasma intramuscular group (93%) was higher (P < 0.01) than seminal plasma intrauterine group (41%), while the seminal plasma intrauterine curettage group was intermediate (67%). The sixth study was done to determine the time required for llama oocyte to reach the maturation stage, and to establish a superstimulatory treatment for oocyte collection. Llama oocytes reached second metaphase as early as 28 h after in vitro culture. The FSH- and eCG-treated groups did not differ (P = 0.85) with respect to the number of follicles ¡Ý6 mm at the time of cumulus-oocyte complex (COC) collection (17.9 ¡À 2.2 vs 17.7 ¡À 2.2), the number of COC collected (10.7 ¡À 2.1 vs 11.2 ¡À 2.3 per llama), or the collection rate per follicle aspirated (71 vs 74%). Finally, in the last study, the effect of two superstimulatory treatments was evaluated on ovarian response and COC collection efficiency and oocyte maturation in alpacas. No difference (P = 0.54) was observed between FSH and eCG- treated alpacas in the number of expanded (11.5 ¡À 2.9 vs 8.8 ¡À 2.8) or compact COC collected with ¡Ý3 layers of cumulus cells (12.5 ¡À 4.3 vs 14.3 ¡À 2.6; P = 0.72). No difference (P = 0.1) was detected between FSH and eCG groups in the number of expanded COC at first metaphase (1.2 ¡À 1.2 vs 1.7 ¡À 0.6) or second metaphase stage (8.5 ¡À 1.9 vs 6.0 ¡À 2.1) respectively. In conclusion, these studies demonstrated that the control of ovarian follicular wave emergence and ovulation induction in llamas will contribute consistently to the establishment of fixed-time natural or artificial insemination as well as recipient synchronization in embryo transfer programs. The discovery of an ovulatory molecule in the semen of this species generates a new area of research regarding the ovulation mechanism in induced ovulators. Characterization of this factor may have important implications in the diagnosis and treatment of male and female infertility. Finally, the superstimulatory treatments and oocyte development studies will establish the baseline for the development of an in vitro embryo production system in llamas and alpacas.
8

Evaluación de la Carga Parasitaria y su Interacción Madre-Cría, Desde el Nacimiento al Destete, en Alpacas (Vicugna pacos) y Llamas (Lama glama) en Cicas La Raya, Cusco

Mamani Fernández, Julio Erick 14 October 2013 (has links)
Se evaluó la carga parasitaria y su interacción madre-cría, desde el nacimiento al destete en alpacas (Vicugna pacos) y llamas (Lama glama), en el Centro Investigaciones de Camélidos Sudamericanos CICAS “La Raya”, Cusco. Durante los meses de febrero a setiembre, se utilizaron 15 alpacas madres con sus respectivas crías al igual que en llamas con sus crías, en una ecología de alrededor de 4 000 m.s.n.m. y que no recibieron tratamiento antihelmíntico durante el lapso de estudio, el monitoreo fue desde el nacimiento, cada semana hasta el día del destete. Mediante la técnica de Mc master modificado utilizando una solución de flotación de nitrato de sodio. Se identificó a las siguientes especies de parásitos: Eimera lamae, E. alpacae, E. punoensis, E. macusaniensis y E. ivitaensis, además de los nematodos como Nematodirus spathiger, N. Lamae, Lamanema chavezi, Trichuris ssp, Capillaria ssp y huevos tipo Strongylus en crías y madres de alpaca y llama. Las mayores cargas parasitaria son: Eimeria ssp con 879, 11 716 y 3593 OPG en llama madre y cría y alpaca cría respectivamente, Nematodirus ssp con 21 HPG y 23 HPG en alpacas madre y cría respectivamente, Lamanema chavezi con 26 HPG en llamas madre, HTS con 24 HPG tanto alpaca y llama madre, además hay un significativo efecto de la carga parasitaria de la madre hacia su cría con valor desde 90,15% al 100% de relación en las principales especies parasitarias como son: Eimeria ssp, Nematodirus ssp, Lamanema chavezi y HTS en alpacas y llamas y un efecto menor en Trichuris ssp para alpacas. No se estableció la correlación entre los parásitos de madre y parásitos de su cría.
9

Hair, Feces and Breath Isotope Fractionation in Alpacas (Llama pacos), Llamas (Llama glama) and Guanacos (Llama guanacoe) from Bolivia and Chile

Lopez Lopez, Lino Constancio 21 November 2008 (has links) (PDF)
This study was conducted to determinate carbon and nitrogen isotope fractionation in Bolivian and Chilean alpaca, llama and guanaco, hair, breath, plasma and feces. We also wanted to determine forage selection for these camelids using stable isotope technology. From the data, niche feeding and diet selection habits will determinate based on fecal composition. Bolivian sites were located near the high snow Altiplano Mountains at Tomarapi, Sajama, and at the Technical University Oruro's research center at Condoriri, Bolivia. Chilean samples were collected at INIA's (Instituto Nacional de Investigacion Agropecuaria) Kampenaike Research Station, Punta Arenas, Chile. Bolivian alpacas and llamas were 3 to 5 years of age from producer herds and the Oruro University's camelid herd. Chilean animals were selected from INIA- Kampenaike's camelid herd. The alpacas, llamas and guanacos were selected based on heath status: no conformation defects, illness, genetic abnormalities or apparent nutrition problems. Samples were taken of fiber, feces, and blood from alpacas, llamas, and guanacos. Forage samples from pastures and grazing areas were taken. Forage species that were collected came from the asteraceae, berberidaceae, gramineae, caryophyllaceae, leguminoseae, plantaginaceae, gentianiaceae and the chenopodaceae families and ranged from -15.5‰ to -33.9‰ δ13C and -3.0‰ to 6.4‰ δ15N. Isotope values for feces and fiber were similar for the two Bolivian sites, but the Chilean values were significantly more depleted. This was attributed to the forage isotopic values being significantly more depleted than those found in Bolivia. Forage selection, based on fecal and forage isotopic signatures supported the observation that alpacas, llamas and guanacos eat different forages. This is dependent on forage source and time of year (dry versus wet season). Stable isotope technology will be a useful tool in determining forage selection and species competition or interactions in South American Camelids.
10

Empathetic AI for Enhanced Workplace Engagement / Empatisk AI för ökat arbetsplatsengagemang

Jusic, Samuel, Klockars, Love, Melinder, Anthony, Uddin, Anik, Wadman, Isak, Zanetti, Marcus January 2024 (has links)
This report outlines the research focused on finding the system design for Happymaker AI, a large language model with a mission to promote well-being at workplaces through daily interactions. The study includes a market analysis of relevant system components, such as database, cloud storage, cloud computing service and large language model, as well as the development of a prototype. Despite facing challenges including limited training data and resource constraints, the prototype was developed using the Llama 2 13B model which was quantized to 8-bits and fine-tuned using LoRA. Through research and prototyping of Happymaker AI, recommendations for the system design were established. These findings provide a foundation for the further development of an ethical AI system, specifically tailored for user data security and scalability. The findings also introduce a new perspective on empathy and personal well-being within the AI field, emphasizing the importance of integrating human-centric values into technological advancements. / Denna rapport skildrar forskningen som fokuserade på att hitta systemdesignen för Happymaker AI, en stor språkmodell med uppdraget att främja välmående på arbetsplatser genom dagliga interaktioner. Studien inkluderar en marknadsanalys av relevanta systemkomponenter såsom databas, molnlagring, molntjänster och en stor språkmodell, samt utvecklingen av en prototyp. Trots utmaningar, inklusive begränsad träningsdata och resursbegränsningar utvecklades prototypen med modellen Llama 2 13B som kvantiserades till 8-bit och tränades med LoRA. Genom forskning och prototypframtagning av Happymaker AI fastställdes rekommendationer för systemdesignen. Resultaten av studien ger en grund för vidareutveckling av ett etiskt AI-system som är anpassat för användardatasäkerhet och skalbarhet. Samtidigt introduceras ett nytt perspektiv på empati och personligt välmående inom AI-fältet, vilket betonar vikten av att integrera människocentrerade värderingar i teknologiska framsteg.

Page generated in 0.0453 seconds