42 results on '"Jefferson TA"'
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2. Solución al problema de despacho hidrotérmico a corto plazo mediante la programación no lineal aplicada a sistemas de uno y varios nodos
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Josue Ortiz, Jefferson Tayupanda, and Carlos Quinatoa
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Despacho Económico ,Optimización ,hidrotérmico ,corto plazo ,Technology (General) ,T1-995 - Abstract
La presente investigación propone dos modelos al problema de despacho económico a corto plazo de los sistemas eléctricos de potencia por medio de la programación no lineal (PNL). Los problemas planteados serán resueltos mediante la función de costo del despacho económico clásico en donde se considerarán centrales de generación térmica e hidráulicas para obtención de la potencia eléctrica generada en cada uno de los nodos, la metodología propuesta será utilizada para un periodo a corto plazo de 24 horas con diferente demanda horaria, en primera instancia se desarrollará el modelo para un solo nodo con embalses en cascada, mientras que el segundo caso será desarrollado en el sistema de 14 buses de la IEEE, se realizan breves modificaciones al modelo original con el fin de incluir las unidades de generación hidráulica. La programación no lineal muestra resultados satisfactorios cumpliendo con las restricciones operativas implementadas en el modelo matemático, además se tienen reducciones de la generación térmica lo que significa menor costo, el primer modelo es validado mediante bibliografía obteniendo un costo de operación de $904.990 mientras que en el segundo modelo se obtiene un costo de total de $129.800.
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- 2024
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3. Aspectos da cultura Kyikatêjê em uma experiência de ensino de Matemática
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Jefferson Tassio Fonseca Santos and João Pedro Antunes de Paulo
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Kyikatêjê ,modelo dos campos semánticos ,escola indígena ,estágio ,Philosophy (General) ,B1-5802 ,Science ,Social sciences (General) ,H1-99 - Abstract
Neste trabalho apresentamos uma experiência de estágio realizada em uma escola indígena Kyikatêjê, na região norte do Brasil e analisamos aspectos dessa experiência a partir dos conceitos de autoridade e espaço comunicativo transcultural. Para tanto, descrevemos de modo breve o contexto no qual a pesquisa de estágio ocorreu, destacando os objetivos do estágio, o período de realização e os professores envolvidos. Nesse relato, situamos o ponto de interesse que motivou a escrita do presente trabalho. Indicado nosso objeto de estudos, apresentamos duas seções teóricas que caracterizam a perspectiva com a qual trabalhamos. Na primeira, expomos o conceito de autoridade, entendida a partir do Modelo dos Campos Semânticos. Apresentamos como esse conceito está relacionado à justificação utilizada na produção de conhecimento. Ao fazer isso, afirmamos que nosso interesse se dirige aos aspectos epistemológicos da experiência realizada. Na sessão seguinte, apresentamos o conceito de espaço comunicativo transcultural, como sendo aquelas situações de interação onde duas ou mais culturas se encontram e que a alteridade do espaço constituído nesse encontro, possibilita o compartilhamento de legitimidades entre elas. Após apresentar os conceitos teóricos é apresentada a experiência de estágio de modo a colocar em evidência a relação entre o estagiário, os professores e os alunos e não os conteúdos trabalhos. Na última seção essa experiência de estágio é analisada à luz dos conceitos apresentados. Apontamos na conclusão que o comportamento dos alunos advém de legitimidades constituídas na cultura da qual fazem parte, mas esse comportamento não indica necessariamente uma abertura para o processo de aprendizagem. Apontamos, também, que a criação de um espaço comunicativo que mobiliza as legitimidades da cultura Kyikatêjê na aula de Matemática, privilegiando os modos de produzir conhecimento dessa cultura, oportunizou uma mudança no processo de produção de conhecimento dos alunos.
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- 2023
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4. Intrathecal morphine is associated with reduction in postoperative opioid requirements and improvement in postoperative analgesia in patients undergoing open liver resection
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Jefferson Tang, Leonid Churilov, Chong Oon Tan, Raymond Hu, Brett Pearce, Luka Cosic, Christopher Christophi, and Laurence Weinberg
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Analgesia ,Liver resection ,Hospital costs ,Intrathecal morphine ,Enhanced recovery after surgery ,Anesthesiology ,RD78.3-87.3 - Abstract
Abstract Background Our study aimed to test the hypothesis that the addition of intrathecal morphine (ITM) results in reduced postoperative opioid use and enhanced postoperative analgesia in patients undergoing open liver resection using a standardized enhanced recovery after surgery (ERAS) protocol with multimodal analgesia. Methods A retrospective analysis of 216 adult patients undergoing open liver resection between June 2010 and July 2017 at a university teaching hospital was conducted. The primary outcome was the cumulative oral morphine equivalent daily dose (oMEDD) on postoperative day (POD) 1. Secondary outcomes included postoperative pain scores, opioid related complications, and length of hospital stay. We also performed a cost analysis evaluating the economic benefits of ITM. Results One hundred twenty-five patients received ITM (ITM group) and 91 patients received usual care (UC group). Patient characteristics were similar between the groups. The primary outcome - cumulative oMEDD on POD1 - was significantly reduced in the ITM group. Postoperative pain scores up to 24 h post-surgery were significantly reduced in the ITM group. There was no statistically significant difference in complications or hospital stay between the two study groups. Total hospital costs were significantly higher in the ITM group. Conclusion In patients undergoing open liver resection, ITM in addition to conventional multimodal analgesic strategies reduced postoperative opioid requirements and improved analgesia for 24 h after surgery, without any statistically significant differences in opioid-related complications, and length of hospital stay. Hospital costs were significantly higher in patients receiving ITM, reflective of a longer mandatory stay in intensive care. Trial registration Registered with the Australian New Zealand Clinical Trials Registry (ANZCTR) under ACTRN12620000001998 .
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- 2020
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5. Impacts of fisheries on the Critically Endangered humpback dolphin Sousa chinensis population in the eastern Taiwan Strait
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Slooten, E, primary, Wang, JY, additional, Dungan, SZ, additional, Forney, KA, additional, Hung, SK, additional, Jefferson, TA, additional, Riehl, KN, additional, Rojas-Bracho, L, additional, Ross, PS, additional, Wee, A, additional, Winkler, R, additional, Yang, SC, additional, and Chen, CA, additional
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- 2013
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6. Reativação Tectônica Quaternária no Domínio Sul da Província Borborema, NE do Brasil: Integração de Dados Morfométricos, Geológicos e Geofísicos da Bacia do Rio Una
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Osvaldo José Correia Filho, José Antonio Barbosa, Bruno Tavares, Hewerton Alves da Silva, Kleython de Araujo Monteiro, Carlos Eduardo Guedes Fabin, Jefferson Tavares Cruz Oliveira, Felipe Ribeiro Santana, and Sidney Marinho da Silva
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neotectônica ,índice morfométrico ,província borborema ,Physical geography ,GB3-5030 ,Geography (General) ,G1-922 - Abstract
Integração de dados em diferentes escalas foi realizada com o objetivo de identificar possíveis efeitos de reativações tectônicas cenozoicas (pós-rifte), relacionadas ao embasamento adjacente à Bacia Pernambuco, sobre o qual está localizada a bacia hidrográfica do Rio Una. O estudo foi baseado na integração de parâmetros morfométricos do canal do Rio Una, modelados a partir de imagens de radar, dados de geologia de superfície e dados de sísmica de reflexão multicanal 2D adquiridos no canal do rio, próximo às cidades de Barreiros e Palmares. A análise morfométrica se baseou no cálculo da relação declividade vs. extensão (RDE) ao longo do perfil longitudinal do Rio Una. Dados geológicos foram coletados em afloramentos no embasamento próximo aos municípios de Barreiros e Palmares. Também foram investigados os depósitos da Formação Barreiras na região costeira, próximo ao município de São José da Coroa Grande. A análise do perfil longitudinal mostrou que o Rio Una está implantado sobre três superfícies criadas por eventos sucessivos de soerguimento e erosão, as quais controlaram a compartimentação de sua bacia hidrográfica. O estudo do índice RDE mostrou a ocorrência de anomalias de primeira ordem, no médio curso, e de segunda ordem, no médio e baixo curso do rio. As anomalias de primeira e segunda ordem estão localizadas sobre as principais zonas de cisalhamento pré-cambrianas que cortam o embasamento com orientação NE-SW. As anomalias também estão relacionadas a falhas e fraturas mais jovens com direção NW-SE. A interpretação dos dados sísmicos mostrou um arranjo de falhas e fraturas de alto ângulo no embasamento que afetaram depósitos sedimentares de idade quaternária e holocênica. Também foram observadas falhas em depósitos da Formação Barreiras (Mioceno) depositados sobre o embasamento próximo a borda da Bacia Pernambuco. A geometria dos planos de falha é indicativa de estruturas do tipo flor, relacionadas a um regime de reativação transcorrente que está atuando sobre a margem continental, com compressão máxima E-W e extensão N-S. Este regime afetou a morfologia do canal do Rio Una, bem como os depósitos sedimentares associados à sua bacia de drenagem.
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- 2020
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7. Variação da pressão intraocular no exercício supino realizado em diferentes posições
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Fabrício Teixeira Garramona, Lucas Ruiz Storti, Alex Sander Soares, Sidney Diyoo Tamura, Sérgio Paulo de Tarso Domingues, Jefferson Tavares Paschoini, and Marcel Conte
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pressão intraocular/fisiologia ,exercício ,treinamento de resistência ,postura ,Sports medicine ,RC1200-1245 - Abstract
O objetivo do estudo foi verificar a variação da pressão intraocular (PIO) no exercício de supino realizado nas posições reto, inclinado e declinado. Foram avaliados oito indivíduos saudáveis, submetidos a três sessões do exercício resistido de supino, com volume e intensidade de 3 séries de 15 repetições com 60% 1RM, intervalo de 60 segundos entre as séries e velocidade moderada, de acordo com as seguintes posições: P1) Supino executado na posição reta (0º); P2) Supino executado na posição inclinada (45º) e P3) Supino executado na posição declinada (-30º). As mensurações da PIO foram realizadas utilizando o Tonômetro de Perkins em três momentos distintos, sendo: M1) imediatamente antes do exercício; M2) imediatamente após a terceira série e M3) três minutos após a finalização da terceira série. A análise estatística foi realizada pelo Teste de normalidade de Shapiro-Wilk, e utilizado ANOVA com pós-teste de Bonferroni adotando-se um nível de significância 5%. O software utilizado foi o GraphPad Prism®. Os resultados demonstraram o efeito hipotensor do exercício físico na PIO, foi observada uma redução significativa da PIO após o exercício no supino independentemente da posição corporal adotada, tendo apresentando uma redução média após a realização do exercício de aproximadamente 3 a 4 mmHg ou 25%. Concluímos então que mesmo em posição potencialmente hipertensiva, o exercício promoveu redução significativa da PIO. Pode-se atribuir a queda da PIO decorrente do exercício resistido, a mecanismos relacionados a diminuição da produção do humor aquoso em contrapartida ao aumento do escoamento desse líquido pelo ângulo camerular.
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- 2019
8. Evaluation of pregnancy rates of Bos indicus cows subjected to different synchronization ovulation protocols using injectable progesterone or an intravaginal device
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Jefferson Tadeu Campos, Fábio Morotti, Camila Bortoliero Costa, Larissa Zamparone Bergamo, and Marcelo Marcondes Seneda
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IATF ,Nelore ,Progesterona injetável ,Taxa de prenhez. ,Agriculture (General) ,S1-972 - Abstract
This study evaluated the pregnancy rate in Nelore cows (Bos indicus) that were subjected to fixed-time artificial insemination (FTAI) using different protocols consisting of injectable progesterone (P4) or an intravaginal device (impregnated with P4). Multiparous cows 72-84 months in age, 30-45 days postpartum, were selected on the basis of the absence of a corpus luteum (CL) and follicles < 8 mm after transrectal palpation and ultrasound examinations. On a random day of the estrus cycle (D0), the selected animals (n = 135) were randomly assigned to one of three experimental groups (n = 45 each). Group I (injectable P4/FTAI 36 hours) received 250 mg of injectable P4 and 2 mg EB on D0; on D7, they received 500 µg of cloprostenol; on D8, 300 IU of eCG and 1 mg of EB were administered; and finally, FTAI was performed 36 hours after the application of EB. Group II (injectable P4/FTAI 48 hours) received the same protocol as Group I, except that the FTAI was performed 48 hours after ovulation induction. The animals of Group III (Control/CIDR) received a conventional protocol for FTAI using an intravaginal device (D0: P4 and 2 mg EB; D8: device removal, 500 µg cloprostenol, 300 IU eCG, 1 mg EB; and FTAI performed 48 hours after removal of the device). The results showed that cows synchronized with the conventional protocol for FTAI (Control/CIDR) had a higher pregnancy rate (60 %, 27/45) than those synchronized with an injectable P4/FTAI 36 hours (33.33 %; 15/45, P = 0.010). However, the group receiving injectable P4 group/FTAI 48 hours had a similar pregnancy rate (48.9 %; 22/45; P = 0.290) when compared to both the group receiving the conventional protocol and that receiving injectable P4/FTAI 36 hours (P = 0.134). Although the injectable P4 may affect pregnancy rate with the FTAI performed in 36 hours, we found similar pregnancy rates from cows inseminated 48 hours after induction ovulation, considering injectable or intravaginal P4. Therefore, we suggest that injectable P4 represents an alternative source of progesterone for synchronization of cattle for FTAI.
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- 2016
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9. Pregnancy rate evaluation in lactating and non-lactating Nelore cows subjected to fixed-time artificial insemination using injectable progesterone
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Jefferson Tadeu Campos, Fábio Morotti, Larissa Zamparone Bergamo, Camila Bortoliero Costa, and Marcelo Marcondes Seneda
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Progesterona Injetável ,Vaca lactante ,Vaca não lactante ,Sincronização da ovulação ,Taxa de prenhez. ,Agriculture (General) ,S1-972 - Abstract
Most fixed-time artificial insemination (FTAI) protocols utilize progesterone (P4) as a hormonal source to achieve synchronization of estrus in cattle. The use of an injectable P4 source to control estrus would be an interesting pharmacological strategy owing to the practicality of parenteral application. However, the effects of injectable P4 on estrus cycle control in cattle remain poorly studied. In particular, no existing studies have investigated the effect of injectable P4 on the fertility of cows subjected to FTAI. The aim of this study was to evaluate the pregnancy rate of lactating and non-lactating Nelore cows subjected to FTAI with injectable P4. Of the 422 non-lactating cows in this study, 162 (38.3%) became pregnant by 60 days post-FTAI. In the lactating group (n = 516), 166 (32.1%) were pregnant by 60 days after treatment with injectable P4. The proportions of lactating and non-lactating cows becoming pregnant were compared using the chi-square test, adopting a significance level of P < 0.05. It was found that the pregnancy rate of the cows subjected to FTAI with injectable P4 was influenced by lactation status. Lactating cows had lower reproductive performance, possibly because of their higher nutritional requirements. However, the use of injectable P4 shows promising results and may prove to be a useful strategy in large-scale livestock production.
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- 2016
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10. Fixed-time artificial insemination using injectable progesterone: ovarian follicular dynamics and pregnancy rates of Nelore cows (Bos indicus) with and without a corpus luteum
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Fábio Morotti, Jefferson Tadeu Campos, and Marcelo Marcondes Seneda
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Bos indicus ,Ultrasonography ,Follicular growth ,Ovulation and dominant follicle ,Agriculture (General) ,S1-972 - Abstract
This study evaluated the follicular dynamics and the pregnancy rates of Nelore cows with or without a CL synchronized with FTAI employing injectable progesterone (P4). Multiparous cows (n=44), 45-65 days postpartum were allocated into a 2x2 factorial. Eleven cows with and 11 without a CL received a conventional protocol of FTAI (D0/1 g P4 + 2 mg EB; D8/500 ?g cloprostenol, 300 IU eCG and 24 h later 1 mg EB; D10/FTAI). Other 11 cows with and 11 without a CL received 350 mg of injectable P4 (300 mg sc and 50 mg im) and 2 mg of EB im on D0. On D6, 500 ?g of cloprostenol and 300 IU of eCG were administered im. After 24 h, 1 mg of EB was administered im and FTAI was performed on D8. The results were analyzed by ANOVA and Tukey or by Chi-square test (p?0.05). The presence of follicles ? 5mm on D4, follicular growth rate and CL diameter were similar between groups (50-55%, 1.1-1.2mm/ day and 16.1-17.6mm; respectively). The diameter of the dominant follicle (DF) at FTAI and ovulatory follicle (OF) were similar between groups with CL (10.5±1.8 and 11.4±1.3mm, respectively) and without CL (10.8±2.3 and 11.1±2.2mm, respectively) but device was higher than injectable (11.7±2.0 and 11.8±1.7 vs. 9.7±1.7 and 10.6±2.0mm, respectively). The ovulation and pregnancy rate were similar between groups with CL (59% and 36%, respectively) and without CL (77% and 27%, respectively) but device was higher than injectable (91% and 45% vs. 45.5% and 18%; respectively). The ciclicity did not affect the follicular dynamics and pregnancy rate. The device showed higher diameter of the DF at FTAI, OF and ovulation and pregnancy rates. However, the injectable P4 produced similar percentages of follicles ? 5 mm on D4, follicular growth rate and CL diameter, raising the possibility of further investigation.
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- 2014
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11. Ovarian follicular dynamics of Nelore (Bos indicus) cows subjected to a fixed-time artificial insemination protocol with injectable progesterone
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Fábio Morotti, Jefferson Tadeu Campos, Eduardo Raele Oliveira, and Marcelo Marcondes Seneda
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Bos indicus ,Ultrasonography ,Follicular growth ,Ovulation ,Dominant follicle ,Agriculture (General) ,S1-972 - Abstract
This study aims to evaluate ovarian follicular dynamics of Nelore cows subjected to fixed-time artificial insemination (FTAI) with injectable progesterone (P4) or intravaginal device. In the device group, 20 cows received an intravaginal device with 1 g P4 and administration of 2 mg estradiol benzoate (EB) intramuscularly (im) on D0. The device was removed on D8, followed by administration of 500 ?g cloprostenol, 300 IU equine chorionic gonadotropin (eCG) and 1 mg estradiol cypionate (EC), im. The cows were inseminated 48h later. In the injectable group, 350 mg P4 (300 mg subcutaneously and 50 mg im) and 2 mg EB im were administered on D0 to 16 cows. On D6, 500 ?g cloprostenol, 300 IU eCG and 1 mg EC were administered im. The FTAI was performed 48h later. Sixty-five percent of cows from the device group (13/20) and 75% from the injectable group (12/16) showed follicles ? 5 mm on D4 (p>0.05). The average rate of follicular growth was 0.92±0.25 mm/day for the device group and 1.06±0.45 mm/day for the injectable group (p>0.05). The average diameter of the dominant follicle (DF) at FTAI was 11.4±1.4 mm for the device group and 10.8±1.8 mm for the injectable group (p>0.05). In the device group, ovulatory follicles (OF) had an average diameter of 12.1±1.4 mm, and in the injectable group 12.3±1.6 mm (p>0.05). Ninety percent of the device group (18/20) and 37.5% of the injectable group (6/16) demonstrated ovulation (p
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- 2014
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12. Porfiria aguda intermitente: relato de caso e revisão da literatura Acute intermittent porphyria: case report and review of the literature
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Daniela von Ah Lopes, Marcelo Araújo do Valle, Jéfferson Taguti, Regina Celli Thomé Castro Taguti, Gustavo Navarro Betônico, and Fabiana Clemente Medeiros
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Porfiria aguda intermitente ,Hiponatremia ,Cirurgia bariátrica ,Porphyria, acute intermittent ,Hyponatremia ,Bariatric surgery ,Medical emergencies. Critical care. Intensive care. First aid ,RC86-88.9 - Abstract
Porfiria aguda intermitente é patologia incomum, com conseqüências potencialmente graves se não reconhecida precocemente. Dentre as possíveis causas de indução de crises de porfiria, a redução da ingestão calórica é descrita na literatura. Relatamos um caso de porfiria aguda intermitente no pós-operatório tardio de gastroplastia indicada para tratamento da obesidade, revisando aspectos do diagnóstico e tratamento da patologia na unidade de terapia intensiva. Paciente feminina, 31 anos, com história de gastroplastia há 3 semanas admitida na unidade de terapia intensiva com rebaixamento do nível de consciência e desconforto respiratório. Evoluiu com agitação psicomotora, confusão mental, dor abdominal e tetraparesia proximal. Na investigação diagnóstica foi encontrado hiponatremia grave (92 mEq/L), hipomagnesemia, hipofosfatemia e hipocalcemia, urina turva, sem hematúria. Aventou-se hipótese de porfiria aguda, realizado dosagem do ácido delta-aminolevulínico e porfobilinogênio na urina de 24h, com elevação de ambos. Iniciado tratamento com dieta rica em carboidratos, sem utilizar hematina ou arginato de heme, devido à dificuldades no fornecimento destas medicações. Evoluiu com melhora clínica gradativa e recuperação completa da força muscular após 8 meses. A porfiria aguda intermitente possui sinais e sintomas comuns a muitas patologias clínicas e neuropsiquiátricas dificultando o diagnóstico, em especial quando estes se manifestam isoladamente. Assim, deve-se incluir a porfiria aguda intermitente no diagnóstico diferencial de distúrbios neurológicos, psiquiátricos e gastroenterológicos em crises, no qual todos os demais exames estejam normais. Atenção deve ser dada a pacientes submetidos à cirurgias, em especial cirurgia bariátrica que, além do estresse cirúrgico, limita substancialmente a ingesta calórica podendo desencadear crises. Não há descrito na literatura, até o momento, nenhum caso de porfiria aguda intermitente no pós-operatório de cirurgia bariátrica.Acute intermittent porphyria is an unusual pathology with potentially severe consequences when not early detected. Among the possible causes of porphyric crises decrease of caloric intake has been described. A case of acute intermittent porphyria in the late postoperative period of a bariatric surgery performed for treatment of obesity is reported. A review of the diagnostic aspects and management of this pathology in the intensive care unit follows. A 31 year old woman was admitted in the intensive care unit three weeks after a bariatric surgery, with decreased level of consciousness and respiratory distress. The patient evolved with psychomotor agitation, mental confusion, abdominal pain and proximal tetraparesis. Diagnosis investigation disclosed severe hyponatremia (92mEq/L), hypomagnesemia, hypophosfatemia and hypocalcemia and cloudy urine without hematuria. Acute porphyria was suspected and the urine test detected high delta amino-levulinic acid and porphobilinogen. Treatment consisted of a correction of electrolyte disturbances and high carbohydrate intake. Hematin and heme arginate were not used, due to the difficulty to acquire the medication. After 8 months the patient progressed with full recovery of muscle strength and a clinical improvement. Acute intermittent porphyria has signs and symptoms common to several clinical, neurological, psychiatric and gastroenterological pathologies, which complicate diagnosis. Therefore, acute intermittent porphyria should be included in the differential diagnosis of neurological, psychiatric and gastroenterological alterations when results of all other exams are normal. Attention must be given to patients undergoing surgery mainly bariatric that, in addition to procedure stress, substantially limit the total caloric intake, potentially triggering crises. Review of literature did not disclose any report of acute intermittent porphyria crisis induced by bariatric surgery.
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- 2008
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13. Metástase em tonsila palatina como uma apresentação de carcinoma pulmonar de pequenas células
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Helena Hotz Arroyo, Jefferson Takehara, Allex Itar Ogawa, Ronaldo Frizzarini, Rui Imamura, and Henrique Moura de Paula
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carcinoma de pequenas células do pulmão ,metástase linfática ,neoplasias tonsilares ,orofaringe ,tonsila palatina ,Otorhinolaryngology ,RF1-547 - Published
- 2013
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14. Revised taxonomy of eastern North Pacific killer whales ( Orcinus orca ): Bigg's and resident ecotypes deserve species status.
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Morin PA, McCarthy ML, Fung CW, Durban JW, Parsons KM, Perrin WF, Taylor BL, Jefferson TA, and Archer FI
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Killer whales ( Orcinus orca ) are currently recognized as a single ecologically and morphologically diverse, globally distributed species. Multiple morphotypes or ecotypes have been described, often associated with feeding specialization, and several studies have suggested taxonomic revision to include multiple subspecies or species in the genus. We review the ecological, morphological and genetic data for the well-studied 'resident' and Bigg's (aka 'transient') ecotypes in the eastern North Pacific and use quantitative taxonomic guidelines and standards to determine whether the taxonomic status of these killer whale ecotypes should be revised. Our review and new analyses indicate that species-level status is justified in both cases, and we conclude that eastern North Pacific Bigg's killer whales should be recognized as Orcinus rectipinnus (Cope in Scammon, 1869) and resident killer whales should be recognized as Orcinus ater (Cope in Scammon, 1869)., Competing Interests: We declare we have no competing interests., (© 2024 The Authors.)
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- 2024
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15. Spatiotemporal dynamics of the social structure of Indo-Pacific humpback dolphins ( Sousa chinensis ) in Xiamen waters from 2007 to 2019.
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Lu Y, Xu XR, Chen BY, Jefferson TA, Fearnbach H, and Yang G
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- Animals, Ecosystem, China, Dolphins
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As highly social animals, Indo-Pacific humpback dolphins ( Sousa chinensis ) exhibit community differentiation. Nevertheless, our understanding of the external and internal factors influencing these dynamics, as well as their spatiotemporal variations, is still limited. In the present study, variations in the social structure of an endangered Indo-Pacific humpback dolphin population in Xiamen Bay, China, were monitored over two distinct periods (2007-2010 and 2017-2019) to analyze the effects of habitat utilization and the composition of individuals within the population. In both periods, the population demonstrated a strikingly similar pattern of social differentiation, characterized by the division of individuals into two main clusters and one small cluster. Spatially, the two primary clusters occupied the eastern and western waters, respectively, although the core distribution area of the eastern cluster shifted further eastward between the two periods. Despite this distribution shift, the temporal stability of the social structure and inter-associations within the eastern cluster remained unaffected. A subset of 16 individuals observed in both periods, comprising 51.6% and 43.2% of the population in each respective period, emerged as a foundational element of the social structure and may be responsible for sustaining social structure stability, especially during the 2007-2010 period. These observations suggest that the composition of dominant individuals, an internal factor, had a more substantial influence on the formation of the social network than changes in habitat use, an external factor. Consequently, the study proposes distinct conservation measures tailored to each of the two main clusters.
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- 2024
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16. Geographic range size, water temperature, and extrinsic threats predict the extinction risk in global cetaceans.
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Chen C, Jefferson TA, Chen B, and Wang Y
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- Body Weight, Chlorophyll, Conservation of Natural Resources, Humans, Phylogeny, Temperature, Water, Ecosystem, Extinction, Biological
- Abstract
Despite the fact that cetaceans provide significant ecological contributions to the health and stability of aquatic ecosystems, many are highly endangered with nearly one-third of species assessed as threatened with extinction. Nevertheless, to date, few studies have explicitly examined the patterns and processes of extinction risk and threats for this taxon, and even less between the two subclades (Mysticeti and Odontoceti). To fill this gap, we compiled a dataset of six intrinsic traits (active region, geographic range size, body weight, diving depth, school size, and reproductive cycle), six environmental factors relating to sea surface temperature and chlorophyll concentration, and two human-related threat indices that are commonly recognized for cetaceans. We then employed phylogenetic generalized least squares models and model selection to identify the key predictors of extinction risk in all cetaceans, as well as in the two subclades. We found that geographic range size, sea surface temperature, and human threat index were the most important predictors of extinction risk in all cetaceans and in odontocetes. Interestingly, maximum body weight was positively associated with the extinction risk in mysticetes, but negatively related to that for odontocetes. By linking seven major threat types to extinction risk, we further revealed that fisheries bycatch was the most common threat, yet the impacts of certain threats could be overestimated when considering all species rather than just threatened ones. Overall, we suggest that conservation efforts should focus on small-ranged cetaceans and species living in warmer waters or under strong anthropogenic pressures. Moreover, further studies should consider the threatened status of species when superimposing risk maps and quantifying risk severity. Finally, we emphasize that mysticetes and odontocetes should be conserved with different strategies, because their extinction risk patterns and major threat types are considerably different. For instance, large-bodied mysticetes and small-ranged odontocetes require special conservation priority., (© 2022 John Wiley & Sons Ltd.)
- Published
- 2022
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17. Estimating the stock size of harbor seals (Phoca vitulina richardii) in the inland waters of Washington State using line-transect methods.
- Author
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Jefferson TA, Smultea MA, Ward EJ, and Berejikian B
- Subjects
- Animals, Female, Male, Models, Statistical, Population Density, Seasons, Washington, Phoca
- Abstract
Harbor seals (Phoca vitulina richardii) in the inland waters of Washington were reduced by predator control programs in the twentieth century, but stocks have rebounded since being protected in the 1970s. Three management stocks are recognized, but there is little information on their current abundance. We conducted 38,431 km of aerial line-transect surveys throughout the range of these stocks in 2013-2016, sighting a total of 4,678 groups of harbor seals. Line-transect analysis with Beaufort sea state as a covariate provided estimates of the number of seals in the water. We then incorporated tagging data from 15 instrumented seals to develop correction factors, both for seals missed in the water while diving, and those that were on shore. Tagging data were modeled with generalized linear mixed models to provide estimates of the proportions diving and hauled out. After applying these correction factors, we estimated that the Hood Canal stock contained 1,368 seals (CV = 16.8%), the Southern Puget Sound stock contained 1,976 seals (CV = 20.5%), and the Washington Northern Inland Waters stock contained 7,513 seals (CV = 11.5%). This study presents a non-traditional approach to estimating the size of Washington inland waters harbor seal stocks, which may also be applicable to other species for which survey and tagging data are available., Competing Interests: Two of the authors are associated with scientific consulting companies, Clymene Enterprises LLC [TAJ] and Smultea Environmental Sciences LLC [MS]. This does not alter our adherence to PLOS ONE policies on sharing data and materials.
- Published
- 2021
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18. Genomics of Population Differentiation in Humpback Dolphins, Sousa spp. in the Indo-Pacific Ocean.
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Amaral AR, Chanfana C, Smith BD, Mansur R, Collins T, Baldwin R, Minton G, Parra GJ, Krützen M, Jefferson TA, Karczmarski L, Guissamulo A, Brownell RL, and Rosenbaum HC
- Subjects
- Animals, Biodiversity, Cluster Analysis, Ecosystem, Genetic Variation, Geography, Indian Ocean, Pacific Ocean, Dolphins genetics, Genetics, Population, Genomics
- Abstract
Speciation is a fundamental process in evolution and crucial to the formation of biodiversity. It is a continuous and complex process, which can involve multiple interacting barriers leading to heterogeneous genomic landscapes with various peaks of divergence among populations. In this study, we used a population genomics approach to gain insights on the speciation process and to understand the population structure within the genus Sousa across its distribution in the Indo-Pacific region. We found 5 distinct clusters, corresponding to S. plumbea along the eastern African coast and the Arabian Sea, the Bangladesh population, S. chinensis off Thailand and S. sahulensis off Australian waters. We suggest that the high level of differentiation found, even across geographically close areas, is likely determined by different oceanographic features such as sea surface temperature and primary productivity., (© The American Genetic Association. 2020. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
- Published
- 2020
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19. An Indo-Pacific Humpback Dolphin Genome Reveals Insights into Chromosome Evolution and the Demography of a Vulnerable Species.
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Zhang P, Zhao Y, Li C, Lin M, Dong L, Zhang R, Liu M, Li K, Zhang H, Liu X, Zhang Y, Yuan Y, Liu H, Seim I, Sun S, Du X, Chang Y, Li F, Liu S, Lee SM, Wang K, Wang D, Wang X, McGowen MR, Jefferson TA, Olsen MT, Stiller J, Zhang G, Xu X, Yang H, Fan G, Liu X, and Li S
- Abstract
The Indo-Pacific humpback dolphin ( Sousa chinensis ) is a small inshore species of odontocete cetacean listed as Vulnerable on the IUCN Red List. Here, we report on the evolution of S . chinensis chromosomes from its cetruminant ancestor and elucidate the evolutionary history and population genetics of two neighboring S . chinensis populations. We found that breakpoints in ancestral chromosomes leading to S . chinensis could have affected the function of genes related to kidney filtration, body development, and immunity. Resequencing of individuals from two neighboring populations in the northwestern South China Sea, Leizhou Bay and Sanniang Bay, revealed genetic differentiation, low diversity, and small contemporary effective population sizes. Demographic analyses showed a marked decrease in the population size of the two investigated populations over the last ~4,000 years, possibly related to climatic oscillations. This study implies a high risk of extinction and strong conservation requirement for the Indo-Pacific humpback dolphin., Competing Interests: The authors declare no competing interests., (© 2020 The Authors.)
- Published
- 2020
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20. Trace element concentrations, risks and their correlation with metallothionein genes polymorphism: A case study of narrow-ridged finless porpoises (Neophocaena asiaeorientalis) in the East China Sea.
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Liu J, Chen B, Jefferson TA, Wang H, and Yang G
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- Animals, China, Kidney chemistry, Liver chemistry, Muscles chemistry, Metallothionein genetics, Porpoises genetics, Trace Elements analysis
- Abstract
The concentration of trace elements (TEs) and their risk to narrow-ridged finless porpoises (Neophocaena asiaeorientalis) are still unclear. The present study determined the concentration of typical TEs in liver, kidney, and muscle tissues from porpoises in the East China Sea, assessed potential health risk of TEs to porpoises, and explored the relationship between TE concentration and metallothionein genes (MTs) polymorphism. It was found that Zn, Cu, Mn, Cd and Hg were highly accumulated in liver, and Cd was highly accumulated in kidney. The concentrations of Cr, As, Pb and Ni were very low in all three tissues. TE concentrations showed significant positive correlation with body length, and sexual variation. The levels of most TEs were higher in tissues of porpoises in Ningbo and Nantong than in Pingtan, which is likely related to the local environment pollution level. The risk assessment showed that porpoises from Nantong and Ningbo could face health risks due to Hg, As, Cd, Pb, and Cr exposure. Moreover, two polymorphic sites on the MT4 gene were found to be significantly associated with increased levels of Hg, Cd, Zn and Mn. Whether these two polymorphic sites are involved in expression of MTs, or other functional processes, needs further research., (Copyright © 2016 Elsevier B.V. All rights reserved.)
- Published
- 2017
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21. Indo-Pacific humpback dolphin occurrence north of Lantau Island, Hong Kong, based on year-round passive acoustic monitoring.
- Author
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Munger L, Lammers MO, Cifuentes M, Würsig B, Jefferson TA, and Hung SK
- Abstract
Long-term passive acoustic monitoring (PAM) was conducted to study Indo-Pacific humpback dolphins, Sousa chinensis, as part of environmental impact assessments for several major coastal development projects in Hong Kong waters north of Lantau Island. Ecological acoustic recorders obtained 2711 days of recording at 13 sites from December 2012 to December 2014. Humpback dolphin sounds were manually detected on more than half of days with recordings at 12 sites, 8 of which were within proposed reclamation areas. Dolphin detection rates were greatest at Lung Kwu Chau, with other high-occurrence locations northeast of the Hong Kong International Airport and within the Lung Kwu Tan and Siu Ho Wan regions. Dolphin detection rates were greatest in summer and autumn (June-November) and were significantly reduced in spring (March-May) compared to other times of year. Click detection rates were significantly higher at night than during daylight hours. These findings suggest high use of many of the proposed reclamation/development areas by humpback dolphins, particularly at night, and demonstrate the value of long-term PAM for documenting spatial and temporal patterns in dolphin occurrence to help inform management decisions.
- Published
- 2016
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22. Conservation Status of the Indo-Pacific Humpback Dolphin (Sousa chinensis) in the Northern Beibu Gulf, China.
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Chen B, Xu X, Jefferson TA, Olson PA, Qin Q, Zhang H, He L, and Yang G
- Subjects
- Animals, China, Dolphins injuries, Population Dynamics, Ships, Time Factors, Wounds and Injuries veterinary, Animal Distribution, Behavior, Animal physiology, Conservation of Natural Resources, Dolphins physiology, Ecosystem, Endangered Species
- Abstract
There has been very little previous research on Indo-Pacific humpback dolphins (Sousa chinensis) in the Beibu Gulf of southern China. Here, we report on the population size, habitat and ecology, threats, and overall conservation status of this putative population. 'Population size' was estimated based on photo-identification mark/recapture analysis. It was estimated to number a total of 398-444 individuals (95% CI: 393-506), with two apparently distinct groups in the Dafengjiang-Nanliujiang Estuary and at Shatian-Caotan. Movements of dolphins in the Beibu Gulf appear to be limited, with high site fidelity. These dolphins were found to occur mainly in shallow coastal waters near estuaries. The main threats are fisheries interactions (including by-catch), vessel traffic, mariculture operations, dolphin-watching tourism, and habitat degradation (including marine construction activities and large-scale land reclamation). Although the conservation status of this putative population has been considered to be better than that of other populations of the species in more northern areas of China, there is still reason for strong concern about its future, and several management recommendations are made., (© 2016 Elsevier Ltd. All rights reserved.)
- Published
- 2016
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23. Re-assessment of the Conservation Status of the Indo-Pacific Humpback Dolphin (Sousa chinensis) Using the IUCN Red List Criteria.
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Jefferson TA and Smith BD
- Subjects
- Animals, Dolphins physiology, Ecosystem, Population Dynamics, Species Specificity, Animal Distribution, Conservation of Natural Resources statistics & numerical data, Dolphins classification, Dolphins genetics, Endangered Species
- Abstract
The IUCN Red List designation of the Indo-Pacific humpback dolphin (Sousa chinensis) is re-assessed in light of its newly recognized taxonomic status (it has recently been separated into three species) and findings that humpback dolphins along the coast of Bangladesh, and possibly eastern India, are phylogenetically distinct from other members of the Sousa genus. Sousa chinensis is found in Southeast/South Asia (in both the Indian and Pacific oceans), from at least the southeastern Bay of Bengal east to central China, and then south to the Indo-Malay Archipelago. There are no global population estimates, and the sum of available abundance estimates add up to about 5700 individuals, although only a portion of the range has been covered by surveys. This species occurs in shallow (<30m deep), coastal waters of the tropics and subtropics, and feeds mainly on small fishes. It has a similar reproductive biology to other large dolphins, occurs mostly in small groups, and generally has individual movements of about 50-200km(2). Major threats throughout the range include entanglement in fishing nets (primarily gillnets) and habitat destruction/degradation, although in some more industrialized areas, vessel traffic, and environmental contamination from organochlorines are also serious issues. Conservation management is largely lacking in most parts of the species' range, although there has been significant (though still inadequate) attention in some parts of China (e.g. Hong Kong and adjacent areas, and Taiwan). Much greater efforts are needed toward conservation of Indo-Pacific humpback dolphins to stop apparent declines, and to lower the species' extinction risk. Sousa chinensis meets the IUCN Red List requirements for Vulnerable (under criteria A4cd), with fisheries bycatch and habitat loss/degradation being the main pervasive threats., (© 2016 Elsevier Ltd. All rights reserved.)
- Published
- 2016
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24. Humpback Dolphins (Sousa spp.): Current Status and Conservation, Part 2. Preface.
- Author
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Jefferson TA and Curry BE
- Subjects
- Animal Distribution, Animals, Ecosystem, Conservation of Natural Resources, Dolphins physiology, Endangered Species
- Published
- 2016
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25. Preface.
- Author
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Jefferson TA and Curry BE
- Subjects
- Animals, Conservation of Natural Resources, Dolphins genetics, Ecosystem, Endangered Species, Environmental Monitoring, Internationality, Animal Distribution, Dolphins physiology
- Published
- 2015
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26. Humpback Dolphins: A Brief Introduction to the Genus Sousa.
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Jefferson TA and Curry BE
- Subjects
- Animal Distribution, Animals, Atlantic Ocean, Dolphins anatomy & histology, Dolphins classification, Ecosystem, Endangered Species, Indian Ocean, Pacific Ocean, Population Dynamics, Species Specificity, Dolphins genetics, Dolphins physiology
- Abstract
The delphinid genus Sousa has recently undergone a major revision, and currently contains four species, the Atlantic humpback (Sousa teuszii), Indian Ocean humpback (Sousa plumbea), Indo-Pacific humpback (Sousa chinensis), and Australian humpback (Sousa sahulensis) dolphins. Recent molecular evidence suggests that humpback dolphins in the Bay of Bengal may comprise a fifth species. These moderate-sized dolphin species are found in shallow (<30m), coastal waters of the eastern Atlantic, Indian, and western Pacific oceans. Abundance and trends have only been studied in a few areas, mostly in eastern Africa, China, and northern Australia. No global, empirically derived abundance estimates exist for any of the four species, but none appear to number more than about 20,000 individuals. Humpback dolphins feed mostly on small fishes, and sometimes shrimps; occur for the most part in small groups (mostly 12 or less); have limited nearshore movements; and in most parts of their range exhibit a fission/fusion type of social organization. Major threats that affect all the species are entanglement in fishing gear, and habitat degradation/destruction from various forms of coastal development. Impacts from vessel traffic (including behavioural disturbance and displacement, as well as mortality and morbidity from collisions with vessels) appear to be significant in most areas. Several other threats are apparently significant only in particular parts of the range of some species (e.g. high levels of organochlorine contaminants affecting Indo-Pacific humpback dolphins in Hong Kong). Direct hunting only occurs in limited areas and primarily on a small scale. Conservation actions so far have been limited, with most populations receiving little study and almost no management attention. Much more work is needed on humpback dolphin population status, threats, and how the major threats can be reduced or eliminated. Extinction risks for the four species and some populations are preliminarily re-assessed using the IUCN Red List criteria in the current volume. The results suggest that all four species in the genus are threatened at some level (suggested Red List status ranges from Vulnerable for S. chinensis and S. sahulensis to Critically Endangered for S. teuszii)., (© 2015 Elsevier Ltd All rights reserved.)
- Published
- 2015
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27. Integrating multiple lines of evidence to better understand the evolutionary divergence of humpback dolphins along their entire distribution range: a new dolphin species in Australian waters?
- Author
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Mendez M, Jefferson TA, Kolokotronis SO, Krützen M, Parra GJ, Collins T, Minton G, Baldwin R, Berggren P, Särnblad A, Amir OA, Peddemors VM, Karczmarski L, Guissamulo A, Smith B, Sutaria D, Amato G, and Rosenbaum HC
- Subjects
- Animals, Australia, Cell Nucleus genetics, DNA, Mitochondrial genetics, Dolphins anatomy & histology, Dolphins genetics, Haplotypes, Introns, Multivariate Analysis, Sequence Analysis, DNA, Biological Evolution, Dolphins classification, Phylogeny
- Abstract
The conservation of humpback dolphins, distributed in coastal waters of the Indo-West Pacific and eastern Atlantic Oceans, has been hindered by a lack of understanding about the number of species in the genus (Sousa) and their population structure. To address this issue, we present a combined analysis of genetic and morphologic data collected from beach-cast, remote-biopsied and museum specimens from throughout the known Sousa range. We extracted genetic sequence data from 235 samples from extant populations and explored the mitochondrial control region and four nuclear introns through phylogenetic, population-level and population aggregation frameworks. In addition, 180 cranial specimens from the same geographical regions allowed comparisons of 24 morphological characters through multivariate analyses. The genetic and morphological data showed significant and concordant patterns of geographical segregation, which are typical for the kind of demographic isolation displayed by species units, across the Sousa genus distribution range. Based on our combined genetic and morphological analyses, there is convincing evidence for at least four species within the genus (S. teuszii in the Atlantic off West Africa, S. plumbea in the central and western Indian Ocean, S. chinensis in the eastern Indian and West Pacific Oceans, and a new as-yet-unnamed species off northern Australia)., (© 2013 John Wiley & Sons Ltd.)
- Published
- 2013
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28. The status of the world's land and marine mammals: diversity, threat, and knowledge.
- Author
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Schipper J, Chanson JS, Chiozza F, Cox NA, Hoffmann M, Katariya V, Lamoreux J, Rodrigues AS, Stuart SN, Temple HJ, Baillie J, Boitani L, Lacher TE Jr, Mittermeier RA, Smith AT, Absolon D, Aguiar JM, Amori G, Bakkour N, Baldi R, Berridge RJ, Bielby J, Black PA, Blanc JJ, Brooks TM, Burton JA, Butynski TM, Catullo G, Chapman R, Cokeliss Z, Collen B, Conroy J, Cooke JG, da Fonseca GA, Derocher AE, Dublin HT, Duckworth JW, Emmons L, Emslie RH, Festa-Bianchet M, Foster M, Foster S, Garshelis DL, Gates C, Gimenez-Dixon M, Gonzalez S, Gonzalez-Maya JF, Good TC, Hammerson G, Hammond PS, Happold D, Happold M, Hare J, Harris RB, Hawkins CE, Haywood M, Heaney LR, Hedges S, Helgen KM, Hilton-Taylor C, Hussain SA, Ishii N, Jefferson TA, Jenkins RK, Johnston CH, Keith M, Kingdon J, Knox DH, Kovacs KM, Langhammer P, Leus K, Lewison R, Lichtenstein G, Lowry LF, Macavoy Z, Mace GM, Mallon DP, Masi M, McKnight MW, Medellín RA, Medici P, Mills G, Moehlman PD, Molur S, Mora A, Nowell K, Oates JF, Olech W, Oliver WR, Oprea M, Patterson BD, Perrin WF, Polidoro BA, Pollock C, Powel A, Protas Y, Racey P, Ragle J, Ramani P, Rathbun G, Reeves RR, Reilly SB, Reynolds JE 3rd, Rondinini C, Rosell-Ambal RG, Rulli M, Rylands AB, Savini S, Schank CJ, Sechrest W, Self-Sullivan C, Shoemaker A, Sillero-Zubiri C, De Silva N, Smith DE, Srinivasulu C, Stephenson PJ, van Strien N, Talukdar BK, Taylor BL, Timmins R, Tirira DG, Tognelli MF, Tsytsulina K, Veiga LM, Vié JC, Williamson EA, Wyatt SA, Xie Y, and Young BE
- Subjects
- Animals, Body Size, Conservation of Natural Resources, Databases, Factual, Ecosystem, Marine Biology, Phylogeny, Population Dynamics, Seawater, Biodiversity, Extinction, Biological, Mammals anatomy & histology, Mammals classification, Mammals physiology
- Abstract
Knowledge of mammalian diversity is still surprisingly disparate, both regionally and taxonomically. Here, we present a comprehensive assessment of the conservation status and distribution of the world's mammals. Data, compiled by 1700+ experts, cover all 5487 species, including marine mammals. Global macroecological patterns are very different for land and marine species but suggest common mechanisms driving diversity and endemism across systems. Compared with land species, threat levels are higher among marine mammals, driven by different processes (accidental mortality and pollution, rather than habitat loss), and are spatially distinct (peaking in northern oceans, rather than in Southeast Asia). Marine mammals are also disproportionately poorly known. These data are made freely available to support further scientific developments and conservation action.
- Published
- 2008
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29. Isomer specific determination of hexabromocyclododecanes (HBCDs) in small cetaceans from the South China Sea--Levels and temporal variation.
- Author
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Isobe T, Ramu K, Kajiwara N, Takahashi S, Lam PK, Jefferson TA, Zhou K, and Tanabe S
- Subjects
- Animals, China, Chromatography, Liquid methods, Ecosystem, Environmental Monitoring, Hydrocarbons, Brominated chemistry, Isomerism, Oceans and Seas, Reproducibility of Results, Tandem Mass Spectrometry methods, Time Factors, Adipose Tissue chemistry, Dolphins physiology, Hydrocarbons, Brominated analysis, Porpoises physiology, Water Pollutants, Chemical analysis
- Abstract
A diastereoisomer (alpha, beta, and gamma) specific analytical method for measuring hexabromocyclododecanes (HBCDs) was developed using liquid chromatography-tandem mass spectrometry (LC-MS-MS). The method developed was applied to analyze blubber of small cetaceans to divulge the distribution and temporal variation of HBCDs in the Asian marine environment. HBCDs were detected in all the blubber samples of finless porpoises (Neophocaena phocaenoides) and Indo-Pacific humpback dolphins (Sousa chinensis) collected from the South China Sea during 1990-2001. Concentrations of HBCDs were higher in humpback dolphins (31-380 ng/g lipid) than in finless porpoises (4.7-55 ng/g lipid), which can be attributed to habitat differences. Average concentrations of alpha-HBCD in finless porpoises increased from 9.5 ng/g lipid in 1990 to 35 ng/g lipid in 2000/01. alpha-HBCD was predominant among the three isomers with some exceptions in finless porpoises collected in 1990. This is the first report on HBCDs contamination in marine mammals from Southeast Asia.
- Published
- 2007
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30. Risk assessment of trace elements in the stomach contents of Indo-Pacific Humpback Dolphins and Finless Porpoises in Hong Kong waters.
- Author
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Hung CL, Lau RK, Lam JC, Jefferson TA, Hung SK, Lam MH, and Lam PK
- Subjects
- Animals, Gastric Mucosa metabolism, Hong Kong, Risk Assessment, Trace Elements pharmacokinetics, Water Pollutants, Chemical pharmacokinetics, Dolphins metabolism, Environmental Monitoring methods, Gastrointestinal Contents chemistry, Porpoises metabolism, Trace Elements isolation & purification, Water Pollutants, Chemical isolation & purification
- Abstract
The potential health risks due to inorganic substances, mainly metals, was evaluated for the two resident marine mammals in Hong Kong, the Indo-Pacific Humpback Dolphin (Sousa chinensis) and the Finless Porpoise (Neophocaena phocaenoides). The stomachs from the carcasses of twelve stranded dolphins and fifteen stranded porpoises were collected and the contents examined. Concentrations of thirteen trace elements (Ag, As, Cd, Co, Cr, Cs, Cu, Hg, Mn, Ni, Se, V and Zn) were determined by inductively coupled plasma mass spectrometer (ICP-MS). An assessment of risks of adverse effects was undertaken using two toxicity guideline values, namely the Reference Dose (RfD), commonly used in human health risk assessment, and the Toxicity Reference Value (TRV), based on terrestrial mammal data. The levels of trace metals in stomach contents of dolphins and porpoises were found to be similar. Risk quotients (RQ) calculated for the trace elements showed that risks to the dolphins and porpoises were generally low and within safe limits using the values based on the TRV, which are less conservative than those based on the RfD values. Using the RfD-based values the risks associated with arsenic, cadmium, chromium, copper, nickel and mercury were comparatively higher. The highest RQ was associated with arsenic, however, most of the arsenic in marine organisms should be in the non-toxic organic form, and thus the calculated risk is likely to be overestimated.
- Published
- 2007
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31. Temporal variation and biomagnification of organohalogen compounds in finless porpoises (Neophocaena phocaenoides) from the South China Sea.
- Author
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Ramu K, Kajiwara N, Lam PK, Jefferson TA, Zhou K, and Tanabe S
- Subjects
- Animals, Body Burden, China, Food Chain, Gastrointestinal Contents chemistry, Hong Kong, Male, Time, Adipose Tissue chemistry, Developing Countries, Hydrocarbons, Halogenated analysis, Pesticide Residues analysis, Porpoises metabolism
- Abstract
Polybrominated diphenyl ethers (PBDEs) and organochlorine compounds (OCs) were determined in the blubber of male finless porpoises (Neophocaena phocaenoides) collected in 1990 and 2000/01 from the South China Sea. Among the organohalogen compounds analyzed, DDTs and PCBs were the predominant contaminants in the porpoises, ranging from 26,000 to 260,000 and 1400 to 28,000 ng/g lipid wt., respectively. PBDEs ranged from a minimum of 84 ng/g lipid wt., in 1990 to a maximum of 980 ng/g lipid wt., in 2001, showing a significant increase during the time period investigated. Congener profiles in finless porpoises did not shift to higher BDE congeners during these years, implying a continuous discharge of lower BDE commercial mixtures, such as PentaBDE. For OCs, HCHs concentrations decreased significantly, while others did not exhibit any significant temporal variation. Biomagnification factors (BMFs) were found to be highest for CHLs and lowest for HCB. PBDEs and PCBs had comparable BMFs, indicating a similar potential for biomagnification through the food web.
- Published
- 2006
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32. Geographical distribution of polybrominated diphenyl ethers (PBDEs) and organochlorines in small cetaceans from Asian waters.
- Author
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Kajiwara N, Kamikawa S, Ramu K, Ueno D, Yamada TK, Subramanian A, Lam PK, Jefferson TA, Prudente M, Chung KH, and Tanabe S
- Subjects
- Adipose Tissue chemistry, Animals, Asia, Oceans and Seas, Cetacea, Environmental Monitoring, Hydrocarbons, Chlorinated analysis, Phenyl Ethers analysis, Polybrominated Biphenyls analysis, Water Pollutants, Chemical analysis
- Abstract
Polybrominated diphenyl ethers (PBDEs) are one of the flame retardants widely used in plastics, textiles, electronic appliances, and electrical household appliances. In this study, PBDEs and organochlorine compounds (OCs) were determined in the archived samples from the Environmental Specimen Bank for Global Monitoring (es-BANK) at Ehime University. The blubber of cetaceans found stranded along the coasts of Japan, Hong Kong, the Philippines and India during the period from 1990 to 2001 were employed for chemical analysis to understand the present status of contamination and the specific accumulation of PBDEs. PBDEs were detected in all the cetacean samples analyzed, and concentrations were one or two orders of magnitude lower than for PCBs and DDTs. Concentrations of PBDEs ranged from a low value of 6.0 ng/g lipid wt. in spinner dolphin (Stenella longirostris) from India to a high value of 6000 ng/g lipid wt. in Indo-Pacific humpback dolphin (Sousa chinensis) from Hong Kong. No difference in PBDE levels between coastal and offshore species from Japan was observed, implying the existence of pollution sources in this region other than Japan. Highest concentrations of PBDEs were found in animals from Hong Kong, followed by Japan, and much lower levels from the Philippines and India, suggesting that developing nations may also have pollution sources of PBDEs. Geographical distribution of PBDEs in Asian waters was different from PCBs but similar to DDTs.
- Published
- 2006
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33. An assessment of the risks associated with polychlorinated biphenyls found in the stomach contents of stranded Indo-Pacific Humpback Dolphins (Sousa chinensis) and Finless Porpoises (Neophocaena phocaenoides) from Hong Kong waters.
- Author
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Hung CL, Xu Y, Lam JC, Jefferson TA, Hung SK, Yeung LW, Lam MH, O'Toole DK, and Lam PK
- Subjects
- Animals, Dolphins, Hong Kong, Pacific Ocean, Polychlorinated Biphenyls toxicity, Porpoises, Reference Values, Risk Assessment, Water Pollutants, Chemical toxicity, Gastrointestinal Contents chemistry, Polychlorinated Biphenyls analysis, Water Pollutants, Chemical analysis
- Abstract
The risks to Indo-Pacific Humpback Dolphins and Finless Porpoises associated with polychlorinated biphenyls (PCBs) were assessed. Stomach contents from twelve stranded Humpback Dolphins and sixteen stranded Finless Porpoises were collected. Concentrations of total and isomer-specific PCBs in the stomach contents were determined using dual-column gas chromatography equipped with electron capture detectors (GC-ECD). Risks due to the PCBs were assessed in three scenarios, based on total PCBs (summation of 41 PCB congeners), total toxicity equivalency (TEQs) and PCB 118, using the toxicity reference values (TRVs) as the threshold effects benchmarks. The calculated risk quotients (RQs) showed that risks due to PCBs were generally low or negligible. Specifically, RQs from total TEQs and total PCBs for Finless Porpoises are below one, suggesting that PCBs should be a low risk for the Finless Porpoise in Hong Kong waters. However, the Humpback Dolphin has RQs larger than 1 for total TEQs and total PCBs when the 95th percentile data were used in the evaluation. This indicates that further investigation may be needed to examine more closely the potential impact of toxic contaminants in the habitat of the Humpback Dolphin.
- Published
- 2006
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34. Petroleum hydrocarbons, polycyclic aromatic hydrocarbons, organochlorine pesticides and polychlorinated biphenyls in tissues of Indo-Pacific humpback dolphins from south China waters.
- Author
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Leung CC, Jefferson TA, Hung SK, Zheng GJ, Yeung LW, Richardson BJ, and Lam PK
- Subjects
- Animals, China, Data Collection, Female, Petroleum, Polycyclic Aromatic Hydrocarbons analysis, Risk Assessment, Water Pollutants, Chemical analysis, Adipose Tissue chemistry, Dolphins metabolism, Environmental Pollutants analysis, Hydrocarbons analysis, Pesticides analysis, Polychlorinated Biphenyls analysis
- Published
- 2005
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35. Polybrominated diphenyl ethers (PBDEs) and organochlorines in small cetaceans from Hong Kong waters: levels, profiles and distribution.
- Author
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Ramu K, Kajiwara N, Tanabe S, Lam PK, and Jefferson TA
- Subjects
- Adipose Tissue chemistry, Animals, Gas Chromatography-Mass Spectrometry, Hong Kong, Kidney chemistry, Liver chemistry, Cetacea metabolism, Environmental Monitoring statistics & numerical data, Hydrocarbons, Chlorinated analysis, Phenyl Ethers analysis, Polybrominated Biphenyls analysis, Water Pollutants, Chemical analysis
- Abstract
Polybrominated diphenyl ethers (PBDEs) and organochlorine compounds (OCs) were determined in the blubber, liver and kidney of Indo-Pacific humpback dolphins (Sousa chinensis) and finless porpoises (Neophocaena phocaenoides) stranded in Hong Kong coastal waters during 1995-2001. Among the organohalogen compounds analyzed, DDTs were the most dominant contaminants with concentrations ranging from 9.9 to 470 microg/g lipid wt. PBDEs in Hong Kong cetaceans, which are reported for the first time, were detected in all the samples with values ranging from 0.23 to 6.0 microg/g lipid wt., with a predominance of BDE-47. Results from this study suggest PBDEs should be classified as priority pollutants in Asia. Higher concentrations were found in humpback dolphins than in finless porpoises, and this was attributed mainly to differences in habitat. Elevated residues of PCBs and DDTs in some cetaceans suggest these species may be at risk.
- Published
- 2005
- Full Text
- View/download PDF
36. Parasites from Indo-Pacific hump-backed dolphins (Sousa chinensis) and finless porpoises (Neophocaena phocaenoides) stranded in Hong Kong.
- Author
-
Parsons EC, Overstreet RM, and Jefferson TA
- Subjects
- Animals, Hong Kong, Nematoda ultrastructure, Nematode Infections parasitology, Nematode Infections pathology, Pneumonia parasitology, Pneumonia pathology, Thoracica classification, Dolphins parasitology, Nematoda isolation & purification, Nematode Infections veterinary, Pneumonia veterinary, Porpoises parasitology
- Abstract
Between 1993 and 1998, 28 Indo-Pacific hump-backed dolphins (Sousa chinensis) and 32 finless porpoises (Neophocaena phocoenoides) stranded in Hong Kong territorial waters were examined postmortem for parasites. The nematode Halocercus pingi was discovered in the lungs of one hump-backed dolphin and in 10 finless porpoises, typically within abscesses or granulomata, and they were frequently accompanied by a catarrhal exudate and lesions characteristic of pneumonia. Seven of the 10 finless porpoises were calves with substantial lungworm infections, and three were neonates with visible fetal folds and umbilical remnants, suggesting that H pingi is transferred to the neonate before birth or during lactation. Electron micrographs of H pingi should allow the nematode to be identified by other researchers. An ectoparasitic stalked barnacle (Xenobalanus globicipitis) was recovered from a finless porpoise, the first time that this species of barnacle has been recorded in Hong Kong's territorial waters.
- Published
- 2001
- Full Text
- View/download PDF
37. Widespread contamination by tris(4-chlorophenyl)methane and tris(4-chlorophenyl)methanol in cetaceans from the North Pacific and Asian coastal waters.
- Author
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Minh TB, Watanabe M, Tanabe S, Miyazaki N, Jefferson TA, Prudente MS, Subramanian A, and Karuppiah S
- Abstract
For understanding global distribution, transport and behavior of tris(4-chlorophenyl)methane (TCPMe) and tris(4-chlorophenyl)methanol (TCPMOH), the two newly identified microcontaminants, the present study determined their concentrations and other persistent organochlorines (OCs) in the blubber of nine species of adult male cetaceans collected from various locations in the North Pacific Ocean and coastal waters of some Asian countries, during 1985-97. Concentrations of TCPMe and TCPMOH were found to be highest in northern right whale dolphins, which may be attributable to wide distribution of this species, including some heavily polluted areas such as coastal California. Elevated residue levels of TCPMe and TCPMOH were observed in both off-shore and coastal species, suggesting widespread contamination of these compounds in the marine environment. Higher contamination of TCPMe and TCPMOH was found in cetaceans from temperate and cold waters than those from tropical regions. The latitudinal distribution of TCPMe and TCPMOH in cetaceans from the North Pacific and Asian coastal waters was similar to that of DDTs, suggesting less transportable nature of TCPMe and TCPMOH in the marine environment. Data on the occurrence of TCPMe and TCPMOH further indicated high bioaccumulation potential of these compounds, which was comparable to DDTs. Relative concentrations of TCPMe/TCPMOH in cetaceans were apparently higher than those observed in seals, suggestive of lower metabolic capacity for these compounds in cetaceans than in pinnipeds, which is similar to classic contaminants like polychlorinated biphenyls and DDTs.
- Published
- 2000
- Full Text
- View/download PDF
38. Isomer-specific accumulation and toxic assessment of polychlorinated biphenyls, including coplanar congeners, in cetaceans from the North Pacific and Asian coastal waters.
- Author
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Minh TB, Nakata H, Watanabe M, Tanabe S, Miyazaki N, Jefferson TA, Prudente M, and Subramanian A
- Subjects
- Animals, Male, Pacific Ocean, Polychlorinated Biphenyls analysis, Water Pollutants, Chemical analysis, Cetacea metabolism, Polychlorinated Biphenyls toxicity, Water Pollutants, Chemical toxicity
- Abstract
To elucidate the global distribution and toxicological impacts of polychlorinated biphenyls (PCBs) on cetaceans, the present study determined the concentrations of individual PCB congeners, including toxic non-ortho (IUPAC Nos. 77, 126, 169) and mono-ortho (IUPAC Nos. 105, 118, 156) coplanar congeners, in the blubber of 10 species of adult male odontocetes collected from several locations in the North Pacific Ocean and along coastal waters of Japan, Hong Kong, the Philippines, and India during 1985-1997. Total PCB concentrations in cetaceans from temperate and cold waters were higher than those in cetaceans from tropical regions. Residue levels were found to be the highest in Fraser's dolphins collected off Kii Peninsula, Japan, and hump-backed dolphins from Hong Kong, reflecting serious marine pollution by PCBs in industrialized Asian countries. Penta- and hexa-chlorobiphenyls were the predominant PCB congeners, accounting for about 70% of the total PCBs. 2,3,7,8-Tetrachlorodibenzo-p-dioxin equivalents (TEQs) of non- and mono-ortho coplanar PCBs in the blubber of cetaceans ranged from 36 (in spinner dolphins from the Philippines) to 510 pg/g wet weight (in hump-backed dolphins from Hong Kong). Toxic evaluation of coplanar PCBs using the TEQ concept indicates an greater impact on cetaceans from mid-latitudes. Toxicity contribution of mono-ortho congener IUPAC 118 was prominent in species from high latitude oceans, such as the Bering Sea and the North Pacific, whereas non-ortho congener IUPAC 126 accounted for the highest contribution in cetaceans from lower latitude regions, such as the Philippines and India. The estimated TEQ concentrations in the blubber of some cetacean species, such as northern right whale dolphin and Pacific white-sided dolphin from the northern North Pacific, Dall's porpoise from the Japan Sea, striped dolphin off Sanriku and Fraser's dolphin off Kii Peninsula, Japan, hump-backed dolphin and finless porpoise from Hong Kong, exceeded the levels associated with immunosuppression in harbour seals.
- Published
- 2000
- Full Text
- View/download PDF
39. Post-mortem investigations on stranded dolphins and porpoises from Hong Kong waters.
- Author
-
Parsons EC and Jefferson TA
- Subjects
- Animals, Autopsy veterinary, Female, Hong Kong, Uterine Prolapse mortality, Uterine Prolapse veterinary, Wounds and Injuries etiology, Wounds and Injuries mortality, Wounds and Injuries veterinary, Cause of Death, Dolphins injuries, Porpoises injuries
- Abstract
Stranded cetaceans reported from the territorial waters of Hong Kong during the period May 1993 to March 1998 were examined to establish factors that may have contributed to their death. During the current study, 28 Indo-Pacific hump-backed dolphins (Sousa chinensis), 32 finless porpoises (Neophocaena phocaenoides), and four bottlenose dolphins (Tursiops truncatus) were necropsied. Bacteria (15 species) were isolated from nine animals. Of these bacteria, 47% were of possible fecal origin reflecting the high level of sewage contamination in Hong Kong's waters. One finless porpoise displayed wounds caused by a shark attack, and two female finless porpoises presented prolapsed uteri. At least 10 finless porpoises showed evidence of moderate to heavy lungworm infections (Halocercus pingi), and this appears to have been a factor contributing to death in at least six animals. Evidence suggesting blunt traumatic injury (probably caused by boat collisions) was found in six cetaceans (three finless porpoises and three hump-backed dolphins). Signs of fishery-related mortality were detected in at least nine animals (six hump-backed dolphins, two finless porpoises, and one bottlenose dolphin). Of these two human-caused mortality types, pre-existing disease or bacterial infection were detected in 29% of cases. Results indicate that human factors may have played a significant role in the death of at least 15 animals (32% of hump-backed dolphins, 15% of finless porpoises, and 25% of bottlenose dolphins).
- Published
- 2000
- Full Text
- View/download PDF
40. Development of an air bubble curtain to reduce underwater noise of percussive piling.
- Author
-
Würsig B, Greene CR Jr, and Jefferson TA
- Subjects
- Air, Animals, Hong Kong, Dolphins, Noise, Occupational prevention & control
- Abstract
Underwater bubbles can inhibit sound transmission through water due to density mismatch and concomitant reflection and absorption of sound waves. For the present study, a perforated rubber hose was used to produce a bubble curtain, or screen, around pile-driving activity in 6-8-m depth waters of western Hong Kong. The percussive hammer blow sounds of the pile driver were measured on 2 days at distances of 250, 500, and 1000 m; broadband pulse levels were reduced by 3-5 dB by the bubble curtain. Sound intensities were measured from 100 Hz to 25.6 kHz, and greatest sound reduction by the bubble curtain was evident from 400 to 6400 Hz. Indo-Pacific hump-backed dolphins (Sousa chinensis) occurred in the immediate area of the industrial activity before and during pile driving, but with a lower abundance immediately after it. While hump-backed dolphins generally showed no overt behavioral changes with and without pile driving, their speeds of travel increased during pile driving, indicating that bubble screening did not eliminate all behavioral responses to the loud noise. Because the bubble curtain effectively lowered sound levels within 1 km of the activity, the experiment and its application during construction represented a success, and this measure should be considered for other appropriate areas with high industrial noises and resident or migrating sound-sensitive animals.
- Published
- 2000
- Full Text
- View/download PDF
41. Viability of neuromuscular tissues in hyperbaric gaseous environments containing variable N 2 :He content ratios.
- Author
-
Friess SL, Jefferson TA, and Durant RC
- Subjects
- Animals, Carbon Dioxide, Diaphragm physiology, In Vitro Techniques, Oxygen, Partial Pressure, Rats, Time Factors, Atmospheric Pressure, Helium, Muscles physiology, Nitrogen, Phrenic Nerve physiology
- Published
- 1971
- Full Text
- View/download PDF
42. Cardiovascular and lysosomal actions of corticosteroids in the intact dog.
- Author
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Jefferson TA, Glenn TM, Martin JB, and Lefer AM
- Subjects
- Aldosterone pharmacology, Animals, Desoxycorticosterone pharmacology, Dogs, Glucuronidase metabolism, Hydrocortisone pharmacology, Methylprednisolone pharmacology, Norepinephrine pharmacology, Pancreas enzymology, Vagotomy, Adrenal Cortex Hormones pharmacology, Hemodynamics drug effects, Lysosomes drug effects
- Published
- 1971
- Full Text
- View/download PDF
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