A necessidade de tratamentos mais eficazes e menos invasivos para os pacientes, em adição à capacidade de diferenciação celular da medula óssea sugere que o transplante de células mononucleares totais poderia ser uma das melhores formas de tratamento para as diversas patologias existentes. Entretanto, vários fatores implicam sobre a viabilidade das células da medula óssea dos quais destacamos a ausência de padronização de protocolo de criopreservação que permita a manutenção da viabilidade celular, sendo altamente necessário o desenvolvimento de estudos nesta área. Deste modo, neste estudo, após a anestesia de um grupo de animais foi realizada punção da medula óssea, separação das células mononucleares e avaliação da viabilidade. Foram testados oito meios diferentes para criopreservação das células. O meio de congelamento A é composto por 20% dimetilsulfóxido (DMSO), 40% Dulbecco´s Modified Eagle´s Médium (DMEM) e 40% de Plasma Autólogo, o meio de congelamento B contém 20% dimetilsulfóxido (DMSO), 40% Roswell Park Memorial Institute (RPMI) e 40% de Plasma Autólogo, o meio de congelamento C tem em sua composição 20% dimetilsulfóxido (DMSO), 40% soro fetal bovino (SFB) e 40% plasma autólogo, o meio de congelamento D é composto de 20% dimetilsulfóxido (DMSO) e 80% de plasma autólogo, o meio E constitui-se de 5% dimetilsulfóxido (DMSO), 47,5% de Dulbecco\'s Modified Eagle\'s Médium (DMEM) e 47,5% de plasma autólogo, o meio F contém 5% dimetilsulfóxido (DMSO), 47,5% de Roswell Park Memorial Institute (RPMI) e 47,5% de plasma autólogo, o meio G contém 5% dimetilsulfóxido (DMSO), 47,5% de soro fetal bovino (SFB) e 47,5% de plasma autólogo e o meio H constitui-se de 5% dimetilsulfóxido (DMSO) e 95% de plasma autólogo. Após as análises realizadas pela técnica de citometria de fluxo, o meio mais eficiente na criopreservação das células mononucleares de suínos foi o protocolo D por possuir maior concentração de plasma autólogo e crioprotetor. / The necessity of the most efficient and less invasive treatments for the patients, in addition to the capacity of cellular differentiation of the bone marrow suggests that the transplant of mononuclear total cells might be one of the best treatment for several pathologies. Meantime, several factors influence on the viability of the cells of the bone marrow as the absence of standardization of criopreservação protocol which could allow the maintenance of the cellular viability, being an important issue of investigation. In this study, after the anaesthesia of a group of animals, samples of bone marrow were collected, following the separation of the mononuclear cells and evaluation of the viability. Eight different protocols were tested for cells criopreservation. The protocol A by 20% dimetilsulfóxido (DMSO), 40% Dulbecco\'s Modified Eagle\'s Médium (DMEM) and 40% autologus plasma, B protocol conatained 20% dimetilsulfóxido (DMSO), 40% Roswell Park Memorial Institute (RPMI) and 40% autologus plasma, the C protocol was composed 20 % dimetilsulfóxido (DMSO), 40% bovine fetal serum (SFB) e 40% autologus plasma, D protocol was made using 20% dimetilsulfóxido (DMSO) and 80% autologus plasma, E protocol was constituted by 5% dimetilsulfóxido (DMSO), 47,5% de Dulbecco\'s Modified Eagle\'s Médium (DMEM) and 47,5% autólogo plasma, the F contains 5% dimetilsulfóxido (DMSO), 47,5% de Roswell Park Memorial Institute (RPMI) and 47,5% autologo plasma, the protocol G was compoed by 5% dimetilsulfóxido (DMSO), 47,5% de bovine feta serum (SFB) and 47,5% autologus plasma and the H protocol was 5% dimetilsulfóxido (DMSO) and 95% autologus plasma. After flux citometer analyses, the most efficient protocol in criopreservation of the mononuclear cells of pigs was the protocol D which was composed the by the most amount of autologus plasma and crioprotectant.

Objetivou-se com essa pesquisa analisar o bem-estar animal e o desempenho zootécnico de matrizes suínas nas fases de gestação e maternidade e leitões na fase de maternidade, criadas em sistemas de baias coletivas sem e com acesso a piquete. O experimento foi realizado no setor de suinocultura da PUSP-FC, da Universidade de São Paulo (USP), Campus Fernando Costa, na cidade de Pirassununga, entre os meses de novembro de 2015 e março de 2016, durante a fase reprodutiva das matrizes suínas; gestação e maternidade. Para isso, foram utilizadas 13 matrizes da linhagem TopGen Afrodite® (linhagem formada pelas raças Large White e Landrace), com as mesmas características fisiológicas (segunda ordem de parto), submetidas a um delineamento inteiramente ao acaso. Foram avaliados os índices zootécnicos da cobertura ao desmame (peso; ganho de peso; escore da condição corporal; das matrizes; número de leitões nascidos vivos; número de natimortos; peso inicial dos leitões; peso final dos leitões), indicadores hormonais (coleta do fluido oral - cortisol salivar), fisiológicos de conforto térmico (temperatura de pele nas regiões da cabeça, paleta e lombo), e parâmetros de bem-estar animal (com base no ambiente e em observações do animal). A partir dos resultados constatamos que as avaliações do ambiente físico e incidência de lesão e doença, as concentrações de cortisol e as temperaturas da surperfície corporal não diferiram entre os sistemas (P>0,05); as matrizes e leitões permaneceram a maior parte do tempo inativos com olhos fechados e quando estavam ativos, os animais alojados no sistema de baias coletivas com acesso à piquete externo forragearam mais do que as matrizes alojadas no outro tratamento; em relação ao desempenho zootécnico observou-se que as matrizes tiveram aumento de peso ao longo da gestação (P1; P2), perderam peso durante o período de lactação (P3) e os demais parâmetros não diferiram entre os sistemas de alojamentos (P>0,05). Com isso, conclui-se que as matrizes alojadas em baias coletivas sem e com acesso à piquete externo tiveram um bem-estar e desempenho zootécnico adequado e equivalente. / The objective of this research was to analyze the animal welfare and the zootechnical performance of sows in the gestation and maternity stages, created in group-housed without and with access to external area. The experiment was carried out in no pig industry of PUSP-FC, University of São Paulo (USP), at the Fernando Costa Campus, in the city of Pirassununga, between November 2015 and March 2016, during a reproductive phase of Swine matrices; Pregnancy and maternity. For this, 13 sows of the lineage TopGen Afrodite® (lineage formed by Large White and Landrace races), with the same physiological characteristics, were submitted to a completely random design. The zootechnical indexes of weaning coverage, hormonal weights, hormonal indicators (collection of oral fluid - salivary cortisol), physiological thermal comfort (skin temperature in the heads, palette and loins), and animal welfare parameters (Based on the environment and animal observations). (P> 0.05). From the results obtained in the physical examination and incidence of lesions and diseases, such as cortisol concentrations and body surface temperatures; As permanent sows and piglets in most of the time the products are closed and in which they were found, animals not housed in the system of collective- housed with access to external area foraged more than the matrices housed in the other treatment; (P2), lost weight during the lactation period (P3) and the others did not differ between the housing systems (P> 0.05). Thus, it was concluded that matrices lived in group-housed without and with access to external area had adequate and equivalent welfare and zootechnical performance.

The purpose of this study was to compare the performance and carcass characteristics of swine of four different phenotypes and three USDA grades. Hogs were placed into phenotypic groups of 24 each and penned by group. These pens were ideal, cutability, light muscled, fat, VS US and US The hops were fed a 16% corn and soybean meal ration fortified with appropriate minerals and vitamins. They were housed in a total confinement curtain-sided Kentucky plan building with a partially slatted floor. The hogs were weighed at 6-week intervals throughout the project to monitor average daily gain and pen feed efficiency. Twelve hogs from each pen were slaughtered at approximately 2(0 pounds and the remaining twelve pigs at approximately 230 pounds to determine if differences in performance and carcass characteristics remained consistent or became greater at heavier weights. Carcass weight, backfat at the tenth rib and last rib, length and loin eye area were obtained on each carcass. Data were adjusted to the group means for the heavy and light groups using least squares analysis. The mean for the heavy group was 255 pounds and the mean for light group was 229 pounds. Results of the study showed the ideal pen to have significantly higher (P<.01) average daily gain than all other pens at 229 pounds and significantly higher (P<.01) average daily gain than the cutability, US #2, and US #3 pens at 255 pounds. The two leanest and heaviest muscled pens were cutability and US #1. These two pens had significantly (P<.01) lower fat and larger loin eye area than the light muscled. US #3 and fat pens at 229 pounds. The fat pen had significantly (P.-01) greater backfat, smaller loin eye area, and lower percent muscle than all other pens in the heavy group. The cutability and US #1 pens had significantly higher (P<.01) percent muscle than the light muscled, US #3, and fat pens. The ideal, US #1, and cutability pens had significantly (P<.01) higher lean gain per day on test than all other pens with the exception of the light muscled pen taken to the heavier slaughter weight. The ideal, cutabilitv, and US #1 hogs had the lowest average values for feed per unit of lean gain. The fat pen required 2.5 pounds more feed to produce a pound of loan gain than ideal. cutability or US #1 pens. The US #1 group required 1.50 fewer pounds of feed per pound of lean growth than US #2 and #3 groups. These results indicate that the ideal pen was superior in terms of performance and lean growth. The cutabilitv and US #1 pen were the leanest and heaviest muscled. The fat group was extremely high in backfat, low in loin eye area and the most inefficient in converting feed into lean tissue.

The objectives of this study were to investigate the long-term effects of feeding increasing supplemental levels (20, 120, or 220 mg/kg) of dietary copper (Cu) as tribasic copper chloride (TBCC) or copper sulfate (CuSO4) on performance, antioxidant status, nutrient digestibility, and trace mineral deposition of sows and piglets; as well as to assess nursery dietary Cu levels on growth performance and response to immunological challenge in nursery pigs from sows fed either high or low Cu diets. In the long-term sow experiment, sows fed TBCC diets had greater adjusted weaning weight for litter and piglet (P < 0.10), as well as adjusted litter and piglet weight gain (P < 0.10) when compared to sows that received CuSO4 diets. Increasing dietary Cu level linearly increased live born piglet weight (P = 0.06). Sows fed TBCC diets had lower apparent total tract digestibility (ATTD) of ether extract (P = 0.01) during late gestation, but greater ATTD of dry matter, nitrogen, and phosphorous during lactation (P < 0.05). Increasing Cu levels linearly increased dry matter digestibility in lactating sows (P = 0.02). Milk from sows fed TBCC diets had a greater concentration of protein (P = 0.02) than that from sows fed CuSO4 diets. Increasing Cu levels increased levels of milk fat and Cu (linear, P < 0.05); but linearly decreased lactose and Zn levels (P < 0.05). Lactating sows fed TBCC diets had a greater activity of Cu/Zn superoxide dismutase (SOD) and ceruloplasmin in serum than those fed CuSO4 diets (P < 0.05). Increasing dietary Cu levels increased total and Cu/Zn SOD activity for lactating sows (linear, P < 0.05). Sows fed TBCC diets had lower concentrations of Cu (P = 0.04), but higher concentrations of iron and manganese (P < 0.05) in the liver, when compared to those fed with CuSO4 diets. In addition, liver Cu concentrations increased with increasing dietary Cu levels (linear and quadratic, P < 0.05). Increasing dietary Cu levels resulted in the elevation of concentrations and contents of Cu in the liver of weanling piglets (linear, P < 0.0001). In the nursery pig experiment, pigs from sows fed 120 mg/kg Cu diets had greater ADG from d 0 to 14 (P < 0.05), and tended to have greater ADG in the overall period (P < 0.08), when compared to pigs from sows fed 20 mg/kg Cu diets. During the lipopolysaccharide challenge period, the challenged pigs from sows fed 120 mg/kg Cu had a greater overall rectal temperature than those from sows fed 20 mg/kg Cu (P = 0.01). Also, the challenged pigs fed with 220 mg/kg Cu diets had greater serum tumor necrosis factor-alpha concentration over time as compared to those fed 20 mg/kg Cu diets (P = 0.03). In summary, the TBCC may be a superior Cu source compared to CuSO4 regarding reproductive performance, and higher dietary Cu levels result in greater birth weight of piglets; furthermore, high Cu levels in sow and nursery diets promote growth performance of nursery pigs and affects their responses to immunological challenge.

O desenvolvimento embrionário encontra-se dividido em três etapas nas quais podem ser distinguidas as três estruturas: ovo, embrião e feto. Durante o desenvolvimento ocorrem eventos distintos e alterações morfológicas que dão inicio à vida. Os lipídios desempenham um papel importante no processo de formação, pois tem uma participação específica no desenvolvimento embrionário. A utilização de um conjunto de técnicas poderia auxiliar e decrever melhor os processos de formação e a sinalização molecular do desenvolvimento. Porém, o objetivo proposto neste trabalho foi caracterizar de forma aprimorada (mediante tecnologias apropriadas) o desenvolvimento embrionário de mamíferos, em relação à identificação de grupos lipídios. Para isso, foram estudados 28 fetos e embriões de cães, com idades compreendidas entre os 22 e 55 dias de gestação, obtidos em campanha de castração, além de um feto de suíno de 50 dias de gestação, procedente de um fornecedor comercial (Animal Technologies, Inc.). Foram analisados fígado, coração, cérebro, rins e pulmões de embriões e fetos, valendo-se de tecnologias de imagem (Microscopia Eletrônica de Varredura, Tomografia Computadorizada, Raios-X), e técnicas histológicas (colorações de Hematoxilina e Eosina, Tricrômio de Masson, Ferro Coloidal, Sudan Black) em cães. No suíno realizou-se além das citadas técnicas, a análise lipidômica relizada pela técnica de Electroespraiamento por Dispersão- Imageamento por Espectrometria (DESI-MS Imagem) e, posteriormente, coloração com Hematoxilina e Eosina. As principais conclusões relacionam-se ao emprego de várias tecnologias para descrever o desenvolvimento embrionário e fetal, caracterizando bem o desenvolvimento de estruturas, tais como: os arcos braquiais e as vesículas ópticas e óticas nos embriões, cordas tendíneas no coração, lobos hepáticos e mineralização do tecido ósseo. A vinculação dos lipídios à essas tecnologias permitiu associá-las aos processos de contração miocárdica, formação de surfactante pulmonar e trânsito de metabólitos das células epiteliais. Além disso, permitiram ainda demostrar as distribuições lipídicas em órgãos: Nacetilglutamina no coração, ST (ht22: 0) nos intestinos, AG dímeros no fígado e um amplo número de lipídios PS no sistema nervoso. Conclui-se que, de modo geral, existe grande variabilidade na interação do papel dos lipídios com o desenvolvimento embrionário. / Embryonic development is divided into three stages in which the three structures can be distinguished; egg, embryo and fetus. During development occur distinct events, and morphological changes that start life. Lipids play an important role in the formation process because they have a specific participation in embryonic development. The use of a set of techniques could help and improve the processes of formation and the molecular sign of embryonic development. However, the objective of this work was to characterize the embryonic development of mammals in an improved way (through appropriate technologies), in relation to the identification of lipid groups. For this, 28 fetuses and embryos of dogs, aged between 22 and 55 days of gestation, obtained in a castration campaign, in addition to a fetus of 50 days\' gestation from a commercial supplier (Animal Technologies, Inc.). The liver, heart, brain, kidneys and lungs of embryos and fetuses were analyzed using imaging technologies (Scanning Electron Microscopy, Computed Tomography, X-rays) and histological techniques (Hematoxylin and Eosin stains, Masson\'s Tricomial , Colloidal Iron, Sudan Black) in dogs. In the pig, all the techniques were performed, the lipid analysis revealed by the technique of Dispersion Electrospray - Spectrometry Imaging (DESI-MS Image) and subsequently staining with Hematoxylin and Eosin. The main conclusions are related to the use of several technologies to describe embryonic and fetal development, characterizing well the development of structures such as brachial arches and optic and optical vesicles in embryos, chordae tendineae in the heart, hepatic lobes and tissue mineralization bone. The lipid binding to these technologies has been associated with the processes of myocardial contraction, formation of pulmonary surfactant and transit of epithelial cell metabolites. In addition, they allowed to demonstrate the lipid distributions in organs: specific distributions were shown in organs: N-acetylglutamine in the heart, ST (ht22: 0) in the intestines, AG dimers in the liver, and a large number of PS lipids in the nervous system. We conclude that in general there is great variability in the interaction of the role of lipids with embryonic development.

Abstract not available

This thesis is concerned with studying aspects of the ecology of feral pigs in the wet-dry tropics of the Northern Territory. The data are needed for use in the management of feral pigs to reduce their agricultural and potential epidemiological impact. Particular emphasis is placed on collecting data needed for modelling foot-and-mouth disease in feral pigs, estimating agricultural damage caused by pigs and evaluating control techniques. All fieldwork was conducted in the Douglas Daly district of the Northern Territory.

Recent research shows that human auditory steady-state responses (ASSRs) develop a resonance at 40 Hz and the dramatic amplitude increase of the Pb component of the middle latency response (MLR) accounts for the high amplitude of the ASSR at 40 Hz. The first part of this study aimed to investigate the ASSR resonance characteristics as a function of rate in guinea pigs. A study of the grand average of the peak-to-peak and fundamental frequency amplitudes does indeed show a resonance around 40 Hz in guinea pigs. Unlike human ASSRs, this resonance is very broad (26-52 Hz) and flat. The centrally recorded ASSRs are smaller and tend to have resonances at higher rates compared to temporal signals. The second part of the analysis investigated whether the superposition of transient responses can predict the acquired ASSRs at each corresponding rate. This superposition theory is one of two competing theories on the origin of the ASSRs, with the other centering on the induced phase synchronization of brain waves. In order to test the first theory, transient responses were used to create synthetic ASSRs, which were then compared to the acquired ASSRs via correlation coefficient and phasor analysis. For the 40 Hz ASSR, both temporal and central electrode synthesized ASSRs show a correlation coefficient above 0.80. In the comparison at 20 Hz, the correlation coefficient is very high (about 0.9) in the temporal electrode, yet significantly lower (about 0.7) for the central electrode. Furthermore, at 80 Hz, the correlation coefficient is significantly lower in both temporal and central electrodes (about 0.7). At all rates, the correlation coefficients are highest with low jitter sequences. Finally, phasor analysis was also used to test the superposition theory of the generation of the acquired ASSRs at 20, 40, and 80 Hz. Overall, in the temporal recordings at 40 Hz, the superposition of the MLR responses accurately predicted the acquired 40 Hz ASSR as demonstrated by both magnitude and phase analysis. The recordings made in the central electrode only predicted the acquired ASSR in its phases, with significant differences found in magnitude at its main harmonics. Similarly, at 20 and 80 Hz in both temporal and central electrodes, the synthetic ASSRs did not appear to fully predict the acquired ASSRs. Although the phases were successfully predicted, large magnitude variations were observed. As shown by mean prediction error plots, the acquired ASSRs are best predicted by low jitter sequences, followed by low-medium and medium jitter sequences.

Das Ziel der Untersuchungen in der vorliegenden Arbeit bestand in der Erarbeitung von Datenmaterial zur Bestimmung der Prävalenz von Toxoplasma-gondii-Antikörpern bei Schlachtschweinen und in handelsüblichen Hackfleischproben vom Schwein. Um den Einfluss unterschiedlicher Haltungsbedingungen zu ermitteln, wurde jeder Betrieb anhand einer Checkliste im Rahmen einer Feldstudie überprüft. Die Einteilung der Bestände erfolgte in 5 Kategorien (Kategorie 1: >1000 Tiere, Kategorie 2: >500-1000 Tiere, Kategorie 3: 100-500 Tiere, Kategorie 4: Tiere aus Ökobetrieben, Kategorie 5: Tiere aus einzelbäuerlicher Haltung). Im Zeitraum von Februar 2001 bis August 2002 wurden 1028 Schlachtschweine aus 104 Beständen (958 Mastschweine, 66 Sauen, 4 Spanferkel) schwerpunktmäßig aus dem Landkreis Wittenberg mit Ausnahme der Tiere aus Ökobetrieben in den Schlachtbetrieben beprobt. Als Probematerial dienten Blutserum und aus der Zwerchfellpfeilermuskulatur gewonnener Fleischsaft der Schlachtschweine. Des Weiteren wurden 240 Hackfleischprodukte aus dem Handel beprobt, von denen ebenfalls der Fleischsaft untersucht wurde. Eine weitere Aufgabenstellung der Arbeit bestand darin zu prüfen, ob der als serologischer Test verwendete ELISA neben der Eignung für Blutseren auch zur Untersuchung des Fleischsaftes verwendet werden kann. Es wurde ein ELISA nach SEINEKE (1996) auf der Grundlage eines Tachyzoitenlysates als Antigen verwendet. Die Detektion der gebundenen Antikörper erfolgte durch POD (Meerettichperoxidase)-markierte Anti-Schwein-Antikörper von der Ziege. Zur Bewertung der Messergebnisse wurde ein Indexverfahren herangezogen. Blutserum wurde 1:400, Fleischsaft 1:40 verdünnt. Die Ergebnisse der Studien lassen sich wie folgt zusammenfassen: 1. Die Untersuchungen mit dem verwendeten ELISA bieten eine akzeptable Sicherheit (Korrelationskoeffizient von rs = 0,841) bei hoher Signifikanz, wie aus den Doppelbestimmungen bei 711 Blutproben ermittelt werden konnte. 2. Fleischsaft ist grundsätzlich für die Anwendung des ELISA bei Ermittlung des Toxoplasmagondii- Antikörperstatus geeignet (Korrelationskoeffizient rs = 0,472; p < 0,01). 3. Die Gesamtprävalenz der Serumproben beträgt 20,6% mit dem Cut-off-Wert bei einem Index > 20. Diese Ergebnisse weisen aus, dass ein beachtliches Toxoplasmoserisiko besteht, wenn Schweinefleisch roh verzehrt wird. 4. Bei Betrachtung der einzelnen Bestandskategorien wurden folgende Seroprävalenzen bei Mastschweinen ermittelt: Kategorie 1: 15,4%, Kategorie 2: 7,3%, Kategorie 3: 16,4%, Kategorie 4: 15,1%. Höchste Prävalenzen ergaben sich bei unter individuellen, einzelbäuerlichen Bedingungen gehaltenen Schweinen der Kategorie 5: 52,0%. 5. Bei Sauen muss auf Grund des Alters generell von höheren Prävalenzen ausgegangen werden. Es wurde ein Wert von 27,2% für alle überprüften Sauen ermittelt. 6. Ein reelles Bild über das Vorkommen von Toxoplasma-gondii-Antikörpern kann nur durch die Betrachtung der Einzelbestände ermittelt werden. So findet man in der Gruppe der Ökotiere (Kategorie 4) Prävalenzschwankungen von 1,4% bis 34,6%, sowie zwischen den Mastschweinebeständen der Kategorien 1 bis 3 von 1,6% bis 20,5%. Insofern kann allein aus der Kenntnis der Haltungsform nicht sicher auf ein geringes oder hohes Vorkommen des Parasiten geschlossen werden. 7. Die Feldstudien in den einzelnen Beständen belegen eindeutig den Einfluss der Haltungsbedingungen der Schweine auf die ermittelten Prävalenzen für Toxoplasma gondii. Grundsätzlich konnte festgestellt werden, dass unabhängig von Bestandsgröße und Haltungskategorie der direkte oder indirekte Einfluss von Katzen (z.B. über Ausläufe, Futter, Einstreu) als wesentliche Ursache für die Präsenz des Parasiten angesehen werden muss. 8. Beim Hackfleisch wurde eine Gesamtprävalenz für Toxoplasma-gondii-Antikörper von 5,3% nachgewiesen. Dies belegt das Risiko für Infektionen mit Toxoplasma gondii insbesondere beim Verzehr von rohen bzw. unzureichend erhitzten Schweinefleischerzeugnissen. Die vorliegenden Untersuchungen liefern für ein begrenztes Territorium Datenmaterial zu Prävalenzen von Toxoplasma gondii sowohl für Proben von Schlachtschweinen als auch für Hackfleischproben aus dem Handel. Zur Bewertung des deutschlandweit zu erwartenden Risikos sind jedoch weitere flächendeckende Untersuchungen erforderlich.

This paper focuses on stock markets, including Portugal¡BItaly¡BIreland¡BGreece and Spain, and these are named PIGS by economists. Furthermore, we add the other three countries, U.S.A.¡BU.K. and Germany in this paper for investigating the dependence structure in the stock markets between these countries during the period 2001-2011. We implement a regime-switching copula model based on Gaussian copula, which uses a GARCH specification for the marginal distributions and the Gaussian copula for the joint distribution. Our method combines copulas and regime-switching models to demonstrate dependence sructures in stock markets between these countries. Based on this paper, we have two reports for international investors. First, if the dependency changes over time, the returns of portfolio diversification may be prone to diversification disasters, and the international investors' degrees of diversification can cause higher systemic risk in the period of financial crisis. Second, the phonomenon of the asymmetric dependence exists in financial markets, and we conclude that non-diversification may be better than diversification in the period of financial crisis.