• Title/Summary/Keyword: ocean conditions

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Self-purification Mechanisms in Natural Environments of Korea: I. A Preliminary Study on the Behavior of Organic/Inorganic Elements in Tidal Flats and Rice Fields (자연 정화작용 연구: I. 갯벌과 농지 상층수중 유 ${\cdot}$ 무기 원소의 거동에 관한 예비 연구)

  • Choi, Kang-Won;Cho, Yeong-Gil;Choi, Man-Sik;Lee, Bok-Ja;Hyun, Jung-Ho;Kang, Jeong-Won;Jung, Hoi-Soo
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.5 no.3
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    • pp.195-207
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    • 2000
  • Organic and inorganic characteristics including bacterial cell number, enzyme activity, nutrients, and heavy metals have been monitored in twelve acrylic experimental tanks for two weeks to estimate and compare self-purification capacities in two Korean wet-land environments, tidal flat and rice field, which are possibly different with the environments in other countries because of their own climatic conditions. FW tanks, filled with rice field soils and fresh water, consist of FW1&2 (with paddy), FW3&4 (without paddy), and FW5&6 (newly reclaimed, without paddy). SW tanks, filled with tidal flat sediments and salt water, are SW1&2 (with anoxic silty mud), SW3&4 (anoxic mud), and SW5&6 (suboxic mud). Contaminated solution, which is formulated with the salts of Cu, Cd, As, Cr, Pb, Hg, and glucose+glutamic acid, was spiked into the supernatent waters in the tanks. Nitrate concentrations in supernatent waters as well as bacterial cell numbers and enzyme activities of soils in the FW tanks (except FW5&6) are clearly higher than those in the SW tanks. Phosphate concentrations in the SW1 tank increase highly with time compared to those in the other SW tanks. Removal rates of Cu, Cd, and As in supematent waters of the FW5&6 tanks are most slow in the FW tanks, while the rates in SW1&2 are most fast in the SW tanks. The rate for Pb in the SW1&2 tanks is most fast in the SW tanks, and the rate for Hg in the FW5&6 tanks is most slow in the FW tanks. Cr concentrations decrease generally with time in the FW tanks. In the SW tanks, however, the Cr concentrations decrease rapidly at first, then increase, and then remain nearly constant. These results imply that labile organic materials are depleted in the FW5&6 tanks compared to the FW1&2 and FW3&4 tanks. Removal of Cu, Cd, As from the supernatent waters as well as slow removal rates of the elements (including Hg) are likely due to the combining of the elements with organic ligands on the suspended particles and subsequent removal to the bottom sediments. Fast removal rates of the metal ions (Cu, Cd, As) and rapid increase of phosphate concentrations in the SW1&2 tanks are possibly due to the relatively porous anoxic sediments in the SW1&2 tanks compared to those in the SW3&4 tanks, efficient supply of phosphate and hydrogen sulfide ions in pore wates to the upper water body, complexing of the metal ions with the sulfide ions, and subsequent removal to the bottom sediments. Organic materials on the particles and sulfide ions from the pore waters are the major factors constraining the behaviors of organic/inorganic elements in the supernatent waters of the experimental tanks. This study needs more consideration on more diverse organic and inorganic elements and experimental conditions such as tidal action, temperature variation, activities of benthic animals, etc.

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A STUDY ON THE IONOSPHERE AND THERMOSPHERE INTERACTION BASED ON NCAR-TIEGCM: DEPENDENCE OF THE INTERPLANETARY MAGNETIC FIELD (IMF) ON THE MOMENTUM FORCING IN THE HIGH-LATITUDE LOWER THERMOSPHERE (NCAR-TIEGCM을 이용한 이온권과 열권의 상호작용 연구: 행성간 자기장(IMF)에 따른 고위도 하부 열권의 운동량 강제에 대한 연구)

  • Kwak, Young-Sil;Richmond, Arthur D.;Ahn, Byung-Ho;Won, Young-In
    • Journal of Astronomy and Space Sciences
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    • v.22 no.2
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    • pp.147-174
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    • 2005
  • To understand the physical processes that control the high-latitude lower thermospheric dynamics, we quantify the forces that are mainly responsible for maintaining the high-latitude lower thermospheric wind system with the aid of the National Center for Atmospheric Research Thermosphere-Ionosphere Electrodynamics General Circulation Model (NCAR-TIEGCM). Momentum forcing is statistically analyzed in magnetic coordinates, and its behavior with respect to the magnitude and orientation of the interplanetary magnetic field (IMF) is further examined. By subtracting the values with zero IMF from those with non-zero IMF, we obtained the difference winds and forces in the high-latitude 1ower thermosphere(<180 km). They show a simple structure over the polar cap and auroral regions for positive($B_y$ > 0.8|$\overline{B}_z$ |) or negative($B_y$ < -0.8|$\overline{B}_z$|) IMF-$\overline{B}_y$ conditions, with maximum values appearing around -80$^{\circ}$ magnetic latitude. Difference winds and difference forces for negative and positive $\overline{B}_y$ have an opposite sign and similar strength each other. For positive($B_z$ > 0.3125|$\overline{B}_y$|) or negative($B_z$ < -0.3125|$\overline{B}_y$|) IMF-$\overline{B}_z$ conditions the difference winds and difference forces are noted to subauroral latitudes. Difference winds and difference forces for negative $\overline{B}_z$ have an opposite sign to positive $\overline{B}_z$ condition. Those for negative $\overline{B}_z$ are stronger than those for positive indicating that negative $\overline{B}_z$ has a stronger effect on the winds and momentum forces than does positive $\overline{B}_z$ At higher altitudes(>125 km) the primary forces that determine the variations of tile neutral winds are the pressure gradient, Coriolis and rotational Pedersen ion drag forces; however, at various locations and times significant contributions can be made by the horizontal advection force. On the other hand, at lower altitudes(108-125 km) the pressure gradient, Coriolis and non-rotational Hall ion drag forces determine the variations of the neutral winds. At lower altitudes(<108 km) it tends to generate a geostrophic motion with the balance between the pressure gradient and Coriolis forces. The northward component of IMF By-dependent average momentum forces act more significantly on the neutral motion except for the ion drag. At lower altitudes(108-425 km) for negative IMF-$\overline{B}_y$ condition the ion drag force tends to generate a warm clockwise circulation with downward vertical motion associated with the adiabatic compress heating in the polar cap region. For positive IMF-$\overline{B}_y$ condition it tends to generate a cold anticlockwise circulation with upward vertical motion associated with the adiabatic expansion cooling in the polar cap region. For negative IMF-$\overline{B}_z$ the ion drag force tends to generate a cold anticlockwise circulation with upward vertical motion in the dawn sector. For positive IMF-$\overline{B}_z$ it tends to generate a warm clockwise circulation with downward vertical motion in the dawn sector.

Optimum Culture Density for the Intensive Mass Production in Cyclopoid Copepod, Paracyclopina nana (Cyclopoid 요각류, Paracyclopina nana의 대량배양을 위한 최적밀도)

  • Lee Kyun-Woo;Park Heum-Gi
    • Journal of Aquaculture
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    • v.18 no.1
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    • pp.19-25
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    • 2005
  • This study was performed to investigate the optimum density for the intensive mass production of cyclopoid copepod, Paracyclopina nana in terms of nauplii and adults production. Effect of three development stages on the fecundity of adult female for nauplii production, survival rate of P. nana nauplii with different initial nauplii culture densities for adults production and cannibalistic feeding behavior of P. nana was examined, respectively. The fecundity of adult female by different female, copepodite ana nauplii density in 2 ml water volume decreased with the density of adult female, but was not affected by the density of either copepodite or nauplii. The average daily nauplii production for a adult female in 8 L water volume was $2.3{\times}10^5$ individuals with the incubation density of 7 adult females/ml, and this average value was significantly higher than those values of 0.6 to $1.7\times10^5$ individuals with the incubation density of 1,3,5, 10 adult females/ml (P<0.05). Survival rate of P. nana nauplil with different initial nauplii culture densities in 5 L vessels for 15 days were 32.7, 30.7, 28.9 and $23.0\%$ with the culture density of 50, 100, 150 and 200 inds./ml, respectively, but these were significantly higher than those of values 19.7 and $18.4\%$ with the culture density of 250 and 300 inds./ml (P<0.05). Cannibalistic behavior of P. nana adults on their offspring was observed, but the behavior decreased when phytoplankton was supplemented though there was no statistical difference (P>0.05). These results may indicate that P. nana is adaptable to the hatchery conditions and this species is cultured at the high densities. Optimum culture density for nauplii and adults production of P. nana were 7 adult females/ml and 200 nauplii/ml, respectively.

A Study on Anaerobic Treatment and Energy Recovery Technology of Food Waste by Using Hybrid Anaerobic Reactor (Hybrid Anaerobic Reactor를 이용한 음식물쓰레기의 혐기성처리 및 에너지 회수에 관한 연구)

  • Yoon Young-Bong;Park Jin-Young;Ju Jin-Young;Kim Myung-Ho
    • Journal of environmental and Sanitary engineering
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    • v.20 no.1 s.55
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    • pp.64-75
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    • 2005
  • The total production of food waste was about 11,398ton/day('03) in Korea. Also, food waste was treated by landfill, incineration, reuse and anaerobic digestion. The method of food waste treatment depended primarily on landfill. However, the method of landfill causing social problems was prevented to treat food waste in the first of January 2005.12) Thus, anaerobic digestion is an important method to treat food waste because of possibility of energy recovery as methane gas. In this study, the possibility of food waste treatment containing high organic material and low pH in the one stage anaerobic reactor to save cost and time and energy recovery using $CH_{4}$ gas by the hybrid anaerobic reactor (HAR) was measured. The HAR was designed by combing the merits of the anaerobic filter (AF) to minimize the microorganism shock when food waste of very low pH was injected and up-flow anaerobic sludge blanket (UASB) to prevent from plugging and channeling phenomena by large suspended solids when semi solids were injected. Granule was packed in the section of HAR. The purpose of the BMP experiment was to measure the amount of methane generated when organic material was resolved under anaerobic conditions, to grasp bio resolution of organic material. Total accumulated methane production per VS amount was $0.471(m^{3}/\cal{kg}\;VS)$. So, the value was about $81.2\%$ of theoretical methane production which was $0.58(m^{3}/\cal{kg}\;VS)$ by elementary analysis and organic matter removal velocity (K) was $0.18(d^{-1})$. From these results, food waste was treated by anaerobic treatment. From this study, $CH_{4}$ generation from food waste (11,398 ton/day) could be estimated. By using an energy conversion factor of Braun's study, $5.97KWh/m^{3}\;CH4,\;60\%\;of\;CH_{4}$ gas generation, the amount of total energy producing food waste is to 6,727MWh/day. It could be confirmed that energy recovery using $CH_{4}$ gas was possible. Above these results, food waste containing organic matters of high concentration could be treated in HRT 30 days under an anaerobic condition, using the hybrid anaerobic reactor and reuse of $CH_{4}$ gas was possible.

Ecophysiological Studies on the Population Dynamics of Two Toxic Dinoflagellates Alexandrium tamarense and Alexandrium catenella Isolated from the Southern Coast of Korea -I. Effects of Temperature and Salinity on the Growth (남해연안해역에서 분리한 유독와편모조류 Alexandrium tamarense와 Alexandrium catenella의 개체군 변화에 관한 생리.생태학적 연구 -I. 수온과 염분의 변화에 따른 성장 특성)

  • Oh, Seok-Jin;Park, Ji-A;Kwon, Hyeong-Kyu;Yang, Han-Soeb;Lim, Weol-Ae
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.15 no.2
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    • pp.133-141
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    • 2012
  • Effects of temperature and salinity on the growth of the toxic dinoflagellate $Alexandrium$ $tamarense$ and $A.$ $catenella$ isolated from the southern coast of Korea were examined in the laboratory. Growth experiment was conducted under the following combinations of temperature and salinity; 10, 15, 20, 25 and $30^{\circ}C$, 10, 15, 20, 25, 30 and 35 psu at a constant irradiance of 300 ${\mu}mol$ photons $m^{-2}s^{-1}$. Temperature and salinity conditions for maximum growth rate were indicated as follows: temperature $15^{\circ}C$ and salinity 30 psu (0.31 $d^{-1}$) in $A.$ $tamarense$, temperature $25^{\circ}C$ and salinity 30 psu (0.36 $d^{-1}$) in A. catenella. Temperature and salinity ranges for optimum growth condition of two species were $10{\sim}20^{\circ}C$, 25~35 psu and $120{\sim}30^{\circ}C$, 25~35 psu, respectively. The result of two-factor ANOVA indicated significant effects (P<0.001) of temperature and salinity on the growth rate, and two species were more effected by a temperature than a salinity on the growth. In addition, prediction equations were obtained through the multiple regressions of the specific growth rates as ${\mu}=0.04+0.0193T-0.0339S- 0.0005T^2+0.0021S^2+0.00073TS-0.000022T^3-0.000038S^3+0.00000086TS^2-0.0000255T^2S$ in $A.$ $tamarense$ and ${\mu}=1.01-0.1288T-0.0778S+0.0067T^2+0.0038S^2+0.00204TS-0.0001T^3-0.000059S^3-0.0000131TS^2-0.0000392T^2S$ in $A.$ $catenella$. Correlation coefficient between experimental values and simulated values was highly indicated. These results seem to provide information for understanding the spreading mechanism of $A.$ $tamarense$ and $A.$ $catenella$.

The research for the yachting development of Korean Marina operation plans (요트 발전을 위한 한국형 마리나 운영방안에 관한 연구)

  • Jeong Jong-Seok;Hugh Ihl
    • Journal of Navigation and Port Research
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    • v.28 no.10 s.96
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    • pp.899-908
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    • 2004
  • The rise of income and introduction of 5 day a week working system give korean people opportunities to enjoy their leisure time. And many korean people have much interest in oceanic sports such as yachting and also oceanic leisure equipments. With the popularization and development of the equipments, the scope of oceanic activities has been expanding in Korea just as in the advanced oceanic countries. However, The current conditions for the sports in Korea are not advanced and even worse than underdeveloped countries. In order to develop the underdeveloped resources of Korean marina, we need to customize the marina models of advanced nations to serve the specific needs and circumstances of Korea As such we have carried out a comparative analysis of how Austrailia, Newzealand, Singapore, japan and Malaysia operate their marina, reaching the following conclusions. Firstly, in marina operations, in order to protect personal property rights and to preserve the environment, we must operate membership and non-membership, profit and non-profit schemes separately, yet without regulating the dress code entering or leaving the club house. Secondly, in order to accumulate greater value added, new sporting events should be hosted each year. There is also the need for an active use of volunteers, the generation of greater interest in yacht tourism, and the simplification of CIQ procedures for foreign yachts as well as the provision of language services. Thirdly, a permanent yacht school should be established, and classes should be taught by qualified instructors. Beginners, intermediary, and advanced learner classes should be managed separately with special emphasis on the dinghy yacht program for children. Fourthly, arrival and departure at the moorings must be regulated autonomically, and there must be systematic measures for the marina to be able, in part, to compensate for loss and damages to equipment, security and surveillance after usage fees have been paid for. Fifthly, marine safety personnel must be formed in accordance with Korea's current circumstances from civilian organizations in order to be used actively in benchmarking, rescue operations, and oceanic searches at times of disaster at sea.

Temporal and spatial variations of SST and Ocean Fronts in the Korean Seas by Empirical Orthogonal Function (경험직교함수 분석에 의한 한반도 주변해역의 해수면온도 및 수온 전선의 시.공간 변화)

  • Yoon Hong-Joo;Byun Hye-Kyung
    • Proceedings of the KSRS Conference
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    • 2006.03a
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    • pp.101-104
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    • 2006
  • In the Korean seas, Sea Surface Temperature (SST) and Thermal Fronts (TF) were analyzed temporally and spatially during 8 years from 1993 to 2000 using NOAA/AVHRR MCSST. As the result of EOF method applying SST, the variance of the 1st mode was 97.6%. It is suitable to explain SST conditions in the whole Korean seas. Time coefficients were shown annual variations and spatial distributions were shown the closer to the continent the higher SST variations like as annual amplitudes. The 2nd mode presented higher time coefficients of 1993, 94, and 95 than those of other years. Although the influence is a little, that can explain ElNINO effect to the Korean seas. TF were detected by Sobel Edge Detection Method using gradient of SST. Consequently, TF were divided into 4 fronts; the Subpola. Front (SPF) dividing into the north and south part of the East sea, the Kuroshio Front (KF) in the East China Sea (ESC), the South Sea Coastal Front (SSCF) in the South sea, and the Tidal Front in the West sea. TF located in steep slope of submarine topography. The distributions of 1st mode in SST were bounded in the same place, and these results should be considered to influence of seasonal variations. To discover temporal and spatial variations of TF,SST gradient values were analyzed by EOF. The time coefficients fo the 1st mode (variance : 64.55%) showed distinctive annual variations and SPF, KF, and SSCF was significantly appeared in March. the spatial distributions of the 2nd mode showed contrast distribution, as SPF and SSCF had strong '-' value, where KF had strong '+' value. The time of '+' and '-' value was May and October, respectively. Time coefficients of the 3rd mode had 2 peaks per year and showed definite seasonal variations. SPF represented striking '+' value which time was March and October That was result reflected time of the 1st and 2nd mode. We can suggest specific temporal and spatial variations of TF using EOF.

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A Study on the Marine Design Base of Marine Leisure Facilities in Southeast Area of Korea - Focusing on the investigation of marine leisure facilities - (동남권 해양레저시설의 해양디자인기반에 관한 연구 - 해양레저시설 조사 중심으로 -)

  • Park, Kwang-Cheol
    • Management & Information Systems Review
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    • v.33 no.5
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    • pp.185-212
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    • 2014
  • This study investigated the base of marine leisure facilities and studied the future vision for development of marine industry by conducting a systematic analysis on the category of marine leisure products for development of design and specialization of southeast area of Korea. If the age of $20,000 of per capita national income is called 'the age of my car', $20,000 of per capita national income is called 'the age of my boat'. According to the report of UK-based Marine South East, the scale of world's small boat and personal waterborne equipment reached 277 trillion won in 2010 and domestic market scale is expected to be 11 trillion won. Marine leisure facilities are the new growth engine industry that the government should promote as a nation's strategic and core industry, and the government is pushing ahead with promotion of marine industry actively by announcing Marine Leisure Equipment Industry Activation Plan(June 2009, Ministry of Knowledge Economy), Marine Leisure Activation Plan(July 2010, Ministry of Land, Infrastructure and Transport), The 1st General Plan for Marina Port(January 2010, Ministry of Land, Infrastructure and Transport) etc. The purpose of marine design lies in seeking the status of the country and qualitative value in human life through functional, artistic, industrial and cultural development of design elements for all marine activities made around the sea. Related to all activities made in the ocean and cost, marine design is a sphere of design that includes special conditions centering around water. Considering the condition that 3 sides of land are facing the sea, this study systematically analyzed present condition of equipment possessed by each area, type of facilities, operational status, current status of sectoral use of marine leisure facilities and future prospect of marine leisure products that become the basis of value to raise the statue as an advanced marine power in 2010s through development of the qualitative level of the people, establishment of the direction of national strategy, convergence of industry and culture and specialization of area focusing on the actual condition survey of marine leisure facilities. Especially, this study will be predicting the basis of strategy for strengthening marketability and competitiveness by suggesting role and process of design in developing a promising marine leisure product through an actual condition survey of marine leisure products of southeast area.

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A Study on the legal position of the carrier under the right of stoppage in transit of CISG (국제물품매매계약(CISG)의 운송유보권 하에서 운송인의 법적지위에 관한 연구)

  • Lim, Jaewook
    • International Commerce and Information Review
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    • v.16 no.3
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    • pp.159-182
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    • 2014
  • CISG Article 71 (1) states that a party may suspend the performance of his obligations if, after the conclusion of the contract, it becomes apparent that the other party will net perform a substantial part of his obligations as a result of a serious deficiency in his ability to perform or in his creditworthiness or his conduct in preparing to perform or in perfoming the contract. CISG Article 71 (2) states a 'right of stoppage in transit' that if the seller has already dispatched the goods before the grounds described in the preceding paragraph become evident, he may prevent the handing over of the goods to the buyer even though the buyer holds a document which entitles him to obtain them. The present paragraph relates only to the rights in the goods as between the buyer and the seller. Under the right of stoppage in transit, the carrier copes with risks that the seller may claim damages arose from the handing over the goods, if he hand over the goods to the buyer and that the buyer may claim damages, if he deny handing over the goods to the buyer who has the document which entitles him to obtain the goods. Therefore the legal position of the carrier may become weak. This paper purpose to point out the legal weakness of the carrier under the right of stoppage in transit and to provide the proper legal act of the carrier and possible practice related to various characters of the contract of sale of the goods. Although there is the opinion it prevent from handing over the goods to the buyer actually under the interpretation that the buyer should take claim damages to the seller, if the goods are handed over to the buyer under the right of stoppage in transit, it is not appropriate because the opinion may disable the right of stoppage in transit. The right of stoppage in transit could be carried out under any payment conditions except letter of credit and under any mode of transportation except the cases that carrier is the buyer himself or the agent of the buyer. It could be executed regardless the forms of the transport document.

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Reproductive Performance of Holstein Dairy Cows Grazing in Dry-summer Subtropical Climatic Conditions: Effect of Heat Stress and Heat Shock on Meiotic Competence and In vitro Fertilization

  • Pavani, Krishna;Carvalhais, Isabel;Faheem, Marwa;Chaveiro, Antonio;Reis, Francisco Vieira;da Silva, Fernando Moreira
    • Asian-Australasian Journal of Animal Sciences
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    • v.28 no.3
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    • pp.334-342
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    • 2015
  • The present study was designed to evaluate how environmental factors in a dry-summer subtropical climate in Terceira-Azores (situated in the North Atlantic Ocean: $38^{\circ}43^{\prime}N27^{\circ}12^{\prime}W$) can affect dairy cow (Holstein) fertility, as well as seasonal influence on in vitro oocytes maturation and embryos development. Impact of heat shock (HS) effects on in vitro oocyte's maturation and further embryo development after in vitro fertilization (IVF) was also evaluated. For such purpose the result of the first artificial insemination (AI) performed 60 to 90 days after calving of 6,300 cows were recorded for one year. In parallel, climatic data was obtained at different elevation points (n = 5) from 0 to 1,000 m and grazing points from 0 to 500 m, in Terceira island, and the temperature humidity index (THI) was calculated. For in vitro experiments, oocytes (n = 706) were collected weekly during all year, for meiotic maturation and IVF. Further, to evaluate HS effect, 891 oocytes were collected in the cold moths (December, January, February and March) and divided in three groups treated to HS for 24 h during in vitro maturation at: C (Control = $38.5^{\circ}C$), HS1 ($39.5^{\circ}C$) and HS2 ($40.5^{\circ}C$). Oocytes from each group were used for meiotic assessment and IVF. Cleavage, morula and blastocyst development were evaluated respectively on day 2, 6, and 9 after IVF. A negative correlation between cow's conception rate (CR) and THI in grazing points (-91.3%; p<0.001) was observed. Mean THI in warmer months (June, July, August and September) was $71.7{\pm}0.7$ and the CR ($40.2{\pm}1.5%$) while in cold months THI was $62.8{\pm}0.2$ and CR was $63.8{\pm}0.4%$. A similar impact was obtained with in vitro results in which nuclear maturation rate (NMR) ranged from 78.4% (${\pm}8.0$) to 44.3% (${\pm}8.1$), while embryos development ranged from 53.8% (${\pm}5.8$) to 36.3% (${\pm}3.3$) in cold and warmer months respectively. In vitro HS results showed a significant decline (p<0.05) on NMR of oocytes for every $1^{\circ}C$ rising temperature ($78.4{\pm}8.0$, $21.7{\pm}3.1$ and $8.9{\pm}2.2$, respectively for C, HS1, and HS2). Similar results were observed in cleavage rate and embryo development, showing a clear correlation (96.9 p<0.05) between NMR and embryo development with respect to temperatures. Results clearly demonstrated that, up to a THI of 70.6, a decrease in the CR occurs in first AI after calving; this impairment was confirmed with in vitro results.