973 resultados para 7-61


Relevância:

100.00% 100.00%

Publicador:

Relevância:

70.00% 70.00%

Publicador:

Resumo:

Molecular diagnosis of canine bartonellosis can be extremely challenging and often requires the use of an enrichment culture approach followed by PCR amplification of bacterial DNA. HYPOTHESES: (1) The use of enrichment culture with PCR will increase molecular detection of bacteremia and will expand the diversity of Bartonella species detected. (2) Serological testing for Bartonella henselae and Bartonella vinsonii subsp. berkhoffii does not correlate with documentation of bacteremia. ANIMALS: Between 2003 and 2009, 924 samples from 663 dogs were submitted to the North Carolina State University, College of Veterinary Medicine, Vector Borne Diseases Diagnostic Laboratory for diagnostic testing with the Bartonella α-Proteobacteria growth medium (BAPGM) platform. Test results and medical records of those dogs were retrospectively reviewed. METHODS: PCR amplification of Bartonella sp. DNA after extraction from patient samples was compared with PCR after BAPGM enrichment culture. Indirect immunofluorescent antibody assays, used to detect B. henselae and B. vinsonii subsp. berkhoffii antibodies, were compared with PCR. RESULTS: Sixty-one of 663 dogs were culture positive or had Bartonella DNA detected by PCR, including B. henselae (30/61), B. vinsonii subsp. berkhoffii (17/61), Bartonella koehlerae (7/61), Bartonella volans-like (2/61), and Bartonella bovis (2/61). Coinfection with more than 1 Bartonella sp. was documented in 9/61 dogs. BAPGM culture was required for PCR detection in 32/61 cases. Only 7/19 and 4/10 infected dogs tested by IFA were B. henselae and B. vinsonii subsp. berkhoffii seroreactive, respectively. CONCLUSIONS AND CLINICAL IMPORTANCE: Dogs were most often infected with B. henselae or B. vinsonii subsp. berkhoffii based on PCR and enrichment culture, coinfection was documented, and various Bartonella species were identified. Most infected dogs did not have detectable Bartonella antibodies.

Relevância:

70.00% 70.00%

Publicador:

Resumo:

Miocene paleoceanographic evolution exhibits major changes resulting from the opening and closing of passages, the subsequent changes in oceanic circulation, and development of major Antarctic glaciation. The consequences and timing of these events can be observed in variations in the distribution of deep-sea hiatuses, sedimentation patterns, and biogeographic distribution of planktic organisms. The opening of the Drake Passage in the latest Oligocene to early Miocene (25-20 Ma) resulted in the establishment of the deep circumpolar current, which led to thermal isolation of Antarctica and increased global cooling. This development was associated with a major turnover in planktic organisms, resulting in the evolution of Neogene assemblages and the eventual extinction of Paleogene assemblages. The erosive patterns of two widespread hiatuses (PH, 23.0-22.5 Ma; and NH 1, 20-18 Ma) indicate that a deep circumequatorial circulation existed at this time, characterized by a broad band of carbonate-ooze deposition. Siliceous sedimentation was restricted to the North Atlantic and a narrow band around Antarctica. A major reorganization in deep-sea sedimentation and hiatus distribution patterns occurred near the early/middle Miocene boundary, apparently resulting from changes in oceanic circulation. Beginning at this time, deep-sea erosion occurred throughout the Caribbean (hiatus NH 2, 16-15 Ma), suggesting disruption of the deep circumequatorial circulation and northward deflection of deep currents, and/or intensification of the Gulf Stream. Sediment distribution patterns changed dramatically with the sudden appearance of siliceous-ooze deposition in the marginal and east equatorial North Pacific by 16.0 to 15.5 Ma, coincident with the decline of siliceous sedimentation in the North Atlantic. This silica switch may have been caused by the introduction of Norwegian Overflow Water into the North Atlantic acting as a barrier to outcropping of silica-rich Antarctic Bottom Water. The main aspects of the present oceanic circulation system and sediment distribution pattern were established by 13.5 to 12.5 Ma (hiatus NH 3), coincident with the establishment of a major East Antarctic ice cap. Antarctic glaciation resulted in a broadening belt of siliceous-ooze deposition around Antarctica, increased siliceous sedimentation in the marginal and east equatorial North Pacific and Indian Oceans, and further northward restriction of siliceous sediments in the North Atlantic. Periodic cool climatic events were accompanied by lower eustatic sea levels and widespread deep-sea erosion at 12 to 11 Ma (NH 4), 10 to 9 Ma (NH 5), 7.5 to 6.2 Ma (NH 6), and 5.2 to 4.7 Ma (NH 7).

Relevância:

70.00% 70.00%

Publicador:

Resumo:

Densities of layer 2 basalt recovered during the Deep Sea Drilling Project have been found to decrease steadily with age, a finding ascribed to progressive submarine weathering in the context of sea-floor spreading. The least-squares solution for 52 density measurements gives a rate of decrease in density of (Delta p)/(Delta t) = -0.0046 g per ccm m.y. = -16 percent per 100 m.y., which is in excellent agreement with earlier estimates based on observed chemical depletion rates of dredged oceanic basalt. Weathering of sea-floor basalt, should it penetrate to any considerable depth in layer 2, will decrease layer 2 seismic refraction velocities, act as a source of geothermal heat, and substantially influence the chemistry of sea water and the overlying column of sediment.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

STUDY DESIGN: Reliability and case-control injury study. OBJECTIVES: 1) To determine if a novel device, designed to measure eccentric knee flexors strength via the Nordic hamstring exercise (NHE), displays acceptable test-retest reliability; 2) to determine normative values for eccentric knee flexors strength derived from the device in individuals without a history of hamstring strain injury (HSI) and; 3) to determine if the device could detect weakness in elite athletes with a previous history of unilateral HSI. BACKGROUND: HSIs and reinjuries are the most common cause of lost playing time in a number of sports. Eccentric knee flexors weakness is a major modifiable risk factor for future HSIs, however there is a lack of easily accessible equipment to assess this strength quality. METHODS: Thirty recreationally active males without a history of HSI completed NHEs on the device on 2 separate occasions. Intraclass correlation coefficients (ICCs), typical error (TE), typical error as a co-efficient of variation (%TE), and minimum detectable change at a 95% confidence interval (MDC95) were calculated. Normative strength data were determined using the most reliable measurement. An additional 20 elite athletes with a unilateral history of HSI within the previous 12 months performed NHEs on the device to determine if residual eccentric muscle weakness existed in the previously injured limb. RESULTS: The device displayed high to moderate reliability (ICC = 0.83 to 0.90; TE = 21.7 N to 27.5 N; %TE = 5.8 to 8.5; MDC95 = 76.2 to 60.1 N). Mean±SD normative eccentric flexors strength, based on the uninjured group, was 344.7 ± 61.1 N for the left and 361.2 ± 65.1 N for the right side. The previously injured limbs were 15% weaker than the contralateral uninjured limbs (mean difference = 50.3 N; 95% CI = 25.7 to 74.9N; P < .01), 15% weaker than the normative left limb data (mean difference = 50.0 N; 95% CI = 1.4 to 98.5 N; P = .04) and 18% weaker than the normative right limb data (mean difference = 66.5 N; 95% CI = 18.0 to 115.1 N; P < .01). CONCLUSIONS: The experimental device offers a reliable method to determine eccentric knee flexors strength and strength asymmetry and revealed residual weakness in previously injured elite athletes.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

The last four decades have seen a significant increase in the incidence of non-Hodgkin's lymphoma (NHL) as a possible result of increasing environmental carcinogen exposure, particularly pesticides and solvents. Based on the increasing evidence for an association between carcinogen exposure-related cancer risk and xenobiotic gene polymorphisms, we have undertaken a case-control study of xenobiotic gene polymorphisms in individuals with a diagnosis of NHL. Polymorphisms of six xenobiotic genes (CYP1A1, GSTT1, GSTM1, PON1, NAT1, NAT2) were characterized in 169 individuals with NHL and 205 normal controls using polymerase chain reaction-based methods. Polymorphic frequencies were compared using Fisher's exact tests, and odds ratios for NHL risk were calculated. Among the NHL group, the incidence of GSTT1 null and PON1 BB genotypes were significantly increased compared with controls, 34% vs 14%, and 24% vs 11% respectively. Adjusted odds ratios calculated from multivariate analyses demonstrated that GSTT1 null conferred a fourfold increase in NHL risk (OR = 4.27; 95% CI, 2.40-7.61, P < 0.001) and PON1 BB a 2.9-fold increase (OR = 2.92; 95% CI, 1.49-5.72, P = 0.002). Furthermore, GSTT1 null combined with PON1 BB or GSTM1 null conferred an additional risk of NHL. This is the first time that a PON1 gene polymorphism has been shown to be associated with cancer risk. We conclude that the two polymorphisms, GSTT1 null and PON1 BB, are common genetic traits that pose low individual risk but may be important determinants of overall population NHL risk, particularly among groups exposed to NHL-related carcinogens.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

The thermodynamic properties of liquid unsaturated Co--O solutions have been determined by electrochemical measurements using (Y sub 2 O sub 3 )ThO sub 2 as solid electrolyte. The cell can be represented as, Pt. MoO sub 2 + Mo | (Y sub 2 O sub 3 )ThO sub 2 | O sub Co , tungsten, Pt, Emf of the cell was measured as a function of oxygen concentration in liquid Co at 1798, 1873 and 1973K. Least-mean squares regression analysis of the experimental data gives for the free energy of solution of diatomic oxygen in liquid Co Delta G exp 0 sub O(Co) = --84935--7.61 T ( plus/minus 400) J/g-atom and self interaction parameter for oxygen epsilon exp O sub O = --97240/T + 40.52 ( plus/minus 1) where the standard state for O is an infinitely dilute solution in which the activity is equal to atomic percent. The present data are discussed in comparison with those reported in the literature and the phase diagram for the Co--O system. 18 ref.--AA.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

随着全球环境的变化,人们迫切的希望了解整个地球环境的变化过程、规律和未来发展的趋势。对地质历史时期发生过的环境事件的了解,能为我们研究现在的和预测未来的环境变化提供有价值的资料。 孢粉分析作为一种古环境的代用指标,在恢复古植被与古气候方面起着不可替代的作用。而精确的孢粉分析建立在对现代花粉与当地植被的关系正确的认识基础上,由此才可以更准确地提取地层中的花粉所蕴含的植被和环境信息。 云南省地理位置较特殊,地貌复杂,气候类型多样,与之对应的植物种类多样性丰富,植被类型多样。本项研究选择云南省南部和西部地区作为研究地点,采集表土、地表苔藓、蜘蛛网、树皮和树上地衣苔藓五种天然孢粉捕捉器来研究现代花粉与当地植被的关系,为认识现代花粉雨提供新的研究思路。同时,我们在滇西北选择拉市海、文海、哈里谷和属都湖这四个高原湖泊来研究晚更新世以来滇西北地区植被演替和气候变化,为云南历史时期气候变化提供新的研究资料,同时也为全面认识晚更新世以来的气候变化提供新的证据。研究结果如下: 1. 现代花粉雨与当地植被关系的研究 对云南省西北部、中部和南部采集的19个蜘蛛网样品分析得出:云南省西北部样品中共鉴定20个孢粉类型,分属于16个科;云南省中部样品中共鉴定28个类型,分属于23个科;在云南省南部勐腊县采集的样品中共鉴定28个类型,分属于25个科;在望天树北京植物园中采集的样品共鉴定38个类型,分属于34个科;在西双版纳北京植物园中采集的样品中共有11个类型,分属于10个科。结果表明:蜘蛛网样品中分析出的孢粉类型反映了云南省从南到北不同的植被类型,说明蜘蛛网可以作为一种天然孢粉捕捉器来进行现代花粉雨的研究。 同时,在云南西北部文笔水库采集的五种天然孢粉捕捉器(表土、地表苔藓、树皮、蜘蛛网、树上地衣和苔藓)进行了对比研究。结果表明:表土所得的孢粉中木本植物花粉的百分含量为90.5-96%,远大于地表苔藓(53.1-81.7%)、蜘蛛网(61.7%)、树皮(53.8%)和树上地衣、苔藓(50-53.6%)所获得的木本植物花粉的百分含量。与当地植被进行对比结果表明:这五种天然孢粉捕捉器中,表土、地表苔藓和蜘蛛网比树皮和树上地衣、苔藓能更好的反映当地的植被。 2. 滇西北地区晚更新世以来植被演替与气候变化 在过去2, 5000年左右的地质历史时期,滇西北地区植被和气候变化大致经历了以下三个发展阶段。 (1) 2, 5381 B.P—1, 9335 B.P.:属都湖地区(海拔:3620m)主要是以蓼科植物为主的草甸植被,气候寒冷湿润。 (2) 1, 9335 B.P.—1, 2426 B.P.:属都湖地区是以藜科或蒿属为主的草甸植被,气候从湿润过渡到干旱;而在海拔稍低的文海地区(海拔3080m),主要是阔叶栎林或针阔混交林,气候温凉略湿到寒冷干旱。 (3) 1, 2426 B.P.—至今:属都湖地区是以蓼科为主的草甸植被,气候仍寒冷湿润;海拔稍低的哈里谷(海拔3277m)是以松和冷杉为主的针叶林,气候冷干;文海地区的植被逐渐演替为以松和冷杉为主的针阔叶混交林,但栎属花粉的含量远高于哈里谷地区,说明当时文海的气温虽然低,却比哈里谷稍高;而海拔更低的拉市海(海拔2440m)则是以松为主的针叶林,气候比其他几个地区温暖。 在全新世气候最适宜期(约8000 B.P.以来),哈里谷是以栎和松为主的针阔混交林;文海是以松为主的针阔混交林;而拉市海是以松和蕨类植物为主。说明随着海拔的升高(从拉市海到属都湖),温度逐渐下降,植被类型也由暖性针叶林过渡到针阔混交林再到草甸。 从6000 B.P.至今,文海和哈里谷植被在这一阶段都是以松和冷杉为主的暗针叶林,少量混生一些阔叶类植物,气候变得冷湿;属都湖则仍是以蓼科为主的草甸,气候变得更加寒冷。 研究证明:滇西北地区总的气候变化趋势与全球变化规律基本一致,在1,1805—9990 B.P.期间发生新仙女木事件,在8000B.P.以来,气候变得温暖湿润,为全新世气候最适宜期。此后,气候逐渐变得接近现代。

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Studies on reproductive biology and artificial propagation including larval rearing of freshwater mud eel, Monopterus cuchia and spiny eel, Mastacembelus armatus were attempted. The gonadosomatic index (GSI) of mud eel ranged from 0.41 (August) to 5.52 (June) in males and 0.53 (August) to 7.61 (June) in females. In both cases the GSI showed a peak in June. Fecundity ranged from 228 (TL - 396 mm; W - 78g) to 5510 (TL - 865 mm; W - 630 g). In case of spiny eel, the GSI varied from 0.65 (August) to 8.30 (July) in males and 0.70 (August) to 10.46 (July) in females. GSI showed single peak in July. Fecundity ranged from 570 (TL - 240 mm; W - 30 g) to 10870 (TL - 601; W - 350g). Histology of the testes and ovaries of the eels were carried out to investigate the gonadal development stages during the reproductive months (August to November 2003). In case of male M. cuchia, the secondary primordial germ cells, primary spermatogonium, some spermatogonia A and clone of spermatogonium B in testis were observed in September. In October-males different sized lobules having spermatogonia, spermatocytes and spermatids were observed. In the ovary of M. cuchia, polygonal shaped oocytes were seen during September. The oogonia were reduced with dense and irregular shaped during October. Numerous pycnotic cells were visible during November. In male M. armatus numerous broken lobule walls were found in testes during September. In October, abundant primary germ cells, pycnotic nests of degenerating cells, spermatogonia and spermatids were observed. In females, ovaries had distinct yolk vesicles stage and yolk granules stages in August. In September, the follicular cells of the oogonia were ruptured, shrunk forming irregular shaped in October. Oogonia were also shrunk with thin, irregular shaped structure but broken parts of the ruptured follicular cells were scattered in case of M. armatus. Experimental attempts on artificial propagation indicated that both freshwater eels were difficult to breed using inducing agents like pituitary glands (PG) of 10, 20, 50, 100 and 150 mg per kg of body weight. Same doses were used for both sexes with equal sex-ratio. In both cases, brood fish died at higher doses of injection given at 100 and 150 mg PG/kg bodyweight. However, M. cuchia breed naturally in cisterns when provided with water hyacinths and tunnel in muddy bottom. M. cuchia fed with chopped cooked fish attained a mean weight of 18.75 ± 2.3 g and cent percent survival. While in case of M. armatus best growth by weight (12.0 ± 2.48 g) and cent percent survival were achieved using chopped raw fish. Car tyre was observed as best shelter for attaining the mean weight gain 22.53 ± 2.24 g and cent percent survival of M. cuchia. While PVC pipe was found to be the best shelter for M. armatus, where it attained the mean weight of 12.73 ± 1.88 g and cent percent survival.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Analysis of the isothermal, and nonisothermal crystallization kinetics of Nylon-11 is carried out using differential scanning calorimetry. The Avrami equation and that modified by Jeziorny can describe the primary stage of isothermal and nonisothermal crystallization of Nylon-11. In the isothermal crystallization process, the mechanism of spherulitic nucleation and growth are discussed; the lateral and folding surface free energies determined from the Lauritzen-Hoffman equation are sigma = 10.68 erg/cm(2) and sigma(e) = 110.62 erg/cm(2); and the work of chain folding q = 7.61 Kcal/mol. In the nonisothermal crystallization process, Ozawa analysis failed to describe the crystallization behavior of Nylon-ii. Combining the Avrami and Ozawa equations, we obtain a new and convenient method to analyze the nonisothermal crystallization kinetics of Nylon-11; in the meantime, the activation energies are determined to be -394.56 and 328.37 KJ/mol in isothermal and nonisothermal crystallization process from the Arrhonius form and the Kissinger method. (C) 1998 John Wiley & Sons, Inc.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

  研究人类活动、全球变化对河流水质、离子化学特征及分布的影响具有重要意义。河流离子化学组成可以反映水系的区域岩性,物理化学风化特征。而对于控制河流离子化学自然因素的研究则有助于判别人类活动如农业灌溉施肥、矿山开采、工业生产等对河流的影响。同时,河流组分如NO3-、SO42-、As、Cd等的组成特征可以反映人类活动污染物输入程度。因此,河流水化学特征可以从一定程度上反映人类活动对水环境的影响。同时,研究河水离子化学特征及其分布规律也可以获得化学元素的生物地球化学循环、风化侵蚀及其在陆地—河流—海洋系统循环过程中的重要信息。此外,还有助于评价不同经济因素如人口密度等对河流离子的影响;有助于合理有效的利用河水的自净容量和环境效应,保护水资源;为水资源的开发利用、污染控制提供科学依据。   本文以中国南北方代表性流域—西江流域、长江中游(主要为汉水和乌江水系)、淮河上游及黄河下游流域河水为研究对象,通过对河水主要及微量金属离子的考察,结合基本水质理化参数,初步研究了我国南北方一些河流的离子化学特征及影响因素。通过此次研究,得出以下几点认识:   1. 西江流域河流pH均值为7.40,长江中游为8.11,黄河下游为8.34,淮河上游为7.95。西江流域河流DO含量均值为7.51 mg/l,低于黄河下游干流的8.27 mg/l;黄河下游支流DO含量显著低于干流。西江流域TDS经向分异显著,随经度增加逐渐降低。西江流域TDS平均值为152.78 mg/l,低于长江、黄河水系。   2. 西江流域、长江中游、淮河上游及黄河下游阴离子均以HCO3-平为主,各水系阴离子平均含量顺序均为HCO3- > SO42 -> Cl- > NO3-。研究区域水系中HCO3-平均含量以淮河上游为最高,西江流域最低;SO42 -、Cl-及NO3-平均含量则以黄河下游为最高,长江中游最低。研究区域水系阳离子均以Ca2+为主,西江流域及长江中游阳离子平均含量顺序为Ca2+ > Mg2+ > Na+ > K+,而淮河上游、黄河下游阳离子平均含量顺序则为Ca2+ > Na+ > Mg2+ > K+。   从长江中游到淮河上游、黄河下游,区域岩石风化是控制离子组成的主要因素,但蒸发结晶因素的贡献逐渐加强。其中,介于长江和黄河流域之间的淮河上游水系离子组成的过渡特征显著。研究区域水系中NO3-主要源于污染物排放,黄河干流污染较西江干流污染重。   3. 西江流域河流溶解态微量金属平均含量Zn>Cr>Cu>As>Al>Pb>Cd,其中Zn平均含量为37.72μg/l,Cd平均含量则仅为0.24μg/l。长江中游溶解态微量金属平均含量Zn>Cr>Pb>As>Cu=Al>Cd。淮河上游溶解态微量金属平均含量Zn>Cr>As>Pb>Al>Cu>Cd。黄河下游溶解态微量金属平均含量Zn>Cr>Cu>As >Al>Pb>Cd。研究区域河流中,西江流域溶解态Cu、Cr的平均含量分别为6.12μg/l和7.61μg/l,高于长江中游、淮河上游及黄河下游。长江中游溶解态Pb和Cd平均含量则高于西江流域、淮河上游及黄河下游。而研究区域中,黄河下游溶解态Al含量最高,达12.7 μg/l,淮河流域则体现出了Zn和Al的高含量特征。   化学风化过程在一定程度上导致了水体与风化壳之间不同化学元素的分异,使河水中溶解态Al和As相对于其它微量金属元素强烈富集,而Pb、Zn、Cu及Cr则相对亏损。河流溶解态As和Al除来源于矿物岩石风化外,也受外源输入—人类活动的影响。   4. 自然条件的区域差异是形成河流离子化学分异的主要因素,但人类活动对其影响逐步加深。工农业污染物输入在一定程度上改变了天然河流的离子化学组成,使河流组分NO3-、SO42-、As、Al等呈现富集趋势。化学元素在河流这一循环过程中间体中的地球化学行为越来越多地受人类活动影响。

Relevância:

60.00% 60.00%

Publicador:

Resumo:

As a continuation of previous research on the naturalization of non-native vascular plants in the Iberian Peninsula new chorological data are presented for 16 xenophytes recorded between 2010 and 2014, mostly in the provinces of Huelva and Barcelona (Spain) and in the Algarve and Estremadura (Portugal). For each taxon details about distribution, habitats occupied, previous records, degree of naturalization, etc. are provided. Lachenalia bulbifera and Cyperus albostriatus are probably reported for the first time in the wild in Europe, as are Gamochaeta filaginea, and Dysphania anthelmintica and Oenothera lindheimeri for Portugal and Spain respectively. Cosmos bipinnatus is cited as a novelty for the Algarve (Portugal). Newly reported or confirmed for the province of Huelva are: Amaranthus hypochondriacus, Epilobium brachycarpum, Nephrolepis cordifolia, Ficus microcarpa, Tamarix parviflora and Tamarix ramosissima, while Atriplex semibaccata, Chloris truncata, and Elymus elongatus subsp. ponticus are new for Barcelona. Finally, Passiflora caerulea is a novelty for both Barcelona and Huelva provinces.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Resumen tomado de la publicaci??n