中国天山过去43年大气环境变化：来自冰芯草酸根记录的证据

中、低纬度地区山地冰川有机酸记录的研究是目前国际冰芯地球化学研究的前沿之一。中国天山乌鲁木齐河源一号冰川为一中纬度山地冰川。对其冰芯的草酸根含量的分析显示，其冰芯所记录的过去43年草酸根变化的总体特征是在一个背景值基础上存在着含量的突变峰值。草酸根的背景值含量在1ng／g左右，在部分冰芯段，其含量甚至低于测试分析的检测限；而大多数草酸根峰值的含量都达到或超过了10ng／g。草酸根的平均含量为3．6±9．2ng／g(x^-±1σ，N=534)，其中70％以上由峰值构成。50年代后期是草酸根的一个低值期，平均含量略高于本底值；至60-70年代达到最高值，平均含量为5．0ng／g；80年代草酸根平均含量又下降到接近50年代后期的水平；至90年代回落到本底值附近。草酸根的主要来源是人类活动对大气所造成的污染。其过去43年平均含量的变化大致与中国西部工业和环境保护事业的发展历程相一致，是西部区域大气污染变化的一种反应。

生态转换系统中土壤有机质变化的稳定碳同位素示踪研究进展

因光合作用的途径不同，C3植物与C4植物具明显的δ13C值差异，根据这种特性，在生态系统发生转变的地域，可较好地将稳定碳同位素方法应用于土壤有机质研究中，本文对此类方法及研究现状作了较综合的论述。

铊的土壤污染及其环境影响

铊是典型的毒害金属元素。土壤铊主要有自然风化和人为排放两大来源。世界范围内，铊在土壤中的含量为0．2～1．0mg/kg。贵州黔西南滥木厂铊矿化区土壤中的铊十分富集。土壤中铊的生物有效性形态特征的研究表明，土壤中浓HNO3可提取铊的“环境不稳定相态”含量14～124mg/kg，占土壤中铊的环境总量(21～282mg/kg)的60％～70％，而NH4Ac提取的可交换相态含量较低，为0．6～4．8mg/kg，仅为“环境不稳定相态”含量的1％～4％，水溶相态含量则更低，为0．01～0．22mg/kg。土壤铊具有被植物体优先吸收富集的特性。铊在甘蓝卷心菜中的含量高达120～495mg/kg(DW)，其吸收富集系数为1～10．7。因而，铊是一个易从污染土壤迁移至食物链中不可忽视的有毒元素.

地幔柱与岩浆成矿-峨嵋山大火成岩省地震波速层物相解释及典型PGE矿床成岩成矿机制研究

地幔柱概念在19世纪60至70年代就被提出，但是由于板块构造理论在解释地球上岩浆活动的分布规律时取得了空前的成功，在当时这一理论是被排斥的。板块边界概念可以解释地球上绝大部分的岩浆产出，但在解释板内岩浆的成因时往往显得力不从心，尽管这些岩浆的体积只占地球岩浆总量的2％。地幔柱理论模型发展到现在得到不同学科的支持。地质学、地球化学、地球物理学、古生物学、比较行星学、实验岩石学等等都提供了直接或间接的证据，证明地幔柱几乎存在整个地：质历史时期。当前地幔柱理论中在地球化学领域有两大研究热点：高钦低钦玄武岩的起源以及地幔柱中是否存在循环俯冲洋壳物质。完全解决这些问题才可能深入系统地建立地慢柱成矿作用模型。现在已经建立了一些矿床类型与地慢柱作用的联系：如现在认为赋存在金伯利岩中的金刚石矿床的形成与地慢柱作用密不可分，一些岩浆硫化物矿床和岩浆氧化物矿床很显然是地慢柱岩浆作用形成的，如西伯利亚火成岩省的Noril'sk-Talnakh铜镍铂族元素矿床以及KeweenawaJI大陆裂谷体系的Dultlth杂岩体的Cu-Ni矿床。另外还有赋存在大型基性一超基性层状岩体中的PGE、Ni和cu矿床，如Great Dyke和布什维尔德杂岩体。一些超大型热液矿床也与地慢柱有可能的联系（Pirajno，2000）：如270oMa形成的超大型Kidd Creek火山成因块状硫化物矿床（Bleeker et al.，1 999；Wynan et al.，1999）和南澳大利亚1600Ma形成的超大型olymPicD翻矿床。本文的研究工作包含两方面内容：通过热力学计算峨眉山玄武岩在深部的结晶分异，对峨眉山大火成岩省的岩浆量分布和岩浆氧化物矿床（华Ti磁铁矿矿床）的分布以及下地壳高波速层的物相进行理论解释；对峨眉山大火成岩省金宝山PGE典型矿床进行成岩成矿的地球化学研究，预测整个大火成岩省的岩浆硫化物矿床产出位置。大多数峨眉山玄武岩的 MgO＜7％，Ni为4-232ppm，它们是原始岩浆结晶分异后的产物。峨眉山玄武岩省下地壳和上地幔之间存在厚度为：8-25km1，P彼速为7.1-7.8km／s的附加层（高地震波速层）。滇西地区出露的洲套第三纪富碱斑岩，地球化学和同位素研究表明斑岩的岩浆源是来自“壳一慢混合层”，源区的形成时代为220-25Ma，与峨眉山玄武岩的形成时代一致。所以有理由认为该附加层是由峨眉山玄武岩在此结晶分异形成的。与地慢柱有关的洋岛Hawaii、Marquesas Islands；海底高原Oniong Java、大陆火山岩省ColumbiaRiver Plateaus地震彼研究都表明在上地慢顶部有一高速附加层，Farnetani etal.（1996）的研歼表明高速附加层是由来自地幔柱的岩浆在此结晶分异形成的。玄武岩是一种混合的部分熔融产物，是不同成分的地幔橄榄岩在不同的压力下熔出的。这种降压熔融高温高压实验是做不到的。熔出的熔体成分是温度、压力及橄榄岩成分（源区）的函数，形成的岩浆是一个多压熔融的集合体。热力学计算能够较为精确地计算出生成的岩浆成分和约束岩浆产生的过程。岩浆的结晶分异也是同样的情形，尤其是分离结晶过程，实验岩石学是很精确难模拟其过程的。热力学计算使用的MELTS程序，MELTS适用范围很广，适用于模拟岩石熔融生成岩浆和岩浆的冷却结晶。现今峨眉山大火成岩省的地壳厚度为40恤，这被认为是后期褶皱加厚的缘故。根据峨眉山玄武岩中辉石斑晶成分和玄武岩本身成分计算出分异结晶的压力为6kb，那么当时的地壳厚度约为20km：选择氧逸度为QFM，这一氧逸度范围认为是大多数大陆溢流玄武岩结晶分异时的氧化还原环境。热力学计算结果通过峨眉山玄武岩成分进行约束和验证。Al2O3、NaZO＋K 20、CaO与MgO计算的演化趋势线与实际观察的演化符合较好，橄榄石和斜方辉石的结晶使得CaO随着MgO的降低而增高；当单斜辉石成为液相线矿物时，cao也随着Mgo的降低而降低了。单斜辉石在岩浆演化到MgO＝10．3％时成为液相线矿物。整个计算过程中斜长石未成为液相线矿物，这与大多数玄武岩不具有Eu异常是一致的，并月＿Al2O3随着MgO的减小单调增加也说明了这点。不过大多数峨眉山玄武岩常含有斜长石斑晶，这是低压下结晶分异的结果。由于斜长石密度小，所有很难与高铁玄武岩分离。整个计算的难点也是创新点是波速计算。通过分离的堆晶矿物组合中各种矿物的成分和质量分数计算的附加层波速比观察值高，不过堆积岩体常常会有残留岩浆存在矿物晶粒间，这样会降低岩石的压缩波速。大型基性一超基性岩体常常会残留有或者捕获5-30％的岩浆。假定两个高波速附加层分别捕获7叭，和巧％的残留岩浆，计算的结果就大体等于观察值。热力学和质量平衡计算研究表明：高地震波速层为橄榄辉石岩一辉石岩的巨型侵入岩体；峨眉山中岩区的岩浆量最大也符合含V-Ti磁铁矿矿床只产在中岩区，如太和、白马、攀枝花、红格等岩体；西岩区的岩浆量最小表明几乎没有可能在西岩区形成有规模的V-Ti磁铁矿矿床，实际观察仅仅只见到数量少而小的岩体；东岩区下地壳厚达20灿1的高波速层暗示东岩区上地壳的侵入岩体积也应该具有相当规模，应该是V－Ti磁铁矿矿床成矿区。目前在东岩区很少发现与峨眉山玄武岩有关的岩浆矿床的主要原因是：东岩区的剥蚀深度不够，没有可观的侵入岩体出露，而中岩区侵入岩都侵入在元古代地层中。按照质量平衡的计算方法，最保守的估算整个峨眉地慢柱岩浆事件产生的岩浆量为8.9*106km3，上地壳峨眉山玄武岩和侵入岩体积为3.9*106km3。如果按照初始覆盖面积5x106km2计算（与西伯利亚暗色岩初始覆盖面积相当），喷发高峰期为2Ma，计算的喷发速率为3.9km3／year。这并不亚于西伯利亚暗色岩的喷发速率4km3／year。这对于研究峨眉山大火成岩浆事件与二叠·三叠交界或end-QuadaluPian生物灭绝之间的可能联系具有重要意义。本文另一方面的研究工作是：首先系统地介绍了岩浆硫化物矿床的基本原理，然后通过金宝山PGE矿床实例研究，提出金宝山岩体成岩模式，并且对整个峨眉山大火成岩省的岩浆硫化物矿床产出位置进行理论预测。详细地球化学研究表明金宝山镁铁一超镁铁岩是峨眉山大火成岩省古老火山岩浆房的残留物。岩体主要由底部超镁铁岩和上部镁铁岩组成，两种岩石的质量大致相同。根据超镁铁岩的矿物组合计算的成岩时的氧逸度较高，热力学方法计算的成岩压力为2kb左右。超镁铁岩的包嵌结构和铁铁岩的微晶一细晶结构说明超镁铁岩为镁铁岩结晶的矿物堆积形成的。镁铁一超镁铁岩的蚀变程度不同以及Sc、Sr、Eu等元素在两类岩石中的不同特征指示了整个成岩过程。金宝山岩体的原始岩浆 MgO=8％说明高镁玄武岩并不是形成PGE矿床的必要条件。金宝山的成岩模式是：在火山喷发前，岩浆侵位时橄榄石和少量铬尖晶石先结晶，沉淀在岩浆房底部；随后结晶的是斜方辉石和斜长石，斜方辉石也沉淀在岩浆房底部，斜长石由于密度较小集中中岩浆房上部，岩浆房的中部是：少量的斜长石小斑晶。由于斜方辉石和斜长石的结晶，这样岩浆中的Sc、Sr和Eu就会亏损，也是岩浆房底部堆积岩的原始捕获岩浆。火山喷发后，由于压力的突然降低，岩浆房底部的堆晶会发生再熔融，几乎消耗掉所有的斜方辉石，橄榄石也呈熔蚀状浑圆形态，重新熔融的斜方辉石导致超镁铁岩中残留岩浆比原始捕获岩浆更加富Sc，这种岩浆由于富MgO和在快速冷却的环境下同时结晶，最终形成光性方位一致的单刹辉石。喷发后岩浆房空间的剩余导致围岩-灰岩进入，造成岩浆房中剩余岩浆强烈的碳酸盐化。峨眉山玄武岩Cr-Mg#的相关关系定义一条正常玄武岩演化线。大多数这些玄武岩的Ni也保持了这种演化关系，其中低钦玄武岩和过渡型高钦玄武岩Ni-Mg＃相关关系远离了正常演化线，这些玄武岩的Cu-Mg#相关关系也有类似的情形。峨眉山低钦和过渡类型高钦玄武岩Ni和 Cu的非正常亏损，表明它们在地表下经历了硫饱和事件。金宝山岩浆硫化物矿床成岩模型的建立，为在整个大火成岩省寻找岩浆硫化物矿床提供了一种新认识。低钦和过渡型高钦玄武岩的古老火山口下部是岩浆硫化物矿床的所在地。

表生条件下铊矿物的氧化溶解动力学及其反应性迁移实验研究

贵州省兴仁县滥木厂铭矿床是世界上唯一的铭的独立矿床。多年来，由于对蛇矿产资源的开发，大量未及时提取和利用的含佗矿石堆积于地表，经过风化淋滤作用，进入当地的水源和土壤，并通过食物链进入人体。20世纪60-70年代，滥木厂地区有近1000名村民患有不同程度的铂中毒，轻者脱发、视力减退，重者失明、丧失劳动力，至今在该地区仍可见到铭中毒患者。该区成为世界上唯一爆发过大规模馆中毒的病发区。馆又是人体的非必需元素，体内任何含量的馆都会对人体造成危害。饮用水的安全标准中，铭的含量不得超过1μg／L。因此对表生条件下，含铂矿物的氧化溶解动力学以及反应性迁移的实验研究具有重要的现实意义。通过对滥木厂铭矿床中的主要含铭矿物（红铭矿）在酸性矿水条件下的氧化溶解过程、光照旧光照射和汞弧灯照射）对铭价态改变的影响，以及酸性矿水条件下铁对蛇吸附的实验研究，得到如下几点认识：1．红铭矿的氧化溶解动力学实验表明：红铂矿的氧化溶解速率受到温度、氧化剂中阴离子种类及氧化剂浓度的影响。随着温度的升高，红蛇矿的氧化速率增高；Cl-离子的存在更有助于红锭矿的氧化溶解，表现为氧化溶解速率的增高；随着氧化剂浓度的升高，红铭矿的氧化速率逐渐降低，这主要是由于高铁浓度下，红佗矿表面形成了一层厚约2nm的铁硫化合物的膜，减缓了红铭矿进一步溶解。红铭矿表面形态和成分的电镜分析表明，红铭矿表面具有较多的活性点，因此含铭矿石在初露地表时对环境的污染比较强烈，经过风化淋滤作用后，红铭矿表面的活性点减少，加之硫铁化合物膜的形成，阻止了其对环境的进一步污染。但这并不排除一旦环境介质改变，红铭矿表面氧化形成的膜被破坏，红铭矿的新鲜表面暴露出来，活性点增多，溶解性加强，继续对周围环境造成强烈的污染。从红蛇矿24小时溶解的总馆量来看，酸性矿水条件下红佗矿的氧化溶解是贵州省兴仁县滥木厂地区佗污染的一个重要来源。2．铭的光致氧化实验结果表明：无论日光还是汞弧灯照射，水溶液中的T1（I）均可被氧化成T1（III）。州值越低、光照强度越大，铭的光氧化速率越快，UVB区的紫外光对铭的光氧化起着主要作用，微生物作用在本实验条件下，相对于光氧化作用并不明显。3．铁对铭的吸附实验表明：铁的水合氧化物对水溶液中铭的吸附除受溶液的pH值和吸附剂的阴离子种类的影响外，主要与佗的价态有直接关系。铁的水合氧化物对Tl（I）具有一定的吸附能力，阴离子种类对T1（I）吸附的作用稍有差别，C1-离子存在时，铁对Tl（I）的吸附更强一些吸附率达到50％左右，而S叮一离子存在条件下，铁对Tl（I）的吸附率小于20％。碱性（pH＝10左右）条件下，铁对T1（I）的吸附较中胜条件更明显一些。T1（III）由于自身的水解作用很强，在不同pH值和不同阴离子存在条件下，与Fe（III）均可发生共沉淀作用而被完全从水溶液中脱除。利用光照将Tl（I）氧化成Tl（III），再利用T1（III）易被沉淀或共沉淀吸附的特性，将Tl以Tl（OH）3，的形式吸附固定下来，降低了铭的活动性，进而可以减少铭对环境的影响，为锭污染的环境治理提供了重要的理论依据。

Prevalência de sinais e sintomas de Disfunções Temporomandibulares em pacientes que se dirigem à consulta de Otorrinolaringologia

Projeto de Pós-Graduação/Dissertação apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Mestre em Medicina Dentária

Rationale and design of the Exercise Intensity Trial (EXCITE): A randomized trial comparing the effects of moderate versus moderate to high-intensity aerobic training in women with operable breast cancer.

BACKGROUND: The Exercise Intensity Trial (EXcITe) is a randomized trial to compare the efficacy of supervised moderate-intensity aerobic training to moderate to high-intensity aerobic training, relative to attention control, on aerobic capacity, physiologic mechanisms, patient-reported outcomes, and biomarkers in women with operable breast cancer following the completion of definitive adjuvant therapy. METHODS/DESIGN: Using a single-center, randomized design, 174 postmenopausal women (58 patients/study arm) with histologically confirmed, operable breast cancer presenting to Duke University Medical Center (DUMC) will be enrolled in this trial following completion of primary therapy (including surgery, radiation therapy, and chemotherapy). After baseline assessments, eligible participants will be randomized to one of two supervised aerobic training interventions (moderate-intensity or moderate/high-intensity aerobic training) or an attention-control group (progressive stretching). The aerobic training interventions will include 150 mins.wk⁻¹ of supervised treadmill walking per week at an intensity of 60%-70% (moderate-intensity) or 60% to 100% (moderate to high-intensity) of the individually determined peak oxygen consumption (VO₂peak) between 20-45 minutes/session for 16 weeks. The progressive stretching program will be consistent with the exercise interventions in terms of program length (16 weeks), social interaction (participants will receive one-on-one instruction), and duration (20-45 mins/session). The primary study endpoint is VO₂peak, as measured by an incremental cardiopulmonary exercise test. Secondary endpoints include physiologic determinants that govern VO₂peak, patient-reported outcomes, and biomarkers associated with breast cancer recurrence/mortality. All endpoints will be assessed at baseline and after the intervention (16 weeks). DISCUSSION: EXCITE is designed to investigate the intensity of aerobic training required to induce optimal improvements in VO₂peak and other pertinent outcomes in women who have completed definitive adjuvant therapy for operable breast cancer. Overall, this trial will inform and refine exercise guidelines to optimize recovery in breast and other cancer survivors following the completion of primary cytotoxic therapy. TRIAL REGISTRATION: NCT01186367.

Assessment of the origin and stability of Nifedipine polymorph IV by differential scanning calorimetry (DSC)

Purpose. To examine the thermal transition(s) between different polymorphic forms of Nifedipine and to define experimental conditions that lead to the generation of polymorph IV. Methods. Experiments were performed using a DSC 823e (Mettler Toledo). Nifedipine exists in four polymorphic forms, as well as an amorphous state. Examination of Nifedipine was conducted using the following method(s): cycle 1: 25ºC to 190ºC, 190ºC to 25ºC (formation of amorphous Nifedipine); cycle 2: 25ºC to X (60,70,80...150ºC), X to 25ºC; cycle 3: 25ºC to 190ºC and holding isothermally for 5 min between cycles (heating/cooling rate of 10ºC/min). Results. The amorphous state Nifedipine can sustain heating up to 90ºC without significant changes in its composition. Cycle 2 of amorphous material heated up to 90ºC shows only the glass transition at ~44ºC. In cycle 3 of the same material, a glass transition has been recorded at ~44ºC, followed by two exotherms (~100 and ~115ºC (crystallisation of polymorph III and II, respectively) and an endotherm (169ºC (melting of polymorphs I/II)). Samples that have been heated to temperatures between 100ºC and 120ºC in the second cycle showed a glass transition at ~44ºC and an additional exotherm at ~95ºC (crystallisation of polymorph III) on cooling a exotherm was observed at ~40ºC (crystallisation of polymorph IV). The same material showed no glass transition in cycle 3 but an endotherm at around 62ºC (melting of polymorph IV) an exotherm (~98ºC) and an endotherm (169ºC) melting of polymorph I/II. Heating the sample to a temperatures greater than 130ºC in cycle two results in a glass transition at ~44ºC, and two exotherms at ~102 and 125ºC (crystallisation of polymorphs III and I, respectively). Conclusions. DSC data suggests that polymorph IV can only be produced from amorphous or polymorph III samples. The presence of polymorph I or II drives the conversion of the less stable polymorphic form IV into the most stable form, I. Although form IV of Nifedipine can easily be created, following defined experimental conditions, it may only coexist with amorphous or polymorph III states. When polymorphs I and II are present in the sample polymorph IV cannot be etected.

Contributions to the bryological flora of the tropical and subtropical forests from the Argentina (Bryophyta, Musci).

The authors present here a list of 32 mosses belonging to 15 families: Brachytheciaceae, Cryphaeaceae, Entodontaceae, Hedwigiaceae, Hypnaceae, Leptodontaceae, Meteoriaceae, Neckeraceae, Pilotrichaceae, Polytrichaceae, Pterobryaceae, Racopilaceae, Rigodiaceae, Stereophyllaceae, and Trachypodaceae, all collected in the mountainous forests of the Yungas of the NW of the Argentina (Jujuy, Salta, Catamarca and Tucumán provinces), and also in the rainforests from the NE of the country (Misiones province). Eight species: Atrichum polycarpum, Chrysohypnum elegantulum, Pilosium chlorophyllum, Pilotrichella flexilis, Porotrichodendron lindigii, Pseudotrachypus martinicensis, Steerecleus scariosus, and Thamnobryum fasciculatum are new records for the bryologic flora from Argentina. Braunia imberbis and Squamidium brasiliense are two new records for the bryophytic flora of the Catamarca province; Porotrichodendron superbum is new for the Salta province, while Forsstroemia coronata is the first record for the Catamarca and Jujuy provinces. Aerolindigia capillacea, Braunia reflexifolia, Chryso-hypnum diminutivum, Meteorium deppei and Meteoridium remotifolium are five new citations for the Jujuy province, and Schoenobryum concavifolium is new for the bryophytic flora of the Misiones province. Many studied species occur more frequently in the Yungas than in the NE rainforests; others show separated distribution but live in both areas, the Yungas and Paranaense area, and others are more or less restricted to the Paranaense rainforest of the NE of Argentina. The taxonomy of species is updated, and comments are included on bibliographical precedents, ecology and chorology of each taxon.

Sub-Arctic populations of European lobster (Homarus gammarus) in Northern Norway.

The European lobster is distributed throughout the south and western regions of the Norwegian coast. A previous lobster allozyme investigation (1993) in the Tysfjord region, north of the Arctic Circle demonstrated that the lobster population from this region was genetically different from lobster samples collected in other parts of Norway. More detailed investigation including supplementary extensive sampling and additional allozyme, microsatellite and mtDNA analyses are reported here. This investigation supports the genetic distinctness of the Tysfjord population and shows that this is mainly due to a reduction (60�70%) in gene diversity (observed heterozygosities and number of alleles) compared with lobsters from more southern regions. In addition to the Tysfjord region, the comprehensive sampling also included lobsters found in the adjacent Nordfolda fjord system. Genetic analyses provided evidence for significant differences between the lobster populations of Tysfjord and Nordfolda, even though they are separated by a coastal distance of only 142 km. The two populations were also different with regards to several biological characteristics such as body size. The genetic difference between these two geographically close populations is likely to be due to the local hydrological conditions, preventing larval dispersal between the fjord systems. Assessment of lobster abundance in the north-west region suggests that the sub-arctic lobster populations are geographically isolated.

Persistently raised C-reactive protein levels are associated with advanced periodontal disease

Objective: The aim was to investigate whether there was an association between periodontitis or tooth loss in a homogeneous group of 60-70-year-old Western European men and either a sustained high or low level of C-reactive protein (CRP).
Material and Methods: Men enrolled in a cohort study of cardiovascular disease in Northern Ireland were screened in 1990-1994 and rescreened in 2001-2004, when a periodontal examination was completed. High-sensitivity CRP was measured from fasting blood samples. There were 806 men with six or more teeth who had either a high level (>3 mg/l) or a lower level of CRP at both time points. Multivariate analysis was carried out using logistic regression with adjustment for possible confounders. Models were constructed with the CRP level as the outcome variable and various measures of periodontal status (low and high threshold periodontitis) or tooth loss as predictor variables. Confounders included in the analysis were known cardiovascular risk factors of age, smoking, diabetes, BMI and socioeconomic status.
Results: There were 67 men who had a high value of CRP (>3 mg/l) and 739 men who had a CRP value =3 mg/l at both time points. The unadjusted odds ratio (OR) for advanced periodontitis to be associated with high CRP was 3.62, p=0.0003. The association was somewhat attenuated but remained significant (OR=2.49, p=0.02) after adjustment for confounders. A high level of tooth loss was also associated with high CRP with an adjusted OR of 2.17, p=0.008. Low threshold periodontitis was not associated with the level of CRP.
Conclusion: There was an association between advanced periodontitis and elevated CRP levels as measured at two time points at a 10-year interval in the 60-70-year-old European males investigated. This association was adjusted for various cardiovascular risk factors. There was also an association between high levels of tooth loss and high CRP in the men studied.

La ciudad de Rávena y los paisajes de la abstracción en "Deserto Rosso" de Michelangelo Antonioni

La presente investigación trata de poner énfasis en la importancia del paisaje en Deserto Rosso de Michelangelo Antonioni, erigiéndose este como elemento fundamental de la trama argumental del filme. Partiendo de esta premisa, se analiza el significado de dicho paisaje en el contexto socioartístico de los años 60. La interacción del hombre con su entorno parece ser el punto de partida para una reflexión más profunda sobre el devenir humano. Las nuevas conquistas estéticas alcanzadas y el análisis históricoartístico de los precedentes más inmediatos del filme, sitúan a Deserto Rosso como obra cumbre de la neovanguardia posmoderna europea.

A Low Complexity Real-time MIMO-Preprocessing For Fixed Complexity Sphere Decoder

Modern Multiple-Input Multiple-Output (MIMO) communication systems place huge demands on embedded processing resources in terms of throughput, latency and resource utilization. State-of-the-art MIMO detector algorithms, such as Fixed-Complexity Sphere Decoding (FSD), rely on efficient channel preprocessing involving numerous calculations of the pseudo-inverse of the channel matrix by QR Decomposition (QRD) and ordering. These highly complicated operations can quickly become the critical prerequisite for real-time MIMO detection, exaggerated as the number of antennas in a MIMO detector increases. This paper describes a sorted QR decomposition (SQRD) algorithm extended for FSD, which significantly reduces the complexity and latency
of this preprocessing step and increases the throughput of MIMO detection. It merges the calculations of the QRD and ordering operations to avoid multiple iterations of QRD. Specifically, it shows that SQRD reduces the computational complexity by over 60-70% when compared to conventional
MIMO preprocessing algorithms. In 4x4 to 7x7 MIMO cases, the approach suffers merely 0.16-0.2 dB reduction in Bit Error Rate (BER) performance.