贵阳近效水稻田甲烷的释放通量及其碳同位素组成的研究

全球环境问题越来越引起人们的关注，其中的温室效应气体是最引人注目的环境问题之一。近年来，大气中温效应气体的增多导致全球气候的变化。甲烷作为一种重要的温室效应气体，在大气中的浓度也连续增加。据观测，大气中甲烷浓度的年增长率为1%。甲烷不仅是一种重要的温室效应气体，而且还是一种重要的化学活性成分，它在大气中的化学过程影响了大气化学的成分。由于甲烷的重要作用，研究大气甲烷的来源及增加的原因成了学术界十分热门的领域，尤其是识别大气甲烷的来源和人力活动的释放显得更为有意义。水稻田释放的甲烷是大气甲烷的重要来源之一。目前，对水稻田释放的甲烷虽进行了许多研究，然而都是个别的、不连续的观测，根据这些数据估计全球水稻田释放甲烷总量的可靠性差，尤其是象我国这样一个水稻种植大国（水稻种植面积占全球水稻面积的22%），才刚刚开始对这一领域进行研究。因此，为了对我国水稻田释放的甲烷有一个较全面的认识以及为“八五”国家重大基础课题“中国环境未来演变趋势的研究”第三题奠定一些基础，本文于1991年水稻生长期间（6-9月）对贵阳近效水稻田释放的甲烷进行了研究，并且希望通过开展对甲烷稳定同位素的研究来识别甲烷的来源。利用透明有机玻璃为材料，自行设计了一套采样系统，收集的气体样品装于气袋内。而对甲烷碳同位素的测定，则尝试用化学方法在田间进行样品的处理，将稻田释放的甲烷直接转换成碳酸锶固体样品，以便于保存和运输。在整个实验过程中，共收集了160个样品，对甲烷释放率的日变化及季节变化进行了研究。甲烷释放率最高时达71.9mg/m~2.h，而最低只有3.0mg/m~2.h。平均释放率为15.6mg/m~2.h。在此期间，对10cm以下土壤温度、水温、大气温度和水稻生长情况作了记录，对土壤有机质含量和土壤质地进行了分析，试图揭示出水稻田甲烷释放的规律及影响水稻田甲烷释放的因素，并对所得出的结论作出进一步的讨论。经过研究发现，水稻田甲烷释放率在一日之内的变化有一定的规律。几次24小时的连续观测，都显示出一日之内甲烷释放率的最大值出现在凌晨或夜晚，而在正午阳光最强烈时甲烷释放率偏低。这一结果同文献报导的有一定偏差，可用甲烷的产生、输送和转化机制对这一现象定性地加以解释。稻田甲烷的排放率除了有日变化之外，还有明显的季节。在整个水稻生长期间，甲烷的释放率除了几天尺度的小波动外，还有三个明显的高甲烷排放期。第一个排放峰值出现在插秧后的分蘖期，即六月中旬，第二、第三个峰值分别出现在七月下旬和八月中旬。其中，第一个峰值最大，第三个峰值最小。当水稻种植需排水晒田时，甲烷释放率明显下降，复水后，甲烷释放率又增加。对稻田总有机碳和活性有机碳的分析揭示出，活性有机碳同甲烷的释放率之间有一定的相关关系。在活性有机碳含量高时，甲烷的释放率也越大，但总有机碳含量与甲烷释放率之间关系不明显。在水稻生长期间，甲烷释放率也显示出较大的日变化幅度。在排放峰值期间，日变化幅度最大，最高时达59.0mg/m~2.h，出现在第一排放峰值期间。收获前，日变化幅度最小，只有0.3mg/m~2.h。温度对甲烷释放率有一定的影响，在水稻生长期里，大气温度及土壤温度的变化趋势同甲烷释放率的季节变化比较一致。根据本文的测量结果，对贵州省水稻田的甲烷释放量进行了一个很粗略的估计，约为6.96 * 10~10克/年。在甲烷碳同位素组成的测定，本文采用化学方法对样品进行前处理，这种方法用于开展稳定同位素的工作是一种新的尝试。但由于缺乏经验，时间紧，只得到几个可供测试的样品，质谱的测定结果重现性不好，使得这一尝试的结果不令人满意。在测定甲烷碳同位素的同时，对土壤中有机质和空气的中CO_2的碳同位素也进行了测量，结果表明，土壤有机碳同位素较接近，为-20%左右，而空气CO_2由于光合作用与呼吸作用之故，白天和夜晚存在着差异，白天的δ~（13）C为-25%左右，夜晚δ~（13）C为-29%左右。通过建立一套系统和方法，对水稻田释放的甲烷进行了研究，对这一领域有一初步的认识，为今后系统地开展这一领域的研究奠定了基础。由于是初次开展地表生物源释放气体的研究，难免存在一些问题和不足，将在以后的更深入的研究中加以改进和提高。

非生物成因天然气的稳定同位素地球化学特征与判据

本采自松辽盆地的天然气进行了化学组分和氦、碳同位素分析。经空气校正后的氦同位素组成为 ~3He/~4He＝0.26 * 10~(-6)～7.48 * 10~(-6)，相应的幔源氦的贡献额为 2.3%～63%，显示了明显的幔源氦信息，表明松辽盆地天然气藏中有幔源挥发份加入。烃类气藏甲烷的灿位素组成为 δ~(13)C＝-53.3‰～-16.7‰，δ~(13)C小于-25‰ 的甲烷是生物成因的产物，δ~(13)大于-25‰的甲烷则可能是非生物成因的。甲烷及其同系物的碳同位素组成存在两类不同的分配模式。正序排列的分析模式，即 δ~(13)C_(CH_4) < δ~(13)C_(C_2H_6) < δ~(13)C_(C_3H_8) < δ~(13)C_(C_4H_(10))，表明了生物成因天然气的特征，而反序排列的分配模式，即 δ~(13)C_(CH_4) > δ~(13)C_(C_2H_6) > δ~(13)C_(C_3H_8) > δ~(13)C_(C_4H_(10))的存在则暗示了松辽盆地存在非生物成因的商业天然气藏。模拟原始太阳星云中地球吸积区条件进行了原始宇宙成因烃类的合成实验（费托反应）。对合成气进行了碳同位素组成分析，并结合反应机理讨论了费托反应中碳同位素的分馏和原始宇宙成因烃类的碳同位素分配模式。反应合成气中二氧化碳具有最重的碳同位素组成。甲烷及其同系物的碳同位素分配模式具有与生物成因烃类完全不同的反序排列特征，即 δ~(13)C_(CH_4) > δ~(13)C_(C_2H_6) > δ~(13)C_(C_3H_8) > δ~(13)C_(C_4H_(10))，这表明由原始宇宙成因烃类构成的非生物成因天然气中甲烷及其同系物的碳同位素分配的反序排列的。对非生物成因天然气的判识应依靠多项指标。作为灵敏的幔源挥发份示踪剂的氦同位素是非生物成因天然气有效的间接指示剂，甲烷及其同系物碳同位素的反序排列分配模式加上重的碳同位素组成可作为非生物成因天然气的可靠的内在指标。松辽盆地的区域构造特征，天然气中显著的幔源氦的存在，较重的甲烷同位素组成 (δ~(13)C_(CH_4) > -25‰)和甲烷及其同系物碳同位素的反序排列充分证明了松辽盆地存在非生物成因的商业天然气藏。

Large Decrease of Fluctuations for Supercooled Water in Hydrophobic Nanoconfinement

Using Monte Carlo simulations we study a coarse­grained model of a water layer confined in a fixed disordered matrix of hydrophobic nanoparticles at different particle concentrations c. For c = 0 we find a 1st order liquid­liquid phase transition (LLPT) ending in one critical point at low pressure P. For c > 0 our simulations are consistent with a LLPT line ending in two critical points at low and high pressure. For c = 25% at high P and low temperature T we find a dramatic decrease of compressibility, thermal expansion coefficient, and specific heat. Surprisingly, the effect is present also for c as low as 2.4%. We conclude that even a small presence of nanoscopic hydrophobes can drastically suppress thermodynamic fluctuations, making the detection of the LLPT more difficult.

Feeding and overwintering of Antarctic krill across its major habitats: The role of sea ice cover, water depth, and phytoplankton abundance

Antarctic krill (Euphausia superba) were sampled in contrasting habitats: a seasonally ice-covered deep ocean (Lazarev Sea), ice-free shelves at their northern range (South Georgia) and the Antarctic Peninsula (Bransfield Strait), and shelf and oceanic sites in the Scotia Sea. Across 92 stations, representing a year-round average, the food volume in krill stomachs comprised 71 +/- 29% algae, 17 +/- 21% protozoans, and 12 +/- 25% metazoans. Fatty acid trophic markers showed that copepods were consistently part of krill diet, not a switch food. In open waters, both diatom and copepod consumption increased with phytoplankton abundance. Under sea ice, ingestion of diatoms became rare, whereas feeding on copepods remained constant. During winter, larvae contained high but variable proportions of diatom markers, whereas in postlarvae the role of copepods increased with krill body length. Overwintering differed according to habitat. Krill from South Georgia had lower lipid stores than those from the Bransfield Strait or Lazarev Sea. Feeding effort was much reduced in Lazarev Sea krill, whereas most individuals from the Bransfield Strait and South Georgia contained phytoplankton and seabed detritus in their stomachs. Their retention of essential body reserves indicates that krill experienced most winter hardship in the Lazarev Sea, followed by South Georgia and then Bransfield Strait. This was reflected in the delayed development from juveniles to adults in the Lazarev Sea. Circumpolar comparisons of length frequencies suggest that krill growth conditions are more favorable in the southwest Atlantic than in the Lazarev Sea or off East Antarctica because of longer phytoplankton bloom periods and rewarding access to benthic food.

The isolation and purification of tris-2,2'-bipyridine complexes of ruthenium(II) containing unsymmetrical ligands

Monomeric ruthenium(II) complexes [Ru(L)3]2+ containing unsymmetric bipyridine ligands [Where L = 5-methyl-2,2'-bipyridine (L1), 5-ethyl-2,2'-bipyridine (L2), 5-propyl-2,2'-bipyridine (L3), 5-(2-methylpropyl)-2,2'-bipyridine (L4), 5-(2,2-dimethylpropyl)-2,2'-bipyridine (L5) and 5-(carbomethoxy)-2,2'-bipyridine (L6)] have been studied and the meridional and facial isomers isolated by the use of cation-exchange column chromatography (SP Sephadex C-25) eluting with either sodium toluene-4-sulfonate or sodium hexanoate. The relative yield of the facial isomer was found to decrease with increasing steric bulk, preventing the isolation of fac-[Ru(L5)3]2+. The two isomeric forms were characterized by 1H NMR, with the complexes [Ru(L1-3)3]2+ demonstrating an unusually large coupling between the H6 and H4 protons. Crystals suitable for X-ray structural analysis of [Ru(L1)3]2+ were obtained as a mixture of the meridional and facial isomers, indicating that separation of this isomeric mixture could not be achieved by fractional crystallisation. The optical isomers of the complex [Ru(L3)3]2+ were chromatographically separated on SP Sephadex C-25 relying upon the inherent chirality of the support. It is apparent that chiral interactions can inhibit geometric isomer separation using this technique.

Relocation, reproduction and remaining alive in the orb-web spider

When mortality is high, animals run a risk if they wait to accumulate resources for improved reproduction so they may trade-off the time of reproduction with number and size of offspring. Animals may attempt to improve food acquisition by relocation, even in 'sit and wait' predators. We examine these factors in an isolated population of an orb-web spider Zygiella x-notata. The population was monitored for 200 days from first egg laying until all adults had died. Large females produced their first clutch earlier than did small females and there was a positive correlation between female size and the number and size of eggs produced. Many females, presumably without eggs, abandoned their web site and relocated their web position. This is presumed because female Zygiella typically guard their eggs. In total, c. 25% of females reproduced but those that relocated were less likely to do so, and if they did, they produced the clutch at a later date than those that remained. When the date of lay was controlled there was no effect of relocation on egg number but relocated females produced smaller eggs. The data are consistent with the idea that females in resource-poor sites are more likely to relocate. Relocation seems to be a gamble to find a more productive site but one that achieves only a late clutch of small eggs and few achieve that.

Teaching Art History to Design Students

Art History is often seen as a mandatory core course in the curricula of design programs but it is rarely tailored to the needs and goals of such programs. Instead, the traditional chronological organization of lecture topics, invariably beginning with the “Venus of Willendorf” (c. 25,000 BC) is presented in order to impart to the students a supposed holistic “big picture.” This essay outlines the re-structuring of a two-semester first-year faculty-wide introductory art history course, entitled “History of Art and Design,” in the Faculty of Fine Arts and Design at Izmir University of Economics, Izmir, Turkey. The course was re-configured from a conventional chronologically-presented (time-oriented) lecture series to a thematically presented (topic-oriented) lecture series more relevant to the students of the faculty – architecture, interior architecture, graphic design, industrial design, and fashion design students.

Long-chain haloalkanes are incorporated into fatty-acids by Rhodococcus rhodochrous NCIMB-13064

The fatty acid composition of the cellular lipids of Rhodococcus rhodochrous NCIMB 13064 grown on various long-chain haloalkanes has been investigated and the influence of halogen substituents, carbon chain length and the position of halogen substitution in the growth substrate explored. Of the total fatty acids present in cells grown on 1-chloro-, 1-bromo- and 1-iodohexadecane, 75, 90 and 81%, respectively, were substituted in the omega-position by the corresponding halogen but only 1% of the fatty acids present after growth on 1-fluorotetradecane were fluorinated in this position. The extent of the halofatty acid incorporation with different halogen substituents in the growth substrate appears to reflect the degree to which oxygenase attack is restricted to the non-halogenated end of the haloalkane. Studies of the fatty acid composition of cells after growth on a series of 1-chloroalkanes containing an even number of carbon atoms between C-10 and C-18 indicated chlorofatty acid incorporation from C-12 to C-18 substrates at levels ranging from 21% with C-12 to 75% with C-16. The chlorofatty acids formed by initial oxidation of the chloroalkane were chain-lengthened or chain-shortened by from two to eight carbon atoms, with accompanying desaturation in some instances. Substantial quantities of a methyl-branched C-19:0 chlorofatty acid were also present with several chloroalkane substrates, When the fatty acid composition of cells after growth on 1-bromoalkanes containing an odd number of carbon atoms between C-11 and C-17 was examined, the incorporation of bromofatty acids was observed with C-13, C-15 and C-17 substrates; a maximum of 76% was recorded for the C-15 bromoalkane. As with even chain-length chloroalkanes, both chain-lengthening and -shortening occurred predominantly via two-carbon units so that most bromoacids present possessed an odd number of carbon atoms, When 1-bromododecane or 2-bromododecane were substrates, overall incorporations of bromofatty acids into the lipid fraction were very similar, demonstrating that the position of halogen substitution in the haloalkane was not critical in determining the extent of incorporation of the haloacids into cellular lipids. The results of the study indicate a mechanism by which degradation products of chlorinated paraffins could enter the biological food chain.

A Recyclable Acidic Ionic Liquid Gel Catalyst for Dehydration: Comparison with an Analogous SILP Catalyst.

An acid-functionalized ionic liquid was entrapped within a silica gel to yield a recyclable liquid phase catalyst for the dehydration of rac-1-phenyl ethanol. Hot filtration tests showed that the activity was within the gel. Comparison with an analogous SILP system revealed fundamental differences in the properties and behavior of the materials.

Arsenate resistance in the ericoid mycorrhizal fungus Hymenoscyphus ericae

• Differential resistance to arsenate (AsO₄ ^3-) is demonstrated here among populations of the ericoid mycorrhizal fungus Hymenoscyphus ericae isolated from Calluna vulgaris in natural heathland soils and soils contaminated with AsO₄ ^3-. • Isolates (c. 25) of the fungus from each of two As and Cu mine sites, and a natural heathland site, were screened for AsO₄ ^3- and Cu²⁺ resistance by growing isolates in media containing a range of AsO₄ ^3- and Cu²⁺ concentrations. • H. ericae populations from the mine sites demonstrated resistance to AsO₄ ^3- compared with the heathland population; the mine-site populations producing significant growth at the highest AsO₄ ^3- concentration (4.67 mol m^-3), whereas growth of the heathland population was almost completely inhibited. EC₅₀ values for mine-site isolates were estimated to be 5-41-times higher than the heathland population. All isolates produced identical responses to increasing Cu²⁺ concentrations, with no differences observed between mine-site and heathland isolates. • Populations of H. ericae on the contaminated mine sites have developed adaptive resistance to AsO₄ ^3-. By contrast, Cu²⁺ resistance appears to be constitutive.

Effect of temperature and prey in the biology of Scymnus subvillosus (Goeze) (Coleoptera: Coccinellidae)

Dissertação de Mestrado, Biotecnologia em Controlo Biológico, 18 de Dezembro de 2013, Universidade dos Açores.

Valorização da Borra de Café: Otimização da Produção de Biodiesel por Catálise Enzimática

O decréscimo das reservas de petróleo e as consequências ambientais resultantes do recurso a combustíveis fósseis nos motores a diesel têm levado à procura de combustíveis alternativos. Esta pesquisa alicerçada nas fontes de energia renovável tornou-se essencial, face à crescente procura de energia e ao limitado fornecimento de combustíveis fósseis . Resíduos de óleo de cozinha, gordura animal, entre outros resíduos de origem biológica, tais como a borra de café, são exemplos de matérias-primas para a produção de biodiesel. A sua valorização tem interesse quer pela perspetiva ambiental, quer pela económica, pois aumenta não só a flexibilidade e diversificação das matérias-primas, mas também contribui para uma estabilidade de custos e alteração nas políticas agrícolas e de uso do solo. É neste contexto que se enquadra o biodiesel e a borra de café, pretendendo-se aqui efetuar o estudo da produção, à escala laboratorial, de biodiesel a partir da borra de café, por transesterificação enzimática, visando a procura das melhores condições reacionais. Iniciando-se com a caracterização da borra de café, foram avaliados antes e após a extração do óleo da borra de café, diversos parâmetros, de entre os quais se destacam: o teor de humidade (16,97% e 6,79%), teor de cinzas (1,91 e 1,57%), teor de azoto (1,71 e 2,30%), teor de proteínas (10,7 e 14,4%), teor de carbono (70,2 e 71,7%), teor de celulose bruta (14,77 e 18,48%), teor de lenhina (31,03% e 30,97%) e poder calorifico superior (19,5 MJ/kg e 19,9 MJ/kg). Sumariamente, constatou-se que os valores da maioria dos parâmetros não difere substancialmente dos valores encontrados na literatura, tendo sido evidenciado o potencial da utilização desta biomassa, como fonte calorifica para queima e geração de energia. Sendo a caracterização do óleo extraído da borra de café um dos objetivos antecedentes à produção do biodiesel, pretendeu-se avaliar os diferentes parâmetros mais significativos. No que diz respeito à caracterização do óleo extraído, distingue-se a sua viscosidade cinemática (38,04 mm2/s), densidade 0,9032 g/cm3, poder calorífico de 37,9 kcal/kg, índice de iodo igual a 63,0 gI2/ 100 g óleo, o teor de água do óleo foi de 0,15 %, o índice de acidez igual a 44,8 mg KOH/g óleo, ponto de inflamação superior a 120 ºC e teor em ácidos gordos de 82,8%. Inicialmente foram efetuados ensaios preliminares, a fim de selecionar a lipase (Lipase RMIM, TL 100L e CALB L) e álcool (metanol ou etanol puros) mais adequados à produção de biodiesel, pelo que o rendimento de 83,5% foi obtido através da transesterificação mediada pela lipase RMIM, utilizando como álcool o etanol. Sendo outro dos objetivos a otimização do processo de transesterificação enzimática, através de um desenho composto central a três variáveis (razão molar etanol: óleo, concentração de enzima e temperatura), recorrendo ao software JMP 8.0, determinou-se como melhores condições, uma razão molar etanol: óleo 5:1, adição de 4,5% (m/m) de enzima e uma temperatura de 45 ºC, que conduziram a um rendimento experimental equivalente a 96,7 % e teor de ésteres 87,6%. Nestas condições, o rendimento teórico foi de 99,98%. Procurou-se ainda estudar o efeito da adição de água ao etanol, isto é, o efeito da variação da concentração do etanol pela adição de água, para teores de etanol de 92%, 85% e 75%. Verificou-se que até 92% decorreu um aumento da transesterificação (97,2%) para um teor de ésteres de (92,2%), pelo que para teores superiores de água adicionada (75% e 85%) ocorreu um decréscimo no teor final em ésteres (77,2% e 89,9%) e no rendimento da reação (84,3% e 91,9%). Isto indica a ocorrência da reação de hidrólise em maior extensão, que leva ao desvio do equilíbrio no sentido contrário à reação de formação dos produtos, isto é, dos ésteres. Finalmente, relativamente aos custos associados ao processo de produção de biodiesel, foram estimados para o conjunto de 27 ensaios realizados neste trabalho, e que corresponderam a 767,4 g de biodiesel produzido, sendo o custo dos reagentes superior ao custo energético, de 156,16 € e 126,02 €, respetivamente. Naturalmente que não esperamos que, a nível industrial os custos sejam desta ordem de grandeza, tanto mais que há economia de escala e que as enzimas utilizadas no processo deveriam ser reutilizadas diversas vezes.

Ionic regulation in goldfish, Carassius auratus, acclimated to constant and diurnally-cycling temperature conditions

The effects of a diurnal sine-wave temperature cycle (250 +- 5° C) on the wa terI-e etc r o1 yt est a t us 0 f gol df1' Sh , Carassius auratus, was assessed through determination of Na+, K+, Mg2+, Ca2+, Cl- and water content in plasma, Red blood cells and muscle tissue. Animals were also acclimated to o 0 0 static temperatures (20 C, 25 c, 30 C) corresponding to the high, low and mid-ooint temperatures of the cycle. All groups were sampled at 03:00, 09:00, 15:00 and 21:00 hr. Hemoglobin content and packed cell volume, as well as electrolyte and 'water levels were determined for each animal and red cell ion concentrations and ion : hemoglobin ratios estimated. Cycled animals were distinct from those at constant temperatures in several respects. Hematological parameters were elevated above those of animals at constant temperature and were, on a diurnal basis, more stable. Red blood cell electrolyte levels varied in an adaptively appropriate fashion to cycle temperatures. This was not the case in the constant temperature groups_ Under the cycling regime, plasma ion levels were more diurnally stable than those of constant temperature fish. Although muscle parameters in cycled fish exhibited more fluctuation than was observed in plasma, these also tended to be relatively more stable than was the caseErythrocytic data are discussed in terms of their effects on hemoglobin-oxygen affinity while plasma and muscle observations were considered from the standpoint of overall water-electrolyte balance. In general, cycled fish appeared to be capable of stabilizing overall body fluid composition, while simultaneously effecting adaptively-appropriate modifications in the erythrocytic ionic microenvironment of hemoglobin. The sometimes marked diurnal variability of water-electrolyte status in animals held at constant temperature as opposed to the conservation of cycled fish suggests that this species is, in some fashion, programmed for regulation in a thermally-fluctuating environment. If this interpretation is valid and a phenomenon of general occurrence, some earlier studies involving constant acclimation of eurythermal species normally occupying habitats which vary in temperature on a daily basis may require reconsideration. at constant temperature.

La détention provisoire au Québec : portrait de l’évolution d’une mesure sur une décennie et de la population qui en est l’objet en 2011-2012

L’objectif de ce mémoire est de dresser un portrait de l’évolution du recours à la détention provisoire au Québec depuis 2002 jusqu’à 2012, pour ensuite préciser les caractéristiques des personnes prévenues en comparaison à celles détenues tel qu’elles se dessinent en 2012, pour la population générale en détention dans les institutions carcérales de juridiction provinciale au Québec, et pour les populations spécifiques que forment les femmes et les personnes autochtones en regard de leur proportion dans la population générale. Pour ce faire, les tendances actuelles en matière de recours à la détention provisoire sont établies et comparées à celle de 2002. Aussi, un portrait des personnes en détention provisoire au Québec en 2011-2012 est dressé à partir de certaines caractéristiques sociodémographiques et criminelles liées à la détention provisoire selon les écrits précédents sur la question. Ce portrait est comparé à celui des personnes incarcérées dans les mêmes institutions suite à une condamnation à une peine de prison de deux ans moins un jour ou moins. Par la suite, des analyses bivariées sont effectuées dans le but de comprendre la relation entre la détention provisoire et l’issue du processus pénal, qui consiste, dans la présente étude, à la condamnation à une sentence de détention ou une sentence autre des personnes admises en détention provisoire dans un premier temps. Des analyses de régression logistiques viennent préciser quelles variables permettent le plus clairement de prédire l’imposition d’une sentence de détention aux personnes prévenues dans les institutions carcérales provinciales, au Québec en 2012. Les résultats de nos analyses indiquent qu’il y a une surreprésentation des hommes et des Autochtones en détention provisoire au Québec. De plus, certaines caractéristiques sociodémographiques et criminelles se révèlent significativement liées à la condamnation à la détention comme le fait d’être un prévenu d’origine autochtone, de posséder des antécédents judiciaires, d’avoir commis un ou des délits de système et de faire partie d’un groupe criminel. Il s’agit du même coup de bons prédicteurs de l’imposition d’une sentence de prison suivant la détention provisoire. Lorsqu’un individu cumule ces caractéristiques, il fera face à une sentence d’incarcération dans le trois quarts des cas. Finalement, il apparaît que malgré la volonté exprimée de longue date et reprise à l’entrée en vigueur de la Loi C-25 de faire de la détention provisoire une mesure de dernier recours, le recours à cette mesure ne cesse de croître, alors même que la détention découlant d’une condamnation paraît diminuer, ce qui se traduit par un rapport de plus en plus disproportionné entre personnes prévenues et personnes condamnées au sein des prisons du Québec, le ratio jouant en défaveur des personnes prévenues.