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71.
Using the entire population of professors at universities in the province of Quebec (Canada), this article analyzes the relationship between sex and research funding, publication rates, and scientific impact. Since age is an important factor in research and the population pyramids of men and women are different, the role of age is also analyzed. The article shows that, after they have passed the age of about 38, women receive, on average, less funding for research than men, are generally less productive in terms of publications, and are at a slight disadvantage in terms of the scientific impact (measured by citations) of their publications. Various explanations for these differences are suggested, such as the more restricted collaboration networks of women, motherhood and the accompanying division of labour, women’s rank within the hierarchy of the scientific community and access to resources as well as their choice of research topics and level of specialization.  相似文献   
72.
The application of fixed operational protocols and settings for membrane bioreactors (MBR) often leads to suboptimal filtration conditions due to the dynamic nature of mixed liquor characteristics. With regard to process optimization and energy savings, the potential benefits of a dynamic control system, enabling to adapt fouling control actions (ACS outputs) in an automated way to the actual mixed liquor fouling propensity, are thus obvious. In this paper, the pilot-scale validation of such an advanced control system (ACS) is elaborated. A specific on-line fouling measurement method, the MBR-VFM (VITO Fouling Measurement), was used for the evaluation of the mixed liquor’s reversible fouling propensity, which was used as a primary ACS input parameter. A first series of tests with a gradual increase in complexity of the selected input and output parameters indicated the functionality of the ACS and demonstrated a substantial reduction of aeration, however sometimes at the expense of a higher fouling rate. The ACS was further fine-tuned and subsequently tested for a longer period under more dynamic operating conditions. A significant correlation was found between the reversible fouling potential measured by the MBR-VFM and the on-line permeability, indicating that the MBR-VFM is a suitable ACS input. Furthermore, an average 22% reduction in aeration flow to the membranes could be achieved without any obvious negative effect on filtration performance. This indicates that this approach is promising to optimize energy consumption in MBRs.  相似文献   
73.
74.
BACKGROUND: Accommodation-convergence spasm (spasm of the near reflex) is usually bilateral, resulting in increased myopia, convergence, and miosis. Unilateral spasm of accommodation has rarely been reported. PATIENTS: We investigated three females (age range 10-19 years) referred for investigations of retrobulbar optic neuritis (2 cases) and decompensated esophoria (1 case). RESULTS: They all presented unilateral spasm of accommodation with visual loss due to increased myopia (-3.5 to -11.75 diopters). Apart from that, results of neuro-ophthalmological examination were normal. CONCLUSIONS: Unilateral accommodation spasm is rare and can mimic retrobulbar optic neuritis and convergent strabismus. The three components of the accommodation-convergence spasm may not always be present simultaneously. Recognizing such an entity is important to prevent the patient from useless, costful and potentially harmful investigations.  相似文献   
75.
The effect of type 1 diabetes mellitus on hypoxia-induced coronary vasodilation was studied in isolated perfused rabbit hearts. Four groups of hearts were compared: control hearts from normal rabbits perfused with physiological buffer (5 mM glucose and 2 mM pyruvate added), hearts from alloxan-induced diabetic rabbits (same perfusion as control), hyperglycemic hearts from normal rabbits perfused with 22 mM glucose and 2 mM pyruvate, and hyperosmotic hearts from normal rabbits perfused with 5 mM glucose, 2 mM pyruvate, and 8.5 mM choline chloride. Hypoxia was produced by perfusion with a mixture of N2- and O2- saturated solutions. Endothelium-dependent and -independent dilators were also tested. Papaverine-induced coronary vasodilatation was unaltered, whereas that of serotonin and adenosine was significantly reduced in hyperglycemic and hyperosmotic hearts but not in diabetic hearts perfused with normoglycemic buffer. Hypoxia (PO2 from 515 +/- 86 to 131 +/- 24 mmHg; 1 mmHg = 133.3 Pa) caused a significant coronary vasodilatation in normal hearts (-66 +/- 3%). This vasodilatation was reduced slightly in diabetic (-45 +/- 7%, p < 0.05) and severely in hyperglycemic (-21 +/- 5%, p < 0.05) and hyperosmotic (-24 +/- 5%, p < 0.05) hearts. The adenosine-receptor antagonist 8-phenyltheophylline (10 microM) reduced hypoxia-induced vasodilatation in normal and diabetic hearts. However, inhibition of prostaglandin synthesis with diclofenac (1 microM), which reduces hypoxia-induced vasodilatation in normal hearts, had no effect in diabetic hearts. In conclusion, alloxan-induced type 1 diabetes mellitus in rabbits is accompanied by a reduced coronary vasodilator response to hypoxia. The contribution of adenosine in this response is unaffected. However, the abated contribution of cyclooxygenase products may account for the reduced vasodilatation during hypoxia in this particular model.  相似文献   
76.
Durban’s pursuit of economic development in the post-apartheid era   总被引:1,自引:1,他引:0  
The city in South Africa has “been forced to engage in serious soul-searching about their role in a new political order while facing up to complex and dynamic global economic forces” (Hall and Robbins, 2002, p. 43)  相似文献   
77.
Nanocrystalline MgA12O4 was synthesized by pyrolysis of the homogeneous spinel precursor, Mg(C4H5O2)2·(H2O):Al2(OH)3(C3H3O2)3·(H2O)2:NH4(C3H3O2)·(H2O). The spinel precursor gel is composed of a mixture of magnesium and aluminum acrylate salts dissolved in an ammonium acrylate gel. The reaction of acrylic acid with magnesium hydroxide in water produced magnesium methacrylate, and a similar reaction of basic aluminum acetate produced the aluminum salt of acrylic acid. The reaction of acrylic acid with ammonium hydroxide produced the ammonium acrylate gel. Ammonium acrylate gel was found to absorb many times its own weight of water. Although similar properties have been identified in PMMA and in the polymer of sodium acrylate, only the ammonium acrylate gel exists as an unpolymerized monomer. The spinel precursor gel is a pre-ceramic material that yields an amorphous oxide phase at 425°C that begins to crystallize to the MgAl2O4 spinel at 600°C and is fully crysta1line at 1030°C with a uniform particle size of 7-100 nm. The spinel precursor gel and the nanocrystalline MgA12O4 spinel were characterized by XRD and TEM.  相似文献   
78.
We have designed, implemented and assessed an EBMT system that can be dubbed the “purest ever built”: it strictly does not make any use of variables, templates or patterns, does not have any explicit transfer component, and does not require any preprocessing or training of the aligned examples. It uses only a specific operation, proportional analogy, that implicitly neutralizes divergences between languages and captures lexical and syntactic variations along the paradigmatic and syntagmatic axes without explicitly decomposing sentences into fragments. Exactly the same genuine implementation of such a core engine was evaluated on different tasks and language pairs. To begin with, we compared our system on two tasks of a previous MT evaluation campaign to rank it among other current state-of-the-art systems. Then, we illustrated the “universality” of our system by participating in a recent MT evaluation campaign, with exactly the same core engine, for a wide variety of language pairs. Finally, we studied the influence of extra data like dictionaries and paraphrases on the system performance.  相似文献   
79.
The interaction of small guest molecules with the molecular degrees of freedom of a glassy polymer matrix is investigated, i.e. (i) the dynamics of these guest molecules and (ii) their effect on the secondary ‘β’ and main ‘’ relaxations of the host polymeric matrix. The system considered here is the glassy poly(methyl metacrylate) modified by introduction and desorption of methanol. The dynamics of the system is observed by means of low-frequency mechanical and wide band dielectric spectroscopies. The presence of small molecules in the PMMA glassy matrix induces several effects, namely (i) a strong relaxation peak develops at low temperature (near 120 K at 1 Hz and called m in the following), (ii) the strength of the β relaxation is increased while the temperature of the maximum shifts towards the low temperatures, (iii) a sharp peak appears superimposed on the β peak, and finally (iv) the relaxation shifts towards the low temperatures. Dielectric and mechanical spectroscopies results are in agreement and make it possible to capture the dynamical behavior in a wide frequency range (eight decades). The experimental results are explained on the basis of physical concepts recently introduced in the physics of glassy matter: cooperativity and nanoheterogeneity. In particular, the low-temperature relaxation process m is attributed to cooperative motions in methanol clusters which form in the nanoheterogeneous polymeric matrix, in agreement with small angle X-rays scattering and low-frequency Raman scattering observations recently reported.  相似文献   
80.
The silt density index (SDI) and modified fouling index (MFI) characterisation methods are well known for the evaluation of membrane fouling potential of dispersed particulate matter (suspended solids, colloids) in a feed. The SDI and MFI methods, however, reduce the overall and very complex fouling phenomena into a one number value, on which the interpretation of the fouling potential of the feed is based. Considering such a one number characteristic, a significant amount of information from the fouling measurement (data) is lost. In this paper a concept is introduced in order to preserve such information and supplement the existing indexes. The proposed method measures, processes and presents data in a specific format. To illustrate the concept, some results are shown from measurements on three types of feed. Future systematic research will also include the measurement on some model feeds with, for example, well characterised dispersions for comparison purposes. However, based on the contents of this paper, a discussion on the method could be initiated.  相似文献   
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