ESR Studies of Uncomplexed and Complexed HO2 Radical Formed in the Reaction of H2O2 with Ce4+, Fe2+ and Ti3+ Ions

Excess of H₂O₂ reacting in 0.5N HClO₄ with Ce⁴⁺, Ti³⁺ and Fe²⁺ yields the uncomplexed HO₂ radical. This radical gives a broad ESR signal with a line width of 27±1 gauss and a g-value of 2.0140±0.0015. The HO₂ radical forms a complex with excess of Ce³⁺ which gives an ESR spectrum with a linewidth of 1.3±0.1 gauss and a g-value of 2.0180±0.0005. The equilibrium between complexed [Ce³⁺‥HO₂] and uncomplexed HO₂ was studied. Two complexes are formed between HO₂ and [Ti⁴⁺…H₂O₂]. These complexes give two ESR signals with a linewidth of 0.7 ± 0.1 and 0.5± 0.1 gauss and g-value of 2.0140± ± 0.0005 and 2.0120± 0.0005 respectively.     

A hydrodynamic mechanism for attraction of undulatory microswimmers to surfaces (bordertaxis)

Although small nematodes significantly impact human and animal health, agriculture, and ecology, little is known about the role of hydrodynamics in their life cycles. Using the nematode Caenorhabditis elegans as a model undulatory microswimmer, we have observed that animals are attracted to and swim along surfaces. The attraction to surfaces does not require mechanosensory neuron function. In dilute swarms, swimmers aggregate near surfaces. Using resistive force-based theory, symmetry arguments, and direct hydrodynamic simulations, we demonstrate that forces resulting from the interaction between the swimmer-induced flow field and a nearby surface cause a short-range hydrodynamic torque that stirs the swimmers towards the surface. When combined with steric forces, this causes locomotion along the surface. This surface attraction may affect nematode mate and food finding behaviour and, in the case of parasitic nematodes, may facilitate host penetration. Surface attraction must be accounted for when studying animals'' responses to various stimuli, and suggests means of controlling undulatory microswimmers.     

Time required to determine performance variables and production efficiency of lactating dairy cows

Thirty-five lactating dairy cows throughout weeks of lactation (WOL) 16 to 30 were used to determine optimal time needed for reliable measurement of performance variables, and to classify the cows into high-, medium-, and low-efficiency groups. Individual performance variables [body weight (BW), dry matter intake (DMI), and milk production] were measured daily with a computerized monitoring system. Body condition was visually scored weekly and used to calculate retained or depleted body energy as a result of fat content change (RE_F). Milk composition was analyzed weekly. Body weight, DMI, and total recovered energy (RE), which represents energy in milk production plus RE_F, were summarized weekly. Efficiency was calculated as RE/DMI and as residual feed intake (RFI; i.e., the difference between actual and expected DMI), which was calculated from multiple linear regression of DMI dependence on BW^0.75 and RE. Unexpectedly, it was found that BW did not affect DMI and RE/DMI. Changes and relative changes in phenotypic coefficient of variation and correlations among data from shortened tests ranging from 1 wk (WOL 16) to a sequence of 15-wk tests were used to determine optimal test period durations for 5 traits: BW, DMI, RE, RE/DMI, and RFI. Traits were fitted into a mixed model with repeated measures. For each week, the traits were summarized as a sequence of cumulative data, starting from WOL 16 and cumulated over periods that increased in 1-wk steps up to WOL 16 to 29. Weekly cumulations were compared with those for entire test period (WOL 16 to 30). Consistency of each cow’s efficiency classification as high, medium, or low was tested by the total-agreement procedure; the kappa index P-value was used. Throughout WOL 16 to 30, the effects of increasing test period duration on between-animal coefficient of variation differed with respect to the various performance variables and RE/DMI: it tended to change with respect to BW, did not change with respect to DMI, and decreased with respect to RE and RE/DMI. In conclusion, compared with a 15-wk study, a 2-wk study can classify RFI and RE/DMI to 3 efficiency levels, with an individual correlation coefficient of 0.6. When the study was carried out over 3 wk or more, the lowest significant index of the classification was P < 0.004, the lowest individual correlation coefficient was 0.65, and its lowest significance was P < 0.01. The current study indicated that the insignificant effect of the BW of dairy lactating cows on their DMI should be validated in more studies.     

基于双 PSD 视觉的空间光点位置测量研究

目前基于光学测量法的空间目标位姿探测系统主要采用单目视觉和双目立体视觉两种，其中双目视觉得益于利用仿生学视差原理，通过光学三角测量法即可计算出目标的空间相对位置，从而得到广泛应用。此外，针对于传统CCD、CMOS视觉相机繁杂的图像处理过程，提出了将双目视觉原理与位置敏感探测器(PSD)结合应用于空间光点位置的探测方法，利用PSD探测响应速度快、分辨率高等特性，将图像处理转换为光电探测器的信号处理过程，并搭建了具体的合作光点的位置探测系统。实验结果表明，PSD视觉相X和Y方向坐标波动均在±130μm,且探测系统精准还原了空间光点在距离1 000 mm的160 mm×160 mm×200 mm立方体空间内的运动轨迹，其定位误差为4.35 mm,随深度每增加50 mm,误差增加约27%,系统的平均误差为7.30 mm,稳定性较好。     

锡渣的形成特点和减少措施

随着无铅钎料的广泛使用,波峰焊过程将产生更多的锡渣,造成生产成本增加。通过对其分布特点的研究,将锡炉熔融钎料表面氧化物分为A~E5个氧化物区,并分析了各区域氧化物的特点,列举了几种减少氧化渣的办法,分析了他们的实用性。     

Isogeometric analysis of shear bands

Numerical modeling of shear bands present several challenges, primarily due to strain softening, strong nonlinear multiphysics coupling, and steep solution gradients with fine solution features. In general it is not known a priori where a shear band will form or propagate, thus adaptive refinement is sometimes necessary to increase the resolution near the band. In this work we explore the use of isogeometric analysis for shear band problems by constructing and testing several combinations of NURBS elements for a mixed finite element shear band formulation. Owing to the higher order continuity of the NURBS basis, fine solution features such as shear bands can be resolved accurately and efficiently without adaptive refinement. The results are compared to a mixed element formulation with linear functions for displacement and temperature and Pian–Sumihara shape functions for stress. We find that an element based on high order NURBS functions for displacement, temperature and stress, combined with gauss point sampling of the plastic strain leads to attractive results in terms of rate of convergence, accuracy and cpu time. This element is implemented with a \(\overline{\hbox {B}}\) -bar strain projection method and is shown to be nearly locking free.     

Changing trends in three decades of psychotherapy research: The flight from theory into pragmatics.

Reviews 252 empirical studies of psychotherapy published in the Journal of Consulting and Clinical Psychology in the years 1967/1968, 1977/1978, and 1987/1988. Articles were rated on variables related to theoretical relevance, clinical validity, and methodology. It is shown that the main trend over this period of time has been a decline in theory-guided and a rise in pragmatic, clinically oriented research. Related changes in specific norms and practices in this area are illustrated. The disadvantages of a purely empirical approach to psychotherapy research are discussed, and recommendations are made in light of the distinction between the different aims of pragmatic and theoretical research. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The pluralist revolution: From the one true meaning to an infinity of constructed ones.

Argues that the truth of psychotherapy is not historical, disclosing a real fit between subjective recall and past events, but narrative (D. Spence, 1982). The story of clients' lives, which develops in therapy, is not the real history of the individual, but one possible narrative. Life narrative is inextricably linked to self-concept. Cure in psychoanalysis is not due to the uncovering of the past, but to the replacement of an inchoate life narrative by a congruent one, and the transformation of the meanings that previously blocked the person's ongoing story with new ones. Psychotherapeutic approaches provide metanarratives for the re-creation of life narratives that help therapists mend their clients' self-defeating narratives. Although a therapist's belief in his/her metanarrative is crucial, a pluralist position holds that no metanarrative is uniquely true. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Temporal segregation in coexisting Acomys species: the role of odour

To understand the mechanisms underlying displacement (the shift from nocturnal to diurnal activity), in one of the two coexisting spiny mice (genus Acomys), the effect of chemical cues released by A. cahirinus on the time of activity of A. russatus was tested Six golden spiny mice (A. russatus), which prior to the experiments were kept separate from common spiny mice (A. cahirinus), showed nocturnal activity. They were exposed to chemical cues from the urine and faeces of conspecific and heterospecific mice of the opposite sex. The onset of activity in these mice was recorded. While the urine and faeces of conspecific mice did not have a significant effect on the time of onset of activity, heterospecific urine and faeces did cause a significant (p < 0.001) time shift and, a day after they were introduced, activity started 6.8 +/- 1.9 h earlier. This shift also took place on the second day. The results of this study suggest that the mechanism for displacement of A. russatus from nocturnal activity is by chemical signals released by A. cahirinus. Therefore, it may be concluded that chemical cues maintain time separation between these two species.