Routine testing of producers' milk supplies for compositional quality using randomly selected samples

In a study over a number of months, involving over 500 milk producers in three locations, and representing bulk milk collection from cans as well as mobile and stationary refrigerated bulk milk tanks, the precision of various random sampling and testing frequencies in estimating the fat, protein and lactose content of milk was evaluated. In addition, the traditional procedure of estimating the composition of milk supplies from chemically preserved composites was compared to values obtained by analysis of fresh samples. While sampling and testing every milk collection gave the most precise estimate of milk composition for each producer, it was found that for producers using refrigerated bulk milk tanks with ex-farm collection, four random samples per month gave a precision of ±4% (or ±0.14% fat approx) for monthly fat content and ±l.2% (or ±0.04% fat approx) for annual fat content. Due to lower variability the precision for both protein and lactose estimation was much higher. The sample compositing procedure, while capable of a relatively high level of precision, did not always achieve this in practice and tended to underestimate the constituents in milk, especially protein and lactose.     

Inflorescence and bunch architecture development in Vitis vinifera L.

Inflorescence development from budburst to harvest was analysed in four cultivars of grapevine. Two cultivars with tight or compact bunches (Riesling, Chardonnay) and two with loose or open bunches (Exotic and Sultana) were selected to define differences in bunch development for future genetic analysis. A range of phenotypic characters for both inflorescence and shoot architecture were measured. Differences in the rate of rachis elongation rates were observed between tight and loose bunch cultivars commencing at the earliest stages of inflorescence development after budburst. At anthesis, five phenotypic characters showed significant differences between tight and loose cultivars: (1) total inflorescence length, (2) node number per inflorescence rachis, (3) combined length of two consecutive internodes of the rachis and (4) shoot node position at which the inflorescence was present and (5) mature tendril length. A quantitative estimate of bunch compactness was calculated at bunch maturity. Exotic and Sultana had significantly more open space than did compact bunch cultivars Riesling and Chardonnay. Comparison of flower number at anthesis and berry number at maturity indicated that the proportion of berries set was similar in all cultivars studied and, therefore, did not contribute to variability in bunch openness between cultivars. Internode length of the inflorescence rachis was the major trait responsible for inflorescence openness. Cellular studies using SEM, fluorescence microscopy and DNA content demonstrated that differences in rachis internode lengths were mostly associated with cell expansion.     

塔里木盆地东河塘组层序地层学研究

以塔里木盆地东河塘组为研究对象,通过大量野外剖面观测、钻井岩心观察,研究了东河塘组层序划分和 特征,共划分4个(SQ1、SQ2、SQ3、SQ4)3级层序,论述了不同层序在不同地区层序内体系域的构成特征;研究 了层序对比,得出各层序在不同地层分区发育程度不同。为了能更好地揭示东河塘组层序的发育、展布规律,分 别建立了东西和南北向的层序地层格架模型。     

ning reactions during storage of low-moisture Australian sultanas: Effects of vine nitrogen nutrition on subsequent arginine-mediated Maillard reactions during storage of dried fruit

Ten‐year old Vitis Vinifera L. cv. Sultana (Thompson Seedless) grape vines were transferred into large cement pots in low nitrate soil and supplemented with four levels of nitrogen application in the form of ammonium nitrate as follows: 0 g ( N₀ ), 8.5 g ( N₁ ), 17.0 g ( N₂ ) and 25.0 g ( N₃ ). Grapes were harvested from each nitrogen treatment, dipped and dried to low moisture (?11.4%) and subsequently stored for 10 months at 10^oC and at 30^oC in either the presence or absence of oxygen. The pre‐storage concentration of free arginine, free‐proline and total protein in the dried sultanas increased with soil nitrogen application. Skin‐polyphenoloxidase (PPO) activity was higher in sultanas with added soil nitrogen ( N₁, N₂, N₃ ), however pre‐storage differences in total phenolics, and the PPO substrate, trans‐caftaric acid, were not significantly different. After 10 months storage at 30^oC significant browning was observed in both the presence and absence of oxygen. Greater browning corresponded to higher soil‐nitrogen application rates. The concentration of skin trans‐caftaric acid did not decrease in N₀, N₁ or N₂ after 10 months at 30^oC, in either the presence or absence of oxygen, although some decreases were measured in the highest nitrogen sultanas ( N₃ ). While PPO oxidation of the phenolic substrate trans‐caftaric acid was not the primary route to browning, a number of Maillard reaction products (MRP) were present in both sultanas and arginine‐glucose model systems. Those products were separated via reverse phase HPLC and partially characterised by UV‐diode array spectroscopy. The lack of oxidation of trans‐caftaric acid observed in the nitrogen storage trial was confirmed in an accelerated browning experiment in low‐moisture sultanas, where despite browning at 50^oC after 12 days, no decreases in this primary substrate for PPO‐mediated oxidation were measured.     

基于改进蝠鲼优化算法的光伏组件参数辨识模型

为了解决当前光伏组件模型中存在的参数辨识精度低和稳定性差的问题,提出了一种基于折射学习机制的蝠鲼觅食优化算法的三二极管光伏组件参数辨识模型(RLMRFO-TDM)。该模型将差分进化机制融入到MRFO算法的种群更新环节,提高了MRFO算法的局部探索能力,并加快了MRFO算法收敛速度;引入折射学习机制改善了MRFO算法的随机性,提高了种群在搜索区域中的离散性和MRFO算法的全局搜索能力。利用基准测试函数,验证了RLMRFO算法的有效性;采用STP6-120/36和STM6-40/36两种光伏组件的数据集对RLMRFO-TDM模型的参数辨识进行性能测试,与其他模型相比,RLMRFO-TDM模型的辨识精度、稳定性以及收敛速度表现最优。     

Effect of water hardness on cooking characteristics of cowpea (Vigna unguiculata L. Walp) seeds

Cowpeas were cooked in water made hard (or soft) by the separate addition of similar concentrations of certain salts (CaCl₂, MgCl₂, or NaHCO₃). The beans were also cooked in hard tap water and in double distilled water before and after soaking in water. Hard water caused a significant decrease in softness, led to reduced water absorption, and also decreased solids loss in the cooked product, but it increased the cooking time and discolouration of the beans. Hard water also gave rise to a significant ( P <0.05) increase in mineral content, but it had less effect on the proximate composition of the cooked products.     

Browning reactions during storage of low-moisture Australian sultanas: Evidence for arginine-mediated Maillard reactions

Browning during storage of low‐moisture dried Vitis Vinifera L. cv. Sultana (Thompson Seedless) grapes was examined in a multifactorial treatment and storage trial. Grapevines were subjected to two different levels of sun exposure, harvested fruit was dipped and subjected to different drying treatments to obtain a range of initial moisture contents (a_w= 0.419–0.558). The storage effects of temperature (10^oC and 30^oC), and the presence of oxygen on colour change (CIE L*a*b* tristimulus values, hue‐angle (h_ab*)) and chroma (C_ab*) over a fourteen‐month period were observed. The most significant changes in colour were measured for samples stored at 30^oC, both aerobically and anaerobically, although the largest changes occurred in the presence of oxygen. Initial a_w had a strong effect on colour changes; higher a_w non‐sunfinished samples underwent more significant browning compared to lower a_w sunfinished controls regardless of their oxygen status. Changes in the concentration of the free‐arginine and free‐proline, the most abundant free amino acids in sultanas, were monitored throughout the storage period. Free arginine decreased significantly at 30^oC in both the absence and presence of oxygen, whereas free proline increased (at both 10^oC and 30^oC), implying that free proline did not play a role in browning reactions at those temperatures. In addition to the decreases in free arginine, the concentration of 5‐hydroxymethyl furfural (5‐HMF), a marker of Maillard browning reactions, increased significantly in samples stored at 30^oC. Significant differences in the concentrations of 5‐HMF under the two oxygen conditions indicated sultana Maillard reactions, and possibly other non‐enzymatic browning processes, were oxygen sensitive.     

NON-INTRUSIVE PARTICLE TRACKING SYSTEM FOR PARTICULATE FLOWS AND VIBRATED GRANULAR BEDS

ABSTRACT

A unique, non-intrusive particle tracking system based on the principle of magnetic induction coupling is presented. In this system, small transmitters are mounted inside the particle being tracked, and a set of receiving antennae surrounding the experimental apparatus. Based on the measured signals for induced voltages in the antennae, the three-dimensional trajectory of the particle is resolved by solving the inverse problem. The experimental system development, including hardware and data acquisition aspects, is also described. The system was tested through test experiments which include a real time trajectory. The results indicate that a system with three mutually orthogonal transmitters provides accurate results. This system is ideally suited for experimental investigation of segregation in vibrated beds. Results for such study of real trajectories of a single sphere rising in a mass of other spheres in a vibrated bed are also shown to demonstrate phenomena such as period doubling and bifurcation.     

Muscle Fiber–Connective Tissue Junctions in the Fish Blue Grenadier (Macruronus novaezelandiae). A Scanning Electron Microscope Study

The junctions between the muscle fibers and the connective tissue of blue grenadier (Macruronus novaezelandiae Hector) were studied using scanning electron microscopy. In fish before, during, and just after rigor mortis, the muscle fibers are attached to the myocommatal connective tissue sheets by fine collagenous fibrils. After chilled storage these fibrils deteriorate and the muscle fibers gradually detach from the myocommata. It appears that the fibrils are destroyed by endogenous collagenases and/or other proteinases.