The nutritional status of fishing and non-fishing communities of Lake Victoria basin

We examined socio-economic variables that contribute to malnutrition in selected communities in the Lake Victoria basin during 2001. The study was carried out in nine districts and hinterland communities up to 25 km awayfrom the beach were used as the reference population. The main variables examined were: feeding habits, income and intra-household food distribution and living standards. Others included disease and health, sanitation and hygiene, childcare and mothers' age and workload, weaning practices, agricultural production and food availability, care during pregnancy and food taboos.

Wetlands and riparian zones as buffers and critical habitats for biotic communities in Lake Victoria

Despite their ecological and socio-economic importance, Lake Victoria's adjoining "swamps" and lake interface are among the least investigated parts of the lake. The "swamps" a term commonly equated to "wastelands" and the difficult working environment they present in comparison to open water, are major factors for the low level of attention accorded to shoreline wetlands. Moreover, definitions of wetlands highlighted for example in the Ramsar Convention as "areas of marsh, fern, peatland or water, whether natural or artificial, permanent or temporary, with water that is static or flowing, fresh or brackish, or salt, including areas of marine water, the depth of which does not exceed six metres" (Ramsar, 1971) were designed to protect birds (water fowl) of international importance. The Ramsar definition, which also includes oceans, has till recently been of limited use for Lake Victoria, because itdoes not fully recognise wetlands in relation to other public concerns such as water quality, biodiversity and the tisheries that are of higher socioeconomic priority than waterfowl. Prior to 1992, fishery research on Lake Victoria included studies of inshore shallow habitats of the lake without specific reference to distance or the type of vegetation at the shore. Results of these studies also conveniently relied heavily on trawl and gill net data from the 5-10 m depth zones as the defining boundary of shallow inshore habitats. In Lake Victoria, such a depth range can be at least one kilometre from the lake interface and by the 10m depth contour, habitats are in the sub-littoral range. Findings from these studies could thus not be used to make direct inferences on the then assumed importance of Lake Victoria wetlands in general.

La reproducción de la merluza en el Mar Argentino (Merlucciidae, Meluccius merluccius hubbsi) : 1. Descripción histológica del ciclo del ovario de merluza

The present paper deals on the histological description of the hake ovary made on the basis of gonad observations of 394 females during the period April 1966 March 1967. The material was obtained from weekly sampling of commercial catches carried out at the Institute of Marine Biology (Prov. Buenos Aires, Argentina). The anatomical and histological description of the standard ovary and the adopted terminology are given. The maturation process is divided into five periods, from ovocyte formation to yolked ovocyte formation, with its histological description. Ovary changes are analyzed on detail. The following conclusions were outlined: 1. Analysis demonstrated that although some specimens were totally spawned others, at the end of the spawning period, retaining a great number of ovocytes in different maturity stages. Therefore, postspawners have been classified as follows: Postspawned II : This stages is characterized by the empty ovarian structure, with ovocytes in stage II, which will remain in the resting phase untill next spawning season. Postspawned III and IV: Their main characteristics are: tissue destruction, bloody residuals and remaining ovocytes in stage III and IV, respectively. 2. Some transformations were found in ovaries of postspawned III and IV. They are classified as follows, according to its origin and structure: Developed from follicular cell membrane – a) Glandular formations, b) Epiteloid formations - Originated from remaining ovocytes, c) Ovocyte disintegration, d) Ovocyte with follicular cell infiltration. 3. All those structures derived from postpawners III and IV have a temporary character and will be reabsorbed. Their presence delay the recuperation of the organ and its reproductive functions. Consequently, the possibility of those structures acting as control mechanisms is suggested. 4. Transformations pointed out in paragraph Nº 2 prevent the possibility of consecutive spawning originated from the remaining ovocytes (II and IV). 5. No structures originated from postspawners III and IV were found during summer season. 6. Reproductive cycle of hake has been described monthly. It was observed that maturing ovaries predominate in summer (November-December).

Visuomotor feedback gains upregulate during the learning of novel dynamics.

At an early stage of learning novel dynamics, changes in muscle activity are mainly due to corrective feedback responses. These feedback contributions to the overall motor command are gradually reduced as feedforward control is learned. The temporary increased use of feedback could arise simply from the large errors in early learning with either unaltered gains or even slightly downregulated gains, or from an upregulation of the feedback gains when feedforward prediction is insufficient. We therefore investigated whether the sensorimotor control system alters feedback gains during adaptation to a novel force field generated by a robotic manipulandum. To probe the feedback gains throughout learning, we measured the magnitude of involuntary rapid visuomotor responses to rapid shifts in the visual location of the hand during reaching movements. We found large increases in the magnitude of the rapid visuomotor response whenever the dynamics changed: both when the force field was first presented, and when it was removed. We confirmed that these changes in feedback gain are not simply a byproduct of the change in background load, by demonstrating that this rapid visuomotor response is not load sensitive. Our results suggest that when the sensorimotor control system experiences errors, it increases the gain of the visuomotor feedback pathways to deal with the unexpected disturbances until the feedforward controller learns the appropriate dynamics. We suggest that these feedback gains are upregulated with increased uncertainty in the knowledge of the dynamics to counteract any errors or disturbances and ensure accurate and skillful movements.

Deep mixing for excavation support: Design issues

Deep mixing is effectively used in excavations both in conjunction with and in substitution of traditional techniques, where it results in more economical and convenient solutions for the stability of the system and the prevention of seepage. Deep mixed walls constructed as part of a soldier pile and tie-backs system act also as temporary support, prevent seepage like a sheet pile wall, but require a lower amount of steel. The deep mixed treatment can also contribute to the stability of the wall system against deep-seated failures. Although deep mixing is currently used for excavation control in numerous projects, no standard procedure has been developed and the different applications have not been evaluated. As this technique emerges as a more economical and effective alternative to traditional excavation shoring, there is a need for guidelines describing proven procedures for evaluation of design, analysis and construction. This paper presents comparisons in the design of excavation support using deep mixing and other traditional techniques. Issues important for design, analysis, and construction of deep mixed excavation walls are also discussed.

Thermodynamic formulation of flowing soft matter with transient forces

The Responsive Particle Dynamics model is a very efficient method to account for the transient forces present in complex fluids, such as solutions of entangled polymers. This coarse-grained model considers a solution of particles that are made of a core and a corona. The cores typically interact through conservative interactions, while the coronae transiently penetrate each other to form short-lived temporary interactions, typically of entropic origin. In this study, we reformulate the resulting rheological model within the general framework of nonequilibrium thermodynamics called General Equation for the Nonequilibrium Reversible-Irreversible Coupling. This allows us to determine the consistency of the model, from a mechanistic and thermodynamic point of view, and to isolate the reversible and irreversible contributions to the dynamics of the model system. © 2012 Springer-Verlag Berlin Heidelberg.

Nanotubes complexed with DNA and proteins for resistive-pulse sensing

We use a resistive-pulse technique to analyze molecular hybrids of single-wall carbon nanotubes (SWNTs) wrapped in either single-stranded DNA or protein. Electric fields confined in a glass capillary nanopore allow us to probe the physical size and surface properties of molecular hybrids at the single-molecule level. We find that the translocation duration of a macromolecular hybrid is determined by its hydrodynamic size and solution mobility. The event current reveals the effects of ion exclusion by the rod-shaped hybrids and possible effects due to temporary polarization of the SWNT core. Our results pave the way to direct sensing of small DNA or protein molecules in a large unmodified solid-state nanopore by using nanofilaments as carriers. © 2013 American Chemical Society.

Generating suspended cell monolayers for mechanobiological studies.

Cell monolayers line most of the surfaces and cavities in the human body. During development and normal physiology, monolayers sustain, detect and generate mechanical stresses, yet little is known about their mechanical properties. We describe a cell culture and mechanical testing protocol for generating freely suspended cell monolayers and examining their mechanical and biological response to uniaxial stretch. Cells are cultured on temporary collagen scaffolds polymerized between two parallel glass capillaries. Once cells form a monolayer covering the collagen and the capillaries, the scaffold is removed with collagenase, leaving the monolayer suspended between the test rods. The suspended monolayers are subjected to stretching by prying the capillaries apart with a micromanipulator. The applied force can be measured for the characterization of monolayer mechanics. Monolayers can be imaged with standard optical microscopy to examine changes in cell morphology and subcellular organization concomitant with stretch. The entire preparation and testing protocol requires 3-4 d.

EFFECTS OF IRON ON PHYSIOLOGICAL AND BIOCHEMICAL CHARACTERISTICS OF Microcystis wesenbergii (Kom.) Kom. (Cyanobacterium)

Iron is an essential trace element for biological requirements of phytoplankton. Effects of iron on physiological and biochemical characteristics of Microcystis wesenbergii were conducted in this study. Results showed that 0.01 mu M [Fe3+] seriously inhibited growth and chlorophyll synthesis of M. wesenbergii, and induced temporary increase of ATPase activities, however, NR. ACP and ALP activities were restrained by iron limitation. Interestingly, iron addition on day 8 resulted in the gradual restoration of structures and functions of above enzymes and resisted a variety of stresses from iron limitation. M. wesenbergii in 10 mu M [Fe3+] treatment group grew normally. enzymes maintained normal levels, and residual phosphate contents in cultures first sharply decreased, then smoothly as M. wesenbergii has a characteristic of luxury consumption of phosphorus. Above parameters in 100 mu M [Fe3+] treatment group were almost same with those in 10 mu M [Fe3+] treatment group except for NR, ACP and ALP activities. In 100 mu M [Fe3+] treatment group, activities of ACP and ALP had temporary increase because phosphate and ferric iron could form insoluble compound - ferric phosphate (Fe3PO4) through adsorption effect. resulting in lack of bioavailable phosphate in culture media. The experiment suggested that too low or too high iron can affect obviously physiological and biochemical characteristics of M. wesenbergii.

Increasing allowable deformation criteria through application of level II LTSM approach

In the central part of the Delft railway tunnel project, an underground railway station is being built at very close distance to the existing station building, which is still in operation. Although elaborate sensitivity analyses were made, some unforeseen deformations were encountered during the first phases of the execution process. Especially the installation of temporary sheet pile walls as well as the installation of a huge amount of grout anchor piles resulted in deformations exceeding the predicted final deformations as well as the boundary values defined by a level I limiting tensile strain method (LTSM) approach. In order to ensure the execution process, supplementary analyses were made to predict future deformations, and this for multiple cross sections. These deformations were implemented into a finite element model of the masonry of the building in order to define probable crack formation. This Level II LTSM approach made it possible to increase the initially foreseen deformation criteria and the continuation of the works. Design steps, design models and monitoring results will be explained within this paper.

影响杜泊羊胚胎移植妊娠率和新生个体生长发育的因素：受体和移植季节

胚胎移植具有加速家畜良种推广的潜力。胚胎移植能直接引入纯种动物，并且能避免直接进口动物时可能会带来一些较大传染病（例如口蹄疫）的风险，因此具有成本低、安全性高、直接引入良种的特点。但是胚胎移植的成功率可能会受到很多因素的影响。这些因素可归纳为三个方面：胚胎因素；胚胎和受体的相互作用；受体因素。另一方面，胚胎移植目的是为了获得优秀生产性能的良种个体，但是出生的后代的生长发育情况也会和很多因素有关，例如出生大小、当地气候条件、饲养条件和胚胎移植季节等。因此，研究影响胚胎移植妊娠率以及出生后代生长发育的因素对胚胎移植在生产中的应用有重要意义。杜泊羊作为一种肉用绵羊，品种优良，经济价值很高，被认为应予以积极推广。用胚胎工程对杜泊羊进行推广可能是一个较好的办法。绵羊胚胎工程近年来已经取得了较大进展，例如超数排卵、体外胚胎生产、胚胎冷冻和胚胎移植的研究都取得了一系列的成果。在影响绵羊胚胎移植效果的具体因素中，已有一些关于不同胚胎移植数目、胚龄、冻胚和鲜胚、胚胎移植方法等报道，但是受体品种对杜泊羊的胚胎移植的研究还未见报道，季节对杜泊羊胚胎移植的影响的研究结果也不一致。因此本实验应用质量稳定的胚胎，采用单胚移植，以移植的妊娠率为指标，研究了受体品种和季节因素对杜泊羊冷冻胚胎移植成功率影响，结果发现在三个不同品种的受体中，胚胎移植妊娠率无显著差异（P＞0．05）；但是季节对胚胎移植成功率有显著影响，秋季移植妊娠率（68.6％）显著高于春季（58.5％，P＜0.05）。在山羊等其他动物的研究中表明，受体情况不影响胚胎移植出生的后代的生长发育。本实验以羔羊的出生重、1个月体重和断乳时（2个月时）体重为指标，分析了受体体重和季节对胚胎移植出生杜泊羊羔羊的早期生长发育的影响，结果表明，不同体重的受体会影响羔羊的出生重（P＜0.05），即体重较大的受体出生的羔羊的体重也较大，但经过两个月的哺乳期生长后，羔羊的生长发育情况已无明显差异（P＞0.05）。有研究表明羔羊早期的生长发育情况和外界条件有关。不同季节进行胚胎移植，羔羊出生时间也不同。因此，实验研究了不同季节对胚胎移植出生羔羊早期生长发育的影响。结果发现，季节显著影响了羔羊的生长发育，春季和秋季移植出生的羔羊在出生重方面差异不显著（P＞0.05），但春季移植出生的羔羊的后来的生长情况要明显好于秋季（P＜0.05）。

液驱式间歇浸没培养系统的研制

本文以菩提树为培养对象，采用改进的液驱式间歇浸没培养技术进行组织培养实验。为了更准确，精密地控制培养条件我们研制了间歇浸没式植物培养箱；为了提高培养效率，降低成本，我们对现有培养系统和方法进行了改进。鉴于液驱式间歇浸没培养半开放等培养特点，容易造成雪崩式污染。通过调查污染来源，研究各种物理化学生物杀菌抑菌方法的特点，以及对各个培养环节的消毒能力，建立了一套适合菩提树间歇浸没无糖培养的污染控制操作规程，为进一步大规模的商业化生产打下坚实的基础。 研究结果表明， 1、利用液驱式间歇浸没系统装置(简写为TD-TIB)进行组织培养，效率更高，成本更低。 液驱式间歇浸没培养与RITA和TIB相比，简单易操作，能耗低，效率高，成本低。与间歇浸没式植物培养箱配合使用，能够精密控制环境培养参数，包括温湿度，二氧化碳氧气的全程自动化检测控制 ，能够实现远程实时控制。利用液驱式培养方法生根后的培养苗自养光合能力强，驯化时间短，成活率高，芽多，健壮。 2、操作规程能够控制半开放间歇浸没培养中的污染问题。 从对紫外，臭氧，酒精，抗生素，杀菌剂以及过滤等污染控制方法的研究我们得出，任何一种消毒杀菌方法都不能控制系统的污染，只有结合培养系统环节和消毒方法的特点，把各种方法有机组合起来才能控制半开放条件下的污染。预处理是整个控制过程的关键。按照该操作规程，在2min/2h的间歇频率下的无糖间歇培养中，30天内成功实现了菩提树的生根驯化实验，培养液无污染。 间歇浸没培养技术与污染控制技术相结合实现了小范围的规模化培养，为大规模自动化组织培养技术奠定了坚实的基础。

燕儿沟流域泥沙监测初报

对燕儿沟综合治理试验示范区水文泥沙监测资料作一通报 ,并以获得的泥沙资料为基础 ,对燕儿沟流域的治理减沙及泥沙来源情况作了初步分析 ,结果表明 :燕儿沟流域年输沙量有明显的递减趋势 ,并提出了目前监测工作存在的一些问题 ,以便为专题组工作顺利进行提供科学依据

Shape memory effect of poly(L-lactide)-based polyurethanes with different hard segments

A series of biodegradable polylactide-based polyurethanes (PLAUs) were synthesized using PLA diol (M-n = 3200) as soft segment, 4,4 '-diphenylmethane diisocyanate (MDI), 2,4-toluene diisocyanate (TDI), and isophorone diisocyanate (IPDI) as hard segment, and 1,4-butanediol as chain extender. The structures and properties of these PLAUs were studied using infrared spectroscopy, differential scanning calorimetry, tensile testing, and thermomechanical analysis. Among them, the MDI-based PLAU has the highest T-g, maximum tensile strength, and restoration force, the TDI-based PLAU has the lowest T-g, and the IPDI-based PLAU has the highest tensile modulus and elongation at break. They are all amorphous. The shape recovery of the three PLAUs is almost complete in a tensile elongation of 150% or a twofold compression. They can keep their temporary shape easily at room temperature (20 degrees C). More importantly, they can deform and recover at a temperature below their T-g values. Therefore, by selecting the appropriate hard segment and adjusting the ratio of hard to soft segments, they can meet different practical demands for shape memory medical devices.

Effect of annealing on the viscoelastic and viscoplastic responses of low-density polyethylene

Two series of tensile tests with constant crosshead speeds (ranging from 5 to 200 mm/min) and tensile relaxation tests (at strains from 0.03 to 0.09) were performed on low-density polyethylene in the subyield region of deformations at room temperature. Mechanical tests were carried out on nonannealed specimens and on samples annealed for 24 h at the temperatures T = 50, 60, 70, 80, and 100 degreesC. Constitutive equations were derived for the time-dependent response of semicrystalline polymers at isothermal deformations with small strains. A polymer is treated as an equivalent heterogeneous network of chains bridged by temporary junctions (entanglements, physical crosslinks, and lamellar blocks). The network is thought of as an ensemble of mesoregions linked with each other. The viscoelastic behavior of a polymer is modeled as a thermally induced rearrangement of strands (separation of active strands from temporary junctions and merging of dangling strands with the network). The viscoplastic response reflects sliding of junctions in the network with respect to their reference positions driven by macrostrains. Stress-strain relations involve five material constants that were found by fitting the observations.