Media and methods for isolation of aeromonads from fecal specimens. A multilaboratory study

An international multilaboratory study was conducted to establish the optimal combination of culture media, incubation time and temperature for recovery of aeromonads from stools using blood ampicillin (10 mg/l) agar (BAA), starch ampicillin (10 mg/l) agar (SAA), and cefsulodin irgasan novobiocin agar (CIN) with alkaline peptone water (APW) for enrichment. Optimal recovery of aeromonads (167/186) occurred using BAA (37 degrees C; 24 h) and CIN (25 degrees C; 48 h) with APW (25 degrees C; 24 h) subcultured to BAA (37 degrees C; 24 h) and CIN (25 degrees C; 48 h).     

A Bayesian reconstruction of the methodology of scientific research programmes

The paper is concerned with explaining some of the principal theoretical developments in elementary particle physics and discussing the associated methodological problems both in respect of heuristics and appraisal. Particular reference is made to relativistic quantum field theory, renormalization, Feynman diagram techniques, the analytic S-matrix and the Chew — Frautschi bootstrap.     

ISAF重构算法密度函数快速计算模型

球坐标系下的ISAF算法是一种新的20面体分子三维重构方法,该方法精度优于传统柱坐标系下的Fourier-Beseel算法,但其执行速度远低于Fourier-Bessel算法,严重制约了ISAF算法的实际应用.分析发现,在ISAF算法中密度函数计算是影响重构速度的主要瓶颈之一.针对上述问题,文中提出一种密度函数快速计算模型,该模型包括三个组成部分:球坐标系网格点密度函数快速计算方法、"球坐标系—直角坐标系"网格点密度函数转换方法、基于两阶段映射法的快速对称映射方法.该模型可以将密度函数计算阶段的时间复杂度由O[(LM)8]降低到O[(LM)7].采用Psv-F病毒数据进行实验,结果表明,在保证精度的前提下,该模型可以将密度函数的计算速度提高2个数量级,将三维重构整体速度提高30倍左右,并且随着数据规模的增大、重构精度的提高,该模型带来的加速比将进一步增大.     

Velocity sedimentation of tumor cells: A comparison of methods

Summary Tumor cells isolated from a murine fibrosarcoma were grown in primary culture for two days and then separated on a basis of size by velocity sedimentation. Centrifugal elutriation and STAPUT methods were compared for their ability to isolate biophysically unique tumor subpopulations. The isolated cell fractions were assayed for cell number, incorporation of triatiated thymidine and Coulter volume. Both methods were comparable with regard to ability to separate tumor cells on a basis of size. Elutriation had the advantage of speed but required sophisticated equipment. The STAPUT method was less expensive but required somewhat longer times for separation.Supported in part by NIH-NCI grants No. CA-06294 and CA-18628.     

A comparison of adaptive structural forecasting methods for electricity sales

This paper presents the results of a study to determine whether new forecasting technologies might be of use to electric utilities for sales forecasting up to 3 years into the future. The methods considered included ordinary least squares on dynamic structural models, autocorrelated error models, adaptive variance and adaptive parameter models. Overall, the more adaptive models performed best, but most of the methods proved vastly superior to simple least squares models which do not take dynamics into account.     

图像视频信号的压缩采样与稀疏重建

要视觉传感器通常不知道它们“看到”的现象之下的物理过程,以远远超出图像视频信号有效维度的Shannon／Nyquist采样率获取图像视频数据,从而导致了对图像视频信号的存储、传输等数字处理的巨大压力．压缩感知（compressivesensing,CS）理论表明：在某个线性变换域下稀疏的信号,可以利用少量的观测数据精确地重建,或在噪声情况下鲁棒地重建．压缩感知是实现图像视频信号有效维度采样的理论基础,为图像视频信号的采样、处理和识别等领域带来了前所未有的突破．本文对图像视频信号领域压缩感知面临的基本问题：压缩采样、稀疏重建模型及其优化求解算法的研究进展进行了综述．在采样方面,分析了图像视频信号随机观测矩阵和有结构观测矩阵的性能;在稀疏重建模型方面,从图像视频信号的稀疏先验性出发、介绍了分析型的重建模型和合成型重建模型的构建方法;在优化求解方面,针对重建模型,介绍了约束优化问题和无约束优化问题两类求解算法．以此为基础,分析了在图像视频领域压缩感知的理论与应用的进一步发展所面临的问题和挑战,展望了未来的发展方向．     

A comparison of methods for the inactivation of third component of guinea-pig complement

Riassunto Sono stati esaminati comparativamente tre reagenti per la titolazione di C₃, rispettivamente allestiti con siero di cavia inattivato con zymosan, formalina e «Liquoid». Le differenze esistenti tra essi sono state analizzate e discusse in base alle attuali conoscenze sulla natura del terzo componente complementare.

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Supported in part by Contract DA-49-007-MD-696 with the Office of the Surgeon General, Department of the Army.     

A comparison of methods for the extraction of amino acids from fungal mycelium

Résumé En comparant plusieurs techniques pour extraire l'amino-acide libre de la mycose fongique on a observé de grandes différences entre elles. L'eau bouillante et la méthyléthylcétone HCl se sont montrés les solvents les plus efficaces et donnant chromatogrammes les plus clairs.     

Epistemic divergence and the publicity of scientific methods

Epistemic divergence occurs when different investigators give different answers to the same question using evidence-collecting methods that are not public. Without following the principle that scientific methods must be public, scientific communities risk epistemic divergence. I explicate the notion of public method and argue that, to avoid the risk of epistemic divergence, scientific communities should (and do) apply only methods that are public.     

Serial reconstruction with the electron microscope of carotid body tissue. The type I cell nerve supply

Zusammenfassung Rekonstruktionen aus elektronenmikroskopischen Serienschnitten ergeben, dass einige Zellen von Typ I im Glomus caroticum durch eine effecrente Nervenfaser zu einem Komplex zusammengefasst werden. Underschiede in den Synapsen an der Oberfläche der Typ I-Zellen wurden nicht gefunden.     

Radicals and types: A critical comparison of the methodologies of Popper and Lakatos and their use in the reconstruction of some 19th century chemistry

Research programmes associated with two nineteenth-century chemical theories, Radical Theory and the Theory of Types are discussed. The purpose is to examine in a very general way how well the methodologies of Popper and Lakatos can account for the development of these programmes. The chemical discussion is prefaced by a critical comparison of certain aspects of the two above-mentioned philosophies.     

A Comparison of Box—Jenkins and objective methods for determining the order of a non-seasonal ARMA Model

This paper evaluates different procedures for selecting the order of a non-seasonal ARMA model. Specifically, it compares the forecasting accuracy of models developed by the personalized Box-Jenkins (BJ) methodology with models chosen by numerous automatic procedures. The study uses real series modelled by experts (textbook authors) in the BJ approach. Our results show that many objective selection criteria provide structures equal or superior to the time-consuming BJ method. For the sets of data used in this study, we also examine the influence of parsimony in time-series forecasting. Defining what models are too large or too small is sensitive to the forecast horizon. Automatic techniques that select the best models for forecasting are similar in size to BJ models although they often disagree on model order.     

Serodiagnosis of viral hepatitis A: rise in antibody titre and evaluation of three methods for detecting early and late antibodies

A serological investigation was made on patients with viral hepatitis A and individuals with a past history of this disease. Titration of antibody in sequential samples was found to be of no help in diagnosis. Separation of early (IgM) from late (IgG) antibodies by protein A or by 2-mercaptoethanol did not prove to be convenient for the serodiagnosis. A chromatographic separation of late and early antibody was found to be satisfactory, and equivalent to a radioimmunoassay for IgM-antibodies.     

Alternative methods of animal sacrifice: the effect on intestinal function in vitro.

The total fluid uptake of everted sacs of rat jejunum was compared in animals killed by stunning and decapitation, or anaesthetised with ether. Fluid transport was significantly higher in the tissue prepared from stunned and decapitated animals. It is suggested that etherization may have adverse effects on the physiological viability of subsequently isolated tissues.     

Isolation of human epidermal stem cells by adherence and the reconstruction of skin equivalents

The isolation of human epidermal stem cells is critical for their clinical applications. In the present study, we isolated three populations of epidermal keratinocytes according to their ability to adhere to collagen type IV: i.e., rapidly adhering (RA), slowly adhering (SA), and non-adhering (NA) cells. The aim of this study was to characterize RA cells and to investigate the possibility of using these cells for epidermis reconstruction. To identify RA cells, flow cytometric analysis was performed using anti-₆ integrin and anti-CD71 antibodies. RA cells express high levels of ₆ integrin and low levels of CD71, which are considered as markers of an epidermal stem cell nature. Furthermore, electron microscopy showed that RA cells are small and have a high nuclear to cytoplasmic ratio, whereas SA and NA cells have well-developed cellular organelles and abundant tonofilaments. Western blot analysis showed that RA cells are slow cycling and express p63, a putative epidermal stem cell marker, whereas SA and NA cells express c-Myc, which is known to regulate stem cell fate. To compare epidermal regenerative abilities, skin equivalents (SEs) were made using RA, SA, and NA cells. The epidermis constructed from RA cells was well formed compared to those formed from SA or NA cells. In addition, only SEs with RA cells expressed ₆ integrin and ₁ integrin at the basal layer. These results indicate that RA cells represent epidermal stem cells and are predominately comprised of stem cells. Therefore, the isolation of RA cells using a simple technique offers a potential route to their clinical application, because they are easily isolated and provide a high yield of epidermal stem cells.Received 2 July 2004; received after revision 20 August 2004; accepted 10 September 2004     

Storage of streptomyces in soft agar and by other methods

Zusammenfassung Luftmycel-Sporen werden mit Hilfe von Triton X-100 als Netzmittel suspendiert und die filtrierte, homogene, sehr dichte Suspension mit einer Agarlösung vermischt (Endkonzentration 1.25 Agar/l). Diese Sporenkonserve in Weichagar wird bei 5°C aufbewahrt und kann über Monate und sogar einige Jahre als Impfmaterial dienen. Es wird über Erfahrungen mit anderen Konservierungsmethoden für Streptomyceten berichten.