Computers,management and organization: Reflections on a pilot study

Results are presented of a pilot study dealing with the interaction between computers, management, and organization structures: a study carried out to explore the computerization phenomenon in a small sample of manufacturing firms. A short survey of the literature introduces the perspectives and objectives of the field study. Two main research outcomes are presented. Firstly, a theoretical scheme of analysis, based on the control system of administrative processes, is considered as a means of evaluating computer impact on the organization. Secondly, a set of specific hypotheses is introduced in order to analyse the empirical data.The following interactions between computers and organizational structures have been examined (while considering the firm as an open socio-technical system): technology and environment, organizational structure, automatized applications, and the computerization process.     

Turbo soft combining hybrid ARQ techniques: Theory and application to 3G wireless networks

This paper deals with the application of Hybrid Automatic Repeat reQuest (h-arq) techniques to allow reliable data communications in wireless 3G networks. Basically, retransmission of coded data is endowed with soft combining schemes applied, respectively, to packet replicas, or to decoding algorithm outputs. In particular, the proposed coding scheme takes advantage of error correction capabilities of the turbo codes, while the combining algorithm follows the diversity approach. The performance of the proposedh-arq schemes has been derived by means of a suitable analytical approach and numerical simulations in the case of a typical umts environment. The results highlight the good behavior of the proposed scheme in term of error rate, throughput, packet delivery delay and power reduction.     

Central and peripheral influences on retention of postural asymmetry in rats.

Four studies with 94 Long-Evans rats examined potential neural processes involved in retention of a peripherally induced postural asymmetry. In Exp I, dorsal and ventral spinal root section following varying intervals of stimulation successfully abolished peripherally induced hindlimb asymmetry. Exp II revealed that 50 min of ventral root stimulation, in the absence of central connection, was not effective in producing asymmetry persistence. Exp III attempted to more closely delineate the time parameters involved in peripherally induced asymmetry retention. Asymmetry was found to consistently outlast a spinal transection if 40 min of stimulation was given. In Exp IV, possible modulatory higher brain center influences on the retention processes were demonstrated. Asymmetry persistence was consistently observed in Ss that received 10, 20, 30, 40, or 50 min of hindlimb stimulation if 50 min were allowed to elapse between the onset of stimulation and spinal section. Results (1) suggest an active involvement of spinal reflex centers in the fixation process, (2) indicate that the manner in which reflex activity is altered is not crucial as long as underlying time parameters are adhered to, and (3) demonstrate that higher center influences can modulate retention of a postural asymmetry in a complex manner. (14 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

PdAg/alumina membranes prepared by high power impulse magnetron sputtering for hydrogen separation

The development of hydrogen purification membranes that meet market demands such as high purity, dynamic hydrogen production even at small scale, and reduced costs is still an open question. With this view, the present study aims at developing, for the first time, a method based on high power impulse magnetron sputtering for the deposition of Pd77Ag23 (wt%) films onto porous alumina substrates to achieve composite membranes with high hydrogen permeability and stability. This technique allows the deposition of films also on complex geometries and can be easily scaled up, thus making this technology a potential candidate for preparing high performing membranes. Membranes made by stable and porous alumina supports and metallic, dense and crystalline Pd₇₇Ag₂₃ layers, from 3.5 μm to 17 μm thick, have been prepared and tested. The membranes showed good hydrogen permeability values, showing flux values up to a maximum of 0.62 mol_H2 m^?2 s^?1 at 450 °C and ΔP of 300 kPa. The resistance to hydrogen embrittlement and the chemical inertness to syngas were also demonstrated.     

Deflections of Timoshenko beam with varying cross-section

Closed form solutions are presented for bending beams with linearly and (in the binomial form) parabolically varying depth and for bending beams with linearly varying width along the beam's length. The solutions are developed taking into account the shear deformation of the beam. The solutions are achieved, in an original way, by transforming the fourth-order differential equations with variable coefficients into fourth-order differential equations with constant coefficients. Though the solutions presented refer to three recurrent variations in the beam cross-section shape, the procedure outlined can be applied to beams with binomial variation (with any exponent) in the depth or width of the cross-section. Moreover, the solutions can be achieved for polynomial, exponential and sinusoidal load conditions. The solutions can be utilized to obtain the stiffness factors and the flexibility coefficients of beams in the analysis of frames. Closed form solutions for longitudinal displacements are also presented. The analytical solutions are applied to four recurrent beams commonly used in civil engineering practice and a comparison with a numerical procedure is made.     

New insights into the psychological dimension of wood–human interaction

The effect a wooden-built environment exerts on the physical and psychological well-being of people has mostly been investigated by evaluation, through a limited number of sensory modalities, of small size stimuli. In this research, two real-size wooden and plaster indoor settings were used to examine the influence of wood on people’s emotions and perceptions. Three questionnaires assessed participants’ multimodal sensory, affective, and cognitive responses to the settings (Semantic Differential questionnaire), their emotional state (Positive and Negative Affect Schedule), and their environmental behaviour and biophilia degree (Nature Relatedness Scale). The results revealed that wood induces more positive emotions than plaster, and that individual biophilia degree appears to influence the tactile, auditory, and olfactory evaluation of the settings. It furthermore indicates how wood used in real buildings positively influences human psychological well-being and highlights the importance of considering multiple sensory modalities when investigating wood–human interaction.     

Occurrence of biogenic amine-forming lactic acid bacteria in wine and cider

A collection of 810 lactic acid bacteria (LAB) strains isolated from wine and cider was screened for potential biogenic amine (BA) producers by combining molecular and phenotypic approaches. A newly developed multiplex PCR method allowed for the simultaneous detection of four genes involved in the production of histamine (histidine decarboxylase, hdc), tyramine (tyrosine decarboxylase, tyrdc) and putrescine (via either ornithine decarboxylase, odc, or agmatine deiminase, agdi) while TLC and HPLC analysis allowed for BA-production determination. One hundred and fifty-eight LAB strains were monitored by the molecular/phenotypic double approach and revealed a good correlation between genotypic and phenotypic data. Eighteen per cent of the tested strains were positive for at least one BA target gene with up to three detected simultaneously, in particular amongst Lactobacillus brevis and Lactobacillus hilgardii isolates for the tyrdc and agdi genes. The most frequent gene corresponded to the agdi gene detected in 112 strains (14% of all LAB strains) of 10 different LAB species. The tyrdc gene was detected in 67 strains represented by 7 different LAB species (8% overall), especially those isolated from wine. Lower levels of hdc⁺ (2% of strains) and especially odc⁺ (0.5% of strains) strains were observed. Interestingly, species that have never been described to carry BA-producing pathway genes were identified in this study. Furthermore, only one cadaverine-producer was detected and corresponded to Lactobacillus 30a, a collection strain not found in fermented beverages, although cadaverine is commonly detected in wines.     

Metabolic profile and biological activities of Lavandula pedunculata subsp. lusitanica (Chaytor) Franco: Studies on the essential oil and polar extracts

We investigated the metabolic profile and biological activities of the essential oil and polar extracts of Lavandula pedunculata subsp. lusitanica (Chaytor) Franco collected in south Portugal. Gas chromatography–mass spectrometry (GC–MS) analysis revealed that oxygen-containing monoterpenes was the principal group of compounds identified in the essential oil. Camphor (40.6%) and fenchone (38.0%) were found as the major constituents. High-performance liquid chromatography with diode array detection (HPLC–DAD) analysis allowed the identification of hydroxycinnamic acids (3-O-caffeoylquinic, 4-O-caffeoylquinic, 5-O-caffeoylquinic and rosmarinic acids) and flavones (luteolin and apigenin) in the polar extracts, with rosmarinic acid being the main compound in most of them. The bioactive compounds from L. pedunculata polar extracts were the most efficient free-radical scavengers, Fe²⁺ chelators and inhibitors of malondialdehyde production, while the essential oil was the most active against acetylcholinesterase. Our results reveal that the subspecies of L. pedunculata studied is a potential source of active metabolites with a positive effect on human health.     

Detection of frozen salt in pipes using gamma-ray spectrometry of potassium self-activity

Solar plants that use molten salts as heat transfer fluid need careful control to avoid the freezing of the salt in the pipes; if such a problem occurs, a diagnostic instrument to localize where is the frozen salt plug and to determine its length is useful. If the salt contains potassium (as is the case of the most common mixture used in solar plants, NaNO₃/KNO₃ 60/40% by weight), the gamma decay of the natural unstable isotope ⁴⁰K can be exploited to detect the frozen salt in a non-invasive way. Simulations and experimental results regarding the detectability of such plugs with different masses/lengths are presented.