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Background Osteoporotic vertebral fractures (VFs) often go unrecognised in both healthy individuals and in pathological conditions. Few data exist on VFs in patients hospitalised in Internal Medicine Units (IMUs), who often suffer from multiple concomitant chronic disorders. Aim of the study This multicentre cross-sectional study was aimed at assessing the prevalence of VFs in an unselected population of patients referring to IMUs. Correlations between VFs and the main coexisting diseases were also investigated. Methods Information on demographic, clinical and laboratory findings, and on the presence of known risk factors for osteoporosis was recorded. The Genant's semi-quantitative method was used to evaluate, in a central reading centre, the presence and severity of VFs in the thoracic and lumbar spine. Results A cohort of 995 patients was evaluated. At least one VF of any grade was found in 47.5% of patients, with similar prevalence between females (48.1%) and males (46.7%). Older age, chronic obstructive pulmonary disease, and previous diagnosis of osteoporosis showed a significant association with VFs in multivariable analysis. However, 79.7% of the VFs were observed in patients without previous diagnosis of osteoporosis. Moreover, a VF of grade 2 or greater was found in 20.8% of patients. Conclusions Fragility VFs is a very frequent finding in patients hospitalised in IMUs. Consequently, more attention should be devoted in this clinical setting to this comorbidity, which is known to be an additional factor for mortality and, when localised in the thoracic part of the spine, may negatively influence a concomitant respiratory insufficiency.

We demonstrate passive Q-switching (PQS) of the Tm-doped BaY2F8 (Tm:BYF) laser for the first time. The Tm:BYF laser is diode-pumped using an L-shaped hemispherical resonator. In the cw regime, the maximum output power with an 18% Tm-doped BYF crystal reached 1.12 W at ~1920 nm for an absorbed pump power of 3.06 W. In the PQS regime, maximum pulse energy (720 μJ) and peak power (17.1 kW) were obtained with an 8% Tm-doped BYF crystal and a Cr:ZnS saturable absorber with 92% low-signal transmission, again near 1920 nm, for a pulse width of ~40 ns and a repetition rate of 50 Hz.

Background Traditionally, pneumonia has been classified as either community- or hospital-acquired. Although only limited data are available, health care-associated pneumonia has been recently proposed as a new category of respiratory infection. "Health care-associated pneumonia" refers to pneumonia in patients who have recently been hospitalized, had hemodialysis, or received intravenous chemotherapy or reside in a nursing home or long-term care facility. Objective To ascertain the epidemiology and outcome of community-acquired, health care-associated, and hospital-acquired pneumonia in adults hospitalized in internal medicine wards. Design Multicenter, prospective observational study. Setting 55 hospitals in Italy comprising 1941 beds. Patients 362 patients hospitalized with pneumonia during two 1-week surveillance periods. Measurements Cases of radiologically and clinically assessed pneumonia were classified as community-acquired, health care-associated, or hospital-acquired and rates were compared. Results Of the 362 patients, 61.6% had community-acquired pneumonia, 24.9% had health care-associated pneumonia, and 13.5% had hospital-acquired pneumonia. Patients with health care-associated pneumonia had higher mean Sequential Organ Failure Assessment scores than did those with community-acquired pneumonia (3.0 vs. 2.0), were more frequently malnourished (11.1% vs. 4.5%, and had more frequent bilateral (34.4% vs. 19.7%) and multilobar (27.8% vs. 21.5%) involvement on a chest radiograph. Patients with health care-associated pneumonia also had higher fatality rates (17.8% [CI, 10.6% to 24.9%] vs. 6.7% [CI, 2.9% to 10.5%]) and longer mean hospital stay (18.7 days [CI, 15.9 to 21.5 days] vs. 14.7 days [CI, 13.4 to 15.9 days]). Logistic regression analysis revealed that depression of consciousness (odds ratio [OR], 3.2 [CI, 1.06 to 9.8]), leukopenia (OR, 6.2 [CI, 1.01 to 37.6]), and receipt of empirical antibiotic therapy not recommended by international guidelines (OR, 6.4 [CI, 2.3 to 17.6]) were independently associated with increased intrahospital mortality. Limitations The number of patients with health care-associated pneumonia was relatively small. Microbiological investigations were not always homogeneous. The study included only patients with pneumonia that required hospitalization; results may not apply to patients treated as outpatients. Conclusion Health care-associated pneumonia should be considered a distinct subset of pneumonia associated with more severe disease, longer hospital stay, and higher mortality rates. Physicians should differentiate between patients with health care-associated pneumonia and those with community-acquired pneumonia and provide more appropriate initial antibiotic therapy.

Scholars studying the origins and evolution of language are also interested in the general issue of the evolution of cognition. Language is not an isolated capability of the individual, but has intrinsic relationships with many other behavioral, cognitive, and social abilities. By understanding the mechanisms underlying the evolution of linguistic abilities, it is possible to understand the evolution of cognitive abilities. Cognitivism, one of the current approaches in psychology and cognitive science, proposes that symbol systems capture mental phenomena, and attributes cognitive validity to them. Therefore, in the same way that language is considered the prototype of cognitive abilities, a symbol system has become the prototype for studying language and cognitive systems. Symbol systems are advantageous as they are easily studied through computer simulation (a computer program is a symbol system itself), and this is why language is often studied using computational models.

Recent views of categorization suggest that categories are action-based rather than arbitrary symbols. Three connectionist simulations explore the hierarchical organization of categories in the framework of an action-based theory of categorization. In the simulations an organism with a visual system and a two-segment arm has to reach different points in space depending on the object seen and on context. The context indicates whether to put the object in a superordinate or in a basic category. The results show that: (a) superordinate categories are easier to learn than basic ones; (b) the more similar the actions to perform with basic and superordinate categories, the easier to learn the task; (c) violation of category boundaries leads to less good performance.

In two Artificial Life simulations we evolved artificial organisms possessing a visual and a motor system, and whose nervous system was simulated with a neural network. Each organism could see four objects, either upright or reversed, with a left or a right handle. In Task 1 they learned to reach the object handle independently of the handle‟s position. I, in Task 2 they learned to reach one of two buttons located below the handle either to decide either where the handle was (Simulation 1) or whether the object was upright or reversed (Simulation 2). Task 1 simulated real life experience, Task 2 replicated either a classic spatial compatibility task (Simulation 1) or an experiment by Tucker & Ellis (1998) (Simulation 2). In both simulations learning occurred earlier in the Compatible condition, when the button to reach and the handle were on the same side, than in the Incompatible condition.

We present a model based on genetic algorithm and neural networks. The neural networks develop on the basis of an inherited genotype but they show phenotypic plasticity, i.e. they develop in ways that are adapted to the specific environment The genotype-to-phenotype mapping is not abstractly conceived as taking place in a single instant but is a temporal process that takes a substantial portion of an individual's lifetime to complete and is sensitive to the particular environment in which the individual happens to develop. Furthermore, the respective roles of the genotype and of the environment are not decided a priori but are part of what evolves. We show how such a model is able to evolve control systems for autonomous robots that can adapt to different types of environments.

Internal representations of the environment are often invoked to explain performance in tasks in which an organism must make a detour around an obstacle to reach a target and the organism can lose sight of the target along the path to the target. By simulating a detour task in evolving populations of robots (Khepera) we show that neural networks with memory units perform better than networks without memory units in this task. However, the content of the memory units need not be interpreted as an internal representation of the position of target. The memory units send a time-varying internally generated input to the network's hidden units that allows the network to generate the appropriate behavior even when there is no external input. Networks without memory units do not have this internal input and this explains their inferior performance.

Neural networks simulate simple organisms that evolve in a two-dimensional environment (with selective reproduction and mutation) on the basis of a fitness criterion which rewards residing in favorable environmental zones and obtaining food. The evolution of two different populations of organisms is studied: organisms that are informed of the environmental zone they are in at any particular time and organisms that are not so informed. The results show that the behavioral strategies that evolve in the two populations closely reflect the differences between the two types of organisms. Furthermore, the course of evolution can be divided into different successive phases which are characterized by different behavioral strategies. The initial strategies are evolutionarily unstable because they tend to be replaced by new more effective strategies introduced by mutants, until final stable strategies emerge which differ in the two populations because of their different evolutionary history. >