Group Testing Algorithms: Bounds and Simulations

We consider the problem of nonadaptive noiseless group testing of N items of which K are defective. We describe four detection algorithms, the COMP algorithm of Chan et al., two new algorithms, DD and SCOMP, which require stronger evidence to declare an item defective, and an essentially optimal but computationally difficult algorithm called SSS. We consider an important class of designs for the group testing problem, namely those in which the test structure is given via a Bernoulli random process. In this class of Bernoulli designs, by considering the asymptotic rate of these algorithms, we show that DD outperforms COMP, that DD is essentially optimal in regimes where K ≥ √N, and that no algorithm can perform as well as the best nonrandom adaptive algorithms when K > N 0.35 . In simulations, we see that DD and SCOMP far outperform COMP, with SCOMP very close to the optimal SSS, especially in cases with larger K

Almost separable matrices

An m×n matrix A with column supports {Si} is k-separable if the disjunctions ⋃i∈KSi are all distinct over all sets K of cardinality k. While a simple counting bound shows that m>klog2n/k rows are required for a separable matrix to exist, in fact it is necessary for m to be about a factor of k more than this. In this paper, we consider a weaker definition of ‘almost k-separability’, which requires that the disjunctions are ‘mostly distinct’. We show using a random construction that these matrices exist with m=O(klogn) rows, which is optimal for k=O(n1−β) . Further, by calculating explicit constants, we show how almost separable matrices give new bounds on the rate of nonadaptive group testing

Interdisciplina: una oportunidad para entender los sistemas ambientales.

El presente trabajo tiene como objetivo hacer una breve discusión sobre el tema de la interdisciplinariedad. La información fueron obtenida durante el formación “Análisis de los Cambios En El uso y la Tierra de agua y la Seguridad en la Cuenca de alimentaria del Plata”, patrocinado por el Instituto de Capacitación del IAI en abril de 2011, en Asunción, Paraguay. En el programa se debatieron en el uso de conceptos de cambios de la tierra y, y los impulsores naturales humana de los cambios; la cobertura de la tierra, el de la cubierta (la geomorfología y el clima; perturbaciones inducidas y naturales por el hombre, la demanda de alimentos, fibra, y energía: expansión deforestación y de los ecosistemas agrícolas, la demanda de agua (riego, consumo). La interdisciplinariedad surge como una oportunidad de análisis, teniendo en cuenta la diversidad de temas a considerar en los estudios de los cambios en el uso de la tierra.bitstream/item/61880/1/Doc-136-Interdisciplina-Final.pd

Elementos conceptuales y metodológicos para la evaluación de impactos ambientales acumulativos (eiaac) en bosques subtropicales : el caso del este de salta, argentina

163-178Northern Argentina experienced an unprecedented deforestation rate of xerophitic forests as a consequence of agricultural expansion. In the Province of Salta, 26 percent of the forest were removed between 1977 and 2008. At the end of 2007, just before the No. 26331 Law of Native Forest Protection was voted by the Congress, the highest annual rate of deforestation was registered, reaching a value of 2.1 percent. Regarding this situation, indigenous people of Eastern Salta along with the "criollos" (local small ranchers) appealed to the National Supreme Court of Justice for legal protection. The Court requested the province to elaborate a Cumulative Environmental Effects Assessment (CEEA) regarding the process of logging and deforestation in four departments of Salta Province (San Martín, Rivadavia, Santa Victoria, and Orán). The aim of this work is to present a conceptual framework to conduct a CEEA in eastern Salta and to present the evidences and existing methodologies to characterize the impacts of deforestation. The conceptual framework suggested depends on the quantitative characterization of the changes in the provision level of key ecosystem services as a function of the stress and/or disturbance level (in this case deforestation). Based on the literature and our own data, the effects of deforestation on four key ecosystem services have been assessed: C dynamics, energy balance and greenhouse gases emissions, water dynamics and landscape structure. Deforestation produced emissions of 2000 t of CH 4, 200 t of N 2O, above 20 Gg of C/year, a 1.1 watt/m2 reduction in reflected radiation and 4400 TJ radiative energy emissions caused by deforestation fires, increases in the risk of soil salinization and landscape fragmentation. Considering these aspects of the structure and functioning of the ecosystems provides objective elements to evaluate management alternatives and to elaborate monitoring programmes. To consider such management and monitoring alternatives arises technical challenges but also institutional and political ones

Adherence issues related to sublingual immunotherapy as perceived by allergists

Objectives: Sublingual immunotherapy (SLIT) is a viable alternative to subcutaneous immunotherapy to treat allergic rhinitis and asthma, and is widely used in clinical practice in many European countries. The clinical efficacy of SLIT has been established in a number of clinical trials and meta-analyses. However, because SLIT is self-administered by patients without medical supervision, the degree of patient adherence with treatment is still a concern. The objective of this study was to evaluate the perception by allergists of issues related to SLIT adherence. Methods: We performed a questionnaire-based survey of 296 Italian allergists, based on the adherence issues known from previous studies. The perception of importance of each item was assessed by a VAS scale ranging from 0 to 10. Results: Patient perception of clinical efficacy was considered the most important factor (ranked 1 by 54% of allergists), followed by the possibility of reimbursement (ranked 1 by 34%), and by the absence of side effects (ranked 1 by 21%). Patient education, regular follow-up, and ease of use of SLIT were ranked first by less than 20% of allergists. Conclusion: These findings indicate that clinical efficacy, cost, and side effects are perceived as the major issues influencing patient adherence to SLIT, and that further improvement of adherence is likely to be achieved by improving the patient information provided by prescribers. © 2010 Scurati et al, publisher and licensee Dove Medical Press Ltd

Immunodetection of lymphocyte subpopulations involved in allograft rejection in a teleost, Dicentrarchus labrax (L.)

Monoclonal antibodies which recognize antigenic determinants expressed by T-cells and Ig-bearing cells, respectively, allowed lymphocyte subpopulations involved in allograft rejection of muscle transplants to be identified in the teleost fish Dicentrarchus labrax (L.). The monoclonal antibody DLT15 first allowed recognizing T-cells involved in an in vivo antigen- driven cellular response in teleosts. Immunohistochemical studies showed a high density of lymphocytes in allografts and provided evidence of predominance of T-cells. The heterogeneity of the cell populations recognized by the antibodies was evidenced by the different size, cytology, and staining patterns of T-cells and Ig-bearing cells

Apoptosis of thymocytes in developing sea bass Dicentrarchus labrax (L.).

This study showed occurrence of an apoptotic process throughout the thymic development of a teleost fish. The thymus of larvae and juveniles of Dicentrarchus labrax (L.) was processed for in situ end-labelling of fragmented DNA. Apoptotic cells were not found in the thymic anlage, and were first detected at day 35 post-hatching. Their number did not change significantly throughout early thymic development, while it increased at day 74 posthatching. Apoptotic thymocytes were more frequent in the cortex than in the medulla, and notably concentrated between the two regions. Apoptotic cells were less numerous in juvenile specimens, without changing the pattern of distribution. The apoptotic process has been confirmed by analysis for both high- and low-molecular weight DNA fragments and by cytomorphology

LA TECNICA NIRS NELLA VALUTAZIONE DI UOVA ED OVOPRODOTTI

The validity of l-lactic, succinic and d-3-hydroxybutyric acids as indicators of egg freshness and presence of incubator rejects were determined in 120 homogenized farm eggs using the Boehringer-Mannheim enzymic technique and subsequent NIR spectroscopy. Tests were carried out on fresh eggs and eggs held at 4 or 20\ub0C to simulate commercial conditions. The 3 acids proved highly suited as a measure of the eggs' freshness. l-lactic acid content increased considerably during storage, but did not exceed 500 mg/kg DM after 27 days at ambient temp., indicating that the Italian legal limit of 1000 mg/kg DM is set too high. Succinic and d-3-hydroxybutyric acid levels did not rise, but the former gave an indication of the hygienic quality of the eggs, and the latter revealed the presence of incubator egg rejects. NIR spectroscopy proved extremely valuable as a quality control technique, allowing accurate evaluation of the concn. of the 3 indicator acids, as well as providing a means of differentiating between different egg batches

In vivo allograft rejection in a bony fish Dicentrarchus labrax (L.): characterisation of effector lymphocytes.

Lymphoid cell subpopulations involved in allograft rejection in the teleost Dicentrarchus labrax were characterised at the ultrastructural level and quantified by using monoclonal antibodies against T- and B-lymphocytes. T-cells positive for T-cell receptor β-chain (TcRβ) were detected by reverse transcription/polymerase chain reaction (RT-PCR) and in situ hybridisation by using RNA probes for TcRβ. Flow cytometry detected a similar percentage of T- and B-lymphocytes (around 17%) in the leucocyte-enriched fraction from allografts. Two different types of T-lymphocytes (DLT15-immunoreactive) infiltrating the allografts were identified by cytomorphology: small cells with high nuclear/cytoplasmic ratio and cells with a higher cytoplasmic content. RT-PCR revealed a single band (513 bp) corresponding to the TcRβ. In situ hybridisation showed that TcRβ-positive cells in the grafted muscle fibres were less numerous compared with DLT15-positive cells, as evidenced in parallel sections, suggesting that cytotoxic cells might express different TcR phenotypes. DLIg3- immunoreactive Ig-producing lymphocytes had: 1) a high nuclear/cytoplasmic ratio or 2) a larger size similar to that of pre-plasma cells (plasma cells lacked any membrane labelling)