Atomistic Simulations of Nanotube Fracture

The fracture of carbon nanotubes is studied by atomistic simulations. The fracture behavior is found to be almost independent of the separation energy and to depend primarily on the inflection point in the interatomic potential. The rangle of fracture strians compares well with experimental results, but predicted range of fracture stresses is marketly higher than observed. Various plausible small-scale defects do not suffice to bring the failure stresses into agreement with available experimental results. As in the experiments, the fracture of carbon nanotubes is predicted to be brittle. The results show moderate dependence of fracture strength on chirality.Comment: 12 pages, PDF, submitted to Phy. Rev.

A mesoscopic ring as a XNOR gate: An exact result

We describe XNOR gate response in a mesoscopic ring threaded by a magnetic flux $\phi$. The ring is attached symmetrically to two semi-infinite one-dimensional metallic electrodes and two gate voltages, viz, $V_a$ and $V_b$, are applied in one arm of the ring which are treated as the inputs of the XNOR gate. The calculations are based on the tight-binding model and the Green's function method, which numerically compute the conductance-energy and current-voltage characteristics as functions of the ring-to-electrode coupling strength, magnetic flux and gate voltages. Our theoretical study shows that, for a particular value of $\phi$ ($=\phi_0/2$) ($\phi_0=ch/e$, the elementary flux-quantum), a high output current (1) (in the logical sense) appears if both the two inputs to the gate are the same, while if one but not both inputs are high (1), a low output current (0) results. It clearly exhibits the XNOR gate behavior and this aspect may be utilized in designing an electronic logic gate.Comment: 8 pages, 5 figure

Benthic foraminifera as tracers of brine production in the Storfjorden "sea ice factory"

The rapid response of benthic foraminifera to environmental factors (e.g. organic matter quality and quantity, salinity, pH) and their high fossilisation potential make them promising bio-indicators for the intensity and recurrence of brine formation in Arctic seas. Such an approach, however, requires a thorough knowledge of their modern ecology in such extreme settings. To this aim, seven stations along a north-south transect across the Storfjorden (Svalbard archipelago) have been sampled using an interface multicorer. This fjord is an area of intense sea ice formation characterised by the production of brine-enriched shelf waters (BSW) as a result of a recurrent latent-heat polynya. Living (rose bengal-stained) foraminiferal assemblages were analysed together with geochemical and sedimentological parameters in the top 5 cm of the sediment. Three major biozones were distinguished. (i) The inner fjord zone, dominated by typical glacier proximal calcareous species, which opportunistically respond to fresh organic matter inputs. (ii) The deep basins and sill zone, characterised by glacier distal agglutinated fauna; these are either dominant because of the mostly refractory nature of organic matter and/or the brine persistence that hampers the growth of calcareous species and/or causes their dissolution. (iii) The outer fjord zone, characterised by typical North Atlantic species due to the intrusion of the North Atlantic water in the Storfjordrenna. The stressful conditions present in the deep basins and sill (i.e. acidic waters and low food quality) result in a high agglutinated = calcareous ratio (A=C). This supports the potential use of the A=C ratio as a proxy for brine persistence and overflow in Storfjorden

Pituitary block with gonadotrophin-releasing hormone antagonist during intrauterine insemination cycles: a systematic review and meta-analysis of randomised controlled trials

BACKGROUND: Several randomised controlled trials (RCTs) have investigated the usefulness of pituitary block with gonadotrophin-releasing hormone (GnRH) antagonists during intrauterine insemination (IUI) cycles, with conflicting results. OBJECTIVE: The aim of the present systematic review and meta-analysis of RCTs was to evaluate the effectiveness of GnRH antagonist administration as an intervention to improve the success of IUI cycles. SEARCH STRATEGY: Electronic databases (MEDLINE, Scopus, EMBASE, Sciencedirect) and clinical registers were searched from their inception until October 2017. SELECTION CRITERIA: Randomised controlled trials of infertile women undergoing one or more IUI stimulated cycles with GnRH antagonists compared with a control group. DATA COLLECTION AND ANALYSIS: The primary outcomes were ongoing pregnancy/live birth rate (OPR/LBR) and clinical pregnancy rate (CPR). Pooled results were expressed as odds ratio (OR) or mean differences with 95% confidence interval (95% CI). Sources of heterogeneity were investigated through sensitivity and subgroups analysis. The body of evidence was rated using GRADE methodology. Publication bias was assessed with funnel plot, Begg's and Egger's tests. MAIN RESULTS: Fifteen RCTs were included (3253 IUI cycles, 2345 participants). No differences in OPR/LBR (OR 1.14, 95% CI 0.82-1.57, P = 0.44) and CPR (OR 1.28, 95% CI 0.97-1.69, P = 0.08) were found. Sensitivity and subgroup analyses did not provide statistical changes in pooled results. The body of evidence was rated as low (GRADE 2/4). No publication bias was detected. CONCLUSION: Pituitary block with GnRH antagonists does not improve OPR/LBR and CPR in women undergoing IUI cycles. TWEETABLE ABSTRACT: Pituitary block with GnRH antagonists does not improve the success of IUI cycles

Variabilidade e controle genético da resistência à seca de ponteiros em Eucalyptus na Região de Arapoti, PR.

Foram avaliadas espécies, procedências e progênies de Eucalyptus, para o caráter resistência à seca de ponteiros na Região de Arapoti - PR. As espécies que apresentaram maior grau de resistência foram E. dunnii e E. camaldulensis. Foram obtidas estimativas de herdabilidade na faixa de 93% entre espécies, 93% entre procedências de E. grandis, 75% entre progênies, 30% dentro de progênies e 28% entre indivíduos de E. grandis. Estimou-se ganho genético da ordem de 22% pela seleção entre e dentro de progênies. Entretanto, um único ciclo de seleção não foi suficiente para elevar a resistência a um nível adequado em E. grandis.bitstream/item/16990/1/Boletim_de_pesquisa06.pd

Solitons in 1+1 Dimensional Gauged Sigma Models

We study soliton solutions in 1+1 dimensional gauged sigma models, obtained by dimensional reduction from its 2+1 dimensional counterparts. We show that the Bogomol'nyi bound of these models can be expressed in terms of two conserved charges in a similar way to that of the BPS dyons in 3+1 dimensions. Purely magnetic vortices of the 2+1 dimensional completely gauged sigma model appear as charged solitons in the corresponding 1+1 dimensional theory. The scale invariance of these solitons is also broken because of the dimensional reduction. We obtain exact static soliton solutions of these models saturating the Bogomol'nyi bound.Comment: 21 pages, RevTeX, minor changes, version to appear in Physical Review

Seca dos ponteiros do eucalipto em Arapoti-PR.

Em 1988 e 1992, no municipio de Arapoti-PR, foram efetuados os primeiros registros da ocorrencia, em arvores de Eucalyptus grandis, de uma anomalia de crescimento denominada Seca dos Ponteiros de Eucalipto do Vale do Rio Doce (SPEVRD), apesar de que apenas a SPEA manifesta sintomas em plantas com idade inferior a sete meses e ocorre indistintamente em plantios de topos, encostas e baixadas. Com o presente trabalho procurou-se definir os componentes do mecanismo que desencadeia a SPEA, identificar respectivas interacoes e contribuicoes na manifestacao de sintomas. Pretendeu-se, assim, contribuir para a visao interativa e para o controle da SPEA e anomalias semelhantes. O trabalho foi conduzido em areas da INPACEL e, em laboratorios e casa de vegetacao da Embrapa/Florestas. As arvores com Spea reuniram sintomas, sinais e disturbios que evidenciaram ou sugeriram bloqueios na movimentacao e/ou na sintese de materia ou seja, disturbios no intercambio interno de agua, ions e hormonios, tais sejam: (a) injurias, intumecimentos, fissuras, cancros, anelamentos e oviposicao de insetos, atingindo tecidos vasculares, (b) granulos, estruturas de fungos e bacterias como agentes potenciais foliares, baixos de Ca, Mg e N incrementando o potencial injurioso do excesso de Cu e (d) como consequencias, dos eventos anteriores, geonastia dos ponteiros, brotacoes epicormicas, proliferacoes de ramos, malformacoes e manchas foliares. As analises estatisticas associaram a dispersao de insetos principalmente da ordem Thysanoptera..

Medical Legal Aspects of Telemedicine in Italy: Application Fields, Professional Liability and Focus on Care Services During the COVID-19 Health Emergency

Telemedicine services can be classified into the macro-categories of specialist Telemedicine, Tele-health and Tele-assistance. From a regulatory perspective, in Italy, the first provision dedicated to the implementation of Telemedicine services is represented by the Agreement between the Government and the Regions on the document bearing “Telemedicine—National guidelines,” approved by the General Assembly of the Superior Health Council in the session of 10th July 2012 and by the State Regions Conference in the session of 20th February 2014. Scientifically, several studies in the literature state that information and communication technologies have great potential to reduce the costs of health care services in terms of planning and making appropriate decisions that provide timely tools to patients. Another clear benefit is the equity of access to health care. The evolution of telemedicine poses a series of legal problems ranging from the profiles on the subject of authorization and accreditation to those concerning the protection of patient confidentiality, the definition and solution of which, in the absence of specific regulatory provisions, is mainly left to the assessment of compatibility of the practices adopted so far, with the general regulatory framework. In terms of professional liability, it is necessary to first clarify that the telemedicine service is comparable to any diagnostic-therapeutic health service considering that the telemedicine service does not replace the traditional health service, but integrates the latter to improve its effectiveness, efficiency and appropriateness

Wormhole cosmic strings

We construct regular multi-wormhole solutions to a gravitating $\sigma$ model in three space-time dimensions, and extend these solutions to cylindrical traversable wormholes in four and five dimensions. We then discuss the possibility of identifying wormhole mouths in pairs to give rise to Wheeler wormholes. Such an identification is consistent with the original field equations only in the absence of the $\sigma$-model source, but with possible naked cosmic string sources. The resulting Wheeler wormhole space-times are flat outside the sources and may be asymptotically Minkowskian.Comment: 17 pages, LaTeX, 4 figures (hard copy available on request

Alveolar fluid in acute respiratory distress syndrome promotes fibroblast migration: role of platelet-derived growth factor pathway

OBJECTIVES: Fibroblast migration is an initiating step in fibroproliferation; its involvement during acute lung injury and acute respiratory distress syndrome remains poorly understood. The aims of this study were: 1) to determine whether bronchoalveolar lavage fluids from patients with acute lung injury/acute respiratory distress syndrome modulate lung fibroblast migration; 2) to assess lung fibroblast migration\u27s clinical relevance; and 3) to evaluate the role of the platelet-derived growth factor pathway in this effect. DESIGN: Prospective cohort study. SETTING: Three intensive care units of a large tertiary referral center. PATIENTS: Ninety-three ventilated patients requiring bronchoalveolar lavage fluids were enrolled (48 with acute respiratory distress syndrome, 33 with acute lung injury, and 12 ventilated patients without acute lung injury/acute respiratory distress syndrome). INTERVENTIONS: After bronchoalveolar lavage fluids collection during standard care, the patients were followed up for 28 days and clinical outcomes were recorded. Migration assays were performed by using a Transwell model; bronchoalveolar lavage fluids platelet-derived growth factor and soluble platelet-derived growth factor receptor-alpha were characterized by Western blot and measured by ELISA. MEASUREMENTS AND MAIN RESULTS: Most of the bronchoalveolar lavage fluids inhibited basal fibroblast migration. Bronchoalveolar lavage fluids chemotactic index increased with severity of lung injury (28% in patients without acute lung injury/acute respiratory distress syndrome and with acute lung injury vs. 91% in acute respiratory distress syndrome patients; p = .016). In acute lung injury/acute respiratory distress syndrome patients, inhibition of basal fibroblast migration by bronchoalveolar lavage fluids below 52% was independently associated with a lower 28-day mortality (odds ratio [95% confidence interval] 0.313 [0.10-0.98], p = .046). Platelet-derived growth factor-related peptides and soluble platelet-derived growth factor-Ralpha were detected in all bronchoalveolar lavage fluids from acute lung injury/acute respiratory distress syndrome patients. The effect of bronchoalveolar lavage fluids stimulating migration was inhibited by a specific platelet-derived growth factor receptor inhibitor (AG1296). Bronchoalveolar lavage fluids inhibiting migration reversed the effect of rh-platelet-derived growth factor-BB and reduced by 40% the binding of 125I-platelet-derived growth factor-BB to fibroblast cell surface in favor of a role for platelet-derived growth factor-sRalpha. CONCLUSIONS: : Together, our results suggest that during acute lung injury, fibroblast migration is modulated by bronchoalveolar lavage fluids through a platelet-derived growth factor/platelet-derived growth factor-sRalpha balance. Migration is associated with clinical severity and patient 28-day mortality