Ants Can Learn to Forage on One-Way Trails

The trails formed by many ant species between nest and food source are two-way roads on which outgoing and returning workers meet and touch each other all along. The way to get back home, after grasping a food load, is to take the same route on which they have arrived from the nest. In many species such trails are chemically marked by pheromones providing orientation cues for the ants to find their way. Other species rely on their vision and use landmarks as cues. We have developed a method to stop foraging ants from shuttling on two-way trails. The only way to forage is to take two separate roads, as they cannot go back on their steps after arriving at the food or at the nest. The condition qualifies as a problem because all their orientation cues-chemical, visual or any other - are disrupted, as all of them cannot but lead the ants back to the route on which they arrived. We have found that workers of the leaf-cutting ant Atta sexdens rubropilosa can solve the problem. They could not only find the alternative way, but also used the unidirectional traffic system to forage effectively. We suggest that their ability is an evolutionary consequence of the need to deal with environmental irregularities that cannot be negotiated by means of excessively stereotyped behavior, and that it is but an example of a widespread phenomenon. We also suggest that our method can be adapted to other species, invertebrate and vertebrate, in the study of orientation, memory, perception, learning and communication.

Contuse lesion of the rat spinal cord of moderate intensity leads to a higher time-dependent secondary neurodegeneration than severe one - An open-window for experimental neuroprotective interventions

Secondary neurodegeneration takes place in the surrounding tissue of spinal cord trauma and modifies substantially the prognosis, considering the small diameter of its transversal axis. We analyzed neuronal and glial responses in rat spinal cord after different degree of contusion promoted by the NYU Impactor. Rats were submitted to vertebrae laminectomy and received moderate or severe contusions. Control animals were sham operated. After 7 and 30 days post surgery, stereological analysis of Nissl staining cellular profiles showed a time progression of the lesion volume after moderate injury, but not after severe injury. The number of neurons was not altered cranial to injury. However, same degree of diminution was seen in the caudal cord 30 days after both severe and moderate injuries. Microdensitometric image analysis demonstrated a microglial reaction in the white matter 30 days after a moderate contusion and showed a widespread astroglial reaction in the white and gray matters 7 days after both severities. Astroglial activation lasted close to lesion and in areas related to Wallerian degeneration. Data showed a more protracted secondary degeneration in rat spinal cord after mild contusion, which offered an opportunity for neuroprotective approaches. Temporal and regional glial responses corroborated to diverse glial cell function in lesioned spinal cord. (C) 2007 Elsevier Ltd. All rights reserved.

Contribution to dynamic characteristics of the cutting temperature in the drilling process considering one dimension heat flow

The machining of hardened steels has always been a great challenge in metal cutting, particularly for drilling operations. Generally, drilling is the machining process that is most difficult to cool due to the tool`s geometry. The aim of this work is to determine the heat flux and the coefficient of convection in drilling using the inverse heat conduction method. Temperature was assessed during the drilling of hardened AISI H13 steel using the embedded thermocouple technique. Dry machining and two cooling/lubrication systems were used, and thermocouples were fixed at distances very close to the hole`s wall. Tests were replicated for each condition, and were carried out with new and worn drills. An analytical heat conduction model was used to calculate the temperature at tool-workpiece interface and to define the heat flux and the coefficient of convection. In all tests using new and worn out drills, the lowest temperatures and decrease of heat flux were observed using the flooded system, followed by the MQL, considering the dry condition as reference. The decrease of temperature was directly proportional to the amount of lubricant applied and was significant in the MQL system when compared to dry cutting. (C) 2011 Elsevier Ltd. All rights reserved.

Identification and chromosomal localization of one locus of Leishmania (L.) major related with resistance to itraconazole

Ergosterol is an important compound responsible to maintain integrity and fluidity of Leishmania spp. membranes. Starting from an overexpression/selection method, our group has isolated and mapped nine different loci of Leishmania (L.) major related to resistance against two inhibitors of the ergosterol biosynthesis pathway, terbinafine (TBF) and itraconazole (ITZ). Individual functional analysis after overexpression induction of these loci in the presence of TBF and/or ITZ [or the ITZ analog ketoconazole (CTZ)] have shown low but significant levels of resistance after transfection into L. major wild-type parasites. In this work, we have shown the insert mapping and chromosomal identification of one of these loci (cosItz2). Functional analysis experiments associated with chromosomal localization by comparison at genomic database allowed us to identify two prospective gene-protein systems not related to the ergosterol biosynthesis and capable to confer wild-type cells resistance to ITZ-CTZ after transfection. We expected that this approach can open new insights for a better understanding of mechanisms of ITZ-CTZ action and resistance in Leishmania resulting in new strategies for the leishmaniasis treatment.

Evaluation of interventions to reduce catheter-associated bloodstream infection: Continuous tailored education versus one basic lecture

Background: This study evaluated the impact of 2 models of educational intervention on rates of central venous catheter-associated bloodstream infections (CVC-BSIs). Methods: This was a prospective observational study conducted between January 2005 and June 2007 in 2 medical intensive care units (designated ICU A and ICU B) in a large teaching hospital. The study was divided into in 3 periods: baseline (only rates were evaluated), preintervention (questionnaire to evaluate knowledge of health care workers [HCWs] and observation of CVC care in both ICUs), and intervention (in ICU A, tailored, continuous intervention; in ICU B, a single lecture). The preintervention and intervention periods for each ICU were compared. Results: During the preintervention period, 940 CVC-days were evaluated in ICUA and 843 CVC-days were evaluated in ICU B. During the intervention period, 2175 CVC-days were evaluated in ICUA and 1694 CVC-days were evaluated in ICU B. Questions regarding CVC insertion, disinfection during catheter manipulation, and use of an alcohol-based product during dressing application were answered correctly by 70%-100% HCWs. Nevertheless, HCWs` adherence to these practices in the preintervention period was low for CVC handling and dressing, hand hygiene (6%-35%), and catheter hub disinfection (45%-68%). During the intervention period, HCWs` adherence to hand hygiene was 48%-98%, and adherence to hub disinfection was 82%-97%. CVC-BSI rates declined in both units. In ICUA, this decrease was progressive and sustained, from 12CVC-BSIs/1000 CVC-days at baseline to 0 after 9 months. In ICU B, the rate initially dropped from 16.2 to 0 CVC-BSIs/1000 CVC-days, but then increased to 13.7 CVC-BSIs/1000 CVC-days. Conclusion: Personal customized, continuous intervention seems to develop a ""culture of prevention"" and is more effective than single intervention, leading to a sustained reduction of infection rates.

Hantavirus infection associated to a staphylococcal sepsis. Report of one case

We report a previously healthy 36-year-old male who developed a pulmonary syndrome caused by Hantavirus infection He was admitted to an intensive care unit in shock awl respiratory failure and died four hours after admission. Blood cultures were positive for Staphylococcus aureus This patient could be an index case that shows, for the first time, an association of Hantavirus Pulmonary Syndrome with Staphylococcus nitwits infection similar to what happens with other viruses (Rev Med Chile 2010, 138: 338-340).

A single amino acid substitution in one of the lipases of Aspergillus nidulans confers resistance to the antimycotic drug undecanoic acid

A plausible approach to evaluate the inhibitory action of antifungals is through the investigation of the fungal resistance to these drugs. We describe here the molecular cloning and initial characterization of the A. nidulans lipA gene, where mutation (lipA1) conferred resistance to undecanoic acid, the most fungitoxic fatty acid in the C(7:0)-C(18:0) series. The lipA gene codes for a putative lipase with the sequence consensus GVSIS and WIFGGG as the catalytic signature. Comparison of the wild-type and LIP1 mutant strain nucleotide sequences showed a G -> A change in lipA1 allele, which results in a Glu(214) -> Lys substitution in LipA protein. This ionic charge change in a conserved LipA region, next to its catalytic site, may have altered the catalytic properties of this enzyme resulting in resistance to undecanoic acid.

Increased arterial stiffness in nonobese women with polycystic ovary syndrome (PCOS) without comorbidities: one more characteristic inherent to the syndrome?

Background Polycystic ovary syndrome (PCOS) is associated with adverse metabolic effects. Some cardiovascular disease (CVD) risk markers are increased in women with PCOS. However, early markers of atherosclerosis are also associated with obesity and insulin resistance, which are related to PCOS. These markers may result either directly from PCOS or indirectly as a consequence of the comorbidities associated with the syndrome. Context To assess the presence of early CVD markers in young, nonobese women with PCOS. Patients Forty women with PCOS and 50 healthy women with regular menstrual cycles, matched for age and body mass index (BMI). Measurements The following CVD markers were assessed by ultrasonography: common carotid artery (CCA) stiffness index (beta), distensibility and intima-media thickness (IMT), and brachial artery flow-mediated dilatation (FMD). Inflammatory markers, including interleukin (IL)-6, tumour necrosis factor (TNF)-alpha, homocysteine, C-reactive protein (CRP), glycaemia, lipid profile and insulin, were also assessed. Results CCA beta was higher in PCOS than in control women (3 center dot 72 +/- 0 center dot 96 vs. 3 center dot 36 +/- 0 center dot 96, P = 0 center dot 04) and CCA distensibility was lower (0 center dot 31 +/- 0 center dot 08 vs. 0 center dot 35 +/- 0 center dot 09 mmHg(-1), P = 0 center dot 02). Waist circumference, total testosterone and the Free Androgen Index (FAI) were higher in PCOS patients than in controls (78 center dot 2 +/- 10 center dot 0 vs. 71 center dot 5 +/- 7 center dot 2 cm, P = 0 center dot 001; 88 center dot 1 +/- 32 center dot 4 vs. 57 center dot 1 +/- 21 center dot 2 ng/dl, P < 0 center dot 01; 12 center dot 7 +/- 15 center dot 7%vs. 4 center dot 7 +/- 2 center dot 3%, P < 0 center dot 01, respectively), while SHBG was reduced (37 center dot 9 +/- 19 center dot 1 vs. 47 center dot 8 +/- 18 center dot 3 nmol/l, P = 0 center dot 01). The remaining variables did not differ between the groups. Conclusions Young women with PCOS exhibit changes in vascular elasticity even in the absence of classical risk factors for CVD, such as hypertension and obesity.

Microtensile vs Microshear Bond Strength of All-in-One Adhesives to Unground Enamel

Purpose To determine the bond strength to unground enamel of all in one adhesives in comparison with an etch and rinse system and to compare the reliability of microtensile and microshear methods in providing such measurements Materials and Methods The bonding procedure was performed on enamel of 64 extracted molars The tested all in one adhesives were Bond Force (Tokuyama), AdheSE One (Ivoclar Vivadent) and Xeno V (Dentsply) Prime&Bond NT (Dentsply) served as control Microtensile specimens were obtained from 4 teeth per group Twelve teeth per group were used for microshear testing Microtensile specimens that failed prior to testing were included in statistical calculations, they were assigned the lowest value measured in the respective group Failure modes were observed under light microscope and classified (cohesive within substrates, adhesive mixed) Statistically significant differences in bond strength were assessed among the adhesives within each testing method and between microshear and microtensile data for each adhesive Failure mode distributions were compared using the chi square test Results All in-one adhesives had similar microshear and microtensile bond strengths In both testing methods, the etch and rinse system achieved the strongest bond For all adhesives significantly higher bond strengths were measured with the microshear test In microtensile testing specimens bonded with the etch and rinse adhesive exhibited a significantly different distribution of failure modes The coefficients of variation were extremely high for microtensile bond strength data, particularly of all in one adhesives Conclusion The adhesive potential to intact enamel of recently introduced all in-one adhesives was inferior to that of an etch and rinse system When testing bond strength to enamel of all in one adhesives, microshear testing may be a more accurate method than microtensile

Reply to comment on `Integrable Kondo impurity in one-dimensional q-deformed t - J models

This is a reply to the comment by P Schlottmann and A A Zvyagin.

Peppers, Don e Rogers, Martha, One to One B2B, Currency books, Double Day, Radon House Inc, Copyright, 2001

Há muito que se fala do fim do Marketing tal como o conhecemos. A segmentação cada vez maior de mercados e clientes e a importância da customização, tornaram obsoletas a maior parte das abordagens do marketing de massas. A evolução da economia e das TI (tecnologias da informação) e as consequentes alterações que esse processo implicou na cadeia de valor das empresas, nomeadamente das organizações de grande dimensão, fez com que o B2C –Business to Customer – tenha deixado de fazer sentido para estas empresas. O advento da World Wide Web e o impacto que as tecnologias «interactivas» têm actualmente sobre a economia, provocou grandes alterações nas relações entre as organizações e os seus clientes. Ao Marketing de massas sucedeu-se a relação individualizada cliente a cliente, emergente no B2B – Business to Business –one to one, onde mais importante do que as vendas é o relacionamento com o cliente que assume particular importância, nomeada mente em ordem à sua transição para outras zonas de negócio, como a Internet.

Antibody response to heat-inactivated hepatitis B vaccine (CLB-3mg) in hemodialysis patients and occupational risk personnel: a one year follow-up

Immune response against hepatitis B vaccine (CLB 3mg) was evaluated in 59 hemodialysis patients and 20 occupational risk personnel. Seroconversion was induced in 52.5% and 70.0% respectively. Twelve months after the first dose, 37.5% of patients and 60.0% of occupational risk personnel had detectable anti-HBs level. Antibody level was expressed in sample ratio units (SRU). Considering only the responders, in the patients group 38.7% had a low anti-HBs response (2.1-9.9 SRU) 32.3% a medium response (10-99.9 SRU) and 29.0% a high response (>100 SRU) while in occupational risk personnel these values were 14.3%, 64.3% and 21.4% respectively. The authors suggest the use of HBV vaccines with more elevated HBsAg concentration or a reinforced immunization schedule to improve the anti-HBs response not only for patients but also for healthy persons.