Post-selection and return of foraged material by Acromyrmex subterraneus brunneus (Hymenoptera: Formicidae)

Two colonies of Acromyrmex subterraneus brunneus Forel (Hymenoptera: Formicidae) were studied regarding their behavior during cultivation of the fungus garden to determine a) the existence of post-selection of foraged material by the workers, and b) if present, the mechanism of this discrimination and how this material is returned. Many studies on plant processing by leaf-cutting ants have been carried out, but none of them has investigated the decision-making process of workers in the case of erroneous food selection. For this purpose, material with different degrees of moisture and hardness (floral sponge, polystyrene, plastic and clay) were individually offered to the colonies and the tasks performed by the different size categories were carefully recorded. Three tasks, i.e., foraging, cultivation of the fungus garden and return of the foraged material, were studied and subdivided into 14 subtasks. Analysis of all inert materials as a whole showed the presence of post-selection of foraged material through the return of material inadequate for the workers and the fungus. Discrimination of the inert material was observed at the time of shredding, probably based on parameters such as physical resistance to cutting and moisture content. A. s. brunneus workers showed flexibility in their activities during substrate processing. The observed post-selection of foraged material provides strong evidence for the cognitive abilities of worker ants and of the colony as a whole. Polymorphism and a complex society represent vital characteristics for the ecological success of this species.

The effect of trail length on task partitioning in three Acromyrmex species (Hymenoptera: Formicidae)

By comparing the behavior of three Acromyrmex (Hymenoptera, Formicidae) species during foraging on artificial trails of different lengths, we observed the occurrence of task partitioning and its relation to the food distance from the nest. Task partitioning was verified by leaf cache formation along the trail and leaf direct transferring among workers. There was significant difference between the number of leaf fragments carried directly to the fungus chamber and those transferred direct or indirectly, via cache, depending upon the trail length. Task partitioning could be a strategy used by leaf-cutting ants that allows the workers to use food sources far from their nests.

The effect of plant diversity on fungus garden development and foraging behavior of leaf-cutting ants (Hymenoptera: Formicidae)

The leaf-cutting ants forage a wide variety of plant species, used for symbiotic fungus cultivation. To better understand this tripartite complex interaction, 24 colonies of Acromyrmex subterraneus brunneus were conditioned for 4 months to 6 different plants (Citrus spp., Ligustrum spp., Acalypha spp., Eucalyptus spp., Alchornea triplinervia, Melia spp.), to verify the influence of conditioning on foraging behavior of workers. The effect of plants on symbiotic fungus development was studied separately, through macerated plants in Agar and culture medium A as the control. During foraging, workers presented polyphagic foraging behavior, refusing the plants to which they were conditioned. The selection of plants is not correlated with the plant substrate that promotes good development of symbiotic fungus. Such results demonstrate the importance of plant diversity for fungus garden maintenance.

Foraging Behavior and Subtask Hierarchical Structure in Acromyrmex spp. (Hymenoptera: Formicidae)

This study considers the function and complexity of tasks during foraging of three Acromyrmex species. Foraging was classified as a team task composed of 2 or 3 processes: recruitment, selection, and collection. Each process was subdivided into different subtasks. Points were attributed to subtasks considering their hierarchical level to compare the complexity of foraging among species. Total scores obtained were 19 for A. balzani and 14 for A. crassispinus and A. rugosus, indicating different degrees of social complexity for grass-cutting and leaf-cutting ant species. Acromyrmex balzani, a grass-cutting ant species, shows a behavioral repertoire composed of more variable subtasks during foraging.

Thermally developing forced convection of non-Newtonian fluids inside elliptical ducts

Laminar-forced convection inside tubes of various cross-section shapes is of interest in the design of a low Reynolds number heat exchanger apparatus. Heat transfer to thermally developing, hydrodynamically developed forced convection inside tubes of simple geometries such as a circular tube, parallel plate, or annular duct has been well studied in the literature and documented in various books, but for elliptical duct there are not much work done. The main assumptions used in this work are a non-Newtonian fluid, laminar flow, constant physical properties, and negligible axial heat diffusion (high Peclet number). Most of the previous research in elliptical ducts deal mainly with aspects of fully developed laminar flow forced convection, such as velocity profile, maximum velocity, pressure drop, and heat transfer quantities. In this work, we examine heat transfer in a hydrodynamically developed, thermally developing laminar forced convection flow of fluid inside an elliptical tube under a second kind of a boundary condition. To solve the thermally developing problem, we use the generalized integral transform technique (GITT), also known as Sturm-Liouville transform. Actually, such an integral transform is a generalization of the finite Fourier transform, where the sine and cosine functions are replaced by more general sets of orthogonal functions. The axes are algebraically transformed from the Cartesian coordinate system to the elliptical coordinate system in order to avoid the irregular shape of the elliptical duct wall. The GITT is then applied to transform and solve the problem and to obtain the once unknown temperature field. Afterward, it is possible to compute and present the quantities of practical interest, such as the bulk fluid temperature, the local Nusselt number, and the average Nusselt number for various cross-section aspect ratios.

Effect of ceramic surface treatment on the microtensile bond strength between a resin cement and an alumina-based ceramic

Purpose: The objective of this study was to test the following hypothesis: the silica coating on ceramic surface increases the bond strength of resin cement to a ceramic. Materials and Methods: In-Ceram Alumina blocks were made and the ceramic surface was treated: G1 - sandblasting with 110-μm aluminum oxide particles; G2 - Rocatec System: tribochemicai silica coating (Rocatec-Pre powder + Rocatec-Plus powder + Rocatec-Sil); G3 - CoJet System: silica coating (CoJet-Sand) + ESPE-Sil. The ceramic blocks were cemented to composite blocks with Panavia F resin cement (under a load of 750 g/1 min). The cemented blocks were stored in distilled water at 37°C for 7 days and sectioned along the x and y axes with a diamond disk. Samples with an adhesive area of ca 0.8 mm 2 (n = 45) were obtained. The samples were attached to an adapted device for the microtensile test, which was performed in a universal testing machine (EMIC) at a crosshead speed of 1 mm/min. Results: The obtained results were submitted to ANOVA and Tukey's test. Mean values of tensile strength (MPa) and standard deviation values were: (G1) 16.8 ± 3.2; (G2) 30.6 ± 4.5; (G3) 33.0 ± 5.0. G2 and 63 presented greater tensile strength than G1. There was no significant difference between G2 and G3. All the failures took place at the ceramic/resin cement interface. Conclusion: The silica coating (Rocatec or CoJet systems) of the ceramic surface increased the bond strength between the Panavia F resin cement and alumina-based ceramic.

Effect of surface treatments on the resin bond to zirconium-based ceramic

Purpose: This study tested the hypothesis that the tribochemical silica coating on ceramic surfaces increases the bond strength of resin cement to a glass-infiltrated zirconium-based ceramic. Materials and Methods: Fifteen blocks of In-Ceram Zirconia from CEREC InLab (5 per group) and 15 composite blocks (Z-250) 5 mm x 5 mm x 4 mm were made. The ceramic surfaces were polished, and the blocks were divided into three groups: (1) airborne abrasion with 110-μm aluminum oxide particles; (2) Rocatec system, tribochemical silica coating; and (3) CoJet system, tribochemical silica coating. The ceramic blocks were cemented to the composite blocks using Panavia F according to the manufacturer's specifications. All samples were stored in 37°C distilled water for 7 days and later sectioned in two axes using a diamond disk under cooling to obtain specimens with a cross-sectional area of approximately 1 mm2 (n = 45). Each specimen was then attached with cyanoacrylate glue to an adapted device for the microtensile test, which was carried out on a universal testing machine. Results: The results were subjected to ANOVA and Tukey's test. Group 2 (23.0 ± 6.7 MPa) and group 3 (26.8 ± 7.4 MPa) showed greater bond strength than group 1 (15.1 ± 5.3 MPa). There was no significant difference between groups 2 and 3. All failures were in the adhesive zone. Conclusion: The hypothesis was confirmed - the tribochemical systems increased the bond strength between Panavia F and In-Ceram Zirconia.

Evaluation of the flexural strength of carbon fiber-, quartz fiber-, and glass fiber-based posts

This study investigated the flexural strength of eight fiber posts (one carbon fiber, one carbon/quartz fiber, one opaque quartz fiber, two translucent quartz fiber, and three glass fiber posts). Eighty fiber posts were used and divided into eight groups (n = 10): G1: C-POST (Bisco); G2: ÆSTHETI-POST (Bisco); G3: ÆSTHETI-PLUS (Bisco); G4: LIGHT-POST (Bisco); G5: D.T. LIGHT-POST (Bisco); G6: PARAPOST WHITE (Coltene); G7: FIBERKOR (Pentron); G8: REFORPOST (Angelus). All of the samples were tested using the three-point bending test. The averages obtained were submitted to the ANOVA and to Tukey's test (p < 0.05). The mean values (MPa) of the groups ÆSTHETI-POST - carbon/ quartz fiber post (Bisco) and ÆSTHETI-PLUS - quartz fiber post (Bisco) were statistically similar and higher than the mean values of the other groups. The mean values of the groups C-POST - carbon fiber post (Bisco), LIGHT-POST - translucent quartz fiber post (Bisco), D.T. LIGHT-POST - double tapered translucent quartz fiber post (Bisco), PARAPOST WHITE - glass fiber post (Coltene) and FIBREKOR - glass fiber post (Pentron) were similar and higher than the group REFORPOST - glass fiber post (Angelus). Copyright © 2005 by the American Association of Endodontists.

Isolated Richter's syndrome in central nervous system: Case report

Diffuse large cell non Hodgkin's lymphoma associated with chronic lymphoid leukemia (CLL), or Richter's syndrome, is a rare and serious complication. Isolated Richter's syndrome in the central nervous system is very rare; only 12 cases have been reported. We describe a 74-year-old patient with diffuse large cell non Hodgkin's lymphoma in the right frontal region with the appearance of multiform glioblastoma.

Investigação de Intrusão de Água Salgada em Aqüífero Superficial a Partir de Medidas de Resistividade Elétrica

A site investigation program was carried out to detect salt-water intrusions in a shallow sedimentary aquifer based on electrical resistivity measurements. The site is located close to Paranaguá harbor, in the Paraná State, Brasil. At this site, high chloride concentration contaminated shallow water wells used to supply water for local industries. The site investigation program included a fieldwork, dipole-dipole electrical profiling, resistivity piezocone tests, physical-chemical analysis of sampled water and interpretation of borehole logs. The resistivity piezocone tests provided two simultaneous information; the soil stratigraphy at a very detailed level and a quasi-continuous resistivity profile. Both information adequately complemented dipole-dipole electrical profiling test data. The integration of all test data allowed identifying the contaminated areas as well as guided the location of new water wells to be installed in this area.

Liposomal daunorubicin and dexamethasone as a treatment for multiple myeloma - The DD protocol

Context and Objective: Lipasomial daunorubicin has been used to treat hematological malignancies, including multiple myelomo (MM). The goal was to evaluate efficacy, side-effects and toxicity of liposomal daunorubicin and dexamethasone (DD Protocol). Design and Setting: Prospective study of Sírio-Libonês, São Camilo, Brasil and Alemão Oswaldo Cruz hospitals. Methods: Twenty consecutive patients with active MM received four cycles of liposomal daunorubicin intravenously for two hours (25-30 mg/m 2/day) on three consecutive days per month, with oral dexamethasone, (10 mg every six hours) on four consecutive days three times a month. Results: The male/female ratio was 1:1 and median age 60. Nine patients were stage IIA, ten IIIA and one IIIB. The median from diagnosis to starting DD was 13 months. All patients received four cycles, except one. Fifteen had already received chemotherapy before DD. Responses of > 50% reduction in serum monoclonal paraprotein were observed in six patients after first cycle (30%), six after second (30%) and four after third (20%), while four (20%) did not obtain this. Initially, 17 patients (85%) had anemia: 12 (70%) achieved correction. Progressive disease was observed in three patients (15%), while one had minimal response, four (20%) partial and 12 (60%) complete. Hemotologlical toxicity was acceptable: three patients (15%) had neutrophils < 1,000/mm 3; none had thrombocyfopenia. Gastrointestinal toxicity was mild: nausea (10%), anorexio (15%) and no vomiting. Conclusions: This treatment has mild toxicity and good response rate. It may therefore be feasible before autologous bone marraw transplantation.

Effect of silica coating on flexural strength of fiber posts

Purpose: Fiber-reinforced composite (FRC) posts can be air-abraded to obtain good attachment to the resin cement. This study tested the effect of silica coating on the flexural strength of carbon, opaque, and translucent quartz FRC posts. Materials and Methods: Six experimental groups of FRC posts (n = 10 per group) were tested, either as received from the manufacturer or after chairside silica coating (30-μm CoJet-Sand). Results: There was no significant difference in the flexural strength of nonconditioned (504 to 525 MPa) and silica-coated (514 to 565 MPa) specimens (P > .05) (analysis of variance). The type of post did have a significant effect on flexural strength (P < .05). Conclusion: Chairside silica coating did not affect the flexural strength of both carbon and quartz FRC posts.

Fatigue resistance of the bond of a glass-infiltrated alumina ceramic to human dentin

Purpose: To evaluate the fatigue resistance of the bond between dentin and glass-infiltrated alumina ceramic, using different luting protocols. Materials and Methods: The null hypothesis is that the fatigue resistance varies with the luting strategy. Forty blocks of In-Ceram Alumina were prepared, and one surface of each block was abraded with 110-μm aluminum oxide particles. Then, the blocks were luted to flat dentin surfaces of 40 human third molars, using 4 different luting strategies (luting system [LS]/ceramic surface conditioning [CSC]) (n=10): (G1) [LS] RelyX-Unicem/[CSC] airborne abrasion with 110-μm Al2O3 particles; (G2) [LS] One-Step + Duo-Link (bis-GMA-based resin)/[CSC] etching with 4% hydrofluoric acid + silane agent; (G3) [LS] ED-Primer + Panavia F (MDP-based resin)/[CSC] Al2O 3; (G4) [LS] Scotchbond1+RelyX-ARC (bis-GMA-based resin)/[CSC] chairside tribochemical silica coating (air abrasion with 30-μm SiO x particles + silane). After 24 h of water storage at 37°C, the specimens were subjected to 106 fatigue cycles in shear with a sinusoidal load (0 to 21 N, 8 Hz frequency, 37°C water). A fatigue survivor score was given, considering the number of the fatigue cycles until fracture. The failure modes of failed specimens were observed in a SEM. Results: G3 (score = 5.9, 1 failure) and G4 (score = 6, no failures) were statistically similar (p = 0.33) and had significantly higher fatigue resistance than G1 (score = 3.9, 5 failures) and G2 (score = 3.7, 6 failures) (p < 0.03). SEM analysis of fractured specimens of G1 and G2 showed that almost all the failures were between ceramic and cement. Conclusion: The MDP-based resin cement + sandblasting with Al2O3 particles (G3) and bis-GMA-based resin cement + tribochemical silica coating (G4), both using the respective dentin bonding systems, were the best luting protocols for the alumina ceramic. The null hypothesis was confirmed.

Bond strength of a resin cement to high-alumina and zirconia-reinforced ceramics: The effect of surface conditioning

Purpose: The aim of this study was to evaluate the effect of two surface conditioning methods on the microtensile bond strength of a resin cement to three high-strength core ceramics: high alumina-based (In-Ceram Alumina, Procera AllCeram) and zirconia-reinforced alumina-based (In-Ceram Zirconia) ceramics. Materials and Methods: Ten blocks (5 ×6 × 8 mm) of In-Ceram Alumina (AL), In-Ceram Zirconia (ZR), and Procera (PR) ceramics were fabricated according to each manufacturer's instructions and duplicated in composite. The specimens were assigned to one of the two following treatment conditions: (1) airborne particle abrasion with 110-μm Al2O3 particles + silanization, (2) silica coating with 30 μm SiOx particles (CoJet, 3M ESPE) + silanization. Each ceramic block was duplicated in composite resin (W3D-Master, Wilcos, Petrópolis, RJ, Brazil) using a mold made out of silicon impression material. Composite resin layers were incrementally condensed into the mold to fill up the mold and each layer was light polymerized for 40 s. The composite blocks were bonded to the surface-conditioned ceramic blocks using a resin cement system (Panavia F, Kuraray, Okayama, Japan). One composite resin block was fabricated for each ceramic block. The ceramic-composite was stored at 37°C in distilled water for 7 days prior to bond tests. The blocks were cut under water cooling to produce bar specimens (n = 30) with a bonding area of approximately 0.6 mm2. The bond strength tests were performed in a universal testing machine (crosshead speed: 1 mm/min). Bond strength values were statistically analyzed using two-way ANOVA and Tukey's test (≤ 0.05). Results: Silica coating with silanization increased the bond strength significantly for all three high-strength ceramics (18.5 to 31.2 MPa) compared to that of airborne particle abrasion with 110-μm Al2O3 (12.7-17.3 MPa) (ANOVA, p < 0.05). PR exhibited the lowest bond strengths after both Al2O3 and silica coating (12.7 and 18.5 MPa, respectively). Conclusion: Conditioning the high-strength ceramic surfaces with silica coating and silanization provided higher bond strengths of the resin cement than with airborne particle abrasion with 110-μm Al2O3 and silanization.

The role of workers in transferring queen substances and the differences between worker castes in the leaf-cutting ant, Acromyrmex subterraneus brunneus (Hymenoptera: Formicidae)

The present study focused on the relationship between the queen and workers in Acromyrmex subterraneus brunneus colonies mediated by the possible transfer of substances from the fertile to the sterile caste. The queens were submitted to different situations of physical limitation, i.e., they were kept isolated in cages with holes that only permitted the entry of workers but left the queen isolated. A tracer (water-soluble dye) was applied to the pronotum and gaster of the queen and its dispersal among workers was analyzed. The results demonstrated that the minor sub caste (0.7-0.9 mm) passed on the dye through allogrooming and self-grooming, or transferred the dye through trophallaxis to the major sub caste (1.2-2.0 mm) when they were not in direct contact with the queen. These findings indicate the communication and probable transfer of substances from the queen to the workers, as well as a substance transfer between workers.