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Electric reduction furnaces cannot be fed fines in the production of manganese ferroalloy as they hinder gas permeability. Thus, agglomeration techniques can be used to minimize the environmental and economic impacts of storing fines. Among these techniques, briquetting is advantageous because it allows for cold agglomeration of the particles and is flexible in terms of particle sizes. Therefore, this work aimed to develop self-reductor briquettes composed of ore manganese fines, dust ferromanganese, charcoal fines, and three different binders. The compaction pressure, curing time, and % binder were optimized to enhance briquette strength through a multivariate experimental design consisting of a screening study using a 23 full factorial design followed by response surface methodology with a spherical central composite design. The results were assessed by analysis of variance, and a regression model was established. The study found that briquettes elaborated with bentonite exhibited an optimized compressive strength of 4.02 MPa, achieved with a compaction pressure of 67.55 MPa and 12.71% bentonite. For briquettes elaborated with pregelatinized starch, a compressive strength of 7.04 MPa was obtained with a compaction pressure of 67.52 MPa, a curing time of 19.51 days, and 8.07% pregelatinized starch. For briquettes agglomerated using slaked lime and molasses, an optimized compaction pressure of 27.09 MPa and a curing time of 23.27 days resulted in a compressive strength of 1.63 MPa. These results suggest that briquettes containing bentonite and pregelatinized starch are feasible substitutes for lump ore in electric furnaces.

The objective of the present study was to evaluate the effect of treatment with prostaglandin F2α (PGF2α) at the beginning of the protocol for ovulation synchronization on follicular dynamics in Bos indicus (Gyr; n=11), Bos taurus (Holstein Black and White, HBW; n=10), and crossbred animals (Gyr x HBW; n=12). On a random day of the estrous cycles (day 0, D0), the animals received 2.0 mg estradiol benzoate (EB) intramuscularly plus an intravaginal progesterone (P4) device, which was maintained for 8 days (day 8, D8). Half the heifers of each group received a dose of 25 mg PGF2α intramuscularly at the time of insertion of the intravaginal P4 device. When the intravaginal device was removed (D8), all animals received another dose of 25 mg PGF2α intramuscularly, followed by intramuscular injection of 1.0 mg EB 24 h later (day 9, D9). Ultrasonographic evaluations were performed at intervals of 24 hours from D0 to D8 and at intervals of 12 hours from removal of the P4 device to 96 hours thereafter. Samples were collected on days 0, 3, 6, 8, 10 and 22 for the measurement of P4. The mean maximum diameter of the dominant follicle (DF) was smaller (P=0.01) in Gyr heifers (10.0 ± 0.8 mm) than in Gyr x HBW (13.0 ± 0.6 mm) or HBW (12.5 ± 0.8 mm). Furthermore, treatment with PGF2α on D0 increased (P=0.02) the maximum diameter of DF (12.9 ± 0.5 vs. 10.9 ± 0.7 mm) in the three genetic groups evaluated. The growth rate of the DF was lower (P=0.008) in Gyr heifers (0.8 ± 0.1 mm/day) than in crossbred heifers (1.3 ± 0.1 mm/day) or HBW (1.2 ± 0.1 mm/day). Heifers of the three genetic groups treated with PGF2α on D0 had higher (P=0.002) growth rates of DF (1.3 ± 0.1 vs. 0.9 ± 0.1 mm/day). The ovulation rate was lower (P=0.02) in Gyr heifers (36.4%) than in crossbred heifers (83.3%), but did not differ from HBW heifers (70.0%). However, higher (P

Two experiments were conducted to investigate the effects of equine chorionic gonadotropin (eCG) at progestin removal and gonadotropin-releasing hormone (GnRH) at timed artificial insemination (TAI) on ovarian follicular dynamics (Experiment 1) and pregnancy rates (Experiment 2) in suckled Nelore (Bos indicus) cows. Both experiments were 2 × 2 factorials (eCG or No eCG, and GnRH or No GnRH), with identical treatments. In Experiment 1, 50 anestrous cows, 134.5 ± 2.3 d postpartum, received a 3 mg norgestomet ear implant sc, plus 3 mg norgestomet and 5 mg estradiol valerate im on Day 0. The implant was removed on Day 9, with TAI 54 h later. Cows received 400 IU eCG or no further treatment on Day 9 and GnRH (100 μg gonadorelin) or no further treatment at TAI. Treatment with eCG increased the growth rate of the largest follicle from Days 9 to 11 (means ± SEM, 1.53 ± 0.1 vs. 0.48 ± 0.1 mm/d; P < 0.0001), its diameter on Day 11 (11.4 ± 0.6 vs. 9.3 ± 0.7 mm; P = 0.03), as well as ovulation rate (80.8% vs. 50.0%, P = 0.02), whereas GnRH improved the synchrony of ovulation (72.0 ± 1.1 vs. 71.1 ± 2.0 h). In Experiment 2 (n = 599 cows, 40 to 120 d postpartum), pregnancy rates differed (P = 0.004) among groups (27.6%, 40.1%, 47.7%, and 55.7% for Control, GnRH, eCG, and eCG + GnRH groups). Both eCG and GnRH improved pregnancy rates (51.7% vs. 33.8%, P = 0.002; and 48.0% vs 37.6%, P = 0.02, respectively), although their effects were not additive (no significant interaction). In conclusion, eCG at norgestomet implant removal increased the growth rate of the largest follicle (LF) from implant removal to TAI, the diameter of the LF at TAI, and rates of ovulation and pregnancy rates. Furthermore, GnRH at TAI improved the synchrony of ovulations and pregnancy rates in postpartum Nelore cows treated with a norgestomet-based TAI protocol.

Most of the world's bovine herd is found in tropical regions. Bos indicus predominates, due to their adaptation to the climate and management conditions. Anestrous is the main factor that negatively affects reproductive performance of animals bred in these regions of the globe. Several factors affect postpartum anestrous, including suckling and maternal-offspring bond, and pre- and postpartum nutritional status. The short duration of estrus and the tendency to show estrus during the night, greatly affect the efficiency of artificial insemination (AI) programs in B. indicus cattle managed in tropical areas. Several restricted suckling or weaning procedures (temporary or permanent), and hormonal treatments have been used to induce ovulation and cyclicity in postpartum cows. Most hormonal treatments are based on progesterone/progestogen (P4) releasing devices associated with estradiol benzoate (EB), or a combination of GnRH/PGF(2alpha)/GnRH (Ovsynch). Treatments with GnRH/PGF(2alpha)/GnRH has presented inconsistent results, probably due to the variable number of cows in anestrous. Treatments using P4 devices and EB have resulted in apparently more consistent results than Ovsynch programs in B. indicus cattle; however, pregnancy rates are low in herds presenting high anestrous rates and moderate to low body condition. The addition of an eCG treatment at the time of device removal, which increased plasma progesterone concentrations and pregnancy rates in anestrous postpartum suckled B. indicus cows, may be useful to improve reproductive performance of beef cattle in tropical climates.

This paper reports an accurate numerical analysis of some technological solutions for embedded airborne radars in the P- and X-bands applied to remote sensing. The propagation analyzes are based on Floquet and transient simulations by taken into account the influence of an entire fuselage from a commercial plane and the vegetation electromagnetic characteristics, similar to Amazon rainforest, in order to reproduce a realistic situation.

Os minérios de manganês provenientes da mina do Azul são importante matéria-prima na produção de ferro-ligas de manganês. Visando melhorias no beneficiamento e no processo de fabricação destas ligas, foi realizada a caracterização do produto Granulado da unidade do Azul-VALE/Manganês. Foi obtida uma amostra representativa desta mina e realizada análise granulométrica, onde se verificou a ocorrência de 80% das partículas abaixo de 22,6mm e 50% abaixo de 12,5mm. Considerou-se como granulado a fração menor que 37,5mm e maior que 6,3mm, que é a mais abundante neste minério e comumente destinada às usinas de ferro-ligas. A fração entre 37,5mm e 6,3mm foi amostrada e foram realizadas análises termogravimétrica, química dos elementos majoritários e identificadas as fases minerais presentes. A análise térmica (TG-DTA) identificou perda de massa em torno de 300oC, 500oC, 700oC, 900oC e 1000oC associadas à decomposição térmica de algumas fases minerais presentes. Os teores de Mn, Fe e SiO2 foram respectivamente, 47,68; 3,59; e 3,16%. O produto Granulado da unidade do Azul é composto majoritariamente pelos minerais de manganês criptomelana [KMn8O16] e pirolusita [MnO2]. Os constituintes minoritários são todorokita [(Na,Ca,K)2Mn6O12•3-4.5(H2O)], magnetita[Fe3O4] e gibbsita [Al(OH)3] (A pirolusita, a magnetita e a gibbsi-ta foram identificadas por microscopia óptica). The manganese ores from Azul mine are important raw materials for ferro alloys production. For improvements in the manganese ferro alloys production, Azul’s lump ore product was characterized. A repre-sentative sample from the mine has been obtained and their particle sizes were classified. The size distribu-tion showed that 80% of particles were below 22.6mm and 50% were below 12.5mm. The particles with sizes between 37.5mm and 6.3mm were named lump ore product. The fraction between 37.5mm and 6.3mm was submitted to chemical and mineralogical characterization. The TGA tests showed weight losses in 300oC, 500oC, 700oC, 900oC and 1000oC due, mainly, the high manganese oxides decompositions. The Mn, Fe and SiO2 contents were, respectively, 47.68%; 3.59% and 3.16%. Azul’s lump product has cryptomelane[KMn8O16] and pyrolusite[MnO2] as main mineralogical constituents. todorokite[(Na,Ca,K)2Mn6O12•3-4.5(H2O)], magnetite[Fe3O4] and gibbsite[Al(OH)3] appear as minor con-stituents (Pyrolusite, magnetite e gibbsite were identified by optical microscopy).

The objective of this study was to evaluate the effects of treatment with an intravaginal progesterone-releasing device (CIDR) and estradiol benzoate (EB) on follicular dynamics in Bos indicus (n=23), Bos taurus (n=25), and cross-bred (n=23) heifers. To assess the influence of reduced serum progesterone concentrations during 8 days of treatment with a progesterone-releasing device on follicular dynamics, half of the heifers received PGF at CIDR insertion (Day 0; 3 x 2 factorial design). Mean (+/-S.E.M.) serum progesterone concentrations during CIDR treatment varied (P

The objective was to evaluate the effects of 400 IU of eCG given on Days 5 or 8 of an estrus synchronization protocol with progesterone-releasing intravaginal devices (PRID) and estradiol benzoate (EB), in recipients for fixed-time embryo transfer. A secondary objective was to determine the effects of injectable progesterone (given concurrent with EB treatment). Three-hundred-and-four crossbred Bos taurus × Bos indicus beef heifers were randomly assigned to one of four treatment groups (2 × 2 factorial design). At unknown stages of the estrous cycle (Day 0), all heifers received a progesterone-releasing intravaginal device (PRID), plus 2 mg of EB i.m., with or without a concurrent treatment of 50 mg of progesterone i.m. Heifers were further subdivided to receive 0.15 mg of d -cloprostenol (PGF) i.m. and 400 IU of eCG i.m. on Days 5 or 8. In all heifers, intravaginal devices were removed on Day 8 and 1 mg of EB was given i.m. on Day 9 (Day 10 was arbitrarily considered the day of estrus). On Day 17, all heifers with >1 CL or a single CL with a diameter ≥18 mm (based on ultrasonographic examination), received an in vitro produced (IVP) embryo by non-surgical transfer. On Day 17, there was an effect of day of eCG administration on the number of CL (1.35±0.08 versus 1.13±0.04, for Day 5 versus Day 8, respectively; P =0.02) and (in a subset of 154 heifers) mean (±S.E.M.) plasma progesterone concentrations (2.41±0.26 versus 1.74±0.19 ng/mL; P =0.03). Although the proportion of recipients transferred/treated and pregnant/transferred did not differ among groups, the proportion of recipients pregnant/treated tended ( P =0.1) to be higher in heifers treated with eCG on Day 5 versus Day 8 (47.0% versus 40.7%, respectively). Progesterone treatment had no significant effect. In conclusion, treatment with eCG (and d -cloprostenol) on Day 5 significantly increased the number of CL and plasma progesterone concentrations and tended to increase pregnancy rates, although progesterone treatment had no significant effect.

Estradiol given during progestin-treatment promotes emergence of a new follicular wave in cattle. The interval from estradiol treatment to follicular wave emergence is dependent on the estradiol preparation, the dose, and possibly the animal category (cows or heifers). Therefore, this experiment aimed to compare the effects of either estradiol benzoate (EB) or estradiol valerate (EV) on the synchrony of ovarian follicular wave emergence in Bos indicus (Nelore) heifers and cows treated with a Norgestomet implant (Crestar�; Intervet, Boxmeer, The Netherlands; factorial 3 � 2 design). Lactating cows (n = 30; 70-90 days postpartum) and cycling heifers (n = 29) were homogeneously assigned, according to the presence of corpora lutea, to six experimental groups (G2EB, G2.5EV, and G5EV for each animal category). At random stages of the estrous cycle (Day 0), the females received an auricular implant and were assigned to receive 2 mg of EB (Farmavet, S�o Paulo, Brazil; 10 cows and 10 heifers; G2EB), 2.5 mg of EV plus 1.5 mg of Norgestomet (10 cows and 10 heifers; G2.5EV; half of a recommended dose), or 5 mg of EV plus 3 mg of Norgestomet (10 cows and 10 heifers; G5EV, full recommended dose) i.m. Transrectal ultrasonography was performed once daily from Day 0 to confirm the follicular dominance (new growing dominant follicle >8 mm in diameter). The day of wave emergence was retrospectively defined as the day when the dominant follicle was first detected at a diameter of 3 mm. Two-way analysis of variance was used to compare the effects of treatments (G2EB, G2.5EV, and G5EV), category (cows and heifers), and the treatments-by-category interaction on the interval from beginning of the treatment to wave emergence. The LSD was used to locate differences among groups and the Bartlett's test revealed heterogeneity of variance. Statistical analysis was conducted by SAS for Windows (SAS Institute, Inc., Cary, NC, USA). There was a significant effect of treatment and category (P < 0.001), but there were no treatments-by-category interactions (P > 0.05). A new follicular wave was induced in all animals after treatment with EB or EV. The heifers given G2EB (2.50 � 0.19a; 2 to 3x days) had a reduced (P < 0.01) and least variable interval (P < 0.05) than those given G2.5EV (4.20 � 0.27b; 3 to 6xy days) or G5EV (6.10 � 0.57c; 3 to 8y days). The cows given G5EV (4.00 � 0.52b; 2 to 6y days) had the longest (P = 0.05) and more variable interval (P < 0.001) than those given G2EB (2.50 � 0.22a; 2 to 4x days), but were similar to those given G2.5EV (3.10 � 0.41ab; 2 to 6xy days). The effect of EB was similar in heifers and cows (P > 0.05); however, the EV or 2.5EV promoted a longer emergence wave interval in the heifers than in the cows (P < 0.05). Analyzing the main effects, cows and heifers given G2EB (2.50 � 0.15a; 2 to 4x days) had a smaller and less variable interval than those given G2.5EV (3.65 � 0.27b; 2 to 6y) or G5EV (5.05 � 0.44c; 2 to 8z). In conclusion, the EV treatment, in both doses (5 or 2.5 mg), resulted in a delayed and more variable interval to emergence of a new follicular wave than 2 mg of EB in Bos indicus cows and heifers treated with a Norgestomet auricular implant. This work was supported by Intervet, Brazil.

The objective was to compare reproductive performance of breeding programs that used natural service (NS), AI after estrus detection (ED), and timed AI (TAI). In experiment 1, 597 suckled beef cows were randomly allocated to one of four groups. Cows in the TAI+NS group (N = 150) were bred by TAI at 11 days after the onset of the breeding season (BS). Bulls were placed with cows 10 days after TAI and remained together until the end of the 90-day BS. Cows in the TAI+ED+NS group (N = 148) received TAI, then AI based on ED for the next 45 days, and finally NS for the last 45 days of the BS. Cows in the ED+NS group (N = 147) received AI based on ED during the first 45 days of the BS, followed by NS for the last 45 days of the BS. Cows in the NS group (N = 149) were bred by NS for the entire 90-day BS. Cows in the ED+NS or NS groups had a decreased (P < 0.001) hazard of pregnancy compared with cows in the two groups bred by TAI at the onset of BS. Also, cows bred by TAI (TAI+NS = 92.7%; and TAI+ED+NS = 91.9%) had higher (P < 0.01) pregnancy rates at the end of the BS compared with cows not bred by TAI (ED+NS = 85.0%; NS = 83.2%). In experiment 2, 507 suckled beef cows were randomly assigned to one of two groups at the onset of a 90-day BS. The NS group (N = 255) received only NS during the entire BS, and the TAI+NS group (N = 252) received TAI at the onset of the BS, followed by NS until the end of BS. Cows in the TAI+NS group had 63% higher hazard of pregnancy (P < 0.001) compared with cows in the NS group, and reduced the median days to pregnancy by 44 (11 vs. 55 days). However, there was no difference (P = 0.31) in proportion of pregnant cows at the end of the BS (TAI+NS = 77.0% vs. NS = 71.0%). Therefore, incorporation of TAI programs early in the BS increased reproductive performance of suckled beef cows.