Institute of Electrical and Electronics Engineers (IEEE)CobosAbstract-The Steered Response Power -Phase Transform (SRP-PHAT) algorithm has been shown to be one of the most robust sound source localization approaches operating in noisy and reverberant environments. However, its practical implementation is usually based on a costly fine grid-search procedure, making the computational cost of the method a real issue. In this paper, we introduce an effective strategy that extends the conventional SRP-PHAT functional with the aim of considering the volume surrounding the discrete locations of the spatial grid. As a result, the modified functional performs a full exploration of the sampled space rather than computing the SRP at discrete spatial positions, increasing its robustness and allowing for a coarser spatial grid. To this end, the Generalized Cross-Correlation (GCC) function corresponding to each microphone pair must be properly accumulated according to the defined microphone setup. Experiments carried out under different acoustic conditions confirm the validity of the proposed approach.Index Terms-sound source localization, SRP-PHAT, microphone array.

The effects of once (1X) vs. twice (2X) daily milking throughout lactation on milk yield, milk composition, somatic cell count (SCC), and udder health were studied in 32 Murciano-Granadina dairy goats. Goats were assigned at wk 2 of lactation to two treatment groups; once daily milking at 0900 (1X, n = 17), or twice daily milking at 0900 and 1700 (2X, n = 15). Milk yield was recorded weekly until wk 28, and milk composition and SCC were evaluated for each individual udder half at each milking at wk 2 and 4 of lactation and then, monthly until the end of the experiment. Once daily milking resulted in an 18% reduction in the yield of 4% fat-corrected milk compared to twice daily milking (1.61 vs. 1.95 L/d, respectively). This reduction was more marked from wk 2 to 12 than in mid and late lactation. Response to milking frequency also varied according to parity number where goats of less than four parities suffered more milk yield losses during 1X than older goats. Milk of 1X goats contained higher percentages of total solids (13.6 vs. 12.9%), fat (5.10 vs. 4.62%) and casein (2.57 vs. 2.35%) than milk of 2X goats, but milk protein percentage did not differ between treatments (3.28 vs. 3.20%). Yields of total solids, fat, protein and casein tended to be higher for 2X than 1X. Milk SCC did not differ between treatments. We conclude that application of once daily milking in Murciano-Granadina dairy goats moderately reduced milk yield without negative effects on milk composition and udder health. Losses in milk yield would be reduced if 1X is practiced during mid- or late lactation and in older goats. An increase in labor productivity and a higher farmer's standard of living is also expected.

The impact of a large rhizosphere alkalisation on copper (Cu) bioavailability to durum wheat (Triticum turgidum durum L.) initially exposed to a broad range of bulk soil pH (4.8-7.5) was studied. Plants were exposed to a Cu-contaminated soil treated with eight levels of lime (Ca(OH) 2 ) and supplied with NO 3 − or NH 4 + -NO 3 − . Nitrate-fed plants strongly increased their rhizosphere pH to about 6.9-7.6, whatever the initial pH. NH 4 + -NO 3 − -fed plants slightly acidified their rhizosphere down to 3.9. Free Cu 2+ concentration in the rhizosphere was 3 orders of magnitude larger for NH 4 + -NO 3 − than NO 3 − fed plants. Consequently, Cu bioavailability was 2.4-to 4.2-fold larger for NH 4 + −NO 3 − -fed plants which demonstrates the importance of rhizosphere alkalisation to restrict metal bioavailability in acidic soils. Copper bioavailability of NO 3 − -fed plants initially exposed to a broad range of bulk soil pH was insensitive to bulk soil pH, as rhizosphere pH was ultimately neutral in any case.

Source localization using the steered response power (SRP) usually requires a costly grid-search procedure. To address this issue, a modified SRP algorithm was recently introduced, providing improved robustness when using coarser spatial grids. In this letter, an iterative method based on the modified SRP is presented. A coarse spatial grid is initially evaluated with the modified SRP, selecting the point with the highest accumulated value. Then, its corresponding volume is iteratively decomposed by using a finer spatial grid. Experiments have shown that this method provides almost the same accuracy as the fine-grid search with a substantial reduction of functional evaluations.

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In this work on machine milking of ewes, pulsation rates of 120 and 180 cycles per min were compared, both with a pulsation ratio of 50:50 and a vacuum level of 36 kPa, comparing intramammary infection (IMI), somatic cell count (SCC) and teat end thickness changes. To this end, two groups of 20 Manchega ewes were used in a crossover experimental design with two experimental periods of 24 d for each. Bacterial exposure of all teats was increased by dipping them in a suspension of Staphylococcus simulans at four consecutive milkings of each period. Pulsation rate of 180 cycles per min, compared with 120 cycles per min, had no negative effect upon new IMI (11 and 16% of ewes infected, respectively) and SCC. No teat end lesions were observed in those animals milked with the two pulsations assayed. Also, teat thickness changes (-0.38 and -0.36 mm at 120 and 180 cycles per min, respectively) were not affected significantly. Finally, in absence of IMI, the two pulsation rates assayed did not affect the SCC.

Two repeated experiments were carried out in 2 different years to study the effect of estrus on somatic cell count (SCC) in dairy goats. In the first year, 36 Murciano-Granadina goats were used [12 primiparous and 24 multiparous; 22 healthy and 14 with an intramammary infection (IMI)] and, after a 6-d pre-experimental period, were divided into 2 groups according to lactation number, udder health status, SCC, and milk production. One group was kept as a control, whereas the other received an estrus synchronization hormonal treatment lasting 11d. At 24, 48, and 72h after cessation of the hormone treatment, goats were placed in contact with a buck to confirm that they were in estrus. For 32 consecutive days (6 pre-experimental, 11 in hormone treatment, and 15 post-treatment) the SCC per gland and udder were monitored in all animals. In the second year, we repeated the same experimental design using a total of 38 Murciano-Granadina breed goats (12 primiparous and 26 multiparous; 26 healthy and 12 with IMI). Throughout this experiment, milk yield and composition were also recorded daily for each goat. Upon termination of the hormonal treatment, the SCC in udder milk increased significantly in the treatment group compared with the control group over 3 consecutive days. This increase was observed for year (1 and 2), parity (primiparous and multiparous), and udder health status (healthy and IMI). The log10 SCC (cells/mL) increased from 5.5±0.09 before estrus to 6.04±0.09 during treatment; therefore, the geometric mean of the SCC increased 3.5 times during treatment. The maximum values obtained in healthy glands of primiparous goats (geometric mean=0.37 million cells/mL) were lower than in healthy glands (1.1 million cells/mL) or infected glands (1.7 million cells/mL) of multiparous goats. The increase in SCC observed during estrus (200% increase in geometric means) could not be explained by the changes in milk production, which only fell by 13%. During estrus, the percentage of protein and dry matter in the milk also increased significantly. We concluded that it is necessary to consider the presence of estrus to correctly interpret milk SCC, as an indirect method for detecting IMI or as a commercial milk quality parameter.

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