Cent Zinc Research Articles

Effect of nutrient levels and schedule of nutrient application on the grain quality of upland rice intercropped in coconut

Field experiment was conducted at Coconut Research Balaramapuram, during Kharif 2017 to study the effect of nutrient levels and schedule of application on the quality parameters of upland rice intercropped in coconut. The experiment was conducted in randomized block design (RBD) with four different nutrient levels and four different schedules of nutrient application. Quality parameters like crude protein and starch content were significantly influenced by nutrient levels. The crude protein content was found to increase with increase in N level, however starch content was found to increase up to 70 kg N and 35 kg K ha-1 and after that a decline in trend was observed. The highest crude protein content (8.38 per cent) was recorded with highest nutrient level, NPK @ 120:30:60 kg ha-1. However, lower nutrient level, NPK @ 70:30:35 kg ha-1 recorded higher starch content (85.03 per cent). Among the schedule of nutrient application, N applied in three equal splits (15 days after sowing (DAS), active tillering and panicle initiation stage), P as basal and K in two equal splits (15 DAS and panicle initiation stage) along with foliar application of 0.2 per cent zinc sulphate and 0.04 per cent sodium borate at 45 DAS recorded the highest crude protein (7.50 per cent) and starch content (84.17 per cent). The study clearly indicated that the increased level of N and K increased the protein content due to the active role of N and K in protein synthesis. However, high rate of N application decreased the starch content. In addition to the application of NPK, foliar nutrition of zinc sulphate and sodium borate at 45 DAS considerably improved the quality of grain by increasing the starch and protein content.

Effect of nutrient levels and nutrient schedules on physiological parameters and grain yield of upland rice intercropped in coconut garden

The experiment was conducted at Coconut Research Station, Balaramapuram with an objective to study the effect of nutrient levels and nutrient schedules on physiological parameters and grain yield of upland rice (MO 21- Prathyasa rice variety) intercropped in coconut. Field experiment was conducted in factorial randomized block design with nutrient levels as first factor and nutrient schedules as second factor in three replications. Nutrient levels had significant effect on the physiological parameters. Among the nutrient levels rested, NPK applied @ 120:30:60 recorded higher total chlorophyll (2.803 mg g-1) and chlorophyll b content (1.508 mg g-1), crop growth rate (CGR) (11.23 g m-2 day-1) and relative growth rate (RGR) (0.056 g g-1 day-1) as compared to lower nutrient level tested, NPK @ 60:30:30 kg ha-1. Nutrient schedules also had significant effect (P=0.05) on the physiological parameters viz., total chlorophyll, chlorophyll a, chlorophyll b, CGR and RGR and the treatment receiving 0.2 per cent zinc sulphate and 0.04 per cent sodium borate spray at 45 DAS recorded higher chlorophyll content, RGR and CGR. Though the higher nutrient level, NPK @ 120:30:45 kg ha-1 recorded higher values for physiological parameters, it recorded the lowest grain yield. Application of NPK @ 90:30:45 kg ha-1 recorded the highest grain yield and it was followed by NPK applied @ 70:30:35 kg ha-1. Among the nutrient schedules, N applied as three equal splits, P as basal and K in two equal splits along with foliar spray of zinc sulphate 0.2 per cent and sodium borate 0.04 per cent at 45 DAS recorded the highest grain yield (3.25 t ha-1). The study clearly revealed that excessive vegetative growth is not a desirable parameter for higher grain yield.

Growth, yield and fruit quality of Kinnow mandarin as affected through foliar application of zinc and boron

The investigation was undertaken with a view to determine the growth, yield and fruit quality of Kinnowmandarin as affected through foliar application of zinc and boron. The results revealed that combined applicationof 0.2 per cent boric acid + 0.5 per cent zinc sulphate at fruit set and peach size stage of fruit through foliarspray exerted significant influence on plant height, tree spread and shoot length. The maximum fruit retention (71.77%), number of fruits plant−1(486.24), fruit weight (163.23 g), fruit volume (194.79 cc), fruit diameter (7.16 cm), yield plant−1 (79.32 kg) and yield ha−1 (31.73 t) were recorded in treatment T9 (0.2 per cent boric acid + 0.5per cent zinc). The same treatment had markedly influenced the quality of Kinnow fruit and the maximum TSS (12.18 oBrix), TSS/acid ratio (16.66), reducing sugars (3.87%), total sugar (7.22%), ascorbic acid (25.16mg/100 g)and juice content (41.43%) were recoreded in this traetement (T9). The lowest acidity (0.73%) and rind thickness (2.79 mm) were also recorded in treatment T9 (0.2 per cent boric acid + 0.5 per cent zinc). This treatment alsoincreased the zinc (100.08 ppm) and boron (80.81 ppm) level of kinnow mandarin leaves.

Genotypic Divergence in Per Cent Zinc Derived from Variable Sources and on Zinc Uptake in Rice [Oryza sativa (L.)] as Established by Radiotracer Techniques

A pot culture experiment was conducted at Tamil Nadu Agricultural University, Coimbatore to establish the genotypic divergence in per cent zinc (Zn) derived from fertilizer (% Zndff) or from soil (% Zndfs) and on zinc uptake of two rice genotypes Zn -efficient Norungan and Zn –inefficient PMK 3. To assess the partitioning of Zn in the shoot and root of the genotypes, radiotracer technique was employed, in which graded levels of Zn (0.0, 12.5, 25.0, 37.5 and 50.0 kg ha-1 of ZnSO4) as 65Zn labeled ZnSO4 were applied. Per cent Zndff showed an increase by 50 % for Zn-inefficient PMK 3 than that for Norungan while reverse was the trend for % Zndfs implying the fact that Zn inefficient genotypes have the ability to use only readily available sources of Zn. Zinc uptake from fertilizer increased with increasing dose of applied zinc for PMK 3 while in Norungan it showed a peak at 25 kg ha-1 of ZnSO4 and thereafter it declined. Irrespective of the sources of zinc, root zinc accumulation was higher in PMK 3 than that in Norungan. The Zn-efficient genotype Norungan had better translocation of Zn from root to shoot than PMK 3.

Contribution of liquid fertilizers to improve productivity of late sown wheat in western plain zone of Uttar Pradesh

The field experiments were conducted in Muzaffarnagar districtof Uttar Pradesh in winter of 2011-12 and 2012-13 to estimate the effect of liquid applied nutrients on the yield of late sown wheat at ten farmer’s fields. The wheat variety PBW-373 was grown in both the year experiments. Soil of the experimental site was physico-chemically analyzed before sowing of experiments. Nutrient solution were prepared for liquid application as one per cent sulphur solution prepared from 80 per cent W.P. sulphur, 1 per cent iron solution prepared from 19 per cent ferrous sulphate, 0.5 per cent zinc solution prepared from 21 per cent zinc sulphate and 0.5 per cent manganese solution prepared from 30.5 per cent manganese sulphate commercially available from the market. These solutions were sprayed on standing crop at tillering and boot stage (30 and 60 days after sowing). All the liquid applications were in addition of farmer used fertilizer. Farmers in Muzaffarnagar district generally using NPK 145:80:40, as 5 bag NPK (12:32:16) and 5 bag of urea (46 % N) in one hectare of wheat production.The maximum grain yield (41.4 q/ ha) was recorded from zinc application and lowest (39.0 q/ ha) from control treatment. Grain yield 40.08 q/ ha had been obtained from sulphur application and 39.6q/ ha from iron 40.3q/ ha application and 39.6q/ ha from manganese treatment in Rabi 2011-12. It was also noted that zinc application was significantly increased yield over control.The maximum yield (39.6 q/ ha) was observed from zinc application followed by sulphur application (39.2 q/ ha) which was significant over control treatment in Rabi 2012-13. Lowest yield (38.0 q/ ha) was found from control treatment, 38.5 q/ ha from iron application and 37.8 from manganese treatment. Straw yield 50.1 q/ ha recorded from zinc application, followed by sulphur (49.6 q/ ha), iron (48.6 q/ ha) and 48.1 q/ ha from manganese treatment. It was observed that number of tillers, grain and straw yield were significantly increased over control fromliquid application zinc both the year of experiments.

Effect of foliar spray of urea and zinc on growth and flowering attributes of guava (Psidium guajava) cv. BHAVNAGAR RED

Study was conducted in experimental farm of Junagadh Agricultural University, Gujarat India to find out the effect of foliar application of 1.0 per cent, 1.5 per cent or 2.0 per cent urea and zinc sulfate with concentration of 0.2, 04 and 0.6 per cent on guava crop, respectively, just before blooming significantly improved shoot growth, leaf number, area and weight. The best results were obtained with treatments of 1.0 and 1.5 per cent foliar spray of urea. In case of flowering, fruit set and fruit retention was better in treated plants with fertilizer. The size of fruits and yield per tree increased with increasing urea concentration and the significant variation in number of flowers per shoot was observed while non significant effect was observed under interaction effect of urea and zinc. The highest fruit weight and maximum fruit girth was registered with 0.6 per cent zinc. Thus, it is proved that 1.5 per cent urea solution and 0.6 per cent zinc sulphate were effective for the augmentation of growth and flowering attributes of guava.

Tribological characteristics at running‐in of repaired tractor engines using friction modifiers

PurposeThe purpose of this paper is to determine and compare the tribological characteristics (weight wear and friction moment) of a friction couple C45/C330 at running‐in with motor oil SAE 30 and different friction modifiers of copper oleate and zinc oleate.Design/methodology/approachFriction couples are tested using the model “roller‐sector” and they are lubricated with oil SAE 30 and two other samples of SAE 30 containing 0.6 per cent copper oleate and 0.6 per cent zinc oleate, respectively. Graphic dependencies are drawn for the weight wear of the sectors, rollers and couples; as well as for the running‐in moment, the friction moments at the end of the loading and at the end of the test.FindingsThe weight wear, running‐in moment and friction moments are evaluated for friction with SAE 30 as reference and oils containing copper oleate and zinc oleate as friction modifiers. The best performing material is the oil with zinc oleate.Originality/valueFrom a practical point of view this paper offers a new idea about a friction modifier – zinc oleate. Data for tribological characteristics and suitable concentration in the oil composition are given in the paper.

Creating a New Staple: Capital, Technology, and Monopoly in British Columbia’s Resource Sector, 1901-1925

This paper examines the mining industry of British Columbia, the province's leading staple during the period when the region was brought within the network of world trade. Specifically, it describes the emergence of zinc production as the most profitable sector of the industry, from the early 1900s through to the mid-1920s. A good deal of importance was attached to discovering some means of treating zinc ore in the early 1900s. Increasing amounts of zinc were being found in the silver-lead ore of eastern British Columbia. Zinc was seen as a contaminant, and smelters penalised mine-owners who shipped ore that was over 10 per cent zinc. The presence of zinc rendered relatively valuable ore (in terms of its silver and lead content) uneconomical. Concern over “the zinc problem” was such that, by 1905, the federal government, responding to the lobbying efforts of mine-owners, appointed a commission “to Investigate the Zinc Resources of British Columbia and the Conditions Affecting Their Exploitation”. During the next twenty years, mining companies in the Kootenays explored a number of different ways to overcome zinc's unfortunate impact upon the mining industry. These efforts to discover an adequate means to treat zinc ore illustrate the way in which technology and capital became the key ingredients of a distinctively new mining industry. The paper argues that the emergence of zinc mining reflected a fundamental restructuring of the industry, as the focus shifted from the discovery and exploitation of bonanza deposits of gold and silver to the less spectacular production of copper, lead, and zinc. Technology, economies of scale, and substantial capital investment were the hallmarks of the new industry. Not only was the industry profoundly altered — experiencing what other scholars have described as the second industrial revolution — but new vertically integrated companies displaced the traditional mining company. The paper describes the clearest example of this trend, outlining the early career of the Consolidated Mining and Smelting Company of Canada [Cominco], a subsidiary of the Canadian Pacific Railway. Cominco was able to put in place the necessary technology to tap its enormous lead-zinc deposit at Kimberley, and successfully treat zinc at its Trail refinery. Within two decades, and largely as a result of its ability to treat zinc, Cominco became the most profitable mining company ever to operate in British Columbia. The conclusion suggests some consequences of Cominco's ascendancy.

Vitamin E and mineral fortification in fresh‐cut apples (Fuji) using vacuum impregnation

PurposeThis study aims to evaluate the use of vacuum impregnation (VI) for developing vitamin E fortified fresh‐cut apples (Fuji).Design/methodology/approachA 20 per cent high fructose corn syrup (HFCS) or edible coating materials of 1 per cent hydroxypropyl methylcellulose (HPMC) and 1 per cent calcium caseinate (CC) were used to make VI solutions, and 0.4 per cent α‐tocopherol acetate, 7.5 per cent gluconal cal\tf="Pi3" \char"31 (GC) and 0.04 per cent zinc lactate (ZL) were incorporated into the VI solutions. Vitamin E content, color, and selected physicochemical properties of fortified fresh‐cut apples were analyzed.FindingsResults showed that VI treatment with 20 per cent HFCS solution containing 0.4 per cent α‐tocopherol acetate increased vitamin E content up to 21.8 mg in 100 g of fresh‐cut apples, while 12.0 mg and 20.2 mg vitamin E were achieved when using 1 per cent HPMC or 1 per cent CC as VI solutions, respectively. Calcium and zinc content were also increased to 146.6 mg and 1.7 mg in 100 g of apples, respectively, when adding 7.5 per cent GC and 0.04 per cent ZL along with the vitamin E into the VI solutions. Use of HFCS, HPMC and CC as VI solutions resulted in different effects on the physiochemical properties of fresh‐cut apples. While HFCS is promising for vitamin E fortification and retention of natural apple color, HPMC and CC can be used to achieve similar vitamin E fortification with the least impact on the soluble solids and moisture contents of apples.Originality/valueThe study demonstrates that there is great potential for developing high quality, vitamin E and minerals fortified fresh‐cut apples using vacuum impregnation technology, thus further enhancing the health benefit of the apples.

Britain's First Brass

Stamps on the blade of a sword from the Thames, originally considered to be Anglo-Saxon, now place the sword stylistically in the La Tène II period (late third to early second century BC). X-ray fluorescence tests have shown that the gold-coloured foil covering the stamps consists of 80 per cent copper and 20 per cent zinc, this being the formula for brass. The sword therefore represents the earliest known use of brass in Britain.

The significance of the source of zinc and its anti-VSC effect

The anti-VSC (volatile sulphur compounds) effect of zinc is known to be associated with free zinc ions. To examine whether zinc salts with low stability constants were more suitable as sources of zinc in zinc lozenges than zinc salts with high stability constants. The former provide free zinc ions upon dissolution in water, whereas the latter provide few such ions. Identical lozenges were produced which contained either zinc acetate, zinc gluconate (low stability constants), zinc citrate or amino-acid chelated zinc (extremely high stability constants). All the lozenges contained 0.1 per cent of zinc. A test panel of 10 volunteers used the different lozenges randomly. VSC were measured by GC. The lozenge with the highest stability constant was as effective as those with very low stability constants. The anti-VSC effect was thus not related to this constant. These findings may be explained by the possibility that alternative ligands with stronger affinity for zinc than the original ligands in the lozenges may be present in the oral cavity. An in vitro experiment indicated that the sulphide ion (S2-) may be such a ligand.

Tokaimura accident. Neutron dose estimates from 5-yen coins.

After a criticality accident at a nuclear-fuel processing facility in Tokaimura, Japan, at 10:35 Japanese standard time on 30 September 1999, neutron emission continued until early the next morning. To estimate the neutron dose to the surrounding population, we collected 5-yen coins (37 weight per cent zinc) from places likely to have been exposed to radiation as a result of the accident and determined the amount of 65Zn generated in them in the nuclear reaction 64Zn+n→65Zn by spectrometrically measuring the photons emitted by 65Zn. Our results indicate that people evacuated to 350 m outside the irradiated area still received a significant neutron dose.

The Citronen Fjord massive sulphide deposit, Peary Land, North Greenland: discovery, stratigraphy, mineralization and structural setting

The Citronen Fjord massive sulphide deposit in the Lower Palaeozoic of North Greenland is the world's most northerly base metal mineralization. Since discovery in 1993, it has been intensively investigated by geological and geophysical surveys, and by drilling. The deposit is generally flat lying with a thickness up to 50 m; it extends from outcrop level to depths of 300 m.
 Three main stratiform sulphide sheets occur within a 200 m thick stratigraphic sequence; these are composed of massive and bedded pyrite with variable amounts of sphalerite and minor galena. The proven mineralization is continuous over a strike length of at least 3 km with a maximum width of 500 m; an additional 5 km of mineralization along the same trend is suggested by geological mapping and gravity surveys. The total tonnage of sulphides is estimated to exceed 350 million tons. The overall base metal resource is estimated at 20 million tons of 7 per cent zinc, with a higher grade core of 7 million tons containing 9 per cent zinc and 1 per cent lead.
 The Citronen Fjord deposit is located at the eastern end of the Palaeozoic Franklinian Basin that extends through the Arctic Islands of Canada and across northern Greenland. Its discovery is an example of a successful exploration strategy based on regional evaluation, sparse but telltale surface mineralization observations and low-cost logistics: a skidoo-sledge expedition. The stratiform mineralization is hosted in the dark argillaceous rocks of the Amundsen Land Group of latest Ordovician to Early Silurian age that comprises a starved basin sequence of cherts and shales with siltstones and mudstones, punctuated by carbonate debris flow conglomerates derived from the nearby southern carbonate shelf. The Lower Palaeozoic strata at Citronen Fjord are part of the southern margin of the North Greenland Fold Belt characterized by southerly-facing folds and thrust faults.
 A new geological map of the Citronen Fjord area is presented featuring Cambrian, Ordovician and Silurian strata, with two north-south cross-sections illustrating the main structure. Twelve informally-named lithostratigraphic units are recognized and comments given on correlation to the regional stratigraphy. Tectonic contacts separate Lower Cambrian strata from the Ordovician-Silurian part of the succession. It is concluded that the Citronen Fjord stratigraphy could be of local development in a sub-basin controlled by syn-genetic faults.
 The lead-zinc deposit is interpreted to be of sedimentary-exhalative origin formed by the precipitation of sulphides from metal-bearing fluids introduced onto the sea-floor through underlying fractures. The significant components of this deposition model include the existence of a tensional tectonic regime, deep-seated fractures and a restricted sub-basin morphology. Massive to dendritic-textured pyrite is interpreted to represent vent-facies deposition while the bedded sulphides are taken to be the corresponding distal facies. The precise tectonic control of the fractures is debatable, as is the role of the so-called Navarana Fjord Escarpment - a palaeo-topographic feature marking the junction between shelf and trough that is assumed to lie immediately to the south of the Citronen Fjord.

The Citronen Fjord massive sulphide deposit, Peary Land, North Greenland: discovery, stratigraphy, mineralization and structural setting

The Citronen Fjord massive sulphide deposit in the Lower Palaeozoic of North Greenland is the world's most northerly base metal mineralization. Since discovery in 1993, it has been intensively investigated by geological and geophysical surveys, and by drilling. The deposit is generally flat lying with a thickness up to 50 m; it extends from outcrop level to depths of 300 m.
 Three main stratiform sulphide sheets occur within a 200 m thick stratigraphic sequence; these are composed of massive and bedded pyrite with variable amounts of sphalerite and minor galena. The proven mineralization is continuous over a strike length of at least 3 km with a maximum width of 500 m; an additional 5 km of mineralization along the same trend is suggested by geological mapping and gravity surveys. The total tonnage of sulphides is estimated to exceed 350 million tons. The overall base metal resource is estimated at 20 million tons of 7 per cent zinc, with a higher grade core of 7 million tons containing 9 per cent zinc and 1 per cent lead.
 The Citronen Fjord deposit is located at the eastern end of the Palaeozoic Franklinian Basin that extends through the Arctic Islands of Canada and across northern Greenland. Its discovery is an example of a successful exploration strategy based on regional evaluation, sparse but telltale surface mineralization observations and low-cost logistics: a skidoo-sledge expedition. The stratiform mineralization is hosted in the dark argillaceous rocks of the Amundsen Land Group of latest Ordovician to Early Silurian age that comprises a starved basin sequence of cherts and shales with siltstones and mudstones, punctuated by carbonate debris flow conglomerates derived from the nearby southern carbonate shelf. The Lower Palaeozoic strata at Citronen Fjord are part of the southern margin of the North Greenland Fold Belt characterized by southerly-facing folds and thrust faults.
 A new geological map of the Citronen Fjord area is presented featuring Cambrian, Ordovician and Silurian strata, with two north-south cross-sections illustrating the main structure. Twelve informally-named lithostratigraphic units are recognized and comments given on correlation to the regional stratigraphy. Tectonic contacts separate Lower Cambrian strata from the Ordovician-Silurian part of the succession. It is concluded that the Citronen Fjord stratigraphy could be of local development in a sub-basin controlled by syn-genetic faults.
 The lead-zinc deposit is interpreted to be of sedimentary-exhalative origin formed by the precipitation of sulphides from metal-bearing fluids introduced onto the sea-floor through underlying fractures. The significant components of this deposition model include the existence of a tensional tectonic regime, deep-seated fractures and a restricted sub-basin morphology. Massive to dendritic-textured pyrite is interpreted to represent vent-facies deposition while the bedded sulphides are taken to be the corresponding distal facies. The precise tectonic control of the fractures is debatable, as is the role of the so-called Navarana Fjord Escarpment - a palaeo-topographic feature marking the junction between shelf and trough that is assumed to lie immediately to the south of the Citronen Fjord.

Chemical abundances in the young galaxy at z=2.309 towards PHL 957

We present high-resolution Utrecht Echelle Spectrograph spectra of the quasar PHL 957, obtained in order to study the foreground damped Lyα (DLA) galaxy at z=2.309. Measurements of absorption lines lead to accurate abundance determinations of Fe, S and N which complement measurements of Zn, Cr and Ni already available for this system. We find [Fe/H]=−2.0±0.1, [S/H]=−1.54±0.06 and [N/H]=−2.76±0.07. The ratio [Fe/Zn]=−0.44 provides evidence that ≈74 per cent of iron and ≈28 per cent of zinc are locked into dust grains with a dust-to-gas ratio of ≈3 per cent of the Galactic one. The total iron content in both gas and dust in the DLA system is [Fe/H]=−1.4. This confirms a rather low metallicity in the galaxy, which is in the early stages of its chemical evolution. The detection of S ii allows us to measure the S ii/Zn ii ratio, which is a unique diagnostic tool for tracing back its chemical history, since it is not affected by the presence of dust. Surprisingly, the resulting relative abundance is [S/Zn]=0.0±0.1, at variance with the overabundance found in the Galactic halo stars with similar metallicity. We emphasize that the [S/Zn] ratio is solar in all the three DLA absorbers with extant data. Upper limits are also found for Mn, Mg, O and P and, once the dust depletion is accounted for, we obtain [Mg/Fe]c<+0.2, [O/Fe]c<+0.4, [Mn/Fe]c<+0.0 and [P/Fe]c<−0.7. The [α/Fe] values do not support Galactic halo-like abundances, implying that the chemical evolution of this young galaxy is not reproducing the evolution of our own Galaxy.

RELATIVE UTILISATION OF DIFFERENT ZINC CARRIERS IN WETLAND RICE (Oryza sativa)

The utilisation of fertiliser zinc by rice crop was studied using few 65 Zn-labelled zinc carriers in a greenhouse experiment on an Udic Haplustalf and an Entic Chromustert. With respect to the yield of grain and straw, ZnSO4 was found to be the best among the zinc carriers tried. Its effect was more pronounced when applied along with ammonium polyphosphate, However, the per cent zinc utilisation followed the order:-Zincated urea &gt; ZnsO4&gt; ZnSO4+APP &gt; Zincated DAP.

Urinary zinc excretion in a patient with burns: a caveat when using bladder catheters in urine zinc studies

The results of a longitudinal study on plasma and urine zinc concentrations in a patient with 68 per cent burns are described. Special attention was paid to possible zinc contamination due to the use of bladder catheters for urine sampling. The course of the plasma and urine zinc concentrations during the first 50 days in hospital was comparable to those reported in the literature. It was shown that surgery was associated with a pronounced rise in urine zinc level, while catheter replacement caused no significant increase in urinary zinc content in this particular patient. However, measurements of zinc content of and zinc release from three types of bladder catheters showed that the two types of latex-based catheters contained about 0.25 per cent zinc, versus 0.01 per cent in the siliconelastomer equivalent. During an 8 h perfusion latex catheters released about 1.2 μmol zinc (2.5 μmol/l). Possible errors in urine zinc determinations due to zinc contamination from catheters are calculated. Recommendations are made for minimizing these errors.

In vitro penetration and absorption of chemicals into the ovine hoof

Techniques are described for testing the ability of chemicals to penetrate through ovine hoof horn. Most chemicals tested had penetration rates of less than 0.1 mm per hour and formalin, a chemical widely used for treatment of foot rot, penetrated very poorly (less than 0.02 mm per hour). Chloramphenicol in ethanol solution gave the highest penetration rate (0.21 to 2.38 mm per hour) and other penetrative chemicals were zinc sulphate (0.06 to 0.58 mm per hour), copper sulphate (less than 0.05 to 0.38 mm per hour) and sodium azide (less than 0.05 to 0.24 mm per hour) in aqueous solution. Inclusion of sodium lauryl sulphate in treatments enhanced the penetration rates of zinc and azide approximately sixfold. Ethanol and nickel ammonium hydroxide also improved the penetration of zinc and azide, particularly through the hard horn from the abaxial wall of the claw. Absorption of zinc from solutions containing 10 per cent zinc sulphate gave hoof tissue concentrations of zinc from 0.22 to 0.88 mg zinc ions per g tissue (10 to 20 times that found in normal hoof samples) and most of this zinc was retained after the horn was washed continuously in running water for 24 hours.

Involvement of various senses in responses to individual housing in laboratory albino mice: 1.The olfactory sense

Abstract ‘Isolation’ of male mice is much used to induce aggressiveness but, as practised in most laboratories, does not preclude communication between neighbouring conspecifics. This study examines the influence of olfaction on individual housing-induced social conflict between male laboratory mice. Attempts were made both to eliminate and to intensify the exposure to presumably socially meaningful odours. First, the effects of acute and chronic anosmia induced by application of four per cent zinc sulphate solution to the nostrils were determined in mice from a range of ages and social experiences. Secondly, the influences on the subsequent aggressiveness of the individually-housed male mice were estimated after introducing into their cages odoriferous bedding from groups of male and of female conspecifics. Both acute and chronic anosmia depressed the attacks directed towards ‘standard opponents’; indeed the chronic treatment virtually abolished this behaviour. Adding odoriferous bedding from the cages o...

Equipment

Pegasus Finishing Ltd, trade finishers of Harlow, are now using an Airmix 25:150 pump, together with two Airmix spray guns, from Kremlin Spray Painting Equipment Ltd, 839 Yeovil Rd, Slough SL1 4JA, for the spraying of a 70 per cent zinc rich anti‐corrosion primer. The parts being sprayed will form the insides of box sections for the car industry. The outsides, which will eventually be coated by Pegasus Finishing's motor industry customers, are spray painted—again using Kremlin Airmix equipment— with an oil‐based temporary protective coating.