465 research outputs found

    The influence of heading back on bud performance of one year-old apple shoots

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    Pruning is one of the oldest and most universally practiced orchard operations. (1) The fundamental objectives of pruning are to improve the quality and quantity of fruit and to lower the cost of production. There is no horticultural practice on which there is greater diversity of opinion or application of procedure. (7) The average grower, when asked why he does or does not prune, generally will reply that it is good or not good for the tree. (?) Some of the specific objectives assigned to pruning are (1) to open the tree for more fruit color, (2) train to a desired form, (3) remove dead and diseased parts, (4) remove water sprouts and cross-branches and (5) to thin fruit. (7) Pruning may vary in three respects; (1) the amount of wood removed, or severity, (2) the kind or position and (3) the season. There are two methods of pruning; thinning out and heading back. Thinning out is a method that removes whole shoots or branches. Heading back removes a portion of a shoot. The lateral buds of most species of plants are formed in the axil of each leaf. They seldom grow immediately, but tend to remain dormant during the season in which they are formed. Failure of the newly formed lateral buds to grow immediately is commonly attributed to apical dominance. If the terminal bud is removed, one or more of the lateral bids may begin to grow. Inhibition of the lateral buds by the terminal bud seems to be a polar phenomenon influenced by gravity. It has been shown, using indoleacetic acid on the cut surface following removal of the terminal bud, that the lateral buds remain quiescent as if the terminal bud were present. This suggests that an auxin might be produced by the terminal bud or in the region of the terminal bud. It is interesting to speculate on the reasons why the terminal bud, which is considered as the site of auxin production, continues to grow actively when buds behind it are inhibited. Apple flowers are usually borne terminally on short shoots known as spurs. Occasionally flowers are borne terminally on shoots. Some varieties produce flowers rather commonly in this fashion. Individual spurs seldom bear annually, although the spurs of some varieties are more likely to do so than others. Heavy annual production depends on the formation of numerous new spurs and the maintenance of old spurs in a vigorous condition. Spurs are usually produced from lateral buds of the preceding season\u27s growth, rarely on old wood from either latent or adventitious buds. Previous studies have been done to determine the effect of severity of pruning on trees as a whole, but not on the effect of bud performance on shoots. The objectives of this investigation were to determine the effect of heading back one-year-old wood on the establishment of the spur system, the production of new shoots, and the forcing of buds which are expected to remain dormant or latent

    An Investigation of Some of the Environmental and Edaphic Factors Effecting the Detoxification and Subsequent Degradation of an Herbicide, Butachlor

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    The influence of specific edaphic environmental factors on the detoxication and subsequent degradation of N-Butoxymethyl-2-chloro-2\u27, 6\u27 diethylacetanilide (butachlor) was evaluated under greenhouse and growth chamber conditions. Detoxication of butachlor, as measured by bioassay with barnyardgrass, was significantly enhanced by increasing temperatures to 32 C, making the soil alkaline, flooding, introducing relatively high levels of organic matter and by allowing exposure of more than four weeks. Total degradation of butachlor to C02 was enhanced also by high temperatures and length of exposure but was inhibited to a certain extent by flooding. Soil produced metabolites, of which three were soluble in certain organic solvents and five were water soluble, were also influenced by environmental factors, temperature and length of exposure being most significant. Flooding influenced the formation of certain metabolites soluble in organic solvent but did not influence the presence or amounts of water soluble metabolites

    A SURVEY FOR ODONTOCETE CETACEANS OFF KAUA‘I AND NI‘IHAU, HAWAI‘I, DURING OCTOBER AND NOVEMBER 2005: EVIDENCE FOR POPULATION STRUCTURE AND SITE FIDELITY

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    Considerable uncertainty exists regarding population structure and population sizes of most species of odontocetes in the Hawaiian Islands. A small-boat based survey for odontocetes was undertaken off the islands of Kaua‘i and Ni‘ihau in October and November 2005 to photoidentify individuals and collect genetic samples for examining stock structure. Field effort on 24 days covered 2,194 km of trackline. Survey coverage was from shallow coastal waters out to over 3,000 m depth, though almost half (47%) was in waters less than 500 m in depth. There were 56 sightings of five species of odontocetes: spinner dolphins (30 sightings); bottlenose dolphins (14 sightings); short-finned pilot whales (6 sightings); rough-toothed dolphins (5 sightings); and pantropical spotted dolphins (1 sighting). One hundred and five biopsy samples were collected and 14,960 photographs were taken to document morphology and for individual photo-identification. Photographs of distinctive individuals of three species (bottlenose dolphins, 76 identifications; rough-toothed dolphins, 157 identifications; short-finned pilot whales, 68 identifications) were compared to catalogs of these species from a survey off Kaua‘i and Ni‘ihau in 2003, as well as from efforts off O‘ahu, Maui/Lana‘i and the island of Hawai‘i. Within- and between-year matches were found for all three species with individuals previously identified off Kaua‘i and Ni‘ihau, though no matches were found with individuals off any of the other islands. This suggests site fidelity to specific island areas, and population structure among island areas for all three species. Movements of photographically identified bottlenose dolphins were documented between deep water areas off the islands of Kaua‘i and Ni‘ihau, as well as between shallow (\u3c350 m) and deep (\u3e350 m) waters. A lack of sightings or reports of false killer whales off Kaua‘i or Ni‘ihau during our study, combined with documented movements among the other main Hawaiian Islands, suggest that there is no “resident” population of false killer whales that inhabits waters only off Kaua‘i or Ni‘iha

    Arousal Effects on Pupil Size, Heart Rate, and Skin Conductance in an Emotional Face Task

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    Arousal level changes constantly and it has a profound influence on performance during everyday activities. Fluctuations in arousal are regulated by the autonomic nervous system, which is mainly controlled by the balanced activity of the parasympathetic and sympathetic systems, commonly indexed by heart rate (HR) and galvanic skin response (GSR), respectively. Although a growing number of studies have used pupil size to indicate the level of arousal, research that directly examines the relationship between pupil size and HR or GSR is limited. The goal of this study was to understand how pupil size is modulated by autonomic arousal. Human participants fixated various emotional face stimuli, of which low-level visual properties were carefully controlled, while their pupil size, HR, GSR, and eye position were recorded simultaneously. We hypothesized that a positive correlation between pupil size and HR or GSR would be observed both before and after face presentation. Trial-by-trial positive correlations between pupil diameter and HR and GSR were found before face presentation, with larger pupil diameter observed on trials with higher HR or GSR. However, task-evoked pupil responses after face presentation only correlated with HR. Overall, these results demonstrated a trial-by-trial relationship between pupil size and HR or GSR, suggesting that pupil size can be used as an index for arousal level involuntarily regulated by the autonomic nervous system

    The Availability Heuristic, Intuitive Cost-Benefit Analysis, and Climate Change

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    Because risks are on all sides of social situations, it is not possible to be “precautionary” in general. The availability heuristic ensures that some risks stand out as particularly salient, whatever their actual magnitude. Taken together with intuitive cost-benefit balancing, the availability heuristic helps to explain differences across groups, cultures, and even nations in the assessment of precautions to reduce the risks associated with climate change. There are complex links among availability, social processes for the spreading of information, and predispositions. If the United States is to take a stronger stand against climate change, it is likely to be a result of available incidents that seem to show that climate change produces serious and tangible harm

    Mobility and kinship in the world’s first village societies

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    Around 10,000 y ago in southwest Asia, the cessation of a mobile lifestyle and the emergence of the first village communities during the Neolithic marked a fundamental change in human history. The first communities were small (tens to hundreds of individuals) but remained semisedentary. So-called megasites appeared soon after, occupied by thousands of more sedentary inhabitants. Accompanying this shift, the material culture and ancient ecological data indicate profound changes in economic and social behavior. A shift from residential to logistical mobility and increasing population size are clear and can be explained by either changes in fertility and/or aggregation of local groups. However, as sedentism increased, small early communities likely risked inbreeding without maintaining or establishing exogamous relationships typical of hunter-gatherers. Megasites, where large populations would have made endogamy sustainable, could have avoided this risk. To examine the role of kinship practices in the rise of megasites, we measured strontium and oxygen isotopes in tooth enamel from 99 individuals buried at Pınarbaşı, Boncuklu, and Çatalhöyük (Turkey) over 7,000 y. These sites are geographically proximate and, critically, span both early sedentary behaviors (Pınarbaşı and Boncuklu) and the rise of a local megasite (Çatalhöyük). Our data are consistent with the presence of only local individuals at Pınarbaşı and Boncuklu, whereas at Çatalhöyük, several nonlocals are present. The Çatalhöyük data stand in contrast to other megasites where bioarchaeological evidence has pointed to strict endogamy. These different kinship behaviors suggest that megasites may have arisen by employing unique, community-specific kinship practices

    Mobility and kinship in the world's first village societies

    Get PDF
    Around 10,000 y ago in southwest Asia, the cessation of a mobile lifestyle and the emergence of the first village communities during the Neolithic marked a fundamental change in human history. The first communities were small (tens to hundreds of individuals) but remained semisedentary. So-called megasites appeared soon after, occupied by thousands of more sedentary inhabitants. Accompanying this shift, the material culture and ancient ecological data indicate profound changes in economic and social behavior. A shift from residential to logistical mobility and increasing population size are clear and can be explained by either changes in fertility and/or aggregation of local groups. However, as sedentism increased, small early communities likely risked inbreeding without maintaining or establishing exogamous relationships typical of hunter-gatherers. Megasites, where large populations would have made endogamy sustainable, could have avoided this risk. To examine the role of kinship practices in the rise of megasites, we measured strontium and oxygen isotopes in tooth enamel from 99 individuals buried at Pınarbaşı, Boncuklu, and Çatalhöyük (Turkey) over 7,000 y. These sites are geographically proximate and, critically, span both early sedentary behaviors (Pınarbaşı and Boncuklu) and the rise of a local megasite (Çatalhöyük). Our data are consistent with the presence of only local individuals at Pınarbaşı and Boncuklu, whereas at Çatalhöyük, several nonlocals are present. The Çatalhöyük data stand in contrast to other megasites where bioarchaeological evidence has pointed to strict endogamy. These different kinship behaviors suggest that megasites may have arisen by employing unique, community-specific kinship practices

    Best practice guidelines for cetacean tagging

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    Animal-borne electronic instruments (tags) are valuable tools for collecting information on cetacean physiology, behaviour and ecology, and for enhancing conservation and management policies for cetacean populations. Tags allow researchers to track the movement patterns, habitat use andother aspects of the behaviour of animals that are otherwise difficult to observe. They can even be used to monitor the physiology of a tagged animal within its changing environment. Such tags are ideal for identifying and predicting responses to anthropogenic threats, thus facilitating the development of robust mitigation measures. With the increasing need for data best provided by tagging and the increasing availability of tags, such research is becoming more common. Tagging can, however, pose risks to the health and welfare of cetaceans and to personnel involved in tagging operations. Here we provide ‘best practice’ recommendations for cetacean tag design, deployment and follow-up assessment of tagged individuals, compiled by biologists and veterinarians with significant experience in cetacean tagging. This paper is intended to serve as a resource to assist tag users, veterinarians, ethics committees and regulatory agency staff in the implementation of high standards of practice, and to promote the training of specialists in this area. Standardised terminology for describing tag design and illustrations of tag types and attachment sites are provided, along with protocols for tag testing and deployment (both remote and through capture-release), including training of operators. The recommendations emphasise the importance of ensuring that tagging is ethically and scientifically justified for a particular project and that tagging only be used to address bona fide research or conservation questions that are best addressed with tagging, as supported by an exploration of alternative methods. Recommendations are provided for minimising effects on individual animals (e.g. through careful selection of the individual, tag design and implant sterilisation) and for improving knowledge of tagging effects on cetaceans through increased post-tagging monitoring.Publisher PDFPeer reviewe

    Class Actions: Aggregation, Amplification, and Distortion

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