14 research outputs found
The use of pigs vocalisation structure to assess the quality of human-pig relationship
Studying human-animal interactions in domestic species and how they affect the establishment of a positive Human-Animal Relationship (HAR) may help us improve animal welfare and better understand the evolution of interspecific interactions associated with the domestication process. Understanding and describing the quality of an HAR requires information on several aspects of the animal biology and emotional states (social, spatial and postural behaviours, physiological and cognitive states). Growing evidence shows that acoustic features of animal vocalisations may be indicators of emotional states. Here, we tested the hypothesis that vocal structure may indicate the quality of HAR. At weaning, 30 piglets were positively handled by an experimenter who talked to and physically interacted with them three times a day, while 30 other piglets only received the contact necessary for proper husbandry. After two weeks, we recorded the behaviours and vocalisations produced in the presence of the static experimenter for 5 min. We repeated this test two weeks later, after a conditioning period during which human presence with additional positive contacts was used as a reward for all piglets. We hypothesized this conditioning period would lead to a positive human-piglet relationship for all piglets. As expected, piglets that were positively handled at weaning expressed a higher attraction toward the experimenter, and, after the conditioning, piglets that were not positively handled at weaning expressed a similar level of attraction than the positively handled ones. Piglets positively handled at weaning produced shorter grunts than the other ones, regardless of the context of recording, which may indicate a more positive affect. During reunions with the static experimenter, a more positive HAR was associated with a decrease in vocal reactivity to human proximity. However, during reunions with the experimenter providing additional positive contacts and over the conditioning, spatial proximity to the human systematically triggered shorter and higher pitched grunts, which may indicate a more positive emotional state. Results first show that changes in vocal structure are consistent with indicators of positive states in the presence of a human. Second, these changes are stronger when the human positively interact with the piglets, supposedly emphasizing a higher positive arousal state during these interactions. We show that vocalisation structure may be a promising indicator of the quality of human-pig relationship
Communication Acoustique chez les Passereaux Femelles:Fonctions, Flexibilité et Plasticité des cris
The theory of sexual selection has drastically oriented research on acoustic communication in birds: males learn and sing conspicuous songs and females choose. Consequently, (1) female vocal production has been neglected, (2) birdcalls (most bird social communication) have been understudied. Birdcalls were supposed to be non-learned and no effect of the environment was expected on their structure (no flexibility, no learning). I thus focused my thesis on vocal flexibility (short-term) and vocal plasticity (developmental) of female vocalizations (mainly calls). I studied two contexts in which both sexes produce vocalizations: intrapair communication at the nest and parent-offspring communication. Do pairs express vocal flexibility in their calls in response to environmental noise? Is call development influenced by social environment? I studied two species: the white-throated dippers, Cinclus cinclus. (in which both sexes produce calls and songs) and the zebra finch, Taeniopygia guttata, (in which only males sing but both sexes use the same calls). I showed in both species, that in response to environmental noise, pairs increased the amplitude of their calls or song notes. In dippers, spectral flexibility was observed in song notes but not in calls. However, zebra finch calls showed spectral flexibility in response to noise. Both sexes showed similar changes in their calls: call spectral flexibility is not sex specific. Last, I showed that the structure of male begging calls changed in response to the early social environment, bringing evidence of early vocal plasticity in males. No change was found in females, showing that they either differ in their plasticity abilities or do not express plasticity because they receive different social feedbacks. My work showed that females and males show vocal flexibility but their vocal developmental trajectories may differ. Calls are thus good study objects to investigate sexual dimorphism in vocal behaviour.La théorie de la sélection sexuelle a drastiquement orienté l’effort de recherche sur la communication acoustique chez les oiseaux: les mâles apprennent et produisent des chants élaborés et les femelles choisissent. Par conséquent (1) la production vocale chez les femelles a été négligée, (2) les cris (la majorité de la communication sociale) ont été peu étudiés. Contrairement aux chants, les cris ont été considérés comme innés et aucun effet de l’environnement sur leur structure n’était attendu. J’ai donc posé la question de la flexibilité vocale (court-terme) et de la plasticité vocale (au cours du développement) chez les femelles, en étudiant les cris majoritairement. J’ai étudié deux contextes où les deux sexes vocalisent: la communication dans le couple au nid et la communication parent-jeunes. Les vocalisations produites au nid par les couples montrent-elles de la flexibilité en réponse au bruit? Le développement des cris est-il influencé par l’environnement social ? J’ai travaillé sur deux espèces: le cincle plongeur, Cinclus cinclus et le diamant mandarin, Taeniopygia guttata. Chez les deux espèces, en réponse au bruit, les couples augmentent l’amplitude de leurs vocalisations. Chez le cincle une variation de la structure spectrale est observée dans les notes de chant mais pas dans les cris. Chez le diamant mandarin, les cris montrent des changements de leur structure spectrale: ils peuvent donc être flexibles en réponse au bruit. Les changements sont similaires chez les femelles et les mâles : la flexibilité n’est pas spécifique du sexe. Enfin, j’ai montré que l’environnement social précoce influence le développement des cris de quémande alimentaire chez le diamant mandarin : il existe une plasticité précoce des cris chez les mâles. J’ai montré que les femelles expriment des degrés de flexibilité similaires aux mâles mais que leur développement vocal peut prendre des trajectoires différentes. Les cris sont de bons objets de recherche pour étudier des variations de comportement vocal liées au sexe
Vocal behaviour of mates at the nest in the White-throated Dipper Cinclus cinclus: contexts and structure of vocal interactions, pair-specific acoustic signature
International audienc
Scrapbook of Louise Pierce. Image 028
https://repository.wellesley.edu/studentsbpierce/1079/thumbnail.jp
Experimental Investigation on Characteristics of High-Speed Milling of 6061 Aluminum Alloy
高速切削是一種利用淺切深、高速進給和高切削速度的方式進行加工,不但可以大幅降低加工成本與時間外,並有熱變形小與切削力低的優點。本文首先針對文獻不足處進行刀刃運動路徑分析,並推導出切屑形狀、切削力和側銑表面粗糙度之理論模式;另外以輕合金加工所常用之6061-T651鋁合金進行實驗,文中以田口實驗設計法規劃面銑、槽銑和側銑三種銑削方式進行實驗驗證與製程最佳化參數之探討,除了將所獲取的銑削力和銑削動力以及表面粗糙度進行探討外,並根據表面粗糙度與銑削力的品質特性,提供最佳的製程參數組合。
本研究透過MAKINO-A55工具機進行實驗,實驗結果發現,表面粗糙度實驗值與理論值有所差異,面銑為1.2-3倍,槽銑為10-12倍,而側銑則為20倍左右;同時亦發現高速切削的確可得到相當優異的表面,如面銑Ra <0.5m,槽銑Ra <2m,而側銑Ra <0.4m。又經田口法分析後,當面銑之刀具直徑愈大時,則表面品質下降;而表面品質最佳的製程參數組合是每刃進給0.06mm/tooth、切削速度850m/min、切削深度0.2mm、刀具直徑50mm、切削寬度與刀具直徑比為70%;而在銑削深度0.2mm時銑削力最小,此與表面粗糙度的最佳參數表現不謀而合。另槽銑實驗則發現每刃進給影響最大,較小的進給量可以獲得較佳的表面;至於最佳表面粗糙度的製程參數組合為每刃進給0.035mm/tooth、切削速度410m/min、切削深度0.1mm和刀具直徑16mm。側銑表面粗糙度最佳參數組合則為每刃進給0.035mm/tooth、切削速度360m/min、切削深度8mm、切削寬度0.3mm和刀具直徑20mm,其中影響最大的因子亦為每刃進給。
再者,當切深愈大時,除了銑削力相對增大外,刃口積屑緣的情形也會相對增加。另以頻譜分析亦發現表面粗糙度與銑削力之頻譜相當契合,此現象應值得再深入探討。High-speed cutting (HSC) is a machining method with low cutting depth, high feed rate and high cutting speed. It takes the advantages of lower machining time and cost as well as low thermal deformation and low cutting force. This thesis first analyzes the trajectory of a cutting edge and then drives the shape of chips, cutting force and surface roughness base on the trajectory. Experiments using the commonly used aluminum alloy 6061-T651 on a MAKINO-A55 machine tool is then designed and conducted to verity the surface roughness and to find the process parameters for best surface roughness. Experiments are designed by the Taguchi method in order to minimize the number of experiments.
The result shows the real surface roughness is higher than the ideal one from 1.2 to 3 times for face milling; 10 to 12 times for slot milling and about 20 times worse for side milling. It also shows good surface finish can be easily achieved by HSC, for example, Ra<0.5m for face milling; Ra<2m for slot milling, and Ra<0.4m for side milling. Process parameters for best surface roughness are allocated based on the ANOVA (ANalysis Of VAriance) and the S/N (Signal to Noise) ratio. It is found that the tool diameter plays as the most important factor in face milling. The surface quality become worse as it increases. Minimum cutting force is obtained at depth of cut being 0.2mm which is consistent with the best surface finish. The feed per cutting edge, on the other hand, has been found as the most affective factor in slot milling and in side milling. Better surface finish can be achieved by reducing feed per cutting edge.
Analysis of experimental data further finds that cutting forces and built-up edges increase as the depth of cut increases. Moreover, it is also found strong co-relation between the surface roughness and cutting force from frequency spectrum. This phenomenon is worthy of further investigation.第一章 緒論
1.1 緣起
1.2 文獻回顧
1.3 研究方法
1.4 本文大綱
第二章 切削分析
2.1 銑削刀刃運動分析
2.2 銑削力分析
2.3 銑削動力分析
2.4 表面粗度分析
2.5 移除率與加工時間計算
2.6 理論式在高速銑削之適用性探討
第三章 高速銑削實驗設計與架設
3.1 田口實驗設計法簡介
3.1.1 高速銑削實驗規劃程序
3.2 實驗系統架設
3.3 實驗量測設備
第四章 實驗結果與分析
4.1 高速面銑削
4.1.1 表面粗度量測結果與分析
4.1.2 表面粗度變異數分析
4.1.3 面銑表面粗度驗證實驗
4.1.4 銑削力量測結果與分析
4.1.5 銑削力變異數分析
4.1.6 高速面銑之銑削行為分析與探討
4.2 高速端銑削-槽銑
4.2.1 表面粗度量測結果與分析
4.2.2 表面粗度變異數分析
4.2.3 端槽銑表面粗度驗證實驗
4.2.4 銑削力量測結果與分析
4.2.5 銑削力變異數分析
4.2.6 高速端-槽銑之銑削行為分析與探討
4.3 高速端銑削-側銑
4.3.1 表面粗度量測結果與分析
4.3.2 表面粗度變異數分析
4.3.3 端側銑表面粗度驗證實驗
4.3.4 銑削力量測結果與分析
4.3.5 銑削力變異數分析
4.3.6 高速端-側銑之銑削行為分析與探討
4.4 實驗觀察建議
第五章 結論與未來展望
5.1 結論
5.2 未來展望
參考文獻
附錄A 表面粗度相關理論推導
附錄B 銑削模擬系統建構
附錄C 刀具條件參考值
附錄D 實驗系統設備規格
附錄E 實驗量測設備規格
附錄F 表面粗度之量測準則
附錄G 銑削實驗之數控程式碼
附錄H 實驗條件與平均銑削力週期分佈關係圖
作者簡
Progress and prospects in gender visibility at SMBE annual meetings
Reduced visibility of women in science is thought to be one of the causes of their underrepresentation among scientists, in particular at senior positions. Visibility is achieved through publications, and through conference attendance and presentations. Here, we investigated gender differences in visibility at the annual meetings of the Society of Molecular Biology and Evolution. The analysis of meeting programs showed a regular increase in female speakers for the last 16 years. Data on abstract submission suggest that there are no gender-related preferences in the acceptance of contributed presentations at the most recent meetings. However, data collected on-site in 2015 and 2016 show that women asked only ∼25% of the questions, that is, much less than expected given the female attendance. Understanding the reasons for this pattern is necessary for the development of policies that aim to reduce imbalance in visibility
Vocal negotiation over parental care? Acoustic communication at the nest predicts partners' incubation share
International audienceIn species with biparental care, individuals adjust their workload to that of their partner to either compensate or match its investment. Communication within a pair might be crucial for achieving this adjustment. Zebra finches, Taeniopygia guttata, form life-long monogamous pair bonds, in which partners are highly coordinated and both incubate the eggs. When relieving each other during incubation, partners perform a structured call duet at the nest. If this duet functions to coordinate incubation workload, disrupting the pair's usual nest-relief pattern by delaying the male's return to the nest should affect the structure of the duet. Using domesticated birds breeding in a large aviary, we found that delaying the male's return induced shorter duets with higher call rates. In addition, we tracked the location of individuals with a transponder at the nest and the feeder, and showed that these accelerated duets were associated with an increased haste of the partners to take turns incubating and foraging. Females also spent less time incubating during their subsequent shift, and females' time off-nest was best predicted by their mate's calling behaviour in the previous duet. Taken together, these results suggest that duets may function as ‘vocal negotiation’ over parental care
Songbird mates change their call structure and intra-pair communication at the nest in response to environmental noise
International audienceThe coordination of behaviours between mates is a central aspect of the biology of the monogamous pair bonding in birds. This coordination may rely on intrapair acoustic communication, which is surprisingly poorly understood. Here we examined the impact of an increased level of background noise on intrapair acoustic communication at the nest in the zebra finch, Taeniopygia guttata. We monitored how partners adapted their acoustic interactions in response to a playback of wind noise inside the nestbox during incubation. Both zebra finch parents incubate and use coordinated call duets when they meet at the nest. The incubating parent can vocalize to its partner either outside the nestbox (sentinel duets) or inside the nestbox (relief and visit duets), depending on the context of the meeting. Pairs use these duets to communicate on predation threats (sentinel duets), incubation duties (relief) and other nesting activities (visit duets). Each of these duets probably represents a critical component of pair coordination. In response to the noise playback, partners called less and more rapidly during visit and relief duets. Female and male calls were more regularly and precisely alternated during relief duets. Mates increased the number of visit duets and their spatial proximity during sentinel duets. Furthermore, both females and males produced louder, higher-frequency and less broadband calls. Taken together our results show that birds use several strategies to adjust to noise during incubation, underlining the importance of effective intrapair communication for breeding pairs