scholarly journals Experimental Studies of Carpenter Bee (Xylocopa: Apidae) Thorax Mechanics During Defensive Buzzing

2021 ◽  
Author(s):  
Mark Jankauski ◽  
Cailin Casey ◽  
Chelsea M Heveran ◽  
Kathryn Busby ◽  
Stephen Buchmann
Keyword(s):  
Longitudinal Muscle ◽  
Experimental Studies ◽  
Force Production ◽  
Muscle Group ◽  
Stretch Activation ◽  
Carpenter Bee ◽  
Velocity Amplitude ◽  
Flight Muscles ◽  
Ventral Muscle ◽  
Insight Into

Bees and other Hymenoptera utilize thorax vibration to realize an extensive range of behaviors ranging from flight to pollination. Strong indirect flight muscles contract to deform the thoracic walls and the resulting oscillation is sustained through a mechanism called stretch activation. While the mechanics of the insect thorax and muscles have been studied extensively during flight, relatively little is known about the thorax mechanics during non-flight behaviors. In this work, we investigate the thorax mechanics of the carpenter bee Xylocopa californica during defensive buzzing. During defensive buzzing, the insect folds its wings over its abdomen and rapidly fires it flight muscles, resulting in a loud audible buzz and large forces intended to deter predators. We devised a novel experiment to measure thorax oscillation and directional force production from a defensively buzzing carpenter bee. The largest peak forces were on average 175 mN and were oriented with the insect's dorsal-ventral muscle group. Peak forces oriented with the insect's dorsal-longitudinal muscle group averaged 117 mN. Thorax velocities were about 90 mm s^-1 p-p and velocity amplitude was positively correlated to peak force. Thorax oscillation frequency averaged 132 Hz but was highly variable both within individuals and across the tested population. From our measurements, we estimated the peak mechanical power required by defensive buzzing at 8.7 mW, which we hypothesize is greater than the power required during flight. Overall, this study provides insight into the function and capabilities of the Hymenopteran indirect flight muscle during non-flight behaviors.

scholarly journals Shedding light on the nature of the catalytically active species in photocatalytic reactions using Bi2O3 semiconductor

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Paola Riente ◽  
Mauro Fianchini ◽  
Patricia Llanes ◽  
Miquel A. Pericàs ◽  
Timothy Noël
Keyword(s):  
Experimental Studies ◽  
Heterogeneous Photocatalysis ◽  
Active Species ◽  
Organic Transformations ◽  
Alkyl Bromides ◽  
Catalytically Active ◽  
Visible Light Driven ◽  
Photocatalytic Reactions ◽  
Insight Into ◽  
Photocatalytic Processes

AbstractThe importance of discovering the true catalytically active species involved in photocatalytic systems allows for a better and more general understanding of photocatalytic processes, which eventually may help to improve their efficiency. Bi2O3 has been used as a heterogeneous photocatalyst and is able to catalyze several synthetically important visible-light-driven organic transformations. However, insight into the operative catalyst involved in the photocatalytic process is hitherto missing. Herein, we show through a combination of theoretical and experimental studies that the perceived heterogeneous photocatalysis with Bi2O3 in the presence of alkyl bromides involves a homogeneous BinBrm species, which is the true photocatalyst operative in the reaction. Hence, Bi2O3 can be regarded as a precatalyst which is slowly converted in an active homogeneous photocatalyst. This work can also be of importance to mechanistic studies involving other semiconductor-based photocatalytic processes.

In-Plane Asymmetries on the Ge(111)-c(2×8) Surface Mapped with the Scanning Tunneling Microscope

1992 ◽  
Vol 295 ◽  
Author(s):  
P. Molinàs-Mata ◽  
J. Zegenhagen ◽  
M. Böhringer ◽  
N. Takeuchi ◽  
A. Selloni
Keyword(s):  
Local Density ◽  
Experimental Studies ◽  
Surface States ◽  
Small Sample ◽  
Constant Current ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Low Energy Electron ◽  
Tunneling Currents ◽  
Insight Into

AbstractWe report on new experimental studies of the Ge(111)-c(2×8) reconstruction performed with low-energy electron diffraction. (LEED) and scanning tunneling microscopy (STM). Weak quarter-order reflections are present in the c(2 × 8) LEED pattern in agreement with previous observations and results of ab initio calculations. In order to gain insight into the predicted splitting of dangling bond states, we compare constant current topographs (CCT's) performed at high-tunneling currents (40.nA) with first-principles calculations of the local density of states (LDOS) 1Å above the surface adatoms and obtain good qualitative agreement. We finally discuss to what extent the STM CCT's at high tunneling currents (small sample-tip distances (STD)) are sensitive to surface states outside the Г point.

Embracing multidimensionality in phonological analysis

2021 ◽  
Vol 38 (1) ◽  
pp. 101-139
Author(s):  
Abigail C. Cohn ◽  
Margaret E. L. Renwick
Keyword(s):  
Native Speaker ◽  
Experimental Studies ◽  
Spoken Language ◽  
Iterative Approach ◽  
Full Spectrum ◽  
Multiple Factors ◽  
Multiple Data ◽  
Language Data ◽  
Corpus Data ◽  
Insight Into

Abstract We pursue the idea, implicit in much current phonological research, that understanding the multiple factors that shape speech production and perception is within the purview of phonology. In particular, increased access to naturalistic data has highlighted the multidimensional reality of variation in spoken language. At the same time, longstanding methods of doing phonology – including impressionistic analysis, and laboratory and experimental studies – remain crucial to understanding native speaker competence and grammar. We advocate for an expanded methodological toolbox in phonological analysis, using an iterative approach that crucially includes naturalistic corpus data. Integrating across multiple data sources offers fuller insight into the nature of the phonological system and native speaker-hearer ability. Several case studies highlight findings gained through linked, iterative studies, showing the importance of naturalistic data for a richer understanding of phonological phenomena, and leading us to reflect on desiderata for corpora to reveal speaker-specific patterns in fine phonetic detail and variability, which we argue are part of a speaker-hearer’s phonological competence. Phonological analysis that embraces the full spectrum of variation in spoken language data (from categorical to gradient, and systematic to sporadic) contributes to a deeper understanding of phonology in this richer sense.

Cytoskeletal proteins of insect muscle: location of zeelins in Lethocerus flight and leg muscle

1994 ◽  
Vol 107 (5) ◽  
pp. 1115-1129 ◽  
Author(s):  
C. Ferguson ◽  
A. Lakey ◽  
A. Hutchings ◽  
G.W. Butcher ◽  
K.R. Leonard ◽  
...  
Keyword(s):  
Insect Flight ◽  
Regular Structure ◽  
Thick Filament ◽  
Cytoskeletal Proteins ◽  
Stretch Activation ◽  
Insect Muscle ◽  
Thick Filaments ◽  
Flight Muscles ◽  
Leg Muscle ◽  
Low Ionic Strength

Asynchronous insect flight muscles produce oscillatory contractions and can contract at high frequency because they are activated by stretch as well as by Ca2+. Stretch activation depends on the high stiffness of the fibres and the regular structure of the filament lattice. Cytoskeletal proteins may be important in stabilising the lattice. Two proteins, zeelin 1 (35 kDa) and zeelin 2 (23 kDa), have been isolated from the cytoskeletal fraction of Lethocerus flight muscle. Both zeelins have multiple isoforms of the same molecular mass and different charge. Zeelin 1 forms micelles and zeelin 2 forms filaments when renatured in low ionic strength solutions. Filaments of zeelin 2 are ribbons 10 nm wide and 3 nm thick. The position of zeelins in fibres from Lethocerus flight and leg muscle was determined by immunofluorescence and immunoelectron microscopy. Zeelin 1 is found in flight and leg fibres and zeelin 2 only in flight fibres. In flight myofibrils, both zeelins are in discrete regions of the A-band in each half sarcomere. Zeelin 1 is across the whole A-band in leg myofibrils. Zeelins are not in the Z-disc, as was thought previously, but migrate to the Z-disc in glycerinated fibres. Zeelins are associated with thick filaments and analysis of oblique sections showed that zeelin 1 is closer to the filament shaft than zeelin 2. The antibody labelling pattern is consistent with zeelin molecules associated with myosin near the end of the rod region. Alternatively, the position of zeelins may be determined by other A-band proteins. There are about 2.0 to 2.5 moles of myosin per mole of each zeelin. The function of these cytoskeletal proteins may be to maintain the ordered structure of the thick filament.

scholarly journals Terrestrial force production by the limbs of a semi-aquatic salamander provides insight into the evolution of terrestrial locomotor mechanics

2021 ◽  
Author(s):  
Sandy Momoe Kawano ◽  
Richard W. Blob
Keyword(s):  
Adult Life ◽  
Force Production ◽  
Rear Wheel ◽  
Ambystoma Tigrinum ◽  
Terrestrial Locomotion ◽  
Hind Limbs ◽  
Wheel Drive ◽  
Reaction Forces ◽  
Pleurodeles Waltl ◽  
Insight Into

Amphibious fishes and salamanders are valuable functional analogs for vertebrates that spanned the water-to-land transition. However, investigations of walking mechanics have focused on terrestrial salamanders and, thus, may better reflect the capabilities of stem tetrapods that were already terrestrial. The earliest tetrapods were aquatic, so salamanders that are not primarily terrestrial may yield more appropriate data for modelling the incipient stages of terrestrial locomotion. In the present study, locomotor biomechanics were quantified from semi-aquatic Pleurodeles waltl, a salamander that spends most of its adult life in water, and then compared to a primarily terrestrial salamander (Ambystoma tigrinum) and semi-aquatic fish (Periophthalmus barbarus) to evaluate whether walking mechanics show greater similarity between species with ecological versus phylogenetic similarities. Ground reaction forces (GRFs) from individual limbs or fins indicated that the pectoral appendages of each taxon had distinct patterns of force production, but hind limb forces were comparable between the salamanders. The rate of force development ('yank') was sometimes slower in P. waltl but generally comparable between the three species. Finally, medial inclination of the GRF in P. waltl was intermediate between semi-aquatic fish and terrestrial salamanders, potentially elevating bone stresses among more aquatic taxa as they move on land. These data provide a framework for modelling stem tetrapods using an earlier stage of quadrupedal locomotion that was powered primarily by the hind limbs (i.e., "rear-wheel drive"), and reveal mechanisms for appendages to generate propulsion in three locomotor strategies that are presumed to have occurred across the water-to-land transition in vertebrate evolution.

Flight muscle and flight activity of melon fly, Bactrocera cucurbitae (Diptera: Tephritidae)

2021 ◽  
Vol 30 (2) ◽  
pp. 179-185
Author(s):  
Farhana Ferdousi ◽  
Shanjida Sultana ◽  
Tangin Akter ◽  
Pinakshi Roy ◽  
Shefali Begum
Keyword(s):  
Longitudinal Muscle ◽  
Flight Muscle ◽  
Flight Activity ◽  
The Other ◽  
Bactrocera Cucurbitae ◽  
Male And Female ◽  
Melon Fly ◽  
Length Width ◽  
Flight Muscles ◽  
The Mean

The flight activity and flight muscle of the melon fly, Bactrocera cucurbitae (Coquillett) (Diptera: Tephritidae) were observed. The Tethered technique was used to observe the flight activity in this study. The flight activity, and wing and flight muscles were compared between male and female melon flies. The results indicate that the female was relatively better and strong flier than the male. The mean duration of the flight activity of the females was 13.90 min/hour and of the males was 7.12 min./hour. The mean length, width, volume of wings of the males were 6.07 mm, 2.67 mm and 10.99 mm³, respectively. On the other hand, the mean length, width and volume of the wings of females were 7.07 mm, 2.87 mm and 15.60 mm³, respectively. In case of wing muscles, the mean volume of dorsal longitudinal muscle (DLM) in male and female was found 5.20 mm³ and 5.67 mm³, respectively. The mean length of flight wing muscle of male and female was 2.22 and 2.23 mm, respectively and the mean breadth of male and female was 1.65 and 1.77 mm, respectively. Dhaka Univ. J. Biol. Sci. 30(2): 179-185, 2021 (July)

Neural Foundations of Variability in Attachment

2017 ◽  
Author(s):  
Allyson J. Bennett ◽  
William D. Hopkins ◽  
Ruth Feldman ◽  
Valeria Gazzola ◽  
Jay Giedd ◽  
...  
Keyword(s):  
Brain Development ◽  
Animal Studies ◽  
Experimental Studies ◽  
Theory Development ◽  
Single Type ◽  
Negative Consequences ◽  
Cultural Contexts ◽  
The Social ◽  
Insight Into

Neuroscience offers insight into processes that support the development of the social brain within the cultural contexts that permit attachment relationships to form. Both human and nonhuman animal studies are critical to inform theory development and hypothesis testing via descriptive and experimental studies. A scientifically valid evolutionary theory is necessary to account for the remarkable diversity of parenting systems across human and many nonhuman animals. This chapter examines the neural foundations of attachment and poses critical questions that relate to the initiation of this relationship: How does attachment interface with brain development? What is the interplay between attachment and brain development (including elements of bidirectionality)? Are there negative consequences associated with variation in attachment, and are they reversible? Rather than conceptualizing attachment in terms of a single type of relationship, or a rigid developmental channel, this chapter proposes that an expanded consideration of variation is necessary to understand the neural foundations of infant-caregiver relationships, and the role of those relationships in developing competence across the life span. This approach will permit identification of common neurobiological elements of attachment as well as the remarkable plasticity and diversity within and across individuals, cultures, and species.

Fuzzy Logic Classifiers and Models in Quantitative Software Engineering

2009 ◽  
pp. 3142-3159 ◽  
Author(s):  
Witold Pedrycz ◽  
Giancarlo Succi
Keyword(s):  
Software Engineering ◽  
Software Quality ◽  
Software Metrics ◽  
Experimental Studies ◽  
Genetic Optimization ◽  
Learning Abilities ◽  
Optimization Framework ◽  
Logic Models ◽  
Software Modules ◽  
Insight Into

The learning abilities and high transparency are the two important and highly desirable features of any model of software quality. The transparency and user-centricity of quantitative models of software engineering are of paramount relevancy as they help us gain a better and more comprehensive insight into the revealed relationships characteristic to software quality and software processes. In this study, we are concerned with logic-driven architectures of logic models based on fuzzy multiplexers (fMUXs). Those constructs exhibit a clear and modular topology whose interpretation gives rise to a collection of straightforward logic expressions. The design of the logic models is based on the genetic optimization and genetic algorithms, in particular. Through the prudent usage of this optimization framework, we address the issues of structural and parametric optimization of the logic models. Experimental studies exploit software data that relates software metrics (measures) to the number of modifications made to software modules.

The Impact of Bedside Technology on Patients' Well-Being

2011 ◽  
Vol 5 (1) ◽  
pp. 43-51 ◽  
Author(s):  
Karin Tanja-Dijkstra
Keyword(s):  
Medical Equipment ◽  
Emotional State ◽  
Healing Process ◽  
Experimental Studies ◽  
Well Being ◽  
Single Factor ◽  
Healthcare Design ◽  
Healthcare Environment ◽  
The Impact ◽  
Insight Into

Objective: This paper presents a study to gain insight into the effects of the visibility of medical equipment on the well-being of patients. Background: Encounters with healthcare situations are characterized by stress and anxiety. The presence of wires, tubes, and monitors near the bedside may contribute to these feelings. One of the trends in healthcare design is to organize the headwalls of patient rooms in such a way as to reduce clutter and minimize the visibility of medical equipment, but no experimental studies are available that investigate the effects of the visibility of medical equipment in patient rooms. Methods: This experiment employed a single-factor between-subjects design (medical equipment visible vs. medical equipment out of sight) exposing participants ( n = 42) to a scenario and a picture of a hospital room. Results: Placing medical equipment out of sight leads to reduced feelings of stress in patients. This stress-reducing effect is mediated by feelings of pleasure. Placing medical equipment out of sight leads to a more positive emotional state, which in turn leads to feelings of reduced stress in patients. Moreover, placing equipment out of sight leads to people having more trust in the healthcare provider. Conclusions: The current study emphasizes the importance of the built healthcare environment and shows what role the visibility of medical equipment can play in the healing process of patients.

scholarly journals Serotonin modulates muscle function in the medicinal leech Hirudo verbana

2011 ◽  
Vol 7 (6) ◽  
pp. 885-888 ◽  
Author(s):  
Shannon P. Gerry ◽  
David J. Ellerby
Keyword(s):  
Body Wall ◽  
Longitudinal Muscle ◽  
Force Production ◽  
Physiological Saline ◽  
The Body ◽  
Hirudo Verbana ◽  
Work Production ◽  
Large Length ◽  
Body Wall Muscles

The body wall muscles of sanguivorous leeches power mechanically diverse behaviours: suction feeding, crawling and swimming. These require longitudinal muscle to exert force over an extremely large length range, from 145 to 46 per cent of the mean segmental swimming length. Previous data, however, suggest that leech body wall muscle has limited capacity for force production when elongated. Serotonin (5-HT) alters the passive properties of the body wall and stimulates feeding. We hypothesized that 5-HT may also have a role in allowing force production in elongated muscle by changing the shape of the length–tension relationship (LTR). LTRs were measured from longitudinal muscle strips in vitro in physiological saline with and without the presence of 10 µM 5-HT. The LTR was much broader than previously measured for leech muscle. Rather than shifting the LTR, 5-HT reduced passive muscle tonus and increased active stress at all lengths. In addition to modulating leech behaviour and passive mechanical properties, 5-HT probably enhances muscle force and work production during locomotion and feeding.

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