scholarly journals On the So-called Constant-lift Reaction of Migratory Locusts

1989 ◽  
Vol 147 (1) ◽  
pp. 111-124 ◽  
Author(s):  
WOLFRAM ZARNACK ◽  
MICHAEL WORTMANN
Keyword(s):  
Body Weight ◽  
Wind Speed ◽  
Wind Tunnel ◽  
Force Transducer ◽  
The Body ◽  
Flight Speed ◽  
Body Angle ◽  
Level Flight ◽  
Tethered Flight ◽  
Thrust Measurement

1. Locusts were fastened to a force transducer in front of a wind tunnel to measure their lift and thrust during tethered flight heading into the wind. The thrust measurement was used to adapt the wind speed to the flight speed of the animals. Thus, the locusts could choose their flight speed freely in the range 0.5–7ms−1. 2. At light intensities of about 0.02 lx (twilight), the locusts generally produced a maximum lift greater than 100% of their body weight. 3. A miniature motor mounted on the force transducer could alter the body angle of the locusts without further interference. Lift was found to be influenced by body angle. No ‘constant-lift reaction’ evoked by exteroceptive information of the aerodynamic flow was found. 4. Flight speed was almost independent of the imposed body angle. 5. Generally, a flight speed of about 3 m s−1 was necessary for level flight. There was no further correlation between lift and flight speed.

WING MOVEMENTS AND LIFT REGULATION IN THE FLIGHT OF DESERT LOCUSTS

1993 ◽  
Vol 182 (1) ◽  
pp. 57-69 ◽  
Author(s):  
M. Wortmann ◽  
W. Zarnack
Keyword(s):  
Body Weight ◽  
Unsteady Aerodynamics ◽  
Movement Patterns ◽  
The Body ◽  
Three Dimensions ◽  
Body Angle ◽  
Wing Movement ◽  
Induced Changes ◽  
Lift Body

1. We simultaneously recorded lift/body weight, flight speed, body angle and 12 variables of wing movement for locusts performing tethered long-term flight with low movement scatter. The movements of the forewings and hindwings were recorded in three dimensions by means of miniature induction coils. 2. By adjusting the body angle, we could reproducibly manipulate lift generation as a consequence of induced changes in the wings' movement patterns. We were therefore able to analyse various relationships between the movement patterns and lift. 3. The most prominent variations of kinematic variables were observed for the forewing movements. The relative lift and the steady angle of pitch were positively correlated but there was a negative correlation between relative lift and pitching amplitude. We found no correlation between relative lift and flapping amplitude. Our results seem to correspond to a new theory about unsteady aerodynamics of oscillating aerofoils. 4. We sometimes observed variations in lagging. 5. The forewing downstroke was delayed by 0–8 ms following the hindwing downstroke. Relative lift was positively correlated to this delay.

scholarly journals Kinematics Measurement and Power Requirements of Fruitflies at Various Flight Speeds

Energies ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 4271
Author(s):  
Hao Jie Zhu ◽  
Mao Sun
Keyword(s):  
The Body ◽  
Flight Speed ◽  
Specific Power ◽  
Flight Performance ◽  
Wingbeat Frequency ◽  
Body Angle ◽  
Flying Insects ◽  
Speed Range ◽  
Full Speed ◽  
Stroke Amplitude

Energy expenditure is a critical characteristic in evaluating the flight performance of flying insects. To investigate how the energy cost of small-sized insects varies with flight speed, we measured the detailed wing and body kinematics in the full speed range of fruitflies and computed the aerodynamic forces and power requirements of the flies. As flight speed increases, the body angle decreases and the stroke plane angle increases; the wingbeat frequency only changes slightly; the geometrical angle of attack in the middle upstroke increases; the stroke amplitude first decreases and then increases. The mechanical power of the fruitflies at all flight speeds is dominated by aerodynamic power (inertial power is very small), and the magnitude of aerodynamic power in upstroke increases significantly at high flight speeds due to the increase of the drag and the flapping velocity of the wing. The specific power (power required for flight divided by insect weigh) changes little when the advance ratio is below about 0.45 and afterwards increases sharply. That is, the specific power varies with flight speed according to a J-shaped curve, unlike those of aircrafts, birds and large-sized insects which vary with flight speed according to a U-shaped curve.

scholarly journals Embodied linearity of speed control in Drosophila melanogaster

2012 ◽  
Vol 9 (77) ◽  
pp. 3260-3267 ◽  
Author(s):  
V. Medici ◽  
S. N. Fry
Keyword(s):  
Control Strategy ◽  
High Speed ◽  
Hierarchical Control ◽  
Speed Control ◽  
Micro Air Vehicles ◽  
The Body ◽  
Flight Speed ◽  
Free Flight ◽  
Body Angle ◽  
Visual Speed

Fruitflies regulate flight speed by adjusting their body angle. To understand how low-level posture control serves an overall linear visual speed control strategy, we visually induced free-flight acceleration responses in a wind tunnel and measured the body kinematics using high-speed videography. Subsequently, we reverse engineered the transfer function mapping body pitch angle onto flight speed. A linear model is able to reproduce the behavioural data with good accuracy. Our results show that linearity in speed control is realized already at the level of body posture-mediated speed control and is therefore embodied at the level of the complex aerodynamic mechanisms of body and wings. Together with previous results, this study reveals the existence of a linear hierarchical control strategy, which can provide relevant control principles for biomimetic implementations, such as autonomous flying micro air vehicles.

scholarly journals Flight kinematics of black-billed magpies and pigeons over a wide range of speeds

1996 ◽  
Vol 199 (2) ◽  
pp. 263-280 ◽  
Author(s):  
B Tobalske ◽  
K Dial
Keyword(s):  
Wind Tunnel ◽  
Aspect Ratio ◽  
Vortex Ring ◽  
High Speed ◽  
Columba Livia ◽  
Flight Speed ◽  
Body Angle ◽  
Scaling Hypothesis ◽  
Wide Range ◽  
Mechanical Power Output

To investigate how birds that differ in morphology change their wing and body movements while flying at a range of speeds, we analyzed high-speed (60 Hz) video tapes of black-billed magpies (Pica pica) flying at speeds of 4-14 m s-1 and pigeons (Columba livia) flying at 6-20 m s-1 in a wind-tunnel. Pigeons had higher wing loading and higher-aspect-ratio wings compared with magpies. Both species alternated phases of steady-speed flight with phases of acceleration and deceleration, particularly at intermediate flight speeds. The birds modulated their wingbeat kinematics among these phases and frequently exhibited non-flapping phases while decelerating. Such modulation in kinematics during forward flight is typical of magpies but not of pigeons in the wild. The behavior of the pigeons may have been a response to the reduced power costs for flight in the closed wind-tunnel relative to those for free flight at similar speeds. During steady-speed flight, wingbeat frequency did not change appreciably with increasing flight speed. Body angle relative to the horizontal, the stroke-plane angles of the wingtip and wrist relative to the horizontal and the angle describing tail spread at mid-downstroke all decreased with increasing flight speed, thereby illustrating a shift in the dominant function of wing flapping from weight support at slow speeds to positive thrust at fast speeds. Using wingbeat kinematics to infer lift production, it appeared that magpies used a vortex-ring gait during steady-speed flight at all speeds whereas pigeons used a vortex-ring gait at 6 and 8 m s-1, a transitional vortex-ring gait at 10 m s-1, and a continuous-vortex gait at faster speeds. Both species used a vortex-ring gait for acceleration and a continuous-vortex gait or a non-flapping phase for deceleration during flight at intermediate wind-tunnel speeds. Pigeons progressively flexed their wings during glides as flight speed increased but never performed bounds. Wingspan during glides in magpies did not vary with flight speed, but the percentage of bounds among non-flapping intervals increased with speed from 10 to 14 m s-1. The use of non-flapping wing postures seemed to be related to the gaits used during flapping and to the aspect ratio of the wings. We develop an 'adverse-scaling' hypothesis in which it is proposed that the ability to reduce metabolic and mechanical power output using flap-bounding flight at fast flight speeds is scaled negatively with body mass. This represents an alternative to the 'fixed-gear' hypothesis previously suggested by other authors to explain the use of intermittent flight in birds. Future comparative studies in the field would be worthwhile, especially if instantaneous flight speeds and within-wingbeat kinematics were documented; new studies in the laboratory should involve simultaneous recording of wing kinematics and aerodynamic forces on the wing.

Flight in Drosophila

1966 ◽  
Vol 44 (3) ◽  
pp. 567-578 ◽  
Author(s):  
STEVEN VOGEL
Keyword(s):  
Wind Tunnel ◽  
Adaptive Significance ◽  
Fruit Flies ◽  
Flight Performance ◽  
Free Flight ◽  
Body Angle ◽  
Control Reaction ◽  
Level Flight ◽  
Lift Control ◽  
Very High

1. Apparatus has been devised to record the principal parameters of the flight performance of tethered fruit-flies in a wind tunnel. 2. Typically these flies achieve level flight (lift = weight) at 200 cm./sec. and a body angle of + 10°. Lift varies directly with body angle except at very high angles; the stroke parameters are invariant with body angle. 3. Evidence is presented suggesting that these measurements are applicable to free flight. 4. The adaptive significance of the absence of a ‘lift-control reaction’ in fruit-flies is discussed.

L-Ascorbic Acid Addition to Chitosan Reduces Body Weight in Overweight Women

2014 ◽  
Vol 84 (1-2) ◽  
pp. 5-11 ◽  
Author(s):  
Eun Y. Jung ◽  
Sung C. Jun ◽  
Un J. Chang ◽  
Hyung J. Suh
Keyword(s):  
Ascorbic Acid ◽  
Body Weight ◽  
Fat Body ◽  
Body Weight Gain ◽  
Skinfold Thickness ◽  
The Body ◽  
Control Group ◽  
Percentage Body Fat ◽  
Overweight Women ◽  
Body Weights

Previously, we have found that the addition of L-ascorbic acid to chitosan enhanced the reduction in body weight gain in guinea pigs fed a high-fat diet. We hypothesized that the addition of L-ascorbic acid to chitosan would accelerate the reduction of body weight in humans, similar to the animal model. Overweight subjects administered chitosan with or without L-ascorbic acid for 8 weeks, were assigned to three groups: Control group (N = 26, placebo, vehicle only), Chito group (N = 27, 3 g/day chitosan), and Chito-vita group (N = 27, 3 g/day chitosan plus 2 g/day L-ascorbic acid). The body weights and body mass index (BMI) of the Chito and Chito-vita groups decreased significantly (p < 0.05) compared to the Control group. The BMI of the Chito-vita group decreased significantly compared to the Chito group (Chito: -1.0 kg/m2 vs. Chito-vita: -1.6 kg/m2, p < 0.05). The results showed that the chitosan enhanced reduction of body weight and BMI was accentuated by the addition of L-ascorbic acid. The fat mass, percentage body fat, body circumference, and skinfold thickness in the Chito and Chito-vita groups decreased more than the Control group; however, these parameters were not significantly different between the three groups. Chitosan combined with L-ascorbic acid may be useful for controlling body weight.

Hand-assisted laparoscopic nephrectomy in morbidly obese patients

2020 ◽  
Vol 99 (6) ◽  
pp. 271-276
Keyword(s):  
Body Weight ◽  
Surgical Technique ◽  
Blood Loss ◽  
Hospital Stay ◽  
Kidney Cancer ◽  
The Body ◽  
Laparoscopic Nephrectomy ◽  
Morbidly Obese ◽  
Obese Patients ◽  
Morbid Obese

Introduction: Prevalence of obesity is 30 % in the Czech Republic and is expected to increase further in the future. This disease complicates surgical procedures but also the postoperative period. The aim of our paper is to present the surgical technique called hand-assisted laparoscopic nephrectomy (HALS), used in surgical management of kidney cancer in morbid obese patients with BMI >40 kg/m2. Methods: The basic cohort of seven patients with BMI >40 undergoing HALS nephrectomy was retrospectively evaluated. Demographic data were analyzed (age, gender, body weight, height, BMI and comorbidities). The perioperative course (surgery time, blood loss, ICU time, hospital stay and early complications), tumor characteristics (histology, TNM classification, tumor size, removed kidney size) and postoperative follow-up were evaluated. Results: The patient age was 38−67 years; the cohort included 2 females and 5 males, the body weight was 117−155 kg and the BMI was 40.3−501 kg/m2. Surgery time was 73−98 minutes, blood loss was 20−450 ml, and hospital stay was 5−7 days; incisional hernia occurred in one patient. Kidney cancer was confirmed in all cases, 48–110 mm in diameter, and the largest removed specimen size was 210×140×130 mm. One patient died just 9 months after the surgery because of metastatic disease; the tumor-free period in the other patients currently varies between 1 and 5 years. Conclusion: HALS nephrectomy seems to be a suitable and safe surgical technique in complicated patients like these morbid obese patients. HALS nephrectomy provides acceptable surgical and oncological results.

HISTOLOGICAL CHANGES IN THE INTESTINES OF POULTRY DURING FODDER INTOXICATION

2020 ◽  
Author(s):  
E.P. Dolgov ◽  
◽  
A.A. Abramov ◽  
E.V. Kuzminova ◽  
E.V. Rogaleva ◽  
...  
Keyword(s):  
Body Weight ◽  
Histological Examination ◽  
Aflatoxin B1 ◽  
Structural Changes ◽  
Clinical Manifestations ◽  
Feed Additives ◽  
The Body ◽  
Histological Changes ◽  
Beet Pulp

The article presents the data on the study of the influence of mycotoxins combination (T-2 toxin at the concentration of 0.095 mg/kg and aflatoxin B1 in the concentration of 0.019 mg/kg) on the body of quails and the results of pharmacocorrection of toxicosis with a complex consisting of beet pulp and lecithin. Structural changes in the intestines of quais at fodder mycotoxicosis are described. The use of antitoxic feed additives in poultry led to a weakening of the action of xenobiotics, which was confirmed by an increase in the safety of poultry and increase in body weight of quails, a decrease in the clinical manifestations of intoxication, as well as in positive changes in the structure of the intestine of the poultry during histological examination.

Defensive activity of Hesperidin against Ciprofloxacin induced hepatic injury in rabbits.

2019 ◽  
Vol 10 (03) ◽  
Author(s):  
Hawraa M. Murad ◽  
Tamadhur Hani Hussein ◽  
Audai Sulaiman Khudhair ◽  
Manal Muhi Murad ◽  
Jawad Kadhim Faris
Keyword(s):  
Body Weight ◽  
Bacterial Infections ◽  
Hepatoprotective Activity ◽  
The Body ◽  
Local Breed ◽  
Group 4 ◽  
Group 3 ◽  
Group 2 ◽  
Defensive Activity ◽  
Antioxidant Effects

This study was conducted to find out hepatoprotective activity of hesperidin (HES) 100mg/kg body weight (b.w.) against ciprofloxacin (CPX) 100 mg/kg induced hepatotoxicity in local breed rabbits .CPX is a broad spectrum antibiotic used for treatment of many bacterial infections. Twenty four male rabbits were divided into four groups ,group1: control, (1 ml/kg Saline orally) group 2: CPX (100 mg/kg orally) for (14) consecutive days , group 3: HES (100 mg//kg) orally for (14) consecutive days group 4: CPX (100 mg/kg orally) plus HES (100 mg//kg orally ) for (14) consecutive days. All the rabbits were killed on the (15) day of the experiment, and then the blood, and livers samples were taken. CPX induced hepatotoxicity was proved by a significant (p less than 0.01) reduction in the body weight ,and a significant (p less than 0.01) increased serum aspartate transaminase (AST), alanine transaminase (ALT) , Malonaldehyde enzyme (MAD) and histopathological changes. Protective hepatic toxicity effect and oxidative damage caused by CPX significantly (p less than 0.01) increasing in body weight and significantly (p less than 0.01) decreasing AST , ALT, MAD and improving tissue morphology in HES (100 mg//kg) . These results assure that HES (100 mg//kg) antioxidant effects can protect CPX-induced hepatotoxicity in rabbits.

Efficacy and safety of drospirenone-containing microdosage combined oral contraceptive use with starting contraception

GYNECOLOGY ◽  
2018 ◽  
Vol 20 (2) ◽  
pp. 9-13
Author(s):  
A R Khachaturian ◽  
E V Misharina ◽  
M I Yarmolinskaya
Keyword(s):  
Blood Pressure ◽  
Body Weight ◽  
Oral Contraceptive ◽  
Waist Circumference ◽  
Young Women ◽  
Iron Metabolism ◽  
Serum Iron ◽  
The Body ◽  
Menstrual Bleeding ◽  
Combined Oral Contraceptive

Androgen-dependent dermopathy, as well as premenstrual syndrome of varying severity in young women, can cause emotional depression, difficulties in social adaptation and even depressive disorders. The aim of the study was to study the safety and efficacy of using a combined oral contraceptive (COC) Dimia® containing 20 μg ethinyl estradiol and 3 mg drospirenone in young women, as well as its therapeutic effects in androgen-dependent dermopathy. Materials and methods. The study included 57 young women aged 23.1±2.2 years with signs of androgen-dependent dermopathy. The evaluation of the change in the character of menstrual bleeding, the anthropometric parameters (body weight, waist circumference and hips), the therapeutic effect of the drug on the symptoms of androgen-dependent dermopathy, as well as the dynamics of arterial pressure, hemoglobin level, serum iron have been studied. The psycho-emotional state was assessed using the SAN questionnaire (well-being-activity-mood). Results. During 6 months of observation, there was no significant change in the body mass index, waist circumference, and hips, and the drug did not affect the blood pressure numbers. Against the background of taking the drug, there was an increase in the parameters of iron metabolism (hemoglobin content, serum iron). After 3 months of taking the contraceptive with drospirenone, the number of patients with a complaint about the abundance of menstruation decreased more than twofold (from 22.8 to 10.5%), and after 6 months of taking the drug no patient noted the profuse nature of menstruation. Before the start of taking COC with drospirenone, 57.9% of women reported painful menstrual bleeding. Against the background of taking the contraceptive within 3 months, this complaint was stopped in all patients. Sufficient efficacy of treatment of androgen dependent dermopathy in young women with the help of a microdosed drospirenone-containing combined oral contraceptive is estimated from the dermatological acne index. The analysis of the SAN questionnaire made it possible to reveal the improvement in the psychoemotional state of patients on the background of taking the drug. The conclusion. The results obtained proved the effectiveness and safety of the microclinized COC Dimia®. The drug has no significant effect on body weight, blood pressure, provides reliable control of the cycle and a decrease in menstrual bleeding, which results in stabilization of iron metabolism in the body. Dimia® is effective in the treatment of androgen-dependent dermopathy and can be recommended to young women for starting contraception.

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