Magnetic Remanence in the Western Atlantic Spiny Lobster, Panulirus Argus

1984 ◽  
Vol 113 (1) ◽  
pp. 29-41 ◽  
Author(s):  
KENNETH J. LOHMANN

The magnetic characteristics of 15 western Atlantic spiny lobsters (Panulirus argus) were analysed with a superconducting cryogenic magnetometer. Each specimen possessed a significant natural remanent magnetization (NRM) and isothermal remanent magnetization (IRM), indicating that ferromagnetic material is present. Analyses of the distribution of total remanence and mass-specific remanence indicate that magnetic material is concentrated in the cephalothorax, particularly in tissue associated with the fused thoracic ganglia. Mass-specific remanence and the total quantity of magnetic material in the cephalothorax and abdomen both increase as functions of carapace length. The NRM is significantly orientated in at least four regions of the body. The NRM of the left half of the posterior cephalothorax is directed posteriorly, while that of the right half is orientated anteriorly. In addition, the NRM of the middle cephalothorax is orientated toward the right side of the animal; the NRM of the telson-uropods region is directed toward the left. The functional significance of these regions of orientated remanence is not known, but such a pattern could result from the ordered alignment of permanently magnetic particles comprising a magnetoreceptor system.

1999 ◽  
Vol 202 (22) ◽  
pp. 3155-3160 ◽  
Author(s):  
J. Brassart ◽  
J.L. Kirschvink ◽  
J.B. Phillips ◽  
S.C. Borland

Behavioral results obtained from the eastern red-spotted newt (Notophthalmus viridescens) led to the suggestion of a hybrid homing system involving inputs from both a light-dependent and a non-light-dependent mechanism. To evaluate the possible role of a receptor based on biogenic magnetite in this animal, we performed magnetometry experiments on a set of newts previously used in behavioral assays. The natural remanent magnetization (NRM) carried by these newts was strong enough to be measured easily using a direct-current-biased superconducting quantum interference device functioning as a moment magnetometer. Isothermal remanent magnetizations were two orders of magnitude higher than the NRM, suggesting that ferromagnetic material consistent with magnetite is present in the body of the newt. The NRM has no preferential orientation among the animals when analyzed relative to their body axis, and the demagnetization data show that, overall, the magnetic material grains are not aligned parallel to each other within each newt. Although the precise localization of the particles was not possible, the data indicate that magnetite is not clustered in a limited area. A quantity of single-domain magnetic material is present which would be adequate for use in either a magnetic intensity or direction receptor. Our data, when combined with the functional properties of homing, suggest a link between this behavioral response and the presence of ferromagnetic material, raising the possibility that magnetite is involved at least in the map component of homing of the eastern red-spotted newt.


1999 ◽  
Vol 202 (19) ◽  
pp. 2687-2692
Author(s):  
D. Acosta-Avalos ◽  
E. Wajnberg ◽  
P.S. Oliveira ◽  
I. Leal ◽  
M. Farina ◽  
...  

We report on the presence of magnetic iron oxides in the migratory ant Pachycondyla marginata. Magnetic particles were extracted from different parts of the ant (head, thorax and abdomen) using magnetic precipitation methods. Electron spectroscopic images for iron and oxygen were obtained from the extracted particles, and, by using the corresponding electron micrographs, histograms of size distribution were constructed. Selected area diffraction patterns were also obtained from the particles, and analysis of these showed the presence of a mixture of different iron oxides, including the magnetic oxides, magnetite and maghemite. The size distribution of the particles in the abdomen is different from that in the thorax and the head. In accordance with the hypothesis of magnetic orientation based on the presence of magnetic material within the body, two regions of the ant, the head and the abdomen, could be implicated in the detection of the geomagnetic field.


2020 ◽  
Vol 40 (6) ◽  
pp. 933-942 ◽  
Author(s):  
Nicole A M Atherley ◽  
Michelle M Dennis ◽  
Mark A Freeman

Abstract The Caribbean spiny lobster, Panulirus argus (Latreille, 1804), is an important resource in the Western Atlantic Ocean, Caribbean Sea, and Gulf of Mexico. A nemertean egg predator of P. argus, Carcinonemertes conanobrieniSimpson, Ambrosio & Baeza, 2017, was recorded in Florida in 2017 and Colombia in 2018. This study sought to investigate the presence of C. conanobrieni in P. argus in Saint Kitts and Nevis, eastern Caribbean Sea. Nemerteans were observed in the brood masses of P. argus. Molecular techniques confirmed its presence in the P. argus population on Saint Kitts. Egg, juvenile, and adult stages of C. conanobrieni and of an undescribed Carcinonemertes sp. were found in the brood masses of 27 of 31 (87%) ovigerous P. argus. Differences in the shape of the nemertean egg masses (string versus spherical arrangement) were confirmed as two distinct species of Carcinonemertes Coe, 1902 using molecular analyses. The juvenile stage of the undescribed Carcinonemertes sp. was detected in the gills of 72 of 320 (23%) of the P. argus individuals from Saint Kitts. The prevalence of branchial nemertean infestation was not significantly different among male and female P. argus. Female lobsters with ovaries in early stages of gonadal maturation were more likely to have branchial nemerteans relative to those with ovaries in late stages of maturation, suggestive of nemertean migration from gills to egg mass once the host oviposits. This is the first report of C. conanobrieni in the Caribbean spiny lobster from the eastern Caribbean, which is approximately 1,300 miles from Florida and 1,000 miles from Colombia. This is also the first report of an undescribed nemertean worm in P. argus. The high prevalence of Carcinonemertes spp. in P. argus raises concern for the extent to which these egg predators may be impacting P. argus in Saint Kitts, an important fishery on the island.


2020 ◽  
Vol 8 (1) ◽  
Author(s):  
S Clay Steell ◽  
Steven J Cooke ◽  
Erika J Eliason

Abstract Light pollution is a rapidly growing threat to biodiversity, with many unknown or poorly understood effects on species and ecosystems spanning terrestrial and aquatic environments. Relative to other taxa, the effects of artificial light at night on aquatic invertebrates are poorly understood, despite the abundance and integral significance of invertebrates to marine and freshwater ecosystems. We affixed heart rate and acceleration biologgers to adult Caribbean spiny lobster (Panulirus argus), an ecologically, culturally and economically significant species in the western Atlantic ocean, to test the effect of artificial light at night on this species’ physiology and behaviour relative to appropriate controls. The experiment was conducted in a simulated reef mesocosm in The Bahamas with incandescent lighting used to illuminate it at 1 lux, approximating light levels offshore of urban areas. In the conditions tested here, artificial light at night was found to have no effect on heart rate or locomotor activity in P. argus. We observed a dissociation between activity and heart rate at both short-term and long-term temporal scales. Lobsters were more active at night and nocturnal activity was higher in trials closer to new moon; however, heart rate did not vary with diel or lunar cycle. There was less than 8% difference between daytime and night time average heart rate despite the average percentage of time spent active almost tripling in nights versus days, to 19.5% from 7.2%, respectively. Our findings suggest P. argus may have some resilience to low levels of light pollution, which warrants further research on aspects of this species’ life history, performance and fitness in the face of this potential anthropogenic disturbance.


Author(s):  
Anne Phillips

No one wants to be treated like an object, regarded as an item of property, or put up for sale. Yet many people frame personal autonomy in terms of self-ownership, representing themselves as property owners with the right to do as they wish with their bodies. Others do not use the language of property, but are similarly insistent on the rights of free individuals to decide for themselves whether to engage in commercial transactions for sex, reproduction, or organ sales. Drawing on analyses of rape, surrogacy, and markets in human organs, this book challenges notions of freedom based on ownership of our bodies and argues against the normalization of markets in bodily services and parts. The book explores the risks associated with metaphors of property and the reasons why the commodification of the body remains problematic. The book asks what is wrong with thinking of oneself as the owner of one's body? What is wrong with making our bodies available for rent or sale? What, if anything, is the difference between markets in sex, reproduction, or human body parts, and the other markets we commonly applaud? The book contends that body markets occupy the outer edges of a continuum that is, in some way, a feature of all labor markets. But it also emphasizes that we all have bodies, and considers the implications of this otherwise banal fact for equality. Bodies remind us of shared vulnerability, alerting us to the common experience of living as embodied beings in the same world. Examining the complex issue of body exceptionalism, the book demonstrates that treating the body as property makes human equality harder to comprehend.


2013 ◽  
Vol 7 (1) ◽  
pp. 7
Author(s):  
Doni Budiono

The  authority  of justice in Indonesia  is executed by  the Supreme Courts and  the  justice  boards/body under the Supreme Courts, including  the general  justice, religious affairs justice, military justice,  state administration  justice,  and  the Constitution Court. According to  certainty in  the Act of  Tax Court, Article1, clause  (5),  tax  dispute   refers to the legal dispute arising in the  taxation  affairs between the  tax payer or the  body  responsible for the  tax with   the government   executives  ( Directorate General of Tax) as the consequence of   the issue of  the decree for the  appeal  to the Tax  Court in accordance with the  tax Act, including the  charge  against the  execution of collection   in accordance with the  Act of Tax Collection by force. The  formation of Tax Court is  designed by  the Executives, in this case, the  Department of Finance, specifically  the Directorate   General  of Tax  which has the right to issue  law  more technical about  tax accord to Article 14,  letter A,  President Decree  no. 44  year 1974,  concerning the  basic  organization of the Department.  Based on  it,  it  is clear that  in addition to execute the government  rules and policy,  this body  has to execute judicial   rules and policy. This is against the  principles of  Judicative  Power/Authority in Indonesia,  which   clearly states that this body  should be under the Supreme Court.   Therefore. It is suggested that   the Act  No UU no.14 Year 2012 concerning  Tax Court   be revised  in accordance with the system of  Power Division  of Justice  as  stated in 45 Constitutions.


2020 ◽  
Vol 11 (SPL1) ◽  
pp. 1477-1481
Author(s):  
Ishwari Gaikwad ◽  
Priyanka Shelotkar

The current world situation is both frightening and alarming due to the massive disruption caused by the Covid-19 pandemic. The next few days are censorious as we need to be very precautious in our daily regimen as well as dietary habits. Ayurveda offers knowledge about food based on certain reasoning. Indecent food custom is the chief cause for the rising development of health disorders in the current era. In classical texts of Ayurveda, the concept of diet explained well, ranging from their natural sources, properties and specific utility in pathological as well as physiological manner. In this work, the review of the relevant literature of Ahara (Diet) was carried out from Charak Samhita and other texts, newspapers, articles, web page related to the same.  Every human being is unique with respect to his Prakriti (Physical and mental temperament), Agni (Digestive capacity), Koshtha  (Nature of bowel) etc. For that reason, the specificity of the individual should be kept in mind. Ahara, when consumed in the appropriate amount at the right moment following all Niyamas (Guidelines) given in Ayurveda texts, gives immunity and keeps the body in a healthy state during pandemics such as Covid-19. Ultimately, this will help the human body to maintain its strength for life. This article reviews the concept of diet viz. combination of foods, their quantity and quality, methods of preparation and processing, which are to be followed during pandemics and are essential in maintenance and endorsement of health and preclusion of diseases.


2020 ◽  
Vol 11 (SPL1) ◽  
pp. 832-838
Author(s):  
Roshna Sukheoji Bhutada ◽  
Renu Rathi ◽  
Devyani Dasar

WHO declared Covid 19 /SARS -COV-2 as a global pandemic.Till date, there is no medicine for COVID-19. If the Infection arises in the body then the defence mechanism activated against infection. A recent study suggests that temporarily augmenting the body's immune system in the early stages of COVID-19 can help patient to avoid severe symptoms as it is rightly said prevention is better than cure. Ayurveda approaches to develop physiological reactions to facilitate immunity. Planning of diet is most important to boost immunity.As per many researches to provide supplementary food which contains Zinc, Vitamin C,Vitamin D and immunity boosting foodsuch as citrus natural products, custard apple, apple, papaya is among the Fruits. Vegetables include broccoli, onion, garlic and green leafy vegetables. Nuts, ginger, turmeric, pepper, egg yolk, shellfish, mushroom. The need of the hour is a quick boost to immune system to keep it fit, fighting. One should get the right amount of nutrients from the diet, supplementation regimen to boost immune system.In this review, there are few common supplements and super food studies have been included. It might be a torch bearer as sample menu and their alternatives are given for a normal adult. Needy may change contemplated according to age, sex, body mass index and daily physical activities.


2019 ◽  
Vol 85 (1(I)) ◽  
pp. 35-44
Author(s):  
S. G. Sandomirski

The main magnetic parameters sensitive to the structure of steels are the parameters of their saturation loop of magnetic hysteresis: the coercive force Hcs and remanent magnetization Mrs. The saturation magnetization or saturation intensity Mr is most sensitive to the phase composition of steels. The variety of steel grades and modes of technological treatment (e.g., heat treatment, mechanical load) determined the use of magnetic structurescopy and magnetic characteristics — the coercive force Hc, remanent magnetization Mr , and specific hysteresis losses Wh on the subloops of the magnetic hysteresis of steels — as control parameters in diagnostics of the stressed and structural states of steel structures and pipelines. It has been shown that changes in Hc, Mr , and Wh are more sensitive to structural stresses and structures of steels than the parameters of the saturation hysteresis loop of magnetic hysteresis (Hcs, Mrs, and Mrs). The formulas for calculating Hc, Mr and Wh are presented to be used for estimation of changes in the parameters upon heat treatment of steels. Features of the structural sensitivity of the subloop characteristics and expediency of their use for magnetic structural and phase analyzes are determined. Thus, the range of changes in Ìr attributed to the structural changes in steels upon gradual Hm decrease is many times wider compared to the range of possible changes in Mrs under the same conditions. Conditions (relations between the magnetic parameters) and recommendations regarding the choice of the field strength Hm are given which provide the justified use of Hc, Mr and Wh parameters in magnetic structurescopy


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