1000 resultados para Defensive systems
Resumo:
Universidade Estadual de Campinas . Faculdade de Educação Física
Resumo:
Universidade Estadual de Campinas . Faculdade de Educação Física
Resumo:
Universidade Estadual de Campinas . Faculdade de Educação Física
Resumo:
In sport there is a great need to obtain as much information as possible about the factors which affect the dynamics of play. This study uses sequential analysis and temporal patterns (T-patterns)to examine the evolution of defence (against an equal number of attackers)as used by the Spanish handball team at the Beijing 2008 Olympic Games. The aim is to help handball coaches (during their training and gathering of professional experience)to understand the importance of the structure of defensive systems. This can be achieved through observational processes that reveal the evolution and adaptation of these defensive systems according to different variables: the match score, the response of the opposing team and progress through the tournament.
Resumo:
Sosialistisen vallankumouksen jälkeen Neuvosto-Venäjän oli monien muiden kysymysten ohella ratkaistava sosialismin saavutusten puolustaminen. Aluksi ratkaisuksi suunniteltiin vapaaehtoisuuteen perustuvaa punakaartia, mutta riittävän miesvahvuuden turvaamiseksi päädyttiin yleiseen asevelvollisuuteen. Pian Venäjän sisällissodan jälkeen sotataidon suunta painottui enemmän vanhan armeijan asiantuntijoiden näkemysten kuin vallankumoussankarien kokemusten mukaiseksi, vaikka Frunzen puna-armeijalle kirjoittama doktriini perustui luokkataisteluun ja korosti sisällissodassa hyväksi koettua operatiivista liikkuvuutta. Neuvostoliiton ja Venäjän sotataidon perustana on Pietari I:n aloittama länsimainen suuntaus, jota kuitenkin täydentävät vahvat kansalliset piirteet. Venäläisen sotataidon henkisenä isänä voidaan hyvällä syyllä pitää Aleksandr Suvorovia, jonka opetukset näkyvät tekstilainausten lisäksi myös periaatteissa ja sotilaskasvatuksessa. Napoleonin sotien jälkeen perustettu Keisarillinen yleisesikunta-akatemia loi Venäjälle sotatieteellisen tutkimuksen ja opetuksen. Sotatieteen mahdollisuuksia ei 1800-luvun Venäjällä osattu täysin hyödyntää. Aseistuksen kasvavan tehon merkitystä vähättelevä asenne johti sotataidon taantumisen ja katastrofiin Venäjän–Japanin sodassa. Sen kokemuksia analysoidessaan Aleksandr Neznamov kehitti edelleen saksalaista operaation käsitettä ja loi perustan Neuvostoliitossa 1920-luvulla kehitetylle operaatiotaidolle. Neuvostoliittolaisen sotataidon päämääränä oli kehittää taktinen ja operatiivinen ratkaisu aseistuksen tehon kasvun aikaansaamaan puolustuksen ylivoimaisuuteen. Ratkaisussa hyödynnettiin brittien kokemuksia ja tutkimusta. Neuvostoliittolainen taktiikka ja operaatiotaito eivät kuitenkaan olleet brittiläisen mekanisoidun sodankäynnin tai saksalaisen salamasodan itäinen kopioita vaan itsenäisiin ratkaisuihin pohjautuvia. Syvän taistelun ja operaation teoriaa kokeiltiin harjoituksissa, ja sitä kehitettiin Stalinin vuoden 1937 puhdistuksiin saakka. Toisen maailmansodan taisteluissa puna-armeija sovelsi alkuvaiheen katastrofin jälkeen syvän taistelun ja syvän operaation oppeja. Komentajien ja joukkojen taito ei riittänyt teorian vaatimusten mukaiseen toimintaan, siksi syväksi aiotusta taistelusta tuli ajoittain ainoastaan tiheää. Suuren isänmaallisen sodan kokemusten perusteella neuvostoliittolainen sotatiede kehitti yleisjoukkojen taistelun periaatteet, jotka ovat säilyneet muuttumattomina nykypäivään saakka. Kylmän sodan aikakaudella ydin- ja tavanomaisen aseistuksen merkitys sodan ja taistelun kuvassa vaihteli. Lännen sotataidon ja aseteknologian kehitys pakotti Neuvostoliiton siirtymään 1980-luvulla sotilaallisessa ajattelussaan hyökkäyksestä puolustukseen. Neuvostoliiton hajoamisen jälkeen Venäjän sotilaallisen turvallisuuden takaajana on ydinaseistus. Yhdysvaltain tavanomainen ilma-avaruushyökkäyskyky vaatii Venäjää kehittämään torjuntajärjestelmiä. Tavanomaisten joukkojen rakentamisessa Venäjä seuraa tarkasti läntisen sotataidon kehittymistä, mutta pitäytyy omaperäisiin ratkaisuihin, joiden kehittämisessä sen vahvalla sotatieteellisellä järjestelmällä ja dialektisen materialismin metodilla on edelleen olennaisen tärkeä merkitys.
Resumo:
Este estudio es una síntesis de las últimas aportaciones acerca de las vías en al-Andalus (ss. VIII-XV), cuya estructura inicial es herencia de la época romana. Dadas las limitaciones que imponen los escasos datos que hallamos en las fuentes árabes y los pocos restos camineros conocidos, se hace necesario emplear una nueva metodología de investigación: Se aborda el objeto como un estudio global, no sólo de los caminos, sino de todos los elementos interrelacionados con ellos, denominados como "espacios viales". Luego se presenta la indisoluble relación de los "espacios viales" con los castillos y torres ("espacios de control y defensa") en al-Andalus, como los vigilantes de los caminos, y se enuncia la toponimia árabe relacionada tanto con los "espacios viales" como con los "espacios de control y defensa". Finalmente, se recogen los datos que las diversas crónicas árabes nos proporcionan acerca de la política viaria en al-Andalus a lo largo del tiempo, así como sobre quién era el responsable de velar por el buen estado de los tramos viales.
Resumo:
This portfolio thesis describes work undertaken by the author under the Engineering Doctorate program of the Institute for System Level Integration. It was carried out in conjunction with the sponsor company Teledyne Defence Limited. A radar warning receiver is a device used to detect and identify the emissions of radars. They were originally developed during the Second World War and are found today on a variety of military platforms as part of the platform’s defensive systems. Teledyne Defence has designed and built components and electronic subsystems for the defence industry since the 1970s. This thesis documents part of the work carried out to create Phobos, Teledyne Defence’s first complete radar warning receiver. Phobos was designed to be the first low cost radar warning receiver. This was made possible by the reuse of existing Teledyne Defence products, commercial off the shelf hardware and advanced UK government algorithms. The challenges of this integration are described and discussed, with detail given of the software architecture and the development of the embedded application. Performance of the embedded system as a whole is described and qualified within the context of a low cost system.
Resumo:
Descriptors: cardiovascular patterns, emotion, affective pictures In this study we assessed blood pressure (BP), heart rate (HR), stroke volume (SV), cardiac output (CO), and total peripheral resistance (TPR) in response to 13 picture series in 18 men and 19 women in order to investigate their hemodynamic responses associated with activation of the appetitive and defensive motivational systems underlying emotional experience. Skin conductance level (SCL) was also recorded. BP and SV increased with increasing self-rated arousal both for appetitive and defensive activation, whereas HR decelerated more in response to negative than positive and neutral pictures. TPR showed a general increase from baseline to picture processing but was unrelated to self-rated valence and arousal. These findings suggest that affective modulation of the cardiovascular response to affective pictures is primarily myocardial. The observed response pattern is consistent with a configuration of cardiac sympathetic-parasympathetic coactivation. The relationships between self-reported arousal, BP and SV were mainly exhibited by men suggesting that increases in the sympathetic inotropic effect to the heart with increasing self-rated arousal might be larger in men than in women. In contrast, SCL covaried positively with self-rated arousal both in men and women. This suggests that sex differences in the affective modulation of the responses to pictures may be restricted to specific cardiovascular parameters and support the contention that the sympathetic nervous system does not discharge as a whole.
Resumo:
In this study we assessed blood pressure (BP), heart rate (HR), stroke volume (SV), cardiac output (CO), and total peripheral resistance (TPR) in response to 13 picture series in 37 participants in order to investigate their hemodynamic response associated with activation of the appetitive and defensive motivational systems underlying emotional experience. BP and SV, but not TPR, increased with increasing self-rated arousal, whereas HR decelerated more in response to negative than positive and neutral pictures. These findings suggest that modulation of the cardiovascular response to pictures is primarily myocardial. The observed response pattern is consistent with a configuration of cardiac sympathetic-parasympathetic coactivation. The relationships between self-rated arousal, BP, and SV were mainly exhibited by men, suggesting that increases in the sympathetic inotropic effect to the heart with self-rated arousal may be larger in men than in women.
Resumo:
Sunlight is part of our everyday life and most people accept it as beneficial to our health. With the advance of our knowledge in cutaneous photochemistry, photobiology and photomedicine over the past four decades, the terrestrial solar radiation has become a concern of dermatologists and is considered to be a major damaging environmental factor for our skin. Most photobiological effects (e.g., sunburn, suntanning, local and systemic immunosuppression, photoaging or dermatoheliosis, skin cancer and precancer, etc.) are attributed to ultraviolet radiation (UVR) and more particularly to UVB radiation (290-320 nm). UVA radiation (320-400 nm) also plays an important role in the induction of erythema by the photosensitized generation of reactive oxygen species (singlet oxygen (1O2), superoxide (O2.-) and hydroxyl radicals (.OH)) that damage DNA and cellular membranes, and promote carcinogenesis and the changes associated with photoaging. Therefore, research efforts have been directed at a better photochemical and photobiological understanding of the so-called sunburn reaction, actinic or solar erythema. To survive the insults of actinic damage, the skin appears to have different intrinsic defensive mechanisms, among which antioxidants (enzymatic and non-enzymatic systems) play a pivotal role. In this paper, we will review the basic aspects of the action of UVR on the skin: a) photochemical reactions resulting from photon absorption by endogenous chromophores; b) the lipid peroxidation phenomenon, and c) intrinsic defensive cutaneous mechanisms (antioxidant systems). The last section will cover the inflammatory response including mediator release after cutaneous UVR exposure and adhesion molecule expression
Resumo:
This paper presents an up-to-date review of the evidence indicating that atypical neurotransmitters such as nitric oxide (NO) and endocannabinoids (eCBs) play an important role in the regulation of aversive responses in the periaqueductal gray (PAG). Among the results supporting this role, several studies have shown that inhibitors of neuronal NO synthase or cannabinoid receptor type 1 (CB1) receptor agonists cause clear anxiolytic responses when injected into this region. The nitrergic and eCB systems can regulate the activity of classical neurotransmitters such as glutamate and γ-aminobutyric acid (GABA) that control PAG activity. We propose that they exert a ‘fine-tuning’ regulatory control of defensive responses in this area. This control, however, is probably complex, which may explain the usually bell-shaped dose-response curves observed with drugs that act on NO- or CB1-mediated neurotransmission. Even if the mechanisms responsible for this complex interaction are still poorly understood, they are beginning to be recognized. For example, activation of transient receptor potential vanilloid type-1 channel (TRPV1) receptors by anandamide seems to counteract the anxiolytic effects induced by CB1 receptor activation caused by this compound. Further studies, however, are needed to identify other mechanisms responsible for this fine-tuning effect.
Resumo:
In this study we provide a comprehensive analysis of the hypothalamic activation pattern during exposure to a live predator or an environment previously associated with a predator. Our results support the view that hypothalamic processing of the actual and the contextual predatory threats share the same circuit, in which the dorsal premammillary nucleus (PMd) plays a pivotal role in amplifying this processing. To further understand the role of the PMd in the circuit organizing antipredatory defensive behaviors, we studied rats with cytotoxic PMd lesions during cat exposure and examined the pattern of behavioral responses as well as how PMd lesions affect the neuronal activation of the systems engaged in predator detection, in contextual memory formation and in defensive behavioral responses. Next, we investigated how pharmacological blockade of the PMd interferes with the conditioned behavioral responses to a context previously associated with a predator, and how this blockade affects the activation pattern of periaqueductal gray (PAG) sites likely to organize the conditioned behavioral responses to the predatory context. Behavioral observations indicate that the PMd interferes with both unconditioned and conditioned antipredatory defensive behavior. Moreover, we have shown that the PMd influences the activation of its major projecting targets, i.e. the ventral part of the anteromedial thalamic nucleus which is likely to influence mnemonic processing, and PAG sites involved in the expression of antipredatory unconditioned and conditioned behavioral responses. Of particular relevance, this work provides evidence to elucidate the basic organization of the neural circuits integrating unconditioned and contextual conditioned responses to predatory threats.
Resumo:
The aggressive behavior of ants that protect plants from herbivores in exchange for rewards such as shelter or food is thought to be an important form of biotic defense against herbivory, particularly in tropical systems. To date, however, no one has compared the defensive responses of different ant taxa associated with the same plant species, and attempted to relate these differences to longer-term efficacy of ant defense. We used experimental cues associated with herbivory-physical damage and extracts of chemical volatiles from leaf tissue-to compare the aggressive responses of two ant species obligately associated with the Amazonian myrmecophyte Tococa bullifera (Melastomataceae). We also conducted a colony removal experiment to quantify the level of resistance from herbivores provided to plants by each ant species. Our experiments demonstrate that some cues eliciting a strong response from one ant species elicited no response by the other. For cues that do elicit responses, the magnitude of these responses can vary interspecifically. These patterns were consistent with the level of resistance provided from herbivores to plants. The colony removal experiment showed that both ant species defend plants from herbivores: however, herbivory was higher on plants colonized by the less aggressive ant species. Our results add to the growing body of literature indicating defensive ant responses are stimulated by cues associated with herbivory. However, they also suggest the local and regional variation in the composition of potential partner taxa could influence the ecology and evolution of defensive mutualisms in ways that have previously remained unexplored.
Resumo:
The midbrain dorsal periaqueductal gray (DPAG) is part of the brain defensive system involved in active defense reactions to threatening stimuli. Corticotrophin releasing factor (CRF) is a peptidergic neurotransmitter that has been strongly implicated in the control of both behavioral and endocrine responses to threat and stress. We investigated the effect of the nonspecific CRF receptor agonist, ovine CRF (oCRF), injected into the DPAG of mice, in two predator-stress situations, the mouse defense test battery (MDTB), and the rat exposure test (RET). In the MDTB, oCRF weakly modified defensive behaviors in mice confronted by the predator (rat); e.g. it increased avoidance distance when the rat was approached and escape attempts (jump escapes) in forced contact. In the RET, drug infusion enhanced duration in the chamber while reduced tunnel and surface time, and reduced contact with the screen which divides the subject and the predator. oCRF also reduced both frequency and duration of risk assessment (stretch attend posture: SAP) in the tunnel and tended to increase freezing. These findings suggest that patterns of defensiveness in response to low intensity threat (RET) are more sensitive to intra-DPAG oCRF than those triggered by high intensity threats (MDTB). Our data indicate that CRF systems may be functionally involved in unconditioned defenses to a predator, consonant with a role for DPAG CRF systems in the regulation of emotionality. (c) 2006 Elsevier B.V. All rights reserved.
Resumo:
Anurans may be brightly colored or completely cryptic. Generally, in the former situation, we are dealing with aposematism, and the latter is an example of camouflage. However, these are only simple views of what such colorations really mean and which defensive strategy is implied. For instance, a brightly colored frog may be part of a mimicry ring, which could be either Batesian, Müllerian, or Browerian. These are only examples of the diversity of color-usage systems as defensive strategies. Unfortunately, reports on the use of colors as defensive mechanisms are widespread in the available literature, and the possible functions are rarely mentioned. Therefore, we reviewed the literature and added new data to this subject. Then, we the use of colors (as defensive mechanism) into categories. Mimicry was divided into the subcategories camouflage, homotypy, and nondeceitful homotypy, and these groups were also subcategorized. Dissuasive coloration was divided into behavioral display of colors, polymorphism, and polyphenism. Aposematism was treated apart, but aposematic colorations may be present in other defensive strategies. Finally, we propose functions and forms of evolution for some color systems in post-metamorphic anurans and hope that this review can be the basis for future research, even on other animal groups. © 2009 L. F. Toledo and C. F. B. Haddad.