Statistical interaction modeling of bovine herd behaviors

While there has been interest in modeling the group behavior of herds or flocks, much of this work has focused on simulating their collective spatial motion patterns which have not accounted for individuality in the herd and instead assume a homogenized role for all members or sub-groups of the herd. Animal behavior experts have noted that domestic animals exhibit behaviors that are indicative of social hierarchy: leader/follower type behaviors are present as well as dominance and subordination, aggression and rank order, and specific social affiliations may also exist. Both wild and domestic cattle are social species, and group behaviors are likely to be influenced by the expression of specific social interactions. In this paper, Global Positioning System coordinate fixes gathered from a herd of beef cows tracked in open fields over several days at a time are utilized to learn a model that focuses on the interactions within the herd as well as its overall movement. Using these data in this way explores the validity of existing group behavior models against actual herding behaviors. Domain knowledge, location geography and human observations, are utilized to explain the causes of these deviations from this idealized behavior

Rising top-income persistence in Australia: evidence from income tax data

We use a new Australian longitudinal income tax dataset, Alife, covering 1991–2017, to examine levels and trends in the persistence in top-income group membership, focussing on the top 1%. We summarize persistence in multiple ways, documenting levels and trends in rates of remaining in top-income groups; re-entry to the top; the income changes associated with top-income transitions; and we also compare top-income persistence rates for annual and ‘permanent’ incomes. Regardless of the perspective taken, top-income persistence increased markedly over the period, with most of the increase occurring in the mid-2000s and early 2010s. In the mid- to late2010s, Australian top-income persistence rates appear to have been near the top of the range of tax-data estimates for other countries. Using univariate breakdowns and multivariate regression, we show that the rise in top-income persistence in Australia was experienced by many population subgroups

Acidentes por serpentes Crotalus durisssus ssp em crianças em Campinas, São Paulo, Brasil

From January, 1984 to March, 1999, 31 children under 15 y old (ages 1-14 y, median 8 y) were admitted after being bitten by rattlesnakes (Crotalus durissus ssp). One patient was classified as "dry-bite", 3 as mild envenoming, 9 as moderate envenoming and 18 as severe envenoming. Most patients had neuromuscular manifestations, such as palpebral ptosis (27/31), myalgia (23/31) and weakness (20/31). Laboratory tests suggesting rhabdomyolysis included an increase in total blood creatine kinase (CK, 28/29) and lactate dehydrogenase (LDH, 25/25) levels and myoglobinuria (14/15). The main local signs and symptoms were slight edema (20/31) and erythema (19/31). Before antivenom (AV) administration, blood coagulation disorders were observed in 20/25 children that received AV only at our hospital (incoagulable blood in 17/25). AV early reactions were observed in 20 of these 25 cases (9/9 patients not pretreated and 11/16 patients pretreated with hydrocortisone and histamine H1 and H2 antagonists). There were no significant differences in the frequency of patients with AV early reactions between the groups that were and were not pretreated (Fisher's exact test, p = 0.12). Patients admitted less than and more than 6 h after the bite showed the same risk of developing severe envenoming (Fisher's exact test, p = 1). No children of the first group (< 6 h) showed severe complications whereas 3/6 children admitted more than 6 h post-bite developed acute renal failure. Patients bitten in the legs had a higher risk of developing severe envenoming (Fisher's exact test, p = 0.04). There was a significant association between both total CK and LDH blood enzyme levels and severity (p < 0.001 for CK and p < 0.001 for LDH; Mann-Whitney U test). No deaths were recorded.De janeiro de 1984 a março de 1999, 31 crianças com menos de 15 anos de idade (1 a 14 anos, mediana = 8 anos) foram admitidas após terem sido picadas por Crotalus durissus ssp. Uma criança não apresentou manifestações clínicas de envenenamento, enquanto 3 foram classificadas como acidente leve, 9 como moderado e 18 como grave. A maioria das crianças apresentou envolvimento neuromuscular, tais como ptose palpebral (27/31), mialgia (23/31) e fraqueza (20/31). Alterações laboratoriais sugerindo rabdomiólise também foram observadas, como aumento das enzimas séricas CK (28/29) e LDH (25/25) e mioglobinúria (14/15). As principais manifestações locais observadas foram edema discreto (20/31) e eritema (19/31). Alterações da coagulação, antes da administração da soroterapia antiveneno (SAV), foram observadas em 20 das 25 crianças que receberam a SAV exclusivamente em nosso hospital (sangue incoagulável em 17/25). Reações precoces à SAV foram observadas em 20 destes 25 casos, em todos os pacientes não pré-tratados (N = 9) e em 11 dentre os 16 pré-tratados com antagonistas H1 e H2 da histamina e hidrocortisona. Não foram constatadas diferenças estatísticas significativas comparando-se a freqüência de reações precoces à SAV entre os grupos que receberam ou não o pré-tratamento (teste exato de Fisher, p = 0,12). Pacientes atendidos com menos ou mais de 6 horas após o acidente apresentaram o mesmo risco quanto a evolução para casos graves (teste exato de Fisher, p = 1), não se observando complicações graves no 1º grupo (< 6 h), enquanto 3/6 admitidos mais de 6 horas após a picada evoluíram com insuficiência renal aguda. Pacientes picados na perna apresentaram um maior risco de desenvolver acidentes graves (teste exato de Fisher, p = 0,04). Houve uma associação significativa entre os níveis séricos das enzimas CK e LDH total e gravidade (teste U de Mann-Whitney, CK, p < 0,001; LDH, p < 0,001). Nenhum óbito foi registrado

Acidentes por serpentes do gênero Bothrops em crianças em Campinas, São Paulo, Brasil

From January, 1984 to March, 1999, 73 children under 15 y old (ages 1-14 y, median 9 y) were admitted after being bitten by snakes of the genus Bothrops. Twenty-six percent of the children were classified as mild envenoming, 50.7% as moderate envenoming and 20.6% as severe envenoming. Two patients (2.7%) showed no signs of envenoming. Most of the patients presented local manifestations, mainly edema (94.5%), pain (94.5%) ecchymosis (73.9%) and blisters (11%). Local and/or systemic bleeding was observed in 28.8% of the patients. Before antivenom (AV) administration, blood coagulation disorders were observed in 60.7% (incoagulable blood in 39.3%) of the 56 children that received AV only in our hospital. AV early reactions, most of which were considered mild, were observed in 44.6% of these cases (in 15/30 patients not pretreated and in 10/26 patients pretreated with hydrocortisone and histamine H1 and H2 antagonists). The main clinical complications observed were local infection (15.1%), compartment syndrome (4.1%), gangrene (1.4%) and acute renal failure (1.4%). No deaths were recorded. There were no significant differences with regard to severity of envenoming versus the frequency of blood coagulation disorders among the three categories of envenoming (p = 0.75) or in the frequency of patients with AV early reactions between the groups that were and were not pretreated (p = 0.55). The frequency of local infection was significantly greater in severe cases (p < 0.001). Patients admitted more than 6 h after the bite had a higher risk of developing severe envenoming (p = 0.04).De janeiro de 1984 a março de 1999, 73 crianças com menos de 15 anos de idade (1 a 14 anos, mediana = 9 anos) foram admitidas após terem sido picadas por serpentes do gênero Bothrops. 26,0% das crianças foram classificadas como acidente leve, 50,7% como moderado e 20,6% como grave. Dois pacientes (2,7%) não apresentaram sinais de envenenamento. A maioria dos pacientes apresentou manifestações locais, principalmente edema (94,5%), dor (94,5%), equimoses (73,9%) e bolhas (11,0%). Sangramento local e/ou sistêmico foi constatado em 28,8% das crianças. Alterações da coagulação, antes da administração da soroterapia antiveneno (SAV), foram observadas em 60,7% (sangue incoagulável em 39,3%) das 56 crianças que receberam a SAV exclusivamente em nosso hospital. Reações precoces à SAV foram observadas em 44,6% destes 56 casos, sendo 15 em 30 pacientes não pré-tratados e 10 dentre 26 pré-tratados com antagonistas H1 e H2 da histamina e hidrocortisona, a maioria das quais foi considerada leve. As principais complicações observadas foram a infecção local (15,1%), a síndrome de compartimento (4,1%), gangrena (1,4%) e insuficiência renal aguda (1,4%). Nenhum óbito foi registrado. Não foram constatadas diferenças estatísticas significativas comparando-se a freqüência de distúrbios da coagulação de acordo com a gravidade (p = 0,75), bem como na freqüência de reações precoces à SAV entre os grupos que receberam ou não o pré-tratamento (p = 0,55). A freqüência de infecção local foi significativamente maior nos casos graves (p < 0,001). Pacientes atendidos mais de 6 horas após o acidente apresentaram um maior risco quanto à evolução para casos graves (p = 0,04)

Scorpion venom increases acetylcholine release by prolonging the duration of somatic nerve action potentials

Scorpionism is frequently accompanied by a massive release of catecholamines and acetylcholine from peripheral nerves caused by neurotoxic peptides present in these venoms, which have high specificity and affinity for ion channels. Tityus bahiensis is the second most medically important scorpion species in Brazil but, despite this, its venom remains scarcely studied, especially with regard to its pharmacology on the peripheral (somatic and autonomic) nervous system. Here, we evaluated the activity of T. bahiensis venom on somatic neurotransmission using myographic (chick and mouse neuromuscular preparations), electrophysiological (MEPP, EPP, resting membrane potentials, perineural waveforms, compound action potentials) and calcium imaging (on DRG neurons and muscle fibres) techniques. Our results show that the major toxic effects of T. bahiensis venom on neuromuscular function are presynaptically driven by the increase in evoked and spontaneous neurotransmitter release. Low venom concentrations prolong the axonal action potential, leading to a longer depolarization of the nerve terminals that enhances neurotransmitter release and facilitates nerve-evoked muscle contraction. The venom also stimulates the spontaneous release of neurotransmitters, probably through partial neuronal depolarization that allows calcium influx. Higher venom concentrations block the generation of action potentials and resulting muscle twitches. These effects of the venom were reversed by low concentrations of TTX, indicating voltage-gated sodium channels as the primary target of the venom toxins. These results suggest that the major neuromuscular toxicity of T. bahiensis venom is probably mediated mainly by α- and β-toxins interacting with presynaptic TTX-sensitive ion channels on both axons and nerve terminals

Neurotoxicity of Tityus bahiensis (brown scorpion) venom in sympathetic vas deferens preparations and neuronal cells

Systemic scorpion envenomation is characterized by massive neurotransmitter release from peripheral nerves mediated primarily by scorpion venoms neurotoxins. Tityus bahiensis is one of the medically most important species in Brazil, but its venom pharmacology, especially regarding to peripheral nervous system, is poorly understood. Here, we evaluated the T. bahiensis venom activity on autonomic (sympathetic) neurotransmission by using a variety of approaches, including vas deferens twitch-tension recordings, electrophysiological measurements (resting membrane potentials, spontaneous excitatory junctional potentials and whole-cell patch-clamp), calcium imaging and histomorphological analysis. Low concentrations of venom (≤ 3 μg/mL) facilitated the electrically stimulated vas deferens contractions without affecting postsynaptic receptors or damaging the smooth muscle cells; transient TTX-sensitive sustained contractions and resting membrane depolarization were mediated mainly by massive spontaneous ATP release. High venom concentrations (≥ 10 μg/mL) blocked the muscle contractions and induced membrane depolarization. In neuronal cells (ND7-23wt), the venom increased the peak sodium current, modified the current-voltage relationship by left-shifting the Nav channel activation curve, thereby facilitating the opening of these channels. The venom also caused a time-dependent increase in neuronal calcium influx. These results indicate that the sympathetic hyperstimulation observed in systemic envenomation is presynaptically driven, probably through the interaction of α- and β-toxins with neuronal sodium channels

Neurotoxicity of Micrurus lemniscatus lemniscatus (South American coralsnake) venom in vertebrate neuromuscular preparations in vitro and neutralization by antivenom

We investigated the effect of South American coralsnake (Micrurus lemniscatus lemniscatus) venom on neurotransmission in vertebrate nerve-muscle preparations in vitro. The venom (0.1-30 µg/ml) showed calcium-dependent PLA2 activity and caused irreversible neuromuscular blockade in chick biventer cervicis (BC) and mouse phrenic nerve-diaphragm (PND) preparations. In BC preparations, contractures to exogenous acetylcholine and carbachol (CCh), but not KCl, were abolished by venom concentrations ≥ 0.3 µg/ml; in PND preparations, the amplitude of the tetanic response was progressively attenuated, but with little tetanic fade. In low Ca2+ physiological solution, venom (10 µg/ml) caused neuromuscular blockade in PND preparations within ~ 10 min that was reversible by washing; the addition of Ca2+ immediately after the blockade temporarily restored the twitch responses, but did not prevent the progression to irreversible blockade. Venom (10 µg/ml) did not depolarize diaphragm muscle, prevent depolarization by CCh, or cause muscle contracture or histological damage. Venom (3 µg/ml) had a biphasic effect on the frequency of miniature end-plate potentials, but did not affect their amplitude; there was a progressive decrease in the amplitude of evoked end-plate potentials. The amplitude of compound action potentials in mouse sciatic nerve was unaffected by venom (10 µg/ml). Pre-incubation of venom with coralsnake antivenom (Instituto Butantan) at the recommended antivenom:venom ratio did not neutralize the neuromuscular blockade in PND preparations, but total neutralization was achieved with a tenfold greater volume of antivenom. The addition of antivenom after 50% and 80% blockade restored the twitch responses. These results show that M. lemniscatus lemniscatus venom causes potent, irreversible neuromuscular blockade, without myonecrosis. This blockade is apparently mediated by pre- and postsynaptic neurotoxins and can be reversed by coralsnake antivenom

Acidentes por serpentes corais (Micrurus spp.) em Campinas, Estado de São Paulo, sudeste do Brasil

Coral snakes (Micrurus spp.) are the main representatives of the Elapidae in South America. However, bites by these snakes are uncommon. We retrospectively reviewed the data from 11 individuals bitten by coral snakes over a 20-year period; four were confirmed (snake brought for identification) and seven were highly suspected (neuromuscular manifestations) cases of elapid envenoming. The cases were classified as dry-bite (n = 1, caused by M. lemniscatus; did not receive antivenom), mild (n = 2, local manifestations with no acute myasthenic syndrome; M. frontalis and Micrurus spp.), moderate (n = 5, mild myasthenia) or severe (n = 3, important myasthenia; one of them caused by M. frontalis). The main clinical features upon admission were paresthesia (local, n = 9; generalized, n = 2), local pain (n = 8), palpebral ptosis (n = 8), weakness (n = 4) and inability to stand up (n = 3). No patient developed respiratory failure. Antivenom was used in ten cases, with mild early reactions occurring in three. An anticholinesterase drug was administered in the three severe cases, with a good response in two. No deaths were observed. Despite the high toxicity of coral snake venoms, the prognosis following envenoming is good. In serious bites by M. frontalis or M. lemniscatus, the venom of which acts postsynaptically, anticholinesterases may be useful as an ancillary measure if antivenom is unavailable, if there is a delay in obtaining a sufficient amount, or in those patients given the highest recommended doses of antivenom without improvement of the paralysis or with delayed recovery.As serpentes corais (Micrurus spp.) são as principais representantes dos elapídeos na América do Sul. Todavia, acidentes com essas serpentes são raros. Foram revisados retrospectivamente os prontuários de 11 pacientes mordidos por corais num período de 20 anos. Destes 11 casos, quatro foram casos confirmados por identificação da serpente e sete como casos altamente suspeitos de envenenamento elapídico por apresentarem manifestações neuromusculares indicativas de miastenia aguda. Os casos foram classificados como não envenenados [n = 1, causado por M. lemniscatus, não recebeu antiveneno (AV)], leves (manifestações locais sem miastenia, n = 2, causados por M. frontalis e M. spp.), moderados (miastenia leve, n = 5) e graves (miastenia intensa, n = 3, um causado por M. frontalis). Os principais achados clínicos à admissão foram: parestesia (local, n = 9; generalizada, n = 2), dor local (n = 8), ptose palpebral (n = 8), fraqueza (n = 4), incapacidade de se manter na posição ereta (n = 3). Nenhum paciente desenvolveu insuficiência respiratória. O AV elapídico foi empregado em 10 casos, ocorrendo reações precoces leves em três. Em três pacientes foram administrados anticolinesterásicos, com resposta favorável em dois. Não ocorreram óbitos. A despeito da alta toxicidade dos venenos de Micrurus spp., o prognóstico do envenenamento é bom. Nos casos graves determinados por M. frontalis e M. lemniscatus, cujos venenos atuam pós-sinapticamente, o uso de anticolinesterásicos pode ser considerado caso o AV não seja disponível; caso ocorra um atraso para a sua obtenção; ou nos pacientes que receberam as mais altas doses de AV recomendadas sem melhora da paralisia ou demora na reversão desses sintomas

Effects of two fractions of swietenia macrophylla and catechin on muscle damage induced by bothrops venom and PLA(2)

Plant natural products can attenuate the myonecrosis caused by Bothrops snake venom and their phospholipases A(2) (PLA(2)). In this study, we evaluated the effects of two fractions (F4 and F6) from Swietenia macrophylla and purified catechin on the muscle damage caused by a myotoxic PLA(2) from Colombian Bothrops asper venom (BaColPLA(2)) in mice and by Bothrops marmoratus venom from Brazil in mouse phrenic nerve-diaphragm muscle (PND) preparations in vitro. Male mice were injected with PLA(2) (50 mu g) in the absence or presence of F4, F6, and catechin, in the gastrocnemius muscle and then killed 3, 7, 14, and 28 h later for histopathological analysis of myonecrosis, leukocyte infiltration, and the presence of collagen. Fractions F4 and F6 (500 mu g) and catechin (90 mu g) significantly reduced the extent of necrosis at all-time intervals. These two fractions and catechin also attenuated the leukocyte infiltration on day 3, as did catechin on day 14. There was medium-to-moderate collagen deposition in all groups up to day 7, but greater deposition on days 14 and 28 in the presence of F6 and catechin. Bothrops marmoratus venom (100 mu g/mL) caused slight (25%) muscle facilitation after 10 min and weak neuromuscular blockade (64% decrease in contractile activity after a 120-min incubation). Pre-incubation of venom with F4 or F6 abolished the facilitation, whereas catechin, which was itself facilitatory, did not. All three fractions attenuated the venom-induced decrease in muscle contractions. These findings indicate that fractions and catechin from S. macrophylla can reduce the muscle damage caused by Bothrops venom and PLA(2). These fractions or their components could be useful for treating venom-induced local damage11