This study investigates the potential of Morita-Baylis-Hillman adducts derived from carvacrol as anticancer agents. The synthesis process, involving the reaction of aromatic aldehydes with carvacrol acrylate as a Michael acceptor, resulted in stable adducts with impressive yields ranging from 60 to 92%, achieved within a maximum reaction time of 24 h. Through a screening process utilizing 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test, compound 6, identified as the acrylate/2-naphthyl adduct, emerged as the most active within the series among twelve compounds tested. Specifically, compound 6 exhibited a remarkably potent impact on neuroblastoma cell lines, particularly SH-SY5Y cells, with half-maximal inhibitory concentration (IC50) of 8.7 µM after 72 h (42 times more potent than carvacrol, IC50 = 374.1 μM). The exploration of the selectivity index (SI) against normal cell lines demonstrated an outstanding SI of 4.28 compared to other compounds. Mechanistic studies on SH-SY5Y cells revealed a concentration-dependent apoptotic effect attributed to caspase 3/7 activation. In silico modeling showcased favorable pharmacokinetic properties for compound 6, including effective absorption after oral administration. Assessment of toxicity of compound 6 profile using brine shrimp and the Irwin test indicated low toxicity, highlighting its potential for future anticancer agent development. MoritaBaylisHillman Morita Baylis Hillman agents acceptor 92 92% 2 34,5dimethylthiazol2yl2,5diphenyltetrazolium 345dimethylthiazol2yl25diphenyltetrazolium dimethylthiazolyldiphenyltetrazolium 3 4,5 dimethylthiazol yl 2,5 diphenyltetrazolium 4 5 MTT (MTT acrylate/2naphthyl acrylate2naphthyl acrylatenaphthyl acrylate/2 naphthyl adduct tested Specifically SHSY5Y SHSYY SH SY5Y SY Y halfmaximal half maximal IC (IC50 87 8 7 8. 42 (4 IC5 3741 374 1 374. μM. μM . μM) (SI 428 28 4.2 concentrationdependent dependent 37 3/ activation administration development 9 34 5dimethylthiazol2yl2 5diphenyltetrazolium 45 4, 25 2, 2naphthyl acrylate2 acrylate/ SHSY SYY (IC5 ( 4. dimethylthiazolyl 5dimethylthiazol2yl (IC

Resumo A escolha do habitat é fundamental para a busca de alimento, defesa e reprodução de um animal. As aranhas ogro são conhecidas por sua morfologia incomum, história natural e raridade. Elas são predadoras que ficam sentadas e esperam, construindo teias semelhantes a redes que são manipuladas por aranhas e lançadas em suas presas. O comportamento de caça inclui selecionar microhabitats para construção de teias que reduz a probabilidade de danos ou emaranhamento no substrato durante a captura da presa. Portanto, esperamos que Deinopis cf. cylindracea selecione superfícies lisas para forragear. Observamos D. cf. cylindracea associada a troncos lisos de Plinia cauliflora (Myrtaceae) no ambiente natural e selecionando ativamente troncos lisos em vez de troncos ásperos ou serapilheira em experimentos controlados. Essa seleção provavelmente maximiza a estratégia de forrageamento de lançar a teia em direção ao substrato. As agregações das aranhas ocorreram com mais frequência no tronco de 50 cm mais próximo do solo, onde a comunidade de presas é maior. Durante o dia, essa aranha parece escolher locais onde pode adotar uma postura semelhante a um graveto sobre a vegetação perto do chão. Caçar à noite e descansar enigmaticamente durante o dia parece ser moldado pela seleção natural para a sobrevivência e reprodução dessa espécie de aranha. alimento animal incomum raridade esperam presa Portanto cf forragear D Myrtaceae (Myrtaceae controlados 5 solo maior chão

Abstract Habitat choice is fundamental for an animal foraging, defense, and reproduction. Ogre-faced spiders are known for their unusual morphology, natural history, and rarity. They are sit-and-wait predators that build net-like webs that are manipulated by spiders and thrown at their prey. Hunting behavior includes selecting microhabitats for web construction that reduces the likelihood of damage or entanglement in the substrate during prey capture. Therefore, we expect that Deinopis cf. cylindracea selects smooth surfaces to forage on. We observed D. cf. cylindracea associated with smooth trunks of Plinia cauliflora (Myrtaceae) in the natural environment and actively selecting smooth trunks over rough trunks or litter in controlled experiments. Such selection is likely to maximize the foraging strategy of launching the web towards the substrate. Aggregations had occurred more often in the 50 cm trunk closest to the ground, where the prey community is largest. During the day, this spider appears to choose sites where it can adopt a stick-like posture upon the vegetation near the ground. Hunting at night and resting cryptically during the day appears to be shaped by natural selection for the survival and reproduction of this spider species. defense Ogrefaced Ogre faced morphology history rarity sitandwait sit wait netlike net like capture Therefore cf on D Myrtaceae (Myrtaceae experiments 5 ground largest sticklike stick species

Resumen O estado brasileiro do Acre está localizado no sudoeste da Amazônia e é caracterizado por uma vegetação de floresta tropical úmida que cobre planícies e montanhas. Até então, a composição de espécies de térmitas no estado não é conhecida. O objetivo desse estudo foi construir um checklist de espécies ou unidades taxonômicas reconhecíveis de térmitas para o estado do Acre. A amostragem foi conduzida através de expedições de campo no Parque Nacional da Serra do Divisor, no Parque Estadual Chandless, na Reserva Florestal Humaitá, e no Parque Ambiental Chico Mendes utilizando o protocolo rápido de diversidade de térmitas nas duas primeiras áreas e coletas avulsas nas demais, sem um protocolo específico. Este estudo também incluiu registros de ocorrência publicados na literature científica. Um total de 128 espécies e morfoespécies de térmitas foram encontradas no Acre, distribuídas em 59 gêneros e quatro famílias. A espécie de ocorrência mais frequente no Acre foi Heterotermes tenuis (Hagen, 1858). O estudo também identificou seis novos registros de espécies para o Brasil. Os grupos alimentares predominantes foram os humívoros e xilófagos, como esperado a partir de dados obtidos de pesquisas em florestas tropicais úmidas. Apesar do número significativo de novos registros para o Acre (112), conclui-se que ainda é necessário um esforço amostral maior, uma vez que muitas áreas do estado ainda não foram estudadas para térmitas. montanhas então conhecida Divisor Chandless Humaitá demais específico científica 12 5 famílias Hagen, Hagen (Hagen 1858. 1858 . 1858) Brasil xilófagos úmidas 112, 112 , (112) concluise conclui se maior 1 185 11 (112 18 (11 (1 (

Abstract The Brazilian state of Acre is located in the southwestern Amazon and it is characterized by a humid tropical forest vegetation that covers plains and mountains. Up to this point, the composition of termite species in the state is not known. The aim of this study was to provide a checklist of termite species or recognizable taxonomic units for the state of Acre. Sampling was conducted through field expeditions at the Serra do Divisor National Park, Chandless State Park, Humaitá Forest Reserve, and Chico Mendes Environmental Park using a standardized rapid termite inventory protocol in the first two areas and active searching collections in the others, without a specific protocol. This study also included occurrence records published in the scientific literature. A total of 128 species and morphospecies of termites were found in Acre, distributed across 59 genera and four families. The most frequently occurring species in Acre was Heterotermes tenuis (Hagen, 1858). The study also identified six new species records for Brazil. The predominant feeding groups were soil-feeders and wood-feeders, as expected from data obtained from surveys in humid tropical forests. Despite the significant number of new records for Acre (112), it is concluded that a larger sampling effort is still required, as many areas of the state have not yet been studied for termites. mountains point known Reserve others literature 12 5 families Hagen, Hagen (Hagen 1858. 1858 . 1858) Brazil soilfeeders soil feeders woodfeeders, woodfeeders wood feeders, wood-feeders forests 112, 112 , (112) required 1 185 11 (112 18 (11 (1 (

Resumo Os térmitas estão entre os insetos consumidores de liquens e representam um potencial dispersor desses simbiontes. Este estudo avaliou a vitalidade de fotobiontes e micobiontes depois de terem passado pelo trato digestivo de Constrictotermes cyphergaster. O percentual de algas vivas e mortas foi verificado ao longo do canal alimentar de 450 operários, oriundos de cinco colônias amostradas em Caatinga Dry Forest, NE, Brazil. Um crescimento progressivo na mortalidade das algas foi observado no sentido papo, pança e reto, porém mais de 40% das algas presentes nas fezes apresentaram sinais de vitalidade. A morfologia dos fotobiontes foi diferente entre células extraídas de talos in natura e algas presentes nas fezes dos térmitas. As células do fotobionte apresentaram seu citoplasma mais encolhido, após a passagem pelo canal alimentar de C. cyphergaster. Também houve um aumento entre o espaço da parede celular e a membrana do citoplasma das algas encontradas nas pelotas fecais dos térmitas. Apenas quatro esporos quebrados foram encontrados no intestino dos cupins, o que inviabilizou a análise de vitalidade dessas células. O registro da vitalidade de fotobiontes nas pelotas fecais dos térmitas é um indicativo de dispersão endozoocórica, remetendo que a relação entre esses insetos e os liquens pode ir além de uma interação trófica. simbiontes cyphergaster 45 operários Forest NE Brazil papo reto 40 encolhido C cupins endozoocórica trófica 4

Abstract Termites are among the insects that consume lichens and may be potential dispersers of these symbionts. This study evaluated the vitality of photobionts and mycobionts after passing through the digestive tract of Constrictotermes cyphergaster. The percentage of live and dead algae was verified throughout the alimentary canal of 450 workers, originating from five sampled colonies in the Caatinga Dry Forest, NE, Brazil. A progressive growth in algae mortality was observed in the crop, paunch and rectum, however more than 40% of the algae found in faeces presented signs of vitality. Photobiont morphology was different between cells extracted from thallus in natura and algae present in termite faeces. The photobiont cells presented more shrunken cytoplasms after passing through the alimentary canal of C. cyphergaster. There was also an increase between the cell wall space and the cytoplasm membrane of algae found in the termite faecal pellets. Only four broken spores were found in the intestine, which made the vitality analysis unfeasible for these cells. The record of photobiont vitality in termite faecal pellets is indicative of endozoochoric dispersal, suggesting that this relationship between insects and lichens extends beyond a trophic interaction. symbionts cyphergaster 45 workers Forest NE Brazil crop rectum 40 C intestine dispersal interaction 4

Cancer treatment represents one of the main scientific study targets today, mainly due to the pronounced side effects arising from chemotherapy. This study reports the synthesis, characterization, and anticancer activity of ten compounds from the Morita-Baylis-Hillman reaction. Ethylene glycol diacrylate was used as a double Michael acceptor in reactions with isatin derivatives to give homodimers of 3-hydroxyindolin-2-one core, recognized in the literature for its extensive pharmacological profile. The use of 1,4-diazabicyclo[2,2,2]octane (DABCO) as a catalyst and room temperature were the optimal conditions for the study reaction. The isolated yields were up to 63%, with most reaction times inferior to 24 h, some as fast as 15 min. The anticancer potential of the synthesized dimers was evaluated in vitro against three cancer strains, resulting in average inhibitory concentrations up to 0.72 µM. It was also found that the best performing homodimers are more active than their monomeric counterparts. Considering the promising selectivity indices observed, the preliminary results obtained here act as a basis for broader tests regarding the effectiveness of homodimeric adducts against cancer cells. today chemotherapy synthesis characterization MoritaBaylisHillman Morita Baylis Hillman 3hydroxyindolin2one hydroxyindolinone 3 hydroxyindolin 2 core profile 1,4diazabicyclo2,2,2octane 14diazabicyclo222octane diazabicyclooctane 1,4 diazabicyclo 2,2,2 octane 1 4 DABCO (DABCO 63 63% h min strains 072 0 72 0.7 µM counterparts observed cells 4diazabicyclo2 2octane 14 1, 222 2,2, 6 07 7 0. 4diazabicyclo 22 2,2 2,

CNFD (6b,7-dihydro-5H-cyclopenta[b]naphtho[2,1-d]furan-5,6(9aH)-dione) is a semisynthetic naphthoquinone derived from lawsone that has cytotoxic action in different tumor lines and anticancer activity in vivo. Therefore, this molecule is a relevant candidate for drug development, but there is still no information on its human metabolism and systemic elimination. This study aimed to investigate the in vitro metabolism of this naphthoquinone by human liver microsomes. Initially, in order to determine the in vitro enzymatic kinetic parameters, a high performance liquid chromatography (HPLC) method to quantify the CNFD was developed and validated. In addition, the enzymatic kinetic data, the predicted pharmacokinetic in vivo parameters and the phenotyping study were presented. The main metabolism sites and metabolites have been suggested in silico. The developed HPLC method was linear, reproducible, selective, accurate, and stable. The enzymatic kinetic parameters revealed a sigmoidal profile. In vitro to in vivo extrapolation hepatic metabolic clearance was 10.39 mL min-1 kg-1 protein and the liver extraction rate was 51%. The clearance in vivo associated with a hepatic extraction ratio indicates that the hepatic metabolism is the main route of elimination. Although all cytochrome P450 enzymes evaluated metabolized CNFD, CYP2C9 and CYP3A4 showed higher metabolic capacity. For the first time, metabolism studies of CNFD were demonstrated.

Abstract Background: Basal cell and squamous cell carcinomas (BCC and SCC) are the most common types of cancer worldwide. Intraoperative assessment of surgical margins by frozen section has been widely used to ensure disease-free margins. The intraoperative ‟en face” freezing technique evaluates all peripheral and deep margins. Objective: To report the results of the ‟en face” freezing technique in relation to tumor recurrence and agreement with paraffin-embedded tissue examination. Methods: Retrospective analysis of patients undergoing surgical excision of BCC and SCC at the A. C. Camargo Cancer Center, Brazil. Results: This study included 542 skin carcinomas, which were excised from 397 patients. A total of 201 male patients (50.6%), and 196 female patients (49.4%) were assessed, whose mean age was 64 years. The tumors were mostly located on the head and neck region (87.8%). BCC corresponded to 79.7% of the cases. The mean follow-up was 38 months. Tumor relapse occurred in 0.86% of the primary tumors and 3.7% of recurrent tumors. The result of the intraoperative ‟en face” frozen section evaluation was in agreement with the final result of the anatomopathological examination (paraffin test) in 98% of the lesions. Study limitations: Not having a minimum follow-up time of 5 years for all patients. Conclusion: The ‟en face” freezing technique shows low tumor relapse, being reliable and safe to guarantee negative surgical margins of the tumor.

ABSTRACT Objective: The present study investigated the time needed to achieve a steady state for an accurate assessment of resting energy expenditure (REE) in adolescents with healthy weight and obesity. Materials and methods: Thirty adolescents aged 12-17 years were assigned to a group with healthy weight (GHW; n = 12, body mass index [BMI] 22.5 ± 3.6 kg/m2) and another group with obesity (GO; n = 18, BMI 34.1 ± 5.2 kg/m2). Participants underwent test-retest reliability of REE assessment as follows: a) 24 h of abstention from physical exercise, soft drinks, or caffeine; b) fasting for ~12 h; c) acclimation period of 10 min; d) 30-min assessment in a supine position. Results and discussion: A significant change occurred during the 30 min in REE. Significant differences existed between consecutive means until the 20th and 25th min for the GHW and GO, respectively. Although significant differences between trials 1 and 2 were detected during the first 5-10 min of assessment, the REE for each 5-min time point exhibited high test-retest reliability across trials in both groups (intraclass correlation coefficients range 0.79-0.99). Conclusion: The following recommendations are provided to promote accurate assessment of REE among adolescents: a) initiate the REE assessment with 10 min of acclimation to decrease restlessness; b) determine REE for a minimum of 20 min if healthy weight and 25 min if obesity; c) determine REE for a further 5 min, with the average of this last 5 min of REE data being regarded as the REE.

A conciliação compreende uma forma alternativa de equacionar os processos trabalhistas que acompanha o surgimento da Justiça do Trabalho no Brasil. Recentemente, a conciliação trabalhista passou por mudanças relativas aos desdobramentos da “Política Nacional de tratamento adequado aos conflitos de interesses” do Conselho Nacional de Justiça (CNJ), sendo a adoção dessa política judiciária alvo de controvérsias na comunidade jurídica trabalhista. Este artigo atenta ao conteúdo moral das disputas sobre os sentidos da conciliação trabalhista, a partir da análise dos repertórios normativos mobilizados pelos palestrantes de uma audiência pública promovida pelo CNJ em 2016, que visou elaborar uma regulamentação própria à Justiça do Trabalho. Busca-se demonstrar que esses repertórios compõem uma gramática moral cujos princípios de justificação são a defesa da proteção ao trabalhador na efetivação dos direitos sociais nos acordos e a humanização do judiciário, tendo como apoio normativo os ideais de harmonia e empoderamento das partes na resolução do conflito.

Conciliation comprises an alternative way of settling labor cases that accompanies the emergence of Labor Justice in Brazil. Recently, labor conciliation has undergone a process of change related to the development of the “National Policy for adequate treatment of conflicts of interest” of the National Council of Justice (CNJ), and the adoption of this judicial policy is the target of controversy in the labor legal community. This article investigates the moral content of the disputes about the meanings of labor conciliation, from the analysis of the normative repertoires mobilized by the speakers of a public hearing promoted by the CNJ in 2016, which aimed to elaborate a regulation proper to the Labor Justice. With this, we seek to demonstrate that these repertoires compose a moral grammar whose justification principles are the defense of worker protection in the effectiveness of social rights in the agreements and the humanization of the judiciary, with the ideals of harmony and empowerment of the parties in the conflict resolution as normative support.

La conciliation comprend une forme alternative d’égaliser des processus de travail qui accompagne l’émergence du Tribunal du travail au Brésil. Récemment, la conciliation du travail a connu un processus de changement lié au cadre des développements de la « Politique nationale de traitement adéquat des conflits d’intérêts » du Conseil National de la Justice (CNJ), et l’adoption de cette politique judiciaire est la cible de controverses dans la communauté juridique du travail. Cet article examine le contenu moral des disputes sur les significations de la conciliation du travail, à partir de l’analyse des répertoires normatifs mobilisés par les intervenants d’une audition publique promue par le CNJ en 2016, qui visait à élaborer une réglementation propre du Tribunal du travail. On essaie de démontrer que ces répertoires comprennent une grammaire morale dont les principes de justification sont la défense de la protection du travailleur dans l’effectivité des droits sociaux dans les accords et l’humanisation de l’appareil judiciaire, avec support normatif des idées d’harmonie et de responsabilisation des parties dans la résolution des conflits.

In the present work, the sol-gel synthesis method was employed as strategy to obtain a magnetic and mesoporous silica-niobia material. The planned synthesis was based on the hetero-condensation of niobium and silicon alkoxide precursors, in the presence of spherical magnetite particles. The resulting material presented interesting characteristics such as magnetism, large mesopores, in the range from 20 to 50 nm, and 68 m2 g-1 of surface area. These features allowed its use as modifier of carbon paste electrode for p-nitrophenol determination, since niobia has never been used in electrochemical sensors for the determination of nitrophenol compounds. By using differential pulse voltammetry technique, the electrode can be applied in a wide range of p-nitrophenol concentration, from 10 to 490 μmol L-1, with a limit of detection of 1.2 µmol L-1 and sensitivity up to 0.60 µA L µmol-1. The proposed electrode presented good sensitivity and selectivity and it was applied in real water samples.

Morita-Baylis-Hillman adducts (MBHA) is a class of polyfunctional molecules that has been standing out due to their versatility and expressive biological activities. Therefore, this paper describes the synthesis and antiproliferative activity of some new MBHA/7-choroquinoline hybrids. The Michael acceptors were obtained starting from 4,7-dichloroquinoline which were submitted to the Morita-Baylis-Hillman reaction with ortho, meta and para-nitrobenzaldehyde. The in vitro screening of the synthetized MBHA against NCI-H292, HCT-116 and MCF-7 cancer cells suggests the influence of the spacer chain in its inhibition potential. The 50% inhibitory concentration (IC50) obtained in the antiproliferative assay using MCF-7, HCT-116, HL-60 and NCI-H292 cancer cells indicate expressive cytotoxic potential of the adducts containing nitro group in the ortho position, with IC50 of 4.60 µmol L-1. MBHA/7-choroquinoline hybrids were more active than MBHA described in literature, indicating the improvement of the cytotoxic effect due to 7-chloroquinoline moiety in the molecular structure, with maximum selectivity index values of 11.89.

RESUMO: A leishmaniose visceral é a forma mais grave de um complexo de doenças humanas e animais, denominado leishmaniose, endêmica em 70 países. É imprescindível desenvolver e oferecer tecnologias capazes de aumentar a capacidade de resolução dos programas de controle desta zoonose. Na busca por inovações tecnológicas em saúde, principalmente na vigilância ambiental, o objetivo é desenvolver um aplicativo móvel (App) para smartphones a fim de facilitar e sistematizar a notificação de casos positivos de leishmaniose visceral canina (LVC) por médicos veterinários que atuam em clínicas auxiliando a vigilância sanitária municipal, na gestão desta zoonose. Para tanto, foi desenvolvido um App, C7 LVC - Sistema de Notificação da Leishmaniose Visceral Canina, com formatação baseada no software CR Campeiro 7®. A tecnologia criada possibilita o preenchimento de lacunas importantes nos sistemas de informação, facilitando a transmissão de dados e a utilização desses dados pelos órgãos da gestão pública para a tomada de ações de prevenção e controle da LVC.

ABSTRACT: Visceral leishmaniasis is the most severe form of a human and animal disease complex entitled leishmaniasis, which is endemic to 70 countries. It is imperative to develop and offer technologies capable of increasing the resolution ability of control programs of this zoonosis. In the search for technological innovations in health, especially in environmental surveillance, the objective is to develop a mobile application (App) for smartphones in order to facilitate and systematize the notification of positive cases of canine visceral leishmaniasis (CVL) by veterinarians working in clinics for assisting the municipal health surveillance in the management of this zoonosis. Thus, we developed an App, C7 LVC - Canine Visceral Leishmaniasis Notification System, with formatting based on the CR Campeiro 7® software. The technology created enables the filling of important gaps in information systems, facilitating the transmission of data and the use of this data by public management bodies to take CVL prevention and control actions.

We present an electroanalytical method using square-wave anodic stripping voltammetry on electrochemically-treated screen-printed gold electrodes to the simultaneous determination of lead(II), copper(II) and mercury(II) in struvite (natural fertilizer produced from urine). Electrochemical treatment via cyclic voltammetry of the working electrodes increased surface rugosity that improved the electroanalytical responses for the three metals. Under optimized conditions and using a deposition time of 90 s, the proposed method presented the following limit of detection values: 1.3 µg L-1 for lead(II), 2.0 µg L-1 for copper(II) and 0.9 µg L-1 for mercury(II). Struvite samples were easily dissolved in supporting electrolyte solution (0.05 mol L-1 HCl). Satisfactory recovery values between 91 and 111% were obtained for the analysis of spiked samples. Hence, we can infer that the proposed electroanalytical method is an effective alternative for the determination of trace metals, since it provides precise and accurate direct analyses, with rapid responses without interference from sample matrix and enabling in field analysis.

Resumo A produção de serapilheira é essencial para a ciclagem de nutrientes em ecossistemas terrestres. De Novembro de 2009 a Outubro de 2011, foi analisada a produção de serapilheira em duas áreas de Caatinga, um tipo de Floresta Tropical sazonalmente Seca localizada no Cariri Paraibano, na região do semiárido da Paraíba, Nordeste do Brasil. Uma das áreas, Reserva Particular do Patrimônio Natural - RPPN - Fazenda Almas, é legalmente protegida, ao contrário da outra, Fazenda Moreiras. Os objetivos foram avaliar o efeito da precipitação, evapotranspiração e estrutura da vegetação sobre a dinâmica temporal e espacial da produção de serapilheira. Oito pontos de amostragem foram escolhidos aleatoriamente em cada localidade, e dois coletores de 1 m2 foram instalados a 50 m um do outro. O material coletado foi triado, secado e pesado. Adicionalmente, foram registradas as características (densidade, riqueza de espécies, altura e área basal média) das espécies arbóreo-arbustivas na parcela com um raio (r) de 10 m ao redor de cada coletor. A produção total de serapilheira foi 4,500 Kg ha-1 yr-1 para a Fazenda Almas e 3,300 kg ha-1 yr-1 para a Fazenda Moreiras; estes valores estão dentro da faixa esperada para as Florestas Tropicais sazonalmente secas. A variação inter e intranual na produção de serapilheira foi positivamente correlacionada com as taxas de precipitação e evapotranspiração, e quatro meses depois das maiores taxas de precipitação, houve uma diminuição acentuada na serapilheira coletada durante a estação seca. Além disso, as contribuições das frações de material foram distintas com a fração de folha representando mais que 60% da serapilheira, e a estrutura da vegetação explicou 75% da variação na produção de serapilheira. Portanto, os fatores climáticos e a estrutura da vegetação afetam a dinâmica temporal e espacial da produção de serapilheira e, consequentemente, influenciam a dinâmica de nutrientes na região semiárida do Brasil.

Abstract The production of litterfall is essential for nutrient cycling in terrestrial ecosystems. From November 2009 to October 2011, analyzed the monthly litterfall production in two areas of Caatinga, a type of Seasonally Dry Tropical Forest located in the Cariri Paraibano, in the semiarid region of the Paraíba, Northeastern Brazil. One of the areas, Private Natural Heritage Reserve (RPPN) Fazenda Almas, is legally protected, and the other, Fazenda Moreiras, does not. The aims were to evaluate the effects of precipitation, evapotranspiration and vegetation structure on the temporal and spatial dynamics of litterfall production. Eight sampling points were randomly chosen at each site, and two 1 m2 collectors were installed 50 m apart from each other. The collected material was sorted, dried and weighed. Additionally, the characteristics (density, species richness, height and mean basal area) of the tree-shrub stratum in plots with a 10 m radius surrounding each collector. Total litterfall production was 4,500 kg ha-1 yr-1 for Fazenda Almas and 3,300 kg ha-1 yr-1 for Fazenda Moreiras; these values were within the expected range for Seasonally Dry Tropical Forests. The inter- and intra-annual variation in litterfall production was positively correlated with precipitation and evapotranspiration rates, and four months after the highest precipitation rates, there was a marked decrease in litterfall occurred during the dry season. Furthermore, the contributions of the material fractions were distinct with the leaf fraction representing for more than 60% of the litterfall, and the vegetation structure explained 75% of the variation in litterfall production. Therefore, climatic factors and vegetation structure affect the temporal and spatial dynamics of litterfall production and consequently influence nutrient dynamics in the semiarid region of Brazil.