Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time, and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space. While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes, vast areas of the tropics remain understudied. In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity, but it remains among the least known forests in America and is often underrepresented in biodiversity databases. To worsen this situation, human-induced modifications may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge, it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

475 °C Embrittlement in a duplex stainless steel UNS S31803

The susceptibility of a duplex stainless steel UNS S31803 to thermal embrittlement at 475 °C was evaluated by means of mechanical tests (impact energy and hardness), magnetic measurements (hysteresis and thermomagnetic analysis) and scanning electron microscopy. The results show that the material undergoes severe embrittlement and hardening in the first 100 h. The corrosion resistance of the ferrite phase in a 10%HNO3 + 0.05%HF solution deteriorated after 500 h of ageing. The Curie temperature (Tc) was the most sensitive magnetic property to the microstructural changes that promote embrittlement. Tc increases with ageing time due to the progressive reduction of chromium in the Fe-rich matrix during spinodal decomposition

Fornecimento de volumoso para bezerros pré-ruminantes Roughage for pre-ruminant calves

O presente trabalho avaliou a performance de bezerros mestiços HolandêsxZebu, do nascimento aos 90 dias de idade, desaleitados aos 56 dias, com acesso ou não a volumoso. O ensaio foi conduzido na Estação Experimental de Itaguaí da PESAGRO-RIO, em Seropédica, RJ, no período de janeiro a abril de 2000. Foram utilizados 27 bezerros, distribuídos em blocos ao acaso, de acordo com o peso ao nascer e com o sexo, nos seguintes tratamentos experimentais: (1) Concentrado; (2) Concentrado+pasto de capim-estrela (Cynodon nhenfluensis), e (3) Concentrado+feno de alfafa (Medicago sativa). Os animais foram separados das mães 24 horas após o nascimento e mantidos em baias individuais. Todos os animais receberam colostro até o 3º dia de vida e, a partir daí, quatro litros de leite integral/animal/dia, além de concentrado comercial (18%PB), até o máximo de 2,0kg/animal/dia, a partir da segunda semana de vida. Os animais do tratamento 2 tiveram acesso aos piquetes, manejados em rodízio, a partir do 15º dia de vida, no período das 8h às 14h, e aqueles do tratamento 3 receberam feno de alfafa (18%PB) picado, à vontade, a partir do 8º dia de vida. Não houve diferença (P>0,05) entre os tratamentos 1 e 3; entretanto, aqueles submetidos ao tratamento 2 consumiram menor (P<0,05) quantidade de concentrado. Não houve diferença (P>0,05) para consumo total de matéria seca e eficiência alimentar entre os tratamentos 1 e 3 e para ganho de peso médio diário, perímetros abdominal e torácico, incidência de diarréias e corrimento nasal entre os três tratamentos. O fornecimento de volumoso para bezerros pode ser feito a partir da 8ª semana de idade, sem prejuízos para o seu desenvolvimento, desde que os animais tenham à sua disposição concentrado inicial desde a segunda semana de idade.<br>This experiment aimed to evaluate the growth of Holstein Zebu crossbred calves, from birth to 90 days of age, early weaned, with or without available roughage from the second week of age on. The trial was carried out at the Itaguaí Experimental Station, from PESAGRO-RJ, from January up to April, 2000. Twenty-seven calves were used, randomly assigned to blocks according to sex and birth weight, in the following experimental treatments: (1) only starter; (2) starter plus Cynodon nhenfluensis paddocks grazed from the 15th day of age on; and, (3) starter plus Medicago sativa hay. Calves were separated from their dams twenty-four hours after birth and kept to individual pens. All animals received colostrum up to the 3rd day of age and, from there on, four litters of whole milk/animal/day, up to the 56th day of age, and commercial starter (18%CP) up to a maximum of 2.0kg/animal/day from the second week of age on. Animals from treatments 1 and 3 were kept on their pens up to 70 days of age, those from treatment 3 received, in separated feeders, chopped alfalfa hay (18%CP, particle size of 5cm), ad libitum, from the 8th day on. Animals in treatment 2 had access to paddocks from 8:00 to 14: 00h. Milk, starter and hay intakes, as well as diarrhoea and nasal flow incidences were measured daily up to 70 days of age. Body weight and barrel and heart girth were taken weekly. There were no difference (P>0.05) between calves fed roughage (treatments 2 and 3) for starter intake; however, animals allowed to graze showed lower (P<0.05) starter intake. Average total dry matter intake and feed efficiency were similar (P>0.05) for treatments 1 and 3. There were no differences (P>0.05) among treatments for average daily weight gain, as well as diarrhea, nasal flow incidences and barrel and heart girth. It was concluded that roughage may be supplied to calves from day 56th of age on, without impairing their development, when starter is offered since the second week of age

Desempenho, temperatura retal e freqüência respiratória de novilhas leiteiras de três grupos genéticos recebendo dietas com diferentes níveis de fibra Performance, rectal temperature and respiratory ratio of dairy heifers from three genetic groups fed diets with different levels of fiber

Foram avaliados o desempenho, a temperatura retal e a freqüência respiratória de novilhas leiteiras de três grupos genéticos, Holandês (H) &times; Zebu (Z) (7/8 HZ, 15/16 HZ e Holandês puro por cruza - HPC), mantidas em sistema de confinamento e recebendo dietas com diferentes níveis de fibra em detergente neutro (30 e 60%) utilizando-se como volumoso capim-elefante (Pennisetum purpureum, Schum., cv. Mineirão) picado. Determinaram-se o consumo, o ganho de peso e as respostas fisiológicas desses animais considerando as condições climáticas nos dias experimentais. O experimento foi delineado segundo esquema fatorial 3 &times; 2 (grupo genético &times; nível de fibra), em blocos casualizados, com quatro repetições. Os valores relativos às variáveis fisiológicas foram analisados em parcelas subdivididas no tempo. Os consumos médios de MS, FDN e FDA foram de 10,13; 2,69 e 1,45 kg/dia e de 2,70; 0,71 e 0,38%PV, respectivamente, para a dieta com baixa fibra e de 10,68; 6,17 e 2,92 kg/dia e 2,90; 1,67 e 0,79%PV para a dieta com alta fibra para ganhos de peso diários de 1,28 e 0,92 kg/dia, respectivamente. O consumo de MS em %PV pelos animais HPC foi maior (2,94%PV) que pelos animais 7/8HZ (2,65%PV). As novilhas que receberam a dieta com 60% de FDN consumiram maior quantidade de MS, FDN e FDA e apresentaram menores ganhos de peso por dia em relação àquelas que receberam a dieta com 30% de FDN. Novilhas HPC consomem maior quantidade de MS (%PV) que as 7/8 HZ, tanto em dietas com 30% de FDN quanto com 60% de FDN. Nas condições de ambiente térmico observadas durante o período experimental, novilhas 7/8 HZ, 15/16 HZ e HPC mantêm a temperatura retal dentro de limites fisiológicos considerados normais.<br>This work aimed to evaluate the performance, rectal temperature and respiratory ratio of dairy heifers, from three genetic groups Holstein &times; Zebu (7/8HZ, 15/16HZ, Graded Holstein-GH), confined and fed total mixed diet with different levels of neutral detergent fiber (30 and 60%), using chopped elephantgrass (Pennisetum purpureum, Schum., cv. Mineirão) as forage. Intake, weight gain and physiological responses of these animals were determined under different environmental conditions. The experiment was conducted according to a 3 &times; 2 factorial arrangement (genetic group &times; fiber level), in a completely randomized design, with three replicates. The values related to physiological responses were analyzed according to split plot design in the time. Average intakes of DM, NDF and ADF of 10.13, 2.69, and 1.45 kg/day and 2.70, 0.71 and 0.38%LW, respectively, were observed for the diet with low fiber content versus 10.68, 6.17, and 2.92 kg/day and 2.90,1.67, and 0.79%BW for the diet with high fiber content and weight gains of 1.28 and 0.92 kg/day, respectively were obtained. The DM intake in %BW for GH animals was higher (2.94 %BW) than for animals 7/8HZ (2,65%LW). When elephantgrass was used as forage only, heifers fed diets with 60% of NDF ingested greater amount of DM, NDF and ADF and gained less weight per day in relation to those fed diets with 30% of NDF. GH heifers ingested more DM (%LW) than 7/8 HZ heifers, for both diets with 30 and 60% NDF. In thermal environment conditions observed during the experimental period, heifers 7/8HZ, 15/16HZ and GH keep the rectal temperature inside the physiological limits considered normal