Matemáticas Financieras
Determine a cuánto asciende la deuda de una persona si el banco le prestó 2/3 de $900,000, y ahora es 6/8 menor que hace 5 meses.
AREA 1 BANCO ESPECIAL UNAM
Cuando se utilizan clorofluorocarbonos, ¿Qué capa de la tierra se ve afectada?
FISICA SIMULADOR PARA LA UNAM
Desde cierta altura se deja caer una piedra en un estanque ¿Cómo son las ondas que se forman en el agua?
test IPN
"En la Ciudad de México, cada rincón cuenta una historia distinta. Las plazas, mercados y calles conservan tradiciones que han perdurado por siglos, mientras el bullicio diario da vida a esta gran metrópoli."
¿Qué tipología textual se observa predominantemente en el párrafo anterior?
Cálculo Diferencial e Integral
Elija la derivada de la función trigonométrica.
f(x)=3 tan x
QUIMICA SIMULADOR PARA LA UNAM
Unión física de dos sustancias que no se alteran químicamente y conservan sus propiedades.
Exani III -> Metodología de la investigación
En una investigación realizada por dermatólogos se analiza la relación entre la aplicación de ácido hialurónico en la piel y la disminución de las arrugas en un grupo de adultos de diferentes edades. Para ello, se les aplica un instrumento con una serie de aseveraciones y se les pide que en una escala del 0 al 100, en donde el 0 es la ausencia del atributo y 100 es la presencia total de este, respondan con base en su opinión.
¿Cuál es el nivel de medición de las variables en la situación de investigación planteada?
Inglés
Choose the correct answer for each question according to the information in the text. Each line is numbered to help you identify them quickly.
| Sunflowers Make Bees Poop—a Lot. Here's Why That's Good | |
|---|---|
| Paragraph | Text |
| [1] | Bumblebees and other pollinators face many threats, including pesticide exposure, |
| [2] | climate change, habitat loss due to agriculture and development, and pathogens |
| [3] | that ravage multiple species. But a recent finding may help lighten their load. |
| [4] | Previous studies have shown sunflower pollen can work like a medicine for |
| [5] | bumblebees afflicted by a parasite called Crithidia bombi, a single-celled organism |
| [6] | that takes up residence in the bee's gut [and harms their health]. But scientists couldn't |
| [7] | explain how sunflower pollen vanquished C. bombi—did it boost the bees' immune |
| [8] | function, or perhaps poison the parasite directly? |
| [9] | New research, published in the Journal of Insect Physiology, shows the answer is |
| [10] | deceptively simple. "Sunflower pollen makes bumblebees poo a whole lot," says lead |
| [11] | author Jonathan Giacomini, which flushes the parasite out. |
| [12] | Plant products like nectar and pollen are a treasure trove of potential insect medicines |
| [13] | that scientists are just beginning to understand, he adds. "There are natural things out |
| [14] | there that bees are interacting with that can be beneficial for them," Giacomini says. |
| [15] | And by making changes to the landscape, scientists hope we can help give bees a |
| [16] | fighting chance. |
| [17] | Plant power |
| [18] | If you happen upon a fuzzy, buzzing, flying creature in eastern North America, there's |
| [19] | a strong chance it's a common eastern bumblebee (Bombus impatiens). Yellow and |
| [20] | black striped with a rump covered in soft hairs, they're social insects that live in |
| [21] | colonies and love a good crevice—they build their homes in birdhouses, woodpiles, |
| [22] | abandoned burrows, and dense grasses. |
| [23] | [They] are important pollinators, both in the wild and in agriculture, where they're raised |
| [24] | and used to pollinate crops including tomatoes and pumpkins. Like other pollinators, |
| [25] | bumblebees face many threats, and C. bombi isn't even the biggest bumblebee |
| [26] | bugaboo. On its own, the parasite doesn't have much of an effect on a bumblebee's |
| [27] | health. But when food is scarce, C. bombi can shorten a bee's lifespan and even |
| [28] | reduce the number of young queens a colony can produce. |
| [29] | Lynn Adler is an evolutionary ecologist at the University of Massachusetts Amherst |
| [30] | who studies interactions between plants and insects. For years, she and longtime |
| [31] | collaborator Rebecca Irwin at North Carolina State University suspected pollinators |
| [32] | might be getting dosed by flowers since plants often invest chemically active |
| [33] | compounds into their nectar and pollen to help their genetic payload arrive at |
| [34] | its destination. |
| [35] | "Many plant defensive compounds can be medicinal at certain doses," Adler says. After |
| [36] | all, "most of our human medicines come from plants." |
| [37] | Giacomini discovered the effect of sunflower pollen as an undergraduate working in |
| [38] | Adler's lab in 2018. From [these] very first tests, sunflower pollen dramatically reduced |
| [39] | C. bombi parasite load in common eastern bumblebees, often clearing infection |
| [40] | completely. "We've been shocked at how consistent and effective sunflower pollen |
| [41] | has been," Adler says. |
| Elizabeth Anne Brown, National Geographic | |
What is the most important idea in lines 12 to 16?
Ciencias Experimentales
Calcule el valor de una carga eléctrica cuando se encuentra a 34 cm de otra carga de +6 μC. La magnitud de la fuerza es de 0.8 N.
Considere k = 9 x 109 Nm2/C2.
Química IPN
Los elementos _________ presentan baja electronegatividad y ceden electrones fácilmente.
Exani