From Scotland to Japan, these multiday treks offer adventure and a truly immersive experience

From Setsubun in Japan to Fèt Gede in Haiti, these festivals relish in the macabre

Eight years into living in Longyearbyen, on the Norwegian archipelago of Svalbard, I embrace the seasonal plunge into total darkness

See photographs of the beautiful natural wonders from the Smithsonian Magazine Photo Contest

These amazing images from the Smithsonian Magazine Photo Contest show the Arctic animals at their fierce but adorable best

Michelle Frankfurter tells the stories of these young migrants and also those of the thousands who jump aboard “the death train”

From swirling aurora borealis to bioluminescent beaches, these award-winning photographs capture rare views of our world at night

It's curtains for the NASA mission's close relationship with the satellite

The surge of hungry four-legged visitors to Belushya Guba is part of a larger trend

The trend is a result of women deciding to have children later in life and the use of medically assisted reproduction methods

Renaissance paintings, medieval archives, cloistered orchards—how one Italian scientist is uncovering secrets that could help combat a growing agricultural crisis

These images from the Smithsonian Magazine Photo Contest show how communities in Mexico and beyond mark Día de los Muertos.

A clinical social worker explains the vital role of the old-fashioned rotary phone for those dealing with death and loss

On the island of Laeso in Denmark, one man is reviving the lost art of eelgrass thatching and, in doing so, bringing attention to a plant that has great potential

In the international competition, people with physical disabilities put state-of-the-art devices to the test as they race to complete the tasks of everyday life

Manufacturing a Bentley in the traditional way is a time-consuming nod to their brand heritage. Each hand-crafted wheel can take 4.5 hours to finish

Adverse weather has cancelled ferry crossings between Newfoundland and Labrador and Nova Scotia heading into the long weekend.

Police have reported that a man was fatally electrocuted in Torbay on Saturday evening. Two others are being treated for injuries.

After a year of negotiations, the postal union has given Canada Post a 72-hour strike notice. At a solidarity rally in St. John's last week, local president Craig Dyer says a strike could mean parcels — including Christmas presents — won't make it to rural communities.

Pat White, an entrepreneur who launched EVAS Air and the Gander Flight Training, has died. He was 69 years old.

Ashley Hickey, a parent of a kid with celiac disease, is concerned that Nova Scotia's new school program does not offer any 100 per cent guaranteed gluten-free options.

A researcher studying the rise of extremism in Atlantic Canada warns Ku Klux Klan Halloween costumes are just one example of an insidious effort by far-right groups to normalize hateful attitudes.

A candidate for the Nova Scotia NDP has apologized and is no longer running for the party in the provincial election after her comments on Israel and the Holocaust drew concern from the Jewish organizations. 

The L'nu Sipuk Kina'muokuom school observed Indigenous Veterans Day with an event on Friday. Students, faculty and staff got together to honour Mi’kmaw military veterans and RCMP members.

Independent Elizabeth Smith-McCrossin is back on the campaign trail in Cumberland North, but opponents say the riding would be better represented by an MLA from an official party. 

A Port Hawkesbury woman has long imagined a Remembrance Day with her great-uncle's war medals. It will happen this year for the first time thanks to some sleuthing and the kindness of her great-uncle's foster family.

RCMP are investigating after officers discovered human remains in an abandoned, burned vehicle in Greenhill, N.S.

As Nova Scotia politicians make their fall election promises, Julie Leggett is urging them to commit to helping people on income assistance stay cool during heat waves.

As Week 3 of the provincial election campaign begins, there are questions about how Nova Scotia's major political parties plan to combat the rising number of opioid overdose deaths. 

Some Nova Scotia municipal leaders are defending a funding stream the federal Conservatives say they will cut if elected, calling it a "game changer."

Building highways isn't the only solution to the growing problem of traffic congestion in and around the Halifax Regional Municipality, says the head of an organization that advocates for rail-based public transit.

The new mayor and council are planning big changes for the Cape Breton Regional Municipality, and one of those is at the top of the staff organizational chart now that chief administrative officer Marie Walsh is set to retire.

Elections Nova Scotia is investigating PC candidate Susan Corkum-Greek's campaign to determine whether it broke the law by handing out gift cards on Saturday outside a Tim Hortons in Lunenburg, N.S. 

The Montreal English Theatre Awards ceremony is being held this evening at Le Gesù theatre. For the community, it's a time to celebrate their achievements and resilience coming out of the pandemic, together.

Loved ones, friends, and people from across the city have all come together to support each other at Pastel Rita, the café Jocelyn Després helped so many call home.

The union representing dockworkers in Montreal says Canada's labour minister forcing its members back to work at ports in Montreal and Quebec City marks a "dark day for workers' rights."

Quebec provincial police have confirmed that the body found in a Montreal nature park on Oct. 30 was that of kidnapping victim and cryptocurrency influencer Kevin Mirshahi.

Amid rapid global advances and deployment of artificial intelligence technologies, the federal government has invested millions to combine the minds of three existing institutes into one that can keep an eye on potential dangers ahead.

To understand the circuitry of the brain, it is often advantageous to visualize the processes of a single neuron or population of neurons. Identifying sites where a neuron, or neurons, originates and where it projects can allow a researcher to begin to map the circuitry underlying various processes, including sensory-guided behaviors. Furthermore, neural tracing allows one to map locations where processes terminate onto regions of the brain that may have known functions and sometimes to identify candidate upstream or downstream connections, based on proximity. Many methods of neural tracing are available; here, we focus on loading fluorescent dyes into a neuron (fluorescent dye filling). Different options for dyes exist to label neurites. Among the most versatile and easy to use are dextran amine–conjugated dyes. They fill neurons bidirectionally, not discriminating between anterograde or retrograde loading direction. Dye filling must be done in unfixed tissue, as the dye needs to move through the neurons; however, dextran amine conjugates are aldehyde-fixable and once cells have been fully loaded with dye the tissue can be fixed and subjected to immunostaining. Coupling neural tracing with immunofluorescence is a useful way to determine specific brain or ventral nerve cord (VNC) regions where a neuron projects. This protocol describes methods for loading dextran amine conjugated dyes into a sensory tissue in the mosquito to visualize sites of sensory neuron innervation in the central nervous system, as well as efferent projections to these structures. This protocol is described for Aedes aegypti, for which it was optimized, but it also works across a variety of insects.

Laboratory study of natural populations of mosquitoes can play a key role in determining the underlying causes of variation in burdens of mosquito-borne disease. Aedes aegypti is the main vector of the viruses that cause dengue, chikungunya, Zika, and yellow fever, making it a high priority for laboratory study. Ae. aegypti eggs provide an ideal starting point for new laboratory colonies. Eggs can be collected using ovicups, which are small plastic cups lined with seed-germination paper and partially filled with leaf-infused H₂O. Once collected, dry eggs will remain viable for months and can be safely transported long distances back to the laboratory as long as they are properly stored. This protocol provides step-by-step instructions for preparing for collecting, storing, and hatching Ae. aegypti eggs and has successfully yielded laboratory colonies from locations across both the native and invasive range of this species.

Creating transgenic mosquitoes allows for mechanistic studies of basic mosquito biology and the development of novel vector control strategies. CRISPR–Cas9 gene editing has revolutionized gene editing, including in mosquitoes. This protocol details part of the gene editing process of Aedes aegypti mosquitoes via CRISPR–Cas9, through testing and validating single-guide RNAs (sgRNAs). Gene editing activity varies depending on the sequence of sgRNAs used, so validation of sgRNA activity should be done before large-scale generation of mutants or transgenics. sgRNA is designed using online tools and synthesized in <1 h. Once mutants or transgenics are generated via embryo microinjection, sgRNA activity is validated by quick genotyping polymerase chain reaction (PCR) and DNA sequencing.

The Drosophila embryonic central nervous system has been used for decades as a model for understanding the genetic regulation of axon guidance and other aspects of neural development. Foundational studies using antibody staining to examine the embryonic ventral nerve cord in wild-type and mutant animals led to the discovery of evolutionarily conserved genes that regulate fundamental aspects of axon guidance, including midline crossing of axons. The development of the regular, segmentally repeating structure of axon pathways in the ventral nerve cord can illustrate basic principles of axon guidance to beginning students and can also be used by expert researchers to characterize new mutants, detect genetic interactions between known genes, and precisely quantify variations in gene function in engineered mutant lines. Here, we describe a protocol for collecting and fixing Drosophila embryos and visualizing axon pathways in the embryonic ventral nerve cord using immunofluorescence or immunohistochemical staining methods. As embryogenesis in Drosophila takes ~24 h to complete, a 1-d collection yields embryos representing all stages of development from newly fertilized through ready-to-hatch larvae, allowing investigation of multiple developmental events within a single batch of collected embryos. The methods described in this protocol should be accessible to introductory laboratory courses as well as seasoned investigators in established research laboratories.

Mosquitoes take blood meals from a diverse range of host animals and their host associations vary by species. Characterizing these associations is an important element of the transmission dynamics of mosquito-vectored pathogens. To characterize mosquito host associations, various molecular techniques have been developed, which are collectively referred to as blood meal analysis. DNA barcoding has diverse biological applications and is well-suited to mosquito blood meal analysis. The standard DNA barcoding marker for animals is a 5' fragment of the cytochrome c oxidase I (COI) gene. A major advantage of this marker is its taxonomic coverage in DNA sequence reference databases, making it feasible to identify a wider range of mosquito host species than with any other gene. However, the COI gene contains high sequence variation at potential priming sites between vertebrate orders. Coupled with the need for primer sequences to be mismatched with mosquito priming sites so that annealing to mosquito DNA is inhibited, it can be difficult to design primers suitable for blood meal analysis applications. Several primers are available that perform well in mosquito blood meal analysis, annealing to priming sites for most vertebrate host taxa, but not to those of mosquitoes. Because priming site sequence variation among vertebrate taxa can cause amplification to fail, a hierarchical approach to DNA barcoding-based blood meal analysis can be applied. In such an approach, no single primer set is expected to be effective for 100% of potential host species. If amplification fails in the initial reaction, a subsequent reaction is attempted with primers that anneal to different priming sites, and so on, until amplification is successful.

All PCR- and DNA-based blood meal analyses require host DNA from a mosquito blood meal to be effectively preserved between the time when the specimen is collected and the extraction of DNA. As soon as a mosquito ingests blood from a host animal, digestion of host cells and cellular components within the blood meal by enzymes in the mosquito midgut begins to degrade the host DNA templates that are the targets of polymerase chain reaction (PCR) amplification. Without effective preservation, host DNA is typically undetectable by PCR 48 h after feeding, because of digestion. Preservation methods for mosquito blood meals vary in their efficacy, and the logistics of fieldwork can limit the options for preservation of blood meals and maintenance of the integrity of host DNA. This protocol describes a method of blood meal preservation that is effective, convenient, and amenable to fieldwork in remote locations where cryopreservation at –20°C or –80°C may not be feasible. It uses a Flinders Technology Associates (FTA) card, which is a chemically treated card that lyses cells and allows nucleic acids to be preserved. This method is also expected to preserve the DNA or RNA of pathogens present within the engorged mosquito abdomen, including RNA viruses.

The insect eggshell is a multifunctional structure with several important roles, including generating an entry point for sperm via the micropyle before oviposition, serving as an oviposition substrate attachment surface, and functioning as a protective layer during embryo development. Eggshell proteins play major roles in eggshell tanning and hardening following oviposition and provide molecular cues that define dorsal–ventral axis formation. Precise eggshell formation during ovarian follicle maturation is critical for normal embryo development and the synthesis of a defective eggshell often gives rise to inviable embryos. Therefore, simple and accurate methods for identifying eggshell proteins will facilitate our understanding of the molecular pathways regulating eggshell formation and the mechanisms underlying normal embryo development. This protocol describes how to isolate and enrich eggshells from mature oocytes of Aedes aegypti mosquitoes and how to extract their eggshell proteins for liquid chromatography with tandem mass spectrometry (LC–MS/MS) proteomic analysis. Although this methodology was developed for studying mosquito eggshells, it may be applicable to eggs from a variety of insects. Mosquitoes are ideal model organisms for this study as their ovarian follicle development and eggshell formation are meticulously regulated by blood feeding and their follicles develop synchronously throughout oogenesis in a time-dependent manner.

In insects, oocyte resorption (oosorption) or follicular atresia is one of the key physiological processes and evolutionary strategies used to optimize reproductive fitness. Mosquitoes are ideal model organisms for studying egg maturation in arthropods, as their follicle development is initiated only following the ingestion of a blood meal, followed by a carefully orchestrated series of hormonally regulated events leading to egg maturation. A cohort of approximately 100 follicles per mosquito ovary begin developing synchronously. However, a significant fraction of follicles ultimately undergo apoptosis and oosorption, especially when available resources from the blood meal are limited. Therefore, simple, rapid, and reliable techniques to accurately evaluate follicular atresia are necessary to understand mechanisms underlying follicle development in insects. This protocol describes how to detect apoptotic follicle cells within the Aedes aegypti mosquito ovaries using a commercially available fluorescent-labeled inhibitor of caspases (FLICA). Caspases are key players in animal apoptosis. In this assay, the FLICA reagent enters the intracellular compartment of follicles in dissected mosquito ovaries and covalently binds to active caspases. The bound reagent remains within the cell and its fluorescent signal can be observed by confocal microscopy. Although this method was specifically developed for visualizing apoptotic ovarian follicles during Ae. aegypti mosquito egg development, it should be applicable to other mosquito tissues that undergo caspase-mediated program cell death in a time-dependent manner.

Transposon-mediated transgenesis has revolutionized both basic and applied studies of mosquito vectors of disease. Currently, techniques such as enhancer traps and transposon tagging, which rely on remobilizable insertional mutagenesis, are only possible with transposon-based vector systems. Here, we provide general descriptions of methods and applications of transposon-based mosquito transgenesis. The exact procedures must be adapted to each mosquito species and comparisons of some differences among different mosquito species are outlined. A number of excellent publications showing detailed and specific protocols and methods are featured and referenced.

The ancient burial structures, strikingly similar all across Europe and the mediterranean, have puzzled scientists and historians for centuries