gt.geometric topology – “Basic” loops on standardly embedded surfaces

Take a genus $g$ surface $S$ standardly embedded in $mathbb{R}^3$, by which I mean it is unknotted. Surface $S$ bounds a volume $V$ that deformation retracts on a standardly embedded planar graph $G$ with $beta_1 = g$, and that only has degree $3$ vertices.

Among the loops on $S$ that are null homotopic in $V$, there is a subset that are boundaries of embedded disks in $V$ that intersect $G$ exactly once for some choice of $G$ as above.

Do these loops (or perhaps close variants) have a name? Do they have an alternate definition?

entities – How can I track how embedded media is used across my site?

My site uses the core Media module, Entity Embed, and LinkIt to reference media and other entities in various ways.

I want to keep track of which media is embedded on which nodes.

I tried adding an entity reference field to media on my content types, but this means that I have to add the media twice: to the field where I actually embed the media and to the entity reference field to track it.

Is there a better way?

usability testing – Why is embedded help not popular?

Embedded help is only not popular when it gets in the way of the user trying to do their work. No one is going to complain about embedded help on their page when it’s actually truly helpful to them And it doesn’t prevent them from doing their job.

I interact with online embedded help all the time on web sites I visit. Most of them are done in a very nice and classy way (but some of them are not…). Inline help icons, text, buttons or even dialog boxes that pop up once in a while with critical information that I would not have known about otherwise. If done in a tasteful way, it all helps ends up helping the end user in my opinion.

inline help in Google Analytics

Active help versus passive help both have their place. Active help can get annoying if it’s not helping anymore and just being intrusive and getting in the way. However, there are definitely ways of embedding active help in an application that truly helps the user. Example that comes to mind is how a tooltip that appears in Upwork when I put my email address in a conversation.

Tooltip that comes up automatically when you put an email address in an upwork conversation

The tooltip is letting me know that protections provided by upwork differ if I take my conversations outside of the platform. That’s useful to know for an employer like myself just in case if there is any conflicts that later arise with the contractor.

At the end of the day, the simple rule is that embedded help has to be helpful for it to be perceived as useful and not intrusive by the end user.

wysiwyg – How select view mode of Remote Video embedded Media for Simplenews display?

When I send out an Article as a Newsletter I want to be able to have any Remote Video embedded in the body of the Article displayed as a link; but when viewed normally in the web page, displayed as a Remote Video for viewing in the page.

I have created two Media View Modes in Display modes but I can’t see a way of having the Remote Video display differently in each of these two cases: 1] default web page; and 2] emailed newsletter

I can choose the display mode of a Remote Video when included in the page as a separate field, but not when embedded in the body via the Media icon in CKEditor

Note: I have chosen to include just the link in the email but it would be nice, but I assume not possible, to have the Remote Video thumbnail or actual video frame displayed in the newsletter.
Of course, were I to display the Remote Video itself in the newsletter I get “Blocked by X-Frame-Options Policy” or an email that some mail clients seem to choke on.

MCU (embedded C): Use nested if / elses or use ugly function?

I am writing the driver code for the SPI peripheral (as part of a tutorial) on a Nucleo64 (STM32F446RE). The instructor recommends writing this code:

// General macros
#define EnableStatus uint8_t
#define DISABLE      0
#define ENABLE       !DISABLE

void SPI_EnablePeripheralClock(SPI_RegDef_t *pSPI, EnableStatus status)
    if (status) {
        if (pSPIx == SPI1)
        else if (pSPI == SPI2)
        // ... done for 4 SPI modules
    } else { 
        if (pSPIx == SPI1)
        else if (pSPI == SPI2)
        // ... done for 4 SPI modules

// You can treat RCC->APB2ENR as the value at some address. ENA() sets a bit. DIS() clears a bit.
#define SPI1_CLK_ENA()       (RCC->APB2ENR |= (1 << 12))
#define SPI2_CLK_ENA()       (RCC->APB1ENR |= (1 << 14))
#define SPI1_CLK_DIS()       (RCC->APB2ENR &= ~(1 << 12))
#define SPI2_CLK_DIS()       (RCC->APB1ENR &= ~(1 << 14))
#define IO volatile

typedef struct {
    IO uint32_t CR1;        // Control Reg. 1
    IO uint32_t CR2;        // Control Reg. 2
    IO uint32_t SR;         // Status Reg.
    IO uint32_t DR;         // Data Reg.
    IO uint32_t CRCPR;      // CRC Polynomial Reg.
    IO uint32_t RXCRCR;     // RX CRC Reg.
    IO uint32_t TXCRCR;     // TX CRC Reg.
    IO uint32_t I2SCFGR;    // I2S Configuration Reg.
    IO uint32_t I2SPR;      // I2S Prescaler Reg.
} SPI_RegDef_t;
#define SPI1 ((SPI_RegDef_t*)SPI1_BASEADDR)
#define SPI2 ((SPI_RegDef_t*)SPI2_BASEADDR)

I don't like the if-elses string in the function and it's basically setting or clearing a bit in some direction. So I rewrote it like this:

// Assigns the boolean value b to the p'th bit position (0-based indexing) of the number `num`.
void BitAssign(volatile uint32_t *num, uint8_t p, bool b)
    b = !!b; // booleanize b (if it was previously non-zero, it is now 1 otherwise it's 0)
    *num = (*num & ~(1UL << p)) | (b << p);

// To be used as first argument in SPI_EnablePeripheralClock() and other functions
#define SPI1 1
#define SPI2 2
#define SPI3 3
#define SPI4 4

void SPI_EnablePeripheralClock(uint8_t SPIx, EnableStatus status)
    // 12, 14, 15, 13 are values provided by the datasheet
    if (SPIx == SPI1)
        BitAssign(&RCC->APB2ENR, 12, status);
    else if (SPIx == SPI2)
        BitAssign(&RCC->APB1ENR, 14, status);
    else if (SPIx == SPI3)
        BitAssign(&RCC->APB1ENR, 15, status);
    else if (SPIx == SPI4)
        BitAssign(&RCC->APB2ENR, 13, status);

This avoids relying on ENA () / DIS () functions (I can remove them) and uses bit operations to do the big mapping. I'm not sure if BitAssign() it's a good idea as you might have to overload it for non-volatile parameters.

al.gebraic geometry – About embedded resolution

Leave $ M $ be a Kähler collector and $ V $ a singular hypersurface of $ M $. Suppose we get an embedded resolution $ M ^ { prime} $ of $ V $ in $ M $ finally many explosions along smooth centers.

My question (maybe stupid): in the above configuration, why can we see $ M ^ { prime} $ as a submanifold in a finite product of multiple Kähler .

Self-signed certificates on embedded IoT device

I have multiple IoT devices that will connect to a cloud based platform to control these devices (IoT node running bare metal arm SoC).

I would like to know how to configure each IoT node to generate a self-signed certificate and how this element can improve the general security of the system.

This certificate will only be used during IoT appliance deployment and will be used to prevent potential ManInTheMiddle attacks. Is it really useful for this specific case?

IKM Embedded C Assessment Test

Has anyone taken or has experience in the IKM Integrated C Assessment Test? I found some information online, but couldn't find a lot of information, sample questions and test rules? Any word of advice?

Psyplay self embedded with dbmovies |

Proceed with caution, I am sure he is known for his bad practices in the past. I.E by injecting your own ads into scripts



seo – How to create video sitemap for my website when video is hosted on vimeo and embedded using?

I'd like to know what to do when creating a video sitemap when the embedded player is from Vimeo.

I am very new to the world of SEO and I am learning by doing and reading the official documentation.

For example, the video page on my website is

This has 1 video on one page. If you look at the source of the page, the relevant part is as follows.

Now, I read the documentation on the Google Video sitemap at and the relevant tag you see is

However, I don't know how to use this tag, would the following work when creating the index?

I'm not sure if this is correct since the description of it says

A URL pointing to a player for a specific video. Usually, this is the information in the src element of an  tag. Must not be the same as the  URL. For YouTube video, this value is used rather than video:content_loc. This is the equivalent of VideoObject.embedUrl in structured data.
Must not be the same as the  URL.

Any help is really appreciated!