Domain Summary

virusncov.com

Socolive - Xem bóng đá đẳng cấp trực tuyến mới nhất

Global rank: #18944590
Daily visitors: 0.09K
Monthly Visits: 2,609
Pageviews per user: 0.12
Registrar Abuse Contact Email: [email protected]
Registrant Phone:
Rating
TLD: com
IP Address: 104.21.79.114
Organization: Cloudflare, Inc.
Category: News and Media >
News and Media
virusncov.com Icon
virusncov.com
Last Status:
Online
Last Updated: 10 day ago
loading

About Website

Click here to check amazing linguascope live content for Vietnam. Otherwise, check out these important facts you probably never knew about virusncov.com

Visit virusncov.comRight Arrow
Trust Score DNS Competitors Traffic SSL HTTP Headers WHOIS Reviews SEO

virusncov.com Trust Score

virusncov.com is probably legit as the trust score is reasonable. Our algorithm rated virusncov.com a 89. Although our rating of virusncov.com is medium to low risk, we encourage you to always vote as the evaluation of the site is done automatically.

The trust rating is high. Might be safe.
Trustscore
89 / 100

What is your feeling about virusncov.com?

rating 10
rating 20
rating 30
rating 40
rating 50
No reviews. Be the first to Review.

Which Sites are Alternatives & Competitors to virusncov.com?

Explore the top alternatives and rivals of virusncov.com in November 2024, and assess their data relating to website traffic, SEO, Web Server Information, and Whois. Refer to the list below for the best competitors of virusncov.com, and simply click on each one to delve into their specific details.

Mentioned on Their Website:

  • lethbridgeherald.com
    Facts don't support need for more private care - Lethbridge Herald

    https://lethbridgeherald.com/commentary/letters-to-the-editor/2020/04/25/facts-dont-support-need-for-more-private-care/

    By Letter to the Editor on April 25, 2020. Gwyn Morgan’s piece (“System ill-prepared for crisis,” April 14) offers his opinion that Canada’s health-care system “is one of the least ...

  • peerj.com
    A descriptive study of random forest algorithm for predicting

    https://peerj.com/articles/9945/

    Background The outbreak of coronavirus disease 2019 (COVID-19) that occurred in Wuhan, China, has become a global public health threat. It is necessary to identify indicators that can be used as optimal predictors for clinical outcomes of COVID-19 patients. Methods The clinical information from 126 patients diagnosed with COVID-19 …

  • en.wikipedia.org
    Template:COVID-19 cases in South America - Wikipedia

    https://en.wikipedia.org/wiki/Template:COVID-19_cases_in_South_America

    The above documentation is transcluded from Template:COVID-19 cases in South America/doc. ( edit | history) Editors can experiment in this template's sandbox ( create | mirror) and testcases ( create) pages. Add categories to the /doc subpage. Subpages of …

  • ncbi.nlm.nih.gov
    A descriptive study of random forest algorithm for predicting …

    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7486830/

    The RF algorithm was built to predict the prognoses of COVID-19 patients based on the best subset, and the area under the ROC curve (AUC) of the test data was 100%. Moreover, two optimal clinical risk predictors, lactate dehydrogenase (LDH) and Myoglobin (Myo), were selected based on the Gini index. The univariable logistic …

  • scirp.org
    Natural Capital Exploration and Coronavirus Disease Spread in …

    https://www.scirp.org/journal/paperinformation?paperid=116366

    Abstract. The potential relationship between nature and Coronavirus disease 2019 (COVID-19) is provided using cross-sectional macro-data collected including 17 countries of major developed and developing nations whose number of cases were greater than 500 in March 15 th 2020. We found that the correlation coefficient is -0.46 between fisheries stock …

  • ncbi.nlm.nih.gov
    Epidemic Prevention During Work Resumption: A Case Study of …

    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7862944/

    In this study, Company C is selected as our research case. The primary reason we choose Company C as research case is that it made great achievements on epidemic prevention during work resumption. Company C is a Sino-US joint venture and a listed company in China, located in Qingdao, China.

  • ncbi.nlm.nih.gov
    A predictive paradigm for COVID-19 prognosis based on the …

    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8195146/

    Novel coronavirus disease 2019 (COVID-19) is an emerging, rapidly evolving crisis, and the ability to predict prognosis for individual COVID-19 patient is important for guiding …

  • ncbi.nlm.nih.gov
    Analysis of intervention effectiveness using early outbreak

    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8054527/

    After just three weeks the confirmed number of cases increased to 112, and after six weeks a total of 556 cases were identified including the first death from COVID-19 on April 4, …

  • iowa.forums.rivals.com
    COVID-19 to Kill MILLIONS of Americans?

    https://iowa.forums.rivals.com/threads/covid-19-to-kill-millions-of-americans.307624/

    Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases: "Things will get worse." How much worse it will get depends on 2 things, he said: 1. containing the influx of infected people coming from other countries 2. containing local outbreaks within the U.S...

  • sciencedirect.com
    A cross-sectional comparison of epidemiological and

    https://www.sciencedirect.com/science/article/pii/S1477893920301320

    1. Introduction. Coronaviruses are enveloped non-segmented positive-sense RNA viruses belonging to the family Coronaviridae, with a genome ranging from 26 to 32 kilobases in length [1].Among the several coronaviruses that are pathogenic to humans, most are associated with mild clinical symptoms, with two notable exceptions: severe …

  • frontiersin.org
    A Review on Plant Bioactive Compounds and Their Modes of …

    https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2020.589044/pdf?isPublishedV2=false

    A Review on Plant Bioactive Compounds and Their Modes of Action Against Coronavirus Infection Juwairiah Remali and Wan Mohd Aizat* Institute of Systems Biology (INBIOSIS), Universiti Kebangsaan Malaysia (UKM), Bangi, Malaysia

  • iowa.forums.rivals.com
    More Recovered than Active COVID-19 Cases

    https://iowa.forums.rivals.com/threads/more-recovered-than-active-covid-19-cases.306052/

    As the number of infected inches toward 100,000 world-wide, and the number of deaths approaches 3000, it looks like we have crossed welcome positive threshold. More than half of infections have now resolved. And, even more reassuring, more than half have recovered. Total infected without...

  • iowa.forums.rivals.com
    3,300 people across the world died in cars yesterday

    https://iowa.forums.rivals.com/threads/3-300-people-across-the-world-died-in-cars-yesterday.306872/

    3,300 people across the world died in cars yesterday ... Just sayin

  • bmcinfectdis.biomedcentral.com
    Reconstructing the cytokine view for the multi-view prediction of …

    https://bmcinfectdis.biomedcentral.com/articles/10.1186/s12879-023-08291-z

    Coronavirus disease 2019 (COVID-19) is a rapidly developing and sometimes lethal pulmonary disease. Accurately predicting COVID-19 mortality will …

  • bmj.com
    Re: Covid-19: Why Germany’s case fatality rate seems so low

    https://www.bmj.com/content/369/bmj.m1395/rr-4

    Dear Editor, We read with interest "Covid-19: Why Germany’s case fatality rate seems so low" [1] but we do not agree with the fact that the low Case fatality Rate (CFR) in Germany is partly due to the nation’s early and high level of testing among a wide sample of the German population.

  • ncbi.nlm.nih.gov
    Hand Sanitizers: A Review on Formulation Aspects, Adverse …

    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7246736/

    Figure 1. Various types of hand sanitizer dosage forms. To date, most effective hand sanitizer products are alcohol-based formulations containing 62%–95% of alcohol as it is capable of denaturing the proteins of microbes and inactivating viruses [ 19, 20 ]. There are a few challenges and concerns with regard to this formulation in terms of ...

  • linkedin.com
    THE FED ATTACKS CORONAVIRUS -- CHINA WOULD BE …

    https://www.linkedin.com/pulse/fed-attacks-coronavirus-china-would-proud-revolution-gerry-brady

    HOW DANGEROUS IS THE CORONAVIRUS? The Coronavirus can kill but so can car crashes, heart attacks, cancers and slipping in the shower. We must always remember that 60 million people die every year ...

  • github.com
    Corona_cases_notifier.py - GitHub

    https://github.com/Mary-Carter/Corona_case_notifier/blob/master/Corona_cases_notifier.py

    Navigation Menu Toggle navigation. Sign in Product

  • en.wikipedia.org
    Template talk:COVID-19 cases in Asia - Wikipedia

    https://en.wikipedia.org/wiki/Template_talk:COVID-19_cases_in_Asia

    Main page; Contents; Current events; Random article; About Wikipedia; Contact us; Donate

  • linkedin.com
    Analyzing the Impact of the Sturgis Rally via "Sturgis States"

    https://www.linkedin.com/pulse/analyzing-impact-sturgis-rally-via-states-don-f-wilson

    The data for this study came from USA Covid-19 Cases and Deaths Statistics (Update Live Cases: 12561109 / Deaths: 262534) (virusncov.com), extracted daily on the day after reporting. Small ...

  • ncbi.nlm.nih.gov
    Reconstructing the cytokine view for the multi-view prediction of …

    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10514938/

    Introduction. The new coronavirus pneumonia (COVID-19) is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) [].The disease has spread across 222 countries and caused more than six million deaths [].Because of the severe and rapidly developing symptoms of this disease, multiple studies have investigated …

  • linkedin.com
    alaaeldin alhessi on LinkedIn: Simon Sinek: If You Don't …

    https://www.linkedin.com/posts/alaaeldinalhessi_simon-sinek-if-you-dont-understand-people-activity-6610263210727706624-RiQG

    https://lnkd.in/fkgDx6c. Simon Sinek: If You Don't Understand People, You Don't Understand Business

  • linkedin.com
    alaaeldin alhessi on LinkedIn: #kudos #teamplayer

    https://www.linkedin.com/posts/alaaeldinalhessi_kudos-teamplayer-activity-6711952235070267393-WOC9

    Joseph Sleiman #Kudos It's honestly hard to explain how integral you are to this team #TeamPlayer

  • link.springer.com
    Restorative Justice and Non-Custodial Measures as Panacea

    https://link.springer.com/chapter/10.1007/978-3-031-13741-9_4

    The advent of the COVID-19 pandemic, in early 2020, took the entire world by storm and has affected the entire sphere of human endeavour. The pandemic poses severe threat to human life and has challenged governments and institutions to think out of the box on how to exist in the “new normal” way of life, which basically advocates social …

  • sciencedirect.com
    Molecular epidemiology analysis of early variants of

    https://www.sciencedirect.com/science/article/pii/S1567134821001283

    1. Introduction. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19), is a novel RNA virus from the Coronaviridae family (Wu et al., 2020).It is related to SARS-like coronaviruses found in bats (e.g., bat-SL-CoVZC45 and bat-SL-CoVZXC21) (Hu et al., 2018; Lu et al., 2020), and …

  • scirp.org
    COVID-19 Statistics (2020). COVID-19 Coronavirus 2019-nCov …

    https://www.scirp.org/reference/referencespapers?referenceid=2870569

    COVID-19 Statistics (2020). COVID-19 Coronavirus 2019-nCov Statistics Update (Live) 3,121,118 Cases and 216,508 Deaths.

  • link.springer.com
    Restorative Justice and Non-Custodial Measures as …

    https://link.springer.com/content/pdf/10.1007/978-3-031-13741-9_4

    6. C. C. ANI. 2.1 Table showing Total prison population in Nigeria. 6 . Year Total prison population . 2000 44,450 2002 40,048 2004 38,999 2006 40,953

  • ncbi.nlm.nih.gov
    Silver linings at the bench and bedside - PMC - National Center …

    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7429131/

    At the time of writing this editorial, over 20 million infections have been documented and nearly 750,000 have died (https://virusncov.com/), with the total number of cases likely …

  • worldometers.info
    United States COVID - Coronavirus Statistics - Worldometer

    https://www.worldometers.info/coronavirus/country/us/

    NOTE: As of April 13, 2024, the Coronavirus Tracker is no longer being updated due to the unfeasibility of providing statistically valid global totals, as the majority of countries have …

  • semrush.com
    virusncov.com Website Traffic, Ranking, Analytics [April 2023]

    https://www.semrush.com/website/virusncov.com/overview/

    virusncov.com Organic and Paid Website Traffic. Discover how your top competitor’s audience surfs the web so you can tailor your website experience perfectly …

  • en.wikipedia.org
    COVID-19 pandemic in North America - Wikipedia

    https://en.wikipedia.org/wiki/COVID-19_pandemic_in_North_America

    v. t. e. The first cases of the COVID-19 pandemic of coronavirus disease 2019 in North America were reported in the United States on 23 January 2020. Cases were reported in all North American countries after Saint Kitts and Nevis confirmed a case on 25 March, and in all North American territories after Bonaire confirmed a case on 16 April.

See More

DNS Lookup

DNS entries, such as A, NS, MX, and TXT records, are crucial for the functioning of the Internet. The A record maps a domain name to an IPv4 address, while the NS record specifies authoritative name servers for a domain. The MX record identifies the mail server responsible for receiving email messages for a domain. Additionally, the TXT record allows for the association of any text information with a domain name. These records play a vital role in ensuring proper communication and connectivity across the internet.

HostClassTTLTypeData
virusncov.comIN300Aip: 172.67.170.130
virusncov.comIN300Aip: 104.21.79.114
virusncov.comIN86400NStarget: rihana.ns.cloudflare.com
virusncov.comIN86400NStarget: harley.ns.cloudflare.com
virusncov.comIN1800SOAmname: harley.ns.cloudflare.comrname: dns.cloudflare.comserial: 2342103673refresh: 10000retry: 2400expire: 604800minimum-ttl: 1800
virusncov.comIN300AAAA
virusncov.comIN300AAAA

virusncov.com Traffic Analysis

According to global rankings, virusncov.com holds the position of #18944590. It attracts an approximate daily audience of 0.09K visitors, leading to a total of 199 pageviews. On a monthly basis, the website garners around 2.61K visitors.

Daily Visitors0.09K
Monthly Visits2.61K
Pages per Visit0.12
Visit Duration0:00:41
Bounce Rate25.57%
Want complete report?Full SEMrush Report >>
Daily Unique Visitors:
86
Monthly Visits:
2609
Pages per Visit:
0.12
Daily Pageviews:
199
Avg. visit duration:
0:00:41
Bounce rate:
25.57%
Monthly Visits (SEMrush):
3266

Traffic Sources

SourcesTraffic Share
Social:
0.00%
Paid Referrals:
0.00%
Mail:
0.00%
Search:
0.00%
Direct:
100.00%

Visitors by Country

CountryTraffic Share
Vietnam:
36.67%
United States:
27.56%
Taiwan:
16.09%
Germany:
15.19%
Brazil:
4.49%

SSL Checker - SSL Certificate Verify

An SSL certificate is a digital certificate that ensures a secure encrypted connection between a web server and a user's browser. It provides authentication and encryption to keep data private and protected during transmission. virusncov.com supports HTTPS, demonstrating their commitment to providing a secure browsing experience for users.

name
virusncov.com
hash
39992fe8
issuer
Let's Encrypt
version
2
serialNumber
390917305736149226992935014178354934238626
validFrom_time_t
1711788170
validTo_time_t
1719564169
signatureTypeSN
ecdsa-with-SHA384
signatureTypeLN
ecdsa-with-SHA384
signatureTypeNID
795
keyUsage
Digital Signature
extendedKeyUsage
TLS Web Server Authentication, TLS Web Client Authentication
basicConstraints
CA:FALSE
subjectKeyIdentifier
19:8F:F2:1A:89:65:25:E3:49:52:7A:70:B1:F8:6E:3C:5B:AE:23:77
authorityKeyIdentifier
keyid:5A:F3:ED:2B:FC:36:C2:37:79:B9:52:30:EA:54:6F:CF:55:CB:2E:AC
authorityInfoAccess
OCSP - URI:http://e1.o.lencr.org CA Issuers - URI:http://e1.i.lencr.org/
subjectAltName
DNS:*.virusncov.com, DNS:virusncov.com
certificatePolicies
Policy: 2.23.140.1.2.1

HTTP Headers

HTTP headers are additional segments of data exchanged between a client (e.g. a web browser) and a server during an HTTP request or response. They serve to provide instructions, metadata, or control parameters for the interaction between the client and server.

Status
HTTP/1.1 301 Moved Permanently
Date
Mon, 27 May 2024 18:05:18 GMT
Content-Type
text/html
Content-Length
167
Connection
keep-alive
Cache-Control
max-age=3600
Expires
Mon, 27 May 2024 19:05:18 GMT
Location
https://xoilactv9.net/
Report-To
{"endpoints":[{"url":"https:\/\/a.nel.cloudflare.com\/report\/v4?s=h%2B9jSuHU3de5CW3vUFUUOXYMv%2BsUuHXwAS7YEK5O0mEGRTi6JkrBCPOaAkZNPRqBJS32Wqg8esjWMs6wZ9Vsfmvy80iMl0mqIIA8YxXH2H921VSn5eWZqSZ13he70uwr"}],"group":"cf-nel","max_age":604800}
NEL
{"success_fraction":0,"report_to":"cf-nel","max_age":604800}
Server
cloudflare
CF-RAY
88a7eeabcbe496d7-SJC
Status
HTTP/1.1 403 Forbidden
Date
Mon, 27 May 2024 18:05:18 GMT
Content-Type
text/html; charset=UTF-8
Connection
close
Accept-CH
Sec-CH-UA-Bitness, Sec-CH-UA-Arch, Sec-CH-UA-Full-Version, Sec-CH-UA-Mobile, Sec-CH-UA-Model, Sec-CH-UA-Platform-Version, Sec-CH-UA-Full-Version-List, Sec-CH-UA-Platform, Sec-CH-UA, UA-Bitness, UA-Arch, UA-Full-Version, UA-Mobile, UA-Model, UA-Platform-Version, UA-Platform, UA
Critical-CH
Sec-CH-UA-Bitness, Sec-CH-UA-Arch, Sec-CH-UA-Full-Version, Sec-CH-UA-Mobile, Sec-CH-UA-Model, Sec-CH-UA-Platform-Version, Sec-CH-UA-Full-Version-List, Sec-CH-UA-Platform, Sec-CH-UA, UA-Bitness, UA-Arch, UA-Full-Version, UA-Mobile, UA-Model, UA-Platform-Version, UA-Platform, UA
Cross-Origin-Embedder-Policy
require-corp
Cross-Origin-Opener-Policy
same-origin
Cross-Origin-Resource-Policy
same-origin
Origin-Agent-Cluster
?1
Permissions-Policy
accelerometer=(),autoplay=(),browsing-topics=(),camera=(),clipboard-read=(),clipboard-write=(),geolocation=(),gyroscope=(),hid=(),interest-cohort=(),magnetometer=(),microphone=(),payment=(),publickey-credentials-get=(),screen-wake-lock=(),serial=(),sync-xhr=(),usb=()
Referrer-Policy
same-origin
X-Content-Options
nosniff
X-Frame-Options
SAMEORIGIN
cf-mitigated
challenge
cf-chl-out
H2czFBcK0d3/+wqKDvT0wn2k4AJU8eJFVqStP/Iz9RweAIJ7zmSfkBUwQ0BN9Ns3TRzQXqia9JE+1Qo8rL3nq4PkZ8Ato406inVW5WzjqFl4zOcAvJvxS5aqklPj1HqBryM2Oi4wjUnweI1LKpGKXQ==$3kffikrdcYTIaC4a/Vm2MA==
Cache-Control
private, max-age=0, no-store, no-cache, must-revalidate, post-check=0, pre-check=0
Expires
Thu, 01 Jan 1970 00:00:01 GMT
Server
cloudflare
CF-RAY
88a7eeac2c4822de-SJC

Where is virusncov.com hosted?

virusncov.com is likely hosted in various data centers located across different regions worldwide. The current data center mentioned is just one of many where the website may be hosted.

Whois Information

WHOIS protocol used to get domain/IP info. Common for reg details, ownership of a domain/IP. Check virusncov.com for reg/admin contact info, owner, org, email, phone, creation, and expiration dates.

Domain Updated Date:2024-03-30
Domain Created Date:2020-02-04
Domain Expiry Date:
Domain Name:
Registrar WHOIS Server:whois.dynadot.com
Registrar Abuse Contact Email:[email protected]
Registrar Abuse Contact Phone:+16502620100
Domain Registrar:Dynadot Inc
Domain Owner:

Domain Name: VIRUSNCOV.COM

Registry Domain ID: 2488274363_DOMAIN_COM-VRSN

Registrar WHOIS Server: whois.dynadot.com

Registrar URL: http://www.dynadot.com

Updated Date: 2024-03-30T09:34:39Z

Creation Date: 2020-02-04T03:33:21Z

Registry Expiry Date: 2025-02-04T03:33:21Z

Registrar: Dynadot Inc

Registrar IANA ID: 472

Registrar Abuse Contact Email: [email protected]

Registrar Abuse Contact Phone: +16502620100

Name Server: RIHANA.NS.CLOUDFLARE.COM

SEO Analysis

SEO analysis involves examining the performance of a website, including titles, descriptions, keywords, and website speed. It also includes identifying popular keywords and researching competitor websites to understand their strategies. The analysis aims to optimize the website's visibility and improve its ranking on search engines.

Title Tag:
Socolive - Xem bóng đá đẳng cấp trực tuyến mới nhất

Length: 67 characters

Title tags are usually best kept short, within 50-70 characters. It's important to note that search engines will typically read the entire title tag even if it exceeds 70 characters, but there is a chance they may cut it off or disregard it.

Meta Description:

No meta description found.

Length: 0 characters

When crafting website descriptions, keep in mind that search engines only show the first 150-160 characters in search results. To ensure your entire description is visible, aim for a length of 25-160 characters. If your description is too long, it may get cut off. Conversely, if it's too short, search engines may add text from elsewhere on your page. Additionally, search engines may modify the description you provide to better match the user's search intent. It's best to strike a balance between brevity and relevance for optimal visibility.

Meta Keywords:

No meta keywords found.

In the realm of search engine optimization, the meta keywords tag has become a relic of the past due to its potential for misuse, ultimately leading major search engines to disregard it in their ranking algorithms.

Keywords Cloud:
Term Count Density
xem 3 37.50%
socolive 2 25.00%
tuy 2 25.00%
ngay 1 12.50%

A crucial factor in search engine optimization is keyword density, which refers to the proportion of a particular keyword present in the text of a webpage. In order to achieve high rankings on search engine results pages, it is essential to maintain the appropriate keyword density for your primary keyword.

Image Alt Attribute:
5 images found in your page, and 4 images are without "ALT" text.

What is the issue about?
The tag does not have an ALT attribute defined. As a general rule, search engines do not interpret the content of image files. The text provided in the attribute enables the site owner to provide relevant information to the search engine and to the end user. Alt text is helpful to end users if they have images disabled or if the image does not properly load. In addition, the Alt text is utilized by screen readers. Make sure that your Alt text is descriptive and accurately reflects what the image represents and supports the content on the page.

How to fix?
Use the <img alt> attribute to write descriptive content for the image: <img source='pic.gif' alt='Accurate and descriptive keyword text that represents the image.' />.

Website Speed Test (Desktop):
0.01 seconds

Website speed is a measurement of how fast the content on your page loads. Website speed is one of many factors involved in the discipline of search engine optimization (SEO), but it is not the only one. In a recent study, the average load time for a web page was 3.21s.

Top Organic Search Terms:
Term Search Volume Traffic Traffic (%)
linguascope live 90 0 0%

CO-Hosted

CoHosted refers to a situation where multiple domain names (websites) are using the same IP address to point to their respective web servers. They could be owned by different individuals or organizations and may serve entirely different purposes.

virusncov.com
universetoday.com
pravyprostor.net

People reviews about virusncov.com

Very positive reviews

rating 5

Total reviews: 2
Average score: 5 stars

The total score is based on reviews found on the following sites
Scamadviser: 5/5 stars, 2 reviews

Add your review

rating 1 rating 2 rating 3 rating 4 rating 5

Very positive reviews

rating 5

Total reviews: 2
Average score: 5 stars

The total score is based on reviews found on the following sites
Scamadviser: 5/5 stars, 2 reviews


Back Top
Feedback