Beryllium 10 cosmogenic dating places massive Zion valley floor landslide and resulting lake to 4800 years ago

© 2016 Peter Free

Citation — to study

Jessica J. Castleton, Jeffrey R. Moore, Jordan Aaron, Marcus Christl, and Susan Ivy-Ochs, Dynamics and legacy of 4.8 ka rock avalanche that dammed Zion Canyon, Utah, USA, Geological Society of America 26(6): 4-9, DOI: 10.1130/GSATG269A.1 (June 2016)

Citation — to press release

Lee Siegel, How a Huge Landslide Shaped Zion National Park, University of Utah (26 May 2016) (with photographs and simulation graphics)

Cool catastrophes?

What follows will mean more to people who have been to Zion National Park in the United States.

From the University of Utah:

A Utah mountainside collapsed 4,800 years ago in a gargantuan landslide known as a “rock avalanche,” creating the flat floor of what is now Zion National Park by damming the Virgin River to create a lake that existed for 700 years.

Computer simulations matched known landslide deposits and show the huge slide rushed southeast across Zion Canyon in about 20 seconds, with an average speed of 112 mph and a peak speed of 180 to 200 mph.

“It was certainly moving more than 150 mph when the huge wall and peak crashed down,” [Jeffrey] Moore says. Then, for 30 more seconds, the slide debris spread up and down Zion Canyon. “By a minute it was pretty much done.”

“The original deposit was 2 miles long and just under a mile wide,” with a maximum thickness of 650 feet and average thickness of 310 feet, he says, adding the landslide’s lower end is at the road junction “right at the mouth of Zion Canyon.”

“We have conducted a rigorous and complete analysis of this landslide for the first time,” Moore says. The study concluded the landslide most likely happened 4,800 years ago as single event, with a range of uncertainty so that it could have happened as early as 5,200 years ago or as recently as 4,400 years ago.

The method exploits the fact that after a landslide, boulders atop the slide have surfaces exposed to the sky for the first time. Particles from incoming cosmic rays begin to hit the boulder surfaces, creating beryllium-10. The longer a boulder is exposed, the greater the amount of beryllium-10, allowing scientists to determine when the boulder’s surface first was exposed by the landslide.

With permission from the National Park Service, Moore and colleagues sampled 12 boulders from the landslide’s surface, crushed the notebook-sized rock samples and analyzed their beryllium-10 content.

© 2016 Lee Siegel, How a Huge Landslide Shaped Zion National Park, University of Utah (26 May 2016) (extracts)

Lee Siegel’s excellent press release contains photographs and graphics.

The same message in scientific language

From the abstract:

The Sentinel rock avalanche blocked the mouth of Zion Canyon, Utah, USA, over a distance of 3.3 km and created a large lake that filled the canyon floor with sediment, transforming this iconic desert landscape.

Reconstructing topography before and after the failure, we calculate an original deposit volume of 286 million m3 with maximum thickness of 200 m. New cosmogenic nuclide surface exposure ages of 12 boulders from across the deposit reveal a mean age of 4.8 ± 0.4 ka and are consistent with single-event emplacement.

Results of 3D numerical runout simulations agree well with mapped deposit boundaries and thickness, affirming our hypothesized failure scenario and indicating an average runout velocity of 50 m/s.

Following partial breach of the landslide dam, we estimate that water levels stabilized for ~700 yr until the lake filled with sediment. Deposited lacustrine clays reveal a period when Zion Canyon was filled by the 3 km2 Sentinel Lake extending more than 7 km upstream.

© 2016 Jessica J. Castleton, Jeffrey R. Moore, Jordan Aaron, Marcus Christl, and Susan Ivy-Ochs, Dynamics and legacy of 4.8 ka rock avalanche that dammed Zion Canyon, Utah, USA, Geological Society of America 26(6): 4-9, DOI: 10.1130/GSATG269A.1 (June 2016) (at Abstract) (extracts)

The moral? — Understanding pertinent geology makes travel more interesting

Appreciation to Lee Siegel and the University of Utah for their visually informative overview.

Small British study shows physician reluctance — to implement other than face to face patient interactions — demonstrating the gap between hype and reality

© 2016 Peter Free

Citation — to study

Heather Brant, Helen Atherton, Sue Ziebland, Brian McKinstry, John L Campbell, and Chris Salisbury, Using alternatives to face-to-face consultations: a survey of prevalence and attitudes in general practice, British Journal of General Practice, DOI: 10.3399/bjgp16X685597 (online first, 24 May 2016)

The gist — “Ya gotta come in”

From the abstract:

Despite considerable rhetoric about the need for general practices to offer alternatives to face-to-face consultations, such as telephone, email, and internet video consultations, the extent to which such technologies are actually used at present is unclear.

A postal questionnaire survey was sent to each of the GPs and practice managers of 421 practices between January and May 2015.

A response was received from 319/421 practices (76%).

Although the majority of the practices reported that they were conducting telephone consultations frequently (n = 211/318, 66%), fewer were implementing email consultations (n = 18/318, 6%), and most (n = 169/318, 53%) had no plans to introduce this.

None were currently using internet video, and 86% (n = 273/318) had no plans to introduce internet video consultations.

Despite policy pressure to introduce consultations by email and internet video, there is a general reluctance among GPs to implement alternatives to face-to-face consultations.

 

This identifies a substantial gap between rhetoric and reality in terms of the likelihood of certain alternatives (email, video) changing practice in the near future.

© 2016 Heather Brant, Helen Atherton, Sue Ziebland, Brian McKinstry, John L Campbell, and Chris Salisbury, Using alternatives to face-to-face consultations: a survey of prevalence and attitudes in general practice, British Journal of General Practice, DOI: 10.3399/bjgp16X685597 (online first, 24 May 2016) (extracts)

The moral? — Inertia is in charge

I recently had to drive for 90 minutes just to have a nurse check surgical site healing. Something that I could have much more easily done via an already installed video and medical communications link from my primary care manager’s office.

The technology is here. Just not the will to use it. When money keeps flowing in, why change?

Surgeons apparently differ wildly regarding the wisdom of doing surgery for identical routine conditions — says a possibly indicative UCLA study

© 2016 Peter Free

Citation — to study

Greg D. Sacks, Aaron J. Dawes, Susan L. Ettner, Robert H. Brook, Craig R. Fox, Marcia M. Russell, Clifford Y. Ko, and Melinda Maggard-Gibbons, Impact of a Risk Calculator on Risk Perception and Surgical Decision Making: A Randomized Trial, Annals of Surgery, DOI: 10.1097/SLA.0000000000001750 (published ahead of print, 19 May 2016)

Citation — to press release

University of California – Los Angeles Health Sciences, To operate or not to operate: Serious question with no clear answers, ScienceDaily (20 May 2016)

An invitation to confusion

From the press release:

In the first study, the researchers found that surgeons differ in their recommendations for surgery largely because they differ in how they perceive the risks and benefits of operating versus not operating. The surgeons’ estimates of these risks and benefits varied widely. When assessing outcomes such as the likelihood that a patient would suffer a serious complication, for instance, one surgeon could perceive zero risk for a given procedure while another would see a 100 percent chance of that same procedure leading to a major complication.

For the second study, the same team of researchers examined how the use of a surgical risk calculator would influence surgeons’ decision to pick up a scalpel under the same set of hypothetical circumstances.

The online risk calculator, developed by the American College of Surgeons National Surgical Quality Improvement Program, uses national registry data to gauge the chances of postoperative complications based on type of surgery, patient demographics, and the state of a patient’s health.

While the calculator led surgeons to make more accurate predictions on average and resulted in less variance in their judgements, there was no change in a surgeon’s likelihood of recommending an operation.

The take-home message of both studies is that there may not always be clear answers on the best treatment. For that reason, patients might benefit from getting involved in the decision-making process, Sacks said.

“In areas of such uncertainty, these studies suggest that the best we can do is estimate the risks and benefits of each possible treatment and then work with the patient to find a treatment that matches his or her preferences and values,” he said.

© 2016 University of California – Los Angeles Health Sciences, To operate or not to operate: Serious question with no clear answers, ScienceDaily (20 May 2016) (extracts)

The numbers

From the abstract:

We asked a national sample of surgeons to assess the risks (probability of serious complications or death) and benefits (recovery) of operative and nonoperative management and to rate their likelihood of recommending an operation (5-point scale) for 4 detailed clinical vignettes wherein the best treatment strategy was uncertain

Surgeons were randomized to the clinical vignettes alone (control group; n = 384) or supplemented by data from a risk calculator (risk calculator group; n = 395). We compared surgeons’ judgments and decisions between the groups.

Surgeons exposed to the risk calculator judged levels of operative risk that more closely approximated the risk calculator value (RCV) compared with surgeons in the control group

mesenteric ischemia: 43.7% vs 64.6% . . . (RCV = 25%)

gastrointestinal bleed: 47.7% vs 53.4% . . . (RCV = 38%)
small bowel obstruction: 13.6% vs 17.5% . . . (RCV = 14%);
appendicitis: 13.4% vs 24.4% . . . (RCV = 5%)].

Surgeons exposed to the risk calculator also varied less in their assessment of operative risk

(standard deviations:

mesenteric ischemia 20.2% vs 23.2% . . .

gastrointestinal bleed 17.4% vs 24.1% . . .

small bowel obstruction 10.6% vs 14.9% . . .

appendicitis 15.2% vs 21.8% . . .

However, averaged across the 4 vignettes, the 2 groups did not differ in their reported likelihood of recommending an operation . . . .

Exposure to risk calculator data leads to less varied and more accurate judgments of operative risk among surgeons, and thus may help inform discussions of treatment options between surgeons and patients. Interestingly, it did not alter their reported likelihood of recommending an operation.

© 2016 Greg D. Sacks, Aaron J. Dawes, Susan L. Ettner, Robert H. Brook, Craig R. Fox, Marcia M. Russell, Clifford Y. Ko, and Melinda Maggard-Gibbons, Impact of a Risk Calculator on Risk Perception and Surgical Decision Making: A Randomized Trial, Annals of Surgery, DOI: 10.1097/SLA.0000000000001750 (published ahead of print, 19 May 2016)  (at Abstract) (paragraph split)

The moral? — Irrationality rules?

Notice the surgeons’ sizable departures from the risk calculator.
And even after using the calculator to improve their sense of the risk considerations, the sample group apparently did not alter their surgical recommendations.

I doubt that patient discussion will much improve the situation. Most patients are not knowledgeable enough to have workable intuitions regarding the elements being considered.

p62 signaling protein levels reportedly predict liver cancer recurrence — but neither the abstract nor press release bother to quantify anything — which makes both essentially meaningless

© 2016 Peter Free

Citation — to study

Atsushi Umemura, Feng He, Koji Taniguchi, Hayato Nakagawa, Shinichiro Yamachika, Joan Font-Burgada, Zhenyu Zhong, Shankar Subramaniam, Sindhu Raghunandan, Angeles Duran, Juan F. Linares, Miguel Reina-Campos, Shiori Umemura, Mark A. Valasek, Ekihiro Seki, Kanji Yamaguchi, Kazuhiko Koike, Yoshito Itoh, Maria T. Diaz-Meco, Jorge Moscat, and Michael Karin, p62, Upregulated during Preneoplasia, Induces Hepatocellular Carcinogenesis by Maintaining Survival of Stressed HCC-Initiating Cells, Cancer Cell DOI: 10.1016/j.ccell.2016.04.006 (in press, 19 May 2016)

Citation— to press release

University of California – San Diego, High levels of protein p62 predict liver cancer recurrence, EurekAlert! (19 May 2016)

Too vaguely synopsized to be persuasive

From the “summary” (abstract) — extracts:

p62 is a ubiquitin-binding autophagy receptor and signaling protein that accumulates in premalignant liver diseases and most hepatocellular carcinomas (HCCs).

Here we show that p62 is necessary and sufficient for HCC induction in mice and that its high expression in non-tumor human liver predicts rapid HCC recurrence after curative ablation.

© 2016 Atsushi Umemura, Feng He, Koji Taniguchi, Hayato Nakagawa, Shinichiro Yamachika, Joan Font-Burgada, Zhenyu Zhong, Shankar Subramaniam, Sindhu Raghunandan, Angeles Duran, Juan F. Linares, Miguel Reina-Campos, Shiori Umemura, Mark A. Valasek, Ekihiro Seki, Kanji Yamaguchi, Kazuhiko Koike, Yoshito Itoh, Maria T. Diaz-Meco, Jorge Moscat, and Michael Karin, p62, Upregulated during Preneoplasia, Induces Hepatocellular Carcinogenesis by Maintaining Survival of Stressed HCC-Initiating Cells, Cancer Cell DOI: 10.1016/j.ccell.2016.04.006 (in press, 19 May 2016) (at Summary) (extracts)

This is meaningless. What levels of p62 and what relative risk? Not even ballpark figures are presented.

One essentially has to take the authors’ implied assurance that they’ve found something. And that the something they found will presumably significantly matter to liver cancer patients. But the abstract contains no data to make either presumption persuasive.

The press release is no better:

In this study, Karin’s team looked at non-cancerous liver samples collected from people who had undergone previous treatment to completely destroy their liver cancers. They graded the livers from 0 to 3 based on the average number of p62-positive aggregates detected.

Seventy-nine of 121 specimens were p62 positive. Using the medical records corresponding to each liver sample, the team also noted the number of years each patient survived disease-free.

The researchers found that people with high-grade p62 were significantly more likely to see their cancer return and less likely to survive cancer-free than people with low or no p62.

They found the same correlation when they looked at the link between the p62 gene and survival outcomes for an additional 450 liver cancer patients whose genomic data and clinical records are available in national research databases.

© 2016 University of California – San Diego, High levels of protein p62 predict liver cancer recurrence, EurekAlert! (19 May 2016) (extracts)

Without numbers, “less” and “more” mean nothing. And what kind of “significantly” are we talking about?

The moral? — Probably good science, but miserably synopsized

Selling one’s methods and findings in summary is part of an effective scientist’s job. Delivering at least the appearance of analytical competence is important. This paper’s “summary” (abstract) and its press release arguably do neither very well.

Eating more than one potato serving per month —is associated with hypertension in women — but not men

© 2016 Peter Free

Citation — to study

Lea Borgi, Eric B Rimm, Walter C Willett, and John P Forman, Potato intake and incidence of hypertension: results from three prospective US cohort studies, BMJ 353: i2351, DOI: http://dx.doi.org/10.1136/bmj.i2351 (17 May 2016)

This is a bit surprising

From the abstract:

Participants [were] 62 175 women in Nurses’ Health Study, 88 475 women in Nurses’ Health Study II, and 36 803 men in Health Professionals Follow-up Study who were non-hypertensive at baseline.

Compared with consumption of less than one serving a month, the random effects pooled hazard ratios for four or more servings a week were 1.11 . . . for baked, boiled, or mashed potatoes,

1.17 . . . for French fries,

and 0.97 . . . for potato chips.

In substitution analyses, replacing one serving a day of baked, boiled, or mashed potatoes with one serving a day of non-starchy vegetables was associated with decreased risk of hypertension (hazard ratio 0.93, 0.89 to 0.96).

Higher intake of baked, boiled, or mashed potatoes and French fries was independently and prospectively associated with an increased risk of developing hypertension in three large cohorts of adult men and women.

© 2016 Lea Borgi, Eric B Rimm, Walter C Willett, and John P Forman, Potato intake and incidence of hypertension: results from three prospective US cohort studies, BMJ 353: i2351, DOI: http://dx.doi.org/10.1136/bmj.i2351 (17 May 2016) (at Abstract) (paragraph split)

These are not large effects. Eleven percent increased risk for hypertension associated with eating more than one serving per month of “regularly” cooked potatoes. And 17 percent for the same thing with French fries.

Caveats — despite the huge sample sizes

From the body of the paper:

This study has several limitations.

Firstly, random misclassification of potato intake could have occurred because all dietary assessment methods are imperfect; however, this type of random error in assessment of exposure would tend to attenuate our findings and therefore underestimate the true association.

Secondly, participants self reported a diagnosis of hypertension and direct blood pressure measurements were not obtained. However, our method of ascertainment of hypertension (self report by trained health professionals of similar educational backgrounds) has been extensively validated in all three cohorts.

Thirdly, our population consists mostly of non-Hispanic white people of a relatively uniform socioeconomic status. However, we have no reason to suspect that the biological response to diet is qualitatively different across ethnic groups. Fourthly, as with any observational study, our findings could be explained by residual confounding; for example, potatoes are often consumed with salt and added fat (such as butter or margarine). The increased sodium content could explain the association of boiled/baked potatoes with hypertension. However, our results did not materially change after we adjusted for intake of sodium or trans and saturated fat.

We also controlled for many known and proposed risk factors for hypertension that were collected in a prospective fashion. Furthermore, the relative uniformity of socioeconomic status reduces the likelihood of confounding by unmeasured variables.

© 2016 Lea Borgi, Eric B Rimm, Walter C Willett, and John P Forman, Potato intake and incidence of hypertension: results from three prospective US cohort studies, BMJ 353: i2351, DOI: http://dx.doi.org/10.1136/bmj.i2351 (17 May 2016) (at Limitations of study) (extracts)

I particularly object to this statement:

However, we have no reason to suspect that the biological response to diet is qualitatively different across ethnic groups.

That’s untrue on its face. The Inuit, by way of randomly chosen example, appear to have a much higher (healthier) tolerance for animal fat than other groups. And anyone familiar with medical practice across what I will loosely call “differing human genomes” knows that sometimes surprising medical differences between them exist.

Methodologically, given that all three samples were self-reported, this study’s ability to reliably track and compare varying sodium and fat intakes (from one person to another) is also arguably suspect.

The moral? — Quantitatively small hypertensive effect with questionable causation

I would be more concerned about potatoes’ hyperglycemic effect, than something as methodologically arguable as these findings — which were imputed from studies that were not designed to sort out a multitude of potentially contributing factors.

There are limits to what one can accurately do (to overcome methodological gaps in the original studies) with retrospectively applied statistical methods.