on 15-Aug-2017 (Tue)

Nonocclusive mesenteric ischemia is the most likely cause of this patient's jejunal wall thickening and dilation, ongoing hypotension, fever, and abdominal pain.

Nonocclusive mesenteric ischemia is caused by decreased mesenteric perfusion in low-flow states such as heart failure, sepsis, profound hypotension, or hypovolemia. It may also occur with use of vasoactive medications such as vasopressors, ergots, triptans, cocaine, and digitalis.

Patients with cirrhotic-stage liver disease and a Model for End-Stage Liver Disease (MELD) score of 15 or greater have better survival with liver transplantation than without.

Patients with MELD scores greater than 10 are at risk of hepatic decompensation and mortality from any surgery, and especially with higher-risk surgeries such as a surgical portosystemic shunt

a TIPS is contraindicated in patients with MELD scores greater than 15 to 18 or serum bilirubin levels greater than 4 mg/dL (68.4 µmol/L), owing to high risk of mortality.

Laparoscopic cholecystectomy can be safely performed during pregnancy, particularly in the second trimester.

Bile acid dissolution therapy is expensive, requires long-term multiple daily dosing, necessitates repeated ultrasonography, and has a potential long-term risk for cancer in the remaining gallbladder. Finally, most nonsurgical therapies for gallstones are contraindicated in pregnant patients.

Extracorporeal shock-wave lithotripsy (ESWL) is reserved for patients with symptomatic gallstones who are poor candidates for surgery and in those patients with bile duct stones that are refractory to removal at ERCP owing to large size.

Peptic ulcer disease is the most common cause of upper gastrointestinal bleeding

This patient has upper GIB, which is predicted based on four aspects of his presentation: hematemesis, melena detected on physical examination, absence of blood clots in the stool, and an elevated blood urea nitrogen to creatinine ratio (>30).

The most common causes of upper GIB are peptic ulcer disease (34%), esophageal varices (33%), esophagitis (8%), and Mallory-Weiss tear (6%).

There is empirical evidence that the memory strategies enhance L2 vocabulary learning and retention compared with rote- learning or unstructured learning, that is, learning by using their own strategies (Rodriguez & Sadoski, 2000; Sanaoui, 1995). The effectiveness of the memory strate- gies, especially the keyword method, has been demonstrated not only with children (Pressley, 1977; Pressley & Levin, 1978; Pressley, Levin, & Miller, 1982; Ulanoff & Pucci, 1993) but also with adults who may be more attached to their own learning strat- egies (Beaton, Gruneberg, & Ellis, 1995; Desrochers, Wieland, & Cote, 1991; Gruneberg & Pascoe, 1996; Pressley & Ahmad, 1986)

In seeking evidence for establishing the effectiveness of the keyword method in relation with other vocabulary learning techniques, researchers have compared its effectiveness with that of other learning strategies. It has been demonstrated to be superior to learning a word in con- text, rote learning, using pictures, imaging the meaning of the word and semantic mapping.

the research finding that the keyword method is not as effective with experienced or mature language learners as with children and low-proficiency learners is well documented in literature (Hogben & Lawson, 1994; Levin, Pressley, McCormick, Miller, & Shriberg, 1979; Moore & Surber, 1992; Rodriguez & Sadoski, 2000; van Hell & Mahn, 1997). For example, Van Hell and Mahn (1997) conducted two experiments to look at the effective- ness of the keyword technique in comparison with rote learning with 36 experienced foreign language learners and 40 inexperienced language learners. They found that the keyword technique was not more beneficial than rote learning with the experienced learners. Not only were fewer words recalled by the experienced learners using the key- word method in the immediate and the delayed post-tests than those engaged in rote learning, but also more time was needed by them to recall the translations of the foreign target words. Thus the effectiveness of the keyword method with mature and experienced language learners is in doubt.

The word part vocabulary learning technique (Nation & Webb, 2011; Wei, 2012) is a mnemonic device based primarily on the interrelationships between the roots 1 of English words. For example, for learners with a vocabulary of 2,000 words, the high frequency known word ‘respect’ shares the same root -spect- with the lower frequency words ‘aspect’, ‘inspect’, ‘prospect’, ‘suspect’, ‘spectacle’, ‘perspective spectrum’, ‘respec- tive’, ‘retrospect’, etc. These words are similar in form as they all have the word part -spect- in them. Moreover, they are closely related in meaning because the meaning constant ‘look’ can be found in all of them

The word part technique consists of two stages of learning. The first stage requires the learner to identify the form similarity between the L2 new word and the linking word (the known L2 word) in order to establish a form-based association. The second stage requires the learner to recognize the meaning similarity shared by the new L2 word and the known L2 word in order to use the meaning constant to connect the new word

2007 Report of the Modern Language Association Ad Hoc Com- mittee on Foreign Languages, which recommended replacing the traditional two- tiered program structure with more coherent curricula that merge language and content

National recommendations for postpolypectomy surveillance intervals are as short as 3 to 6 months in patients with large (>2 cm) adenomas or adenomas with invasive cancer and favorable prognostic features.

pedunculated polyp may be considered adequately treated by endoscopic en bloc polypectomy alone if the lesion is confined to the submucosa and possesses no adverse histologic features such as poor differentiation, lymphatic or vascular invasion, or involved margins

Angiography should only be performed in patients with active overt bleeding, as it requires a bleeding rate greater than 0.5 mL/min. Complications such as acute kidney injury, organ necrosis, and vascular dissection/aneurysm can occur.

Balloon enteroscopy is used to visualize the small bowel. Latex balloons are mounted on an overtube that can deliver the enteroscope into the small bowel by successive inflation and deflation. Balloon enteroscopy can deliver the enteroscope orally or rectally (retrograde) and can be used for diagnosis and therapy. Complications of balloon enteroscopy are perforation and bleeding via avulsion of the bowel

Contraindications of ballon eneroscopy are radiation enteritis, severe ulceration, and recent bowel surgery

Technetium-labeled nuclear scans are used in patients with active bleeding (melena or hematochezia) who are transfusion dependent and hospitalized. This a diagnostic test and does not allow for therapeutic intervention

Fever accompanying abdominal pain in a critically ill patient should prompt an assessment for cholecystitis. Diagnosis is usually made with ultrasound findings of acute cholecystitis or a radionuclide biliary scan that fails to visualize the gallbladder

Approximately 50% of these high-risk patients with acalculus cholecystitis will develop cholangitis, empyema, gangrene, or gallbladder perforation during their hospitalization. Supportive treatment with intravenous antibiotic coverage of anaerobic and gram-negative bacteria is required. Definitive therapy with cholecystectomy is preferred but may be contraindicated in severely ill patients

We follow the convention that an uppercase letter represents a random variable and a lowercase letter represents an outcome or specific value of the random variable. Thus X refers to the random variable, and x refers to an outcome of X. We subscript outcomes, as in x₁ and x₂, when we need to distinguish among different outcomes in a list of outcomes of a random variable.

For example, a discrete random variable X can take on a limited number of outcomes x₁, x₂, …, x_n (n possible outcomes), or a discrete random variable Y can take on an unlimited number of outcomes y₁, y₂, … (without end).1 Because we can count all the possible outcomes of X and Y (even if we go on forever in the case of Y), both X and Y satisfy the definition of a discrete random variable. By contrast, we cannot count the outcomes of a continuous random variable. We cannot describe the possible outcomes of a continuous random variable Z with a list z₁, z₂, … because the outcome (z₁ + z₂)/2, not in the list, would always be possible. Rate of return is an example of a continuous random variable.

In working with a random variable, we need to understand its possible outcomes. For example, a majority of the stocks traded on the New Zealand Stock Exchange are quoted in ticks of NZ$0.01. Quoted stock price is thus a discrete random variable with possible values NZ$0, NZ$0.01, NZ$0.02

In most practical cases, a probability distribution is only a mathematical idealization, or approximate model, of the relative frequencies of a random variable’s possible outcomes.