How do Android developers improve non-functional properties of software?

Nowadays there is an increased pressure on mobile app developers to take non-functional properties into account. An app that is too slow or uses much bandwidth will decrease user satisfaction, and thus can lead to users simply abandoning the app. Although automated software improvement techniques exist for traditional software, these are not as prevalent in the mobile domain. Moreover, it is yet unknown if the same software changes would be as effective. With that in mind, we mined overall 100 Android repositories to find out how developers improve execution time, memory consumption, bandwidth usage and frame rate of mobile apps. We categorised non-functional property (NFP) improving commits related to performance to see how existing automated software improvement techniques can be improved. Our results show that although NFP improving commits related to performance are rare, such improvements appear throughout the development lifecycle. We found altogether 560 NFP commits out of a total of 74,408 commits analysed. Memory consumption is sacrificed most often when improving execution time or bandwidth usage, although similar types of changes can improve multiple non-functional properties at once. Code deletion is the most frequently utilised strategy except for frame rate, where increase in concurrency is the dominant strategy. We find that automated software improvement techniques for mobile domain can benefit from addition of SQL query improvement, caching and asset manipulation. Moreover, we provide a classifier which can drastically reduce manual effort to analyse NFP improving commits.

Effect of crude protein and phosphorus level on growth performance, bone mineralisation and phosphorus, calcium and nitrogen utilisation in grower-finisher pigs.

Two experiments in a 2 x 2 factorial arrangement were conducted to evaluate the effect of crude protein (CP) (130 vs. 200 g/kg) and phosphorus (P) (4.0 vs. 6.0 g total P/kg) level in a phytase supplemented diet (500 FTU [phytase units]/kg) in grower-finisher pigs. Owing to the design of the experiment, as dietary P level increased, there was also an increase in dietary calcium (Ca) level in order to maintain a dietary Ca to P ratio of 1.6:1. In Experiment 1, four diets were fed to 56 pigs (n = 14, initial body weight [BW] 36.7 +/- 4.2 kg) to investigate the interaction between CP and P on growth performance, bone mineralisation and digesta pH. Experiment 2 consisted of 16 entire male pigs (n = 4; offered identical diets to that offered in Experiment 1) for the determination of total tract apparent digestibility and nitrogen (N), P and Ca utilisation. There was an interaction between CP and P level on bone ash, bone P and bone Ca concentrations (p < 0.05). Pigs offered low CP-low P diets had a higher bone ash, P and Ca concentrations than pigs offered high CP-low P diets. However, there was no effect of CP level at high P levels on bone ash, P and Ca concentrations. Pigs offered low P diets had a lower ileal pH compared with pigs offered high P diets (p < 0.05). In conclusion, offering pigs a high CP-low P, phytase-supplemented diet resulted in a decrease in bone mineralisation.

Effect of dietary mineral level and inulin inclusion on phosphorus, calcium and nitrogen utilisation, intestinal microflora and bone development.

BACKGROUND: An experiment was conducted to investigate the interaction between dietary phosphorus (P) level (4 vs 6 g total P kg(-1)) and inulin inclusion (0 vs 20 g kg(-1)) on coefficients of total tract apparent digestibility, nitrogen (N), P and calcium (Ca) utilisation, bone mineralisation, selected gastrointestinal microflora, intestinal volatile fatty acid concentrations and digesta pH in the ileum, caecum and proximal colon. Owing to the design of the experiment, as dietary P level increased, there was also an increase in dietary Ca level in order to maintain a sustainable dietary Ca/P ratio. Entire male finisher pigs (n = 10 per treatment) with a similar initial body weight (51 kg, standard deviation 2.4 kg) were used. RESULTS: Inulin inclusion lowered (P < 0.01) Enterobacteriaceae populations in the proximal colon compared with pigs offered diets without added inulin. However, intestinal bacterial populations of Lactobacillus and Bifidobacterium spp. were unaffected. Inulin inclusion had no effect on mineral digestibility or bone mineralisation. Pigs offered low P and Ca diets had lower (P < 0.01) bone mineralisation than pigs offered high P and Ca diets. CONCLUSION: Intestinal bacterial populations of Enterobacteriaceae in the proximal colon were lowered by inulin inclusion. Inulin inclusion did not affect P, Ca or N utilisation or bone mineralisation in the finisher pig when offered either a low or a high P diet. Increasing the P and Ca content of the diet led to an increase in bone mineralisation.

The effect of dietary Laminaria-derived laminarin and fucoidan on nutrient digestibility, nitrogen utilisation, intestinal microflora and volatile fatty acid concentration in pigs.

BACKGROUND: In experiment 1, 30 boars were assigned to one of five treatments (n = 6): T1, 0 g kg(-1) seaweed extract (SWE); T2, 0.7 g kg(-1) SWE; T3, 1.4 g kg(-1) SWE; T4, 2.8 g kg(-1) SWE and T5, 5.6 g kg(-1) SWE. The extract contained laminarin and fucoidan only and was extracted from Laminaria spp. In experiment 2, 28 boars were assigned, in a 2 x 2 factorial to one of four treatments (n = 7): T1, control; T2, control plus 300 mg laminarin; T3, control plus 240 mg fucoidan; T4, control plus 300 mg laminarin and 240 mg fucoidan kg(-1) diet. RESULTS: In experiment 1 there was a response to SWE on colonic Bifidobacterium spp. (P < 0.01 quadratic), Enterobacterium spp. (quadratic P < 0.05) and on caecal Enterobacterium spp. (quadratic P < 0.05). In experiment 2 there was an interaction (P < 0.05) between laminarin and fucoidan supplementation on Enterobacterium spp. in the proximal and distal colon. Pigs offered laminarin had reduced Enterobacterium spp. compared with pigs offered the control diet. However, the combination of laminarin and fucoidan had increased Enterobacterium spp. compared with alone. Pigs offered diets containing fucoidan had increased Lactobacilli spp. in the proximal colon (P < 0.05) and distal colon (P < 0.001) compared with non-fucoidan diets. CONCLUSION: Overall, the reductions in intestinal Enterobacterium spp. and increases in Lactobacilli spp. obtained suggest that laminarin and fucoidan may provide a dietary means to improve gut health in pigs.

Prochlorperazine vs. promethazine for headache treatment in the emergency department: a randomized controlled trial.

Headache is a very common medical complaint. Four to six percent of the population will have a debilitating headache in their lifetime; and 1-2% of all Emergency Department (ED) visits involve patients with headaches. Although promethazine is used frequently, it has never been studied as a single-agent treatment in undifferentiated headache. We hypothesized that promethazine would be superior to prochlorperazine in the treatment of headache. We conducted a prospective, double-blinded, randomized, controlled trial on patients presenting to our ED between May and August 2005 with a chief complaint of headache. Each subject was randomized to receive either intravenous promethazine 25 mg or prochlorperazine 10 mg, and graded the intensity of their headache on serial 100-mm visual analog scales (VAS). Patients with dystonic reactions or akathesia were treated with diphenhydramine. Adequate pain relief was defined as an absolute decrease in VAS score of 25 mm. After discharge from the ED, patients were queried regarding the recurrence of headache symptoms, the need for additional pain medications, and the occurrence of any side effects since discharge. Thirty-five patients were enrolled in each group. Both drugs were shown to be effective in treatment of headaches. Prochlorperazine provided a faster rate of pain resolution and less drowsiness when compared to promethazine. Both medications were individually effective as abortive therapy for headache. Prochlorperazine was superior to promethazine in the rate of headache reduction and rate of home drowsiness, with similar rates of akathesia, nausea resolution, patient satisfaction, and headache recurrence within 5 days of discharge.

The influence of manure composition on emissions of odour and ammonia from finishing pigs fed different concentrations of dietary crude protein.

An investigation was conducted into the influence of manure composition on the odour emission rate (OER) and the emission rate of ammonia (NH(3)), when diets containing 130, 160, 190 and 210gkg(-1) crude protein (CP) were fed to finishing pigs. A group of four boars and four gilts, housed in environmentally sealed pens, were assigned to each diet for a 23-day experimental period which was replicated three times (n=3). Ventilation air from each pen was sampled for NH(3) and odour, by olfactometry, on four days during the trial period. Simultaneous collections of manure were taken from the surface and base of each pit. The pH and the concentrations of dry matter, total Kjeldahl nitrogen (TKN), total ammoniacal nitrogen (TAN) and volatile fatty acids in the manure were measured. Manure composition differed between samples from the surface and base of the pit (P<0.05). Reducing dietary CP concentration decreased the emission of NH(3) (linear, P<0.001). The acetic acid:propionic acid ratio in manure samples was correlated to OER (r=0.79, P<0.001). There was a quadratic relationship between dietary CP concentration and OER (P<0.05). OER decreased between 210gkg(-1) and 160gkg(-1) CP and increased between 160gkg(-1) and 130gkg(-1) CP. In conclusion, reducing dietary crude protein levels could be used effectively to reduce ammonia emissions and OER, although no significant advantage was to be gained in OER from reducing crude protein level below 160gkg(-1).